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Wagner was born in Leipzig, Germany; the son of Dr Julius Wagner who was the Head of Chemistry at the local institute and secretary of the German Bunsen Society of Physical Chemistry. Wagner graduated from the University of Munich and gained his PhD at the University of Leipzig in 1924 supervised by Max Le Blanc with a dissertation on the reaction rate in solutions, "Beiträge zur Kenntnis der Reaktionsgeschwindigkeit in Lösungen". | 1 | Solid-state chemistry |
Tantalum(III) chloride can form complexes with some ligands as a monomer or dimer.
Complexes include Ta(=C-CMe)(PMe)Cl, [TaCl(P(CHCH)THF]μ-N and [TaClTHF]μ-N (dinitrogen complexes).
As a dimer, complexes include TaCl(SCH) (SCH=tetrahydrothiophene). TaCl(SMe), TaCl(thiane) and TaCl(thiolane) have a double bond between the two tantalum atoms, and two bridging chlorides, and a bridging ligand. | 1 | Solid-state chemistry |
Icosahedral twinning has been seen in face-centered-cubic metal nanoparticles that have nucleated: (i) by evaporation onto surfaces, (ii) out of solution, and (iii) by reduction in a polymer matrix.
Quasicrystals are un-twinned structures with long range rotational but not translational periodicity, that some initially tried to explain away as icosahedral twinning. Quasicrystals generally form only when the compositional makeup (e.g. of two dissimilar metals such as titanium and manganese) serves as an antagonist to formation of one of the more common close-packed space-filling forms. | 0 | Colloidal Chemistry |
In materials science and colloidal chemistry, the term colloidal particle refers to a small amount of matter having a size typical for colloids and with a clear phase boundary. The dispersed-phase particles have a diameter between approximately 1 and 1000 nanometers. Colloids are heterogeneous in nature, invisible to the naked eye, and always move in a random zig-zag-like motion known as Brownian motion. The scattering of light by colloidal particles is known as Tyndall effect. | 0 | Colloidal Chemistry |
Miedema introduced his approach in several papers, beginning in 1973 in Philips Technical Review Magazine with "A simple model for alloys".
Miedema described his motivation with "Reliable rules for the alloying behaviour of metals have long been sought. There is the qualitative rule that states that the greater the difference in the electronegativity of two metals, the greater the heat of formation - and hence the stability. Then there is the Hume-Rothery rule, which states that two metals that differ by more than 15% in their atomic radius will not form substitutional solid solutions. This rule can only be used reliably (90 % success) to predict poor solubility; it cannot predict good solubility. The author has proposed a simple atomic model, which is empirical like the other two rules, but nevertheless has a clear physical basis and predicts the alloying behaviour of transition metals accurately in 98 % of cases. The model is very suitable for graphical presentation of the data and is therefore easy to use in practice."
Free web based applications include Entall and Miedema Calculator. The latter was reviewed and improved in 2016, with an extension of the method. The original Algol program was ported to Fortran. | 1 | Solid-state chemistry |
If the hyperfine field fluctuates during the lifetime of the intermediate level due to jumps of the probe into another lattice position or from jumps of a near atom into another lattice position, the correlation is lost. For the simple case with an undistorted lattice of cubic symmetry, for a jump rate of for equivalent places , an exponential damping of the static -terms is observed:
Here is a constant to be determined, which should not be confused with the decay constant . For large values of , only pure exponential decay can be observed:
The boundary case after Abragam-Pound is , if , then: | 1 | Solid-state chemistry |
Salinity from irrigation can occur over time wherever irrigation occurs, since almost all water (even natural rainfall) contains some dissolved salts. When the plants use the water, the salts are left behind in the soil and eventually begin to accumulate. This water in excess of plant needs is called the leaching fraction. Salination from irrigation water is also greatly increased by poor drainage and use of saline water for irrigating agricultural crops.
Salinity in urban areas often results from the combination of irrigation and groundwater processes. Irrigation is also now common in cities (gardens and recreation areas). | 1 | Solid-state chemistry |
Artificial nanoparticles can be created from any solid or liquid material, including metals, dielectrics, and semiconductors. They may be internally homogeneous or heterogenous, e.g. with a core–shell structure.
There are several methods for creating nanoparticles, including gas condensation, attrition, chemical precipitation, ion implantation, pyrolysis, hydrothermal synthesis, and biosynthesis. | 0 | Colloidal Chemistry |
MALDI matrix compounds such as α-cyano-4-hydroxycinnamic acid have been linked through a linker consisting of an unsymmetric formaldehyde acetals to dodecanol. This type of cleavable detergent is inherently compatible with MALDI and does not have to be removed prior to analysis.
UV light- or fluoride-cleavable surfactants have also been developed but are not in current use. | 0 | Colloidal Chemistry |
To understand how band structure changes relative to the Fermi level in real space, a band structure plot is often first simplified in the form of a band diagram. In a band diagram the vertical axis is energy while the horizontal axis represents real space. Horizontal lines represent energy levels, while blocks represent energy bands. When the horizontal lines in these diagram are slanted then the energy of the level or band changes with distance. Diagrammatically, this depicts the presence of an electric field within the crystal system. Band diagrams are useful in relating the general band structure properties of different materials to one another when placed in contact with each other. | 1 | Solid-state chemistry |
Several strategies have been proposed as a way to protect those who are at greatest risk of occupational exposure to PFAS, including exposure monitoring, regular blood testing, and the use of PFAS-free alternatives. For example, fluorine-free firefighting foam and plant-based ski wax contain no PFAS and greatly reduce the occupational hazards associated with certain professions. | 0 | Colloidal Chemistry |
In modern solid-state physics, it is common to classify systems according to the kind of degrees of freedom they have available, like electron (metals) or spin (magnetism). In crystals that can display the JTE, and before this effect is realised by symmetry-breaking distortions, it is found that there exists an orbital degree of freedom consisting of how electrons occupy the local degenerate orbitals. As initially discussed by Kugel and Khomskii, not all configurations are equivalent. The key is the relative orientation of these occupied orbital, in the same way that spin orientation is important in magnetic systems, and the ground state can only be realised for some particular orbital pattern. Both this pattern and the effect giving rise to this phenomenon is usually denominated orbital-ordering.
In order to predict the orbital-ordering pattern, Kugel and Khomskii used a particularisation of the Hubbard model. In particular they established how superexchange interactions, usually described by the Anderson–Kanamori–Goodenough rules, change in the presence of degenerate orbitals. Their model, using a pseudospin representation for the local orbitals, leads to a Heisenberg-like model in which the ground state is a combination of orbital and spin patterns. Using this model it can be shown, for example, that the origin of the unusual ground insulating ferromagnetic state of a solid like KCuF can be traced to its orbital ordering.
Even when starting from a relatively high-symmetry structure the combined effect of exchange interactions, spin–orbit coupling, orbital-ordering and crystal deformations activated by the JTE can lead to very low symmetry magnetic patterns with specific properties. For example, in CsCuCl an incommensurable helicoidal pattern appears both for the orbitals and the distortions along the -axis. Moreover, many of these compounds show complex phase diagrams when varying temperature or pressure. | 1 | Solid-state chemistry |
Tin(IV) oxide, also known as stannic oxide, is the inorganic compound with the formula SnO. The mineral form of SnO is called cassiterite, and this is the main ore of tin. With many other names, this oxide of tin is an important material in tin chemistry. It is a colourless, diamagnetic, amphoteric solid. | 1 | Solid-state chemistry |
The small size of nanoenzymes (or nanozymes) (1–100 nm) has provided them with unique optical, magnetic, electronic, and catalytic properties. Moreover, the control of surface functionality of nanoparticles and the predictable nanostructure of these small-sized enzymes have allowed them to create a complex structure on their surface that can meet the needs of specific applications | 0 | Colloidal Chemistry |
An emulsion dispersion is thermoplastics or elastomers suspended in a liquid state by means of emulsifiers. | 0 | Colloidal Chemistry |
In 1914 black phosphorus, a layered, semiconducting allotrope of phosphorus, was synthesized. This allotrope exhibits high carrier mobility. In 2014, several groups isolated single-layer phosphorene, a monolayer of black phosphorus. It attracted renewed attention because of its potential in optoelectronics and electronics due to its band gap, which can be tuned via modifying its thickness, anisotropic photoelectronic properties and carrier mobility. Phosphorene was initially prepared using mechanical cleavage, a commonly used technique in graphene production.
In 2023, alloys of arsenic-phosphorene displayed higher hole mobility than pure phosphorene and were also magnetic. | 1 | Solid-state chemistry |
After about 1820, New York replaced New England as the most important source; by 1840 the center was in Ohio. Potash production was always a by-product industry, following from the need to clear land for agriculture. | 1 | Solid-state chemistry |
Saiful presented the 2016 Royal Institution Christmas Lectures, entitled "Supercharged: Fuelling the Future" on the theme of energy, a commemorative lecture series for the BBC which celebrated 80 years since the Christmas Lectures were first broadcast on television in 1936. The lectures were broadcast on BBC Four, and achieved over 3.5 million interactions through the BBC broadcasts and social media. Saiful was interviewed before these lectures for articles in The Guardian. A demonstration in these lectures led to a Guinness World Record for the highest voltage (1,275 Volts) produced by a fruit battery using more than 1,000 lemons. Saiful later broke that record in 2021 after using 2,923 lemons to produce 2,307.8 Volts.
Saiful has served on the Diversity Committee of the Royal Society, and was selected for the Royal Societys Inspiring Scientists' project that recorded the life stories of British scientists with minority ethnic heritage in partnership with National Life Stories at the British Library. His outreach activities include talks on energy materials to student audiences using 3D glasses organised by the TTP Education in Action at the UCL Institute of Education, London. He was interviewed for The Life Scientific programme on BBC Radio 4 in October 2019.
On 23 November 2022, Saiful was an invited speaker at the Brian Cox & Robin Ince's Compendium of Reason charity event, which was at the Royal Albert Hall. | 1 | Solid-state chemistry |
The original Asakura–Oosawa model considered only hard-core interactions. In such an athermal mixture the origin of depletion forces is necessarily entropic. If the intermolecular potentials also include repulsive and/or attractive terms, and if the solvent is considered explicitly, the depletion interaction can have additional thermodynamic contributions.
The notion that depletion forces can also be enthalpically driven has surfaced due to recent experiments regarding protein stabilization induced by compatible osmolytes, such as trehalose, glycerol, and sorbitol. These osmolytes are preferentially excluded from protein surfaces, forming a layer of preferential hydration around the proteins. When the protein folds - this exclusion volume diminishes, making the folded state lower in free energy. Hence the excluded osmolytes shift the folding equilibrium towards the folded state. This effect was generally thought to be an entropic force, in the spirit of the original Asakura–Oosawa model and of macromolecular crowding. However, thermodynamic breakdown of the free-energy gain due to osmolyte addition showed the effect is in fact enthalpically driven, whereas entropy can even be disfavorable.
For many cases, the molecular origin of this enthalpically driven depletion force can be traced to an effective "soft" repulsion in the potential of mean force between macromolecule and cosolute. Both Monte-Carlo simulations and a simple analytic model demonstrate that when the hard-core potential (as in Asakura and Oosawa's model) is supplemented with an additional repulsive "softer" interaction, the depletion force can become enthalpically dominated. | 0 | Colloidal Chemistry |
Michel Pouchard is the author of nearly 400 articles published in the best journals in solid-state chemistry and materials science and some fifteen patents. | 1 | Solid-state chemistry |
The solid is isostructural with (has the same structure as) fluorite (calcium fluoride), where each U is surrounded by eight O nearest neighbors in a cubic arrangement. In addition, the dioxides of cerium, thorium, and the transuranic elements from neptunium through californium have the same structures. No other elemental dioxides have the fluorite structure. Upon melting, the measured average U-O coordination reduces from 8 in the crystalline solid (UO cubes), down to 6.7±0.5 (at 3270 K) in the melt. Models consistent with these measurements show the melt to consist mainly of UO and UO polyhedral units, where roughly of the connections between polyhedra are corner sharing and are edge sharing. | 1 | Solid-state chemistry |
Realizing the modest thermal conductivity enhancement in conventional nanofluids, a team of researchers at Indira Gandhi Centre for Atomic Research Centre, Kalpakkam developed a new class of magnetically polarizable nanofluids where the thermal conductivity enhancement up to 300% of basefluids is demonstrated. Fatty-acid-capped magnetite nanoparticles of different sizes (3-10 nm) have been synthesized for this purpose. It has been shown that both the thermal and rheological properties of such magnetic nanofluids are tunable by varying the magnetic field strength and orientation with respect to the direction of heat flow. Such response stimuli fluids are reversibly switchable and have applications in miniature devices such as micro- and nano-electromechanical systems.
In 2013, Azizian et al. considered the effect of an external magnetic field on the convective heat transfer coefficient of water-based magnetite nanofluid experimentally under laminar flow regime. Up to 300% enhancement obtained at Re=745 and magnetic field gradient of 32.5 mT/mm. The effect of the magnetic field on the pressure drop was not as significant. | 0 | Colloidal Chemistry |
Roy was born in Ranchi, Bihar Province, India, the son of Narenda Kumar and Rajkumari Roy.
Rustum took a Cambridge School Certificate from Saint Pauls School Darjeeling. Rustum studied physical chemistry at Patna University, gaining his bachelors degree in 1942 and master's degree in 1944. The following year he began study at Pennsylvania State University and earned his Ph.D. in engineering ceramics in 1948.
Rustum Roy married fellow materials scientist Della Marie Martin on June 8 that year. | 1 | Solid-state chemistry |
Felser studied chemistry and physics at the University of Cologne, completing there both her diploma in solid state chemistry (1989) and her doctorate in physical chemistry (1994). After postdoctoral fellowships at the Max Planck Institute for Solid State Research in Stuttgart, Germany (1994-1995) with Arndt Simon and Ole Krogh Andersen, she moved to the Centre National de la Recherche Scientifique (CNRS) in Nantes, France (1995-1996), where she worked in the group of Jean Rouxel. Afterwards, she joined the Johannes Gutenberg University of Mainz in 1996 as an assistant professor (C1). She resided there in 2002 and was appointed to a full professor (C4) in 2003.
In 1999, she was a visiting professor at Princeton University and, in 2000, at the University of Caen. From 2009 to 2010 she was visiting professor at Stanford University and in 2019 visiting professor at Harvard University in the department Physics/ Applied Physics.
Since September 2011 she is a director of the Max Planck Institute for Chemical Physics of Solids and Professor hon. at the TU Dresden. Since June 2023, Felser has been Vice President of the Max Planck Society (CPT section). | 1 | Solid-state chemistry |
SP-B is one of four proteins commonly found in surfactant, the other three being surfactant protein A (SP-A), surfactant protein C (SP-C), and surfactant protein D (SP-D). These four are highly interconnected in their functions in surfactant. For example, though the mechanism is not yet understood, SP-B functions in the post-translational modification of SP-C, and mature SP-C is not formed without SP-B.
SP-C assists in the functions of SP-B, and is most similar to SP-B of the three other surfactant proteins. It is smaller, only 35 amino acids long, and is found embedded in lipid structures much like SP-B.
SP-A and SP-D, known together as collectins, are more distinct from SP-B than SP-C. They are hydrophilic, so they are found in the solution, and function in immune response instead of lipid arrangement and surface tension reduction. SP-A is actually a name for two very similar proteins, SP-A1 and SP-A2.
Along with SP-A, B, C, and D, blood plasma proteins are found in very small quantities in surfactant as well. | 0 | Colloidal Chemistry |
Witold Rybczynski and Jacques Hadamard developed an equation to calculate the velocity of bubbles that rise in foam with the assumption that the bubbles are spherical with a radius .
with velocity in units of centimeters per second. ρ and ρ is the density for a gas and liquid respectively in units of g/cm and ῃ and ῃ is the dynamic
viscosity of the gas and liquid respectively in units of g/cm·s and g is the acceleration of gravity in units of cm/s.
However, since the density and viscosity of a liquid is much greater than the gas, the density and viscosity of the gas can be neglected, which yields the new equation for velocity of bubbles rising as:
However, through experiments it has been shown that a more accurate model for bubbles rising is:
Deviations are due to the Marangoni effect and capillary pressure, which affect the assumption that the bubbles are spherical.
For laplace pressure of a curved gas liquid interface, the two principal radii of curvature at a point are R and R. With a curved interface, the pressure in one phase is greater than the pressure in another phase. The capillary pressure P is given by the equation of:
where is the surface tension. The bubble shown below is a gas (phase 1) in a liquid (phase 2) and point A designates the top of the bubble while point B designates the bottom of the bubble.
At the top of the bubble at point A, the pressure in the liquid is assumed to be p as well as in the gas. At the bottom of the bubble at point B, the hydrostatic pressure is:
where ρ and ρ is the density for a gas and liquid respectively. The difference in hydrostatic pressure at the top of the bubble is 0, while the difference in hydrostatic pressure at the bottom of the bubble across the interface is gz(ρ − ρ). Assuming that the radii of curvature at point A are equal and denoted by R and that the radii of curvature at point B are equal and denoted by R, then the difference in capillary pressure between point A and point B is:
At equilibrium, the difference in capillary pressure must be balanced by the difference in hydrostatic pressure. Hence,
Since, the density of the gas is less than the density of the liquid the left hand side of the equation is always positive. Therefore, the inverse of R must be larger than the R. Meaning that from the top of the bubble to the bottom of the bubble the radius of curvature increases. Therefore, without neglecting gravity the bubbles cannot be spherical. In addition, as z increases, this causes the difference in R and R too, which means the bubble deviates more from its shape the larger it grows.
Foam destabilization occurs for several reasons. First, gravitation causes drainage of liquid to the foam base, which Rybczynski and Hadamar include in their theory; however, foam also destabilizes due to osmotic pressure causes drainage from the lamellas to the Plateau borders due to internal concentration differences in the foam, and Laplace pressure causes diffusion of gas from small to large bubbles due to pressure difference. In addition, films can break under disjoining pressure, These effects can lead to rearrangement of the foam structure at scales larger than the bubbles, which may be individual (T1 process) or collective (even of the "avalanche" type). | 0 | Colloidal Chemistry |
The technique involves pouring a suspension of magnetized ceramic micro-plates. Pores in the plaster mold absorb the liquid from the suspension, solidifying the material from the outside in. The particles are subjected to a strong magnetic field as they solidify that causes them to align in one direction. The field's orientation is changed at regular intervals, moving the plates still in suspension, without disturbing already-solidified plates. By varying the composition of the suspension and the direction of the platelets, a continuous process can produce multiple layers with differing material properties in a single object. The resulting objects can closely imitate their natural models. | 0 | Colloidal Chemistry |
Nazeeruddin is a co-author on numerous peer-reviewed papers, book chapters, and is a co-inventor on many patents. According to Thomson Reuters he has been named a "Highly Cited Researcher" in chemistry, materials science and engineering in 2016 and 2017, and was included in the list of "Worlds Most Influential Scientific Minds" from all scientific domains. As stated in the ISI listing he is one of the most cited chemists with more than 126000 citations and an h-index of 160. His group has earned worldwide recognition and leadership in Perovskite solar cells as evidenced by The Times of Higher Education named him "the top 10 researchers in the world working on the high impact perovskite materials and devices". Nazeeruddin was listed as one of the Top 2% Most-Cited Scientists in the world from the list published by Stanford University in October 2022.
He is an elected member of the European Academy of Sciences, and is a fellow of The Royal Society of Chemistry. Fellow of Telangana Academy of Sciences, and Member of the Swiss Chemical Society. He was awarded the 34th Khwarizmi International Award in Basic Sciences, 2021.
Since 2018 he has been a jury member of the Rei Jaume I foundation in Spain.
He is the recipient of the best paper award from the journal Inorganics, the EPFL Excellence Prize (1998 and 2006), the Brazilian FAPESP fellowship award (1999), the Japanese Government Science & Technology Agency Fellowship (1998), and Government of India National Scholar award (1987-1989).
He is Editor in Chief, Chemistry of Inorganic Materials, an Advisory Board member at Advanced Functional Materials, an Associated Editor at Energy Chem, an Editorial Advisory Board member at Scientific Reports, an Editorial Advisory Board at RRL Solar, and an Editorial Advisory Board member at Artificial Photosynthesis. | 1 | Solid-state chemistry |
As the most prevalent morphology of nanomaterials used in consumer products, nanoparticles have an enormous range of potential and actual applications. Table below summarizes the most common nanoparticles used in various product types available on the global markets.
Scientific research on nanoparticles is intense as they have many potential applications in pre-clinical and clinical medicine, physics, optics, and electronics. The U.S. National Nanotechnology Initiative offers government funding focused on nanoparticle research. The use of nanoparticles in laser dye-doped poly(methyl methacrylate) (PMMA) laser gain media was demonstrated in 2003 and it has been shown to improve conversion efficiencies and to decrease laser beam divergence. Researchers attribute the reduction in beam divergence to improved dn/dT characteristics of the organic-inorganic dye-doped nanocomposite. The optimum composition reported by these researchers is 30% w/w of SiO (~ 12 nm) in dye-doped PMMA. Nanoparticles are being investigated as potential drug delivery system. Drugs, growth factors or other biomolecules can be conjugated to nano particles to aid targeted delivery. This nanoparticle-assisted delivery allows for spatial and temporal controls of the loaded drugs to achieve the most desirable biological outcome. Nanoparticles are also studied for possible applications as dietary supplements for delivery of biologically active substances, for example mineral elements. | 0 | Colloidal Chemistry |
To be of use for connecting molecules, MWs need to self-assemble following well-defined routes and form reliable electrical contacts between them. To reproducibly self-assemble a complex circuit based on single molecules. Ideally, they would connect to diverse materials, such as gold metal surfaces (for connections to outside world), biomolecules (for nanosensors, nanoelectrodes, molecular switches) and most importantly, they must allow branching. The connectors should also be available of pre-determined diameter and length. They should also have covalent bonding to ensure reproducible transport and contact properties.
DNA-like molecules have specific molecular-scale recognition and can be used in molecular scaffold fabrication. Complex shapes have been demonstrated, but unfortunately metal coated DNA which is electrically conducting is too thick to connect to individual molecules. Thinner coated DNA lacks electronic connectivity and is unsuited for connecting molecular electronics components.
Some varieties of carbon nanotubes (CNTs) are conducting, and connectivity at their ends can be achieved by attachment of connecting groups. Unfortunately manufacturing CNTs with pre-determined properties is impossible at present, and the functionalized ends are typically not conducting, limiting their usefulness as molecular connectors. Individual CNTs can be soldered in an electron microscope, but the contact is not covalent and cannot be self-assembled.
Possible routes for the construction of larger functional circuits using MoSI MWs have been demonstrated, either via gold nanoparticles as linkers, or by direct connection to thiolated molecules. The two approaches may lead to different possible applications. The use of GNPs offers the possibility of branching and construction of larger circuits. | 1 | Solid-state chemistry |
One of the issues faced by drug delivery is the solubility of the drug in the body; around
40% of newly detected chemicals found in drug discovery are poorly soluble in water. This low solubility affects the bioavailability of the drug, meaning the rate at which the drug reaches the circulatory system and thus the target site. Low bioavailability is most commonly seen in oral administration, which is the preferred choice for drug administration due to its convenience, low costs, and good patient practice. A measure to improve poor bioavailability is to inject the drugs in a solvent mixture with a solubilizing agent. However, results show this solution is ineffective, with the solubilizing agent demonstrating side-effects and/or toxicity.
Nanocrystals used for drug delivery can increase saturation solubility and dispersion velocity. Generally, saturation solubility is thought to be a function of temperature, but it is also based on other factors, such as crystalline structure and particle size, in regards to nanocrystals. The Ostwald-Freundlich equation below shows this relationship:
Where C is the saturation solubility of the nanocrystal, C is the solubility of the drug at a non-nano scale, σ is the interfacial tension of the substance, V is the molar volume of the particle, R is the gas constant, T is the absolute temperature, 𝜌 is the density of the solid, and r is the radius. The advantage of nanocrystals is that they can improve oral adsorption, bioavailability, action onset and reduces intersubject variability.
Consequently, nanocrystals are now being produced and are on the market for a variety of purposes ranging from antidepressants to appetite stimulants. Nanocrystals can be produced using two different ways: the top-down method or the bottom-up method. Bottom-up technologies are also known as nanoprecipitation. This technique involves dissolving a drug in a suitable solvent and then precipitating it with a non-solvent. On the other hand, top-down technologies use force to reduce the size of a particle to nanometers, usually done by milling a drug. Top-down methods are preferred when working with poorly soluble drugs. | 0 | Colloidal Chemistry |
Emma Kendrick is Professor of Energy Materials at the University of Birmingham where her work is focused on new materials for batteries and fuel cells. She is a Fellow of the Royal Society of Chemistry and Institute of Materials, Minerals and Mining. | 1 | Solid-state chemistry |
Klaus Bechgaard did research at the University of Copenhagen, where he also held a Professorship in organic chemistry until 1993. From 1993 until 2000 he was the chairman of the Department of Physics and Chemistry at Risø and in 2001 he was appointed head of the newly assigned Department of Polymer Research at Risø. From 2001 and onwards he was the head of Risø's nano technology programme, and The Danish Center of Polymers which is a joint venture between the Technical University of Copenhagen and Risø.
Bechgaard also conducted research in the field of polymers and nano technology at the University of Copenhagen. | 1 | Solid-state chemistry |
Saiful was born in 1963 in Karachi, Pakistan to ethnically Bengali parents. The family moved to London in 1964 and he grew up in Crouch End, north London. There he went to Stationers Companys School, a state comprehensive. He received both a BSc degree in chemistry and a PhD (1988) from University College London, where he studied under Professor Richard Catlow. Subsequently, he held a postdoctoral fellowship at the Eastman Kodak laboratories in Rochester, New York, working on oxide superconductors. | 1 | Solid-state chemistry |
Long-term inhalation of NiO is damaging to the lungs, causing lesions and in some cases cancer.
The calculated half-life of dissolution of NiO in the blood is more than 90 days. NiO has a long retention half-time in the lungs; after administration to rodents, it persisted in the lungs for more than 3 months. Nickel oxide is classified as a human carcinogen based on increased respiratory cancer risks observed in epidemiological studies of sulfidic ore refinery workers.
In a 2-year National Toxicology Program green NiO inhalation study, some evidence of carcinogenicity in F344/N rats but equivocal evidence in female B6C3F1 mice was observed; there was no evidence of carcinogenicity in male B6C3F1 mice. Chronic inflammation without fibrosis was observed in the 2-year studies. | 1 | Solid-state chemistry |
Since the end of the repository for radioactive waste Morsleben in 1998, the salt dome stability deteriorated to a state where it could collapse. Since 2003, a volume of m of salt-concrete has been pumped into the pit to temporarily stabilize the upper levels. In addition another m of salt-concrete will be used to temporarily stabilize the lower levels. | 1 | Solid-state chemistry |
One class of inorganic molecular wires consist of subunits related to Chevrel clusters. The synthesis of MoSI was performed in sealed and vacuumed quartz ampoule at 1343 K. In MoSI, the repeat units are MoSI clusters, which are joined together by flexible sulfur or iodine bridges.
Chains can also be produced from metallo-organic precursors. | 1 | Solid-state chemistry |
Freeze-casting is a directional solidification technique that is utilized to fabricate materials exhibiting anisotropic, elongated pore structures. Pore morphology is defined, in large part, by the morphology of the solidified fluid.
Titanium foams exhibiting dendritic and lamellar pore structures have been produced, through the use of non-aqueous and aqueous processing respectively. These materials exhibit anisotropic mechanical properties as a result of their anisotropic pore structures. Compressive strength for loads applied parallel to the wall direction of titanium foams are found to be, on average, 2.5 times greater than for those applied perpendicular to the wall direction. | 0 | Colloidal Chemistry |
Allomerism is the similarity in the crystalline structure of substances of different chemical composition. | 1 | Solid-state chemistry |
Mircea Dincă (born 1980) is a Romanian-American inorganic chemist. He is a Professor of Chemistry and W. M. Keck Professor of Energy at the Massachusetts Institute of Technology (MIT). At MIT, Dincă leads a research group that focuses on the synthesis of functional metal-organic frameworks (MOFs), which possess conductive, catalytic, and other material-favorable properties. | 1 | Solid-state chemistry |
The mineral bobshannonite, NaKBa(Mn,Na)(Nb,Ti)(SiO)O(OH)(O,F), was named in his honor in recognition of his major contributions to the field of crystal chemistry in particular and mineralogy in general through his development of accurate and comprehensive ionic radii and his work on dielectric properties of minerals. | 1 | Solid-state chemistry |
Polyvinylcarbazole was discovered by the chemists Walter Reppe (1892-1969), Ernst Keyssner and Eugen Dorrer and patented by I.G. Farben in the USA in 1937. PVC was the first polymer whose photoconductivity was known. Starting in the 1960s, further polymers of this kind were sought. | 1 | Solid-state chemistry |
Consider two-level systems at different positions in space.
Maxwell's equations lead to a coupling among all the optical resonances since the field emitted from a specific resonance interferes with the emitted fields of all other resonances.
As a result, the system is characterized by eigenmodes originating from the radiatively coupled optical resonances.
A spectacular situation arises if identical two-level systems are regularly arranged with distances that equals an integer multiple of , where is the optical wavelength.
In this case, the emitted fields of all resonances interfere constructively and the system behaves effectively as a single system with a -times stronger optical polarization.
Since the intensity of the emitted electromagnetic field is proportional to the squared modulus of the polarization, it scales initially as .
Due to the cooperativity that originates from the coherent coupling of the subsystems, the radiative decay rate is increased by , i.e., where is the radiative decay of a single two-level system.
Thus the coherent optical polarization decays -times faster proportional to than that of an isolated system.
As a result, the time integrated emitted field intensity scales as , since the initial factor is multiplied by which arises from the time integral over the enhanced radiative decay.
This effect of superradiance has been demonstrated by monitoring the decay of the exciton polarization in suitably arranged semiconductor multiple quantum wells.
Due to superradiance introduced by the coherent radiative coupling among the quantum wells, the decay rate increases proportional to the number of quantum wells and is thus significantly more rapid than for a single quantum well.
The theoretical analysis of this phenomenon requires a consistent solution of Maxwell's equations together with the SBEs. | 1 | Solid-state chemistry |
Aurivillius received his basic scientific education at the then Stockholm University where he graduated in 1937 and earned a fil. lic. in 1943. By 1949, he had made some important discoveries about the oxidation of mixed metals, which became quite prominent in the world of chemistry. He completed his dissertation, "X-ray Examinations of Bismuth Oxifluoride and Mixed Oxides with Trivalent Bismuth", at Stockholm University in 1951. Aurivillius joined the Swedish National Defence Research Institute in 1952, where he worked first as a research engineer and later senior researcher. By 1960, Aurivillius was a docent of physical chemistry and acting senior lecturer at the Stockholm University. In 1965, he was appointed professor of inorganic chemistry at Lund University, a professorship he held until 1983. During the sixties, he worked in the field of crystallography alongside his wife, Karin Aurivillius. | 1 | Solid-state chemistry |
The cost of surfactants is partially dependent on the crude oil market. As a stock ingredient for production of surfactants, paints highly dependent on surfactants will be affected by this market. More intricate surfactants with larger, more difficult to synthesize structure are more expensive to produce and have a greater effect on end market price of their applications. As a result, simple, easy to produce and more environmentally friendly surfactants are used more widely. | 0 | Colloidal Chemistry |
Salts are characteristically insulators. Although they contain charged atoms or clusters, these materials do not typically conduct electricity to any significant extent when the substance is solid. In order to conduct, the charged particles must be mobile rather than stationary in a crystal lattice. This is achieved to some degree at high temperatures when the defect concentration increases the ionic mobility and solid state ionic conductivity is observed. When the ionic compounds are dissolved in a liquid or are melted into a liquid, they can conduct electricity because the ions become completely mobile. For this reason, liquified (molten) salts and solutions containing dissolved salts (e.g., sodium chloride in water) can be used as electrolytes. This conductivity gain upon dissolving or melting is sometimes used as a defining characteristic of ionic compounds.
In some unusual ionic compounds: fast ion conductors, and ionic glasses, one or more of the ionic components has a significant mobility, allowing conductivity even while the material as a whole remains solid. This is often highly temperature dependent, and may be the result of either a phase change or a high defect concentration. These materials are used in all solid-state supercapacitors, batteries, and fuel cells, and in various kinds of chemical sensors. | 1 | Solid-state chemistry |
Whittingham conceived the intercalation electrode. Exxon manufactured Whittingham's lithium-ion battery in the 1970s, based on a titanium disulfide cathode and a lithium-aluminum anode. The battery had high energy density and the diffusion of lithium ions into the titanium disulfide cathode was reversible, making the battery rechargeable. In addition, titanium disulfide has a particularly fast rate of lithium ion diffusion into the crystal lattice. Exxon threw its resources behind the commercialization of a Li/LiClO/ TiS battery. However, safety concerns led Exxon to end the project. Whittingham and his team continued to publish their work in academic journals of electrochemistry and solid-state physics. He left Exxon in 1984 and spent four years at Schlumberger as a manager. In 1988, he became Professor at the Chemistry Department, Binghamton University, U.S. to pursue his academic interests.
"All these batteries are called intercalation batteries. It’s like putting jam in a sandwich. In the chemical terms, it means you have a crystal structure, and we can put lithium ions in, take them out, and the structure’s exactly the same afterwards," Whittingham said. "We retain the crystal structure. That’s what makes these lithium batteries so good, allows them to cycle for so long."
Lithium batteries have limited capacity because less than one lithium-ion/electron is reversibly intercalated per transition metal redox center. To achieve higher energy densities, one approach is to go beyond the one-electron redox intercalation reactions. Whittingham's research has advanced to multi-electron intercalation reactions, which can increase the storage capacity by intercalating multiple lithium ions. A few multi-electron intercalation materials have been successfully developed by Whittingham, like LiVOPO/VOPO. The multivalent vanadium cation (V) plays an important role to accomplish the multi-electron reactions. These promising materials shine lights on the battery industry to increase energy density rapidly.
Whittingham received the Young Author Award from The Electrochemical Society in 1971, the Battery Research Award in 2003, and was elected a Fellow in 2004. In 2010, he was listed as one of the Top 40 innovators for contributions to advancing green technology by Greentech Media. In 2012, Whittingham received the IBA Yeager Award for Lifetime Contribution to Lithium Battery Materials Research, and he was elected a Fellow of Materials Research Society in 2013. He was listed along with John B. Goodenough, for pioneering research leading to the development of the lithium-ion battery on a list of Clarivate Citation Laureates for the Nobel Prize in Chemistry by Thomson Reuters in 2015. In 2018, Whittingham was elected to the National Academy of Engineering, "for pioneering the application of intercalation chemistry for energy storage materials."
In 2019, Whittingham, along with John B. Goodenough and Akira Yoshino, was awarded the 2019 Nobel Prize in Chemistry "for the development of lithium-ion batteries." | 1 | Solid-state chemistry |
Chemical vapour transport results in very pure materials. The reaction typically occurs in a sealed ampoule. A transporting agent, added to the sealed ampoule, produces a volatile intermediate species from the solid reactant. For metal oxides, the transporting agent is usually Cl or HCl. The ampoule has a temperature gradient, and, as the gaseous reactant travels along the gradient, it eventually deposits as a crystal. An example of an industrially-used chemical vapor transport reaction is the Mond process. The Mond process involves heating impure nickel in a stream of carbon monoxide to produce pure nickel. | 1 | Solid-state chemistry |
The hydrophilic–lipophilic balance (HLB) of a surfactant is a measure of its degree of hydrophilicity or lipophilicity, determined by calculating percentages of molecular weights for the hydrophilic and lipophilic portions of the surfactant molecule, as described by Griffin in 1949 and 1954. Other methods have been suggested, notably in 1957 by Davies. | 0 | Colloidal Chemistry |
ProteaseMAX'is the brandname of Promega for sodium 3-((1-(furan-2-yl)undecyloxy)carbonylamino)propane-1-sulfonate. This cleavable detergent is sensitive to heat and acid and is degraded during a typical trypsin digestion into the uncharged lipophilic compound 1-(furan-2-yl)undecan-1-ol and the zwitterionic 3-aminopropane-1-sulfonic acid (homotaurine), which can be removed by C18 solid phase extraction during sample work-up. | 0 | Colloidal Chemistry |
On their introduction in the 1940s, PFASs were considered inert. Early occupational studies revealed elevated levels of fluorochemicals, including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA, C8), in the blood of exposed industrial workers, but cited no ill health effects. These results were consistent with the measured serum concentrations of PFOS and PFOA in 3M plant workers ranging from 0.04 to 10.06 ppm and 0.01 to 12.70 ppm, respectively, well below toxic and carcinogenic levels cited in animal studies. Given, however, the "forever chemical" property of PFASs (serum elimination half-life of 4–5 years) and widespread environmental contamination, molecules have been shown to accumulate in humans to such a degree that adverse health outcomes have resulted.
Hormone-disrupting chemicals, including PFASs, are linked with rapid declines in human fertility. In a meta-analysis for associations between PFASs and human clinical biomarkers for liver injury, authors considered both PFAS effects on liver biomarkers and histological data from rodent experimental studies and concluded that evidence exists showing that PFOA, perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) are hepatotoxic to humans.
Many comprehensive epidemiological studies linking adverse human health effects to PFASs, particularly PFOA, come from the C8 Science Panel. The panel was formed as part of a contingency to a class action lawsuit brought by communities in the Ohio River Valley against DuPont in response to landfill and wastewater dumping of PFAS-laden material from DuPonts West Virginia Washington Works Plant. The panel measured PFOA (also known as C8) serum concentrations in 69,000 individuals from around DuPonts Washington Works Plant and found a mean concentration of 83.0 ng/mL, compared to 4 ng/mL in a standard population of Americans. This panel reported probable links between elevated PFOA blood concentration and hypercholesterolemia, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer as well as pregnancy-induced hypertension and preeclampsia. | 0 | Colloidal Chemistry |
PtSi is a semiconductor and a Schottky barrier with high stability and good sensitivity, and can be used in infrared detection, thermal imaging, or ohmic and Schottky contacts. Platinum silicide was most widely studied and used in the 1980s and 90s, but has become less commonly used, due to its low quantum efficiency. PtSi is now most commonly used in infrared detectors, due to the large size of wavelengths it can be used to detect. It has also been used in detectors for infrared astronomy. It can operate with good stability up to 0.05 °C. Platinum silicide offers high uniformity of arrays imaged. The low cost and stability makes it suited for preventative maintenance and scientific infrared imaging. | 1 | Solid-state chemistry |
When the constituent components of silicone foam are mixed together, they evolve hydrogen gas, which causes bubbles to form within the rubber, as it changes from liquid to solid. This results in an outward pressure. Temperature and humidity can influence the rate of expansion. | 0 | Colloidal Chemistry |
Small-angle laser light scattering has provided information about spatial density fluctuations or the shape of growing crystal grains. In addition, confocal laser scanning microscopy has been used to observe crystal growth near a glass surface. Electro-optic shear waves have been induced by an ac pulse, and monitored by reflection spectroscopy as well as light scattering. Kinetics of colloidal crystallization have been measured quantitatively, with nucleation rates being depending on the suspension concentration. Similarly, crystal growth rates have been shown to decrease linearly with increasing reciprocal concentration. | 0 | Colloidal Chemistry |
Besides making pioneering contribution in the domain of Soil Science, Dr Mukherjee played a key role in the development of agricultural research and education in the country. Soon after his appointment as Director of the Imperial (now Indian Agricultural Research Institute, New Delhi), in 1945, Dr Mukherjee began to
reorganise the research and educational activities of the Institute in the country as a whole. Under his direction the Institute expanded considerably in terms
of its academic activities and scientific performance. He initiated research in the area of soil-plant studies. Some of the sections he created in the Division of Soil Science and Agricultural Chemistry are Soil Survey, Soil Physics, Agricultural Chemistry, Soil Fertility, Soil Microbiology, Biochemistry, Organic Chemistry and Spectroscopy. Recent expansion of some of the sections such as Soil Survey, Microbiology, Biochemistry, Agricultural Chemicals, Agricultural Physics were credited to him.
The credit for initiating systematic studies on micronutrient elements in soils and plants and also on clay mineralogy of soils with the help of sophisticated instruments and modern techniques goes to him. He initiated work in the Institute on the nutritive value of foods, feeds and fodders, on insecticides and fungicides, and on the chemistry of plant products.
He was the first in the country to lay great emphasis on the importance of soil surveys for agricultural development and underlined the importance of uniformity in the methods of survey, classification and nomenclature of the soils of India. At his suggestion the Ministry of Agriculture, Government of India established in 1949 the Central Committee on Soil Science with him as chairman. The terms and reference of the Committee were practically in conformity with the objectives of the All India Soil and Land Use Survey Organization established in 1956 with 4 regional centres.
The soil map of India revised under his guidance (scale 1" --- 70 miles) showing 20 soil classes was published in 1954. He also developed the concept of the
basic soil regions in the classifications of the soils of India based on similar characteristics of land viz.., the climate, topography, vegetation and soils. | 0 | Colloidal Chemistry |
Akhoury Purnendu Bhusan Sinha (23 September 1928 – 4 July 2021) was an Indian solid state chemist who was the head of the Physical Chemistry Division of the National Chemical Laboratory, Pune. He is known for his theories on semiconductors and his studies on synthesis of manganites. He was an elected fellow of the Indian National Science Academy and the Indian Academy of Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded Sinha the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, in 1972, for his contributions to chemical sciences. | 1 | Solid-state chemistry |
Potash ( ) includes various mined and manufactured salts that contain potassium in water-soluble form. The name derives from pot ash, plant ashes or wood ash soaked in water in a pot, the primary means of manufacturing potash before the Industrial Era. The word potassium is derived from potash.
Potash is produced worldwide in amounts exceeding 71.9 million tonnes (~45.4 million tonnes KO equivalent) per year as of 2021, with Canada being the largest producer, mostly for use in fertilizer. Various kinds of fertilizer-potash constitute the single greatest industrial use of the element potassium in the world. Potassium was first derived in 1807 by electrolysis of caustic potash (potassium hydroxide). | 1 | Solid-state chemistry |
Particle deposition is the spontaneous attachment of particles to surfaces. The particles in question are normally colloidal particles, while the surfaces involved may be planar, curved, or may represent particles much larger in size than the depositing ones (e.g., sand grains). Deposition processes may be triggered by appropriate hydrodynamic flow conditions and favorable particle-surface interactions. Depositing particles may just form a monolayer which further inhibits additional particle deposition, and thereby one refers to surface blocking. Initially attached particles may also serve as seeds for further particle deposition, which leads to the formation of thicker particle deposits, and this process is termed as surface ripening or fouling. While deposition processes are normally irreversible, initially deposited particles may also detach. The latter process is known as particle release and is often triggered by the addition of appropriate chemicals or a modification in flow conditions.
Microorganisms may deposit to surfaces in a similar fashion as colloidal particles. When macromolecules, such as proteins, polymers or polyelectrolytes attach to surfaces, one rather calls this process adsorption. While adsorption of macromolecules largely resembles particle deposition, macromolecules may substantially deform during adsorption. The present article mainly deals with particle deposition from liquids, but similar process occurs when aerosols or dust deposit from the gas phase. | 0 | Colloidal Chemistry |
The band gap of uranium dioxide is comparable to those of silicon and gallium arsenide, near the optimum for efficiency vs band gap curve for absorption of solar radiation, suggesting its possible use for very efficient solar cells based on Schottky diode structure; it also absorbs at five different wavelengths, including infrared, further enhancing its efficiency. Its intrinsic conductivity at room temperature is about the same as of single crystal silicon.
The dielectric constant of uranium dioxide is about 22, which is almost twice as high as of silicon (11.2) and GaAs (14.1). This is an advantage over Si and GaAs in the construction of integrated circuits, as it may allow higher density integration with higher breakdown voltages and with lower susceptibility to the CMOS tunnelling breakdown.
The Seebeck coefficient of uranium dioxide at room temperature is about 750 µV/K, a value significantly higher than the 270 µV/K of thallium tin telluride (TlSnTe) and thallium germanium telluride (TlGeTe) and of bismuth-tellurium alloys, other materials promising for thermoelectric power generation applications and Peltier elements.
The radioactive decay impact of the U and U on its semiconducting properties was not measured . Due to the slow decay rate of these isotopes, it should not meaningfully influence the properties of uranium dioxide solar cells and thermoelectric devices, but it may become an important factor for VLSI chips. Use of depleted uranium oxide is necessary for this reason. The capture of alpha particles emitted during radioactive decay as helium atoms in the crystal lattice may also cause gradual long-term changes in its properties.
The stoichiometry of the material dramatically influences its electrical properties. For example, the electrical conductivity of UO is orders of magnitude lower at higher temperatures than the conductivity of UO.
Uranium dioxide, like UO, is a ceramic material capable of withstanding high temperatures (about 2300 °C, in comparison with at most 200 °C for silicon or GaAs), making it suitable for high-temperature applications like thermophotovoltaic devices.
Uranium dioxide is also resistant to radiation damage, making it useful for rad-hard devices for special military and aerospace applications.
A Schottky diode of UO and a p-n-p transistor of UO were successfully manufactured in a laboratory. | 1 | Solid-state chemistry |
When used as an ingredient in food, antifoaming agents are intended to curb effusion or effervescence in preparation or serving. The agents are included in a variety of foods and in materials for food preparation; McDonald's includes polydimethylsiloxane (a type of silicone) in its oil to mitigate hazardous splashes of oil caused by foaming in fryers, so it has been listed as an ingredient in their chicken nuggets, french fries, and other fried menu items. | 0 | Colloidal Chemistry |
Kerker was born on September 25, 1920, in Utica, New York. He received his A.B. in chemistry from Columbia University in 1941. From 1942 to 1945, he was a member of United States Army and received Bronze Star Medal for his service. He married his wife, Reva Stemerman, in 1946. Graduating from Columbia University with a PhD in chemistry in 1949, he joined Clarkson University as a professor in the same year. He acted as the chair of the department of chemistry from 1960 to 1964, as well as the dean of science from 1964 to 1966 and from 1981 to 1985. He retired from Clarkson University in 1991. Serving as the editor of Journal of Colloid and Interface Science from 1965 to 1992, he was also granted fellowships by Optical Society, American Chemical Society and Ford Foundation. Kerker died on May 2, 2016, in Thousand Oaks, California, U.S., and was survived by his wife and four children. He was a contributor to Midstream magazine and Jewish Theological Seminary of America, as well as Isis journal.
Kerkers work encompassed aerosol and colloid science, as well as their relation to light scattering by small particles. He is known for authoring the 1969 textbook on the subject, The Scattering of Light and Other Electromagnetic Radiation'. Regarded as a pioneer of surface-enhanced Raman spectroscopy (SERS), he has worked on the mathematical models in the field. In 1986, Kerker also coauthored the article on light scattering by hypothetical magnetic spheres, which hypothesized a distinct absence of backscattering for small particles with equal relative permittivities and permeabilities. While being largely unnoticed at the time of its publication, the work has since attracted attention with the advent of metamaterials and nanophotonics; the associated phenomenon, named as Kerker effect, was later verified experimentally. | 0 | Colloidal Chemistry |
For settling particles that are considered individually, i.e. dilute particle solutions, there are two main forces enacting upon any particle. The primary force is an applied force, such as gravity, and a drag force that is due to the motion of the particle through the fluid. The applied force is usually not affected by the particle's velocity, whereas the drag force is a function of the particle velocity.
For a particle at rest no drag force will be exhibited, which causes the particle to accelerate due to the applied force. When the particle accelerates, the drag force acts in the direction opposite to the particles motion, retarding further acceleration, in the absence of other forces drag directly opposes the applied force. As the particle increases in velocity eventually the drag force and the applied force will approximately equate, causing no further change in the particles velocity. This velocity is known as the terminal velocity, settling velocity or fall velocity of the particle. This is readily measurable by examining the rate of fall of individual particles.
The terminal velocity of the particle is affected by many parameters, i.e. anything that will alter the particle's drag. Hence the terminal velocity is most notably dependent upon grain size, the shape (roundness and sphericity) and density of the grains, as well as to the viscosity and density of the fluid. | 0 | Colloidal Chemistry |
It is said to have potential for optical applications but the exploitation of this potential has been limited by the ability to readily grow single crystals Gallium selenide crystals show great promise as a nonlinear optical material and as a photoconductor. Non-linear optical materials are used in the frequency conversion of laser light. Frequency conversion involves the shifting of the wavelength of a monochromatic source of light, usually laser light, to a higher or lower wavelength of light that cannot be produced from a conventional laser source.
Several methods of frequency conversion using non-linear optical materials exist. Second harmonic generation leads to doubling of the frequency of infrared carbon dioxide lasers. In optical parametric generation, the wavelength of light is doubled. Near-infrared solid-state lasers are usually used in optical parametric generations.
One original problem with using gallium selenide in optics is that it is easily broken along cleavage lines and thus it can be hard to cut for practical application. It has been found, however, that doping the crystals with indium greatly enhances their structural strength and makes their application much more practical. There remain, however, difficulties with crystal growth that must be overcome before gallium selenide crystals may become more widely used in optics.
Single layers of gallium selenide are dynamically stable two-dimensional semiconductors, in which the valence band has an inverted Mexican-hat shape, leading to a Lifshitz transition as the hole-doping is increased.
The integration of gallium selenide into electronic devices has been hindered by its air sensitivity. Several approaches have been developed to encapsulate GaSe mono- and few-layers, leading to improved chemical stability and electronic mobility. | 1 | Solid-state chemistry |
Czarnik joined the Chemistry Department at the Ohio State University as assistant professor in 1983. He later was promoted to associate professor. Czarnik worked at Ohio State University until 1993, when he was offered a position as Director of the Bio-Organic Chemistry group at Parke-Davis Research Laboratory in Ann Arbor, Michigan. Czarnik was the founding editor of ACS Combinatorial Science (formerly Journal of Combinatorial Chemistry), an academic journal published by the American Chemical Society.
In April 1998, Czarnik co-founded Illumina, Inc., a biotechnology company now traded on NASDAQ and specializing in sequencing, genotyping and gene expression, with David Walt, John Stuelpnagel, Larry Bock, and Mark Chee. Czarnik served as Illuminas chief scientific officer (CSO) until 2000. He was terminated from his position of CSO and later filed a wrongful termination lawsuit. The Court ruled in Czarniks favor, but the company appealed. The appeal court sustained the lower court verdict but in 2005 reduced the punitive damage ordered by the jury. Czarnik later filed a patent law case in the United States District Court for the District of Delaware, alleging four counts against his former employer, including reputational harm for correction of named inventor under 35 U.S.C. § 256.
In 2001, Czarnik was recruited by Sensors for Medicine and Science, Inc., where he served as chief scientific officer. Since 2003, Czarnik has co-founded a number of biotechnology companies including Deuteria Pharmaceuticals LLC and Protia LLC.
Czarnik is a founder of RenoCares, a charity that provides support to alcohol and drug addicts convicted of misdemeanors in the form of financial aid for rehabilitation treatment, counseling, and psychological services. The organization is managed by the Community Foundation of Western Nevada. Since 2016, annual Czarnik Awards are given for exceptional work in the area of chemosensors at the International Conference on Molecular Sensors and Molecular Logic Gates (MSMLG). In 2007, Czarnik took part as an executive producer of Electric Heart: Don Ellis, a documentary about Don Ellis, an American jazz musician. | 1 | Solid-state chemistry |
The high surface area of a material in nanoparticle form allows heat, molecules, and ions to diffuse into or out of the particles at very large rates. The small particle diameter, on the other hand, allows the whole material to reach homogeneous equilibrium with respect to diffusion in a very short time. Thus many processes that depend on diffusion, such as sintering can take place at lower temperatures and over shorter time scales inducing catalysis. | 0 | Colloidal Chemistry |
Iron pyrite is unstable when exposed to the oxidizing conditions prevailing at the Earths surface: iron pyrite in contact with atmospheric oxygen and water, or damp, ultimately decomposes into iron oxyhydroxides (ferrihydrite, FeO(OH)) and sulfuric acid (). This process is accelerated by the action of Acidithiobacillus' bacteria which oxidize pyrite to first produce ferrous ions (), sulfate ions (), and release protons (, or ). In a second step, the ferrous ions () are oxidized by into ferric ions () which hydrolyze also releasing ions and producing FeO(OH). These oxidation reactions occur more rapidly when pyrite is finely dispersed (framboidal crystals initially formed by sulfate reducing bacteria (SRB) in argillaceous sediments or dust from mining operations). | 1 | Solid-state chemistry |
Vanadium(II) oxide is the inorganic compound with the idealized formula VO. It is one of the several binary vanadium oxides. It adopts a distorted NaCl structure and contains weak V−V metal to metal bonds. VO is a semiconductor owing to delocalisation of electrons in the t orbitals. VO is a non-stoichiometric compound, its composition varying from VO to VO.
Diatomic VO is one of the molecules found in the spectrum of relatively cool M-type stars. A potential use of vanadium(II) monoxide is as a molecular vapor in synthetic chemical reagents in low-temperature matrices. | 1 | Solid-state chemistry |
Nanofluids poses the following advantages as compared to conventional fluids which makes them suitable for use in solar collectors:
*Absorption of solar energy will be maximized with change of the size, shape, material and volume fraction of the nanoparticles.
*The suspended nanoparticles increase the surface area but decrease the heat capacity of the fluid due to the very small particle size.
*The suspended nanoparticles enhance the thermal conductivity which results improvement in efficiency of heat transfer systems.
*Properties of fluid can be changed by varying concentration of nanoparticles.
*Extremely small size of nanoparticles ideally allows them to pass through pumps.
*Nanofluid can be optically selective (high absorption in the solar range and low emittance in the infrared.
The fundamental difference between the conventional and nanofluid-based collector lies in the mode of heating of the working fluid. In the former case the sunlight is absorbed by a surface, where as in the latter case the sunlight is directly absorbed by the working fluid (through radiative transfer). On reaching the receiver the solar radiations transfer energy to the nanofluid via scattering and absorption. | 0 | Colloidal Chemistry |
Some common per- and polyfluoroalkyl substances include:
* Polytetrafluoroethylene (aka PTFE or Teflon)
* Perfluoroalkyl carboxylic acids (PFCAs)
* Perfluorosulfonic acids (PFSAs)
* Fluorotelomers (FTOHs) | 0 | Colloidal Chemistry |
Liposomes are spherical vesicles composed of synthetic or natural phospholipids that self-assemble in aqueous solution in sizes ranging from tens of nanometers to micrometers. The resulting vesicle, which has an aqueous core surrounded by a hydrophobic membrane, can be loaded with a wide variety of hydrophobic or hydrophilic molecules for therapeutic purposes.
Liposomes are typically synthesized with naturally occurring phospholipids, mainly phosphatidylcholine. Cholesterol is often included in the formulation to adjust the rigidity of the membrane and to increase stability. The molecular cargo is loaded through liposome formation in aqueous solution, solvent exchange mechanisms, or pH gradients methods. Various molecules can also be chemically conjugated to the surface of the liposome to alter recognition properties. One typical modification is conjugating polyethyleneglycol (PEG) to the vesicle surface. The hydrophilic polymer prevents recognition by macrophages and decreases clearance. The size, surface charge, and bilayer fluidity also alter liposome delivery kinetics.
Liposomes diffuse from the bloodstream into the interstitial space near the target site. As the cell membrane itself is composed of phospholipids, liposomes can directly fuse with the membrane and release the cargo into the cytosol, or may enter the cell through phagocytosis or other active transport pathways.
Liposomal delivery has various advantages. Liposomes increase the solubility, stability, and uptake of drug molecules. Peptides, polymers, and other molecules can be conjugated to the surface of a liposome for targeted delivery. Conjugating various ligands can facilitate binding to target cells based on the receptor-ligand interaction. Altering vesicle size and surface chemistry can also be tuned to increase circulation time.
Various FDA-approved liposomal drugs are in clinical use in the US. The anthracycline drug doxorubicin is delivered with phospholipid-cholesterol liposomes to treat AIDS-related Kaposi sarcoma and multiple myeloma with high efficacy and low toxicity. Many others are undergoing clinical trials, and liposomal drug delivery remains an active field of research today, with potential applications including nucleic acid therapy, brain targeting, and tumor therapy. | 0 | Colloidal Chemistry |
Closed-cell metal foam was first reported in 1926 by Meller in a French patent where foaming of light metals, either by inert gas injection or by blowing agent, was suggested. Two patents on sponge-like metal were issued to Benjamin Sosnik in 1948 and 1951 who applied mercury vapor to blow liquid aluminium.
Closed-cell metal foams were developed in 1956 by John C. Elliott at Bjorksten Research Laboratories. Although the first prototypes were available in the 1950s, commercial production began in the 1990s by Shinko Wire company in Japan. Closed-cell metal foams are primarily used as an impact-absorbing material, similarly to the polymer foams in a bicycle helmet but for higher impact loads. Unlike many polymer foams, metal foams remain deformed after impact and can therefore only be deformed once. They are light (typically 10–25% of the density of an identical non-porous alloy; commonly those of aluminium) and stiff and are frequently proposed as a lightweight structural material. However, they have not been widely used for this purpose.
Closed-cell foams retain the fire resistance and recycling potential of other metal foams, but add the property of flotation in water. | 0 | Colloidal Chemistry |
Because the clay layer is typically covered with topsoil, a location which is vulnerable to a quick clay landslide is usually identifiable only by soil testing, and is rarely obvious to a casual observer. Thus human settlements and transportation links have often been built on or near clay deposits, resulting in a number of notable catastrophes:
* In 1702, a landslide destroyed almost all traces of the medieval town Sarpsborg in the Østfold county in Norway. 15 people and 200 animals were killed.
* On 19 May 1893, a landslide in Verdal, Norway, killed 116 people and destroyed 105 farms. It left a crater several kilometers in diameter.
* The most disastrous such landslide to affect North America occurred in 1908, when a slide into the frozen Du Lièvre River propelled a wave of ice-filled water into Notre-Dame-de-la-Salette, Quebec, causing the loss of 33 lives and the destruction of 12 homes.
* In 1955, a landslide affected part of the downtown of Nicolet, Quebec, causing $10 million in damages.
*In 1957, a large quick-clay landslide occurred in Lilla Edet, by the Göta River, in southwestern Sweden. A large part of a factory slid into the river, causing a thirty meter reduction in the river width. The earth mass coming into the river produced an approximately six meter high wave.
*On March 27, 1964, parts of Anchorage, Alaska built on sandy bluffs overlying "Bootlegger Cove clay" near Cook Inlet, most notably the Turnagain neighborhood, suffered landslide damage during the 1964 Alaska Earthquake. The neighborhood lost 75 houses in the landslide, and the destroyed area has since been turned into Earthquake Park.
* On 4 May 1971, 31 lives were lost when 40 homes were swallowed in a retrogressive flowslide in Saint-Jean-Vianney, Quebec, resulting in the relocation of the entire town when the government declared the area uninhabitable due to the presence of Leda clay. The event at Saint-Jean-Vianney contributed to the abandonment of the town of Lemieux, Ontario, in 1991, after a 1989 study showed it was also located on the same type of clay along the South Nation River. In 1993, those findings were borne out when the town's abandoned main street was swallowed by a massive 17-hectare landslide.
* On November 30, 1977, the Tuve landslide in western Sweden killed 9 people and destroyed 67 houses.
* Another famous flow of quick clay at Rissa, Norway, in 1978 caused about 33 hectares (82 acres) of farmland to liquefy and flow into the lake Botn over a few hours, with the loss of one life. The Rissa slide was well recorded by local citizens and a documentary film was made about it in 1981.
* On 11 May 2010, quick clay took the lives of a family living in Saint-Jude, Quebec, when the land their house was built on suddenly tumbled down toward the Salvail River. The landslide was so sudden that the family members died where they sat; they had been watching an ice hockey game on television. The slide took out a portion of rural road which took a year to reinstate.
* On 2 February 2015, a landslide collapsed a pillar on the Skjeggestad Bridge in South-East Norway. The landslide was caused by nearby earthworks.
* On 3 June 2020, eight buildings were swept into the sea by a landslide in Kråkneset in the Alta municipality in Norway. The landslide was filmed by a resident. There were no casualties, and a dog was rescued from the sea.
* On 30 December 2020, part of a housing area was swept away by a landslide in Ask in the Gjerdrum municipality in Norway, 25 km (15 miles) north-east of the capital Oslo. The 300 m × 700 m (985 ft × 2300 ft) quick clay landslide wrecked several houses and killed 10 people.
*On 23 September 2023, near the town of Stenungsund, Sweden, an area of was affected by a quick clay landslide, which among other things damaged the E6 motorway between Gothenburg and Oslo.
These landslides are retrogressive, meaning they usually start at water, and progress upwards at slow walking speed, although particularly deep quick clay layers on sloped regions may collapse much more rapidly, or in very large chunks that can slide at great speed due to the liquid nature of the disturbed clay. They have been known to penetrate kilometers inland, and consume everything in their path.
In modern times, areas known to have quick clay deposits are commonly tested in advance of any major human development. It is not always possible to entirely avoid building on a quick clay site, although modern engineering techniques have found technical precautions which can be taken to mitigate the risk of disaster. For example, when Ontario's Highway 416 had to pass through a quick clay deposit near Nepean, lighter fill materials such as polystyrene were used for the road bed, vertical wick drains were inserted along the route and groundwater cutoff walls were built under the highway to limit water infiltration into the clay. | 0 | Colloidal Chemistry |
Katsumi Kaneko was born in Yokohama (Kanagawa), Japan. He graduated with a Bachelor of Engineering degree in 1969 from Yokohama National University (Applied Chemistry), Yokohama. He received a masters degree in physical chemistry at The University of Tokyo, in 1971. He received Doctor of Science in solid state chemistry in 1978 for submitted thesis from The University of Tokyo, entitled “Electrical Properties and Defect Structures of Iron Hydroxide Oxide'
Colloids”. | 1 | Solid-state chemistry |
Marine waters are those of the ocean, another term for which is euhaline seas. The salinity of euhaline seas is 30 to 35 ‰. Brackish seas or waters have salinity in the range of 0.5 to 29 ‰ and metahaline seas from 36 to 40 ‰. These waters are all regarded as thalassic because their salinity is derived from the ocean and defined as homoiohaline if salinity does not vary much over time (essentially constant). The table on the right, modified from Por (1972), follows the "Venice system" (1959).
In contrast to homoiohaline environments are certain poikilohaline environments (which may also be thalassic) in which the salinity variation is biologically significant. Poikilohaline water salinities may range anywhere from 0.5 to greater than 300 ‰. The important characteristic is that these waters tend to vary in salinity over some biologically meaningful range seasonally or on some other roughly comparable time scale. Put simply, these are bodies of water with quite variable salinity.
Highly saline water, from which salts crystallize (or are about to), is referred to as brine. | 1 | Solid-state chemistry |
Memory foam consists mainly of polyurethane with additional chemicals that increase its viscosity and density. It is often referred to as "viscoelastic" polyurethane foam, or low-resilience polyurethane foam (LRPu). The foam bubbles or ‘cells’ are open, effectively creating a matrix through which air can move. Higher-density memory foam softens in reaction to body heat, allowing it to mold to a warm body in a few minutes. Newer foams may recover their original shape more quickly. | 0 | Colloidal Chemistry |
Since 1997, she has built a unique high temperature calorimetry facility. She has also designed and enhanced the instrumentation. Navrotsky introduced and applied the method for measuring the energetics of crystalline oxides of glasses, amorphous, nanophase material, porous materials of hydrous phases and carbonates also more recently nitrides and oxynitrides. Obtaining the thermo chemical data is used to understand the compatibility and reactivity of materials in technological and geological application. The energetics provides insight into chemical bonding, order-disorder reactions, and phase transitions.
Navrotsky's calorimetry has also been used in providing thermo chemical data for a variety of perovskite-related phases which has major consequences for convection and evolution on a planetary scale.
One of Navrotsky's works has shown that many zeolitic and mesoporous phases have energies only slightly higher than those of their stable dense polymorphs. The energy is associated with the presence or absence of strained bond angles not with the density. | 1 | Solid-state chemistry |
Converting amines into their hydrochlorides is a common way to improve their water solubility, which can be desirable for substances used in medications. The European Pharmacopoeia lists more than 200 hydrochlorides as active ingredients in medications. These hydrochlorides, compared to free bases, may more readily dissolve in the gastrointestinal tract and be absorbed into the bloodstream more quickly. Additionally, many hydrochlorides of amines have a longer shelf-life than their respective free bases.
Amine hydrochlorides represent latent forms of a more reactive free base. In this regard, formation of an amine hydrochloride confers protection. This effect is illustrated by the hydrochlorides of the amino acids. Glycine methyl ester hydrochloride is a shelf-stable salt that can be readily converted to a reactive glycine methyl ester, a compound that is not shelf-stable. | 1 | Solid-state chemistry |
To produce their metallic microlattice, the HRL/UCI/Caltech team first prepared a polymer template using a technique based on self-propagating waveguide formation, though it was noted that other methods can be used to fabricate the template. The process passed UV light through a perforated mask into a reservoir of UV-curable resin. Fiber-optic-like "self-trapping" of the light occurred as the resin cured under each hole in the mask, forming a thin polymer fiber along the path of the light. By using multiple light beams, multiple fibers could then interconnect to form a lattice.
The process was similar to photolithography in that it used a two-dimensional mask to define the starting template structure, but differed in the rate of formation: where stereolithography might take hours to make a full structure, the self-forming waveguide process allowed templates to be formed in 10–100 seconds. In this way, the process enables large free-standing 3D lattice materials to be formed quickly and scalably. The template was then coated with a thin layer of metal by electroless nickel plating, and the template is etched away, leaving a free-standing, periodic porous metallic structure. Nickel was used as the microlattice metal in the original report. Owing to the electrodeposition process, 7% of the material consisted of dissolved phosphorus atoms, and it contained no precipitates. | 0 | Colloidal Chemistry |
In February 2018, 3M settled a lawsuit for $850 million related to contaminated drinking water in Minnesota. | 0 | Colloidal Chemistry |
Researchers have also constructed the CMOS inverter (logic circuit) by combining a phosphorene PMOS transistor with a MoS NMOS transistor, achieving high heterogeneous integration of semiconducting phosphorene crystals as a new channel material for potential electronic applications. In the inverter, the power supply voltage is set to be 1 V. The output voltage shows a clear transition from VDD to 0 within the input voltage range from −10 to −2 V. A maximum gain of ~1.4 is attained. | 1 | Solid-state chemistry |
Although many progresses have been made on the topic since the classical work of Frenkel,
the Poole-Frenkel formula has been spreadly used to interpret several non-ohmic experimental currents observed in dielectrics and also semiconductors.
The debate about the underlying assumptions of the classical Poole-Frenkel model has given life to several improved Poole-Frenkel models.
These hypotheses are presented in the following.
Only electron (single-carrier) conduction is considered, assuming the existence of ohmic contacts capable to refill detrapped electrons at the electrodes, and space charge effects are neglected, supposing that the field is uniform. A revisitation of this latter assumption can be found, for example, in the “theory of space charge limited current enhanced by Frenkel effect” developed by Murgatroyd.
The carriers mobility is assumed to be field-independent. Neglecting every kind of diffusion process for the de-trapped carriers, the pre-exponential factor in the Poole-Frenkel formula is thus proportional to . This depiction would be suitable for the description of the conduction either in dielectrics or semiconductors. However, Poole–Frenkel effect is likely to be observed only in materials characterized by low mobility values, for, in high mobility solids, the re-trapping of carriers would be gradually inhibited by carrier depletion.
Still, different dependences of the pre-exponential factor from the field can be found: assuming that the carriers could be re-trapped, proportionality to or is obtained, depending on the electron retrapping occurring by the nearest neighbouring trap or after a drift. Moreover, a pre-exponential factor proportional to is found to be the result of random diffusion processes, while dependencies on and are found to be the result of hopping and diffusion transport processes respectively.
In the classical Poole-Frenkel theory a Coulombic trap potential is assumed, but steeper potentials belonging to multipolar defects or screened hydrogenic potentials are considered as well.
Regarding the typology of traps, the Poole–Frenkel effect is described to occur for positively charged trap sites, i.e. for traps that are positive when empty and neutral when filled, in order for the electron to experience a Coulombic potential barrier due to the interaction with the positively charged trap. Donors or acceptors sites and electrons in the valence band will also exhibit the Poole–Frenkel effect as well. On the contrary, a neutral trap site, i.e. a site that is neutral when empty and charged (negatively for electrons) when filled, will not exhibit Poole–Frenkel effect.
Among the others, Simmons has proposed an alternative to the classical model with shallow neutral traps and deep donors, capable to exhibit a bulk-limited conduction with a Schottky electric field dependence, even in presence of a Poole-Frenkel conduction mechanism, thus explaining the "anomalous Poole-Frenkel effect" revealed by TaO and SiO films.
Models there exist that consider the presence of both donor and acceptor trap sites, in a situation called compensation of traps.
The model of Yeargan and Taylor, for example, extends the classical Poole-Frenkel theory including diverse degrees of compensations: when only one kind of trap is considered, the slope of the curve in a Poole-Frenkel plot reproduces that obtained from Schottky emission, in spite of the barrier lowering being twice that for Schottky effect; the slope is twice larger in presence of compensation.
As a further assumption a single energy level for the traps is assumed. However, the existence of further donor levels is discussed, even if they are supposed to be entirely filled for every field and temperature regime, and thus to not furnish any conduction carrier (this is equivalent to state that the additional donor levels are placed well below the Fermi level). | 1 | Solid-state chemistry |
In 1987, Rao and his team published a series of four papers, of which three were in the Proceedings of the Indian Academy of Sciences (Chemical Science), Pramana, and Current Science, all published by the Indian Academy of Sciences. A report was submitted to the Society for Scientific Values that the three papers had no mention of the dates of receipt, which were normally explicitly mentioned in those journals. Upon inquiry, it was found that the paper manuscripts were actually received after the date of publication, indicating that they were backdated. The society declared the case as "Use of Wrong Means to Claim Priority."
Rao has been subject of allegations on plagiarism. Rao and Saluru Baba Krupanidhi at the Indian Institute of Science in Bangalore, with their students Basant Chitara and L. S. Panchakarla, published a paper "Infrared photodetectors based on reduced graphene oxide and graphene nanoribbons" in the journal Advanced Materials in 2011. After publication the journal editors found sentences copied verbatim in the introduction and methodology from a paper published in Applied Physics Letters in 2010. According to Nature report, it was Basant Chitara, a PhD student at IISc, who wrote the text. An apology was issued by the authors later in the same journal. Rao said that he did read the manuscript and that it was an oversight on his part as he focused mainly on the results and discussion.
Scientists such as Rahul Siddharthan (Institute of Mathematical Sciences, Chennai), Y.B. Srinivas (Institute of Wood Science and Technology), and D.P. Sengupta (former professor at IISC), agreed that the plagiarised portion has no bearing on the findings, yet Siddharthan opined that the reactions made by Rao and Krupanidhi were overboard. Rao and Krupanidhi publicly blamed Chitara, and denied the publication as not plagiarism. Rao had commented, "This should not be really considered as plagiarism, but an instance of copying of a few sentences in the text." He even extended the blame to Krupanidhi asserting that he had no role in it as it was written by Krupanidhi without his knowledge. His claims were not justified by the fact that he was the senior scientist and corresponding author in that publication.
More allegations of instances of plagiarism in articles co-authored Rao have been reported. Written with S. Venkataprasad Bhat and Krupanidhi, Raos paper in 2010 about the effect of nanoparticles on solar cells in Applied Physics Express contains texts that are very similar to those of a paper by Matheu et al. from Applied Physics Letters in 2008, which it did not even cite. Rao had stated, referring to the 2011 incident, that "[If] I have ever stolen an idea or a result (in) my entire life, (then) hang me." But Raos article contains similar study to and duplicated figures with that of Matheu et al. An article in the Journal of Luminescence in 2011, written with Chitara, Nidhi Lal and Krupanidhi, contains 20 unattributed lines which appear to be copied from articles by Itskos et al. in Nanotechnology (June 2009 issue) and Heliotis et al. in Advanced Materials (January 2006 issue). Another article in Nanotechnology, written also with Chitara and Krupanidhi, uses six lines from the 1995 article by Huang et al. in Applied Physics Letters.
Rao was given a Bharat Ratna by the Government of India in spite of the controversy and was active as a professor at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR). In December 2013, brother and sister Tanaya Thakur, a law student, and Aditya Thakur, a class XII student, filed a public interest litigation in Allahabad High Court, Lucknow Bench, to challenge Rao's Bharat Ratna. They asserted that "a scientist with proven cases of plagiarism shall not be presented the highest civilian award." But the court ruled them out as "filing pleas for publicity." There was another plea to revoke the award in 2015, but the Central Information Commission dismissed the petition.
On 17 November 2013, at a press conference following the announcement of his Bharat Ratna, he called the Indian politicians "idiots" which caused a national outrage. He said, "Why the hell have these idiots [politicians] given so little to us despite what we have done? For the money that the government has given us we [scientists] have done much more." In his defence Rao insisted that he merely talked about the "idiotic" way the politicians ignore investments for research funding in science. | 1 | Solid-state chemistry |
Most atoms in a nanocluster are surface atoms. Thus, it is expected that the magnetic moment of an atom in a cluster will be larger than that of one in a bulk material. Lower coordination, lower dimensionality, and increasing interatomic distance in metal clusters contribute to enhancement of the magnetic moment in nanoclusters. Metal nanoclusters also show change in magnetic properties. For example, vanadium and rhodium are paramagnetic in bulk but become ferromagnetic in nanoclusters. Also, manganese is antiferromagnetic in bulk but ferromagnetic in nanoclusters. A small nanocluster is a nanomagnet, which can be made nonmagnetic simply by changing its structure. So they can form the basis of a nanomagnetic switch. | 0 | Colloidal Chemistry |
On August 16, 2016, the US food and drug administration ([https://www.fda.gov/ FDA]) published a draft guidance [https://www.fda.gov/files/drugs/published/Regulatory-Classification-of-Pharmaceutical-Co-Crystals.pdf Regulatory Classification of Pharmaceutical Co-Crystals]. In this guide, the FDA suggests treating co-crystals as polymorphs, as long as proof is presented to rule out the existence of ionic bonds. | 1 | Solid-state chemistry |
A 12" x 12" x 0.6" thick 316L steel CMF panel with a weight of 3.545 kg was tested in a torch-fire test. In this test, the panel was exposed to over 1204 °C temperatures for 30 minutes. Upon reaching the 30 minutes' time of exposure, the maximum temperature on the unexposed surface of the steel was 400 °C (752 °F) at the center of the plate directly above the jet burner. This temperature was well below the required temperature rise limit of 427 °C; therefore, this sample met the torch fire test requirements. For reference, a solid piece of equal volume steel used for calibration failed this test in about 4 minutes.
It is worth mentioning that the same CMF panel prior to the above-mentioned jet fire testing was subjected to a pool-fire test. In this test, the panel was exposed to 827 °C temperatures for 100 minutes. The panel withstood the extreme temperature for 100 minutes with ease, reaching a maximum backface temperature of 379 °C, far below the 427 °C failure temperature. For reference, the test was calibrated using an equal-sized piece of solid steel that failed the test in approximately 13 minutes. These studies indicate the extraordinary performance of CMF against fire and extreme heat.
Composite metal foam has a very low rate of heat transfer and has proven to isolate an extreme temperature of 1,100 °C (2,000 °F) within only a few inches, leaving the material at room temperature just about two inches away from a region of white-hot material. In addition, the steel CMF managed to retain most of its steel-like strength at this temperature while remaining as lightweight as aluminium, a material that would melt instantly at this extreme temperature. | 0 | Colloidal Chemistry |
The natural ability of nanoparticles to self-assemble can be replicated in systems that do not intrinsically self-assemble. Directed self-assembly (DSA) attempts to mimic the chemical properties of self-assembling systems, while simultaneously controlling the thermodynamic system to maximize self-assembly. | 0 | Colloidal Chemistry |
He developed accurate characterization method of nanoscale pores with gas adsorption and established new nanospaces-molecular science; he found unusual in-pore high pressure effect of nanoscale pores in which molecules and/or atoms prefer to form high pressure phase even without compression. One representative example of the in-pore high pressure effect is spontaneous formation of atomically 1D sulfur-chain of metallic property inside carbon nanotube under vacuum. Also he found partial dehydration of ions by confinement of ions in nanoscale pores, being essential to understand the supercapacitors.
He gave a reasonable clue, cluster- associated hydrophobic-to-hydrophilic transformation, to understand water adsorption of nanoporous carbons of hydrophobicity hydration. He contributed to understand adsorption of supercritical gases such as NO, CH , and H on nanoporous materials. He introduced the concept of quasi-vaporization of supercritical gases through an intensive molecule-pore interaction, giving an efficient guideline for improving adsorption of supercritical gases. He has developed an efficient separation route of isotopic gases such as O and O. He evidenced partial breaking of Coulombic law in electrically conductive carbon pores to induce association of cations or anions. He developed a sol-gel dispersant of single wall carbon nanotube, producing highly transparent conductive films and stretchable electrodes. | 1 | Solid-state chemistry |
When simple salts dissolve, they dissociate into individual ions, which are solvated and dispersed throughout the resulting solution. Salts do not exist in solution. In contrast, molecular compounds, which includes most organic compounds, remain intact in solution.
The solubility of salts is highest in polar solvents (such as water) or ionic liquids, but tends to be low in nonpolar solvents (such as petrol/gasoline). This contrast is principally because the resulting ion–dipole interactions are significantly stronger than ion-induced dipole interactions, so the heat of solution is higher. When the oppositely charged ions in the solid ionic lattice are surrounded by the opposite pole of a polar molecule, the solid ions are pulled out of the lattice and into the liquid. If the solvation energy exceeds the lattice energy, the negative net enthalpy change of solution provides a thermodynamic drive to remove ions from their positions in the crystal and dissolve in the liquid. In addition, the entropy change of solution is usually positive for most solid solutes like ionic compounds, which means that their solubility increases when the temperature increases. There are some unusual ionic compounds such as cerium(III) sulfate, where this entropy change is negative, due to extra order induced in the water upon solution, and the solubility decreases with temperature.
The lattice energy, the cohesive forces between these ions within a solid, determines the solubility. The solubility is dependent on how well each ion interacts with the solvent, so certain patterns become apparent. For example, salts of sodium, potassium and ammonium are usually soluble in water. Notable exceptions include ammonium hexachloroplatinate and potassium cobaltinitrite. Most nitrates and many sulfates are water-soluble. Exceptions include barium sulfate, calcium sulfate (sparingly soluble), and lead(II) sulfate, where the 2+/2− pairing leads to high lattice energies. For similar reasons, most metal carbonates are not soluble in water. Some soluble carbonate salts are: sodium carbonate, potassium carbonate and ammonium carbonate. | 1 | Solid-state chemistry |
Quick clay has a remolded strength which is much less than its strength upon initial loading. This is caused by its highly unstable clay particle structure.
Quick clay is originally deposited in a marine environment. Clay mineral particles are always negatively charged because of the presence of permanent negative charges and pH dependent charges at their surface. Because of the need to respect electro-neutrality and a net zero electrical charge balance, these negative electrical charges are always compensated by the positive charges born by cations (such as Na) adsorbed onto the surface of the clay, or present in the clay pore water. Exchangeable cations are present in the clay minerals interlayers and on the external basal planes of clay platelets. Cations also compensate the negative charges on the clay particle edges caused by the protolysis of silanol and aluminol groups (pH dependent charges). So, clay platelets are always surrounded by an electrical double layer (EDL), or diffuse double layer (DDL). The thickness of EDL depends on the salinity of water. Under salty conditions (at high ionic strength) EDL is compressed (or said to be collapsed). It facilitates the aggregation of clay platelets which flocculate and stick together in a more stable aggregates structure. After the marine clay deposit is uplifted and is no longer exposed to salt water conditions, rainwater can slowly infiltrate the poorly compacted clay layer and the excess of NaCl present in seawater can also diffuse out of the clay. As a result, the EDL is less compressed and can expand. It results in a stronger electrostatic repulsion between negatively charged clay platelets which can more easily become dispersed and form stable suspensions in water (peptization phenomenon). The effect leads to a destabilization of the clay aggregates structure.
In case of insufficient mechanical compaction of the clay layer, and with a shear stress, the weaker EDL compression by the salts in the quick clay results in clay particle repulsion and leads to their realignment in a structure that is weaker and unstable. Quick clay regains strength rapidly when salt is again added (compression of the EDL), which allows clay particles to restore their cohesion with one another. | 0 | Colloidal Chemistry |
Copper(II) chloride has some highly specialized applications in the synthesis of organic compounds. It affects the chlorination of aromatic hydrocarbons—this is often performed in the presence of aluminium oxide. It is able to chlorinate the alpha position of carbonyl compounds:
This reaction is performed in a polar solvent such as dimethylformamide, often in the presence of lithium chloride, which accelerates the reaction.
, in the presence of oxygen, can also oxidize phenols. The major product can be directed to give either a quinone or a coupled product from oxidative dimerization. The latter process provides a high-yield route to 1,1-binaphthol:
Such compounds are intermediates in the synthesis of BINAP and its derivatives.
Copper(II) chloride dihydrate promotes the hydrolysis of acetonides, i.e., for deprotection to regenerate diols or aminoalcohols, as in this example (where TBDPS = tert-butyldiphenylsilyl):
also catalyses the free radical addition of sulfonyl chlorides to alkenes; the alpha-chlorosulfone may then undergo elimination with a base to give a vinyl sulfone product. | 1 | Solid-state chemistry |
A possible solution for PFAS-contaminated wastewater treatment has been developed by the Michigan State University-Fraunhofer team. Boron-doped diamond electrodes are used for the electrochemical oxidation system where it is capable of breaking PFAS molecular bonds which essentially eliminates the contaminates, leaving fresh water. Cory Rusinek, an electrochemist at MSU-Fraunhofer stated:
Acidimicrobium sp. strain A6 has been shown to be a PFAS and PFOS remediator. PFAS with unsaturated bonds are easier to break down: the commercial dechlorination culture KB1 (contains Dehalococcoides) is capable of breaking down such substances, but not saturated PFAS. When alternative, easier-to-digest substrates are present, microbes may prefer them over PFAS. | 0 | Colloidal Chemistry |
A xanthate is a salt or ester of a xanthic acid. The formula of the salt of xanthic acid is (where R is organyl group and M is usually Na or K). Xanthate also refers to the anion . The formula of a xanthic acid is , such as ethyl xanthic acid, while the formula of an ester of a xanthic acid is , where R and R are organyl groups. The salts of xanthates are also called O-organyl dithioates. The esters of xanthic acid are also called O,S-diorganyl esters of dithiocarbonic acid. The name xanthate is derived from Ancient Greek (xanthos) meaning yellowish or golden', and indeed most xanthate salts are yellow. They were discovered and named in 1823 by Danish chemist William Christopher Zeise. These organosulfur compounds are important in two areas: the production of cellophane and related polymers from cellulose and (in mining) for extraction of certain sulphide bearing ores. They are also versatile intermediates in organic synthesis. | 1 | Solid-state chemistry |
Group 14 analogues of alkenes and alkynes have previously been prepared. Moving down the group, the compounds experience increasing geometric distortion, becoming increasingly trans-bent from the original linear geometry and displaying increasingly limited shortening of the multiple bond. These patterns are also observed in group 13 multiply-bonded compounds. These geometry trends are rationalized below. | 1 | Solid-state chemistry |
Mercury(II) iodide is produced by adding an aqueous solution of potassium iodide to an aqueous solution of mercury(II) chloride with stirring; the precipitate is filtered off, washed and dried at 70 °C.
: HgCl + 2 KI → HgI + 2 KCl | 1 | Solid-state chemistry |
Materials in certain cosmetics such as sun cream, moisturizer, and deodorant may have potential benefits from the use of nanochemistry. Manufacturers are working to increase the effectiveness of various cosmetics by facilitating oil nanoemulsion. These particles have extended the boundaries in managing wrinkling, dehydrated, and inelastic skin associated with aging. In sunscreen, titanium dioxide and zinc oxide nanoparticles prove to be effective UV filters but can also penetrate through skin. These chemicals protect the skin against harmful UV light by absorbing or reflecting the light and prevent the skin from retaining full damage by photoexcitation of electrons in the nanoparticle. | 0 | Colloidal Chemistry |
* To increase pulmonary compliance.
* To prevent atelectasis (collapse of the alveoli or atriums) at the end of expiration.
* To facilitate recruitment of collapsed airways.
Alveoli can be compared to gas in water, as the alveoli are wet and surround a central air space. The surface tension acts at the air-water interface and tends to make the bubble smaller (by decreasing the surface area of the interface). The gas pressure (P) needed to keep an equilibrium between the collapsing force of surface tension (γ) and the expanding force of gas in an alveolus of radius r is expressed by the Young–Laplace equation: | 0 | Colloidal Chemistry |
Peptides based hydrogels possess exceptional biocompatibility and biodegradability qualities, giving rise to their wide use of applications, particularly in biomedicine; as such, their physical properties can be fine-tuned in order to maximise their use. Methods to do this are: modulation of the amino acid sequence, pH, chirality, and increasing the number of aromatic residues. The order of amino acids within the sequence is crucial for gelation, as has been shown many times. In one example, a short peptide sequence Fmoc-Phe-Gly readily formed a hydrogel, whereas Fmoc-Gly-Phe failed to do so as a result of the two adjacent aromatic moieties being moved, hindering the aromatic interactions. Altering the pH can also have similar effects, an example involved the use of the naphthalene (Nap) modified dipeptides Nap-Gly-Ala, and Nap- Ala-Gly, where a drop in pH induced gelation of the former, but led to crystallisation of the latter. A controlled pH decrease method using glucono-δ-lactone (GdL), where the GdL is hydrolysed to gluconic acid in water is a recent strategy that has been developed as a way to form homogeneous and reproducible hydrogels. The hydrolysis is slow, which allows for a uniform pH change, and thus resulting in reproducible homogenous gels. In addition to this, the desired pH can be achieved by altering the amount of GdL added. The use of GdL has been used various times for the hydrogelation of Fmoc and Nap-dipeptides. In another direction, Morris et al reported the use of GdL as a molecular trigger to predict and control the order of gelation. Chirality also plays an essential role in gel formation, and even changing the chirality of a single amino acid from its natural L-amino acid to its unnatural D-amino acid can significantly impact the gelation properties, with the natural forms not forming gels. Furthermore, aromatic interactions play a key role in hydrogel formation as a result of π- π stacking driving gelation, shown by many studies. | 0 | Colloidal Chemistry |
In general, metal nanoclusters in an aqueous medium are synthesized in two steps: reduction of metal ions to zero-valent state and stabilization of nanoclusters. Without stabilization, metal nanoclusters would strongly interact with each other and aggregate irreversibly to form larger particles. | 0 | Colloidal Chemistry |
Nazar works in materials chemistry at the University of Waterloo, where she designs energy storage devices and electrochemical systems. Her research group create new materials and nanostructures for lithium–sulfur batteries, including interwoven composites. She develops structural probes to understand how the morphology of materials that are capable of charge/ ionic redox processes impact their functions. These techniques include nuclear magnetic resonance (NMR), electrochemistry, AC Impedance Spectroscopy and X-ray diffraction measurements. Nazar was a founding member of the Waterloo Institute for Nanotechnology. Nazar is recognised as being a "leading authority in advanced materials". She was awarded a Canada Research Chair in 2004, which was renewed in 2008 and 2012. In 2009 Nazar joined the California Institute of Technology as a More Distinguished Scholar. In 2013 she was awarded a $1.8 million fellowship from the National Research Council to investigate energy storage materials for automotive applications.
Nazar is particularly interested in storage materials that go beyond lithium-ion batteries, sodium-ion batteries, zinc ion batteries and magnesium-ion batteries. Lithium-ion batteries are the battery of choice in hybrid electric vehicles, but concerns have arisen about the global supply of lithium. Her early work developed porous carbon architectures as frameworks for cathodes, enhancing their conductivity and discharge capacity. She demonstrated that interwoven carbon composites could be used to improve the energy density of lithium–sulphur batteries. She showed it was possible to create mesoporous carbon frameworks that constrain the grown of sulphur nanofillers, which improved energy storage and reversibility.
Nazar calculated the low-cost lithium–sulphur batteries could take electric cars twice as far as current lithium-ion technologies. Sulphur is an abundant material that can be used to replace cobalt oxide in lithium-ion batteries. Unfortunately, sulphur can dissolve into the electrolyte solution, and be reduced by electrons to form polysulphides. They are also susceptible to high internal resistance and capacity fading on cycling. These challenges can be overcome by creating nanostructures in the electrodes. Interwoven composites can also be made from manganese dioxide, which stabilise polysuplphides in lithium–sulphur batteries. Manganese dioxide reduces sulphides via a surface-bound polythiosulphanates, and can withstand 2,000 discharge cycles without the loss of capacitance. She has also developed lithium oxygen batteries, which are lightweight with high energy density. In lithium oxygen batteries, superoxide and peroxide can act to degrade the cells; limiting their lifetime. If the electrolyte is replaced with a molten salt and the porous cathode with a bifunctional metal oxide, the peroxide does not form. Nazar has worked on supercapacitors and polyanion materials.
She was made a Professor at the University of Waterloo in 2016 and holds a Tier 1 Canada Research Chair in Solid State Energy Materials. Since 2014 Nazar has served on the board of directors of the International Meeting on Li-Batteries. She serves on the editorial boards of the journals Angewandte Chemie, Energy & Environmental Science and the Journal of Materials Chemistry A. | 1 | Solid-state chemistry |
The DNA analyzers developed at Illumina, which was co-founded by Czarnik in 1998, use the patented technology of multiplex decoding of array sensors with microspheres to read genetic codes. As a result, the analyzers have reduced the cost of sequencing a human genome. | 1 | Solid-state chemistry |
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