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Since prehistory man has been aware of the importance of particle size in producing resources and wares with desired properties. Archeological evidence indicates that paints used for cave wall paintings are mixtures of finely pulverized pigmenting materials, predominantly carbon, ochre and hematite. Man came to realize that adding pulverized materials to clay not only improved its workability, but improved the drying process, reduced shrinkage and changed the characteristics of the resulting vessels. There also is evidence of using particles of certain sizes to control porosity.
For many centuries, finely divided, calcined lime powder or gypsum mixed with sand was used in plasters and binders. Then, about 2000 years ago, the Romans improved upon the formula by adding volcanic (pozzolanic) ash, which produced a superior hydraulic cement that was used in building many structures that still stand.
Today, finely divided particulate materials and objects that incorporate or are produced from these fine particles are everywhere about us. Frequently encountered powders include cement, lime, fertilizer, cosmetic powders, table salt and sugar, detergents, bath and dental powders, coffee creamer, baking soda, and many other household items. Products in which the incorporation of powders is not so obvious include paint, toothpaste, lipstick, mascara, chewing gum, magnetic recording media, many medicinal products, slick magazine covers, floor coverings, and automobile tires.
Such everyday items as fused ceramic bathroom fixtures and many small metal objects produced by powder metallurgy completely obscure their origins as powders. The gold trim of dinnerware, for example, started as a carefully controlled fine powder. Even microwave cooking utilizes particle technology. The desire to brown some foods cooked by microwave was solved by a wrapping of metalized polyethylene terephthalate (PET) film, a material containing fine grained metallic material that absorbs microwaves and produces localized elevated temperatures.
The applications of fine particle technology by no means are limited to commercial products, nor is the need to determine the properties of finely divided materials restricted to one area of technology. It begins in mining with discovering how fine an ore must be ground to release the sought-after mineral.
Detailed physical studies of archeological items indicate that these processes were known in ancient times. Fine ceramic artefacts indicate a knowledge of processing naturally occurring rocks and minerals to control purity as well as particle size distribution in the clays, glazes, and pigments. Plasters used in decorating the pyramids and mortars used by Roman masons indicate similar attention to particle size.
Today the porosity of limestone and sandstone is characterized by quarry source and related to its expected rate of deterioration in urban environments before it is used in restoration of historic monuments. The mortars and plasters used in ancient and modern times owes its characteristics almost wholly to the selection of the proper sizes of the lime and filler particles.
Geologists study the textural characteristics of clastic rocks to extract clues to the methods of transportation, sorting, and deposition of the fine materials incorporated in these rocks. This provides valuable information about the history of natural events and processes such as water flow, winds, glacier movement, and marine currents that occurred at the depositional site prior to lithification.
Petroleum geologists study the physical characteristics of strata deep within the earth in order to determine the capacity of the field and to assess the effort required to remove the petroleum. Oceanographers measure characteristics of marine sediment for clues to its origin as well as to determine its mechanical properties for mooring. Soil scientists examine characteristics of near-surface soils to assess qualities associated with agricultural production. Many of the physical characteristics of interest to these scientists are dependent upon characteristics of the fine particles from which the materials are composed.
Climatologists are concerned with airborne particles that affect weather, and historical climatologists study particle depositions in ice cores as evidence of weather patterns over thousands of years. Climatologists, paleontologists and other natural scientists have found evidence linking mass extinction to an excessive number of fine particles in the upper atmosphere that shielded solar energy from the earth's surface, initiating a chain of events that devastated flora and fauna world-wide. Civil engineers study the grain size of subsurface soils to assess load bearing capabilities.
Environmentalists must know the capacity of adsorbents such as carbon granules in order to prevent escape of harmful vapors into the atmosphere. They also must characterize soil to determine the percolation rate, diffusion, and retention characteristics of hazardous substance spills. These bulk characteristics, too, are dependent upon the characteristics of the individual particles that compose the bulk.
There is an optimum particle size, or at least a smallest and largest acceptable size, for most items involving particles.
The taste of both peanut butter and chocolate is affected by the size of their respective ingredients. Extremely fine amorphous silica is added to tomato ketchup to control its flow. Pharmaceutical tablets dissolve in our systems at rates determined in part by particle size and exposed surface area. Pigment size controls the saturation and brilliance of paints. The setting time of concrete, dental fillings, and broken-bone casts proceeds in accordance with particle size and surface area exposure.
Some materials, gums in particular, do not dissolve in water but absorb water to form viscous colloidal sols. The particle size of the powder determines the type of dispersion. Larger particles form a discontinuous mucilage and fine powders yield homogeneous dispersions. The former is an effective ingredient in laxatives while the latter finds use in adhesives.
Controlling the surface-to-volume (surface-to-mass) ratio is one reason for manipulating particle size. Another is to control interparticle pore size and pore volume for specialized applications. For example, at the turn of the nineteenth century, filters having sub-micron pore sizes were constructed from diatomaceous earth and used to retain bacterium. However, it was demonstrated that infectious particles far smaller than bacteria could pass through these filters, leading to confirmation of the existence of unfilterable infectious elements called 'viruses'.
Surface area and porosity as a function of particle size or surface area and porosity independent of particle size are other physical characteristics that play an important role in particle technology. The effectiveness of odor removers depends on the active surface area of the adsorbent in them. The tightness of the weave of a cloth raincoat, and therefore its porosity, is adjusted to retard water penetration but permit air and vapour passage for comfort. Adsorbent towels and tissues, on the other hand, are made to have pores that readily wick up liquids. The tips of felt-tip pens have a still different requirement: their pore structure must hold a viscous ink but release it when compressed.
The pore structure of prosthetic devices influences whether or not tissue will attach. There is even a connection between the Sphinx of Egypt's Giza plateau and porosity. The Sphinx may be coerced into revealing its true age thanks to the porosity of the stone from which it is made. A model of the weathering process based on the porosity of the stone has been suggested that may yield a timeline back to the date of its creation.
Many behavioural aspects of fine particle systems come about simply because of the relatively large amount of surface exposed to its surroundings. As matter is subdivided, the free energy of the system increases proportional to the amount of new surface created. The work required to achieve the new surface is equal to or greater than the increase in free energy. However, the laws of thermodynamics dictate that a system spontaneously will seek the lowest free energy state that is possible under the circumstances. The study of the behaviour of the system in seeking this state, and how it can be manipulated and utilized is the domain of fine particle technology.
A thought experiment that exemplifies these principals is as follows. Consider a container of oil and water, the oil floating above the water, the two liquid phases being separated by a surface of minimum area and minimum free energy. Adding work to the system by vigorously shaking the container results in oil droplets being dispersed in the water and the total surface of the oil-water interface being greatly increased. However, when allowed to again stand at rest, the droplets join to form larger and larger drops of oil, each having less surface than the sum of the surfaces of the individual droplets that formed it, thereby reducing surface free energy. This behaviour continues until the minimum interface is achieved, that is, one mass of oil floating above the mass of water.
The system could be manipulated by adding a surfactant that would be attracted to the surface of the oil droplets, thus lowering the free energy of these surfaces and suppressing or prohibiting their coalescence when the input of agitation energy is ceased.
The mechanism employed to achieve minimum energy in the example above is through the mutual attraction of matter. This non-specific attractive force is commonly referred to as van der Waals force. It gives rise to the phenomenon termed physical adsorption (or physisorption) and is also responsible for surface tension and condensation in liquids. At high temperatures surface energy is likely to be reduced by electron sharing and valence bonding with gas atoms creating the phenomenon known as chemical adsorption (or chemisorption). As has been exemplified, some of the attraction can be reduced by the addition of surfactants, which give rise to what is called double-layer phenomena.
Obviously, all the special attributes relating to particle size, surface properties, and pore structure could not have been achieved without precise measuring means.
Particle size probably was measured crudely first in ancient Egypt. Surviving wall paintings show ground foodstuff being sieved—possibly through a rough cloth of woven reeds—to remove the large bits for further grinding. While undoubtedly it was recognized long ago that grinding to smaller and smaller sizes exposed progressively more surface area and promoted dissolution, truly assessing the extent of the exposed area and the consequences thereof got its start only in the eighteenth century.
This is when it was discovered that charcoal heated and then cooled without exposure to air would take up several times its own volume of air upon subsequent exposure. That pores in the charcoal accounted for much of the gas uptake by its condensation in them and that all solids exhibited adsorption phenomena to different degrees was learned by the mid-nineteenth century. From that came the realization that gas adsorption measurements could yield much information about the physical surface and pore structure of solids.
Continuing experimentation early in the twentieth century with gases being first adsorbed and then removed by heating revealed that more was involved in some instances than just physical adsorption. Oxygen gas, for example, removed from carbon was found not to be pure oxygen but to contain oxides of carbon. This suggested that two processes were involved in gas uptake on solids: one of purely physical character which, as used above, was given the designation physical adsorption, and one involving a chemical reaction which is termed chemisorption. Adjacent chemisorbed atoms become susceptible to reaction with one another to form new chemical species when the proper surface structures and conditions are present. This we now know is the action of catalysts. Today, chemists and chemical engineers tailor the pore size and surface properties of catalysts to produce everything from shortening to gasoline.
Providing quantitative measures of the several parameters defining particle size, surface area, pore size and volume, surface activity, object density, and a few other more specialized subjects is the purpose of the instruments and services Micromeritics offers.
Following are details of just what is being determined when each measurement is made with Micromeritics' instruments.
If all fine particles were spheres, their size would be defined explicitly by their diameter or radius. If cubical, the length along one edge would be characteristic; if of some other regular shape, another equally appropriate dimension could be chosen. Unfortunately the great majority of particles are quite irregular and an arbitrary definition of "size" is the only resort, short of detailed examination of each particle. Moreover, every collection of particles contains particles of many different sizes, commonly referred to as the particle size distribution. Hence a practical definition of particle size must permit a great number of particles to be examined in a relatively short time.
What is termed an equivalent spherical diameter best meets the requirement for a non-specific measure. Equivalence of size means that the "diameter" assigned to an irregularly shaped particle is the same diameter as that of a sphere which behaves identically when both are exposed to that same process.
There are numerous manual and automated techniques by which to determine the mass vs. equivalent size distribution of a collection of particles. Selecting the most appropriate technique is critical in attaining reliable data. No single technique is superior in all applications.
Micromeritics' SediGraph particle size analyzer measures the distribution of equilibrium velocities of particles settling through a liquid under the influence of gravity. Stokes' law relates these velocities to particle diameters for spherical particles. The instrument determines the settling velocity of the particles and applies Stokes' law to determine diameters. It thus measures non-spherical particles in terms of the diameter of a sphere of the same material that settles at the same velocity, i.e., it determines equivalent spherical diameters.
Most powders used in manufacturing processes are at some point mixed into or compounded with a liquid. Predicting the behaviour of such a mixture is more likely to be successful if particle diameters are known. Since the sizing of particles by the sedimentation technique also involves dispersing powders in a liquid, the analysis essentially is performed in situ. This benefit also extends to studies of marine silts and sediments, the deposition of the solids being dependent upon their sedimentation velocity in a liquid, a fundamental measurement when sizing by the sedimentation technique.
The sedimentation velocity of suspended particles can be obtained by measuring the quantity of sediment produced as a function of time or by measuring the concentration of particles remaining in suspension with time. The latter approach is preferable mathematically and is employed by Micromeritics. The instrument design in which this approach is implemented utilizes a beam of low-energy X-rays to measure mass concentration in terms of the transmittance of the suspension relative to the suspending liquid. The transmittance to X-ray wavelengths is a function only of the mass concentration of the suspended particles. The X-ray beam is extremely narrow in the vertical dimension, and because it does not disturb the suspension it constitutes an ideal measuring probe.
Small particles settle quite slowly under gravity. To avoid the long settling times that would be required to measure both the larger, faster-settling particles and the smaller, slower-settling ones, the cell containing the particles is moved downward with time relative to the X-ray beam. The entire cell is thus scanned in a matter of minutes and particle size resolution is achieved as rapidly as could have been obtained by centrifuging the cell but without the mechanical complications of a rotating element.
Most of the analysis processes are automated to reduce or eliminate operator error, thus assuring repeatability and reproducibility of results. As examples, the movement of the cell is computer controlled as is the introduction of sample and the flushing away of it when the test is done. An accessory unit permits multiple samples to be selected and then analyzed automatically in any order desired.
Powdered materials having diameters from 0.1 to 300 mm (micrometers) can be measured with a precision of 1 mass percent over the entire size range provided three criteria are met: the particles must be more dense than the liquid in which they are suspended; the particles must disperse, or break free of one another, in the liquid; and the particles must absorb more X-rays than the liquid so that adequate contrast with the liquid is created. The last criterion generally means that the materials must contain elements having atomic numbers greater than 11 (sodium).
Powders, particularly fine ones, often are difficult to disperse, i.e., separate into individual entities with each particle free and not attached to one or more other particles.
Unless the dispersed state is achieved, particle size measurement by sedimentation, or any other method for that matter, can be greatly misleading. Micromeritics has developed a series of liquids which greatly facilitates the dispersion of difficult-to-disperse powders.
The most common application of this technique is low angle light scattering (LALS) in which an assemblage of particles is illuminated by a source of monochromatic, coherent light. This is the technique employed by Micromeritics' DigiSizer.
In this instrument design, a lens is positioned in such a way that light scattered at a specific angle from any particle in the illuminated zone will intersect the focal plane at a specific distance relative to the focal point. The intensity of scattered light is measured at a number of predetermined positions corresponding to a set of scattering angles. Using these intensity vs. forward angle measurements, Mie or Fraunhofer theory (a special case of Mie theory) can be applied to extract particle size information. Mie theory predicts the intensity of scattered light over a 180-degree range of scattering angles. Using intensities measured only at low angles (<90 degrees), the sizes of particles over a range of about 0.1 to 1000 mm can be determined. Mie theory, in the strictest sense, applies only to spherical, isotropic particles with specific and known optical properties. However, Mie theory most often is applied to particle systems that do not exactly conform to the theoretical model. As with the sedimentation technique, particle size is reported as equivalent sizes. In the case of light scattering, the reported quantity vs. size distribution is that of spherical particles that most closely reproduce the same scattering pattern as that of the particle assemblage being analyzed.
All information about particle size and quantity resides in the intensity versus angle characteristics of the scattering pattern; therefore, precise measurement of the light scattering characteristics are fundamental to obtaining good particle size data. A unique design feature of Micromeritics' DigiSizer is the use of a high-resolution detector array (a charge coupled device or CCD) to measure scattered light. The spatial density of detector elements is so great that several million measurements are collected between 0 and 36 degrees of scattering angle and an angular resolution of a few thousandths of a degree is achieved. Due to the symmetry of the scattering pattern in the area of measurement, many of the intensity measurements are for the same scattering angle and these redundant measurements provide real-time signal averaging.
Another benefit gained by use of a CCD is a means of accommodating a wide range of light intensity. This is because the CCD is inherently an integrating device rather than a current-generating device such as a photodiode. The charge accumulated by a CCD element is proportional to the product of the intensity of incident light and the exposure time. Very low light intensities are measured by allowing long exposure times, and very high light intensities are measured using microsecond exposures. This capability is important in measuring a scattering pattern in which light intensities can vary over a range of ten orders of magnitude.
The high-resolution angular detection allowed by the area array permits the position of the optical axis (the position of the central, unscattered light beam) to be determined within a fraction of one pixel element, that is, a few thousandths of a degree.
This point represents the origin of the polar axis about which the scattering pattern is centered. Relative to this point, a scattering angle can be assigned by software to all other detector element. If any mechanical or optical deviations cause the optical axis to move from the zero point, it is promptly determined by software and the detector array is dynamically remapped, thus, mechanical alignment is unnecessary.
Once the scattering pattern has been characterized by a set of angle vs. intensity data, the final step is to determine the sizes and quantities of particles that will most closely reproduce the measured scattering pattern. This is accomplished by an iterative process of fitting theoretical models to the data using a non-negative least square method.
The same caveat about liquid-solid dispersions that applies to the sedimentation technique and the SediGraph applies also to particle sizing by static light scattering.
However, in some applications, the objective may be to study dispersion or flocculation characteristics. In this case, a sample recirculating system such as the DigiSizer's Liquid Sample Handling System provides a means by which the size distribution characteristics of the same sample can be measured repeatedly as the process under study evolves.
The electrical sensing zone (ESZ) technique, also known as the Coulter principle, analyzes the sample particle by particle rather than examining an assemblage of particles as done in the two techniques discussed previously. Micromeritics' Elzone analyser utilizes this technique to count and size particles.
To analyze a sample by the ESZ technique, a homogeneously dispersed suspension of sample material is prepared in an electrolytic solution. A tube with a small aperture of short path length is submerged in the suspension, an electrode being positioned on both sides of the aperture. A pump establishes a flow of electrolyte through the aperture, providing a conductive path between the two electrodes and a small electrical current is established between them. Both electrolyte and particles pass through the aperture. The particles, being non-conductive, impede the electrical current flow as they enter the orifice. This creates an electrical signal proportional to the volume of the particle in the aperture. Each individual particle is counted and classified according to volume, thus producing a volume frequency distribution. If the particles are considered to be spherical, then particle diameter can be determined from volume.
The concentration of particles in the electrolyte is very dilute since two or more particles entering the orifice in close succession will cause an erroneous signal. However, statistical probability dictates that a coincidence of particles will occur in the orifice now and then, so a coincidence correction routine is built into the software to correct for such events.
The ESZ technique is applicable to a wide range of sample materials including plant and animal cells. It is particularly useful when the number distribution of particles by size needs to be determined. ESZ also is a very high-resolution method of particle sizing.
There is an inverse relationship between particle size and surface area. A cube one centimeter on an edge has a surface area of 6 cm2. If the cube were fragmented into smaller cubes having edges of 0.1 cm there would be 1000 of the smaller cubes and the total surface area would have become 60 cm2 . This ideal relationship is unlikely ever to be encountered because irregular particles break into smaller particles with a range of sizes and shapes. Actual particles of whatever size, if examined on a molecular scale, display planar regions, but they also are likely to include lattice distortions, dislocations, and cracks. This means that the actual exposed surface of particles is greater – sometimes very much greater - than would be calculated assuming any one geometric shape.
Micromeritics' provides several types of surface area instruments that permit determination of surface areas at the molecular level by measurement of a low temperature isotherm. At the upper end of the range are multipurpose, sophisticated units capable of providing timely results for both quality control and research and development needs. Midrange instruments include those for high throughput, round-the-clock, reliable service for quality and production control purposes. At the lower end are inexpensive, semi-automatic and manual instruments for occasional usage. Properties other than surface area can be determined from the data provided by these instruments – chemical activity and pore structure are examples; only the surface area function is described in this section.
All such instruments first free the sample of moisture and atmospheric vapours by application of heat and either evacuation or purging with a non-adsorbing gas, usually helium or nitrogen (nitrogen may adsorb at room temperatures on some materials). Then the sample temperature is reduced to that of liquid nitrogen, liquid argon, or another coolant appropriate for the gas or vapour to be adsorbed. The adsorbing gas is admitted in incremental doses in one instrument design (static volumetric technique), continuously as the sample itself permits in another design (adaptive rate technique), and as a component in a flowing mixture with nonadsorbing helium in still another design (dynamic, or continuous flow technique). The accumulated gas quantity adsorbed vs. gas pressure data at one temperature are then graphed to generate what is called an adsorption isotherm.
The data are then treated in accordance with gas adsorption theories to arrive at a specific surface area value for the sample.
Classical adsorption theory that has been in use since the 1930's and is still in use assumes that gas molecules admitted under increasing pressure to a clean, cold surface form a layer one molecule deep on the surface before beginning a second layer. The data treatment technique finds the quantity of gas forming this first layer, and then the area covered is calculated from the number of molecules of the gas and gas molecule dimensions. Actually, adsorbed gas molecules do not attach to a solid surface and thereafter remain attached while other molecules build upon them. In the first place, there are regions on all surfaces that are more attractive to gas molecules and regions that are less so. What we call adsorption is really the manifestation of a continual exchange between gas molecules temporarily residing on a solid surface and those nearby in the gas phase. The number of molecules attached to a solid at any instant increases as gas pressure increases until a point is reached where statistically it is reasonable to consider a monolayer to have formed. Only in the sense of an average condition does an adsorbed monolayer ever really exist, however.
Many modifications to the classical model have been offered over the years, some based on empirical or semi-empirical foundations and others derived from either thermodynamics or kinetic theory. All of these data reduction methods have the common attribute of applying only to a certain segment of the isotherm rather than over the full range. A more modern approach is to begin with basic principles of statistical thermodynamics, combine these building blocks with newly available computational techniques, and seek a single or unified theoretical model applicable over the total range of the isotherm. This approach utilizes density functional theory, and an efficient implementation of this theory by Micromeritics enables rapid calculations of this once computationally intractable data reduction task.
Density functional theory is a means by which the exact population density of a system of molecules at a specific temperature and pressure can be expressed mathematically. When the expression is solved for the state of minimum energy, the population density profile at equilibrium is described. Since the energy of the system must take into regard surface energies of a solid substrate exposed to the system of molecules, the population density profile reveals how various layers of molecules have formed on and near the solid surface. This method allows the acquisition of a family of profiles that describes gas adsorption over a range of pressures from near zero to the saturation pressure.
The less sophisticated Micromeritics instruments start with classical theory, but others, through their software computational capability, can report results obtained by classical theories as well as by recent, popular adsorption theories with applicability limited to specific conditions and ranges. Density functional theory can be utilized with all adsorption isotherms. However, it is best used with the more sophisticated instruments that are capable of collecting high resolution low-pressure data, thus, providing the highest quality results.
Accessory equipment is provided for minimizing operator involvement and speeding sample preparation. This includes units for degassing samples by the flowing gas method or by applying heat and vacuum. A liquid cryogen storage and transfer system also is provided for making more convenient the supplying of sample coolant for all instruments.
Solid particles from crushing or grinding operations and weathering or leaching processes often will be found to have cracks, cavities, and holes (collectively called pores) within their structure. Solid particles produced by condensation or crystallization processes may contain, or acquire after a period of time, cracks along grain boundaries and at positions where impurities are occluded. Fine particles also tend to stick together, or adhere to form aggregates or larger secondary particles, giving rise to another level of pore sizes.
Adhesion is accelerated at elevated temperatures and with the mechanical application of pressure. Industrial processes that make use of this property are called firing in the case of pottery manufacture and sintering in powder metallurgy. Many of the pores in industrial products thus are comparable in dimensions to the primary particles themselves. In these cases the walls of the pores are the exposed surfaces of the particles, and, not surprisingly, these pores are likely to exhibit interconnectivity and great tortuosity. A few natural materials such as kaolin clay and mica occur as more or less orderly stacks of thin plates; graphite also can be produced with a similar structure. The pore dimensions are very small in one direction and relatively large at right angles to that direction.
Pore size is expressed either in terms of the diameter (or radius) of the opening, assuming it cylindrical, or simply as the width in a more general sense. Pores of widths less than 2 nanometers (nm), or 20 Angstrom units (Å), are referred to as micropores.
Pores having widths from 2 nm to 50 nm (500 Å) are called mesopores, and pores of larger widths are referred to as macropores. The volume of all cracks, fissures, holes, channels, etc., within the body of particles or of larger objects is the total pore volume.
The first technique for pore volume assessment condenses a gas in the pores and derives pore volumes from the quantities of gas (converted to condensed liquid volume) required. In the presentation above on surface area evaluation, it was described that an inert gas admitted to clean, cold surfaces first adsorbs to a monomolecular layer according to the classical viewpoint. Admitting more gas causes the layer to thicken to a depth of several molecules and, ultimately, to a layer of infinite thickness, i.e., condensation to bulk liquid when the saturation vapour pressure is reached. If, however, the solid is porous so that it has internal surface area, condensation of the gas will begin in the smallest pore spaces and progressively fill larger and larger pores prior to bulk condensation.
Equipment for measuring pore sizes and volumes is identical to that for determining surface area in most instances. What is required of the instruments is that gas admission to the cooled sample be continued beyond the first adsorbed gas layer to the point at which bulk condensation begins. Computation of results now also must account for the added complexity that gas continues to be adsorbed on exterior surfaces while condensation is occurring in the central core of pores which already had adsorbed gases on their walls before condensation started.
This basically means that the computation must proceed in reverse, as it were, after all pores have been filled. This is so because the assumption that all pores are filled can be made only for the last increment of added gas before bulk condensation occurs. These calculations incorporate the Kelvin capillary condensation equation which holds for pores down to about 2 nm (20 Å) diameter, i.e., down to the micropore region.
There are numerous modifications to classical theory and additional theories which encompass microporous material analysis. Precise measurements down to quite low pressures are required. The Micromeritics volumetric physical adsorption instruments are equipped to carry out pore diameter and volume analyses and to report results by most of these techniques. Those units with high vacuum manifolds are most applicable for thorough analysis of micropore structure and for reporting density functional theory calculations.
The second way Micromeritics products determine pore size information is by mercury intrusion - forcing liquid mercury into the pores and keeping inventory of the quantity penetrating them. Mercury has an exceptionally high interfacial tension and wets only a few materials, the resistance to wetting being quantified by a parameter known as the contact angle. When the contact angle is greater than 90° - mercury against most solids usually registers between 130° and 150° - increasing external pressures must be applied to cause mercury to penetrate progressively decreasing size pores. Quite high pressures are necessary to fill very small pores. Micromeritics manufactures two instruments, one capable of pressures to 207 MPa (30,000 psia), causing pore diameters to be filled down to 6 nm (60 Å) and the other with the capability of attaining pressures to 414 MPa (60,000 psia), filling pore diameters down to 3 nm (30 Å). Also offered is a device for measuring contact angles.
Sample material first is evacuated and then inundated with mercury in a mostly glass device termed a penetrometer. Pressure is applied hydraulically to both the mercury in the penetrometer and also about the sample. Subsequent penetration into pores is tracked by a change in electrical capacitance, which registers the volume of mercury penetrating pores; pressure transducers measure the corresponding pressure. Pore diameters and respective volumes are calculated from this information and from the value of contact angle. Each porosimeter instrument presents results as total pore volume, pore area, median and average pore diameters, percent porosity, incremental and cumulative pore volumes as a function of pore diameter, and more in tabular form. Various forms of graphical data also are presented.
Density is a prosaic property of all matter. It is simply the mass of a quantity of matter divided by the volume of that same quantity. Accurately determined, density reveals much about the composition of an alloy, provides information with which to keep a process under control, reveals the richness of a mineral body, and much more. There are three densities associated with powders. The absolute density (also termed the true or skeletal density) excludes the volumes of pores and of the interparticle spaces; the envelope density (sometimes called the apparent density) includes the pore volume but excludes interparticle spaces; and the bulk density includes both pore volume and interparticle spaces. For a powder, the latter changes with vibration and applied forces and is not an intrinsic property of the material.
The absolute and envelope densities of a nonporous object are identical. If the object is a relatively large cube, sphere, or other regular geometric shape, its volume is not difficult to determine nor is its absolute (and envelope) density difficult to calculate.
Difficulty in measurement becomes apparent when the material in question is of irregular shapes and especially when it is also in small bits or granules. The difficulty increases if, in addition, the material also has pores, cracks, crevices, or deep concave regions. The absolute and envelope densities differ in this case, and require separate techniques to assess. Absolute density by definition excludes all pore volumes that have access to the outside. Envelope density includes pore spaces up to the plane of the surface.
Micromeritics provides multiple instruments, manual and automatic, specifically for determining absolute density. They accept a wide range of sample sizes and operate at a range of gas pressures. All use helium gas as the standard working medium but other gases can be employed. In both, a sample of the material in question first is placed in a sealed chamber of known volume and then exposed to series of elevated and then released gas pressures to flush away atmospheric gases and vapors. Next, instead of venting the gas at elevated pressure to atmosphere, it is released into another chamber of known volume. The pressures in both chambers are determined both before and after the expansion of the gas.
This permits calculating the volume of the sample, and division of this volume into the sample weight gives the density. The result is an absolute density value because the helium fills all open spaces including that of the pores. By cutting materials that have closed pores into smaller pieces and thus exposing more of the pores, an absolute density pycnometer also can be employed to evaluate the proportion of open and closed pores.
Micromeritics also produces an instrument for determining envelope density. It operates on the principle of immersing the object, or objects, to be evaluated in a fluid medium of known volume and measuring the displaced volume. The medium, instead of being a liquid as Archimedes used, consists of free-flowing, fine spherical particles. To ensure that beads conform to the external contour of the object being measured, the object is tumbled freely in a cylinder containing both it and the beads. Gradually the space is reduced by an intruding plunger until a prescribed force is achieved. Where the plunger stops when the beads are compacted about the object is a measure of the volume of the object and the pores not intruded by the beads. Dividing this volume into the object weight yields the envelope density of the object.
The envelope density of an object in and of itself is sometimes of great utility, for instance in controlling a sintering operation. Other useful information can be calculated from the envelope and absolute density values for the same object, viz., the porosity and specific pore volume of the object. These latter parameters indicate many things from the suitability of a catalyst substrate or the yield potential of an oil-bearing formation.
Bulk density is the parameter defining how granular, fibrous and powdery materials pack or consolidate under a variety of conditions. Knowing its value is useful in packaging, handling, and shipping all manner of products from breakfast cereal to cement. The Micromeritics instrument for measuring envelope density determines bulk densities as well. The weighed, granular test sample alone is tumbled in the cylinder and the volume it occupies is measured at any pre-selected force applied by the advancing plunger. Dividing sample weight by the volume now yields bulk density. Thus the compacting behavior of a material - measured in terms of its bulk density – is established.
Physical adsorption was described previously under 'Surface Area'. It is a relatively weak attraction between the gas and the surface molecules. Chemisorption, in contrast, involves stronger solid-gas attractions.
Chemisorption is the basis from which has been developed an array of man-made materials called heterogeneous catalysts. Without catalysts the modern world would be in short supply of fertilizers, pharmaceuticals, synthetic fibers, solvents, surfactants, gasoline, and other fuels, for deep within the tiny galleries, pores and cavities of catalysts occur the chemical reactions that support our industrial society. As a specific example, the metal rhodium exposed on the surface of a ceramic honeycomb structure is the heart of the exhaust system of automobiles.
How it transforms the deadly exhaust gases of nitric oxide (NO) and carbon monoxide (CO) into harmless nitrogen (N2) and carbon dioxide (CO2) is typical of the action of a catalyst. At the high temperature of an automobile exhaust, carbon monoxide binds to the rhodium surface. When nitric oxide does the same, it dissociates into oxygen and nitrogen, and the bound oxygen reacts with the carbon monoxide to form carbon dioxide. Then when other molecules of nitric oxide and carbon monoxide land close to the remaining bound nitrogen a second carbon dioxide and a nitrogen molecule are formed.
Practical catalysts are characterized by having a high specific surface area, i.e., area per unit mass. They may consist of finely divided metal dispersed on the surface of a nonreactive, high surface area, refractory oxide such as alumina or silica. Other metal catalysts have an open, skeleton-like structure as a result of leaching away one metal of a bimetallic alloy. The newest and most exciting catalysts are termed zeolites. They consist primarily of aluminum, silicon, and oxygen but host an assortment of other elements.
They are highly porous crystals veined with submicroscopic channels. The assorted other elements can be moved about or replaced and the channels can be altered in size to make zeolites very useful indeed.
The surface area and pore structure of catalysts obviously are critical to their behaviour. Both parameters can be measured by the instruments described previously.
These tests are conducted basically as described before and their description will not be repeated. However, because catalyst surfaces are highly reactive and can be altered by exposure to the atmosphere as when transferred from one instrument to another, Micromeritics chemisorption instruments incorporate provisions for making these measurements in situ. Critical parameters for chemisorption measurement are: the area of the active element; metal dispersion, i.e., what proportion of the active element is actually exposed; surface acidity; and the strength of acid sites.
The simplest chemisorption instruments utilize the titration (dynamic, or continuous flow) technique in which small, reproducible volumes of a reactive gas such as hydrogen, oxygen, carbon monoxide, sulfur dioxide, or ammonia are injected into a flowing carrier gas such as helium that passes over the sample catalyst. Gas composition downstream is detected by matched thermal conductivity detectors. Repeated injections of identical reactive gas quantities are made from which all, most, some, and then none of each pulse is chemisorbed. The cumulative chemisorbed quantity is derived by summing the proportions of all pulses consumed. Metal surface area, dispersion, acidity, and other important parameters are derived from the chemisorbed quantity, taking into account stoichiometric factors and the nature of both the gas and metal involved. Single-injection calibration or testing can be accomplished using either a syringe or a built-in injection loop. The instrument's two-port design permits high throughput. While sample preparation is being conducted on one port, an analysis can be performed on the other.
By adding to this instrument an accessory package which contains among other things a programmable furnace, temperature-programmed desorption (TPD), temperature programmed reduction (TPR), and temperature-programmed oxidation (TPO) tests can be accomplished. Temperature-programmed desorption evaluates the gas being desorbed from a catalyst as its temperature is increased. First, the catalyst is outgassed, reduced, or otherwise prepared. Then reactive gas is chemisorbed onto the surface active sites of the sample surface. Ever increasing temperature is applied to the sample. At a certain temperature, the heat energy will exceed the bonding energy and the chemisorbed species will be released. If different active metals are present or if the active sites have more than a single activation energy, the chemisorbed species will desorb at different temperatures.
The desorbed molecules enter the inert carrier gas stream and are swept to the detector which measures gas concentration. The volume of gas desorbed combined with stoichiometric factors and the desorbing temperature yield the number and strength of the active sites. Temperatures exceeding 1100°C can be attained.
Temperature-programmed reduction determines the number of reducible species and the temperature at which reduction occurs. This analysis begins by flowing hydrogen, usually at 10% concentration in an inert gas stream, over the sample; the system is usually at ambient temperature. The amount of hydrogen consumed in reduction of oxide species with increasing temperature is monitored.
Temperature-programmed oxidation examines the extent to which a catalyst can be reoxidized. First, metal oxides in the sample are reduced to the basic metal with hydrogen. Then the reactive gas, typically 2% oxygen, is applied to the sample as a steady stream while the sample temperature is increased.
Again, the amount of oxygen consumed is monitored by the thermal conductivity detectors and quantified; these tests determine the extent of the reduction and the nature of the reoxidized species.
Temperature-programmed chemisorption reactions can be studied in greater detail by use of another Micromeritics instrument type. As in the instruments just described, reactive gas in an inert carrier stream flows over the catalyst sample after it has been outgassed, reduced, or otherwise prepared. Temperature- programmed desorption, reduction and oxidation studies are conducted as described before. This instrument design, however, permits testing from subambient to over 1000°C.
The significant difference between this instrument design and the one described previously is that operation of this latter instrument type is automated. The valves, detector, and other critical internal components of the analysis system are designed and engineered for minimum dead volume, maximum response, and high resolution.
Furthermore, by incorporating programmable heaters into the valves and internal gas lines, liquid vapors such as pyridine and quinoline can be used as chemisorbate probe molecules without loss due to condensation. This design feature also facilitates attaching a mass spectrometer or other external detector, thus permitting the identity of the reaction species to be determined. The latest model of this design is computer controlled from start to finish and results are reported as graphs and data tabulations.
The Micromeritics static volumetric chemisorption system is a version of the static volumetric physisorption unit noted in conjunction with surface area measurement.
When employed as a chemisorption analyzer, an accessory permits the sample to be prepared on the analysis port. This eliminates the necessity of moving the sample holder between preparation and analysis ports, which would expose the sample to atmospheric contaminants. Not only can this unit be used for surface area and pore size and volume distribution determinations, but it also determines automatically active metal surface area and percent metal dispersion for catalyst materials.
Preparation and analysis of samples are directed through a graphical user interface to the computer system. Sample preparation uses the flowing gas techniques with hydrogen gas, either pure or in an inert carrier, to reduce completely the oxides on the catalyst. Complete removal of residual hydrogen after preparation is accomplished by applying heat and a high vacuum. Analysis is made by the static volumetric technique to obtain precise dosing of the reacting gas and rigorous equilibration following the dose.
The first analysis measures both strong and weak interactions in combination. A repeat analysis after evacuation measures only the weak, or reversible, uptake of reactant.
Automatic data reduction provides complete information about active metal surface area and percent metal dispersion. An analysis log reports pressures, temperatures, and volumes chemisorbed plus an elapsed-time record for each data point. Plots containing both the initial and repeat analysis curves are generated. A difference plot shows the strong component of chemisorption. It is fitted to a single straight line for computations of a single uptake number and subsequent computation of the percent metal dispersion.
The prefix "nano" indicates a scale factor of 10-9(one billionth). A particle of nano size has at least one linear dimension in the nanometer range. Since it requires about 3 to10 atoms (depending on the element) to span one nanometer, a few hundred atoms is about the limit of the dimension of a nanoparticle.
Nanoscience seeks to gain knowledge and understanding of nanoscale phenomena, while nanotechnology employs this knowledge in the development of new products. These products can be improved catalysts or materials with enhanced strength, wear-resistance, corrosion resistance or high temperature endurance but, in general, they are materials with enhanced performance. On the whole, nanostructured materials are providing novel opportunities in wide range of scientific fields.
But, being of nanosize is not what attracts such great interest in nanomaterials, it is their properties. The properties of nanomaterials are different from those of the same material at the macro scale. When materials are reduced to sufficiently small sizes, typically less than 50 nanometers (a few molecules), novel physical, chemical, and biological properties arise that provide opportunities for new applications. Furthermore, these surface properties can be optimized for particular applications through molecular modification. The fundamental reasons for the changes or enhancements of characteristics are the increased surface-to-volume ratio and the increase dominance of quantum effects that determine the material's optical, magnetic, and/or electronic properties. Working with nanoscale systems requires special tools for manipulating, measuring and controlling size and properties. A different knowledge set also is required since nanoscale phenomena involve quantum mechanics rather than classical mechanics as is the case with materials of larger scale.
Micromeritics instruments have been used in the investigation of nanomaterials for over a decade. As previously discussed, pores are classified according to diameter where micropores have diameters less than about 2 nm, mesopore sizes range from about 2 nm to about 50 nm and macropores have diameters greater than about 50 nm.
In addition to pore volume distribution, total surface area also can be determined from gas adsorption. Not only does increasing surface-to-volume ratio enhance reactivity, as previously noted, it also enhances the efficiency of the material in trapping or storing adsorbed gases and vapors.
Being a nondestructive test, gas adsorption is the preferred method of determining pore characteristics and surface area of nanomaterials. However, mercury porosimetry also is capable of measuring pores of nano dimensions. At 30 kpsi pressure, mercury intrudes into pores of 5nm diameter and at 60 kpsi, pores of 2 nm can be probed.
For example, if the specific surface area of a mono-sized dispersion has been determined, the particle size of the material can be calculated provided that each particle is of the same regular geometry (typically spherical)l and without any porosity. The degree of crystallization of a material also may be inferred by comparing the measured density to the theoretical crystalline density of the material.
Recall that the sought after properties of nanoparticles are size-dependent and usually do not prevail until size has been reduced to less than 50 nm. While most of the novel properties are size-dependent, many of the common methods used for generation of nanopowders result in different size distributions. Not only is there need for tighter control of size in the production process, there also is need for a fast, high resolution method of measuring distributions in the lower end of the nanoscale in order to control production.
Fine particles play essential roles in determining the characteristics of both natural and manmade materials and have considerable influence on processes such as dissolution, adsorption and reaction rate. In the majority of cases, these effects are a function of either the size, shape, surface area or porosity of the individual particles or of an agglomeration of particles. These particle-related characteristics must be controlled in order to optimize the desired effects, and efficient control requires measurement. These same particle characteristics are either the causes of, the results of, or a determining factor in natural phenomena.
In this category, understanding or exploitation rather than control is more likely the objective and, again, measurements provide fundamental information used in achieving the objective.
As this article has illustrated, there likely are multiple techniques for determining the same particle dimension and each has its advantages and disadvantages.
Selecting a technique that is inappropriate for the application can have a profound impact on the quality of the measurement you obtain.
This information has been sourced, reviewed and adapted from materials provided by Micromeritics Instrument Corporation.
Micromeritics Instrument Corporation. (2019, December 09). Techniques for Determining Particle Size and Porosity. AZoM. Retrieved on February 23, 2020 from https://www.azom.com/article.aspx?ArticleID=3763.
Micromeritics Instrument Corporation. "Techniques for Determining Particle Size and Porosity". AZoM. 23 February 2020. .
Micromeritics Instrument Corporation. "Techniques for Determining Particle Size and Porosity". AZoM. https://www.azom.com/article.aspx?ArticleID=3763. (accessed February 23, 2020).
Micromeritics Instrument Corporation. 2019. Techniques for Determining Particle Size and Porosity. AZoM, viewed 23 February 2020, https://www.azom.com/article.aspx?ArticleID=3763.
In this interview, AZoM spoke with Damian Morrison, Director, Material Sciences at Waters Corporation, about emerging trends in the materials industry.
AZoMaterials spoke to Ben Melrose, Technical Director at International Syalons, about the grades of sialons that exist, why sialon is the answer to the problem of producing complex shapes with silicon nitride, and how International Syalons are providing the solutions to the challenges associated wi
This article, by thought leader Trevor Forster, Managing Director of Titan Enterprises, discusses a success story in flowmeters.
The PMV 50 is an advanced moisture analyzer solution that, when compared to standard moisture analyzers, shortens the drying time.
This page details the capabilities of the Kinexus DSR rheometer, a dynamic shear rheometer designed for routine analysis and QC testing in the Asphalt industry.
The PZ Series Triple Screw Pump is used for applications such as fuel oils and lubricants not containing solids.
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1000mm Graphite Electrode Products Made in China
Graphite Block, Graphite Crucible, Graphite Electrode - Laihao,https://www.hdslhmy.com/


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Simply apply two coats of your favourite Cheeky nail paint colour for maximum effect.
How To Use
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subset: commoncrawl


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>I have to tell you that we drive not one, not two, but three Toyota vehicles in our household. Yes, three. We have a Sienna (silver!), a 4Runner (green), and a 97 Camry (green) that is still going strong. I have to mention the colors, since we've never actually purchased a brand new car, we've never gotten to choose the color. As much as I love Toyotas, I'm really *done* with Toyota greens. (That's it, folks. My one beef about Toyotas). Since we buy used and people like to hold onto Toyotas forever and then some…there isn't a whole lot of selection when it comes to buying a used (pre-loved) Toyota.
As much as I love my minivan and have fun driving the 4Runner, I will always have a soft spot in my heart for the Camry. Its such a fun car to drive. So fun. The Camry was given to us by my in-laws before we were even engaged to help me not have a car payment and pay off my student loans. That car has been with Mr. Bargains and me since a year into our dating relationship, and its seen us through a trip wayyyyyyyyyyyyyy up north in Maine for white water rafting, trips to Boston for Pearl Jam concerts, visiting friends…trips to New Hampshire to see my parents, trips to the outlets (just so you know, my shopping friends…Camrys have a LOT of trunk space. Oodles of it.) and a million other places. We went house-hunting in our Camry, and went to all of my prenatal appointments with my oldest in that car.
The Camry is still Mr. B's choice for commuting to and from work- its a workhorse. The front wheel drive makes you feel really safe behind the wheel even during snowstorms. One of my favorite things about Camrys- all Toyotas, really- is how SOLID they feel. I've always felt safe in our Toyotas and continue to feel safe.
The Camry makes me feel safe, too, but it's also the one vehicle we have that doesn't have carseats installed in it, and has the most power- fastest pickup. I feel less like Mama and more like ME when I'm driving that car. Something about driving it makes me turn up the radio REALLY loud!!
There are over 130,000 miles on our Camry and at least that many memories we have in it!!
I'm participating in a Toyota/TwitterMoms campaign, which inspired this post. My opinions, thoughts and feelings are my own. As a TwitterMom, I'm eligible for a courtesy gift of $50.


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The image is overpowering. Leaning up against the 2011 Subaru Forester 2.5X in a car wash is a sumo wrestler, posing with his hand behind his head, wash-wand playfully pointed skyward.
In large pink lettering, with a font that looks as if it was made solely for exotic clubs is the phrase, "Sexy comes standard."
While Subaru deserves credit for its fun adverts, the idea conveyed isn't entirely accurate. The 2011 Forester doesn't make you swoon right off the bat. It didn't make me swoon, anyway. It's much tougher, though, to come up with an ad campaign that demonstrates how an averagelooking sport-utility vehicle with a forgettable, albeit functional interior can gradually win you over (try to incorporate a sexy sumo into that).
If purchasing a vehicle is about bringing home what you need more than what you want, the week I spent with the Forester 2.5X with Touring package hammered that point home. The Forester looks like your standard SUV in its exterior, feels like a roomy station wagon on the inside and performs somewhere in between when it's on the road.
The Forester boasts a 170-horsepower four-cylinder engine and 174 pound-feet of torque; the torque is an upgrade over the 2010 edition (170 lb.-ft.). Some reviewers have complained about a jumpy/jerky nature in the Forester, but it's only something to grow accustomed to with the vehicle. I found I didn't notice it after driving for a few days.
The Forester offers a smooth ride in town and on the highway, and with a plethora of space inside, it would be great for long trips or the daily hauls that families have to make.
The Forester is supposed to average 9.9 L/100 km in the city, but I was getting more in the range of 12 in the week I had the vehicle. The particularly frigid temperatures that week and the inefficiency of its new engine need to be taken into consideration, though. As the engine breaks in and the fuel efficiency gets closer to where it should be, the Forester will grow on you as you get to know it.
It's a comfortable ride in every way imaginable, from the heated seats (and 10-way electronically adjustable driver's seat) to the ease that you have in shoulder checking and backing up. The Forester has a throwback feel to it in that your behind-and-aroundyou views are basically unobstructed. It may be a simple observation, but it was nice to be more than mostly sure that I was safe to change lanes, or that there was nothing coming from my left or right while I backed up that I didn't see.
As much as the all-wheel drive aids the fuel needle in ticking away like a stopwatch, it's also reassuring and adds fun to the driving, especially in an Edmonton winter. The vehicle feels secure motoring over icy stretches of road and ice-rink-like parking lots, and its height is ideal for those random, merciless dumps of snow we've been prone to this winter.
These realizations, in my case at least, came with time. My first impression of the Forester wasn't great. Again, there's nothing wrong with the vehicle; it just didn't bowl me over with its esthetics.
It seems that Subaru didn't go out of its way to glitz the Forester up on the inside. The stereo is simple, and despite its diversity (MP3/ USB/auxillarycapable/statellite/ Bluetooth), if music is a part of your driving experience, you'll be upgrading quickly.
Even small things like the automatic locks are frustrating, forcing you to manually hit the button, as opposed to it locking once the vehicle reaches a certain speed or popping unlocked when you put the vehicle in park.
The console is as straightforward as you can imagine and the cupholders are unfriendly, taking form as two large, square-shaped openings between the seat that don't hold cups well at all.
With time, however, these are things you can get used to. Once you've adapted to the Forester, you start to realize just how compatible it is with this city, especially in the winter.
If you can stomach its appetite for fuel (cue that sumo again), the Forester does have its own unique sex appeal.
The Specs
2011 Subaru Forester 2.5X Touring
Type of vehicle: All-wheel-drive sport utility vehicle
Engine: 2.5L dual overhead cam (DOHC) four-cylinder Subaru Boxer engine
Power: 170 hp at 5,800 r.p.m.; 174 lb.-ft. of torque at 4,100 r.p.m.
Transmission: Five-speed manual
Brakes: (front): Four-wheel discs
Tires: 225/55 R17 95H Yokohama Geolander G95 M + S all-season
Price: $28,965 as tested
Destination charge: $1,525
Transport Canada fuel economy (L/100 km): 9.9 city, 7.6 hwy.
Standard features: Air conditioning with filtration, power windows, power locks, power moonroof, cruise control, cloth upholstery, 10way adjustable driver's seat, advanced AM/FM/CD/MP3/WMA audio system with four speakers, steering-wheel integrated audio controls, MediaHub for iPod/USB audio integration for Bluetooth streaming audio, two 12-volt outlets, outside temperature readout, variable intermittent wipers, keyless entry with panic alarm, remote trunk release, 60/40 split/folding rear seats, rear defroster, cloth upholstery, raised-profile roof rails; privacy tinted glass, driver and front passenger front and side-impact airbags; side curtain airbags with rollover sensor, anti-lock braking system, electronic brake-force distribution and brake assist


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A forum about Atari 16/32 computers and their clones. This forum is in no way affiliated with Atari Interactive.
Moderators: simonsunnyboy, Mug UK, Zorro 2, Moderator Team
peterlane wrote:Let me know if anything's unclear, or could be improved.
gstoll wrote:In open_vwork you must set work_in[2] to 2 + Getret(). ("work_in[10] = 2 + Getrez();")
qstoll wrote:https://github.com/petercrlane/sokoban/ ... /windows.c : event_loop
It is not necessary to make a #if for some messages. For example WM_SHADED is also pressend in MagiC or WINX.
peterlane wrote:I take it you mean work_in[0] = 2 + Getrez (); ?
peterlane wrote:I put the #if in as I have previously had problems compiling code with TOS 4 features on my STe.
gstoll wrote:Maybe you use floating point. The ST version from AHCC don't support them. With PureC you can use it.
peterlane wrote:Thanks for the suggestion. It prompted me to look again at the Atari Compendium, and I notice it says for work_in[0]: "For screen devices you should normally use the value Getrez() + 2, however, a value of 1 is acceptable if not using any loaded fonts"
I take it you mean work_in[0] = 2 + Getrez (); ?
(I admit, I took the code for open_vwork directly from CManShip and haven't questioned it.)
lp wrote:These off screen calls are pretty cool, but they don't seem to work on any machine using fVDI which drives graphics cards and some clones, like the FireBee.
jfl wrote:On the FireBee, NVDI runs and takes care of this. I know, it's confusing. I never could figure out how the VDI works on that machine
sashapont wrote:Are there any sample with creating windows from rsc dialog?
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Welcome to Affordable Learning Solutions (AL$)
CSU's Affordable Learning Solutions enables faculty to choose and provide more affordable, quality educational content for their students. By reducing CSU student course material expenses, more students acquire the course materials they need to succeed and benefit from their CSU learning experience. Now CSU faculty and students have greater access to quality free and lower cost learning materials through a variety of AL$ programs and partnerships.


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I'm sick of being discriminated against! Why Are Mountain Bikers Discriminated Against? There have to be 1,000 times more mountain bike owners than horse owners so why are there way more miles of trail open to horse users? In addition, a few bad apples among those .5 percenters who own horses manage to do 10 times the damage to trails as mountain bikers? Why isn't there an organization that fights against this discrimination?! I'm not one for frivolous lawsuits but this is a case where someone/group needs to take this to court! Why does such a small minority of trail users have more rights to our public land than we do?
"Tens of thousands who could never afford to own, feed and stable a horse, had by this bright invention enjoyed the swiftness of motion which is perhaps the most fascinating feature of material life". ~Frances Willard, How I Learned to Ride the Bicycle
Don't get me wrong, I love horses, they are beautiful creatures. I simply want equal rights with their owners.
Has anyone heard of a group that legally fights for mountain bikers? I used to give over $3,000 a year to a group that I thought did this but it turns out they have never filed a lawsuit. I'm sick of compromises where we give up existing, fun trails for the "right" to build new trails where we already had the right to build new trails. Anyone else fed up with this? Anyone want to file a lawsuit? I'm not a lawyer but I have $3,000 a year I will personally donate to this cause.


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TIST (tran)script
Text format by Svein Halvorsen (87k)
by Svein Halvorsen (30k)
PDF Acrobat by John Reynolds (159k)
A Chat with Spinal
1996 transcript from Hollywood Online
A Chat With Derek
Metal Edge magazine (January 2001)
Another Chat with
from Playboy.com
Bonnie Rose's Painful
Exclusive interview with former fan club president
Guitar World Interview
classic April 1992 interview with Guitar World
Ian Faith Lives!
He didn't croak after all (1992 article from Spy)
Nancy Bauer and Sean
Exclusive interview with two of the creators of the Criterion
edition of "This is Spinal Tap" (now out of print)
Nigel Tufnel Interview
Rare 1992 interview taken from Painful Procedure, the once-official
fan club newsletter
The Nose Interview
This interview, conducted in 1992, appeared in a humor magazine
published in San Francisco
Peter Occhiogrosso
Exclusive interview with the author of Inside Spinal Tap, the
official band biography published in 1985
Practice, Practice, Practice
An interview with the band on National Public Radio's "Weekend
Edition," June 2, 2001
Secret Spinal Tap Tapes Exposed!
Prior to their June 2009 appearance at Wembley Arena, the band
(along with TIST director Marty DiBergi) sat down for an interview
with Vanity Fair. You can listen to the audio or read the transcript.
Spinal Tap Sculptor
An exclusive interview with Mat Falls of Sideshow Toys, who sculpted
the Tap action figures
Viv Savage Lives!
This interview with the former Tap keyboardist first appeared
in the Nose, a humor magazine.
Action Figures in
Cosmic Shambles offers five of her 67-image collection of the
Spinal Tap dolls in repose. Warning: One photo is particularly
Concert Photos
exclusive photos from 1984 Chicago performance
every album that goes to 11
Frequently Unasked Questions (FUQ)
maintained by Joe Blevins and updated monthly
I'm With the Band
an exclusive list of every member of Tap
Lost Footage
a description of the best scenes from the 4.5-hour director's
cut of This is Spinal Tap
Meet the Artists
Stagebill bio from 2001 Carnegie Hall show
Mockumentaries Galore
other movies that Tapheads will enjoy
Official History
from the Break Like the Wind press kit
Painful Procedure
download the 1992 official fan club newsletter
Tap on Marty "The
Butcher" DiBergi
bitter afterthoughts from the band, from the former official
fan club newsletter, Painful Procedure
Tap Timeline
exclusive run-down of Tap's history
Thoughts on Tap
thoughts and comments posted to alt.fan.spinal-tap
More Thoughts on Tap
thoughts and comments sent to the fan site
Unconfirmed Rumors
posted at the official site
ABCs of Spinal Tap
An homage to Tap from More Luv Letters: Star Poems by the Readers
of Teen-o-rama
History of the
by Ethan de Seife / University of Wisconsin
see also The
Mockumentary Cometh (Salon.com)
see also Mockumentaries Galore (list)
It's Spookily Familiar
thoughts on Tap from famous rockers
Nigel Tufnel Guitar
classic 1992 feature from Guitar World magazine
Nigel Tufnel's
Guitar Collection
classic 1992 feature from Guitar World magazine
Origins of Stonehenge
Ian Gillan of Black Sabbath explains how his band came up with
the idea of doing a Stonehenge show
Scene Report: Los
Reports from the front row of the Los Angeles concert, September
5, 2000
Scene Report:
Back From the Dead
Reports from the road, Summer 2001
Spinal Tap: Absolution
for Rock n' Roll? Or Just Another Media Gimmick?
Hugh Asnen explains Tap's confirmation of the ideas of social
theorist Walter Benjamin
Stylistic Competencies,
Musical Humor, and This is Spinal Tap
Music professor John Covach of the University of North Carolina
contributes an insightful analysis of Spinal Tap's greatest hits
Tap on the Bitch School
the boys explain exactly what they meant with this controversial
This One Goes to 11
Philip Ball reports in Nature on how heavy metal music can physically
move its fans
Trivia Quiz
rate yourself as a Taphead
search for "Spinal Tap," by Barry Weber
Making Time: Guide to '60s British Music
the entry for Spinal Tap
Rocklopedia Brittanicus
the entry for Spinal Tap
Spinal Tap A
to Zed
550+ entries about the band
Discussion & Reviews
This Usenet discussion group averages about five new messages
a day. I have collected a number of great
thoughts and comments over the years. Before you post, check
out the Frequently Unasked Questions compiled by Joe
Blevins, which is posted to the group on the 11th of each month.
If you can't reach the newsgroup through your ISP, visit via
Google's Deja service. It also holds the earliest
known Usenet reference to Spinal Tap, from 1984.
Official Tap Announcement List
If Tap has anything to say, this is the place they'll say it.
Rate This is Spinal Tap
at the Internet Movie Database
Rate The Return of Spinal Tap
at the Internet Movie Database


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Advance Tabco is the ultimate destination for high-quality stainless steel products. From worktables to sinks and dish tables, Advance Tabco uses high-grade stainless steel to construct equipment that will last and prove durable in the most rigorous institutional settings. Advance Tabco is also proud to offer a great custom program with their Build-A-Table and Build-A-Sink systems which allow you to build your work table or sink to fit the exact specifications of your venue.


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Divorce topic page
Here are some helpful Divorce resources from our site. You may also visit our Law Library to find more information.
- What is a Divorce?
- Who Can Ask for a Divorce in Kentucky?
- Do I Need a Lawyer to Ask for a Divorce?
- How do I Ask the Court for a Divorce?
- Property and Debt in a Divorce
- Some Tax Implications of Divorce
- Tax Information for Innocent Spouses
- More information on divorce
Self-help divorce options:
Self-Help Divorce Forms. Online divorce forms now available for statewide use in Kentucky.
Selected Jefferson County Forms. These may be useful if you have been granted a divorce in Louisville-Jefferson County AND are interested in contempt orders or in modifying child custody, primary residence, child support, and visitation.
En español: El divorcio en Kentucky
Sometimes the laws change. We cannot promise that this information is always up-to-date and correct. This is general information only, and we do not guarantee its accuracy. If you need legal advice you should consult with an attorney.


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Earlier today we got our first look at a crazy Matthew Fox in the James Patterson adaptation Alex Cross, but now we've got some images of Fox being somewhat normal-looking in director Peter Webber's (Girl with a Pearl Earring) historical drama Emperor. The film takes place during the days following the Japanese surrender at the end of World War II and stars Tommy Lee Jones as General Douglas MacArthur, the de facto ruler of Japan as Supreme Commander of the occupying forces. Fox plays a leading Japanese expert on the staff of MacArthur who is tasked with deciding whether or not Emperor Hirohito should be tried and hanged as a war criminal
These first images and sales posters aren't anything mind blowing, but it's pretty cool to see Jones sporting McArthur's ginormous pipe. Hit the jump to take a look.
Here's the synopsis for Emperor:
Inspired by true events, EMPEROR is an epic story of love and understanding set amidst the tensions and uncertainties of the days immediately following the Japanese surrender at the end of World War II. On the staff of General Douglas MacArthur (Jones), the de facto ruler of Japan as Supreme Commander of the occupying forces, a leading Japanese expert, General Bonner Fellers (Fox) is charged with reaching a decision of historical importance: should Emperor Hirohito be tried and hanged as a war criminal?
Interwoven with this nail-biting political thriller is the story of Fellers' love affair with Aya, a Japanese exchange student he had met years previously in the U.S. Memories of Aya and his quest to find her in the ravaged post-war landscape help Fellers to discover both his wisdom and his humanity and enable him to come to the momentous decision that changed the course of history and the future of two nations.
Images and posters The Film Stage:


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Because planking is so last week
planking") is the art of doing a plank, putting the picture of said plank in Photoshop, and using an elementary understanding of the program to create a plank of epic proportions. Sure, we made this up. But if taking pictures of people laying face down and motionless can take the world by storm, imagine what spiffier pictures will do?
As for planking, further research has clued me into its origins. While it's widely held that the fad was started almost 15 years back by a couple British dudes, the Alibi unearthed the fact that it was actually started by the mighty elephant seal, which spends the majority of its life planking. ... Although they could be a little more creative with it:


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We have been hearing more stories than usual about the frustrations of online travel engines' customers lately. In addition to horror stories we have read about, two people we know faced dropped bookings when they arrived at the airport.
One had booked a flight and the other a whole vacation package and both were told that there was no record of payment (even with a confirmation number!) and they would have to pay for their trips again.
The details of their efforts to recoup their cash after the trip are a nightmare of frustration, inept and rude customer service and stonewalling. One story stretched over several months.
So we were not especially surprised when we saw the report by eMarketer (they sell market research and trend analysis about Internet commerce) about the decline in the number of people booking online and the increase of people booking through travel agents.
An indication of how fed up people are with online booking engines is websites that will refer you to a vetted travel agent who can then help you book your trip. Zicasso.com (www.zicasso.com) and Tripology (www.tripology.com) both have generated good P.R. by taking business away from the online booking engines.
Their service is a cross between booking online and having a qualified travel agent help you. After you fill out a form with the details of your trip, you receive a no-obligation quote in a short time. (Note that if you book online through a non-B.C. travel agent, you probably will not be covered by the B.C. Travel Assurance Fund.)
Booking through a travel agent is some of the best insurance you can buy. When problems arise, you have someone to call. You can go and have a coffee while they sort out the problem. If they can't fix it right then, you'll at least know that when you return from your holiday, your travel agent will probably have fixed the snafu.
In British Columbia every travel agency must be registered with the provincial government that oversees the Travel Assurance Fund set up to reimburse you for travel company bankruptcies and non-performance.
If you live in B.C., you can check if your travel agent is registered by typing in the agent's registration number at www.bpcpa.ca/index.php?-option=com_licensesearch&Itemid-=138&task=active_bus.
Barbara Braidwood and Rick Cropp are Vancouver-based writers.


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What is an average day at the University at Buffalo? There really is no such thing. With more than 300 academic, cultural and recreational clubs to choose from—plus lectures and faculty presentations, outdoor movie nights, performing arts and so much more—your day can be anything but ordinary. Plus, our 20 NCAA Division I sports teams will have you showing your True Blue spirit.
What do you feel like doing today? No matter what it is, there's a good chance we have an event that matches your interest. You can do a lot of things at UB. We assure you that being bored isn't one of them!
Our students are a diverse group of people with many different interests. You'll find evidence of this diversity in the more than 200 clubs and organizations you can join on campus. These include fraternities and sororities, along with clubs that are specifically geared toward international students.
Welcome to Bulls territory. UB has 20 NCAA Division I athletic programs, many of which have long and storied traditions of success, from a football program that has produced numerous NFL players, to a women's rowing team that has won some of the nation's most prestigious regattas.
If you're looking to try a new sport when you arrive on campus, or just want to get fit or stay in shape, UB's Alumni Arena is the place to be. Students have free use of the facility's weight room, Olympic-sized swimming pool and various athletic courts. You'll also find a range of on-campus programs that promote health and wellness, including intramural football (soccer) and yoga and cooking classes.
What do Arnold Schwarzenegger, former U.S. President Bill Clinton, Katie Couric, Jane Goodall and Stephen Colbert all have in common? They're among the dozens of world-renowned speakers UB has hosted over the decades as part of its hugely popular Distinguished Speakers Series.
Enthusiasm for our undeniable cultural diversity is what makes UB such a welcoming place. You won't have any trouble finding an international-themed event happening on campus, from our annual International Fiesta and International Education Week to our multicultural bazaars.


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Spanish supermarket chain Eroski moves
decisively towards efficient logistics. In the last four years, their initiatives have led to 30% less transport kilometres, faster circulation of products, 15% labour savings, less mistakes and better product quality. "Euro Pool System has bridged the logistic knowledge gap for us," says Imanol Alberdi Uria Logistic Director of Eroski's Distribution Centres (DC).
In June 2010, the Spanish supermarket chain Eroski became the first in Spain to start using an automatic order-picking system of this kind for its fresh products.
The order-picking operations take place in Madrid's 28,000-m2 consolidation centre. A unique cooperation initiative realised by Eroski, system integrator Ulma Handling Systems and logistic service provider Euro Pool System. It's the latest move in the logistic revolution of the Spanish supermarket chain. It all started twelve years ago when Eroski chose Euro Pool System's multi-way crates to standardise their containers for fresh products. Between 1998 and 2010, the number of rotations in the green and blue foldable crates grew from 250,000 to no less than 50 million a year. All meat, fish, fruit and vegetables, and bakery products suppliers pack their orders in multi-way crates now. That was just the first step.
Four years ago, the second step followed. Imanol: "We centralised our fresh product flows via Madrid. Before, hundreds of suppliers actually delivered their products to ten regional distribution centres, while 80% of those logistic flows went through Madrid. It could be done more efficiently. Centralising allowed for clear improvements: from ten orders to one, from ten invoices to one, and from ten quality controls to one. Moreover, we reduced our transport kilometres by 30% and shortened product storage from 1.2 days to 0.3 days." Eroski realised that having one central consolidation centre for all fresh products was a risky move and that's why Euro Pool System has its service centre just next to it. There, all crates are washed, stored and distributed. The service centre is equipped with cold storage facilities. "In case of need, the service centre operates as back-up for our consolidation centre ensuring the continuity of our activities," explains Imanol.
The back-up system proved its worth when step three was set into motion in the spring of 2010. Euro Pool System's service centre was used as consolidation centre while the automatic order picker was being installed. In June, the automatic order picker became operational, and by September it will be working at full capacity. "Its maximal capacity is 150,000 crates a day. Because we are operating as consolidation centre, 65% of the supplies are shipped out as full pallets and 35% are re-distributed and later completed at the regional distribution centres," explains Imanol. From the buffer storage, with its impressive 800-pallet capacity, the shuttles move complete pallets automatically to the selected conveyor belt where they are
prepared for shipment. The multi-picker processes the other part of the pallets. The other pallets are divided according to their barcodes, placed on the orderpicking area, reorganised in full pallets and sent via the shuttles to the selected conveyor belt. And it's not even what you would call hectic, because the orderpicking processes are very steady and fast. Imanol:
"Thirty order pickers have made way for five process guides. The other employees can now do less heavy jobs and carry out qualitatively better work. There are less mistakes, product quality is preserved and the whole process is much faster."
The automatic order picker is the first of its kind in Southern Europe. Without the close cooperation between Eroski, Euro Pool System and Ulma, this innovative move wouldn't have been possible. Imanol: "Euro Pool System already had proven experience with automatic order pickers for fresh products with its customers in Belgium and the Netherlands. Our conversations also made it clear to us that Euro Pool System wanted to expand its service providing activities. We now rent the automatic order picker from Euro Pool System. We have entered a new era of collaboration: Euro Pool System has become a bridge to logistic knowledge and a bridge between Southern and Northern Europe." The automatic order picker isn't the last innovative step towards logistic efficiency though.
Imanol: "The next step will be automating the orderpicking activities at our regional distribution centres.
And we are also going to work together with Euro Pool System to this end. We truly trust each other."
Also visit www.eroski.es, www.ulma.es and www.europoolsystem.com


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In a move not unlike the "Send2Car" feature on the Dash Express GPS navigator, Garmin has worked it so that people using Google Maps and MapQuest will easily be able to send the address they're looking at to their navigator, to avoid typing it in all over again.
Google's will be available starting tomorrow; the MapQuest version (explained here and shown above) will launch later in the month. Of course, for the time being this will require a USB connection—unlike the Dash, which does it all wirelessly—so to call this process "hassle free" would be giving it too much credit. We still expect the nuvifone will be the real answer to all our Garmin-related prayers. In case this sounded familiar, TomTom already has an identical Google Maps feature. [Google Press Release; MapQuest Press Release]


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1. Use vertical space
After talking with lots of Tiny House folks, I have seen this as a trend: maximize the vertical. Everything above 8 feet is all dead air if you don't use it, so capitalize on that. You could have a small chest that takes up 2 square feet of floor space. If it is 4 feet tall, you will have around 8 cubic feet of storage. Take that to the ceiling and suddenly you have doubled or tripled your volume, but haven't given away any more floor space which is a scarcity in a Tiny House.
2. Everything has a place and is in its place
When working with a small space I know that everything needs a place. Without it, your house goes from quaint to cluttered. Make sure every item you have has its own resting place and be sure that it finds its way back once you're done using it. One lady who lives in a 90 square foot apartment said to me "if it doesn't have a place, do you really need it?" and that's a good point. Things that matter and are used are important enough to demand a place.
3. Double duty on items
There are those items which are by their nature, multi functional. You need to capitalize on these types of items. When you consider an item, you should always think if there is something else that can do it already. A perfect example of this is the end table, which transforms to a chair for extra seating. Check it out here.
4. Purpose built – built ins
Built-ins are nice, but built-ins with a purpose are even better. Think specifics. When paring down your possessions, you will identify the 100 or so items that will be contained in your house. Take stock of those items and let them dictate the form of your storage. If you are a ski patrol member, your closet should be able to fit your skis. If you live in colder climates, you will need more room for larger jackets than others might.
5. Go digital / paperless
As if being greener isn't motivation enough, going digital, as I call it, means that you are able to reduce the tangible items you need. Digital files take up no space if you have them stored online, with the added advantage of being able to access them from anywhere. Combined with backing the files up, they become safer than real world things. The IRS officially accepts all scanned copies of receipts and bank statements. This extends beyond receipts: books on your Kindle, movies on your Roku, music on OpenTape, or recipes in a wiki.
6. Less is more
At this point I am preaching to the choir but, the question is not how to organize all your stuff, but on how to reduce the stuff to organize. The mentality needed is the same as you had if/when you went to college. The dorm rooms were tiny and you were broke. You only had what you really needed. Studies have shown that more stuff does not lead to happiness, so focus on the important things in life.
7. One thing in, one thing out
One principle that I like to pull from the Zen/Fung Shui school of thought is this. If you want to add a new item, consider adopting the rule that for every item you bring in, you must give up something else. Now, no cheating – like giving up a pen for an arm chair, but you get the idea. 8. Be intentional Living with intention will have a profound impact on your life. Be thoughtful in your actions and choices. This extends to your organization and stuff. When you consider purchasing an item, you must first evaluate it and decide if you really need it. I often don't buy it right then, but next time I am in that store (in a week or two). If I still want it then, I usually go for it if it makes sense.
9. Think inside the box
This is a technique that I use when I feel that a certain space is cluttered or if I start stacking stuff. Take a box, fill it up with everything. Then as you need the items pull them out of the box. Six weeks later, if you still have stuff in the box – no, let me rephrase that, you WILL have stuff in the box – you can evaluate what is left. There is rarely an item that I have that I don't use within 6 weeks that's worth keeping. Detailed box theory.
10. Most used items easy to access
This seems pretty obvious, but having the most used items in the front means you are able to access them quicker and without disturbing other things. This ties back to being intentional. You should be intense about organizing your items in this manner. If you notice that there are items in the back that haven't been touched in a while, it's time to evaluate whether you still need them.


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Description: [Captain Jack] -
feat. DJ Tek
Hiho Hiho
It's off to work we go
Sweat in the sun - then have some fun
Hihi Hiho Hiho
Hiho Hiho
It's off to work we go
We do our best - and work for less
Hihi Hiho
Let's sing this song - hey
Let's sing this song - hooh
We're going on, com'on now
Look at me, I work so hard
And I don't really make a lot
Everyday oh I break my back
Outside and it is very hot
Oh why my life must be this way
I have no time to go and play
Oh I can't wait until friday
Then I can go and spend my pay
Back again I'm in the job
Doing what I did the week before
Look at me I work so hard
And my hands and feet are very sore
Who says my life should be this way
I have no time to go and play
Oh I look forward to firday
Then I can sleep my life away
Typed from the lyrics booklet for Dancemania Speed Best 2001
Contributed by Allen Tyner <[email protected]>
[Submit an English translation for this song]
See an error in these lyrics? Let us know here!
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My Little Pony Ties
Lyrics copyright to their respective owners or translators. No copyright infringment is intended or implied.
Layout and other content copyright Anime Lyrics dot Com / Anime Globe Productions
This is some text here


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- Home
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- Contact Us - How to find Master Gardener Help
- Who Are Master Gardeners and What Do They Do?
- Want to be an Alameda County Master Gardener?
- Outstanding Plants for Alameda County
- Demonstration Gardens
- Growing Your Own Food
- Plant Pests and Diseases
- Home Agriculture News and Updates
- Master Gardeners In The News-Articles By Master Gardeners
- Alameda County School and Community Gardening
- Collaborators and Community Resources
- Media Information
- Master Gardener Login
UC Master Gardener Program of Alameda County Calendar
Event Details
This event has been removed from the site.


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VirtualBox 4.0.8
Host: Mac OS X
Guest: Windows XP
Wi-Spy model: DBx
Chanalyzer: Pro
Thanks to Wi-Spy user Rod for documenting his experiences and allowing us to post his notes for others. These aren't step-by-step instructions, so please read the whole post before starting.
I had found something similar to these about the vboxuser but that article made it sound like the account/group should already exist which of course it doesn't.
So I tried the process on the*link you sent*and had no luck with getting the Wi-Spy to become "available" by adding a group and trying to change permissions but down in the comments of that same page is someone that had no luck either but found a solution:
'I found by removing in the USB-filter all info except the Product Name, Vendor ID and Revision and replugging, it works!'
So I removed the vboxusers group and created a new USB filter in vbox and filled in the 3 items mentioned above (as letting vbox auto populate them and then removing the extra data failed too) and then unplugged and plugged back in the adapter and boom...all is good.
Hello again,
I thought I had figured out the issue with the way to add the USB filter but I was mistaken. I wanted to correct my findings in case you find this useful with any other customers.
Actually, vbox has an issue with using more than 1 cpu in a WinXP (maybe other versions too, did not test more than XP) that causes USB issues.* As soon as I went down to 1 cpu I have had USB drives and the Wi-Spy device all work after any number of reboots, shutdowns, device removals (not the case running 2 cpus in vbox).
The only thing that happens like clockwork is this:* When I first plug in the Wi-Spy, Vbox sees it, I launch Chanalyzer, the app instantly crashes with a windows message "want to send a report...", then the USB icon starts flashing with crazy activity, then I know it is ready to launch Chanalyzer again without issue.* I have not got around the first launch-crash-re-launch combo yet, but at this point I dont care because it works in the end.* I can wait for a while and the icon never triggers activity for me until I try to launch the app to start the ball rolling.
I followed this test up on another laptop with the same version of Vbox running (4.0.8), and the same XP completely updated.** This extra test was to prove/confirm that I did NOT need to create the vboxusers group, add my account to it, change permissions for the USB functionality to work with the Wi-Spy device.** Both my systems work the same, with and without the whole vboxusers group steps.
So all-in-all I only had to make a vbox usb adapter filter, make sure I was using 1 cpu in the VM setup, and connect the device once the VM loaded.


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Online Learning
Things to know about online classes
Online classes are not self-paced. Students are required to participate regularly. As with face to face classes, online sections have assignments, quizzes and exams. It is important for students to meet deadlines, and the class follows the regular semester schedule. The primary difference between online and face to face instruction is that classes take place within a learning management system (LMS). CCSF uses a system called Canvas for most of its online instruction.
Check here for a list of online classes that meet transfer and graduation requirements: Transfer List/Graduation Requirements (PDF)
Learn more about online classes at CCSF.


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Welcome to the web-site of author, life-coach, and spiritual
leader Grant Schnarr. Here you will find a guide for
life, including spiritual growth, recovery, renewed faith, warrior
wisdom, humor, and adventure.
Grant's personal mission is to wake
people up to the fullness of life, love, and the Source of
all that is, through teaching, leading, mentoring, and walking that
path of spirit himself.