text: UFDC Home myUFDC Home | Help | RSS Group Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings Title: P1.74 - Lagrangian Stochastic modeling of gas-solid flows with two-way coupling ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE Full Citation STANDARD VIEW MARC VIEW Permanent Link: http://ufdc.ufl.edu/UF00102023/00465 Material Information Title: P1.74 - Lagrangian Stochastic modeling of gas-solid flows with two-way coupling Particle-Laden Flows Series Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings Physical Description: Conference Papers Creator: Zeren, Z.Bédat, B.Simonin, O. Publisher: International Conference on Multiphase Flow (ICMF) Publication Date: June 4, 2010 Subjects Subject: Lagrangian stochastic modelLangevin equationtwo-way coupling Notes Abstract: Two Langevin equations are proposed to model the particle-laden flows where the carrier phase's structure is modified by the solid uniform property particles. The first equation is the one taking into account the changes in the fluid velocity along the fluid element trajectories and the second equation takes into account the fluid velocity along the particle trajectories. The equations are the same as the ones proposed by Simonin et al. Simonin, O., Deutsch, E. and Minier, J.P., Applied Scientific Research, vol 51, p275-283, 1993 except an additional term to take into account the two-way coupling effect. The additional term is modeled in terms of mean drag from the mean transport equations of both phases. The model is compared to the DNS simulations corresponding to homogeneous isotropic turbulence kept stationary with stochastic forcing. Results showed that the mean drag term provides results in good agreement with the DNS results implying that the mean drag model takes into account the particle dispersion using the fluid statistics seen by the particles. However, the fluid statistics seen by the fluid elements are sensibly different than the fluid statistics seen by the particles which requires further consideration for adequate physical modeling. General Note: The International Conference on Multiphase Flow (ICMF) first was held in Tsukuba, Japan in 1991 and the second ICMF took place in Kyoto, Japan in 1995. During this conference, it was decided to establish an International Governing Board which oversees the major aspects of the conference and makes decisions about future conference locations. Due to the great importance of the field, it was furthermore decided to hold the conference every three years successively in Asia including Australia, Europe including Africa, Russia and the Near East and America. Hence, ICMF 1998 was held in Lyon, France, ICMF 2001 in New Orleans, USA, ICMF 2004 in Yokohama, Japan, and ICMF 2007 in Leipzig, Germany. ICMF-2010 is devoted to all aspects of Multiphase Flow. Researchers from all over the world gathered in order to introduce their recent advances in the field and thereby promote the exchange of new ideas, results and techniques. The conference is a key event in Multiphase Flow and supports the advancement of science in this very important field. The major research topics relevant for the conference are as follows: Bio-Fluid Dynamics; Boiling; Bubbly Flows; Cavitation; Colloidal and Suspension Dynamics; Collision, Agglomeration and Breakup; Computational Techniques for Multiphase Flows; Droplet Flows; Environmental and Geophysical Flows; Experimental Methods for Multiphase Flows; Fluidized and Circulating Fluidized Beds; Fluid Structure Interactions; Granular Media; Industrial Applications; Instabilities; Interfacial Flows; Micro and Nano-Scale Multiphase Flows; Microgravity in Two-Phase Flow; Multiphase Flows with Heat and Mass Transfer; Non-Newtonian Multiphase Flows; Particle-Laden Flows; Particle, Bubble and Drop Dynamics; Reactive Multiphase Flows Record Information Bibliographic ID: UF00102023 Volume ID: VID00465 Source Institution: University of Florida Holding Location: University of Florida Rights Management: All rights reserved by the source institution and holding location. Resource Identifier: P174-Zeren-ICMF2010.pdf Full Text 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 Lagrangian Stochastic modeling of gas-solid flows with two-way coupling Zafer Zeren~t, Beno~it B~dat~t and Olivier Simonin~t University de Toulouse; INPT, UPS; IMFT; 31400 Toulouse, France t CNRS; Institut de Mecanique des Fluides de Toulouse; 31400 Toulouse, France zeren~imft.fr, bedat~imft.fr and simonin~imft.fr Keywords: Lagrangian stochastic model, Langevin equation, Two-way coupling Abstract Two Langevin equations are proposed to model the particle-laden flows where the carrier phase's structure is modified by the solid uniform property particles. The first equation is the one taking into account the changes in the fluid velocity along the fluid element trajectories and the second equation takes into account the fluid velocity along the particle trajectories. The equations are the same as the ones proposed by Simonin et al. [Simonin, O., Deutsch, E. and Minier, J.P., Applied Scientific Research, vol 51, p275-283, 1993] except an additional term to take into account the two-way coupling effect. The additional term is modeled in terms of mean drag from the mean transport equations of both phases. The model is compared to the DNS simulations corresponding to homogeneous isotropic turbulence kept stationary with stochastic forcing. Results showed that the mean drag term provides results in good agreement with the DNS results implying that the mean drag model takes into account the panticle dispersion using the fluid statistics seen by the particles. However, the fluid statistics seen by the fluid elements are sensibly dif- ferent than the fluid statistics seen by the particles which requires further consideration for adequate physical modeling. Nomenclatu re Introduction Two-phase flows are important in terms of many indus- trial and natural processes. Among many different pos- sibilities of two different flowing matters moving cor- related to each other, solid particles in a turbulent gas flow receive much attention from the academic and in- dustrial partners. Different physical phenomena occur during these complex motions related to a particular flow considered. Interactions between the particles, interac- tions between the fluid and the particles form diversity of problems that can be encountered. In comparison to the other physical mechanisms, the two-way phase interactions are relatively less under- stood. Interactions between the fluctuating velocities of the phases, especially in presence of a mean motion, are very complex in terms of "what scale of particles' collective motion effects what scale (or scales) of the fluid turbulence", that the momentum transfer between the phases, probably, does not depend on specific parti- cle parameters but depends on other parameters such as initial conditions of turbulent field (Simonin and Squires 2003). This scale way of thinking in turn calls for spectral analysis that has been a widespread method of explain- Roman symbols fi Force acting on fluid due to particles Fi Turbulence forcing q2 Fluid kinetic energy ql Fluid kinetic energy seen q" Particle kinetic energy qf Fluid-particle covariance uf< Instantaneous local fluid velocity SStochastic particle velocity Uf~ Mean fluid velocity Instantaneous fluid velocity seen SInstantaneous particle velocity UMean particle velocity Vd1 Fluid-particle turbulent drift velocity Greek symbols Particle volumetric loading Particle mass loading Turbulent dissipation rate Two-way coupling term of Langevin model 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 source approximation to take into account the effect of the particles on the fluid turbulence. Turbulent flow is homogeneous and isotropic kept stationary with the stochastic algorithm of Eswaran and Pope (1988). A pri- ori tests showed that the modeling the two-way coupling term using the mean drag force produces accounts accu- rately for the particle dispersion modeled using the fluid statistics seen by the particle phase. Direct numerical simulation (DNS) and Lagrangian particle tracking (DPS) Turbulence simulation and characterization of the flow. Precise computation of the particle trajectories de- pends on the accurate prediction of the fluid statistics at the particle position. In this work, the focus is on the dynamical evolution of a particle cloud formed by N, number of inertial particles in a turbulent flow where the particles interact with the turbulent eddies and modifies their cascade of energy. To this purpose, Direct Numer- ical Simulation (DNS) method will be used which pro- vides the information about all the scales of turbulent flow. Thus comprehension and true modeling of the two- way coupling mechanism is more feasible with DNS due to the fact that the range of fluid scales influenced by the particles is not known a priori. DNS performed in this study solves the non- dimensional compressible unsteady Navier-Stokes equa- tions along with the continuity equation written as: ing the phase interactions. Many works were reported so far focusing on spectral analysis in order to understand the mechanism of two-way coupling as a function of par- ticle inertia, mass loading etc... Among these works, we can cite the works of Squires and Eaton (1990), Elgob- ashi and Truesdell (1993), Boivin (1998). The main re- sult according to these studies is that highly inertial par- ticles have more uniform modification on the turbulent energy spectrum; on the other hand, low inertia particles have more non-uniform modification of the spectrum. One efficient method to investigate the phase interac- tions is to use Lagrangian stochastic approach, which is a powerful tool and largely used in statistical physics to simulate random processes. Langevin equation, the simplest stochastic model equation, has received much attention not only in gas-solid flows but also in other do- mains such as combustion. Its one of the advantages is the easy adaptation to the inherently Lagrangian motion of discrete particles and fluid elements. In this work, the focus is on the modeling of gas-solid flows using stochastic Langevin equation in presence of particles smaller than the Kolmogorov scales. Particles are of uniform property, spherical in shape and inde- formable. Volumetric loading of particles <1, is very low so that the particle-particle interactions are not taken into account. However, mass-loading of particles 97, is con- siderably high that the fluid turbulence structure is mod- ified significantly. Lagrangian stochastic method was developed initially for monophase flows in which the trajectories of fluid el- ements are modeled using stochastic Langevin equation (Haworth and Pope 1986). These fluid element trajecto- ries are perturbed by the effect of particles in two-way coupled gas-solid flows which should be taken into ac- count properly. Langevin equation was also shown to provide the unperturbed fluid velocity at particle posi- tion which is required to calculate the drag force (Si- monin et al. 1993). This fluid velocity is unperturbed by the presence of particle in question, however, it is mod- ified by all the other particles of the system. Therefore two equations of Langevin type are proposed where the originality is an additional term, which accounts for the modification of the fluid velocity by the effect of sur- rounding particles. First equation is to simulate the tra- jectories of fluid elements and the second one is to sup- ply the fluid velocities experienced by particles during their trajectories. Because of the lack of the spectral un- derstanding of two-way coupling mechanism, the form of the two-way coupling term should be imposed prop- erly. Additional two-way coupling term is modeled using the mean drag force. Model results are compared to the DNS simulations corresponding to the solution of Navier-Stokes equations written in the frame of the point 8~ 8.r; ~= 0 (1) 8p? 1 8 8.r; Re, dze.32 + fe, + F,,, (2) Sdt fi S z /it/ + where p is the density of the gas, p is pressure and fe, is the force acting on the fluid due to the presence of particles which will be modeled later on. F,,, is the turbulence forcing term to obtain statistically stationary flow. Re ac is the acoustic Reynolds number based on the speed of sound. The turbulent Reynolds number Re L Of the flow defined as: U 3 Re L Vf where vf is the kinematic viscosity, Lf is the length of the large scales, u is the characteristic velocity of tur- bulence where qy is the fluid turbulence kinetic energy defined as: 97 = d' ,i; "7, 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 takes into account the effect of a particle on the short and long range turbulent fluid flow. Koch (1990) showed that in Stokes' regime only the long range interactions are important reducing the Point Source approach to only the monopole force. This is written as: where (-) is the ensemble average operator. These defini- tions are proper to the homogeneous isotropic turbulence which is the turbulence conducted in this study. The balance equations are solved using the in-house code called NTMIX3D which is a finite difference base code. It solves time dependent, three-dimensional mo- tion of fluid turbulence in a Cartesian geometry using the 6t" order compact scheme developed by Lele (1992) for the space derivatives. Time advancement is obtained using 3rd order Runge-Kutta scheme. Flow is solved on 1283 grid in a cubical domain whose one side is Lb = 2x7. Periodic boundary conditions are used at the boundaries of the cube. fui = F6x where F )du () 7,s m(" di . n this work, parti- and 6(x) is the Dirac delta function. in shape, all with the The application of the point source approach in a DNS .Particle diameter is code considers first, the calculation of the drag force at Scales of the flow: the particle position by interpolation the fluid velocity to this position and then opposing this force in sign and (4) projecting back onto the 8 Eulerian grids surrounding nterctios de tothe the particle. These projections could cause the fluid ve- locity at the position of the particle n to be perturbed by ,rces acting on a parti- the particle resulting in a bias of drag force which Each particle is time is based on the unperturbed fluid velocity by the exis- ns: tence of particle. This can be validated by a simple P,i(t) test using two populations of particles (Vermorel et al. di Up,s (t) (5) 2003). One of the populations is two-way coupled and the other group is one-way coupled (so-called ghost par- .* ,, p~i) (6) ticles). Then fluid-particle covariance of the two groups is compared to each other. This test controls simply that Article, xp,4 is the posi- whether the fluid velocity at the position of the parti- ,, is the density of the cle is perturbed by all the particles of the system includ- It. For Re, < 1000, it ing particle. As shown in figure 1, for the most critical simulation performed in this paper (~ = 1.32 and 7, = 3.0), the dp IPVr 7 statistics between the two groups is different to a %b 1 Vf error margmn validating the point source approach. Particle trajectory computation cles are accepted solid, spherical same diameter d, and density p, very small before the Kolmogorov d, << 4 which avoids the hydrodynamic i wakes of particles. The external fo cle then reduces to the drag force. advanced according to the equatio dx: dup,4(t) 3 p CD |ufep Up di 4 p, d' where up,4 is the velocity of the pa tion of the center of the particle, p particle. CD is the drag coefficien can be written as: C'D = 2 [1 + 0.15Re0.687 Rep v, is the local relative velocity between the particle and the surrounding fluid written as vr = u, ufep. ufop is the locally undisturbed fluid velocity by the particle in question. This velocity is obtained by interpolating the fluid velocities at the grid nodes, where the fluid ve- locities are stored, at the particle position, using third order Lagrangian interpolation scheme which is precise enough to accurately calculate the fluid velocities. Handling of two-way coupling. The back effect of the particles on the fluid, the term fe, in Navier-Stokes equations, is taken into account using the Point Source In Cell approach developed by Crowe et al. (1977). Point Source approach accepts particles which are very smaller than the Kolmogorov scales and it depends on the multipolar formulation of the Stokes' equations for a rigid sphere subjected to a turbulent flow. Each pole Reference simulation and parameterization of two- Way coupled simulations. The simulations performed in this study consider the same initial fluid turbulence field. The statistics of the reference field is tabulated in Table 1. Two-way coupled simulations are character- ized by two dimensional numbers; mass-loading and the Stokes number St which are defined as: pJ Tf where up is the volumetric loading of particles and 7, is the particle relaxation time. Tf is the Lagrangian timescale of the fluid elements. They are given by: N,nd 6L pp 4 dp 1 p 3 CD IUp Ufpg} 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 Table 2: Parametrization of simulations. Values inside the boxes show the number of particles NI, (all numbers are non-dimensional). -T, = 1.5 y, = 3.O Ty, = 6.O Ty, =12.O 0.16 1 x 1283 0.5 x 1283 0.25 x 1283 0.125 x 1283 0.32 2 x 1283 1 x 1283 0.5 x 1283 0.25 x 1283 0.65 4 x 1283 2 x 1283 1 x 1283 0.5 x 1283 1.32 8 x1283 4 x1283 2 x1283 1 x1283 Table 1: Statistics of the reference monophase simula- tion (all numbers are non-dimensional). Variable Symbol Value Characteristic velocity a 0.088 Fluid kinetic energy q~ 0.0118 Dissipation 7.7E-4 Turbulent Reynolds Number Re L 96 Taylor Reynolds Number Rex 48 Length of the box Lb 2i Longitudinal large scale Ly /Lb 0.0864 Transversal large scale Ly /L, 1.9797 Taylor length scale A,/lLb 0.0438 Kolmogorov length scale ty/Lb 0.0032 Maximum wavenumber ky,,,,. 1 1.2608 Eulerian integral timescale / eddy turnover time TE/lT, 1.02 Lagrangian integral timescale Tr//TE 0.8275 Kolmogorov timescale r,,/Te 0.131 Table 3: Particle physical properties (all numbers are non-dimensional). 7,, 1.5 3.0 6.0 12.0 p> 2000 4000 8000 16000 cl 0.00266 0.00266 0.00266 0.00266 troduce it from the corresponding side of the domain. In this way, particles have an infinite space of free motion, Two-way coupling is turned on from the initial condi- tions and particles are time-stepped for 4 or 5 relaxation time so that all the statistics concerning the fluid and the particle phases become stationary in time. All the statis- tics, reported at the results and discussion section, are calculated after this time for at least 10 eddy turnover times to obtain robustness. Additional to the solid particles used in the simula- tions, a population of fluid elements is also introduced into the reference flow field to calculate the Lagrangian statistics of the fluid in the stationary level after the tur- ~$0.4 -0.2 0 2 4 6 8 Tf/71 Figure 1: Ghost particle test. qj, is the covariance of one-way coupled (ghost) particles, qp is the covariance of physical particles. T+ is the non-dimensional time of the simulation, It is obligatory to observe in the DNS simulations the dy- namic evolution of the system for a fixed 9 changing 7ia and vice versa. However, the Lagrangian timescale af- ter the coupling is turned on is not known a priori and it is difficult to obtain the same Stokes number for a given particle relaxation time. For simulations conducted here, particle relaxation time is constant, it does not change whether there is two-way coupling or not. Therefore, the reasoning of the simulations is based on the mass- loading and the particle relaxation time. The simulation parameters are presented in Table 2. Particle parame- ters to impose different particle relaxation times are pre- sented in Table 3. Performing simulations. For each simulation, NI,par- ticles are released into the reference turbulence field with a spatially homogeneous distribution. Initially, particle velocities are put equal to the fluid velocity at parti- cle positions. Periodic boundary conditions ensure the homogeneous distribution of particles during their dy- namic motion. These boundary conditions take a parti- cle exiting domain from a boundary of the cube and in- bulence is modulated by solid particles. Statistical approach Ensemble averages are used to calculate the statistical quantities in this study. Ensemble averaging operator considers the arithmetic average calculation over infinite number of realizations of the phenomenon in question. Applied to gas-solid flows, we can define the statistical averaging operator as: where Hf&, is the number of fluid-particle flow real- izations. Using this averaging we can define mean and fluctuating velocities of both phases as: Uf,i = (uf,i) a7,i = uf,i Uf,i (13) Up,, = (Up,i) Up,i = Up,i Up,i (14) We can also quantify the statistics calculated at the par- ticle positions using the simplified writing (), which is related to the ensemble averaging operator by (-) = up (-)p. n, here is the particle density number in a unit volume. As will be seen in the course of this paper, this statistics concern the properties of the fluid seen by the particles . Lagrangian stochastic modeling of gas-solid flows Stochastic modeling turbulent flows began with the fa- mous paper of Taylor (1921) and continue to receive much attention from the researchers from different do- mains. The application is simple. A turbulent flow is represented by a number of fluid particles which are time advanced according to the stochastic trajectory equa- tions (Pope 1994). In gas-solid flows, Lagrangian stochastic modeling is used to provide the fluid statistics encountered by the particles during their trajectories (Simonin et al. 1993). This approach not only allows the writing of the trans- port equations for the turbulent drift velocity and the fluid-particle correlations, but also it provides closure to the Boltzmann type joint probability density function transport equation (Simonin 2000). Langevin equation for fluid velocity along fluid el- ement trajectories. According to Haworth and Pope (1986), the increase in the fluid velocity of a fluid ele- ment can be modeled as a stochastic process. Applica- tion to turbulence comes up as decomposing the velocity 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 and the pressure in Navier-Stokes equations into mean and fluctuating parts: 1 BP du,, (t + bt) = + v VUy, d + f, di (15) and then modeling the fluctuating part of the equation with the stochastic Langevin equation as: 1 BP ,iPf d8 i 2 f~'i dL" +Afgi (u; (t) Uf,j dt + Bf .'TU -II, di (16) where the terms containing the tensors Af, y and Bf,ij are the drift and diffusion terms, respectively. 6W, is the isotropic Wiener process with zero mean and variance dt. The last term is the two-way coupling term modeling of which closes the Langevin equation completely. The two-way coupling term in the Navier-Stokes equation is known in the context of point sources (see the section 'Handling of two-way coupling' above), however, the corresponding term in Langevin equation is not known a priori because one-to-one correspondence between the drift and diffusion terms of the Langevin equation and the fluctuating part of the Navier-Stokes equation can not be made. Langevin equation is qualitatively incorrect for in- finitesimal time separations, it is consistent with the in- ertial zone where the timestep is in the range 7, << di << Tf. The diffusion coefficient is derived in this context and usually it is justified by the Kolmogorov theory for the turbulent structures of the inertial zone. However, we are going to stay general enough and using the isotropy, the writing will be simplified as: Af7ij = Af64, Bf,ij = By da In this paper, the purpose is to model the two-way coupling term in order to obtain the diffusion and drift coefficients. Closed Langevin equation for fluid el- ements then should cover the following macroscopic properties of fluid turbulence: Same Tf as the one measured from DNS of homo- geneous isotropic turbulence Same mean fluid velocity Uf,i transport equation Same q~ equation as the one derived from the Navier-Stokes equations (-) = lim 1 E (.) Hyg, oo LH/&P Hyg 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 where the turbulent transport term is written as: This methodology includes following steps consistent with the work of Pope (2002): To determine Af using the Lagrangian autocorrela- tion function To determine Bf in terms of Af using the second order stress tensor transport equation Fluid autocorrelation function. For isotropic turbu- lence, autocorrelation function is defined as: R(i(t) = (u;,4(to)u;,4(to +t)) (19) where statistical operator is defined in (12). Differen- tial equation governing the Lagrangian autocorrelations is derived from (16) as: Df,i x j,9 a, and production term is written as: Pf ,is = / of ,m U,,y i \ 8Uys a ofmi 8xm %f,ij is the pressure deformation term which will not be written explicitly here. Comparing the Reynolds stress equation above to the one derived from the Navier- Stokes equation gives: 7f,ij tf,ij + nRs,i + Has = +B 6 4 + SSII (28) where #7,ij is the fluctuating pressure-velocity correla- tion tensor, e7,ij is the dissipation tensor, IF~g is derived from the forcing term in (1). For decaying homogeneous isotropic turbulence, we can simplify the relation. Using the isotropy, the pressure-velocity correlation term can be taken as zero, /f,ij = 0 and we do not have the term IFgy. Once Af is known using the autocorrelation function, Bf can be obtained from (28) in terms of Af and the two-way cou- pling terms as: 3BZf = -2Aiq- 2ef + I,,d II (29) where the contraction of indices i and j is used. For the forced turbulence, contracting the indices of (28) results in: where q~ is the fluid kinetic energy as defined in 3. This relation forms the 3rd condition to be verified by the Langevin equation for the fluid elements. Langevin equation for fluid velocity along solid particle trajectories dRf (t) di = AfRf(t) u},4~i(to)Inul(to +t)) Lagrangian timescale can be defined as: T/f = T R (t)di (21) SR((0) Jo Fluid mean momentum equation. Volumetric loading of particles is negligible in this study, ap << 1. This leads to the mean momentum equation derived from (16) as: 8~pUf ~ B'U + pUf,y 8 8xy BP -- + p V2 Uf,i4 8xi +De (II,i) (22) where the turbulent transport term is written as: De = p-8 a(23) where the symbol is omitted in the fluid velocities be- cause the high order moments from the Langevin equa- tion are assumed equal to the statistics obtained from Navier-Stokes equations. The necessary condition for the Langevin equation to represent the mean motion of the fluid is written as: (nu, )=(fi) Fluid Reynolds stress equation. Reynolds stress equation derived from (16) is written as: In presence of inertial particles, the trajectories of the fluid elements and solid particles are not the same. As the calculation of the drag force acting on a particle is based on the information of the fluid velocity at the par- ticle's position, Simonin et al. (1993) proposes using a Langevin type equation to model the fluid velocity en- (25) countered by a particle during its trajectory where the a a + U 7au 3 D y,ij + Pf,ij + 7f, +Alb,64 (u;,ju;~m + A764ml *f;,iu;,m ) +B 64+ I 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 Fluid Reynolds stress seen by the particles equa- tion. The methodology using the Langevin equation for the fluid velocity seen by the particles allows the writing of Reynolds stress seen by the particles equation written as: deviation between the trajectory of the particle and a fluid element, which are assumed to be at the same initial position, are accounted by an additional term. We use the same equation as proposed by Simonin et al. (1993) to calculate the fluid velocity at the par- ticle position, however, as this velocity is modified by the surrounding particles in case of two-way coupling mechanism, we also add an additional term to take into account this effect. The equation is written as: '"~('"';[ f ~z1 BP du}Op~ / 2 ,i s +(. ; -. ;) t (31) where the last term accounts for the deviation of the particle trajectories from the fluid element trajectories. There are different possibilities for this term (Minier and Peirano 2001). The form written above is proposed by Simonin et al. (1993) and it takes into account the correct behaviour of the fluid-particle covariance. Therefore it will be used in this study. Using the isotropy, the writing of the drift and diffusion coefficients will be simplified as: Afep,ij = AfepGif (32) Bfep,ij = fepGsy (33) It is to be noted that this equation is not an acceler- ation of a fluid element, it is simply a time derivative of the fluid velocity computed along the trajectory of a solid particle. Fluid autocorrelation function seen by the particles. The differential equation governing the fluid autocorre- lation function viewed by the particles can be written as: ddtp = Afep ~ept f O,i 0 us 0 (t+ t)) (34) The integration of this autocorrelation function gives the fluid Lagrangian timescale viewed by the particles as: T Op =R e (0) Opt~ (35) This time scale is the most critical for the two-way cou- pling studies because it sees the highest modification due to the particles, as will be seen in results section, The definition of the Stokes number will then be mod- ified as: St (36) T Op d(UfOp~i f Op,@ '"+ Up,m D fep,ij Pfep,ij +nAf~pim, ( i~il, fpm +B Op +nRfos~, (37) where the turbulent transport term is written as: ftpd s3 ftp,i" .' i u Df dxmi = 7 and production term is written as: I'~"=~;i,17; p7i BU Pfpi f~ ftp. Contracting the indices for the homogeneous isotropic stationary turbulence, it is obtained that: 2Afep9 op op op 0 (40) where q Op iS the fluid kinetic energy seen by the parti- ClCS defined as: 9 :Op f O(; p,i f Op~ip It is worth noting that the transport equation (37) for the Reynolds stresses seen by the particles is not nec- essarily the same as the one derived from the Langevin equation for the fluid element trajectories due to the av- eraging operator weighted by the particle number den- sity up in the case of fluid velocities along the particle trajectories. Fluid-particle covariance transport equation. Trans- port equation for the fluid-particle covariance tensor can be derived using the Langevin equation for fluid velocity 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 Then we can think of a mean drag contribution for the two-way coupling term in the Langevin equation and leaving the fluctuating part of the drag force to the drift and diffusion terms. Thus we can formulate the two-way coupling term as: along the particle trajectories. It can be written as: u2p + npUp,m = Dfp,ij + Pfp, +2 f,; p F, +Ipiad nyUfp,. i i +np~~l ./ ;IIy (42) The terms on right hand side are, respectively: Turbulent dispersion of the covariance by velocity fluctuations written as: Dfp,ij = 8m fpi, 4) - Production terms by the mean particle and fluid veloc- ity gradients, written as: FI~s=-np i f: Op,i pi~m -n, ;upm Va(44) Two-way coupling term takes into account the inter- phase turbulent momentum transfer, such as dragging of the particles along the turbulent eddies Last two terms are derived from the drift and two- way coupling terms of the Langevin equation and takes into account the pressure-deformation, viscous dissipa- tion and the crossing trajectories effect (Boivin 1996) By contracting the indices of the tensor for the isotropic turbulence, we can define the fluid-particle co- vaniance as: IL, = '(F,,4) pp u2pm' Up y~ 44 PfTp Results and discussion Turbulent particle dispersion. The modeling steps mentioned in section Lagrangian stochastic modeling are to determine the drift and diffusion coefficients. Model is tested against the DNS simulation results according to the particle dispersion theory of Tehen (1947)-Hinze (1975) where the particle agitation is de- fined in terms of the agitation of the fluid. Hinze (1975) obtained, using spectral analysis, the results of Tehen (1947) and showed that the agitation of the particles is in equilibrium with the agitation of the fluid after suf- ficiently long time. According to the theory of Tehen- Hinze, particle dispersion is controlled by the inertia of the particle when there is no relative motion between the phases. Deutsch and Simonin (1991) showed that for certain Stokes' numbers, the particle dispersion coeffi- cient D~ is higher than the fluid element dispersion coef- ficient D) and this increase is related to the Lagrangian timescale seen by the particles T/Oep. This timescale shows the interaction time of particles with the largest turbulent eddies and according to Deutsch and Simonin (1991), this increase in the dispersion is induced by en- hanced correlation of the particles with eddies of largest scale. Thus they derive the particle dispersion coefficient in terms of fluid statistics seen by the particles as: D 2" D = q gT Op (49) Assuming an exponential form for the Lagrangian timescale, they derive the relation for the extended the- ory of Tehen-Hinze as: T/Op 4f p = 2q OF f (50) L7P Developing the differential equations governing the fluid autocorrelation functions seen by the fluid elements and by the solid particles given by (20) and (34), using the mean drag model given by (48), the coefficients Af and Af Op iS obtained as: A, = A fep p (51) Deutsch and Simonin (1991) showed that there is a negligible bias between the Lagrangian timescale seen '/v = (1 f Op;i p~i p Modeling of two-way coupling term If we follow the reasoning of Haworth and Pope (1986), two-way coupling term in the Navier-Stokes equation can also be decomposed into mean and fluctuating parts as: fui = ( fui)+ fli (47) 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 by the fluid elements and the solid particles. Then we can formulate a first 1 1 ghs'l'is Tfe = Tf (52) which leads to the writing: is proportional to the Eulerian characteristic timescale by a constant. Using (30) and (40) written for homogeneous isotropic stationary turbulence, coefficients Bf and By up can be written as: Bf= Bfyp= dfort op, (55) 4;op =A4f In turbulence modeling context, Lagrangian timescale can, be assumed proportional to a characteristic Eu- lerian timescale of turbulence which is usually given in terms of the fluid kinetic energy q~ and dissipation rate t ratio as: Fluid-particle covariance tensor equation (42) can be simplified using homogeneity and isotropy along with stationarity which leads to the writing of: qy,- = 29ep ,, (56 where using the A4; o given by (51), we obtain the re- lation for the extended theory of Tehen-Hinze given by (50). It is to be noted that this relation is the same as the relation in one-way coupled flows which brings us to the conclusion that with mean drag model, the two- way coupling has no direct effect on the equilibrium of Tehen-Hinze. Deutsch and Simonin (1991), Fevrier (2000) showed that the difference between the fluid kinetic energy seen by the fluid elements and the solid particles is negligible which brings us to the second Il)1s'lllc'\i\ q,4,, = q, (57) Two-way coupling terms in the second order stress tensor transport equations (25) and (37) and the fluid- particle covariance transport equation (42) is zero with mean drag modeling. This modeling dictates that the two-way coupling has no direct effect on these statistics, thus we obtain the same set of equations as for the one- way coupled flows. Tehen-Hinze relation (56) is tested against DNS ex- periments and the results are shown in figure 3. As seen, the evolution of the numerical results as function of the particle inertia follows the theoretical line for the high inertia particles (the left side of the graph, small It is remarked that the increasing mass loading re- duces the particles inertia and therefore measure points move towards the low inertia part of the graph (right hand side). In fact, in the study conducted here, par- ticles can not produce or enhance turbulence, they can only attenuate. Attenuated turbulence has higher inte- gral timescales which reduces the inertia (Stokes num- ber) of the particles (see the definition of the Stokes' number). Increasing mass loading also corresponds to the in- crease in the fluid-particle covariance. G.In~islc'llll with the reduction in particle Stokes number, particles are more and more controlled by the turbulence dynamics. TL =C where ('7 is a constant. This relation is accounted ac- curately by the drift and diffusion terms of the Langevin equation in homogeneous isotropic turbulent monophase flows (Pope 1994). To test the behaviour of the constant (', in two-way coupled turbulent flows, the DNS measures of the La- grangian timescales and the fluid kinetic energy, dissi- pation rate ratios are plotted in figure 2. As seen on the 0. 'T 0.4 0.2 Oa oao 100 101 T/ /4 7 Figure 2: Ratio of the Lagrangian timescale to the Eu- lerian characteristic timescale of turbulence as function of the particle inertia; 0:p = 0.16, o: = 0.32, n: = 0.65, 0:p = 1.32. figure, the ratio of q /t to the Lagrangian timescale T/ depends on 9 and the inertia of the particles. For the high mass-loading simulations, it varies sensibly with the modifications in the particle inertia. This variation of the Lagrangian timescale should be properly taken into account in the Langevin equations proposed which is difficult and requires further work. A priori, we ignore this variation and assume that the Lagrangian timescale 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 The deviation observed for small inertia particles (right hand side of the graph) indicates an underestima- tion of the fluid-particle covariance and it is in fact due to the assumption of exponential form for the autocorre- lations viewed by the particles. Indeed, due to the low Reynolds number of 96 in the study conducted here, the autocorrelation functions deviate from the exponential form for small time increments (Boivin 1996). The low Reynolds number effects can be taken into account using the model proposed by Sawford (1991) for the correla- tion curves. This will not be presented in this study. 0.8 N9 0.6 S0.4 0. 10 100 101 102 Figure 4: Classical theory of Tehen-Hinze. The line and the symbols represent the same condi- tions as in figure 3 Effect of two-way coupling on the fluid statistics seen by the particles. The results presented in the pre- vious section put in question the validity of the hypothe- ses made (52) and (57). We performed several one-way coupled simulations to compare our results with the re- sults of Deutsch and Simonin (1991). Two-way coupled simulations are also compared. As seen in figure 5, the fluid kinetic energy seen by the particles does not change with inertia of the particles and it is sensibly equal to the kinetic energy seen by the fluid elements for one-way coupled simulations. The results are in coherence with the results of Deutsch and Simonin (1991). Two-way coupled simulations, on the other hand, have the fluid statistics viewed by the particles signifi- cantly different than the ones viewed by fluid elements. This figure suggests to look also the fluid Lagrangian timescale seen by the particles because these two quan- tities determine the particle dispersion, see (49). Evolution of the fluid Lagrangian timescale viewed by particles with inertia is shown in figure 6. One-way coupled simulations are also plotted in the same graph with comparison to the numerical results of Deutsch and Simonin (1991). For very low inertia particles (the right hand side of the graph), it can be noted that in one-way coupled flows, the Lagrangian timescale seen by the par- ticles and by the fluid elements is fairly equal indicating the the particles behave like fluid elements (see also the figure 5). For, two-way coupled flows, we do not have any simulation in the very low inertia limit due to the computing source restrictions. Indeed, for decreasing in- ertia, we need larger number of particles in order to ob- tain the mass-loadings considered in this paper (see the tables 2 and 3). In any case, the tendency of the DNS 10 100o Figure 3: Extended theory of Tehen-Hinze using the fluid characteristics seen by the particles. Symbols are DNS results and represent the same conditions as in the figure 2. -: Model given in (56) obtained using mean drag force given in (48). From the other part, this deviation observed indicates that the fluid statistics seen by the fluid elements and the solid particles are sensibly different for small Stokes numbers. This in turn puts in question the by plkses c' c made in the development of the model. Thus the same graph is plotted using the fluid statistics viewed by fluid elements, e.g., replacing the q ,, by q) and T/Oep by T . In contrast to the fluid statistics seen, the true fluid quantities shows that the Tehen-Hinze (56) have ten- dency to overestimate the fluid statistics for increasing mass-loadings. This behavior of the experimental mea- sures ensures that, as noted above, the statistics are dif- ferent for fluid elements and solid particles. We can conclude that the fluid statistics seen produces good dispersion results for the theoretical line of Tehen- Hinze which justifies the use of the fluid statistics seen in modeling the particle dispersion for two-way coupled gas-solid flows. 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 B-* * results for two-way coupled flows shows that decreas- ing inertia makes particle behave like fluid elements. In one-way coupled simulations, it can be concluded that in coherence with the results of Deutsch and Simonin (1991), particle dispersion is controlled by the changes in Tf "I with varying inertia. Our simulations show that in two-way coupled flows, the dispersion can be controlled by the variations in both fluid kinetic energy viewed and the Lagrangian timescale viewed by the particles. As suggested by Squires and Eaton (1991) and Deutsch and Simonin (1991), in one-way coupled flows, the augmentation in the Lagrangian timescale seen by the particles corre- sponds to an improved correlation of the particles with the large eddies and this phenomenon is related to the preferential concentration of the particles into special re- gions in the flow which is also verified in the simulations of Fevrier (2000). We remark more pronounced increase in Tf "I in two-way coupled flows which can be related to the same phenomenon. The changes in the fluid ki- netic energy seen is also \ignilk~.llll and there is contin- uous exchange of energy between the phases. However, we do not have a good explanation for these changes, yet. More study is required for the preferential concen- tration mechanism in two-way coupled flows. -1 I 0.8 101 100 101 T f/7p Figure 6: Effect of particle inertia on the fluid La- grangian timescale seen by the particles. Blank symbols represent the same conditions as in figure 2. *: Numerical results of Deutsch and Simonin (1991), *: Results of one-way coupled DNS simulations Conclusions The statistics of solid small particles suspended in a tur- bulent flow were investigated in presence of two-way coupling. The modulation of turbulence by a particle cloud is a difficult phenomenon because the interactions occur in particle positions which is difficult to take into account in Eulerian models. From this point of view, Lagrangian stochastic models provide powerful tools to simulate the fluid element trajectories and the fluid ve- locities encountered by particles along their trajectories. To the Langevin equation, we added an additional term to take into account the effect of the particles on the undisturbed flow. Modeling of this term with mean drag force produces results in agreement with DNS sim- ulations' results in terms of particle dispersion and ad- ... .. .... vantageous due to the simplifications in transport equa- lo2 103 tions of second order. However, the by~l polkssc~ are very open to be questioned and the mechanism of preferential concentration should be investigated in more detail. +* \ a- ; 10 100 10 T/f/7 Figure 5: Effect of panticle inertia on the fluid kinetic energy seen by the particles for one-way cou- pled and two-way coupled flows. Blank sym- bols represent the same conditions as in fig- ure 2, *: Numerical results of Deutsch and Si- monin (1991), *: Results of one-way coupled DNS simulations References Boivin, M., Etude de l'influence des particles sur la turbulence B partir de simulations directed et de simu- lations des grandes 6chelles d'6coulements diphasiques gaz-solides homogenes isotropes stationnaires, These de l'Universit6 de Rouen, Rouen, France, 1996 Boivin, M., Simonin, O. and Squires, K.D., Direct nu- merical simulation of turbulence modulation by particles 7th International Conference on Multiphase Flow, ICMF 2010, Tampa, FL, May 30 June 4, 2010 Simonin, O., Deutsch, E. and Minier, J.P., Eulerian pre- diction of the fluid/particle correlated motion in turbu- lent two-phase flows, Applied Scientific Research 51, 275-283, 1993 Simonin, O. and Squires, K.D., On two-way coupling in gas-solid turbulent flows, in Proceedings of FEDSMO3, 2003 Squires, K.D. and Eaton, J.K., Particle response and tur- bulence modification in isotropic turbulence, Phys. Flu- ids 2, 1191-1203, 1990 Squires, K.D. and Eaton, J.K., Measurements of par- ticle dispersion from direct numerical simulations of isotropic turbulence, J. Fluid Mech., 226, 1-35, 1991 Taylor, G.I., Diffusion by continuous movements, Proc. London Math. Soc., 20, 196-211, 1921 Then, C.M., Mean value and correlation problems con- nected with the motion of small particles suspended in a turbulent fluid, PhD thesis, University of Delft, The hague, 1947 Vermorel, O., Bedat, B., Simonin, O., Poinsot, T., Nu- merical study and modeling of turbulence modulation in a particle laden slab flow, Journal of Turbulence, Vol. 4, 2003 in isotropic turbulence, J. Fluid Mech., 375, 235-263, 1998 Crowe, C.T., Sharma, M.P., Stock, D.E., The particle source in cell (psi-cell) model for gas-droplet flows, J. of Fluids Eng., 325-332, 1977 Deutsch, E. and Simonin, O., Large eddy simulation ap- plied to the motion of particles in stationary homoge- neous fluid turbulence, ASME-FED, Vol. 110, 35-42, 1992 Elgobashi, S.E. and Truesdell, G.C., On the two-way interaction between homogeneous turbulence and dis- persed solid particles: I. turbulence modification, Phys. Fluids, A 5, 1993 Eswaran, V. and Pope, S.B., An examination of forcing in direct numerical simulations of turbulence, Comput- ers and Fluids, 16(3), 257-278, 1988 Fevrier, P., Etude num~rique des effects de concentration pref~rentielle et de correlation spatiale entire vitesses de particles solides en turbulence homogenes isotrope sta- tionnaire, PhD thesis, INP Toulouse, 2000 Haworth, D.C. and Pope, S.B., A generalized Langevin model for turbulent flows, Phys. Fluids, 29(2), 387-405, 1986 Hinze, J.O., Turbulence, New York, McGraw-Hill, 1975 Koch, D., Kinetic theory for a monodisperse gas-solid suspension, Phys. Fluids, 2 (10), 1711-1723, 1990 Lele, S., Compact finite difference schemes with spectral-like resolution, J. Comput. Phys., 103, 16-42, 1992 Minier, J.P. and Peirano, E., The pdf approach to tur- bulent polydispersed two-phase flows, Physics Reports 352(1-3), 1-214, 2001 Pope, S.B., Lagrangian pdf methods for turbulent flows, Annu. Rev. Fluid Mech. 26, 23-63, 1994 Pope, S.B., Stochastic Lagrangian models of velocity in homogeneous turbulent shear flow, Phys. Fluids 14(5), 1696-1702, 2002 Sawford, B.L., Reynolds number effects in Lagrangian stochastic models of turbulent dispersion, Phys. Fluids A 3(6), 1577-1588, 1991 Simonin, O., Statistical and continuum modelling of turbulent reactive particulate flows. Part I: Theoretical derivation of dispersed phase modelling from probabil- ity density function kinetic equation, VKI for Fluid Dy- namics, Lecture Series, 2000 Contact Us | Permissions | Preferences | Technical Aspects | Statistics | Internal | Privacy Policy © 2004 - 2010 University of Florida George A. Smathers Libraries.All rights reserved. Acceptable Use, Copyright, and Disclaimer Statement Last updated October 10, 2010 - Version 2.9.7 - mvs


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Osmond Brookes Commercial Property Consultancy
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My name's Lona Hanzel. I'm a cardiac physiologist.
I'll always say I'm a cardiac physiologist, it's one of those professions that not a lot of people know what it is. The patient or whoever will always go "Thank you, nurse or thank you, doctor," which, you know, I suppose it depends how clean I'm looking that day. You know what I mean - how disheveled I look. I work here at the Heath Hospital in Cardiff. I've literally done my growing up here, you know, from being a teenager, twenties, thirties, now I'm in my forties. I haven't worked anywhere else. So it's quite funny. It's like some of the students, I could be their mother you know, and I've got to keep on stopping myself sometimes "When I started...," you know, or "Back in my day...," or "What we used to do".
Like most people of my age we kind of fell into it. I didn't know what a cardiac physiologist was when I started the job. I mean, in those days we were called physiological measurement technicians. Now the PMT nurse isn't the best kind of title to have, so that's why that's changed. The majority of what I do, most of the time is, I do ultrasound scans, so that's where we look at people's hearts and we look at the structure of the heart to see the way the heart valves are working, your heart muscles working, directing the blood flow within the heart, so that can tell us a lot of information. So that's my aortic valve that you're hearing. It's not going too fast is it, that's not too bad.
So, sometimes what can happen is, I'd have dealt with something not quite nice in one room. Well, this morning, I'd been from a cardiac arrest and then I'm dealing with Mr. Whoever, who's complaining he's been waiting ten minutes. "Oh well, I've been waiting here one hour already for my test," and I'll go "Oh, but your appointment is in ten minutes' time," and they're like "Oh, well, yes, I had to get a lift, so I was here an hour early." And you're like "Oh, I'm trying my best, you know." Can't please everybody. It's, I mean, like I used to work in waitressing years ago. It's the same kind of skills. You're not going to please everybody. But you hope to. I think I'm up to about ninety nine percent maybe, you know. And I'm getting a lot, these days, of people like "You see this NHS, it's really good, I don't know what they're on about, I'd better write to the paper and just let them know." So you get a lot of that at the moment, because the NHS is going through like a negative press. I've got patients that are trying to look after me. It's kind of sweet, you know what I mean.
I couldn't imagine doing a regular nine to five. I've got a sister a year younger than me. She works in HR for a huge company. And it's quite funny, having that discussion about private and public sector. You know, like my sister, she just had a massive bonus and I'm going "Yeah, no we don't get that – yeah, in fact I didn't even get my lunch today. Yeah, and hang on, you were complaining about my pension because..?" you know, and even though her pension will be much better than mine, but we've got the similar kind of qualifications and everything, but, I mean I really enjoy what I do. And I get a good sense from what I do and I'm happy with what I do, I can't imagine doing something I wouldn't be happy doing.
Obviously, I am going to win the lottery one day, you know what I mean, you got to be in it, I buy my ticket. Maybe once a month or so, then would I come back to work if I won the lottery? I kind of think, yes, I would, but then I kind of think I'd be using up somebody's opportunities, well, because it is a fab job. I find it a fab job. I come in here early. I start half seven. I'll finish at three. So then my job is then to look after my daughter. I'll, say, leave here in a rush because you can't finish it on the dot. I mean that doesn't happen, but luckily my daughter's school's just around the corner for me to pick her up. So there's been many occasions where I've left here running to pick my daughter up from school, where she'll be looking at me quite cross and then that cost me like ten pounds and getting her like a magazine and stuff just to appease her, just saying sorry, sorry, sorry. In the early days, when I didn't have a family, you kind of take things for granted. It didn't bother me doing paediatrics in the path lab because it's just get onto the job, but I didn't really have that connection like "Yes, the parents are upset. They're going to be upset." Whereas now, sometimes I'll find, like, I might shed a tear because I'll be thinking of my own family as well.
So it's quite interesting, because you never know how your day's going to go. So a good day for me is knowing I've helped people. I do like being thanked, that's bad, I know. I do like it when people say thank you. At the end of the day, or that people are just leaving with a smile and that for me is a good day, and sometimes you will have outcomes that have been upsetting to you, you just know that you've done the best you can and then you just move on from that and try and give the next person that you're seeing, or you're dealing with, all your time and attention.
There was a time when I wouldn't have to worry about getting a pen. Now it's like "Yeah, no, sorry we've got no pens, we've got no stationery, we've got nothing." And I used to get half an hour when it came to doing an echo. With some patients, it's quite difficult to get them into the room - They've got time to undress, as you can imagine, in winter time there's a lot of layers. But now it's shortened down to twenty minutes. So this does seem to be a lot more pressure, and it does seem to be more about figures than it does about the patient, which it should be, you know, because some patients, I'll be able to scan quick, easy, no problems, but then I'd like a little bit more time, little bit more flexibility, with some patients and not feel guilty about it, but we're constantly being reminded of our referral to treatment times on our waiting lists. So it's something that the management and the directors are always, not putting pressure on, but making us aware of these targets. Sometimes it seems like it's a constant stream and never-ending kind of conveyor belt, sometimes it seems like it's trying to get, as well, with the patients, that they don't feel like that part of this conveyor belt. I try to treat everybody as if you're like my family member and obviously I want to do the best for you. And that's where, sometimes, I can be too chatty as well. So, sometimes, I kind of had to try and see if the patient wants to chat or not. So it's a matter of gauging it just right, as well, with people. I think I do that alright. But, yeah, I haven't been told to shut up yet!
I went to Africa to scan children. I'd saved up, I was lucky enough and I took time out on my own annual leave, it was something I felt was important to do. It was hard for my family of course, I was away for a week, but then we had Tango and Skype and Whatsapp, so it wasn't too bad either. You know, like my husband could Skype in and go "Where have you put Molly's roller skates?" and it's like "Yeah, if you look in this cupboard." It was quite heartbreaking to kind of go. Because you feel like you've done a good job, but it was nice to be home as well, it's kind of appreciate and appreciate our NHS as well. It's not the same job day in, day out. You're always meeting new people and people are amazing. There's a lady who sticks in the mind, who's in the nineties, and she's on the fourth marriage, and then you will meet others that, you know, are young and they're doing so many fantastic things - that's what keeps you motivated and quite excited about the job.


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The Syrian armed opposition's al-Tawhid Brigade has its own medical and media units as well as its own Sharia court.
The rapid developments in Aleppo and its countryside point to an impending confrontation between the Islamic State in Iraq and al-Sham (ISIS) and the al-Tawhid Brigade, which is considered one of the biggest fighting factions in Aleppo and its countryside.
Special sources provided As-Safir with highly credible information that the al-Tawhid Brigade's military commander, Abdul Qadir al-Saleh, is on a secret visit to the United States. The visit started about a week ago.
Saleh recently praised Jabhat al-Nusra and "the high coordination between them and the rest of the factions fighting on the ground. … [There is] great coordination with them on the military side."
That was not the first time he made such a statement. In April, he expressed his "complete rejection to include Jabhat al-Nusra on the US terrorism list," adding that the group didn't engage in terrorism.
His remarks are not surprising considering the relationship between Tawhid and Jabhat al-Nusra. Information from the field confirms that Saleh was one of the architects of adding Jabhat al-Nusra to the list of factions that signed the so-called Declaration #1, in which the factions announced "the revocation of revolutionary legitimacy from the oppositionist Syrian National Coalition." Also, Tawhid and Jabhat al-Nusra were established at about the same time. Some Jabhat al-Nusra fighters participated in the Radio Battle under the Tawhid banner.
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So what is story of the al-Tawhid Brigade?
Tawhid's formation, and its entry to Aleppo
The al-Tawhid Brigade was founded on July 18, 2012, through the merger of a number of armed groups in the countryside north of Aleppo, which is adjacent to the Turkish border. Tawhid later joined the "Revolutionary Military Council in Aleppo and its countryside," which is led by Col. Abdul Jabbar al-Aqidi. It was a purely organizational council and didn't have its own forces on the ground. Tawhid also played a key role in forming the Aleppo Sharia Council in an alliance with Jabhat al-Nusra and the Ahrar al-Sham Movement. But Jabhat al-Nusra later withdrew from that council.
Tawhid's formation is mainly linked with a decision to make opposition gunmen enter Aleppo. Accurate accounts confirm that the decision was at the behest of Turkey directly. According to the accounts, Turkish intelligence coordinated with the head of the Military Security branch (then Mohammed Mefleh) to facilitate the entry of the gunmen to Aleppo and that Tawhid be the first organized armed faction to enter the city via the so-called al-Furqan battle on July 20, 2012.
Sources from Tawhid told As-Safir that the group entered Aleppo according to the following account:
"Fighting groups gathered in the north [Aleppo] countryside of Mareh, Andan, Tal Rifaat, and others. They were joined by the Nur al-Din al-Zanki Brigade from the west countryside. Then fighters of special moral and combat quality were selected and entered [Aleppo] in successive batches of 200 fighters each through Bab al-Qadim and settled in al-Ard al-Hamra, in a school on the junction of al-Sheikh Najjar al-Qadim. Meanwhile, the Nur al-Din al-Zanki Brigade entered the Salahuddin neighborhood under the Tawhid banner."
According to the source, the "regime faced this move by moving a column of tanks on the Hanano–al-Indharat Housing highway. And then the clashes began. Three tanks were destroyed and one was captured."
Tawhid gunmen fanned out toward Bab al-Nairab, where they clashed with the Berri clan, which is loyal to the regime. They captured, tortured, and killed Zaino Berri, accusing him of "leading the Shabiha [regime thugs] of that group." In August 2012, Amnesty International condemned the incident, saying that it "represented a serious violation of international humanitarian law and is a war crime."
Jabhat al-Nusra gunmen join the fight on the side of the al-Tawhid Brigade
The Nur al-Din al-Zanki Brigade entered the Salahuddin neighborhood under the Tawhid banner. Jabhat al-Nusra had formed in secret and its gunmen fought the Radio Battle under the Tawhid banner. Most Jabhat al-Nusra fighters had been released from Saidnaya prison under the June 2011 general amnesty.
The gunmen seized many Aleppo neighborhoods in a relatively short period to time. Tawhid declared the neighborhoods extending from Salahuddin to Sakhour as "neighborhoods that were liberated in battles in which 20 Tawhid martyrs had fallen," according to sources from within Tawhid.
Then the Syrian army launched a major operation to recover Salahuddin. The fight lasted nearly a month and recovered the neighborhood, but the battle was not akin to the "mother of all battles." It didn't end the armed presence in Aleppo, as was announced at the time.
Afterward, the Nur al-Din al-Zanki Brigade announced that it was withdrawing from Tawhid and returning to the west Aleppo countryside, while Tawhid gunmen pressed forward and took control of the neighborhoods around the Hanano barracks, which they surrounded.
Then Jabhat al-Nusra revealed itself publicly and its gunmen stormed the Hanano barracks alongside Tawhid gunmen. But the Syrian army recovered the barracks with a force backed by T-82 tanks and with air and artillery support. Tawhid and Jabhat al-Nusra withdrew from the barracks after taking the weapons and ammunition stored there. Then the battle for Aleppo's old city started. Tawhid gunmen took up position there and Aleppo's historical markets were burned amid mutual accusations over who was responsible.
The relationship with the Muslim Brotherhood and the Salafists
The Muslim Brotherhood has fully supported Tawhid since its inception. Despite that, Tawhid commanders assert that "this doesn't mean that Tawhid is subordinated to the Brotherhood."
Opposition sources confirm to As-Safir that the denial by Tawhid officials is a "media denial." In reality, there is full coordination between Tawhid and the Brotherhood. Other sources consider Tawhid the primary armed wing of the Syrian Muslim Brotherhood, noting the close relationship between Haji Andan and some Brotherhood officials.
It is interesting that Tawhid has good relations with the Salafists, with whom Mareh coordinates. Mareh has close relations with the Salafists, including, for example, Kuwaiti National Assembly member Waleed al-Tabtabaie.
Opposition sources in the field confirmed to As-Safir that Tawhid is a unique example in terms of its ability to coordinate with parties having conflicting political orientations, whether internal or external.
These sources considered Tawhid a key factor in the convergence between political Islam represented by the Muslim Brotherhood, which is backed by Turkey and Qatar, and Salafist Islam, which is backed by Saudi Arabia and Kuwait.
It should be noted in this context that the Carnegie Institute report by researcher Rafael Lefevre quoted a non-Brotherhood activist, who helped finance the armed groups, as saying, "I have met with members of the al-Tawhid Brigade at a certain stage, when they took aid from the Muslim Brotherhood. But they also took [aid] from the Salafists. And they took [aid] from everyone. Their aim was not to form alliances, but they said 'we'll accept aid from whoever gives it to us.'"
It should also be noted that at one time Tawhid fighters wore black headbands on which was written "There is no God but God and Muhammad is the Messenger of God." But they later started wearing white headbands on which nothing was written.
The al-Tawhid Brigade today
Tawhid tried to take the form of an institution whose activities are not just military. So it created the Tawhid Medical Foundation and the Tawhid Media Foundation. Tawhid has 38 regiments, comprising nearly 11,000 gunmen. Tawhid also has 10,000 administrators.
Tawhid pays its members non-periodical payments in the form of rewards. The group's media is also very active. Some even call the group, "The Photography Brigade."
Opposition sources in the field told As-Safir that the group weakened in recent months and that its fighters lacked training and preparation and were not of high quality. Tawhid's role in the last six months was symbolic. Some factions that wished to avoid appearing in the media, because of their secretive nature, attributed their gains to Tawhid. That's what happened in the Brigade 80 battle, next to Aleppo's civilian airport.
Tawhid officials profess neutrality toward the rest of the brigades' differences. They boast of having good relations with everyone, which allows them to play the role of mediator in resolving disputes. The latest mediation was in the ongoing conflict between ISIS and the Northern Storm Brigade in Azaz.
Tawhid has its own prison and Sharia court. In August 2012, Tawhid formed the so-called Revolutionary Security Bureau. Two months later, an agreement was reached with the other brigades to grant the bureau broader powers. The bureau was given its own military unit, made up of gunmen contributed from each brigade, but they stayed members of their original units. When necessary, the bureau could get reinforcements, especially from Tawhid.
Tawhid seeks to enshrine Islamic rule in Syria. And it declares that "minorities should be treated like all other citizens."
More from Sahib Anjarini


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Knox & Son independent family funeral directors have been established in Warrington for over 100 years, and we still occupy the same premises on Orford Road, that we started out in all those years ago.
Through the generations we have learnt to adapt our services to suit the families of today whilst still retaining our traditional values and beliefs.
Managing Director Elizabeth Greenwood, following in the footsteps of her parents, Jim and Betty Mercer, strives to provide a unique and bespoke funeral to each family that requires our services.
"No two funerals are the same, families today have a much greater input into the service of their loved ones and we are very proud that we can provide such a vast range of options to make their loved one's funeral service truly unique"


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Speculated Vote results
Frank goes home
Tonight on the Live Feeds
Double Eviction tonight!! As mentioned in the last couple of TV episodes tonight will be a Double Eviction night, where two house guests dreams of winning the half a million dollars will come to an end.
Join OBB this weekend and try the Live Feeds FREE for 3 Days! —> Live Subscription Link
Actual Votes
- Dan Votes to Evict Frank
- Danielle Votes to Evict Frank
- Jenn Votes to Evict Joe
- Shane Votes to Evict Frank
Should there be a tie Ian will break it:
There is no tie, Ian does not need to vote.
Frank is evicted from the Big Brother House
Big Brother 14 Double Eviction Results
- First HOH Winner is Dan
- Nominations are Joe and Ian
- POV Winner is Ian
- POV Used YES
- Replacement Nomination Danielle
- JOE is evicted from the Big Brother House
- Second HOH Winner is IAN
Shane Votes to Evict Joe
Jenn Votes to Evict Joe
Ian Votes to Evict Joe
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Topman General Store
Time Out says
Friendly warning! We're working hard to be accurate. But these are unusual times, so please check that venues remain open.
Topman opened its first General Store in Spitalfields last year, selling the finest of the Arcadia menswear chain's apparel alongside handpicked pieces of designer and niche labels like Pendleton and Happy Socks. Unsurprisingly, with B-Store's Matthew Murphy and the excellent Topman creative director Gordon Richardson writing the stock list, product was tasteful and well presented – with all TM branding conspicuous by its absence. The idea worked beautifully in its spiritual home of indie east London, but it's been tweaked a bit for this new Covent Garden outpost. In sympathy with the slightly more upmarket surroundings, the store is a little less artfully weathered than its older brother, and a bit more Scandic in feel, with bright whitewashed walls and expensive-looking retro display cabinets from Newington Green vintage furnishers The Peanut Vendor. The product range also has a few nods to the less casual consumer, with smarter Topman Design tailoring, Swear shoes and John Smedley knits sitting alongside Pendleton rucksacks and denim jackets. Ten out of ten again, Topman. We'll say it again – isn't it time for a Topshop General Boutique for the girls?
Topman General Store
36-38 Earlham Street
|Tube: Covent Garden tube.
|Opening hours:
|Open 10am-7pm Mon-Sat 12noon-6pm Sun.
|Do you own this business?
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daily 03/15/2016
"My bully is a man to reckon with," I reckoned.
"I remember our dads both having to pick us up at the same time because we'd been fighting again," he said. "Neither of them angry, just disappointed, and how much worse their disappointment was, compared to their anger."
"Ever gone a week without a rationalization?"
As for learning on the job, Henry Kissinger wrote that high office "consumes intellectual capital; it does not create it. Most high officials leave office with the perceptions and insights with which they entered."
More recently, SCOTUS held that finding a parent in civil contempt and jailing them for failure to pay child support without first checking to see if that parent can actually pay is violation of due process.
Researchers say FAA is really overblowing risk posed by small drones | Ars Technica
Drones weighing more than 250 grams (a little more than half a pound) will have to be registered with the FAA, and there are restrictions on where they can be flown.
But an investigation last year by the Academy of Model Aeronautics (AMA) found that of the 764 near-miss incidents with drones recorded by the FAA, only 27 of them—3.5 percent—actually were near misses.
"On average, only 3 percent of reported small-bird strikes ever result in damage, compared to 39 percent of large-bird strikes," Dourado and Hammond reported. "Given the voluntary nature of strike reporting, the true percentage of strikes causing damage is probably much lower, as strikes that do not cause damage can be either missed or underreported."
Birds spend much more time in the air than consumer drones, which have a short battery life. Birds also don't necessarily avoid areas where airplanes are apt to hit them. Based on usage statistics, compared with bird behavior, the researchers estimated that for every 100,000 hours of flight time for drones weighing up to 2 kilograms, there would be 0.00000612 collisions causing damage to aircraft. "Or to put it another way," the pair wrote, "one damaging incident will occur no more than every 1.87 million years of 2kg UAS flight time."
And the frequency of injuries caused by drone collisions, they estimated, would be another two orders of magnitude smaller—happening once every 1.87 million years of operation. "This appears to be an acceptable risk to the airspace," they concluded.
Excel Waterfall Charts (Bridge Charts) – Peltier Tech Blog
Waterfall charts are commonly used in business to show how a value changes from one state to another through a series of intermediate changes.
Waterfall charts are often called bridge charts, because a waterfall chart shows a bridge connecting its endpoints. A simple waterfall chart is shown below:
The first approach most people try is to use a floating column chart, that is, a stacked column chart with the bottom column in the stack hidden to make the others float.
This tutorial shows how to create waterfall charts in Excel, including the specialized data layout needed, and the detailed combination of chart series and chart types required. This manual process takes time, can be prone to error, and soon becomes tedious. If you want to add data labels, tedium increases.
Waterfall – Peltier Tech Charts for Excel – Documentation
Making Waterfall Charts
Why Captain America: The First Avenger Is Unlike Any Other Marvel Movie
But The First Avenger still stands out for me because it really did something that none of the Marvel movies have really done, something that resonates as Captain America as a character celebrates his 75th anniversary this month.
The First Avenger embraced its comic book history, rooted in the Golden and Silver Ages of comics, in a way no other Marvel movie really has. That's not to say that the others have been unfaithful—they've taken the spirit of those stories and modernized them, as in Thor or Iron Man. Or in the case of Guardians, taken the basic premise and built something with its own, crazy tone.
Former cyber czar says NSA could crack the San Bernadino shooter's phone — arstechnica.com
He told National Public Radio's David Greene today that "encryption and privacy are larger issues than fighting terrorism," taking issue with the FBI's attempts to compel Apple's assistance.
Clarke added that if he was still at the White House, he would have told FBI Director James Comey to "call Ft. Meade, and the NSA would have solved this problem…Every expert I know believes that NSA can crack this phone." But the FBI wasn't seeking that help, he said, because "they just want the precedent."
"Compelling them to write code. And the courts have ruled in the past that computer code is speech."
Within the US government, we decided long ago that there are limits in what we're going to do in the war against terrorism."
Clarke noted that Comey and the Justice Department were not getting support in their case from the defense and intelligence communities.
"The FBI director [Comey] is exaggerating the need for this, and the Attorney General [Loretta Lynch] is letting him get away with it."
My PC Upgraded To Windows 10 Without Asking, Then Immediately Broke
This is how I want it to work.
I was on a much-needed staycation last week, a chance to recharge my batteries. What I didn't anticipate was spending half a day trying to figure out how Windows 10 got installed on my PC and why it broke everything.
"You've been signed in with a temporary profile," read an error message.


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Pacific University in the News: June 8-14, 2012
Education notes
(Door County Advocate [Wis.] © 06/14/2012) - Graduation hometown announcement: Kerriann (Bleck) Anderko [Pharmacy].
9 Algorithms that Changed the Future, Part 2
(Christianity Today © 06/13/2012) - Piece by Physics assistant professor Andrew Dawes.
How do you energize downtown Forest Grove?
(News-Times [Forest Grove] © 06/13/2012) - University a key presence in Forest Grove.
Music teacher finds rhythm as artist
(News-Times [Forest Grove], Portland Tribune © 06/13/2012) - Alumna Judy McIntosh Vatne (Music Education)
Corvallis Knights: Club coming back to Goss with two-game win streak, 4-0 shutout
(Corvallis Gazette-Times © 06/13/2012) - Boxer and baseball student-athlete Rob Dittrick.
WRA alum named Guggenheim Fellow
(Hudson Hub Times [Ravenna, Ohio] © 06/13/2012) - MFA in Writing instructor Joseph Millar.
Congratulations LHS Class of 2012
(Lebanon Express © 06/13/2012) - Lebanon High School valedictorian Andy Amick hopes to study chemistry at Pacific.
The chant for Chee-Ma-Wah
(Yamhill Valley News-Register [McMinnville] © 06/13/2012) - University mention: Chemawa Indian School.
Bremerton native will coach Black Hills boys basketball
(The Olympian [Olympia, Wash.] © 06/13/2012) - Alumnus and Men's Basketball student-athlete Jeff Gallagher.
Soroptimist International of Sedro-Woolley awards 10 scholarships
(Skagit Valley Herald [Mt. Vernon, Wash.] © 06/13/2012) - Future Boxer Emilie Moser.
Mauka Rotary awards scholarships
(West Hawaii Today [Kailua-Kona] © 06/13/2012) - Future Boxer Alec Lugo to study performing arts.
'We're all one big happy family here'
(Bonner County Daily Bee [Sandpoint, Idaho] © 06/12/2012) - Clark Fork High School valedictorian and future Boxer Claire McMahon.
Name Droppers
(The Davis Enterprise © 06/12/2012) - Graduation announcement: Shekema McCarthy (Integrative Physiology).
Community roundup: Snohomish lacrosse player named an All-American
(The Herald [Everett, Wash.] © 06/12/2012) - Future Boxer and Women's Lacrosse student-athlete Mahealani Wong.
St. Ignatius High School Class of 2012 Scholarships and Awards
(Lake County Leader Advertiser [Polson, Mont.] © 06/12/2012) - St. Ignatius HS graduate Sarah Bowers (Pacific University Presidential Scholarship $60,000).
Pacific University names spring graduates
(East Oregonian [Pendleton] © 06/12/2012) - Graduation announcements: Jordan Mittelsdorf, Sierra Brummett, Rebecca Baker, Jennifer English.
Aberdeen High awards & scholarships
(The Daily World [Aberdeen, Wash.] © 06/10/2012) - Aberdeen High School graduate Emily Penttila (Pacific University Music Talent Award, Pacific University Pacesetter Scholarship, Pacific University Presidential Scholarship).
Providence St. Vincent hosts preemie reunion, students create portrait of Hillsboro: Your Washington County
(The Oregonian online © 06/10/2012) - MFA in Writing spring readings advance.
CHS grads' awards, scholarships and plans
(Corvallis Gazette-Times © 06/09/2012) - Corvallis High School graduates Lorne Bulling (Pacific Pacesetters Scholarship, Pacific Trustees Scholarship) and Heidi Johnson (Pacific Trustee's Scholarship, Pacific Grant, Tabitha Brown Inspiration Award).
An anthropologist's view of who and what defines gay marriage
(The Oregonian © 06/08/2012) - Opinion piece by Sociology-Anthropology assistant professor Aaron Greer.
Sandy High's Rebecca Marvin maintains a 4.0, despite working nearly full-time: Academic Achievers 2012
(The Oregonian © 06/08/2012) - Sandy High School graduate considering Pacific's Pharmacy program.
Rogersville resident graduates from Pacific University
(South County Mail [Rogersville, Mo.] © 06/08/2012) - Graduation announcement Kimberly Carroll (Professional Psychology).
Campus News
(Marshfield News Herald [Wis.] © 06/08/2012) - Graduation announcement: Dana Hoehn (Professional Psychology).


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Heidi Garrett-Peltier
Heidi Garrett-Peltier is assistant research professor at the Political Economy Research Institute (PERI) at the University of Massachusetts, Amherst.
Articles by this author
Monday, November 12, 2012
Don't Drive Off the Fiscal Cliff
The U.S. economy is set to go off the so-called "fiscal cliff" at midnight on December 31, 2012. That's when various tax cuts for people at most income levels will expire. Days later, the federal budget will automatically be cut as the result of an agreement made by both parties last summer, when Congress was in a standoff over the debt ceiling. The deal reached by President Obama and leaders of Congress, called the Budget Control Act of 2011, enabled the federal government to raise its debt ceiling (permitting it to pays its bills) while in turn reducing future budgets.
Read more
Friday, May 11, 2012
Don't Buy the Spin: How Cutting the Pentagon's Budget Could Boost the Economy
Should the enormous US military budget—which is more than double the combined levels of military spending by China, the United Kingdom, France, Russia and Germany—be cut? This question is finally on the table, thanks to the winding down of combat activities in Iraq and Afghanistan and to Washington's obsession with tamping down the federal deficits that have arisen from the Great Recession.
Read more
Friday, March 05, 2010
Why Military Keynesianism is NOT the Solution
The United States is currently preparing to send 30,000 additional troops to Afghanistan by summer 2010. Military contractors, deeply integrated into the U.S. economy, will continue to prosper and profit from increased military spending resulting from this surge of troops. At a time when unemployment in the domestic economy remains near 10%, it may seem convenient to fall back on the principle of military Keynesianism: War is good for the economy.
Read more
Friday, March 14, 2008
The Wages of Peace
There is no longer any doubt that the Iraq War is a moral and strategic disaster for the United States. But what has not yet been fully recognized is that it has also been an economic disaster. To date, the government has spent more than $522 billion on the war, with another $70 billion already allocated for 2008.
Read more


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X-Prize Foundation answers my tricorder competition complaints
Second in a series. This message from the X-Prize Foundation is in response to the letter I sent Qualcomm's CEO.
They seem to feel the contest is fine as-is and my objections are without merit.
Dear Bob,
I am the Senior Director in charge of this competition and I appreciate receiving your letter of interest dated January 11. First, let me offer you my highest level of encouragement for your creation of a SIDS monitoring device. As you know, medical technology is one of the most difficult areas to make significant progress in. To make something really work and pass through all the regulatory hurdles in this space is challenging as you point out. Second, my sincere personal condolences on the loss of your child. I understand and respect your total commitment to solve this challenging problem and admire your dedication and passion to address this urgent need.
We announced the Qualcomm Tricorder X PRIZE in January 2012 and spent a year refining the guidelines and structure of the competition, which includes the winning parameters, registration fees, rules and a timeline. The guidelines were finalized and released this month after receiving input from the scientific and medical communities, companies working in this space, and the general public. We are asking teams to develop a medical device that will allow consumers to diagnose a set of 15 diseases and monitor 5 vital signs, independent of a healthcare provider or facility. While we recognize that there are a number of unique new technologies, including yours, that address important public health concerns, we could not include every one of them in this competition. We did choose a range of core and elective conditions that are widely recognized as being significant for public health in North America and also offered a wide range of sensing and interpretive challenges.
As of today there isn't an integrated personal health device on the market that does everything that we're requiring in the guidelines. That is the essence of the competition and sets the stage for a unified solution that can capture data from many types of sensors, potentially including yours. As with many innovation competitions and Prizes, there is a registration fee required to participate. The registration fee, which is $5,000 until April 10th, helps us cover operational expenses such as numerous team and judging summits, ongoing communications to many stake holders, comprehensive device testing and judging processes that are essential to staging a fair and objective competition.
Please realize that we are a competition that intends to drive innovation and help to usher in a new digital health marketplace. We are not investors and in fact, we are not even the Judges who will act totally independent of us in determining the finalists. Our goal is stimulate an influx of consumer devices on the market in the near future. Even if you decided not to compete, the overall effect of these competitions will help to lift all boats in the digital health space, including yours we believe.
I encourage you to consider entering the Qualcomm Tricorder X PRIZE and/or Nokia Sensing X CHALLENGE, or join a current pre-registered team and incorporate your device into their submission. Although SIDS is not one of the defined conditions in the requirements it does not mean that the inclusion of your technology would not be advantageous to existing teams who all seek to commercialize their solutions. Inventing, developing, funding and bringing to market medical technology is a very difficult endeavor and a team approach may help. At the X PRIZE Foundation, one of our jobs is to provide a forum for sharing ideas, concepts and new technologies that might have otherwise gone unnoticed. That has been a guiding principle of this and all our competitions. We hope that you will consider becoming involved on this basis.
If you have additional questions or would like to speak further, please don't hesitate to contact me.
Mark Winter
Senior Director, Qualcomm Tricorder X PRIZE and Nokia Sensing X CHALLENGE
Reprinted with permission
Photo Credit: tanewpix/Shutterstock


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Maker Movement
The maker movement is bridging a gap in the research world as it is making even the most complex designs accessible to researcher and citizen alike.
The overlapping open-source, do-it-yourself, and maker movements are targeted at making technology cheaper and more accessible as they draw on the expertise, enthusiasm and support of the 'crowd.' While the open-source movement builds a virtual community around project "blueprints," the maker movement focuses on providing access to the manufacturing equipment, community and education necessary to put those designs into action. Makerspaces can be hosted virtually anywhere, all united around the philosophy of sharing the capacity to innovate.
UMass Amherst graduate students Don Blair and Ben Gamari (Physics) have found that this methodology enhances their research, allowing them to tinker with and fine-tune research equipment at a fraction of the cost. Employing their respective expertise in networking and computer programming, they began brainstorming new ways to take measurements, ways to design the equipment so that anybody willing to learn could make it. They began attending open-source, maker workshops and seminars and then put together some of their own.
The movement is bridging a gap in the research world as it is making even the most complex designs accessible to researcher and citizen alike. Members of the community are sharing ingenious techniques to repair expensive instruments, allowing their colleagues to more quickly fix issues that arise and spend more of their time on the science at-hand.
"We both realized, especially in academia and research, that a lot of the instrumentation is incredibly expensive and is not easy to use," Gamari says. "People can become disconnected from the instruments from which they take their data."
Blair and Gamari are working with the Massachusetts Water Resources Research Center (WRRC) and stakeholders in the region, gathering a local network of open-source enthusiasts as they work to develop an inexpensive, reproducible device for water quality monitoring. Pollution can come in many forms and is not always easily tracked—the more monitoring devices in bodies of water at various points, the more easily various sources of pollution can be identified. By making water quality monitoring technology more accessible, Blair, Gamari and the team are empowering the greater community to take stock in the waters that run through their backyard.
"It makes for better science, because you're reproducing results in a wider context—and it also democratizes science," Blair says.
UMass Amherst faculty as well as students are coming together to innovate and participate in the maker movement. Steven Brewer (Biology), Charles Schweik (Environmental Conservation and Public Policy) and Paula Rees (Engineering, WRRC director) have joined forces to organize a series of innovation workshops within the local community. Workshops range from showing middle school-aged students and their parents how to work with the Arduino—an open-source computer board originally designed for teaching beginner computer programming classes—to more advanced prototyping. These models serve as gateways to a nearly infinite array of innovations. An important goal is to provide students and community members a place where they can explore technology with some support. Their work is fostering a next-generation of tinkering, do-it-yourselfers that can innovate with today's technology to solve tomorrow's problems.
To increase interest in STEM (science, technology, engineering and math) among middle school students, Rees, (also the director of the College of Engineering Diversity Programs Office) has brought teams of UMass students to middle school classrooms in nearby Holyoke and Springfield to work with another prototyping platform—E-textiles—and to solve a variety of engineering problems. E-textiles, or "smart fabrics," are fabrics that enable embedded digital components and are therefore used for wearable computing. This project and others like it infuse "Arts" into the commonly used STEM acronym, resulting in the term STE(A)M. Last year, Blair worked with an afterschool program in Amherst to push the kids farther into product development. Rees, Blair, Brewer, and Schweik hope that by infusing science education with more creative elements, they can show students that successful science requires both sides of the brain.
"It's so great to talk to the middle school students," Blair says. "They don't have any boundaries as to what's possible."
The team was recently awarded an internal Public Service Endowment Grant to continue this work in Amherst with an afterschool program that will promote do-it-yourself creativity and encourage students to find innovative solutions to problems they identify in their own lives. Together with Amherst Media, they are working to develop a program that introduces kids to the process of posing research questions. They have begun teaching groups to build do-it-yourself (DIY) based hardware instrumentation and will soon show them how to use these instruments to conduct field research, as well as analyze the resulting data. There will also be opportunities to build DIY-based electronics "just for fun"— earrings that light up or a creative bike light, for example. The grant will help the team allocate an actual makerspace for the community to share. The space will conjoin scattered resources throughout the community. It will be a space where UMass students can do service-learning outreach to help their younger counterparts and a space for five-college makers to regularly come together.
With guidance from Rees and instruction from Professors David McLaughlin and Baird Soules, engineering undergraduates are participating in the movement. The Electrical and Computer Engineering Department recently built a "Mach 5" facility, directed by Soules, which students use as a makerspace of sorts. In one of McLaughlin's systems engineering classes, a group of students worked with middle school students to build a GPS-enabled collar for pets that would enable their owners to track their whereabouts.
Rees is working with Schweik, Brewer, Blair and others on campus to more broadly apply this kind of open-minded approach to innovation.
"By setting the spark in students at a young age, the hope is that more students will come into the engineering program with a creative, innovative mindset," Rees says.
Amanda Drane'12
Photos: Amherst Media


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The page you requested is no longer available.
We made the decision to shut down Xero Personal (also provided as BNZ Money Map) in February 2015.
As we communicated, all customer data was permanently removed.
Xero no longer offers a personal finance product, but we can recommend PocketSmith.
This offers functionality similar to Xero Personal.
The reasons we discontinued Xero Personal can be found in this blog post:
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In a realignment of its US network portfolio, Discovery Communications has announced that Eileen O'Neill as Group President of the Discovery Channel and has been given oversight of Science Channel and Velocity.
TLC, which O'Neill is credited with turning around, has been given to the care of Marjorie Kaplan, who becomes Group President of TLC and Animal Planet, while Henry Schleiff adds O'Neill's Discovery Fit & Health network to his watch, as Group President of that network and Investigation Discovery, Destination America, and American Heroes Channel.
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