Stiffening while drying

We present two models for the drying of waterborne paints, which consist of non-volatile latex particles suspended in water. One model considers the water and latex density in a layer as a function of time. Water evaporation at the surface represents the drying. This model results in a one-dimensional free boundary problem, which is solved numerically. Extensions to the model are given that describe the stiffening of the paint. A second model is a particle based dynamical simulation where latex particles form a network through which water particles move. A thin slab of the suspension in a three-dimensional box is studied. Water particles escaping the slab at the surface represent the drying, progressing network formation the stiffening of the paint. Both models allow for validation with material properties as determined experimentally on real coatings

A systems approach to the process dynamics of interpersonal selling in the financial services industry

The Financial Services Industry (FSI) in South Africa is currently under severe criticism for the quality of service it provides to its customer base. Customer dissatisfaction expressed through individuals, (See Appendix A) consumer bodies and members of parliament has resulted in the draft and approval of three new bills in parliament, which will protect the rights of customer

Direct electronic measurement of Peltier cooling and heating in graphene

Thermoelectric effects allow the generation of electrical power from waste heat and the electrical control of cooling and heating. Remarkably, these effects are also highly sensitive to the asymmetry in the density of states around the Fermi energy and can therefore be exploited as probes of distortions in the electronic structure at the nanoscale. Here we consider two-dimensional graphene as an excellent nanoscale carbon material for exploring the interaction between electronic and thermal transport phenomena, by presenting a direct and quantitative measurement of the Peltier component to electronic cooling and heating in graphene. Thanks to an architecture including nanoscale thermometers, we detected Peltier component modulation of up to 15 mK for currents of 20 $\mu$A at room temperature and observed a full reversal between Peltier cooling and heating for electron and hole regimes. This fundamental thermodynamic property is a complementary tool for the study of nanoscale thermoelectric transport in two-dimensional materials.Comment: Final version published in Nature Communications under a Creative Commons Attribution 4.0 International Licens

Rigorously computing symmetric stationary states of the Ohta-Kawasaki problem in three dimensions

In this paper we develop a symmetry preserving method for the rigorous computation of stationary states of the Ohta-Kawasaki partial differential equation in three space dimensions. By preserving the relevant symmetries we achieve an enormous reduction in computational cost. This makes it feasible to construct computer-assisted proofs of complex three-dimensional structures. In particular, we provide the first existence proofs for both the double gyroid and body centered cubic packed sphere solutions to this problem

The Threat Effect of Participation in Active Labor Market Programs on Job Search Behavior of Migrants in Germany

Labor market programs may affect unemployed individuals' behavior before they enroll. Such ex ante effects may differ according to ethnic origin. We apply a novel method that relates self-reported perceived treatment rates and job search behavioral outcomes, such as the reservation wage or search intensity, to each other. We compare German native workers with migrants with a Turkish origin or Central and Eastern European (including Russian) background. Job search theory is used to derive theoretical predictions. We examine the omnibus ex ante effect of the German ALMP system, using the novel IZA Evaluation Data Set, which includes self-reported assessments of the variables of interest as well as an unusually detailed amount of information on behavior, attitudes and past outcomes. We find that the ex ante threat effect on the reservation wage and search effort varies considerably among the groups considered.unemployment duration, immigrants, active labor market policy, policy evaluation, reservation wage, program evaluation, expectations, search effort

Long spin relaxation times in wafer scale epitaxial graphene on SiC(0001)

We developed an easy, upscalable process to prepare lateral spin-valve devices on epitaxially grown monolayer graphene on SiC(0001) and perform nonlocal spin transport measurements. We observe the longest spin relaxation times tau_S in monolayer graphene, while the spin diffusion coefficient D_S is strongly reduced compared to typical results on exfoliated graphene. The increase of tau_S is probably related to the changed substrate, while the cause for the small value of D_S remains an open question.Comment: 16 pages, 3 figures, 1 tabl

The threat effect of participation in active labor market programs on job search behavior of migrants in Germany

Labor market programs may affect unemployed individuals’ behavior before they enroll. Such ex ante effects may differ according to ethnic origin. We apply a novel method that relates self-reported perceived treatment rates and job search behav­ioral outcomes, such as the reservation wage or search intensity, to each other. We compare German native workers with migrants with a Turkish origin or Central and Eastern European (including Russian) background. Job search theory is used to de­rive theoretical predictions. We examine the omnibus ex ante effect of the German ALMP system, using the novel IZA Evaluation Data Set, which includes self-reported assessments of the variables of interest as well as an unusually detailed amount of in­formation on behavior, attitudes and past outcomes. We find that the ex ante threat effect on the reservation wage and search effort varies considerably among the groups considered.Immigrants; policy evaluation; reservation wage; search effort; expectations; unemploy­ment duration; program evaluation; active labor market policy.