Making it Work: Formalizing Your Volunteer Program is Worth the Effort

Formalizing your volunteer program is worth the effor

Making it Work: Formalizing Your Volunteer Program is Worth the Effort

Formalizing your volunteer program is worth the effor

Ab initio electronic-structure calculations on the Nb/Cu multilayer system

Ab initio electronic-structure calculations are reported for coherent and incoherent Nb/Cu multilayem. An incoherent unit cell describing three Nb BCC (110) layers and three Cu FCC (111) layers is constructed for the layers in the Nishiyama- Wasserman orientation and with relaxed atomic positions at the interface. It is found that the total density of states is a combination of the broadened DOS curves of the parent metals and that at the interface Nb has a decreased, and Cu has an increased, density of states at the Fermi energy. These results are in agreement with experimetital results and for Nb can be explained by a broadening of the density of states. Possible coherency for small modulation wavelengths is investigated by calculating the total energies for overall BCC [110] and overall FCC [111] Nb/Cu multilayers consisting of one layer of each metal and comparing these with the total energy results of the incoherent structure. The positive interface energy found for the Nb/Cu system favours the incoherent multilayer over the coherent multilayers, where a positive structural energy is also involved

A real-time hybrid neuron network for highly parallel cognitive systems

For comprehensive understanding of how neurons communicate with each other, new tools need to be developed that can accurately mimic the behaviour of such neurons and neuron networks under 'real-time' constraints. In this paper, we propose an easily customisable, highly pipelined, neuron network design, which executes optimally scheduled floating-point operations for maximal amount of biophysically plausible neurons per FPGA family type. To reduce the required amount of resources without adverse effect on the calculation latency, a single exponent instance is used for multiple neuron calculation operations. Experimental results indicate that the proposed network design allows the simulation of up to 1188 neurons on Virtex7 (XC7VX550T) device in brain real-time yielding a speed-up of x12.4 compared to the state-of-the art

Theoretically predicting the solubility of polydisperse polymers using Flory-Huggins theory

Polydispersity affects physical properties of polymeric materials, such as solubility in solvents. Most biobased, synthetic, recycled, mixed, copolymerized, and self-assembled polymers vary in size and chemical structure. Using solvent fractionation, this variety in molecular features can be reduced and a selection of the sizes and molecular features of the polymers can be made. The significant chemical and physical dispersity of these polymers, however, complicates theoretical solubility predictions. A theoretical description of the fractionation process can guide experiments and material design. During solvent fractioning of polymers, a part of the polydisperse distribution of the polymers dissolves. To describe this process, this paper presents a theoretical tool using Flory-Huggins theory combined with molecular mass distributions and distributions in the number of functional groups. This paper quantifies how chemical and physical polydispersity of polymers affects their solubility. Comparison of theoretical predictions with experimental measurements of lignin in a mixture of solvents shows that multiple molecular features can be described well using a single set of parameters, giving a tool to theoretically predict the selective solubility of polymers.</p

Sputum Induction in Children Is Feasible and Useful in a Bustling General Hospital Practice

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The Jeroen Bosch Hospital funded this study.Peer reviewedPublisher PD

Predicting Multi-Component Phase Equilibria of Polymers using Approximations to Flory–Huggins Theory

The rational development of sustainable polymeric materials demands tunable properties using mixtures of polymers with chemical variations. At the same time, the sheer number of potential variations and combinations makes experimentally or numerically studying every new mixture impractical. A direct predictive tool quantifying how material properties change when molecular features change provides a less time- and resource-consuming route to optimization. Numerically solving Flory–Huggins theory provides such a tool for mono-disperse mixtures with a limited number of components, but for multi-component systems the large number of equations makes numerical computations challenging. Approximate solutions to Flory–Huggins theory relating miscibility and solubility to molecular features are presented. The set of approximate relations show a wider range of accuracy compared to existing approximations. The combination of the analytical, lower-order, and more accurate higher-order approximations together contribute to a broader applicability and extensibility of Flory–Huggins theory.</p

Ab initio electronic-structure calculations on the Nb/Ta multilayer system

Ab initio electronic-structure calculations are performed for Nb/Ta multilayers with small modulation wavelengths in the [100], [110] and [111] BCC modulation directions. The [110] modulated Nb/Ta multilayer with the smallest modulation wavelength was also calculated with an 8% increased modulation wavelength on the one hand, with an undisturbed structure but containing 50% interstitial hydrogen on the other hand, and with a combination of both. The ease with which Nb/Ta multilayers can be grown in different modulation directions is understood from total energy calculations which show energy differences of less than 1 mRyd between the various directions. Further, it is found that interstitial hydrogen lowers the density of states at the Fermi level and that, but to a lesser extent, the lattice expansion on hydrogenation raises the density of states at the Fermi level. The net effect of a lowering of the density of states at the Fermi level is in agreement with the measured reduction of the superconducting critical temperature on hydrogenation