Reference values of the chronoamperometric response at cylindrical and capped cylindrical electrodes

This work provides accurate solutions of the cylinder flux function I(0,1;T), first solved by Jaeger and Clarke, which can serve as reference values for electrochemical amperometric diffusion limited currents at a cylinder, as well as heat fluxes under equivalent conditions (fixed temperature at the cylinder surface). For the capped cylinder of varying lengths, reference values of time-dependent electrochemical currents are provided. Steady state currents at capped cylinders are presented and a function is provided that fits the simulated values to within 1%. All of these are more accurate than in previous works.     

An analytical model for solute mixing in surcharged manholes

A mathematical model has been developed to describe solute mixing in surcharged manholes using the submerged jet theory. The model has been applied for straight-through flow manholes and for manholes with a difference in the level of the inlet and outlet pipes. The model is applicable to dissolved substances, i.e. the model has not been validated for high sediment concentrations (above 1 g/l) and care should be taken in such cases. Simulation results from the new model are compared with laboratory measurements and are further compared to conventional modelling techniques currently available in commercial software specially developed for modelling the water quality in sewers. The results prove that the new model produces considerably better results compared to the traditional assumption of full mixing in a manhole. The new model compares well to the laboratory measurements and hence improves the accuracy of modelling soluble pollutant transport in sewers. The applicability of the new modelling approach is discussed and further studies are recommended.     

Micro-fibre and ultra-micro-fibre cloths, their physical characteristics, cleaning effect, abrasion on surfaces, friction, and wear resistance

The properties of 12 micro-fibre cloths and two ultra-micro-fibre cloths were studied and compared with conventional cleaning methods. The cloths made from micro-fibre and ultra-micro-fibre had very good cleaning effect. Scrubbing Plexiglas caused pitting and scratch marks on the Plexiglas surface with the largest damage being caused in dry condition. All the cloths tested were wear resistant. Most of the cloths showed high friction against the surfaces in damp condition. Micro- and ultra-micro-fibre cloths are good alternatives to conventional methods for cleaning interior surfaces. Furthermore, good cleaning results can be achieved without any use of polluting cleaning chemicals.     

丹麦区域供热水处理标准简介

在丹麦,许多区域供热系统都曾经有过由于有垢形成或由于腐蚀而造成的管道破坏及能源损失,这是由于水处理不充分或缺乏水处理造成的。当原有的区域供热系统被更新的时候,在某些部位需要修理之前将水处理水平提高通常是非常重要的。因为只有水质符合要求我们才能使系统能使用更长时间。１９８８年,ＤａｎｓｋｅＦｊｅｒｖａｒｍｅｖｅｒｋｅｒｓＦｏｒｅｎ－ｉｎｇ（丹麦区域供热协会）为适应发展需要提供了如今丹麦区域供热系统应用的给水和循环水的建议。这些标准应用的温度范围为３５℃至１８０℃,而且必须强调的是系统中不能有铝材存…     

Formulation and sequential numerical algorithms of coupled fluid/heat flow and geomechanics for multiple porosity materials

We extend constitutive relations of coupled flow and geomechanics for the isothermal elastic double porosity model by Berryman [Journal of Engineering Mechanics ASCE 2002; 128(8):840–847] in the previous study to those for the nonisothermal elastic/elastoplastic multiple porosity model, finding coupling coefficients and constraints of the multiple porosity model and determining the upscaled elastic/elastoplastic moduli as well as relations between the local strains of all materials within a gridblock and the global strain of the gridblock. Furthermore, the coupling equations and relations between local and global variables provide well‐posed problems, implying that they honor the dissipative mechanism of coupled flow and geomechanics. For numerical implementation, we modify the fixed‐stress sequential method for the multiple porosity model. From the a priori stability estimate, the sequential method provides numerical stability when an implicit time‐stepping algorithm is used. This sequential scheme can easily be implemented by using a modified porosity function and its porosity correction. In numerical examples, we observe clear differences among the single, double, and multiple porosity systems, and the multiple porosity model can reflect the substantial heterogeneity that exists within a gridblock. We also identify considerably complicated physics in coupled flow and geomechanics of the multiple porosity systems, which cannot accurately be detected in the uncoupled flow simulation. Copyright © 2012 John Wiley & Sons, Ltd.     

In situ TEM creation and electrical characterization of nanowire devices

We demonstrate the observation and measurement of simple nanoscale devices over their complete lifecycle from creation to failure within a transmission electron microscope. Devices were formed by growing Si nanowires, using the vapor-liquid-solid method, to form bridges between Si cantilevers. We characterize the formation of the contact between the nanowire and the cantilever, showing that the nature of the connection depends on the flow of heat and electrical current during and after the moment of contact. We measure the electrical properties and high current failure characteristics of the resulting bridge devices in situ and relate these to the structure. We also describe processes to modify the contact and the nanowire surface after device formation. The technique we describe allows the direct analysis of the processes taking place during device formation and use, correlating specific nanoscale structural and electrical parameters on an individual device basis.     

Thin films of two functional oxides patterned laterally by soft lithography

Thin films of two laterally patterned functional oxides of uniform thickness were obtained in a two-step soft-lithographic micromolding process. CoFe(2)O(4)/ZnO and CoFe(2)O(4)/BaTiO(3) dual-phase patterns were fabricated. The films showed good replication of the pattern that was defined in the first patterning step. X-ray diffraction showed that the films consisted of two distinct phases, and magnetic force microscopy showed that the compounds were laterally separated, the separation pattern being the same as that of the initial soft-lithographic process. The films exhibited slight height variations near the edges of the phases, which were introduced in the first deposition step and were not fully compensated in the second deposition step. The films are sufficiently smooth to allow fabrication of multilayer structures.     

PH-dependent self-assembly of the short Surfactant-like peptide KA6

Self-assembly of amphiphilic peptides designed during the last ten years by different research groups lead to a large variety of 3D-structures that already found applications in e.g., for stabilization of large protein complexes, cell culturing systems etc. We present synthesis and characterization of a novel amphiphilic peptide KA6 that exhibits clear charge separation controllable by the pH of the environment. The self-assembly in this system is largely governed by electrostatic interaction, thus a change in pH will not only lead to a change in critical micellar concentration (CMC) of the peptide but also to the changes in micellar structure as revealed by atomic force microscopy (AFM) and circular dichroism (CD) study. At basic pH the micellar structure inverts exposing the opposite end of the peptide chain to the solution. This interesting phenomenon could provide basis for novel pH sensitive materials including drug delivery and controlled release systems.     

Stacks of functional oxide thin films patterned by micromolding

Stacks of up to five relief patterned functional oxide thin films were obtained by a low-cost and low-tech soft-lithographic patterning technique. Micromolding was used to pattern a film of a metal-organic precursor solution for Y-stabilized ZrO(2) (YSZO). Subsequent drying and pyrolysis yielded a line-patterned YSZO film. The process was repeated up to four times with a precursor solution for BaTiO(3) on top of the YSZO film, resulting in stacks of YSZO and BaTiO(3) lines with well-defined edges. This approach presents a step forward on the way to a versatile additive micropatterning technique with which simple multi-material device structures can be fabricated in a reliable, fast, and cost-effective manner.     

Sex differences in neuropsychological performance and social functioning in schizophrenia and bipolar disorder.

Objective: To investigate sex differences in neurocognition and social functioning in schizophrenia and bipolar disorder and the possible role of sex as a moderator of this relationship. Method: Participants with schizophrenia (60 women/94 men), bipolar I disorder (55 women/51 men), and healthy controls (158 women/182 men) were assessed with an extensive neuropsychological test battery and a social functioning questionnaire. Results: We found significant main effects of sex for neuropsychological tests (p