From a top-down to a bottom-up urban discourse: (re) constructing the city in a family-inclusive way

This paper focuses on urban discourses as powerful instruments intertwined with the dialectic of inclusion and exclusion. First, three dominant contemporary urban discourses developed in the field of urban planning are scrutinized on their inclusiveness of families and daily family life. The attractive city, the creative city and the city as an emancipation machine are examples of urban discourses communicated top-down via reports, debates and media attention. It is argued that these three discourses do not address families as urban citizens nor the very notion of reproduction and its daily manifestation. The exclusionary character of contemporary urban discourses does not only result in a neglect of urban families, it also legitimates non-intervention when it comes to family issues. This conclusion activated the search for an alternative discourse as expanded in the second part of the paper. This alternative discourse is constructed from the bottom-up and is rooted in the day-to-day experiences of urban families themselves. It is a refined discourse, with interrelated geographical scales including the city as a whole, the neighbourhood, the street and the home. This is a city that integrates—as families themselves do—the different domains of life. The city is appreciated for its qualities of proximity, the neighbourhood for its ethnically mixed children’s domains, the street as an urban haven and the house as the place that accommodates private life for each member of the family. This alternative discourse is called the balanced city. The empirical basis is drawn from middle-class urban families in Rotterdam, The Netherlands.     

A model for cryosectioning based on the morphology of vitrified ultrathin sections

Electron microscopy of vitrified ultrathin sections allows cell ultrastructure to be studied in the hydrated state. Sectioning of the frozen material is, however, a limiting step, since the cutting forces cause severe mechanical deformation. In order to address this problem, we have investigated the surface of cryosections. It is shown that cryosections have two fundamentally different surfaces. One surface is rough, deformed by cutting-induced deformation lines which are orientated perpendicular to the cutting direction. The other surface, in comparison, is not affected by those deformation lines. Except for knife marks it is smooth. In order to explain the observations, the following model is proposed. The rough relief corresponds to the former block face. Its roughness originates from material that is squeezed out of the section plane when the section is compressed in the cutting direction and bent away from the specimen block. The smooth section surface is the surface in contact with the knife during the sectioning. This contact keeps the surface smooth while imprinting the knife marks.     

State of the art of geothermal reservoir simulation

Computer modeling of geothermal systems has become a mature technology with application to more than 100 fields world-wide. Large complex three-dimensional models having computational meshes with more than 4000 blocks are now used routinely. Researchers continue to carry out fundamental research on modeling techniques and physical processes in geothermal systems. The new advances are adopted quickly by the geothermal industry and have also found application in related areas such as nuclear waste storage, environmental remediation and studies of the vadose (unsaturated) zone. The current state-of-practice, recent advances and emerging trends in geothermal reservoir simulation are reviewed.     

On production behavior of enhanced geothermal systems with CO2 as working fluid

Numerical simulation is used to evaluate the mass flow and heat extraction rates from enhanced geothermal injection–production systems that are operated using either CO₂ or water as heat transmission fluid. For a model system patterned after the European hot dry rock experiment at Soultz, we find significantly greater heat extraction rates for CO₂ as compared to water. The strong dependence of CO₂ mobility (=density/viscosity) upon temperature and pressure may lead to unusual production behavior, where heat extraction rates can actually increase for a time, even as the reservoir is subject to thermal depletion. We present the first ever, three-dimensional simulations of CO₂ injection–production systems. These show strong effects of gravity on the mass flow and heat extraction due to the large contrast of CO₂ density between cold injection and hot production conditions. The tendency for preferential flow of cold, dense CO₂ along the reservoir bottom can lead to premature thermal breakthrough. The problem can be avoided by producing from only a limited depth interval at the top of the reservoir.     

Untersuchung des Passivierungsmechanismus von Eisen in Phosphatelektrolyten an erosiv beanspruchten Oberflächen

Investigation into the passivation mechanism of iron in phosphate electrolytes on surfaces exposed to erosive attack On iron electrodes in neutral phosphate electrolytes by continuous solid particle impingement a reaction layer is formed within the transition potential region under anodic polarization. XPS and AES investigations show that the reaction layer formed under impingement will be replaced by an oxide layer during the transition into the passive state under simultaneous decrease of the layer thickness. The active/passive transition in phosphate electrolytes may be attached to the equilibrium potential of the reaction . According to this thermodynamic interpretation of both the active/passive transition and the passive/active transition, respectively on iron in presence of phosphate ions may be described as the Fe(II)/Fe(III)-redox reaction with two solid phases, the iron(II)-phosphate phase and the iron(III)-oxide phase. The increase of the interfacial dynamic processes at the solid/liquid interface causes in consequence of the solid particle impingement that thermodynamic laws govern the course of reactions.     

Fabrication and characterization of PEDOT nanowires based on self-assembled peptide nanotube lithography

In this article we demonstrate the use of self-assembled peptide nanotube structures as masking material in a rapid, mild and low cost fabrication of polymerized p-toluenesulfonate doped poly(3,4-ethylenedioxythiophene) (PEDOT:TsO) nanowire device. In this new fabrication approach the PEDOT:TsO nanowire avoids all contact with any organic solvents otherwise traditionally used in clean room fabrication. This can be achieved due to the intriguing properties of the self-assembled peptide nanotubes utilized as a dry etching mask for the patterning of the PEDOT:TsO nanowire. The peptide nanotubes, despite remaining stable during the reactive ion etching procedure, can be dissolved rapidly in water afterwards. The fabricated PEDOT:TsO nanowire devices exhibit excellent electrical characteristics. Finally, the potential of PEDOT:TsO nanowires as temperature sensors has been demonstrated and the high resolution of the sensor was illustrated.     

Einflu? von Ethanol auf den Trocknungsverlauf und die Makrostruktur eines Einzel-Zellmaterials aus Apfelparenchym (Sorte Granny Smith)

Ethanol pre-treated apple parenchyma cells are dried in a laboratory vacuum dryer. Various ethanol contents (75 to 95% m/m) and moisture contents (2 to 15 g ethanol-water-mixture per g dry mass) of the cells were adjusted before drying and the influence of these factors on drying behaviour as well as the related structural changes are studied. The initial ethanol content was found to have a significant influence on both, drying behaviour and macrostructure of the dried material. In the case of a low initial value, the ethanol content during drying already drops at moisture contents of about 0.5–1.5 g/g. As a consequence the residual particle moisture consists mainly of water at the end of drying. In contrast to high initial ethanol contents, cells at a low initial ethanol content become strongly deformed on drying. The porosity of the dried material also decreases in the latter case, relatively large and stable aggregates are formed and the water binding capacity of the dried product has diminished on a large scale. The initial moisture content influences the drying behaviour especially on applying low initial ethanol contents. If the initial moisture content is reduced the drop of the ethanol content is shifted towards the end of the drying process. The influence of initial moisture content on macrostructure, however, was found to be small compared with the effect of the initial ethanol content.

     

采用硬件加速可以让MicroBlaze发挥更为强劲的处理能力

在实际应用中,有许多算法可以转化为纯硬件来加速您的处理器.平均标准偏差算法、给定时间内创建最小值或最大值、滤波器以及FFT均属于可轻松移植到硬件上的典型算法.不过诸如位反转等一些不常见的算法可采用合适的硬件加速器也能移植到硬件上.     

Enhancing the Selectivity and Transparency of the Electron Contact in Silicon Heterojunction Solar Cells by Phosphorus Catalytic Doping

An intrinsic hydrogenated amorphous silicon (a-Si:H(i)) film and a doped silicon film are usually combined in the heterojunction contacts of silicon heterojunction (SHJ) solar cells. In this work, a post-doping process called catalytic doping (Cat-doping) on a-Si:H(i) is performed on the electron selective side of SHJ solar cells, which enables a device architecture that eliminates the additional deposition of the doped silicon layer. Thus, a single phosphorus Cat-doping layer combines the functions of two other layers by enabling excellent interface passivation and high carrier selectivity. The overall thinner layer on the window side results in higher spectral response at short wavelengths, leading to an improved short-circuit current density of 40.31 mA cm⁻² and an efficiency of 23.65% (certified). The cell efficiency is currently limited by sputter damage from the subsequent transparent conductive oxide fabrication and low carrier activation in the a-Si:H(i) with Cat-doping. Numerical device simulations show that the a-Si:H(i) with Cat-doping can provide sufficient field effect passivation even at lower active carrier concentrations compared to the as-deposited doped layer, due to the lower defect density.