Porous Perovskite Fibers – Preparation by Wet Phase Inversion Spinning and Catalytic Activity

Porous perovskite (LaMnO₃) fibers were prepared by means of wet phase inversion spinning. The influence of different spinning procedures, slurry and coagulation bath composition on fiber shape and pore morphology was studied. The catalytic activity of the prepared fibers was tested for carbon monoxide oxidation as a model reaction in a differential recycle reactor. The results revealed that by suitable choice of process conditions porous catalytically active fibers can be prepared. Catalytic measurements confirmed that the catalytic fibers exhibit an open structure that allows full utilization of the catalytically active surface without intraparticle diffusional limitations.     

Experiments and Simulations on the Cleaning of a Swellable Soil in Plane Channel Flow

ABSTRACT

The cleaning behavior of a soil with physical properties that depend on the wetting time is studied experimentally via the local phosphorescence detection method and simulated numerically in fully developed plane channel flow for Reynolds numbers up to 30,000. A computationally inexpensive general cleaning model is proposed, adopting an existing removal model and coupling it to the turbulent flow field. The influence of the soil on the flow is neglected and the transient behavior of the soil during cleaning is modeled in the form of a transient Dirichlet boundary condition. This approach is innovative for computational fluid dynamics of this phenomenon. The way of determining the model parameters from the experiment is described. The comparison of the simulation results with experimental data reveals very good suitability of the model in the case of a starch soil. A similar good agreement is found for data for a model protein foulant in tube flow from the literature.     

Regional science in a resource-constrained world

This paper presents challenges to mainstream regional science that stem from the fact that regional economies are subsumed within larger social, economic and environmental systems. The constraints imposed by these systems are systematically overlooked or misidentified. The challenges that arise for regional science are of conceptual, methodological and empirical nature and have far-reaching implications for the uses and usefulness of regional science analysis in support of investment and policy making. The paper attends to both the challenges and ways they can be overcome.     

Water sorption in poly(vinyl alcohol) membranes: An experimental and numerical study of solvent diffusion in a crosslinked polymer

The development of reliable mathematical models for mass transport in crosslinked polymers and their thorough experimental validation are of substantial interest in the design of technical membrane processes or the assessment of polymer performance when applications such as functional films and protective coatings are concerned.The present study aims at the joint experimental and numerical characterisation of mass transport during water vapour sorption into physically crosslinked poly(vinyl alcohol) membranes. A mathematical model comprising both phase equilibrium and the respective mass transport mechanisms is proposed and verified by means of in situ sorption kinetic measurements. Drawing on the independent determination of equilibrium solvent uptake, the comparison of model calculations and experimental sorption data demonstrates that water transport in the crosslinked polymer membrane is successfully described by pure Fickian diffusion with a simple exponential expression for the solvent diffusion coefficient to account for its pronounced concentration dependency, allowing the latter to be specified quantitatively.     

Recovery and characterisation of coloured phenolic preparations from apple seeds

The aim of this study was to investigate whether complexly constituted phenolic extracts from apple seeds may be utilised for the recovery of natural coloured antioxidant preparations, which might serve as potential food or cosmetic ingredients.In a first step, the recovery of phenolic compounds was optimised by varying crucial extraction parameters. A single extraction step at 25 °C using an acetone–water mixture (60:40, v/v) and a solid-to-solvent ratio of 1:8 (w/v) for 1 h was found to be appropriate to achieve both high phenolic yields and antioxidant activities.In a second step, differently produced apple seed extracts and a phloridzin model solution were enzymatically treated by mushroom polyphenol oxidase to investigate the rate of pigment synthesis. Depending on the extraction procedure applied, synthesis rates, pigment yields and colour properties significantly differed. Compared to the phloridzin model solution, extracts recovered from the seeds showed comparable and even better results, thus indicating such preparations to be a promising alternative to synthetic yellow dyes.     

Klimakonstruktionen

Constructing Climate. From Classical Climatology to Modern Climate Research Both climate researchers and historians of climate science have conceived climate as a stable and well defined category. This article argues that such a conception is flawed. In the course of the 19th and 20th century the very concept of climate changed considerably. Scientists came up with different definitions and concepts of climate, which implied different understandings, interests, and research approaches. Understanding climate shifted from a timeless, spatial concept at the end of the 19th century to a spaceless, temporal concept at the end of the 20th. Climatologists in the 19th and early 20th centuries considered climate as a set of atmospheric characteristics associated with specific places or regions. In this context, while the weather was subject to change, climate remained largely stable. Of particular interest was the impact of climate on human beings and the environment. In modern climate research at the close of the 20th century, the concept of climate lost its temporal stability. Instead, climate change has become a core feature of the understanding of climate and a focus of research interests. Climate has also lost its immediate association with specific geographical places and become global. The interest is now focused on the impact of human beings on climate. The paper attempts to investigate these conceptual shifts and their origins and impacts in order to provide a more comprehensive perspective on the history of climate research.     

Measurement of Helium Leakage Rates through Closures of Dangerous Goods Packagings for the Assessment of Potentially Explosive Mixtures in Freight Containers

The objective was to find out whether an explosive atmosphere can be created in a freight container by gaseous leakage flow of vapour‐air‐mixture through leaks in the closures of dangerous goods packagings filled with hazardous liquids. Because of high temperatures during intercontinental carriage, there is a gauge pressure in the free vapour phase inside the packagings which can cause a gaseous leakage flow. Two different methods were applied: Helium limit leakage rates for 23 quantitatively important hazardous liquids concerning their lower explosion limit (LEL) were calculated for a worst case transport scenario (Method 1). Helium leakage rates of five closure types of dangerous goods packagings with volumes of approximately 6 l were measured using the pressure technique by accumulation (Method 2). All types of closures of steel packagings were uncritical. The maximum measured leakage was 33% of the limit leakage rate. The leakage rates of screw closures of plastic jerricans can exceed the LEL if there are production‐related patterns such as non‐concentricity of the closures and flashes on the neck. Especially for plastic packagings it is important to minimize gaseous leakage flow, because an explosive atmosphere can also be reached by permeation of the individual filling substance or by a combination of both effects. For the assessment of potentially explosive mixtures in freight containers, both mass transfer mechanisms have to be taken into account. Copyright © 2015 John Wiley & Sons, Ltd.     

Gramazio Kohler Research,Automated Diversity: New Morphologies of Vertical Urbanism

Automated fabrication techniques are currently largely confined to the production of discrete objects or building elements. To notch up the potential of robotics for architectural design, it is necessary to start to push the limits and experiment at a larger urban scale. Fabio Gramazio and Matthias Kohler are pioneers in this field. Here, with Jan Willmann , they describe the research that they are undertaking as part of the Future Cities Laboratory (FCL) located at the Singapore-ETH Centre for Global Environmental Sustainability (SEC) and ETH Zurich, in which robotic fabrication technologies are employed to realize 1:50 physical models of mixed-use high-rise structures that are unique in their spatial layouts.