COD and AOX Removal and Biodegradability Assessment for Fenton and O3/UV Oxidation Processes: A Case Study from a Graphical Industry Wastewater

Due to process stability and excellent effluent quality, the use of membrane processes is rapidly expanding. However, a drawback is the production of concentrates and their proper disposal. In this study, reverse osmosis concentrate was treated by Fenton and O₃/UV oxidation processes. The concentrate contains halogenated compounds, recalcitrant COD and low biodegradability. The removal of halogenated compounds and the enhancement of biodegradability were examined. Comparing the investigated processes, Fenton oxidation resulted in a better mineralization of organic matter; however, O₃/UV oxidation achieved a better enhancement of the biodegradability. Furthermore, similar degradation of halogenated compounds were observed for both oxidation processes.     

External Support of Problem Analysis in Design Problem Solving

Design is described as creative design problem solving. The first step of the design process is to identify and analyze the design problem. This step has an important influence on the creation of an effective design solution. In two experiments, we tested the benefits that sketching provides during the analysis process in design problem solving. In particular, this paper focuses on the design process, the act of sketching, the sketch itself, and the final product. In prior studies, the process of sketching has been shown to enhance the construction of a mental representation, and thus the sketch has improved the analysis of the problem. The memory supporting effect of sketches is verified in the second experiment discussed in this paper. Finally, this paper also discusses the support possibilities the sketch offers for the early stages of the design process.     

Do as your parents say?—Analyzing IT adoption influencing factors for full and under age applicants

The article suggests a model for examining the adoption of e-recruiting by individuals. The model is empirically evaluated using survey data from 323 full and under age applicants. The results explain substantial parts of the individual adoption decision. Interestingly, the relative importance of the adoption drivers varies with age, social environment and the level of education. While, as expected, overall Performance Expectancy is the major force behind adopting e-recruiting, the relative importance of the other factors differs a lot. Whereas Facilitating Conditions came out as an important driver for under age pupils, full age students by contrast are highly driven by the influence of their peer groups and the communication of the respective company they apply for. A major outcome is that the Subjective Norm of family and friends, teachers and professors has a weaker influence for under age pupils who mostly live with their parents than for the group of students who already left home to study at college. Consequentially we assume that the social influence of peer groups on an individual’s adoption differs with respect to age, social environment and level of education. This should be investigated more carefully in future adoption research as it might provide an answer for the varying significance of Subjective Norm in adoption research.     

Minimum cost flows with minimum quantities

We consider a variant of the well-known minimum cost flow problem where the flow on each arc in the network is restricted to be either zero or above a given lower bound. The problem was recently shown to be weakly NP-complete even on series-parallel graphs. We start by showing that the problem is strongly NP-complete and cannot be approximated in polynomial time (unless P=NP) up to any polynomially computable function even when the graph is bipartite and the given instance is guaranteed to admit a feasible solution. Moreover, we present a pseudo-polynomial-time exact algorithm and a fully polynomial-time approximation scheme (FPTAS) for the problem on series-parallel graphs.     

Obstacles for cognitive analogy in analysis and synthesis in microsystems development

In most cases, product development is not inventing a product completely new and from scratch, it typically either adds a few newly developed sub-functions to mainly known sub-functions, or it generates invention based on new combinations of already existing and slightly modified sub-functions. This synthesis is ideally based on a preceding and comprehensive system analysis that is necessary to define promising directions for advancement in further product development. In analysis as well as in synthesis the design engineer needs creativity—either to be able to recognize which functions are realized in a given system that is subject to analysis or to be able to think up new ways how a desired function could be realized in a system. The main cognitive mechanism for creativity is analogy and this mechanism in turn is based on schemas and mental models. In microsystems development, micro specific obstacles accrue when using analogies. In this work, the authors derive the nature and source of these obstacles and their implications on microsystems development. To overcome these obstacles, a functions catalogue is proposed. This catalogue can directly be used to add an external source for analogies during system synthesis. By transferring a method called geometrical similarity search to microsystems technology and combining it with the functions catalogue, system analysis can be supported as well.     

Influence of Stress and Chemical Homogeneity on Dielectric Properties of BaTi0.9Zr0.1O3

The influence of mechanical stress and chemical homogeneity on the permittivity of BaTi_0.9Zr_0.1O₃ ceramics prepared from mixed-oxide and hydrothermal powders was studied. To reduce stress, liquid-phase sintering was applied in conjunction with a low heating rate to stimulate the formation of large grains. The influence of chemical homogeneity was studied by variations in sintering temperatures and times. For both types of ceramics, the dielectric constant at the Curie temperature was influenced by both factors, but to a different extent. In the mixed oxide ceramic, chemical homogeneity played a more prominent role, while internal stress appeared to exert a larger influence in the hydrothermal ceramics. The dielectric constant at the Curie temperature could be increased by 5%–10% by an annealing treatment at 200°C, followed by slow cooling.     

Energy efficiency and renewable energy under extreme conditions: Case studies from Antarctica

This article showcases a range of small and large scale energy efficiency and renewable energy deployments at Antarctic research stations and field camps. Due to the cold and harsh environment, significant amounts of fuel are needed to support humans working and living in Antarctica. The purchase, transportation and storage of large amounts of fossil fuel entail significant economic costs and environmental risks and have motivated developments in energy efficiency and renewable energy deployment. Over the past three decades, improved building design, behavioral change, cogeneration, solar collectors, solar panels and wind turbines have been found to be effective in Antarctica, demonstrating that harsh environmental conditions and technological barriers do not have to limit the deployment of energy efficiency and renewable energy. The ambition to run entire stations or field camps on 100% renewable energy is increasingly common and feasible. While the power requirements of Antarctic research stations are small compared to urban installations on other continents, these case studies clearly demonstrate that if energy efficiency and renewable energy can be deployed widely on the coldest, darkest and most remote continent of the world, their deployment should be more widespread and encouraged on other continents.