A study of ergonomics factors in washbasin design

A 4-week UNESCO-sponsored mission to the Department of Architecture, Karadeniz Technical University in Eastern Turkey, gave an opportunity to apply ergonomics techniques to some aspects of that country's domestic washbasin design. The study was intended to provide experience in questionnaire design and administration, in the application of psycho-physical methods, and to highlight the importance of determining user characteristics and preferences with regard to the built environment. A field study elicited information on dimensions and positioning of existing wash-basins and ancillary equipment and the opinions of users as to the suitability of these features in relation to the activities performed. A laboratory study, using an adjustable rig permitting variation in the heights of basin, taps and mirror/shelf, followed. The data obtained on preferred heights of these items led to the conclusions that basin height should be increased to between 95 and 100 cm to satisfy the majority of users; tap height above the basin should be reduced to about 11 cm; the shelf and lower edge of a mirror sited above the basin should be 136 cm above the floor; and a clear space of 110 cm should be available between the front of the basin and a wall or other obstruction. Suggestions on other design aspects of the bathroom, resulting from the study, are discussed.     

Microanalytical investigation of sintered SiC

UHV-fracture surfaces of different (B, C)- and (Al, C)-doped pressureless sintered SiC materials are investigated by using high resolution Auger electron spectroscopy (HRAES). The grain boundaries at intergranular fractured regions of (B, C)-doped materials are evidently free of any enrichment of impurity elements or sintering additives. In contrast, the (Al, C)-doped materials reveal the existence of thin Al-containing grain boundary films. Sputtering indicates their thickness to be less than 1 nm. The concentrations of the elements segregated in the grain boundary films are determined.     

GENOTOXICITY IN CHIRONOMUS KIIENSIS (CHIRONOMIDAE: DIPTERA) AFTER EXPOSURE TO POLLUTED SEDIMENTS FROM RIVERS OF NORTH PENINSULAR MALAYSIA: IMPLICATION FOR ECOTOXICOLOGICAL MONITORING

Rapid industrialization and urbanization has led to increasing input of chemical contaminants into the aquatic environment of Malaysia. Despite the threat civilization poses to the biota, there are still very few relevant studies on ecotoxicological testing of river ecosystems. To overcome this knowledge gap, we examined lethal and genotoxic effects of sediments from different rivers of the northern Malaysia against Chironomus kiiensis, a group well represented in the aquatic fauna of this region. We exposed the larvae to sediments from Selama River (SR), Permatang Rawa River (PRR) and Kilang Ubi River (KUR) at various durations (0, 6, 12, 24 and 48 h). The larval mortality was monitored, whereas DNA damage in survivors' cells was determined using the comet assay. Pollution level indexed by the amounts of heavy metals and other organic contaminants in the sediment showed progressive increases from SR to PRR to KUR. Highly polluted sediments (PRR to KUR) were detrimental to C. kiiensis larvae, most of which did not survive following exposure for long periods. DNA analyses revealed greater damages in nuclei derived from larvae maintained on polluted sediments, in particular, those from KUR. The effects on the genomic material of C. kiiensis larvae occurred in a time‐dependent manner, with damage level increasing as exposure time progressed. Our results highlight the genotoxic properties of polluted sediments. More importantly, this study showed that C. kiiensis larvae could respond to different levels of pollution with respect to exposure time. It is concluded that C. kiiensis larvae is a potential candidate for river ecotoxicological monitoring. Copyright © 2012 John Wiley & Sons, Ltd.     

Stakeholder orientated sustainable land management: The Ruhr Area as a role model for urban areas

The concept of sustainable land management (SLM) can help create a balance between the different demands of economy, society and nature. SLM means to actively develop land based on a knowledge-based procedure. It should aim on long term enhancements. The basis of SLM is the interests and the goals of the stakeholders. It is the result of a bargaining process between different institutions by creating win-win-situations or adequate conflict solutions to reach a consensus. The Ruhr Area is Germany’s biggest metropolitan area. Land management regarding economic, social and environmental issues, which has a long tradition in this area, goes back to 1920. Being the centre of the heavy industry in Germany for more than 150 years, the Ruhr Area today is a green metropolis. The ecological, social and economical change of this industrial region can serve as a role model for SLM in urban areas all over the world.     

Removal of bacteriophages with different surface charges by diverse ceramic membrane materials in pilot spiking tests

This study examines mechanisms for removal of bacteriophages (MS2 and phiX174) by ceramic membranes without application of flocculants. The ceramic membranes considered included ultra- and microfiltration membranes of different materials. Phages were spiked into the feed water in pilot scale tests in a waterworks. The membranes with pore sizes of 10 nm provided a 2.5-4.0 log removal of the phages. For pore sizes of 50 nm, the log removal dropped to 0.96-1.8. The membrane with a pore size of 200 nm did not remove phages. So, the removal of both MS2- and phiX174-phages depended on the pore size of the membranes. But apart from pore size also other factors influence the removal of phages. Removal was 0.5-0.9 log higher for MS2-phages compared with phiX174-phages. Size exclusion seems to be the major but not the only mechanism which influences the efficiency of phage removal by ceramic membranes.     

Use of sesame stalk biomass for the removal of Ni(II) and Zn(II) from aqueous solutions

In this study an agricultural residue, sesame stalk, was evaluated for the removal of Ni(II) and Zn(II) metal ions from aqueous solutions. Biosorption studies were carried out at different pH, biosorbent dosage, initial metal ion concentrations, contact time, and solution temperature to determine the optimum conditions. The experimental data were modeled by Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Langmuir model resulted in the best fit of the biosorption data. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data and to evaluate rate constants. The best correlation was provided by the second-order kinetic model. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The experimental results showed that sesame stalk can be used as an effective and low-cost biosorbent precursor for the removal of heavy metal ions from aqueous solutions.     

Evaluation of Crop Models for Simulating and Optimizing Deficit Irrigation Systems in Arid and Semi-arid Countries Under Climate Variability

The variability of fresh water availability in arid and semi-arid countries poses a serious challenge to farmers to cope with when depending on irrigation for crop growing. This has shifted the focus onto improving irrigation management and water productivity (WP) through controlled deficit irrigation (DI). DI can be conceived as a strategy to deal with these challenges but more knowledge on risks and chances of this strategy is urgently needed. The availability of simulation models that can reliably predict crop yield under the influence of soil, atmosphere, irrigation, and agricultural management practices is a prerequisite for deriving reliable and effective deficit irrigation strategies. In this context, this article discusses the performance of the crop models CropWat, PILOTE, Daisy, and APSIM when being part of a stochastic simulation-based approach to improve WP by focusing primarily on the impact of climate variability. The stochastic framework consists of: (i) a weather generator for simulating regional impacts of climate variability; (ii) a tailor-made evolutionary optimization algorithm for optimal irrigation scheduling with limited water supply; and (iii) the above mentioned models for simulating water transport and crop growth in a sound manner. The results present stochastic crop water production functions (SCWPFs) that can be used as basic tools for assessing the impact on the risk for the potential yield due to water stress and climate variability. Example simulations from India, Malawi, France and Oman are presented and the suitability of these crop models to be employed in a framework for optimizing WP is evaluated.     

Novel combination of orientation measurements and transmission microscopy for experimental determination of grain boundary miller indices in silicon and other semiconductors

The determination of grain boundary planes in multicrystalline material has only been restricted to transmission electron microscope investigations (Jang et al., 1992; Elgat et al., 1985) or to metallograpical investigations of the grain boundary (Randle et al., 1993). The first method is expensive, and both are complex and time consuming in grain boundary preparation. This paper proposes the determination of grain boundary planes in semiconductor wafer by a combined application of Electron Back Scatter Diffraction and Infrared Transmission Microscopy. In particular, the new method is demonstrated with directional solidificated multicrystalline silicon.     

Compact cryogenic source of periodic hydrogen and argon droplet beams for relativistic laser-plasma generation

We present a cryogenic source of periodic streams of micrometer-sized hydrogen and argon droplets as ideal mass-limited target systems for fundamental intense laser-driven plasma applications. The highly compact design combined with a high temporal and spatial droplet stability makes our injector ideally suited for experiments using state-of-the-art high-power lasers in which a precise synchronization between the laser pulses and the droplets is mandatory. We show this by irradiating argon droplets with multi-terawatt pulses.