Phase behavior,density, and crystallization of polyethylene in n‐pentane and in n‐pentane/CO2 at high pressures

The phase behavior and volumetric properties of polyethylene (PE) in solutions of n‐pentane and n‐pentane/CO₂ were studied in a temperature (T) range of 370–440 K at pressures up to 60 MPa. Measurements were conducted with a variable‐volume view‐cell system equipped with optical sensors to monitor the changes in the transmitted light intensity as the P or the T of the system was changed. Lower‐critical‐solution‐temperature‐type behavior was observed for all of the liquid–liquid (L–L) phase boundaries, which shifted to higher pressures in solutions containing CO₂. The solid–fluid (S–F) phase boundaries were investigated over a P range of 8–54 MPa and took place in a narrow T range, from 374 to 378 K in this P interval. The S–F phase boundary showed a unique feature in that the demixing temperatures showed both increasing and decreasing trends with P depending on the P range. This was observed in both the PE/n‐pentane and PE/n‐pentane/CO₂ mixtures. The density of these solutions were measured as a function of P at selected temperatures or as a function of T at selected pressures that corresponded to the paths followed in approaching the phase boundaries (S–F or L–L) starting from a homogeneous one‐phase condition. The data showed a smooth variation of the overall mixture density along these paths. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2201–2209, 2003     

Event Processing Support for Cross-Reality Environments

Complex event processing (CEP) is an essential functionality for cross-reality environments. Through CEP, we can turn raw sensor data generated in the real world into more meaningful information that has some significance for the virtual world. In this article, the authors present DejaVu, a general-purpose event processing system built at ETH Zurich. SmartRFLib, a cross-reality application, builds on DejaVu and enables real-time event detection over RFID data streams feeding a virtual library on second life.     

An interdisciplinary heuristic evaluation method for universal building design

This study highlights how heuristic evaluation as a usability evaluation method can feed into current building design practice to conform to universal design principles. It provides a definition of universal usability that is applicable to an architectural design context. It takes the seven universal design principles as a set of heuristics and applies an iterative sequence of heuristic evaluation in a shopping mall, aiming to achieve a cost-effective evaluation process. The evaluation was composed of three consecutive sessions. First, five evaluators from different professions were interviewed regarding the construction drawings in terms of universal design principles. Then, each evaluator was asked to perform the predefined task scenarios. In subsequent interviews, the evaluators were asked to re-analyze the construction drawings. The results showed that heuristic evaluation could successfully integrate universal usability into current building design practice in two ways: (i) it promoted an iterative evaluation process combined with multi-sessions rather than relying on one evaluator and on one evaluation session to find the maximum number of usability problems, and (ii) it highlighted the necessity of an interdisciplinary ad hoc committee regarding the heuristic abilities of each profession. A multi-session and interdisciplinary heuristic evaluation method can save both the project budget and the required time, while ensuring a reduced error rate for the universal usage of the built environments.     

Prioritization methodology of dangerous substances for water quality monitoring with scarce data

Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries).     

Turkish validation of the Game Transfer Phenomena Scale (GTPS): Measuring altered perceptions,automatic mental processes and actions and behaviours associated with playing video games

Studies on Game Transfer Phenomena (GTP) have demonstrated that experiencing altered sensorial perceptions, automatic thoughts and behaviours after playing video games are relatively common phenomena. The aim of this paper is twofold: (i) to validate the Turkish version of the GTP scale (GTPS), and (ii) to examine the prevalence and the relation between the various dimensions of GTP (e.g., visual perceptions, thoughts, behaviours) and video game players’ individual characteristics (e.g., demographics, gaming habits). A total of 954 frequent players were recruited online. Independently of the different samples used in the original validation of the GTPS and the current study, the findings obtained via confirmatory factor analysis showed that the GTPS-Turkish is reliable and valid and proved to be adequate for measuring GTP. A total of 99% of the players in the sample had experienced some type of GTP. Moreover, the correlational, univariate and multivariate analyses showed associations between various video game player characteristics and GTP. The most remarkable finding was that the prevalence of GTP was higher among minors than adults.     

Synthesis,characterization and thermal behaviors of polymers containing organosilicon groups

Various bis(silyl)ethenyl groups were attached to the aromatic ring of poly(α-methylstyrene) via Peterson olefination reaction of (RMe₂Si)₃CLi (R = H, Me and Ph) with formylated poly(α-methylstyrene) (Pα-MS-CHO) to give poly(α-methylstyrene)-co-[2,2-bis(silyl)ethenyl(α-methylstyrene)] as functionalized poly(α-methylstyrene) (Pα-MS-SiMe₂H, Pα-MS-SiMe₃ and Pα-MS-SiMe₂Ph). The trimethylsilyl groups of Pα-MS-SiMe₃ have been converted to 2,2-dibromoethenyl and epoxybis(silanes) groups via NBS-based bromodesilylation and MCPBA-based epoxidation respectively. The thermal degradation behaviors of the polymers were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).     

Effect of a sulfonated azo dye and sulfanilic acid on nitrogen transformation processes in soil

Introduction of organic dyes into soil via wastewater and sludge applications has been of increasing concern especially in developing or under-developed countries where appropriate management strategies are scarce. Assessing the response of terrestrial ecosystems to organic dyes and estimating the inhibition concentrations will probably contribute to soil remediation studies in regions affected by the same problem. Hence, an incubation study was conducted in order to investigate the impact of a sulfonated azo dye, Reactive Black 5 (RB5) and sulfanilic acid (SA), a typical representative of aromatic sulfonated amines, on soil nitrogen transformation processes. The results apparently showed that nitrogen related processes in soil can be used as bioindicators of anthropogenic stress caused by organic dyes. It was found that urease activity, arginine ammonification rate, nitrification potential and ammonium oxidising bacteria numbers decreased by 10–20% and 7–28% in the presence of RB5 (>20 mg/kg dry soil) and SA (>8 mg/kg dry soil), respectively. Accordingly, it was concluded that organic dye pollution may restrict the nitrogen-use-efficiency of plants, thus further reducing the productivity of terrestrial ecosystems. Furthermore, the response of soil microbiota to SA suggested that inhibition effects of the organic dye may continue after the possible reduction of the parent dye to associated aromatic amines.     

Gold recovery from dilute gold solutions using DEAE-cellulose

The present work investigates gold recovery using DEAE-cellulose, a common biopolymer derivative, from synthetically prepared diluted gold-bearing solutions of 50 ppm. The effects of different recovery parameters on gold recovery efficiency were studied in detail. It was demonstrated that gold recovery efficiency increased with an increasing amount of sorbent, as well as increasing contact time. A gold recovery efficiency of 99% was attained under conditions of 20–40 g DEAE-cellulose per liter at a shaking rate of 130 rpm for 30 min at room temperature. On the other hand, with smaller amounts of sorbent (6 g/l), it was also possible to recover gold from the solution with 99% efficiency when the reaction temperature was increased to 60 °C. The shaking rate and temperature were demonstrated to play a vital role in the recovery process. It was also found that gold recovery by DEAE-cellulose is an intermediate-controlled process with an activation energy of 37.11 kJ/mol. The XRD pattern and SEM images revealed that the recovered gold was in the metallic form.     

Capacity factor prediction and planning in the wind power generation industry

The common practice to calculate wind generation capacity values relies more on heuristic approximations than true system estimations. In this paper we proposed a more accurate method. In the first part of our analysis, a Monte Carlo simulation was created based on Markov chains to provide an independent estimate of the true behavior of wind farm capacity value as a function of system penetration. With this curve as a baseline, a technique for using beta distributions to model the input variables was adopted. A final step to increase accuracy involved the use of numerical convolution within the program to eliminate summation estimates.