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.     

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.     

Scalable parallel implementation of migrating birds optimization for the multi-objective task allocation problem

The Journal of Supercomputing - As the distributed computing systems have been widely used in many research and industrial areas, the problem of allocating tasks to available processors in the...     

A facile synthesis of polyaniline/polyethylene glycol/polyaniline terpolymers: preparation of electrospun conducting nanofibers by blending of the terpolymers with polycaprolactone

The water-soluble terpolymers were synthesized in two steps, containing esterification of polyethylene glycol (PEG) and 4-amino benzoic acid without protection of its amino group, then copolymerization of aniline from both end of amine-terminated PEG via an interfacial polymerization method. The chemical structure of triblock copolymers was determined by FTIR and ¹HNMR. The thermal behavior, morphology and electroactivity of terpolymers were also investigated by thermogravimetric analysis, field emission microscope (FESEM) and cyclic voltammetry (CV), respectively. Uniform nanofibers consisting of blends of (PANI)_n-b-PEG-b-(PANI)_n terpolymers and polycaprolactone (PCL) were prepared using electrospinning technique. The FESEM was also used to investigate the electrospun nanofibers produced from different molecular weight of PANI/PEG/PANI terpolymers and PCL (30/70). The CV measurements of blends confirmed the preparation of electroactive nanofibers. The presence of terpolymers enhanced the spinnability of solution and significantly reduced the bead formation. This novel system opens up new and interesting opportunities for applications such as electroactive scaffold for tissue engineering.     

Polymer solar cells with NiO hole-collecting interlayers processed by atomic layer deposition

We report on the photovoltaic properties of polymer solar cells that use NiO-coated indium tin oxide (ITO) as the hole-collecting electrode. The NiO films were prepared by atomic layer deposition (ALD) on top of ITO with thicknesses varying from 6 to 25 nm. The NiO films increase the work function (WF) of the ITO, allowing NiO-coated ITO to act as an efficient hole-collecting electrode. Devices made with pristine NiO showed poor current–voltage characteristics. However, subsequent O₂-plasma treatment further increased the WF of NiO, tuning NiO-coated ITO into an efficient hole-collecting electrode for polymer solar cells based on the donor poly(3-hexylthiophene-2,5-diyl) (P3HT). The polymer solar cells with the O₂-plasma treated NiO-coated ITO hole-collecting electrodes yield a power conversion efficiency of 4.1 ± 0.2% under simulated air mass 1.5 G 100 mW/cm² illumination, which is comparable to reference devices with poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)-coated ITO hole-collecting electrodes.     

Comparing technology acceptance of K-12 teachers with and without prior experience of learning management systems: A Covid-19 pandemic study

Covid-19 pandemic has caused a massive transformation in K-12 settings towards online education. It is important to explore the factors that facilitate online teaching technology adoption of teachers during the pandemic. The aim of this study was to compare Learning Management System (LMS) acceptance of Finnish K-12 teachers who have been using a specific LMS as part of their regular teaching before the Covid-19 pandemic (experienced group) and teachers who started using it for emergency remote teaching during the pandemic (inexperienced group). Based on the Unified Theory of Acceptance and Use of Technology framework, a self-report questionnaire was administered to 196 teachers (n_experienced = 127; n_{inexperienced} = 69). Our findings showed no difference between the two groups of teachers in terms of performance expectancy, effort expectancy, LMS self-efficacy and satisfaction. However, the experienced group had higher behavioural intention to use LMS in the future, reported receiving higher online teaching support and displayed higher online teaching self-efficacy in terms of student engagement, classroom management, instructional strategies and ICT skills. For the experienced group, the most significant predictor of satisfaction with LMS was performance expectancy whereas for the inexperienced group, it was the effort expectancy. In terms of behavioural intention to use LMS in the future, the most significant predictor was the performance expectancy for both groups. Further, support was also a significant predictor of behavioural intention for the inexperienced group. Overall, our findings indicate that teachers should not be regarded as a unified profile when managing technology adoption in schools.