Competitive removal of Pb2+, Cd2+, and Zn2+ by poly(acrylamide‐co‐maleic acid) hydrogels/differential pulse polarographic determination

Poly(acrylamide‐co‐maleic acid) [P(AAm/MA)] hydrogels, with various compositions, were prepared from ternary mixtures of acrylamide (AAm)/maleic acid (MA)/water by using ⁶⁰Co γ‐rays. The effect of composition of these hydrogels, on the competitive removal of Pb²⁺, Cd²⁺, and Zn²⁺ ions from aqueous solution, was investigated. The hydrogel compositions and their adsorption behaviors were determined by use of differential pulse polarography, a very sensitive electroanalytical technique. It was observed that the external stimuli of pH, temperature, and ionic strength have an important role on the adsorption. The increments of MA content in P(AAm/MA) hydrogels caused a significant increase in the adsorption these ions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2401–2406, 2004     

Magnetoresistance behaviour in CoFe/Cu multilayers: thin Cu layer effect

The magnetoresistance properties of the CoFe/Cu multilayers have been investigated as a function of thin non-magnetic Cu layer thickness (from 2.5 to 0.3 nm). CoFe/Cu multilayers were electrodeposited on Ti substrates from a single electrolyte containing their metal ions under potentiostatic control. The structural analysis of the films was made using X-ray diffraction. The peaks appeared at 2θ ≈ 44°, 51°, 74° and 90° are the main Bragg peaks of the multilayers, arising from the (111), (200), (220) and (311) planes of the face-centered cubic structure, respectively. The magnetic characterization was performed by using vibration sample magnetometer in magnetic fields up to ±1600 kA/m. At 0.6, 1.2 and 2.0 nm Cu layer thicknesses, the high saturation magnetization values were observed due to antiferromagnetic coupling of adjacent magnetic layers. Magnetoresistance measurements were carried out using the Van der Pauw method in magnetic fields up to ±1000 kA/m at room temperature. All multilayers exhibited giant magnetoresistance (GMR), and the similar trend in GMR values and GMR field sensitivity was observed depending on the Cu layer thickness.     

Behavior change through wearables: the interplay between self-leadership and IT-based leadership

Electronic Markets - Physical inactivity is a global public health problem that poses health risks to individuals and imposes financial burdens on already strained healthcare systems. Wearables...     

Incidence and antibiotic resistance of Salmonella spp. on raw chicken carcasses

The current study was carried out to detect Salmonella spp. contamination on chicken carcasses and to determine the antibiotic susceptibility profiles and serotype distribution of the isolates. A total of 200 packaged fresh raw chicken samples sold at retail in different markets in central Anatolia were analysed between April 2005 and March 2006. Salmonella spp. was detected in 34% (68/200) of samples using cultural technique and were confirmed by PCR. Ten Salmonella serovars were identified; predominant ones included Typhimurium, Infantis and Heidelberg. All of the Salmonella spp. isolates tested, exhibited resistance to one or more antimicrobial agents used. Resistance to penicillin, oxacillin, clindamycin, vancomycin, erythromycin and ampicillin were evident 100%, 97%, 97%, 92.6%, 89.7% and 85.2%, respectively. Also resistance to tetracycline (67.6%), streptomycin (61.7%), neomycin (55.8%) and cephalothin (52.9%) was observed but a small percentage of the isolates demonstrated resistance to gentamicin (14.7%), chloramphenicol (10.2%), cefotaxime (2.9%) and amikacin (2.9%). As a result, high prevalence of Salmonella spp. and the relatively high resistance among the bacteria tested could pose public health and therapeutic problems in consumers as potential vehicle of resistant Salmonella foodborne infections. To avoid Salmonella contamination, hygienic rules of slaughter and poultry meat processing must be rigorously observed and antibiotic use must be controlled by governmental agencies to prevent increased resistance of antibiotics.     

Web accessibility guideline aggregation for older users and its validation

Web site-evaluation methodologies and validation engines take the view that all accessibility guidelines must be met to gain compliance. Problems exist in this regard, as contradictions within the rule set may arise, and the type of impairment or its severity is not isolated. The Barrier Walkthrough (BW) method goes someway to addressing these issues, by enabling barrier types derived from guidelines to be applied to different user categories such as motor or visual impairment, etc. However, the problem remains of combinatorial explosion of possibilities when one has to consider users with multiple disabilities. In this paper, a simple set theory operation is used to create a validation scheme for older users by aggregating barrier types specific to motor impaired and low-vision users, thereby creating a new “older users” category from the results of this set union. To evaluate the feasibility and validity of this aggregation approach, two BW experiments were conducted. The first experiment evaluated the aggregated results by focusing on quality attributes and showed that aggregation generates data whose quality is comparable to the original one. However, this first experiment could not test for validity, as the older users category was not included. To remedy this deficiency, another BW experiment was conducted with expert judges who evaluated a web page in the context of older users. In this second experiment, it was found that there is no significant difference between the aggregated and the manually evaluated (by experts) barrier scores, and that the same barriers are identified using experts and aggregation, even though there are differences in how severity scores are distributed. From these results, it is concluded that the aggregation of barriers is a viable alternative to expert evaluation, when the target of that aggregation could not be evaluated manually or it would not be feasible to do so. It is also argued that aggregation is a technique that can be used in combination with other evaluation methods, like user testing or subjective assessments.     

Robust microencapsulated phase change materials in concrete mixes for sustainable buildings

For passive building applications, phase change materials (PCMs) are microencapsulated to avoid leakage of PCM from concrete structure. The primary challenge of using microencapsulated PCM (MPCM) is its weak shell structure. New MPCMs with different shell compositions to prevent breakage during mixing in fresh concrete are needed. In this study, free radical polymerization method to microencapsulate capric acid–myristic acid mixture as PCM with two different methyl methacrylate co‐polymers is proposed to produce robust MPCMs for building applications. Two new microcapsules (MPCM‐1 and MPCM‐2) having latent heats of 91.9 and 97.3 J/g were synthesized. SEM analyses showed the size of microcapsules being in the range of 400–850 nm for MPCM‐1 and 250–475 nm for MPCM‐2. Analyses also reveal that the shells of MPCMs were not harmed, as they were added into concrete mixes. The microsphere's geometry was preserved, and distribution was homogeneous. The MPCMs were also studied under thermal tests of 1000 heating/cooling cycles. No significant changes in thermal properties were observed after thermal cycling tests. Copyright © 2016 John Wiley & Sons, Ltd.     

Web Authoring for Accessibility (WAfA)

Conventional thought from the Semantic Web community equates the use of ontologies with the representation of the meaning of content. Here, we skew this viewpoint by describing our ontology, Web Authoring for Accessibility (WAfA), which investigates the way ontologies can describe the semantic structure of documents. By understanding the way heterogeneous XHTML (Extensible Hypertext Mark-up Language) documents are structured we can better transform documents, currently inaccessible to visually impaired users. WAfA performs two tasks: (1) it allows us to flexibly model an XHTML document within the context of navigation and orientation through the Web resource; (2) it enables non-expert users to quickly annotate a Web document by providing a ‘lingua franca’ between author and Web Accessibility Domain Experts. Here we describe our ontology, its use, novelty, and importance.     

Production of nano zinc borate (4ZnO·B2O3·H2O) and its effect on PVC

In this study, nano sized zinc borate powder with a formula of 4ZnO·B₂O₃·H₂O was synthesized using 2ZnO·3B₂O₃·3.0–3.5H₂O as a starting chemical which was produced using a wet chemical method. After dissolving 2ZnO·3B₂O₃·3.0–3.5H₂O in an ammonia solution, the clear solution was boiled until a white powder formed. The resultant powder was characterized with XRD, FTIR, TGA and TEM. XRD, FTIR and TGA results proved that the powder was belonged to the 4ZnO·B₂O₃·H₂O. Nano composites of 4ZnO·B₂O₃·H₂O–polyvinylchloride (PVC) were produced by injection moulding by adding 1 and 5 wt% zinc borate powders into PVC to enhance its flame retardancy. Limiting oxygen index (LOI) of virgin PVC increased from 41% to 47% and 54% for the 1 and 5 wt% zinc borate added PVC, respectively. Nano zinc borate addition into the PVC does not have considerable negative effect on the mechanical properties of zinc borate–PVC composites even at high amounts of 5 wt%.     

Thermal buffering effect of a packaging design with microencapsulated phase change material

Temperature fluctuations during storage and transportation are the most important factors affecting quality and shelf life of food products. Phase change materials (PCM) with their isothermal characteristics are used to control temperature in various thermal operations. In this study, octanoic acid as PCM candidate was used in a packaging material design for thermal control of a food product. The PCM candidate was microencapsulated in different shell materials in our laboratory. Among the synthesized microcapsules, microencapsulated PCM (mPCM) (ΔHm = 42.9 J/g) with styrene polymer as the shell material was selected based on its properties of being cost effective and compatibility with human health. Thermal buffering effect of PCM in bulk and microencapsulated forms was tested in a packaging design with special PCM pockets. Results showed that packages with mPCM and bulk PCM provided 8.8 and 6 hours of thermal buffering effect for 160 g of chocolate compared with the package without PCM (reference package).