Removal of basic dyes from aqueous solutions by crosslinked‐acrylic acid/acrylamidopropane sulfonic acid hydrogels

In this study, Acrylic acid (AA)/2‐acrylamido‐2‐methlypropane sulfonic acid (AMPS) hydrogels were prepared by free radical polymerization in aqueous solutions of AA, AMPS, and N,N‐methylenebisacrylamide (NMBA) as crosslinker. Potassium persulfate (PPS)/potassium bisulfide (PBS) were used as initiator and accelerator pair. The water absorption capacities and dye adsorption properties of the hydrogels were investigated. Adsorption properties of the hydrogels were evaluated by depending on different adsorption conditions such as different initial dye concentration and contact time. The concentrations of the dyes were determined using UV/Vis Spectrophotometer at wavelength 530 nm for safranine T (ST) and 622 nm for brilliant cresyl blue (BCB). Adsorption kinetic studies showed that pseudo‐first order kinetic model is suitable to explain the adsorption kinetic data of the hydrogels. Langmuir and Freundlich isotherm models were used to describe adsorption data. The result revealed that the adsorption of basic dyes onto hydrogels fit very well both Langmuir and Freundlich isotherms. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Minimum-energy broadcast and multicast in wireless networks: An integer programming approach and improved heuristic algorithms

Both integer programming models and heuristic algorithms have been proposed for finding minimum-energy broadcast and multicast trees in wireless ad hoc networks. Among heuristic algorithms, the broadcast/multicast incremental power (BIP/MIP) algorithm is most known. The theoretical performance of BIP/MIP has been quantified in several studies. To assess the empirical performance of BIP/MIP and other heuristic algorithms, it is necessary to compute an optimal tree or a very good lower bound of the optimum. In this paper, we present an integer programming approach as well as improved heuristic algorithms. Our integer programming approach comprises a novel integer model and a relaxation scheme. Unlike previously proposed models, the continuous relaxation of our model leads to a very sharp lower bound of the optimum. Our relaxation scheme allows for performance evaluation of heuristics without having to compute optimal trees. Our contributions to heuristic algorithms consist of the power-improving algorithm successive power adjustment (SPA), and improved time complexity of some previously suggested algorithms. We report extensive numerical experiments. Algorithm SPA finds better solutions in comparison to a host of other algorithms. Moreover, the integer programming approach shows that trees found by algorithm SPA are optimal or near-optimal.     

Post-buckling behavior of carbon fiber epoxy composite plates

In this study, the pre-buckling and post-buckling behaviors of layered composite plates which were made of woven carbon fiber fabric with a circular hole in the middle were investigated experimentally and numerically. Firstly, load-displacement graphs of composite plates with different hole diameters were experimentally obtained under compressive load. Then the numerical load-displacement graphs of the plates were found with the ANSYS package program which used the finite element method. As a result, after linear buckling experimental and numerical results were found to be compatible with each other. In addition, damage behavior of plates after buckling with the aid of Tsai-Wu damage criterion was obtained similar to experimental results. The increase in hole diameter did not change the load-displacement behavior characteristics of the plates after buckling. However, it has reduced maximum damage load and maximum failure displacement. The stress at the perimeter of the hole increased significantly with the increase of the vertical displacement with immediately after the buckling but later was not significantly affected by this increase.

     

Three-parameter (3P) weibull distribution for characterization of strength of ceramics showing R-Curve behavior

Strength distribution of advanced ceramics is commonly characterized by two-Parameter (2P) Weibull distribution. However, deviation of strength distribution from 2P-Weibull distribution may occur in ceramics due to various mechanisms. R-curve behavior is one of these mechanisms where increase of fracture resistance with the extension of crack occurs. In such cases, 2P-Weibull distribution may not be the best fitting distribution function based on the goodness-of-fitness tests. This article examines the effectiveness of three-parameter (3P) Weibull distribution function for fitting the strength variation due to R-curve effect by using experimental and virtual strength data. The effect of Weibull parameters, degree of increase in crack resistance and number of samples on effectiveness of fitting via 3P-Weibull distribution is investigated. It is reported that 3P-Weibull distribution function fits the strength distribution better than 2P-Weibull distribution function for materials showing R-curve behavior when the crack resistance curve is steep and Weibull modulus is high. Furthermore, it is shown that at least 100 samples should be used for a reliable estimate when the material exhibits R-curve behavior.     

Caregivers’ attitudes toward potential robot coworkers in elder care

Technological advances in robotics increase progressively. Elder care is one of the work areas which have potential to involve robotic workforce. So, it is important to focus on interaction between humans and potential robot workers to prepare the organization for possible challenges. The current study examined the relationships between trust in robots and anthropomorphism of robots, intention to work with robots and preference of automation levels. For this purpose, 102 caregivers who work for elder care in a nursing home (aged between 19 and 40) participated in an experimental study. According to the results, anthropomorphism of robots did not make any difference in terms of trust in them. Trust in robots was significantly related to intention to work and preference of automation levels. Organizations may consider employees’ trust in robots as an important factor before adapting them to workplace area.

     

The interleukin-10 promoter genotype predicts diastolic dysfunction in maintenance hemodialysis patients

Interleukin-10 (IL-10) predominantly acts as an anti-inflammatory factor. Polymorphisms in the IL-10 gene promoter determine quantitative cytokine production. Doppler echocardiography and tissue Doppler imaging (TDI) are superior to conventional echocardiography to evaluate diastolic dysfunction. The IL-10 gene promoter polymorphism at position (-1082) was studied for its association with conventional and Doppler echocardiographic and TDI parameters in 112 hemodialysis (HD) patients. Blood pressure, serum C-reactive protein (CRP), and albumin levels were also examined for the association study. The genetic association study showed that among the HD patients, there was no difference in the prevalence of systolic and diastolic dysfunction between genotypes on conventional echocardiography. However, using Doppler echocardiography and TDI, high producers for the IL-10 -1082 promoter (-1082/GG) have higher E velocities, E/A values, lateral, and septal E' velocities and a lower isovolumic ventricular relaxation time than low (-1082/AA) and intermediate producers (-1082/GA). Significantly higher levels of serum CRP levels and lower plasma albumin levels were found in low and intermediate producers for the IL-10 -1082 promoter than high producers. The IL-10 genotype may balance the effects of inflammatory cytokines on the myocardium and may be a determinant of LV function in HD patients.     

Morphofunctional structure of the lingual papillae in three species of South American Camelids: Alpaca,guanaco, and llama

The aim of this study was to compare the anatomical and functional characteristics of the lingual papilla among the Camelidae. For this purpose, tongues of alpaca, guanaco, and llama were used. Numerous long and thin filiform papillae were located in the median groove and none were detected on the rest of the dorsal surface of the lingual apex in alpaca. Secondary papillae originated from the base of some filiform papillae on the ventral surface of alpaca tongue. The bases of some filiform papillae of the lateral surface of the lingual apex were inserted into conspicuous grooves in guanaco and tips of filiform papillae on the dorsal surface of the lingual body were ended by bifurcated apex. On the dorsal surface of the lingual apex of llama, there were no filiform papillae but there were numerous filiform papillae on both the lateral margins of the ventral surface of the lingual apex. Fungiform papillae were distributed randomly on dorsal lingual surface and ventral margins of the tongues of all camelid species. Lenticular papillae were located on the lingual torus and varied in size and topographical distribution for each species. Circumvallate papillae had irregular surfaces in llama and alpaca, and smooth surface in guanaco. In conclusion, llama and alpaca tongues were more similar to each other, and tongues of all camelid species displayed more similarities to those of Bactrian and dromedary camels in comparison with other herbivores and ruminants. Microsc. Res. Tech. 79:61–71, 2016. © 2015 Wiley Periodicals, Inc.