Super porous α-, β-, γ-cyclodextrin cryogels with high active agent loading and controllable release profiles

Cyclodextrins (CDs) are truncated cone-like structures that are natural cyclic oligosaccharides. Here, a simple preparation method for super porous poly(α-CD), poly(β-CD), and poly(γ-CD) cryogels crosslinking with divinyl sulfone at 150%, 100% and 125% mole ratios with respect to the α-CD, β-CD, and γ-CD molecules, respectively, under cryogenic conditions, is reported. The interconnected homogeneous pore distribution of CD-based cryogels with pore sizes in the range of 5–100 μm is confirmed by SEM analysis. The CD-based cryogels weighing 10 mg are determined as hemocompatible with <1% hemolysis ratios and >79% blood clotting indexes; whereas the same materials weighing 1 mg are biocompatible with >75% cell viability on L929 fibroblasts. Additionally, active agent adsorption/delivery efficiencies of CD-based cryogels utilizing two active agents, Bisphenol A (BPA, a carcinogenic compound) and Curcumin (CUR, a polyphenolic compound), are individually evaluated. It was revealed that p(γ-CD) cryogels exhibited the highest active agent loading capacity for BPA, 87 ± 13 mg/g, whereas p(α-CD) cryogels showed the highest loading capacity for CUR, 136 ± 4 mg/g. Moreover, the active agent release from p(α-CD), p(β-CD), and p(γ-CD) cryogel networks at pH 7.4 and 37°C were determined as 40.6 ± 2, 35.3 ± 2, and 34 ± 1 mg/g for BPA, and 1.07 ± 0.2, 1.27 ± 0.1, and 1.37 ± 0.1 mg/g for CUR, respectively, within 96 h.     

The effect of recycling number on the mechanical,chemical, thermal,and rheological properties of PBT/PC/ABS ternary blends: With and without glass‐fiber

The recycling possibilities of poly(butylene terephthalate)/polycarbonate/acrylonitrile–butadiene–styrene (PBT/PC/ABS) ternary blend with and without glass‐fiber content were investigated using repeated injection molding process. In this study, PBT/PC/ABS ternary blends were reprocessed at five times and the results were presented after each recycling process. The recycling possibility of PBT/PC/ABS ternary blend was evaluated by measuring the mechanical, chemical, thermal, and rheological properties. Mechanical properties were determined by the tensile strength, yield strength, strain at break, elastic modulus, impact strength, flexural strength, and flexural modulus. Chemical and thermal properties were evaluated by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, and scanning electron microscopy. Rheological properties of the ternary blends were studied by melt flow index measurement. From the results, it was found that mechanical properties of recycled composites were better than virgin PBT/PC/ABS ternary blends. POLYM. COMPOS., 35:2074–2084, 2014. © 2014 Society of Plastics Engineers     

Neural computing models for prediction of permeability coefficient of coarse-grained soils

Correlations are very significant from the earliest days; in some cases, it is essential as it is difficult to measure the amount directly, and in other cases it is desirable to ascertain the results with other tests through correlations. Soft computing techniques are now being used as alternate statistical tool, and new techniques such as artificial neural networks, fuzzy inference systems, genetic algorithms, and their hybrids were employed for developing the predictive models to estimate the needed parameters, in the recent years. Determination of permeability coefficient (k) of soils is very important for the definition of hydraulic conductivity and is difficult, expensive, time-consuming, and involves destructive tests. In this paper, use of some soft computing techniques such as ANNs (MLP, RBF, etc.) and ANFIS (adaptive neuro-fuzzy inference system) for prediction of permeability of coarse-grained soils was described and compared. As a result of this paper, it was obtained that the all constructed soft computing models exhibited high performance for predicting k. In order to predict the permeability coefficient, ANN models having three inputs, one output were applied successfully and exhibited reliable predictions. However, all four different algorithms of ANN have almost the same prediction capability, and accuracy of MLP was relatively higher than RBF models. The ANFIS model for prediction of permeability coefficient revealed the most reliable prediction when compared with the ANN models, and the use of soft computing techniques will provide new approaches and methodologies in prediction of some parameters in soil mechanics.     

Effect of CR and FT-paraffin versus SBS modification in terms of conventional and rheological properties

In this study, the rheological and conventional properties of binders prepared with crumb rubber (CR) and FT-paraffin were compared to styrene-butadiene-styrene (SBS)-modified binders’ properties. The objective of this study was to determine which modified binders in different combinations of the CR and the FT-paraffin exhibited better performance than the SBS-modified binders, in terms of conventional and rheological properties. Results showed that the additives exhibited different performances for different types of tests. Many of the combinations including the common usage of the CR and the FT-paraffin performed better at high temperature than the SBS modification. Overall, the test results show that the binders prepared by 6% CR with 3 and 4% FT-paraffin and those prepared with 8% CR with 3% FT-paraffin were better binders than the 4% SBS-modified binder, in terms of low and high temperature properties.     

Modular Deformable Steam Electricity Cogeneration System with Photothermal,Water, and Electrochemical Tunable Multilayers

Capturing solar energy for thermal conversion in a highly efficient manner for steam‐electricity cogeneration is particularly opportune in the context of optimal solar energy utilization for concurrent water‐energy harvesting. Herein, an integrative photothermal evaporator/thermogalvanic cell with the desired optical, heat, water, and electrochemical management for synergistic steam‐electricity production is reported. Versatile layer by‐layer assembly is employed to integrate a hydrogel/metal‐oxide/polymer into a multilayer film with individually addressable thickness, composition, and structure. As such, the ultimate integrative multilayer film cell demonstrates a unified high surface area and conductive electrodes, broadband absorption, rapid water suction‐ion exchange, and thermal insulation properties. Thus, the designed cell immensely suppresses heat losses, achieving a high solar thermal conversion efficiency of 91.4% and maximum power outputs of ≈1.6 mW m^?2. Additionally, the self‐floating, deformable, modular integral device presents appealing attributes such as salt‐rejection for viable seawater desalination, high mechanical stability, and resilience to demanding operating conditions, and configurable on‐demand/point‐of‐use tandem structure to maximize clean water and power generation value per area. This integrated strategy may provide prospective opportunities to reduce dependence on fossil fuels and freshwater inputs and solutions for renewable and decentralized clean water and electricity.     

A direct borohydride-peroxide fuel cell-LiPO hybrid motorcycle prototype: Investigation of short-term behavior of DBPFC stack – I

In the present study, a safer and more performance 270?W Direct Borohydride/Peroxide Fuel Cell (DBPFC) Stack has been constructed for an electrical hybrid motorbike application. Performance tests were carried out with single cell and 5–10–25?cell stacks. Performance loss has been not observed while stacking DBPFC because of the Independent Cell Liquid Distribution Network (ICLDN) system and special bipolar plate design. The power densities have been approximately 120?mWcm^?2 for a single DBPFC and 25-cell DBPFC stack without any stacking loss. Additionally, the stack temperature has been controlled by keeping the oxidant concentration low, and it has been maintained at approximately 52?°C without using a cooling system. The short-term performances of the 25-cell DBPFC stack have been tested over 25?min and 50?min, which showed that the performance and stack security of the DBPFC are highly related to the oxidant properties, such as the concentration, temperature and feed type.     

Ultrasound‐assisted bioscouring of cotton

In this study, the effects of ultrasound on the bioscouring of cotton by alkaline pectinase were examined. Conventional alkaline scouring was considered as the control treatment, and two different sources of ultrasound, an ultrasonic bath and an ultrasonic homogeniser, were tested, along with the enzymatic scouring process. Results indicated a clear increase in the efficiency of the enzymatic scouring process when the ultrasonic homogeniser was used: wettability time and wicking distance after ultrasonic homogeniser‐assisted bioscouring were much better than for enzymatic scouring without the use of ultrasound energy and almost the same as when conventional alkaline scouring was employed. Ultrasonic bath‐assisted enzymatic bioscouring gave slightly better results than enzymatic scouring without sonication. Reasons for the difference in efficacy of the ultrasound sources were postulated. Weight loss was increased by the use of ultrasonic equipment during enzymatic scouring. Fabric thickness and fabric strength was not significantly affected by the scouring processes. The environmental impact of the processes was also monitored by chemical oxygen demand measurement of the treatment liquors. Conventional alkaline scouring resulted in the highest environmental impact. Ultrasonic homogeniser‐assisted bioscouring also led to slightly higher chemical oxygen demand loads than other enzymatic processes owing to the more efficient removal of impurities.     

Mechanical Properties and Corrosion Behavior of As-Cast Mg-Zn-Zr-(La) Magnesium Alloys

The effects of La content on the mechanical properties and corrosion behavior of as-cast Mg-Zn-Zr (ZK) magnesium alloys were investigated. The results showed that La addition to ZK60 alloy resulted in a considerable grain refinement and an increase in the volume fraction of second phases by formation of Mg-Zn-La ternary phase. The tensile tests were performed at both room and elevated temperatures. At room temperature, the yield and tensile strengths and elongation-to-fracture significantly increased with 0.2 wt.% La addition, then deteriorated slightly with increasing La additions above 0.2 wt.%. At 200 °C, the yield and tensile strengths continually improved and elongation-to-fracture decreased with increasing La content due to the presence of thermally stable Mg-Zn-La phase. Immersion and electrochemical corrosion tests revealed that the formation of Mg-Zn-La phases led to a higher amount of cathodic sites and preferential corrosion propagation, and thus a decrease in the corrosion resistance of ZK60 alloys.     

Wear behavior of as-deposited and oxidized ternary (Zr,Hf)N coatings

In the present study, the tribological performance of ternary (Zr,Hf)N coatings, whose Hf content was varied between 0 and 21 wt pct, has been systematically examined in the as-deposited and oxidized conditions. Coatings were applied on AISI D2 tool steel plates by arc physical vapor deposition (PVD). Oxidation was conducted at 400 °C for times up to 12 hours in air. Wear tests revealed pronounced improvement in the wear resistance with increasing Hf content in the as-deposited coatings. Oxidation for 12 hours yielded more than a fourfold increase in wear resistance. The beneficial effect of Hf on wear resistance decreased upon oxidation.     

Evaluation of surface settlements in the Istanbul metro in terms of analytical, numerical and direct measurements

In urban areas, the use of pre-support in shallow tunnels is increasing in order to improve the excavation stability and reduce ground settlements induced by the tunneling. This paper describes the effects of pipe roofing on surface settlements and evaluates the settlements associated with the twin tunnels in the Istanbul metro in terms of numerical, semi-empirical and measured values. FLAC3D was used for the numerical modeling and the method suggested by Herzog for the semi-empirical solution. The numerical results indicate that the tunnel roof formed by the pipe roofing provides a restraining effect, reducing deformation and ground surface settlement by up to 65?%. Herzog’s model yields higher maximum surface settlements than those observed. When modified to include the effect of pipe roofing and the distance between the pipes however, there is good agreement between the direct measurements and the values predicted by the numerical and modified Herzog models.