Thermal Stability Investigation of Synthesized Epoxy-Polyurethane/Silica Nanocomposites

Silicon - In this research, epoxy polyurethane-nano silica nanocomposites have been synthesized using an in-situ method, for which SiO2 nanocomposites had been initially ready in N,...     

Thermo-oxidative aging of epoxy coating systems

The thermo-oxidative behavior of unformulated (unfilled) samples of epoxy coatings has been studied at five temperatures ranging from 70 °C to 150 °C. Two epoxy networks based on diglycidyl ether of bisphenol A (DGEBA), respectively, cured by jeffamine (POPA) or polyamidoamine (PAA) were compared. Infrared spectrophotometry (IR), differential scanning (DSC) and sol–gel analysis (SGA) were used to monitor structural changes.     

Simultaneously energy production and dairy wastewater treatment using bioelectrochemical cells: In different environmental and hydrodynamic modes

A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell (MFC), was used to fabricate two MFCs, with a few changes for cost reduction and ease of construction. Performance and electrochemical characteristics of MFCs were evaluated in different environmental conditions (in complete darkness and presence of light), and different flow patterns of batch and continuous in four hydraulic retention times from 8 to 30 h. Changes in chemical oxygen demand, and nitrate and phosphate concentrations were evaluated. In contrast to the microbial fuel cell operated in darkness (D-MFC) with a stable open circuit voltage of 700 mV, presence of light led to growth of other species, and consecutively low and unsteady open circuit voltage. Although the performance of theMFC subjected to light (L-MFC)was quite lowand unsteady in dynamic state (internal resistance = 100 Ω, power density = 5.15 W·m^-3), it reached power density of 9.2 W·m^-3 which was close to performance of D-MFC (internal resistance = 50 Ω, power density = 10.3 W·m^-3). Evaluated only for D-MFC, the coulombic efficiency observed in batch mode (30%) was quite higher than the maximum acquired in continuous mode (9.6%) even at the highest hydraulic retention time. In this study, changes in phosphate and different types of nitrogen existing in dairy wastewater were investigated for the first time. At hydraulic retention time of 8 h, the orthophosphate concentration in effluent was 84% higher compared to influent. Total nitrogen and total Kjeldahl nitrogen were reduced 70% and 99% respectively at hydraulic retention time of 30 h, while nitrate and nitrite concentrations increased. The microbial electrolysis cell (MEC), revamped from D-MFC, showed the maximum gas production of 0.2 m³ H₂·m^-3·d^-1 at 700 mV applied voltage.     

Newly designed polyacrylamide/dextran gels for electrophoresis protein separation: synthesis and characterization

Newly designed gels for electrophoresis protein separation were synthesized from acrylamide, N,N′‐methylenebis (acrylamide) and dextran mixtures. Radical polymerization was initiated by ammonium persulfate and N,N,N′,N′‐tetramethylethylenediamine. The time dependence of absorbance during polymerization was monitored using UV‐visible spectroscopy. The exothermic polymerization process exhibited a sharp rise of temperature reminiscent of the Trommsdorff effect. The swelling kinetics of the synthesized gels was examined in deionized water and buffer solutions. One of the challenges was to find an alternative to commercial products, sold as mixtures with no detailed chemical contents, commonly used in sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS‐PAGE) for protein separation. For this reason, a systematic comparison was made of the properties of one of the most commonly used commercial gels, Duracryl^? from Genomics Solution Inc., and those of the synthesized polyacrylamide/dextran gels. Copyright © 2011 Society of Chemical Industry     

Open circuit voltage profiling as diagnostic tool during stack lifetime testing

A 10-cell Mk 9 stack was characterized using current/voltage mapping during automotive drive cycle testing. A minimally invasive current mapping technique was used to determine localized polarization curves which together with open circuit voltage (OCV) profile measurements provide useful information about crossover leak formation and location. Through a systematic variation of reactant gas pressures it is further possible to distinguish between electrical shorts, diffusive and convective leaks.     

Bending analysis of functionally graded annular sector plates by extended Kantorovich method

The small deflection equation for isotropic and non-homogenous thin annular sector subject to transverse loading is derived in polar coordinate. The Poisson’s ratio of the plate is assumed to be constant, but the Young’s modulus varies continuously through the radial direction according to the power-law function. A closed-form solution with fast convergence rate is obtained using the extended Kantorovich method and the classical theory of thin plates (Kirchhoff theory). The validity and accuracy of results are examined by resolving the problem using commercial finite element code ABAQUS and a good agreement between them is obtained for either deflection or stress resultants.     

Investigation on the effects of microwave and conventional heating methods on the phytochemicals of pomegranate (Punica granatum L.) and black mulberry juices

Black mulberry and pomegranate juices were concentrated by conventional and microwave heating at different operational pressures (7.3, 12, 38.5, and 100 kPa). The effects of each heating method on the phytochemical changes (total anthocyanin content and antioxidant activity) of juices were investigated. The effect of various heating methods on the profile of the pomegranate anthocyanins were conducted using high-performance liquid chromatography–mass spectrometry (HPLC–MS). The main anthocyanins of pomegranate quantified by HPLC–MS were cyanidin, delphidin, pelargonidin, 3-glucoside, and 3, 5-diglucoside. In black mulberry juice, the final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at 100, 38.5, and 7.3 kPa respectively and the final pomegranate juice concentration of 40° Brix was achieved in 140, 127, and 109 min at 100, 38.5, and 12 kPa respectively by using a rotary evaporator. Applying microwave energy decreased the required times to 115, 95, and 60 min for black mulberry juice and to 118, 95, and 75 min for pomegranate juice. Results showed that anthocyanin degradation and consequently decrease in antioxidant activity were more pronounced in rotary evaporation compared to microwave heating method.