Thermodynamic simulation of performance of a dual cycle with stroke length and volumetric efficiency

This article presents finite-time thermodynamics analysis of an irreversible air standard dual cycle. An irreversible dual cycle model which is more close to practice is established. In this model, the effects of stroke length and volume efficiency by considering the nonlinear relation between the specific heats of working fluid and its temperature, the frictional loss, the internal irreversibility, and heat transfer loss are analyzed. The results show that if compression ratio is less than certain value, the power output increases with increasing stroke length, while if compression ratio exceeds certain value, the power output first increases and then starts to decrease with increasing stroke length. With further increase in compression ratio, the increase of stroke length results in decreasing the power output. The results also show that, throughout the compression ratio range, the power output increases with the increasing volumetric efficiency. The results obtained in this study are of importance to provide good guidance for performance evaluation and improvement of practical internal combustion engines.     

Separation of Cd(II) and Ni(II) ions by supported liquid membrane using D2EHPA/M2EHPA as mobile carrier

The separation of Cd(II) and Ni(II) ions was studied in an aqueous sulphate medium using supported liquid membrane (SLM). D2EHPA/M2EHPA was used as a mobile carrier, microporous hydrophobic PTFE film was used as a solid support for the liquid membrane, and the strip phase was sulphuric acid. The effects of different parameters such as feed concentration, carrier concentration, feed phase pH, and strip phase pH on the separation factor and flux of Cd(II) and Ni(II) ions were studied. The optimum values obtained to achieve the maximum flux were 5.0 for feed pH, 40 vol. % for D2EHPA/M2EHPA concentration in the membrane phase, 0.5 for strip pH, and 0.012 mass % for feed concentration. Under these optimum conditions, the flux values of Cd(II) and Ni(II) were 15.7 × 10^?7 kg m^?2 s^?1 and 2.6 × 10^?7 kg m^?2 s^?1, respectively. The separation factors of Cd(II) over Ni(II) were studied under different experimental conditions. At a carrier concentration of 10 vol. % and feed concentration of 0.012 mass %, the maximum value of 185.1 was obtained for the separation factor of Cd(II) over Ni(II). After 24 h, the percentages of the extracted Cd(II) and Ni(II) were 83.3 % and 0.45 %, respectively.     

Fabrication and characterization of highly crystalline mordenite membranes on α-alumina disks via a seeded in situ template-free hydrothermal treatment

A template-free seeded short-time in situ hydrothermal treatment was carried out in a brass autoclave to synthesize crystalline mordenite (MOR) membranes on alumina-silicate disk supports with micro-scale pores. According to XRD analysis, MOR was the only zeolitic material present in the membrane layers on the supports. SEM examination of the membranes showed three different layers of the membrane thickness: (i) support sub-layer, (ii) mix penetrated mid-layer, the MOR crystals filling the pores among the support (about 4–5 μm), and (iii) MOR top-layer (about 4–5 μm). The crystalline bonds between MOR crystals of the membrane top-layer and the crystals of the support were clearly observed within the mid-layer. The continuous top-layer of zeolitic membrane was formed by many large and well-shaped crystals. The seeding treatment significantly enhanced the formation of MOR crystals onto the surface of the supports. EDAX analysis showed a Si/Al ratio of 6.8 for the MOR layer of the membrane. Due to their hydrophilic natures, the polycrystalline MOR membranes were found to be selective for continuous dehydration of different EtOH–water mixtures through an adsorption–diffusion–desorption mechanism. Both total permeation flux and separation factor of the membrane were found to increase by increasing temperature and water concentration of feed. The continuity and high crystallinity of the membrane top-layer led to the fairly high dehydration of EtOH. It was found that there was no pinhole within the layer and the morphology of the membrane was almost defect-free.     

Characterization of Mazuj galls of Quercus infectoria tree as green corrosion and scale inhibitor for effective treatment of cooling water systems

Research on Chemical Intermediates - The corrosion and scale inhibition efficiency of Mazuj gall extract in simulated cooling water has been evaluated. Potentiodynamic polarization, electrochemical...     

Application of a dispersive micro‐solid‐phase extraction method for pre‐concentration and ultra‐trace determination of cadmium ions in water and biological samples

A method for the trace determination of cadmium ions in water, human urine and human blood serum samples using ultrasonic‐assisted dispersive micro‐solid‐phase extraction (UA‐D‐μSPE) was developed. Silica‐coated magnetic nanoparticles were coated with polythiophene, and the resulting sorbent was characterized using thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X‐ray diffraction. Following UA‐D‐μSPE, cadmium ions were quantified using graphite furnace atomic absorption spectrometry. A Box–Behnken design was used for optimization of important sorption and desorption parameters in UA‐D‐μSPE: in the sorption step, pH of solution, sorption amount and sonication time for sorption; in the desorption step, concentration of eluent, volume of eluent and sonication time. The optimum conditions for the method were: pH of solution, 7.5; sonication time for sorption, 3 min; sorption amount, 35 mg; type and concentration of eluent, HCl and 1.1 mol l^?1; volume of eluent, 360 μl; sonication time for desorption, 110 s. Under the optimized conditions the limit of detection and relative standard deviation for the detection of cadmium ions by UA‐D‐μSPE were found to be 0.8 ng l^?1 and <6%, respectively.     

In Vitro Evaluation of Zn–Norfloxacin Complex as a Potent Cytotoxic and Antibacterial Agent, Proposed Model for DNA Binding

A tetrahedral Zn(II) complex with the second generation fluoroquinolone, norfloxacin, was prepared and characterized (NOR–Zn complex, NZC). The antibacterial efficiency of the NZC was tested on two Gram-positive and four Gram-negative bacteria by minimum inhibitory concentration method. The cytotoxic potential of NZC on MDA (human breast adenocarcinoma), Caco-2 (human colon adenocarcinoma), and Hela (human cervix carcinoma) cell lines was studied. The DNA interaction property of the NZC has been investigated using UV–vis, fluorescence, Fourier transform infrared, as well as cyclic voltammetry methods. Intrinsic binding constant (K _b ), thermodynamic, and other spectroscopic and voltammetric data indicate that the NZC has more affinity for DNA than for norfloxacin and interacted with DNA via two modes: electrostatic and outside hydrogen binding. The proposed DNA binding mode supports the large enhancement in the cytotoxicity and antibacterial activity of NZC.