Influence of certain physico-chemical treatments on the cookability of pigeon pea (Cajanus cajan)

The influence of sodium hexametaphosphate (SHMP) and trisodium citrate (TSQ on the cookability of split cotyledons (dhal) of pigeon pea was studied. The former was found to be more effective in reducing the cooking time than the latter chemical when added to the cooking water at (85 ± 1)°C at 2% level of concentration. Influence of certain physicochemical treatments involving presoaking, freezing, thawing, and controlled drying on the cookability of the pigeon pea dhal was also investigated. Presoaking in a salt solution followed by either controlled drying alone or freezing, thawing and controlled drying in succession resulted in quick-cooking dhal.     

Magnetic and electrical properties of lanthanum substituted yttrium iron garnets

Polycrystalline yttrium lanthanum iron garnets (Y₃La _x Fe_5-x O₁₂) with varying La substitution (0 ≤ x ≤ 0.5) have been prepared in the pellet form, and studied by X-ray diffraction, magnetization, a.c. susceptibility and electrical resistivity measurements. The lattice constants are determined and the applicability of Vegard’s law has been tested. The saturation magnetization (4 πM _S) decreases very slowly almost linearly with increasing x from x = 0.0–0.5 indicating minimal reduction in ferrimagnetism and least magnetic loss. Variation of saturation magnetic moment per formula unit at 300 K with x can be explained satisfactorily assuming the collinear spin-ordering model. The Curie temperature (T _c) reduces very slowly with increasing x, which is consistent with the observed decrease in 4 πM _S with x. The activation energy (E) decreases very slowly with increasing x for x > 0.1.     

Mechanism of selenium sorption by activated carbon

Selenium, along with mercury and halides, represents one of the most volatile trace metallic emissions from coal‐fired combustors and utility boilers. This study investigates the potential of activated carbon in capturing gas phase selenium species in the low temperature range (125°C to 250°C) and elucidates the mechanism of interaction between selenium species and activated carbon. Selenium dioxide is chosen as the representative selenium species and experimental investigations are carried out in a differential bed reactor to illustrate the mechanism of SeO₂ and carbon Interaction, Activated carbons with different structural properties are studied as adsorbents for selenium dioxide capture at low temperature. The capture mechanism is found to involve both physical and chemical adsorption in the low temperature range. At 125°C, about 1.5 wt% of selenium is captured at equillbrium. Carbon surface analyses and XPS studies confirm the presence of both elemental and oxide forms of selenium on the surface suggesting partial reduction of selenium dioxide to elemental selenium at carbon surface.     

Development and validation of a simple analytical method for the determination of 2,4,6-trichloroanisole in wine by GC–MS

A novel method for the residue analysis of wine spoilage compound 2,4,6-trichloroanisole is reported. Wine (60 ml) was extracted with 2 ml toluene in presence of 24 g MgSO₄ and 6 g NaCl. Cleanup of the toluene phase by dispersive solid phase extraction with mixture of 100 mg CaCl₂, 25 mg primary secondary amine and 50 mg MgSO₄ was effective in minimising co-extractives and matrix effects. Time-of-flight and tandem mass spectrometric parameters were optimised to achieve linearity over 0.25–500 ng ml⁻¹ and method detection limit 0.0083 ng ml⁻¹ which is well below the odour threshold of 0.04 ng ml⁻¹. Recoveries at 0.04, 0.2 and 0.8 ng ml⁻¹ were within 80–110% (±8%). The method was reproducible when tested for Argentinean wines with intra-laboratory Horwitz ratios being <0.20 in white and red wines at both the laboratories of India and Argentina. The method could be successfully applied for incurred wine samples.     

Identification of thiol from 11-(9-carbazolyl)-1-undecyl disulfide by NMR spectroscopy and single step coating of gold nanoparticles

Disulfide-functionalized fluorescent derivative of carbozole named 11-(9-carbazolyl)-1-undecyl disulfide (CBZDS) has been synthesized. Proton nuclear magnetic resonance spectroscopy was used to distinguish thiol from its corresponding symmetrical disulfide. Single step synthesis of gold nanoparticles coated with CBZDS was carried out which resulted in stable monolayers of CBZDS on gold nanoparticles.     

压电双晶片驱动式气动伺服阀性能的研究

提出一种压电陶瓷片直接驱动的气动伺服阀,分析该伺服阀的工作原理,并采用解析法建立其动力学模型。分别用M atlab和AMES im软件对其进行仿真分析。仿真结果表明:该伺服阀的频宽为1 348 Hz,高于传统电磁式伺服阀的;响应时间为2.3 m s,比普通电磁阀快10～15倍;其还具有机械结构简单、抗干扰能力强、动态特性好等特点。     

基于激光位移传感器的光电非接触圆度测量

为了提高圆度测量的效率和准确性,针对目前手工检测效率低等缺点,提出一种以激光位移传感器的测距原理为依据的光电非接触圆度测量方法。与传统方法相比,该方法首先搭建了以精密转台和步进伺服执行机构为主的测量控制系统平台。其次,利用机械装置的相对运动,通过传感器采样测量物体的各测量点的截面信息,用最小二乘圆的评定方法得到各截面测量误差,最终实现圆度误差测量。结果表明,通过仿真获得随机误差系数在对圆度误差测量影响的数学表达式,并验证了测量中存在的系统误差修正方法的正确性。     

Modifications in structural, cation distribution and magnetic properties of Co gamma irradiated Li-ferrite

Polycrystalline samples of Li_0.5Fe_2.5O₄ ferrite precursor were prepared by conventional standard double sintering ceramic technique and then irradiated with three different doses of ⁶⁰Co gamma rays. The crystal structure and phase orientation of the irradiated and unirradiated samples of Li_0.5Fe_2.5O₄ ferrite was done by using X-ray diffraction technique at room temperature. The lattice parameter of the studied samples increased due to the formation of Fe²⁺ ions under the ionizing effect of gamma radiation. The strain in the materials due to the irradiation was calculated from XRD data. Scanning electron microscope (SEM) studies indicate that the irradiation causes amorphization, especially at the grain boundaries. The cation distribution was calculated from XRD data analysis. By using cation distribution structural parameters such as theoretical lattice constant, ionic radii of available sites and the oxygen parameter ‘u’ have been calculated. The estimated cation distribution and other structural parameters shows strong influence of gamma rays on polycrystalline Li-ferrite. The magnetic properties of irradiated and unirradiated lithium ferrite were performed by using pulse field hysteresis loop technique at room temperature. Electrical properties such as diffusion coefficient and dielectric properties were carried out with the influence of gamma irradiation. Activation energy of diffusion process decreased after irradiation. The increase of diffusion coefficient with increasing dose rate of gamma irradiation was reinforced by the increase of Fe²⁺ ions and the displacement of metal ions from its original sites under the effect of gamma irradiation.     

Photoelectrochemical applications of In<Subscript>2</Subscript>Se<Subscript>3</Subscript> thin films by chemical deposition

Indium selenide films have been synthesized by chemical bath deposition method onto stainless steel plate. The configuration of fabricated cell is n-In₂Se₃| NaOH(1 M) + S(1 M) + Na₂S(1 M) |C_(graphite). Characterization of the photoelectrochemical cell was carried out by studying X-ray diffraction, current–voltage and capacitance–voltage characteristics in the dark, barrier height measurements, power output, photoresponse and spectral response. The study shows that the In₂Se₃ thin films are n-type semiconductor. The junction ideality factor was found to be 3.24. The flat band potential and the barrier height were found to be 0.720 V and 0.196 eV, respectively. From the study of power output characteristics, open circuit voltage, short circuit current, fill factor and efficiency were found to be 310 mV, 20 μA, 37.64 and 0.61%, respectively. Photoresponse studies show that the lighted ideality factor is 2.78. Maximum current was observed at 575 nm.