Arc characterization study for submerged arc welding of HSLA (API X80) steel

Journal of Mechanical Science and Technology - The load bearing capacity of weld is highly influenced by the mode of metal transfer which in turn is dependent on welding current and arc voltage....     

Adsorption of gold(III) from waste rinse water of semiconductor manufacturing industries using Amberlite XAD-7HP resin

Advanced hydrometallurgical separation processes are gaining significant importance for the recovery of gold from the aqueous solutions viz. leach liquor of waste electronics, plating material solutions, and waste wash water from electronic industries. In the present investigation, gold adsorption from the waste rinse water of semiconductor manufacturing industries is reported using Amberlite XAD-7HP. For experimental purposes, chloride waste rinse water that contained primarily Au (281 mg/ L) with trace amounts of Cu, Ni, Zn, Sn etc was used. Batch studies were carried out to optimize various process parameters, including contact time, acidity of solution, and resin dosage for the adsorption of gold from the above waste effluent. Adsorption of 92.25% gold was found from the waste solution within a contact time of 30 minutes at an aqueous to resin (A/R) ratio of 25 mL/g and an equilibrium pH of 0.63. In optimal conditions, the loading capacity of resin for gold was observed to be 58.82 mg of gold/g of resin. The gold adsorption phenomena were confirmed by the comparative FT-IR spectroscopic characterization studies of fresh resin and gold loaded resin. Elution tests were carried out for the elution of gold from the gold loaded resin using various ratio mixtures of acetone and 1.0 M HCl. An elution efficiency of 96.96% gold was achieved at an acetone-to-acid ratio of 9. In this condition, gold-enriched solution containing 7,240 mg gold/ L was obtained. The maximum elution of gold was found to be 99.33% using pure acetone in a contact time of 30 minutes. The data obtained will be useful to simulate the continuous gold adsorption process within a column.     

Inhibitive effect of diethylcarbamazine on the corrosion of mild steel in hydrochloric acid

Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), weight loss measurements and atomic force microscopy techniques were used to investigate the inhibitory effect of diethylcarbamazine (DECM) on corrosion of mild steel in HCl solution. The inhibitor showed >90% inhibition efficiency at 5.01 × 10⁻⁴ M. Results obtained revealed that inhibition occurs through adsorption of inhibitor molecules on metal surface without modifying the mechanism of corrosion process. Potentiodynamic polarization studies suggested that it is a mixed type inhibitor, predominantly controls cathodic reaction. Activation parameters (E_a, ΔH and ΔS) and thermodynamic parameters (, and ) were calculated to investigate mechanism of inhibition.     

在表面活性剂存在下铬铁矿表土中镍的微生物萃取(英文)

加入表面活性剂吐温20,用Aspergillus niger对预处理过的印度Sukinda铬铁矿表土在摇瓶中生物浸取镍。考察添加表面活性剂吐温20对黑曲霉菌Aspergillus niger生长及浸镍效果的影响。结果表明,添加低浓度的表面活性剂吐温20对黑曲霉菌从预处理过的铬铁矿表土中提取镍是有利的。通常,Aspergillus niger利用培养基中的碳源来进行细胞代谢,产生有机代谢物,从而生物浸出矿。添加表面活性剂吐温20加速了黑曲霉菌对碳源的消耗,从而改善了镍浸出效果。在预处理矿浆浓度为2%和温度为30°C的条件下,添加表面活性剂吐温20的镍浸取率能达到39%,没有表面活性剂的镍浸取率只有24%。     

Colloid Emulsion of Nanosized Strontium Bismuth Tantalate Powder

A novel colloid-emulsion process has been used to synthesize nanosized strontium bismuth tantalate (SrBi₂Ta₂O₉) particles. During calcination, the desired bismuth-layered structure phase develops at the expense of the pyrochlore phase. Calcining the precursor powder at 750°C for 2 h leads to the complete formation of single-phase layered-structured SrBi₂Ta₂O₉. The powder that is formed consists of nanoparticles with a narrow size distribution and almost-spherical morphology. The crystallinity of the calcined powder increases as the calcination temperature and heating time increases. The developed colloid-emulsion process significantly reduces the SrBi₂Ta₂O₉ particle size, in comparison to conventional process techniques, and results in a uniform microstructure of the obtained powder.