Leaching behaviour of tin with oxygen in recycled phenolsulfonic acid tin plating solutions

The dissolution characteristics of metallic tin with oxygen in recycled phenolsulfonic acid (PSA) tin plating bath to compensate tin consumed during the previous plating operation were investigated using electrochemical methods and leaching experiments at 30 °C. Electrochemical polarization data indicate that the diffusion of dissolved oxygen is the rate determining step and this is confirmed by leaching experiments. The sludge formed due to further oxidation of stannous ions during leaching in PSA tin plating solutions contains approximately 40 wt % Sn.     

Positional small-angle X-ray scattering

Positional small-angle X-ray scattering has been implemented and developed as a new nondestructive technique to study the formation and growth of flaws in polymers. The technique consists of measuring the intensity of scattering at a constant scattering angle while the sample is moved through the incident x-ray beam. Examples of applications of the technique from several different materials are presented.     

Performance of criminal psychopaths on selected neuropsychological tests.

Screening batteries of standard neuropsychological tests were administered to 2 different samples (Ns?=?90 and 167) of male prison inmates. Scores on the Psychopathy Checklist—Revised (R. D. Hare, 1990) were used to divide inmates in each sample into high, moderate, and low psychopathy groups. There were no group differences in test performance in either of the samples, even when the effects of self-reported psychopathology and substance abuse were taken into account. The overall prevalence of both test-specific and global neuropsychological impairment was low and did not vary significantly across the 3 groups. The results provide no support for traditional brain-damage explanations of psychopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimated daily intakes of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) antioxidants in Korea.

The study was conducted to establish the estimated daily intake (EDI) of antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) in Korea. The EDIs were obtained from two sources. One of the estimations was based on the analytical determination of BHA, BHT and TBHQ in 12 food categories (ten food categories for TBHQ) and on individual dietary intake data obtained from the National Health and Nutrition Survey in 1998 (n=11 525, age > 1 year). The other EDIs of BHA, BHT and TBHQ were based on the maximum permitted levels specified in national food standards in Korea and on individual dietary intake data obtained from the National Health and Nutrition Survey in 1998 (n=11 525, age > 1 year). To establish the EDIs based on the analytical determination and on individual dietary intake data, 133 food samples in 12 food categories were selected from the foods considered to be representative sources of BHA, BHT and TBHQ in the Korean diet. Selected samples were analysed by GC with FID. BHA was not detected in any of the samples analysed. BHT and TBHQ were detected in the samples, but the levels were significantly lower than their maximum limits. The EDIs1 of BHT, and TBHQ for average consumers were 0.0156(-3), and 0.0012(-3) mg kg(-1) body weight bw day(-1) and as a proportion of the ADI were 0.0052 and 0.0002%, respectively. For 95th percentile consumers, the EDIs of BHT and TBHQ were 0.0080 and 0.0006 mg kg(-1) bw day(-1), and as a proportion of the ADI were 2.67 and 0.09%, respectively. EDIs for BHA, BHT and TBHQ based on the maximum permitted levels and on individual dietary intake data were 0.04, 0.04 and 0.04 mg kg(-1) bw day(-1), respectively. The EDIs of BHA, BHT and TBHQ for average consumers ranged from 6.00 to 14.42% of the ADI of each antioxidant. According to these results, the EDIs of BHA, BHT and TBHQ in Korea were significantly lower than ADI of these antioxidants established by the JECFA.     

Adsorption kinetics of polyethylene glycol from aqueous solution onto activated carbon

The adsorption equilibrium and kinetics of polyethylene glycol (PEG) in three aqueous systems were examined in this study. Langmuir isotherm was used to satisfactorily predict the adsorption capacity of PEG on activated carbon F-400 and applied to the investigation of adsorption kinetics. The surface diffusion, pore diffusion, and branched pore kinetics models successfully described the adsorption behavior of PEG on F-400 in the completely stirred tank reactor. The pore diffusion coefficients obtained from the pore diffusion model were compared with those computed by the experimental data of the short fixed-bed reactor combined with the assumption of non-hindered pore diffusion. In addition, the effects of initial concentrations of PEG and the relative importance of external and internal mass transfers for the adsorption were also taken into account and discussed in this study.     

汽车盘制动器优化设计热和机械特性的研究(一)

由于热量集中于制动盘的表面造成热弹不稳定性(TEI)而引起热变形.这样可能发生大家知道的低频强烈振动.因为在盘和衬块的接触面间的摩擦系数变化,在摩擦衬决发生尖叫声.通过对热聚集和尖叫现象的联合分析,对高热和机械特性可设计一最佳的盘和摩擦衬块.本文同时考虑了热和机械不稳定性按照盘的厚度,卡钳的加压方式,衬片弧长进行了数值...     

Surface corrosion of steel fibre reinforced concrete

Corrosion of SFRC (Steel Fibre Reinforced Concrete) in an adverse environment, less harmful as compared to corrosion of steel reinforced concrete, is often considered to be of minor importance, however it exists. It can affect the fibres bridging the cracks and then decrease the strength of the concerned structures. As well, it results in the appearance of corrosion spots at exposed surfaces. Then the damaging effect is no longer expressed in terms of resistance, it is only aesthetic. It is especially undesirable in prefabricated structures.The work developed in this paper focuses on this second point: surface corrosion. Fibre reinforced concrete prisms have been subjected to cycles of salt fog (1 week) and drying (1 week). The results obtained demonstrate that with high W/C ratio (0.78), all the fibres which are embedded in concrete less than 1 mm are susceptible to give corrosion spots at the surface. When W/C is reduced to about 0.5, the minimum necessary cover to prevent surface corrosion drops to 1/10 mm or 2/10 mm and further decrease of W/C does not bring extra significant benefit. This result is in agreement with the analysis, by mercury intrusion, of the skin concrete porosity. It confirms a sharp change in the pore diameters when W/C is decreased from 0.78 to 0.48 and a quasi stability when it is varied from 0.48 to 0.36.