防止硫磺储罐的腐蚀

现场安装的硫磺储罐通常用于大量熔融硫磺的临时储存。然而由于腐蚀原因,特别是在正常液位上方的气相腐蚀,储罐的使用寿命十分有限。储罐腐蚀可能有若干机理,最可能的是因为在冷金属表面固体硫磺的沉积和痕量液态水的形成。这两种现象共同导致硫化铁的形成。硫化铁是自燃性物质,除了会造成储罐损坏外,如果突然与氧气接触还可能点燃罐内硫磺。抑制腐蚀的最佳方法是防止固体硫磺在罐壁和罐顶处形成。常规的加热技术,例如内部盘管,能有效地保持硫磺于熔融状态,却不能使蒸气相及罐壁维持足够高的温度。通过采用外部分布式加热系统,可将罐壁、罐顶以及蒸气相温度维持在硫磺凝固点之上,从而消除主要的腐蚀途径。论述潜在的腐蚀机理和操作数据,说明工程加热系统的重要性。     

The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

The increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction. In order to increase the crystallinity of the product the reactions were carried out at 80 °C. We found that hydrotalcite formed in both the alkali-activated slag cements and the fly ash-based geopolymers. Hydroxycancrinite, one member of the ABC-6 family of zeolites, was found only in the fly ash geopolymers. Assuming that the predominantly amorphous geopolymer formed under ambient conditions relates to the crystalline phases found when the mixture is cured at high temperature, we propose that the structure of this zeolitic precursor formed in Na-based high alkaline environment can be regarded as a disordered form of the basic building unit of the ABC-6 group of zeolites which includes poly-types such as hydroxycancrinite, hydroxysodalite and chabazite-Na.     

Practicum training hours: Fact and fantasy.

Over the past five years, practicum experience has received increased attention as an important element in the sequence of training. Questions have arisen about the number of hours being counted and the activities occurring in practicum. This study examined the number of practicum hours accrued by comparing the actual number of direct service hours and total hours to an estimated length of time to complete those hours. Based on self-reports, it was estimated that graduate students spend between 2 and 7 years to accrue their practicum hours with 37.5 to 69.6% of that time in direct service. Implications for the profession, faculty, and students are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SPARC deficiency leads to early-onset cataractogenesis

PURPOSE: To determine the role of SPARC (secreted protein, acidic, and rich in cysteine) in cataractogenesis by examining mice deficient in a matricellular protein SPARC. METHODS: Mice were rendered SPARC-deficient by a targeted disruption of the gene. Slit-lamp microscopy and histology were used to examine the eyes of SPARC-null and wild-type mice from birth to 14 months of age. RESULTS: SPARC-null mice developed opacities in the posterior cortex of the eye as early as 1.5 months after birth. The diffuse cataracts appeared to progress toward the anterior cortex and reached maturity in many animals by 3.5 months of age. Early stages of cataractogenesis in SPARC-null mice included inhibition of normal lens fiber cell differentiation, degeneration of fiber cells, vacuole formation at the equator, and liquefaction of the cortex. No cataracts were detected in wild-type mice up to the age of 8 months. CONCLUSIONS: The early onset of cataracts in SPARC-null mice establishes that the gene is essential to the maintenance of lens transparency.     

Preliminary observations on an intervention program for heavy smokers

Each of 571 smokers selected one of three methods of smoking cessation: group therapy, individual counseling, and hypnosis. One-year results suggest little difference between the three methods in producing ex-smokers. All methods produced an average success rate of approximately 20%. It should be noted, however, that with all types of verbal or verbally related therapy it is not known precisely how these techniques work or whether the outcomes are really a function of what is put into the therapy by the treatment agent and/or the recipient. It was generally found that younger, more educated smokers chose hypnosis; older, more educated smokers chose group therapy; and older, less-formally educated smokers chose individual counseling while the youngest and generally less educated smokers chose to become nonattenders and not take part in therapy. These results have important implications for designing optimal treatment programs which will be acceptable and effective for the greatest number of smokers.     

齿科微晶玻璃的腐蚀机理及溶胶-凝胶防腐蚀涂层研究

利用体外试验方法以及SEM／EDAX、ICP、FTIR等分析技术，对氟硅碱钙石(fluorcanasite,K2Na4Ca5Si12O30F4)齿科微晶玻璃的腐蚀机理，以及溶胶-凝胶Al2O3，、TiO2及ZrO2涂层改善微晶玻璃抗侵蚀的效果进行了比较分析．研究表明，口腔溶液对该齿科微晶玻璃的侵蚀源于溶液中的H3O 离子与微晶玻璃表面的Na 及K 发生迅速的离子交换，从而形成结构疏松的表面富SiO2层，其Si-O网络进而被H2O分子所断开，使SiO2以可溶性硅胶形式溶解于溶液中．此反应导致大量的表面结构缺陷，从而降低了材料的强度和使用寿命。浸泡25天后微晶玻璃表面最终的反应产物是一层低结晶度的颗粒状碳酸羟基磷灰石Cal0(PO4)6(2OH-，CO3^2-)．溶胶-凝胶A12O3涂层具有显著的改善齿科微晶玻璃抗唾液腐蚀的作用。     

Sensitive Mother-to-Adolescent Disclosures After Divorce: Is the Experience of Sons Different From That of Daughters?

This study addressed two main questions: (a) Are adolescent sons and daughters exposed to sensitive maternal disclosures after divorce with similar frequency and in similar detail? and (b) Does gender act as a moderator in the association between maternal disclosures and adolescent adjustment difficulties? Forced-choice and open-ended data were collected from 194 adolescents within 2 years after their parents' divorce. Quantitative analyses revealed that although the majority of adolescents experience some level of maternal disclosure, neither frequency nor detail of maternal disclosure differed as a function of adolescent gender. Frequent and detailed maternal disclosures were associated with adolescent adjustment difficulties, primarily psychological distress. Gender did not moderate that significant association. Qualitative analysis shed light on the link between maternal disclosures and adolescent distress, suggested the importance of how disclosures are made, and revealed several gender differences in reactions to maternal disclosures. Implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation between Indoor and Outdoor Exposure to Fine Particles near a Busy Arterial Road

Abstract Various studies on indoor and outdoor particulate matter in the urban environment in the vicinity of busy arterial roads in the centre of the subtropical city of Brisbane have indicated that the revised United States Environmental Protection Agency National Ambient Air Quality Standards (US EPA NAAQS) for Particulate matter PM_2.5 could be exceeded not only outdoors but also indoors. The aim of this work was to investigate outdoor exposure to submicrometer particles and their relationship with indoor exposure in a hypothetical office building located in the vicinity of a busy arterial road. The outdoor exposure values and trends were measured in terms of particle number in the submicrometer size range and were then recalculated to represent mass concentration trends. The results of this study indicate that exposure to PM_0.7 particles in ambient air close to a busy road often exceeds the levels of the annual and 24-hour US EPA NAAQS PM_2.5 standards. It is likely that exposure to PM_2.5 is even higher, and may significantly exceed these standards.     

Spent nuclear fuel and residential property values: the influence of proximity, visual cues and public information

This article examines whether public knowledge of spent fuel storage at nuclear power plants, and any local adverse risk perceptions that may have occurred, affect the sale price of single-family residential properties. We present evidence from the Rancho Seco, California, plant on residential property values using an hedonic modeling framework. We include a large number of control variables, data with a high level of spatial detail and a number of public information variables in order to model property market effects within a fifteen mile radius of the plant. Our findings indicate that proximity and visual reminders of the plant have some influence on local property markets, and that there is a small media coverage effect on single-family home sale prices. Received: 6 May 1998 / Accepted: 26 May 1999     

Amplification of tunable, picosecond pulses from a single-mode, short cavity dye laser

The design and performance of an Nd⁺³:YAG pumped, short cavity dye laser-dye amplifier system is reported. This system produces narrow bandwidth, broadly tunable picosecond pulses with energies in the millijoule range.