LIQUID PHASE CO-OXIDATION OF THIOPHENOL AND STYRENE BY OXYGEN AND t-BUTYL HYDROPEROXIDE

ABSTRACT

Instability problems in both shale and petroleum derived middle distillate jet fuels have been correlated with the presence of peroxidic species. Although a good body of knowledge exists concerning the formation of peroxides in the liquid phase, relatively little is known about the reaction/ decomposition pathways available when other functional groups are present, since sulfur is the most abundant heteroatam present in jet fuels, the reaction of t-butyl hydroperoxide (tBKP) and/or oxygen with thiophenol in the presence of the active olefin, styrene, was examined in deaerated benzene at 120°C. The complex product mixture was analyzed by combined capillary column GC/MS. Major products included acetone, t-butanol and isdbutylene from the tBHP. Thiophenol and styrene combined to form addition products. Phenyl disulfide was observed from the thiophenol. The results indicated that although the product slate was complex, it was possible to explain the product mix in terms of a few competing reactions.     

Is HIV/AIDS in Africa distinct? What can we learn from an analysis of the literature?

This paper investigates, through an analysis of the published literature, the notion held by several people that HIV/AIDS in Africa is unique. Using co-word and multidimensional scaling (MDS) analyses of MEDLINE-extracted HIV/AIDS records, this study used five lists of terms to investigate the related-ness of various factors and diseases to HIV/AIDS. The lists consisted of risk factors, sexually transmitted diseases, tropical diseases, opportunistic diseases, and pre-disposing factors. Data (i.e. words.txt — consisting of keywords/phrases describing the aforementioned factors and diseases; and text.txt — containing HIV/AIDS papers’ titles) were analyzed using TI computer-aided application software, developed by Leydesdorff. Results revealed that several factors and diseases that are pre-dominant in Sub-Saharan Africa exhibited strong and high pattern of co-occurrences with HIV/AIDS, implying close associated-ness with the epidemic in the region. Further areas of research, whose results will be used to make conclusive observations and arguments concerning the uniqueness of HIV/AIDS in Sub-Saharan Africa, are recommended.     

Comparing problem formulations for coupled sets of components

This paper presents several formulations and comparative test results for problems involving the general paradigm of coupled sets of components (CSoC). This paradigm is general enough to include systems of systems (SoS) under any of the various definitions, as well as multidisciplinary design optimization (MDO). It is assumed that a CSoC involves a (potentially inactive) coordinating component, or “Central Authority”, and one or more, potentially interacting, subordinate components. The formulations differ in the amount of control given to the CA versus the autonomy granted to the subordinate components. In this generality, satisfaction of equilibrium conditions replaces the optimality condition in defining a solution. A solution still requires feasibility of all constraints. The desirability of a particular equilibrium point depends on the specific problem being studied and the component algorithms used to obtain that equilibrium. These concepts are illustrated using comparative test results for several of the formulations on a NASA-generated, public domain, aircraft conceptual design problem.     

Robust smoothing: Smoothing parameter selection and applications to fluorescence spectroscopy

Fluorescence spectroscopy has emerged in recent years as an effective way to detect cervical cancer. Investigation of the data preprocessing stage uncovered a need for a robust smoothing to extract the signal from the noise. Various robust smoothing methods for estimating fluorescence emission spectra are compared and data driven methods for the selection of smoothing parameter are suggested. The methods currently implemented in R for smoothing parameter selection proved to be unsatisfactory, and a computationally efficient procedure that approximates robust leave-one-out cross validation is presented.     

何时以及如何结束IT项目

许多制造业IT项目没有完成，这不一定是因为他们失败了，而是由于不断变化的需求、不断变化的商业环境、公司合并或是由于产品和工艺方面的变化。懂得何时结束一个项目是重要的，但同样重要的是知道在结束一个项目时应该怎么办。     

Investigations into Corrosion Resistance of Decorative Nickel and Chromium Electrodeposits

The results of accelerated corrosion tests, outdoor exposure tests and more fundamental electro-chemical studies have been critically compared as a means of predicting corrosion resistance of nickel+chromium electrodeposits in service. The aim was to compare the relative merits in British atmospheres of some of the various alternative nickel and chromium systems available and to ascertain which of the commonly used accelerated tests placed these systems in the same order of merit as did outdoor exposure. All tests were performed with plated steel panels, some of which were deformed before exposure. The coating systems which gave the best corrosion protection in all outdoor trials were found always to include the thicker chromium deposits, but while crack-free chromium was best on static exposure, micro-cracked chromium was good in both static and mobile conditions. Duplex nickel gave much better protection during mobile tests than on static exposure. The Corrodkote test was the most generally applicable rapid accelerated corrosion test for assessing plated steel. The acetic acid salt spray test gave results which correlated most closely with those obtained on outdoor exposure but takes longer to perform.     

Field response of Ips paraconfusus,Dendroctonus brevicomis,and their predators to 2-methyl-3-buten-2-ol,a novel alcohol emitted by ponderosa pine

Methylbutenol (MBO) is a major component of the aggregation pheromone of the European spruce beetle Ips typographus and also has been found to be emitted in large amounts by several species of pine native to western North America. This study investigates the influence this signal may have on the behavior of North American bark beetles and examines whether MBO functions as a defensive compound for emitting pines. The response of two North American bark beetles (Ips paraconfusus and Dendroctonus brevicomis) and their predaceous beetles (Trogositidae and Cleridae) to MBO, pheromone, and monoterpenes in varying release rates was investigated in the field using Lindgren funnel traps. MBO exhibited no repellent properties when tested alone, nor did MBO appear to have any effect on the aggregation response of these bark beetles and their predators to their pheromones. These results provide no support for a defensive function of MBO.