Occurrence of Lawn Care and Agricultural Pesticides in the Don River and Humber River Watersheds (1998–2002)

Between 1998 and 2002, surface water samples were collected from several sites in the Don River and Humber River watersheds, both tributaries to Lake Ontario, and analyzed for a variety of pesticides, including those used for urban lawn care. Analyses included 152 pesticide active ingredients and eight metabolites. Samples were collected during base flow periods (i.e., dry events) and rainfall events (i.e., wet events). The objectives of the study were to determine which pesticides were detectable, whether there was a difference in the detection frequency between the two watersheds and between upstream and downstream in each river, and whether precipitation influenced the frequency of detection. Eleven pesticides and one metabolite were detected in surface waters of the Don and Humber rivers or their tributaries, with approximately 72% of samples containing at least one pesticide attributable to lawn care use. The pesticides and pesticide metabolite detected in this study included 2,4-D, atrazine, bromacil, carbofuran, chlorpyrifos, cypermethrin, diazinon, dicamba, MECOPROP, metolachlor, metribuzin, and an atrazine metabolite (des-ethyl atrazine). Four pesticides exceeded federal or provincial water quality guidelines/objectives. Diazinon exceeded the provincial water quality objective in 28% of the samples taken. For the three other pesticides (atrazine, carbofuran and chlorpyrifos) exceedance of a water quality criteria occurred in less than 1% of the samples.     

Long-term recovery of pressurized water reactors following a large break loss-of-coolant accident

The U.S. Nuclear Regulatory Commission recently identified a possible safety concern for pressurized water reactors. Following the reflood phase of a large break loss-of-coolant accident, long-term cooling of the reactor core may not be ensured. Specifically, the concern is that, for a pump discharge cold leg break, the loop seals in the reactor coolant pump suction piping will refill with liquid and the post-reflood steam production may depress the liquid levels in the downflow sides of the loop seals. A loop seal depression would cause a corresponding depression of the core liquid levels and possibly a fuel rod heatup in the upper core region. This paper is intended as an introduction of the safety issue that: (1) describes the important aspects of the problem, (2) provides an initial analysis of the consequences, and (3) discusses ongoing work in this area. Because the elevation of the loop seals is near the mid-core elevation in plants of Westinghouse design, the concern is greatest for those plants. There is less concern for most plants of Combustion Engineering design, and likely no concern for plants of Babcock and Wilcox design. This issue was addressed by employing both steady-state and transient systems analysis approaches. Two approaches were used because of uncertainties regarding actual reactor coolant system behavior during the post-reflood period. The steady-state approach involved the development and application of a simple computer program to investigate reactor coolant system behavior assuming quiescent post-reflood conditions. The transient systems approach involved investigating this behavior using the RELAP5/MOD2 computer code and a comprehensive RELAP5 model of a Westinghouse pressurized water reactor. The steady-state analysis indicated only a moderate fuel rod heatup is possible. The transient systems analysis indicated boiling and condensation-induced flow oscillations are sufficient to prevent fuel rod heatup. Analysis uncertainties are discussed.     

解放前我国学者对新疆石油地质的调查和研究

20世纪初，随着近代地质学在中国的形成和发展，一些学者开始了对新疆石油地质的调查和研究，30年代末以前，翁文灏，章鸿钊等学者利用文献和间接获得的资料，对新疆石油资源进行了宏观考察和若干重要油苗的地质研究；40年代开始，黄汲清等地质家在新疆进行实地考察，对独山子油田进行了详细研究，并在南北疆部分地区进行了路线性石油地质调查。     

Coulter counting and light diffraction analysis applied to characterisation of oil-water emulsions

Coulter counting and light diffraction techniques were successfully applied to the characterisation of the droplet concentration and size distribution in camphene-water and cyclohexane-water emulsions. Both of these techniques required a dilution of the emulsion prior to analysis, and it was found that the destabilizing effect on the droplets of such dilution could be overcome by performing the analyses at temperatures below the melting point of the oil phase. The storage stability of the camphene-water samples at 60 degrees C was reasonably good with a 5-20% change in the investigated parameters over a 24 h period. At room temperature camphene-water samples left to stand undisturbed were unaffected after 24 h, while continuous mixing of the emulsion on a roller board brought about a rapid amalgamation of the particles into larger aggregates. This fusion process was fully described only with the light diffraction analysis due to the broader measuring range of this technique. However, analysing emulsions with a droplet size range covered by both techniques gave identical results.     

An experimental investigation of triboelectrification in cohesive and non-cohesive pharmaceutical powders

A detailed experimental investigation has been undertaken of the triboelectrification process of the pharmaceutical excipient alpha-lactose monohydrate and selected drugs. Particle charge studies involved the design and construction of an apparatus to incorporate pneumatic powder feed, triboelectric charging via a cyclone separator and simultaneous powder charge (Q) and mass (M) measurements using a modified Faraday well. Preliminary studies showed the charging of the selected materials to be unaffected by relative humidity up to 84%, due to the very low hygroscopicity of the powders. Experiments using lactose size fractions with brass, steel and cellulose contact charging surfaces conducted at different feeder gas pressures, gave net electronegative specific charge values (Q/M) for the metal surfaces, and electropositive values for cellulose. Specific charge increased linearly with gas pressure for the metals, and non-linearly for cellulose. Samples of micronised lactose and beclomethasone dipropionate (BDP) showed more tendency than unmicronised samples to adhere to the contact surface which resulted in more complex charging processes. A novel system to analyse the charge and mass data in further detail was developed, giving relative Q/M values at unit time intervals. It is proposed that this will overcome the limitations of reliance on the final net specific charge value. Preliminary results indicated differences in the charging mechanism for lactose in contact with the two metal surfaces.     

Psoriasis of the nails associated with disability in a large number of patients: results of a recent interview with 1,728 patients

We present the first case of esophagogastric devascularization and esophagogastric transection using a stapler through laparoscopic surgery. The procedure was performed in a 71-year-old diabetic woman with alcoholic liver cirrhosis (Child-Pugh B class), portal hypertension, bleeding grade III esophageal varices, and a previous bleeding episode. The surgical technique was carried out without problems, and the patient had an excellent postoperative condition. Esophagogastric devascularization with esophageal transection using a stapler through laparoscopic surgery is a feasible technique that accomplishes the same and all objectives of the open procedure. Operative time in both methods is the same, whereas surgical trauma, inmunologic depletion, amount of transfused blood, pain, use of analgesics, and hospital stay are reduced in the laparoscopic technique.