利用石棉尾矿制造微晶玻璃装饰板的研究

似石棉尾矿为主要原料，经熔制、成型、热处理和磨光等工序制造的微晶玻璃装饰板，尾矿掺量可高达60％，产品物理化学性能指标优于天然大理石和花岗石。本方法工艺简单，参数合理，生产条件成熟，是石棉尾矿开发利用的一条有效新途径。本文主要探索了它的配方和熔制、成型及热处理制度。     

Plant health clinics in Bolivia 2000—2009: operations and preliminary results

Smallholder farmers need information on plant diseases. Ten plant health clinics (Postas para Plantas) evolved in Bolivia after 2000 and are still operating due to the efforts of three local institutions. The plant clinics receive any problem, on any crop, and give written and verbal recommendations, immediately if possible. Many clinics are held at weekly farm fairs, where villagers from many surrounding communities can seek help. The clinic staff write fact sheets for farmers on common problems. From 2000 to early 2009 the clinics received more than 9000 queries on over 100 crops with potato comprising two thirds of the queries, followed by peach, tomato and broad bean. Potato tuber moth and potato weevil were by far the most dominant plant health problems in the high Andes, but not in lowland areas. The diversity of crops and problems are a big challenge to the clinic staff. With basic training and practical experience they learn to diagnose most problems. However, they need access to expert support to solve some of the more difficult problems and improve the quality of advice. Preliminary results show cases of poverty alleviation, reduction in pesticide abuse, increased harvests and other benefits. The plant health clinics in Bolivia enabled extension and research to reach more farmers with a timely low-cost service.     

Occurrence of fumonisins B1 and B2 in Portuguese maize and maize-based foods intended for human consumption

Fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) are mycotoxins mainly produced by Fusarium verticillioides and Fusarium proliferatum, which are field pathogens of maize. A survey was conducted on the incidences of FB₁ and FB₂ in both maize and derived products purchased in Portugal. The analytical method involved extraction with methanol-water, clean-up by immunoaffinity column and derivatization with naphthalene-2,3-dicarboxaldehyde. Determination was carried out by high-performance liquid chromatography (HPLC) with spectrofluorimetric detection, with liquid chromatography/mass spectrometry (LC/MS) confirmation. The presence of FB₁ and FB₂ was determined in 67 samples of maize and maize-based foods, such as flour, semolina, starch, sweet maize, cornflakes and other breakfast cereals, and snacks collected in 2005. FBs were found in 15 samples at concentrations ranging from 113 to 2026 µg kg^-1. Two of the samples showed higher contamination levels than the limits established by the European Commission Regulation. None of the samples contained levels of fumonisins that would lead to an exposure exceeding the tolerable daily intake (TDI).     

Organochlorine pesticide residues in European sardine, horse mackerel and Atlantic mackerel from Portugal.

This paper reports the results for the surveillance of nine organochlorine pesticides (HCH isomers (alpha, beta, e, gamma), p,p'-DDD, p,p'-DDT, p,p'-DDE, p,p'-DDD, HCB and aldrin) in muscle of three fish species, European pilchard (Sardina pilchardus), Atlantic horse mackerel (Trachurus trachurus) and Atlantic mackerel (Scomber scombrus). Analytical methodology included n-hexane extraction, clean-up with 2% deactivated Florisil, and quantification with gas chromatography-electron capture detection (GC-ECD). The highest mean concentrations were found for p,p'-DDT in sardine and mackerel at levels of 30.1 and 109.9 microg kg(-1), respectively, and for p,p'-DDD in horse mackerel at 51.9 microg kg(-1). Three species had higher levels for S-DDT than S-HCH. The estimated daily intake of organochlorine pesticides in the three species showed that in sardine, the highest EDIs were found for aldrin, at 1.8 ng kg(-1) bw day(-1), which represents 1.8% of the acceptable daily intake (ADI), and for ss-HCH, at 4.0 ng kg(-1) bw day(-1), representing 0.4% of ADI. Lowest values were found for Atlantic mackerel. Statistical analysis to determine the differences in mean concentrations of pesticides between species, and any correlation between groups of residues related with each one of the species, was undertaken.     

FLR technique: Exchange kinetics of ethanol/fluorescent dye with water in water-saturated cement paste examined by H- and H-NMR

A water-saturated cement paste (water-to-cement, w/c=1.0) confined in a solution of ethanol saturated with a fluorescent dye showed complete exchange of water after 2 days. The exchange rates of water and ethanol were independent of the presence of dye and determined to be 42×10⁻⁸ and 60×10⁻⁸ cm²/s, respectively. The exchange rate of dye was significantly smaller, by a factor of two to three. The exchange process resulted in a partitioning of the concentration of dye in ethanol within cement and bulk of (0.46+0.20). ¹H-NMR spectral analysis of the dye before and after exchange suggests the dye to be inert, i.e., it does not react with the cement paste. Furthermore, no indication of a reaction between ethanol and cement paste is observed.     

Development of coated ceramic components for the aluminum industry

In general, due to ceramic’s high hardness, which makes machining operations extremely difficult and very expensive, ceramic components are formed in shapes very close to the final ones. Considering this, a manufacturing process, based on a sol-gel reaction that allows rapid production of ceramic components in the final shape with a low level of shrinkage was developed. Although the ceramics obtained presented good behavior in short-term contact with molten aluminum alloys, there was no guarantee that the components produced would have adequate continuous resistance to chemical and erosive wear by liquid metals. To enhance their resistance, the ceramic parts were coated by flame spray. Different powders and conditions were used to determine the degree of coating adhesion to the substrate. The coated specimens were then submerged in a molten aluminum bath, at different temperatures and time settings, to evaluate the interaction between the ceramic components and the molten aluminum alloys.     

Experimental Determination of the Liquidus in the High-Basicity Region in the Al2O3(25?mass?pct)-CaO-MgO-SiO2 and Al2O3(35?mass?pct)-CaO-MgO-SiO2 Systems

Liquidus in the Al₂O₃(25 mass pct)-CaO-MgO-SiO₂(<20 mass pct) and Al₂O₃(35 mass pct)-CaO-MgO-SiO₂(<20 mass pct) systems were determined experimentally in the high-CaO-containing region at 1873 K (1600 °C). For the Al₂O₃(35 mass pct)-CaO-MgO-SiO₂(<20 mass pct) system, liquidus data were also determined for 1773 K (1500 °C). The equilibrating and quenching technique with subsequent electron probe microanalyzer (EPMA) microanalysis were employed. Based on the data, liquidus lines were constructed for the 25 and 35 mass pct alumina planes at silica contents generally below 20 mass pct. The current results showed a slightly lower solubility of CaO and a higher solubility of MgO at 1873 K (1600 °C) for the 25 mass pct Al₂O₃ section compared with the existing phase diagram. At 1773 K (1500 °C), the result showed a slightly lower solubility of both CaO and MgO in the 35 mass pct Al₂O₃ section compared with the existing phase diagram. In addition, the activities of MgO, CaO, and Al₂O₃ were estimated at 1773 K and 1873 K (1500 °C and 1600 °C) using the phase diagram information.     

Solidification of PCM around a curved tube

This paper presents the results of an experimental and numerical investigation on the solidification of PCM around a curved cold tube to determine the effects of the Dean number, cooling fluid flow rate and its temperature on the interface velocity, the time for complete solidification and the solidified mass. To formulate the solidification process around a curved tube a conduction model was used together with the immobilization technique and the Landau transform. The energy equation and the associated boundary conditions were discretized by the finite control volumes method. The computational program was optimized by numerical experiments and the optimized form was used to validate the model. Comparisons of the numerical predictions and experiments to investigate the effects the Dean number on the solidified mass showed agreement within 1% while the interface velocity and the time for complete solidification showed agreements of about 8% and less than 6%, respectively. The effects of the flow rate of the working fluid could be predicted within less than 8% for the solidified mass and to less than 4% for both the interface velocity and the time for complete solidification. The effects of the temperature of the working fluid are predictable to within less than 8% for the time for complete solidification and the interface velocity.     

Osthol Ameliorates Kidney Damage and Metabolic Syndrome Induced by a High-Fat/High-Sugar Diet

Excessive intake of fructose results in metabolic syndrome (MS) and kidney damage, partly mediated by its metabolism by fructokinase-C or ketohexokinase-C (KHK-C). Osthol has antioxidant properties, is capable of regulating adipogenesis, and inhibits KHK-C activity. Here, we examined the potential protective role of osthol in the development of kidney disease induced by a Western (high-fat/high-sugar) diet. Control rats fed with a high-fat/high-sugar diet were compared with two groups that also received two different doses of osthol (30 mg/kg/d or 40 mg/kg/d body weight BW). A fourth group served as a normal control and received regular chow. At the end of the follow-up, kidney function, metabolic markers, oxidative stress, and lipogenic enzymes were evaluated. The Western diet induced MS (hypertension, hyperglycemia, hypertriglyceridemia, obesity, hyperuricemia), a fall in the glomerular filtration rate, renal tubular damage, and increased oxidative stress in the kidney cortex, with increased expression of lipogenic enzymes and increased kidney KHK expression. Osthol treatment prevented the development of MS and ameliorated kidney damage by inhibiting KHK activity, preventing oxidative stress via nuclear factor erythroid 2-related factor (Nrf2) activation, and reducing renal lipotoxicity. These data suggest that the nutraceutical osthol might be an ancillary therapy to slow the progression of MS and kidney damage induced by a Western diet.