Characteristic properties of organosolv lignin/polylactide copolymers

A polylactide (PLA)/switchgrass organosolv lignin graft copolymer was synthesized via ring-opening polymerization. The resulting copolymer was characterized by size exclusion chromatography (SEC), differential scanning calorimetry, tensile testing, and hydrogen nuclear magnetic resonance spectroscopy. Phenolic hydroxyl content, percent lignin retained, and ultraviolet (UV) light transmission were investigated by UV light spectroscopy. Hydrolytic degradation and water vapor transmission rates were also investigated.It was found that the addition of organosolv switchgrass lignin to the polymer slowed the rate of degradation and water vapor transmission rate of the copolymer compared to the PLA homopolymer at varying temperatures. UV light transmission was also reduced with the addition of lignin.     

Nitrogen inputs in ground and surface waters in the middle Mulde catchment

As the EU Water Framework Directive (WFD) is translated into national legislation, the nitrogen (N) concentration in many rivers will have to be significantly reduced. In order to implement suitable measures, the relevant pathways and input quantities of nitrogen discharge have to be identified. For the Middle Mulde catchment in Saxony, Germany (2,700 km²), a pathway-related model is developed to quantify point and diffuse nitrogen discharges. Calculated N-input via point sources is 2,400 Mg entering the rivers in the study area every year. The main point input representing over 50% of the total is via municipal sewage treatment plants, followed by the industrial direct dischargers and the combined sewer overflows, amounting to approx. 20% (462 Mg and 444 Mg) each. The diffuse nitrogen discharges from the soil zone of the arable land amount to a total of 8,050 Mg per year in the 1980s and 2,815 Mg in the 1990s. The inputs via the groundwater flow make up the main proportion for the 1980s with 5,303 Mg, followed by 1,480 Mg from tile drainage and 1,267 Mg from direct runoff. In the 1990s the nitrogen discharge fell sharply with the considerable fall in the surpluses in the agricultural nitrogen balance after German reunification with 1,934 Mg (groundwater flow), 454 Mg (drainage runoff) and 410 Mg (direct runoff). Sensitivity analyses show that the parameter “total atmospheric deposition” represents the highest uncertainties, because of its uncertain quantification and the high sensitivity of the results to this variable.     

The Locus of Sulfate Sites on Sulfated Zirconia

The surface of sulfated zirconia was probed using X-ray photoelectron spectroscopy. It was observed that the entire inventory of sulfur could be completely removed by sputtering the surface using an argon beam. Calibration using a TiO₂(110) standard resulted in a surface concentration of 2.85 sulfur atoms/nm². This is in reasonable agreement with a value of 4.15 sulfur atoms/nm² based on sulfur analysis on the assumption that all of the sulfur was located at the surface. These results suggest that most, if not all, of the sulfur is near or at the surface. When charging was taken into account, we observed that the oxidation state of sulfur did not change following catalyst deactivation during the isomerization of n-butane. We also determined that the entire inventory of sulfur was present as SO₄ ^2-. These results reinforce previous studies suggesting that catalyst deactivation occurs as the result of carbon deposition and not a change in the oxidation state of sulfur.     

Changes in concentrations of dioxins and dioxin-like PCBs during processing of fish

Fish among meat and dairy products mainly contribute to the human exposition with dioxins and dioxin-like PCBs. Contaminant levels of fish are mainly determined in the edible part of the raw material. In Germany fish are not consumed raw but industrially processed to manifold products and cooked, fried or deep-fried in household. To study the influence of processing on the contaminant levels, changes of dioxins and partly of dioxin-like PCBs were followed during canning of herring fillets, hot smoking of mackerel fillets and Greenland halibut cutlets and during sugar salting of beheaded whole herring. The hot smoking process and sugar salting of herring led to an increase of the dioxin content in the edible part of the final product. The increase was related to the loss of water during processing whereas the fat and thus the lipophilic dioxins remained in the muscle meat. For sugar salting also changes of dioxin-like PCB levels were followed and the same effect was observed. Otherwise the production of canned herring fillets in tomato sauce led to a “dilution” of the dioxin content due to the addition of the sauce.     

Pigeons use item-specific and category-level information in the identification and categorization of human faces.

Three experiments examined the pigeon's ability to adapt to the specific tasks of identification and categorization of complex visual stimuli by attending to information at different levels of abstraction. In Experiment 1, pigeons were successively trained to discriminate first between pairs of human faces from the same sex and then between male and female faces. A final test revealed that the associations formed in the first training phase did not survive categorization training, indicating that the pigeons used item-specific information to discriminate faces of the same sex, but shifted their attention to category-level information for discriminating between the male and female categories. Two further experiments disproved alternative explanations. The results support the feature-learning account of open-ended categorization in animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

概率可靠性分析的实际应用

能源市场自由化的今天,对电网运营商来说降低成本和提高供电可靠性是相互矛盾的,解决起来比较棘手。为解决这一问题,在电网规划的过程中需要详细的信息,尤其是定量信息。适合于这项任务的工具就是概率可靠性分析,这种工具已成功运用了多年。文章对概率可靠性分析作了简短的描述,重点对体现其实际优势的几个应用示例进行了阐述。其结果证明概率可靠性分析已逐渐成为用户电网规划中不可或缺的组成部分。