马特马克水库防洪发电效益

瑞士阿尔卑斯山区修建大坝的唯一目的是发电。但在近年发生几次大洪水后，研究了几种利用这些水库进行防洪的应对措施。本文采用概率法分析了马特马克水库特殊实例，对该工程弗来的防洪效益有了全面的认识。根据模型试验结果可选择最佳的防洪措施和最经济有效的防洪系统。     

西蒂坝溢洪道设计

西蒂坝于1975年投入运行，对大坝进行了坝体加高设计。随着大坝下游土地的占用，预计在百年一遇洪水时会发生大的破坏，因而，对坝体加高进行了重新设计，将增加一座闸控溢洪道和一个新增泄水底孔以更好地控制洪水，并将设置水库管理系统以防止百年一遇洪水时下游地区的洪水泛滥。     

Ruminal degradability and lysine bioavailability of soybean meals and effects on performance of dairy cows

Evaluations of 4 soybean meal (SBM) products were conducted in 3 experiments. The 4 products were 1) solvent SBM (SSBM), 2) SSBM treated with 0.05% baker's yeast and toasted at 100°C (YSBM), 3) expeller SBM (ESBM), and 4) lignosulfonate-treated SBM (LSBM). Multiparous Holstein cows (n = 32; 152 ± 63 d in milk; body weight = 708 ± 77 kg; producing 41 ± 7 kg/d of milk at the beginning of the study) were used in a 4 × 4 Latin square design with 28-d periods to investigate cow responsiveness to supplemental ruminally undegradable protein (RUP) from the SBM products. Dietary treatments were formulated by substituting all of the SSBM and part of the ground corn with YSBM, ESBM, or LSBM to yield isonitrogenous diets. Diets were formulated to provide adequate ruminally degradable protein, but deficient RUP and metabolizable protein supplies. No differences among dietary treatments were observed for dry matter intake, body weight gain, milk and component yields, or efficiency of milk production. The lack of response to changes in SBM source was likely due to an adequate RUP and metabolizable protein supply by all the diets. In situ ruminal degradations of YSBM and LSBM were slower than those of SSBM or ESBM; thus, RUP contents of YSBM and LSBM were greater than those of SSBM or ESBM. The RUP of all SBM products had similar small intestinal digestibility. Available Lys contents, estimated chemically or by using a chick growth assay, were less for YSBM and LSBM than for SSBM or ESBM, suggesting deleterious effects of processing on Lys availability in YSBM and LSBM.     

Effects of yeast and bran on phytate degradation and minerals in rice bread

ABSTRACT:  Rice bread is a potential alternative to wheat bread for gluten-sensitive individuals. Incorporation of rice bran into bread made from white rice flour adds flavor but also phytic acid, which can reduce the bioavailability of minerals. Breads with varied amounts of defatted bran and yeast were prepared to determine their effects on the phytate and mineral contents of the bread. A completely randomized factorial design was used with bran levels of 3.7%, 7.3%, and 10.5% of the dry ingredients and yeast levels of 1.6%, 3.2%, and 4.7%. Increasing the amount of bran decreased the phytate degradation from 42% at the lowest level of bran to 10% at the highest, and the amount of yeast had no significant effect. The bran contributed substantial amounts of magnesium, iron, and zinc. Breads with the lowest level of bran had phytate-to-zinc molar ratios between 5 and 10, which suggest medium zinc bioavailability. Rice bread is a tasty and nutritious food that is a good dietary source of minerals for people who cannot tolerate wheat bread.     

哥伦比亚188m高的米尔一级RCC坝

这座世界上最高的RCC坝以平均日浇筑量3000m3的速度在26个月内建成。本文介绍的许多设计特点证明该工程是现代RCC大坝施工的一个典范。     

气垫式调压室的土工设计

气垫式调压室是水电站中替代传统开敞式调压井的一种方案，自1973年开始，挪威就已采用该方法。业已证明，这种调压室能满足水力需求，是使隧洞系统的布置和电站选址具有很大自由度的经济实用的方案。防止漏气是气垫式调压室设计和施工过程中所要考虑的主要问题。本文阐述了如何有效地处理漏气和其它一些土工方面的问题。     

Tracer studies and hydraulic behaviour of planted and un-planted vertical-flow constructed wetlands

The aim of this research was to assess the hydraulic behaviour of three intermittently-fed vertical flow wetland units operated in parallel, designed for the treatment of raw wastewater generated in the city of Belo Horizonte, Brazil. The system was designed to serve 100 PE (-1 m2/PE). The first filter was planted with cattail (Typha latifolia), the second with Tifton-85 (Cynodon spp.) and the third was maintained without plants (control unit). NaCl tracer tests were conducted to determine the residence time distribution. The tests were done with water when the system was unused (clean media) and also after an 11-month operation period with wastewater (used media), using two different dosing regimes (lower and higher frequency). Results showed a strong tendency towards the hydraulic completely mixed regime. A great dispersion in the units and the presence of short circuiting and dead zones were observed. The unsaturated condition in a large volume of the filter, even during the draining stage, was confirmed for the three units. The dosing regime, the resting period duration, the age of the filter and the presence of plants were found to influence the hydraulic processes in the units.     

Identification of key constituents and structure of the extracellular polymeric substances excreted by Bacillus megaterium TF10 for their flocculation capacity

Extracellular polymeric substances (EPS), a complex high-molecular-weight mixture of polymers excreted by microorganisms and produced from cell lysis, may have a high bioflocculation activity. In this work, the EPS excreted from Bacillus megaterium TF10, which was isolated from a soil sample, were systematically characterized to give insights into the relationship between their specific constituents and structure with their flocculation capacity. The results of microscopic observation, zeta potential, and TF10 EPS structure analysis show that the bridging mechanism was mainly responsible for the flocculation of the TF10. The constituents with a large molecular weight (1037-2521 kDA) and functional groups had contributed to the flocculation. GC-MS and NMR analyses demonstrate that the polysaccharides had long chain composed of rhamnose as well as glucose and galactose with uronic acids, acetyl amino sugars, and proteins as the side chains. The proteins in TF10 had no flocculation ability because of their special secondary structure and molecular weight diffusion characters. The EPS from Bacillus megaterium TF10 were found to exhibit a high flocculation activity, and the polysaccharides in EPS, which have the structure of the long backbone with active side chains, were identified as the active constituents for the high flocculation activity.     

Body composition and energy metabolism at rest

Indicators of body composition determined by bioelectrical impedance analysis (total body water, extracellular water mass, intracellular water mass, skeletal muscle mass, soft lean mass, protein, mineral mass, fat mass) were compared with the resting metabolic rate values (RMR). Studies were conducted in adults of different occupations, gender, age, weight and height. In total, the survey involved 180 people, residents of Nizhny Novgorod (70 men and 110 women) aged 17 to 63 years. It was shown that the normalization of the RMR with the parameters of the bioelectrical impedance analysis reduced the scatter of individual values. Comparison of the normalization results allowed us to estimate the interconnection between the RMR and the body composition. It was obtained statistical formulas for the relation of the RMR with the bioelectrical impedance. The greatest effect was found with the normalization of lean mass, as well as intracellular and extracellular water masses. The smallest effect was detected with the normalization of body fat. We obtained statistical formulas for the relation of the RMR with the bioelectrical impedance parameters. The highest correlations were found between the RMR and the lean mass, muscle mass and total water mass, the lowest with the fat mass. Role of the metabolically active tissue in energy metabolism, including the role of the intracellular and extracellular water is discussed. The results confirm the importance of the metabolically active tissues in the formation of the value of the RMR. Identified dependencies and high correlation between the RMR and the bioelectrical impedance parameters allows us to use these as a fast and convenient method for the approximate estimation of the RMR.     

Factors associated with serum polybrominated diphenyl ether (PBDE) levels among school-age children in the CHAMACOS cohort

Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants historically used in textiles, furniture, and electronic products. Recent studies have documented widespread PBDE exposure to humans, with higher levels measured in children than adults. We analyzed 10 tri- to hepta-BDE congener levels in blood collected from 7-year old Mexican-American children living in an agriculture community in California (n = 272). The most frequently detected PBDE congeners in child serum were BDE-47, -99, -100, and -153, all of which were measured in >99% of the children. We used multiple linear regression models to examine associations between child total PBDE levels (ng/g lipid) and determinants of exposure. Factors positively associated with higher PBDE levels in the children were total PBDE levels in maternal serum during pregnancy, duration of exclusive breastfeeding, and having no safe places to play in their neighborhood. Child BMI was inversely associated with serum PBDE levels (regression p-values <0.05). Our findings confirm that exposure to the penta-BDE mixture is ongoing, and that Mexican-American children living in California may be experiencing higher PBDE exposure from their environment compared to children sampled from the general U.S. population. Additional research is needed to assess the health impacts of these exposures.