Defining Yield from Bender Element Measurements in Triaxial Stress Probe Experiments

This paper describes the elastic response of a block sample of compressible Chicago glacial clay under a variety of stresses and its relationship with the deformation characteristics at relatively large strains. The elastic shear stiffness was obtained from bender element tests during consolidation and shearing in drained triaxial stress probe tests. An empirical correlation was established based on the elastic shear stiffness in a preyield condition. By comparing the empirical correlation with the measured elastic shear stiffness in the stress region during probing, the changes of elastic shear stiffness were investigated. The departure of elastic shear stiffness from values computed by the empirical relation based on K0 loading directly relates to the yielding characteristics of the clay. The large-scale change of soil structure at yielding alters the well-established relationship between the elastic shear stiffness and stresses in the preyield condition. The mechanical yielding response of clays can be detected based on the systematic analysis of the elastic shear wave velocities.     

泌乳月份及部分乳成分与牛乳中体细胞数关系的相关性研究

本研究利用陕西省西安市草滩牛场第五奶牛场62头泌乳牛2003年8个月的DHI记录资料,对泌乳月份及部分乳成分与牛乳中体细胞数的关系进行了研究.结果表明,体细胞数与日产奶量,日产奶量与乳蛋白率、乳脂率呈极显著的负相关(P＜0.01),体细胞数与乳蛋白率与乳脂率之间无显著相关关系(P＞0.05),乳蛋白率与乳脂率呈极显著的正相关(P＜0.01).5、7和10月份样品平均体细胞数较高,分别为789×103mL-1,696×103mL-1、1031×103mL-1,3月份样品平均体细胞数最低为390×103mL-1.     

单根辐射管集水模型的研究

本文通过对影响单根辐射管集水因素的分析,探讨了集取河床渗透水的单根辐射管集水模型,并用模拟试验确定了模型参数。结果表明:模拟试验值、工程实例实测值与集水模型计算值具有一致性。     

Methods for phosphate addition in heavy salted cod (Gadus morhua L.)

Headed and gutted fresh or frozen and thawed cod (Gadus morhua L.) from the same net catch were hand filleted post rigor before carrying out small-scale salting trials. Fillets were heavy salted using three different methods introducing phosphate during injection, brining, or during pickle salting. For all salting methods, treatment with 0, 4.5, 9 or 18 g/L of the pyro and tri polyphosphate blend Carnal 2110 was carried out. Quality and chemical parameters were analyzed after 5 weeks and 6 ± 1 months of chilled storage of heavy salted fillets.     

中能^12C重离子在Fe等厚靶上核反应的中子产额和能谱

本文调研了由测量和核内级联-蒸发模型理论计算得到的中能区重离子核反应中子发射微分截面数据,并依据这些结果计算给出了单核能为58.3和100MeV 的~(12)C 离子轰击~(56)Fe 厚靶产生的次级中子能谱、角分布和总产额。同时对现有数据做了较为细致的分析,为重离子的防护提供了一些基础资料。     

Univer Project. A grid connected photovoltaic system of at Jaén University. Overview and performance analysis

Nowadays, grid connected photovoltaic (PV) systems are very popular in industrialized countries and can even be considered as the most promising PV application. The integration of these systems into urban buildings offers a large potential for cost reduction and can further increase the overall value of urban architecture. According to available statistics, by the end of 2002, more than 1.3 GWp of PV power was installed in industrialized countries world wide, which represents 70–85% of the total world capacity [J. Ohno, Progress in Photovoltaics: Research and Applications (2001) 471. [1]]. During recent years, a great number of European projects in the PV sector have been carried out in Spain. The Univer Project—UNIversidad VERde—is one of these European projects. It consists of four grid connected PV systems of fully integrated into the Jaén University buildings, in order to provide the University Campus with more than 8% of its electricity needs, i.e. 210 MWh/year.The aim of this paper is to present a general overview of the Univer Project and the performance analysis of its PV systems during their first phase of operation.     

Effect of extraction conditions on the yield and purity of ulvan extracted from Ulva lactuca

A study of the influence of extraction conditions (pH: 1.5 and 2; temperature: 80 °C and 90 °C; extraction time: 1–3 h), on the yield, chemical composition and purity of the sulphated cell wall polysaccharides ulvan, extracted from the green seaweed Ulva lactuca and precipitated by alcohol is carried out. The alcohol precipitate yields varied from 21.68% to 32.67% (%dw/dw) depending on the pH. At pH 2, the alcohol precipitate yields and the uronic acid recovery from extract juice are higher than those obtained at pH 1.5. Other compounds than ulvan such as cellulose, hemicellulose, proteins and ash are solubilized from the cell walls of Ulva lactuca at both pH, and they are precipitated with alcohol. The alcohol precipitate obtained from different extraction conditions has high uronic acid (20.37%–23.60%) and neutral sugar content (20.09%–29.12%), especially when the conditions (pH, temperature) are drastic. It contains rhamnose (13.35%–15.59%), glucose (2.90%–10.97%), and xylose (2.36%–2.73%). A decrease in the molecular weight of ulvan was observed at acid pH, and for long extraction times. The presence of proteins (1.94%–2.32%) and inorganic material (33.36%–47.15%) in alcohol precipitate prove the lower purity of ulvan extracted and shows that ulvan precipitation with ethanol is not specific.     

热缩聚工艺条件对中间相微球形成的影响

以煤焦油沥青为原料采用常压热缩聚工艺制备中间相沥青微球。考察了热缩聚温度和停留时间对中间相沥青收率、微球收率及形态的影响。发现在同一热缩聚温度下停留时间的延长，虽使中间相沥青的收率降低，但微球收率却相应提高，小球直径逐渐增大；提高热缩聚反应温度使微球更易长大，直到最终融并。通过控制热缩聚条件可以得到尺寸各异的中间相沥青微球。采用两步热溶抽提法可很好地将沥青微球从母液中提取出来     

Responses of clonal tea to location of production and plucking intervals

Tea is cultivated in diverse environments causing yield and quality differences in its beverages. To maximise yields and quality, agronomic practices should be optimised. But agronomic recommendations are uniform in different environments in Kenya despite variations in the growth factors responsible for changes in yields and quality. Plucking is labour intensive and a costly agronomic input in tea production. Trials were conducted for ten years in five tea growing regions in Kenya to assess yields and quality responses of clone BBK 35 tea to location of production and harvesting intervals. There were different (P ? 0.05) yields in the various locations, with significant (P ? 0.05) interaction effects between locations and harvesting intervals. Yields declined in three out of five regions but increased in one location with longer plucking intervals. Yields in a geographical area of production can not be used to estimate its expected yields in other tea growing areas. Black tea theaflavins varied significantly (P ? 0.05) with geographical area of production, but other plain tea quality parameters did not vary with location. It is therefore possible to make similar black teas with similar plain tea quality parameters except theaflavins from all tea growing regions of Kenya. Tea quality improved with short plucking rounds. One way to maximise tea quality is through shortening harvesting intervals. It is necessary to establish optimal harvesting rounds in the different tea growing regions in Kenya to maximise yields and quality.     

Distinctive properties of high hydrogen producing extreme thermophiles, Caldicellulosiruptor saccharolyticus and Thermotoga elfii

Growth and hydrogen production by two extreme thermophiles during sugar fermentation was investigated. In cultures of Caldicellulosiruptor saccharolyticus grown on sucrose and Thermotoga elfii grown on glucose stoichiometries of 3.3 mol of hydrogen and 2 mol of acetate per mol C₆-sugar unit were obtained. The hydrogen level was about 83% of the theoretical maximum. C. saccharolyticus and T. elfii reached maximum cell densities of 1.1×10⁹ and 0.8×10⁹ cells/ml, respectively, while their maximum hydrogen production rates were 11.7 and 5.1 mmol/g dry weight/h, respectively. For growth of C. saccharolyticus on sucrose, a biomass yield of 45.1 gDW/mol sucrose and a Y_ATP of 11.3–14.1 were calculated. Replacement of yeast extract by casamino acids, plus proline and vitamins in the medium of C. saccharolyticus resulted in similar yields of hydrogen production on sucrose, but diminished the rate by about 30%. Both yeast extract and tryptone were required by T. elfii, and appeared to function as sources of carbon, nitrogen and energy. In the absence of tryptone, T. elfii converted 26% of the glucose to another by-product, resulting in a lower yield of hydrogen. Growth of T. elfii ceased prior to glucose depletion, but the culture continued to ferment glucose to hydrogen and acetate until all glucose was consumed.