Preparation of phosphorus targets using the compound phosphorus nitride

Commercially available phosphorus nitride (P₃N₅) shows a high oxygen content. Nevertheless, this material is attractive for use as phosphorus targets in experiments where red phosphorus would disappear due to its high vapor pressure and where a metal partner in the phosphite must be excluded due to its high atomic number. Methods are described to produce phosphorus nitrite targets by vacuum evaporation condensation.     

Laboratory pull-out tests using bamboo and polymer geogrids including a case study

This study investigates the interaction between soil and geogrids by using both direct shear and pull-out tests and applied the results to a case study. A polymer geogrid and bamboo grids were used with clayey sand and weathered clay as backfill since these materials are readily available in Thailand. The results indicated that the interaction between soil and reinforcement consists of: (a) the adhesion between soil and reinforcement on the solid surface area of the geogrid; and (b) the bearing capacity of soil in front of all transverse members of the geogrids which behaved as a strip footing embedded in the soil. The proposed design procedure for pull-out resistance agreed fairly well with the laboratory pull-out test results. In addition, it was observed that bamboo grids have higher pull-out resistance per unit area than the polymer geogrids. Moreover, the cohesive fill proved to be quite effective when used with geogrid reinforcement. Finally, the proposed design procedure and test results were applied to a case study on an irrigation canal bank repaired by the Public Works Department of Thailand using cohesive backfill and Tensar SS2 geogrids resulting in much improved slope stability.     

Pyrolysis of Mississippi lignite in a fixed bed

The lignite deposits in Mississippi make up approximately 25 percent of the Gulf Coast deposit. To date, the limited number of studies on this lignite have chiefly been by Phillips Coal [1] and investigators in Mississippi [2,3]. This lignite, which is high in ash and moisture, was pyrolyzed in a 2.54 cm (1 in.) diameter fixed bed pyrolyzer under a helium atmosphere at temperatures ranging from 400°C to 950°C. The loss of volatile matter increased with increasing ultimate temperature producing weight losses 20–25% greater than the proximate analysis at 900°C. The yield of tar was found to decrease with temperature while volumetric gas production increased with the ultimate temperature. Hydrogen and carbon monoxide yields increased dramatically above 750°C. The maximum yield of gas was 375 ml/g daf lignite and was achieved at and above 815°C.     

Genome-Wide Identification,Expansion, and Evolution Analysis of Homeobox Gene Family Reveals TALE Genes Important for Secondary Cell Wall Biosynthesis in Moso Bamboo (Phyllostachys edulis)

The TALE gene family is a subfamily of the homeobox gene family and has been implicated in regulating plant secondary growth. However, reports about the evolutionary history and function of the TALE gene family in bamboo are limited. Here, the homeobox gene families of moso bamboo Olyra latifolia and Bonia amplexicaulis were identified and compared. Many duplication events and obvious expansions were found in the TALE family of woody bamboo. PhTALEs were found to have high syntenies with TALE genes in rice. Through gene co-expression analysis and quantitative real-time PCR analysis, the candidate PhTALEs were thought to be involved in regulating secondary cell wall development of moso bamboo during the fast-growing stage. Among these candidate PhTALEs, orthologs of OsKNAT7, OSH15, and SH5 in moso bamboo may regulate xylan synthesis by regulating the expression of IRX-like genes. These results suggested that PhTALEs may participate in the secondary cell wall deposition in internodes during the fast-growing stage of moso bamboo. The expansion of the TALE gene family may be implicated in the increased lignification of woody bamboo when divergent from herbaceous bamboos.     

File space utilization in database conversion

File space is an important type of resource needed during the process of converting data base from one form to another. Each file used in the conversion process has a size and life span. The life span of a file is measured from its creation time until the time it is no longer needed in the conversion process. The problem considered in this paper is to find a schedule for the different steps of the conversion process such that the sum of file costs is minimized. The cost of a file is defined as its life span times its size. The problem under consideration is NP-complete, and we therefore present an efficient algorithm for a special case, where the given precedence constraints are series parallel.     

蒸煮助剂对低用碱量硫酸盐法预处理毛竹竹屑的影响

毛竹竹屑经10%低用碱量 (以Na₂O计)、20%硫化度、160 ℃下保温1 h预处理,木质素脱除率达到62.35%,预处理物料酶水解48 h葡萄糖和木糖得率分别为56.04%和53.47%。研究了硼氢化钠、三聚磷酸钠、2-蒽醌磺酸钠3种蒸煮助剂对毛竹竹屑10%用碱量硫酸盐预处理的成分以及糖化效果影响,其中2-蒽醌磺酸钠影响最大。在10%用碱量和20%硫化度的预处理液中添加0.15%的2-蒽醌磺酸时,160 ℃下保温1 h的葡聚糖回收率和木质素脱除率分别为94.93%和68.55%,与空白对比分别提高5.45%和9.94%;预处理物料酶解48 h葡萄糖和木糖得率分别为62.88%和58.97%,与空白对比分别提高12.21%和10.29%。     

Regulation of Water Quality in Lake Michigan: Report of the Food Web Workshop

During the past 20 years, Lake Michigan has experienced substantial reduction in nutrient inputs, major changes in the biological community, and re-configuration of the pelagic food web. Alewife, the previously dominant zooplanktivore, has decreased to 10–20% of its former abundance, a new assemblage of zooplankton has become dominant, and summer water clarity has increased nearly three-fold in that time. This report summarizes an International Joint Commission (IJC)-sponsored Workshop on Food Web Interactions convened in Ann Arbor during 4–6 December 1985. In general, physical-chemical conditions are the major regulators of water quality during spring and fall periods. Food web effects are most manifest in offshore waters during the period of summer stratification. Discussion during the workshop led to insights regarding the causes of recent changes, their association with nutrient controls and/or food web interactions, and the likely dimensions for future effects.