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71.
A number of microorganisms were isolated from sewage. Biochemical Oxygen Demand (BOD-5 day) analysis was carried out by individual pure cultures. The cultures giving higher or equal BOD values as compared to reference GGA solution were selected for the formulation of a defined mixed microbial consortium. This microbial consortium was co-immobilized on calcium-alginate beads. Four synthetic and six industrial samples were tested for BOD by using immobilized beads as well as sewage as source of seeding materials. BOD values obtained with beads for all the synthetic as well as industrial samples were fairly comparable with those obtained with sewage. Reusability of prepared microbial beads was also checked with different synthetic and industrial samples and was compared with reference GGA solution. The same microbial beads can be reused three times for different BOD-5 day estimations. It is recommended that immobilized microbial beads can be used as a ready-to-use seeding material for BOD analysis.  相似文献   
72.
确定压力容器安全系数原则   总被引:2,自引:0,他引:2  
压力容器安全系数与材料参数紧密相关,确定材料许用应力值时,需要同时考虑材料抗拉强度和屈服强度更为合理;奥氏体不锈钢材料具有非常好的应变强化能力和韧性,为充分发挥奥氏体不锈钢材料优良性能,选取奥氏体不锈钢材料许用应力值时,需要特殊考虑。压力容器安全系数的选取建立在经验基础上,在保障压力容器安全性前提条件下,为节省材料和降低成本,随着理论研究深入和科学实验的进步,压力容器安全系数有所降低,这是科学设计和实用成功经验结合的结果。  相似文献   
73.
本文介绍了炭催化剂吸附剂标准物质的研制过程。对标准物质的制备技术、均匀性检验、稳定性考察及定值和不确定度进行了逐项分析。采用活性炭浸渍、煅烧技术制得炭催化剂吸附剂标准物质。试验结果表明,该标准物质定值结果准确,均匀性、稳定性良好。铜含量的标准值为11.06%,扩展不确定度为0.13%。  相似文献   
74.
The objective of this study was to determine the best performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) based on the use of four different bed materials as support for biomass immobilization. The bed materials utilized were polyurethane foam (PU), vegetal carbon (VC), synthetic pumice (SP), and recycled low-density polyethylene (PE). The AnSBBR, with a total volume of 7.2L, was operated in 8-h batch cycles over 10 months, and fed with domestic sewage with an average influent chemical oxygen demand (COD) of 358+/-110mg/L. The average effluent COD values were 121+/-31, 208+/-54, 233+/-52, and 227+/-51mg/L, for PU, VC, SP, and PE, respectively. A modified first-order kinetic model was adjusted to temporal profiles of COD during a batch cycle, and the apparent kinetic constants were 0.52+/-0.05, 0.37+/-0.05, 0.80+/-0.04, and 0.30+/-0.02h(-1) for PU, VC, SP, and PE, respectively. Specific substrate utilization rates of 1.08, 0.11, and 0.86mg COD/mgVS day were obtained for PU, VC, and PE, respectively. Although SP yielded the highest kinetic coefficient, PU was considered the best support, since SP presented loss of chemical constituents during the reactor's operational phase. In addition, findings on the microbial community were associated with the reactor's performance data. Although PE did not show a satisfactory performance, an interesting microbial diversity was found on its surface. Based on the morphology and denaturing gradient gel electrophoresis (DGGE) results, PE showed the best capacity for promoting the attachment of methanogenic organisms, and is therefore a material that merits further analysis. PU was considered the most suitable material showing the best performance in terms of efficiency of solids and COD removal.  相似文献   
75.
防洪物资储备决策方法初探   总被引:2,自引:1,他引:1  
姚令侃  汤家发  杨明 《灾害学》2001,16(1):29-34
根据防洪抢险物资储备属于一种信息不全型决策问题的特点,本文提出了一种用于确定每年防灾物资准备量概率排序决策模型,并以孙不河流泥石流灾害预报火灾决策为例进行说明。  相似文献   
76.
某钢企大型低位料仓为汽车卸料,料仓厂房内空高,跨度大,料仓上部贯通,物料落差大,卸料中产生大量粉尘,环境污染问题典型突出。通过对低位料仓汽车卸料产尘特性分析,采取加强生产管理、组织汽车有序卸料、料仓厂房有效密闭、合理设计捕尘方式和布袋除尘系统等措施,能够有效地控制粉尘污染。除尘系统具有投资及运行费用少,除尘效果明显的优点。  相似文献   
77.
The objective of this paper is to discuss the main barriers for modelling and integrating the environmental performances in the automotive concept design. Incorporating environmental assessment in the early design phase of a vehicle component is known as an important challenge that car makers need to face in order to develop more sustainable design solutions; in this regard, the Life Cycle Assessment is the most widespread methodology for the environmental assessment and comparison of alternatives. The present work illustrates the combination of such methodology with the traditional design procedure at two different levels of the component design phase, material choice and concept design. In particular, the potential benefits originated by a lightweight solution for the automotive component Throttle Body are evaluated by considering environmental and technical implications at the same level. The case study shows that a multi-disciplinary approach for design effectively allows the integration of the environmental issue in the company’s established procedures. However, interpretation of results is still a challenging aspect due to the inevitable contradicting elements which should not discourage to develop comprehensive sustainability assessment within the early design stage.  相似文献   
78.
The building sector has been regarded as a potential sector where there is large capacity to reduce the climate change effect. This study has proposed solutions to mitigate environmental impacts and achieve low CO2 emission from residential sector. Therefore, full life cycle assessment (LCA) has been run to assess the CO2 emission and its effect on the atmosphere and climate change. Based on the result, timber scheme is the best choice due to releasing less CO2 emissions to the atmosphere. However, house builders in Malaysia have almost completely neglected timber as a building material, with timber use as building components reduced to 5%. In this study, LCA Software was used to assess CO2 emissions from different wall construction. The alternative building scheme has been made by reinforce steel stud, wooden beam and timber wall (S8) to improve the scheme deficiency while releasing less CO2 emissions compared to other schemes. Therefore, S8 has a decreased CO2 effect by 85% less than precast concrete frame and 90% less than brick over their lifetime. (S8) increased the load bearing compared to conventional timber beam. Thus, new scheme S8 could be replaced by current scheme and promote more adjustable scheme for Malaysian housing.  相似文献   
79.
考查了自制疏水性硅胶吸附材料AGS在加油站模拟油气回收装置及某油库现场油气回收装置的应用效果,并与常用的柱状活性炭进行了比较。实验结果表明:与活柱状性炭相比,AGS对油气的吸附速率和吸附量较小,但是油气脱附效果更好;将二者混合得到的吸附材料同时具备二者的优点,既具有较高的油气吸附量又具有良好的脱附性能,使油气回收装置具有更大的油气吸附量和更好的回收效果。  相似文献   
80.
释氧材料经济有效的释氧是地下水原位生物修复的关键因素。实验通过在释氧材料中加入膨润土、磷酸二氢钾和硫酸铵等,改进释氧材料的性能。柱实验结果显示,该释氧材料释氧速率缓慢,释氧时间长,可以使溶液中DO长期保持在5 mg/L以上;另外,释氧材料中添加的缓冲剂及天然含水层介质对pH值有较好的缓冲作用,可以使pH值达到后续生物修复的要求。  相似文献   
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