高压水射流计算机模拟可视化初探

在分析射流参数解析解的基础上,结合前人提出的有关经验公式,利用可视化软件工具和可视化图形工具,对高压水射流的射流结构和射流参数进行可视化模拟。阐明了模拟可视化的必要性和可行性,提出了可视化模拟在高压水射流技术研究上的几个可能的发展方向。     

论灾害救助实力

本文论述了当前我国灾害救助工作的宏观背景和主要矛盾,提出了新形势下灾害救助工作的出路在于改革传统的灾害救助体制,增强灾害救助实力,进而重点探讨了灾害救助实力的多元结构、运作原则和运行机制。     

GOALS IN WASTEWATER TREATMENT1

Within a few years all domestic wastewater effluents in the United States will be subjected to a minimum of a properly operated primary and secondary treatment process. This implies a very high degree of removal of the more readily biologically degradable material as measured by the BOD test. This practice will to a large degree negate the value of the BOD test as a pollution parameter. Organic carbon appears to be a more suitable means for determining the strength of a wastewater or for controlling the operation of physical and chemical treatment processes. Studies were conducted to determine the effect of time of passage on the ratio of organic carbon to BOD, COD and carbohydrate. The ratio was found to vary with both time and the state of the sample. The carbon content was reduced to a lesser degree than the other parameters. Organic carbon content appears to correlate better with COD than with BOD. The efficiency of a chemical precipitation process can be determined on the basis of organic carbon removal.     

Effects of mechanical fracturing and experimental trampling on Hawaiian corals

In situ trampling occurred under experimental conditions to quantify the differences in the responses to anthropogenic trampling in four dominant species of Hawaiian corals, Porites compressa, Porites lobata, Montipora capitata, and Pocillopora meandrina. Trampling was simulated daily for a period of nine days at which time further breakage was minimal. Forty treatment colonies produced 559 fragments. Trampling was followed by an 11-month recovery period. Coral colony and fragment mortality was low. All four species were highly tolerant of inflicted damage, suggesting that some species of corals can withstand limited pulse events that allow time for recovery. Growth rates following trampling were significantly lower in the treatment groups for three of the four species. This study demonstrated that very few trampling events can produce significant changes in growth even after a long recovery period. Survivorship of fragments is clearly size- and species-dependent in M. capitata and P. compressa. Smaller fragments (<5 cm) had higher mortality than larger fragments (>5 cm). High breakage rates for M. capitata and P. compressa are consistent with the nearshore, low-energy regions they inhabit—the same environment frequented by skin divers and waders. Mechanical tests were conducted to determine tensile and compressive strengths. Pocillopora meandrina exhibited the strongest skeletal strength, followed in decreasing order by Porites lobata, Porites compressa, and Montipora capitata. The skeletal strength obtained from the experiments correlate with the wave energy present in the environments in the regions they inhabit, suggesting that structural strength of corals is an adaptive response to hydraulic stress.     

多孔零件水射流清洗机研制

根据生产需要，我们研制了“水射流自动清洗机”，采用水射流技术与清洗剂相结合，完成工序间、装配前的机械零件（尤其带有小孔、盲孔等多孔零件）的清洗，取得了普通清洗方法难以达到的清洗效果。该机在国内同类型清洗机中，首先采用水射流技术，全部流程，由ＰＣ机控制，加上水循环处理系统，其清洗自动化程度高，清洗速度快，清洗液消耗少，在实际生产中取得了良好效果。     

高压容器旋转自紧方法研究

把超速旋转工艺引入高压容器自紧过程，提出旋转自紧方法，并对平面应变问题导出了厚壁圆管在旋转时的弹塑性及塑性极限的应力解和停转后的残余应力解，所得结果表明，由于残余应力的存在而导致了圆管弹性强度极限的提高，达到了自紧的效果。     

应用SSIM模型反演与评估二氧化硫污染面源

针对在缺少有效二氧化硫低空面源排放清单的情况下,应用SSIM(SourceStrengthInversedModel)模式对SO2低空面源源强的反演功能,完成了天津市蓝天工程改燃措施实施后二氧化硫相对量化改善效果的模拟评估,同时模拟了SO2面源源强改善前后的空间分布,取得了较理想的效果。该模式所解决的污染面源源强核查难点问题,在城市大气环境容量核定中具有通用指导作用。     

利用自养煤矸石砖技术治理铬渣初步研究

本研究通过焙烧试验 ,对利用自养煤矸石砖技术治理铬渣进行了初步研究。结果表明 ,在自养煤矸石砖的焙烧过程中 ,其中炭和自身热量能将铬渣中六价铬还原成 (三价铬 )。本研究确定了该铬渣治理方法工艺简单、成本低、解毒彻底、稳定性强 ,具有广泛的应用前景。     

机械处理废弃印刷线路板

分析了废弃印刷线路板的特点，介绍了机械处理的方法，及国外机械处理废弃印刷线路板的实践和进展。     

Carbon storage potential in natural fiber composites

The environmental performance of hemp based natural fiber mat thermoplastic (NMT) has been evaluated in this study by quantifying carbon storage potential and CO₂ emissions and comparing the results with commercially available glass fiber composites. Non-woven mats of hemp fiber and polypropylene matrix were used to make NMT samples by film-stacking method without using any binder aid. The results showed that hemp based NMT have compatible or even better strength properties as compared to conventional flax based thermoplastics. A value of 63 MPa for flexural strength is achieved at 64% fiber content by weight. Similarly, impact energy values (84–154 J/m) are also promising. The carbon sequestration and storage by hemp crop through photosynthesis is estimated by quantifying dry biomass of fibers based on one metric ton of NMT. A value of 325 kg carbon per metric ton of hemp based composite is estimated which can be stored by the product during its useful life. An extra 22% carbon storage can be achieved by increasing the compression ratio by 13% while maintaining same flexural strength. Further, net carbon sequestration by industrial hemp crop is estimated as 0.67 ton/h/year, which is compatible to all USA urban trees and very close to naturally, regenerated forests. A comparative life cycle analysis focused on non-renewable energy consumption of natural and glass fiber composites shows that a net saving of 50 000 MJ (3 ton CO₂ emissions) per ton of thermoplastic can be achieved by replacing 30% glass fiber reinforcement with 65% hemp fiber. It is further estimated that 3.07 million ton CO₂ emissions (4.3% of total USA industrial emissions) and 1.19 million m³ crude oil (1.0% of total Canadian oil consumption) can be saved by substituting 50% fiber glass plastics with natural fiber composites in North American auto applications. However, to compete with glass fiber effectively, further research is needed to improve natural fiber processing, interfacial bonding and control moisture sensitivity in longer run.