Simulating dairy liquid waste management options as a nitrogen source for crops

Large scale dairy operations are common. In many cases the manure is deposited on a paved surface and then removed with a flushing system, after which the solids are separated, the liquid stored in ponds, and eventually the liquid applied on adjacent crop land. Management of liquid manure to maximize the fertilizer value and minimize water quality degradation requires knowledge of the interactive effects of mineralization of organic N (ON) to NH₄⁺, crop uptake of mineral N, and leaching of NO₃⁻ on a temporal basis. The purpose of the research was to use the ENVIRO-GRO model to simulate how the amount of applied N, timing of N application, ON mineralization rates, chemical form of N applied, and irrigation uniformity affected (1) yields of corn (Zea mays) in summer and a forage grass in winter in a Mediterranean climate and (2) the amount of NO₃⁻ leached below the root zone. This management practice is typical for dairies in the San Joaquin Valley of California. The simulations were conducted for a 10-year period. Steady state conditions, whereby an equivalent amount of N applied in the organic form will be mineralized in a given year, are achieved more rapidly for materials with high mineralization rates. Both timing and total quantity of N application are important in affecting crop yield and potential N leaching. Major conclusions from the simulations are as follows. Frequent low applications are preferred to less frequent higher applications. Increasing the amount of N application increased both the crop yield and the amount of NO₃⁻ leached. Increasing irrigation uniformity increased crop yields but had variable effects on the amount of NO₃⁻ leached. A winter forage crop following a summer corn crop effectively reduced the leaching of residual soil N following the corn crop.     

目前环境污染治理存在的问题及对策

本文论述了目前环境污染治理技术及其在应用中存在的问题。由于环境污染治理技术本身的局限性以及人们观念等原因 ,目前的环境污染治理存在一定的局限性 ,如何认识并克服它成为一个不容忽视的问题 ;并提出有实施污染治理过程中 ,必须用持续发展的理论进行指导 ,将污染物的污染防治战略转变为污染防止战略即“清洁生产”战略     

大型车车身覆盖件冲压成形特征分析及选材研究

为满足大型车身覆盖件冲压成形要求并实现钢板与零件的对路供应 ,必须在深入解析零件成形特征的基础上 ,确定高应变部位的成形敏感材料参数。在材料力学性能测试和成形极限分析的基础上 ,对侧围外板的冲压成形特征和成形敏感参数进行了分析。结果表明 :侧围外板零件高应变部位的变形方式为胀形 深拉延变形 ,n值和r值为影响侧围外板零件成形的主要材料敏感参数     

蔗糖厂自愿清洁生产审核实例

介绍了蔗糖厂自愿清洁生产审核中的审核重点、审核目标的确定，清洁生产方案的产生和筛选，以及清洁生产审核效果的统计。     

微生物絮凝剂的研究现状与发展趋势

介绍了近几年来国内外微生物絮凝剂的发展概况、分类及絮凝机理,指出了与传统絮凝剂相比较微生物絮凝剂在水处理中的优越性,分析了已使用的微生物絮凝剂在污水达标治理过程中存在的问题,并探讨了开发廉价、高效、可降解微生物絮凝剂的发展趋势和研究方向.     

声波吹灰器在300MW发电机组的应用

华电潍坊发电有限公司通过不断探索改造,利用成熟技术,解决了原蒸汽吹灰系统长期投用的问题,并发挥了较好的吹灰效果.吹灰器改造后的试验报告,验证了投用波吹灰器对提高锅炉效率和锅炉安全性能有明显作用,在同类型机组上具有较强的推广意义.     

大理生态旅游资源开发的思考与探析

生态旅游是一种符合可持续发展的旅游形式，可持续发展旅游业不仅保护环境，保护旅游资源，还为旅游业的后续开发提供条件。分析了大理生态旅游的现状及其存在的问题，提出了相应的对策措施。     

陶瓷微滤膜过滤黑液的清洗与再生

对无机陶瓷微滤膜过滤草桨黑液的膜清洗及再生的方法进行了研究。考察了物理和化学方法的再生效果、单种清洗剂的清洗效果、复合方法的清洗效果和效果的可重复性。结果表明物理冲洗、高温灼烧、单一的化学清洗剂清洗均可以提高陶瓷膜的再生通量；但是复合方法对陶瓷微滤膜的再生效果较好，其中按氢氧化钠溶液清洗、硝酸溶液清洗、次氯酸钠溶液清洗的实验步骤，膜的再生渗透通量高．且重复性强，可望在工业生产的在线清洗中应用。     

“赛力奇”的致突变性研究

选用Ａｍｅｓ试验、小鼠骨髓细胞微核实验和小鼠显性致死突变试验对新型食品添加剂“赛力奇”的致突变性进行了检验。结果表明：三项试验的结果均生。根据国家《食品安全性毒理学评价程序（试行）》的规定，认为“赛力奇”无致突变性。     

生命周期评价的应用,内涵与挑战

从环境问题与可持续发展出发，指出生命周期评价是在产品层次上实现可持续发展的一种理论评价工具，并探讨了生命周期评价的内涵，论述产品生命周是进行生命周期评价的客观依据，详细探讨应用生命周期评价存在的问题，指出进一步研究生命周期评价的方向。