Loblolly pine response to wet-weather harvesting on wet flats after 5 years

The timing of forestry operations relative to weather conditions is a consideration in applying Forestry Best Management Practices (BMPs). Harvesting during different seasons can result in degrees of soil disturbance, the distribution of logging debris, and potentially future stand productivity. The purpose of this study is to examine the response of loblolly pine (Pinus taeda L.) stands after wet- and dry-weather harvesting combined with three site preparation treatments. A 20 × 20 meter grid was established in fifteen 20-year-old, 3.3-ha loblolly pine plantations in South Carolina. A census of soil physical disturbance and slash distribution was made after harvesting. Growth was measured on 1/125th-ha plots at ages two and five. Dry-weather harvested (DWH) sites were 91% undisturbed, and 9% compressed. Wet-weather harvested (WWH) sites were 41% undisturbed, and 59% disturbed. WWH sites averaged 9% bare soil, while DWH sites averaged 16% with 1 kg m^-2 less logging residue; primarily in the form of heavy and light slash. At age five, the green-weight biomass of flat-planted DWH and WWH sites were 13.3 and 12.6 kg tree^-1 respectively, and on the bedded DWH and WWH sites were 18.6 and 22.8 kg tree^-1. Wet weather harvesting did not seem to adversely affect stand growth, and may have improved it. Due to a prolonged drought, bedding had a larger effect on WWH sites than DWH harvested sites. The effects of droughty conditions may be influencing treatment response on these highly productive sites; however, the long-term effects of harvesting on stand growth remain to be seen.     

城市重大事故应急演习方法研究---演习目标及其评价准则

应急演习是城市开展重大事故应急准备过程的主要任务之一,应急演习目标是检查演习效果,评价应急组织、人员应急准备状态和能力的指标.本文介绍了可供选择的十八项演习目标和各项目标的评价准则,同时介绍了分组选择演习目标的方法.     

纳米二氧化钛粉体的制备及对染料脱色的研究

以钛酸四丁酯为原料,采用溶胶-凝胶法、水热沉淀法、水解法制备了纳米二氧化钛粉体。经XRD对三种方法制得粉体进行了表征,讨论了三种方法的优缺点。以水解法制得二氧化钛粉对六种染料进行了脱色研究,结果表明其有良好的光催化脱色性能。     

Preparation and characterization of mixed hydroxy-Fe-Al pillared montmorillonite with large basal spacing

IntroductionMontmorilloniteisaclaymineralwithsubstantialisomorphicsubstitution .Mesoporouspillaredmontmorillonitecanbepreparedbyintroducinggallerytemplates ,suchasquaternaryammoniumcationandlongchainamine .Thusformedorgano montmorilloniteshaveimprovedcapa…     

Preparation and emission characteristics of ethanol-diesel fuel blends

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2% ) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.     

Ag/AgCl海洋电场探测电极研究进展

针对目前广泛应用于海洋电场传感器中的全固态粉压型Ag/AgCl电极对的极差稳定时间长,无法满足快速部署、实时探测这一要求,系统阐述了Ag/AgCl海洋电场探测电极的性能要求和制备工艺方法,对比了制备工艺的优缺点。综述了Ag/AgCl海洋电场探测电极的制备工艺优化以及改性方法,论述了近些年国内外关于Ag/AgCl电极改性的研究进展,并对Ag/AgCl海洋电场探测电极未来的研究与发展趋势进行了展望。     

工业废渣制备生物质裂解用催化剂载体及其性能

以赤泥和粉煤灰为原料,无水碳酸钠为造孔剂,制备了用于生物质裂解的催化剂载体。探讨了载体的焙烧工艺、最佳配方及其最高焙烧温度,并对按最佳工艺条件所制备的载体进行了性能测试。     

以硫铁矿烧渣为原料制备铁黄

用硫铁矿烧渣精制的FeSO4和N aOH为原料制备铁黄晶种,在二次氧化过程中用滴加氨水的方法制备铁黄颜料,考察了影响晶种质量及铁黄质量的诸多因素。实验得出的铁黄晶种制备的工艺条件为:温度25℃,碱比0.3,Fe2 初始浓度1m o l/L,通氧速率3.0L/(L.m in);二次氧化的工艺条件为:溶液pH3~4,晶种比25%,通氧速率4.0L/(L.m in)。经检测,用该法制备得到的铁黄产品质量达到中华人民共和国化工行业标准HG/T2249—91《氧化铁黄颜料》一级品标准。     

固体废物样品全溶解方法的比较研究

采用容器敞口酸消解、高压釜密闭酸消解及微波辅助酸消解3种溶样技术,对电镀污泥、尾矿渣、铬渣、砷钙渣、铅锌渣以及粉煤灰等固体废物试样的全溶解效果进行了对比试验,结果表明:敞口酸消解方法难以达到全溶解,繁琐耗时,易产生二次污染;高压釜密闭酸消解法溶解效果较好,但耗时和不安全;微波辅助酸消解法溶解效果最好,还具有快速方便,较少二次污染等特点。      

光活性二氧化钛膜的制备与应用

自８０年代末以来,光活性膜由于诱人的应用前景而成为环境领域的研究热点。本文主要介绍溶胶—凝胶法等制备二氧化钛膜的方法及其原理,并根据基于二氧化钛膜的光催化技术的特点简单地讨论了光活性二氧化钛膜的可能应用领域。