铝合金在NaCl溶液中的电化学腐蚀行为

采用极化曲线法和交流阻抗法,分析了ZL102和LF6铝合金在不同pH的3%NaCl溶液中的腐蚀特性,并用金相显微镜观察了铝合金的微观组织。结果表明,2种铝合金的自腐蚀电位都随着pH的升高变得愈负;除pH=9.5的情形之外,ZL102铝合金的腐蚀速率均小于LF6铝合金;LF6铝合金结构的不均匀性与其加入的合金化元素是导致其耐蚀性能较ZL102铝合金差的主要原因。     

Microbial safety control of compost material with cow dung by heat treatment

Various kinds of pathogenic bacteria derived from the intestinal tract of animals exist in compost material like cow dung.In order to sterilize the pathogenic bacteria completely in compost material,the cow dung was put into a heat treatment machine in pilot plan, and harmless condition in short time was examined.The results indicated,pathogenic indicator bacteria such as coliform bacteria, fecal coliform,Escherichia coli and salmonella were all 10~6 cfu/g dw at the beginning,died rapidly when cow dung temperature rose to above 50℃,and not detected at 54-68℃for 6-24 h heat treatment.Coliform bacteria and salmonella in heated cow dung were not detected by re-growth culture and enrichment culture examination.Moreover,it was hardly influenced on the fermentation ability of composting microbe,organic decomposition bacteria.During heat treatment,the mesophile decreased rapidly and the thermophile stabilized or increased,and the most of composting microbe were bacillus in cow dung by fluorescence microscope,this indicated that bacillus was dominator and composting microbe in composting process.     

Experimental hazardous risk investigation of energetic styphnic acid analytical reagent in calorimetric analysis

Analytical reagents identify and manage metal pollution, a major environmental issue. Regrettably, these compounds' safety concerns, especially when heated, have been neglected. This research examines the thermal hazard of the extremely reactive analytical reagent styphnic acid. Differential scanning calorimetry, thermogravimetric analysis, and accelerating rate calorimetry examined styphnic acid's thermodynamics. Thermogravimetric analysis showed weight loss reactions starting at 127 °C and peaking at 208 °C. Differential scanning calorimetry showed an endothermic peak at 176 °C. The accelerating rate calorimetry test showed that styphnic acid self-accelerates at 237 °C after 196.5 °C. Kissinger, Ozawa-Flynn-Wall, and Kissinger-Akahira-Sunose thermokinetic models calculated apparent activation energy from 131.677 to 155.718 kJ/mol. A nonlinear regression analysis showed that styphnic acid undergoes a two-step autocatalytic reaction during heat degradation. Thermal safety was assessed by measuring time to conversion limit, maximum rate, total energy release, self-accelerating decomposition temperature, and adiabatic temperature rise. Styphnic acid is less stable at higher temperatures and its thermal hazards depend on heating rate. The computed SADT was 109.04 °C, with alarm and control temperatures of 104.04 and 99.04 °C, respectively. The risk matrix analysis based on T_ad and TMR_ad suggests reducing thermal instability. This study on styphnic acid's thermal risks and safe storage and transit during analytical applications is beneficial.