Experimental study and prediction of liquid nitrogen pool evaporation process on concrete surface

The vaporization rate of pool boiling process of a liquid nitrogen spilled on concrete surface was investigated by a visual experiment platform. The boiling curve for liquid nitrogen on concrete cooling process was obtained. The shapes of bubbles in three typical boiling regimes were observed. Based on the experimental results, the coefficients of the empirical formulas for nuclear boiling and film boiling are modified, and the empirical formulas for boiling of liquid nitrogen-concrete surfaces are obtained. Combined with the calculation formula of the non-steady-state semi-infinite one-dimensional heat conduction temperature, a coupled calculation model for the heat transfer and vaporization process of liquid pool on the liquid nitrogen-concrete surface is proposed. Application of this model can better predict the quality of liquid nitrogen vaporization.     

Bacterial inactivation,DNA damage,and faster ATP degradation induced by ultraviolet disinfection

• Long amplicon is more effective to test DNA damage induced by UV. • ATP in bacteria does not degrade instantly but does eventually after UV exposure. • After medium pressure UV exposure, ATP degraded faster. The efficacy of ultraviolet (UV) disinfection has been validated in numerous studies by using culture-based methods. However, the discovery of viable but non-culturable bacteria has necessitated the investigation of UV disinfection based on bacterial viability parameters. We used quantitative polymerase chain reaction (qPCR) to investigate DNA damage and evaluated adenosine triphosphate (ATP) to indicate bacterial viability. The results of qPCR effectively showed the DNA damage induced by UV when using longer gene amplicons, in that sufficiently long amplicons of both 16S and gadA indicated that the UV induced DNA damages. The copy concentrations of the long amplicons of 16S and gadA decreased by 2.38 log/mL and 1.88 log/mL, respectively, after exposure to 40 mJ/cm² low-pressure UV. After UV exposure, the ATP level in the bacteria did not decrease instantly. Instead it decreased gradually at a rate that was positively related to the UV fluence. For low-pressure UV, this rate of decrease was slow, but for medium pressure UV, this rate of decrease was relatively high when the UV fluence reached 40 mJ/cm². At the same UV fluence, the ATP level in the bacteria decreased at a faster rate after exposure to medium-pressure UV.     

IEC 61215标准中紫外试验的解读

本文详细解读了IEC61215:2005标准中的紫外预处理试验。介绍了材料耐候性老化测试原理,包括户外老化及紫外光加速老化测试原理,从光谱的定义、辐照度的设定、温度及湿度控制等几个方面对IEC61215:2005标准中的紫外试验进行分析。最后指出QUV运行该标准时的参数设定。     

工业总排放水中Cr~(6+)含量测量不确定度的评定

采用分光光度法对工业总排放水中Cr6+进行不确定度评定,充分考虑测量重复性、标准溶液的配制、标准曲线的制备等因素对测量的影响,测得Cr6+的合成标准不确定度为0.023mg/L。     

建立数学模型分析UV-Fenton对金属切削液废水的降解

采用UV/Fenton技术处理金属切削液废水,并通过正交实验和单因素实验得到了最佳工作条件为:pH=2.5,H2O2(浓度30%)投加量=127.5 mL/L,Fe2+投加量=24.8 mmol/L,总反应时间=3 h,投加次数6次,此条件下金属切削液废水COD去除率达到95%。最后,通过正交实验数据和单因素模型方程利用1st Opt进行多元非线性拟合建立UV/Fen-ton对金属切削液废水COD降解率的数学模型方程,然后进行分析讨论。     

Stakeholder participation in sustainability assessment of non-wicked problems: The case of a future seaweed industry in Sweden

Acceptance by, and cooperation with relevant stakeholders in developing new sustainability initiatives when they are generally perceived as positive, is one of the keys for successful implementation of such new sustainability initiatives later on. It is remarkable, however, that ample literature exists about involving stakeholders in research projects focusing on problems with diverging views (controversy) around facts and values (wicked problems), but there is very little literature addressing whether and how to involve relevant stakeholders in case of initiatives where diverging norms and values do not play a (substantial) role, like in sustainability assessment for a future seaweed industry. This perspectives paper addresses that gap, and explores how to design such sustainability assessment, illustrated by how stakeholder interaction influenced the assessment and its results for a future seaweed industry in Sweden, followed by a discussion whether and how a similar approach may benefit sustainability assessment of other non-wicked sustainability initiatives.     

汽油降解菌的分离及降解研究

从泄漏污染的加油站土壤中筛选出对汽油具有较强降解能力的菌株,研究该菌株最适宜的生长条件,探讨紫外线诱导及投加表面活性剂等强化手段对该菌株降解汽油的影响.结果表明:①通过富集培养的方法分离得到的菌株Q18,经形态特征及生理生化特征鉴定,初步确定其为红球菌(Rhodococcus sp.).②菌株Q18在培养液中适宜生长的温度,pH和底物质量浓度分别为35 ℃,6.0和1 000 mg/L.③通过紫外线照射诱变后的菌株降解能力强于原始菌株,且15 W紫外灯对菌株的诱变效果优于30 W;氯化锂单独诱变效果不明显;经紫外灯照射和氯化锂复合诱变的菌株QY4对汽油的降解率达到了52.2%,在所有诱变菌中最高,效果最显著. ④表面活性剂能增强汽油的生物可利用性,强化菌株Q18对汽油的降解,但阴离子和非离子的混合表面活性剂SDS+TX-100和SDS+TW-80比单一表面活性剂更能有效提高菌株Q18对汽油的降解率.      

Pilot plant study on ozonation and biological activated carbon process for drinking water treatment

A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process （O3-BAC） and granular activated carbon process （GAC） were evaluated based on the following parameters： CODMn, UV254, total organic carbon （TOC）, assimilable organic carbon （AOC） and biodegradable dissolved organic carbon （BDOC）. In this test, the average removal rates of CODMn, UV254 and TOC in O3-BAC were 18.2%, 9.0% and 10.2% higher on （AOC） than in GAC, respectively. Ozonation increased 19.3-57.6 μg Acetate-C/L in AOC-P17, 45.6-130.6 μg Acetate-C/L in AOC-NOX and 0.1-0.5 mg/L in BDOC with ozone doses of 2 8 mg/L. The optimum ozone dose for maximum AOC formation was 3 mgO3/L. BAC filtration was effective process to improve biostability.     

上海老港填埋垃圾场渗滤液COD与UVA的相互关系

本实验研究对象为上海老港填埋场1991年填埋单元渗滤液和各处理工艺出水渗滤液,水样经过不同孔径膜微滤和超滤后,比较了各自COD值和UVA值之间的相关性．结果表明,水样COD浓度愈低,与其对应的UVA相关性愈好．由于有机物的组成不同,对应的特征吸收范围存在差别,因此,不同渗滤液的UVA与COD的关系也不同．渗滤液中的胶体物质对COD值有贡献,微滤和超滤系统使渗滤液中的胶体物质被截留,COD值减小,测定得到对应的UVA值也相应减小．     

太阳紫外线(UV)辐射对植物的影响

本文就同温层臭氧出现部分空洞引发的太阳紫外线(UV)辐射变化及其对植物生长、植物次生化学特性和植物生殖生长影响方面最近研究的进展情况以及取得的一些结果加以综合评述。