流动系统内生物膜的形成及控制

应用辐射流动室（Ｒａｄｉｃａｌ Ｆｌｏｗ Ｃｈａｍｂｅｒ,ＲＦＣ）技术宣地研究水力剪切力对硝化细菌在聚苯乙烯（ＰＳ）载体表面固定的。发现水力剪切力直接影响硝化细菌的固定。当作用于ＰＳ表面的水力剪切力大于８．０Ｎ／ｍ＾２时,硝化细菌基本不能在ＰＳ表面险境着;水力剪切力小于８．０Ｎ／ｍ＾２时,硝化细菌的固定程度随剪切力的减小而加强,直至达到最大,实验表明辐射液动室技术为定量研究生物膜形成及控制与水力剪     

国外矿用应急救生舱技术现状

在南非、澳大利亚等矿业发达国家,应急避难室(救生舱)是一种重要的井下应急救援装备,用于在矿井事故发生后保护被困矿工,等待救援。本文对国外现有救生舱产品进行了深入的调研,对救生舱内氧气供应、有害气体去除、空气调节、环境监测、动力供应、附属装备等各主要系统的运行原理和技术指标进行了详细介绍,为分析国外救生舱技术研究现状和研发我国矿井救生舱产品提供参数依据和指导。     

美缝剂TVOC释放量与释放规律的测试与分析

提出了环境舱法测试美缝剂总挥发性有机化合物(TVOC)释放量的方法,对市场常见的美缝剂产品的TVOC进行了测试,并研究了美缝剂的TVOC释放规律和主要污染物.同时对美缝剂的甲醛释放量进行了测试.通过对16种环氧树脂美缝剂产品的数据分析显示,美缝剂产品的甲醛释放量风险较低;75%的产品在第7天的TVOC释放量可达到500μg·m^-3以下.但个别产品在28 d时仍有明显的VOC释放,显示其具有长期缓慢释放的特点.美缝剂释放的主要污染物为苯甲醛与苯甲醇,个别产品检出有甲苯和邻苯二甲酸酯类物质.     

动态平衡法测试气候舱回收率的方法研究

气候舱法凭借可靠的环境模拟特性和非破坏性,是目前国际与国内广泛采用的实验室检测方法,常用于检测木制品家具、建筑材料和汽车中的有害物质。本研究测定挥发性有机化合物组分的气候舱法回收率,发现持续注射甲苯3h后浓度才达到动态平衡,3h后的平均回收率为87.7%,证明动态平衡法适用于测定气候舱回收率的测定,同时证明了气候舱法测定VOC组分能够符合标准的要求。     

Geological emission of methane from the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China

A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and p...     

Fuel efficiency enhancement of modified diesel engine operated in dual fuel mode using renewable and sustainable fuels

ABSTRACT

Renewable and sustainable fuels for diesel engine applications provide energy protection, overseas exchange saving and address atmospheric and socio-economic concerns. This study presents the investigational work carried out on a single cylinder, four-stroke, direct injection diesel engine operated in dual fuel (DF) mode using renewable and sustainable fuels. In the first phase, a Y-shaped mixing chamber or venture was developed with varied angle facility for gas entry at 30°, 45° and 60°, respectively, to enable homogeneous air and gas mixing. Further effect of different gas and air mixture entry on the DF engine performance was studied. In the next phase of the work, hydrogen flow rate influence on the combustion and emission characteristics of a compression ignition (CI) engine operated in DF mode using diesel, neem oil methyl ester (NeOME) and producer gas has been investigated. During experimentation, hydrogen was mixed in different proportions varied from 3 to 12 l/min (lpm) in step of 3 lpm along with air-producer gas and the mixtures were directly inducted into engine cylinder during suction stroke. Experimental investigation showed that 45° Y-shaped mixing chamber resulted in improved performance with acceptable emission levels. Further, it is observed that investigation showed that at maximum operating conditions and hydrogen flow rate of 9 lpm, Diesel–producer gas and NeOME–producer gas combination showed increased thermal efficiency by 13.2% and 3.8%, respectively, compared to the DF operation without hydrogen addition. Further, it is noticed that hydrogen-enriched producer gas lowers the power derating by 5–10% and increases nitric oxide (NO_x) emissions. However, increased hydrogen addition beyond the 12 lpm leads to sever knocking.

Abbreviations: NeOME: Neem oil methyl ester; BTE: brake thermal efficiency; CI: compression ignition; ITE: indicated thermal efficiency; PG: producer gas; CA: crank angle; K: Kelvin; BP: brake power; IP: indicated power; H₂: hydrogen; HC: unburnt hydrocarbon; CO: carbon dioxide; CO₂: carbon dioxide; NO_x: nitric oxide; HRR: heat release rate; %: percentage; PPM: parts per million; CMFIS: conventional mechanical fuel injection system.     

A large-scale outdoor atmospheric simulation smog chamber for studying atmospheric photochemical processes: Characterization and preliminary application

Understanding the formation mechanisms of secondary air pollution is very important for the formulation of air pollution control countermeasures in China. Thus, a large-scale outdoor atmospheric simulation smog chamber was constructed at Chinese Research Academy of Environmental Sciences (the CRAES Chamber), which was designed for simulating the atmospheric photochemical processes under the conditions close to the real atmospheric environment. The chamber consisted of a 56-m³ fluorinated ethylene propylene (FEP) Teflon film reactor, an electrically-driven stainless steel alloy shield, an auxiliary system, and multiple detection instrumentations. By performing a series of characterization experiments, we obtained basic parameters of the CRAES chamber, such as the mixing ability, the background reactivity, and the wall loss rates of gaseous compounds (propene, NO, NO₂, ozone) and aerosols (ammonium sulfate). Oxidation experiments were also performed to study the formation of ozone and secondary organic aerosol (SOA), including α-pinene ozonolysis, propene and 1,3,5-trimethylbenzene photooxidation. Temperature and seed effects on the vapor wall loss and SOA yields were obtained in this work: higher temperature and the presence of seed could reduce the vapor wall loss; SOA yield was found to depend inversely on temperature, and the presence of seed could increase SOA yield. The seed was suggested to be used in the chamber to reduce the interaction between the gas phase and chamber walls. The results above showed that the CRAES chamber was reliable and could meet the demands for investigating tropospheric chemistry.     

Activity maintenance of the excised branches and a case study of NO2 exchange between the atmosphere and P. nigra branches

The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time.     

Second organic aerosol formation from the ozonolysis of -pinene in the presence of dry submicron ammonium sulfate aerosol

An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysisexperiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limitedexperiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments andrecorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particlesizer (SMPS), and α-pinene consumed was measured using GC-FID. Secondary organic aerosol (SOA) produced for seed-free systemis 100% organic in content, resulting from a sufficient supersaturation of low volatility organics to produce homogeneous nucleationfollowed by condensation to the aerosol. Secondary organic aerosol produced in seeded system is a mixture of organic and inorganicconstituents, initially forms via condensation onto the inorganic particles, and subsequent growth occurs via absorption into the organicsurface coating the inorganic core. Although the formation process and the size distribution for seed-free system and seeded system isdifferent, the ultimate mass of SOA formed is equal, and SOA yield for the two system located in the same regression line when usingone-product model, suggesting that the presence of dry ammonium sulfate seed has no measurable effect on the total aerosol yield, and the dry seed particle acts solely as a site upon which organic deposition occurs.     

鄂南4种典型土地利用方式红壤CO2排放及其影响因素

以湖北省咸宁地区分布的红壤为研究对象,采用静态箱法对4种典型土地利用方式（水稻-油菜轮作田,旱地,林地,果园）土壤CO₂的排放特征及其相关影响因子进行了观测研究.结果表明,4种利用方式土壤CO₂的年排放总量从高到低分别为水稻-油菜轮作田1 129 g/(m²·a),果园828 g/(m²·a),旱地632 g/(m²·a),林地533 g/(m²·a).土壤CO₂排放通量呈现明显的季节性变异,水田夏季淹水期排放低,而其它3种土壤都是夏季最高,春秋次之,冬季最低,并与对应的大气温度、土壤温度变化趋势基本一致.其中5 cm地温与4种土壤CO₂排放通量均成极显著的相关关系,且以林地的相关性最大.除水田外,其它土壤CO₂排放通量与大气温度均呈显著正相关关系.根据5 cm地温与CO₂排放通量的相关方程计算得出,4种利用方式红壤的Q₁₀分别为水田1.51,果园1.88,林地2.08,旱地2.7.土壤CO₂排放通量与土壤WFPS之间并没有明显的相关关系.土壤可溶性有机碳（DOC）含量与CO₂排放通量的变化趋势基本一致,且DOC在降水或淹水的情况下显著增大.