阴极电势对微生物电合成系统还原CO2合成有机物性能的影响

采用微生物电合成系统（MES）还原CO₂合成有机物,从微生物菌群、有机物积累量、库伦效率、电化学分析等多个角度研究了阴极电势对MES还原CO₂合成有机物性能的影响。实验结果表明：阴极电势为-0.70 V时,甲酸和乙酸的积累量均最大（分别为1.554 mmol/L和2.754 mmol/L）,系统的总库伦效率最大（为81.42%）;在MES中,醋杆菌（Acetobacterium sp.）、假丝酵母菌（Candida sp. S）、地杆菌（Geobacter sp.）为优势菌种。     

Dose Dependent Interactions Between Ammonification Potential and Bacteria in Three Tropical Pond Ecosystems

Using six different doses of peptone (0.25, 0.50, 0.75, 1.0, 1.25 and 1.50 gl^-1) and nine different periods of inclubation (1, 2, 3, 4, 6, 8, 10, 12 and 14 days), the rates of ammonification potential (AP) were monitored in three tropical ponds of differetn ecological status, during winter and summer periods. During the winter, the AP (ammonifying bacteria) exhibited peaks on day 4 of incubation in all the test doses of peptone in all the three ponds, except in the lowest dose in eutrophic and chemically polluted pond where the peaks preceded by a day. the responses of AP to the lowest doses of substrate did not differ between summer and winter, while the AP-peaks at higher doses were delayed by 2 days in summer. the concentrations of nitrate in vitro were the inverse and direct functions of the AP and dissolved oxygen of water. at moderate dose (0.75 gl^-1) of peptone, both AP and dissolved oxygen at higher doses, and by AP at the lowest dose of peptone.     

POTENTIAL,ACTUAL, AND EQUILIBRIUM EVAPOTRANSPIRATION IN A WHEAT FIELD 1

ABSTRACT: This paper examines the relationship between both potential (E*) and nonpotential evapotranspiration and equilibrium evapotranspiration (EQ) in an irrigated wheat field in southcentral Alberta, Canada. The control exercised by surface wetness and root reservoir moisture content in determining the value of the Priestley-Taylor constant a is explored. Also investigated is the relationship between a and the vapor flux fraction ET/(R-G) where ET is the actual evapotranspiration, R the net radiation, and G the soil heat flux. It is shown that evapotranspiration occurred at the potential rate (E*) when the available soil moisture (ASM) within the root zone was ≥3 percent. a varied from 0.84 for a dry soil to 1.49 for a saturated soil. The mean a for E* was 1.24. Surface wetness sustained evapotranspiration at the potential rate when such wetting exceeded 2mm d^?1 following a period of prolonged drawdown of soil moisture, α and ET/(R-G) were positively correlated and this correlation strengthened with increasing soil moisture for constant values of the energy partitioning factor s+γ/s where s is the slope of the saturation humidity-temperature curve and γ is the psychrometric constant. ET=EQ when ETI(R-G) lay within the range of 0.59 to 0.82 corresponding to Bowen ratio (β) values of 0.22 and 0.69, respectively.     

COMPARISON OF THERMAL SCANNING AND IN SITU TECHNIQUES FOR MONITORING THERMAL DISCHARGES1

ABSTRACT: In situ and remote sensing techniques for measuring thermal plumes are compared for data taken at the Point Beach Nuclear Power Plant on Lake Michigan for five separate occasions. The in situ method employed a boat whose position was determined with a microwave ranging system. Temperatures at the surface and at various depths were measured with fast response thermistor probes. The remote sensing technique utilized an infrared scanner in the 8 to 14 micron range. Comparison of the plumes indicates good agreement with respect to plume configurations, areas within isotherms and centerline temperature decays for all except one occasion, a calm day characterized by no waves, low wind and ambient current velocities. Robable reasons for disagreement under such ambient conditions are discussed. The inherent advantages and disadvantages of each method are discussed in light of the results of the five sets of data. This includes both the data collecting and data analyzing procedures. It is concluded that judicious combination of both methods offers a better picture of thermal plumes than can be obtained by either technique alone.     

PRECISE WATER VELOCITY MEASUREMENTS USING PHOTOGRAMMETRIC TECHNIQUES1

ABSTRACT Necessary input parameters for studying mixing zone characteristics of thermal plumes are horizontal surface and subsurface water velocities. Using time lapse aerial photography and analytical photogrammetric techniques, movements of drogues in an effluent plume were traced. From these traces accurate velocity vectors were obtained. Photographic coordinates of drogue images were measured using a glass scale. From the photo coordinates and the results of a ground control survey, an analytical solution was made for positions of drogues in the water at known intervals of time. Drogue positions were mapped for selected exposures thereby providing a visual display of velocity vectors in the study area. A rigorous error analysis was performed to determine the validity of the computed results.     

论重大危险源监控与重大事故隐患治理

重大危险源是指工业活动中危险物质或能量超过临界量的设备、设施或场所。工业活动中重大火灾、爆炸、毒物泄漏事故 ,尽管其起因和影响不尽相同 ,但都有一个共同的特征 :其根源是存在大量的易燃、易爆、有毒物质或具有引发灾难事故的能量。重大危险源同重大事故隐患是两个既有联系又有区别的概念 ,前者强调设备、设施、场所中存在或固有的危险物质 (能量 )的多少 ,后者则可以认为是出现明显缺陷 (人的不安全行为 ,物的不安全状态或管理上的缺陷 )的重大危险源。从重大事故隐患治理到重大危险源普查 (申报 )、监控是预防重大事故理论与技术的进步 ,是从源头抓预防 ,是落实预防为主 ,关口前移的具体体现 ,也是国家安全生产法律、法规的强制要求。笔者论述了重大危险源监控、重大事故隐患治理与重大事故预防之间的区别与联系 ,用事故是能量意外释放的观点 ,论述了安全是相对的、危险是永存的、事故是可以预防的 ;分析了建立重大危险源监控体系与重大事故预防控制体系的几大要素 ,即危险源辨识、评价、分级管理与监控 ,应急救援等。     

浮力羽流低风速的多点实时测量

作者发展了一种浮力羽流低风速的多点实时测量技术。测头端部安装耐热玻璃小球,直径0.8mm,球内装有热电偶和加热电阻丝,测头将风速转换为热电偶的电势。每支测头必须经过专用校准热风洞的单支校验。使用巡回检测系统记录多个测头的电位,得到流场各点风速的统计平均值,实现了低风速场的多点实时测量。本测量系统对火灾科学、环境科学和气象学的实验研究和实地观测是很有用的测量技术。     

事故与熵──事故发生可能性计算的新方法

从熵增加的观点描述了事故的本质，剖析了人机系统的实质与特性，提出了风险熵与事故势的概念，给出了计算机风险熵与事故势的方法。结果表明，系统具有二重性。在系统运行期间，系统具有封闭体系的特性；在休整期间，系统具有开放体系的特性。事故是运行系统的必然发展趋势，是运行系统的固有属性，是一种自发过程。由于在系统熵增加的过程中信息及能量的交换，可以把事故定义为系统熵增加的结果。避免事故发生的原理是不断地向系统输入信息或负熵以抵消系统内部的熵增加。     

A GEOGRAPHIC INFORMATION SYSTEM TO PREDICT NON-POINT SOURCE POLLUTION POTENTIAL1

ABSTRACT: Bacterial densities (total coliform, fecal coliform, and fecal streptococci) and suspended solids in runoff from a feedlot, pasture, and corn field were measured. Densities of fecal coliform were highest from the feedlot but were 1000 to 10,000 times greater than the water quality standard for swimmable waters from all three land uses. Densities of fecal streptococci were highest from the corn field, which suggests that wildlife are the source of bacteria. Fecal coliform/fecal streptococci ratios distinguished cattle from wildlife as the source of bacterial pollution both among land uses and among seasons of the year. Suspended solids concentrations in runoff ranged from 423 to 925 mg/l and were highest from the corn field. A Geographic Information System (GIS), which utilizes a raster or grid-cell format, was developed to include algorithms associated with non-point source pollution. The system accepts digitally mapped information on soil type, topography, and land use. It calculates characteristics such as slope and slope length, and relates these characteristics to soils and land use parameters in order to produce three dimensional maps of runoff potential, sediment pollution potential, and bacterial pollution potential. It offers the advantages of retaining the geographic character of pollution potential information and of conveying in three-dimensional graphical terms the effects of topography, soil type, land use, and land management practices.     

WATER BALANCE OF PACIFIC ATOLLS1

ABSTRACT: This study presents an estimate of water balance components for Pacific atolls under average dimatological conditions. Figures show annual potential evapotranspiration, annual recharge for rain-fed and aquifer-fed vegetated areas, and the number of months that potential evapotranspiration exceeds actual evapotranspiration (indicating water stress) under average conditions. The method relies on the assumption that small islands have minimal influence on cloudiness and precipitation. The potential evapotranspiration is computed using the equilibrium evaporation concept, and estimates of monthly soil water storage and recharge follow Thornthwaite's bookkeeping method. Gradients in potential evapotranspiration run primarily north-south, though for the equatorial zone potential evapotranspiration declines from east to west, opposing the trend in rainfall. Recharge estimates range from 250 mm in the central Tuamotu Archipelago and zero in eastern Kiribati to over 2000 mm per year in the southern Caroline Islands (U.S. Trust Territory) and Solomon Islands. The sensitivity of the model to intra-month rainfall variability and a range of available soil moisture values is discussed.