Bench Scale Evaluation of a Chemo-biochemical Process for Desulphurization of Gaseous Streams Containing Hydrogen Sulphide

Gases and suspended particulate matter are sampled and measured in situ at different sites within the city of Madrid to determinethe air pollution in the city. Lead concentrations in air are also determined. The information needed to assess levels of contaminants is obtained combining several analytical techniques,which provide real time concentration data of particles andgases. Particulate matter (PM), SO₂, CO, O₃, NO_x,NO₂, CH₄, total hydrocarbons and Pb were measured. Concentrations of pollutants are averaged over periods of hours,days, months and years. Variations of contaminant concentrationsin the last years are presented. Spatial and temporal distribution follows that of the traffic, the main source of pollution in Madrid City. Some specific measurements were carriedout to understand the influence of traffic emissions at themeasured site. Further, all measured concentrations never exceeded the European Union Directives.     

城市尺度生态足迹模型应用中不同参数选择的影响分析

针对生态足迹模型在城市尺度上应用中的均衡因子、产量因子和平均产量3个参数的不同取值方式,分别对不同参数应用模式下城市生态足迹核算的内涵和结果进行影响分析。基于对参数的应用条件和效果的解析,指出传统生态足迹模型的应用中存在误差模糊化处理和全球可比性差的问题,＂国家公顷＂生态足迹模型进行消费来源分解更贴切的体现区域特征。基于参数的尺度效应分析,指出生态足迹模型存在空间可比性和体现区域特征的悖论。通过对参数内涵和模型缺陷分析,探讨均衡因子和产量因子核算中的问题,空间可比性来源于平均产量的引入,并指出模型应用中的贸易调整过程存在缺陷,进而为生态足迹理论及方法论的进一步完善提供依据。     

苎麻茎秆台架切割试验与分析

为了给苎麻收割机的研制提供切割理论基础,该文进行了苎麻茎秆切割参数的试验研究。该文利用自行设计的试验台架进行苎麻茎秆的切割试验,研究往复式单动刀及双动刀切割器不同刀片几何参数(刀片长度、刀刃类型)、不同切割线速度和不同茎秆喂入速度对切割性能(切割功耗、切割质量和综合评分值)的影响。根据各个因素特点,论文采用多因素正交试验的方法确立两水平因素(刀刃类型、刀片长度和动刀组数)的最优水平组合,然后固定两水平因素的最优水平组合,以切割线速度和茎秆喂入速度为试验因素进行二次回归正交旋转设计试验来获得因素的最佳参数。根据多因素正交试验结果,采用往复式双动刀切割器,选用锯齿刃长刀片(120 mm)为最优水平组合。根据二次回归正交旋转设计试验结果,当切割线速度为0.878 9 m/s、茎秆喂入速度为0.862 4 m/s时,单位长度割幅切割功率最小,为281.408 4 W;当切割线速度为1.161 4 m/s、茎秆喂入速度为0.711 7 m/s时,单位面积切割失败株数最少,为5.691 1株;当切割线速度为1.092 0 m/s、茎秆喂入速度为0.722 9 m/s时,评分值最高,为86.7180分。综合试验结果,苎麻切割试验理论最佳水平组合为:切割线速度1.092 0 m/s、茎秆喂入速度0.722 9 m/s,采用往复式双动刀切割器,选用锯齿刃长刀片(120 mm),此时单位长度割幅切割功率为318.814 5 W,单位面积切割失败株数为6.006 4株。研究结果为后续苎麻收割机切割部件的研制以及切割行走速比的选择提供了基础理论数据。     

Molecular Level Protein Composition of Flour Mill Streams from a Pilot‐Scale Flour Mill and Its Relationship to Product Quality

Flour mill streams prepared from two Australian and two New Zealand wheat cultivars using a pilot‐scale roller mill were analyzed for rheological and baking quality characteristics and for protein composition using size‐exclusion HPLC. Differences in mill stream protein composition, on an industrially relevant scale, and the relationships between the distribution of proteins (and their degree of thiol exposure) and the technological quality of the flour mill streams were examined. Consistent, significant differences were observed in the physicochemical and processing characteristics of the flour streams. Between mill streams, changes in the quantities of the storage protein groups were more marked than for nonstorage protein groups. Changes in protein composition differed between the break and reduction stream flours. In contrast, the degree of exposure of thiol groups on the various protein groups followed different patterns between mill streams. Numerous significant relationships were observed between dough mixing and product baking tests and the composition and thiol exposure state of the various protein classes. These relationships are discussed in context of manipulating the processing quality of flour‐based products using mill streaming. A possible role for exposed thiol groups on storage proteins in the phenomenon of flour “aging” is suggested.     

Effects of Silver on the Photocatalytic Degradation of Gaseous Isopropanol

Water, Air, & Soil Pollution - The decomposition of gaseous isopropanol (IPA) by UV/TiO2 process in an annular photoreactor was studied under various conditions such as UV light intensity and...     

城市河流及其生态治理规划研究

城市河流是城市空间的重要组成部分,具有多种社会经济功能和环境生态效益。目前我国城市河流存在着渠道被挤占填埋、硬化渠化以及污染严重等问题,并对整个城市生态环境造成严重影响,根据城市河流治理规划的发展趋势提出了还河流以空间、建设生态河堤、营造城市水景以及进行排污控制等项措施。     

城市河流及共生态治理规划研究

城市河流是城市空间的重要组成部分，具有多种社会经济功能和环境生态效益。目前我国城市河流存在着渠道被挤占填埋、硬化渠化以及污染严重等问题，并对整个城市生态环境造成严重影响，根据城市河流治理规划的发展趋势提出了还河流以空间、建设生态河堤、营造城市水景以及进行排污控制等项措施。     

Effect of Gaseous Acetic Acid Treatment on Breadmaking Properties of Flour

Eleven different wheat flours of varying protein content were treated with gaseous acetic acid. Each wheat flour exhibited maximum breadmaking properties (bread height and specific volume) at different levels of gaseous acetic acid treatment. There was a relationship (r = +0.7384) between the level of gaseous acetic acid treatment required for maximum breadmaking properties and the protein content of the wheat flour. Wheat flours with higher protein contents were more resistant to the decrease in pH value due to acetic acid treatment.     

水平梯田减蚀作用分析

通过理论分析,证明了由于坡地修梯田改变了原有小地形,使土地具有更强的减蚀能力。径流小区试验表明,与坡耕地相比,水平梯田的减蚀效益达到92％～100％。     

Effect of Gaseous Acetic Acid on Dough Rheological and Breadmaking Properties

Breads baked from wheat flours (protein contents 14.1–16.5% at 14.0% mb) that were pretreated with 2–3 mL of gaseous acetic acid per kg of wheat flour, showed maximum bread height and specific volume (cm³/g). Flour-water suspension and the crumb pH values were gradually decreased with increased amounts of acetic acid. Gas generation and dough expansion tests with bread dough showed that the addition of the same amount of acetic acid, which achieved maximum specific volume, also showed the highest rate of gas generation and dough expansion. However, increasing acetic acid decreased these values. Scanning electron microscope (Cryo-SEM) observation showed that the bread dough made from the same acetic acid-treated flour indicated continuum and no cracks in the dough matrix. Evaluation of mixograms showed the decrease of mixing stability with increased acetic acid levels. Viscosity and water binding capacity of flour-water suspensions were sharply increased by the addition of acetic acid at pH 5.0–3.5.     

脱硫石膏对碱化土壤胶体絮凝的影响

为明确脱硫石膏改良碱化土壤胶体絮凝过程的离子交换作用,设置了碱化土壤组和碱化土壤胶体组.在不同土水比(1 ︰ 5、1 ︰ 10、1 ︰ 20(m ︰ V))条件下加入不同量脱硫石膏量(0.1％～2％,m ︰m)作为碱化土壤组,以及向利用土水比为1 ︰ 100的方法制备碱化土壤胶体中加入不同量的脱硫石膏作为胶体组,以分析...     

Insights into Human Impacts on Streams from Tolerance Profiles of Macroinvertebrate Assemblages

We present the concept of assemblage tolerance profiles (ATPs) as an aid to freshwater bioassessment, and illustrate it with a practical example. An ATP describes the proportion of taxa in an observed assemblage that is estimated to tolerate each level of a specific stressor within a defined range. We used an extensive compilation of biomonitoring field data to estimate the lower tolerances for pH and dissolved oxygen (DO) of common families of macroinvertebrates in rivers of south-eastern Australia. These limits were then used to establish ATPs for macroinvertebrate assemblages at 30 sites across six river systems with varying levels of exposure to drainage from disused mines and discharges from sewage treatment plants. We hypothesised that sites with more exposure to mine drainage would have ATPs indicating greater tolerance of low pH, whereas sites with more exposure to sewage discharges would have ATPs indicating greater tolerance of low DO, and found that these hypotheses were confirmed for five of the six river systems. We suggest that stressor-specific ATPs, based on tolerances derived from either field distributions or laboratory tests, can help to verify or eliminate candidate causes of inferred human impacts on aquatic ecosystems.     

Observations on Gaseous and Aerosols Components of the Atmosphere and Their Relationships

Measurements of sulphur dioxide, ozone, ammonia, and soluble inorganic components of the atmospheric aerosol were made at a site in central southern England. Ammonia, ozone, and nitrate aerosol in winter were shown to exhibit significant diurnal variation. Ozone showed a typical diurnal variability, the magnitude of which was dependent upon wind speed. The lower night-time ozone concentrations at lower wind speeds were attributed to depletion inside nocturnal boundary layers by dry deposition. Ammonia, in contrast, showed a different behaviour, whereby the diurnal cycle was more pronounced at higher wind speeds, indicating that the cycle was unlikely to be the result of dry deposition at night. Ammonia concentrations showed a temperature dependence and the diurnal cycle of ammonia at this site appears to be the result of a temperature-driven emission signal. Of the total reduced nitrogen, NH_x (NH_x = NH₃ + NH₄ ⁺ aerosol), the phase was dominant and it is likely that more than 60% of the boundary layer NH_x is in this phase. The loss term of ammonia by reaction with acid sulphate aerosol is likely to be greater than that by dry deposition on a UK scale. Nitrate aerosol showed a positive correlation with sodium aerosol, once the effect of mutual correlations with sulphate and ammonium were removed. This correlation effect, in combination with evidence of a marine-oriented directional dependence of nitrate aerosol, and negative non sea-salt chloride aerosol from the same ‘marine’ sector, shows the potential importance of the formation of sodium nitrate aerosol from reaction of dinitrogen pentoxide, or possibly nitric acid or nitrogen dioxide with sodium chloride aerosol. It is likely that this provides the major route of nitrate into rain, not the scavenging of nitric acid vapour. Aerosol sulphate, nitrate, and ammonium have been measured at Harwell since 1954. Sulphate aerosol increased up until 1976 and has declined subsequently. Nitrate aerosol has increased over the whole period, whereas ammonium aerosol follows a similar pattern to that of sulphate, but with an equivocal direction of trend after 1976. Sulphate, nitrate and ammonium aerosol all show a similar statistically significant seasonality. A historical inventory of ammonia emissions shows a clear correlation with ammonium aerosol.     

Physicochemical and Rheological Analysis of Flour Mill Streams

Knowing the quality of mill streams is very important for obtaining standardized flours with intended qualities for specific applications. The physicochemical and rheological quality of wheat flour mill streams obtained through industrial milling were analyzed. Rheological behavior was tested using alveograph, rheofermentograph, and mixolab equipment. The results obtained indicate that the starch damage, protein quality, and rheological properties vary with the mill streams. Three variants of breadmaking flours, obtained by blending different milling fractions without negatively affecting the extraction and final product quality, were characterized.     

Impacts on Streams from the Use of Sulfur-Based Compounds for Dechlorinating Industrial Effluents

We evaluate environmental impacts associated with sulfur-baseddechlorinating agents (sodium bisulfite and sodium thiosulfate)commonly used in industrial wastewater treatment by presentingdata from two examples for Department of Energy facilities inTennessee and Kentucky. One case involved a fish kill (> 24,000 fish) caused directly by sodium bisulfite; the second describes a near-miss situation resulting from over-dosing with sodium thiosulfate. Toxicity tests showed that overfeed situations withsodium thiosulfate or sodium bisulfite can depress pH and dissolved oxygen, causing mortality of fish. Bacteria also can metabolize some sulfur-based dechlorinating agents, thereby increasing the potential for reductions in pH and concentrationsof dissolved oxygen. Although removing toxic levels of chlorine is important when releasing chlorine-containing wastewaters to aquatic systems, waste-treatment plant operators should also beaware of significant impacts that can occur if sulfur-based dechlorinating agents are used to excess.     

Quantification of Bacterial Populations Indigenous to Acidic Drainage Streams

Acid mine drainage (AMD) from mining activities can cause majorenvironmental problems. The acidity is due in part to the microbial oxidation of sulfide minerals in the exposed ores. Aslittle is known about seasonal variations of microbial populationsizes in AMD, the objective of this investigation was to quantifythe principal bacterial populations (iron-oxidizing acidophiles, sulfur-oxidizing acidophiles, sulfur-oxidizing neutrophiles, andacidophilic heterotrophs), with respect to season. The AMD sites sampled were four streams emerging from a copper/nickel tailingsarea. All bacterial populations with the exception of acidophilicsulfur oxidizers were recovered throughout the year. The most numerous bacteria were acidophilic heterotrophs and iron-oxidizing acidophiles. Surprisingly, there were no obvious trendsin the relative abundance of the various bacterial groups as a function of season. Recovery of the various bacterial groups at an incubation temperature of 4 °C indicated that psychrotrophic members do exist. During the course of the investigation, it was observed that thenumber of Acidithiobacillus ferrooxidans (Thiobacillusferrooxidans) colonies recovered on iron salts purified agarose,a preferred medium, was highly variable. The variability was attributed to the presence of non-iron-oxidizing satellite bacteria, the growth of which could be suppressed by increasingthe concentration of the electron donor ferrous sulfate.     

基于河流网络结构和NDVI集成的流域植被变化研究--以旬河流域为例

利用GIS模拟旬河流域河流网络结构，根据河流网络结构建立缓冲区，分别研究了不同等级河流缓冲区内，1997年和2004年相同时段NDVI值的分布特征，分析了河流等级与其缓冲区内NDVI值的关系。结果发现，利用GIS模拟的山地数字河网能够很好地与真实河网吻合；河流等级与其缓冲区内的NDVI值存在负相关关系；2004年河网缓冲区内NDVI值分布较1997年好，说明近几年旬河流域生态建设成效显著。     

双流传动履带式车辆实现方向盘转向的台架试验

为了使履带车辆的转向操作简便,并降低发动机的功率储备,在现有静液压双流差速转向装置的基础上,设计了一套与其匹配的采用方向盘操纵的控制装置,利用方向盘转角来控制两个定量马达的转速,再通过可差速传动的机械式变速箱分配到两侧驱动轮上,从而实现履带车辆双流传动装置转向期间车辆自动无级降速.通过台架空载试验测得车辆两侧驱动轮输出轴转速与方向盘转角之间的对应关系,并与理论计算仿真结果进行比较.结果表明:使用方向盘转向来实现履带车辆转向期间自动无级降速是可行的,为进一步研究方向盘操纵双流传动履带车辆转向装置提供充分可靠的理论依据.     

Comparison of Wind Erosion on Various Agricultural Lands

This investigation was conducted to compare wind erosion on three different agricultural lands (dryland, wastewater-irrigated land, and freshwater-irrigated land) in southeastern Iran. This region consists of 11500 km² of arid to semi-arid lands and is one of the driest regions of the country with high population density. Average annual rainfall of the region ranges between 50 and 60 mm. The temperature data indicate that July is the warmest month, when the temperature rises to more than 50 °C, and January is the coldest month of the year, with a minimum temperature of ?12 °C. The warm winds blow over the region of Sistan for about 120 days from June to September. The dominant wind directions are north and northwest. Twenty plots were designed randomly (in a completely randomized design) in this study to compare two irrigated areas, freshwater-irrigated land and wastewater-irrigated land, to dryland (control fields). The treatments were repeated three times. Ten data sets were taken during the experimental period, and the means were calculated and reported. The data indicated that wastewater-irrigated land benefitted from reduced soil erosion, increased soil fertility status (i.e., soil organic matter and nutrient contents), and increased soil moisture content. Soil losses by wind erosion in the wastewater-irrigated land, freshwater-irrigated area, and dryland in the study area were 185.2, 339.8, and 554.4 tons ha^?1, respectively. In addition, the study sites lost 1.3, 2.4, and 4.6 cm of soil by wind erosion, respectively.     

Effect of Abiotic and Biotic Factors on the Photo-Induced Production of Dissolved Gaseous Mercury

This study was conducted to evaluate the contribution of environmental factors such as solar radiation and dissolved organic matter (DOM) on the photo-induced dissolved gaseous mercury (DGM) production through laboratory experiments using field water samples collected from wetlands. DGM production was more significantly influenced by UVB intensity than UVA. DGM formation was also significantly affected by DOM chemical structure/composition rather than its concentration. Increasing NO ₃ ^? concentration limited DGM production, but photo-induced Hg oxidation stimulated by NO ₃ ^? would possibly occur when the NO ₃ ^? level is more than twice the DOC level. The addition of phosphorus into the field water samples induced a slight increase of DGM production; however, the addition of nitrogen decreased DGM formation, suggesting that an increase of limiting nutrients in water may promote biotic DGM production. Experiments using a Selenastrum capricornutum monoculture solution showed that cell density had a positive effect on DGM production. Moreover, the difference in DGM production between filtered and unfiltered samples showed that S. capricornutum significantly produced biotic DGM under UVA irradiation. Finally, our results imply that environmental factors such as light intensity, DOM sources, and site-specific microorganisms can significantly affect photo-induced Hg transformation.