Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

Spectrophotometric Determination of Atmospheric Acidity by means of the Displacement of the Equilibrium of Acid-Base Indicators

A method is described for determining acidity by means of the spectrophotometric determination of the displacement of the equilibrium of açid-base indicators. The method is simple, sensitive and free of known interferences. There is no dependence on costly or sophisticated equipment and the results obtained are reliable and reproducible.     

Corrosive Effects of Mixtures of Pollutants

The corrosion films that form on metals and alloys during field exposure are generally chemical mixtures. It is clear that the formation of such films requires the presence of mixtures of atmospheric corrosive gases, or of a combination of corrosive gases and atmospheric aerosol particles. Thus, laboratory experiments designed to reproduce field effects must involve mixtures of corrosive constituents. In this paper we review the mixed corrodent experiments of ourselves and others, describe the synergistic effects of mixtures of pollutants on a variety of metals, and present the necessary ingredients for experiments designed to simulate the interactive effects of atmospheric corrosive constituents.     

Visualisation of the complexity of EUSES

The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters (inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation, on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency. The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters), and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity to 961, and the maximal dimension is 21.     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

红土吸附砷对其动电电位的影响

研究了遵义红土吸附砷对其动电电位的影响 ,从砷酸根浓度和体系pH对红土动电电位影响的角度作了探讨 ,结果表明 ,砷酸根离子浓度越大 ,Zata电位下降幅度越大 ,Zata电位也越低 ;随着体系pH的升高 ,氧化铁胶体动电电位逐渐下降 ,甚至改变了表面电位的符号。由此得出了红土吸附砷属于专性吸附的结论。     

Sodium dodecyl sulphate-enhanced desorption of atrazine: effect of surfactant concentration and of organic matter content of soils

A study was made of the adsorption-desorption of atrazine in aqueous medium in five soils with organic matter (OM) contents in the range 1.4-10.3% and also of the desorption of the herbicide in aqueous solutions of the anionic surfactant sodium dodecyl sulphate (SDS) at critical micelle concentrations (cmc) of 0.75, 1.50, 5 and 10. The adsorption and desorption isotherms in water together with the desorption isotherms in SDS solutions with concentrations of 0.75 and 1.50 cmc fit the Freundlich adsorption equation. All the desorption isotherms displayed hysteresis. The increase or reduction in hysteresis of the desorption isotherms in SDS solutions with respect to those of desorption in water depend on the SDS concentration and on the OM content of the soils. Below the cmc, SDS only increases the desorption of atrazine in the soil with the highest OM content (10.3%). However, above the cmc (5 and 10 cmc) the desorption of atrazine increases in all soils, the efficiency of desorption increasing with the OM content of the soils.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.     

Distribution of heavy metal contents of urban soils in parks of Seville

Several metals in urban soils of Seville were extracted by two methods, which respectively give estimates of the available and ‘quasi total’ contents. Although the soils did not show strong heterogeneity in their general properties, high dispersion of the contents in those metals with greater relative availability, Cu, Pb and Zn, as compared to others suggested that pollution with these three metals could occur in some sampling sites. It was shown that the contents in these metals tend to increase as the historic quarters of the city are approached. Using reference values given by the Québec Ministry of Environment it was shown that those green areas closer to the historic centre present contents in Pb, Zn and particularly Cu that often exceed the acceptable limits for residential, recreational and institutional sites. From background contents for Seville soils estimated from a park located on the outskirts, a pollution load index (PLI) for each sampling site was calculated for the set of these three metals. It was shown that the PLI tends to increase as traffic density increases and as distance from main traffic decreases, but poor regressions were obtained, suggesting that other variables different from traffic should be considered.     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.     

嗜盐菌的特性与高盐废水生物处理的进展

论述了嗜盐菌的形态特征、营养构成、生理特性和嗜盐机理，以及利用其特性在含盐有机废水处理中的应用，综述了国内外生化处理高含盐量有机工业废水的实验研究成果、在实际废水工程中的应用及其发展方向。对嗜盐菌的培养与驯化有一定的参考价值，对含盐废水处理工程的设计与运行有指导意义。     

Comparative study of accessibility of distinctive pesticides

Interactions of micro-contaminants with soil may play a crucial role in their environmental fate and possible harmful effects. Major goals of our investigations were to model the availability of widely used pesticides and characterize adsorption capabilities of distinctive soil types by the accomplishment of extensive comparative studies and application of several extraction methods. Environmental and biological relevance of these examinations is enhanced by the fact that intrinsic features and specific details of pesticide accessibility have not been revealed so far by a comparative approach. Five different experimental methods were assessed for modelling accessibility of five selected pesticides. The applied models for regaining the pesticides showed diverse efficiency in extraction capability in cases of the different soil types (sandy, brown forest and alluvial soils). The amounts of the obtained pesticides were determined by using gas-chromatography coupled to mass spectrometry (GC-MS) and high pressure liquid chromatography coupled to mass spectrometry (HPLC-MS). Accessibility of pesticides was also compared in cases of sterilized and real soil samples in order to estimate the extent of the influence of microflora. Aqueous extraction solvents proved to be suitable for accurate assessment of the accessible amounts of pesticides, as their effectivity was at least as high as that of the applied organic solvents. In our studies pesticide-soil interactions have comprehensively been characterized, and possible influences of environmental factors on the accessibility have also been revealed. Our study might be regarded as a tentative approach to model some significant circumstances playing key roles in pesticides' possible bioavailability.     

微量金属对废水厌氧处理效果的影响

以葡萄酒蒸馏废水的厌氧生物处理为例,研究了Fe、Ni、Co、Mo、Cu、Zn对厌氧反应器的COD去除率、出水中挥发性有机酸含量、气体产量、气体成分、pH缓冲能力和碱度等的影响.对比了微量金属投加前后,厌氧反应器污泥中微量金属含量的变化.得出微量金属具有提高厌氧运行效果的作用,其中,Co的作用要更大一些.Ni、Co、Mo在附着态、悬浮态污泥中具有逐渐积累的特点;Fe、Cu、Zn在附着态污泥中是淋失的,而在悬浮态污泥中变化不大.     

A review of neurotoxicity of microcystins

Cyanobacterial blooms-produced microcystins are secondary metabolites which can accumulate in the food chain and contaminate water, thus posing a potential threat to the health of aquatic animals and even humans. Microcystin toxicity affects not only the liver but also the other organs, i.e., the brain. The serious neurotoxicity effects caused by microcystins then lead to various symptoms. This review focuses on the neurotoxicity of microcystins. Microcystins can cross blood-brain barrier with the transport of Oatps/OATPs, causing neurostructural, functional, and behavioral changes. In this review, potential uptake mechanisms and neurotoxicity mechanisms are summarized, including neurotransmissions, neurochannels, signal transduction, oxidative stress, and cytoskeleton disruption. However, further researches are needed for detailed studies on signaling pathways and the downstream pathways of neurotoxicity of microcystins.     

响应面法优化袋式除尘器脉冲清灰性能

基于计算流体动力学的方法采用三维、可压缩、非稳态流动数学模型对袋式除尘器脉冲清灰过程进行了数值模拟,得到了滤袋内外压差,并与文献实验值进行了比较,验证了仿真模型的可靠性。基于响应面法研究了喷吹压力、喷吹高度、滤袋直径和滤袋长度对脉冲清灰性能的影响,得到这4个影响因子的二次多项式预测模型,并进行优化。结果表明,喷吹压力为0.3 MPa,喷吹高度为0.2 m,滤袋直径为0.16 m,滤袋长度为6 m时,内外压差峰值最优,优化结果与仿真模拟结果相差小于3%。研究结果为袋式除尘器脉冲清灰系统的设计与优化提供了重要参考。     

稀盐酸预处理对稻草厌氧消化的影响

为探明稀酸预处理对稻草厌氧消化的影响,采用不同浓度的稀盐酸溶液对稻草进行了浸泡预处理,并在完全混合厌氧消化条件下,研究了稻草厌氧发酵过程中的产气量、甲烷含量,发酵液中COD、pH值及挥发性脂肪酸(VFA)的变化情况.结果表明,增大稀盐酸溶液浓度会提高稻草厌氧消化反应的效果.分别经4%、8%和12%的稀盐酸溶液浸泡预处理...     

Assessment of the effects of herbicide spray drift on a range of plant species of conservation interest

With increasing use of herbicides there has been growing concern that spray drift from treated land will affect vegetation on adjacent nature reserves and other areas of high conservation interest. A preliminary attempt was made to assess this risk by placing a range of native plant species at different distances downwind from standardised drift events and assessing lethal effects and sublethal damage. Five herbicides were tested: asulam, 'Finesse' (chlorsulfuron + metsulfuron-methyl), glyphosate, MCPA and mecoprop. Applications were made at the appropriate time of years for each herbicide (autumn, spring and summer), and at both low and high wind speeds. The maximum safe distance at which no lethal effects were found was 6 m from the sprayer, but for most herbicides the distance was 2 m or less. Generally, damage symptoms were found at greater distances than lethal effects, but in most cases there was rapid recovery by the end of the growing season. These observations are consistent with drift-deposition models, in which the fallout of herbicide droplets has been measured. It is suggested that buffer zones surrounding nature reserves should be in the order of 5-10 m for ground sprayers to minimise the risk of herbicide impacts on these habitats.     

Biodegradability of surfactants and inhibition of surfactants to biodegradation of other pollutants

Changes of BOD/TOD and DOC with time were obtained for solutions of 9 synthetic surfactants and 2 fatty acid salts under various conditions. The cationic surfactants, ABM and ABDM, were not biodegraded at all and inhibited the biodegradation of a synthetic sewage. LAS was not biodegraded at concentration of 30 mg/l and higher and inhibited the biodegradation of the sewage.     

Mechanisms of biodegradation of dibenzoate plasticizers

Biodegradation mechanisms were elucidated for three dibenzoate plasticizers: diethylene glycol dibenzoate (D(EG)DB), dipropylene glycol dibenzoate (D(PG)DB), both of which are commercially available, and 1,6-hexanediol dibenzoate, a potential green plasticizer. Degradation studies were done using Rhodococcus rhodochrous in the presence of pure alkanes as a co-substrate. As expected, the first degradation step for all of these systems was the hydrolysis of one ester bond with the release of benzoic acid and a monoester. Subsequent biodegradation of the monobenzoates of diethylene glycol (D(EG)MB) and dipropylene glycol (D(PG)MB) was very slow, leading to significant accumulation of these monoesters. In contrast, 1,6-hexanediol monobenzoate was quickly degraded and characterization of the metabolites indicated that the biodegradation proceeded by way of the oxidation of the alcohol group to generate 6-(benzoyloxy) hexanoic acid followed by β-oxidation steps. This pathway was blocked for D(EG)MB and D(PG)MB by the presence of an ether function.The use of a pure hydrocarbon as a co-substrate resulted in the formation of another class of metabolites; namely the esters of the alcohols formed by the oxidation of the alkanes and the benzoic acid released by hydrolysis of the original diesters. These metabolites were biodegraded without the accumulation of any intermediates.