上下导气系统对生物反应器压实垃圾中渗滤液和填埋气迁移的影响研究

建立了2组实验室模拟填埋场生物反应器,利用上层和下层同时导排填埋气的方法,研究了填埋气和渗滤液在垃圾体中的产生和迁移情况.并在考虑渗滤液回灌的情况下,设置了C1(渗滤液回灌前加压)、C2(渗滤液回灌后加压)2组对照实验.结果表明,C1在加压后出现短暂的水位雍高现象并在第33 d后消失,而C2一直未出现水位雍高现象,上下同时导气系统能促进渗滤液和填埋气排出,#有效缓解和消除水位雍高.压力促使C1、C2的填埋气由往上迁移转变为往下迁移,C1经历了10 d的填埋气向下迁移准备期,而C2在回灌后填埋气直接往下迁移,回灌会促进孔隙通道打开,有利于气液向下排出.     

Application of a new generation of complexing agents in removal of heavy metal ions from different wastes

Complexing agents are extensively applied in many fields of industry. They are used to provide effective controlling trace metal ions in cleaning industries, textile, pulp and paper production, water treatment, agriculture, food industries, etc. Recently, the low biodegradability of these ligands and their accumulation in the environment has become a cause for concern. Therefore, replacement of ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid by more environmentally friendly chelating agents is highly desirable. So far, these acids and their salts have been applied as components of household chemistry, cosmetics, modern microelement fertilizers and agrochemicals. This paper reviews the sorption of heavy metal ions such as Cu(II), Zn(II), Cd(II) and Pb(II) in the presence of the above-mentioned complexing agents on commercially available anion exchangers of different matrix. The obtained sorption results were fitted using the Langmuir and Freundlich sorption isotherm models. The kinetic data were also analysed using the Lagergren, Ho and McKay sorption kinetic equations. The studies were carried out considering the effects of such important parameters as phase contact time, initial concentration, pH and temperature.     

Prenatal diagnosis and treatment of fetal long QT syndrome: a case report

We report a case of a fetus presenting with bradycardia, intermittent atrioventricular (AV) block, ventricular tachycardia (VT) and the signs of fetal congestive heart failure (ascites and scrotal hydrocele) during mid-gestation. Prenatal treatment with β-adrenergic blocker (propranolol) and digitalis glycosides was prescribed because of suspicion of long QT syndrome occurring with fetal congestive heart failure. The male baby was born at 39 weeks of gestation and showed a prolonged QT interval (QTc = 492 ms) and frequent variable AV block or alternating left and right bundle branch block, depending on the atrial rate. Prenatal administration of lidocaine failed to correct the fetal VT. Conversely, propranolol decreased the attack frequency of fetal VT. Postnatal administration of the K⁺ channel opener (nicorandil) successfully shortened the QT interval and improved the outcome. Copyright © 2002 John Wiley & Sons, Ltd.     

Monitoring acoustically tagged king prawns <Emphasis Type="Italic">Penaeus</Emphasis> (<Emphasis Type="Italic">Melicertus</Emphasis>) <Emphasis Type="Italic">plebejus</Emphasis> in an estuarine lagoon

Fine-scale movement patterns in penaeid prawns are rarely observed in situ, but are essential in understanding habitat use, foraging, and anti-predator behaviour. Acoustic telemetry was applied to examine the activity, space utilization, and habitat use of the eastern king prawn Penaeus (Melicertus) plebejus, at small temporal and spatial scales. Tracking of sub-adult P. plebejus (n = 9) in Wallagoot Lake (36.789°S, 149.959°E; 23 April–12 May 2009) and calculation of a minimum activity index (MAI) revealed high variation in activity rates across diel periods and in different habitats. Elevated activity rates and movement indicated foraging in unvegetated habitats during the night. Areas within the 95 and 50% space utilization contours averaged 2,654.1 ± 502.0 and 379.9 ± 103.9 m², respectively, and there was a significant negative relationship between these areas and prawn activity rates in unvegetated habitats. This study provides the first estimates of prawn activity rates and space utilization in the field. Application of acoustic telemetry can increase knowledge of prawn movements and their interactions with other marine species in different habitats.     

The role of safety research in road safety management

Mobility is a matter of great importance in daily life: However, it also causes costs and involves accident risks. To make mobility safer and reduce accident risks, a scientifically based road safety management is needed. Within such a safety management system, a concert of adequate and efficient strategies, tools and measures is developed and implemented. To ensure that the chosen means are efficient they should be derived from research evidence. Secondly, research is also needed to regularly monitor the impact of road safety management tools, serving as a “controlling instrument” for the appropriateness of safety management efforts. This article explains the main strategic aspects of safety management in Germany and illustrates it exemplarily on the basis of two recently implemented road safety measures.     

Feasibility study on high-temperature sorption of hydrogen sulfide by natural soils

In this study, seven natural soils were tested for the sorption of hydrogen sulfide from coal gasification gas at high temperature. Results indicate that the LP natural soil has the best performance and the highest sulfur sorption capacity. After extracting free iron oxides, most natural soils have no sorption efficiency. The free iron oxides, therefore, proved to be the major components that react with hydrogen sulfide to form iron sulfides. The sulfur sorption capacity, either determined by EA or breakthrough time, is very close to the theoretical value based on the stoichiometric calculation with the content of free iron oxides. Moreover, the presence of CO is a positive effect while H2 is a negative effect. This can be explained via the water-shift reaction. On the basis of the results of temperature-programmed sulfidation (TPS), the starting temperature for the sorption of hydrogen sulfide is between 623-673 K. From the analyses of temperature-programmed oxidation (TPO) and XPS, the iron polysulfides are the major products and approximately 90% regeneration efficiency can be theoretically achieved while the temperature is controlled higher than 813 K. In the regeneration tests, the results show that the LP natural soil can be regenerated and thus reused after the oxidation process. No significant degeneration occurs on the LP natural soil after five sorption/regeneration cycles. The sulfur sorption capacity of the tenth regenerated soil can be achieved at least 80% compared to the fresh one. The experimental analyzed SO2 concentration from the regeneration process is almost identical to the theoretical calculated equilibrium concentration of the process. Maghemite is the main product after the regeneration process.     

Survey of urinary nickel in residents of areas with a high density of electroplating factories

The soil metal contamination arising from the discharge of the high density of electroplating factories in the geographic center of Taiwan has prompted concern about human exposure to harmful metals. This study aimed to determine the levels of nickel (Ni) in urine of residents living in the high vs. low factory-density areas, and to examine how these levels relate to gender and age. A total of 660 subjects, resident in the area for the last five years, were sampled according to the stratified random sampling approach, at ages 35-44, 45-54, and 55-64years for both genders. Metals in urine samples were analyzed by inductively coupled plasma mass spectrometry (ICPMS). The geometric mean (95% confidence interval (CI)) of urinary Ni was 6.30 (5.99-6.62)mug/l. The 0.95 parametric reference interval (90% CI) of urinary Ni was estimated to be 1.74 (1.62-1.88) to 22.73 (21.14-24.44)mug/l. Subjects in the areas with a high density of electroplating factories had significantly higher urinary Ni levels than those in the low-density areas, but both types of areas had obviously higher urinary Ni levels when compared to the non-occupationally exposed population from western countries. The health significance of elevated urinary Ni and its causative factors remain to be determined.     

Effect of humic acids,nitrate and oxygen on the photodegradation of the flubendiamide insecticide: identification of products

Flubendiamide is a ryanodine insecticide that shows a strong insecticidal activity and is relatively safe for non-target organisms. Actually only flubendiamide and its product desiodo-flubendiamide have been studied during catalytic degradation using TiO₂ and ZnO. Therefore, here we tested the photocatalytic removal of flubendiamide in the presence of nitrates or humic acids. Degradation kinetics were monitored using high-performance liquid chromatography ultraviolet–visible detector. Product identification was done using a high-resolution time-of-flight mass spectrometer coupled to a gas chromatograph (GC-HRMS). Results show that the addition of humic acids at 10 mg l^?1 increased the removal of flubendiamide more than five times. The addition of nitrate ions at 10 mg l^?1 had no influence. The removal of flubendiamide was more than ten times faster in experiments with oxygen purging. Fourteen degradation products were identified, which can be classified into three groups: phthalimide and related phthalic acid derivatives, fluorinated species related to the second amide moiety, and advanced transformation products.