Determination of Area-Averaged Water Vapour Fluxes with Large Aperture and Radio Wave Scintillometers over a Heterogeneous Surface – Flevoland Field Experiment

A large aperture scintillometer (LAS) andradio wave scintillometer (RWS)were installed over a heterogeneous areato test the applicability of the scintillation method.The heterogeneity in the area, whichconsisted of many plots, was mainly caused bydifferences in thermal properties ofthe crops; the variations in theaerodynamic roughness lengthwere small. The water vapour fluxesderived from the combined LAS-RWSsystem, also known as the two-wavelengthmethod, agreed fairly well with the aggregatedwater vapour fluxes derived from in-situeddy covariance measurements. The water vapourfluxes derived from a stand-alone LASare also presented. It was found that a single LASand an estimate of the area averagedavailable energy (using a simple parameterisationscheme) can provide also reasonablearea-averaged water vapour fluxes.     

Validation of Landslide Susceptibility Maps; Examples and Applications from a Case Study in Northern Spain

A procedure for validating landslide susceptibility maps wasapplied in a study area in northern Spain and the results obtained compared. Validationwas used to carry out sensitivity analysis for individual variables and combinationsof variables. The validity of different map-making methods was tested, as well as theutility of different types of Favourability Functions. The results obtained show thatvalidation is essential to determine the predictive value of susceptibility maps. Italso helps to better select the most suitable function and significant variables, thus improving the efficiency of the mapping process. Validation based on a temporal strategy makes it possible to derive hazard maps from susceptibility maps.     

THE RETREAT OF THE FOREST IN SOUTHEAST ASIA: A CARTOGRAPHIC ASSESSMENT

Rapid deforestation is a major problem throughout the tropical world. The conditions and the pace under which societies and economies of the Third World are currently evolving and growing, combined with the specificities of tropical forests, render the latter increasingly vulnerable. Among the major tropical areas of the world, Southeast Asia is perhaps the one where these conditions have had the most impact on the retreat of the forest cover over the last quarter of this century. This is illustrated through the presentation of two maps of the distribution of five basic forest formations in Southeast Asia circa 1970 and circa 1990. The maps are examined and compared, as well as confronted with statistical assessments of deforestation. Finally, the complex causes behind the retreat of the tropical forests as well as the implications of this retreat are briefly discussed.     

Primary minerals of Zn-Pb mining and metallurgical dumps and their environmental behavior at Plombières,Belgium

The primary phases and minerals of the Plombières dumps include typical smelting furnace products such as metallic Fe, Pb, Cu, Zn, Fe-Zn alloys, carbides, phosphides, sulfides of Fe, Zn, Pb, Cu, Mn (alabandite), and FeAs. Spinels, mainly of Fe and Al, are common constituents of the primary assemblage; substitution by Zn, V, Cr, Ti, Mg, and Ca occurs. Primary phases also include the most common Zn-rich fayalite, Zn-rich Ca-Fe silicates, melilite, corundum, and apatite. Most of the Zn is incorporated in iron silicates, ZnO and ZnS. Lead occurs mainly as PbS, metallic lead, and is also present in coal residues. Cadmium is found mainly in metallic zinc and its alloys and in ZnO. The dumps also contain mining wastes composed of pyrite, melnikovite, and iron oxides produced by natural weathering of Zn-Pb ores. Melnikovite and iron oxides are rich in As, Pb, and Zn and possess an increased content of Tl. Leaching tests carried out on the surfaces of polished sections indicate that acid rain (solutions I and II) will mobilize mainly Zn and Cd and, to a much smaller extent, Pb and Sb. Leaching of metals by sulfate-chloride fluids present in the pore network of dumps (solutions III, IV, and V) depends on the pH, which in the dumps is controlled by the proportion of carbonates to sulfides. The more acid fluids leach both sulfides and silicates.     

鱼塭产斑节对虾(Penaeus monodon)催熟繁殖技术研究

以综合催熟措施和移植精荚手术相结合的技术方法,解决了鱼塭产斑节对虾催熟效应期长,产卵率低,易蜕壳失去精荚等难题。使用 ２７８ 尾雌虾,催熟率达９０％ 以上,在４０ ｄ 内共产卵６０８ 尾次,卵量１８ ５３０ 万粒,孵出无节幼体１１ ９９８ 万尾,平均孵化率 ６４．７％ ,平均每尾雌虾孵出无节幼体 ４３．１ 万尾,育成商品虾苗 １ ０２８．５ 万尾,育苗平均成活率 １３．６％ ,试养成活率５７．１％     

Electrochemical technique for exploration of base metal sulphides

A method based on the principles of electrochemistry has been applied for the first time with indigenous equipment in the search for base-metal sulphides, following a field exploration technique known as ‘CHIM — 10’, which is in use in the U.S.S.R. for the last few years. The technique utilizes the electro-positive property of the metallic ions. When a large section of the ground is artificially electrolyzed by the introduction of a direct current, the metallic ions within the moist soil profile close to the mineralized zone tend to move towards the energizing cathodes of a powerful widely spaced electrode array. A laboratory model experiment was conducted first which showed encouraging results. Subsequently, a prototype field unit was fabricated and employed to examine its effectiveness in the field on a soil profile over the base-metal sulphide zones of Aladahalli area, Hassan District, Karnataka, where the geology of the deposit is well known.The results obtained during the field trials were quite good and in full conformity with the known geology. However, detailed evaluation of those data after applying necessary corrections for the different variable parameters of the system is yet to be done. Work is in progress to refine the technique with a view to standardizing and developing its use for qualitative and quantitative assessment of a concealed base-metal deposit in a given area, specially where conventional geochemical exploration methods are not suitable.The paper deals with the details of the technique and discusses the results obtained during the trial run in the field.     

Principal Components Analysis of Rainfall and Associated Synoptic Models of the Southwest Monsoon over India

Summary  The summer monsoon circulation shows various spatial and temporal oscillations and often a combination of systems produces an integrated effect. In this study phases of the southwest (SW) monsoon have been identified in an objective manner with the help of T-mode principal component analysis (PCA) of weekly rainfall anomalies. Mean composite charts have been prepared utilising all available upper air data (1977–1986) for each category of the SW monsoon epochs identified by the PCA. These sets of charts have been constructed for both the strong and weak phases associated with the first four significant principal components (PCs). A well defined east-west oriented trough system, extending from about 28° N Latitude/65° E Longitude to 20° N Latitude/90° E Longitude, in the lower levels, has been the main feature associated with the strong phase of the monsoon corresponding to PC I. The trough in the lower levels is more marked in the eastern half compared to the western half in both the sets of charts associated with strong phases of the monsoon related to the PC II and PC III. With PC II, the position of the troughs in the lower levels is further north of its location in PC III. The east-west trough system associated with the strong phase of PC IV has a large southward tilt with height. The charts corresponding to the weak phases of these PCs have synoptic features, such as the position of the trough close to the foothills of the Himalayas, and the shifting of middle and upper tropospheric anticyclones to the south. The study suggests an objective method of interpretation of principal components by utilising synoptic data. In addition, synoptic models and data sets corresponding to different phases of the monsoon can also be prepared in an objective manner by such PCA. Received July 18, 1997 Revised April 30, 1999     

Vertical behaviour and meteorological properties of air masses in the southwest of the Iberian Peninsula (1997–2007)

Air masses are characterized by physical (temperature, humidity) and chemical (transported gases and aerosols) properties, being associated their arrival to different meteorological scenarios. The knowledge of the air masses over a region is fundamental as complementary information in several atmospheric studies, being the calculation of back-trajectory the most widely used tool whenever air masses are analyzed. A study of air masses has been carried out in southwestern Iberian Peninsula using 5-day kinematic back trajectories computed by the HYSPLIT model at three heights (500, 1,500 and 3,000 m) from 1997 to 2007. The main aims have been to characterize their vertical behaviour and their thermal and humidity properties. Thirteen trajectory clusters have been defined, showing the northerly and westerly clusters a high coupling degree. Seasonal daily variation of potential temperature and specific humidity has been analyzed, obtaining higher differences among clusters in the cold season.     

基于循环孔洞扩张模型的X型圆管节点超低周疲劳寿命预测

海洋工程钢结构在服役过程中,受风、浪、流或地震等极端循环载荷的影响,易发生超低周疲劳断裂破坏,造成人员伤亡及财产损失,因此超低周疲劳断裂分析及寿命预测对于海工结构安全性评估至关重要。然而,现阶段基于累积损伤理论提出的多种超低周疲劳寿命预测模型无法对多尺度节点实现统一预测,造成了实际工程应用的不便。因此文中基于循环孔洞扩张模型开展X型圆管节点超低周疲劳寿命预测。首先,开发了基于循环孔洞扩张模型的VUSDFLD程序,实现ABAQUS与FORTRAN子程序联合应用,利用有限元分析验证循环孔洞扩张模型在X型圆管节点超低周疲劳断裂分析中的有效性;其次,根据多组X型圆管节点超低周疲劳断裂有限元分析结果,在宏观层面提出了一种基于Manson-Coffin公式的超低周疲劳寿命预测公式;最后,依据Miner理论,将适用于等幅加载的超低周疲劳寿命公式扩展至变幅加载情况,验证了多种节点尺寸下超低周疲劳公式的适用性,为工程应用提供了理论依据。