Hydrogeographical Regionalisation: An Approach for Evaluating the Effects of Land Cover Change in Watersheds. A Case Study in the Cuitzeo Lake Watershed, Central Mexico

Efficient natural resources management, including continental water at watershed level, requires understanding the arrangement of landscape attributes in a region. The geographical analysis of landscape attributes is a useful approach to delineate relatively homogeneous watersheds or regions. This research was carried out in order to evaluate the effect of land cover through time on regionalisation modelling in the poorly-gauged Cuitzeo Lake Watershed, and to develop models to create two hydrogeographical regionalisations for the years 1975 and 2000. The inputs required by the regionalisation methodology were integrated in a GIS and validated before carrying out statistical regionalisation procedures (cluster analysis and PCA). GIS operations were done in Arc View 3.2 and statistical analyses in PC-ORD. Median Euclidean distances with mean distance linkage methods were used. A 75% of similarity was chosen as the threshold to generate regions. Importance rankings of regions were obtained using multicriteria evaluation methods. Based on the analysis, 38 of the 52 subwatersheds belonging to the Cuitzeo Lake Watershed were clustered; eight groups were defined in 1975 and nine in 2000. According to PCA, the strongest positive variables are associated to morphometric, geologic, land cover and soil attributes. Fourteen subwatersheds were never clustered. Four subwatersheds changed of cluster between 1975 and 2000. This change is explained because of rainfed agricultural parcel abandonment, and subsequent shrubland growth. This means that the hydrogeographical regionalisation is sensitive to land cover change processes. The methodological approach applied in this research is a low-cost and fast alternative for evaluating the impact of land cover and land use change on hydrogeographical regionalisation; in consequence, data and information generated during the analysis were made available to local authorities so that they can improve both water resources planning and their informational baseline for decision making and for development of environmental policies in the Cuitzeo Lake Watershed.     

顶部籽晶熔渗法单畴YBCO的制备及其显微结构分析

采用顶部籽晶熔渗工艺(Seeded infiltration and growth technique简称SIG)成功制备出了单畴的YBCO超导体,并对样品的显微结构进行了分析。整个SIG样品的超导相显微组织比较均匀,Y123片层的厚度很薄且连接性很好,但Y211粒子在样品中的分布并不均匀,如相对于c-GS区域而言,a-GSs区域Y211粒子的浓度较大且平均尺寸较小,这种不均匀性与Y211粒子的尺寸有关。本文比较详细的讨论了影响顶部籽晶熔渗法制备单畴YBCO超导体显微组织的因素。     

Analysis of high contact resistance in silver impregnated graphite (SIG) contacts

Silver impregnated graphite (SIG) contacts are used in high safety applications of railway signaling, traffic signaling, and numerous other applications due to high silver content that eliminates the risk of welding in the presence of graphite. High contact resistance (>200 mΩ) was observed in SIG contacts in a railway signaling operation after a few thousand operations of the relay. The high contact resistance was discovered to be a result of loose dust/foreign particles residing between the two contacts. Silver had been preferentially removed from the contacting surfaces during switching operations by an abrading effect of the dust/foreign particles, leaving only graphite on the contact area. Wear was accentuated by the presence of porosity and low hardness of the contacts, leading to improper interaction between the mating surfaces.     

Kinetics of nucleation and growth of L-sorbose crystals in a continuous MSMPR crystallizer with draft tube: Size-independent growth model approach

The experimental data concerning kinetics of a continuous mass crystallization in L-sorbose - water system are presented and discussed. Influences of L-sorbose concentration in a feeding solution and mean residence time of suspension in a working volume of laboratory DT MSMPR crystallizer on the resulting crystal size distributions, thus on the nucleation and growth kinetics, were determined. The kinetic parameter values were evaluated on the basis of size-independent growth (SIG) kinetic model (McCabe’s ΔL law). It was observed that within the investigated range of crystallizer productivity (220–2,200 kg of L-sorbose crystals m⁻³ h⁻¹), a crystal product of mean size Lm from 0.22 to 0.28 mm and CV from 68.8 to 44.0% was withdrawn. The values of linear growth rate show increasing trend (from 6.6·10⁻⁸ to 7.6·10⁻⁸ m s⁻¹) with the productivity enlargement (assuming constant residence time τ=900 s). Occurrence of secondary nucleation phenomena within the circulated suspension, resulting from the crystals attrition and breakage was observed. The parameter values in a design equation, matching linear growth rate and suspension density with nucleation rate were determined.     

蓝牙资格认证解析

蓝牙资格认证要求所有使用蓝牙标准的设计和产品都要符合测试标准。介绍了蓝牙的认证流程,包括产品概念、测试计划、产品测试和产品列表;并且针对于不同的产品,从测试、文档、评估、声明、列表、标识、符合稽查和强制要求方面介绍了应满足的蓝牙认证要求。     

Désavantage socioéconomique du quartier et comportements antisociaux des adolescents: Quelle est l'échelle spatiale la plus probante?

Over the past two decades, a significant number of studies in the United States, Canada and Europe have attempted to identify links between neighbourhood characteristics and antisocial behaviour of children and adolescents. Despite the abundance of work, the question of the choice of spatial scale has received little attention. Indeed, few studies have used different scales simultaneously in order to identify the most relevant scale. The aim of our study is precisely to identify the spatial scale in the most convincing explanation of antisocial behaviour violent and nonviolent in mid-adolescence and to better understand whether these are the characteristics of the immediate social environment at home or those of a much larger space that best explain the frequency of these behaviours. Using data from the a Montreal longitudinal study (ELEM) for 1037 boys from neighborhood socioeconomically disadvantaged, we tested the influence of different spatial scales defined from buffer zones (5, 10, 15, 20 and 30 minutes walk) from the residence of the child. The results show a significant relationship between low socioeconomic area and violent behaviour regardless of the spatial scale used. However, this relationship is significantly stronger for the smaller spatial units. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mechanism of seeded infiltration growth process analysed by magnetic susceptibility measurements and in situ observation

Using the magnetic susceptibility measurements (MSM) at high temperature and in situ video observation, the mechanism of seeded infiltration growth (SIG) process was investigated. This process offers the opportunity to verify the main phase transition by measuring the magnetic force acting on the sample. The heat treatment process which adjusted from MSM and video observation, allows to obtain the single domain YBCO superconductor.     

SIG框架基于多线程技术分布式系统的任务调度

空间信息网格是利用网格技术实现空间信息资源的共享、管理和提供空间信息服务的系统和各种的空问信息服务的基础设施，任务调度是分布式系统和网格系统最具有挑战的问题之一，Java语言里的多线程机制很好地解决了这一问题。该文主要研究了SIG中的任务调度技术，通过实验确定分布式系统里的线程数目，使系统性能获得局部最优。     

Continuous reaction crystallization of struvite from diluted aqueous solution of phosphate(V) ions in the presence of magnesium ions excess

Continuous reaction crystallization of struvite MgNH₄PO₄·6H₂O from diluted aqueous solution containing phosphate(V) ions of concentration 0.20 wt% PO₄³⁻ was investigated experimentally. The tests were carried out in a continuous DT MSMPR type crystallizer in temperature 298 K assuming 20% excess of magnesium ions at the inlet point in respect to struvite synthesis reaction stoichiometry. Influence of pH (8.5–10) and mean residence time of suspension in a crystallizer (900–3600 s) on the product crystals size distribution, their size-homogeneity and process kinetics were identified. Crystals of mean size from ca. 19 to ca. 73 μm, of diverse size-homogeneity (CV 60–87%) were produced. Struvite particles of the largest sizes and acceptable homogeneity were produced at pH 8.5 for prolonged mean residence time 3600 s. Under these conditions struvite nucleation rate did not exceed 5.3 × 10⁷ l/(s m³) according to SIG MSMPR model predictions. Crystal linear growth rate within the investigated process parameter values varied from 3.62 × 10⁻⁹ to 1.68 × 10⁻⁸ m/s. Magnesium ions excess in a process environment influenced yield of continuous reaction crystallization of struvite advantageously – contrary to product crystals quality. Concentration of phosphate(V) ions in mother solution decreased from inlet 0.20 wt% to 0.9 × 10⁻³ – 9.2 × 10⁻³ wt% (9–92 mg/kg) depending on pH and mean residence time of suspension in a crystallizer, what can be regarded as a very good result of their recovering from solution.     

基于Agent的空间信息网格系统

空间信息网格(SIG)是一种具有按需服务能力的空间信息基础设施。该文提出将Agent技术应用于构建空间信息网格体系结构,包括三层:用户/应用层、Agent服务层、信息层。不同的应用经由Agent服务得到各自所需的空间信息,Agent服务为用户访问、处理空间信息提供完全透明的服务,并对该体系结构的执行结果进行讨论。