A review of the effects of pollution and water scarcity on the stream biota of an intermittent Mediterranean basin

This review presents the main results of a 10‐year research study conducted in a Mediterranean intermittent basin (Evrotas River). By assembling the main outcomes of past and ongoing research projects, this study provides an overview of multiple stressor effects, with emphasis on water scarcity, focusing on hydro‐biogeochemical processes, as well as on spatial and temporal variations in benthic macroinvertebrates and fish fauna. The major impact in the basin has been the over‐exploitation of surface and groundwater resources, which, in combination with droughts, has resulted in the recurrent artificial desiccation of large parts of the hydrological network. The response to intermittency of the macroinvertebrate fauna is characterized by high resilience through various drought‐resistant evolutionary mechanisms, with assemblages recovering successfully after recurrent droughts. However, when pollution is evident in combination with drought, effects on benthic species richness, abundance, and assemblage structure can be severe. Similarly, pollution and water stress may result in massive fish mortalities due to hypoxic conditions, with fish populations requiring long periods to recover. However, the fish fauna appears to be relatively resilient to drought‐driven reach‐scale desiccation, and ultimately recovers, provided that aquatic refugia are available to supply colonists and that there are no physical barriers impeding recolonisation. Appropriate conservation measures are urgently required to address the effects of recurrent bouts of water stress, as well as of other stressors on the freshwater communities of the Evrotas River, both at the level of water management and of water policy and at the local and the national level.     

The policy perspective for RES development in the new member states of the EU

The energy sector of the European Union (EU) is based mainly on fossil fuels and almost two-thirds of the energy demand is imported. In the future, fossil fuels are expected to strengthen their participation in the European energy balance and imports will amount to 70% of overall energy needs. On the other hand, the development of Renewable Energy Sources (RES) is a central aim of the European Commission's energy policy. RES hold a significant share in the 10 new countries recently joined the EU and the adoption of RES-related policies is of imperative importance for the joint cooperation of the new member states with the EU. This paper includes a review of RES status, related policies and prospects in each of the 10-new member states of EU.     

Effect of Ga incorporation in sequentially prepared CuInS2 thin film absorbers

Thin film CuInS₂:Ga solar cell absorber films were prepared by sequential evaporation of Cu–In–Ga precursors and sulfurization in sulfur vapor. The depth distribution of Ga was found to be highly inhomogeneous caused by CuGaS₂ phase segregation at the back contact. Depending on overall Ga content and sulfurization temperature a quaternary CuGa_xIn_1−xS₂ compound formed exhibiting a shift in absorber lattice constant and band gap. Micro Raman measurements showed that crystal quality was also affected by Ga. Open-circuit voltages well above 800 mV were achieved while sustaining high fill factors of 71%.     

Nonconvex Optimization: Gradient Flows and Deformation

In this survey paper we consider two features in finite dimensional smooth nonconvex optimization problems. The first one is concerned with global aspects of gradient flows. The second part is devoted to one-parametric families of optimization problems. Here, the index set corresponding to inequality constraints might be infinite and might depend on the state variable, too.     

Comprehensive handbook of ternary alloy phase diagrams

A program for critical and systematic evaluation of existing ternary alloy phase diagram information by Max-Planck-Institut für Metallforschung, and Alan Prince of the Alloy Phase Diagram Data Committee of the Metals Society, is described. The resulting diagrams and supporting text are planned for publication by Gmelin Institut für Anorganische Chemie und Grenzgebiete as a multi-volume handbook. Described are the procedures to be followed during evaluation and the format to be used for each presentation.     

Energieautonomer Funknetzwerkknoten für Luftfahrzeuge

Energieautonome Funknetzwerkknoten sind die Grundlage für vielf?ltige überwachungsaufgaben, die drahtlos übernommen werden k?nnen. Ein Sensornetzwerk ist in der Lage, überwachungsaufgaben kosteneffizient zu übernehmen, wenn Ma?nahmen zur Energieversorgung wegfallen. Daher ist dieser Ansatz für die Luftfahrtindustrie interessant, um z. B. die Flugzeugstruktur hinsichtlich Sch?den zu überwachen. Für energieautonome Aufgaben ist einerseits der Energieverbrauch des Funksensorknotens wichtig und andererseits die Verfügbarkeit einer regenerativen Energiequelle. Zudem wird ein effektives Energiemanagement ben?tigt, das die regenerativ gewonnene Energie in einen für den Sensor geeigneten Parameterbereich umwandelt. Im Folgenden wird ein solches System für den Einsatz in Luftfahrzeugen vorgestellt, bestehend aus Funksensorknoten, Energieverwaltungseinheit und einer regenerativen Energiequelle. Der Schwerpunkt liegt hierbei auf der regenerativen Energiequelle, welche auf einem thermoelektrischen Generator (TEG) beruht, der sich die wechselnden Temperaturen in der Flugzeugstruktur bei Start und Landung zunutze macht. Eine Seite des thermoelektrischen Generators wird der sich ?ndernden Umgebungstemperatur ausgesetzt, w?hrend die andere mit einer W?rmekapazit?t verbunden wird. Durch diesen Ansatz wird ein Temperaturgradient am TEG erzeugt und über den Seebeck-Effekt eine autonome Energiequelle geschaffen. Das Gesamtsystem wurde in einer Klimakammer getestet, und die ersten Ergebnisse sind vielversprechend.     

华北平原东部水资源可持续利用

华北平原东部水资源短缺,深层地下水严重超采,生态环境恶化。为水资源的可持续利用,要发展井灌井排、渠灌沟排,以开发利用当地浅层地下水包括微咸水和咸水为基础,以引调可利用的地表水补源,以调控地下水埋深在临界动态为核心,以土壤及潜水的地层空间作为调节大气降水、土壤水、地下水、地表水的地下水库,最大限度地把时空分布不均的天然降雨转化为可持续利用的水资源。     

Development of a vertical gradient freeze process for low EPD GaAs substrates

The main characteristics of low EPD 4 in semi-insulating and Si-doped conductive GaAs single crystals grown by a proprietary low thermal gradient vertical gradient freeze (VGF) technique on an industrial scale are presented.