Microstructure evolution in refill friction stir spot weld of a dissimilar Al–Mg alloy to Zn-coated steel

In the present study, dissimilar welds of an Al–Mg–Mn alloy and a Zn-coated high-strength low-alloy steel were welded by refill friction stir spot welding. The maximum shear load recorded was approximately 7.8?kN, obtained from the weld produced with a 1600?rev min^?1 tool rotational speed. Microstructural analyses showed the formation of a solid–liquid structure of an Al solid solution in Mg–Al-rich Zn liquid, which gives rise to the formation of Zn-rich Al region and microfissuring in some regions during welding. Exposure of steel surface to Mg–Al-rich Zn liquid led to the formation of Fe₂Al₅ and Fe₄Al₁₃ intermetallics. The presence of defective Zn-rich Al regions and Fe–Al intermetallics at the faying surface affects the weld strength.     

Ab-Initio Calculations and Thermodynamic Description of the Yb-Cd and Yb-Sn Systems

The phase diagrams of Yb-Cd and Yb-Sn systems were calculated by coupling the CALPHAD method and ab initio calculations. The enthalpies of formation of nine binary compounds (YbCd, αYbCd₂, Yb₂Sn, αYb₅Sn₃, βYb₅Sn₃, Yb₅Sn₄, YbSn, Yb₃Sn₅ and YbSn₃) were determined via ab initio density functional theory using the VASP code. Based on the available experimental data and the computed enthalpies of formation of the compounds, a thermodynamic assessment was carried out. The liquid phases and the γYb(bcc) and βYb(fcc) solid solutions were described by the Redlich–Kister polynomial model, while all the intermetallic compounds were treated as stoichiometric phases. A set of optimized model parameters were obtained for Yb-Cd and Yb-Sn systems. The calculated phase diagrams of these binary systems and their thermodynamic properties are presented and compared with the experimental data.     

High-temperature creep of alumosilicate concretes on phosphate binder

Results of high-temperature creep tests of alumosilicate concretes on a phosphate binder that consists of a mixture of electrocorundum, technical alumina, and pyrophillite are presented. The mixing liquid is H₃PO₄ and an alumochromophosphate binder. The creep tests have been performed using an installation created by BashNIPIstrom State Enterprise, which makes it possible to test three specimens in one cycle simultaneously. The experimental data on the deformation of the concretes as a function of the pressing pressure, the treatment temperature, and the test conditions (the time, the temperature, and the load) are presented. The present work is the first attempt to study the endurance of materials on phosphate binders under the joint action of high pressures and loads.     

福美双分光光度法快速测定微量铜

在碱性条件下, Ｃｕ ? 与福美双（ Ｎ Ｃ Ｈ３ Ｃ Ｈ３ Ｃ Ｓ Ｓ Ｓ Ｃ Ｓ Ｃ Ｈ３ Ｃ Ｈ３ ） 形成稳定的桔红色配合物,配合物的λｍ ａｘ ＝ ４５２ ｎ ｍ , 表观摩尔吸光系数ε＝ １ ．２ ×１０ ４ 。铜含量在０ ～１０ μｇ／ ｍ Ｌ 范围内符合比耳定律。     

Factors controlling diel patterns of methane emission via rice

Methane emissions from flooded rice grown under greenhouse conditions were monitored using a closed chamber technique. The three rice cultivars showed similar diel emission patterns though the amplitudes differed. Variation in emissions (maximum emission rate) from the different cultivars ranged from 0.164–0.241 mg/pot/h at tillering stage, 0.714–2.334 mg/pot/h at heading stage, 0.399–1.393 mg/pot/h at ripening stage. The methane emissions increased in the morning at accelerating rates, reached a maximum in the early afternoon, then decreased rapidly to constant rates during the night. The diel emission pattern was modeled using a Gaussian equation for daytime, and a constant for nocturnal emissions. Applying an Arrhenius equation, more than 90% of the diel variation of methane emissions could be predicted from soil temperature fluctuations. The predictions improved by using a diffusion model based on soil temperature and dissolved methane concentrations in soil solution. Soil temperature and methane concentration in soil solution are the two major factors controlling diel methane emissions.     

Michael addition of ethyl acrylate and acetone over solid bases

The catalytic behaviour of the superbases Na/NaOH/-Al₂O₃ and Cs_xO/-Al₂O₃ as well as of the basic zeolites Na/NaX and Cs_xO/CsX were investigated in the Michael addition of ethyl acrylate and acetone. The reactions were carried out in the liquid phase at catalyst loadings varying from 0.05 to 0.1 mol ester/g catalyst.     

Security of Water Supply and Electricity Production: Aspects of Integrated Management

The share of renewable resources in electricity generation, e.g. in Germany, is increasing. The power sector is thus becoming more dependent on climate/weather parameters. During the summer months of the last decade, numerous thermal power plants in Europe had to be throttled due to water shortages and high water temperatures. At the same time, Europe was confronted with a reduction in hydropower production. One method of securing a future electricity supply is to increase the reliability of the water supply for power plants. In this paper, scenarios are presented for future electricity production by hydropower and thermal power plants in the Elbe river basin. Electricity production in hydropower plants will decline by approximately 13 % by 2050. This decline is due to climate change and it could be compensated for by optimizing and modernizing existing hydropower plants. Due to higher efficiencies and the conversion of plant cooling systems, no water shortages are expected in most thermal power plants. However, water shortages are expected to affect the plants in the city of Berlin. Inter- and intra-basin water transfers constitute a possible adaptation option. While the transfer of water from the river Oder would be the most cost-efficient solution from Berlin’s perspective, the transfer of water from the river Elbe would have additional positive effects in the upstream Spree river sub-basin.     

水下自激脉冲射流喷嘴的吸气性能试验研究

运用自行研制的试验装置对水下不同结构参数的自激吸气脉冲射流喷嘴的吸气性能进行试验,研究了喷嘴的上下喷嘴直径、腔径和腔长等不同的组合配比对喷嘴吸气量的影响,以及喷嘴吸气量对喷嘴冲击性能的影响。结果表明:喷嘴吸气是提高水下自激脉冲射流冲击性能的有效途径,喷嘴的相对冲击力随着喷嘴吸气量的增加而提高;在较优的喷嘴结构参数配比范围内,喷嘴的吸气比率最大;最佳吸气比率的喷嘴面积比、相对腔长和相对腔径配比范围分别为3.5~4.0、8~9、11~12.5。     

Downstream Migration of the European Eel (Anguilla Anguilla) in the Elbe River,Germany: Movement Patterns and the Potential Impact of Environmental Factors

Recruitment of European eels (Anguilla anguilla) has declined to the extent that they have been added to the IUCN Red List of Threatened Species. Therefore, it is critical to ensure that eels complete their outward river migration in order to contribute to the available spawning stock. We conducted a 4‐year (2007–2011) telemetry study to understand the migratory behaviour and potential impact of environmental factors on the eel during this critical life stage. Out of 399 female eels tagged with acoustic transmitters, only 28% demonstrated clear downstream migratory behaviour. Fifty‐five percent were detected exhibiting no downstream migration behaviour and 17% were not detected at any monitoring station. Movement patterns of downstream‐migrating (silver) eels were characterized by nocturnal activity and seasonal migration, with distinct peaks in autumn and spring. Migration was often discontinuous and exhibited phases of active locomotion and expanded stopovers. The most important determinants of movement activity were water temperature, cumulative precipitation and moonlight, although the significance varied by season and location in the river basin. Our results evidence a discontinuous, stepwise migration over an extended period. Furthermore, our findings indicate that migration success depends on holding duration prior to tagging and environmental predictors with varying importance depending on the season, as well as the locations of capture, tagging and release. Copyright © 2015 John Wiley & Sons, Ltd.     

Drivers of Plant Invasion at Broad and Fine Scale in Short Temperate Streams

Riparian ecosystems have been described as highly prone to alien plant invasions; thus, disentangling the contributing factors of the invasion process is of utmost importance to conserving and managing these valuable ecosystems. In this study we examined the drivers of riparian plant invasion in 16 Cantabrian river basins (northern Spain) ranging from 100 to ca. 1050 km². A complete flora was determined for five randomly selected sites within those basins. One hundred and thirty alien plant species were found across the 80 sampling sites, representing 21% of the recorded total flora. At site scale, the level of plant invasion, measured as alien richness (AR) and relative alien richness (RAR), was assessed in relation to a set of explanatory variables by means of Generalised Linear Mixed Models. This level of invasion was influenced by environmental variables such as the thermicity index, the average riverbed width and the number of plant communities and by human‐related variables such as the distance to the nearest town and the proportion of surrounding urban land. At basin scale, industrialised river basins were more heavily invaded than non‐industrialised basins, and they both differed in their alien plant composition. Given that some of the alien species occurring in Cantabrian streams are specially abundant (Crocosmia x crocosmiiflora) and/or form very dense stands (Fallopia japonica, Paspalum distichum), future research should focus on the drivers that influence the presence and distribution of these species of special concern. Copyright © 2016 John Wiley & Sons, Ltd.