Effects of Lap Configuration on Mechanical Properties and Composition Distribution of Three-layer Overlapped Laser Weldments on Al/Cu Dissimilar Materials

Battery cells are connected via bus-bars to meet performance requirements, such as power and capacity, and multiple layers of dissimilar materials functioning as anodes, cathodes, or bus-bars are overlapped and welded together. In laser welding, the formation of brittle intermetallic phases in the weld joint is inevitable and, in turn, deteriorates the mechanical properties. To obtain the desirable joint performance, appropriate welding parameters to avoid intermetallic phase formations and joint designs to release stress concentrations must be obtained. This study investigates the effects of lap configurations and process parameters on the tensile-shear load, T-peel load, and composition distribution when multi-layered joints of dissimilar materials are produced by laser welding. Two layers of 0.4 mm Al sheets were welded with a single 0.2 mm Cu sheet, which was emulated using electric vehicle battery interconnects. The results show that the penetration depth varied in accordance with the lap configuration even under the same heat input condition. The lap configuration and welding parameters influenced the composition distribution of the welds, as they altered the solidification rate, number of Cu/Al contact interfaces, and location of the high-density material. The failure load of the T-peel specimens was always lower than that of the tensile-shear specimens except for the Cu−Al−Al lap configuration. The T-peel load of the Cu−Al−Al lap configuration was similar to that of the tensile-shear load. When the stress-concentrated joint was homogeneous, it was more robust.

New records and range extensions to the Costa Rican freshwater fish fauna, with an updated checklist

The knowledge of the Costa Rican freshwater fish fauna continues to grow given the discovery of new taxa, the recognition of taxa resurrected from synonymy and the corroboration of new country records and new range extensions. Moreover, recent advances in the understanding of the phylogenetic relationships and status of many supraspecific groups have led to numerous taxonomic and nomenclatural changes. Given this, the purpose of this paper is to update the known composition, distribution and clasification of the Costa Rican freshwater fish fauna taking as reference the most recent list for the country published by Angulo et al. (2013). A total of 23 new country records (i.e., species; distributed in 17 families and 21 genera), 33 new range extensions (distributed in 20 families and 30 genera) and several nomenclatural changes are reported, illustrated and discussed here. An updated and annotated checklist of the freshwater fishes of the country (including data for a total of 283 species, 13 of which are exotic, distributed in two classes, 27 orders, 55 families and 136 genera) is also provided.

Distribution and diversity of gelatinous zooplankton in the southern South China Sea

Although gelatinous zooplankton are widely distributed in many ocean ecosystems, they have been understudied due to their fragility nature, difficulties to sample or handle and a lack of expertise. This study gives an insight into the distribution and diversity of gelatinous species in the Southern South China Sea. Species composition, distribution and abundance of gelatinous zooplankton were investigated along the East Coast of Peninsular Malaysia. A total of 37 species were recorded from 10 locations along 4 transects at 5.10° N and 6.80° N extending from 103.2° E to 105.3° E in August 2016. Seven medusae, six siphonophores, four appendicularians, six chaetognaths, six salps, four doliolids and four pteropods were identified from the study area. Appendicularia with 201 ind/m3 was found to be the most dominant taxa recorded, followed by chaetognaths with 197 ind/m3. Scyphomedusae were the least represented group in the study, with an abundance of 8 ind/m3. Stations near the inshore region show higher abundance and diversity of gelatinous zooplankton compared to offshore regions. The evenness index between stations revealed that the gelatinous zooplankton were evenly distributed. According to Principal Component Analysis (PCA), the diversity and distribution of gelatinous zooplankton are driven by depth and temperature.

Inferring Shallow Surfaces on Sub-Neptune Exoplanets with JWST

Planets smaller than Neptune and larger than Earth make up the majority of the discovered exoplanets. Those with H2-rich atmospheres are prime targets for atmospheric characterization. The transition between the two main classes, super-Earths and sub-Neptunes, is not clearly understood as the rocky surface is likely not accessible to observations. Tracking several trace gases (specifically the loss of ammonia (NH3) and hydrogen cyanide (HCN)) has been proposed as a proxy for the presence of a shallow surface. In this work, we revisit the proposed mechanism of nitrogen conversion in detail and find its timescale on the order of a million years. NH3 exhibits dual paths converting to N2 or HCN, depending on the UV radiation of the star and the stage of the system. In addition, methanol (CH3OH) is identified as a robust and complementary proxy for a shallow surface. We follow the fiducial example of K2-18b with a 2D photochemical model on an equatorial plane. We find a fairly uniform composition distribution below 0.1 mbar controlled by the dayside, as a result of slow chemical evolution. NH3 and CH3OH are concluded to be the most unambiguous proxies to infer surfaces on sub-Neptunes in the era of the James Webb Space Telescope.

Theoretical analysis of the factors, influencing composition uniformity of the cadmium zinc telluride substrates grown by THM

The effect of the sample composition, variation of the temperature field and the feed material non-homogeneity on uniformity of the growing crystal is considered. It is shown that optimization of the solvent composition makes it possible to minimize the jump of the ZnTe concentration at the seed/crystal boundary. The composition fluctuations at variation of the thermal field during crystal growth are smooth enough and relatively non-significant. The feed composition distribution has, as a rule, a random character. Different harmonics of composition distribution non-uniformity in the feed material differently affect the homogeneity of the growing crystal. Longwave non-uniformities in the feed transform into the growing crystal almost completely. At the wavelength equals to a half of the solvent length or shorter, the perturbations of the growing crystal composition are relatively small. Evidently, the cause of the local composition variations, found in real crystals, is, basically, the feed composition non-uniformities

Overview of the range of medicinal extracts at the pharmaceutical market of Ukraine

Aim. To study the range of medicinal extracts at the pharmaceutical market of Ukraine as of 2020 in order to determine the feasibility of developing a new medicinal product based on them.Materials and methods. The bibliosemantic, analytical, logical research methods were used to analyze the literature sources; the analytical analysis was applied to study the segment of the domestic pharmaceutical market regarding the range of medicinal extracts as of 2020. Thus, their composition, distribution by the aggregate state, forms of production and country of origin, harmonization with the Ph. Eur. were analyzed.Results. It has been determined that the domestic pharmaceutical market has 18 extracts, all of them are liquid. Among all extracts registered in Ukraine the leading place (16 items) belongs to the Ukrainian manufacturers. The nomenclature of imported drugs consists of 1 extract of Vietnamese and 1 of Swiss production. Among the Ukrainian manufacturers, the largest market segment belongs to PJSC “Lubnipharm” ‒ 4 drugs; “Rotokan” is available in 55 and 110 ml bottles, while “Aloe extract”, solution for injection, 1 ml, No. 10, in ampoules is produced by PJSC “Lubnipharm” and CJSC “Darnytsia”; “Eleutherococcus extract”, 50 ml, in a bottle ‒ by LLC “Unipharma” (“Ternopharm”) and agricultural firm “Yan”. There are 19 drugs with extracts at the domestic pharmaceutical market; among them the largest market segment is occupied by drugs in the form of tablets and capsules (7 items), 2 oral solutions, 1 drug in the form of oral drops, 1 syrup and powder for oral solution. Most drugs containing extracts are made by the Ukrainian manufacturers (about 47 %), while manufacturers from Germany, France and Switzerland supply 2 drugs each, Spain, Bulgaria, Slovenia and the Czech Republic ‒ 1 drug each.Conclusions. There are 18 extracts and 19 preparations with extracts at the pharmaceutical market of Ukraine. Most of the drugs in this sample are hypnotics and sedatives (55 %), as well as drugs used in diseases of the liver and biliary tract, they improve digestion and the functional state of the gastrointestinal tract.

Phase Behavior and Composition Distribution of Multiphase Hydrocarbon Binary Mixtures in Heterogeneous Nanopores: A Molecular Dynamics Simulation Study

In this study, molecular dynamics (MD) simulation is used to investigate the phase behavior and composition distribution of an ethane/heptane binary mixture in heterogeneous oil-wet graphite nanopores with pore size distribution. The pore network system consists of two different setups of connected bulk and a 5-nm pore in the middle; and the bulk connected to 5-nm and 2-nm pores. Our results show that nanopore confinement influences the phase equilibrium of the multicomponent hydrocarbon mixtures and this effect is stronger for smaller pores. We recognized multiple adsorbed layers of hydrocarbon molecules near the pore surface. However, for smaller pores, adsorption is dominant so that, for the 2-nm pore, most of the hydrocarbon molecules are in the adsorbed phase. The MD simulation results revealed that the overall composition of the hydrocarbon mixture is a function of pore size. This has major implications for macro-scale unconventional reservoir simulation, as it suggests that heterogenous shale nanopores would host fluids with different compositions depending on the pore size. The results of this paper suggest that modifications should be made to the calculation of overall composition of reservoir fluids in shale nanopores, as using only one overall composition for the entire heterogenous reservoir can result in significant error in recovery estimations.