Reliability Evaluation of Cu-Al WB in High Temperature and High Current Applications

High reliability harsh environment applications necessitate a better understanding of the acceleration factors under operating stresses. Automotive electronics has transitioned to the use of copper wire for first level interconnects. A number of copper wire formulations have emerged including palladium coated copper and gold-flash palladium coated copper. The corrosion reliability of copper wire bonds in high temperature conditions is not yet fully understood. The EMC used to encapsulate chips and interconnects can vary widely in formulation, including pH, porosity, diffusion rate, composition of contaminants and contaminant concentration. To realistically represent the expected wirebond reliability, there is need for a predictive model that can account for environmental conditions, operating conditions, and exposure to EMCs. In this paper, different EMCs were studied in a high-temperature-current environment with temperature range of 60°C–100°C under current of 0.2A–1A. The diffusion kinetics based on the Nernst-Planck Equation for migration of the chlorine ions has been coupled with the Butler-Volmer equation for corrosion kinetics to create a Multiphysics model. Polarization curves have been measured for copper, aluminum and intermetallics under a number of pH values, and chlorine-ion concentrations. Tafel parameters have been extracted through measurements of the polarization curves.

Anthropogenic рollution of the coastal zone and hydrochemical analysis of the waters of Lake Baikal within the borders of the Republic of Buryatia

Anthropogenic impact on Lake Baikal is currently a big problem for the world community as a whole. Its solution depends on a number of factors, the main of which is the assessment of the level of impact and its maximum reduction. According to various researchers, a gradual accumulation of a number of chemical elements occurs in the waters of Lake Baikal, which leads to a change in the ecosystem as a whole. The purpose of this work was to assess the state of the coastal zone and to assess the hydrochemical regime of the coastal zone of the northeastern coast of Lake Baikal. According to the results of the observations, the coastal zone of Maximikha and Oymur villages is the most polluted, where a large amount of rotting algae was observed, as well as anthropogenic pollution. The least polluted is the coastline about c. Ust-Barguzin. According to the results of the study of physical indicators of Lake Baikal water, the achievement of the upper limit of the MPC in terms of color in the water samples of the Dulan ulus in the summer of 2020 and in the spring of 2021, as well as in the spring in the water samples of the village of Sukhaya was found. In addition, the turbidity index of the water near the Dulan ulus in the spring period was 2 EMF, which is also on the border of the norm. According to the results of the study of chemical parameters of water, the pH at most points is slightly alkaline, the water hardness at all stations did not exceed 3°. The total alkalinity of water at all stations ranged from 92.8 to 23.2 mg-eq/dm³. The ion content of various substances does not exceed the values established by other authors for oz. Baikal is: dissolved oxygen (O₂) — from 6 to 12 mg/dm³, chlorine ions (CL⁻) — from 0.1 to 0.5 mg/dm³. The value of permanganate oxidizability is 2 mg/dm³.

Numerical Investigation for The Valorization of Waste from HMD Cell Using Electrodialysis

The Hydromagnetic desalination (HMD) system is a continuous process with several advantages, including a high water recovery ratio, and can be favored economically by producing several industrial byproducts instead of discharging the highly concentrated brine to the environment. In the current work, the ions concentration in the Electrodialysis (ED) technique is simulated using COMSOL Multiphysics V.5.2 software. The ED cell simulated in this paper contains two selective membranes (anion and cation) with a width of 0.25 mm each. The salt is to be taken away in the middle domain. The cell operation has been simulated to separate the sodium and chlorine ions from the HMD brine waste solution at 40 or 55ºC temperatures at different voltages and concentrations. In this two-dimensional model, the Nernst-Plank equation has been used to describe ion flux and charge transport in the electrolyte solution. Secondary current distribution theory and the electroneutrality condition have been used in the mathematical model. Finally, Donnan equations have been used to provide the exact fulfillment of boundary conditions for constant voltage mode. The simulation shows that the highest efficiency is obtained at high temperatures and voltage with the lowest feed concentration. Finally, the results have been validated using experimental data from the literature, and a satisfying agreement has been found.

Investigation of granulometric, chemical and phase compositions of hot‑dip galvanizing wastes

The article presents the waste generated during the production of hot‑dip galvanizing. The results of the study of the particle size distribution of zinc dust showed that its particle size distribution in the size range of particles ≤ 250 μm, the proportion of which is 87 wt.%, corresponds to the fractional composition of standard powder zinc. In ash, the number of particles up to 250 microns in size is approximately 35 wt.%. Studies of the chemical and phase composition of the hot‑dip galvanized waste – zinc dust made it possible to establish that the zinc content of the waste approximately corresponds to powder zinc (GOST 12601). The proportion of pure zinc in dust is 95 %. Chemical and phase analyzes of the ash have shown that it contains zinc oxides, pure zinc and zinc chlorides. Zinc chlorides, in turn, can be a supplier of chlorine ions in thermal diffusion galvanizing. In this regard, it is of interest to use ash in the composition of the powder composition as an activating and zinc‑containing component. The results of the analysis of the conducted studies of hot‑dip galvanizing wastes – zinc dust and soot show that they are promising for their use as components in saturating mixtures in the production of zinc coatings by chemical‑thermal treatment. This will reduce the cost of galvanized products and ensure the recycling of zinc into industrial circulation.

Characteristics of reproductive parameters and quality of sexual products of female carp (Cyprinus carpio (Linnaeus, 1758)) when feeding them with hulless oat during prespawning period

Purpose. To investigate the effect of feeding carp with hulless oat during pre-spawning period on the reproductive functions of female carp as well as on qualitative characteristics of the obtained eggs. Methodology. The objects of the study were females of the Nyvky intra-breed type of the Ukrainian scaly carp breed, which were kept during the pre-spawning period in pond conditions of the State Enterprise “Nyvka” of the Institute of Fisheries NAAS of Ukraine. Females were divided into 3 groups. The first group (Experiment I) was fed with 30% hulless oat, the second (Experiment II) with 100% hulless oat. The control group of fish (Control) was fed with a grain mixture. Experiments were conducted in accordance with current methods used in aquaculture. The mass fraction of protein was determined by the Kjeldahl method, the fat content was determined by S.V. Rushkovsky method. Determination of total lipids was performed by the Folch method. Sampling of water for chemical analysis and its processing in the laboratory was carried out according to O.A. Alokin method according to the Standard of the Ministry of Agrarian Policy of Ukraine. Analytical processing of the material was performed using MS Excel. The criteria for the analysis of studied parameters were their mean values (M) and standard deviations (m). Results. According to studies, the use of 30% hulless oat in the feed of female carp during the pre-spawning has a positive effect on their production of eggs, as evidenced by an increase in relative fertility by 15.6%, fertilization rate by 4.0%, and survival of the obtained 3-day-old larvae by 5.0%. According to biochemical parameters of eggs, there was an increase in the amount of essential amino acids by 3.04 and 2.01 g/100 g of protein, and fractions of lipids responsible for energy storage, in particular triglycerides, by 11.56 and 5.62%, phospholipids by 3.65 and 2.37%, and fatty acids by 5.33 and 3.11%, respectively, according to the experimental groups. Instead, cholesterol levels decreased by 13.4 and 25.2%. Temperature, oxygen, and hydrochemical regimes in the hatchery were within aquaculture standards, except for permanganate oxidation and total iron and chlorine ions. Originality. The prospects of using hulless oat in feeding brood carp were studied in Ukraine for the first time. The analysis of reproductive parameters of female carp as a result of experimental feeding and evaluation of the qualitative characteristics of eggs and offspring obtained by the method of factory reproduction was conducted. Practical value. The results of a comprehensive assessment of aquaculture and biological parameters will provide recommendations for the use of hulless oat in feeding female carp during pre-spawning period. Key words: carp, feeding, hulless oats, reproductive parameters, survival, amino acid and lipid composition of eggs.

Cleavage-dissolution assisted stress corrosion cracking under elastic loads

As a significant cause of disastrous accidents, stress corrosion cracking (SCC) under elastic loads was investigated in type 316 L single-crystal stainless steel immersed in a boiling 45 wt% MgCl2 solution. Three-dimensional microcrack morphologies, characterized using synchrotron-based X-ray computed tomography, indicate that the SCC advanced along the cleavage planes (1 0 0) with the lowest free surface energy. The first-principles simulations show that synergistic adsorption of H and Cl atoms in the octahedral interstices minimized the surface energy of the cleavage planes (0 0 1) owing to a 73% reduction. Afterwards, the cleavage-dissolution mechanism is put forward, proposing that the SCC essentially originates from preferential brittle rupture of the corrosive environment particle adsorbed low-surface-energy cleavage planes in the elastic stress concentration zones, and anodic dissolution along the crack fronts. Besides, the corrosive environment particles primarily consist of the hydrogen atoms and the electronegative ions such as the chlorine ions.

INFLUENCE OF IRRIGATION WITH II CLASS SUITABILITY OF WATER ON THE SOIL CHEMICAL COMPOSITION

Unsatisfactory physical condition of the soil in the village Oleksandrivka (Dniprovskyi district, Dnipropetrovsk region, Ukraine) necessitated a long-term research to find out the cause of this phenomenon. The type of soil of the experimental plot is established – chernozem ordinary low-humus leached on loamy forest. There are the soil section, the results of the spectral analysis of the soil, the humus content and the physicochemical properties of the soil of the research area. The article has the highlights results of chemical analysis of irrigation water from the reservoir on the Samara River. According to the results of the analysis, irrigated water belonged to the II quality class – "Limitedly suitable" in the all years of research. To establish the effect of class II water irrigation, the chemical composition of the water extract was determined. These researches showed on the anionic composition of the increase in SO4 ions relative to the option without irrigation for all years of observation. It was due to the entry of these ions into the soil along with irrigation water. Without irrigation the amount of sulfates gradually decreased. It was 2.25 meq/100 g of soil in the fifth year. There was a clear tendency to increase chlorine ions in irrigation option. The amount of chlorine increased to 1.5 times compared to the non-irrigated option. Therefore, the chemistry of the site was chloride-sulfate and sulfate. According to the cationic composition, the largest amount was accounted for by sodium ions. The amount of Na + 1 in the irrigated option increased by 34% on average when comparing with the control option. In the absence of irrigation, the site is slowly desalinated by reducing the ratio of Na/Ca ions by an average of 8.7 units compared to irrigated options. For some years of research the soil without irrigation option was referred to the slightly saline type.

Effect of cations on the removal rate of chloride ions and mechanism analysis in high-salt wastewater

Precipitation dechlorination has the advantage of being a simple process with a low cost. However, there are few reports on the effect of cations on dechlorination. In this study, we investigated the effect of cations in high-salt wastewater on the removal of chlorine ions by cuprous chloride precipitation and analysed the corresponding mechanism. A series of investigations revealed that Fe3+ could oxidise sulphite, thereby reducing the removal rate of chlorine ions. The reaction between magnesium and sulphite results in precipitation, which has a slightly adverse effect on the removal of chloride ions. Hexavalent chromium oxidises the chloride ion, resulting in the formation of chlorine gas, which improves the removal rate. Ferrous and manganese, however, do not have a notable effect on chlorine removal.

Studying the rate of polyphenol oxidase activity in apples using a colorimeter

Salt is one of the oldest methods used to preserve food and help it stay fresh by preventing rotting due to its antibacterial properties. This study was therefore conducted to understand how the increase in salt concentration affects the rate of change of polyphenol oxidase activity in apples using a colorimeter. A colorimeter is a device used to measure absorbance of particular wavelengths of light by specific solutions, in this case, Granny Smith Apple juice. The results correlated with the hypothesis which is predicted that as the salt concentration of the dilutions increase, there will be a decrease in the rate of change of absorbance because the chlorine ions from the salt will inhibit the polyphenol oxidase activity and prevent further oxidation of phenols to quinones, limiting the polymerization and formation of melanin. The results confirm that salt is a non-competitive inhibitor of polyphenol oxidase because it slows down the catabolic processes in apples- mainly the breakdown of glucose. However, salt is a non-competitive inhibitor of PPO but as for lower concentrations, such as 0.25M and 0.50M, the higher concentration of substrates still mitigates the effect of salt as an inhibitor to a significant extent.