Reliability of AC thick-film electroluminescent lamps

The reliability of AC thick-film EL devices has been studied. The AC thickfilm EL devices were fabricated by Novatech Inc. using the industrial print screen technology. The analysis of reasons for failure has been proposed. The dependence of EL lamp parameters on physical properties of the device EL layers was found. Our analysis of the breakdown spot showed that improvement of reliability can be reached using the additional dielectric layer between the phosphor layer and transparent electrode, high concentration of phosphor powder 70 % and binder 30 %, balanced resistance between the electric circuit and EL lamp. The thickness of the phosphor layer was equal to H = (1 + √3/2)D (hexagonal packing), where D is the mean diameter of phosphor particles. The reliability dependence of EL lamp on a water adsorption property of packaging material was revealed

Three-dimensional localized coherent structures of surface turbulence. III Experiment and model validation

The paper continues a series of publications devoted to the 3D nonlinear localized coherent structures on the surface of vertically falling liquid films. The work is primarily focussed on experimental investigations. We study: (i) instabilities and transitions leading to 3D coherent structures; (ii) characteristics of these structures. Some nonstationary effects are also studied numerically. Our experimental results, as well as the results of other investigators, are in a good agreement with our theoretical and numerical predictions.Comment: 42 pages, 15 figure

Comparative Evaluation of Pyrolysis and Hydrothermal Liquefaction for Obtaining Biofuel from a Sustainable Consortium of Microalgae Arthrospira platensis with Heterotrophic Bacteria

This article presents a comparative evaluation of pyrolysis and hydrothermal liquefaction (HTL) for obtaining biofuel from microalgal biomass (MAB). The research was carried out using biomass of a stable microalgae-bacteria consortium based on Arthrospira platensis. A. platensis was chosen because of its simple cultivation and harvesting. Pyrolysis was carried out at temperatures of 300, 400, 500, and 600 °C with a constant rate of temperature change of 10 °C/min; HTL was carried out at temperatures of 270, 300, and 330 °C. The bio-oil yield obtained by HTL (38.8–45.7%) was significantly higher than that of pyrolysis (up to 21.9%). At the same time, the bio-coal yields using both technologies were almost the same—about 27%. Biochar (bio-coal) can be considered as an alternative strategy for CO2 absorption and subsequent storage since it is 90% geologically stabilized carbon

Methane pyrolysis on sponge iron powder for sustainable hydrogen production

Methane pyrolysis is one of the possible methods to produce low-carbon hydrogen. One of the most promising catalysts for methane pyrolysis is Fe due to its availability, relatively low cost and high working temperature. In the presented paper, the methane pyrolysis on unsupported (without a carrier) sponge iron in the form of powder was studied in the temperature range of 700–1100 ◦ C. Methane pyrolysis was carried out in a stainless-steel tube reactor with an inner diameter of 10 mm. The reactor was heated locally by propane burner, the length of the heated zone was about 8 cm along the reactor tube. Methane feed rates were about 50, 100, and 200 ml/min, and the residence time of methane in the 8 cm long reaction zone was about 4, 2 and 1 s, respectively. The hydrogen yield increased with an increase in the temperature and a decrease in methane feed rate. At 700–800 ◦C, the hydrogen yield did not exceed 20%. At 900 ◦C, the yield reached 28.6% at a residence time of about 4 s. At 1000 ◦C, hydrogen yield was about 40 and 66.5% at a residence time of about 1 and 4 s, respectively. At 1100 ◦C, hydrogen yield varied in the range of 70–85%. The use of a catalyst increased the hydrogen yield by 81% compared to the experiment without a catalyst at 1100 ◦C. The catalytic effect of sponge iron powder can be used in the development of methane pyrolysis plants

Recent advances and viability in sustainable thermochemical conversion of sludge to bio-fuel production

Thermochemical methods are regarded as promising approach for managing sludge, that can achieve resources and energy recovery, volume reduction followed by efficient elimination of microorganisms. This review highlights an extensive description of the implementation of thermochemical technologies involving pyrolysis, gasification and hydrothermal liquefaction for valorisation of sludge into bio-fuel thus reducing the issues related to surplus generation and accumulation of sludge in environment affecting human health followed by rapid depletion of energy resources. The paper addresses working mechanism of thermochemical processes, their implementation for sludge conversion to bio-fuel and common factors affecting the process efficiency. Various studies have proved possible potential of thermochemical techniques for conversion of sludge to bio-fuel obtaining a high yield of bio-fuel and syngas. However, few technical challenges are still there that requires further studies and understanding for a better commercialization on industrial-scale and subsequently the future perspectives have also been analysed. Data collected from existing studies revealed that hydrothermal liquefaction has the efficiency to be proved better than other thermochemical technologies for proper valorisation of sludge resulting in high bio-fuel yield

Ritual Deposit of the Sarmatian Age from the Barrow on the Lower Don Basin

Introduction. In 2007 the archaeological expedition of the State Autonomic Cultural Facility of Rostov Region “The Don Heritage” excavated burial ground Krasny IV in Aksay district of Rostov Region. In the mound of barrow No. 13 a bronze rod-shaped frontlet plate with a hook, a bronze lunula-shaped harness pendant, six bronze bridle roundels, a bone cheek-piece, and iron fragments of the, most likely, bits have been discovered. Methods and materials. In the study the standard methods of archaeological analysis are used: comparative-typological, the method of analogies, chronological, and cartographic ones. The materials are the discovered artifacts. Analysis. According to the conditions of location and composition, the assemblage from barrow No. 13 can be identified as a ritual deposit. Such assemblages are known in special literature as “hoards”, “strange assemblages” or “votive hoards”. They have been found in mounds of barrows or in natural hills without traces of human burials. Usually they consist of cauldrons or situlae (often the rest items are put into them), bridle sets with peculiar frontlet plate with a hook, silver and bronze phalerae, helmets of Western types, weapons (most often spear- and arrowheads), expensive and socially prestigious items (silver and glassware, jewelry). The presence of all these items in the ritual deposit is not necessary. These sites are concentrated in geographically opposite regions: the basins of the Southern Bug, Dniester and Prut and in the east of European Sarmatia – in the AzovDonbass, Don and Kuban basins, the Lower Volga basin and North Caucasus. Results. Close parallels to the frontlet plate, bronze lunula-shaped pendant, and bridle roundels were found in the South Bug basin (Marievka), the Dniester and Prut interfluve (Brãviceni), Romania (Zimnicea), the North Caucasus (Prochnookopskaya, Geymanovsky, Giaginskaya), the Don and Volga interfluve (Kachalinskaya). All of these sites are identified as ritual deposits of the late 2nd – 1st centuries BC. The assemblage from barrow No. 13 should be dated to the same time. The ritual deposits of Eastern Europe could be divided into two chronologically different groups. The sites of the early group (3rd – early 2nd century BC) have appeared in the North Caucasus and concentrated in the North-Western Pontic region. It is assumed that they belong to the Хsaiai, Saudaratai and Thissamatai mentioned in the Olbian decree in honor of Protogenes. The sites of the late group (the late 2nd – 1st centuries BC) in the Northern Pontic Region, the Don basin, the North Caucasus and adjacent territories belong, most likely, to the Sarmatians

3D Bioprinting to Fabricate Living Microalgal Materials

3D bioprinting to fabricate live microalgal materials is an impending technological transformation in the field of microalgal biotechnology. Balasubramanian et al. have demonstrated 3D bioprinting using alginate hydrogel encapsulation to create unique photosynthetically active microalgal biomaterials that are biodegradable, regenerative, and eco-friendly. © 2021 Elsevier Lt

Impact of pyrene (polycyclic aromatic hydrocarbons) pollutant on metabolites and lipid induction in microalgae Chlorella sorokiniana (UUIND6) to produce renewable biodiesel

Pyrene (polycyclic aromatic hydrocarbon), an anthropogenic organic pollutant prevalent in various ecological units, receives more attention for bioremediation and energy transformation using microalgae. In this study, we have used pyrene pollutant (50–500 ppm) to evaluate the half-maximal inhibitory concentrations (IC50) of Chlorella sorokiniana and the impact on metabolites as well as the induction of lipid biosynthesis to produce renewable biodiesel. Pyrene concentration at 230 ppm (IC50) caused half-maximum inhibition for the 96 h incubation. The harvest in the stationary stage (day 16) for C. sorokiniana revealed a biomass generation of 449 ± 7 mg L−1 and 444 ± 8 mg L−1 dcw in the control medium and pyrene IC50 medium, respectively. An insignificant decline in biomass generation (1.2%) was observed due to the stress effect of the pyrene IC50 medium on metabolic biosynthesis. Although contrary to biomass generation, IC50 of pyrene assisted to induce lipid biosynthesis in C. sorokiniana. The improvement in lipid biosynthesis was observed as ~24% higher in pyrene IC50 compared to the control medium. The chemical composition of the microalgae biomass, metabolites, and lipids was examined using FTIR spectra. The extracted lipid was transesterified to produce biodiesel via methanolic-H2SO4 catalysis. The renewable biodiesel obtained was evaluated using FTIR and 1H NMR spectra. The transformation efficiency of the lipid of C. sorokiniana in biodiesel was calculated as ~81%. This research offers the incentive in lipid biosynthesis in microalgae cells using pyrene for the production of renewable and sustainable ecological biofuels along with bioremediation of pyrene. © 202

Effect of Thermal Treatment of Aluminum Core-Shell Particles on Their Oxidation Kinetics in Water for Hydrogen Production

The effect of thermal treatment of aluminum core-shell particles on their oxidation kinetics in water for hydrogen production was investigated. The samples were obtained by dividing dried aluminum powder, partially oxidized by distilled water, into eight portions, which were thermally treated at temperatures of 120, 200, 300, 400, 450, 500, 550 and 600 °C. Alumina shell cracking at 500–600 °C enhances hydrogen generation due to uncovering of the aluminum cores, while sharp thickening of the protective oxide film on the uncovered aluminum surfaces at 550–600 °C significantly reduces reactivity of the core-shell particles. For these reasons, after reaction with distilled water at 90 °C for two hours, the highest hydrogen yield (11.59 ± 1.20)% was obtained for the sample thermally treated at 500 °C , while the yield for aluminum core-shell powder without heat treatment was only (5.46 ± 0.13)%. Another set of experiments employed multiple consecutive cycles of alternating oxidation by water and thermal treatment at 500 °C of the same powder sample. As predicted, the hydrogen yield gradually decreased with each subsequent experiment. The series of six cycles resulted in a total hydrogen yield of 53.46%