Additional Energy Source Research Articles

Multi-effect Distillation with Heat Pump Integrated

This article presents a study and simulation of the desalination system consisting of a heat pump HP and a multi-effect distillation MED unit. Electric energy using in HP is provided by photovoltaic panels and wind turbines ,for a possible installation of the system on an isolated sites.The proposed desalination system uses an additional source of thermal energy in order to make HP and MED integration optimal and to reduce HP Electrical energy consumption per cubic meter of distilled water (kwh/m3).The main idea is to use geothermal-solar thermal energy and heat from HP as two thermal inputs in the multi-effect distillation unit MED. Thermal rejection from MED is recovered to be used as heat input in HP that based on mechanical compression of working fluid. The HP can use the working fluids (R22, ammonia) for a number of reasons, including that the two previous fluids are very dense at the saturated vapor state compared to water. A thermodynamic analysis of the desalination system was performed at steady state, using the thermodynamic properties of the Coolprop database. The simulation results showed a minimum value of electrical energy consumption, without consideration the contribution of auxiliary thermal energy :(10.487 kwh/m3 | effect numbre:5).The simulation results showed a minimum value of volumetric flow rate of the working fluid ,before compression : (17.685 m3 of working fluid per m3 of distilled water | effect numbre:12 | contribution ratio of auxiliary thermal energy:46.6 %).

The thermal impact of stored water as supplementary energy source for a solar air heater

AbstractSolar energy system optimization is a critical consideration for expanding its reach and competitiveness against traditional energy sources. This study specifically targets solar flat plate collectors, focusing on the concept of solar air collectors with an innovative enhancement strategy. To fulfill energy requirements across various applications like heating and drying, setting up collector arrays, such as solar air and water heaters, becomes imperative for meeting desired energy outputs. This research employs numerical analysis to investigate the energy efficiency of a modified solar air heater (MSAH). The enhancement involves integrating a parallelepiped enclosure filled with water, connected to a solar flat plate water collector, into the collector's rear. This water‐filled enclosure serves as a storage tank for the solar water heater. Simulation using the Fluent CFD code is conducted based on meteorological conditions at the Renewable Energy Development Center (CDER) in Bouzaréah, Algeria. Numerical outcomes are compared with experimental findings. Results indicate the positive impact of utilizing the water storage tank as an additional energy source. This modification leads to a substantial 57% performance increase in the MSAH compared with the standard version. This elevated efficiency remains consistent even during periods of reduced solar radiation, owing to the supplementary energy contribution from the solar water heater. In contrast, the standard version's performance hinges solely on available solar radiation for energy generation. This research underscores the potential of combining solar air and water heaters to enhance solar energy systems' efficiency and dependability, facilitating their practical implementation and sustainable utilization.

Development of operation algorithm of electric drive of an electric vehicle in urban cycle

BACKGROUND: Increasing energy efficiency of an electric vehicle is one of the most relevant issues at the current state of transport development. It is known that chemical current sources used in traction electric drive of vehicles have low specific power, low efficiency and high cost that makes the electric transport development difficult.
 AIMS: Making the choice of strategy of manufacturing of electric vehicle with batteries.
 METHODS: The mathematical models of various vehicle driving cycles, such as: the UNECE Regulation 83 urban cycle, NEDC, WLTC, JC08, EPA HWEET were used in the study that made possible to confirm adequacy of the developed structural model of the electric drive.
 RESULTS: The structural layout of the traction electric drive of an electric vehicle with combined energy source has been developed; the algorithm of its operation in the urban driving cycle has been defined. Electric transport efficiency was assessed during the study. The analysis showed that vehicles with solely chemical on-board energy sources do not have any prospects due to unsatisfactory technical properties and consumer attributes. Review of capacitors was performed in order to define the possibility of using them as energy source for next-generation vehicles. The study revealed sufficient advantages of capacitors in many respects. Analysis of vehicle motion in urban cycle was performed in order to develop the optimal design. The electric drive layout with a lithium-ion traction battery as the main energy source and a capacitor as the additional energy source was chosen.
 CONCLUSIONS: This solution makes it possible to develop the electric drive with optimal mass and dimensional parameters, to increase service life of energy storage and mileage without recharging of a vehicle. In addition, the combination of two electric energy accumulators and the developed algorithm of their operation makes it possible to achieve high efficiency of energy transferring.

A Massive Hot Jupiter Orbiting a Metal-rich Early M Star Discovered in the TESS Full-frame Images

Observations and statistical studies have shown that giant planets are rare around M dwarfs compared with Sun-like stars. The formation mechanism of these extreme systems has remained under debate for decades. With the help of the TESS mission and ground-based follow-up observations, we report the discovery of TOI-4201b, the most massive and densest hot Jupiter around an M dwarf known so far with a radius of 1.22 ± 0.04 R J and a mass of 2.48 ± 0.09 M J, about 5 times heavier than most other giant planets around M dwarfs. It also has the highest planet-to-star mass ratio (q ∼ 4 × 10−3) among such systems. The host star is an early M dwarf with a mass of 0.61 ± 0.02 M ⊙ and a radius of 0.63 ± 0.02 R ⊙. It has significant supersolar iron abundance ([Fe/H] = 0.52 ± 0.08 dex). However, interior structure modeling suggests that its planet TOI-4201b is metal-poor, which challenges the classical core-accretion correlation of stellar−planet metallicity, unless the planet is inflated by additional energy sources. Building on the detection of this planet, we compare the stellar metallicity distribution of four planetary groups: hot/warm Jupiters around G/M dwarfs. We find that hot/warm Jupiters show a similar metallicity dependence around G-type stars. For M-dwarf host stars, the occurrence of hot Jupiters shows a much stronger correlation with iron abundance, while warm Jupiters display a weaker preference, indicating possible different formation histories.

Рационализация режимов поверхностной закалки ВЭН ТВЧ рабочих поверхностей пуансона в условиях гибридной обработки

Introduction. The development of a cluster of hybrid metalworking systems in the machine tool industry is associated with a number of positive consequences. First, such systems help reduce production costs by optimizing the use of resources and energy. This is especially true in the face of increased competition and a trend towards savings. Secondly, hybrid systems enable the production of quality products with increased efficiency. By integrating various functions in one process equipment, metalworking processes become more efficient and precise. This reduces the amount of defective products and improves the quality of the final ones. In addition, hybrid metalworking systems have autonomous functionality, which is especially important in flexible engineering production, where rapid changeover and adaptation to various production tasks is required. Thus, hybrid metalworking systems represent an important step in the development of modern mechanical engineering, helping to reduce costs, increase efficiency and ensure high product quality. The purpose of this work is to increase efficiency and reduce energy consumption during surface-thermal hardening of machine parts through the use of concentrated energy sources under integral processing conditions. Theory and Methods. To achieve this purpose, studies were carried out on the possible structural composition and layout of hybrid equipment integrating mechanical and surface-thermal processes. When developing the theory and methods, the main provisions of the structural synthesis and components of metalworking systems were taken into account. Theoretical research is based on the application of system analysis, geometric theory of surface formation and design of metalworking machines. The experiments were carried out on a modernized multi-purpose machining center MS 032.06, equipped with an additional energy source, which was a microwave thyristor-type generator SHF-10 with an operating frequency of 440 kHz, which implements high-energy heating by high-frequency currents. Structural studies were carried out using optical and scanning microscopy. The stress-strain state of the surface layer of the part was evaluated by mechanical and X-ray methods for determining residual stresses. The microhardness of the hardened surface layer of the parts was evaluated on a Wolpert Group 402MVD instrument. Results and discussion. An original method for conducting structural-kinematic analysis for pre-project studies of hybrid metalworking equipment is presented. Methodological recommendations were developed for the modernization of metal-cutting machine tools, allowing high-energy heating with high-frequency currents (HEH HFC) on a standard machine tool system and creating high-tech technological equipment with enhanced functionality. It has been experimentally confirmed that the introduction of the proposed hybrid machine into production in combination with recommendations for the appointment of high-frequency electric power units for integral processing of punch-type parts allows increasing the productivity of surface hardening by 36–40 times and reducing energy costs by 6 times.

Connecting multiple vehicular PEM fuel cells to electrical power grid as alternative energy sources: A Case Study

Advances in fuel cell (FC) technology make them an alternative energy source in several applications such as static, portable, and transportation. Recently, the energy needs of hydrogen electric vehicles, which have developed as an alternative to battery electric vehicles (BEVs) and have significant potential in the future, are met by vehicular hydrogen FCs. In this regard, fuel cell electric vehicles (FCEVs), which have started to take their place in the transportation sector, can also be used as an additional energy source with their energy unit for electrical power grid-connected systems. In grid-vehicle integration, vehicular FCs can meet a significant part of the electricity consumption when parked and help stabilize the grid. In this study, multiple vehicular PEM fuel cells (PEMFCs), the most widely used in FCEVs, support the residential grid by injecting electrical power into the connecting system. For this, a multi-input dc-dc boost converter interface is designed and utilized to manage electrical energy from vehicular PEMFCs to the electrical power grid instead of a conventional single-input dc-dc boost converter. In the dc-dc converter control, Incremental-Conductance (InC) maximum power point tracking (MPPT) method is utilized to extract maximum power from PEMFCs. Subsequently, the extracted electrical energy is supplied to the grid through a full-bridge inverter controlled by hysteresis pulse width modulation. The designed grid-support system supplied by vehicular PEMFCs in the ratings of 75 kW, 100 kW, and 125 kW are connected to local dynamic loads and analyzed for a 24-h operation. The minimum load consumption value is 84.6 kWh at midnight while load consumes at most 396.2 kWh during the daytime. Various connection situations of vehicular PEMFCs are considered to examine the energy flow analysis between vehicles and the grid/consumer side. A detailed economic analysis has been carried out by using hourly energy values in terms of load profile and generated energy to show the profit amount on the user side. While the cost of the energy consumed by the loads is calculated as €1004.8 without connection to the grid of FCEVs, the amount of profit obtained on the load side is measured as €943.9 with the connection.

Application of Plant Microbial Fuel Cell (Pmfc) to Agricultural Industry in Contribution to Green Energy

Most of the innovation used by humans depends on electricity, thus becoming a crucial necessity. It enables people to live harmoniously and comfortably with the help of electricity which gives life to human inventions. Without electricity, most human inventions would be useless or nonexistent. Microbial Fuel Cell was conducted to test the efficiency of the generated current of microbes living inside the wet lands. By the use of the existing MFC series circuits, the researchers found out that there is an enough current that the MFC generated through electrodes (Zinc and Copper). The present study experimentally investigated the efficiency of generated current in MFC enough to power up low electronic materials such as: LED Light bulbs and Ditrio LED Lights. The farm lands will serve as the main source of electricity where the sludges will be taken and gathered to create a series circuit composed of two different prototypes.The global need for energy is always rising. In this case, carbon-based fuels have in one way or another provided for a significant share of the total energy requirement. As a result, fossil fuel resources have been severely depleted, which is now contributing to an ecological imbalance. Additionally, the burning of fossil fuels produces a significant amount of carbon dioxide, a significant greenhouse gas that has severe effects on the climate. MFC Systems or Microbial Fuel Cells Systems is a set of technology that uses microorganism as catalysts to oxidize organic and inorganic matter and generate current. Basically, wastewater such as sludge could carry these bacteria so it would be suspended to the system to generate current. It works as a battery where stacking multiple MFCs would create a higher voltage enough to power a household (Chaturvedi, Bioresources & Bioprocessing, 2016). This allows bacteria to facilitate in electron transfer processes as the propose application of Plant Microbial Fuel Cell to Agricultural industry especially in farmlands is to assess the feasibility as potential source of electricity. The MFC system in farmlands may serve as an additional source of renewable green energy in contribution to fight against climate change.

Biochar and other carbonaceous materials used in steelmaking: Possibilities and synergies for power generation by direct carbon fuel cell

The objective of this study is the preliminary investigation of the feasibility of using a low-temperature molten hydroxide direct carbon fuel cell as an additional energy source for steel production by electric arc furnace. For this purpose, four carbonaceous materials related to the steel industry (electrographite, coke, torrefied biochar and hydrochar) were selected and characterized to predict their electrical behavior before their actual introduction as fuels. Special attention was paid to both the morphological effect (bulk/pellet or powder) and the chemical composition of the fuels on the electrical performance of the cell. Electrical measurements showed the positive influence of powder morphology, with coke powder having the highest peak power density value (49.6 mW/cm2). Electrographite was found to be useable only as a powder (18.7 mW/cm2), as the high chemical stability of the bulk morphology, provided by the smooth surface and the pitch used as a binder, acted as inhibitors of the carbon oxidation reaction. Although biochar appeared superior to hydrochar when inserted as powder (23.5 vs. 18.2 mW/cm2), the latter showed promising results also inserted as pellet. the latter also showed promising results when inserted as a pellet. Specifically, once inserted within the molten hydrochar, the binder used to produce the hydrochar is removed changing the morphology from pellet to sandy/powdery, negating the penalizing effect of the lower surface to volume of bulk morphology (15.8 vs. 18.2 mW/cm2) and offering the advantage of avoiding the milling process and related fine particulate production from an industrial point of view.

Long-Chain Alkylphenol Biodegradation Potential of Soil Ascomycota

A total of 11 ascomycete strains destructing technical nonylphenol (NP) and 4-tert-octylphenol (4-t-OP) were isolated from NP-contaminated soddy-podzolic loamy soil (Leningrad Region, Russia). The isolates proved capable of degrading NP and 4-t-OP at a high load (300 mg/L). The most efficient Fusarium solani strain 8F degraded alkylphenols (APs) both in cometabolic conditions and in the absence of additional carbon and energy sources. A decrease in APs was due to biodegradation or biotransformation by the strain and, to a minor extent, absorption by fungal cells. NP and 4-t-OP half-lives were, respectively, 3.5 and 6.4 h in cometabolic conditions and 9 and 19.7 h in the absence of additional carbon and energy sources. Amounts of the lipid peroxidation product malondialdehyde (MDA) and reduced glutathione (GSH) increased during NP and 4-t-OP biodegradation in cometabolic conditions by 1.7 and 2 times, respectively, as compared with a control. A high GSH level in F. solani 8F cells potentially implicated the metabolite in both AP biodegradation and strain resistance to oxidative stress. The study is the first to report on the NP and 4-t-OP degradation by the ascomycete F. solani in cometabolic conditions and in the absence of additional carbon and energy sources. The high AP degradation potential of soil ascomycetes was assumed to provide a basis for new environmentally safe bioremediation technologies for purification of soils and natural and waste waters contaminated with endocrine disruptors.

The combined effects of lipoic acid and sodium acetate on metabolism, redox balance, and utilization of yolk reserves of Artemia sp. nauplii

Lipoic acid (LA) has been an antioxidant with proven benefits in different species of productive interest. However, there is evidence of the effect of LA as a growth repressor and, consequently, of zootechnical performance. This study evaluated the effect of the co-administration of LA and short-chain fatty acid, sodium acetate (SA), as an additional source of energy on the utilization of yolk nutrients in Artemia sp. nauplii. A factorial experiment was designed with four levels of LA (0.0, 0.05, 0.5, and 5.0 μM) and four levels of SA (0.0, 2.0, 4.0, and 8.0 mM). Over 24 h, with sampling every 6 h, the total ammoniacal nitrogen (TAN) concentration in water, the concentration of protein, triglycerides, glucose, and the antioxidant capacity (ACAP) was evaluated in the artemia. The electron transporter system (ETS) activity and production of reactive oxygen species (ROS) in vivo were also recorded. Both LA and SA decreased TAN production. At 18 h, LA caused significant decreases in glucose content at the concentrations of 0.5 and 5.0 μM. On the other hand, SA preserved protein values in a dose-dependent manner at 12 h. Regarding ACAP, the LA showed ambivalent effects on this parameter, promoting a higher ACAP at 6 h; however, it promoted a more pro-oxidant state in the metanauplii at 24 h. While the ETS activity increased at 6 h, as an effect of the SA and LA administered separately, the co-administration of LA and SA revealed a possible antagonism that caused a decrease in the ETS activity by the action of LA. As for ROS, a decrease in production rates was found with the administration of LA, which was more noticeable at LA concentrations within the 0 and 2 mM levels of SA from 18 h onwards. Finally, the final energy content showed a scenario of the preservation of the energy reserves of artemia nauplii with the addition of SA. As expected, the LA negatively affected the energy content of the animals; however, the treatment with the highest energy content was the one that received 0.05 μM LA and 8.0 mM SA, suggesting the possibility of using these compounds together in order to compensate the side-effects of LA.

Evaluation of Voltage Stability in Microgrid-Tied Photovoltaic Systems

These days, with the significant increase in the use of renewable energy sources as additional energy sources connected to the distribution network, many challenges and difficulties arise in ensuring sustainability and reliability. The generation, transmission and distribution, in the current state of the electricity system, are facing quite dynamic changes. They are the result of the liberalization of the energy market, the increased use of renewable energy sources such as photovoltaic systems, wind turbines and the charging stations for hybrid and electric vehicles. The most important factors are related to the balancing of the energy system, the analysis of voltage stability, overcoming the consequences of the increase in short-circuit currents, increasing the transmission capacities of the system forming and distribution networks, as well as the accurate forecasting of the development of loads and consumption over the coming years. This article presents an analysis of the voltage stability in a smart microgrid for two different scenarios. The studied cases describe a linear low-voltage p-type microgrid with loads connected to it at different nodes. Data on the type and cross-section of the conductors of the studied power line are presented. Simulation studies were carried out to determine the limits of grid voltage stability when connecting photovoltaic plants with a set power. The simulation results are commented on and an analysis of the optimal operating mode of the system is realized. The model studies were implemented in the NEPLAN program environment. The research carried out allows an evaluation of the permissible limits for network stability when connecting photovoltaic plants. Through this evaluation, it can be determined how many and at which node the loads should be connected without causing an imbalance in the network. This is useful from the point of view of ensuring the sustainability and reliability of electrical energy in a microgrid.

Syngas methanation over a metal hydride catalyst: Technology performance, efficiency and economic profitability

In the last decade, biomass has been considered one of the main renewable energy sources to replace fossil fuels and consequently, biomass conversion technologies for the production of alternative fuels will play a specific role in the future energy as green biofuels for the transport sector or a power generation at small-scale distributed plants. During the thermal conversion - gasification, biomass is converted into more valuable products - syngases which could be used for biomethane production. Though, some challenges still exist related to the broad applicability of the thermal conversion of biomass to biomethane: costly short-life catalysts and a low conversion efficiency due to the high amount of carbon monoxide/dioxide in syngas.To overcome these challenges, an innovative biomethane production concept based on the plasma-assisted gasification and conversion of synthetic gases to biomethane was developed and tested, including research on the adaptability of two catalysts, magnesium nickel and magnesium nickel hydride, for raw syngas conversion. The performance of catalysts was investigated in a fixed bed type reactor using raw syngas obtained from plasma-assisted gasification.The results indicate the magnesium nickel hydride catalysts' good activity and functionality for converting carbon dioxide and carbon monoxide-containing syngas. A high conversion of 0.997 is reached. Determined that the surplus of hydrogen promotes the conversion of carbon oxides, though the volumetric concentration of methane (the maximum of 86.4 vol%) in product gas is reduced. Considering that the developed technology concept can be integrated into small combined heat and power plants, bio-waste generating plants, or decentralized areas as an additional source of renewable energy or biofuel production, the energy-mass balance and economic analysis for the optimization of 1 MWh bio-CH4 production concept was provided.

Analytical investigation of the dew point water recovery system with potential application for drinking water production

The article presents the analytical investigation of the Dew Point Water Recovery (DPWR) system with potential application for drinking water production. Four different configurations of the DPWR system were proposed, differing in the number and type of dew point cooling exchangers used, and their operation was described using a validated convective heat transfer coefficient mathematical model. It was found that the three stage configuration of the DPWR system with a regenerative exchanger has the best water recovery performance, while the three stage configuration with a counter-flow exchanger has the best ratio of energy supplied to the system in relation to the amount of water produced. It was also found that the DPWR system can operate in a wide range of operating conditions with a specific electric energy consumption reaching below 0.9 kWh/m3 and GOR in the range of 0.36–2.16. What distinguishes the DPWR system from other methods of drinking water production is the ability to work without an additional source of thermal energy apart from the energy of the air supplied to the system. Thanks to this property, the system has the potential to fill the technological gap of a low-energy and easily accessible method of drinking water production.

Гибридное технологическое оборудование: к вопросу рационального выбора объектов модернизации при проведении работ, связанных с дооснащением стандартной станочной системы дополнительным концентрированным источником энергии

Introduction. Improving the competitiveness of manufactured products is impossible without achieving high rates of resource and energy saving, while providing modern machine tools with the proper level of production flexibility in combination with guaranteed high values of processing productivity and the required level of parts manufacturing quality. Insufficient or excess capacity of technological equipment leads to a decrease in its economic efficiency, an increase in capital costs and, as a result, an increase in the cost of production. In the machine tool industry, which is a strategically significant and basic industry for the modernization of mechanical engineering, there is a special interest in the development of a new type of technological equipment that makes it possible to implement methods for modifying the surface layers of parts by processing it with concentrated energy sources. The combination of two processing technologies (mechanical and surface-thermal operations) in the conditions of integrated equipment makes it possible to level the shortcomings of monotechnologies and obtain new effects that are unattainable when using technologies separately. Ensuring an optimal level of quality — one of the unconditional requirements of a market economy — is a priority when developing the overall concept of technological equipment. Thus, it should be noted that the required and specific set of consumer properties are laid down during the design. And, therefore, the problem of quality optimization belongs to the field of forecasting and should be comprehensively addressed at the initial stage of developing the concept of technological equipment. The purpose of this research is to rationally choose the objects of modernization when carrying out work related to retrofitting a standard machine tool system with an additional concentrated energy source. Methods: Theoretical studies of the possible structural composition and layout of hybrid equipment during the integration of mechanical and surface-thermal processes were carried out taking into account the main provisions of structural synthesis and components of metal-cutting systems. During the research, issues related to the main provisions of system analysis, the geometric theory of surface formation, the design of metal-cutting equipment, methods of mathematical and computer modeling were raised. Results and discussion. Theoretical studies is found that currently, most of the parameter-oriented (dimension) series of general-purpose metal-cutting machines, built according to the law of geometric progression with a constant denominator, are the cause of multiple duplication of individual size ranges on machines of the same series. This gives grounds to talk about an unreasonable increase in the number of its members and, as a result, to an increase in the cost of designing, manufacturing and operating equipment. The authors adhere to the point of view that in order to ensure maximum efficiency of hybrid metal-cutting equipment, it is necessary to implement a parameter-oriented series built with a variable denominator. Such a principle of forming a parameter-oriented series makes it possible to provide an almost equal probability of processing a surface of any size with maximum productivity with a threefold overlap of ranges. Approbation of the technique for forming the structure of parametric series is carried out. It is theoretically proven that during the operation of vertical milling machines of the operating parameter-oriented series with the denominator φ = 1.26 (GOST 9726-89), there is a multiple overlap of individual size ranges, reaching a ninefold value in a certain range of sizes, which, of course, affects the efficiency of the existing machine tool holding. In turn, when synthesizing a promising parametric series of vertical milling machines with a cross table, it was shown that the new parameter-oriented series has a smaller number of members. Reducing the range of manufactured and modernized machine tools will increase the serial production and reduce current expenses on repairs and maintenance. Moreover, this effect is achieved while maintaining the flexibility of the machine tool holding.

Study of a Regional Turboprop Aircraft with Electrically Assisted Turboshaft

Hybrid-Electric Propulsion (HEP) could be part of the solution to decrease emissions associated with regional commercial aviation. This study presents results for the aircraft level fuel reduction potential of a regional turboprop concept with an HEP architecture and Entry-Into-Service (EIS) in 2035+. The configuration specifically tackles the elaborated challenges of introducing an additional electrical energy source to the configuration by employing a twofold electrical assistance to a turboshaft engine in combination with an innovative thermal management concept. Relevant components and disciplines were modeled and incorporated into an integrated aircraft design environment. The behavior and interaction of the HEP architecture with the aircraft was thoroughly investigated. A best-performing configuration was derived and compared with a conventional reference configuration following a State-of-the-Art (SoA) reference aircraft approach. For a typical mission with 200 nmi range, a block fuel reduction of 9.6% was found. However, the assumed battery performance characteristics limited the reduction potential and led to a fuel burn increase for the 600 nmi design mission. Furthermore, sourcing the non-propulsive subsystems directly from the on-board battery was detrimental. The innovative Thermal Management System (TMS) located in the propeller slipstream showed a synergistic effect with the investigated configuration.

The Effects of the Polar Rain on the Polar Wind Ion Outflow From the Nightside Ionosphere

AbstractThe polar wind, consisting of low‐energy ions and electrons, is an outflow along the open magnetic field lines from the polar cap ionosphere to the magnetosphere. Previous studies found that both solar radiation and solar wind electromagnetic energy are the two main energy sources for the polar wind. The polar rain, being field‐aligned precipitating electrons from the solar wind to the polar cap, may provide additional energies for the polar wind. This scenario is complicated as simulation studies show that polar rain changes the electric potential structures over the polar cap ionosphere. It is unclear how the polar rain affects the polar wind ion outflow. In this study, we show a positive correlation between the polar wind and the polar rain. Meanwhile, the polar wind is generally diminished in regions with strong Earth's magnetic field, suggesting the |B| modulates the penetration depth of the polar rain through the magnetic mirror force and thus the energy dissipation of the polar rain. Therefore, the polar rain can be an additional energy source for the polar wind although the polar rain has generally smaller energies and intensities than the particle precipitations in the auroral regions.

Application of Autoregressive Distributed Lag Model to Assess the Environmental Sustainability in Bangladesh

This research inspects the associations among several macroeconomic factors in Bangladesh using yearly time series data from 1971 to 2019. It also aimed to determine if the environmental Kuznets curve (EKC) hypothesis exists in Bangladesh or not. The findings from the stationarity tests reveal that all variables are ordered I (1) integrated. The ARDL model has been used to explore the longrun and short-run connections between variables in the model. In the long term, the projected findings established the existence of the Kuznets curve hypothesis in the GDP-energy nexus. According to the study, there is a U-shaped association between economic expansion and greenhouse gas emissions. Food production and energy consumption increase emissions, however using biomass does not assist the country to attain sustainability, as an increase in biomass increases greenhouse gas emissions by 1.12%. As a result, our government should explore additional renewable energy sources to restrict emissions and take the required actions in all areas to achieve environmental sustainability. Dhaka Univ. J. Sci. 71(1): 60-68, 2023 (Jan)

Retracted: Self-consistent models of Earth’s mantle and core from long-period seismic and tidal constraints

SUMMARYIn this study, we inverted a large set of normal-mode centre-frequencies and quality (attenuation) factors, including astronomic-geodetic data (mass, moment of inertia and tidal response), using self-consistently built models of the radial elastic and anelastic seismic structure of the Earth. The mantle models are constructed using petrologic phase equilibria in combination with a laboratory-based viscoelastic model that connects dissipation from seismic to tidal periods, whereas seismic properties for a well-mixed and homogeneous core are computed using equations-of-state. Relative to the preliminary seismic reference model (PREM), we find that for the models to fit the observations, mantle P- and S-wave velocities have to be slightly faster and slower, respectively, while outer-core P-wave velocity is slower on account of a different velocity gradient, whereas inner-core velocity structure is similar, within the uncertainties of the inferred model parameters. In terms of density, we find that the lower mantle is less dense and the outer core more dense than PREM, while the inner core is similar to PREM. To study the impact of the inferred mantle seismic velocity structure, we computed P- and S-wave traveltimes and compared these to the observations of globally-averaged P- and S-wave traveltimes from the reprocessed ISC catalogue that resulted in an excellent match. In an attempt to further refine the seismic P-wave velocity structure of the outer core, we also considered multiple core–mantle-boundary underside-reflected body wave traveltime data. Although the match to the underside reflections clearly improves as a result of a steeper velocity gradient in the outer core relative to the normal-modes- and astronomic-geodetic-data-only case, subtle differences nevertheless persist that appear to support a change in velocity gradient in the outermost core, evocative of a stably-stratified layer. The laboratory-based viscoelastic model considered here resolves the anelastic response of Earth’s mantle from long-period seismic (∼100 s) to tidal (18.6 yr) periods, accounting for both normal-mode and tidal dissipation measurements. Finally, as a potential means of refining core composition, we considered the density contrast across the inner-core boundary (ICB) based on our inverted models. The most probable ICB density difference found here is 0.3–0.45 g cm−3, which is in the lower range of earlier body-wave- and normal-mode-based predictions. This suggests that the compositional heterogeneity associated with light-element partitioning, which is considered the principal driving mechanism for the compositional convection that powers the geodynamo, may be less effective than previously thought, calling for exsolution of solids from the liquid outer core as a possible additional source of energy. This would also help address the problem of a young inner core.

Alternative Sources of Energy in Transport: A Review

Alternative sour2ces of energy are on the rise primarily because of environmental concerns, in addition to the depletion of fossil fuel reserves. Currently, there are many alternatives, approaches, and attempts to introduce alternative energy sources in the field of transport. This article centers around the need to explore additional energy sources beyond the current ones in use. It delves into individual energy sources that can be utilized for transportation, including their properties, production methods, and the advantages and disadvantages associated with their use across different types of drives. The article not only examines the situation in the Czech Republic but also in other nations. In addition to addressing future mobility, the thesis also considers how the utilization of new energy sources may impact the environment.

Mergers of neutron stars and black holes with cores of giant stars: a population synthesis study

ABSTRACT We perform population synthesis of massive binaries to study the mergers of neutron stars (NSs) and black holes (BHs) with the cores of their giant secondaries during common envelope evolution (CEE). We use different values of the efficiency parameter αCE in the framework of the energy formalism for traditional CEE (αCE ≤ 1) and including additional energy sources to unbind the envelope (αCE > 1). We constrain the possible values of αCE by comparing the results of our simulations with local rate densities of binary compact object mergers as inferred from gravitational-wave observations. We find two main evolutionary pathways of binary systems that result in NS–core mergers, while only one of them can also lead to the merger of a BH with the core of the giant star. We explore the zero-age main-sequence statistical properties of systems that result in NS/BH–core mergers and find that the two evolutionary channels correspond to a bimodal distribution of orbital separations. We estimate the percentage of the mergers’ event rates relative to core-collapse supernovae. We include the effect of mass accreted by the NS/BH during CEE in a separate set of simulations and find that it does not affect the mergers’ event rates.