Search Results (12,944)

This paper presents the energy, exergy, and economic analysis of a new cogeneration cycle for the simultaneous production of power and cooling operating with an ammonia–water mixture. The proposed system consists of an absorption cooling system integrating a reheater, a separation tank, a compressor, a turbine, and an expansion valve. In addition, internal rectification is applied, improving the system’s performance. Mass, energy, and exergy balances were applied to each system’s component to evaluate its performance. Additionally, the costs of each component were determined based on economic equations, which take into account mass, heat flows, and temperature differences. A parametric analysis found that the system reached an energy utilization factor of 0.58 and an exergy efficiency of 0.26 using internal rectification at T_G = 120 °C, T_A = 30 °C, and T_E = 10 °C. The power produced by the turbine was 26.28 kW, and the cooling load was 366.8 kW. The output costs were estimated at 0.071 $/kW. The condenser was found to be the most expensive component of the system, contributing 28% of the total cost. On the other hand, it was observed that the generator was the component with the highest exergy destruction, with 38.16 kW. Full article

The safety of people’s everyday water consumption has been gravely challenged by wastewater from printing and dyeing, however, research on effective contaminants removal from wastewater is encouraging. In this experiment, attapulgite modified with Mg²⁺ was calcined, and chitosan was added to create attapulgite composites. By refining the experimental parameters of the preparation, the adsorption performance of rhodamine B in wastewater was enhanced. A fully automated specific surface area and porosity investigation, a method known as X-ray diffraction, and nitrogen adsorption desorption equilibrium temperatures at 77 K were all performed. The original and composite attapulgite samples were evaluated using BET, Fourier transform infrared spectroscopy, and scanning electron microscopy. Composite materials were prepared using n (Mg²⁺)/m (AP) = 30 mmol/g, m (CS)/m (AP) = 1/3, a calcination temperature of 300 °C, and 1 h. After a series of adsorption experiments, manifesting that adding 0.2 g of attapulgite, at an initial concentration of 800 mg/L, pH of 4, temperature of 25 °C, and stirring for half an hour resulted in a maximum adsorption capacity of 325.73 mg/g. According to thermodynamic and kinetic equations, the pseudo-second-order kinetic theory is more consistent with the Langmuir adsorption isotherm (R² = 0.999). Upon examining the thermodynamic properties of ΔS, ΔH, and ΔG, it was found that the reaction is a spontaneous endothermic process that could potentially be utilized to eliminate Rh B. Full article

Waste incineration with energy recovery is a matured Waste-to-Energy (WtE) technology which has contributed immensely to the disposal and management of Municipal Solid Waste (MSW) in industrialised nations. The adoption of this technology in developing countries is currently gaining momentum due to the numerous benefits that can be derived from its use. In this study, a techno-economic assessment of MSW incineration in proposed waste incineration facilities for use in Ghana was carried out. The technical assessment was conducted by determining the plant capacity and annual electricity production based on the combustible residues of MSW collected from various population sizes in the country, while the economic assessment was carried out by determining two key economic indicators, Net Present Value (NPV) and Levelised Cost of Energy (LCOE). It was found that a total of about 400 MW of electricity can be generated from the total of about 14,000 tonnes of MSW generated in the country daily. The NPV for a 35.81 MW installed capacity of waste incineration facility was found to be USD 166,410,969.24. However, the LCOE for the 35.81 MW capacity and all others considered was greater than the tariff of electricity for their respective capacities, which means waste incineration facilities are not economically viable ventures in Ghana. The implementation of these facilities in the country would, therefore, need governmental support in the form of subsidies and tax rebates. Three locations were proposed for the piloting of waste incineration facilities in the country, and these locations are in the Accra Metropolitan, Asokore-Mampong Metropolitan, and Sekondi-Takoradi Metropolitan Assemblies. Full article

While there are software tools available for helping to conduct life cycle assessment (LCA), such as OpenLCA, these tools lack integration with process design, simulation, and optimization software. As LCA has a critical role in sustainable product design, this paper presents a platform called EMSO_OLCA, which integrates the LCA provided by OpenLCA into the Environment for Modeling, Simulation, and Optimization (EMSO). EMSO_OLCA incorporates a database of environmental impact assessment methodologies from OpenLCA and aligns with the principles of LCA outlined in ISO 14040 and ISO 14044. Validation tests were conducted to compare the results obtained by the LCA of sugarcane ethanol using OpenLCA and EMSO_OLCA, revealing a high level of agreement. The average relative error was 0.045%, indicating a negligible discrepancy between the tools. Moreover, it took only 0.3 s for the calculation, which is desirable for use with process system engineering tools. A second case study was applied to combined steam and electricity production from the combustion of sugarcane bagasse and straw in a combined heat and power system. The results show the integration of LCA with simulation and sensitivity analysis tools, thus supporting sustainable decision-making processes. EMSO_OLCA bridges the gap between LCA and process engineering, enabling a holistic approach to the sustainability, design, and implementation of environmentally friendly solutions. Full article

Flexographic printing is widely used in the packaging field, but there are still some problems in the printing of flexographic ink on non-absorbent substrates, such as low precision and unstable quality. In this paper, the printing process of flexographic ink is simulated. The interaction of fluid flow, temperature change, and solid deformation in flexographic printing is studied systematically by using the method of fluid–solid thermal coupling for the first time. The process of ink channel formation under static extrusion and fluid–solid thermal coupling was analyzed. The influences of printing pressure, printing speed, ink layer thickness, and ink viscosity on the ink channel were explored. The results show that the printing speed increases and the temperature in the stamping area increases. The printing speed is nonlinear related to the ink flow channel, the influence on the channel is slow at a low speed, the channel increases sharply at a medium and high speed, and tends to be stable at a high speed. When the printing speed is 200 m/min, the ink temperature in the stamping area is 1.5 °C higher than that at the entrance. With an increase in printing pressure, the ink flow channel width showed a trend of decreasing first and then stabilizing, and the pressure was about 0.4 MPa, showing a small fluctuation; the greater the pressure, the higher the temperature of the ink, which will change the performance of the ink and plate, causing adverse effects on the printing belt. The channel width showed obvious nonlinear characteristics with an increase and decrease in ink thickness. When the ink thickness is 30 μm, the deformation of the plate reaches the maximum, and the width of the ink circulation channel is correspondingly the widest. The change in ink viscosity has little influence on the stability of the ink’s internal flow rate and temperature field. The research results provide theoretical support for the transfer of ink printing from gravure to flexo printing. Full article

The sliding wear of Ti-6Al-4V alloys coexisting with dental amalgam in a simulated temperature-controlled cell was evaluated. Disc-shaped samples of Ti-6Al-4V (n = 30) and spherical silver amalgam (n = 30) were prepared. Discs were subjected to wear while immersed in artificial and fluoridated saliva as follows: Ti-6Al-4V–Ti-6Al-4V (G1); amalgam–amalgam (G2), and Ti-6Al-4V–amalgam (G3). Samples were analyzed for mass variation, volume loss, and surface roughness. Wear tracks were characterized by scanning electron microscopy. Wearing induced significant mass loss for all groups except G3 in fluoridated saliva: Ti-6Al-4V (p = 0.045) and amalgam (p = 0.732). These samples presented an increase in mean surface roughness (p = 0.032 and 0.010, respectively). Overall, Ti-6Al-4V showed 0.07 mm³ (95% CI: [0.06–0.07]) higher wear track volume. Ti-6Al-4V has a higher mass loss when subjected to fluoridated media but no significant roughness variation. Fluor-containing substances should be avoided over Ti-6Al-4V alloys placed in areas of mechanical wear, especially if dental amalgam is also present. Full article

Bacterial cellulose (BC) can be chemically modified and combined with other materials to create composites with enhanced properties. In the medical field, biomaterials offer advantages, such as biocompatibility and sustainability, enabling improved therapeutic strategies and patient outcomes. Incorporating lidocaine into wound dressings offers significant potential benefits. In this study, transparent BC films were produced in situ with an undefined minimal culture medium with a yeast and bacteria co-culture system on black tea (Camellia sinensis) and white sugar medium for three days. Lidocaine was incorporated ex situ into the BC matrix, and the composite film was sterilized using gamma radiation. Drug-release studies showed a two-stage release profile, with an initial fast release (24.6%) followed by a slower secondary release (27.2% cumulative release). The results confirmed the incorporation of lidocaine into the BC, producing highly transparent films with excellent thermal stability, essential for the storage and transportation of wound dressings. This study highlighted BC properties and drug incorporation and release behavior. The findings contribute towards optimizing wound dressings with controlled drug release, showcasing the potential of transparent BC films as an effective platform for wound care and drug-delivery applications. Full article

Traditional oil seals are insufficient for the high-speed and bi-directional rotation of new energy electric vehicles. Therefore, we developed a Python program focusing on micro-groove pump seals and examined the unexplored non-contact oil–air biphasic internal end-face seals. Real gas effects were described using the virial and Lucas equations. We introduced an oil–air ratio to determine the equivalent density and viscosity of the two-phase fluid in the seal. Furthermore, we solved the compressible steady-state Reynolds equation using the finite difference method. Analysing the seal’s pumping mechanisms and the effects of operating parameters on sealing performance, we assessed 17 types of hydrodynamic grooves. The results demonstrate that inverse fir tree-like grooves perform well under typical sealing conditions. Under the conditions given in this study, the pumping rate of the optimal groove type compared to other groove types even reached 633.54%. In the oil–air biphasic state, the micro-groove pump seal exerts significant dynamic pressure on the sealing surface. Seal opening force increases with rotational velocity, oil–air ratio, and inlet pressure but decreases with temperature. The pumping rate first increases and then decreases with rotational velocity, increases with oil–air ratio and temperature, and then decreases with inlet pressure. Some special working points require consideration in sealing design. Our results provide insights into designing micro-grooved pumping seals for new energy electric vehicles. Full article

Composite coatings have been successfully fabricated at the laboratory scale in many research centers around the world; however, it is still a major challenge to transfer the positive results of the work to the industrial scale. This paper presents the technology for the production of Ni-B and Ni-B/B composite coatings on a pilot experimental semi-technical line by chemical reduction. A process scheme for the fabrication of Ni-B layers and composite coatings with a nickel–boron matrix and a dispersive phase in the form of boron nanoparticles was developed. All stages of the fabrication process were described in detail. The dispersion phase of the boron particles was characterized, and the performance properties of the Ni-B and Ni-B/B composite coatings produced on a pilot electroplating line were studied. The structure and morphology of the Ni-B/B composite coatings were characterized for comparison with nickel–boron coatings. Their mechanical and tribological properties and adhesion to the substrate were studied. The influence of the dispersion phase of boron particles on the structure and functional properties of the composite coatings was evaluated. In order to improve the performance of the fabricated coatings, a heating process at 400 °C was carried out, and the performance of Ni-B and composite Ni-B/B coatings was studied after the heat treatment operation. Full article

Offshore wind energy entering the grid in coastal areas creates issues with the safe and stable operation of power systems. To control the carbon emission of power systems and increase the proportion of offshore wind consumption, a microgrid optimization model considering offshore wind power and carbon trading is proposed in this paper. To avoid the defect of Particle Swarm Optimization (PSO) falling into the local optimum prematurely, the PSO algorithm is improved by dynamically decreasing inertia weights and chaos factors. Combined with the powerful optimization capability of the genetic algorithm (GA), the improved PSO-GA algorithm is used to solve the model. The simulation results show that the improved algorithm iterates 11 times before the parameters reach the optimal value, with high convergence accuracy. The proposed approach can increase the proportion of offshore wind consumption and ensure the optimal economic performance of the system while reducing the carbon emission. Full article

This research examined the potential for utilizing waste materials generated during the production of dishes/meals and organic waste. Specifically, it evaluated the use of orange peel (OP), spent coffee grounds (SCG), and waste cooking oil in the production of soaps. For the purposes of this study, homemade soaps were made from used food oils using the cold saponification method using sodium hydroxide. During the soap preparation, spent coffee grounds and orange peel were added to the samples in increasing concentrations of 1%, 2.5%, and 5%. The quality of the individual types of homemade soaps was evaluated on the basis of physicochemical properties such as pH, moisture, total alkalinity, total fatty matter, malondialdehyde content, fat content, foaminess, and hardness. All soaps produced using the cooking oil met the ISO quality criteria and reveal a high TFM content, low moisture content, and also very good foam stability and satisfactory foaming stability. However, no relationship was observed between the use of OP and SCG in soap production and these parameters. However, according to the ABTS test, OP and SCG significantly contributed to the antioxidant properties of the soaps, while SCG-impregnated soaps performed slightly better in this respect. Soaps with SCG also had the highest levels of flavonoids. On the other hand, the fillers used for the soap formulation reduced their hardness. All soaps showed 100% solubility in water, thus confirming the biodegradability of the product. This study demonstrated the novel potential of incorporating waste products like orange peel, spent coffee grounds, and waste cooking oil into homemade soaps, highlighting their contributions to its antioxidant properties and water solubility while ensuring high quality standards. Full article

Power-to-gas technology provides an emerging pathway for promoting green and low-carbon transformation of energy systems. Through the processes of electrolyzing water and the methanation reaction, it converts surplus renewable energy into hydrogen and natural gas, offering an effective approach for large-scale integration of renewable energy sources. However, the optimization of existing integrated energy systems has yet to finely model the operational characteristics of power-to-gas technology, severely limiting the energy conversion efficiency of systems. To address this issue, this paper proposes an integrated energy system operation strategy considering the slow dynamic response characteristics of power-to-gas. Firstly, based on the technical features of power-to-gas, an operational model for electrolyzing water to produce hydrogen is constructed, considering the transition relationships among cold start-up, hot start-up, and production states of a methanation reaction, thereby building a power-to-gas operation model considering slow dynamic response characteristics. This model finely reflects the impact of power-to-gas operational states on methanation, facilitating accurate representation of the operational states of methanation. Then, considering the energy conversion constraints and power balance of various coupled devices within integrated energy systems, an optimization model for the operation of the integrated energy system is constructed with the total daily operation cost of the system as the optimization objective. Finally, simulation comparisons are conducted to demonstrate the necessity of considering the slow dynamic response characteristics of power-to-gas technology for integrated energy system operation. The case study results indicate that the proposed power-to-gas operation model can accurately simulate the methanation process, facilitating the rational conversion of surplus renewable energy into natural gas energy and avoiding misjudgments in system operation costs and energy utilization efficiency. Full article

The lake littoral zone is periodically exposed to water due to water level fluctuations, driving the succession and distribution of littoral vegetation covers, which complexly affect nutrient biogeochemical transformation. However, the combined effects of water level fluctuations and other environmental factors on microbial characteristics and functions at the regional scale remain unclear. In this study, typical vegetation cover types along various water levels were chosen to investigate the effects of water level and vegetation cover on the microbial community and functional genes in the Lake Erhai littoral zone. The results showed that water level fluctuations influenced oxygen and nitrogen compound contents due to oxic–anoxic alternations and intensive material exchange. Meanwhile, vegetation cover affected the organic matter and total nitrogen content through plant residues and root exudation supplying exogenous carbon and nitrogen. Along the hydrological gradient, the high microbial diversity and abundant microbes related to nitrogen cycling were observed in interface sediments. It was attributed to the alternating aerobic–anaerobic environments, which filtered adaptable dominant phyla and genera. The abundances of amoA AOA, nirS, and amx were higher than those of the other genes and were strongly related to flooding days and water content. In conclusion, water level fluctuations and vegetation type jointly affect microbial community structure and nitrogen-related functional genes. Full article

This paper presents a comparative analysis of the laser operating power (P1 and P2) and synthetic leather thickness to achieve the optimal quality of components in the airbag area, produced through micro-perforation laser processing. Within the study, various laser power settings and material thicknesses were investigated to determine the combinations that ensure the best component performance. The experimental results indicate that setting the laser to 25% of its total power (P1, P2) of two kilowatts (kW) represents the optimal parameter setup to achieve parts of superior quality. This configuration is not significantly influenced by the material thickness, suggesting important versatility in practical applications. The overall results indicate the significant influence of the laser power level on micro-perforation processing. The normal analysis of means (ANOM) and factorial design (DOE) provide significant evidence for an interaction, highlighting that the effects of one laser power factor depend on the level of the other laser power factor. These findings are essential in improving production processes, as they allow for the manufacture of airbag components with high precision and consistency, minimizing the risks of material deformation or damage. Thus, not only is compliance with safety standards ensured, but the economic efficiency of the production process is also enhanced. Full article

The study of Ammoides pusilla, a Tunisian medicinal plant, explored its chemical composition and biological activities, highlighting its under-exploited therapeutic potential. The essential oil, obtained by steam distillation, reveals twenty major compounds, including perilic aldehyde, β-phellandrene, and o-cymene. Two new natural constituents were identified in the cyclohexane extract and four in the dichloromethane extract. DPPH and ABTS tests showed that methanol extract exhibited the highest antioxidant activity, giving values of 78.9% and 65.5%, respectively, at 50 µg/mL. Its anti-diabetic activity (IC50 = 25.0 µg/mL) exceeds that of acarbose. The anti-SOD activity of methanol extract also showed promise, at 73.3% at 50 µg/mL. Essential oil and ethyl acetate extract showed notable inhibition of xanthine oxidase activity, reaching 69.0%. In addition, the essential oil demonstrated strong anti-AChE (63.23% at 50 µg/mL) and anti-inflammatory (IC50 = 31.0 µg/mL) activity. In terms of cytotoxicity, the methanol extract was effective against the HCT116 cell line (IC50 = 20.9 µg/mL), and all extracts showed activity against MCF7, OVCAR-3, and IGROV-1 cells, with IC50 values ranging from 4.0 to 25.0 µg/mL. This result underlines the potential of Ammoides pusilla extracts as important sources of bioactive compounds for therapeutic applications. Further research is needed to fully exploit these activities in drug development. Full article