Cleaner Engineering and Technology最新文献

In the present work, a new configuration of the three-part blade (3-PB) Vertical Axis Wind Turbine (VAWT) is introduced. This new configuration is designed to further improve the aerodynamic performance of the 3-PB VAWT by tilting all three parts of every single blade along its central chord line. An optimization process is conducted to find the best tilt angle of blade parts in order to maximize the average total torque coefficient. The optimization process is applied to reference 3-PB VAWT with the help of a Genetic Algorithm (GA) and Artificial Neural Network (ANN) using the solutions of three-dimensional Reynolds averaged Navier-Stokes (RANS) equations at wind speed of $7$ m/s and tip speed ratios from 0.44 to 1.77. Having analyzed different sets of tilt angles, a configuration with tilt angles of 30°, 31° $\text{,}$ and 30° with respect to part 1, 2, and 3 was detected to be the best choice. The tilted 3-PB VAWT shows promising improvements in most tip speed ratios. Among them, a maximum improvement of 42.99% on the average of the total torque coefficient occurred at tip speed ratio of 0.89.

This research explores a sustainable approach for fabricating high-performance nanodiamond composite (NDC) hard coatings for dry machining. Aiming to address limitations in conventional coatings, such as environmental concerns, restricted film thickness, and compromised performance. The study utilizes Coaxial Arc Plasma Deposition (CAPD), a clean and efficient technique, to deposit thick (10 μm) NDC films directly on WC−Co substrates without chemical etching. Compared to traditional Chemical Vapor Deposition (CVD), CAPD offers significant advantages: lower temperature deposition, faster growth rate, and precise control over film thickness and morphology. The resulting NDC films boast exceptional durability due to their unique nanostructure, diamond nanocrystallites embedded in an amorphous carbon matrix. The addition of Al-interlayers (100–500 nm thickness) optimizes film properties. The optimal interlayer at 100 nm thickness not only mitigates the catalytic effects of Co but also enhances film hardness (50.4–58 GPa), Young's modulus (516–613.75 GPa), and adhesion (13–18.5 N) compared to films without an interlayer. Notably, the 100 nm Al-interlayer triples the deposition rate to 3.3 μm/h, achieving the desired thickness for effective hard coatings. The high density of grain boundaries within the films allows for exceptional stress release, enabling this increased thickness. Furthermore, these grain boundaries and the graphitic phase contribute to the film's superior tribological performance – a low coefficient of friction (0.1) and minimal wear rate (1.5 × 10⁻⁷ mm³/N⋅m) under dry machining conditions. These findings demonstrate the immense potential of CAPD-deposited NDC films as a sustainable alternative for advanced cutting tools, promoting environmental responsibility, economic viability, and energy efficiency.

Increased societal awareness, stakeholder pressure, stringent environmental norms, and the need to sustain in the competitive business market have demanded environment-friendly manufacturing practices from the industrial communities. Sustainable manufacturing (SM) practices have gained widespread attention as they aim to balance economic, environmental, and social activities of organizations. However, still there is a lacuna in understanding the concept of SM practices and there is a need to monitor the developments related to SM practices. Thus, there is a need to conduct a comprehensive review study for an improved understanding of the progress of SM practices. Accordingly, this study aims to identify various strategies followed by organizations for implementing SM practices. To identify various strategies, 89 articles were selected from the SCOPUS database (published between 2012 and 2022). These 89 articles were selected by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, a systematic literature review (SLR) technique. The selected articles were investigated based on year, journals, country, research methods, focused industry, and techniques followed. Bibliometric and network analysis were performed to establish cluster domains and to identify evolving research areas. Bibliometric analysis reveals that currently, the industrial communities is emphasizing circular economy models for SM practices. Network analysis identifies six domains of SM practices: lean manufacturing, renewable energy adoption, green manufacturing, life cycle assessment, zero waste manufacturing practices, and circular economy model. To conclude, the important contribution of this study is that it tracks the progress of SM practices over the years and highlights current SM practices.

The rise in abandoned oil wells across the globe poses a serious environmental and public health risk. These wells, which are frequently abandoned by defunct corporations or owing to regulatory gaps, pose substantial risks. They have the potential to leak methane, a potent greenhouse gas, and contaminate groundwater. Researchers estimate that there are between 2 and 3 million abandoned oil and gas wells in the United States. Out of these, over 117,000 wells, spread across 27 states, are classified as “orphaned”, and lack an identifiable party responsible for managing leakage or pollution risks. The escalating number of abandoned oil wells in the United States presents a dual challenge and opportunity in the realm of renewable energy. The global utilization of geothermal energy is on the rise, with approximately 72 countries harnessing this resource for various applications. About 24 of these countries generate electricity using geothermal energy through binary or flash cycle methods. The United States leads in geothermal electricity production, generating approximately 17,917 GWh annually. Global raise in geothermal energy utilization provides presents an opportunity to repurpose abandoned oil wells for geothermal energy production especially in the United States. These wells, often still possessing high temperatures and temperature gradients, can be converted into valuable geothermal resources, thus providing a sustainable energy solution and addressing the environmental hazards posed by the abandoned wells. This paper critically examines the feasibility of repurposing these wells for geothermal energy production, a strategy that offers a promising solution to both environmental hazards and the need for sustainable energy sources. Focusing on the technical, economic, and social dimensions, we present a comprehensive analysis that includes a case study of the Williston Basin in North Dakota, highlighting its potential for geothermal exploitation. Our approach employs Fourier's law of conduction to estimate the temperature at the bottom of selected wells. We address the critical challenges in this endeavor, ranging from ensuring the mechanical integrity of aging wells to navigating the economic and social implications of their repurposing. Our findings suggest that while significant challenges exist, especially in retrofitting old wells for new uses and garnering stakeholder consensus, the conversion of abandoned oil wells into geothermal energy sources is a viable and environmentally beneficial path forward. Finally representing a detailed exploration of their various potential geothermal and various applications This research contributes to the growing body of literature on sustainable energy solutions, offering practical insights and guidelines for future field implementations in the transition from fossil fuels to renewable energy sources.

The environmental impact is a strong incentive for the development of upcycling processes for textile waste. However, toxic chemicals may occur in both brand-new textiles and post-consumer garments, and the chemical transfer in such routes is important to investigate. The present study applied non-target screening and quantification with liquid chromatography/mass spectrometry to follow the fate of hazardous chemicals from post-consumer polycotton garments to a new material, cellulose nanocrystals, in a chemical upcycling utilizing strongly acidic conditions. The majority of hazardous chemicals detected within the process were found to be transferred to a residual of polyester material and not to the enriched cellulose. However, phthalates were found to be mainly attached to the cellulose nanocrystals. The detected total concentration, in this case, was below 5 μg/g, at least 200 times lower than the limit set by the European Union. This indicates the importance of monitoring and controlling the phthalate content in the starting material of the process, i.e., the post-consumer garments. The chemical release into the process waste effluent could be estimated based on water solubility data for chemicals under the applied conditions. Three compounds, the water-repellent substance perfluorooctanesulfonic acid and the dyes Crystal Violet and Victoria Pure Blue, were almost entirely transferred into the process waste effluent. Although the levels detected were very low in the present pilot process, their presence eventually indicates the need for wastewater purification at further upscaling, depending on the exposure and dose in relation to toxicological relevant thresholds.

This study aims to evaluate the potential of polyethylene glycol (PEG 6000), a recycled material, as an additive to improve unfired clay bricks. By proposing a sustainable alternative to traditional methods potentially linked to medical waste. This research explores the physicochemical, mechanical and thermal properties of unfired clay bricks modified by different contents of PEG 6000 (0%, 1%, 3%, 7%, 15% and 20% by weight) according to the standard NM 13.1 0.0442005. The testing methods comply with recognized building sector standards (Belgian NBN EN 771-3+A1 and American ASTM C675-17). The clay used was extracted from Berrechid city and it is identified as kaolinite and some trace of illite, which has non-swelling properties. The incorporation of PEG 6000 into the unfired clay bricks has notably reduced the porosity rate from 3.91 % to 1.21 %, an improvement of 69 % compared to the reference sample, leading to a decrease in the rate of capillary water absorption. The bulk density of the bricks has slightly decreased to 1670.07 kg/m³, which still allowed them to be classified as light bricks. The incorporation of 7% of PEG 6000 increased compressive strength and flexural strength up to 15.98 MPa and 0.959 KN respectively, an improvement of 63.23 % compared to the reference sample, making them suitable for the construction of interior and exterior walls according to the standard NBN EN 771-3+A1. However, thermal conductivity and specific heat capacity have been improved by 42.22 % compared to the reference sample, reaching 0.26 W/m.K and 0.89 kJ/kg.K respectively. Optimization showed that 7% of PEG 6000 is the optimal percentage for manufacturing high-performance bricks, taking into account all properties studied previously. Moreover, the simulations carried out by the TRANSYS software suggest significant energy gains in terms of insulation, achieving up to 58.33% energy savings. In essence, this research demonstrates the potential of PEG 6000 as a sustainable additive for unfired clay bricks, offering improved properties and promising energy efficiency benefits.

One of the main challenges in ethanol production within alcohol industries is the management of vinasse, a voluminous and highly toxic waste. This demands the search for alternatives for its reprocessing and disposal since its release into the environment results in soil and water pollution, leading to an unhealthy environment, ecological imbalances, and harm to wildlife. Given the relevance of this issue, the main objective of this study was to research patents in leading databases focused on vinasse treatment. The results were then correlated with an analysis of publications on vinasse application in new products and processes from January 1990 to December 2021. Additionally, we conducted a research profile analysis using three software tools (VOSViewer, CiteSpace, and CitNetExplorer) to extract citation networks, identify the main research groups, and comprehend the evolution of vinasse-related research over time. The results showed that most frequent applications are: i) biofuel production; ii) treatment; iii) recovery of organic compounds; iv) enzymatic hydrolysis; v) bioremediation; vi) fertilizer. With this, articles were searched for the investigation of innovations in the sugar-cane ethanol production chain. Most articles focus on the treatment of vinasse using microorganisms, in addition to the reuse of this effluent as a fertilizer. Thus, this study contributes to the presentation of the main works in the field and the literature regarding the use of vinasse and pointing out the current challenges to be overcome.

This paper presents a novel approach for upgrading utility systems by integrating absorption cooling systems using R-curve analysis. The key contributions include a comprehensive methodology for drawing the R-curve, determining priority paths, and optimizing the system without additional capital costs; a step-by-step case study illustrating the process of integrating two absorption chillers and analyzing their impact on cogeneration efficiency and the R-curve; equations for calculating cogeneration efficiency and power efficiency for different turbine paths to prioritize the most efficient paths; and findings revealing that integrating absorption chillers can significantly impact system performance, potentially increasing or decreasing cogeneration efficiency depending on the specific system. The proposed approach enables engineers to optimize utility systems by leveraging existing equipment and integrating absorption cooling efficiently, with the R-curve analysis providing a powerful tool for visualizing and optimizing the system to achieve the best balance of power, cooling, and heating. The findings demonstrate that careful analysis and optimization of the utility system using R-curve techniques can unlock significant energy savings and emissions reductions by prioritizing the most efficient turbine paths and integrating absorption cooling optimally.

Transportation is one of the sectors with the highest CO₂ emissions, accounting for 23% globally and significantly contributing to climate change. To address this challenge, the authorities have proposed new stringent policies that lead to decarbonization. From this perspective, this work proposes a multi-scenario analysis for the electrification of a fleet of private users. The scenarios differ on the type of charging mode adopted: slow charging (charging modes 1 and 2) and fast charging (charging modes 3 and 4). The model aims to identify the percentage of potential users who can shift from Internal Combustion Engine (ICE) to Electric Vehicles (EVs) in different scenarios. Furthermore, the model will highlight the average expenditure of users for charging, highlighting how the cost of energy could be a driver for the electrification of the sector. Finally, the model will allow us to evaluate the savings of up to 220 tons of CO₂/year thanks to the electrification of the sector with Long Range vehicles, in best case scenario. The use of a multi-scenario analysis allowed several possible electrification solutions to be explored, highlighting the strengths and weaknesses of the charging mode used, supported by quantitative results. This data-driven approach allows us to identify optimal locations for public charging stations in region of northern Italy region, where the data was sourced, which will help to encourage the switch to EVs.