Processes

25 pages, 4652 KiB

Open AccessArticle

The Investigation of Two-Phase Expansion Performance with Indicator Diagram in a Twin-Screw Expander

by Yang Ma, Yaodong Zhou and Zhenkun Zhu

Processes 2023, 11(6), 1862; https://doi.org/10.3390/pr11061862 - 20 Jun 2023

Cited by 1 | Viewed by 1139

Volumetric expanders are proven to be more suitable for small-scale waste heat recovery applications because of their simplicity, reliability, lower rotational speed and lower cost. Unlike turbines, volumetric expanders can work in the two-phase fluid state, which broadens their application fields. To investigate [...] Read more.

Volumetric expanders are proven to be more suitable for small-scale waste heat recovery applications because of their simplicity, reliability, lower rotational speed and lower cost. Unlike turbines, volumetric expanders can work in the two-phase fluid state, which broadens their application fields. To investigate the two-phase performance of volumetric expanders, a specific twin-screw expander was chosen and modeled. The leakage loss and the suction pressure loss were primary concerns in this research. The two-phase expansion process in the expander is presented in detail using the developed mathematical model with an indicator diagram. The influence of several factors, including inlet vapor quality, rotational speed and intake pressure, are investigated. The influence mechanism of the vapor phase and the liquid phase on expander performance is clarified. In brief, this paper presents an illustrative understanding of the two-phase expansion process in twin-screw expanders. Full article

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Graphical abstract

16 pages, 6730 KiB

Open AccessFeature PaperArticle

Numerical Investigations of Heat Transfer and Fluid Flow Characteristics in Microchannels with Bionic Fish-Shaped Ribs

by Quanyue Gao, Haibo Zou and Juan Li

Processes 2023, 11(6), 1861; https://doi.org/10.3390/pr11061861 - 20 Jun 2023

Viewed by 901

Abstract

Microchannel cooling technology is an effective method to solve local thermal stacking. In this paper, four innovative microchannels with bionic fish-shaped rib arrangements (CM-O, CM-R, CM-H, and CM-G) are designed by imitating geese and fish clusters. The heat transfer and flow characteristics of [...] Read more.

Microchannel cooling technology is an effective method to solve local thermal stacking. In this paper, four innovative microchannels with bionic fish-shaped rib arrangements (CM-O, CM-R, CM-H, and CM-G) are designed by imitating geese and fish clusters. The heat transfer and flow characteristics of the microchannels are simulated numerically at different Reynold’s numbers (Re = 200 − 1600). The liquid water temperature and flow field in the four innovative microchannels with bionic ribs are analyzed. The results show that the ribs’ arrangement has an influence on the thermal performance of microchannels. Compared to the smooth microchannel (CM), the of the

N_{u}

microchannels with the bionic fish-shaped ribs increases by 33.00–53.26% while the

f_{a v e}

increases by 28.63–34.93% at Re = 1200. The vortices around the ribs are clearly observed which improves the temperature gradient. The performance evaluation criterion (PEC) of CM-H is higher than that of the others. This indicates that the rib arrangement of CM-H is superior for heat dissipation application. Full article

(This article belongs to the Special Issue Energy and Water Treatment Processes)

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15 pages, 1857 KiB

Open AccessArticle

Synthesis and Biological Evaluation of α-Tocopherol Derivatives as Potential Anticancer Agents

by Aneta Baj, Lucie Rárová, Artur Ratkiewicz, Miroslav Strnad and Stanislaw Witkowski

Processes 2023, 11(6), 1860; https://doi.org/10.3390/pr11061860 - 20 Jun 2023

Viewed by 1313

Abstract

α-Tocopheryl succinate (α-TS) and α-tocopheryloxyacetic acid (α-TEA) are potent inducers of apoptosis in cancer cells and efficient suppressors of tumors in experimental model cancer cell lines. They exhibit selective cytotoxicity against tumor cells and very limited or no toxicity toward nonmalignant cells. In [...] Read more.

α-Tocopheryl succinate (α-TS) and α-tocopheryloxyacetic acid (α-TEA) are potent inducers of apoptosis in cancer cells and efficient suppressors of tumors in experimental model cancer cell lines. They exhibit selective cytotoxicity against tumor cells and very limited or no toxicity toward nonmalignant cells. In the present work, a series of new α-tocopherol derivatives were synthesized as analogs of α-TS and α-TEA. The cytotoxic activity of obtained compounds was tested using three human cancer cell lines, including chronic lymphoblastic leukemia (CEM), breast adenocarcinoma (MCF7), cervical adenocarcinoma (HeLa), and normal human fibroblasts (BJ). The introduction of an alkyl substituent into the ether-linked acetic acid moiety in α-TEA increased anticancer activity. α-Tocopheryloxy-2-methylpropanoic acid with two additional geminal methyl groups was more active against CEM cells compared to α-TEA and non-toxic to normal cells. In order to acquire a deeper understanding of the biological activity of synthesized compounds, a molecular docking study was also conducted. Our research confirmed that vitamin E derivatives are interesting and valuable compounds in terms of their potential therapeutic use as anticancer agents. Full article

(This article belongs to the Special Issue Natural Compounds Applications in Drug Discovery and Development)

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15 pages, 1711 KiB

Open AccessArticle

Observer-Based Control of Inductive Wireless Power Transfer System Using Genetic Algorithm

by Mahmoud Abdelrahim and Dhafer Almakhles

Processes 2023, 11(6), 1859; https://doi.org/10.3390/pr11061859 - 20 Jun 2023

Viewed by 716

Abstract

In this paper, we studied the feedback stabilization of an inductive power transfer system based on available output measurement. The proposed controller relies on a full-order state observer in order to estimate the unmeasured state. The control design problem is challenging due to [...] Read more.

In this paper, we studied the feedback stabilization of an inductive power transfer system based on available output measurement. The proposed controller relies on a full-order state observer in order to estimate the unmeasured state. The control design problem is challenging due to the large dimension of the closed-loop system, which requires too many tuning parameters to be determined when conventional control methods are employed. To solve this issue, we propose an LQR methodology based on a genetic algorithm such that the weighing coefficients of the cost function matrices can be automatically computed in an optimized manner. The proposed approach combines the method of eigenstructure assignment and the LQR technique in order to design both the controller and the observer gain matrices. The design methodology provides a systematic way to compute the parameters of the LQR technique for a wireless power transfer system in an optimized manner, which can be a useful design tool for many other applications. The effectiveness of the approach was verified by numerical simulation on the dynamic model of the wireless power transfer system. The results show that the proposed design outperforms conventional design methods in terms of a better performance and reduced design iterations effort. Full article

(This article belongs to the Topic Modeling, Optimization, and Control of Energy Systems)

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18 pages, 5005 KiB

Open AccessArticle

Thermo-Hydraulic Management System Employing Single-Phase Water Flow through Microchannels with Micro-Inserts Added Aiming for Performance Improvement

by Shailesh Ranjan Kumar and Satyendra Singh

Processes 2023, 11(6), 1858; https://doi.org/10.3390/pr11061858 - 20 Jun 2023

Viewed by 678

Abstract

A microchannel heat exchanger effectively evacuates heat from a confined space. This paper attempts to gain insight into the combinatorial repercussions of simultaneously coupling two factors that affect a microchannel’s performance, of which channel size and micro-insert complexity are the two main contributors. [...] Read more.

A microchannel heat exchanger effectively evacuates heat from a confined space. This paper attempts to gain insight into the combinatorial repercussions of simultaneously coupling two factors that affect a microchannel’s performance, of which channel size and micro-insert complexity are the two main contributors. With water as the working fluid, an ANSYS-based numerical analysis was carried out for two distinct channel sizes, 1 and 2 mm, both with and without micro-inserts. The Reynolds numbers varied between 125 and 4992 and between 250 and 9985 for the 1 and 2 mm channels, respectively. For the 2 mm diameter channel, adding micro-inserts raised the overall pressure drop with increased Reynolds number. The inclusion of micro-inserts increased the pressure drop in the 1 mm channel at first, and thereafter the pressure drop decreased. Incorporating micro-inserts into the channel resulted in enhanced heat transfer. The trade-off between enhanced heat transfer performance and a larger pressure drop was calculated by evaluating the channel’s overall performance using the thermal performance factor. Micro-inserts were found to be most useful for improving overall performance in the low-to-moderate Reynolds number range, and their effectiveness increased with decreasing channel size. Changing the channel diameter and structure of the design can improve heat transmission through microchannels. Full article

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22 pages, 6277 KiB

Open AccessArticle

Novel Copper Oxide Phyto-Nanocatalyst Utilized for the Synthesis of Sustainable Biodiesel from Citrullus colocynthis Seed Oil

by Aqsa Aziz, Mushtaq Ahmad, Muhammad Zafar, Abdel-Rhman Z. Gaafar, Mohamed S. Hodhod, Shazia Sultana, Mohammad Athar, Fethi Ahmet Ozdemir, Trobjon Makhkamov, Akramjon Yuldashev, Oybek Mamarakhimov, Maxsuda Nizomova, Salman Majeed and Bisha Chaudhay

Processes 2023, 11(6), 1857; https://doi.org/10.3390/pr11061857 - 20 Jun 2023

Cited by 15 | Viewed by 1414

Abstract

The green chemistry method for nanocatalyst synthesis along with environmentally feasible non-edible sources are promising alternatives to fossil fuels. The current study focuses on the synthesis of copper oxide phyto-nanocatalyst and the identification of a new renewable feedstock, Citrullus colocynthis, to reduce [...] Read more.

The green chemistry method for nanocatalyst synthesis along with environmentally feasible non-edible sources are promising alternatives to fossil fuels. The current study focuses on the synthesis of copper oxide phyto-nanocatalyst and the identification of a new renewable feedstock, Citrullus colocynthis, to reduce environmental pollution. The highest biodiesel yield (95%) was obtained under optimum conditions of a 1:8 oil-to-methanol ratio and reaction temperature of 85 °C for 120 min with a 0.365 wt% catalyst concentration. The phyto-nanocatalyst was synthesized using seed oil cake after extracting oil with the salt of copper (copper oxide). The catalyst was then subjected to various analyses, namely, EDX, FT-IR, SEM, and XRD. The catalyst was proved to be efficient and effective after being reused five times and still there was a very small difference in biodiesel yield. All the analyses also show sustainable and stable results. Thus, copper oxide phyto-nanocatalyst with non-edible Citrullus colocynthis proved to be highly effective, sustainable, and a better alternative source to the future biodiesel industry. Full article

(This article belongs to the Section Environmental and Green Processes)

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17 pages, 4534 KiB

Open AccessArticle

Temperature–Electrokinetic Co-Driven Perfluorooctane Sulfonic Acid (PFOS) Adsorption on Geo-Adsorbents

by Yuzhou Yin, Yongping Shan, Dong Ma, Liuqing Yang, Mingxiu Zhan, Ping Liu, Benzhen Lou, Bo Zhang, Wentao Jiao and Lichu Yin

Processes 2023, 11(6), 1856; https://doi.org/10.3390/pr11061856 - 20 Jun 2023

Viewed by 881

Abstract

Per- and polyfluoroalkyl substances (PFAS) have concerned the public due to their worldwide distribution and the threat they pose to drinking water safety and human health. Temperature and DC field-induced electroosmotic flow (EOF) are powerful tools to regulate organic contaminant adsorption and control [...] Read more.

Per- and polyfluoroalkyl substances (PFAS) have concerned the public due to their worldwide distribution and the threat they pose to drinking water safety and human health. Temperature and DC field-induced electroosmotic flow (EOF) are powerful tools to regulate organic contaminant adsorption and control PFOS (as a typical PFAS) transport in porous media. However, the co-driven mechanisms of temperature–electrokinetic transport of contaminants are still unclear. Here, we investigated the synergistic mechanisms of temperature–electrokinetic co-driven PFOS adsorption on zeolite and activated carbon as model geo-adsorbents. We found that DC fields increased PFOS adsorption on activated carbon by up to 19.8%, while they decreased PFOS adsorption on zeolite by up to 21.4%. Increasing the temperature decreased the adsorption of PFOS by activated carbon and zeolite. The temperature and electrokinetic synergistically drive EOF velocity to control PFOS adsorption. Synergistic mechanisms of temperature–electrokinetic regulated kinetic and temperature-regulated thermodynamic (the Gibbs free energy change ΔG) and kinetic (liquid viscosity) under various temperatures and DC field situations were analyzed with models. A kinetic approach interlinking viscosity, EOF velocity, and the kinetic adsorption constants was established to interpret the synergistic mechanisms which can be further adopted to estimate temperature–electrokinetic induced PFOS adsorption benefits to mineral and carbonaceous adsorbents. We concluded that such kinetic regulation may provide support for controlling the transmission of PFOS. Full article

(This article belongs to the Special Issue Wastewater Treatment: Control, Removal and Separation Processes)

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25 pages, 9371 KiB

Open AccessArticle

A Feasibility Study on the Use of Injection Molding Systems for Mass Production of 100W Class Wind Turbine Blades

by Joongseon Kim, Upendra Tuladhar, Deokkeun Je, Marinus Mieremet, Joonho Baek, Hoseong Ji and Seokyoung Ahn

Processes 2023, 11(6), 1855; https://doi.org/10.3390/pr11061855 - 20 Jun 2023

Cited by 1 | Viewed by 1295

Abstract

A feasibility study on the mass production of a small wind turbine blade using an injection molding process was conducted. The blade was divided into three sections suitable for injection molding, and the mold was designed and analyzed using Moldflow CAE S/W. The [...] Read more.

A feasibility study on the mass production of a small wind turbine blade using an injection molding process was conducted. The blade was divided into three sections suitable for injection molding, and the mold was designed and analyzed using Moldflow CAE S/W. The optimal feedstock material was selected through comparison and analysis of three candidate materials. A mold was manufactured to test the injection molding process and evaluate related parameters. The resulting blade was assembled with other components, and a generator was installed to assess its durability, safety, and performance under various conditions. The results indicated the feasibility of producing a blade for a small wind turbine through injection molding, which predicted higher productivity and lower costs compared to traditional manufacturing methods that rely heavily on manual labor. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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15 pages, 3903 KiB

Open AccessArticle

Comparison and Analysis of Several Quantitative Identification Models of Pesticide Residues Based on Quick Detection Paperboard

by Yao Zhang, Qifu Zheng, Xiaobin Chen, Yingyi Guan, Jingbo Dai, Min Zhang, Yunyuan Dong and Haodong Tang

Processes 2023, 11(6), 1854; https://doi.org/10.3390/pr11061854 - 20 Jun 2023

Cited by 1 | Viewed by 986

Abstract

Pesticide residues have long been a significant aspect of food safety, which has always been a major social concern. This study presents research and analysis on the identification of pesticide residue fast detection cards based on the enzyme inhibition approach. In this study, [...] Read more.

Pesticide residues have long been a significant aspect of food safety, which has always been a major social concern. This study presents research and analysis on the identification of pesticide residue fast detection cards based on the enzyme inhibition approach. In this study, image recognition technology is used to extract the color information RGB eigenvalues from the detection results of the quick detection card, and four regression models are established to quantitatively predict the pesticide residue concentration indicated by the quick detection card using RGB eigenvalues. The four regression models are linear regression model, quadratic polynomial regression model, exponential regression model and RBF neural network model. Through study and comparison, it has been shown that the exponential regression model is superior at predicting the pesticide residue concentration indicated by the rapid detection card. The correlation value is 0.900, and the root mean square error is 0.106. There will be no negative prediction value when the expected concentration is near to 0. This gives a novel concept and data support for the development of image recognition equipment for pesticide residue fast detection cards based on the enzyme inhibition approach. Full article

(This article belongs to the Special Issue Artificial Intelligence in the Process Industry)

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13 pages, 2406 KiB

Open AccessArticle

Optimization Design of an Intermediate Fluid Thermoelectric Generator for Exhaust Waste Heat Recovery

by Wei Zhang, Wenjie Li, Shuqian Li, Liyao Xie, Minghui Ge and Yulong Zhao

Processes 2023, 11(6), 1853; https://doi.org/10.3390/pr11061853 - 20 Jun 2023

Cited by 2 | Viewed by 1023

Abstract

The intermediate fluid thermoelectric generator (IFTEG) represents a novel approach to power generation, predicated upon the principles of gravity heat pipe technology. Its key advantages include high-power output and a compact module area. The generator’s performance, however, is influenced by the variable exhaust [...] Read more.

The intermediate fluid thermoelectric generator (IFTEG) represents a novel approach to power generation, predicated upon the principles of gravity heat pipe technology. Its key advantages include high-power output and a compact module area. The generator’s performance, however, is influenced by the variable exhaust parameters typical of automobile operation, which presents a significant challenge in the design process. The present study establishes a mathematical model to optimize the design of the IFTEG. Our findings suggest that the optimal module area sees substantial growth with an increase in both the exhaust heat exchanger area and the exhaust flow rate. Interestingly, the optimal module area appears to demonstrate a low sensitivity to changes in exhaust temperature. To address the challenge of determining the optimal module area, this study introduces the concept of peak power deviation. This method posits that any deviation from the optimal module area results in an equivalent power deviation. For instance, with an exhaust heat exchanger area of 1.6 m², the minimum peak power deviation is 27.5%, corresponding to a design module area of 0.124 m². As such, the actual output power’s deviation from the maximum achievable output power will not exceed 27.5% for any given set of exhaust parameters. This study extends its findings to delineate the relationship between the optimal design module area and the exhaust heat exchanger area. These insights could serve as a useful guide for the design of future power generators. Full article

(This article belongs to the Special Issue Advances in Waste Heat Recovery Using Thermoelectric Generators)

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58 pages, 3843 KiB

Open AccessReview

A Review of Third Generation Solar Cells

by N. Shah, A. A. Shah, P. K. Leung, S. Khan, K. Sun, X. Zhu and Q. Liao

Processes 2023, 11(6), 1852; https://doi.org/10.3390/pr11061852 - 20 Jun 2023

Cited by 12 | Viewed by 8460

Abstract

Third-generation solar cells are designed to achieve high power-conversion efficiency while being low-cost to produce. These solar cells have the ability to surpass the Shockley–Queisser limit. This review focuses on different types of third-generation solar cells such as dye-sensitized solar cells, Perovskite-based cells, [...] Read more.

Third-generation solar cells are designed to achieve high power-conversion efficiency while being low-cost to produce. These solar cells have the ability to surpass the Shockley–Queisser limit. This review focuses on different types of third-generation solar cells such as dye-sensitized solar cells, Perovskite-based cells, organic photovoltaics, quantum dot solar cells, and tandem solar cells, a stacked form of different materials utilizing a maximum solar spectrum to achieve high power conversion efficiency. Apart from these solar cells, other third-generation technologies are also discussed, including up-conversion, down-conversion, hot-carrier, and multiple exciton. This review provides an overview of the previous work in the field, alongside an introduction to the technologies, including their working principles and components. Advancements made in the different components and improvements in performance parameters such as the fill factor, open circuit voltage, conversion efficiency, and short-circuit current density are discussed. We also highlight the hurdles preventing these technologies from reaching commercialization. Full article

(This article belongs to the Section Energy Systems)

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23 pages, 2096 KiB

Open AccessArticle

Comparative Analysis of Paddy Harvesting Systems toward Low-Carbon Mechanization in the Future: A Case Study in Sri Lanka

by P. D. Kahandage, S. D. S. Piyathissa, Reza Ariesca, Namgay, Riaru Ishizaki, E. J. Kosgollegedara, G. V. T. V. Weerasooriya, Tofael Ahamed and Ryozo Noguchi

Processes 2023, 11(6), 1851; https://doi.org/10.3390/pr11061851 - 19 Jun 2023

Cited by 1 | Viewed by 1470

Abstract

In this study, three paddy harvesting systems, manual harvesting of paddy (MHP), reaper harvesting of paddy (RHP), and combine harvesting of paddy (CHP), were evaluated considering field capacities, field efficiencies, time and fuel consumption, mechanization indices, greenhouse gas emissions, straw availability, and direct [...] Read more.

In this study, three paddy harvesting systems, manual harvesting of paddy (MHP), reaper harvesting of paddy (RHP), and combine harvesting of paddy (CHP), were evaluated considering field capacities, field efficiencies, time and fuel consumption, mechanization indices, greenhouse gas emissions, straw availability, and direct and indirect costs. Field experiments were conducted in the North Central Province of Sri Lanka. The effective field capacity, field efficiency and fuel consumption of the combine harvester were 0.34 hah⁻¹, 60.8%, and 34.1 Lha⁻¹, respectively, and those of the paddy reaper were 0.185 hah⁻¹, 58.2%, and 3.8 Lha⁻¹, respectively. The total time consumed by MHP, RHP, and CHP were 76.05 hha⁻¹, 39.76 hha⁻¹, and 2.94 hha⁻¹, respectively. The highest energy utilization was recorded by the CHP, at 1851.09 MJha⁻¹, while MHP recorded the lowest at 643.20 MJha⁻¹. The direct cost of the MHP was 1.50 and 1.52 times higher than those of the CHP and RHP, respectively. MHP recorded the lowest greenhouse gas emissions (32.94 kgCO₂eqha⁻¹), while CHP recorded the highest (176.29 kgCO₂eqha⁻¹). The RHP exhibited an intermediate level in all aspects. Although the CHP has higher field performance and direct costs, it has higher GHG emissions and indirect costs. Therefore, an optimum level of mechanization should be introduced for the long-term sustainability of both the environment and farming. Full article

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23 pages, 10617 KiB

Open AccessFeature PaperArticle

Operating and Thermal Efficiency Boundary Expansion of Argon Power Cycle Hydrogen Engine

by Weiqi Ding, Jun Deng, Chenxu Wang, Renjie Deng, Hao Yang, Yongjian Tang, Zhe Ma and Liguang Li

Processes 2023, 11(6), 1850; https://doi.org/10.3390/pr11061850 - 19 Jun 2023

Cited by 4 | Viewed by 1061

Abstract

The efficiency enhancement of argon power cycle engines through theoretical means has been substantiated. However, the escalation of in-cylinder temperatures engenders abnormal combustion phenomena, impeding the augmentation of compression ratios and practical efficiency. This study presents a comprehensive investigation employing experimental and simulation [...] Read more.

The efficiency enhancement of argon power cycle engines through theoretical means has been substantiated. However, the escalation of in-cylinder temperatures engenders abnormal combustion phenomena, impeding the augmentation of compression ratios and practical efficiency. This study presents a comprehensive investigation employing experimental and simulation techniques, aiming to extend the boundaries of thermal efficiency and operational capabilities for hydrogen-powered argon cycle engines. The impact of hydrogen direct injection, intake boost, and port water injection is evaluated in conjunction with an argon power cycle hydrogen engine. The hydrogen direct injection, particularly at an engine speed of 1000 rpm, significantly increases the indicated mean effective pressure from 0.39 MPa to 0.72 Mpa, surpassing the performance of the port hydrogen injection. Manipulating the hydrogen direct injection timing results in the formation of a stratified mixture, effectively attenuating the combustion rate, and resolving the issue of excessively rapid hydrogen combustion within an Ar/O₂ environment. The implementation of super lean combustion, combined with intake-boosting, achieves a maximum gross indicated thermal efficiency of 57.89%. Furthermore, the port water injection proves to be an effective measure against knock, broadening the operational range of intake-boosted conditions. Notably, the maximum gross indicated thermal efficiency recorded for the port water injection group under intake-boosted conditions reaches 59.35%. Full article

(This article belongs to the Special Issue Control of Injector Spray Characteristics and Synthetic Fuels)

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30 pages, 5136 KiB

Open AccessFeature PaperReview

Existing Stature and Possible Outlook of Renewable Power in Comprehensive Electricity Market

by Shreya Shree Das, Jayendra Kumar, Subhojit Dawn and Ferdinando Salata

Processes 2023, 11(6), 1849; https://doi.org/10.3390/pr11061849 - 19 Jun 2023

Cited by 1 | Viewed by 1075

Abstract

The massive growth in power demand and the sharp decay in the availability of conventional energy sources forces society to move toward renewable power consumption. The rise in renewable energy utilization is one of the greatest strategies involved in making the environment clean, [...] Read more.

The massive growth in power demand and the sharp decay in the availability of conventional energy sources forces society to move toward renewable power consumption. The rise in renewable energy utilization is one of the greatest strategies involved in making the environment clean, green, and emission-free. The investment cost is slightly high for this kind of resource, but their running costsare very minimal, which encourages power producers to invest in renewable power plants. Power producers always focus on their economic profit and possible feasibilities before the investment in a new power plant setup. Wind, small hydro, and solar photovoltaics have been considered the foremost efficient and feasible renewable sources. In 2021, the worldwide renewable power capacity had grown to 17%, despite supply chain disturbances and surges in prices. The renewable power market set a target of achieving a 95% increment in global power capacity by 2026. Hence, humankind should consider wind, hydro, and solar photovoltaics as the main energy sources, and there is a need to increase use of such sources. This paper highlights the latest developments, enormous technologies, and upcoming aspects of wind power, hydropower, and solar photovoltaics in India, as well as around the globe. The present status of renewable energy can motivate global power producers to spend their money on the installation of a new renewable power plant to obtain more economic benefits and give societal economic and environmental payback to humans. Full article

(This article belongs to the Special Issue Advances in Renewable Energy Systems)

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12 pages, 3104 KiB

Open AccessFeature PaperArticle

D-Limonene as a Promising Green Solvent for the Detachment of End-of-Life Photovoltaic Solar Panels under Sonication

by Dina Magdy Abdo, Teresa Mangialardi, Franco Medici and Luigi Piga

Processes 2023, 11(6), 1848; https://doi.org/10.3390/pr11061848 - 19 Jun 2023

Cited by 7 | Viewed by 1458

Abstract

Consumption of photovoltaic solar panels is expected to increase, so the growing amount of end-of-life (EOL) solar panels will require large spaces for their disposal, which at the moment costs around 200 euros/ton. Thus, a proper treatment technique to recover secondary materials from [...] Read more.

Consumption of photovoltaic solar panels is expected to increase, so the growing amount of end-of-life (EOL) solar panels will require large spaces for their disposal, which at the moment costs around 200 euros/ton. Thus, a proper treatment technique to recover secondary materials from this waste, which are mainly copper, aluminum, silicon, high-transmittance glass, and plastics, must be developed. The last three components are strongly attached to each other; hence, their detachment is necessary for recovery. To achieve this objective, a chemical route was chosen; in fact, solvent extraction is highly recommended, as it has a high separation efficiency. In this study, D-limonene as a bio-solvent was examined for detaching different components of solar panels from each other. A high efficiency for ethylene vinyl acetate (EVA) dissolution and components’ detachment under different conditions was achieved with the help of sonication power. The effects of sonication power, thermal pre-treatment, temperature, and contact time on detachment percentage were examined, and the best conditions (namely, no pre-treatment, medium sonication power of 450 W, temperature of 60 °C, and a contact time of 120 min) were found for total component detachment. Additionally, the recyclability of D-limonene was examined, and it was established that the solvent could carry out 100% component detachment for three cycles. Full article

(This article belongs to the Special Issue New Technologies and Processing of Photoelectric Functional Materials and Devices)

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13 pages, 2735 KiB

Open AccessArticle

Development of a Continuous Process Chain for Selective Recovery and Purification of Rare Metals

by Timo Dobler, Simon Buchheiser, Thomas Gaschler, Stefan Platzk, Harald Kruggel-Emden, Hermann Nirschl and Marco Gleiß

Processes 2023, 11(6), 1847; https://doi.org/10.3390/pr11061847 - 19 Jun 2023

Viewed by 986

Abstract

Solar cells, liquid crystal displays (LCDs) and light-emitting diodes (LEDs) have become more and more important in recent decades. Crucial components of such electronic devices include rare metals (e.g., indium and gallium), which are only available in limited quantities. In order to meet [...] Read more.

Solar cells, liquid crystal displays (LCDs) and light-emitting diodes (LEDs) have become more and more important in recent decades. Crucial components of such electronic devices include rare metals (e.g., indium and gallium), which are only available in limited quantities. In order to meet their rising demand in the coming years, recycling processes, especially those that enable selective recovery of the individual components, are steadily gaining in importance. One conceivable method is particle-loaded solvent extraction followed by mechanical processing. Therefore, we first investigated the possibility of recovering individual particle fractions from a multicomponent mixture on the basis of the surface properties. Both UV–Vis spectroscopy and small-angle X-ray scattering (WAXS) were used for evaluation. The conducted experiments showed, among other things, that the indium oxide content increased from 50% to 99% in a binary system and from 33% to 94% in a ternary compound. In addition, the purification of the separated particles was examined in detail. Using UV–Vis spectrometry, it was found that permeation washing of filter cakes is suitable for removing impurities and retrieving most of the solvent used. Based on the results of the conducted laboratory tests, we finally developed a concept for the continuous and selective recovery of rare metals. Full article

(This article belongs to the Section Environmental and Green Processes)

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11 pages, 276 KiB

Open AccessArticle

Scheduling Jobs with a Limited Waiting Time Constraint on a Hybrid Flowshop

by Sang-Oh Shim, BongJoo Jeong, June-Yong Bang and JeongMin Park

Processes 2023, 11(6), 1846; https://doi.org/10.3390/pr11061846 - 19 Jun 2023

Cited by 1 | Viewed by 867

Abstract

In this paper, we address a two-stage hybrid flowshop scheduling problem with identical parallel machines in each stage. The problem assumes that the queue (Q)-time for each job, which represents the waiting time to be processed in the current stage, must be limited [...] Read more.

In this paper, we address a two-stage hybrid flowshop scheduling problem with identical parallel machines in each stage. The problem assumes that the queue (Q)-time for each job, which represents the waiting time to be processed in the current stage, must be limited to a predetermined threshold due to quality concerns for the final product. This problem is motivated by one that occurs in the real field, especially in the diffusion workstation of a semiconductor fabrication. Our objective is to minimize the makespan of the jobs while considering product quality. To achieve this goal, we formulated mathematical programming, developed two dominance properties for this problem, and proposed three heuristics with the suggested dominance properties to solve the considered problem. We conducted simulation experiments to evaluate the performance of the proposed approaches using randomly generated problem instances that are created to closely resemble real production scenarios, and the results demonstrate their superiority over existing methods. Furthermore, we applied the proposed methods in a real-world setting within the semiconductor fabrication industry, where they have exhibited better performance compared to the dispatching rules commonly used in practical applications. These findings validate the effectiveness and applicability of our proposed methodologies in real-world scenarios. Full article

(This article belongs to the Special Issue Design, Modeling, Optimization and Control in Manufacturing Industries and Energy System)

14 pages, 2620 KiB

Open AccessArticle

Experimental Investigation and CFD Simulation of Cryogenic Condenser

by Seyedsajjad Jazayeri, Afham Pourahmad, Seyyed Amirreza Abdollahi, Amin. Hassanvand, Falah Alobaid and Babak Aghel

Processes 2023, 11(6), 1845; https://doi.org/10.3390/pr11061845 - 19 Jun 2023

Cited by 3 | Viewed by 1161

Abstract

In this research, experimental investigation and the computational fluid dynamic (CFD) simulation of a cryogenic condenser for oxygen liquefaction was carried out. The liquid nitrogen was used as a cooling fluid. In the simulation section, a three-dimensional model with a structured mesh with [...] Read more.

In this research, experimental investigation and the computational fluid dynamic (CFD) simulation of a cryogenic condenser for oxygen liquefaction was carried out. The liquid nitrogen was used as a cooling fluid. In the simulation section, a three-dimensional model with a structured mesh with high mesh quality for aspect ratio and skewness was considered. The multi-phase flow inside the condenser was studied numerically, using the volume of fluid (VOF) method. This work also examined the assessment of the vapor generation rate during the condensation of oxygen, based on the boiling heat transfer mechanism and the unique physical characteristics. The experiment was conducted to examine the simulation results. The effect of liquid nitrogen height on the oxygen mass flows was investigated using computational fluid dynamics (CFD). The average deviation of the CFD predictions from the available experimental oxygen mass flows was 17%. Full article

(This article belongs to the Special Issue Advances in Numerical Heat Transfer and Fluid Flow (2023))

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20 pages, 9687 KiB

Open AccessArticle

Research on the Access Planning of SOP and ESS in Distribution Network Based on SOCP-SSGA

by Yuxin Jia, Qiong Li, Xu Liao, Linjun Liu and Jian Wu

Processes 2023, 11(6), 1844; https://doi.org/10.3390/pr11061844 - 19 Jun 2023

Cited by 2 | Viewed by 1114

Abstract

This paper proposes a two-stage planning model for soft open point (SOP) and energy storage system (ESS) that considers the cost of faults in response to the current issue of SOP and ESS systems not considering the impact of SOP access on load [...] Read more.

This paper proposes a two-stage planning model for soft open point (SOP) and energy storage system (ESS) that considers the cost of faults in response to the current issue of SOP and ESS systems not considering the impact of SOP access on load transfer in the event of a fault in the distribution network. Firstly, considering the uncertainty of “PV-load”, typical scenarios of PV and load are constructed based on the clustering algorithm. Secondly, aiming at the economic performance of the distribution network and the capacity of PV access, a two-stage optimization model is established for the joint integration of SOP and ESS into the distribution network (normal and fault operation) under typical scenarios. The model is solved by using the second-order cone programming algorithm and steady-state genetic algorithm (SOCP-SSGA). Stage one involves planning for the integration capacity and location of SOP and ESS into the distribution network under each scenario within a period based on SOCP with the goal of minimizing economic costs. In stage two, the PV access capacity of the distribution network is optimized using SSGA with the goal of enhancing the PV accommodation capability. Finally, verification and analysis are conducted on an improved IEEE33 node system. The results show that when the system optimizes access to a group of SOP and ESS, the total economic cost is reduced by RMB 61,729 compared to random access, and the accessible PV capacity is increased by 0.5278 MW. Moreover, optimizing access to two sets of SOP and ESS can further reduce the total economic cost by RMB 107,048 compared to the optimized access group and increase accessible PV capacity by 1.5751 MW. Therefore, the proposed plan for SOP and ESS planning in this paper can significantly reduce the economic cost of distribution networks, enhance the absorption capacity of distributed photovoltaics, improve the voltage level of power grid operation, and, thereby, improve the economic and reliability of distribution network operation. Full article

(This article belongs to the Topic Power System Dynamics and Stability)

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20 pages, 7905 KiB

Open AccessArticle

Matrix Non-Structural Model and Its Application in Heat Exchanger Network without Stream Split

by Dinghao Li, Jingde Wang, Wei Sun and Nan Zhang

Processes 2023, 11(6), 1843; https://doi.org/10.3390/pr11061843 - 19 Jun 2023

Cited by 1 | Viewed by 624

Abstract

Heat integration by a heat exchanger network (HEN) is an important topic in chemical process system synthesis. From the perspective of optimization, the simultaneous synthesis of HEN belongs to a mixed-integer and nonlinear programming problem. Both the stage-wise superstructure (SWS) model and the [...] Read more.

Heat integration by a heat exchanger network (HEN) is an important topic in chemical process system synthesis. From the perspective of optimization, the simultaneous synthesis of HEN belongs to a mixed-integer and nonlinear programming problem. Both the stage-wise superstructure (SWS) model and the chessboard model are the most widely adopted and belong to structural models, in which a framework is assumed for stream matching, and the global optimal solution outside its feasible domain may be defined by the framework. A node-wise non-structural model (NW-NSM) is proposed to find more universal stream matching options, but it requires a mass of structural variables and extra multiple correction strategies. The aim of this paper is to develop a novel matrix non-structural model (M-NSM) for HEN without stream splits from the perspectives of global optimization methods and superstructure models. In the proposed M-NSM, the heat exchanger position order is quantized by matrix elements at each stream, and a HEN structure is initialized by the random generation of matrix elements. An approach for solving HEN problems based on a matrix real-coded genetic algorithm is employed in this model. The results show that M-NSM provides more flexibility to expand the search region for feasible solutions with higher efficiency than previous models. Full article

(This article belongs to the Special Issue Energy Integration and Optimization in the Chemical Process Industry)

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15 pages, 2887 KiB

Open AccessArticle

Immobilization of Pseudomonas fluorescens Lipase on Hollow Poly(o-phenylenediamine) Microspheres and Its Application in the Preparation of Citronellyl Acetate

by Jian Xiong, Qi Wang, Hanghang Xu and Wenyuan Sun

Processes 2023, 11(6), 1842; https://doi.org/10.3390/pr11061842 - 19 Jun 2023

Viewed by 728

Abstract

In order to address the challenges associated with free lipase in organic solvents, including aggregation, poor stability, and low catalytic efficiency, this study developed two types of poly(o-phenylenediamine) microspheres (solid and hollow) as supports for immobilizing lipase. The immobilization process utilized an adsorption [...] Read more.

In order to address the challenges associated with free lipase in organic solvents, including aggregation, poor stability, and low catalytic efficiency, this study developed two types of poly(o-phenylenediamine) microspheres (solid and hollow) as supports for immobilizing lipase. The immobilization process utilized an adsorption method, with the poly(o-phenylenediamine) hollow microspheres being identified as the optimal support in a 2:5 enzyme-to-support ratio. On this basis, the lipase was immobilized by the covalent binding method. The immobilization conditions consisted of treating the support with 2% glutaraldehyde and immobilization at 40 °C for 2 h in pH 7.0 buffer. The specific activity of the immobilized enzyme was 5.3 times higher than that of the free enzyme. Covalent-binding immobilized lipase was also used for the preparation of citronellyl acetate by transesterification reaction, and, in optimized reaction conditions where the amount of immobilized enzyme was 0.1 g/mL, the reaction temperature was 50 °C and the shaking speed was 200 r/min during the reaction. Under these conditions, the citronellyl acetate yields can exceed 99% after 2 h. Furthermore, the stability of the immobilized lipase was investigated, and the residual activity of the immobilized enzyme was 95% after seven repetitions, while that of the free enzyme was only 70%. After 56 days of storage at room temperature, the immobilized enzyme retained 60% of its original viability, while the free enzyme retained only 31%. Full article

(This article belongs to the Special Issue Enzyme Application in Sustainable Processes and Industrial Biocatalysis)

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27 pages, 20265 KiB

Open AccessArticle

Research on Path Planning and Tracking Control of Autonomous Vehicles Based on Improved RRT* and PSO-LQR

by Yong Zhang, Feng Gao and Fengkui Zhao

Processes 2023, 11(6), 1841; https://doi.org/10.3390/pr11061841 - 19 Jun 2023

Cited by 7 | Viewed by 2776

Abstract

Path planning and tracking control are essential parts of autonomous vehicle research. Regarding path planning, the Rapid Exploration Random Tree Star (RRT*) algorithm has attracted much attention due to its completeness. However, the algorithm still suffers from slow convergence and high randomness. Regarding [...] Read more.

Path planning and tracking control are essential parts of autonomous vehicle research. Regarding path planning, the Rapid Exploration Random Tree Star (RRT*) algorithm has attracted much attention due to its completeness. However, the algorithm still suffers from slow convergence and high randomness. Regarding path tracking, the Linear Quadratic Regulator (LQR) algorithm is widely used in various control applications due to its efficient stability and ease of implementation. However, the relatively empirical selection of its weight matrix can affect the control effect. This study suggests a path planning and tracking control framework for autonomous vehicles based on an upgraded RRT* and Particle Swarm Optimization Linear Quadratic Regulator (PSO-LQR) to address the abovementioned issues. Firstly, according to the driving characteristics of autonomous vehicles, a variable sampling area is used to limit the generation of random sampling points, significantly reducing the number of iterations. At the same time, an improved Artificial Potential Field (APF) method was introduced into the RRT* algorithm, which improved the convergence speed of the algorithm. Utilizing path pruning based on the maximum steering angle constraint of the vehicle and the cubic B-spline algorithm to achieve path optimization, a continuous curvature path that conforms to the precise tracking of the vehicle was obtained. In addition, optimizing the weight matrix of LQR using POS improved path-tracking accuracy. Finally, this article’s improved RRT* algorithm was simulated and compared with the RRT*, target bias RRT*, and P-RRT*. At the same time, on the Simulink–Carsim joint simulation platform, the PSO-LQR is used to track the planned path at different vehicle speeds. The results show that the improved RRT* algorithm optimizes the path search speed by 34.40% and the iteration number by 33.97%, respectively, and the generated paths are curvature continuous. The tracking accuracy of the PSO-LQR was improved by about 59% compared to LQR, and its stability was higher. The position error and heading error were controlled within 0.06 m and 0.05 rad, respectively, verifying the effectiveness and feasibility of the proposed path planning and tracking control framework. Full article

(This article belongs to the Special Issue Intelligent Techniques Used for Robotics)

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12 pages, 938 KiB

Open AccessReview

Use of Potential Immobilized Enzymes for the Modification of Liquid Foods in the Food Industry

by Ernestina Garcia-Quinto, Raquel Aranda-Cañada, Paz García-García and Gloria Fernández-Lorente

Processes 2023, 11(6), 1840; https://doi.org/10.3390/pr11061840 - 19 Jun 2023

Cited by 4 | Viewed by 2468

Abstract

Enzymes are complex proteins that carry out biochemical reactions. Apart from being necessary for life, they are used in numerous industrial processes, especially in the textile, pharmaceutical, food and chemical sectors. One of the longest-lived industries regarding the use of enzymes is the [...] Read more.

Enzymes are complex proteins that carry out biochemical reactions. Apart from being necessary for life, they are used in numerous industrial processes, especially in the textile, pharmaceutical, food and chemical sectors. One of the longest-lived industries regarding the use of enzymes is the food industry. Enzymes have always been used, mainly in their free form, to obtain new products and to improve the organoleptic qualities in different industries, such as in dairy, fruit and vegetables, and beverages. However, today, immobilized enzymes are the focus of attention in the liquid food industry, as they offer numerous advantages, such as stabilization and reuse, which enable cost reduction. Full article

(This article belongs to the Special Issue Enzyme Application in Sustainable Processes and Industrial Biocatalysis)

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16 pages, 6083 KiB

Open AccessFeature PaperArticle

Numerical Simulation of Wormhole Propagation with Foamed-Viscoelastic-Surfactant Acid in Carbonate Acidizing

by Lufeng Zhang, Haibo Wang, Fujian Zhou and Jianye Mou

Processes 2023, 11(6), 1839; https://doi.org/10.3390/pr11061839 - 19 Jun 2023

Cited by 2 | Viewed by 1249

Abstract

Successful matrix acidizing for extremely thick carbonate reservoirs with long horizontal well sections and strong heterogeneity requires efficient temporary plugging and diverting of acid fluid, ensuring acid fluid distribution to each production layer. Foamed-viscoelastic-surfactant (Foamed-VES) acid combines the benefits of both foam acid [...] Read more.

Successful matrix acidizing for extremely thick carbonate reservoirs with long horizontal well sections and strong heterogeneity requires efficient temporary plugging and diverting of acid fluid, ensuring acid fluid distribution to each production layer. Foamed-viscoelastic-surfactant (Foamed-VES) acid combines the benefits of both foam acid and viscoelastic surfactant (VES) acid, integrating foam plugging and viscous plugging. It can achieve uniform acid distribution in highly heterogeneous reservoirs. However, little research has been conducted on the wormhole propagation law of foamed-VES acid. To address this gap, this study established a mathematical model of foamed-VES acid wormhole propagation based on the dual-scale model. The model was coupled with a random porosity distribution generated with geological statistical software. The effects of different factors on foamed-VES acid etching were simulated. Numerical results show that foamed-VES acid can stimulate low-permeability reservoirs with a permeability differential of 20. Its inherent mechanism lies in the synergy of foam plugging and VES viscous plugging. This study enhances our understanding of the acid diversion mechanism of foamed-VES acid, providing a theoretical foundation for on-site acidizing treatment. Full article

(This article belongs to the Section Energy Systems)

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19 pages, 9487 KiB

Open AccessArticle

Improved Active Islanding Detection Technique with Different Current Injection Waveform

by Shaoru Zhang, Lijun Wang, Xiuju Du, Ruiye Zhang, Zhanping Huang, Shuchun Duan, Wenxiu Yang, Pingjun Wang and Jielu Zhang

Processes 2023, 11(6), 1838; https://doi.org/10.3390/pr11061838 - 18 Jun 2023

Cited by 3 | Viewed by 996

Abstract

The active frequency drift (AFD) method is an effective method to detect islanding in grid-connected photovoltaic systems. However, it has some inherent drawbacks, such as generating higher harmonics. In order to reduce the harmonics and non-detection zone (NDZ), various improved AFD methods have [...] Read more.

The active frequency drift (AFD) method is an effective method to detect islanding in grid-connected photovoltaic systems. However, it has some inherent drawbacks, such as generating higher harmonics. In order to reduce the harmonics and non-detection zone (NDZ), various improved AFD methods have been proposed, but they still suffer from high harmonics and reduced detection speed. To overcome these limitations, this paper proposes an innovative islanding detection technique based on AFD. Analysis reveals that the proposed method reduces harmonics by 68% compared to conventional AFD and has a larger chopping factor. Therefore, this technique offers several distinct advantages, including accelerated detection speed, reduced NDZ and harm caused by disturbances, and improved power quality. Furthermore, to verify the harmonic impact of this proposed islanding detection method, simulations and analyses are conducted using simulation software of Matlab/Simulink. An experimental prototype is set up in Laboratory. The simulation and experimental results demonstrate the superiority of the proposed method. Full article

(This article belongs to the Special Issue Design, Modeling, Optimization and Control in Manufacturing Industries and Energy System)

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18 pages, 3399 KiB

Open AccessArticle

Synthesis, Molecular Docking, Molecular Dynamics Studies, and In Vitro Biological Evaluation of New Biofunctional Ketoprofen Derivatives with Different N-Containing Heterocycles

by Stanimir Manolov, Dimitar Bojilov, Iliyan Ivanov, Gabriel Marc, Nadezhda Bataklieva, Smaranda Oniga, Ovidiu Oniga and Paraskev Nedialkov

Processes 2023, 11(6), 1837; https://doi.org/10.3390/pr11061837 - 17 Jun 2023

Cited by 2 | Viewed by 1403

Abstract

Herein, we report the synthesis of four new hybrid molecules between ketoprofen or 2-(3-benzoylphenyl)propanoic acid and N-containing heterocyclic compounds, such as piperidine, pyrrolidine, 1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroisoquinoline. The obtained hybrid compounds were fully characterized using ¹H- and ¹³C-NMR, UV-Vis, and HRMS [...] Read more.

Herein, we report the synthesis of four new hybrid molecules between ketoprofen or 2-(3-benzoylphenyl)propanoic acid and N-containing heterocyclic compounds, such as piperidine, pyrrolidine, 1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroisoquinoline. The obtained hybrid compounds were fully characterized using ¹H- and ¹³C-NMR, UV-Vis, and HRMS spectra. Detailed HRMS analysis is provided for all novel hybrid molecules. The compounds were assessed for their in vitro anti-inflammatory and antioxidant activity. The lipophilicity of the hybrids was determined, both theoretically (cLogP) and experimentally (R_M). The affinity of the compounds to the human serum albumin was assessed in silico by molecular docking study using two software, and the stability of the predicted complexes was evaluated by molecular dynamics study. All novel hybrids have shown very good HPSA activity, statistically close when compared to the reference—quercetin. The molecular docking confirmed the obtained in vitro results. Tetrahydroquinoline derivative 3c and tetrahydroisoquinoline derivative 3d have the highest affinity for albumin. They show stronger anti-inflammatory action than their predecessor, ketoprofen and the regularly used ibuprofen. Full article

(This article belongs to the Special Issue Synthesis, Application and Biological Evaluation of Chemical Organic Compounds)

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13 pages, 2672 KiB

Open AccessArticle

Development of Tea Tree Oil Based Nanoemulgel Loaded with Azithromycin for Enhancing the Antibacterial Activity

by Nasrin E. Khalifa, Marwa H. Abdallah, Hanaa A. Elghamry, Weam M. A. Khojali, El-Sayed Khafagy, Hemat El-Sayed El-Horany and Seham Shawky

Processes 2023, 11(6), 1836; https://doi.org/10.3390/pr11061836 - 17 Jun 2023

Cited by 1 | Viewed by 1230

Abstract

Azithromycin (AZ) is an azalide macrolide antibiotic that is frequently employed for treating bacterial skin infections. It suffers from limited oral bioavailability, which results from incomplete absorption or extensive first-pass metabolism. Therefore, preparing azithromycin formulations for topical administration is highly recommended to avoid [...] Read more.

Azithromycin (AZ) is an azalide macrolide antibiotic that is frequently employed for treating bacterial skin infections. It suffers from limited oral bioavailability, which results from incomplete absorption or extensive first-pass metabolism. Therefore, preparing azithromycin formulations for topical administration is highly recommended to avoid first-pass metabolism and to boost the concentration of the drug on the skin. The objective of our investigation was to formulate and evaluate the efficacy of AZ-loaded nanoemulgel as an antimicrobial drug. The physical appearance, spreadability, viscosity, particle size, in vitro drug release, ex vivo permeation investigations, and antimicrobial efficiency of the prepared formulations were evaluated. The prepared formulation loaded with AZ exhibited good physical quality. AZ-loaded nanoemulgel had a greater ex vivo drug permeation across rabbit skin than other formulations (AZ-loaded gel and AZ-loaded emulgel), revealing improved drug permeation and greater transdermal flux in addition to enhanced antibacterial efficacy (p < 0.05). Overall, our findings imply that tea-tree-oil-based nanoemulgel would be a promising delivery system for enhancing the antimicrobial efficiency of azithromycin. Full article

(This article belongs to the Special Issue Drug Carriers Production Processes for Innovative Human Applications)

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15 pages, 758 KiB

Open AccessFeature PaperArticle

Optimal Control of Technological Processes

by Anatoliy M. Tsirlin and Alexander I. Balunov

Processes 2023, 11(6), 1835; https://doi.org/10.3390/pr11061835 - 16 Jun 2023

Viewed by 828

Abstract

The paper formulates conditions under which the roots closest to the imaginary axis (critical roots) of the characteristic equation of a linearized system are real for the maximum possible degree of stability of the closed-loop control system of a technological process with pure [...] Read more.

The paper formulates conditions under which the roots closest to the imaginary axis (critical roots) of the characteristic equation of a linearized system are real for the maximum possible degree of stability of the closed-loop control system of a technological process with pure delay. For the parameters of the controllers corresponding to the maximum degree of stability, these roots are multiples. Their multiplicity order is one more than the number of coefficients in the transfer function of the controller. It is demonstrated that for a typical technological control object, these conditions are satisfied for all “serial” control laws. This allowed for obtaining analytical expressions for optimal settings and limiting degrees of stability as functions of object parameters for typical dynamic characteristics of technological processes. The paper considers the problem of robust stability for control systems with an object containing pure delay. It has been proven that in the maximum stability problem, the operations of maximizing over controller parameters and minimizing over the set of possible object parameters can be interchanged. Therefore, selecting robust settings amounts to determining the minimum of the maximum stability over the set of possible object parameter values. Controllers with such settings are suitable, without modification, for a whole class of technological processes. Full article

(This article belongs to the Special Issue Advances in Process Optimization and Control)

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14 pages, 2813 KiB

Open AccessArticle

Effects of Bio-Coal Briquette for Residential Combustion on Brown Carbon Emission Reduction

by Juan Qi and Jianjun Wu

Processes 2023, 11(6), 1834; https://doi.org/10.3390/pr11061834 - 16 Jun 2023

Viewed by 1102

Abstract

Biomass burning is an important source of brown carbon (BrC) which poses high-risk threats to human health and the environment. In this study, bio-coal briquette (coal mixed with biomass), a promising solid fuel for residential combustion, is proven to be a clean fuel [...] Read more.

Biomass burning is an important source of brown carbon (BrC) which poses high-risk threats to human health and the environment. In this study, bio-coal briquette (coal mixed with biomass), a promising solid fuel for residential combustion, is proven to be a clean fuel which can effectively reduce BrC emission. First of all, an orthogonal experiment with three factors and three levels on the physical property of bio-briquette was carried out to identify the optimal preparation conditions including the ratio of biomass to anthracite, particle size and molding pressure. Then a combustion experiment of the bio-coal briquetted was implemented in a simulated residential combustion system. BrC emission factors (EFs) were calculated based on the detected black carbon (BC) concentration by an aethalometer, and other optical characteristics for organic components of extract samplers, such as mass absorption efficiency (MAE) and absorption angstrom index (AAE), were also explored. Lastly, composition analysis of BrC by a gas chromatography (GC) tandem mass spectrometer (MS) and direct visible images by scanning electron microscopy (SEM) were investigated to provide more detail information on BrC EFs and property change. It was shown that bio-coal briquette had such low BrC EFs that 70–81% BrC was reduced in comparison with an interpolation value of 100% biomass and 100% coal. Furthermore, the composition of BrC from bio-coal briquette burning was different, which consisted of more substances with strong wavelength dependence. Consequently, although MAE declined by 60% at a 540 nm wavelength, the AAE value of bio-coal briquette only decreased slightly compared with interpolation values. To be more specific, tar balls, the main existing form of BrC, were distributed much more sparsely in the SEM image of bio-coal briquette. To sum up, a positive reduction effect on BrC was discovered in bio-coal briquette. It is evident that bio-coal briquette can serve as an alternative solid fuel for residential combustion, which is beneficial for both human health and the atmosphere. Full article

(This article belongs to the Section Environmental and Green Processes)

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22 pages, 16409 KiB

Open AccessArticle

Investigation on Water Invasion Mode and Remaining Oil Utilization Rules of Fractured-Vuggy Reservoirs: A Case Study of the Intersection Region of S99 Unit in Tahe Oilfield

by Hong Cheng, Feiyu Yuan, Shiliang Zhang, Lu Li, Xianping Luo and Bo Chen

Processes 2023, 11(6), 1833; https://doi.org/10.3390/pr11061833 - 16 Jun 2023

Cited by 2 | Viewed by 904

Abstract

Fractured-vuggy reservoirs are a new target in carbonate oil and gas exploration and development. Because of well-developed reservoir bodies, including fractures and caverns, bottom water invasion can be observed in oilfield development, with low utilization efficiency of crude oil in the reservoir. Accordingly, [...] Read more.

Fractured-vuggy reservoirs are a new target in carbonate oil and gas exploration and development. Because of well-developed reservoir bodies, including fractures and caverns, bottom water invasion can be observed in oilfield development, with low utilization efficiency of crude oil in the reservoir. Accordingly, this study focused on the intersection region of the S99 unit of the Tahe fractured-vuggy reservoirs. Based on seismic data, the reservoir bodies can be divided into three types—caverns, fractures, and broken solution pores. Using the same location condition assignment algorithm, four single-type models are fused into a multi-scale discrete three-dimensional geological model of fractured and cavernous reservoirs, and the corresponding fractured-vuggy reservoir model was established for numerical simulation. The single-well historical fitting precision exceeded 85%. Furthermore, the development can be divided into four stages—initial stage of production, peak production stage, liquid control and oil stabilization stage, and scale gas injection stable. Streamlining sweep analysis determined the utilization and distribution characteristics of the remaining oil in the reservoir. It can be concluded that structure, caverns, and fractures were the main controlling factors affecting the remaining oil distribution in the fractured-vuggy reservoir. The fluid exchange among single-well reserve zones was calculated using streamline-based quantitative sweep analysis and interwell flow quantitative analysis method. Through source-sink quantitative analysis, interwell flow relations were derived, and three water breakthrough modes were further concluded: violent flooding, slow ascending of water cut, and low cut or intermittent water production. Full article

(This article belongs to the Special Issue Multiphase Flow, and Efficient Development Methodology and Technology in Unconventional Reservoirs)

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