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Advanced Designs of Materials, Machines and Processes in a Circular Economy

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Manufacturing Processes and Systems".

Deadline for manuscript submissions: 20 October 2024 | Viewed by 28649

Special Issue Editors


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Guest Editor
Department of Machines and Technical Systems, Faculty of Mechanical Engineering, University of Science and Technology in Bydgoszcz, 85-796 Bydgoszcz, Poland
Interests: materials grindability; comminution; processing machines; sustainable development; eco-design; energy efficiency; environmental impact
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Guest Editor
Department of Machines and Technical Systems, Faculty of Mechanical Engineering, University of Science and Technology in Bydgoszcz, 85-796 Bydgoszcz, Poland
Interests: problems of understanding, describing and increasing the efficiency of complex technical systems occurring in the mechanical engineering, processing, ecological, chemical and energy industries

Special Issue Information

Dear Colleagues,

In light of the Sustainable Development Goals (17 Sustainable Development Goals—SDGs) adopted in the strategic documents of development of European Union countries, activities which lead to increasing the energy and ecological efficiency of technological processes, using materials and managing them rationally and economically, minimizing energy consumption, energy losses and environmental impact and decreasing the amount of production and post-consumer waste are of great importance. One of the concepts of material management in technological processes, from mining to post-consumer waste management, is the idea of a circular economy, which also takes into account the waste hierarchy resulting from the EU Waste Framework Directive. Materials and raw materials are used in almost every technological process both indirectly (machines that were previously made of materials and raw materials) and directly when they are processed or participate as a medium in production processes, and their circulation in the economy should be planned already at the design stage of products. It is important to be ecologically responsible in the design and assessment of the impact of materials and processes at each stage of the life cycle of products (from production, through use to end-of-life management) in order to maximize the environmental harmlessness and energy efficiency of processes and the use of materials while minimizing waste. The mutual relations between the properties of materials (especially processing characteristics) and the design features of machines and process parameters should be taken into account when implementing the concept of a circular economy, because they significantly affect processing efficiency, resource consumption, and the environmental impact of products and processes, as well as the generation of waste and the formation of factory rejects in production.

The purpose of this Special Issue is to disseminate valuable research studies identifying recent problems of the circular economy from the point of view of processing and management of materials, processes and design of processing machines, as well as introducing practical and methodological innovations to improve the efficiency, quality and harmlessness in the life cycle of products, materials and processes, including modeling and research on the properties of materials, machines and processes and their interrelations.

The scope of the Special Issue includes the following topics:

  • Advanced eco-friendly methods of material processing;
  • Modeling and testing the processing properties of materials;
  • Research and modeling of machines and processing processes;
  • Research, evaluation and analysis of the quality, effectiveness and harmlessness of products and processes in the life cycle;
  • Circular economy in the life cycle of products;
  • Analysis and assessment of environmental impacts of materials, machines, processes;
  • Eco-design, design for recycling/circular economy;
  • Recycling, processing, use and management of waste;
  • Identification of relationships between materials, machines and processes.

Dr. Weronika Kruszelnicka
Prof. Dr. Andrzej Tomporowski
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • circular economy
  • waste management
  • waste reduction
  • recycling
  • relations between materials, machines and processes
  • eco-design
  • process efficiency and quality
  • environmental performance of materials, processes, machines and systems

Published Papers (14 papers)

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Research

15 pages, 6351 KiB  
Article
Exploration of Textile–Silicone Composites and Materials for Personal Impact-Resistant Protection
by Mei-Ki Chan, Pui-Ling Li, Kit-Lun Yick, Joanne Yip and Sun-Pui Ng
Materials 2024, 17(6), 1439; https://doi.org/10.3390/ma17061439 - 21 Mar 2024
Viewed by 642
Abstract
Conventional cushioning materials such as silicone sheets which have been recommended for resisting impact generally cause discomfort to the wearer from heat and perspiration. With the increasing need for personal protective equipment, textile–silicone composite structures are proposed in this study to reduce acute [...] Read more.
Conventional cushioning materials such as silicone sheets which have been recommended for resisting impact generally cause discomfort to the wearer from heat and perspiration. With the increasing need for personal protective equipment, textile–silicone composite structures are proposed in this study to reduce acute impact and moisture while enhancing thermal comfort. The influence of the composite structure and thickness on the mechanical and thermal properties of textile–silicone materials are systematically investigated. The results show that an additional knitted powernet fabric as a composite material can significantly improve the tensile properties of silicone rubber by up to 315%. However, only a slight improvement is found in the thermal conductivity (up to 16%), compression elasticity (up to 18%) and force reduction performance (up to 3.6%). As compared to inlaid spacer fabric, which has also been used for cushioning and preserving thermal comfort, the textile–silicone composites have higher tensile and compression elasticity, exhibit force reduction with the largest difference of 43% and are more thermally conductive, with increases more than 38%. The findings of this study introduced a cost-effective new silicone–textile composite for optimal impact protection and wear comfort for protective applications. Full article
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15 pages, 3696 KiB  
Article
Using the LCA Method to Develop the Production of Pigment for Processing Plastics
by Patrycja Bałdowska-Witos, Andrzej Tomporowski and Marek Bieliński
Materials 2023, 16(16), 5524; https://doi.org/10.3390/ma16165524 - 8 Aug 2023
Viewed by 899
Abstract
In recent years, the chemical industry has been developing more and more dynamically, which results in the introduction of many new chemical substances to the market. However, some of them do not meet the accepted standards and may be toxic to humans and [...] Read more.
In recent years, the chemical industry has been developing more and more dynamically, which results in the introduction of many new chemical substances to the market. However, some of them do not meet the accepted standards and may be toxic to humans and the environment. This problem largely concerns polymer materials, which are currently widely used in many areas of the economy. This is indirectly related to the coloring of these materials during processing. Therefore, it became necessary to introduce modern research procedures that enable the quantitative and qualitative determination of the impact of coloring agents in the processing of plastics, in order to include their negative impact on humans and the natural environment. The LCA methodology was used in this work, with ReCiPe 2016 used as the test method. Among the analyzed technological operations, the highest negative impact on the environment was characterized by the process related to heating the tested material (2.08 × 10−1 Pt). Among the materials, polyethylene terephthalate was distinguished by the greatest harmful effect on human health (2.91 × 10−1 Pt) and the quality (2.35 × 10−2 Pt) of the environment. The use of recycling processes would reduce the negative impact on human health (about −3.71 Pt), the ecosystem (about −0.14 Pt), and resources (about −0.27 Pt). Full article
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19 pages, 560 KiB  
Article
Environmentally Oriented Analysis of Benefits and Expenditures in the Life Cycle of a Wind Power Plant
by Łukasz Sobaszek, Izabela Piasecka, Józef Flizikowski, Andrzej Tomporowski, Edgar Sokolovskij and Patrycja Bałdowska-Witos
Materials 2023, 16(2), 538; https://doi.org/10.3390/ma16020538 - 5 Jan 2023
Cited by 3 | Viewed by 1301
Abstract
The motivation for this study was the need to extend and supplement the previously conducted research on technical objects in the renewable energy sector with analyses of the environmental impact of the production, operation and post-operational development stages of the wind power plant. [...] Read more.
The motivation for this study was the need to extend and supplement the previously conducted research on technical objects in the renewable energy sector with analyses of the environmental impact of the production, operation and post-operational development stages of the wind power plant. The main purpose of the work was to investigate, analyze and assess the ecological effects of a real facility, which is a 2 MW Vestas V90/105 m wind farm, throughout its life cycle. The life cycle assessment analysis of the 2 MW wind power plant was performed using Impact 2002+ modeling. The results are presented for all impact levels and categories. The production stage was characterized by the highest total level of harmful effect. The use of recycling reduces the negative impacts of the life cycle by 6.5%. The investigated technical facility has the greatest negative impact during the production stage, especially in the area of depletion of fossil resources and human health. Full article
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25 pages, 2792 KiB  
Article
Assessment of the Life Cycle of a Wind and Photovoltaic Power Plant in the Context of Sustainable Development of Energy Systems
by Katarzyna Piotrowska, Izabela Piasecka, Zbigniew Kłos, Andrzej Marczuk and Robert Kasner
Materials 2022, 15(21), 7778; https://doi.org/10.3390/ma15217778 - 4 Nov 2022
Cited by 9 | Viewed by 2165
Abstract
The conversion of kinetic energy from wind and solar radiation into electricity during the operation of wind and photovoltaic power plants causes practically no emissions of chemical compounds that are harmful to the environment. However, the production of their materials and components, as [...] Read more.
The conversion of kinetic energy from wind and solar radiation into electricity during the operation of wind and photovoltaic power plants causes practically no emissions of chemical compounds that are harmful to the environment. However, the production of their materials and components, as well as their post-use management after the end of their operation, is highly consumptive of energy and materials. For this reason, this article aims to assess the life cycle of a wind and photovoltaic power plant in the context of the sustainable development of energy systems. The objects of the research were two actual technical facilities—a 2 MW wind power plant and a 2 MW photovoltaic power plant, both located in Poland. The analysis of their life cycle was carried out on the basis of the LCA (life-cycle assessment) method, using the ReCiPe 2016 calculation procedure. The impact of the examined renewable energy systems was assessed under 22 impact categories and 3 areas of influence (i.e., human health, ecosystems, and resources), and an analysis was conducted for the results obtained as part of three compartments (i.e., air, water, and soil). The life cycle of the wind power plant was distinguished by a higher total potential negative environmental impact compared to the life cycle of the photovoltaic power plant. The highest levels of potential harmful impacts on the environment in both life cycles were recorded for areas of influence associated with negative impacts on human health. Emissions to the atmosphere accounted for over 90% of all emissions in the lifetimes of both the wind and the photovoltaic power plants. On the basis of the obtained results, guidelines were proposed for pro-ecological changes in the life cycle of materials and elements of the considered technical facilities for renewable energy sources, aimed at better implementation of the main assumptions of contemporary sustainable development (especially in the field of environmental protection). Full article
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22 pages, 10861 KiB  
Article
Energy-Dependent Particle Size Distribution Models for Multi-Disc Mill
by Weronika Kruszelnicka, Marek Opielak, Kingsly Ambrose, Saugirdas Pukalskas, Andrzej Tomporowski and Patrycja Walichnowska
Materials 2022, 15(17), 6067; https://doi.org/10.3390/ma15176067 - 1 Sep 2022
Cited by 4 | Viewed by 1445
Abstract
Comminution is important in the processing of biological materials, such as cereal grains, wood biomass, and food waste. The most popular biomaterial grinders are hammer and roller mills. However, the grinders with great potential in the processing of biomass are mills that use [...] Read more.
Comminution is important in the processing of biological materials, such as cereal grains, wood biomass, and food waste. The most popular biomaterial grinders are hammer and roller mills. However, the grinders with great potential in the processing of biomass are mills that use cutting, e.g., disc mills. When it comes to single-disc and multi-disc grinders, there are not many studies describing the relationships between energy, motion, material, and processing or describing the effect of grinding, meaning the size distribution of a product. The relationship between the energy and size reduction ratio of disc-type grinder designs has also not been sufficiently explored. The purpose of this paper was to develop models for the particle size distribution of the ground product in multi-disc mills depending on the variable process parameters, i.e., disc rotational velocity and, consequently, power consumption, and the relationship between the grinding energy and the shape of graining curves, which would help predict the product size reduction ratio for these machines. The experiment was performed using a five-disc mill, assuming the angular velocity of the grinder discs was variable. Power consumption, product particle size, and specific comminution energy were recorded during the tests. The Rosin–Rammler–Sperling–Bennet (RRSB) distribution curves were established for the ground samples, and the relationships between distribution coefficients and the average angular velocity of grinder discs, power consumption, and specific comminution energy were determined. The tests showed that the specific comminution energy increases as the size reduction ratio increases. It was also demonstrated that the RRSB distribution coefficients could be represented by the functions of angular velocities, power consumption, and specific comminution energy. The developed models will be a source of information for numerical modelling of comminution processes. Full article
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22 pages, 5734 KiB  
Article
Microstructure and Wear Characterization of the Fe-Mo-B-C—Based Hardfacing Alloys Deposited by Flux-Cored Arc Welding
by Michał Bembenek, Pavlo Prysyazhnyuk, Thaer Shihab, Ryszard Machnik, Olexandr Ivanov and Liubomyr Ropyak
Materials 2022, 15(14), 5074; https://doi.org/10.3390/ma15145074 - 21 Jul 2022
Cited by 37 | Viewed by 2994
Abstract
An analysis of common reinforcement methods of machine parts and theoretical bases for the selection of their chemical composition were carried out. Prospects for using flux-cored arc welding (FCAW) to restore and increase the wear resistance of machine parts in industries such as [...] Read more.
An analysis of common reinforcement methods of machine parts and theoretical bases for the selection of their chemical composition were carried out. Prospects for using flux-cored arc welding (FCAW) to restore and increase the wear resistance of machine parts in industries such as metallurgy, agricultural, wood processing, and oil industry were presented. It is noted that conventional series electrodes made of tungsten carbide are expensive, which limits their widespread use in some industries. The scope of this work includes the development of the chemical composition of tungsten-free hardfacing alloys based on the Fe-Mo-B-C system and hardfacing technology and the investigation of the microstructure and the mechanical properties of the developed hardfacing alloys. The composition of the hardfacing alloys was developed by extending the Fe-Mo-B-C system with Ti and Mn. The determination of wear resistance under abrasion and impact-abrasion wear test conditions and the hardness measurement by means of indentation and SEM analysis of the microstructures was completed. The results obtained show that the use of pure metal powders as starting components for electrodes based on the Fe-Mo-B-C system leads to the formation of a wear-resistant phase Fe(Mo,B)2 during FCAW. The addition of Ti and Mn results in a significant increase in abrasion and impact-abrasion wear resistance by 1.2 and 1.3 times, respectively. Full article
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16 pages, 1976 KiB  
Article
Ways to Improve the Efficiency of Devices for Freezing of Small Products
by Oleg Bazaluk, Nikolai Struchaiev, Serhii Halko, Oleksandr Miroshnyk, Larysa Bondarenko, Oleksandr Karaiev and Vitalii Nitsenko
Materials 2022, 15(7), 2412; https://doi.org/10.3390/ma15072412 - 25 Mar 2022
Cited by 6 | Viewed by 1765
Abstract
It has been established that one of the main problems in the technology of the production of loose food products is the sticking of vegetables or fruits into one block. It has been proven that one of the steps to solve this problem [...] Read more.
It has been established that one of the main problems in the technology of the production of loose food products is the sticking of vegetables or fruits into one block. It has been proven that one of the steps to solve this problem is the use of berries, fruits, or vegetables during freezing in the form of a fluidized bed in air. However, a significant part of the energy is spent precisely when creating a fluidized bed with the help of fans. By improving the separation efficiency of small products in the freezing process, it would be possible to significantly reduce the energy costs of freezing worldwide. The purpose of this work was to determine ways to increase the efficiency of devices for freezing small products. The goal was achieved through the use of a modified method for studying energy costs, taking into account energy costs for fluidization and mechanical shaking. For comparison, two options for the efficient separation of small products during freezing were considered. Namely the separation of small products in the process of freezing with the help of fluidization, and with the help of mechanical shaking. Comparison of these variants showed that it was advisable to separate small products during freezing by mechanical shaking. It was established that their energy parameters, as well as fractional properties, are significantly different. The product temperature was determined for the case of a constant temperature of the cooling air and equipment elements. The results obtained confirmed the possibility of achieving significant energy savings of 1.5–3.5 times by using the mechanized device we proposed for freezing fruits and vegetables. The main result of this paper is the proposed method, or algorithm, for calculating energy costs for fluidization and mechanical shaking, which could be used in the design of devices for the freezing of small products; as well as the obtained data confirming the correspondence of the theoretical calculations to reality. The novelty of the research consists in presenting a model or algorithm for calculating the energy costs for fluidization and mechanical shaking. The importance of the results of the work lies in the possibility of using this technique to assess the energy effectiveness of devices for the freezing of small products. Full article
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13 pages, 4890 KiB  
Article
Finite Element Analysis of Silver Nanorods, Spheres, Ellipsoids and Core–Shell Structures for Hyperthermia Treatment of Cancer
by Muhammad Usama Daud, Ghulam Abbas, Muhammad Afzaal, Muhammad Yasin Naz, Nazma Goher Fatima, Abdul Ghuffar, Muhammad Irfan, Mater H. Mahnashi, Stanislaw Legutko, Jana Petrů, Jiří Kratochvíl and Usama Muhammad Niazi
Materials 2022, 15(5), 1786; https://doi.org/10.3390/ma15051786 - 26 Feb 2022
Cited by 4 | Viewed by 2619
Abstract
The finite element analysis technique was used to investigate the suitability of silver nanorods, spheres, ellipsoids and core–shell structures for the hyperthermia treatment of cancer. The temperature of the silver nanostructures was raised from 42 to 46 °C, in order to kill the [...] Read more.
The finite element analysis technique was used to investigate the suitability of silver nanorods, spheres, ellipsoids and core–shell structures for the hyperthermia treatment of cancer. The temperature of the silver nanostructures was raised from 42 to 46 °C, in order to kill the cancerous cells. The time taken by the nanostructures to attain this temperature, with external source heating, was also estimated. The heat transfer module in COMSOL Multiphysics was used for the finite element analysis of hyperthermia, based on silver nanostructures. The thermal response of different shapes of silver nanostructures was evaluated by placing them inside the spherical domain of the tumor tissue. The proposed geometries were heated at different time intervals. Optimization of the geometries was performed to achieve the best treatment temperature. It was observed that silver nanorods quickly attain the desired temperature, as compared to other shapes. The silver nanorods achieved the highest temperature of 44.3 °C among all the analyzed geometries. Moreover, the central volume, used to identify the thermal response, was the maximum for the silver nano-ellipsoids. Thermal equilibrium in the treatment region was attained after 0.5 μs of heating, which made these structures suitable for hyperthermia treatment. Full article
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15 pages, 5078 KiB  
Article
Gold Nanorods for Doxorubicin Delivery: Numerical Analysis of Electric Field Enhancement, Optical Properties and Drug Loading/Releasing Efficiency
by Muhammad Qamar, Ghulam Abbas, Muhammad Afzaal, Muhammad Y. Naz, Abdul Ghuffar, Muhammad Irfan, Stanislaw Legutko, Jerzy Jozwik, Magdalena Zawada-Michalowska, Abdulnour Ali Jazem Ghanim, Saifur Rahman, Usama M. Niazi, Mohammed Jalalah, Fahad Salem Alkahtani, Mohammad K. A. Khan and Ewelina Kosicka
Materials 2022, 15(5), 1764; https://doi.org/10.3390/ma15051764 - 26 Feb 2022
Cited by 11 | Viewed by 2296
Abstract
The optical properties and electric field enhancement of gold nanorods for different cases were investigated in this study. The numerical analysis was carried out to understand the functionality and working of gold nanorods, while the experimental portion of the work was focused on [...] Read more.
The optical properties and electric field enhancement of gold nanorods for different cases were investigated in this study. The numerical analysis was carried out to understand the functionality and working of gold nanorods, while the experimental portion of the work was focused on the efficiency of gold nanorods for targeted drug delivery. COMSOL Multiphysics was used for numerical analysis. The theoretical results suggest the use of gold nanorods (AuNRs) for anticancer applications. The resonance peaks for gold nanorods of 10 nm diameter were observed at 560 nm. The resonance peaks shifted towards longer wavelengths with an increase in nanorod size. The resonance peaks showed a shift of 140 nm with a change in nanorod length from 25 to 45 nm. On the experimental side, 22 nm, 35 nm and 47 nm long gold nanorods were produced using the seed-mediated growth method. The surface morphology of the nanorods, as well as their optical characteristics, were characterized. Later, gold nanorods were applied to the targeted delivery of the doxorubicin drug. Gold nanorods showed better efficiency for doxorubicin drug loading time, release time, loading temperature, and release temperature. These results reveal that AuNRs@DA possess good ability to load and deliver the drug directly to the tumorous cells since these cells show high temperature and acidity. Full article
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13 pages, 4903 KiB  
Article
Preparation and Characterization of Glass-Ceramic Foam from Clay-Rich Waste Diatomaceous Earth
by Martin Sedlačík, Martin Nguyen, Tomáš Opravil and Radomír Sokolář
Materials 2022, 15(4), 1384; https://doi.org/10.3390/ma15041384 - 13 Feb 2022
Cited by 6 | Viewed by 2251
Abstract
In this study, the potential use of waste diatomaceous earth from the production of diatomaceous earth for filtration purposes, as an alternative raw material for foam glass production, was explored. The chemical and mineralogical composition and the high temperature behavior of waste diatomite [...] Read more.
In this study, the potential use of waste diatomaceous earth from the production of diatomaceous earth for filtration purposes, as an alternative raw material for foam glass production, was explored. The chemical and mineralogical composition and the high temperature behavior of waste diatomite were studied to assess its suitability for foam glass production. Glass-ceramic foams were prepared using NaOH solution as a foaming agent, via a hydrate mechanism. The influence of different pretreatments and firing temperatures on the foam’s structure, bulk density and compressive strength was investigated. High temperature behavior was studied using TG/DTA analysis and high temperature microscopy. Phase composition was studied using X-ray diffraction analysis. Glass-ceramic foam samples of a high porosity comparable to conventional foam glass products were fabricated. The pretreatment temperature, foaming temperature and sintering holding time were found to have a significant influence on foam properties. With increased pretreatment temperature, pyrogenic carbon from the thermal decomposition of organic matter contained in the raw material acted as an additional foaming agent and remained partially unoxidized in prepared foams. The bulk densities of prepared samples ranged from 150 kg/m3 to 510 kg/m3 and their compressive strengths were between 140 and 1270 kPa. Full article
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22 pages, 6246 KiB  
Article
Synthesis and Characterization of Manganese-Modified Black TiO2 Nanoparticles and Their Performance Evaluation for the Photodegradation of Phenolic Compounds from Wastewater
by Muhammad Irfan, Rab Nawaz, Javed Akbar Khan, Habib Ullah, Tahir Haneef, Stanislaw Legutko, Saifur Rahman, Jerzy Józwik, Mabkhoot A. Alsaiari, Mohammad Kamal Asif Khan, Salim Nasar Faraj Mursal, Fahad Salem AlKahtani, Omar Alshorman and Abdulnour Ali Jazem Ghanim
Materials 2021, 14(23), 7422; https://doi.org/10.3390/ma14237422 - 3 Dec 2021
Cited by 11 | Viewed by 2335
Abstract
The release of phenolic-contaminated treated palm oil mill effluent (TPOME) poses a severe threat to human and environmental health. In this work, manganese-modified black TiO2 (Mn-B-TiO2) was produced for the photodegradation of high concentrations of total phenolic compounds from TPOME. [...] Read more.
The release of phenolic-contaminated treated palm oil mill effluent (TPOME) poses a severe threat to human and environmental health. In this work, manganese-modified black TiO2 (Mn-B-TiO2) was produced for the photodegradation of high concentrations of total phenolic compounds from TPOME. A modified glycerol-assisted technique was used to synthesize visible-light-sensitive black TiO2 nanoparticles (NPs), which were then calcined at 300 °C for 60 min for conversion to anatase crystalline phase. The black TiO2 was further modified with manganese by utilizing a wet impregnation technique. Visible light absorption, charge carrier separation, and electron–hole pair recombination suppression were all improved when the band structure of TiO2 was tuned by producing Ti3+ defect states. As a result of the enhanced optical and electrical characteristics of black TiO2 NPs, phenolic compounds were removed from TPOME at a rate of 48.17%, which is 2.6 times higher than P25 (18%). When Mn was added to black TiO2 NPs, the Ti ion in the TiO2 lattice was replaced by Mn, causing a large redshift of the optical absorption edges and enhanced photodegradation of phenolic compounds from TPOME. The photodegradation efficiency of phenolic compounds by Mn-B-TiO2 improved to 60.12% from 48.17% at 0.3 wt% Mn doping concentration. The removal efficiency of phenolic compounds from TPOME diminished when Mn doping exceeded the optimum threshold (0.3 wt%). According to the findings, Mn-modified black TiO2 NPs are the most effective, as they combine the advantages of both black TiO2 and Mn doping. Full article
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23 pages, 6968 KiB  
Article
A Fuzzy Logic Model for the Analysis of Ultrasonic Vibration Assisted Turning and Conventional Turning of Ti-Based Alloy
by Riaz Muhammad
Materials 2021, 14(21), 6572; https://doi.org/10.3390/ma14216572 - 1 Nov 2021
Cited by 11 | Viewed by 1726
Abstract
Titanium and its alloys are largely used in various applications due its prominent mechanical properties. However, the machining of titanium alloys is associated with assured challenges, including high-strength, low thermal conductivity, and long chips produced in conventional machining processes, which result in its [...] Read more.
Titanium and its alloys are largely used in various applications due its prominent mechanical properties. However, the machining of titanium alloys is associated with assured challenges, including high-strength, low thermal conductivity, and long chips produced in conventional machining processes, which result in its poor machinability. Advanced and new machining techniques have been used to improve the machinability of these alloys. Ultrasonic vibration assisted turning (UVAT) is one of these progressive machining techniques, where vibrations are imposed on the cutting insert, and this process has shown considerable improvement in terms of the machinability of hard-to-cut alloys. Therefore, selecting the right cutting parameters for conventional and assisted machining processes is critical for obtaining the anticipated dimensional accuracy and improved surface roughness of Ti-alloys. Hence, fuzzy-based algorithms were developed for the ultrasonic vibration assisted turning (UVAT) and conventional turning (CT) of the Ti-6Al7Zr3Nb4Mo0.9Nd alloy to predict the maximum process zone temperature, cutting forces, surface roughness, shear angle, and chip compression ratio for the selected range of input parameters (speed and depth-of-cut). The fuzzy-measured values were found to be in good agreement with the experimental values, indicating that the created models can be utilized to accurately predict the studied machining output parameters in CT and UVAT processes. The studied alloy resulted in discontinued chips in both the CT and UVAT processes. The achieved results also demonstrated a significant decline in the cutting forces and improvements in the surface quality in the UVAT process. Furthermore, the chip discontinuity is enhanced by the UVAT process due to the higher process zone temperature and the micro-impact imposed by the cutting tool on the workpiece. Full article
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19 pages, 951 KiB  
Article
The Comparative Assessment of Effects on the Power System and Environment of Selected Electric Transport Means in Poland
by Katarzyna Markowska, Józef Flizikowski, Kazimierz Bieliński, Andrzej Tomporowski, Weronika Kruszelnicka, Robert Kasner, Patrycja Bałdowska-Witos and Łukasz Mazur
Materials 2021, 14(16), 4556; https://doi.org/10.3390/ma14164556 - 13 Aug 2021
Cited by 5 | Viewed by 2393
Abstract
Currently, electric vehicles are a rapidly growing alternative to those with combustion engines and can contribute to reduction of CO2 emissions in the transport sector, especially when the energy to power electric motors is predominantly derived from renewable sources. Until now, the [...] Read more.
Currently, electric vehicles are a rapidly growing alternative to those with combustion engines and can contribute to reduction of CO2 emissions in the transport sector, especially when the energy to power electric motors is predominantly derived from renewable sources. Until now, the comparison of environmental impact and influence of electric transport means on the power systems was not fully addressed in the case of Poland. The purpose of the study is to describe, analyse and assess electric vehicles (EV) operation against performance indicators in Poland, especially the influence of electric transport means (ETM) (electric cars, trams, trolley buses and buses) on power system and environment. The influence on the power system was investigated for the Polish National Powers system using the simulation of different scenarios of loads generated by EV charging. The energy demand of the National Power System and daily load variability indices were determined. Based on the data of ETM powers consumption and emissions of energy production, the emissions of harmful gases per one km and per one person were calculated, as well as the financial outlays for energy necessary to drive 1 km per 1 passenger. To assess and compare the environmental impact of the selected ETM life cycle, the life cycle assessment method was used. The results of environmental impacts were determined for selected assessment methods: CML 2 and IPCC 2013 GWP 100. The functional unit in this study is one selected ETM with a service life of 100,000 km. Comparison of trams, trolley buses, buses and electric passenger cars indicates that most beneficial are electric buses which do not need rails or overhead lines, thus investment costs are lower. Full article
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24 pages, 9297 KiB  
Article
Analysis of the Erosivity of High-Pressure Pulsating Water Jets Produced in the Self-Excited Drill Head
by Monika Szada-Borzyszkowska, Wojciech Kacalak, Dariusz Lipiński and Błażej Bałasz
Materials 2021, 14(15), 4165; https://doi.org/10.3390/ma14154165 - 27 Jul 2021
Cited by 5 | Viewed by 1852
Abstract
The dynamic impact of a water jet with a periodically changing structure can be used in various industries. The paper presents a design solution for a self-excited pulse head. This head can be used in mining for drilling holes and breaking rocks. The [...] Read more.
The dynamic impact of a water jet with a periodically changing structure can be used in various industries. The paper presents a design solution for a self-excited pulse head. This head can be used in mining for drilling holes and breaking rocks. The design of the head was developed based on computer simulations, which made it possible to learn the mechanism of impulse shaping inside the head. Tests of the water jet produced in the self-excited pulsation head showed the occurrence of periodic changes in its internal structure and pulsation frequency. A significant increase in the dynamic stream pressures was demonstrated for the head working in the water environment compared to the head working in the air environment For example, for nominal medium and highest pressures, this increase is up to 82%, while for the lowest pressures (10 MPa), the pressure force values increase by 46%. It was found that an increase in the nominal water pressure causes a decrease in the frequency of hydrodynamic pulses in the head operating in both the water and air environment. Full article
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Tentative Title: 

Microstructure And Wear Characterization of the Fe-Mo-Ti-B-C – based hardfacing alloy deposited by flux-cored arc welding

Authors: 

Michał Bembenek 1*, Pavlo Prysyazhnyuk 2, Thaer Shihab 3,4, Olexandr Ivanov 5, Ryszard Machnik 6 and Liubomyr Ropyak 7

1    Department of Manufacturing Systems, Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, 30-059 Kraków, Poland

2    Department of Welding, Ivano-Frankivsk National Technical University of Oil and Gas, Ivano-Frankivsk 076019, Ukraine

3    Medical Instruments Techniques Engineering Department, Technical College of Engineering, Al-Bayan University, Baghdad/Jadriya 10070, Iraq

4    Department of Welding, Ivano-Frankivsk National Technical University of Oil and Gas, Ivano-Frankivsk 076019, Ukraine

5    Separate Structural Subdivision «Professional College of Electronic Devices Ivano-Frankivsk National Technical University of Oil and Gas», Ivano-Frankivsk 076006, Ukraine

6    Department of Manufacturing Systems, Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, 30-059 Kraków, Poland

7    Department of Computerized Engineering, Ivano-Frankivsk National Technical University of Oil and Gas, Ivano-Frankivsk 076019, Ukraine

 

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