G. Petriashvili, K. Chubinidze, T. Tatrishvili, E. Kalandia, Ana Petriashvili, M. Chubinidze
Diabetes mellitus is a chronic metabolic disease characterized by elevated blood glucose levels and has become a global challenge. Currently, the widespread and regular treatment of diabetes mellitus involves the administration of insulin. However, insulin is no longer considered the first choice for type 2 diabetes, and an expanding range of new treatment modalities are emerging as noninsulin-based medications that are promising alternatives to regulate blood glucose levels. In this regard, controlling the glucose level in blood by external stimuli, such as light, offers a new route to governing the blood glucose concentration with the required dose and at the appropriate time. Here, we report on a light-stimulated glucose-lowering method based on spiropyran-merocyanine photoisomerization. We show that upon exposure to violet light (405 nm), the closed isoform of spiropyran molecules inside liquid crystal microspheres transforms into the open merocyanine isoform, which in turn stimulates merocyanine to translocate through the interface of the liquid crystal/dextrose emulsion. Merocyanine readily interacts with glucose molecules and causes a lowering of the emulsion’s total glucose concentration by 20 %.
{"title":"LIGHT-STIMULATED LOWERING OF GLUCOSE CONCENTRATION IN A DEXTROSE SOLUTION MEDIATED BY MEROCYANINE MOLECULES","authors":"G. Petriashvili, K. Chubinidze, T. Tatrishvili, E. Kalandia, Ana Petriashvili, M. Chubinidze","doi":"10.17222/mit.2022.639","DOIUrl":"https://doi.org/10.17222/mit.2022.639","url":null,"abstract":"Diabetes mellitus is a chronic metabolic disease characterized by elevated blood glucose levels and has become a global challenge. Currently, the widespread and regular treatment of diabetes mellitus involves the administration of insulin. However, insulin is no longer considered the first choice for type 2 diabetes, and an expanding range of new treatment modalities are emerging as noninsulin-based medications that are promising alternatives to regulate blood glucose levels. In this regard, controlling the glucose level in blood by external stimuli, such as light, offers a new route to governing the blood glucose concentration with the required dose and at the appropriate time. Here, we report on a light-stimulated glucose-lowering method based on spiropyran-merocyanine photoisomerization. We show that upon exposure to violet light (405 nm), the closed isoform of spiropyran molecules inside liquid crystal microspheres transforms into the open merocyanine isoform, which in turn stimulates merocyanine to translocate through the interface of the liquid crystal/dextrose emulsion. Merocyanine readily interacts with glucose molecules and causes a lowering of the emulsion’s total glucose concentration by 20 %.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"20 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81479267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Liverić, D. Iljkić, Z. Jurković, Nikša Čatipović, Paweł M. Nuckowski, O. Bialas
In this paper, the corrosion behaviour of 42CrMo4 low-alloy steel after normalizing, soft annealing, spheroidizing annealing and full annealing is investigated. 42CrMo4 is steel for quenching and tempering, and one of the widely used and studied steels due to its good combination of mechanical properties. Sometimes, it is used in the annealed condition. Nevertheless, the corrosion properties of 42CrMo4 steel are poorly studied, especially in the annealed condition. The main objective of this work is to increase the knowledge about the corrosion behaviour of the investigated alloy. The mechanical and microstructure properties of the samples after different annealing processes were characterised with hardness testing, optical and scanning electron microscopy (SEM) and X-ray diffraction (XRD). Measurements of the open-circuit potential and potentiodynamic polarisation of the samples after different annealing processes were carried out in a naturally aerated solution. It was found that the corrosion rate of the soft annealed samples was higher than that of the spherical and full annealed samples. Moreover, full annealing resulted in a significant improvement in the corrosion resistance.
{"title":"CORROSION BEHAVIOUR OF ANNEALED 42CrMo4 STEEL","authors":"L. Liverić, D. Iljkić, Z. Jurković, Nikša Čatipović, Paweł M. Nuckowski, O. Bialas","doi":"10.17222/mit.2022.624","DOIUrl":"https://doi.org/10.17222/mit.2022.624","url":null,"abstract":"In this paper, the corrosion behaviour of 42CrMo4 low-alloy steel after normalizing, soft annealing, spheroidizing annealing and full annealing is investigated. 42CrMo4 is steel for quenching and tempering, and one of the widely used and studied steels due to its good combination of mechanical properties. Sometimes, it is used in the annealed condition. Nevertheless, the corrosion properties of 42CrMo4 steel are poorly studied, especially in the annealed condition. The main objective of this work is to increase the knowledge about the corrosion behaviour of the investigated alloy. The mechanical and microstructure properties of the samples after different annealing processes were characterised with hardness testing, optical and scanning electron microscopy (SEM) and X-ray diffraction (XRD). Measurements of the open-circuit potential and potentiodynamic polarisation of the samples after different annealing processes were carried out in a naturally aerated solution. It was found that the corrosion rate of the soft annealed samples was higher than that of the spherical and full annealed samples. Moreover, full annealing resulted in a significant improvement in the corrosion resistance.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"85 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85365477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on pure melting, multi-type and fine-microstructure design, a ferritic steel with an outstanding combination of cryogenic impact toughness and strength was fabricated. The microstructure was characterized by means of optical microscopy, electron back-scattered diffraction and transmission electron microscopy. The steels with different final cooling temperatures of 663 °C and 560 °C show ferrite and perlite microstructure, and ferrite grain size can be refined from 3.15 µm to 2.67 µm by lowering the final cooling temperature from 663 °C to 560 °C. Moreover, a higher volume fraction of acicular ferrite and polygonal ferrite can be obtained for a lower final cooling temperature of 560 °C. Hence, the cryogenic impact toughness can be enhanced, and the brittle failure can be suppressed, even at –110 °C, showing a higher impact toughness compared with other ferritic steels.
{"title":"ENHANCING THE CRYOGENIC IMPACT TOUGHNESS OF FERRITIC STEEL BY MULTI-TYPE AND FINE-MICROSTRUCTURE DESIGN","authors":"","doi":"10.17222/mit.2020.234","DOIUrl":"https://doi.org/10.17222/mit.2020.234","url":null,"abstract":"Based on pure melting, multi-type and fine-microstructure design, a ferritic steel with an outstanding combination of cryogenic impact toughness and strength was fabricated. The microstructure was characterized by means of optical microscopy, electron back-scattered diffraction and transmission electron microscopy. The steels with different final cooling temperatures of 663 °C and 560 °C show ferrite and perlite microstructure, and ferrite grain size can be refined from 3.15 µm to 2.67 µm by lowering the final cooling temperature from 663 °C to 560 °C. Moreover, a higher volume fraction of acicular ferrite and polygonal ferrite can be obtained for a lower final cooling temperature of 560 °C. Hence, the cryogenic impact toughness can be enhanced, and the brittle failure can be suppressed, even at –110 °C, showing a higher impact toughness compared with other ferritic steels.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"9 3 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78695680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using recycled wastes and industrial by-products in construction materials has become mandatory to conserve the natural resources and manage waste-disposal environmental problems. This experimental work investigates the workability and strength properties of reactive powder concrete (RPC), utilizing slag powder and finely ground recycled concrete waste as the partial substitutes for cement and quartz sand, respectively. The results for the slump flow, flexural strength, compressive strength, split-tensile strength were analysed for varying contents of the recycled concrete waste in RPC, i.e., (0, 5, 10, 15, 20, 25 and 30) % and a constant slag-powder addition of 20 %. Furthermore, water absorption of the hardened specimens of 28 d of curing was also examined. The results indicated a rise in the water absorption and reduced workability with the increase in the content of recycled concrete in RPC. This was due to porous inter-particle voids in recycled concrete wastes. The strength properties of RPC exhibited superior performance for the substitution of 15 % of quartz sand with recycled concrete waste. A low water-cement ratio and a steel-fibre addition to RPC play an important role in the strength development and durability properties of RPC.
{"title":"UTILIZATION OF SLAG POWDER AND RECYCLED CONCRETE WASTES IN REACTIVE POWDER CONCRETE","authors":"S. N, G. Shiny Brintha","doi":"10.17222/mit.2022.701","DOIUrl":"https://doi.org/10.17222/mit.2022.701","url":null,"abstract":"Using recycled wastes and industrial by-products in construction materials has become mandatory to conserve the natural resources and manage waste-disposal environmental problems. This experimental work investigates the workability and strength properties of reactive powder concrete (RPC), utilizing slag powder and finely ground recycled concrete waste as the partial substitutes for cement and quartz sand, respectively. The results for the slump flow, flexural strength, compressive strength, split-tensile strength were analysed for varying contents of the recycled concrete waste in RPC, i.e., (0, 5, 10, 15, 20, 25 and 30) % and a constant slag-powder addition of 20 %. Furthermore, water absorption of the hardened specimens of 28 d of curing was also examined. The results indicated a rise in the water absorption and reduced workability with the increase in the content of recycled concrete in RPC. This was due to porous inter-particle voids in recycled concrete wastes. The strength properties of RPC exhibited superior performance for the substitution of 15 % of quartz sand with recycled concrete waste. A low water-cement ratio and a steel-fibre addition to RPC play an important role in the strength development and durability properties of RPC.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"9 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87280670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Fu, Yunhan Ling, Peng Jiang, Yong Sun, Chao Yuan, Xiaoming Du
The aluminium-matrix composites (AMCs) consisted of (5, 10 and 15) x/% SiC particles (SiCp) in an aluminium alloy 7055 matrix. Specimens were taken from hot-press sintering. High-strain-rate tests were performed using the split-Hopkinson pressure bar (SHPB) method. The microstructures were observed with a scanning electron microscope (SEM) to understand the damage mechanisms of the SiCp/7055 Al composites at high strain rate. The SHPB test results show that the SiCp-reinforced composites are more sensitive to strain rate than the unreinforced material. The strain-rate sensitivity of the flow stress of these composites increases substantially with the increase of the strain rate. The flow stress of SiCp/7055Al composites with 10 x/% and 15 x/% SiCp at 3000 s–1 first increases and then decreases with the increase of the plastic strains, which was caused by the heat generated during adiabatic compression. Microstructure-characterization results show that SiCp cracking and SiCp/7055Al interface debonding are the main damage mechanisms of the composites. The SiCp volume fraction and strain rate affect the damage of composites during the dynamic compressive deformation of the SiCp /7055Al composites.
{"title":"DYNAMIC COMPRESSIVE PROPERTIES OF ALUMINIUM-MATRIX COMPOSITES REINFORCED WITH SiC PARTICLES","authors":"D. Fu, Yunhan Ling, Peng Jiang, Yong Sun, Chao Yuan, Xiaoming Du","doi":"10.17222/mit.2022.580","DOIUrl":"https://doi.org/10.17222/mit.2022.580","url":null,"abstract":"The aluminium-matrix composites (AMCs) consisted of (5, 10 and 15) x/% SiC particles (SiCp) in an aluminium alloy 7055 matrix. Specimens were taken from hot-press sintering. High-strain-rate tests were performed using the split-Hopkinson pressure bar (SHPB) method. The microstructures were observed with a scanning electron microscope (SEM) to understand the damage mechanisms of the SiCp/7055 Al composites at high strain rate. The SHPB test results show that the SiCp-reinforced composites are more sensitive to strain rate than the unreinforced material. The strain-rate sensitivity of the flow stress of these composites increases substantially with the increase of the strain rate. The flow stress of SiCp/7055Al composites with 10 x/% and 15 x/% SiCp at 3000 s–1 first increases and then decreases with the increase of the plastic strains, which was caused by the heat generated during adiabatic compression. Microstructure-characterization results show that SiCp cracking and SiCp/7055Al interface debonding are the main damage mechanisms of the composites. The SiCp volume fraction and strain rate affect the damage of composites during the dynamic compressive deformation of the SiCp /7055Al composites.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"40 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84588024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sriram Pradeep Saridhe, M. Hareesh, Shanmuga Priya T, T. Selvaraj
Construction industry is majorly criticised due to a great liberation of carbon dioxide (CO2) into the atmosphere. Researchers have identified various techniques to capture the atmospheric CO2. Nevertheless, the recognised methods have both merits as well as demerits. Thus, scientific communities are working on simple and easily exhibited ways of capturing atmospheric CO2. One such technique is the conversion of gaseous CO2 into stable calcium/magnesium carbonates. The present study was conducted to identify the carbon-capturing efficiency of olivine aggregate in cement and lime mortars. Olivine aggregate has a tendency to change its mineral structure under alkaline environment and it is able to interact with atmospheric CO2 to form a stable carbonate. Analytical techniques (XRD, TGA) were conducted to elucidate the formation of hydrated phases formed in both lime and cement mortars. The study concluded that the addition of olivine sequestered atmospheric CO2 and converted it into magnesium carbonate. Out of the lime and cement mortar, lime mortar captured a greater amount of CO2 and produced stable compounds.
{"title":"ROLE OF OLIVINE AGGREGATE IN LIME AND CEMENT MORTARS FOR THE SEQUESTRATION OF ATMOSPHERIC CO2","authors":"Sriram Pradeep Saridhe, M. Hareesh, Shanmuga Priya T, T. Selvaraj","doi":"10.17222/mit.2022.719","DOIUrl":"https://doi.org/10.17222/mit.2022.719","url":null,"abstract":"Construction industry is majorly criticised due to a great liberation of carbon dioxide (CO2) into the atmosphere. Researchers have identified various techniques to capture the atmospheric CO2. Nevertheless, the recognised methods have both merits as well as demerits. Thus, scientific communities are working on simple and easily exhibited ways of capturing atmospheric CO2. One such technique is the conversion of gaseous CO2 into stable calcium/magnesium carbonates. The present study was conducted to identify the carbon-capturing efficiency of olivine aggregate in cement and lime mortars. Olivine aggregate has a tendency to change its mineral structure under alkaline environment and it is able to interact with atmospheric CO2 to form a stable carbonate. Analytical techniques (XRD, TGA) were conducted to elucidate the formation of hydrated phases formed in both lime and cement mortars. The study concluded that the addition of olivine sequestered atmospheric CO2 and converted it into magnesium carbonate. Out of the lime and cement mortar, lime mortar captured a greater amount of CO2 and produced stable compounds.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"105 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76130767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tractors, high-power, low-speed traction vehicles and power units are similar to trucks or automobiles but designed for use off-road. They are defined as motor vehicles with wheels that allow them to hold on to loose terrain and be fitted with trailers. Tractors operate in challenging operating conditions. Therefore, it is possible that they become damaged. In some cases the damage is due to disrupted engineering, but more frequently, it is due to failures in material processing and maintenance, raw material errors, design and manufacturing errors, and user-related errors. This study examined the fractured front axle of a tractor. Spectroscopic, metallographic and hardness measurements of the axle parts were made. Stress analyses were also performed using finite elements to determine the stress conditions in the renewed section. The finite element analysis showed that the broken region was exposed to maximum stresses. Stress analyses using finite elements were also carried out to determine the stress conditions in the repeated section. With the fracture surface analysis, mild fatigue was observed, and it was concluded that the fracture occurred suddenly.
{"title":"FAILURE ANALYSIS OF A TRACTOR FRONT AXLE","authors":"I. Yavuz","doi":"10.17222/mit.2022.711","DOIUrl":"https://doi.org/10.17222/mit.2022.711","url":null,"abstract":"Tractors, high-power, low-speed traction vehicles and power units are similar to trucks or automobiles but designed for use off-road. They are defined as motor vehicles with wheels that allow them to hold on to loose terrain and be fitted with trailers. Tractors operate in challenging operating conditions. Therefore, it is possible that they become damaged. In some cases the damage is due to disrupted engineering, but more frequently, it is due to failures in material processing and maintenance, raw material errors, design and manufacturing errors, and user-related errors. This study examined the fractured front axle of a tractor. Spectroscopic, metallographic and hardness measurements of the axle parts were made. Stress analyses were also performed using finite elements to determine the stress conditions in the renewed section. The finite element analysis showed that the broken region was exposed to maximum stresses. Stress analyses using finite elements were also carried out to determine the stress conditions in the repeated section. With the fracture surface analysis, mild fatigue was observed, and it was concluded that the fracture occurred suddenly.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"21 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80870116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pečlin, J. Rozman, Renata Janež, Anja Emri, S. Ribaric, T. Mirkovic̆
This article reviews the development of a new concept for crafting and testing a multi-electrode set-up for selective transcutaneous auricular nerve stimulation (tANS) using particular superficial regions of the external ear (EE). The purpose of the work is to assess the mechanical properties of the set-up to ensure the optimum conditions for the users, and to test the ability to affect vital physiological functions. The set-up consisted of eight cap-like platinum simulating cathodes (S = 14.58 mm2) that were embedded in the left and right silicone ear plugs. The plugs were mounted onto the frame of dummy headphones and inserted into the EE, while a common anode (anode) (S = 4500 mm2) was placed at the nape of the neck. The mechanical performance was assessed by measuring the axial force Fx acting on each cathode against the bending of the dummy headphone frame while simulating the conditions of the set-up being mounted onto the head. The functionality was tested by applying stimuli onto four predefined sites at the EE to modify particular vital physiological functions of female volunteers. The preliminary results show that during the tANS, the bi-nasal respiration became shorter but more frequent with steeper inspiration and a lower airflow. The results also show that during the tANS, the heart rate was slightly diminished along with the respiratory sinus arrhythmia. Finally, a dicrotic notch within the toe photoplethysmogram was masked by the waves with a frequency of approximately 300 min–1. The presented work has implications for the multi-electrode set-up design and the prediction of efficient tANS used to modify physiological functions.
{"title":"MULTI-ELECTRODE TRANSCUTANEOUS ELECTRICAL STIMULATION OF THE HUMAN EXTERNAL EAR","authors":"P. Pečlin, J. Rozman, Renata Janež, Anja Emri, S. Ribaric, T. Mirkovic̆","doi":"10.17222/mit.2023.779","DOIUrl":"https://doi.org/10.17222/mit.2023.779","url":null,"abstract":"This article reviews the development of a new concept for crafting and testing a multi-electrode set-up for selective transcutaneous auricular nerve stimulation (tANS) using particular superficial regions of the external ear (EE). The purpose of the work is to assess the mechanical properties of the set-up to ensure the optimum conditions for the users, and to test the ability to affect vital physiological functions. The set-up consisted of eight cap-like platinum simulating cathodes (S = 14.58 mm2) that were embedded in the left and right silicone ear plugs. The plugs were mounted onto the frame of dummy headphones and inserted into the EE, while a common anode (anode) (S = 4500 mm2) was placed at the nape of the neck. The mechanical performance was assessed by measuring the axial force Fx acting on each cathode against the bending of the dummy headphone frame while simulating the conditions of the set-up being mounted onto the head. The functionality was tested by applying stimuli onto four predefined sites at the EE to modify particular vital physiological functions of female volunteers. The preliminary results show that during the tANS, the bi-nasal respiration became shorter but more frequent with steeper inspiration and a lower airflow. The results also show that during the tANS, the heart rate was slightly diminished along with the respiratory sinus arrhythmia. Finally, a dicrotic notch within the toe photoplethysmogram was masked by the waves with a frequency of approximately 300 min–1. The presented work has implications for the multi-electrode set-up design and the prediction of efficient tANS used to modify physiological functions.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"01 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85959767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, alumina and multi-wall carbon nanotube (MWCNT) hybrid nanofiller reinforcing pure epoxy at varying weight fractions of (0.1, 0.2, 0.3, 0.4 and 0.5) w/% is investigated to enhance the mechanical, electrical and thermal properties. The porosity, tensile strength, electrical and thermal conductivity of epoxy hybrid nanocomposites are studied after the effects of the alumina-MWCNT hybrid nanofillers. The interfacial adhesion and mechanical interlocking between the hybrid nanofillers and epoxy are greatly increased with the addition of alumina and MWCNTs, thus leading to an improvement in the mechanical properties. Additionally, a uniform distribution of hybrid nanofillers results in a larger increase in the thermal and electrical conductivity. The presence of voids in specimens is gradually decreased when the nanofiller content is increased up to 0.3 w/%. The alumina-MWCNT reinforcement significantly improves the tensile strength, by 88 %, compared with pure epoxy. Similarly, the electrical and thermal conductivity increase by 85 % and 64 %, respectively, when compared with low weight fractions of the hybrid nanofiller. Agglomeration during the fabrication of nanocomposites is manageable but it is inevitable. During the formation of chains and networks, the alumina-MWCNT reinforcement of pure epoxy greatly influences the thermal conductivity. This strategy provides a prospective new concept for the use of epoxy and its composites in structural and thermal engineering applications.
{"title":"ENHANCING THE MECHANICAL, THERMAL AND ELECTRICAL PROPERTIES OF ALUMINA-MWCNT HYBRID NANOFILLER REINFORCED EPOXY COMPOSITES","authors":"","doi":"10.17222/mit.2022.684","DOIUrl":"https://doi.org/10.17222/mit.2022.684","url":null,"abstract":"In this work, alumina and multi-wall carbon nanotube (MWCNT) hybrid nanofiller reinforcing pure epoxy at varying weight fractions of (0.1, 0.2, 0.3, 0.4 and 0.5) w/% is investigated to enhance the mechanical, electrical and thermal properties. The porosity, tensile strength, electrical and thermal conductivity of epoxy hybrid nanocomposites are studied after the effects of the alumina-MWCNT hybrid nanofillers. The interfacial adhesion and mechanical interlocking between the hybrid nanofillers and epoxy are greatly increased with the addition of alumina and MWCNTs, thus leading to an improvement in the mechanical properties. Additionally, a uniform distribution of hybrid nanofillers results in a larger increase in the thermal and electrical conductivity. The presence of voids in specimens is gradually decreased when the nanofiller content is increased up to 0.3 w/%. The alumina-MWCNT reinforcement significantly improves the tensile strength, by 88 %, compared with pure epoxy. Similarly, the electrical and thermal conductivity increase by 85 % and 64 %, respectively, when compared with low weight fractions of the hybrid nanofiller. Agglomeration during the fabrication of nanocomposites is manageable but it is inevitable. During the formation of chains and networks, the alumina-MWCNT reinforcement of pure epoxy greatly influences the thermal conductivity. This strategy provides a prospective new concept for the use of epoxy and its composites in structural and thermal engineering applications.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"09 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85861834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study was to evaluate the effects of three-dimensional (3D)-printed zirconia all-ceramic crowns on the periodontal tissues and aesthetics of patients receiving anterior tooth aesthetic restoration. A total of 85 patients with anterior tooth defects treated from January 2018 to October 2019 were selected. We studied zirconia all-ceramic crowns made by computer-aided design and computer-aided manufacturing (CAD/CAM) (control group) and 3D printing (observation group). The short-term restoration effects, periodontal health indices, functional recovery, long-term clinical efficacy and aesthetic effects were compared. The gingival marginal fitness of the observation group was better than that of the control group, but the control group had better tooth color matching (P < 0.05). One year after the restoration, the bleeding index, probing depth, attachment loss, gingival index and plaque index all declined in the two groups, particularly in the observation group. Both the masticatory and language functions were improved in the two groups, especially in the observation group (P < 0.05). Both 3D-printed and CAD/CAM zirconia all-ceramic crowns have better cosmetic restoration effects on the anterior teeth. However, 3D-printed zirconia all-ceramic crowns have better gingival marginal fitness, which can benefit the periodontal tissue recovery, relieve gingival inflammation, and improve masticatory and language functions.
{"title":"EFFECTS OF THREE-DIMENSIONAL-PRINTED ZIRCONIA ALL-CERAMIC CROWNS ON PERIODONTAL HEALTH AND AESTHETICS OF PATIENTS RECEIVING ANTERIOR TOOTH AESTHETIC RESTORATION","authors":"Fengxian Li, Wei Li","doi":"10.17222/mit.2023.738","DOIUrl":"https://doi.org/10.17222/mit.2023.738","url":null,"abstract":"The aim of this study was to evaluate the effects of three-dimensional (3D)-printed zirconia all-ceramic crowns on the periodontal tissues and aesthetics of patients receiving anterior tooth aesthetic restoration. A total of 85 patients with anterior tooth defects treated from January 2018 to October 2019 were selected. We studied zirconia all-ceramic crowns made by computer-aided design and computer-aided manufacturing (CAD/CAM) (control group) and 3D printing (observation group). The short-term restoration effects, periodontal health indices, functional recovery, long-term clinical efficacy and aesthetic effects were compared. The gingival marginal fitness of the observation group was better than that of the control group, but the control group had better tooth color matching (P < 0.05). One year after the restoration, the bleeding index, probing depth, attachment loss, gingival index and plaque index all declined in the two groups, particularly in the observation group. Both the masticatory and language functions were improved in the two groups, especially in the observation group (P < 0.05). Both 3D-printed and CAD/CAM zirconia all-ceramic crowns have better cosmetic restoration effects on the anterior teeth. However, 3D-printed zirconia all-ceramic crowns have better gingival marginal fitness, which can benefit the periodontal tissue recovery, relieve gingival inflammation, and improve masticatory and language functions.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"6 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82039174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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