This research was focused on the homogeneous precipitation synthesis of a series of Eu3+ ion-activated ellipsoidal La2O2SO4 phosphors based on the La2(SO4)3-CO(NH2)2 reaction system. The structural identification, thermal analysis, morphology and luminescence properties of the as-prepared products were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG/DSC), field emission scanning electron microscopy (FESEM) and photoluminescence (PL) spectra. Pure La2O2SO4 ellipsoidal particles with a long radius of about 2 µm and a short radius of about 1 µm were successfully prepared by calcining a rhombus-like precursor at 800 °C for 2 h in air. The formation mechanism of the precursor and its corresponding calcination product were also proposed. Photoluminescence results revealed that the strongest red emission peak was centered at 619 nm upon 249-nm ultraviolet (UV) light excitation in La2O2SO4:x%Eu3+ (x = 3, 6, 9, 12 and 15) phosphors. The exchange interaction was responsible for the concentration quenching mechanism of the 5D0→7F2 transition of Eu3+ ions in the La2O2SO4 host lattice. The optimal x value was 15 and the corresponding decay process showed a single exponential decay behavior whose lifetime t and color correlation temperature (CCT) were calculated to be 2.112 ms and 2752 K, respectively.
{"title":"SYNTHESIS AND PHOTOLUMINESCENCE PROPERTIES OF ELLIPSOIDAL La2O2SO4:Eu3+ PHOSPHORS","authors":"Xing Li, L. Gao, J. Lian","doi":"10.17222/mit.2022.634","DOIUrl":"https://doi.org/10.17222/mit.2022.634","url":null,"abstract":"This research was focused on the homogeneous precipitation synthesis of a series of Eu3+ ion-activated ellipsoidal La2O2SO4 phosphors based on the La2(SO4)3-CO(NH2)2 reaction system. The structural identification, thermal analysis, morphology and luminescence properties of the as-prepared products were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG/DSC), field emission scanning electron microscopy (FESEM) and photoluminescence (PL) spectra. Pure La2O2SO4 ellipsoidal particles with a long radius of about 2 µm and a short radius of about 1 µm were successfully prepared by calcining a rhombus-like precursor at 800 °C for 2 h in air. The formation mechanism of the precursor and its corresponding calcination product were also proposed. Photoluminescence results revealed that the strongest red emission peak was centered at 619 nm upon 249-nm ultraviolet (UV) light excitation in La2O2SO4:x%Eu3+ (x = 3, 6, 9, 12 and 15) phosphors. The exchange interaction was responsible for the concentration quenching mechanism of the 5D0→7F2 transition of Eu3+ ions in the La2O2SO4 host lattice. The optimal x value was 15 and the corresponding decay process showed a single exponential decay behavior whose lifetime t and color correlation temperature (CCT) were calculated to be 2.112 ms and 2752 K, respectively.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"37 7 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79145887","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}
This paper reports the effect of incorporating Inconel particles as filler for enhancing the delamination and mechanical strength of glass-fiber-reinforced epoxy composites. It is intended for application in renewable energy. Glass fiber plays a vital role in renewable-energy industries for its non-corrosiveness and lower maintenance cost. The mechanical properties of glass fibers make the renewable industry for effective utilization in the manufacturing of turbine blades in onshore and offshore environments, as well as the addition of fillers enhances the mechanical properties of the material. This study comprises validating three different compositions of Inconel blended with epoxy resin for the preparation of laminates using a vacuum-infusion process. The tensile and flexural properties of the composites were experimentally examined and validated for the enhanced use of structural applications in the field of renewable energy. In addition to the mechanical characterization, a finite-element validation was used to determine the delamination effect. The Ansys Composite PrePost (ACP) module was used to validate the Inconel-blended composite materials. The flammability characteristics were determined as per the UL-94 standard for both vertical and horizontal flame tests. The water-absorption characteristics were also estimated for the three different proportions of the Inconel-filled laminates. The study reveals that the incorporation of Inconel powder enhanced the mechanical properties, contact angle and the fire-retardant characteristics of the glass-fiber epoxy-blended laminates.
{"title":"INVESTIGATION OF THE EFFECT OF INCONEL PARTICULATE FILLER ON THE MECHANICAL AND FIRE-RETARDANT CHARACTERISTICS OF GFRP COMPOSITES","authors":"R. Karthikeyan, Rajkumar Subbiah","doi":"10.17222/mit.2022.559","DOIUrl":"https://doi.org/10.17222/mit.2022.559","url":null,"abstract":"This paper reports the effect of incorporating Inconel particles as filler for enhancing the delamination and mechanical strength of glass-fiber-reinforced epoxy composites. It is intended for application in renewable energy. Glass fiber plays a vital role in renewable-energy industries for its non-corrosiveness and lower maintenance cost. The mechanical properties of glass fibers make the renewable industry for effective utilization in the manufacturing of turbine blades in onshore and offshore environments, as well as the addition of fillers enhances the mechanical properties of the material. This study comprises validating three different compositions of Inconel blended with epoxy resin for the preparation of laminates using a vacuum-infusion process. The tensile and flexural properties of the composites were experimentally examined and validated for the enhanced use of structural applications in the field of renewable energy. In addition to the mechanical characterization, a finite-element validation was used to determine the delamination effect. The Ansys Composite PrePost (ACP) module was used to validate the Inconel-blended composite materials. The flammability characteristics were determined as per the UL-94 standard for both vertical and horizontal flame tests. The water-absorption characteristics were also estimated for the three different proportions of the Inconel-filled laminates. The study reveals that the incorporation of Inconel powder enhanced the mechanical properties, contact angle and the fire-retardant characteristics of the glass-fiber epoxy-blended laminates.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"136 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88949251","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}
Athithanambi Anna Anban, Manonmani Krishnaswamy, Rajesh Appasamy
The biodegradability and environmental friendliness of natural fibres makes them suitable for implementation in a circular economy. As a result, several natural fibres and processing methods have evolved. The hydrophilic nature of ligno cellulose fibrils restricts the effective adhesion at the interface of fibre and matrix. The hybridization of natural fibres with synthetic fibres leads to promising characteristics of the resulting composite materials. This paper deals with the hybridization of conventional glass fibre and natural fibre extracted from coconut inflorescence. The effect of hybridization on the tensile and flexural strengths of surface-modified inflorescence fibre with glass fibres was investigated. The composites were fabricated using a hand-layup technique by varying the inflorescence fibre and glass-fibre reinforcement composition by (5, 10, 15 and 20) %. A notable improvement in the tensile and flexural strengths of 193.65 MPa and 240.69 MPa was observed for 85 % of glass and 15 % of benzoyl-chloride-modified inflorescence-fibre-reinforced hybrid composites. The elimination of amorphous constituents in the inflorescence fibres was checked by XRD and FTIR analyses. A surface-morphology analysis of unmodified and benzoyl-chloride-modified inflorescence fibres revealed pores and cavity formation on the fibril walls. These composites with superior mechanical properties can be an alternative to synthetic fibre composites and ensure the implementation of a circular economy and sustainable manufacturing.
{"title":"MECHANICAL BEHAVIOUR OF INFLORESCENCE/GLASS-FIBRE-REINFORCED HYBRID EPOXY COMPOSITES","authors":"Athithanambi Anna Anban, Manonmani Krishnaswamy, Rajesh Appasamy","doi":"10.17222/mit.2022.588","DOIUrl":"https://doi.org/10.17222/mit.2022.588","url":null,"abstract":"The biodegradability and environmental friendliness of natural fibres makes them suitable for implementation in a circular economy. As a result, several natural fibres and processing methods have evolved. The hydrophilic nature of ligno cellulose fibrils restricts the effective adhesion at the interface of fibre and matrix. The hybridization of natural fibres with synthetic fibres leads to promising characteristics of the resulting composite materials. This paper deals with the hybridization of conventional glass fibre and natural fibre extracted from coconut inflorescence. The effect of hybridization on the tensile and flexural strengths of surface-modified inflorescence fibre with glass fibres was investigated. The composites were fabricated using a hand-layup technique by varying the inflorescence fibre and glass-fibre reinforcement composition by (5, 10, 15 and 20) %. A notable improvement in the tensile and flexural strengths of 193.65 MPa and 240.69 MPa was observed for 85 % of glass and 15 % of benzoyl-chloride-modified inflorescence-fibre-reinforced hybrid composites. The elimination of amorphous constituents in the inflorescence fibres was checked by XRD and FTIR analyses. A surface-morphology analysis of unmodified and benzoyl-chloride-modified inflorescence fibres revealed pores and cavity formation on the fibril walls. These composites with superior mechanical properties can be an alternative to synthetic fibre composites and ensure the implementation of a circular economy and sustainable manufacturing.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"66 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89502956","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 wall slip of magnetorheological (MR) fluids refers to a phenomenon that affects the application of mechanical properties of magnetorheological fluids due to the relative slippage between the magnetic particles and the transmission wall. In this paper, we analyze and experimentally verify the factors affecting the wall slip of magnetorheological fluids, which can limit the application of magnetorheological-fluid devices. Firstly, from the theoretical point of view, it is considered that the influencing factors are mainly divided into two parts: magnetorheological fluid’s own parameters and transmission surface roughness, among which the parameters include viscosity, mass fraction, etc. When studying the influence of the transmission surface roughness, it is found that different surface morphologies have a great influence on the shear stress. Secondly, a magnetic field simulation analysis and shear yield stress experiments are conducted on shear blocks with different surface morphologies; the obtained results are compared and verified, confirming that different surface shapes affect the shear yield stress by changing the magnetic field distribution of the groove, which in turn changes the wall slip characteristics. These findings provide an effective basis for further research on the wall slip of magnetorheological fluids to improve the transmission effect.
{"title":"STUDY OF FACTORS INFLUENCING THE WALL SLIP OF A MAGNETORHEOLOGICAL FLUID","authors":"Qibo Fang, Yiping Luo, Weicheng Wang, Shicheng Wang, Shichong Song, Luyun Zhang","doi":"10.17222/mit.2022.643","DOIUrl":"https://doi.org/10.17222/mit.2022.643","url":null,"abstract":"The wall slip of magnetorheological (MR) fluids refers to a phenomenon that affects the application of mechanical properties of magnetorheological fluids due to the relative slippage between the magnetic particles and the transmission wall. In this paper, we analyze and experimentally verify the factors affecting the wall slip of magnetorheological fluids, which can limit the application of magnetorheological-fluid devices. Firstly, from the theoretical point of view, it is considered that the influencing factors are mainly divided into two parts: magnetorheological fluid’s own parameters and transmission surface roughness, among which the parameters include viscosity, mass fraction, etc. When studying the influence of the transmission surface roughness, it is found that different surface morphologies have a great influence on the shear stress. Secondly, a magnetic field simulation analysis and shear yield stress experiments are conducted on shear blocks with different surface morphologies; the obtained results are compared and verified, confirming that different surface shapes affect the shear yield stress by changing the magnetic field distribution of the groove, which in turn changes the wall slip characteristics. These findings provide an effective basis for further research on the wall slip of magnetorheological fluids to improve the transmission effect.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89489595","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}
A bimetal composite plate including a high-chromium cast iron (HCCI) and low-carbon steel (LCS) cladding was fabricated with hot-rolling bonding in the form of a sandwich structure. In this work, the microstructure and mechanical properties of the bimetal composite were analyzed. Experimental results showed that the brittle HCCI layer achieved good thermoplastic deformation under the action of carbon-steel cladding. After hot rolling, the two metals were well bonded due to mechanical and metallurgical bonding, showing an excellent joint. C atoms diffused uphill the interface. A decarburization area was formed near the LCS side and a fine pearlite diffusion band with a thickness of about 2–3 µm was formed on the bonding interface. The tensile strength of the bimetal composite was 249.5 MPa, and a cleavage fracture appeared on the HCCI side. Interfacial delamination cracks and tunnel cracks of the HCCI were observed in the bimetal composite during a bending test.
{"title":"PROPERTIES OF HIGH-CHROMIUM CAST IRON/LOW-CARBON STEEL BIMETAL FABRICATED BY HOT-ROLLING","authors":"G. Yuan, Xianke Xiao, Fei Zhao","doi":"10.17222/mit.2022.589","DOIUrl":"https://doi.org/10.17222/mit.2022.589","url":null,"abstract":"A bimetal composite plate including a high-chromium cast iron (HCCI) and low-carbon steel (LCS) cladding was fabricated with hot-rolling bonding in the form of a sandwich structure. In this work, the microstructure and mechanical properties of the bimetal composite were analyzed. Experimental results showed that the brittle HCCI layer achieved good thermoplastic deformation under the action of carbon-steel cladding. After hot rolling, the two metals were well bonded due to mechanical and metallurgical bonding, showing an excellent joint. C atoms diffused uphill the interface. A decarburization area was formed near the LCS side and a fine pearlite diffusion band with a thickness of about 2–3 µm was formed on the bonding interface. The tensile strength of the bimetal composite was 249.5 MPa, and a cleavage fracture appeared on the HCCI side. Interfacial delamination cracks and tunnel cracks of the HCCI were observed in the bimetal composite during a bending test.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"18 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79275644","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}
Aiming at the problems of asphalt pavement crack sealing and pothole repair materials, an epoxy-resin adhesive with high forming strength, good toughness and room-temperature curing was prepared. In addition to being used as a road filling sealant, the adhesive can also be used for preparing a cold patching mixture for pits. The properties of the epoxy-resin adhesive, the construction performance and road performance of the pouring sealant and cold patch were studied. The results showed that the early strength of the epoxy-resin adhesive was fast and high, the curing volume shrinkage was small, the low-temperature characteristics and tensile properties were good, and the toughness was excellent. As a pouring sealant, the epoxy-resin adhesive had excellent low-temperature bending resistance. The cold patching mixture based on the adhesive exhibited strong cohesiveness, good low-temperature crack resistance, and excellent high-temperature stability and water stability. This adhesive expands the application of epoxy resin in repairing cracks and pits of asphalt pavements, and is of great significance in promoting the development of the asphalt pavement maintenance technology.
{"title":"EPOXY-RESIN ADHESIVE FOR SEAM FILLING AND POTHOLE REPAIR IN PAVEMENT MAINTENANCE","authors":"Chengping He, Zhigang Wu, Yu Huang, Jiangang Yang, Cong Liang, Guanfa Zhang","doi":"10.17222/mit.2022.531","DOIUrl":"https://doi.org/10.17222/mit.2022.531","url":null,"abstract":"Aiming at the problems of asphalt pavement crack sealing and pothole repair materials, an epoxy-resin adhesive with high forming strength, good toughness and room-temperature curing was prepared. In addition to being used as a road filling sealant, the adhesive can also be used for preparing a cold patching mixture for pits. The properties of the epoxy-resin adhesive, the construction performance and road performance of the pouring sealant and cold patch were studied. The results showed that the early strength of the epoxy-resin adhesive was fast and high, the curing volume shrinkage was small, the low-temperature characteristics and tensile properties were good, and the toughness was excellent. As a pouring sealant, the epoxy-resin adhesive had excellent low-temperature bending resistance. The cold patching mixture based on the adhesive exhibited strong cohesiveness, good low-temperature crack resistance, and excellent high-temperature stability and water stability. This adhesive expands the application of epoxy resin in repairing cracks and pits of asphalt pavements, and is of great significance in promoting the development of the asphalt pavement maintenance technology.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"40 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91070297","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}
Aljaž Merčun, R. Košak, M. Jenko, J. Kovač, Miha Vodičar
The treatment of early-onset scoliosis (EOS) remains one of the biggest challenges in paediatric orthopaedics. Magnetically controlled growing rods (MCGRs) have increased in popularity compared to traditional growing rods (TGRs), providing curve correction, spinal growth and a reduction of the associated surgical trauma. Between May 2015 and July 2022, 24 patients with EOS were treated with an MCGR system using a standardized implantation procedure. An ultrasonography- or radiography-controlled distraction of 3 mm every 3 months was performed. Whole spine radiographs were taken pre-operatively, post-operatively, and in six month interval. The Cobb angle, T1-S1 height, and growth were measured. All the patients had a dual-rod construct implantation. The mean age of the surgical patients was 8 years (6–11), and the mean follow up was 39 months (2–84). The etiology of the EOS was syndromic in six patients, congenital in two, idiopathic in three and neuromuscular in 12. One patient had a conversion from TGR, and one patient had a concomitant resection of hemivertebra. The mean preoperative Cobb angle was 69° (30–108°), postoperative was 38° (16–66°), and 38° (9–69°) at final follow-up. The mean pre-operative T1–S1 length was 289 mm, increasing to 326 mm post-operatively, and 353 mm at the final follow-up. The mean spinal growth was 64 mm (26–110 mm). Two retrieved rods were examined using X-ray photoelectron spectroscopy (XPS). A surface analytical technique to determine the surface chemistry after exposure of the rods in the body. The MCGR system represents a safe and less invasive option for the treatment of EOS.
早发性脊柱侧凸(EOS)的治疗仍然是儿科骨科面临的最大挑战之一。与传统的生长棒(tgr)相比，磁控生长棒(mcgr)越来越受欢迎，提供曲线矫正，脊柱生长和减少相关的手术创伤。2015年5月至2022年7月期间，24名EOS患者接受了MCGR系统的标准化植入治疗。每3个月进行一次超声或x线片控制的3mm牵张。术前、术后及间隔6个月拍摄全脊柱x线片。测量Cobb角、T1-S1高度和生长情况。所有患者均行双棒植入。手术患者平均年龄8岁(6-11岁)，平均随访39个月(2-84岁)。EOS的病因为6例综合征，2例先天性，3例特发性，12例神经肌肉性。1例患者从TGR进行了转换，1例患者同时切除了半椎体。术前平均Cobb角为69°(30-108°)，术后平均Cobb角为38°(16-66°)，最终随访时平均Cobb角为38°(9-69°)。术前T1-S1平均长度为289 mm，术后增加至326 mm，最终随访时为353 mm。脊髓平均生长64 mm (26 ~ 110 mm)。用x射线光电子能谱(XPS)对两根回收棒进行了检测。一种表面分析技术，用于测定暴露在体内的金属棒后的表面化学性质。MCGR系统是治疗EOS的一种安全且侵入性较小的选择。
{"title":"MAGNETICALLY CONTROLLED GROWING RODS FOR THE TREATMENT OF EOS: EXPERIENCE FROM A SINGLE CENTER AND XPS SURFACE ANALYSIS OF THE RODS","authors":"Aljaž Merčun, R. Košak, M. Jenko, J. Kovač, Miha Vodičar","doi":"10.17222/mit.2022.565","DOIUrl":"https://doi.org/10.17222/mit.2022.565","url":null,"abstract":"The treatment of early-onset scoliosis (EOS) remains one of the biggest challenges in paediatric orthopaedics. Magnetically controlled growing rods (MCGRs) have increased in popularity compared to traditional growing rods (TGRs), providing curve correction, spinal growth and a reduction of the associated surgical trauma. Between May 2015 and July 2022, 24 patients with EOS were treated with an MCGR system using a standardized implantation procedure. An ultrasonography- or radiography-controlled distraction of 3 mm every 3 months was performed. Whole spine radiographs were taken pre-operatively, post-operatively, and in six month interval. The Cobb angle, T1-S1 height, and growth were measured. All the patients had a dual-rod construct implantation. The mean age of the surgical patients was 8 years (6–11), and the mean follow up was 39 months (2–84). The etiology of the EOS was syndromic in six patients, congenital in two, idiopathic in three and neuromuscular in 12. One patient had a conversion from TGR, and one patient had a concomitant resection of hemivertebra. The mean preoperative Cobb angle was 69° (30–108°), postoperative was 38° (16–66°), and 38° (9–69°) at final follow-up. The mean pre-operative T1–S1 length was 289 mm, increasing to 326 mm post-operatively, and 353 mm at the final follow-up. The mean spinal growth was 64 mm (26–110 mm). Two retrieved rods were examined using X-ray photoelectron spectroscopy (XPS). A surface analytical technique to determine the surface chemistry after exposure of the rods in the body. The MCGR system represents a safe and less invasive option for the treatment of EOS.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"97 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86358669","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}
By characterizing the properties of a twin cast-rolled AZ31 sheet after cryogenic rolling, the effects of the initial temperature on the microstructure and mechanical properties of the sheet obtained by cryogenic rolling were studied. The results indicate that the hardness of the alloy was a maximum due to the high-density dislocations in the microstructure when the initial temperature was room temperature. The highest yield strength and elongation appeared at the initial temperature of 200 °C, and the microstructure was mainly fine equiaxed grains. It was observed that fine grains increased, and the yield strength and elongation gradually decreased with the increase of the initial temperature. The overall trend of yield strength and elongation increased first and then decreased. Based on the results of different initial temperature treatments, the optimal microstructure and properties of AZ31 magnesium alloy were acquired when the initial temperature was 200 °C.
{"title":"EFFECT OF INITIAL TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF CRYOGENIC ROLLED AZ31 MAGNESIUM ALLOY","authors":"Zhenyu Wu, Chenchen Zhi, Lifeng Ma, Z. Zheng, Yanchun Zhu, Weitao Jia","doi":"10.17222/mit.2022.443","DOIUrl":"https://doi.org/10.17222/mit.2022.443","url":null,"abstract":"By characterizing the properties of a twin cast-rolled AZ31 sheet after cryogenic rolling, the effects of the initial temperature on the microstructure and mechanical properties of the sheet obtained by cryogenic rolling were studied. The results indicate that the hardness of the alloy was a maximum due to the high-density dislocations in the microstructure when the initial temperature was room temperature. The highest yield strength and elongation appeared at the initial temperature of 200 °C, and the microstructure was mainly fine equiaxed grains. It was observed that fine grains increased, and the yield strength and elongation gradually decreased with the increase of the initial temperature. The overall trend of yield strength and elongation increased first and then decreased. Based on the results of different initial temperature treatments, the optimal microstructure and properties of AZ31 magnesium alloy were acquired when the initial temperature was 200 °C.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"4 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87325290","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}
A chitosan/attapulgite (CS/ATP) composite flocculant with excellent adsorption was prepared from chitosan (CS) and attapulgite clay (ATP). The micro morphology and structure of the composite flocculant were characterized with SEM and IR. The effect of the CS/ATP composite flocculant on the recovery of the main components from the bezafibrate (BZ) wastewater of a pharmaceutical plant was investigated. The influences of the flocculation temperature, mixing time and standing time on the flocculation effect were investigated by determining the BZ content of the recovered crude products as the evaluation index so as to obtain the best recovery process. The experimental results show that the best flocculation condition is created when we add 20 mg/mL of CS/ATP to the waste liquid, stir it at 30 °C for 10 min and allow it to stand for 30 min. Compared with the traditional recovery process, the BZ content of the recovered crude products can be increased from 47 % to 74 % when using the CS/ATP composite flocculant. This flocculant can effectively overcome the defects of single material residues and difficult separation, accelerate the settlement of impurities in a waste liquid effectively, and can be used in the field of solution clearing and waste liquid separation.
{"title":"PREPARATION AND APPLICATION OF CHITOSAN/ATTAPULGITE COMPOSITE FLOCCULANT","authors":"Y. Zhong, Jie Wu, Su-Zhen Wang, S. Tang","doi":"10.17222/mit.2022.456","DOIUrl":"https://doi.org/10.17222/mit.2022.456","url":null,"abstract":"A chitosan/attapulgite (CS/ATP) composite flocculant with excellent adsorption was prepared from chitosan (CS) and attapulgite clay (ATP). The micro morphology and structure of the composite flocculant were characterized with SEM and IR. The effect of the CS/ATP composite flocculant on the recovery of the main components from the bezafibrate (BZ) wastewater of a pharmaceutical plant was investigated. The influences of the flocculation temperature, mixing time and standing time on the flocculation effect were investigated by determining the BZ content of the recovered crude products as the evaluation index so as to obtain the best recovery process. The experimental results show that the best flocculation condition is created when we add 20 mg/mL of CS/ATP to the waste liquid, stir it at 30 °C for 10 min and allow it to stand for 30 min. Compared with the traditional recovery process, the BZ content of the recovered crude products can be increased from 47 % to 74 % when using the CS/ATP composite flocculant. This flocculant can effectively overcome the defects of single material residues and difficult separation, accelerate the settlement of impurities in a waste liquid effectively, and can be used in the field of solution clearing and waste liquid separation.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"57 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76926302","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}
Waste tyre-rubber disposal is a serious global problem, posing a severe danger to the environment. This present study aims to investigate the performance of concrete utilizing recycled tyre-rubber waste as a partial replacement for natural fine aggregate. Three different sizes of crumb rubber were combined to produce a well-graded sample. Based on various trials, mixed proportions of M30 grade concrete and the crumb rubber replacement percentages were determined. The test specimens were prepared. Experimental investigations have been carried out to study the mechanical, durability and temperature properties of the developed Crumb rubber concrete (CRC). In this study, crumb rubber replaced the fine aggregate in various percentages, such as (0, 5, 7.5, 10 and 15) %. Microstructural analysis was also carried out with EDX and scanning electron microscopy (SEM) to visualize the performance of rubber with CSH gel under different temperature conditions. The study found that (CRC5) a 5 % replacement of crumb rubber is the optimum percentage to replace the natural fine aggregate to develop the crumb rubber concrete. The durability tests concluded that the proposed model of rubberized concrete is suitable for any structural elements exposed to acidic environmental conditions.
{"title":"EXPERIMENTAL INVESTIGATION OF CONCRETE WITH RECYCLED TYRE-RUBBER WASTE AS FINE AGGREGATE MATERIAL","authors":"Renuka Senthil Muthalvan, Mervin Sanjith Innocent Prasanna","doi":"10.17222/mit.2022.585","DOIUrl":"https://doi.org/10.17222/mit.2022.585","url":null,"abstract":"Waste tyre-rubber disposal is a serious global problem, posing a severe danger to the environment. This present study aims to investigate the performance of concrete utilizing recycled tyre-rubber waste as a partial replacement for natural fine aggregate. Three different sizes of crumb rubber were combined to produce a well-graded sample. Based on various trials, mixed proportions of M30 grade concrete and the crumb rubber replacement percentages were determined. The test specimens were prepared. Experimental investigations have been carried out to study the mechanical, durability and temperature properties of the developed Crumb rubber concrete (CRC). In this study, crumb rubber replaced the fine aggregate in various percentages, such as (0, 5, 7.5, 10 and 15) %. Microstructural analysis was also carried out with EDX and scanning electron microscopy (SEM) to visualize the performance of rubber with CSH gel under different temperature conditions. The study found that (CRC5) a 5 % replacement of crumb rubber is the optimum percentage to replace the natural fine aggregate to develop the crumb rubber concrete. The durability tests concluded that the proposed model of rubberized concrete is suitable for any structural elements exposed to acidic environmental conditions.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90710679","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：