Pub Date : 2023-06-28DOI: 10.52923/vmfs.jstm.62023.108.02
Xuan Tran Thi, Toai Vu Dinh
Residual stress and welding deformation are unfavorable factors and always exist in the welded joint. They seriously reduce the working capacity of the welded structure, and at the same time disfigure the aesthetics of the welded structure. Therefore, knowing the influence of the welding parameter, specifically the heat-input, on the residual stress and deformation of the welded joint is of great significance, helping to determine the appropriate welding parameter for each specific welding joint. Welding deformation can be easily measured with common measuring instruments, but determining the residual stress in the welded joint by experiment encounters many difficulties, especially in the interior of the material, so this study proposes a solution to determine the residual stress as well as welding deformation by numerical simulation using SYSWELD software with the least cost and fastest time. The research results show that when welding with a higher heat-input, the residual stress in the welded joint will be greater, causing the longitudinal and transverse deformations to be larger. For a butt welding joint made of structural carbon steel A516 grade 70 with 16 mm thickness, it is necessary to weld 4 passes with the heat-input respectively for the minimum residual stress and deformation are q1=2252 J/mm, q2=2828 J/mm, q3=2458 J/mm, and q4=2878 J/mm. The post-weld heat treatment immediately after welding at 595 oC for 40 minutes will reduce residual stress 3.45 times, reduce longitudinal deformation 2.82 times, reduce transverse deformation 1.54 times, and reduce the angular deformation 1.32 times.
{"title":"Effect of heat-input and post-weld heat treatment on residual stress and deformation of butt welded joint made by structural carbon steel A516 grade 70","authors":"Xuan Tran Thi, Toai Vu Dinh","doi":"10.52923/vmfs.jstm.62023.108.02","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.62023.108.02","url":null,"abstract":"Residual stress and welding deformation are unfavorable factors and always exist in the welded joint. They seriously reduce the working capacity of the welded structure, and at the same time disfigure the aesthetics of the welded structure. Therefore, knowing the influence of the welding parameter, specifically the heat-input, on the residual stress and deformation of the welded joint is of great significance, helping to determine the appropriate welding parameter for each specific welding joint. Welding deformation can be easily measured with common measuring instruments, but determining the residual stress in the welded joint by experiment encounters many difficulties, especially in the interior of the material, so this study proposes a solution to determine the residual stress as well as welding deformation by numerical simulation using SYSWELD software with the least cost and fastest time. The research results show that when welding with a higher heat-input, the residual stress in the welded joint will be greater, causing the longitudinal and transverse deformations to be larger. For a butt welding joint made of structural carbon steel A516 grade 70 with 16 mm thickness, it is necessary to weld 4 passes with the heat-input respectively for the minimum residual stress and deformation are q1=2252 J/mm, q2=2828 J/mm, q3=2458 J/mm, and q4=2878 J/mm. The post-weld heat treatment immediately after welding at 595 oC for 40 minutes will reduce residual stress 3.45 times, reduce longitudinal deformation 2.82 times, reduce transverse deformation 1.54 times, and reduce the angular deformation 1.32 times.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135359809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.52923/vmfs.jstm.62023.108.01
Tan Ha Minh, Khanh Pham Mai
The mechanical properties of alloys and castings strongly depend on the formation of their microstructure. Heat treatment conditions have a directly effect on the grain size. Typically, smaller grain sizes result in improved mechanical properties. To achieve small grain sizes, a commonly applied method is rapid cooling, known as quenching. During the cooling process, there is always a temperature gradient within the casting, which can affect the formation of the microstructure. This study investigates the influence of temperature gradient on the size and morphology of the grains. The results show that at lower temperature gradients, the formed microstructure has a spherical shape. Increasing the temperature gradient leads to greater grain deformation.
{"title":"Effects of temperature gradient on precipitation in liquid Si-Ti-C","authors":"Tan Ha Minh, Khanh Pham Mai","doi":"10.52923/vmfs.jstm.62023.108.01","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.62023.108.01","url":null,"abstract":"The mechanical properties of alloys and castings strongly depend on the formation of their microstructure. Heat treatment conditions have a directly effect on the grain size. Typically, smaller grain sizes result in improved mechanical properties. To achieve small grain sizes, a commonly applied method is rapid cooling, known as quenching. During the cooling process, there is always a temperature gradient within the casting, which can affect the formation of the microstructure. This study investigates the influence of temperature gradient on the size and morphology of the grains. The results show that at lower temperature gradients, the formed microstructure has a spherical shape. Increasing the temperature gradient leads to greater grain deformation.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135359808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.52923/vmfs.jstm.42023.107.02
Hai Nguyen Hong, Tan Ha Minh, Trung Nguyen Danh
Manganese steels have been widely used in industries due to their good wear resistance, high work hardening ability, and high toughness and ductility. This research investigated the effect of modification, i.e., FeTi and Mischmetal, on the grain size and mechanical properties of the high manganese steel (13–15 wt.%). The alloys are modified at different temperatures of 1500, 1550, and 1600 o. The modified alloys were heat-treated after solidification by a two-step process. The grain size, chemical composition, and phase formation of the heat-treated steel were characterized by Optical Microscopy, X-ray Diffractometry, and Energy-Dispersive X-ray Spectroscopy. The mechanical properties of the steel, such as Brinell hardness, tensile strength, and toughness, were measured. As a result, the grain size of the heat-treated alloys is smaller compared to that of un-modified alloys and decreases with the increase in modification amount. The addition of Ti reduced C in the austenite phase by forming very stable carbides, TiC. Maximum tensile strength of 780 MPa was achieved with the addition of 0.1 wt.% Ti, while maximum fracture toughness was 140 J/cm2 at 0.05 wt.% Ti.
{"title":"Effects of titanium addition on austenite grain size and mechanical properties of high manganese steel","authors":"Hai Nguyen Hong, Tan Ha Minh, Trung Nguyen Danh","doi":"10.52923/vmfs.jstm.42023.107.02","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.42023.107.02","url":null,"abstract":"Manganese steels have been widely used in industries due to their good wear resistance, high work hardening ability, and high toughness and ductility. This research investigated the effect of modification, i.e., FeTi and Mischmetal, on the grain size and mechanical properties of the high manganese steel (13–15 wt.%). The alloys are modified at different temperatures of 1500, 1550, and 1600 o. The modified alloys were heat-treated after solidification by a two-step process. The grain size, chemical composition, and phase formation of the heat-treated steel were characterized by Optical Microscopy, X-ray Diffractometry, and Energy-Dispersive X-ray Spectroscopy. The mechanical properties of the steel, such as Brinell hardness, tensile strength, and toughness, were measured. As a result, the grain size of the heat-treated alloys is smaller compared to that of un-modified alloys and decreases with the increase in modification amount. The addition of Ti reduced C in the austenite phase by forming very stable carbides, TiC. Maximum tensile strength of 780 MPa was achieved with the addition of 0.1 wt.% Ti, while maximum fracture toughness was 140 J/cm2 at 0.05 wt.% Ti.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136084508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.52923/vmfs.jstm.42023.107.01
Trang Ha Kieu, Thuong Le Thi, Trang Nguyen Thi, Nga Nguyen Kim, Quan Ngo Duc, Dien Luong Xuan
A green sol-gel method was employed to synthesize TiO2 nanoparticles (NPs) using titanium metal. The syn-thesized TiO2 NPs underwent comprehensive characterization using techniques including X-ray diffraction (XRD), infrared spectroscopy (IR), transmission electron microscopy (TEM), and UV–Vis diffuse reflectance spectroscopy (UV-Vis DRS) to evaluate their structure, morphology, and spectral properties. By adjusting the amount of oxalic acid, tailored physico-chemical properties of anatase TiO2 catalysts were achieved. The obtained TiO2 catalysts demonstrated a high surface area, excellent absorption, and remarkable photocatalytic degradation of methylene blue under visible light irradiation. This enhancement is primarily contributed by the large surface area and oxygen vacancies.
{"title":"Facile synthesis of anatase TiO2 nanoparticles using titanium metal and its enhanced photocatalytic activity under visible light","authors":"Trang Ha Kieu, Thuong Le Thi, Trang Nguyen Thi, Nga Nguyen Kim, Quan Ngo Duc, Dien Luong Xuan","doi":"10.52923/vmfs.jstm.42023.107.01","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.42023.107.01","url":null,"abstract":"A green sol-gel method was employed to synthesize TiO2 nanoparticles (NPs) using titanium metal. The syn-thesized TiO2 NPs underwent comprehensive characterization using techniques including X-ray diffraction (XRD), infrared spectroscopy (IR), transmission electron microscopy (TEM), and UV–Vis diffuse reflectance spectroscopy (UV-Vis DRS) to evaluate their structure, morphology, and spectral properties. By adjusting the amount of oxalic acid, tailored physico-chemical properties of anatase TiO2 catalysts were achieved. The obtained TiO2 catalysts demonstrated a high surface area, excellent absorption, and remarkable photocatalytic degradation of methylene blue under visible light irradiation. This enhancement is primarily contributed by the large surface area and oxygen vacancies.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"312 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136084629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.52923/vmfs.jstm.42023.107.03
Anh Le Thi Van, Ngoc Tran Vu Diem, Thao Nguyen Thi
In this study, the titanium dioxide was synthesized from ilmenite ore concentrate (containing 80,48 % TiO2; 9,65 % SiO2; 4,84 % ZrO2; 1,36 % Fe2O3,...) using the molten alkali method. The alkali roasting process was investigated under various conditions: NaOH/ilmenite mass ratio (0.9 - 1.2), reaction temperature from 500 to 650 oC for 60 minutes. These experimental results showed that the highest roasting efficiency was 95 % when NaOH/ilmenite ratio was 1,1/1,0 at a temperature of 550 oC for 60 minutes. The roasted product was then leached in water to form H2TiO3 solid and remove soluble impurities. The solid was further leached in HCl acid under different conditions: acid concentration (10 - 25 %), temperature (25 - 80 oC), time (45 - 90 minutes). The highest leaching efficiency of 97 % was achieved under the condition of 20 % acid concentration at a temperature of 60 oC for 60 minutes. At the end of the process, the leached solution was hydrolyzed at 100 oC, resulting in a precipitate that was calcined at 900 oC for 120 minutes, producing a product with 92 % TiO2.
{"title":"Synthesis of TiO2 from Ilmenite ore using the molten salt method","authors":"Anh Le Thi Van, Ngoc Tran Vu Diem, Thao Nguyen Thi","doi":"10.52923/vmfs.jstm.42023.107.03","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.42023.107.03","url":null,"abstract":"In this study, the titanium dioxide was synthesized from ilmenite ore concentrate (containing 80,48 % TiO2; 9,65 % SiO2; 4,84 % ZrO2; 1,36 % Fe2O3,...) using the molten alkali method. The alkali roasting process was investigated under various conditions: NaOH/ilmenite mass ratio (0.9 - 1.2), reaction temperature from 500 to 650 oC for 60 minutes. These experimental results showed that the highest roasting efficiency was 95 % when NaOH/ilmenite ratio was 1,1/1,0 at a temperature of 550 oC for 60 minutes. The roasted product was then leached in water to form H2TiO3 solid and remove soluble impurities. The solid was further leached in HCl acid under different conditions: acid concentration (10 - 25 %), temperature (25 - 80 oC), time (45 - 90 minutes). The highest leaching efficiency of 97 % was achieved under the condition of 20 % acid concentration at a temperature of 60 oC for 60 minutes. At the end of the process, the leached solution was hydrolyzed at 100 oC, resulting in a precipitate that was calcined at 900 oC for 120 minutes, producing a product with 92 % TiO2.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136084630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.52923/vmfs.jstm.22023.106.02
Long Bui Duc, Thang Le Hong, Khanh Dang Quoc, Bang Le Thi, Dinh Le Cong
Alumium (Al) – based materials are highly demanded for automobiles, transportation, and aerospace etc. In this research, Al – based TiC composites were fabricated using powder metallurgy (P/M) technology from Al, Cu, and TiC powders with the compositions of Al – 5 wt.% TiC, and Al – 5 Cu/ 5wt.% TiC. The composite powders were well mixed and compacted using cold pressing technique with an applied pressure of 500 MPa. The compacted samples were sintered at 550 oC in Ar atmosphere for 1 h. The distribution of TiC particles in the Al matrix was observed using scanning electron microscopy (SEM). The phase formation of sintered composite was characterized using Xray diffraction (XRD). The results showed that TiC particles homogeneously distributed in the Al matrix. The density of Al -5 wt.%TiC and Al – 5 Cu/ 5 wt.%TiC composites achieved 96.7 and 98.0 % of theoretical density, respectively. The microhardness of pure Al increases from 27 HV to » 38 HV when reinforcing with 5 wt.% TiC, whilst that of the Al – 5TiC composite increase to » 55 Hv when alloying with 5 wt.% Cu.
{"title":"Enhanced microhardness of Al – 5 wt.% TiC composite by alloying with Cu","authors":"Long Bui Duc, Thang Le Hong, Khanh Dang Quoc, Bang Le Thi, Dinh Le Cong","doi":"10.52923/vmfs.jstm.22023.106.02","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.22023.106.02","url":null,"abstract":"Alumium (Al) – based materials are highly demanded for automobiles, transportation, and aerospace etc. In this research, Al – based TiC composites were fabricated using powder metallurgy (P/M) technology from Al, Cu, and TiC powders with the compositions of Al – 5 wt.% TiC, and Al – 5 Cu/ 5wt.% TiC. The composite powders were well mixed and compacted using cold pressing technique with an applied pressure of 500 MPa. The compacted samples were sintered at 550 oC in Ar atmosphere for 1 h. The distribution of TiC particles in the Al matrix was observed using scanning electron microscopy (SEM). The phase formation of sintered composite was characterized using Xray diffraction (XRD). The results showed that TiC particles homogeneously distributed in the Al matrix. The density of Al -5 wt.%TiC and Al – 5 Cu/ 5 wt.%TiC composites achieved 96.7 and 98.0 % of theoretical density, respectively. The microhardness of pure Al increases from 27 HV to » 38 HV when reinforcing with 5 wt.% TiC, whilst that of the Al – 5TiC composite increase to » 55 Hv when alloying with 5 wt.% Cu.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135828050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.52923/vmfs.jstm.22023.106.01
Quyen Hoang Thi Ngoc, Khanh Pham Mai
A 27 wt. % Cr white cast iron has been subjected to various austenitization heat treatments. The transformation of the matrix phase as well as the precipitation of secondary carbides at the austenitization temperature have been clearly determined in this paper. The results showed that secondary carbides precipitated along the defect sites of the austenitic phase at 900 oC during the austenitization. They grew up within austenit matrix, and there exist some retained austenit. The amount and size of secondary carbides increase as the austenitization temperature rises to 1000 oC. At 1050 oC/3 h, the size of secondary carbides reduces significantly with a high distribution density in the matrix phase. Higher austenitization temperatures cause the matrix to become more stable and make it more difficult to produce secondary carbides, as well as increase the number of defects in the matrix. The microhardness of the austenit matrix is affected a lot by how many and how big the secondary carbide particles are. At 1050 oC/3 h, the micro-hardness is the highest one. When the temperature of austenitization goes above 1050 oC, the micro-hardness of the matrix reduces.
{"title":"https://www.jstmetal.com/2023/06/anh-huong-cua-nhiet-do-austenit-hoa-den-qua-trinh-tiet-pha-cacbit-thu-cap-cua-gang-trang-27-crom/","authors":"Quyen Hoang Thi Ngoc, Khanh Pham Mai","doi":"10.52923/vmfs.jstm.22023.106.01","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.22023.106.01","url":null,"abstract":"A 27 wt. % Cr white cast iron has been subjected to various austenitization heat treatments. The transformation of the matrix phase as well as the precipitation of secondary carbides at the austenitization temperature have been clearly determined in this paper. The results showed that secondary carbides precipitated along the defect sites of the austenitic phase at 900 oC during the austenitization. They grew up within austenit matrix, and there exist some retained austenit. The amount and size of secondary carbides increase as the austenitization temperature rises to 1000 oC. At 1050 oC/3 h, the size of secondary carbides reduces significantly with a high distribution density in the matrix phase. Higher austenitization temperatures cause the matrix to become more stable and make it more difficult to produce secondary carbides, as well as increase the number of defects in the matrix. The microhardness of the austenit matrix is affected a lot by how many and how big the secondary carbide particles are. At 1050 oC/3 h, the micro-hardness is the highest one. When the temperature of austenitization goes above 1050 oC, the micro-hardness of the matrix reduces.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135827148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.52923/vmfs.jstm.22023.106.03
Tan Ha Minh, Khanh Pham Mai, Hai Nguyen Hong
The lost foam casting process utilizes polymeric foam patterns to produce the metallic components. Foamed polymer patterns are coated with a refractory slury, dried and embedded in unbonded sand. Molten metal is poured directly on the coated polymer. The polymer is thermally decomposed and is gradually replaced by the liquid metal to create the casting after solidification. Expanded polystyrene (EPS) is the most common pattern material used in commercial practice. In this paper, experiments are conducted to examine the filling of an aluminum alloy melt into the molds. The purpose is to observe some parameters such as the gate cross-section area, vaccum pressure, gas gap length, metal pouring temperature in lost foam casting of aluminum. The results indicate that the gate section, metal pouring temperature and vaccum pressure affect directly the mold-filling time.
{"title":"Effects of gate cross-section area and vaccum pressure on mold filling in lost foam casting","authors":"Tan Ha Minh, Khanh Pham Mai, Hai Nguyen Hong","doi":"10.52923/vmfs.jstm.22023.106.03","DOIUrl":"https://doi.org/10.52923/vmfs.jstm.22023.106.03","url":null,"abstract":"The lost foam casting process utilizes polymeric foam patterns to produce the metallic components. Foamed polymer patterns are coated with a refractory slury, dried and embedded in unbonded sand. Molten metal is poured directly on the coated polymer. The polymer is thermally decomposed and is gradually replaced by the liquid metal to create the casting after solidification. Expanded polystyrene (EPS) is the most common pattern material used in commercial practice. In this paper, experiments are conducted to examine the filling of an aluminum alloy melt into the molds. The purpose is to observe some parameters such as the gate cross-section area, vaccum pressure, gas gap length, metal pouring temperature in lost foam casting of aluminum. The results indicate that the gate section, metal pouring temperature and vaccum pressure affect directly the mold-filling time.","PeriodicalId":485321,"journal":{"name":"Tạp chí Khoa học Công nghệ Kim loại","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135827147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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