Pub Date : 2021-06-17DOI: 10.4236/OJMETAL.2021.112002
M. S. El-Deeb, K. Ibrahim, S. S. Mohamed, R. Elshaer
In the present work, titanium alloy with a composition of Ti-6.5Al-3Mo-1.9Nb-2.2Sn-2.2Zr-1.5Cr (TC21) was subjected to plastic deformation and aging processes. A Plastic deformation at room temperature with 2%, 3% and 4% stroke strain was applied on the studied samples. Then, the samples aged at 575°C for 4 hr. By applying different plastic deformation ratios, the structure revealed an elongated and thin β-phase embedded in an α-phase. Secondary α-platelets were precipitated in the residual β-phase. Maximum hardness (HV440) was obtained for 4% deformed + aged samples. Minimum hardness (HV320) was recorded for the as-cast samples without deformation. The highest ultimate tensile strength of 1311 MPa was obtained for 4% deformed + aged samples due to presence of high amount of dislocation density as well as precipitation of secondary α-platelets in the residual β-phase. The lowest ultimate tensile strength of 1020 MPa was reported for as-cast samples. Maximum elongation of 14% was registered for 4% deformed + aged samples and minimum one of 3% was obtained for as-cast samples. Hence, strain hardening + aging can enhance considerably the elongation of TC21 Ti-alloy up to 366% and 133% in case of applying 4% deformation + aged compared to as-cast and aged samples without applying plastic deformation, respectively.
{"title":"Influence of Plastic Deformation and Aging Process on Microstructure and Tensile Properties of Cast Ti-6Al-2Sn-2Zr-2Mo-1.5Cr-2Nb-0.1Si Alloy","authors":"M. S. El-Deeb, K. Ibrahim, S. S. Mohamed, R. Elshaer","doi":"10.4236/OJMETAL.2021.112002","DOIUrl":"https://doi.org/10.4236/OJMETAL.2021.112002","url":null,"abstract":"In the present work, titanium alloy with a composition of \u0000Ti-6.5Al-3Mo-1.9Nb-2.2Sn-2.2Zr-1.5Cr (TC21) was subjected to plastic deformation and aging processes. A Plastic deformation at room temperature with 2%, 3% and 4% stroke strain was applied on the studied samples. Then, the samples aged at 575°C for 4 hr. By applying different plastic deformation ratios, the structure revealed an elongated and thin β-phase embedded in an α-phase. Secondary α-platelets were precipitated in the residual β-phase. Maximum hardness (HV440) was obtained for 4% deformed + aged samples. Minimum hardness (HV320) was recorded for the as-cast samples without deformation. The highest ultimate tensile strength of 1311 MPa was obtained for 4% deformed + aged samples due to presence of high amount of dislocation density as well as precipitation of secondary α-platelets in the residual β-phase. The lowest ultimate tensile strength of 1020 MPa was reported for as-cast samples. Maximum elongation of 14% was registered for 4% deformed + aged samples and minimum one of 3% was obtained for as-cast samples. Hence, strain hardening + aging can enhance considerably the elongation of TC21 Ti-alloy up to 366% and 133% in case of applying 4% deformation + aged compared to as-cast and aged samples without applying plastic deformation, respectively.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128871255","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 : 2020-06-30DOI: 10.4236/ojmetal.2020.102002
A. Benhmid, K. E. Ttaib, K. Edbey, V. N. Kalevaru, B. Lücke
Interactions between metals and supports are of fundamental interest in heterogeneous catalysis, Noble metal particles supported on transition metal oxides (TMO) may undergo a so-called strong metal-support interaction via encapsulation. This perspective addresses catalytic properties of the metal catalysts in the SMSI state which can be explained on the basis of complementary studies. The electronic geometric and bifunctional effects originating from strong metal-support interactions (SMSI) that are responsible for the catalyst’s activity, selectivity, and stability are key factors that determine performance. A series of Pd-Sb supported on different metal oxide (i.e. SiO2, γ-Al2O3, TiO2, and ZrO2) were prepared by the impregnation method. The catalysts were characterized by N2 adsorption (BET-SA and pore size distribution), TEM (transmission electron microscope), TPR (temperature-programmed reduction), CO-chemisorption, the structural characterization of Pd (dispersity, surface area), interaction between Pd and Sb2O3 and also the influence of the nature of the support were investigated. SiO2 supported Pd catalyst exhibited the highest surface area (192.6 m2/g) and pore volume (0.542 cm3/g) compared to the other supported oxides catalysts. The electron micrographs of these catalysts showed a narrow size particle distribution of Pd, but with varying sizes which in the range from 1 to 10 nm, depending on the type of support used. The results show almost completely suppressed of CO chemisorption when the catalysts were subjected to high temperature reduction (HTR), this suppression was overcome by oxidation of a reduced Pd/MeOx catalysts followed by re-reduction in hydrogen at 453 K low temperature reduction (LTR), almost completely restored the normal chemisorptive properties of the catalysts, this suppression was attributed by SbOx species by a typical SMSI effect as known for other reducible supports such as TiO2, ZrO2, CeO2, and Nb2O5.
{"title":"A New Type of Strong Metal-Support Interaction Caused by Antimony Species","authors":"A. Benhmid, K. E. Ttaib, K. Edbey, V. N. Kalevaru, B. Lücke","doi":"10.4236/ojmetal.2020.102002","DOIUrl":"https://doi.org/10.4236/ojmetal.2020.102002","url":null,"abstract":"Interactions between metals and supports are of fundamental interest in heterogeneous catalysis, Noble metal particles supported on transition metal oxides (TMO) may undergo a so-called strong metal-support interaction via encapsulation. This perspective addresses catalytic properties of the metal catalysts in the SMSI state which can be explained on the basis of complementary studies. The electronic geometric and bifunctional effects originating from strong metal-support interactions (SMSI) that are responsible for the catalyst’s activity, selectivity, and stability are key factors that determine performance. A series of Pd-Sb supported on different metal oxide (i.e. SiO2, γ-Al2O3, TiO2, and ZrO2) were prepared by the impregnation method. The catalysts were characterized by N2 adsorption (BET-SA and pore size distribution), TEM (transmission electron microscope), TPR (temperature-programmed reduction), CO-chemisorption, the structural characterization of Pd (dispersity, surface area), interaction between Pd and Sb2O3 and also the influence of the nature of the support were investigated. SiO2 supported Pd catalyst exhibited the highest surface area (192.6 m2/g) and pore volume (0.542 cm3/g) compared to the other supported oxides catalysts. The electron micrographs of these catalysts showed a narrow size particle distribution of Pd, but with varying sizes which in the range from 1 to 10 nm, depending on the type of support used. The results show almost completely suppressed of CO chemisorption when the catalysts were subjected to high temperature reduction (HTR), this suppression was overcome by oxidation of a reduced Pd/MeOx catalysts followed by re-reduction in hydrogen at 453 K low temperature reduction (LTR), almost completely restored the normal chemisorptive properties of the catalysts, this suppression was attributed by SbOx species by a typical SMSI effect as known for other reducible supports such as TiO2, ZrO2, CeO2, and Nb2O5.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125427299","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 : 2020-03-18DOI: 10.4236/ojmetal.2020.101001
B. Borts, S. Skoromnaya, Viktor Ivanovich Tkachenко
Separation of molybdenum isotope complexes by supercritical fluid extraction (SFE) with carbon dioxide was studied experimentally. The extraction of molybdenum isotope complexes was carried out in the updated extraction chamber (reactor) of the SFE-U installation, which provided an initial pressure of P ≤ 20 MPa at constant temperatures of the upper T1 = 35°C and bottom T2 = 45°C flanges. The device, through which the eluent was discharged, involved a set of four thin tubes of different lengths located inside the reactor. The axes of the tubes and the reactor are parallel and the tubes are equally spaced circumferentially inside the reactor. The extract was removed from each tube through channels isolated from each other and located in the bottom flange with cylindrical expansion, in which several layers of filter paper were placed. After passing through the filters the extract entered a restrictor designed to remove the eluent from the reactor. The initial pressure of carbon dioxide and the holding time of the extract were specified in the experiments. The level of the eluent sampling was set by the lengths of the tubes depending on the reactor height. A method of producing molybdenum complexes was described. It was experimentally shown that at an initial pressure of 20 MPa and a given holding time a difference from the natural content of Mo isotopes for given heights of extract sampling depending on the reactor height was observed in extracts removed through filters. The ranges of deviation of the content of molybdenum isotopes in extracts from natural one were determined.
{"title":"Separation of Molybdenum Isotopes at Supercritical Fluid Extraction with Carbon Dioxide in a Vertical Gradient Field of Temperatures","authors":"B. Borts, S. Skoromnaya, Viktor Ivanovich Tkachenко","doi":"10.4236/ojmetal.2020.101001","DOIUrl":"https://doi.org/10.4236/ojmetal.2020.101001","url":null,"abstract":"Separation of molybdenum isotope complexes by \u0000supercritical fluid extraction (SFE) with carbon dioxide was studied \u0000experimentally. The extraction of molybdenum isotope complexes was carried out \u0000in the updated extraction chamber (reactor) of the SFE-U \u0000installation, which provided an initial pressure of P ≤ 20 MPa at constant temperatures of the upper T1 = 35°C and bottom T2 = 45°C flanges. The device, through which the \u0000eluent was discharged, involved a set of four thin tubes of different lengths \u0000located inside the reactor. The axes \u0000of the tubes and the reactor are parallel and the tubes are equally spaced \u0000circumferentially inside the reactor. The extract was removed from each tube \u0000through channels isolated from each other and located in the bottom flange with \u0000cylindrical expansion, in which several layers of filter paper were placed. \u0000After passing through the filters the extract entered a restrictor designed to \u0000remove the eluent from the reactor. The initial pressure of carbon dioxide and \u0000the holding time of the extract were specified in the experiments. The level of \u0000the eluent sampling was set by the lengths of the tubes depending on the \u0000reactor height. A method of producing molybdenum complexes was described. It \u0000was experimentally shown that at an initial pressure of 20 MPa and a given \u0000holding time a difference from the natural content of Mo isotopes for given \u0000heights of extract sampling depending on the reactor height was observed in \u0000extracts removed through filters. The ranges of deviation of the content of \u0000molybdenum isotopes in extracts from natural one were determined.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120940520","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 : 2019-12-30DOI: 10.4236/ojmetal.2019.94004
P. Dipak, D. C. Tiwari, S. Dwivedi
The microwave absorption properties of polymer composite PANI/PVA/NiFe2O3 are investigated. The polymer composites of PANI/PVA and NiFe2O3 are prepared in two steps. NiFe2O3 is synthesized by modified sol gel method and PANI by chemical polymerization method. Microwave absorption parameters of polymer composite are measured at X-band. The microwave absorption is found to be -28 dB (99%) at 10.2 GHz. Different characterization techniques such as SEM-EDX, FTIR and XRD are done. The SEM result shows flakes like structure for PANI/PVA and crystalline structure for NiFe2O3. FTIR of the composite reveals the interaction between the PANI/PVA and NiFe2O3.
{"title":"Synthesis of Polymer Blend Ferrite Composite for Microwave Absorption at X-Band Frequency","authors":"P. Dipak, D. C. Tiwari, S. Dwivedi","doi":"10.4236/ojmetal.2019.94004","DOIUrl":"https://doi.org/10.4236/ojmetal.2019.94004","url":null,"abstract":"The microwave absorption properties of polymer \u0000composite PANI/PVA/NiFe2O3 are investigated. The polymer composites of PANI/PVA and NiFe2O3 are prepared in two steps. NiFe2O3 is synthesized by \u0000modified sol gel method and PANI by chemical polymerization method. Microwave \u0000absorption parameters of polymer composite are measured at X-band. The \u0000microwave absorption is found to be -28 dB \u0000(99%) at 10.2 GHz. Different characterization techniques such as \u0000SEM-EDX, FTIR and XRD are done. The SEM result shows flakes like structure for \u0000PANI/PVA and crystalline structure for NiFe2O3. FTIR of \u0000the composite reveals the interaction between the PANI/PVA and NiFe2O3.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129255330","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 : 2019-09-30DOI: 10.4236/ojmetal.2019.93003
M. Faye, F. Sambe, M. Dieng, A. Toure, Matar Faye, C. Diop
In the present work, the treatment of synthetic waters doped with iron (II) has been studied. The treatment mechanism used in this study is the biological oxidation which consists, in test tubes, of bringing bacteria isolated on Petri dishes into contact with water containing divalent iron (II). These de-ironing bacteria (non-specific bacteria) are used to carry out laboratory biological oxidation experiments on iron (II) under different pH conditions (pH = 3.4 - 3.6, pH = 7.3 - 7.5 and pH = 9.8 - 10) and variable concentration of iron (II). Biological treatment trials included different concentrations of iron during time intervals of a day. Examination of the elimination kinetics of Iron (II) indicates a removal rate of 59.453% for an initial iron concentration in the synthetic solution of 1 mg·L−1 at basic pH (pH = 9.8 - 10). Therefore, the degradation of divalent iron by this method seems to be quite effective, but it should be noted that biological nitrification is impaired by the presence of high iron concentrations above 5 mg·L−1.
{"title":"Isolation of Iron Bacteria from Washing Sludge Filters Kolda (Senegal) Water Treatment Station and Study of the Kinetics of Biological Degradation of the Iron (II)","authors":"M. Faye, F. Sambe, M. Dieng, A. Toure, Matar Faye, C. Diop","doi":"10.4236/ojmetal.2019.93003","DOIUrl":"https://doi.org/10.4236/ojmetal.2019.93003","url":null,"abstract":"In the present work, the treatment of synthetic waters doped with iron (II) has been studied. The treatment mechanism used in this study is the biological oxidation which consists, in test tubes, of bringing bacteria isolated on Petri dishes into contact with water containing divalent iron (II). These de-ironing bacteria (non-specific bacteria) are used to carry out laboratory biological oxidation experiments on iron (II) under different pH conditions (pH = 3.4 - 3.6, pH = 7.3 - 7.5 and pH = 9.8 - 10) and variable concentration of iron (II). Biological treatment trials included different concentrations of iron during time intervals of a day. Examination of the elimination kinetics of Iron (II) indicates a removal rate of 59.453% for an initial iron concentration in the synthetic solution of 1 mg·L−1 at basic pH (pH = 9.8 - 10). Therefore, the degradation of divalent iron by this method seems to be quite effective, but it should be noted that biological nitrification is impaired by the presence of high iron concentrations above 5 mg·L−1.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128430438","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 : 2019-06-30DOI: 10.4236/OJMETAL.2019.92002
R. Elshaer, K. Ibrahim, A. Barakat, R. Abbas
TC21 is considered a new titanium alloy that is used in aircraft applications as a replacement for the famous Ti-6Al-4V alloy due to its high strength. The effect of single and duplex stage heat treatments on fatigue behavior of TC21 Ti-alloy (Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-0.09Si, wt.%) was investigated. Two heat treatment cycles were applied on as-received TC21 Ti-alloy. The first cycle was called single stage heat treatment (SSHT). The other cycle was named duplex stage heat treatment (DSHT). Typical microstructures of SSHT & DSHT composed of primary equiaxed α phase, residual β phase and secondary α phase (αs). Secondary α phase was precipitated in the residual β phase due to low cooling rate using air cooling and aging treatment. Morphology of α phase does not change after solution treatments, while their volume fraction and grain size were changed. SSHT showed the highest fatigue strength of 868 MPa due to high tensile strength, hardness and existing of high percentages of residual β phase in the microstructure. However, DSHT reported lower fatigue strength of 743 MPa due to increasing grain size of α phase. The fracture surface of fatigue samples showed cleavage ductile fracture mode for both heat treatment cycles.
{"title":"Fatigue Performance of Heat Treated TC21 Ti-Alloy","authors":"R. Elshaer, K. Ibrahim, A. Barakat, R. Abbas","doi":"10.4236/OJMETAL.2019.92002","DOIUrl":"https://doi.org/10.4236/OJMETAL.2019.92002","url":null,"abstract":"TC21 is \u0000considered a new titanium alloy that is used in aircraft applications as a \u0000replacement for the famous Ti-6Al-4V alloy due to its high strength. The effect \u0000of single and duplex stage heat treatments on fatigue behavior of TC21 Ti-alloy \u0000(Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-0.09Si, wt.%) was investigated. Two heat treatment \u0000cycles were applied on as-received TC21 Ti-alloy. The first cycle was called \u0000single stage heat treatment (SSHT). The other cycle was named duplex stage heat \u0000treatment (DSHT). Typical microstructures of SSHT & DSHT composed of \u0000primary equiaxed α phase, residual β phase and secondary α phase (αs). Secondary α phase was precipitated in the residual β phase due to low cooling rate using air cooling and aging treatment. \u0000Morphology of α phase does not change after solution treatments, while their volume \u0000fraction and grain size were changed. SSHT showed the highest fatigue strength \u0000of 868 MPa due to high tensile strength, hardness and existing of high \u0000percentages of residual β phase in the microstructure. However, DSHT reported lower fatigue \u0000strength of 743 MPa due to increasing grain size of α phase. The fracture surface of fatigue samples showed cleavage ductile \u0000fracture mode for both heat treatment cycles.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133043777","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 : 2019-03-31DOI: 10.4236/OJMETAL.2019.91001
R. Elshaer, K. Ibrahim, A. Barakat, A. Farahat, R. Abbas
The α + β ↔ β phase transformation kinetics of TC21 Ti-alloy during continuous heating and cooling were studied using a dilatometric technique. Dilatometric heating curve exhibited that two characteristic reflection points can be observed with increasing the heating temperature. Ts referred to the initial transformation temperature of α + β → β and Tf referred to the final transformation temperature of α + β → β. Ts was reported at 720°C, whereas the corresponding Tf was obtained at 950°C. The initial and final transforming temperatures by the first derivative curve were reported at 730°C and 955°C, respectively, which are close to the values obtained in the dilatometric heating curve. Dilatometric cooling curve showed that the starting temperature of β → β + α phase transformation was 880°C; however, the corresponding finishing temperature was 670°C. The starting and finishing temperatures using the first derivative curve were obtained at 665°C and 885°C, respectively. The first derivative for the studied dilatometric heating and cooling curves showed that the starting and finishing temperatures of α + β ↔ β phase transformation were more accurate and objective. Results show the α + β → β transformation heating curve exhibits a typical S-shaped pattern.
{"title":"Determination of Phase Transformation for TC21 Ti-Alloy by Dilatometry Method","authors":"R. Elshaer, K. Ibrahim, A. Barakat, A. Farahat, R. Abbas","doi":"10.4236/OJMETAL.2019.91001","DOIUrl":"https://doi.org/10.4236/OJMETAL.2019.91001","url":null,"abstract":"The α + β ↔ β phase transformation kinetics of TC21 Ti-alloy during continuous heating and cooling were studied using a dilatometric technique. Dilatometric heating curve exhibited that two characteristic reflection points can be observed with increasing the heating temperature. Ts referred to the initial transformation temperature of α + β → β and Tf referred to the final transformation temperature of α + β → β. Ts was reported at 720°C, whereas the corresponding Tf was obtained at 950°C. The initial and final transforming temperatures by the first derivative curve were reported at 730°C and 955°C, respectively, which are close to the values obtained in the dilatometric heating curve. Dilatometric cooling curve showed that the starting temperature of β → β + α phase transformation was 880°C; however, the corresponding finishing temperature was 670°C. The starting and finishing temperatures using the first derivative curve were obtained at 665°C and 885°C, respectively. The first derivative for the studied dilatometric heating and cooling curves showed that the starting and finishing temperatures of α + β ↔ β phase transformation were more accurate and objective. Results show the α + β → β transformation heating curve exhibits a typical S-shaped pattern.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126339818","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 : 1900-01-01DOI: 10.4236/ojmetal.2023.131001
Ansah-Asiedu Junior, Mensah Fiifi Ebenezer, Vicku Charles, Samuel Nii Adamah Sampah, H. Barfi-Mensah, Anita Akwaa Toffah
{"title":"Design Intervention: An Artistic Strategy (A Strategy) to Minimize Text Fading and Metal Commemorative Plaque Theft in Ghana","authors":"Ansah-Asiedu Junior, Mensah Fiifi Ebenezer, Vicku Charles, Samuel Nii Adamah Sampah, H. Barfi-Mensah, Anita Akwaa Toffah","doi":"10.4236/ojmetal.2023.131001","DOIUrl":"https://doi.org/10.4236/ojmetal.2023.131001","url":null,"abstract":"","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115324294","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 : 1900-01-01DOI: 10.4236/ojmetal.2022.121001
R. Mejri, T. Aguili
In most studies of microstrip circuits, the majority of researchers assume that the microstrip structures studied have flat metallic conductors of finite widths but without thickness. But in reality these types of structures integrate metallic copper conductors of different thicknesses. If we neglect this thickness we introduce error in the electrical parameters of the microstrip structure, which affects the effective permittivity, the characteristic impedance, the adaptation of the circuit, the resonance frequency, etc. Given the importance of this parameter (thickness of the metal of micro rubon structures), rigorous electro-magnetic modeling of the thick micro rubon line based on the skin effect phenomenon (In fact at high frequency the skin effect phenomenon occurs and the current only flows on the periphery of the conductor) has been proposed to improve the studied electric model and ensure the increase in the precision of the analysis method used: Wave concept iterative process. The good agreement between the simulated and published data justifies the improvement of the model.
{"title":"Rigorous Electromagnetic Modeling of a Micro Strip Line Incorporating a Flat and Thick Metallic Conductor Based on the Skin Effect Phenomenon","authors":"R. Mejri, T. Aguili","doi":"10.4236/ojmetal.2022.121001","DOIUrl":"https://doi.org/10.4236/ojmetal.2022.121001","url":null,"abstract":"In most studies of microstrip circuits, the majority of researchers assume that the microstrip structures studied have flat metallic conductors of finite widths but without thickness. But in reality these types of structures integrate metallic copper conductors of different thicknesses. If we neglect this thickness we introduce error in the electrical parameters of the microstrip structure, which affects the effective permittivity, the characteristic impedance, the adaptation of the circuit, the resonance frequency, etc. Given the importance of this parameter (thickness of the metal of micro rubon structures), rigorous electro-magnetic modeling of the thick micro rubon line based on the skin effect phenomenon (In fact at high frequency the skin effect phenomenon occurs and the current only flows on the periphery of the conductor) has been proposed to improve the studied electric model and ensure the increase in the precision of the analysis method used: Wave concept iterative process. The good agreement between the simulated and published data justifies the improvement of the model.","PeriodicalId":146719,"journal":{"name":"Open Journal of Metal","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115386717","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 : 1900-01-01DOI: 10.4236/ojmetal.2021.113003
Ahmed Negm, S. Mohamed, M. Ibrahim, I. Moussa, K. Ibrahim
This investigation studies the impact strength, tensile strength, hardness, and wear behavior of thin wall austempered and intercritically austempered ductile iron samples with a chemical composition of 3.37% C, 2.7% Si, 0.30% Mn, 0.01% S, and 0.01% P. The austempered samples were austenitized at 900˚C for 1 h and rapidly quenched in a salt bath furnace at 375˚C for 1 h. The intercritically austempered samples were sub-austenitized at 810˚C for 1 h and rapidly quenched in a salt bath furnace at 375˚C for 1 h. The properties of the austempered and intercritically austempered thin wall plates of 5, 10, and 15 mm thickness were evaluated and compared to the as-cast samples. Austempering process affects greatly the tensile properties of all cast thicknesses where ultimate strength reached 1004 MPa for 5-mm thickness. Optimum impact toughness of 40 J was obtained for the austempered samples of 10-and 15-mm thicknesses. The intercritically austempered samples showed properties between the austempered and as-cast samples. Maximum wear resistance was also reported for the austempered samples due to containing retained austenite in the structure which in turn transformed into martensite that increases well the wear resistance. Maximum ultimate strength (1056)
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