Sintha Prima Widowati Gunawan, T. Matsui, T. Machimura
Despite available remote sensing data, technical challenges in developing countries have hindered local urban authorities from updating periodic land cover maps. Therefore, this study proposed a practical approach for regions with insufficient ground truth data. The study implemented a machine learning algorithm using single date medium spatial resolution data to build a classifier for separating Urban and Non-Urban zones. Then, the classifier was employed on multiple dates in 1999, 2005, and 2011 to corroborate its robustness. Results showed the stochastic gradient boosting (SGB) algorithm succeeded in building a robust classifier using the digital number value of LANDSAT-5TM 2005 with an overall accuracy of 0.76 and an area under curve receiver operator characteristic (AUC-ROC) value of 0.83. Moreover, the classifier predicted that urban areas in Yogyakarta, Indonesia, reached 24,099 (hectares) ha; 26,598 ha; and 22,650 ha in 1999, 2005, and 2011, respectively. The classifier's performance in predicting multiple datasets combined with histogram matching of medium spatial resolution data showed satisfactory results comparable to reference data from Statistics Indonesia, indicating sufficient accuracy for areal-integrated multi-temporal urbanization monitoring.
{"title":"Stochastic gradient boosting for urban change detection using multi-temporal LANDSAT-5TM in Yogyakarta, Indonesia","authors":"Sintha Prima Widowati Gunawan, T. Matsui, T. Machimura","doi":"10.29037/ajstd.961","DOIUrl":"https://doi.org/10.29037/ajstd.961","url":null,"abstract":"Despite available remote sensing data, technical challenges in developing countries have hindered local urban authorities from updating periodic land cover maps. Therefore, this study proposed a practical approach for regions with insufficient ground truth data. The study implemented a machine learning algorithm using single date medium spatial resolution data to build a classifier for separating Urban and Non-Urban zones. Then, the classifier was employed on multiple dates in 1999, 2005, and 2011 to corroborate its robustness. Results showed the stochastic gradient boosting (SGB) algorithm succeeded in building a robust classifier using the digital number value of LANDSAT-5TM 2005 with an overall accuracy of 0.76 and an area under curve receiver operator characteristic (AUC-ROC) value of 0.83. Moreover, the classifier predicted that urban areas in Yogyakarta, Indonesia, reached 24,099 (hectares) ha; 26,598 ha; and 22,650 ha in 1999, 2005, and 2011, respectively. The classifier's performance in predicting multiple datasets combined with histogram matching of medium spatial resolution data showed satisfactory results comparable to reference data from Statistics Indonesia, indicating sufficient accuracy for areal-integrated multi-temporal urbanization monitoring.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48798065","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}
A novel high gain miniaturized rectangular microstrip patch antenna is proposed with a high front-to-back ratio (FBR) using a modified feed line and two single-sided substrate layers to operate at 2.4 GHz frequency. The feed line is modified using a step impedance technique to achieve resonance at the operating frequency. The matched impedance of the feed line helps achieve enhanced bandwidth and antenna miniaturization. The substrate layers are introduced to achieve an enhanced gain and FBR of 6.329 dBi and 27.64 dB, respectively. The impedance bandwidths of 106.9 and 94.1 MHz are achieved for the two separate designs. These proposed designs have a total circuit area occupancy of 0.4 ?0 × 0.304 ?0. The antenna has been designed and fabricated using FR4 substrate material. The measured results are in good agreement with the simulated results.
{"title":"Design of High Gain and Improved Front-to-Back Ratio Multilayer Microstrip Patch Antenna using Modified Feed Line","authors":"Partha Kumar Deb, T. Moyra, B. Bhattacharyya","doi":"10.29037/ajstd.772","DOIUrl":"https://doi.org/10.29037/ajstd.772","url":null,"abstract":"A novel high gain miniaturized rectangular microstrip patch antenna is proposed with a high front-to-back ratio (FBR) using a modified feed line and two single-sided substrate layers to operate at 2.4 GHz frequency. The feed line is modified using a step impedance technique to achieve resonance at the operating frequency. The matched impedance of the feed line helps achieve enhanced bandwidth and antenna miniaturization. The substrate layers are introduced to achieve an enhanced gain and FBR of 6.329 dBi and 27.64 dB, respectively. The impedance bandwidths of 106.9 and 94.1 MHz are achieved for the two separate designs. These proposed designs have a total circuit area occupancy of 0.4 ?0 × 0.304 ?0. The antenna has been designed and fabricated using FR4 substrate material. The measured results are in good agreement with the simulated results.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48165473","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}
Prakoso Bhairawa Putera, S. Suryanto, S. Ningrum, I. Widianingsih, Y. Rianto
The application of mixed methods has been widely implemented in several studies, particularly in the field of public policy; however, the implementation of convergent parallel mixed methods has been limited. Thus, such methods are appropriate to reveal the science, technology, and innovation (STI) policy dynamics in Indonesia during the 1945–2020 period, as policy dynamics research attempts to reveal the evolution of the changes regarding the policy itself. The following five concepts are analyzed through convergent parallel mixed methods: 1) regime/government change, 2) institutional change/transformation, 3) change in policy issuance, direction, and content, 4) actor role and existence, and 5) policy object input and output. This article discusses the method details, from the paradigm, research dataset, and technique selection for collecting and analyzing research data to the research implementation.
{"title":"Using Convergent Parallel Mixed Methods and Datasets for Science, Technology, and Innovation Policy Dynamics Research in Indonesia","authors":"Prakoso Bhairawa Putera, S. Suryanto, S. Ningrum, I. Widianingsih, Y. Rianto","doi":"10.29037/ajstd.845","DOIUrl":"https://doi.org/10.29037/ajstd.845","url":null,"abstract":"The application of mixed methods has been widely implemented in several studies, particularly in the field of public policy; however, the implementation of convergent parallel mixed methods has been limited. Thus, such methods are appropriate to reveal the science, technology, and innovation (STI) policy dynamics in Indonesia during the 1945–2020 period, as policy dynamics research attempts to reveal the evolution of the changes regarding the policy itself. The following five concepts are analyzed through convergent parallel mixed methods: 1) regime/government change, 2) institutional change/transformation, 3) change in policy issuance, direction, and content, 4) actor role and existence, and 5) policy object input and output. This article discusses the method details, from the paradigm, research dataset, and technique selection for collecting and analyzing research data to the research implementation.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42545869","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}
Wisnu Arya Gemilang, Ulung Jantama Wisha, Mas Agus Mardyanto
The Pademawu coast has rapidly transformed into salt ponds, causing seawater intrusion and pollution. This study aims to examine the quality of groundwater in the surrounding settlement area of Pademawu and assess its eligibility for daily use. The psychochemical parameters of groundwater are measured in situ. Groundwater samples from several stations are analyzed in the laboratory and used to collect several chemical compounds, including Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, SO42-, Fe2+, Mn2+, F-, NO2-, NO3, and CaCO3. The detected concentrations are then used to calculate TH, sodium adsorption ratio (SAR), %Na, PI, KR, and MH. Hydrochemical calculation and interpretation are also performed. The groundwater characteristics are determined according to TDS, conductivity, and water quality index (WQI). Results showed that the groundwater facies are predominated by Ca-HCO3 (50%) in the northern and middle study areas and Na-Cl (37%) in the salt farming area. The groundwater is categorized as SAR (C2S1) in the north and SAR (C4S2) in the south. The primary groundwater consists of Na+ and Cl- (dominant cation and anion) originating from salt farming. The TDS in the salt farming area ranges from 1000 mg/L to 3000 mg/L (slightly saline). The WQI ranges from 39.0 to 735.4, which encompasses excellent water, good water, very poor water, and unsuitable for consumption. Salt farming infiltration toward unconfined aquifers is the primary factor causing groundwater pollution. Mitigation efforts to minimize scattered infiltration must be applied in the Pademawu Subdistrict by modifying the system between salt farming and settlement areas.
{"title":"Hydrogeochemical Analysis of Unconfined Groundwater in the Surrounding Salt Farming Areas of Pademawu, Madura, Indonesia","authors":"Wisnu Arya Gemilang, Ulung Jantama Wisha, Mas Agus Mardyanto","doi":"10.29037/ajstd.793","DOIUrl":"https://doi.org/10.29037/ajstd.793","url":null,"abstract":"The Pademawu coast has rapidly transformed into salt ponds, causing seawater intrusion and pollution. This study aims to examine the quality of groundwater in the surrounding settlement area of Pademawu and assess its eligibility for daily use. The psychochemical parameters of groundwater are measured in situ. Groundwater samples from several stations are analyzed in the laboratory and used to collect several chemical compounds, including Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, SO42-, Fe2+, Mn2+, F-, NO2-, NO3, and CaCO3. The detected concentrations are then used to calculate TH, sodium adsorption ratio (SAR), %Na, PI, KR, and MH. Hydrochemical calculation and interpretation are also performed. The groundwater characteristics are determined according to TDS, conductivity, and water quality index (WQI). Results showed that the groundwater facies are predominated by Ca-HCO3 (50%) in the northern and middle study areas and Na-Cl (37%) in the salt farming area. The groundwater is categorized as SAR (C2S1) in the north and SAR (C4S2) in the south. The primary groundwater consists of Na+ and Cl- (dominant cation and anion) originating from salt farming. The TDS in the salt farming area ranges from 1000 mg/L to 3000 mg/L (slightly saline). The WQI ranges from 39.0 to 735.4, which encompasses excellent water, good water, very poor water, and unsuitable for consumption. Salt farming infiltration toward unconfined aquifers is the primary factor causing groundwater pollution. Mitigation efforts to minimize scattered infiltration must be applied in the Pademawu Subdistrict by modifying the system between salt farming and settlement areas.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41658735","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}
One of the state-of-the-art technologies for metal fabrication is laser powder bed fusion, which includes the following printing techniques: selective laser melting, selective laser sintering, direct metal laser sintering, and electron beam melting. This work examines defect formation in laser powder bed fusion, predominately focusing on selective laser melting. It also explores recent research findings on defect formation and classification and analyzes various internal defects, such as porosity, lack of fusion, balling, and solidification cracking. The influence of process parameters on defect formation and the effect of defects on mechanical properties are analyzed. This review also discusses defect inspection technologies (melt pool, scan path, and slice monitoring), defect mitigation strategies (online detection, process parameters, and numerical simulation), and their applications in additive manufacturing, such as laser powder bed fusion. This review would aid manufacturers in determining the root cause of defect formation and developing inspection technologies and mitigation strategies.
{"title":"Defect and Distortion in Powder Bed Fusion of Metal Additive Manufacturing Parts","authors":"A. Maurya, Amit Kumar","doi":"10.29037/ajstd.852","DOIUrl":"https://doi.org/10.29037/ajstd.852","url":null,"abstract":"One of the state-of-the-art technologies for metal fabrication is laser powder bed fusion, which includes the following printing techniques: selective laser melting, selective laser sintering, direct metal laser sintering, and electron beam melting. This work examines defect formation in laser powder bed fusion, predominately focusing on selective laser melting. It also explores recent research findings on defect formation and classification and analyzes various internal defects, such as porosity, lack of fusion, balling, and solidification cracking. The influence of process parameters on defect formation and the effect of defects on mechanical properties are analyzed. This review also discusses defect inspection technologies (melt pool, scan path, and slice monitoring), defect mitigation strategies (online detection, process parameters, and numerical simulation), and their applications in additive manufacturing, such as laser powder bed fusion. This review would aid manufacturers in determining the root cause of defect formation and developing inspection technologies and mitigation strategies.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46973910","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}
The use of black soldier fly (BSF) as a bioconversion agent has become an emerging breakthrough in waste processing. Organic wastes, such as household waste and livestock manure, can be used as a growth medium for BSF larvae and converted into favorable products. The average composting time of BSF larvae is around 12– 15 days, which is faster than that of microbes or earthworms (4–5 weeks). BSF shows potential as a feed and food ingredient because it has a high nutritional content, such as enzyme, chitin, medium-chain fatty acid, and antimicrobial peptides, and can be used as a functional food ingredient. From an economical perspective, the short composting period and the role of BSF as a feed and food alternatives can benefit producers and consumers. The safety aspects of BSF utilization, including microbial safety, chemical safety, and environmental safety, warrant clarification to ensure BSF safety. However, some challenges arise regarding the use of BSF larvae (BSFL) as a bioconversion agent, such as for heavy metal residues, pesticide residues, pathogens, and antimicrobial gene transmission and residues that require the best composting strategy for mitigation. The environmental safety of organic waste treated with BSFL has a good impact; therefore, this strategy can be used to reduce global warming. Research must focus on effectively and safely enhancing the cultivation and processing of BSF and its applications as a functional food. In conclusion, BSF is a profitable alternative for organic waste bioconversion in developed and developing countries.
{"title":"Black Soldier Fly (Hermetia illucens) as a Potential Agent of Organic Waste Bioconversion","authors":"L. Purnamasari, H. Khasanah","doi":"10.29037/ajstd.780","DOIUrl":"https://doi.org/10.29037/ajstd.780","url":null,"abstract":"The use of black soldier fly (BSF) as a bioconversion agent has become an emerging breakthrough in waste processing. Organic wastes, such as household waste and livestock manure, can be used as a growth medium for BSF larvae and converted into favorable products. The average composting time of BSF larvae is around 12– 15 days, which is faster than that of microbes or earthworms (4–5 weeks). BSF shows potential as a feed and food ingredient because it has a high nutritional content, such as enzyme, chitin, medium-chain fatty acid, and antimicrobial peptides, and can be used as a functional food ingredient. From an economical perspective, the short composting period and the role of BSF as a feed and food alternatives can benefit producers and consumers. The safety aspects of BSF utilization, including microbial safety, chemical safety, and environmental safety, warrant clarification to ensure BSF safety. However, some challenges arise regarding the use of BSF larvae (BSFL) as a bioconversion agent, such as for heavy metal residues, pesticide residues, pathogens, and antimicrobial gene transmission and residues that require the best composting strategy for mitigation. The environmental safety of organic waste treated with BSFL has a good impact; therefore, this strategy can be used to reduce global warming. Research must focus on effectively and safely enhancing the cultivation and processing of BSF and its applications as a functional food. In conclusion, BSF is a profitable alternative for organic waste bioconversion in developed and developing countries.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44899873","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}
At 308 K, using a 9.37 GHz dielectric relaxation setup, dielectric studies of hydrogen bonded complexes of benzamide and acetamide with 4-fluorophenol, 4-bromophenol, 4-chlorophenol, and 4-iodophenol in benzene were performed. Various dielectric parameters (such as ??, ??, ?0, and ??) were tested. The steric interactions of the proton donor determined the group rotation relaxation time t(2), whereas the significance of Higasi’s single frequency method for multiple relaxation time t(1) was determined by the hydrogen bonding power of the phenolic hydrogen. The presence of a 1:1 complex system between the prepared samples, as well as a charge transfer between the free hydroxyl group of phenols and the carbonyl group of amides was confirmed by the fact that the relaxation time and molar free energy activation of the 1:1 molar ratio were greater than some other higher molar ratios (i.e. 3:1, 2:1, 1:2, 1:3).
{"title":"Dielectric Relaxation Studies of Hydrogen Bonded Complexes of Benzamide and Acetamide with 4-substituted Phenols Using X-band Microwave Frequency","authors":"A. Basha, F. Khan","doi":"10.29037/ajstd.711","DOIUrl":"https://doi.org/10.29037/ajstd.711","url":null,"abstract":"At 308 K, using a 9.37 GHz dielectric relaxation setup, dielectric studies of hydrogen bonded complexes of benzamide and acetamide with 4-fluorophenol, 4-bromophenol, 4-chlorophenol, and 4-iodophenol in benzene were performed. Various dielectric parameters (such as ??, ??, ?0, and ??) were tested. The steric interactions of the proton donor determined the group rotation relaxation time t(2), whereas the significance of Higasi’s single frequency method for multiple relaxation time t(1) was determined by the hydrogen bonding power of the phenolic hydrogen. The presence of a 1:1 complex system between the prepared samples, as well as a charge transfer between the free hydroxyl group of phenols and the carbonyl group of amides was confirmed by the fact that the relaxation time and molar free energy activation of the 1:1 molar ratio were greater than some other higher molar ratios (i.e. 3:1, 2:1, 1:2, 1:3).","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44973702","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}
M. N. Malawani, M. Marfai, A. G. H. Yoga, T. Handayani, A. Cahyadi, Muhammad Isnaini Sadali, Mohamad Zaki Mahasin, Hendratmoro, Suadi, Maryadi Budi Wiyono
The government of Indonesia has faced several challenges to its goal of achieving salt self-sufficiency, necessitating the formulation and implementation of strategic steps to increase salt production. Among its islands, Java has a great deal of potential for salt production, as does the Special Region of Yogyakarta, where the government has initiated salt farming development as part of its coastal community empowerment program. This study aimed to (1) evaluate the land suitability of existing salt farms and (2) identify potential sites and make a productivity estimation of salt farms in the Special Region of Yogyakarta, with the broad objective of demonstrating a rapid land assessment for salt farming development using the combination GIS and field survey. The approach was carried out in three phases; i.e., the analyses of land availability, land characteristics, and land recommendations. On-screen digitizing using GIS was applied to identify land availability through several data sources (satellite imagery and a land-use map from the Indonesian topographic map). This process led to the discovery of 19 sites. Land characteristics and land recommendations analysis were carried out in those sites, resulting in multiple land suitability classes, mostly in the S2 class (moderately suitable). Several impediment factors, such as wind, material texture, and temperature, were also identified, along with other obstacles including high tide and tsunami exposure. In terms of supporting the Indonesian salt self-sufficiency program, these results are significant, with salt productivity estimations of the potential sites meeting the target set by the Ministry of Marine Affairs and Fisheries of Indonesia.
{"title":"Rapid Land Assessment for Salt Farming Development in the Coastal Area of the Special Region of Yogyakarta, Indonesia","authors":"M. N. Malawani, M. Marfai, A. G. H. Yoga, T. Handayani, A. Cahyadi, Muhammad Isnaini Sadali, Mohamad Zaki Mahasin, Hendratmoro, Suadi, Maryadi Budi Wiyono","doi":"10.29037/ajstd.694","DOIUrl":"https://doi.org/10.29037/ajstd.694","url":null,"abstract":"The government of Indonesia has faced several challenges to its goal of achieving salt self-sufficiency, necessitating the formulation and implementation of strategic steps to increase salt production. Among its islands, Java has a great deal of potential for salt production, as does the Special Region of Yogyakarta, where the government has initiated salt farming development as part of its coastal community empowerment program. This study aimed to (1) evaluate the land suitability of existing salt farms and (2) identify potential sites and make a productivity estimation of salt farms in the Special Region of Yogyakarta, with the broad objective of demonstrating a rapid land assessment for salt farming development using the combination GIS and field survey. The approach was carried out in three phases; i.e., the analyses of land availability, land characteristics, and land recommendations. On-screen digitizing using GIS was applied to identify land availability through several data sources (satellite imagery and a land-use map from the Indonesian topographic map). This process led to the discovery of 19 sites. Land characteristics and land recommendations analysis were carried out in those sites, resulting in multiple land suitability classes, mostly in the S2 class (moderately suitable). Several impediment factors, such as wind, material texture, and temperature, were also identified, along with other obstacles including high tide and tsunami exposure. In terms of supporting the Indonesian salt self-sufficiency program, these results are significant, with salt productivity estimations of the potential sites meeting the target set by the Ministry of Marine Affairs and Fisheries of Indonesia.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42054718","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}
Suresh Palla, Suresh Vanguri, S. Ramakrishna, S. Chaturvedi, B. Mohapatra
The cement industry has been identified as one of the main contributors to climate change due to greenhouse gas emissions, mainly CO2. Therefore, to meet CO2 reduction targets, cement producers are working on different methods of minimizing its emission, one of which is alternative clinkers. This study assessed the impact of variations of the raw mix design, concerning the type and proportions of materials, on the formation of calcium sulphoaluminate belite-type clinkers. Various materials were used to produce raw mixes for different percentages of belite, yeeliminite, and other minerals in resultant clinkers. Computer-based theoretical mix designs were designed with different percentages of SiO2, CaO, Al2O3, Fe2O3, and SO3 and then the designed mixes were fired in a laboratory furnace at 1250oC with 20 min retention time. The resultant clinker samples were characterized with X-ray diffraction for product minerals. The quantification of minerals in every sample was carried out with Rietveld refinement. The obtained results confirmed the correlation between the mineralogy and chemical constituents in the raw mix. The C4AF percentage of the resultant clinker samples increased with an increase in Fe2O3 percentage. C4A3$ content varied with the amounts of Al2O3, SO3, and CaO. The mineral percentage of C2S in the designed mixes had a clear correlation with the constituents of SiO2 and CaO. Anhydrite percentage in the resultant minerals changed with the SO3 content in the raw mix. These results should aid in the determination of the optimum amount of chemical constituents and minerals required for the development of calcium sulphoaluminate clinker.
{"title":"BCSA Rawmix Design: Correlation between Chemical Constituents and Mineralogy","authors":"Suresh Palla, Suresh Vanguri, S. Ramakrishna, S. Chaturvedi, B. Mohapatra","doi":"10.29037/ajstd.705","DOIUrl":"https://doi.org/10.29037/ajstd.705","url":null,"abstract":"The cement industry has been identified as one of the main contributors to climate change due to greenhouse gas emissions, mainly CO2. Therefore, to meet CO2 reduction targets, cement producers are working on different methods of minimizing its emission, one of which is alternative clinkers. This study assessed the impact of variations of the raw mix design, concerning the type and proportions of materials, on the formation of calcium sulphoaluminate belite-type clinkers. Various materials were used to produce raw mixes for different percentages of belite, yeeliminite, and other minerals in resultant clinkers. Computer-based theoretical mix designs were designed with different percentages of SiO2, CaO, Al2O3, Fe2O3, and SO3 and then the designed mixes were fired in a laboratory furnace at 1250oC with 20 min retention time. The resultant clinker samples were characterized with X-ray diffraction for product minerals. The quantification of minerals in every sample was carried out with Rietveld refinement. The obtained results confirmed the correlation between the mineralogy and chemical constituents in the raw mix. The C4AF percentage of the resultant clinker samples increased with an increase in Fe2O3 percentage. C4A3$ content varied with the amounts of Al2O3, SO3, and CaO. The mineral percentage of C2S in the designed mixes had a clear correlation with the constituents of SiO2 and CaO. Anhydrite percentage in the resultant minerals changed with the SO3 content in the raw mix. These results should aid in the determination of the optimum amount of chemical constituents and minerals required for the development of calcium sulphoaluminate clinker.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43315907","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}
Additive manufacturing technology is becoming popular in the industry because it allows the manufacturer to fabricate cost-effective, strong, lightweight, and complex-shaped parts directly from 3D design data as compared with the conventional manufacturing method. Inconel 718 alloy is the most demanding material in aviation as well as in the automobile industry, in terms of manufacturing high-performance parts. In this study, Inconel 718 samples were built using the direct metal laser sintering process, and standard heat treatment was performed on the samples to improve their microstructure and mechanical properties. The as-built samples exhibited good grain structure with fine laves phases, but the matrix was free from ?' and ?" phases. During the heat treatment, the strengthening phases ?' and ?" precipitated. The mechanical properties of as-built and heat-treated samples were analysed and compared. Tensile tests revealed that the direct-aged sample had the higher tensile strength compared with the other conditions, whereas the as-built samples had higher ductility. Finally, fractography and microstructure analysis were performed to measure the failure modes of tensile specimens.
{"title":"Study of Microstructure and Mechanical Properties of As-built and Heat-treated Additive Manufactured Inconel 718 Alloy","authors":"A. Maurya, Ajay Kumar","doi":"10.29037/ajstd.724","DOIUrl":"https://doi.org/10.29037/ajstd.724","url":null,"abstract":"Additive manufacturing technology is becoming popular in the industry because it allows the manufacturer to fabricate cost-effective, strong, lightweight, and complex-shaped parts directly from 3D design data as compared with the conventional manufacturing method. Inconel 718 alloy is the most demanding material in aviation as well as in the automobile industry, in terms of manufacturing high-performance parts. In this study, Inconel 718 samples were built using the direct metal laser sintering process, and standard heat treatment was performed on the samples to improve their microstructure and mechanical properties. The as-built samples exhibited good grain structure with fine laves phases, but the matrix was free from ?' and ?\" phases. During the heat treatment, the strengthening phases ?' and ?\" precipitated. The mechanical properties of as-built and heat-treated samples were analysed and compared. Tensile tests revealed that the direct-aged sample had the higher tensile strength compared with the other conditions, whereas the as-built samples had higher ductility. Finally, fractography and microstructure analysis were performed to measure the failure modes of tensile specimens.","PeriodicalId":8479,"journal":{"name":"Asean Journal on Science and Technology for Development","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47582103","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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