Hardianto Wibowo, Wildan Suharso, Yufis Azhar, G. Wicaksono, A. E. Minarno, D. Harmanto
Music is the art of combining frequencies. A balance of frequencies gives rise to a harmonious tone. Several features of music can be analyzed, and they include sociocultural background, lyrics, mood, tempo, rhythm, harmony, melody, timbre, and instrumentation. In this study, we use the frequency of instrumentation as a feature for classification because each instrument has a frequency range. To test this frequency range, we use five music genres and one music playing skill. The five genres are dangdut, electronic dance music (EDM), metal, pop/rock, and reggae. The music playing skill is acoustic. Active frequencies are tested using the k-nearest neighbor method, and the results serve as basis of the accuracy of music classification. The classification accuracy for EDM, metal, and acoustic is over 70%, whereas that for dangdut, pop/rock, and reggae is less than 60%. In sum, the accuracy of music classification is influenced by the similarities in the music instruments used and the tempo.
{"title":"Music Information Retrieval Based on Active Frequency","authors":"Hardianto Wibowo, Wildan Suharso, Yufis Azhar, G. Wicaksono, A. E. Minarno, D. Harmanto","doi":"10.7454/mst.v25i2.3977","DOIUrl":"https://doi.org/10.7454/mst.v25i2.3977","url":null,"abstract":"Music is the art of combining frequencies. A balance of frequencies gives rise to a harmonious tone. Several features of music can be analyzed, and they include sociocultural background, lyrics, mood, tempo, rhythm, harmony, melody, timbre, and instrumentation. In this study, we use the frequency of instrumentation as a feature for classification because each instrument has a frequency range. To test this frequency range, we use five music genres and one music playing skill. The five genres are dangdut, electronic dance music (EDM), metal, pop/rock, and reggae. The music playing skill is acoustic. Active frequencies are tested using the k-nearest neighbor method, and the results serve as basis of the accuracy of music classification. The classification accuracy for EDM, metal, and acoustic is over 70%, whereas that for dangdut, pop/rock, and reggae is less than 60%. In sum, the accuracy of music classification is influenced by the similarities in the music instruments used and the tempo.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49493185","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 present work was carried out with the development of hybrid polymer electrolytes (HPEs) by using carboxymethyl cellulose (CMC)–polyvinyl alcohol (PVA) doped with different contents of lithium nitrate (LiNO3) for the determination of their structural and conduction properties. The structural analysis was conducted by using Fourier transform infra-red spectroscopy and showed the interaction between the blend host polymer and ionic dopant, which formed via the coordinating site of CMC-PVA and Li + -NO3 − . The complexes of CMC-PVA doped LiNO3 led to an increment in ionic conductivity, as observed by electrical impedance spectroscopy, and the sample containing 20 wt% LiNO3 obtained the highest ionic conductivity of 3.54 × 10 −3 S cm −1 at room temperature. The ionic conductivity at different temperatures (from 303 K to 343 K) was measured and found to obey the Arrhenius rule. The activation energies of the HPEs were computed based on the Arrhenius equation and were inversely proportional to the ionic conductivity. The highest ionic conducting sample was fabricated into an electrical double layer capacitor (EDLC). Cyclic voltammetry (CV) was used to study the electrochemical performance of the EDLC. A high value of Cs was obtained at 2 mVs −1 due to the utilization of ions in the vacant sites of the electrode material.
{"title":"Improvement of Electrical Properties of CMC-PVA Doped with Various Contents of LiNO3 as an Application for Hybrid Polymer Electrolytes","authors":"A. Zulkifli, Norfatihah Mazuki, A. S. Samsudin","doi":"10.7454/mst.v25i2.3839","DOIUrl":"https://doi.org/10.7454/mst.v25i2.3839","url":null,"abstract":"The present work was carried out with the development of hybrid polymer electrolytes (HPEs) by using carboxymethyl cellulose (CMC)–polyvinyl alcohol (PVA) doped with different contents of lithium nitrate (LiNO3) for the determination of their structural and conduction properties. The structural analysis was conducted by using Fourier transform infra-red spectroscopy and showed the interaction between the blend host polymer and ionic dopant, which formed via the coordinating site of CMC-PVA and Li + -NO3 − . The complexes of CMC-PVA doped LiNO3 led to an increment in ionic conductivity, as observed by electrical impedance spectroscopy, and the sample containing 20 wt% LiNO3 obtained the highest ionic conductivity of 3.54 × 10 −3 S cm −1 at room temperature. The ionic conductivity at different temperatures (from 303 K to 343 K) was measured and found to obey the Arrhenius rule. The activation energies of the HPEs were computed based on the Arrhenius equation and were inversely proportional to the ionic conductivity. The highest ionic conducting sample was fabricated into an electrical double layer capacitor (EDLC). Cyclic voltammetry (CV) was used to study the electrochemical performance of the EDLC. A high value of Cs was obtained at 2 mVs −1 due to the utilization of ions in the vacant sites of the electrode material.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47057443","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}
P. Parikin, M. Dani, A. Dimyati, N. D. Purnamasari, B. Sugeng, M. Panitra, A. Insani, T. Priyanto, S. Mustofa, S. Syahbuddin, C. A. Huang
X-ray diffraction techniques were performed to determine the actual crystal structure of A2 austenitic stainless steel (ASS) as-cast and A2 ASS after arc plasma sintering (APS) for 2 s. Computations were conducted on the basis of the Bragg arithmetic formula by comparing the S 2 arithmetic with the interplanar spacing. The Bragg arithmetic formula is a simple series for the determination of the crystalline phase of materials based on the Miller indices of cubic shapes or other shapes. A2 ASS as-cast was identified to have a crystal structure of face-centered cubic with lattice parameter a = 3.58 Å. A similar crystal structure can still be detected in A2 ASS after APS for 2 s with lattice parameter a = 3.60 Å. This finding was confirmed by neutron diffraction measurements and optical–electron microscopy observations. Under the same conditions, both A2 ASS as-cast and A2 ASS after APS for 2 s have similar cast structures. The grain boundary formed in A2 ASS as-cast is thinner than that in A2 ASS after APS for 2 s, which is visible in its boundaries. Moreover, the grain structure of A2 ASS after APS for 2 s, which was originally elongated particles, became globular particles. Similarly, granular precipitates became concentrated and encompassed the steel matrix along the grain boundaries. Furthermore, scanning electron microscopy with energy-dispersive X-ray analysis showed that particles and islands in steel are distributed in the grains and at the grain boundaries, respectively. Precipitates are composed of C, Cr, Fe, and Ni. The elemental contents of Cr and C are dominant; thus, Cr23C6 precipitate is formed at the grain boundaries.
{"title":"Effect of Arc Plasma Sintering on the Structural and Microstructural Properties of Fe-Cr-Ni Austenitic Stainless Steels","authors":"P. Parikin, M. Dani, A. Dimyati, N. D. Purnamasari, B. Sugeng, M. Panitra, A. Insani, T. Priyanto, S. Mustofa, S. Syahbuddin, C. A. Huang","doi":"10.7454/mst.v25i2.3922","DOIUrl":"https://doi.org/10.7454/mst.v25i2.3922","url":null,"abstract":"X-ray diffraction techniques were performed to determine the actual crystal structure of A2 austenitic stainless steel (ASS) as-cast and A2 ASS after arc plasma sintering (APS) for 2 s. Computations were conducted on the basis of the Bragg arithmetic formula by comparing the S 2 arithmetic with the interplanar spacing. The Bragg arithmetic formula is a simple series for the determination of the crystalline phase of materials based on the Miller indices of cubic shapes or other shapes. A2 ASS as-cast was identified to have a crystal structure of face-centered cubic with lattice parameter a = 3.58 Å. A similar crystal structure can still be detected in A2 ASS after APS for 2 s with lattice parameter a = 3.60 Å. This finding was confirmed by neutron diffraction measurements and optical–electron microscopy observations. Under the same conditions, both A2 ASS as-cast and A2 ASS after APS for 2 s have similar cast structures. The grain boundary formed in A2 ASS as-cast is thinner than that in A2 ASS after APS for 2 s, which is visible in its boundaries. Moreover, the grain structure of A2 ASS after APS for 2 s, which was originally elongated particles, became globular particles. Similarly, granular precipitates became concentrated and encompassed the steel matrix along the grain boundaries. Furthermore, scanning electron microscopy with energy-dispersive X-ray analysis showed that particles and islands in steel are distributed in the grains and at the grain boundaries, respectively. Precipitates are composed of C, Cr, Fe, and Ni. The elemental contents of Cr and C are dominant; thus, Cr23C6 precipitate is formed at the grain boundaries.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41782241","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}
Dispatching is a critical part in current online shopping. It relates to how the delivery man assignment should minimize cost along with the service from a source to an end customer with an appropriate scheduled time. The problem arises as neither enough products to deliver nor delivery men are available for dispatch, resulting in suboptimal service and a waste of money. The study aimed to formulate the cost of restaurant dispatching for inducing a deep learning-based solution with the gated recurrent unit recurrent neural network to receive hourly order data and to engage the result for near feature delivery man schedule with minimum cost. The result showed that cost formulation minimized the number of delivery men times the wage per hour with the constraints of each delivery man carrying a maximum of five orders in one way and 11 work hours/day. The deep learning input model used 1078 historical data which were filtered using the Savitzky-Golay method. The root mean square errors of training and testing were 2.35 and 2.41, respectively. Moreover, the number of delivery men every hour was found in a range from one to four people. Furthermore, the deep learning approach saved costs of up to 43.8%.
{"title":"Predictive Delivery Man Assignment Problem using Deep Learning","authors":"R. P. Juarsa, Taufik Djatna","doi":"10.7454/mst.v25i2.3700","DOIUrl":"https://doi.org/10.7454/mst.v25i2.3700","url":null,"abstract":"Dispatching is a critical part in current online shopping. It relates to how the delivery man assignment should minimize cost along with the service from a source to an end customer with an appropriate scheduled time. The problem arises as neither enough products to deliver nor delivery men are available for dispatch, resulting in suboptimal service and a waste of money. The study aimed to formulate the cost of restaurant dispatching for inducing a deep learning-based solution with the gated recurrent unit recurrent neural network to receive hourly order data and to engage the result for near feature delivery man schedule with minimum cost. The result showed that cost formulation minimized the number of delivery men times the wage per hour with the constraints of each delivery man carrying a maximum of five orders in one way and 11 work hours/day. The deep learning input model used 1078 historical data which were filtered using the Savitzky-Golay method. The root mean square errors of training and testing were 2.35 and 2.41, respectively. Moreover, the number of delivery men every hour was found in a range from one to four people. Furthermore, the deep learning approach saved costs of up to 43.8%.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"1 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71343176","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}
h.faghihmaleki@gmail.com Abstract Various rehabilitation and strengthening procedures have been developed in recent decades. A study to determine which methods can be implemented to increase the useful life of the bridge before strengthening must be performed. In this study, the seismic behavior of a reinforced concrete bridge pier with dimension 3.5 × 3.5 m, which was reinforced by two steel and a concrete jacket, was investigated. Nonlinear geometric models and materials were analyzed to estimate the seismic parameters of the pier. Results show an increase in energy absorption, ultimate strength, and ductility for the steel jacket, as well as a greater increase in the concrete jacket. Using a box concrete jacket with a dimension of 3.5 × 3.5 m, the increase in percentages of energy absorption, ultimate strength, and ductility were 38, 14, and 13, respectively. Therefore, the concrete jacket enhances the mentioned
{"title":"Comparison of Concrete and Steel Jacket Methods for Reinforcing A Concrete Bridge Pier by Numerical and Experimental Studies","authors":"Hadi Faghihmaleki","doi":"10.7454/mst.v25i2.3909","DOIUrl":"https://doi.org/10.7454/mst.v25i2.3909","url":null,"abstract":"h.faghihmaleki@gmail.com Abstract Various rehabilitation and strengthening procedures have been developed in recent decades. A study to determine which methods can be implemented to increase the useful life of the bridge before strengthening must be performed. In this study, the seismic behavior of a reinforced concrete bridge pier with dimension 3.5 × 3.5 m, which was reinforced by two steel and a concrete jacket, was investigated. Nonlinear geometric models and materials were analyzed to estimate the seismic parameters of the pier. Results show an increase in energy absorption, ultimate strength, and ductility for the steel jacket, as well as a greater increase in the concrete jacket. Using a box concrete jacket with a dimension of 3.5 × 3.5 m, the increase in percentages of energy absorption, ultimate strength, and ductility were 38, 14, and 13, respectively. Therefore, the concrete jacket enhances the mentioned","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43860952","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. S. Auzani, C. Wibowo, R. Anggarani, Y. Nugroho, B. Sugiarto
Gasoline–ethanol–methanol (GEM) blends have been considered to replace pure gasoline as spark ignition engine fuel. Their physical and chemical properties and performance and emission measurements from real engines have been reported previously. However, a fundamental study that can explain the unique results of GEM compared with those of pure gasoline is lacking. This study aims to compare the laminar burning velocity of GEM blends at different mixtures, equivalence ratios, temperatures, and pressures with that of pure gasoline. A laminar flame propagation model and reaction mechanisms from the literature were were for a numerical simulation. In this study, the chemical components of real gasoline are simplified using a binary surrogate mixture. Results show that the laminar burning velocity of the GEM increased with the increase in temperature, ethanol, and methanol concentration, and it decreased with the increase in pressure. Sensitive reactions to laminar burning velocity are presented through a sensitivity analysis.
{"title":"Kinetic Modeling Study of Laminar Burning Velocity of Gasoline–Ethanol–Methanol Blends at Elevated Temperature and Pressure","authors":"A. S. Auzani, C. Wibowo, R. Anggarani, Y. Nugroho, B. Sugiarto","doi":"10.7454/mst.v25i2.4070","DOIUrl":"https://doi.org/10.7454/mst.v25i2.4070","url":null,"abstract":"Gasoline–ethanol–methanol (GEM) blends have been considered to replace pure gasoline as spark ignition engine fuel. Their physical and chemical properties and performance and emission measurements from real engines have been reported previously. However, a fundamental study that can explain the unique results of GEM compared with those of pure gasoline is lacking. This study aims to compare the laminar burning velocity of GEM blends at different mixtures, equivalence ratios, temperatures, and pressures with that of pure gasoline. A laminar flame propagation model and reaction mechanisms from the literature were were for a numerical simulation. In this study, the chemical components of real gasoline are simplified using a binary surrogate mixture. Results show that the laminar burning velocity of the GEM increased with the increase in temperature, ethanol, and methanol concentration, and it decreased with the increase in pressure. Sensitive reactions to laminar burning velocity are presented through a sensitivity analysis.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46540079","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}
Energy needs are increasing day by day, especially for developing countries, due to population growth and changing lifestyles. A suitable microgrid topology with renewable energy integration is considered to fulfill the people and society’s needs. This paper focuses on the design of AC microgrid topology for a nonelectrified village with the integration of PV uncertainties in both sitting and sizing. The development of an optimal algorithm based on the conductor use minimization and unbalanced load improvement is proposed. The shortest path is proposed to search for the minimum conductor use. Then, the algorithm for improving the unbalanced load with two different algorithms–phase sequence and first-fit bin packing with phase swapping–is compared based on the energy use indicator. Once the optimal AC microgrid topology is defined, the impact of the integration of PV uncertainties into the system is studied. Simulation results prove the effectiveness of the proposed method.
{"title":"Design of AC Microgrid Topology with Photovoltaic Uncertainties in a Rural Village","authors":"V. Vai","doi":"10.7454/MST.V25I1.3759","DOIUrl":"https://doi.org/10.7454/MST.V25I1.3759","url":null,"abstract":"Energy needs are increasing day by day, especially for developing countries, due to population growth and changing lifestyles. A suitable microgrid topology with renewable energy integration is considered to fulfill the people and society’s needs. This paper focuses on the design of AC microgrid topology for a nonelectrified village with the integration of PV uncertainties in both sitting and sizing. The development of an optimal algorithm based on the conductor use minimization and unbalanced load improvement is proposed. The shortest path is proposed to search for the minimum conductor use. Then, the algorithm for improving the unbalanced load with two different algorithms–phase sequence and first-fit bin packing with phase swapping–is compared based on the energy use indicator. Once the optimal AC microgrid topology is defined, the impact of the integration of PV uncertainties into the system is studied. Simulation results prove the effectiveness of the proposed method.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47523233","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. Orientilize, J. I. Rastandi, P. MarshaNiken, Krisna Adi S.S, Abimantrana Abimantrana
This study investigated the utilization of plastic-waste concrete as an effort to reduce urban waste problems. The waste plastic bottles were utilized to form the hollows of the hollow-core slabs (HCSs). The bottles were made of polyethylene terephthalate (PET). As a part of green research to reuse waste material, shredded PET was also added to the concrete mixture to improve the HCS strength. The cast-in-site HCS could be constructed without any difficulties. Three parameters were investigated: the effects of void content, shredded PET content, and steel-fiber (SF) content on the HCS ultimate bending capacity (Mu). Fifteen specimens were tested under static loads until failure, and the results were compared with those of the solid slab. Two different void contents 19% and 24% were studied. The other parameters were the shredded PET content (0.5% and 0.7%) and the SF content (0.19% and 0.32%). The Mu values of the HCS specimens were 12% to 16% less than that of the solid slab. However, the strengths were still within the theoretical capacity of the slab. The addition of the shredded PET could improve the HCS bending capacity by 18% to 38% compared with that of the solid slab. Similar results were also found for the specimens with SFs, whose Mu values were 11% to 46% greater than that of the solid slab.
{"title":"Experimental Study of Hollow-core Slab Containing Waste PET Bottles","authors":"M. Orientilize, J. I. Rastandi, P. MarshaNiken, Krisna Adi S.S, Abimantrana Abimantrana","doi":"10.7454/MST.V25I1.3677","DOIUrl":"https://doi.org/10.7454/MST.V25I1.3677","url":null,"abstract":"This study investigated the utilization of plastic-waste concrete as an effort to reduce urban waste problems. The waste plastic bottles were utilized to form the hollows of the hollow-core slabs (HCSs). The bottles were made of polyethylene terephthalate (PET). As a part of green research to reuse waste material, shredded PET was also added to the concrete mixture to improve the HCS strength. The cast-in-site HCS could be constructed without any difficulties. Three parameters were investigated: the effects of void content, shredded PET content, and steel-fiber (SF) content on the HCS ultimate bending capacity (Mu). Fifteen specimens were tested under static loads until failure, and the results were compared with those of the solid slab. Two different void contents 19% and 24% were studied. The other parameters were the shredded PET content (0.5% and 0.7%) and the SF content (0.19% and 0.32%). The Mu values of the HCS specimens were 12% to 16% less than that of the solid slab. However, the strengths were still within the theoretical capacity of the slab. The addition of the shredded PET could improve the HCS bending capacity by 18% to 38% compared with that of the solid slab. Similar results were also found for the specimens with SFs, whose Mu values were 11% to 46% greater than that of the solid slab.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41957041","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. Laksono, Y. Yen, R. A. Tanjung, T. A. Amatosa, R. Harwahyu
Bulk metallic glass (BMG) has good mechanical strength, high hardness, wear resistance, and corrosion resistance with promising application in various industries. However, for the industrial production of BMG, the main issue is how to overcome limitations of joining with other materials. The present study focuses on solder processing at low operating temperature to avoid exceeding the recrystallization temperature. A feasible joining process for BMG was developed using lead-free solders. The BMG surface is pre-plated with copper, nickel, or titanium as a wetting layer. The reaction temperature is set between the glass transition temperature of BMG and the melting point of the solder. After a reflowing and aging process, the joint sample was examined using SEM, EDS, EPMA, and XRD. The Cu–Zr based BMG can be successfully joined with Sn-58Bi solder after plating Cu on the BMG surface. A diffusion layer was observed and the thickness increased with longer aging time. The main components of the diffusion layer are ZrO2 and Cu10Zr7.
{"title":"Analysis of the Interfacial Reaction between Bulk Metallic Glass Coated Copper, Nickel, and Titanium with Lead-Free Solders","authors":"A. Laksono, Y. Yen, R. A. Tanjung, T. A. Amatosa, R. Harwahyu","doi":"10.7454/MST.V25I1.3860","DOIUrl":"https://doi.org/10.7454/MST.V25I1.3860","url":null,"abstract":"Bulk metallic glass (BMG) has good mechanical strength, high hardness, wear resistance, and corrosion resistance with promising application in various industries. However, for the industrial production of BMG, the main issue is how to overcome limitations of joining with other materials. The present study focuses on solder processing at low operating temperature to avoid exceeding the recrystallization temperature. A feasible joining process for BMG was developed using lead-free solders. The BMG surface is pre-plated with copper, nickel, or titanium as a wetting layer. The reaction temperature is set between the glass transition temperature of BMG and the melting point of the solder. After a reflowing and aging process, the joint sample was examined using SEM, EDS, EPMA, and XRD. The Cu–Zr based BMG can be successfully joined with Sn-58Bi solder after plating Cu on the BMG surface. A diffusion layer was observed and the thickness increased with longer aging time. The main components of the diffusion layer are ZrO2 and Cu10Zr7.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43370136","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}
Hendrata Wibisana, Bangun Muljo Sukotjo, U. Lasminto
Ecosystems in aquatic environments are distinct from ecosystems on land. Changes that occur in ecosystems in aquatic environments affect the lives of biota in these waters, including the fish used as a food source in fishing communities in coastal areas. This study aims to determine the role of remote sensing in mapping and analyzing the relationship between the parameters of sea surface temperature and chlorophyll-a concentrations on the coast. The correlation of sea surface temperature with chlorophyll-a concentrations is modeled via linear regression. An analysis of variance test is performed to establish the suitability of the temperature data for the data on chlorophyll-a concentrations and to map the concentration distribution with the SeaDAS program. Results revealed a linear Chlor (mg/m) = 63,695 − 2,014T (°C) with an R coefficient value of 0.325. This work concludes that Terra MODIS satellite imagery can be used to predict the distribution of chlorophyll-a concentrations on the coast, although its results require further comparison with those of other sensors.
{"title":"Analysis of Correlation and Mapping of Chlorophyll-a Concentrations and Sea Surface Temperatures in Coastal Areas Based on Terra MODIS Satellite Image Data","authors":"Hendrata Wibisana, Bangun Muljo Sukotjo, U. Lasminto","doi":"10.7454/MST.V25I1.3810","DOIUrl":"https://doi.org/10.7454/MST.V25I1.3810","url":null,"abstract":"Ecosystems in aquatic environments are distinct from ecosystems on land. Changes that occur in ecosystems in aquatic environments affect the lives of biota in these waters, including the fish used as a food source in fishing communities in coastal areas. This study aims to determine the role of remote sensing in mapping and analyzing the relationship between the parameters of sea surface temperature and chlorophyll-a concentrations on the coast. The correlation of sea surface temperature with chlorophyll-a concentrations is modeled via linear regression. An analysis of variance test is performed to establish the suitability of the temperature data for the data on chlorophyll-a concentrations and to map the concentration distribution with the SeaDAS program. Results revealed a linear Chlor (mg/m) = 63,695 − 2,014T (°C) with an R coefficient value of 0.325. This work concludes that Terra MODIS satellite imagery can be used to predict the distribution of chlorophyll-a concentrations on the coast, although its results require further comparison with those of other sensors.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43405279","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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