{"title":"Briquette of Empty Fruit Bunch Fiber as an Alternative Substitution for Binderless Fuel Methods","authors":"","doi":"10.7454/mst.v27i3.1455","DOIUrl":"https://doi.org/10.7454/mst.v27i3.1455","url":null,"abstract":"","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"32 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139161810","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}
{"title":"Effect of Lime Content, Curing Temperature, and Aging Condition on Low-Alkaline Concrete","authors":"","doi":"10.7454/mst.v27i3.1527","DOIUrl":"https://doi.org/10.7454/mst.v27i3.1527","url":null,"abstract":"","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"11 6","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139163029","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}
{"title":"Optimization of the Building Envelope and Roof Shading to Reduce the Energy Consumption of College Low-Rise Buildings in Indonesia","authors":"","doi":"10.7454/mst.v27i3.1435","DOIUrl":"https://doi.org/10.7454/mst.v27i3.1435","url":null,"abstract":"","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"13 5","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139161377","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}
{"title":"Heat Transfer Enhancement in Nanofluid Flows Augmented by Magnetic Flux","authors":"","doi":"10.7454/mst.v27i3.1618","DOIUrl":"https://doi.org/10.7454/mst.v27i3.1618","url":null,"abstract":"","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"67 3","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139162241","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}
{"title":"Isolation and Characterization of Caffeine-Degrading Bacteria from Coffee Plantation Areas in Malaysia","authors":"","doi":"10.7454/mst.v27i3.1462","DOIUrl":"https://doi.org/10.7454/mst.v27i3.1462","url":null,"abstract":"","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"15 5","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139162321","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}
Reverse logistics social responsibility is preferred as the most acceptable solution for addressing the challenges in stakeholders’ debate regarding social responsibility in supply chains because it involves as many actors as possible in the supply chain to perform social responsibility to achieve sustainability. This paper explores the challenges in achieving optimal policies in sustainability dimensions for collection and recycling facilities in reverse logistics. Sustainability dimensions include economic, environmental, and social aspects. The reverse logistics is modeled on System Dynamics, and a simplified statistical analysis using a contour chart is employed in numerical experiments. Results show a narrow area of optimal solutions in contour charts for policy parameter settings to realize sustainability. Therefore, this paper finds that optimization of reverse logistics to develop sustainability is a highly challenging task for policy makers. Therefore, managers must carefully study their policies before implementation to avoid unnecessary and less optimal performance in the sustainability dimensions.
{"title":"Challenges in Optimization for the Performance on Sustainability Dimensions in Reverse Logistics Social Responsibility","authors":"","doi":"10.7454/mst.v27i2.1445","DOIUrl":"https://doi.org/10.7454/mst.v27i2.1445","url":null,"abstract":"Reverse logistics social responsibility is preferred as the most acceptable solution for addressing the challenges in stakeholders’ debate regarding social responsibility in supply chains because it involves as many actors as possible in the supply chain to perform social responsibility to achieve sustainability. This paper explores the challenges in achieving optimal policies in sustainability dimensions for collection and recycling facilities in reverse logistics. Sustainability dimensions include economic, environmental, and social aspects. The reverse logistics is modeled on System Dynamics, and a simplified statistical analysis using a contour chart is employed in numerical experiments. Results show a narrow area of optimal solutions in contour charts for policy parameter settings to realize sustainability. Therefore, this paper finds that optimization of reverse logistics to develop sustainability is a highly challenging task for policy makers. Therefore, managers must carefully study their policies before implementation to avoid unnecessary and less optimal performance in the sustainability dimensions.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036811","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}
Optical relaying is the best technique to implement free-space optical (FSO) communications as a terrestrial platform. However, atmospheric turbulence (AT) limits the optical-propagation path length. In this study, the implementation of some optical amplifiers (OAs) in cascaded configuration, namely, erbium-doped fiber amplifiers, semiconductor OAs, and Raman amplifiers (RAs), are investigated through simulation. This study aims to search for the maximum link distance of an optical propagation and enhance the FSO performance caused by each configuration of OAs. The optical relaying network consists of three nodes, with each node designed with a space of several kilometers under the influence of AT. At the end of the destination, before the receiver, an optical band-pass filter is applied to perform noise filtering. Among the OAs in the cascaded configuration, the RA can expand the link distance of the optical-propagation path length to a range of 14.7–15.9 Km under the influence of a strong AT. The signal-to-noise ratio and bit error rate of the system are in the ranges of 24.1– 19.08 dB and 7.9 × 10−15–7.4 × 10−6, respectively.
{"title":"The Relaying Network in Free-Space Optical Communications using Optical Amplifiers in Cascaded Configuration","authors":"","doi":"10.7454/mst.v27i2.1583","DOIUrl":"https://doi.org/10.7454/mst.v27i2.1583","url":null,"abstract":"Optical relaying is the best technique to implement free-space optical (FSO) communications as a terrestrial platform. However, atmospheric turbulence (AT) limits the optical-propagation path length. In this study, the implementation of some optical amplifiers (OAs) in cascaded configuration, namely, erbium-doped fiber amplifiers, semiconductor OAs, and Raman amplifiers (RAs), are investigated through simulation. This study aims to search for the maximum link distance of an optical propagation and enhance the FSO performance caused by each configuration of OAs. The optical relaying network consists of three nodes, with each node designed with a space of several kilometers under the influence of AT. At the end of the destination, before the receiver, an optical band-pass filter is applied to perform noise filtering. Among the OAs in the cascaded configuration, the RA can expand the link distance of the optical-propagation path length to a range of 14.7–15.9 Km under the influence of a strong AT. The signal-to-noise ratio and bit error rate of the system are in the ranges of 24.1– 19.08 dB and 7.9 × 10−15–7.4 × 10−6, respectively.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036812","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 study explores axisymmetric endwall contouring with emphasis on the design of novel endwalls capable of heat load reduction. Optimizations with parameterization numerically determined by the endwall of flat shape led to the endwall of the contoured shape with substantial depletion of heat transfer in the passage of the vane. Heat transfer attributes for the generated contoured endwalls were analyzed for the exit Reynolds number of 2 × 106 . Endwall three-dimensional contouring resulted in remarkable changes in secondary flow vortices, jet-to-secondary flow interaction, and film cooling effectiveness on the flat endwall. The results pointed out that the axisymmetric convergent contouring causes a significant increase in endwall film cooling, especially for the hard-to-cooled regions throughout the vane, but the level of benefit is significantly affected by the blowing ratios. The obtained efficacy demonstrated the flow impact of the cross-passage on the proliferation of the coolant on top of the flat endwall and the amenability for jet lift-off at elevated blowing ratios. The optimal mass flow rate selection of the current work could identify the passage of the endwall, contoured with superior axial turbine efficiency and durability than that of the flat endwall.
{"title":"Accomplishments of Endwall Contouring on Heat Transfer in a Passage of a Turbine Blade","authors":"","doi":"10.7454/mst.v27i2.1617","DOIUrl":"https://doi.org/10.7454/mst.v27i2.1617","url":null,"abstract":"The study explores axisymmetric endwall contouring with emphasis on the design of novel endwalls capable of heat load reduction. Optimizations with parameterization numerically determined by the endwall of flat shape led to the endwall of the contoured shape with substantial depletion of heat transfer in the passage of the vane. Heat transfer attributes for the generated contoured endwalls were analyzed for the exit Reynolds number of 2 × 106 . Endwall three-dimensional contouring resulted in remarkable changes in secondary flow vortices, jet-to-secondary flow interaction, and film cooling effectiveness on the flat endwall. The results pointed out that the axisymmetric convergent contouring causes a significant increase in endwall film cooling, especially for the hard-to-cooled regions throughout the vane, but the level of benefit is significantly affected by the blowing ratios. The obtained efficacy demonstrated the flow impact of the cross-passage on the proliferation of the coolant on top of the flat endwall and the amenability for jet lift-off at elevated blowing ratios. The optimal mass flow rate selection of the current work could identify the passage of the endwall, contoured with superior axial turbine efficiency and durability than that of the flat endwall.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036818","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}
This research was conducted with the aim of investigating the use of waste carpet fiber (WCF) and assessing the resistance properties of concrete. The main goal of this study was to investigate the effect of the internal processing of concrete containing WCF on increasing its resistance properties. At the same time, the secondary goals pursued in the research included determining the optimal percentages of carpet fibers in improving compressive strength, tensile strength, and bending strength. The materials used included cement, aggregates, water, WCF, and super lubricant. This research applied seven mixing designs: A, B1, B2, C1, C2, D1, and D2. Mixing plan A was the control plan. Sample B1 contained 2.45 kg/m3 of WCF and 40 kg/m3 of lyca for processing, while sample B2 contained 2.45 kg/m3 of WCF and no lyca. Sample C1 contained 35.7 kg/m3 of WCF and 80 kg/m3 of lyca for processing, sample C2 contained 35.7 kg/m3 of WCF and no lyca, Sample D1 contained 12.25 kg/m3 of WCF and 120 kg/m3 of lyca for processing, and sample D2 contained 12.25 kg/m3 of WCF and no lyca. The results showed that the use of waste carpet fibers and processing by lyca reduced the compressive strength of the samples. The results of the tensile strength test revealed that the use of waste carpet fibers along with processing by lyca increased the tensile strength of the samples. Finally, the flexural strength test results showed that the use of small amounts of WCF and lyca treatment led to an increase in the flexural strength of concrete.
{"title":"Investigating the Resistance Properties of Concrete Containing Waste Carpet Fibers","authors":"","doi":"10.7454/mst.v27i2.1616","DOIUrl":"https://doi.org/10.7454/mst.v27i2.1616","url":null,"abstract":"This research was conducted with the aim of investigating the use of waste carpet fiber (WCF) and assessing the resistance properties of concrete. The main goal of this study was to investigate the effect of the internal processing of concrete containing WCF on increasing its resistance properties. At the same time, the secondary goals pursued in the research included determining the optimal percentages of carpet fibers in improving compressive strength, tensile strength, and bending strength. The materials used included cement, aggregates, water, WCF, and super lubricant. This research applied seven mixing designs: A, B1, B2, C1, C2, D1, and D2. Mixing plan A was the control plan. Sample B1 contained 2.45 kg/m3 of WCF and 40 kg/m3 of lyca for processing, while sample B2 contained 2.45 kg/m3 of WCF and no lyca. Sample C1 contained 35.7 kg/m3 of WCF and 80 kg/m3 of lyca for processing, sample C2 contained 35.7 kg/m3 of WCF and no lyca, Sample D1 contained 12.25 kg/m3 of WCF and 120 kg/m3 of lyca for processing, and sample D2 contained 12.25 kg/m3 of WCF and no lyca. The results showed that the use of waste carpet fibers and processing by lyca reduced the compressive strength of the samples. The results of the tensile strength test revealed that the use of waste carpet fibers along with processing by lyca increased the tensile strength of the samples. Finally, the flexural strength test results showed that the use of small amounts of WCF and lyca treatment led to an increase in the flexural strength of concrete.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136241810","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}
Permeability is a soil parameter related to the construction industry to understand the processes of infiltration, runoff, and settlement. The risk of testing errors is inevitable in permeability investigations, especially in expansive soils. Trial and error in permeability testing becomes difficult due to soils with small pore sizes and large shrinkage expansion. Several studies related to soil physical properties that affect permeability have been conducted. However, the correlation results obtained still have poor accuracy. Artificial neural networks (ANN) are machine learning systems that can change their structure to solve problems that are included in the system. The use of ANNs in data learning is applied to help the established model predict future output values with a small error value. This research aims to study the correlation between the physical properties of expansive soil that affect its permeability using ANN correlation and then produce correlation equations for future inputs. The research was conducted with input data in the form of soil liquid limit, soil plasticity index (IP), %fine grains, and soil permeability as output data. Results demonstrated a good correlation between soil physical properties and permeability, revealing high accuracy in the output regression equation.
{"title":"Permeability Prediction for Expansive Soil Based on Physical Properties Using Artificial Neural Networks","authors":"","doi":"10.7454/mst.v27i2.1623","DOIUrl":"https://doi.org/10.7454/mst.v27i2.1623","url":null,"abstract":"Permeability is a soil parameter related to the construction industry to understand the processes of infiltration, runoff, and settlement. The risk of testing errors is inevitable in permeability investigations, especially in expansive soils. Trial and error in permeability testing becomes difficult due to soils with small pore sizes and large shrinkage expansion. Several studies related to soil physical properties that affect permeability have been conducted. However, the correlation results obtained still have poor accuracy. Artificial neural networks (ANN) are machine learning systems that can change their structure to solve problems that are included in the system. The use of ANNs in data learning is applied to help the established model predict future output values with a small error value. This research aims to study the correlation between the physical properties of expansive soil that affect its permeability using ANN correlation and then produce correlation equations for future inputs. The research was conducted with input data in the form of soil liquid limit, soil plasticity index (IP), %fine grains, and soil permeability as output data. Results demonstrated a good correlation between soil physical properties and permeability, revealing high accuracy in the output regression equation.","PeriodicalId":42980,"journal":{"name":"Makara Journal of Technology","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136241809","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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