Pub Date : 2022-11-30DOI: 10.5614/j.eng.technol.sci.2022.54.6.4
X. Ge, I. Kolupaev, W. Song, Di Jiang, J. Pu, Hongfeng Wang, Yuan Chu
Friction stir processing (FSP) was used to modify a larger-size surface of H65 copper alloy. The influence of the traverse speed and the rotation speed on the microstructure, the microhardness and the wear resistance of the modified surface were analyzed. The wear mechanism of the modified H65 copper alloy was revealed. The results indicate that the grain size was greatly refined after FSP compared with the parent metal and that the grain size increased with the increment of the rotation speed. The average microhardness of the modified surface was higher than that of the parent metal. The average microhardness had a highest value of 174.13 HV when the traverse speed was 200 mm/min and the rotation speed was 200 rpm, i.e., 21% higher than that of the parent metal. The average microhardness decreased with the increase of the rotation speed. When the traverse speed was 200 mm/min and the rotation speed was 600 rpm, the average friction coefficient of the modified surface was the smallest (0.3213), which was lower than that of the parent metal (0.3810). The wear mechanism of the H65 copper alloy modified by FSP was mainly adhesive wear accompanied by local abrasive wear.
{"title":"Influence of the Process Parameters on the Microhardness and the Wear Resistance of Friction Stir Processed H65 Copper Alloy","authors":"X. Ge, I. Kolupaev, W. Song, Di Jiang, J. Pu, Hongfeng Wang, Yuan Chu","doi":"10.5614/j.eng.technol.sci.2022.54.6.4","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.6.4","url":null,"abstract":"Friction stir processing (FSP) was used to modify a larger-size surface of H65 copper alloy. The influence of the traverse speed and the rotation speed on the microstructure, the microhardness and the wear resistance of the modified surface were analyzed. The wear mechanism of the modified H65 copper alloy was revealed. The results indicate that the grain size was greatly refined after FSP compared with the parent metal and that the grain size increased with the increment of the rotation speed. The average microhardness of the modified surface was higher than that of the parent metal. The average microhardness had a highest value of 174.13 HV when the traverse speed was 200 mm/min and the rotation speed was 200 rpm, i.e., 21% higher than that of the parent metal. The average microhardness decreased with the increase of the rotation speed. When the traverse speed was 200 mm/min and the rotation speed was 600 rpm, the average friction coefficient of the modified surface was the smallest (0.3213), which was lower than that of the parent metal (0.3810). The wear mechanism of the H65 copper alloy modified by FSP was mainly adhesive wear accompanied by local abrasive wear.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43586816","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 : 2022-11-18DOI: 10.5614/j.eng.technol.sci.2022.54.6.1
N. Surajudeen-Bakinde, F. Ehiagwina, A. Afolabi, A. M. Usman
In this research, the suitability of a genetic algorithm (GA) modified Holt-Winters (HW) exponential model for the prediction of spectrum occupancy data was investigated. Firstly, a description of spectrum measurement that was done during a two-week duration at locations (8.511 °N, 4.594 °E) and (8.487 °N, 4.573 °E) of the 900 MHz and 1800 MHz bands is given. In computing the spectrum duty cycle, different decision thresholds per band link were employed due to differing noise levels. A frequency point with a power spectral density less than the decision threshold was considered unoccupied and was assigned a value of 0, while a frequency point with a power spectral density larger than the decision threshold was considered occupied and was assigned a value of 1. Secondly, the spectrum duty cycle was used in the evaluation of the forecast behavior of the forecasting methods. The HW approach uses exponential smoothing to encode the spectrum data and uses them to forecast typical values in present and future states. The mean square error (MSE) of prediction was minimized using a GA by iteratively adjusting the HW discount factors to improve the forecast accuracy. A decrease in MSE of between 8.33 to 44.6% was observed.
{"title":"Genetic Algorithm-Holt-Winters Based Minute Spectrum Occupancy Prediction: An Investigation","authors":"N. Surajudeen-Bakinde, F. Ehiagwina, A. Afolabi, A. M. Usman","doi":"10.5614/j.eng.technol.sci.2022.54.6.1","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.6.1","url":null,"abstract":"In this research, the suitability of a genetic algorithm (GA) modified Holt-Winters (HW) exponential model for the prediction of spectrum occupancy data was investigated. Firstly, a description of spectrum measurement that was done during a two-week duration at locations (8.511 °N, 4.594 °E) and (8.487 °N, 4.573 °E) of the 900 MHz and 1800 MHz bands is given. In computing the spectrum duty cycle, different decision thresholds per band link were employed due to differing noise levels. A frequency point with a power spectral density less than the decision threshold was considered unoccupied and was assigned a value of 0, while a frequency point with a power spectral density larger than the decision threshold was considered occupied and was assigned a value of 1. Secondly, the spectrum duty cycle was used in the evaluation of the forecast behavior of the forecasting methods. The HW approach uses exponential smoothing to encode the spectrum data and uses them to forecast typical values in present and future states. The mean square error (MSE) of prediction was minimized using a GA by iteratively adjusting the HW discount factors to improve the forecast accuracy. A decrease in MSE of between 8.33 to 44.6% was observed.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45739197","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 : 2022-11-18DOI: 10.5614/j.eng.technol.sci.2022.54.6.3
I. Gumilar, Farhan Farohi, Made Munarda, B. Bramanto, G. A. J. Kartini
Three-dimensional (3D) models are indispensable in managing, operating, maintaining, and repairing piping instrumentation activities in oil and gas companies. 3D models are expected to provide more interactive and representative information according to actual objects. Several technologies that can be used to generate piping instrumentation 3D maps are Terrestrial Laser Scanner (TLS) and Handheld 3D Scanner (HS). This study aims to create a 3D model of piping instrumentation using a combination of TLS and HS and analyze the results of data validation used for modeling. The results showed that a 3D modeling of piping instrumentation could be generated accurately using a combination of TLS and HS technologies. Merging between the two data is carried out through a cloud-to-cloud registration process based on the geometry of the object by considering the selection of reference data, the similarity of the scale factor, the unit of measure, and the overlap of the two data. The registration error generated in combining these two methods is less than 0.003 m. The resulting model still has drawbacks, which is the absence of coding for the pipe caused by the unavailability of the Piping and Instrumentation Diagram (P&ID) during modeling. The geometric validation of the model size value using reference data and the field size has the largest absolute difference of 0.0034 m with an average absolute deviation of 0.0016 m.
{"title":"The Combined Use of Terrestrial Laser Scanner and Handheld 3D Scanner for 3D Modeling of Piping Instrumentation at Oil and Gas Company","authors":"I. Gumilar, Farhan Farohi, Made Munarda, B. Bramanto, G. A. J. Kartini","doi":"10.5614/j.eng.technol.sci.2022.54.6.3","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.6.3","url":null,"abstract":"Three-dimensional (3D) models are indispensable in managing, operating, maintaining, and repairing piping instrumentation activities in oil and gas companies. 3D models are expected to provide more interactive and representative information according to actual objects. Several technologies that can be used to generate piping instrumentation 3D maps are Terrestrial Laser Scanner (TLS) and Handheld 3D Scanner (HS). This study aims to create a 3D model of piping instrumentation using a combination of TLS and HS and analyze the results of data validation used for modeling. The results showed that a 3D modeling of piping instrumentation could be generated accurately using a combination of TLS and HS technologies. Merging between the two data is carried out through a cloud-to-cloud registration process based on the geometry of the object by considering the selection of reference data, the similarity of the scale factor, the unit of measure, and the overlap of the two data. The registration error generated in combining these two methods is less than 0.003 m. The resulting model still has drawbacks, which is the absence of coding for the pipe caused by the unavailability of the Piping and Instrumentation Diagram (P&ID) during modeling. The geometric validation of the model size value using reference data and the field size has the largest absolute difference of 0.0034 m with an average absolute deviation of 0.0016 m.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45779214","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 : 2022-11-18DOI: 10.5614/j.eng.technol.sci.2022.54.6.2
T. Dutono, T. Santoso
Several studies have shown that the main challenge in teaching complex systems involving many theoretical backgrounds to senior students is their lack of confidence. In this paper, we present an approach to the teaching methodology of an undergraduate course in a telecommunication study program. The first goal of this methodology is to help students understand the theoretical concepts behind wireless digital communication systems through direct practice to give them more exposure to a real system through affordable practice activities in an experiential context, utilizing an HF radio and a single-board computer (SBC). The second goal is to challenge senior students to understand the data link layer by using white box testing of the syntax of the programming language embedded in the SBC. This approach is ideally carried out based on offline and hands-on class activities, however, the pandemic condition made it unavoidable to do it online using a demonstration model. Feedback from students was collected through written comments, post-testing, including a facility index analysis, and a questionnaire that was distributed using the available e-learning system. The post-test results showed that the average score was 72 out of a maximum of 100.
{"title":"A Low-Cost Laboratory Practice for Fundamental Learning of Wireless Digital Communication","authors":"T. Dutono, T. Santoso","doi":"10.5614/j.eng.technol.sci.2022.54.6.2","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.6.2","url":null,"abstract":"Several studies have shown that the main challenge in teaching complex systems involving many theoretical backgrounds to senior students is their lack of confidence. In this paper, we present an approach to the teaching methodology of an undergraduate course in a telecommunication study program. The first goal of this methodology is to help students understand the theoretical concepts behind wireless digital communication systems through direct practice to give them more exposure to a real system through affordable practice activities in an experiential context, utilizing an HF radio and a single-board computer (SBC). The second goal is to challenge senior students to understand the data link layer by using white box testing of the syntax of the programming language embedded in the SBC. This approach is ideally carried out based on offline and hands-on class activities, however, the pandemic condition made it unavoidable to do it online using a demonstration model. Feedback from students was collected through written comments, post-testing, including a facility index analysis, and a questionnaire that was distributed using the available e-learning system. The post-test results showed that the average score was 72 out of a maximum of 100.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44248875","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 : 2022-09-16DOI: 10.5614/j.eng.technol.sci.2022.54.5.13
A. Raksajati, Hadi Purwanto, A. N. Baskoro, A. Indarto, D. Ariono
Acid gas enrichment unit (AGEU) involves selective separation of H2S from acid gas mixture, for example using absorption with an NaOH solvent solution. Sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) buffer addition to NaOH solution suppresses CO2 absorption, thereby increasing the selectivity of H2S absorption. This study evaluated the effect of buffer addition to increase H2S absorption selectivity using an NaOH solution. It was shown that both buffer addition and L/G ratio decrease could increase H2S selectivity by limiting CO2 absorption. Based on the simulation results, in the 0.006 to 0.030 L/G ratio range and NaOH solvent concentration greater than 2%-mass, the addition of NaHCO3 with mass ratio greater than 1.5:1 to NaOH and the addition of Na2CO3 at 1.26 times NaHCO3’s mass increased H2S absorption selectivity up to 17.3%. The combination of an L/G ratio of 0.006 and solvent with a composition of 5%-mass NaOH, 15%-mass NaHCO3, and 18.9%-mass Na2CO3 produced the highest H2S selectivity of 23.1 (379.7% H2S selectivity increase).
{"title":"Selective H2S Absorption Using the Mixture of NaOH-NaHCO3-Na2CO3 Buffer Solvent Solution","authors":"A. Raksajati, Hadi Purwanto, A. N. Baskoro, A. Indarto, D. Ariono","doi":"10.5614/j.eng.technol.sci.2022.54.5.13","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.5.13","url":null,"abstract":"Acid gas enrichment unit (AGEU) involves selective separation of H2S from acid gas mixture, for example using absorption with an NaOH solvent solution. Sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) buffer addition to NaOH solution suppresses CO2 absorption, thereby increasing the selectivity of H2S absorption. This study evaluated the effect of buffer addition to increase H2S absorption selectivity using an NaOH solution. It was shown that both buffer addition and L/G ratio decrease could increase H2S selectivity by limiting CO2 absorption. Based on the simulation results, in the 0.006 to 0.030 L/G ratio range and NaOH solvent concentration greater than 2%-mass, the addition of NaHCO3 with mass ratio greater than 1.5:1 to NaOH and the addition of Na2CO3 at 1.26 times NaHCO3’s mass increased H2S absorption selectivity up to 17.3%. The combination of an L/G ratio of 0.006 and solvent with a composition of 5%-mass NaOH, 15%-mass NaHCO3, and 18.9%-mass Na2CO3 produced the highest H2S selectivity of 23.1 (379.7% H2S selectivity increase).","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43467143","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 : 2022-09-16DOI: 10.5614/j.eng.technol.sci.2022.54.5.14
L. Ernawati, R. Wahyuono, A. Halim, N. Widiastuti, Audi Sabrina, Kurnia Handayani
Groundwater highly contaminated with organic substances and heavy metal ions in the Kariangau Industrial Area, Balikpapan, East Kalimantan is indicated by the comparatively high COD. Therefore, the technology for treating wastewater to remove various toxins before releasing it into the environment needs to be advanced. Here, we present a green synthetic method of a composite adsorbent (SF/SS) using soursop seeds and silkworm cocoons. SEM, FTIR, and BET were used to analyze the physicochemical characteristics of the adsorbent. Mechanistic investigation of the SF/SS adsorbent performance for the removal of Cu2+ metal ions and crystal violet (CV) was conducted, while taking into account variables affecting adsorption properties. The Freundlich and Langmuir isotherm adsorption models were used to fit the adsorption equilibrium, while pseudo-first and second-order models were used to assess the adsorption kinetics. The mesoporous SF/SS adsorbent exhibited the highest adsorption capacities of 78.6 and 69.2 mg‧g-1, respectively. The pseudo-first model showed the best fit for CV removal with a kinetic rate of 0.0634 min-1, while the Freundlich model exhibited the best fitting for both of CV and Cu2+ removal. The results showed that SF/SS can be applied as an efficient adsorbent for both of heavy metal and organic dye removal.
{"title":"Silk Fibroin/Soursop Seed Bio-Adsorbent for Crystal Violet and Copper Metal Ion Removal","authors":"L. Ernawati, R. Wahyuono, A. Halim, N. Widiastuti, Audi Sabrina, Kurnia Handayani","doi":"10.5614/j.eng.technol.sci.2022.54.5.14","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.5.14","url":null,"abstract":"Groundwater highly contaminated with organic substances and heavy metal ions in the Kariangau Industrial Area, Balikpapan, East Kalimantan is indicated by the comparatively high COD. Therefore, the technology for treating wastewater to remove various toxins before releasing it into the environment needs to be advanced. Here, we present a green synthetic method of a composite adsorbent (SF/SS) using soursop seeds and silkworm cocoons. SEM, FTIR, and BET were used to analyze the physicochemical characteristics of the adsorbent. Mechanistic investigation of the SF/SS adsorbent performance for the removal of Cu2+ metal ions and crystal violet (CV) was conducted, while taking into account variables affecting adsorption properties. The Freundlich and Langmuir isotherm adsorption models were used to fit the adsorption equilibrium, while pseudo-first and second-order models were used to assess the adsorption kinetics. The mesoporous SF/SS adsorbent exhibited the highest adsorption capacities of 78.6 and 69.2 mg‧g-1, respectively. The pseudo-first model showed the best fit for CV removal with a kinetic rate of 0.0634 min-1, while the Freundlich model exhibited the best fitting for both of CV and Cu2+ removal. The results showed that SF/SS can be applied as an efficient adsorbent for both of heavy metal and organic dye removal.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49114669","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 : 2022-09-15DOI: 10.5614/j.eng.technol.sci.2022.54.5.9
Buragadda Kiran Kumar, V. C. Das
Wire Electric Discharge Machining (WEDM) is a non-traditional machining method that is widely used in the manufacture of aerospace/aircraft and medical equipment for conductive materials. WEDM products are expected to have good dimensional accuracy, surface roughness, and geometry. Many researchers have done experiments on various materials to optimize the process, which has many parameters and response characteristics. This paper provides an overview of the WEDM process on alloy steels in order to understand the impact of input process variables on output responses and optimization techniques for selecting optimal process parameters. This paper also highlights WEDM process trends as well as workpiece materials, wire varieties, wire diameters, and optimization approaches. This work is expected to be useful in initiating further research on WEDM by documenting substantial research works confirming the latest scenario.
{"title":"Perspective and Prospects of Wire Electric Discharge Machining (WEDM)","authors":"Buragadda Kiran Kumar, V. C. Das","doi":"10.5614/j.eng.technol.sci.2022.54.5.9","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.5.9","url":null,"abstract":"Wire Electric Discharge Machining (WEDM) is a non-traditional machining method that is widely used in the manufacture of aerospace/aircraft and medical equipment for conductive materials. WEDM products are expected to have good dimensional accuracy, surface roughness, and geometry. Many researchers have done experiments on various materials to optimize the process, which has many parameters and response characteristics. This paper provides an overview of the WEDM process on alloy steels in order to understand the impact of input process variables on output responses and optimization techniques for selecting optimal process parameters. This paper also highlights WEDM process trends as well as workpiece materials, wire varieties, wire diameters, and optimization approaches. This work is expected to be useful in initiating further research on WEDM by documenting substantial research works confirming the latest scenario.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44639738","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 : 2022-09-15DOI: 10.5614/j.eng.technol.sci.2022.54.5.12
Mutiara Fajar, Emenda Sembiring, M. Handajani
Microplastics (MP) can pose a serious threat to the environment and human health because of their tiny size and ability to spread easily in water. One of the alternative treatments to remove MP from water is the rapid sand filter (RSF). The objective of this study was to analyze the effects of filter media size and loading rate on RSF performance in removing MP. The applied filter media was silica sand with effective sizes (ES) of 0.39 and 0.68 mm. The loading rates of filtration were 4; 6; 8 and 10 m3/m2-h. The MP samples were made from plastic bags and torn tires (artificial samples: 10 to 800 µm). This study showed that the MP removal percentage was up to 96.6% (MP size larger than 200 µm). The head loss increment for loading rates 4; 6; 8; 10 m3/m2-h was 0.16; 0.35; 0.34; 0.25 m (ES 0.39 m) and 0.10; 0.18; 0.18; 0.19 m (ES 0.68 m)), respectively. Meanwhile, the filtration cycle for loading rates 4; 6; 8; and 10 m3/m2-h was 5, 2, 2, and 1 days (ES 0.39 mm) and 9, 4, 3, and 3 days (ES 0.68 mm), respectively. The result of this study showed that the smaller the filter media size, the higher the head loss of the filter media bed. Furthermore, there is an increased head loss of the filter media bed when the loading rate is greater.
{"title":"The Effect of Filter Media Size and Loading Rate to Filter Performance of Removing Microplastics using Rapid Sand Filter","authors":"Mutiara Fajar, Emenda Sembiring, M. Handajani","doi":"10.5614/j.eng.technol.sci.2022.54.5.12","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.5.12","url":null,"abstract":"Microplastics (MP) can pose a serious threat to the environment and human health because of their tiny size and ability to spread easily in water. One of the alternative treatments to remove MP from water is the rapid sand filter (RSF). The objective of this study was to analyze the effects of filter media size and loading rate on RSF performance in removing MP. The applied filter media was silica sand with effective sizes (ES) of 0.39 and 0.68 mm. The loading rates of filtration were 4; 6; 8 and 10 m3/m2-h. The MP samples were made from plastic bags and torn tires (artificial samples: 10 to 800 µm). This study showed that the MP removal percentage was up to 96.6% (MP size larger than 200 µm). The head loss increment for loading rates 4; 6; 8; 10 m3/m2-h was 0.16; 0.35; 0.34; 0.25 m (ES 0.39 m) and 0.10; 0.18; 0.18; 0.19 m (ES 0.68 m)), respectively. Meanwhile, the filtration cycle for loading rates 4; 6; 8; and 10 m3/m2-h was 5, 2, 2, and 1 days (ES 0.39 mm) and 9, 4, 3, and 3 days (ES 0.68 mm), respectively. The result of this study showed that the smaller the filter media size, the higher the head loss of the filter media bed. Furthermore, there is an increased head loss of the filter media bed when the loading rate is greater.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47170953","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 : 2022-09-15DOI: 10.5614/j.eng.technol.sci.2022.54.5.10
Muhaned Zaidi
Two bulk-driven CMOS (Complementary Metal Oxide Semiconductor) operational amplifier (op-amp) designs for electrocardiogram (ECG) application are presented and compared in this paper. Both op-amps are based on two-stage amplification, where bulk-driven differential input is the first stage, while additional DC gain is the second stage. Different compensation techniques were integrated in each op-amp design. Standard Miller compensation was used for the first op-amp parallel with the second stage. The novelty of the second op-amp is that it utilizes negative Miller compensation between the bulk-driven input node and the output node of the first stag, while standard Miller compensation was used in the second stage. The purpose of this work was to compare DC gain, phase margin (PM) and unit gain frequency (UGF) obtained through different simulated compensation strategies and test results. The op-amps were simulated using 0.25 μm CMOS technology. The simulation results are presented using the standard model libraries from Tanner EDA tools, operating on a single rail +0.8V power supply.
{"title":"Low-voltage Low-power Bulk-driven CMOS Op-Amp Using Negative Miller Compensation for ECG","authors":"Muhaned Zaidi","doi":"10.5614/j.eng.technol.sci.2022.54.5.10","DOIUrl":"https://doi.org/10.5614/j.eng.technol.sci.2022.54.5.10","url":null,"abstract":"Two bulk-driven CMOS (Complementary Metal Oxide Semiconductor) operational amplifier (op-amp) designs for electrocardiogram (ECG) application are presented and compared in this paper. Both op-amps are based on two-stage amplification, where bulk-driven differential input is the first stage, while additional DC gain is the second stage. Different compensation techniques were integrated in each op-amp design. Standard Miller compensation was used for the first op-amp parallel with the second stage. The novelty of the second op-amp is that it utilizes negative Miller compensation between the bulk-driven input node and the output node of the first stag, while standard Miller compensation was used in the second stage. The purpose of this work was to compare DC gain, phase margin (PM) and unit gain frequency (UGF) obtained through different simulated compensation strategies and test results. The op-amps were simulated using 0.25 μm CMOS technology. The simulation results are presented using the standard model libraries from Tanner EDA tools, operating on a single rail +0.8V power supply.","PeriodicalId":15689,"journal":{"name":"Journal of Engineering and Technological Sciences","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46316865","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 : 2022-09-15DOI: 10.5614/j.eng.technol.sci.2022.54.5.8
Muhammad Ihsan Abyan, A. Nuryaman, B. Jihad, Soleh Junjunan, A. Asmiati
A rocket is a spacecraft, guided missile, or flying vehicle that boosted by a chemical reaction resulting from the combustion of propellant in the rocket motor. One of the essential parameters in the development of rocket motors is design optimization to improve the propulsion performance of the rocket. Increasing the propulsion performance of the rocket will increase the flight performance of the rocket, in terms of its maximum range or the altitude of the rocket trajectory. This study examined the determination of the design parameter values of a rocket motor by looking at it as an optimization problem with constraints. The problem studied was limited to the case of the second-stage rocket motor. A genetic algorithm was used to solve the resulting optimization problem of propellant grain configuration cases and a characteristic method for designing the bell nozzle. The results obtained indicated an increase in total impulse by 10% compared to the results before optimization.
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