Pub Date : 2022-12-01DOI: 10.31185/ejuow.vol10.iss3.336
Yahya M. Abbas, Ali A. F. Al-Hamadani
In concentrated solar energy applications, the Stirling engine is the optimum option for extracting mechanical work. The engine's most notable features are minimal noise, vibration, and pollution, as well as its capacity to function with any external heat source, including biomass, solar energy, and industrial waste. The gamma-type STE-1008 Stirling engine is the subject of our research. This engine can handle a maximum charging pressure of 10 bar. The engine is divided into two sections (expansion and compression) and three heat exchangers (regenerator, cooler, and heater). The cooler is a finned aluminium heat exchanger with 144 internal fins, each with a cross-sectional area of 1 mm by 10 mm. The regenerator is fitted with a diameter of 31 m and a volumetric porosity of 90%. This investigation employed a random fiber with three different metals: stainless steel, copper, and aluminium. Nitrogen and air served as the working fluids. From the results, stainless steel, copper, and aluminium regenerators produced 583 W, 562 W, and 553 W, respectively. When nitrogen is utilized at 500 °C, the engine generates 11 N.m of torque compared to 8.5 N.m when air is used, and the engine has a thermal efficiency of 19% compared to 15% when air is used. The results of other researchers were used to compare and validate our model. With errors of no more than 12%, the results were close enough to the experimental data to be useful.
{"title":"The Influence of the working fluid and Regenerator material on the Performance of the types Gamma Stirling Engine","authors":"Yahya M. Abbas, Ali A. F. Al-Hamadani","doi":"10.31185/ejuow.vol10.iss3.336","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss3.336","url":null,"abstract":"In concentrated solar energy applications, the Stirling engine is the optimum option for extracting mechanical work. The engine's most notable features are minimal noise, vibration, and pollution, as well as its capacity to function with any external heat source, including biomass, solar energy, and industrial waste. The gamma-type STE-1008 Stirling engine is the subject of our research. This engine can handle a maximum charging pressure of 10 bar. The engine is divided into two sections (expansion and compression) and three heat exchangers (regenerator, cooler, and heater). The cooler is a finned aluminium heat exchanger with 144 internal fins, each with a cross-sectional area of 1 mm by 10 mm. The regenerator is fitted with a diameter of 31 m and a volumetric porosity of 90%. This investigation employed a random fiber with three different metals: stainless steel, copper, and aluminium. Nitrogen and air served as the working fluids. From the results, stainless steel, copper, and aluminium regenerators produced 583 W, 562 W, and 553 W, respectively. When nitrogen is utilized at 500 °C, the engine generates 11 N.m of torque compared to 8.5 N.m when air is used, and the engine has a thermal efficiency of 19% compared to 15% when air is used. The results of other researchers were used to compare and validate our model. With errors of no more than 12%, the results were close enough to the experimental data to be useful.","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124844464","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 : 2022-11-20DOI: 10.31185/ejuow.vol10.iss3.384
Ola Najman, Zina K. Kadhim, K. Khalaf
In this paper, the improvement of heat exchange in a compact heat exchanger that is used in the automotive cooling system is numerically studied due to the importance that this part of the automotive represents in removing the heat generated in the automotive engine. The study adopted CFD simulation to introduce a new design of radiator that included changing the geometry and material of the tube while maintaining the same cross-section area In addition, the study also included replacing the shape of the fins from the louver to plain fin with the increase in the number of tubes. The study used a water-Ethylene glycol mixture (50:50) as a hot fluid with four flow rates (10, 12, 18, 24) l/h, (75, 85, 95) °C inlet temperature, and air as a cold fluid with 1.5, 2.5, 4.5, 5.5) m/s and (35) °C inlet temperature. Through the results obtained, the designed model appeared to have a higher thermal performance than the standard model due to the material and shape of the tube and fins. The designed model performed well, achieving an improvement ratio of (18.6%) for the heat transfer rate, (13.8%) for the overall heat transfer coefficient for the hot fluid, and (29.8%) for the air-side heat transfer coefficient
{"title":"Numerical investigation on Enhancing Heating performance in Automotive Radiator","authors":"Ola Najman, Zina K. Kadhim, K. Khalaf","doi":"10.31185/ejuow.vol10.iss3.384","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss3.384","url":null,"abstract":"In this paper, the improvement of heat exchange in a compact heat exchanger that is used in the automotive cooling system is numerically studied due to the importance that this part of the automotive represents in removing the heat generated in the automotive engine. The study adopted CFD simulation to introduce a new design of radiator that included changing the geometry and material of the tube while maintaining the same cross-section area In addition, the study also included replacing the shape of the fins from the louver to plain fin with the increase in the number of tubes. The study used a water-Ethylene glycol mixture (50:50) as a hot fluid with four flow rates (10, 12, 18, 24) l/h, (75, 85, 95) °C inlet temperature, and air as a cold fluid with 1.5, 2.5, 4.5, 5.5) m/s and (35) °C inlet temperature. Through the results obtained, the designed model appeared to have a higher thermal performance than the standard model due to the material and shape of the tube and fins. The designed model performed well, achieving an improvement ratio of (18.6%) for the heat transfer rate, (13.8%) for the overall heat transfer coefficient for the hot fluid, and (29.8%) for the air-side heat transfer coefficient","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133516902","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 : 2022-11-03DOI: 10.31185/ejuow.vol10.iss3.386
Dr.Manaf K Hussein
The development of machine learning strategies has made it possible to diagnose some disease automatically based on data obtained from medical imaging. Brain age is one of the factors that can be used as an indicator of cognitive well-being. Recent advancements in machine learning have made it possible for computers to anticipate classification and prediction outcomes more accurately than humans. In this study, five widely used machine learning regression models (Linear support vector regression (L-SVR), radial basis function support vector regression (RBF-SVR), relevance vector regression (RVR), Elastic Net and Gaussian process regression (GPR)) were trained and evaluated to predict brain age using volumes of brain regions data. Moreover, a dimensionality reduction technique was utilized to reduce the dimensionality of the input feature space. The data were collected from one hundred and eleven participants. The results showed no performance difference amongst models trained on the same type of data, suggesting that the type of input data had a stronger influence on prediction performance than the model choice. The experimental results indicated that the GPR was the best fit model (R2=0.57, R=0.75) among the other regression models while the G-SVR was the worst fit model (R2=0.0006, R=0.025) with such number of the input data.
{"title":"Comparison of various machine learning regression models based on Human age prediction","authors":"Dr.Manaf K Hussein","doi":"10.31185/ejuow.vol10.iss3.386","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss3.386","url":null,"abstract":"The development of machine learning strategies has made it possible to diagnose some disease automatically based on data obtained from medical imaging. Brain age is one of the factors that can be used as an indicator of cognitive well-being. Recent advancements in machine learning have made it possible for computers to anticipate classification and prediction outcomes more accurately than humans.\u0000In this study, five widely used machine learning regression models (Linear support vector regression (L-SVR), radial basis function support vector regression (RBF-SVR), relevance vector regression (RVR), Elastic Net and Gaussian process regression (GPR)) were trained and evaluated to predict brain age using volumes of brain regions data. Moreover, a dimensionality reduction technique was utilized to reduce the dimensionality of the input feature space. The data were collected from one hundred and eleven participants.\u0000The results showed no performance difference amongst models trained on the same type of data, suggesting that the type of input data had a stronger influence on prediction performance than the model choice. The experimental results indicated that the GPR was the best fit model (R2=0.57, R=0.75) among the other regression models while the G-SVR was the worst fit model (R2=0.0006, R=0.025) with such number of the input data. ","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130757009","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 : 2022-10-22DOI: 10.31185/ejuow.vol10.iss2.303
Jasim Khalid, Alaa R. Al-Badry
Researchers have been motivating by the global warming challenge to develop alternatives substances to compounds that contribute to this problem. The refrigerant R134a (HFC134a) has been identified as one of the most environmentally damaging gases. As a result, the refrigerant R1234yf has been employed in air conditioning systems as a substitute to the refrigerant R134a. The condensation heat transfer coefficient (HTC) of the refrigerants R1234yf and R134a was measured on smooth and standard finned tubes in this study. The finned tube is characterized by 32 Fins per inch (FPI) and 1 mm fin height. The condensation process was investigated at 37°C and 40°C condensing temperatures and 16°C to 28°C water inlet temperatures. The Nusselt theory accurately predicted the condensation HTCs on the smooth tube within mean absolute percentage deviation (MAPD) of 5.3% for R134a and 4.7% for R1234yf. As the wall sub-cooling increases, the condensation HTC decreases. With a drop in LMTD, the overall heat transfer coefficient (HTC) rises. For finned tube, the refrigerant R134a showed a greater HTC than R1234yf. In comparison to smooth tube, the enhancement ratio in HTC was 78% at 37 and 82% at 40°C for R134a. The enhancement ratio with R1234yf was 65% and 81% at 37 and 40 ° C, respectively. The experimental data was compared with predictions of two previous analytical models for film condensation on finned tubes.
{"title":"FILM –WISE CONDENSATION OF R1234yf AND R134a REFRIGERANTS ON FINNED TUBE WITH 32 FINS PER INCH","authors":"Jasim Khalid, Alaa R. Al-Badry","doi":"10.31185/ejuow.vol10.iss2.303","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.303","url":null,"abstract":"Researchers have been motivating by the global warming challenge to develop alternatives substances to compounds that contribute to this problem. The refrigerant R134a (HFC134a) has been identified as one of the most environmentally damaging gases. As a result, the refrigerant R1234yf has been employed in air conditioning systems as a substitute to the refrigerant R134a. The condensation heat transfer coefficient (HTC) of the refrigerants R1234yf and R134a was measured on smooth and standard finned tubes in this study. The finned tube is characterized by 32 Fins per inch (FPI) and 1 mm fin height. The condensation process was investigated at 37°C and 40°C condensing temperatures and 16°C to 28°C water inlet temperatures. The Nusselt theory accurately predicted the condensation HTCs on the smooth tube within mean absolute percentage deviation (MAPD) of 5.3% for R134a and 4.7% for R1234yf. As the wall sub-cooling increases, the condensation HTC decreases. With a drop in LMTD, the overall heat transfer coefficient (HTC) rises. For finned tube, the refrigerant R134a showed a greater HTC than R1234yf. In comparison to smooth tube, the enhancement ratio in HTC was 78% at 37 and 82% at 40°C for R134a. The enhancement ratio with R1234yf was 65% and 81% at 37 and 40 ° C, respectively. The experimental data was compared with predictions of two previous analytical models for film condensation on finned tubes.","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116418981","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 : 2022-10-22DOI: 10.31185/ejuow.vol10.iss2.304
Rusul Fadhil, Ismail Sh. Hburi, Hassanein Fleih, Mayes M. Taher, Hasan F. Khazaal
An Image with high-resolution is associated with huge size data space because each information of the image is arranged into 2D picture elements' values, each of them containing its associated value of the RGB bits. The depiction of picture data makes it challenging to distribute picture files using the Internet. For Internet users, the time it takes to upload and download photos has all time been the main concern. A high-resolution image takes up more storage space, in addition to the data transit difficulty. The Analysis of Principal Component, or PCA for a brief notation, is a mathematical approach utilized to lessen the data dimensionality. It extracts the main pattern of a linear system using the factoring matrices technique. The objectives of this paper are to see how effective PCA is in reducing digital picture features and to investigate the (feature-reduced) images’ quality on comparison with different values of the variance. As per the synthesizing of the initial research, the dimension or size reduction technique through the Analysis of Principal Component typically involves of 4-important steps: (1) picture-data normalizing (2) matrix of the covariance calculating using picture-data. (3) discovering the picture-data projection (with fewer number of features) to a new basis use the Single Value Decomposition technique (SVD) (4) determining the picture-data projection (with fewer number of characteristics) to a new basis. According to testing results, the PCA approach considerably decreases the size of picture data while sustaining the original picture’s fundamental properties. This approach reduced file size by 35.3 percent for the best feature lowered quality. The upload time of picture files through the Internet has substantially improved, particularly for mobile device downloads.
{"title":"Digital-Image Dimension Reduction Via Analysis of Principal component","authors":"Rusul Fadhil, Ismail Sh. Hburi, Hassanein Fleih, Mayes M. Taher, Hasan F. Khazaal","doi":"10.31185/ejuow.vol10.iss2.304","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.304","url":null,"abstract":"An Image with high-resolution is associated with huge size data space because each information of the image is arranged into 2D picture elements' values, each of them containing its associated value of the RGB bits. The depiction of picture data makes it challenging to distribute picture files using the Internet. For Internet users, the time it takes to upload and download photos has all time been the main concern. A high-resolution image takes up more storage space, in addition to the data transit difficulty. The Analysis of Principal Component, or PCA for a brief notation, is a mathematical approach utilized to lessen the data dimensionality. It extracts the main pattern of a linear system using the factoring matrices technique. The objectives of this paper are to see how effective PCA is in reducing digital picture features and to investigate the (feature-reduced) images’ quality on comparison with different values of the variance. As per the synthesizing of the initial research, the dimension or size reduction technique through the Analysis of Principal Component typically involves of 4-important steps: (1) picture-data normalizing (2) matrix of the covariance calculating using picture-data. (3) discovering the picture-data projection (with fewer number of features) to a new basis use the Single Value Decomposition technique (SVD) (4) determining the picture-data projection (with fewer number of characteristics) to a new basis. According to testing results, the PCA approach considerably decreases the size of picture data while sustaining the original picture’s fundamental properties. This approach reduced file size by 35.3 percent for the best feature lowered quality. The upload time of picture files through the Internet has substantially improved, particularly for mobile device downloads.","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"77 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120838030","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 : 2022-08-01DOI: 10.31185/ejuow.vol10.iss2.285
Dr. Naser Zedin
Aluminum-magnesium-silicon alloys are widely used in wide rage of engineering applications because they have moderate corrosion resistance, excellent formability, and high specific strength. The combined effect of quenching media and aging time on corrosion behavior, mechanical properties, and microstructure of 6061 Al alloy was investigated. Potentiodynamic polarization technique was employed to study the corrosion behavior of 6061 Al alloy in 3.5 %NaCl solution. The microstructure, phases and mechanical properties were examined via optical microscope, XRD and tensile and hardness testers respectively. The results of microstructure and X-ray diffraction analyses showed that the formation of (CuAl2) and (Mg2Si) phases improved the hardness and strength. The mechanical properties and corrosion resistance of treated 6061 Al alloy were progressively increased with increasing aging time.
{"title":"Effect of quenching treatment on corrosion behavior and mechanical properties of 6061 aluminum alloy","authors":"Dr. Naser Zedin","doi":"10.31185/ejuow.vol10.iss2.285","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.285","url":null,"abstract":"Aluminum-magnesium-silicon alloys are widely used in wide rage of engineering applications because they have moderate corrosion resistance, excellent formability, and high specific strength. The combined effect of quenching media and aging time on corrosion behavior, mechanical properties, and microstructure of 6061 Al alloy was investigated. Potentiodynamic polarization technique was employed to study the corrosion behavior of 6061 Al alloy in 3.5 %NaCl solution. The microstructure, phases and mechanical properties were examined via optical microscope, XRD and tensile and hardness testers respectively. The results of microstructure and X-ray diffraction analyses showed that the formation of (CuAl2) and (Mg2Si) phases improved the hardness and strength. The mechanical properties and corrosion resistance of treated 6061 Al alloy were progressively increased with increasing aging time.","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133922684","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 : 2022-08-01DOI: 10.31185/ejuow.vol10.iss2.248
A. Mohammad, A. Al-Bayati
Despite of the economic advantages provided by the voided slabs, their design against punching shear failure, as suggested by the current building codes, are based on the equations derived from tests on flat slabs. Previous tests on voided slabs showed that the punching shear capacity of such slabs are different from that of flat slabs due to the differences in cross-sections. This paper reviews the previous works conducted to investigate the punching shear behavior of voided slabs. In addition, it evaluates the punching shear design provisions of the current building codes using the test results of voided slabs from literature. It was found that the punching shear design equations of the current building codes are inconsistent when they applied to estimate the punching shear capacities of voided slabs
{"title":"Punching Shear Strength of Voided Slab: Literature Review and Evaluation of Design Codes","authors":"A. Mohammad, A. Al-Bayati","doi":"10.31185/ejuow.vol10.iss2.248","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.248","url":null,"abstract":"Despite of the economic advantages provided by the voided slabs, their design against punching shear failure, as suggested by the current building codes, are based on the equations derived from tests on flat slabs. Previous tests on voided slabs showed that the punching shear capacity of such slabs are different from that of flat slabs due to the differences in cross-sections. This paper reviews the previous works conducted to investigate the punching shear behavior of voided slabs. In addition, it evaluates the punching shear design provisions of the current building codes using the test results of voided slabs from literature. It was found that the punching shear design equations of the current building codes are inconsistent when they applied to estimate the punching shear capacities of voided slabs","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134433924","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 : 2022-08-01DOI: 10.31185/ejuow.vol10.iss2.267
Tabarek Hussein, Ismael Sharhan Haburi
Non-Orthogonal Multiple Access (NOMA) is a possible multiple access option for the coming generation of wireless communications that has a higher SE and takes advantage of network resource reuse. As a result, academic and industry researchers have recently looked into the error performance and capacity of NOMA schemes. Because of the non-orthogonal nature of NOMA technique, the main disadvantage is users’ interference, which is normally mitigated using interference cancellation techniques such as Successive Interference Cancellation (SIC) at the receivers. In this paper, we investigate the performance of NOMA and the power allocation strategy utilized on BER. We used BASK modulation with Rayleigh fading channel and AWGN channel. The numerical results show that NOMA works well in equal and different distances between users.
{"title":"BER Performance for Downlink NOMA","authors":"Tabarek Hussein, Ismael Sharhan Haburi","doi":"10.31185/ejuow.vol10.iss2.267","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.267","url":null,"abstract":"Non-Orthogonal Multiple Access (NOMA) is a possible multiple access option for the coming generation of wireless communications that has a higher SE and takes advantage of network resource reuse. As a result, academic and industry researchers have recently looked into the error performance and capacity of NOMA schemes. Because of the non-orthogonal nature of NOMA technique, the main disadvantage is users’ interference, which is normally mitigated using interference cancellation techniques such as Successive Interference Cancellation (SIC) at the receivers. In this paper, we investigate the performance of NOMA and the power allocation strategy utilized on BER. We used BASK modulation with Rayleigh fading channel and AWGN channel. The numerical results show that NOMA works well in equal and different distances between users.","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123766077","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 : 2022-08-01DOI: 10.31185/ejuow.vol10.iss2.409
Raad A. Al-Ameri, M. Özakça, Esra Eylem Karataş, M. Tolga Göğüş, A. Hamza Tanrıkulu
Despite that concrete is a fire-resisting construction material, its microstructure suffers significant chemical and physical changes when subjected to temperatures higher than 400 oC. Therefore, the combined effect of unexpected impacts and fire can lead to the collapse of the structure. To evaluate this combined effect, an experimental program was directed in this study using the ACI 544-2R repeated impact test method. Shallow cylindrical specimens with 150 mm diameter and 64 mm depth were prepared to evaluate the cracking and failure impact strengths of normal strength concrete (NC) and engineered cementitious composites (ECC). The ECC mixture was reinforced with 2% of polypropylene fibers. In addition to the impact strength, the compressive and flexural strengths of NC and ECC mixtures were also investigated. The impact, compressive and flexural tests were performed on unheated specimens and others heated to 500 oC to evaluate the residual strengths of NC and ECC mixtures. The results showed that before heating, ECC exhibited a failure impact performance that is approximately 6 times more ductile than that of NC, where the retained failure impact numbers of NC and ECC were 57 and 259 blows, respectively. However, both mixtures lost approximately 95% of their impact strengths after exposure to 500 oC.
{"title":"Drop-Weight Impact Tests on Engineered Cementitious Composites heated to 500 oC","authors":"Raad A. Al-Ameri, M. Özakça, Esra Eylem Karataş, M. Tolga Göğüş, A. Hamza Tanrıkulu","doi":"10.31185/ejuow.vol10.iss2.409","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.409","url":null,"abstract":"Despite that concrete is a fire-resisting construction material, its microstructure suffers significant chemical and physical changes when subjected to temperatures higher than 400 oC. Therefore, the combined effect of unexpected impacts and fire can lead to the collapse of the structure. To evaluate this combined effect, an experimental program was directed in this study using the ACI 544-2R repeated impact test method. Shallow cylindrical specimens with 150 mm diameter and 64 mm depth were prepared to evaluate the cracking and failure impact strengths of normal strength concrete (NC) and engineered cementitious composites (ECC). The ECC mixture was reinforced with 2% of polypropylene fibers. In addition to the impact strength, the compressive and flexural strengths of NC and ECC mixtures were also investigated. The impact, compressive and flexural tests were performed on unheated specimens and others heated to 500 oC to evaluate the residual strengths of NC and ECC mixtures. The results showed that before heating, ECC exhibited a failure impact performance that is approximately 6 times more ductile than that of NC, where the retained failure impact numbers of NC and ECC were 57 and 259 blows, respectively. However, both mixtures lost approximately 95% of their impact strengths after exposure to 500 oC. ","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115599864","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 : 2022-08-01DOI: 10.31185/ejuow.vol10.iss2.341
A. Al-Waaly, A. S. Hameed, Rusul K. Edam
Finite volume analysis of two-dimensional model has been performed to study of the influence of heat flux and mass flux on two phase heat transfer through microchannel during water flow boiling. The channel dimensions were (5×5××50) m3. The inlet boundary conditions were (1.63, 3.32, 4.9, 6.65, 8.16) . The supplied heat fluxes were 24.8 , 33.2 , 46.13 , 51 and 69 for nucleate boiling while 33.3 , 50 , 66.7 , 83.3 , and 100 for dryout condition. The inlet temperature was 30oC. It was shown that the highest heat transfer coefficient occurs at beginning of onset of nucleate boiling (ONB) after that the it will drop due the changing of the flow patterns. According to supplied heat flux, the patterns were bubble flow, dispersed bubbles, churn flow, annular flow, and then dry out condition occurs. For the mass flux 1.63kg/ the highest heat transfer coefficient was 9.5 kW/ while for the mass flux 8.16 kg/ the highest heat transfer coefficient was 20kW/ . For the mass flux 1.63kg/ the highest value of vapour quality was 0.09 while for the mass flux 8.16 kg/ the highest value was 0.15. There is a sharp pressure drop when starts to nucleate and the highest value occurs at dryout condition. This study gave an understanding of the heat exchange flow behaviour during water boiling through a single microchannel.
{"title":"Flow Instability of a Liquid Through a Small-Scale Channel During a Flow Evaporation","authors":"A. Al-Waaly, A. S. Hameed, Rusul K. Edam","doi":"10.31185/ejuow.vol10.iss2.341","DOIUrl":"https://doi.org/10.31185/ejuow.vol10.iss2.341","url":null,"abstract":"Finite volume analysis of two-dimensional model has been performed to study of the influence of heat flux and mass flux on two phase heat transfer through microchannel during water flow boiling. The channel dimensions were (5×5××50) m3. The inlet boundary conditions were (1.63, 3.32, 4.9, 6.65, 8.16) . The supplied heat fluxes were 24.8 , 33.2 , 46.13 , 51 and 69 for nucleate boiling while 33.3 , 50 , 66.7 , 83.3 , and 100 for dryout condition. The inlet temperature was 30oC. It was shown that the highest heat transfer coefficient occurs at beginning of onset of nucleate boiling (ONB) after that the it will drop due the changing of the flow patterns. According to supplied heat flux, the patterns were bubble flow, dispersed bubbles, churn flow, annular flow, and then dry out condition occurs. For the mass flux 1.63kg/ the highest heat transfer coefficient was 9.5 kW/ while for the mass flux 8.16 kg/ the highest heat transfer coefficient was 20kW/ . For the mass flux 1.63kg/ the highest value of vapour quality was 0.09 while for the mass flux 8.16 kg/ the highest value was 0.15. There is a sharp pressure drop when starts to nucleate and the highest value occurs at dryout condition. This study gave an understanding of the heat exchange flow behaviour during water boiling through a single microchannel.","PeriodicalId":184256,"journal":{"name":"Wasit Journal of Engineering Sciences","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131856029","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：