Sabah Fartosy, Narmeen Abdalwahhab Abdalqadir, Haider Ali Al-Mussawy, Nagham Qasim Jafar, Soumya Ghosh
Concrete is utilized in a wide range of civil engineering applications specifically in infrastructure projects. In general, as with any construction material, it may be subjected to deterioration over time because of various reasons such as excessive loading and so on. In this research, two reinforced concrete beams on a large scale (length 2400 mm, depth 350 mm, and width 250 mm) are cast and tested under static load using the ultrasonic pulse velocity (UPV) technique consisting of three pairs of transducers (54 kHz, 150 kHz, and 250 kHz). During the loading, the signals are sent and captured through the used transducers at selected loading steps. Two new proposed procedures based on signal peaks in time and frequency domains are used to monitor the crack progress induced in concrete beams under concentrated load. The findings of this study revealed the suitability of the proposed two approaches to detect the propagation of cracks to evaluate damage induced in concrete beams.
{"title":"A COMBINED ULTRASONIC PROCEDURE TO EVALUATE DAMAGE IN CONCRETE BEAMS SUBJECTED TO STATIC LOAD","authors":"Sabah Fartosy, Narmeen Abdalwahhab Abdalqadir, Haider Ali Al-Mussawy, Nagham Qasim Jafar, Soumya Ghosh","doi":"10.31272/jeasd.28.2.5","DOIUrl":"https://doi.org/10.31272/jeasd.28.2.5","url":null,"abstract":"Concrete is utilized in a wide range of civil engineering applications specifically in infrastructure projects. In general, as with any construction material, it may be subjected to deterioration over time because of various reasons such as excessive loading and so on. In this research, two reinforced concrete beams on a large scale (length 2400 mm, depth 350 mm, and width 250 mm) are cast and tested under static load using the ultrasonic pulse velocity (UPV) technique consisting of three pairs of transducers (54 kHz, 150 kHz, and 250 kHz). During the loading, the signals are sent and captured through the used transducers at selected loading steps. Two new proposed procedures based on signal peaks in time and frequency domains are used to monitor the crack progress induced in concrete beams under concentrated load. The findings of this study revealed the suitability of the proposed two approaches to detect the propagation of cracks to evaluate damage induced in concrete beams.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"108 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140088457","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}
Due to partial shading effects on the productivity of solar panels which in turn negatively impacts the performance characteristics of photovoltaic systems, researchers work on different studies to overcome this phenomenon and improve solar system productivity. Therefore, this study aims to investigate different techniques to enhance the output power, fill factor, and efficiency of the PV system by reducing the number of local maximum power peaks, power losses, and mismatch losses. The configurations include a novel static reconfiguration technique, called a Screw Horizontal photovoltaic array, and a recently developed technique known as a Bridge Linkage array. Both of these are modeled using MATLAB/Simulink software and examined during six shading patterns. The novelty of this study is that we combined the above static reconfiguration technique with another modern technique called blocking and bypass diode technology to prevent the effect of reverse current and hotspot phenomena respectively. According to the results, the Bridge Linkage configuration performs the most efficiently under partial shading conditions compared to the Screw horizontal PV array configuration.
{"title":"PERFORMANCE OF SCREW HORIZONTAL AND BRIDGE LINKAGE PHOTOVOLTAIC ARRAY CONFIGURATIONS","authors":"Mohammed Osamah Subhi, Wafaa Saeed Majeed","doi":"10.31272/jeasd.28.2.9","DOIUrl":"https://doi.org/10.31272/jeasd.28.2.9","url":null,"abstract":"Due to partial shading effects on the productivity of solar panels which in turn negatively impacts the performance characteristics of photovoltaic systems, researchers work on different studies to overcome this phenomenon and improve solar system productivity. Therefore, this study aims to investigate different techniques to enhance the output power, fill factor, and efficiency of the PV system by reducing the number of local maximum power peaks, power losses, and mismatch losses. The configurations include a novel static reconfiguration technique, called a Screw Horizontal photovoltaic array, and a recently developed technique known as a Bridge Linkage array. Both of these are modeled using MATLAB/Simulink software and examined during six shading patterns. The novelty of this study is that we combined the above static reconfiguration technique with another modern technique called blocking and bypass diode technology to prevent the effect of reverse current and hotspot phenomena respectively. According to the results, the Bridge Linkage configuration performs the most efficiently under partial shading conditions compared to the Screw horizontal PV array configuration.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":" 941","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140092017","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}
Rusul Abdul Rahim Ghadban, Mohammed Ali Abdulrehman
This study examined the feasibility of producing colored geopolymer concrete using slag as the binder and investigated the effects of pigment on various properties of geopolymer concrete. The geopolymer concrete was supplemented with two varieties of pigment, namely iron oxide hydroxide in the shades of "red" and "yellow", then the following tests of compressive strength, rebound number, density, and ultrasonic pulse velocity were carried out on it. The highest compressive strength value was achieved when adding 1% of pigments, which increased the red and yellow values from the reference value by 2.7 percent and 1.8 percent, respectively. The best rebound number values can be obtained by adding 1% yellow and 3% red, which increased the red and yellow values from the reference value by 8% and 15%, respectively. The density increases as the proportion of the additional pigment rises. The maximum density values were achieved by incorporating 1% of red and yellow pigment, with a respective increase of 1% and 3% for red and yellow. The highest values of ultrasonic pulse velocity when adding 1% of yellow and red color pigments increased by 1.7% for yellow and 2% for red. The optimal addition is 1.2% as it enhances properties and reduces expenses when utilizing smaller pigments.
{"title":"EFFECT OF ADDING RED AND YELLOW PIGMENTS TO GEOPOLYMER CONCRETE","authors":"Rusul Abdul Rahim Ghadban, Mohammed Ali Abdulrehman","doi":"10.31272/jeasd.28.2.6","DOIUrl":"https://doi.org/10.31272/jeasd.28.2.6","url":null,"abstract":"This study examined the feasibility of producing colored geopolymer concrete using slag as the binder and investigated the effects of pigment on various properties of geopolymer concrete. The geopolymer concrete was supplemented with two varieties of pigment, namely iron oxide hydroxide in the shades of \"red\" and \"yellow\", then the following tests of compressive strength, rebound number, density, and ultrasonic pulse velocity were carried out on it. The highest compressive strength value was achieved when adding 1% of pigments, which increased the red and yellow values from the reference value by 2.7 percent and 1.8 percent, respectively. The best rebound number values can be obtained by adding 1% yellow and 3% red, which increased the red and yellow values from the reference value by 8% and 15%, respectively. The density increases as the proportion of the additional pigment rises. The maximum density values were achieved by incorporating 1% of red and yellow pigment, with a respective increase of 1% and 3% for red and yellow. The highest values of ultrasonic pulse velocity when adding 1% of yellow and red color pigments increased by 1.7% for yellow and 2% for red. The optimal addition is 1.2% as it enhances properties and reduces expenses when utilizing smaller pigments.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"106 49","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140088625","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}
Concepts of evolution theory (by Herbert Spencer) were analyzed using a Geographic Information System according to living notions in the context of an urban city. The idea of the theory was applied to the society within the context of Balad city to find out whether the concepts of contrast, integration, specialization, and exclusivity on which the theory is based have an impact on the services in the city and an effect on the structure of the social elements and the stages of its development. The research problem centered on the shortcomings of the theory in predicting and explaining the morphological and functional structure of the city, while the main objective is to analyze the concepts of biological theory according to the requirements of the context of the study area. The analysis results of the living context notions present in the city were compared with the urban housing standards using GIS to determine the extent to which the context conforms to the concept of Spencer's theory. The research found the inability of the biological side of the theory to explain the population concentration in residential neighborhoods, as well as the lack of reliance on the concepts of contrast and integration in predicting the reasons for the growth and expansion of the city, and that the city neighborhoods showed a variance in their services without showing integration and exclusivity in these services, that is, the lack of integration organic between the biological parts of the city.
{"title":"URBAN CONTEXT ANALYSIS ACCORDING TO THE CONCEPT OF SPENCER'S BIOLOGICAL THEORY USING GIS: BALAD CITY CASE STUDY","authors":"Ali Dhafer Abed, Nuridah Binti Sabtu","doi":"10.31272/jeasd.28.2.4","DOIUrl":"https://doi.org/10.31272/jeasd.28.2.4","url":null,"abstract":"Concepts of evolution theory (by Herbert Spencer) were analyzed using a Geographic Information System according to living notions in the context of an urban city. The idea of the theory was applied to the society within the context of Balad city to find out whether the concepts of contrast, integration, specialization, and exclusivity on which the theory is based have an impact on the services in the city and an effect on the structure of the social elements and the stages of its development. The research problem centered on the shortcomings of the theory in predicting and explaining the morphological and functional structure of the city, while the main objective is to analyze the concepts of biological theory according to the requirements of the context of the study area. The analysis results of the living context notions present in the city were compared with the urban housing standards using GIS to determine the extent to which the context conforms to the concept of Spencer's theory. The research found the inability of the biological side of the theory to explain the population concentration in residential neighborhoods, as well as the lack of reliance on the concepts of contrast and integration in predicting the reasons for the growth and expansion of the city, and that the city neighborhoods showed a variance in their services without showing integration and exclusivity in these services, that is, the lack of integration organic between the biological parts of the city.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":" 607","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140092509","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}
Samer Saad Abbas, R. M. Raouf, Harith H. Al-Moameri
Epoxy resins have been the subject of many studies as a consequence of their extensive usage in recent years. The brittleness and low resistance to propagation and crack initiation of epoxy resins are well-recognized characteristics. Therefore, in recent years, experts have concentrated on increasing epoxy resin's fracture resistance. Adding inorganic nanoparticles like titanium dioxide (TiO2) TiO2, silica (SiO2), carbon black, alumina (Al2O3), and others to the polymer matrix is one of the most investigated techniques in polymer science. Despite having a modest nanofiller content, the resulting nanocomposites may enhance their thermal, mechanical, rheological, electrical, and optical characteristics. These nanocomposites are an alternative to metal-based materials. They have great promise as multifunctional materials in a range of applications, including optoelectronic devices, semiconductor devices, civil engineering, automotive, and aerospace. To show potential future directions and market prospects for polymer nanocomposites reinforced with TiO2 nanoparticles, current results, and trends have been examined and highlighted. In addition, the current review surveys many studies that highlighted using nanoparticles as reinforcement, their different structure, the interface, and the geometry and structure of the resulting nano-materials reinforced resin.
{"title":"A REVIEW OF EPOXY-NANOCOMPOSITE PROPERTIES","authors":"Samer Saad Abbas, R. M. Raouf, Harith H. Al-Moameri","doi":"10.31272/jeasd.28.1.6","DOIUrl":"https://doi.org/10.31272/jeasd.28.1.6","url":null,"abstract":"Epoxy resins have been the subject of many studies as a consequence of their extensive usage in recent years. The brittleness and low resistance to propagation and crack initiation of epoxy resins are well-recognized characteristics. Therefore, in recent years, experts have concentrated on increasing epoxy resin's fracture resistance. Adding inorganic nanoparticles like titanium dioxide (TiO2) TiO2, silica (SiO2), carbon black, alumina (Al2O3), and others to the polymer matrix is one of the most investigated techniques in polymer science. Despite having a modest nanofiller content, the resulting nanocomposites may enhance their thermal, mechanical, rheological, electrical, and optical characteristics. These nanocomposites are an alternative to metal-based materials. They have great promise as multifunctional materials in a range of applications, including optoelectronic devices, semiconductor devices, civil engineering, automotive, and aerospace. To show potential future directions and market prospects for polymer nanocomposites reinforced with TiO2 nanoparticles, current results, and trends have been examined and highlighted. In addition, the current review surveys many studies that highlighted using nanoparticles as reinforcement, their different structure, the interface, and the geometry and structure of the resulting nano-materials reinforced resin.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"47 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126837","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}
Zainab M. Shukur, R. Neamah, Husam Jawad Abdulsamad, L. S. Al-Ansari, Sutartip Wittayapiyanon
Beams in two configurations; uniform and non-uniform, are common structural components utilized for several engineering applications. Thus, the studies dealing with their behavior under dynamic and vibrations have been increased. In this research, the transverse vibration phenomena of pre-twisted beams were experimentally and theoretically studied by investigating the effect of twisting angles on the first three transverse natural frequencies. In the present experimental part, the pre-twisted beams are manufactured using a 3D printer, and the fundamental frequencies of manufactured pre-twisted beams are measured by a suitable rig. In the theoretical work, the finite element method is used to simulate the transverse vibration behavior of the pre-twisted beams. The accuracy of the simulation process is checked by comparison of the first natural frequencies calculated by the finite element method (using ANSYS Workbench Software) with those measured experimentally. The results show that there is an excellent agreement between the experimental results and finite element outputs. For the clamped-free pre-twisted beam, there is no critical twisting angle. The critical twisting angle is equal to the mode number for simply – simply and clamped simple pre-twisted beam. While there is more than one value of critical twisting angle for the clamped-clamped pre-twisted beam.
梁有均匀和非均匀两种结构，是多种工程应用中常用的结构部件。因此，对其动态和振动行为的研究也越来越多。在本研究中，通过研究扭转角对前三个横向自然频率的影响，对预扭转梁的横向振动现象进行了实验和理论研究。在本实验部分，使用 3D 打印机制造了预扭曲梁，并通过合适的钻机测量了制造的预扭曲梁的基频。在理论工作中，采用有限元法模拟预扭曲梁的横向振动行为。通过比较有限元法（使用 ANSYS Workbench 软件）计算的第一固有频率和实验测量的第一固有频率，检验了模拟过程的准确性。结果表明，实验结果与有限元输出结果非常吻合。对于无夹具预扭梁，不存在临界扭转角。对于简单预扭梁和夹紧简单预扭梁，临界扭转角等于模数。而有夹具预扭梁的临界扭转角有多个值。
{"title":"CALCULATING THE NATURAL FREQUENCY OF PRE-TWISTED BEAM","authors":"Zainab M. Shukur, R. Neamah, Husam Jawad Abdulsamad, L. S. Al-Ansari, Sutartip Wittayapiyanon","doi":"10.31272/jeasd.28.1.1","DOIUrl":"https://doi.org/10.31272/jeasd.28.1.1","url":null,"abstract":"Beams in two configurations; uniform and non-uniform, are common structural components utilized for several engineering applications. Thus, the studies dealing with their behavior under dynamic and vibrations have been increased. In this research, the transverse vibration phenomena of pre-twisted beams were experimentally and theoretically studied by investigating the effect of twisting angles on the first three transverse natural frequencies. In the present experimental part, the pre-twisted beams are manufactured using a 3D printer, and the fundamental frequencies of manufactured pre-twisted beams are measured by a suitable rig. In the theoretical work, the finite element method is used to simulate the transverse vibration behavior of the pre-twisted beams. The accuracy of the simulation process is checked by comparison of the first natural frequencies calculated by the finite element method (using ANSYS Workbench Software) with those measured experimentally. The results show that there is an excellent agreement between the experimental results and finite element outputs. For the clamped-free pre-twisted beam, there is no critical twisting angle. The critical twisting angle is equal to the mode number for simply – simply and clamped simple pre-twisted beam. While there is more than one value of critical twisting angle for the clamped-clamped pre-twisted beam.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"27 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139125790","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}
In this article, a triple-band patch antenna using a circular patch microstrip antenna is constructed with a low-profile patch antenna using a 1.5 mm thick FR4 substrate (εr= 4.3). As mobile devices like smartphones and laptops become more common, the usage of tiny, triple-band antennas has also become more common. The objective of this research is to design a circular patch antenna with a 3–11 GHz dipole-like radiation pattern, which may be used for industrial, scientific, and medical reasons. For the suggested triple-band antenna design, the slotted radiator with six arches and the reduction of the ground plane are among the components. In addition, the standard 50 Ω RF transmission line stimulates the patch antenna; this transmission line is attached to the microstrip line by an impedance-compliant SMA connection. Data from the experiments are obtained, evaluated, and compared; to the patch's surface current distributions, gain, and radiation patterns. According to the measurements, S11 has an impedance bandwidth in the 5.5 GHz band of less than -10 dB, 6.6 GHz band, and 10.4 GHz band at all frequencies. The superb radiation pattern performance, relatively consistent gain throughout the bands, and practical bandwidths of this antenna make it a good choice for C-band and dual X-band applications.
本文使用 1.5 毫米厚的 FR4 基板（εr= 4.3），利用圆形贴片微带天线和扁平贴片天线构建了三频贴片天线。随着智能手机和笔记本电脑等移动设备的普及，微型三频天线的使用也越来越普遍。本研究的目的是设计一种具有 3-11 GHz 类偶极子辐射模式的圆形贴片天线，可用于工业、科学和医疗领域。在建议的三频天线设计中，六个拱形的开槽辐射器和地平面的缩小是其中的组成部分。此外，标准 50 Ω 射频传输线激励贴片天线；该传输线通过阻抗兼容的 SMA 连接与微带线相连。实验数据的获取、评估和比较涉及贴片的表面电流分布、增益和辐射模式。根据测量结果，S11 在 5.5 GHz 频段、6.6 GHz 频段和 10.4 GHz 频段的阻抗带宽均小于-10 dB。该天线出色的辐射模式性能、各频段相对稳定的增益以及实用的带宽使其成为 C 波段和双 X 波段应用的理想选择。
{"title":"TRIPLE-BAND CIRCULAR PATCH MICROSTRIP ANTENNA FOR WIRELESS COMMUNICATION","authors":"Abeer Khalid Nghaimesh, Ali Khalid Jassim","doi":"10.31272/jeasd.28.1.5","DOIUrl":"https://doi.org/10.31272/jeasd.28.1.5","url":null,"abstract":"In this article, a triple-band patch antenna using a circular patch microstrip antenna is constructed with a low-profile patch antenna using a 1.5 mm thick FR4 substrate (εr= 4.3). As mobile devices like smartphones and laptops become more common, the usage of tiny, triple-band antennas has also become more common. The objective of this research is to design a circular patch antenna with a 3–11 GHz dipole-like radiation pattern, which may be used for industrial, scientific, and medical reasons. For the suggested triple-band antenna design, the slotted radiator with six arches and the reduction of the ground plane are among the components. In addition, the standard 50 Ω RF transmission line stimulates the patch antenna; this transmission line is attached to the microstrip line by an impedance-compliant SMA connection. Data from the experiments are obtained, evaluated, and compared; to the patch's surface current distributions, gain, and radiation patterns. According to the measurements, S11 has an impedance bandwidth in the 5.5 GHz band of less than -10 dB, 6.6 GHz band, and 10.4 GHz band at all frequencies. The superb radiation pattern performance, relatively consistent gain throughout the bands, and practical bandwidths of this antenna make it a good choice for C-band and dual X-band applications.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"28 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126286","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 provides an experimental study for preparing eco-friendly geopolymer mortar based on ground granulated blasted furnace slags with good mechanical properties and durability. This work studied the effect of silica fume reactive powder as a replacement material for slag weight with constant weight ratios of 20% on geopolymer mortar’s mechanical tests. The geopolymer mixtures were prepared with (15M) NaOH solution and a (2.5:1) ratio of (Na2SiO3/NaOH). The samples were cured at ambient conditions at different times of 7 and 28 days and a high temperature of 70°C in a furnace for three hours. It was found from the obtained results that silica fume played a vital role in improving all these properties by enhancing the degree of the silicate ion geopolymerization reaction in the alkaline solution. In addition, the curing process greatly impacted the geopolymers’ features. The properties improve significantly with increasing the curing time and temperature, especially when cured at high temperatures, compared to ambient curing.
{"title":"CURING CONDITIONS IMPACT THE PROPERTIES OF A MODIFIED GEOPOLYMER MORTAR","authors":"Rusul Jabbar, H. Kamal","doi":"10.31272/jeasd.28.1.10","DOIUrl":"https://doi.org/10.31272/jeasd.28.1.10","url":null,"abstract":"The present work provides an experimental study for preparing eco-friendly geopolymer mortar based on ground granulated blasted furnace slags with good mechanical properties and durability. This work studied the effect of silica fume reactive powder as a replacement material for slag weight with constant weight ratios of 20% on geopolymer mortar’s mechanical tests. The geopolymer mixtures were prepared with (15M) NaOH solution and a (2.5:1) ratio of (Na2SiO3/NaOH). The samples were cured at ambient conditions at different times of 7 and 28 days and a high temperature of 70°C in a furnace for three hours. It was found from the obtained results that silica fume played a vital role in improving all these properties by enhancing the degree of the silicate ion geopolymerization reaction in the alkaline solution. In addition, the curing process greatly impacted the geopolymers’ features. The properties improve significantly with increasing the curing time and temperature, especially when cured at high temperatures, compared to ambient curing.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"16 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126333","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}
In recent years, Fiber Reinforced Polymer (FRP) rebar has been adopted to reinforce structural concrete elements such as slabs. FRP strips are also increasingly used to reinforce or strengthen concrete members that require higher carrying capacity or to restore damaged structural elements. Therefore, the reinforcement of concrete structures with this material is increasing but the effect of variables on CFRP-reinforced concrete slabs and externally bonded with CFRP laminates has not been evaluated in detail. This study presents a numerical analysis of the structural performance of concrete slabs reinforced by CFRP bars and strengthened by CFRP laminates using a finite element approach with ANSYS software. Six models with the same geometry (1550x1550x100 mm) were analyzed. Four models were reinforced with CFRP bars and externally strengthened with CFRP laminates, one model was reinforced with CFRP bars without external strength, and one reference model with traditional reinforcing bars (control specimen). Different parameters were adopted, such as amounts of FRP bars and CFRP laminates layout in which some models contained both CFRP bars and CFRP laminates. A uniformly distributed load that was calculated by plastic analysis was applied at the top surface area of each model. The plastic load considers the contribution of the laminated CFRP strips that increased the strength of the slab. Analysis results in the maximum strength carrying capacity in equivalent CFRP bars exhibit higher strength percentages of 5.07% of load capacity but differed in mode of failure than conventional reinforcements control slab.
{"title":"PERFORMANCE OF CONCRETE SLAB REINFORCED BY CFRP BARS AND STRENGTHENED BY DIFFERENT LAYOUT OF CFRP LAMINATES","authors":"Entidhar Najm Abed, M. Medhlom","doi":"10.31272/jeasd.28.1.9","DOIUrl":"https://doi.org/10.31272/jeasd.28.1.9","url":null,"abstract":"In recent years, Fiber Reinforced Polymer (FRP) rebar has been adopted to reinforce structural concrete elements such as slabs. FRP strips are also increasingly used to reinforce or strengthen concrete members that require higher carrying capacity or to restore damaged structural elements. Therefore, the reinforcement of concrete structures with this material is increasing but the effect of variables on CFRP-reinforced concrete slabs and externally bonded with CFRP laminates has not been evaluated in detail. This study presents a numerical analysis of the structural performance of concrete slabs reinforced by CFRP bars and strengthened by CFRP laminates using a finite element approach with ANSYS software. Six models with the same geometry (1550x1550x100 mm) were analyzed. Four models were reinforced with CFRP bars and externally strengthened with CFRP laminates, one model was reinforced with CFRP bars without external strength, and one reference model with traditional reinforcing bars (control specimen). Different parameters were adopted, such as amounts of FRP bars and CFRP laminates layout in which some models contained both CFRP bars and CFRP laminates. A uniformly distributed load that was calculated by plastic analysis was applied at the top surface area of each model. The plastic load considers the contribution of the laminated CFRP strips that increased the strength of the slab. Analysis results in the maximum strength carrying capacity in equivalent CFRP bars exhibit higher strength percentages of 5.07% of load capacity but differed in mode of failure than conventional reinforcements control slab.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"116 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126157","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}
Assim Hameed Yousif Al Daraje, Afrah Awad, Mohamed Gogazeh, Hanan Afeef Mohammad Khamees
Air impact processes have diverse applications in engineering, including backflow welding, textile drying, and gas turbine blade and combustion liner cooling. This research examines the influence of experimental methodologies and measurement tools on convective heat transfer in adjustable air jet assemblies. The experiment involves the use of heated targets made of thin stainless steel foil with constant heat flux boundary conditions. Thermography measures target surface temperatures by analyzing how internal passage cross-flow affects convective heat transfer via outflow adjustments. The experiments involve two arrays of jet nozzles: inline and staggering, each comprising 44 impingement jet nozzles arranged in 4 rows with 11 jet holes in each row. The study presents unsteady time average local and spatial Nusselt numbers as functions of jet Reynolds number (4630-14000) and explores their dependence on the jet nozzle diameter. Cross-flow levels significantly affect spatial and local Nusselt numbers in both local and span-wise averaged values, regardless of the Reynolds number. Strong cross-flow (single configuration) distributes flow causing turbulence and uneven heat distribution, reducing Nusselt numbers. In contrast, moderate cross-flow (double configuration) improves heat transfer and increases Nusselt numbers. The study emphasizes the crucial role of experimental techniques in heat transfer evaluation and demonstrates agreement with prior studies within a standard error below 5%.
{"title":"IMPACT OF MEASUREMENTS TECHNIQUES ON HEAT TRANSFER CHARACTERISTICS IN AIR JET ARRAYS","authors":"Assim Hameed Yousif Al Daraje, Afrah Awad, Mohamed Gogazeh, Hanan Afeef Mohammad Khamees","doi":"10.31272/jeasd.28.1.2","DOIUrl":"https://doi.org/10.31272/jeasd.28.1.2","url":null,"abstract":"Air impact processes have diverse applications in engineering, including backflow welding, textile drying, and gas turbine blade and combustion liner cooling. This research examines the influence of experimental methodologies and measurement tools on convective heat transfer in adjustable air jet assemblies. The experiment involves the use of heated targets made of thin stainless steel foil with constant heat flux boundary conditions. Thermography measures target surface temperatures by analyzing how internal passage cross-flow affects convective heat transfer via outflow adjustments. The experiments involve two arrays of jet nozzles: inline and staggering, each comprising 44 impingement jet nozzles arranged in 4 rows with 11 jet holes in each row. The study presents unsteady time average local and spatial Nusselt numbers as functions of jet Reynolds number (4630-14000) and explores their dependence on the jet nozzle diameter. Cross-flow levels significantly affect spatial and local Nusselt numbers in both local and span-wise averaged values, regardless of the Reynolds number. Strong cross-flow (single configuration) distributes flow causing turbulence and uneven heat distribution, reducing Nusselt numbers. In contrast, moderate cross-flow (double configuration) improves heat transfer and increases Nusselt numbers. The study emphasizes the crucial role of experimental techniques in heat transfer evaluation and demonstrates agreement with prior studies within a standard error below 5%.","PeriodicalId":33282,"journal":{"name":"Journal of Engineering and Sustainable Development","volume":"15 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139129243","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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