Qutaiba Najm Abdullah Alobaidy, A. I. Abdulla, M. Al-Mashaykhi
The purpose of this study is to investigate the shear behavior of hollow ferrocement beams of self-compacting mortar reinforced with various types of metallic (steel wire mesh) and non-metallic (fiber glass mesh) reinforcement. The experimental program consists of casting eight ferrocement beams with dimensions of 150×225×2000 mm, with 50 mm of ferrocement thickness and a polystyrene cork core of 50×125 mm. The study parameters were the type of shear reinforcement and the number of layers of wire mesh. The results showed that the ultimate load of the beams reinforced with several layers of the fiber glass mesh (1, 2, and 3) was decreased by (3.27%, 16.52%, and 9.38%) respectively, compared to the beams reinforced with layers of steel wire mesh (1, 2 and 3). The ultimate load of these beams increased by (33.71%, 73.28%, and 122.11%) respectively, compared to the beams without shear reinforcement. Also, the ultimate load of the beams reinforced with layers of welded wire mesh was increased by (38.23%, 107.56%, and 145.09%) respectively, compared to the beams without shear reinforcement. The ductility and toughness of the beams reinforced with several layers of the fiber glass mesh (1, 2, and three) were decreased by (1.68%, 2.11%, 2.68%) and (29.39%, 25.91%, 16.06%) respectively, compared to beams reinforced with several layers of steel wire mesh (1, 2 and 3). The crack propagation was reduced and its number and crack width decreased by using steel wire mesh and fiber glass wire mesh instead of stirrups, especially in beams with two and three layers of wire mesh. The results also showed that the use of glass fiber or welded wire mesh in the reinforcement of hollow beams instead of steel stirrups has a significant effect on the failure load, deflections, crack patterns, and shear stresses, despite the clear preference for beams reinforced with steel wire mesh.
{"title":"Shear Behavior of Hollow Ferrocement Beam Reinforced by Steel and Fiberglass Meshes","authors":"Qutaiba Najm Abdullah Alobaidy, A. I. Abdulla, M. Al-Mashaykhi","doi":"10.25130/tjes.29.4.4","DOIUrl":"https://doi.org/10.25130/tjes.29.4.4","url":null,"abstract":"The purpose of this study is to investigate the shear behavior of hollow ferrocement beams of self-compacting mortar reinforced with various types of metallic (steel wire mesh) and non-metallic (fiber glass mesh) reinforcement. The experimental program consists of casting eight ferrocement beams with dimensions of 150×225×2000 mm, with 50 mm of ferrocement thickness and a polystyrene cork core of 50×125 mm. The study parameters were the type of shear reinforcement and the number of layers of wire mesh. The results showed that the ultimate load of the beams reinforced with several layers of the fiber glass mesh (1, 2, and 3) was decreased by (3.27%, 16.52%, and 9.38%) respectively, compared to the beams reinforced with layers of steel wire mesh (1, 2 and 3). The ultimate load of these beams increased by (33.71%, 73.28%, and 122.11%) respectively, compared to the beams without shear reinforcement. Also, the ultimate load of the beams reinforced with layers of welded wire mesh was increased by (38.23%, 107.56%, and 145.09%) respectively, compared to the beams without shear reinforcement. The ductility and toughness of the beams reinforced with several layers of the fiber glass mesh (1, 2, and three) were decreased by (1.68%, 2.11%, 2.68%) and (29.39%, 25.91%, 16.06%) respectively, compared to beams reinforced with several layers of steel wire mesh (1, 2 and 3). The crack propagation was reduced and its number and crack width decreased by using steel wire mesh and fiber glass wire mesh instead of stirrups, especially in beams with two and three layers of wire mesh. The results also showed that the use of glass fiber or welded wire mesh in the reinforcement of hollow beams instead of steel stirrups has a significant effect on the failure load, deflections, crack patterns, and shear stresses, despite the clear preference for beams reinforced with steel wire mesh.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44228753","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}
There are vertical slopes on the western banks of Tigris near Al-Alam Bridge in Tikrit, Iraq. These slopes are not supported and are located near an important road at Tikrit University. This study aims to find a safety factor (FOS) of the slope to prevent failure, besides its effect on human and financial losses. The study consists of two parts: the first part studied the layers of the slope and found the soil resistance coefficients. The second part analyzed the stability of the natural slope itself under the impact of the water level change of the Tigris River and the external loading. The analysis was done by a program called (PLAXIS 3D), which depends on the finite element method. The finite element method is a numerical approach that searches for approximate solutions and solves problems by dividing the problem into several triangular elements linked to each other by points called (nodes). The results showed that the vertical slope stability at the natural state with no influences indicated was in a semi-stable state with a factor of safety equal to (1.04865). The factor of safety decreased by (0.423%) with rising the river level until it reached (1.04074) at (93 m a.s.l.[1]). As for the applied external loads condition, the factor of safety for imposed (50,150 and 250 kN/m2) decreased by (4.738%), then the soil body failed when the factor of safety was (0.9902). In the critical state, the soil body failure at this stage and the factor of safety became equal to (0.98769) with decreasing by (5.812%).
伊拉克提克里特Al-Alam大桥附近的底格里斯河西岸有垂直的斜坡。这些斜坡没有支撑，位于提克里特大学的一条重要道路附近。本研究的目的是找出边坡的安全系数(FOS)，以防止破坏，除了对人员和经济损失的影响。研究分为两部分:第一部分对边坡的各层进行了研究，求得了土体阻力系数。第二部分分析了底格里斯河水位变化和外部荷载作用下天然边坡本身的稳定性。该分析是由一个名为PLAXIS 3D的程序完成的，该程序依赖于有限元法。有限元法是一种数值方法，它通过将问题划分为几个三角形单元，通过称为节点的点相互连接来搜索近似解并解决问题。结果表明:在未受影响的自然状态下，竖向边坡稳定性处于半稳定状态，安全系数为(1.04865)。随着水位的升高，安全系数降低0.423%，在(93 m a.s.l.[1])处达到1.04074。在外加荷载条件下，施加(50,150和250 kN/m2)的安全系数减小了(4.738%)，当安全系数为(0.9902)时土体破坏。在临界状态下，该阶段土体破坏和安全系数为0.98769，减小了5.812%。
{"title":"Slope Stability Analysis of Vertical Unsupported Slopes near West Approaches of Al-Alam Bridge","authors":"Fatima A. K. Khattab, Farouk M. Muhauwiss","doi":"10.25130/tjes.29.4.3","DOIUrl":"https://doi.org/10.25130/tjes.29.4.3","url":null,"abstract":"There are vertical slopes on the western banks of Tigris near Al-Alam Bridge in Tikrit, Iraq. These slopes are not supported and are located near an important road at Tikrit University. This study aims to find a safety factor (FOS) of the slope to prevent failure, besides its effect on human and financial losses. The study consists of two parts: the first part studied the layers of the slope and found the soil resistance coefficients. The second part analyzed the stability of the natural slope itself under the impact of the water level change of the Tigris River and the external loading. The analysis was done by a program called (PLAXIS 3D), which depends on the finite element method. The finite element method is a numerical approach that searches for approximate solutions and solves problems by dividing the problem into several triangular elements linked to each other by points called (nodes). The results showed that the vertical slope stability at the natural state with no influences indicated was in a semi-stable state with a factor of safety equal to (1.04865). The factor of safety decreased by (0.423%) with rising the river level until it reached (1.04074) at (93 m a.s.l.[1]). As for the applied external loads condition, the factor of safety for imposed (50,150 and 250 kN/m2) decreased by (4.738%), then the soil body failed when the factor of safety was (0.9902). In the critical state, the soil body failure at this stage and the factor of safety became equal to (0.98769) with decreasing by (5.812%).","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41490903","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}
Layla M. Salih, T. M. Al-Qaradaghi, J. J. H. Ameen
Channel coding technique is a fundamental building block in any modern communication system to realize reliable, fast, and secure data transmission. At the same time, it is a challenging and crucial task, as the data transmission happens in a channel where noise, fading, and other impairments are present. The Low-Density Parity-Check (LDPC) codes give substantial results close to the Shannon limit when the complexity and processing delay time are unlimited. In this paper, the performance of the LDPC decoding with four algorithms was investigated. The investigated four algorithms were Belief Propagation (BP), Layered Belief Propagation (LBP), Normalized min-sum (NMS), and Offset min-sum (OMS). These algorithms were examined for code rates ranging from 1/3 to 9/10 and message block lengths (64, 512, 1024, and 5120) bits. The simulation results revealed the flexibility of these decoders in supporting these code rates and block lengths, which enables their usage in a wide range of applications and scenarios for fifth-generation (5G) wireless communication. In addition, the effect of the maximum number of decoding iterations on the error correction performance was investigated, and a gain of 5.6 dB can be obtained by using 32 decoding iterations at BER=2*10-3 instead of one decoding iteration. The results showed that the decoders performed better for longer message blocks than for short message blocks, and less power was required for transmitting longer messages. Finally, the comparison results of their performance in terms of bit error rate (BER) under the same conditions showed a gain of 0.8 dB using LBP at BER= 10-5 compared with the NMS decoding algorithm.
{"title":"Performance Analysis of Different Flexible Decoding Algorithms for NR-LDPC Codes","authors":"Layla M. Salih, T. M. Al-Qaradaghi, J. J. H. Ameen","doi":"10.25130/tjes.29.4.2","DOIUrl":"https://doi.org/10.25130/tjes.29.4.2","url":null,"abstract":"Channel coding technique is a fundamental building block in any modern communication system to realize reliable, fast, and secure data transmission. At the same time, it is a challenging and crucial task, as the data transmission happens in a channel where noise, fading, and other impairments are present. The Low-Density Parity-Check (LDPC) codes give substantial results close to the Shannon limit when the complexity and processing delay time are unlimited. In this paper, the performance of the LDPC decoding with four algorithms was investigated. The investigated four algorithms were Belief Propagation (BP), Layered Belief Propagation (LBP), Normalized min-sum (NMS), and Offset min-sum (OMS). These algorithms were examined for code rates ranging from 1/3 to 9/10 and message block lengths (64, 512, 1024, and 5120) bits. The simulation results revealed the flexibility of these decoders in supporting these code rates and block lengths, which enables their usage in a wide range of applications and scenarios for fifth-generation (5G) wireless communication. In addition, the effect of the maximum number of decoding iterations on the error correction performance was investigated, and a gain of 5.6 dB can be obtained by using 32 decoding iterations at BER=2*10-3 instead of one decoding iteration. The results showed that the decoders performed better for longer message blocks than for short message blocks, and less power was required for transmitting longer messages. Finally, the comparison results of their performance in terms of bit error rate (BER) under the same conditions showed a gain of 0.8 dB using LBP at BER= 10-5 compared with the NMS decoding algorithm.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43315267","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}
Khalaf S. Gaeid, Waleed M. Zapar, Rami A. Maher, A. L. Salih, Mohib A. Qasim
This paper presents the steps of designing, controlling, and implementing a 3kW Gallium-Nitride (GaN)-based bridgeless totem-pole power factor corrector (PFC) for single-phase 230V rectifier applications. The bridgeless design of such a converter combined with zero-recovery switching loss of GaN transistors enables more efficient design operation compared to traditional Si-based solutions. Thermally efficient design with forced-air cooling for the switching devices increased the power density beyond 100W/inch3 while keeping the power switches temperatures less than the thermal limits. Continuous Conduction Mode (CCM) was adopted in this work for better converter stability and was analyzed thoroughly along with the losses breakdown for each part of the converter. The digital control model of the converter was discussed in detail accompanied by the hardware design steps for the converter. Experimental results proved a maximum efficiency of 98.9% during 2.4kW operation and 98.6% during 3kW (full load) operation with minimum Total Harmonics Distortion (THD) of AC input current of 2.78% at rated current (13A) when converting the AC input voltage (230V) to 400 VDC.
{"title":"Digitally Controlled Bridgeless Totem-Pole Power Factor Corrector","authors":"Khalaf S. Gaeid, Waleed M. Zapar, Rami A. Maher, A. L. Salih, Mohib A. Qasim","doi":"10.25130/tjes.29.3.10","DOIUrl":"https://doi.org/10.25130/tjes.29.3.10","url":null,"abstract":"This paper presents the steps of designing, controlling, and implementing a 3kW Gallium-Nitride (GaN)-based bridgeless totem-pole power factor corrector (PFC) for single-phase 230V rectifier applications. The bridgeless design of such a converter combined with zero-recovery switching loss of GaN transistors enables more efficient design operation compared to traditional Si-based solutions. Thermally efficient design with forced-air cooling for the switching devices increased the power density beyond 100W/inch3 while keeping the power switches temperatures less than the thermal limits. Continuous Conduction Mode (CCM) was adopted in this work for better converter stability and was analyzed thoroughly along with the losses breakdown for each part of the converter. The digital control model of the converter was discussed in detail accompanied by the hardware design steps for the converter. Experimental results proved a maximum efficiency of 98.9% during 2.4kW operation and 98.6% during 3kW (full load) operation with minimum Total Harmonics Distortion (THD) of AC input current of 2.78% at rated current (13A) when converting the AC input voltage (230V) to 400 VDC.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43888650","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}
Civil structures were designed to carry a variety of loading during their service life, including fire hazards. As a result, providing fire safety to structural members is one of the most important tasks in civil infrastructure design. Steel structural members are subject to fire-induced damage or collapse due to their high heat conductivity and quick loss of strength and stiffness qualities. Furthermore, the failure in steel beams under the combined effects of bending, shear, and fire loading is poorly understood in the literature. A present study consists of experimental investigations on the fire response of steel beams under bending and shear dominant loading. The specimens have a constant length of 1250 mm. The total depth of the specimens was changed according to the section chosen: 4 in, 6 in, and 8 in (10 cm, 15 cm, and 20 cm). The results of tests show that beams can fail suddenly due to a high drop in yield and ultimate strength of the steel beam. the increase in temperature degree reduced greatly the yield and ultimate flexural strength of the steel beams with different sizes (for all groups). This reduction reached at some times to 50% for the ultimate strength capacity of the specimen. Shear strength is also affected greatly by fire exposure and the reduction reached to about 38%. Furthermore, the design strength capacity can only tolerate loads at low temperatures. This reduction in strength was noted under flexural and shear dominant loading. Moreover, the design strength capacity can withstand against loading at low-temperature degrees only.
{"title":"Behavior of Steel Beams Subjected to Bending and Shear Loading Under Localized Fire Conditions","authors":"Omer Farooq Ibraheem, Hafssa Ali Abdullah","doi":"10.25130/tjes.29.3.9","DOIUrl":"https://doi.org/10.25130/tjes.29.3.9","url":null,"abstract":"Civil structures were designed to carry a variety of loading during their service life, including fire hazards. As a result, providing fire safety to structural members is one of the most important tasks in civil infrastructure design. Steel structural members are subject to fire-induced damage or collapse due to their high heat conductivity and quick loss of strength and stiffness qualities. Furthermore, the failure in steel beams under the combined effects of bending, shear, and fire loading is poorly understood in the literature. A present study consists of experimental investigations on the fire response of steel beams under bending and shear dominant loading. The specimens have a constant length of 1250 mm. The total depth of the specimens was changed according to the section chosen: 4 in, 6 in, and 8 in (10 cm, 15 cm, and 20 cm). The results of tests show that beams can fail suddenly due to a high drop in yield and ultimate strength of the steel beam. the increase in temperature degree reduced greatly the yield and ultimate flexural strength of the steel beams with different sizes (for all groups). This reduction reached at some times to 50% for the ultimate strength capacity of the specimen. Shear strength is also affected greatly by fire exposure and the reduction reached to about 38%. Furthermore, the design strength capacity can only tolerate loads at low temperatures. This reduction in strength was noted under flexural and shear dominant loading. Moreover, the design strength capacity can withstand against loading at low-temperature degrees only.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47623388","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 the recent period, developed countries have resorted to using smart grids more widely as a solution to the problems of shortage of electric power, because it is the most environmentally friendly due to its reliance on renewable energy sources and does not require expensive maintenance due to the proximity of its stations to the feeding areas. However, these networks faced problems in sharing the required power between the inverters of the user stations, as well as regulating their frequency when connected to the main network to fill the shortage of electrical energy. This paper aims to achieve the actual sharing of power (Active and Reactive) supply to the varying load between the smart grid inverters by designing a PID (Proportional, Integral, Derivative) controller. PID controller gain tuning by PSO (particle swarm optimization) algorithm which is based on PWM (Pulse Width Modulation) scaler that feeds the Microgrid inverter switches. Frequency control can be achieved when connecting Microgrid with the main grid by using PLL (Phase Locked Loop) to generate a controlled reference signal for the PID controller.
{"title":"Power Sharing and Frequency Control in Inverter-based Microgrids","authors":"Sazgar Abdualaziz Wali, Aree Akram Muhammed","doi":"10.25130/tjes.29.3.8","DOIUrl":"https://doi.org/10.25130/tjes.29.3.8","url":null,"abstract":"In the recent period, developed countries have resorted to using smart grids more widely as a solution to the problems of shortage of electric power, because it is the most environmentally friendly due to its reliance on renewable energy sources and does not require expensive maintenance due to the proximity of its stations to the feeding areas. However, these networks faced problems in sharing the required power between the inverters of the user stations, as well as regulating their frequency when connected to the main network to fill the shortage of electrical energy. This paper aims to achieve the actual sharing of power (Active and Reactive) supply to the varying load between the smart grid inverters by designing a PID (Proportional, Integral, Derivative) controller. PID controller gain tuning by PSO (particle swarm optimization) algorithm which is based on PWM (Pulse Width Modulation) scaler that feeds the Microgrid inverter switches. Frequency control can be achieved when connecting Microgrid with the main grid by using PLL (Phase Locked Loop) to generate a controlled reference signal for the PID controller.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47150585","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 the design of earth dams, it must be considered that the water leakage through the earth dam generates upward and pore pressure, in addition to leakage forces that cause internal erosion, which has a direct influence on the structural stability of this system. Also, the rising and dropping in the water level has a direct effect on the stability of the dam's face slope. One way to solve these issues is the installation of a core or a horizontal water drainage system. The present study relied on the GEO-Studio computer tool to evaluate cross-sectional models of earthen dams by determining the safety factor under different situations represented by a change in filter type, and the flow state as a result of raising and lowering the water level at the dam reservoir and the full fill condition of the dam reservoir. The research found that the existence of a core substantially contributed to improving the safety coefficient for the case of rising the water level (2m) and rapidly rising by assigning it the greatest safety coefficient values. The absence of a filter had an opposite influence on the safety coefficient by decreasing it. Also, the factor of safety for the downstream slope was affected by less than 5% for different flow conditions, compared with the higher effect generated by the upstream slope. Furthermore, an artificial neural network model with an accuracy ratio of more than 97% was developed for the predicted safety factor.
{"title":"Theoretical Analysis and Development of an Artificial Neural Network Model to Evaluate Earthen Dam Slope Stability","authors":"R. Hussain, Asmaa Al-samarrae","doi":"10.25130/tjes.29.4.1","DOIUrl":"https://doi.org/10.25130/tjes.29.4.1","url":null,"abstract":"In the design of earth dams, it must be considered that the water leakage through the earth dam generates upward and pore pressure, in addition to leakage forces that cause internal erosion, which has a direct influence on the structural stability of this system. Also, the rising and dropping in the water level has a direct effect on the stability of the dam's face slope. One way to solve these issues is the installation of a core or a horizontal water drainage system. The present study relied on the GEO-Studio computer tool to evaluate cross-sectional models of earthen dams by determining the safety factor under different situations represented by a change in filter type, and the flow state as a result of raising and lowering the water level at the dam reservoir and the full fill condition of the dam reservoir. The research found that the existence of a core substantially contributed to improving the safety coefficient for the case of rising the water level (2m) and rapidly rising by assigning it the greatest safety coefficient values. The absence of a filter had an opposite influence on the safety coefficient by decreasing it. Also, the factor of safety for the downstream slope was affected by less than 5% for different flow conditions, compared with the higher effect generated by the upstream slope. Furthermore, an artificial neural network model with an accuracy ratio of more than 97% was developed for the predicted safety factor.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48975280","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}
Gypseous soils are considered problematic soils because the soil cavities happen during receiving the water or this type of soil and solving gypsum materials and contract in a soil volume. In this study, three types of gypseous soils are used; soil1, soil2, and soil3 with gypsum content (28.71%, 43.6%, and 54.88%) respectively, petroleum products (engine oil, fuel oil, and kerosene) are added to the soils with percentages (3%, 6%, 9%, and 12%) for each product. The result showed that specific gravity, liquid limit, optimum moisture content (O.M.C), and maximum dry density decreased with an increased percentage of product for all types of products. The direct shear (dry and soaked case) results show that increasing the (angle of internal friction and the soil cohesion) for soil1, soil2, and soil3 by adding engine oil and fuel oil. Still, when the soils were treated with kerosene, the angle of internal friction increased while cohesion decreased. The collapse potential for the treated soils increases with increasing gypsum content for all petroleum products. The collapse potential (CP) for (soil1) decreased by 47% when using 6% of the engine oil, 48.8% when using 9% of the fuel oil, and 55% when using 9% of the kerosene. The same percentage of the petroleum products (engine oil, fuel oil, and kerosene) decrease the collapse potential for (soil2), (47%, 46%, and 50%) respectively and decrease the collapse potential for (soil 3), (51%, 47.7%, and 52%) respectively. In the unconfined compressive test applied on (soil1) using maximum density, the results show that the soil strength increased (26% and 10%) when using 6% and engine oil and fuel oil, respectively, while the soil strength decreased by 29% when treated with 9% of kerosene.
{"title":"A Comparative Study for the Effect of Some Petroleum Products on the Engineering Properties of Gypseous Soils","authors":"Asal Mahmud Hamad, M. Jassam","doi":"10.25130/tjes.29.3.7","DOIUrl":"https://doi.org/10.25130/tjes.29.3.7","url":null,"abstract":"Gypseous soils are considered problematic soils because the soil cavities happen during receiving the water or this type of soil and solving gypsum materials and contract in a soil volume. In this study, three types of gypseous soils are used; soil1, soil2, and soil3 with gypsum content (28.71%, 43.6%, and 54.88%) respectively, petroleum products (engine oil, fuel oil, and kerosene) are added to the soils with percentages (3%, 6%, 9%, and 12%) for each product. The result showed that specific gravity, liquid limit, optimum moisture content (O.M.C), and maximum dry density decreased with an increased percentage of product for all types of products. The direct shear (dry and soaked case) results show that increasing the (angle of internal friction and the soil cohesion) for soil1, soil2, and soil3 by adding engine oil and fuel oil. Still, when the soils were treated with kerosene, the angle of internal friction increased while cohesion decreased. The collapse potential for the treated soils increases with increasing gypsum content for all petroleum products. The collapse potential (CP) for (soil1) decreased by 47% when using 6% of the engine oil, 48.8% when using 9% of the fuel oil, and 55% when using 9% of the kerosene. The same percentage of the petroleum products (engine oil, fuel oil, and kerosene) decrease the collapse potential for (soil2), (47%, 46%, and 50%) respectively and decrease the collapse potential for (soil 3), (51%, 47.7%, and 52%) respectively. In the unconfined compressive test applied on (soil1) using maximum density, the results show that the soil strength increased (26% and 10%) when using 6% and engine oil and fuel oil, respectively, while the soil strength decreased by 29% when treated with 9% of kerosene.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48411614","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 research, two subjects are presented. The first one was, studying the effect of the ellipticity ratio on the bearing performance characteristics (flow rate, load number, power absorbed, and stiffness coefficients), where three different values of the ellipticity ratio (0.5, 1, and 1.5) were studied and the conventional bearing was considered as a reference for comparison with the elliptical bearing of different values of ellipticity ratio to demonstrate the effect of ellipticity ratio on the bearing performance, while the other aspect was, studying the effect of aspect ratio on the elliptical bearing performance. Three different values of aspect ratio (0.5, 1, and 1.5) were studied. This was achieved within the range (0.1 - 0.8) for the eccentricity ratio. The finite difference method was used to solve Reynold’s equation numerically to obtain the pressure distribution on the bearing surface and then the bearing characteristics were computed. The computer program (Matlab R2015a) was used for solving the equations used in this study. From the results, it was observed that increasing the ellipticity ratio gives an increase in the flow rate values and a decrease in the (load number, power losses, Krr, Kss, |Krs| and Ksr) values, while, increasing the aspect ratio gives an increase in the (flow rate, power losses, Krr, Kss, |Krs| and Ksr) values and a decrease in the load number values. It was also observed that the elliptical bearing has a (higher flow rate, lower load capacity, and less power losses), than the conventional bearing. In addition, the elliptical bearing has higher principle stiffness coefficients (Krr and Kss) in the region (n<0.41) and (n<0.66), respectively, and lower cross-coupling stiffness coefficients (Krs and Ksr), than the conventional bearing.
{"title":"Theoretical Comparison of Characteristics between Elliptical and Conventional Hydrodynamic Journal Bearing","authors":"I. Muhsin, D. Abdurrahman","doi":"10.25130/tjes.29.3.6","DOIUrl":"https://doi.org/10.25130/tjes.29.3.6","url":null,"abstract":"In this research, two subjects are presented. The first one was, studying the effect of the ellipticity ratio on the bearing performance characteristics (flow rate, load number, power absorbed, and stiffness coefficients), where three different values of the ellipticity ratio (0.5, 1, and 1.5) were studied and the conventional bearing was considered as a reference for comparison with the elliptical bearing of different values of ellipticity ratio to demonstrate the effect of ellipticity ratio on the bearing performance, while the other aspect was, studying the effect of aspect ratio on the elliptical bearing performance. Three different values of aspect ratio (0.5, 1, and 1.5) were studied. This was achieved within the range (0.1 - 0.8) for the eccentricity ratio. The finite difference method was used to solve Reynold’s equation numerically to obtain the pressure distribution on the bearing surface and then the bearing characteristics were computed. The computer program (Matlab R2015a) was used for solving the equations used in this study. From the results, it was observed that increasing the ellipticity ratio gives an increase in the flow rate values and a decrease in the (load number, power losses, Krr, Kss, |Krs| and Ksr) values, while, increasing the aspect ratio gives an increase in the (flow rate, power losses, Krr, Kss, |Krs| and Ksr) values and a decrease in the load number values. It was also observed that the elliptical bearing has a (higher flow rate, lower load capacity, and less power losses), than the conventional bearing. In addition, the elliptical bearing has higher principle stiffness coefficients (Krr and Kss) in the region (n<0.41) and (n<0.66), respectively, and lower cross-coupling stiffness coefficients (Krs and Ksr), than the conventional bearing.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48660169","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}
Many investments and commitments have recently been set to use renewable energy source, overcome energy crisis and align with climate target. Solar power development and deployment make investment in power generation sustainability. The goal of this study is harvesting energy by rotating solar panel toward the sun direction. Astronomical formula is derivate to calculate the sun altitude and azimuth depending on given latitude, longitude coordination. The photovoltaic (PV) panels rotate horizontally and track the sun direction in 9 positions regarding to their actual time and calculated azimuth angle. Partial shaded effectiveness that produces between the adjacent panels due to PV panel’s inclination is calculate accordingly. The total increment of power production from fix to tracked panel structure is 17.3% per day. The extra power generation is distributed over the period between solar noon times.
{"title":"Modeling Horizontal Single Axis Solar Tracker Upon Sun-Earth Geometric Relationships","authors":"Gzing Adil Mohammed, Zana Saleem Mohammed","doi":"10.25130/tjes.29.3.5","DOIUrl":"https://doi.org/10.25130/tjes.29.3.5","url":null,"abstract":"Many investments and commitments have recently been set to use renewable energy source, overcome energy crisis and align with climate target. Solar power development and deployment make investment in power generation sustainability. The goal of this study is harvesting energy by rotating solar panel toward the sun direction. Astronomical formula is derivate to calculate the sun altitude and azimuth depending on given latitude, longitude coordination. The photovoltaic (PV) panels rotate horizontally and track the sun direction in 9 positions regarding to their actual time and calculated azimuth angle. Partial shaded effectiveness that produces between the adjacent panels due to PV panel’s inclination is calculate accordingly. The total increment of power production from fix to tracked panel structure is 17.3% per day. The extra power generation is distributed over the period between solar noon times.","PeriodicalId":30589,"journal":{"name":"Tikrit Journal of Engineering Sciences","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47164051","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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