Nameer Abdul Ameer Alwash; Ghalib Muhsen Habeeb; Fatimah Hameed Naser Al-Mamoori
Abstract
The present study includes an experimental investigation of the behavior of simply supported lightweight aggregate concrete (LWAC) and normal weight concrete (NWC) square slabs reinforced by different ratios of carbon fiber reinforced polymer (CFRP) and/or steel bars reinforcement. The experimental program ...
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The present study includes an experimental investigation of the behavior of simply supported lightweight aggregate concrete (LWAC) and normal weight concrete (NWC) square slabs reinforced by different ratios of carbon fiber reinforced polymer (CFRP) and/or steel bars reinforcement. The experimental program consists of testing nine two-way reinforced concrete square slab models under uniformly distributed load (UDL). They were of the same overall dimensions, (1050×1050×80) mm. The main variables considered in the experimental study are: type of concrete; LWAC or NWC, type of reinforcement; steel, CFRP and hybrid (steel and CFRP) bars with different ratios and arrangements, the behavior of slabs with bottom and top CFRP bars reinforcement and the efficiency of using CFRP bars for strengthening slabs in two directions by using near surface mounted (NSM) technique. In this study, a waste of clay bricks was used as a coarse lightweight aggregate (CLWA) to produce structural lightweight aggregate concrete (SLWAC).It was found that LWAC slab model reinforced by CFRP bars has a lower total weight by amount 20% in comparison with NWC slab model reinforced by CFRP bars with rather a small reduction in slab ultimate load capacity by amount not more than 6.5%. However, it was found that the CFRP reinforced LWAC slab model can achieve ultimate load capacity higher than equivalent steel reinforced LWAC slab model by about 34.62%. NSM technique by CFRP bars in two directions of LWAC slab is very effective and nearly provided the same efficiency of equivalent internal reinforcement.
Rasha Jasim; Mohammed Qasim
Abstract
This research proposed a model describing the relationship between ultrasonic pulse velocity (UPV) and the compressive strength test of concrete containing PET (Polyethylene terephthalate). This was achieved by measuring ultrasonic pulse velocity (UPV) on this type of concrete and comparing the result ...
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This research proposed a model describing the relationship between ultrasonic pulse velocity (UPV) and the compressive strength test of concrete containing PET (Polyethylene terephthalate). This was achieved by measuring ultrasonic pulse velocity (UPV) on this type of concrete and comparing the result of compressive strength tests to clarify the accuracy of the ultrasonic test equation for this type of concrete. Waste bottles of water was used in this study by cutting them into laminar form of fibers with zigzag edges in different length (1,2,3) cm for each volume fraction of PET (1%,2% and 3%) by cement weight with fixed width (0.5) cm. Then, they were incorporated with the concrete. It was noticed from the laboratory tests results that the relationship UPV - strength are related together in the volume fraction of 1% for the length 3cm and the correlation factor (R) is equal to 0.94. This indicates a very good exponential relationship between UPV and compressive strength. Also, the results are compared and discussed with another proposed formula that found in literature.
Israa Amer Dahham
Abstract
An integrated drive arrangement for a wastewater pumping system was designed and modeled to evaluate the energy saving gained from matching motors with Variable Frequency Drive (VFD) and Programmable Logic Controller (PLC). The proposed arrangement utilizes the affinity laws of centrifugal pumps to predict ...
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An integrated drive arrangement for a wastewater pumping system was designed and modeled to evaluate the energy saving gained from matching motors with Variable Frequency Drive (VFD) and Programmable Logic Controller (PLC). The proposed arrangement utilizes the affinity laws of centrifugal pumps to predict the performance of a pump under different rotational speed conditions. The specific energy (Es) is used as a measure of the cost effectiveness of the proposed pumping system.Results have shown that a reduction of 10% in pump speed can save 30% in energy of maximum speed. The energy saving potential is carried out for a real-life case study, and a conclusion to replace on-off controllers currently used for most wastewater pumping systems is necessary. The total energy saving account for more than 50% when integrated drive system was applied for a combined sewer pump station.
Hayder Jawad Mohammed Albattat
Abstract
In latest years the progress and employment of wearable antennas have developed quickly for human monitoring applications. Due to shrink of wireless communication equipment reasons, the microstrip patch antennas with size-reduced are preferred. In this paper, two wearable antennas with different shapes ...
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In latest years the progress and employment of wearable antennas have developed quickly for human monitoring applications. Due to shrink of wireless communication equipment reasons, the microstrip patch antennas with size-reduced are preferred. In this paper, two wearable antennas with different shapes (similar to the button) are introduced. These are compatible for a commercial wireless system platforms such WiFi and WiMax standards. The proposed antennas are very suitable for child indoor monitoring purposes. Here, because of the small size of these antennas (the largest dimension approaches to 25 mm), the assumption of bending the surface, substrate and ground layer are neglected. The operation frequency band for the first antenna is between 5.4 and 5.6 GHz, while its between 3.6 to 3.8 GHz for the second and both with a linearly polarized radiation. For a wearable antenna, a conductive textile was used for the substrate layer, a permittivity of 4.4 is used. A 52% size reduction result of the rose patch size (the 2nd antenna) compared to the size of a regular rectangular patch antenna (the 1st antenna) additionally, investigations had been conducted for different antenna without bending and the antenna’s performance in vicinity to human body. The proficient multiphasic COMSOL software is used for simulation.
Ahmed Naif Ibrahim Al-Khazraji; Rasool Mahdi Awwan Al-Shabbani
Abstract
Aluminum alloy (7075-T6) is widely used in various industries in parts of aircraft, automobiles and other mechanical applications. It is known that the process of the shot peening leads to an increase in the value of residual stresses, which prolong the fatigue life. However, during surface peening of ...
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Aluminum alloy (7075-T6) is widely used in various industries in parts of aircraft, automobiles and other mechanical applications. It is known that the process of the shot peening leads to an increase in the value of residual stresses, which prolong the fatigue life. However, during surface peening of various metals, including aluminum alloy (7075-T6) used in this work, these surfaces become rough where the places to concentrate the stresses, which will fail when exposed to different dynamic stresses. This paper presents an study on the effect of polishing (the roughness surface induced from shot peening process) on endurance limit and residual stresses result by shot peening. In this paper was used three values of surface roughness (1.5, 3, and 5) μm. The obtained results show that the maximum increasing in endurance limit was (53%) at low roughness compared with as received and increasing value roughly to (27%) compared with alloy after shot peening. . The residual stresses gradually increased (-222.735, -229.602, -250.900) Mpa when the roughness surfaces decreased (5, 3, 1.5) μm respectively.
Hamid Athab Al-Jameel; Ali Jihad Kadhim
Abstract
Modeling driver behavior is the corner stone for any traffic simulation model. Driving behavior is a complex task to mimic the reality by simulation model. This study has focused on collecting field data from several rural road sites. These data include lane utilization, lane changing and headway. Then, ...
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Modeling driver behavior is the corner stone for any traffic simulation model. Driving behavior is a complex task to mimic the reality by simulation model. This study has focused on collecting field data from several rural road sites. These data include lane utilization, lane changing and headway. Then, a simulation model has been developed for representing the driver behavior at rural roads. Car-following model developed in this study is safety one. Then, lane changing hybrid model has been developed according to the suggested assumptions by previous studies and collected field data to match the real behavior. Gap acceptance model has been adopted from previous studies which show good consistency with real driver behavior through comparing with other characteristics such as lane changing and lane utilization. The developed model has been calibrated with field data and showed encouraging results.
Ghassan Fadhil SMAISIM
Abstract
This article dealt with an important heat transfer field, which is passive heat transfer technique represented by corrugated tube. The study conducted numerically by ANSYS Fluent 14. The motivation behind the current study was to clarify the characteristics and merits of such tube geometry in terms of ...
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This article dealt with an important heat transfer field, which is passive heat transfer technique represented by corrugated tube. The study conducted numerically by ANSYS Fluent 14. The motivation behind the current study was to clarify the characteristics and merits of such tube geometry in terms of heat transfer and pressure drop. The obtained results reported under constant heat flux, temperature-dependent thermo-physical properties and Reynolds number range of 300-1500. Results show good heat transfer enhancement of 6.15-33.24% in spite of an increase in friction factor of 1.80-2.93 times the smooth values. The corrugated tube with φ =4.76×10-2 has the top thermal 1.16-1.25 for all Reynolds number. The most important finding is that the gained heat transfer is much more than the increase in pressure loss until a certain threshold of Reynolds number about 900, later, the pressure loss increase and dominates over the heat gained. The effect of Prandtl number on the heat transfer for three types of fluids produced too. A criterion correlation equation of Nusselt number developed to describe the cases of four starts spirally corrugated tubes by deviation ±3% compared with the simulation results.
Mohammad F. Abid; Waleed H. Abohameed; Shakir M. Ahmed; Salah M. Ali; Saad Kareem Ibrahim
Abstract
In the present study the applicability of hydrodesulfurization of a mixture of crude oil fractions (e.g., naphtha, kerosene, and gas oil ) in a single hydrotreating reactor packed with NiCoMo/Al2O3 under various operating parameters such as temperature (310-370 oC), pressure (40-55 bars), weight hour ...
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In the present study the applicability of hydrodesulfurization of a mixture of crude oil fractions (e.g., naphtha, kerosene, and gas oil ) in a single hydrotreating reactor packed with NiCoMo/Al2O3 under various operating parameters such as temperature (310-370 oC), pressure (40-55 bars), weight hour space velocity (1.2 to 3.6 h-1), and hydrogen-to- liquid hydrocarbon ratio (150-300 vol/vol). Experimental results showed that temperature and pressure have a positive effect on process performance while weight hour space velocity gives a different trend. The optimum value of (H2/Hydrocarbon) ratio was found experimentally to be 200 vol/vol after which the increase in this ratio cause reduction in HDS% because decrease in contact between H2 gas and Hydrocarbon in reactor. Results showed that the best conditions (350 oC, 50 bars, 1.2 h-1, and 200 vol/vol) in which gave the hydrotreating (HDS) efficiency of 95.8%.The results confirmed the applicability of the NiCoMo/Al2O3 catalyst for HDS reaction of a mixture of middle distillate (e.g., naphtha, kerosene, and gas oil). It was found that at higher pressure and temperature (i.e., T> 350 oC; P> 50 bars) a thermodynamic equilibrium was established. As observed, there is a 1.6% reduction in gas oil less than that of the conventional method. However, kerosene, heavy naphtha, and light naphtha undergo increases of 0.6%, 0.75%, and 2.75% respectively over these from conventional method. These results reveal that the quantity of fractions is almost the same for both methods. As it can be observed, that measured properties of the oil fractions produced by the proposed method are almost the same as those produced by conventional method. However, specific gravity (sp.gr) of the oil cuts produced by present study (i.e. sp.gr of kerosene, heavy naphtha, and light naphtha 0.785, 0.728, 0.655 respectively) is somewhat less than sp.gr of the same fractions produced by conventional methods (i.e. sp.gr of kerosene, heavy naphtha, and light naphtha 0.788, 0.738, 0.65 respectively), which gives a clear indication of properties improvement of these fractions. Experimental results confirmed the applicability of the proposed method for HDS of a mixture of Iraqi middle distillates (i.e., naphtha, kerosene, and gas oil) simultaneously in a single fixed bed reactor.
Heider Yasser Thamir Alyasiri
Abstract
The samples of AISI 1018 Low carbon steel were heated to austenite zone then cooled in different mediums with different cooling rates. Mechanical tests show increase in hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio as cooling rate is increase. Ductility has ...
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The samples of AISI 1018 Low carbon steel were heated to austenite zone then cooled in different mediums with different cooling rates. Mechanical tests show increase in hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio as cooling rate is increase. Ductility has inverse proportionality to cooling rate. The resulting microstructures show decreasing in grains sizes accompanying to cooling rate increase. The relations between mechanical properties and grains size are opposites of relations between mechanical properties with cooling rates. Hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio increase as grains size decreases, while ductility decreases.
Volume 10, Issue 4 , December 2017, Pages 496-504
Abstract
Construction and demolition of buildings and structures are producing excess or waste material which is including concrete, brick, steel, etc. Conservation and reuse of resources is a necessity in achieving sustainability across the globe, crushed brick could be safely added to crush rock blends in pavement ...
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Construction and demolition of buildings and structures are producing excess or waste material which is including concrete, brick, steel, etc. Conservation and reuse of resources is a necessity in achieving sustainability across the globe, crushed brick could be safely added to crush rock blends in pavement sub-base applications with percent up to 25%. The experimental work was consisted of two groups of samples depending on percent volume of each material, each group samples have 6 different layering blends patterns prepared by spreading the pure materials in layers (segregated form) of Crushed Bricks Sand (CBS) and Natural Aggregate (NA), in addition to the two control samples and then experimentally tested to compare with the requirements of Iraqi specification for roads and bridges. The experimental work was consisted of Atterberg limits, sieve analysis, moisture-density relationship and California Bearing Ratio (CBR) tests. The results show that using of the crushed bricks as sand with natural aggregate as unbound subbase in segregated form is feasible and agreed with the Iraqi specification requirements because the CBR of CBS was improved when blended with the NA at all the patterns, the best pattern is that which containing three layers NA and two CBS (60% NA and 40% CBS by volume) and the NA was at the top, then CBS in alternated sequence that improves the CBR value to 1.6 times compared with NA control or 8 times of CBS control because the sporadic distribution reduces the effect of the low bearing material, in another words; collect the layers of the same material doesn't give best improvement.
