safa saib kadhim; Haider Ammash
Abstract
This paper introduced a strengthening technique for flat plates using steel stiffeners. In this paper, the effectiveness of steel stiffeners with different arrangements and numbers on the punching shear strength. The strengthening steel stiffeners were installed around the column and extended to the ...
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This paper introduced a strengthening technique for flat plates using steel stiffeners. In this paper, the effectiveness of steel stiffeners with different arrangements and numbers on the punching shear strength. The strengthening steel stiffeners were installed around the column and extended to the slab and acted as a column capital and designed with the equivalent of a concrete column capital. The study was divided into two lines, the first line was the experimental study involves the molding three reinforced concrete flat slab models strengthening with different dimensions and the molding three reinforced concrete flat slab models strengthening with different dimensions and numbers of steel stiffeners, where the dimensions of steel plates changed as shown for specimen SS1 (100×100mm), SS2 (200×200mm), and SS3 (300×300mm) in addition to reference model without strengthening. The second line that numerical modeling through the ABAQUS finite element program was introduced. Effect of the steel stiffeners' size and the effect of the column's shape (rectangular and circular) that's deal with steel stiffeners were studied experimentally and numerically. A good agreement was obtained between the experimental and theoretical results.
Dhay Waddy Mohammed; Balqeea A. Ahmed; Maysam Th. AL-Hadidi
Abstract
Gypseous soils are common in several regions in the world including Iraq, where more than 28.6% of its surface is covered with this type of soil. This soil, with high gypsum content, causes different problems for construction and strategic projects. As a result of water flow through the soil mass, the ...
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Gypseous soils are common in several regions in the world including Iraq, where more than 28.6% of its surface is covered with this type of soil. This soil, with high gypsum content, causes different problems for construction and strategic projects. As a result of water flow through the soil mass, the permeability and chemical arrangement of these soils varies with time due to the solubility and leaching of gypsum. In this study, the soil of 36% gypsum content, was taken from one location about 100 km southwest of Baghdad, where the samples were taken from depths (0.5 - 1) m below the natural ground and mixed with (3%, 6%, 9%) of Copolymer and Novolac polymer to improve the engineering properties that include: collapsibility, permeability and compaction parameter. Results of experimental work showed noticeable improvement of collapsibility and permeability for the soil treated with polymer materials compared to untreated soil. Adding 3% of polymer (copolymer and novolac polymer) materials gave the best improvement in collapsibility which reached to (44.5 and 46%), respectively, in 3 hours. The improvement in permeability reached to 98.6% copolymer and 86.2% novolac polymer in 1 day.
Muhaned G. Al-Khuzaie; Basim H. Al-Humeidawi; Ra'id F. Al-Sa'idi
Abstract
Solid waste management is one of the big challenges facing most countries around the world. Reusing these wastes in construction project represent one of the most efficient ways to consume these wastes and reduces the demand on natural sources. The Crumb Rubber (CR) of tires is a source of a huge amount ...
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Solid waste management is one of the big challenges facing most countries around the world. Reusing these wastes in construction project represent one of the most efficient ways to consume these wastes and reduces the demand on natural sources. The Crumb Rubber (CR) of tires is a source of a huge amount of solid waste that can be reused in construction projects such as paving of roads. The current research presents an experimental investigation for the dowel bars performance in rubberized concrete pavement. The research involves conducted pullout tests for dowel bars cast in concrete pavement contains a different percentage of CR particle (2%, 4%, and 6% of total aggregate) as partial or total replacement to aggregate on sieves No. 16 and No. 50. Four cases of dowel bars surface were investigated. The results of the study showed that adding CR particles to concrete can significantly reduce the bond between the dowel bars and surrounding concrete pavement which allows for more free movement of dowel bars and reduce joint lockup. The use of treated CR by NaOH solution with standard dowel bars (epoxy coated lubricant steel dowels) can give a superior reduction in pullout load. The reductions were 45%, 66%, and 83% in pullout load for the percentages of 2%, 4%, and 6% crumb rubber respectively compared with the reference mix.
Anteneh Geremew; Yibas Mamuye
Abstract
Know a day’s utilization of local accessible materials is an important stage for sustainable, economic building material on the earth surface. Within them Brick is one of the commonly used construction material around Jimma town due to the availability of clay soil. But brick produced by small ...
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Know a day’s utilization of local accessible materials is an important stage for sustainable, economic building material on the earth surface. Within them Brick is one of the commonly used construction material around Jimma town due to the availability of clay soil. But brick produced by small micros un-skill enterprises rather than by traditional method, its quantity was small and its quality was unsatisfactory, because it can easily break and it has high water absorbing conduct. The purpose of investigation was be to improving the properties of clay soil properties by using Literate soil for in the manufacturing of bricks for masonry units. In order to achieve this researches include, non-probability sampling techniques was be used to collect samples in Jimma area, then collected of samples prepared for different laboratory test and by partially replacing literate soil by 5%, 10%, 15% and 20% on a clay soil in order to get optimum property by different mix ration for different laboratories. Test results indicated that shows that the lightweight bricks could be made from this study without any deterioration in the quality of bricks. Additionally, the compressive strength of the blocks optimum at 15% lateritic soil replace in clay soil contents. The optimum firing temperature furnace at a duration burning of brick was at 1000°C. It’s shown that bricks prepared of clay-laterite earth capable for high resisting capacity rather than for beauty.
Khawla A. Farhan; Muhaned A. Shallal
Abstract
This study presents an experimental investigation for push-out tests in order to evaluate the performance of continuous perfobond connectors. A total of five specimens composed of light-weight concrete-filled steel tubes (square and circle sections) with two reinforced blocks were tested. The measured ...
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This study presents an experimental investigation for push-out tests in order to evaluate the performance of continuous perfobond connectors. A total of five specimens composed of light-weight concrete-filled steel tubes (square and circle sections) with two reinforced blocks were tested. The measured parameters are the compressive strength of the concrete blocks and the type of the section. The specimens were tested under a concentric load applied on the steel tube filled with lightweight concrete; the corresponding slip value was measured using two LVDTs. The experimental results showed that the ultimate shear strength and stiffness of the square steel tube filled with concrete were higher than that of circular samples. The ultimate shear strength and stiffness increased with an increase of concrete compressive strength, while the corresponding slips showed decreasing in their values with increase of the compressive strength of the concrete.
Shahad faiz Hameed; Salih A. Rushdi
Abstract
Activated carbon is a porous material that has a great character to be used for drug delivery system as carrier.It is agreed that drug carriers maintain the concentration of drugs within the required range for a long period of time and undetermined toxicity resulting from the use of overdoses , the ability ...
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Activated carbon is a porous material that has a great character to be used for drug delivery system as carrier.It is agreed that drug carriers maintain the concentration of drugs within the required range for a long period of time and undetermined toxicity resulting from the use of overdoses , the ability to direct the drug to the affected area, immunity, biophysics, and drug efficacy. activated carbon was used in two different particle sizes (0.6µm size with surface area 544.4704 m2/g and 11.042 nm size with surface area 985.6013m2/g ) and Naproxen was used as a drug model. In this research study the effect of the number of parameters, including particle size, weight of drug to carrier weight ratio, on drug loading and temperature, time ,PH solution on mass transfer coefficient in unloading drug. the result of experiments was find that maximum loading efficiency obtain when the particle size of activated carbon was in Nano. size and the ratio of weight drug to AC weight was 1.5. The unloading process was studied by studying the mass transfer coefficient and knowing the effect of the variables on its value ,these variables are time and temperature in addition to the PH value of the solution. The highest value of the mass transfer coefficient was obtained at the beginning of the unloading time ,at temperature 37 co and at solution in PH 6.5 .
Muntadhar H. Ismeala; Bashar J. Hamzaa; Wasan Kadhim Saada
Abstract
At the present time and as a result to the recent developed technology demand for higher data rate and capacity has been increased. For the wireless networks, the combination of radio over fiber (RoF) with (XGPON) Gigabit-capable PON techniques produce a high data rate at lower cost. Thus, this ...
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At the present time and as a result to the recent developed technology demand for higher data rate and capacity has been increased. For the wireless networks, the combination of radio over fiber (RoF) with (XGPON) Gigabit-capable PON techniques produce a high data rate at lower cost. Thus, this paper illustrates that the performance of RoF-XGPON optical link has been analyzed for multi-channel through combining two multiplexing techniques, such as; Subcarrier Multiplexing (SCM) and Wavelength Division Multiplexing (WDM). The proposed system utilizes WDM-xGPON and SCM-XGPON architecture combined with RoF technology with 10 Gpbs data rate and (2.4, 5.8, 10 and 15) GHz radio frequency (RF), when change the optical fiber length between (10 to 80) km. The network performance is compared with various digital quadrate amplitude modulation schemes, like ; 4 - QAM, 16 - QAM and 64 - QAM for various input power (-2, 2, and 6) dB. The performance analysis is based on the optical spectrum of transmitted and received signals for 4-channel, constellation diagram, eye diagram, bit error rate (BER), power received, and quality factor. The result explain that the WDM-XGPON-Rof performs better than SCM-XGPON-Rof for different modulation schemes. The bit error rate for WDM-XGPON less than the SCM-XGPON while the power received recorded to the WDM-XGPON greater than SCM-XGPON and the quality factor for SCM-XGPON less than the WDM-XGPON. Therefore The simulation results show that the WDM-XGPON-RoF gives better performance from SCM-XGPON-RoF. The software optisystem version 15 has been used to simulate this system.
Sajida Kadhem Al-Jasmi; Haitham Al-Thairy
Abstract
This paper presents a numerical simulation of the structural response of reinforced concrete (RC) beams under elevated temperature using the commercial finite element package ABAQUS. A numerical model is firstly suggested by selecting the appropriate geometrical and material properties of the RC beam ...
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This paper presents a numerical simulation of the structural response of reinforced concrete (RC) beams under elevated temperature using the commercial finite element package ABAQUS. A numerical model is firstly suggested by selecting the appropriate geometrical and material properties of the RC beam model at elevated temperature. Thereafter, the suggested numerical model was validated against the experimental tests conducted in this study. The validation results in terms of temperatures- time histories; load-mid span deflection of the RC beams have confirmed the accuracy of the suggested numerical model. The validated numerical model was implemented in conducting a parametric study to investigate the effects of two important parameters on the behavior and failure of RC beams under elevated temperature. These parameters are the effect of the high ranges of elevated temperatures; and the effect of heating rate. The parametric study results have revealed that the failure load and the ductility of RC beams under elevated temperature are not considerably influenced by changing the heating rate. It has also been concluded that the ultimate load capacities of RC beams have considerably decreased by 55.49%, 74.72%, and 81.31% comparing with the control RC beam when they exposed to temperature values of 600 ºC, 700 ºC, and 800ºC respectively. These conclusions may be used in the design of RC beams subjected to fire induced temperature.
Hassan. H. Masallb; Kadhim F. Al-Sultani; Abdul Raheem K. Abid Ali
Abstract
The use of electroless Ni-P plating (EN) coating has attracted a surprising interest in the most recent years. Many useful characteristics of the electroless-plating method have created many benefits in different industries such as oil, gas, electronic, automotive, aerospace, and chemical. Some of the ...
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The use of electroless Ni-P plating (EN) coating has attracted a surprising interest in the most recent years. Many useful characteristics of the electroless-plating method have created many benefits in different industries such as oil, gas, electronic, automotive, aerospace, and chemical. Some of the highlighted properties of such a method are superior corrosion resistance, superior mechanical properties, and uniform thickness of the coating as well as good surface finish properties, good adhesion characteristics, and a wide range of thickness. In this paper, electroless plating has been applied in a (Ni-P) bath at two different times of 2 and 3 hr respectively. After the plating, a heat treatment at 400 °C for an hour under vacuum 10-4 torr has been done. The prepared samples were characterized by energy dispersive spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM). In addition, micro-hardness and corrosion rate following Tafel extrapolation in two acidic solutions (1M HCl and 1M H2SO4) were also determined. Vickers hardness values for specimens, coated by Ni -P at 2 and 3 hr have increased by 47 % and 32 % respectively. X-ray diffraction analysis for the coated surfaces showed two phases of Ni3P and NiP, presented before and after heat treatment. The SEM images of the cross sectional coated specimens revealed that the thickness of the coating is 68.43 and 92.71 µm for 2 and 3 hr coating time, respectively. Tafel analysis showed that the coated specimens had a lower corrosion current density compared to that for the bare specimens. The corrosion current density for the coated specimens in 1M H2SO4 increased by 57 % with 2 hr and 69 % at 3 hr coating time. While, the corrosion current density for the coated specimens in 1M HCl increased by 37 % and 83 % at 2 and 3 hr coating time respectively.
