zahraa hadi marzoq; Tumadhir Merawi Borhan
Abstract
Reactive Powder Concrete (RPC) is one of the new and most important concrete manufacturing advancements. A significant number of researchers have studied the mechanical properties of such type of concrete and the effect of different parameters on it. Some of these researchers presented questions to predict ...
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Reactive Powder Concrete (RPC) is one of the new and most important concrete manufacturing advancements. A significant number of researchers have studied the mechanical properties of such type of concrete and the effect of different parameters on it. Some of these researchers presented questions to predict the properties of reactive powder concrete depends on its components and the method of curing. This research presents an experimental investigation on the mechanical properties of RPC such as compressive strength, splitting tensile strength and flexural strength. The findings were compared to the previous studies’ experimental work and formulated equations.
Dhuha Rasheed Saber; Mushtaq Ismael Hasan
Abstract
An experimental investigation is conducted to study the potential of enhancement cooling performance for mini channel heat sink by using different cooling mediums which are air, pure paraffin wax, and nano-enhanced phase change material (NEPCM). Paraffin wax used as phase change material (PCM) ...
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An experimental investigation is conducted to study the potential of enhancement cooling performance for mini channel heat sink by using different cooling mediums which are air, pure paraffin wax, and nano-enhanced phase change material (NEPCM). Paraffin wax used as phase change material (PCM) and mixed with three types of nanoparticles of alumina (Al2O3 ) and titanium dioxide (TiO2) to improve the thermal conductivity of PCM. Volume fraction values for each type of nanoparticles are (0.1, 0.2, 0.3, 0.4, and 0.5)% which dispersed through PCM. A constant heat flux had been applied to the heat sink base with values (449, 963, 1839, and 4946)W/m2. The results showed enhancement in cooling performance when dispersion the nanoparticles through the PCM which mean reducing the temperature of heat sink base as compared with air and pure paraffin wax. The experimental results also indicated that the cooling performance enhancement of NEPCM and reduction the time of melting process continue with increasing the concentrations of nanoparticles for all material types but any surplus addition may cause negative effect due to sedimentation. Optimum cooling performance of mini heat sink is achieved with Al2O3 –PCM then TiO2-PCM as compared with air with percentage of temperature reduction of 23.306 and 22.069% respectively as compared to air.
Zaharaa Nazzal; Ali A. Jazie
Abstract
Increasing demand for fossil fuels and the resulting emissions for it have become an interesting research topic for biofuel production from renewable natural resources aimed at development and reduce greenhouse gas emissions. In this research, algae was used as a biological source for the production ...
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Increasing demand for fossil fuels and the resulting emissions for it have become an interesting research topic for biofuel production from renewable natural resources aimed at development and reduce greenhouse gas emissions. In this research, algae was used as a biological source for the production of biofuels because it has many advantages, represented by its high oil content, which may reach 50% of the dry cell weight, it does not need arable land, it can grow even in salt water. A Cladophora glomerata alga was used and extraction oil from biomass with the help of methanol solvent was using a Soxhlet device. The produced oil was being tested by Fourier Transform-Infrared Spectroscopy (FTIR) as well as by thermal analysis and gas chromatography - mass spectrometry (GC-MS). After that the resulting oil was used through the process of deoxygenation using a high pressure reactor with a heterogeneous catalyst prepared from natural sources. Recent studies have shown that these catalysts have high performance compared to other catalysts as well as low cost, because they can be obtained from natural sources that are abundantly available. Heterogeneous catalysts were produced in this paper from chicken eggshells by calcining them at high temperatures to obtain calcium oxide (CaO) and these catalysts were characterized using X-Ray Diffraction (XRD), Fourier Analysis of Infrared Spectrum (FTIR) and Brunauer Emmet surface area. -Teller (BET). Ultimately, fuel properties similar to those of mineral diesel are obtained. Represented by Flash point 49, Cetane number 39, Cloud point 7, Calorific value 41 and acid value 0.374.
Duaa Nadheer Abd zaid; Dhafer A Hamzah
Abstract
Tubular heat exchanger (THEX), that has been in numerous engineering applications, represents an apparatus that makes heat to be exchanged between two fluids having different changing in temperatures and kept separated by means of a solid wall. In order to enhance the efficiency of the THEX, the rate ...
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Tubular heat exchanger (THEX), that has been in numerous engineering applications, represents an apparatus that makes heat to be exchanged between two fluids having different changing in temperatures and kept separated by means of a solid wall. In order to enhance the efficiency of the THEX, the rate of heat transfer at the tube side should be improved. Inserting a twisted tape inside the heat exchanger’s tube is one of the passive techniques that has been widely used to improve the heat transfer especially in air conditioning and cooling, processes of power recovery, processes for food and dairy, and plants for chemical processing. The heat exchanger enhancement is achieved by means of using a twisted tape inserted with twisting ratios (TR) equal to 3.2, 4.4, and 5.5, independently. The influences of 2-D parameters such as Nusselt number and frictional coefficient on the THEX’s effectiveness were investigated. The aim of the study is inserting a twisted tape inside the testing pipe to produced turbulent flow and, therefore, creating large turbulence rate inside the pipe that plays an significant role in improving the transferred heat and increasing the drop in the pressure. In this work, the inserted tape has a width and length equal to 21.5 mm and 1000 mm, respectively. The inner and outer diameters of the used pipes were 23 mm and 22 mm, respectively. The tested sectional length of the THEX was equal to 2000 mm. Reynolds number was changed from 500 to 7000. Results obtained from using twisted inserting tapes with varying TR were compared with result from plain tubes. These results were displayed in the contours show the distribution of the temperature and the trajectory of the flow trajectory by axial velocity for testing the low values of Reynolds number applicability in heat exchanger applications
Sahar Hussein Ali; Mohammed Qadir Ismael
Abstract
The Moisture damage is considered as one of the main challenge for the experts in the field of asphalt pavement design. The aims of the present study is to modify moisture resistance of the asphalt concrete by utilizing ceramic fibers as a type of reinforcement incorporated with hydrated lime. For this ...
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The Moisture damage is considered as one of the main challenge for the experts in the field of asphalt pavement design. The aims of the present study is to modify moisture resistance of the asphalt concrete by utilizing ceramic fibers as a type of reinforcement incorporated with hydrated lime. For this purpose, a penetration grade of the asphalt cement (40-50) was utilized as a binder with an aggregate of the maximum nominal size of 12.5mm and mineral filler limestone dust. A series of specimens has been fabricated by utilizing 0.50, 1.0, 1.5, and 2.0 percentages of ceramic fibers. For each of these contents, another subsequent group of specimens with hydrated lime with 0.0, 1.0, 1.5, and 2.0 percentages were moulded. For the addition of ceramic fiber and hydrated lime to the mixtures the dry method for ceramic fiber was adopted while for the hydrated lime, the saturated surface dry method was adopted. The results of this study have shown that the addition of 1% ceramic fiber with 1.5% hydrated lime recorded the highest levels of growth. Furthermore, the outputs of the tests used in this study have shown that the use of ceramic fibers resulted in a growth in the value of tensile strength ratio (TSR) and in the index of retained strength (IRS) compared with the control mixture. Maximum values for TSR were achieved at 1% ceramic fibers with 1.5 % hydrated lime.
Dhuha Jawad Hussein; Mohammed Ali Mutar
Abstract
The purpose of the present work is to designate the synthesis of innovative soft silicone hydrogel contact lenses founded on Acrylic acid (AA) ,N,N dimethylacrylic amide (DMA),and 1-vinyl 2- pyrolidone(NVP) was polymerized via free fundamental polymerization in the existence of 1,6 hexandioldiacrylate ...
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The purpose of the present work is to designate the synthesis of innovative soft silicone hydrogel contact lenses founded on Acrylic acid (AA) ,N,N dimethylacrylic amide (DMA),and 1-vinyl 2- pyrolidone(NVP) was polymerized via free fundamental polymerization in the existence of 1,6 hexandioldiacrylate (HDODA) as a crosslinker and 1-hydroxycyclohexyl phenyl ketone as photoinitiator. The polymerized materials were characterized fully for its use fullness as an intraocular lens by various techniques. FTIR was implemented to discover the whole conversion of3-(methacryloyloxy) propyl TRIS (trimethylsiloxy) silane monomer into silicone hydrogels contact lens. The silicon hydrogels contact lenses were manufactured from silicon and different hydrophilic monomers, copolymerization of 3-(methacryloyloxy) propyl( TRIS) (trimethylsiloxy) silane with acrylic acid ,N,N-dimethylacrylamide, and N-Vinylpyrrolidone(NVP) with different ratio (70,80,90)%.To explore three sequences of silicone hydrogel ingredients for their classification, water component, transmittance, mechanical feature , oxygen penetrability) Dk), protein adsorption and bacterial connection as potential contact lens materials as well as tackles the connections between water kinship and optical, mechanical, oxygen permeable with biological features.The outcomes displayed that the water affinity might be moderated through the hydrophilic monomers. The Equilibrium Water Component (EWC) rose with increasing hydrophilic monomer value. Generally, the outcomes revealed that visible light transmittance inclines to increase as well as tensile mechanical features obtained in decreasing trend relying on the growing EWC. The Dk worth declined firstly then was rose once the EWC was from 25 to 75%. The sum of Staphylococcus aurous close to the silicone hydrogels surface of the was fell by61 to 140.This work may provide information on preparing functional silicone hydrogels for contact lenses application.
Mushtaq Albdiry; Fouad K. Mahdi; Abbas A. Diwan
Abstract
In this study, a bimetallic CoMo spicy supported on γ-Al2O3 heterogeneous catalyst was successfully prepared by an incipient wetness impregnation for Hydrodesulphurization (HDS) reaction of An-Najaf oil refinery heavy naphtha. The structural characteristics of the prepared 5Co-15Mo/γ-Al2O3 catalyst ...
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In this study, a bimetallic CoMo spicy supported on γ-Al2O3 heterogeneous catalyst was successfully prepared by an incipient wetness impregnation for Hydrodesulphurization (HDS) reaction of An-Najaf oil refinery heavy naphtha. The structural characteristics of the prepared 5Co-15Mo/γ-Al2O3 catalyst were evaluated by Scanning Electron Microscopy (SEM) and X-Ray Powder Diffraction (XRD) spectroscopies. The surface area, pore volume and pore size were determined by a Brunauer–Emmett–Teller (BET) method. The catalytic activity in the removal of sulphur compound from a heavy naphtha through the HDS at four different reaction temperatures (523, 548, 573, 598 °K) and four different liquid hourly space velocities (3, 4, 5, and 6 hr-1) under a constant ratio of 150 mL H2/1 mL naphtha and a hydrogen gas pressure of 1.5 MPa, has revealed that the prepared catalyst was efficient to remove 82 % of sulphur at 598 °K temperature and 3 hr-1 time. The enhanced selectivity of the CoMo/γ-Al2O3 catalyst through a hydro-treating reaction ascribes to the bimetallic-support interaction and the dispersion of MoS2 particles that leaded to a large edge-to-corner ratio of CoMoS slabs.
Noor Ali Fakher; Mohammed Kadhim Fakhruldin
Abstract
Reinforced soil technology is considered one of the most important methods of soil improvement due to its simplicity, easy implementation and saving cost. One of the known soil reinforcement methods is using geogrids to improve the bearing capacity of the soil and reduce the settlement of the soil beneath ...
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Reinforced soil technology is considered one of the most important methods of soil improvement due to its simplicity, easy implementation and saving cost. One of the known soil reinforcement methods is using geogrids to improve the bearing capacity of the soil and reduce the settlement of the soil beneath foundation. In this study, a strip foundation made of a rigid stainless steel with dimensions of 490 mm length, 135 mm width, and 40 mm thickness and reinforced with geogrid (called Tensar SS2) was tested in a laboratory model to investigate the effect of the number of reinforcement layers on the bearing capacity and settlement. The soil was reinforced with one, two, three, and four layers of geogrid (Tensar SS2). The obtained results showed that the reinforcement using geogrid system significantly improved the bearing capacity while reducing the settlement under the strip foundation compared with unreinforced soil. The test result also showed a good improvement in the bearing capacity when the number of reinforcement layers increased from one to four layers. The bearing capacity of the foundation increased when the soil reinforced by four layers of geogrid to about 2.5 times compared with the case of one layer of geogrid. In addition, the maximum settlement decreased to about 2.0 times compared with the case of one layer of geogrid.
Abbas Fadhil; Sarah Abdul Hussein Mandeel; Haider M. Mekkiyah
Abstract
The bearing capacity of layered soil studies was carried out with various approaches such as experimental, theoretical, numerical, and combination of them. This work is focused on the settlement and bearing capacity of shallow foundations subjected to the vertical load placed on the surface of layered ...
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The bearing capacity of layered soil studies was carried out with various approaches such as experimental, theoretical, numerical, and combination of them. This work is focused on the settlement and bearing capacity of shallow foundations subjected to the vertical load placed on the surface of layered soils. The experimental part was performed by manufacturing soil cubic container (570 mm x 570 mm x 570 mm). A model square footing of width 60 mm was placed at the surface of the soil bed. The relative density of sand was constant at 60%, and the clay was prepared with a density of 19.2 (kN/m3) and water content of 14.6%. PLAXIS 3D FEM was used to simulate the experimental tests and performing a parametric study. The results showed that there was a good agreement between experimental work and corresponding numerical results. The value of the bearing capacity was obtained from load-settlement curve. The bearing capacity of layered soil showed higher value for footing resting on clay over sand soil. It was found that an increase in the ultimate bearing capacity regarding the clay over sand with increasing in first layer thickness ratio; while, a decrease has been indicated for the sand over clay. The critical depth was found at H = (2-3m), and the failure pattern was not unique for layered soil.
Mujtaba Abdulkadhim Alkafaji; Mohsin N. Hamzah; Jafar M. Hassan
Abstract
The hydraulic system plays an important role in the design of many mechanical devices due to its high power to weight ratio. In this work, a theoretical study of a hydraulic stimulator was performed to conduct suspension tests in a quarter car in the laboratory. Due to high nonlinearity in the hydraulic ...
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The hydraulic system plays an important role in the design of many mechanical devices due to its high power to weight ratio. In this work, a theoretical study of a hydraulic stimulator was performed to conduct suspension tests in a quarter car in the laboratory. Due to high nonlinearity in the hydraulic systems, a robust controller based upon integral sliding mode (ISMC) with nonstandard backstepping was used to perform the tracking process of the hydraulic actuator to the required road profiles. The controller design divided into two parts: the first part deals with the generation of the ideal control force which satisfied all the tracking requirements by using ISMC. The second part of the controller is the replacing of the ideal control force with the actual hydraulic force with all parameters by using nonstandard backstepping control. The effectiveness of the exciter control system was performed by using two road profiles i.e. Bump road profile and random road profile.
