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Go to Editorial ManagerAdvanced applications, such as aircraft manufacturing, require sophisticated materials. Composite materials are among these advanced materials and offer several advantages, including high strength and low weight. Given that these applications experience repeated loading, studying fatigue in composite materials is essential. This paper provides a comprehensive review of fatigue failure in composite materials, focusing on the types of fatigue loads, the characteristics of composite materials, and the damage mechanisms. Additionally, we discuss modelling and simulation techniques to understand fatigue behavior and the standards necessary for conducting fatigue failure testing in composite materials. The study of fatigue in composite materials is diverse, reflecting the materials' complexity, which varies across scales. Due to composite materials' heterogeneity, numerical modelling can be challenging. It often requires numerous constants that change with various factors, which can only be determined through experimental test. As a result, studying fatigue in composite materials can be costly.
This study focuses on the design and construction of an automated device for evaluating the scratch resistance of polymeric materials by measuring the force required to produce surface scratches and calculating the corresponding friction coefficient from device input–output data. The device was fabricated using locally available materials, with several components manufactured in local mechanical workshops. It comprises four main subsystems: mechanical components, scratching mechanism, electrical and electronic units, and an operating control program. The developed device offers the following specifications: normal load range of 0.1–325 N, sliding speed of 1–35 mm/s, tangential force measurement capacity of 0.1–294 N via a load cell, sample dimensions of 10–195 mm in length, 10–125 mm in width, and 0.25–50 mm in thickness, a maximum scratch length of 195 mm, and an adjustable indenter height ranging from 0.25 to 50 mm above the platform surface. Scratch testing and friction coefficient measurements were conducted on pure PMMA and PMMA reinforced with silicon dioxide (SiO₂) nanoparticles. Experimental results demonstrated increased scratch resistance and reduced friction coefficients with higher SiO₂ weight ratios. Additionally, the performance evaluation confirmed that the designed device is capable of accurately and rapidly measuring the tangential forces associated with scratching through a simple operational procedure.
The thermoelectric behavior of different materials under various conditions has been investigated numerically by using the heat transfer module of the COMSOL Multiphysics software platform. A simulation study of the thermoelectric materials (TEM) performance was created by altering the current applied from 0.1 to 1.0 A and setting the hot side temperature (T H ) as 273 K. The impact of different performance metrics, such as cold side temperature and output voltage, has been proven and investigated. It has been shown that the material of the thermoelectric legs', length of leg, and thickness of electrodes significantly impact the thermal and electrical performance of the thermoelectric (TE) module. Appropriate ranges have been studied in the simulation, such as the amperage values applied to the unit as mentioned above, the length of the leg within a range of 1 to 8 mm, and the thickness of the electrode with different values of 0.1 to 0.5 mm, which will achieve excellent performance for the Thermoelectric unit. Modeling and simulation results demonstrated and revealed the optimal and potential use of bismuth telluride (Bi 2 Te 3 ) as well as lead telluride (PbTe) as suitable for Peltier cooling applications. As for the use of cobalt triantimonide (CoSb 3 ), it is in contrast to the two previous metals, as it is effective and appropriate if applied to power generation. The results are validated with another study from the literature, and there is an excellent agreement with an error rate that does not exceed 0.164%.
It is very crucial to minimize the environmental impact that induced from the development of industry, by applying strict policies and innovate eco-friendly industries. Indeed, construction manufacture considered as one of the most industries that affect the environment, especially concrete production and usage in structural buildings. For instance, traditional concrete, which is consists of a high amount of cement, is contributed to the emission of CO 2 . Therefore, researchers seeking to develop a new technology of concrete by replacement some amount of cement by materials which are considered to become more friendly to the environment. Nowadays, this new technology is known as Green Concrete. The importance of using green concrete is not only to decrease the emission amounts of CO 2 but also to replace cement by industrial waste. In this paper, a review has been presented to understand green concrete benefits and materials that may be used instead of cement and aggregate.
The effect of different dosages of the high range water reducing admixture–additive- (HRWRA), the commercially polymeric material (Plastocrete-N), on the corrosion resistance of embedded steel in concrete exposed to chloride solution in the absence and presence of sulfate ions was studied. In the present study, four levels of polymeric material (Plastocrete-N) (0.125%, 0.250%, 0.375%, and 0.500% by weight of cement) were used to prepare HRWRA treated concrete. The concrete specimens exposed to chloride and chloride–sulfate solutions at concentrations of (3.5% NaCl and 5% Na2SO4), at ambient temperature. The electrochemical behavior of steel in both reference and HRWRA concretes was studied under the effect of corrosive environments using corrosion measurement systems such as: a) half – cell potentials measurement system and b) accelerated corrosion test system. The results showed that a longer time of corrosion initiation (180 day) observed with 0.500% HRWRA containing concrete compared to other different HRWRA percentage including the reference concrete. It was concluded that the use of 0.500% HRWRA provided superior protection to steel reinforcement in concrete that subjected to corrosive environments. Furthermore, the steel with 0.500% HRWRA was subjected to corrosion test by mass loss, it is evident that a reduction in mass loss by about 90.2% and 85.2% in both solutions, respectively.
This article provides an overview of the studies that have been conducted on the characteristics of epoxy resins containing various types of silica nanoparticles and microparticles, as well as their performance in the industrial application of functionally graded materials (FGMs). Silica nanoparticles and microparticles are used to create epoxy resins in order to improve various properties, such as thermal stability, adhesiveness, electrical conductivity, strength, modulus, and toughness. This review examines the literature that has been published in the last decade, compares the results, focuses on the mechanical and thermal properties, and discusses the changes that have resulted in improvements in those properties. Previous experimental findings are presented and contrasted to demonstrate the extent to which silica filler content contributes to improving the properties of composite materials. The findings reveal that the characteristics of epoxy compounds can be improved by adding a particular amount of silica particles. There is a correlation between an increase in the silica amount and an increase in the Young modulus of epoxy compounds, this correlation becomes stronger as the silica amount increases. Additionally, the tensile strength of epoxy compounds increases to a certain limit as the amount of silica nanoparticles increases. In contrast, the hardness of the material increases as the silica amount increases. The density of the material also increases steadily as the silica amount in the material increases. According to thermal analysis results from calorimetric research on epoxy–silica systems, the glass transition temperature increases as the silica amount increases.
This study investigates the deep drawing process of carbon fiber-reinforced high-density polyethylene (CF-HDPE) composites through experimental and numerical approaches. The experimental part involved fabricating CF-HDPE sheets and conducting deep drawing operations under controlled parameters (punch speed, temperature, and forming depth) to evaluate material behavior and mechanical properties. Numerically, finite element analysis (FEA) using ABAQUS simulated the forming process, analyzing stress distribution, strain development, and material deformation under varying conditions. Results revealed that increasing forming depth and decreasing forming temperature elevated the required forming force. Comparisons between experimental and numerical outcomes showed consistent trends, though some differences arose due to factors like friction and material nonlinearity. The findings contribute to optimizing deep drawing processes for composite materials, enhancing manufacturing precision, and minimizing material defects.
Nanoparticles show mechanical, electrical, chemical and optical properties that are different and superior to bulk materials. In the present work, α-Alumina nanoparticles were synthesized using the nonorganic Sol-Gel method under controlled conditions. Because of the low cost of its raw materials, low manufacturing temperature and the high purity of the product, Sol-Gel method is the best in the manufacture of nanostructures like metal oxide nanoparticles. The precursor of the Sol-Gel process was aluminum nitrate with ethanol. The prepared nanopowder was evaluated by X-ray diffraction (XRD), scanning electron microscope (SEM), electron dispersive spectroscope (EDS) and Malvern Zetasize analyzer.
The functionally graded beam is a wide field of research, which attracts great interest today in the field of engineering, science, and medicine society. This type of beam is made from functionally graded material that is characterized by several properties one of them is the high strength to weight ratio. In the current years, this beam has witnessed great developments in the mechanism of its composition and the materials used in its manufacture. This research provides an overview of the properties, types, advantages and challenges, and applications of the functionally graded materials. In addition, this paper review provides a summary of the analysis of bending and buckling that occurs on the functionally graded beam with and without crack effect from (2008-2021) year. Through this review, the following was noted: Firstly, a small number of researchers have worked experimentally, and the properties of a beam in most of the research are gradual towards thickness using the mixing rule. Secondly, the crack has a very severe effect on the behavior of both bending and buckling for the graded beam. This critical review can be considered a milestone in future analyzes of the graded beam and is also beneficial to designers and researchers working in this field.
The present work includes a study on the effect of loading rubber waste into cement mortar on the thermal and mechanical properties of a thermal insulator.The experimental work of the study included the preparation of ten models of 35 mm diameter and 5 mm thickness. Portland cement and natural sand were used as a matrix and rubber waste (extracted from the consumed tires) as a filler was added in weight percentages ( 5% ,10% ,15% ,20% ,25% ,30% ,35% ,40%,45% and 50%). Water was also used as a binder.Also, the experimental work included conducting a thermal conductivity test using Lee’s Disk method, and a hardness test using the Shore scale. The theoretical side included extraction of empirical equations, depending on the experimental results. The thermal conductivity equation was for two variables, temperature and mass fraction. While the hardness equation was for one variable, mass fraction. Theoretically determined heat capacity was extracted using the equations of the composites. Based on the empirical equations of thermal conductivity and hardness and using the technique of multi- objectives genetic algorithm, the optimum values of temperature and mass fraction were extracted, which achieve the best thermal insulation of the mortar. The results showed a significant decrease in thermal conductivity. The reduction in thermal conductivity was (90.3%) at 5% and reduced to (95.73%) at 50%. The specific heat capacity was increasing as the percentage of rubber waste increase. The results also indicated a decrease in hardness. The optimal value of thermal insulation was (0.02658 W/m 2 .ºC ) as a thermal conductivity and (58.07 N/m 2 ) as a hardness, at temperature (50°C) and mass fraction (27.764%) of rubber waste.
Human beings are facing an unprecedented rise in temperature rates not recorded for years. HVAC (heating, ventilation, and air conditioning) systems have been created and enhanced to solve this issue. Cooling load must be estimated with accepted methodologies before designing an efficient and effective air conditioning system. Companies, researchers, institutions, and others advise and develop many cooling load calculation methods. Each one of these methods has its advantages and disadvantages and may give a slightly different result for the same case. For each building, whether it was residential or commercial buildings, gyms, or shopping malls, before making the decision on (HVAC) systems to be used, both heating and cooling loads should be obtained as correctly as possible to minimize expenses as possible. Since the HVAC system consumes the most energy in an air-conditioned building, an accurate method of cooling load estimation is necessary. Consequently, an energy-efficient air conditioning system reduces greenhouse gas emissions into the atmosphere while also saving money on electricity. Two cases have been compared and studied, one in Dubai UAE, and the other in Baghdad Iraq. Three different methods, HAP, hand calculation method (CLTD/SCL/CLF), and MS-EXCEL E20 form sheet were used to compare the accuracy of the results for cooling load. Results of E20 and HAP are very close to each other with high accuracy for peak load, the big difference can be found between the CLTD method and the other two methods. The value of the maximum difference percentage was found between CLTD and E20 equals 3.28% and 7.96%, on the other hand, the lowest difference was equals to 0.3% and 1.51% between HAP and E20 results for Baghdad and Dubai respectively. Traditional and local materials came from local factories, used in buildings played a big effect on the results, which may not match those materials stated in the ASHRAE or CARRIER tables, which need to be considered in the results and calculation procedure. However, all methods have a percentage of difference but all results are within the accepted range and are applicable for practical cases. Of course, this percentage is minimal with some methods and maximum with others.
Single roll melt spinning is a non-conventional forming process used to produce rapidly solidified thin ribbons as a near net shaper by direct casting from liquid state. In this paper, single roll made from brass with a diameter of 150 mm was used to produce rapidly solidified Al-Mg alloys ribbons. The ribbons are produced with thickness in the range of 20 to 330 µm. The results exhibited unique advantages in refining the microstructure, and modifying the mechanical properties of these ribbons. The hardness was improved to about twice the original hardness of alloy. Moreover, corrosion resistance of alloy was improved and their rate was redcued from 10.02 to 1.643 mpy for alloy type 5052 and from 6.91 to 1.943 mpy for 5083.
Pipelines are one of the most convenient and effective ways of transporting petrol over a long distance. The environment applies, beyond extremely high external pressures, low temperatures and intensive corrosive process, the occurrence of defects on the pipe body, which compromises the structural integrity of pipelines leading to catastrophic failures. The main modifications concern the mechanical resistance, toughness at low temperatures weld ability and resistance to embrittlement related to hydrogen. Among mechanical characteristics, the fracture toughness is very important for pipeline steels in design and safe assessment. Aiming to enhance the reliability and operation of complex pipelines system, a study based on the mechanics of the elastoplastic fracture in order to determine better prediction of the fatigue life. The materials tested here are API 5L X42 and X52 micro alloyed steels, as well as to evidence the toughness resistance of these materials. Results indicated that both X42 and X52 steel behave in a similar way and in all cases a slight increase of the transition temperature was found. The characteristic toughness value shows an evident loss in mechanical performances if compared to the uncharged one.
The aim of this research is to predict the shrinkage defects in Al-Si castings by determination the suitable parameters and techniques which can be applied in casting simulation system. Also, it aims to specify the role of silicon content in amount, morphology, and distribution of these defects. The Numerical solution has been carried out using an explicit 3-D finite difference method for the given system of the casting and a mold. Additionally, an experimental casting of the studied samples was achieved. It was found that the shrinkage porosities increased with increasing the silicon content up to 7%, so at this peak, they spread in alt cast regions and cannot be predicted. The low silicon alloys suffered from only the shrinkage cavities defects that can be predicted by mapping the solidus time contours. Finally, it was concluded that the critical temperature gradient value of the porosities development in the eutectic (AI-12%Si) alloys was 1.3°C/cm.
Friction stir processing is a new method of changing the properties of a metal through intense, localized plastic deformation ,this process mixes the material without changing the phase (by melting or otherwise) and creates a microstructure with fine, equiaxedgrains, It is used to improve the microstructural properties of metals. In this paper, the enhancement of mechanical propertiesof friction stir welding specimens at variable rotation speeds (1100, 1300 and 1500 rpm) with constant feed speed (60mm/min) for 6061-T6 aluminum alloy is studied by using the friction stir processing method at the same variable rotation speed and feed speed in order to transform a heterogeneous microstructure to a more homogeneous, refined microstructure. The best results of the welding line at the parameter 60 mm/min weld speed and 1300RPM rotation speed for the friction stir welding (FSW) and friction stir processing (FSP) where the efficiency reaches to 84.61% for FSW and 89.05% for FSP of the ultimate tensile strength of the parent metal.
Solar energy can only be used when it's sunny outside. Therefore, solar heating is only efficient during the day and decreases at night or on overcast days. Consumer energy needs have a distinct seasonal structure, and solar energy cannot completely meet those needs. In order to satisfy customer demand, energy storage is essential. In order to maximize the use of solar energy and to increase the energy and efficiency of the solar absorption system, superior thermal properties of sophisticated materials, such as phase change materials, are important [1]. In the current study, 20 kg of phase change material (PCM) is integrated with solar water heating and fed into a storage tank to enhance the solar water heating efficiency. Helical coil heat exchangers were added to the storage tank as an external load. The trials were conducted in four separate months (September 2021, April, May, and June 2022) that were chosen on the first day. The effectiveness, heat gain, and significance of the phase change material in increasing heating efficiency throughout the day were studied using a range of variables, including water volume flow rate (2, 3, 4, 6, and 8 L/min) and inlet water temperature (25, 30, and 35 °C). The results showed that, given an initial temperature of 25 °C, the daily efficiency range, was 0.58 to 0.65, and that the daily final outlet temperature was enhanced outlet temperature over 65 °C. Additionally, on all test days, the heat released by the phase change material was audible in the evening and increased the utilization time.
A composite beam is an accumulation of different materials so as to form a single unit to exploit the prominent quality of these materials according to their position within the cross-section of the composite beam. The present study investigates the structural behavior of six simply supported composite beams, in which a reinforced concrete T-beam is connected together with a steel channel located at the bottom of a T-beam by means of headed stud shear connectors. The used degrees of shear connection are (100%, 75%, 50%, and 38%). Three dimensional nonlinear finite element analysis has been used to conduct the numerical investigation for the general behavior of beams which are subjected to central point load. ANSYS 12.1 program code was used to estimate the ultimate loads, deflections, stresses, strains, end slip. Concrete was modeled by brick element (SOLID65), while the steel channel was modeled as brick element (SOLID45). Two-node discrete elements (LINK8) are used to represent the steel reinforcement and shear connectors. Perfect bond between the reinforcing rebars and the concrete was assumed. The load on beams was applied monotonically in increments up to failure. The reduction of the degree of shear connection from 100% to 38% causes increasing of strain, mid span deflection and end slip with an average of 3.95%, 13%, and 111% respectively, while the ultimate load decreases with an average of 7.3%. In order to observe the efficiency of the 3-D model, a comparison was made with available experimental work. Good agreement was obtained throughout this work between the finite element and available test results.
The aim of this study is to investigate the effect of heat treatments on the impact properties of hot rolled high strength steel and describes the effect of tempering temperature and quenching media on the microstructure, hardness, and impact resistance of plates. In the present study a high strength steel was austenitized at 900 °C with different quenching medium and followed by tempering at 300 °C, 500 °C. After thermal treatments, the values of Charpy impact resistance, hardness, and microscopic structure were evaluated from mechanical and metallographic analysis of metals respectively. The change of mechanical properties and microstructure of the metal with the existence of heat treatment with the ballistic performance of high-strength steel. Experimental results showed that tempering at 500 °C for 2 hours after water quenching medium it provides the best mechanical properties in conjunct on with an improved in microstructure.
Adhesives have been around for millennia. Nevertheless, this technique for joining has only seen significant development within the past 70 years. Professional technical engineering applications primarily use adhesives derived from synthetic polymers, a development that dates back to the mid-1940s. Its characteristics facilitate their strong adhesion to most substrates, as well as their ability to transfer substantial loads. This paper presents an extensive assessment of the current knowledge in the field of adhesives and related technologies, with a focus on adhesion theories and their parameters, as well as designing, joint configuration, geometric aspects, and failure modes. The paper also explores the interplay between research and development efforts, industrial standards, and regulatory aspects, with the goal of fostering collaboration between academia and industry. Over the past years, the development of new materials, methods, and models has resolved many of the shortcomings. Nonetheless, it is still possible to evaluate and estimate the optimal combination of aspects that will give the greatest efficiency and performance for adhesive bond joints (ABJs).
The study focuses on using sand and activated carbon filters for treating of A l-Kasak refinery wastewater. The wastewater contains many contaminants and organic and chemical materials. Many tests were performed such as pH, E.C, T.S, COD, BOD, Phenole, Oil, and NH3, after and before treatment with a filter in order to determine effluent characteristics. The highest T.S removal efficiency with sand filter was 93% and 90% for oil. The highest removal efficiency with activated carbon filter happened to Phenol, which was 99%, and for COD and BOD was(81- 90) % and (77-9 1)% continuously. The study shows that the cycle time of 9 hr gives the best removal efficiency for organic wastewater, especially for high organic load. It was recommended to use a sand-activated carbon filter to treat refinery wastewater because the effluents were within the Limits of refinery waste water casting and river casting.
In this research, the mechanical properties were studied from the experimental, theoretical, and numerical aspects of the sports prosthetic foot for the purpose of providing a sporty prosthetic limb with high performance, easy to use and an appropriate financial cost to use by amputees who have lost their lower limbs (amputation below the knee) in practicing their sports activities and overcoming physical disability. The dimensions of the blades were calculated based on side profiles from European patent specifications. The chosen fibers have high strength, are light in weight, and can be purchased for a lower price than the materials that are used in the production of the sports prosthetic feet that are already on the market and are produced by specialized companies such as Ottobock and Ossur. Six laminates of the composite material consisting of matrix orthocryl lamination 80:20 pro reinforced with different fibers (Kevlar fibers, carbon fibers, glass fibers, and perlon fibers) were fabricated in the form of rectangles using the vacuum system and then cut to the required dimensions using a CNC machine. The density and volume fraction of the samples and the use of the rule of mixtures to calculate the mechanical properties of the laminates were calculated and entered into the ANSYS program. Then the boundary conditions were applied to the athlete's prosthetic foot and the total deformation, and the total strain energy was calculated to find out the best laminates in the athlete's foot industry. It was noticed that the laminates reinforced with carbon fibers were better than the laminates reinforced with glass fibers in terms of Young’s Modulus, as well as deformation. The best laminate obtained is (12 K + 4 C).
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
In the sustainable dwelling, in all its formations whether at the urban or architectural level, the effects of the surrounding environment are taken into account in the design process, starting from the distribution of residential functions, the form of the dwelling, or even the structural materials used in its formulation, in addition to the technological dimension, not to mention the site and its effects as well as the consumed energy and its effects. The study proceeds with research and analysis to build a comprehensive strategy for the problem related to the harsh climate of the region, and its negative effect on residential formation, by activating ideal solutions to those problems according to the principles of environmental sustainability. The concept of the new healthy dwelling in its proposed form addresses the benefits that sustainable environmental formation can offer in improving the conditions of thermal comfort within architectural spaces and then designing a new form of housing under the name of passive energy bio-climatic formation systems. Its ideas must be subject to the wisdom of the architect through passing over all effective strategies that help create the maximum material comfort and thus reduce high environmental costs.
Solar desalination uses solar radiation to convert saline or seawater into clean water and is increasingly crucial due to growing pollution from industrial and automotive sources. Although solar stills offer a sustainable solution, they face challenges in terms of production efficiency. This study presents a new structural design for solar stills, which incorporates advanced insulation materials, a well-designed distillate channel, and an inclined base to enhance productivity. The research explores how different climatic conditions such as wind speed, solar radiation, and atmospheric humidity affect solar still performance. Seven experimental setups were evaluated, comparing traditional inclined stills with advanced closed-loop systems. The results demonstrated that closed-loop systems improved productivity by 28.6% compared to open-loop systems. Additionally, moderate wind speeds increased productivity by 20.82%, while partial cloud cover and light rain decreased productivity by 52.15% and 12.9%, respectively. However, light rain also enhanced condensation efficiency by cooling the glass surface. This study highlights the importance of incorporating environmental factors into the design and optimization of solar still systems for improved performance.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The effect of thermal aging on the tensile properties of cast stainless steel during service in light water reactors has been evaluated and recorded by the Argonne National Laboratory. Tensile data for several experimental and commercial heats of cast stainless steel (CF-8M) are presented for predicting the change in tensile flow and yield stresses and engineering stress-strain curve as a function of time and temperature of service in the light water reactors using Neural Networks. Thermal aging increases the tensile strength of this type of steel. The result and correlation described by this work may be used for assessing thermal embitterment of cast stainless steel components.
In several countries, residential buildings are responsible for high energy consumption. The majority of energy is consumed on air conditioning to ensure maximum indoor comfort. In Iraq, the demand for electricity increases significantly, especially during the summer for cooling purposes. In this paper, two technologies are proposed for buildings to reduce the cooling load. These approaches included the use of phase- changing materials (PCM) in different locations in the walls and roof, in addition to roof shading by galvanized iron. The effects of these proposals were simulated in the latest software tool (designbuilder) and compared with the standard building model. The results were clear when PCM was installed on the outer surface of the wall and roof, which achieved the highest reduction in the cooling load of about 18 %. While the roof shading method using corrugated galvanized iron proved its effectiveness by decreasing the cooling load to 5 % compared to the standard case.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
In this study the powder metallurgy technique was used to prepare the composite materials using the aluminum powder as the basis metal, with the additions of the 2, 4 and 6%Wt. of ZrO2-Cu coating and mixing it manually for 15 minutes at (30-32 oC). Then the mixture are compacted at pressure 320 MPa and sintering at 640oC in the atmosphere furnace with argon gas protection. The physical properties include the green density, sintering density, porosity, and microstructure were examined for the prepared samples. X-ray analyzer was used to identify the phases changes in order to find the chemical reaction which it can be excepted occurred in the sintering samples. The result of X-Ray diffraction shows that there is new phase exist after sintering for all weight percentage.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
A series of unconfined compression and direct shear tests were carried out to investigate the compressive strength and shear strength parameters of clay soil reinforced with different contents and lengths of wheat straw and palm frond fibers and by adding different percentages of furnace slag. The bearing capacity and settlement characteristics of the rectangular footing based on a clay soil layer reinforced with wheat straw fibers, palm fronds and furnace slag at different thicknesses were also studied by conducting model footing tests. The results indicated that the compressive strength and shear strength parameters improved significantly when adding 0.5% of natural fibers and 20% of furnace slag. The maximum compressive strength of soil samples reinforced with wheat straw fiber MT1 and palm frond fiber MT2 was 365 and 407 kPa, respectively. Compared to the unreinforced sample, samples reinforced with natural fibers and furnace slag significantly improve the shear strength parameters c and ϕ . The cohesion of soil sample reinforced with wheat straw and palm frond fibers increased by 8% and 43% respectively, while the internal friction angles improved by 19% and 40% respectively. The sample treated with furnace slag MT3 showed improved significantly in cohesion by 76% and less effect in internal friction angle. Compared to unreinforced soil samples, the cohesion of soil samples reinforced with wheat straw and palm fibers and treated with furnace slag MT4 and MT5 increased by 77% and 92% respectively, and less effect in internal friction angle. Moreover, the bearing capacity and settlement characteristics of the rectangular footing improved significantly with the increase in the thickness of the top layer reinforced with natural fibers and treated with furnace slag. The ultimate bearing capacity of layer reinforced with wheat straw fibers MT1 increases to 193.2, 220.15 and 247.5 kPa at thicknesses of 0.5 B, 1.0 B, and 1.5 B respectively, while the settlement decreased by 10.4%, 15% and 20.48% respectively at same thicknesses.
This research makes a two-dimensional model for a cold flat rolling process using the ANSYS program. The contact pair is used between the contact surfaces using the boundary condition of the surface-to-surface contact. The process of symmetric rolling is tested for two types of materials (aluminum and mild steel). The rolling force for (1%) to (25%) reduction of a slab of dimensions of (200 * 10) mm using (Avitzur) theoretical equations and ANSYS. The radius of the rolls for aluminum is (75) mm and that for mild steel is (300) mm. The numerical results were compared with (Avitzur) theoretical equations. The comparison shows that the values of forces calculated using (Avitzur) theoretical equations are accurate enough up to (5%) reduction, and the numerical results proved its accuracy up to (25%) reduction. The study shows that forces increase as a result of increasing the rolling metal area at the entry rate. The angle of the neutral point was also studied in this work and it is found that it decreases with the increasing reduction rate, due to an increase in the cohesion area on the sliding one within the rolling process while the theoretical results failed to calculate the angle of the neutral point correctly.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The present work is aimed to reduce the annual electric energy consumption in a residential building in Basrah city through introducing a standardized rule for the annual electrical consumption for the cooling and heating purposes. This work will concentrate on all parameters which help to go toward the optimum use of thermally efficient house. The building energy analysis program e-Quest was used to simulate the annual energy consumption for a typical residential house built with different types of building materials. Transfer function cooling load calculation was used. The results showed that for the Base- House, the thermal transmission through the walls and roof constitutes more than half of the total peak cooling load. It was found that a house built with thermo-stone causes 5.9% reduction of the annual cooling energy consumption, and 12.4% in the annual heating energy consumption. However, insulating the Base- House causes a significant reduction in the air conditioning equipment capacity and consequently reduction in cooling energy consumption by 23%, and reduces the heating energy consumption by 42.8%. Finally this work presents a useful planning to developed building design which reduces the electrical energy consumption.
The goal of this study is to evaluate the mechanical characteristics and energy absorption capabilities of both closed-cell pure Aluminum foam and closed-cell A356 foam. A portion of the lightweight pure foam samples (17.12, 17.77 and 15.27 g) is produced through casting of raw material (99.9 % pure aluminum) using Titanium Hydride (TiH 2 ) as a foaming agent, which lead to (7.5, 7 and 8) Pores Per Inches (PPI); and samples of A356 foam (38.24, 38.18 and 35.88 g) is produced through casting of A356 alloyed material with same procedure which lead to (11, 10 and 12) PPI. In order to determine the maximum compressive strength, strength-to-weight ratio, energy absorption density, complementary energy, and energy absorption efficiency, a uniaxial compression test is conducted. The results indicate that compression of pure foam structure smashed in a ductile manner and shows a lamellar eutectic structure while A365 foams under compression are crashed with brittle character with complex phases distribution inside (polyhedral and globular morphologies), A noticeable enhancement is observed in the mechanical characteristics of the A356 foam. The maximum compressive strength and specific energy absorption of alloyed foam are increased by a factor nearly of 4 and 2 respectively for all tested samples. Also, the result shows a significant decreasing in compressive strength with increasing of PPI for both pure and alloyed foam. The notable enhancements in the properties of alloyed closed cell foam render these advanced materials a viable option for high-strength applications.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
This paper is concerned with a stress analysis in a bearing under unbalanced fon:es of the jownal. Some aspects of mathematical modeling of rotating structW'Cs were considered. "Finite Element Method'' is fom1ulated for modeling rotating structures. As an application, a test rotor mounted on two-lobe hydrodynamic bearings is presented. Unbalance response calculations for various unbalance magnitudes are ca1Ticd out in the bearing location. The bearing coefficients were found at rotational speed of 4,000 rpm. An accurate identification of bearing force parameters, i.e. stiffness and damping coefficients is presented by a classical linearized model. The bearing support forces in tlexiblc rotor-bearing systems are presented as a function of unbalance response of the journal. The calculation of the bearing stress due to rotor w1balance are carried out using ANSYS. The ANSYS program gives a good aids in understanding the ~tress analysis in the bearing under the action of journal rotation.
This paper demonstrates experimental and numerical studies to investigate in perforation pipes with a phasing 180° and perforation densities 9 spm in a horizontal wellbore. The experimental study was conducted to investigate the phasing angle 180° in a horizontal wellbore. The wellbore has an inner diameter of 44 mm, as well as the length of the pipe is 2 m. For this purpose, a simulation model was created in the wellbore using the ANSYS FLUENT simulation software by using the standard k - e model and applied to the (CFD) with changing the axial flow from (40 - 160) lit/min and constant inflow through perforations from range (20 - 80) lit/min. Concerning the findings of this study, it was noticed that the total pressure drop (friction, acceleration, mixing) goes high as the total flow rate ratio increases. As well as, an increase of the inflow concerning the main flow rate ratio leads to an increase in the total pressure drop and a decrease in the productivity index. Furthermore, the percentage error of the total pressure drop between the numerical and experimental results in test 4 is about 5.4 %. Also, the average velocity goes high with increasing the total flow rates and the velocity keeps increasing along the length of the pipe until it reaches its maximum value at the end of the pipe due to the effect of the perforations. It was concluded that there are the numerical and experimental results reflected a good agreement concerning the study of the flow-through perforations at 180° angle in terms of pressure drop and apparent friction factor, etc.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
Fracture mechanics approach is important for all mechanical and civil projects that might involve cracks in metallic materials the purpose of this paper is to determine a crack tip opening displacement fracture toughness experimentally, also study the effect of thickness on CTOD fracture toughness of low carbon steel and study the effect of Wire Electrical Discharge Machine (WEDM) to have a pre-crack, instead of fatigue pre-crack by using a CT specimen of low carbon steel with a thickness of (8,10, and15 mm), a width of 30mm, crack length of 15mm, and pre-crack of 1.3mm for all samples, this dimension according to ASTM-E399-13, by pulling the specimen in a 100 KN universal testing machine at a slow speed rate of 0.5 mm/min, the load applied on the specimen is generally a tension load. The crack tip plastically deforms until a critical point P C at this moment a crack is initiated. The computer-controlled universal testing machine gives the value of the load and the displacement transducer gives a crack mouth opening displacement. Critical crack tip opening displacement CTOD is found with the plastic hinge model (PHM) method. The result showed the stress intensity factor K I increases with increased loading in the elastic region and t he thickness effect refers to the effect of the plastic zone at the crack tip on the stress intensity factor, In a thin specimen, a plastic zone is large at the fracture tip leads to a high-stress intensity factor at the fracture tip but in the thick specimen, on the other hand, has a small a plastic zone and a low-stress intensity factor around the crack tip. The fracture toughness is found to increase with an increase in the thickness of specimens.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
This research concerns with the fracture behavior of reinforced concrete beams without shear reinforcement numerically. The software ABAQUS is adapted to simulate the crack propagation using the eXtended Finite Element Method (XFEM), taking into account materials nonlinearities using concrete damage plasticity CDP criteria. XFEM is used to solve the discontinuity problems in the simulation. The maximum principal stress failure criterion is selected for damage initiation, and an energy-based damage evolution law based on a model- independent fracture criterion is selected for damage propagation. The traditional nonlinear finite element analysis is used to specify the crack initiation position, which is required to specify the crack location in the analysis of beams using XFEM. Three-dimensional reinforced concrete beam models are investigated subjected to three and four-point loading tests. Simply supported beams under the effect of applied static load are investigated. An elastic perfectly plastic model is used for modeling the longitudinal steel bars. The main variables considered in the study are beam depth and the shear span with beam length. The numerical results are compared with the available experimental results to demonstrate the applicability of the model. The XFEM provides the capability to predict the concrete member fracture behavior.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
In this paper, a universal testing machine and an impact testing apparatus have been upgraded by using a high- accuracy data acquisition and control system interfaced to a personal computer with proper sensors and actuators. The purpose of upgrade is to increase the accuracy of the measurements and to perform advanced material testing procedures that are not possible with the old configuration. The modernization process not only permits the accurate data acquisition and convenient operation but also the ability to study the effect of strain rate on the tensile properties of materials. Also, an experimental study of the response of CFRP (Carbon Fiber Reinforced Plastic) material to low and intermediate strain rates has been carried out.
Exceptionally strong press-hardened steels (PHS) are significantly demanded in the automobile industry for satisfying the carbon neutrality criterion. Recent research attempts to produce advanced-ultrahigh-strength medium steels have resulted in a variety of alloying approaches, thermomechanical processing techniques, and microstructural modifications for these steel grades. It has been shown that adding microalloying components to standard Mn-B steels can refine the microstructure of PHS which leads to better mechanical properties such as hydrogen embrittlement resistance and other performance indicators for service. In this paper a general review about the effect of microstructure test on the mechanical behavior of Press Hardening Steel (PHS) where microstructure approaches have also demonstrated good potential for the mechanical characteristics of PHS steel, in line with need for new evaluation and discovery meantime, statistical data of the microstructural phases heavily influence the mechanical properties, microstructural image analysis is essential. The purpose of this paper is to know how the microstructure phases will effect on the strength and hardness of press hardening steel also the alloying elements adding impact on the microstructure formulation and mechanical features of PHS.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The incorporation of thermal energy storage materials (TESMs) into solar energy systems is a factor that boosts the performance of these systems. In this paper, an experimental study was addressed for enhancing the heat pipe’s thermal performance that works with an Evacuated Solar Tube Collector with Heat Pipe (ETCHP) as a solar water heater system. This is done by adding micro-zinc oxide (ZnO-MP) to the paraffin wax integrated as TESM into the evacuated tube (ET) of the system, where the evaporator section of the heat pipe is completely submerged within the micro-enhanced paraffin wax. Three experimental prototype rigs with one evacuated tube were designed, built, and tested to do the investigation. The most important parameters that have been studied in this study are the thermal resistance and the temperature distribution pattern along the heat pipe. The results show a clear indication of the decrease in the thermal resistance of the heat pipe of the proposed system compared to the system in which pure paraffin wax was incorporated. Also, it was noticed that there is a significant improvement in the temperature distribution along the heat pipe due to the improvement in the conductivity of the micro-enhanced wax compared to the pure wax.
The investigation of the indoor electromagnetic propagation has been performed at the unlicensed industrial, scientific, and medical (ISM) band, which has gained increased attention recently due to high data rate communication systems developed to operate in it. The effect of the incidence angle and materials thicknesses on the reflection coefficients for both horizontal and vertical polarization has been studied. Two-dimensional ray-tracing model has been suggested to simulate the influence of buildings electromagnetic properties on indoor radio channel characteristics, such as signal level, rms delay spread, and coherence bandwidth. Results show that the influence of the permittivity is more important than the influence of the order of reflection considered for the ray- tracing model. It is also shown that, compared with power level, rms delay spread is more sensitive to the building dielectric parameters. Maximum rms delay spread is dependent mainly on the reflectivity of the walls which dependent on the dielectric parameters.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.