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Go to Editorial ManagerAl2O3 is a major reinforcement in aluminum-based composites, which have been developing rapidly in recent years. The aim of this paper is to investigate the effect of alumina phases and amounts on the physical properties of fabricated Al-Al2O3 composite. Alpha micro and gamma nano of alumina with particle size of 30µm and 20 nm respectively reinforced aluminum matrix of 45 µm. The percentage of reinforcement material were in the range of (5, 10 and 15wt.%) fabricated by powder metallurgy technique. Specimens dimensions were a disc specimens with 11mm diameter and 5 mm thickness. The green density was achieved under compaction pressure of 500MPa, and then sintered under pressure less sintering at 500ºC in a vacuumed tube furnace for two hours Physical properties of the composite samples have been studied such as relative density, sintered density, porosity, microstructure characteristics, particles distribution, agglomeration, grain sizes and granularity accumulation distribution. It has been noticed that at the micro alumina phase, its relative densities are decreased when there is an increase in amount of micro alumina addition, on the contrary in case of nano composites, where the relative density are increasing along with the increase in nano alumina addition. At micro and nano composites, the produced relative densities are less than the pure aluminum relative density. Agglomeration are increasing with the increase in amount of reinforcement, while its more obvious with nano composite. Grain size reduced with the increase in amount of alumina in micro and nano composites, while, the obtained average grain size diameter is less in nano composite than in micro composites. It is obvious from the results that the variation in physical properties and microstructure of Al-Al2O3 composite are depends on both of alumina phases (size) and percentages. At 15wt.% of nano alumina higher relative density and lower porosity will be obtained.
This study focused on the urban transformations resulting from the removal processes taking place in the urban fabric of sacred city centers, under the pretext of increasing urban capacity due to the density of use, which leads to the removal of important parts of the traditional urban fabric and adding them to the public urban space. To determine the amount of usage densities that the area can accommodate represented by the case study, which is the center of the holy city of Najaf: the study was based on using a quantitative measurement approach to test the hypothesis using a multivariable density measurement tool. A space matrix capable of measuring densities, accessibility, and diversity in the fabric during three time periods, a historical period 1900, 1990, and the current time 2024, to know the amount of changes that have occurred in the fabric. A qualitative measurement tool, which is a random sample questionnaire, was used to measure perceived density to find out which fabrics within the city center are more accommodating of congestion. The research has found that high and advanced accessibility through an integrated fabric with high connectivity that makes the city spaces work as one space leads to an increase in flows. It works to reduce the momentum in the city center and thus preserve the traditional urban fabric that must be emptied for pedestrians, as it represents the only fabric with The human scale at the level of the city as a whole (i.e. a fabric that is comfortable for pedestrians) also represents the identity of the area, and to accommodate the densities, the percentage of building density must be increased outside the traditional fabric.
The optimal spacing between finned tubes cooled by free convection is studied numerically. A row of isothermal finned tubes are installed in a fixed volume and the spacing between them is selected according to the constructal theory (Bejan's theory). In this theory the spacing between the tubes is chosen such that the heat transfer density is maximized. A finite volume method is employed to solve the governing equations; SIMPLE algorithm with collocated grid is utilized for coupling between velocity and pressure. The range of Rayleigh number is (103 ? Ra ? 105), the range of the tube position is (0.25 ? ? ? 0.75), and the working fluid is air (Pr =0.71). The results show that the optimal spacing decreases as Rayleigh number increases for all tube positions, and the maximum density of heat transfer increases as the Raleigh number increases for all tube positions and for Ra=105 the highest value of heat transfer density occurs at tube position (? =0.75) while the lowest value occurs at tube position (? =0.25). The results also show that the optimal spacing remains constant with change of the tube position at constant Rayleigh number.
This paper aim to study the effects of earth reinforcement on the stresses generated within a semicircular cross-section tunnel lining buried in sandy soil due to surface loading. The effect of position and number of reinforcement layers was studied. Also, the relative density of soil was investigated. The depth of soil above the tunnel crown was fixed to be three times the tunnel radius. Two relative densities for soil were used, 55.3% and 73.3%. One layer of reinforcement that was used located at distance equal to the radius or two times the radius above tunnel crown. Also, two layers of reinforcement were located at distance equal to radius and two times radius above the tunnel crown. The results show that the use of earth reinforcement will reduce the stresses generated in the tunnel lining due to application of surface loading.
This study explores the impact of adding high-density polyethylene (HDPE) and Novolac polymers to gypseous soil from Tikrit City, Iraq, to enhance its geotechnical properties. The soil contained 38% gypsum, and the polymers were added in varying proportions (1%, 3%, 6%). Both polymers improved maximum dry density, optimum moisture content, and reduced collapse potential (Ic). The collapse potential was reduced by 64%, 77.7%, and 83.2% at 1%, 3%, and 6% HDPE content, respectively. The collapse potential was reduced by 82.3%, 74.8%, and 51.9% at 1%, 3%, and 6% Novolac polymer content, respectively. In the dry conditions, the internal friction angle increased by about 22.9% and 5.7% as the HDPE content was increased by 3% and 6% respectively. Adding Novolac polymer also increased the internal friction angle by about 5.7% by the addition of 3% Novolac polymer. In soaked conditions, the best increase in internal friction angle (?) was 30% with the addition of 3% HDPE polymer. the internal friction angle increased by about 26.7% by adding 1% and 3% of Novolac polymer. The study concludes that adding HDPE and Novolac polymers can improve geotechnical properties, but their effect on CBR is complex and depends on the polymer percentage added and soil moisture state.
Porous Silicon (PSi) samples with (100) orientation n-type were prepared by photo-electrochemical etching process for different variable parameters and fixed electrolyte solution HF:C2H5OH:H2O (2:3:3). Physical and optical properties of PSi would be varied with the variation of process parameters such as current density, anodization time and laser wavelengths. Two types of 50 mW diode lasers were chosen, 473 nm Blue & 532 nm green at 20 mA/cm2 & 15 min etching time to assist the iodization process. The band gap of the fabricated layer has raised up to (2.9 eV) which is more than twice its original value for the c-Si (1.12 eV). _x000D_ Exploiting the obtained gap energy values, the refractive index of porous silicon layer was calculated depending upon Vandamme empirical relation. It was observed that the porosity is modifiable through etching conditions, which in turn makes refractive index also modifiable. Thus, the calculation depended on taking certain parameters as the current density and etching time in order to compare the effect of applying the two laser wavelengths. AFM was applied to observe the homogeneity and roughness of the PSi mono-layer. The results are in a very good agreement with the range of the refractive indices of PSi and the illumination with green laser gives a better conclusion to use in solar cells as a good absorber and a bad reflector.
An investigation of thermal conductivity enhancement, melting and solidification processes of Phase Change Materials (PCMs) by using metal foams has been carried out. Two models have been used in the experiments, model I for measuring the effective thermal conductivity of metal foam embedded in paraffin wax, and model II used as a small scale thermal energy storage device with and without metal foam for investigating melting and solidification processes of the PCM under different cooling conditions (natural and forced convection). The theoretical investigation involves analytical solution of two models, the semi-infinite medium for calculating the thermal conductivity, and the thermal energy storage system TESS has been analyzed including several assumptions for determining the convective heat transfer coefficient and the factors that controlling forced convection and solidification of the PCM. The experimental results show that the thermal conductivity of wax with 10 PPI metal foam increased by (37-39) times that of pure wax. Effects of pore density (10 and 40 PPI), metal foam, and mass flow rate on solidification process have been studied and the effects of pore density and metal foam on the melting process have also been investigated. The present experimental results have been compared with the available previous studies and gave a good agreement.
Bio-cement built on microbial induced carbonate precipitation MICP, be able to consolidate the loose grains and can applied for soil reinforcement. In this study, the performing of an ureolytic Sporosarcina Pasteurii for sand stabilization was estimated. The S. Pasteurii Could effectively consolidates sand particles through urea hydrolysis and the successive production of calcite. The bio improved sands had relative great compressive strength after 60 days exposure to bacterial cells injections cycles. The compressive strength of bio stabilized sands was reliant on the utilized cell concentrations and density of urea and CaCl2. High bacteria cell masses decreased the compressive strength. The optimal density of cell, was OD600 0.5, when cost and performance were taken into account. The study shows that bio cementation of sand built on microbial induced carbonate precipitation (MICP) has ability for the reduction of sand permeability through pore clogging with precipitated carbonate.
Particles filled polymer composites started to be essential because of their wide applications in addition to reducing the cost of polymer, which is a main problem. The aim of this work is studying the insulation of particulate composites resulting from the addition of filler (glass or porcelain) waste powder to reinforced epoxy matrix. Samples with and without filler were exposed to some tests to decide the influence of the filler contents on the characteristics of epoxy. Epoxy is synthesized with filler particles having (90 micron) particle sizes as reinforcement. Composites of epoxy with varying percentage (0 to 40 weights %) of filler were prepared by using hand lay-up method. The nondestructive tests consist of thermal conductivity; ultrasonic test and water absorption test have been investigated. The composite showed an improvement in physical properties with the addition of filler according to their percentages. The result show the addition of the filler in all proportions to the epoxy increased the density of the composite, leading to the ultrasonic pulses velocity ranges between 2100 m/s and 2800 m/s. Increase glass and porcelain percentage cause increase in density which increases the acoustic impedance. While the thermal conductivity decrease with glass powder percentages in the composite increase, unlike the increase in porcelain percentage which causes an increase in thermal conductivity. The 40% percentage of glass in the epoxy had higher effect on reduce the thermal conductivity. As well as from the results the epoxy reinforced by porcelain powder would have lower water absorption than epoxy reinforced by glass powder.
The optimal spacing between elliptic tubes cooled by free convection is studied numerically. A row of isothermal elliptic tubes are installed in a fixed volume and the spacing between them is selected according to the constructal theory (Bejan's theory). In this theory the spacing between the tubes is chosen such that the heat transfer density is maximized. A finite volume method is employed to solve the governing equations; SIMPLE algorithm with collocated grid is utilized for coupling between velocity and pressure. The range of Rayleigh number is (103 ? Ra ? 105), the range of the axis ratio of the tubes is (0 ? ? ? 0.5), and the working fluid is air (Pr =0.71). The results show that the optimal spacing decreases as Rayleigh number increases for all axis ratios, and the maximum density of heat transfer increases as the Raleigh number increases for all axis ratios and the highest value occurs at axis ratio (? =0) (flat plate) while the lowest value occurs at (? =0.5) (circular tube). The results also show that the optimal spacing is unchanged with the axis ratio at constant Rayleigh number.
Surface reconstruction of silicon using lasers could be utilized to produce silicon nanostructures of various features. Electrochemical and photoelectrochemical etching processes of silicon were employed to synthesize nanostructured surface. Effects of current densities 5, 10 and 20 mA/cm2 on the surface features were examined. It is found that the surface porosity and layer thickness increase with the current density. Moreover, large surface area of 410 m2/cm3 can be achieved when laser power density 0f 0.6 W/cm2 was used during the etching process. Optimum operating conditions were found to achieve better silicon nanostructured surface features. The surface roughness can be reduced to 8.3 nm using laser beam of 650 nm irradiated the silicon surface during the photoelectrochemical etching process. The surface morphology of the nanostructured silicon surface using SEM and AFM could give rich details about the surface. Silver nanoparticles of 10 – 20 nm was embedded at the nanostructured silicon surface by LIFT process to reduce the surface resistance and maintain the large surface area. This technique enables silicon nanostructures to be efficiently used in many optoelectronic applications.
This research studies the physical and mechanical properties of mortar composed of PVC plastic waste particles used as fine aggregate replacement material. PVC particles in quantities of 5%, 10%, 15%, 20%, 25%, and 30% by volume were used for sand fraction substitution. This quantity of PVC was used to formulate seven mixes with a cement content of 525 kg/m3 and a water-to-cement ratio (w/c) of 0.45. At 7 and 28 days, the compressive and splitting tensile strengths of the mortar's mechanical characteristics were evaluated. Additionally, the physical characteristics of density and absorption were investigated. The findings demonstrated that the mechanical properties and density of mortar containing PVC powder were minimized.
In this research, we successfully obtained Ni/SiC micro-composite coatings with various contents of SiC particles of particle size(10 ?m), by using electrodeposition method from nickel watts bath in which the SiC particles suspend. The effects of the current density, temperature, and particle loading(PL) of SiC particles in the electrolyte on the morphology, texture, and vol% of SiC in deposit were investigated. The morphological and structural analysis show uniform distribution of SiC particles within the composite coatings. It was found that the depositing conditions affect the microstructure of deposited nickel and the SiC vol% in deposit. Furthermore, the vol% of SiC increases in deposit by increasing the particle loading(PL) in the bath, while decreased by increasing the current density. Also the higher values of SiC vol% were obtained at temperature (50°C).
In an original article, an addition was made to the well-known Taguchi’s methodical design literature by proposing how Poisson distribution may be incorporated into the Taguchi method for enhanced performance analysis in optimization. While the article is recent, it was found compelling enough to apply this novel concept of Poisson distribution to a growing area of maintenance research known as maintenance downtime analysis. Consequently, this paper contributes to the expanding research neighborhood through a Taguchi optimization method based on Poisson distribution related to the maintenance process optimization. A valuable method to optimize maintenance downtime was developed wherein the Poisson distribution was used to achieve the probability of maintenance downtime. An important foundation of the method is the Taguchi scheme. These elements were transformed into the factor-level design of the Poisson enhanced Taguchi scheme while the framework was tested using data from a process industry for validation. Interesting, the Taguchi's signal-to-noise quotient led to an enhanced set of limiting factors for better reliability of the system as G1H1I1J1K3. By interpretation, the following was found: downtime (204.61 mins), probability density function (0.00187), and cumulative density function (0.00776). The combination of these factors and levels will enhance maintenance downtime in the process industry as a result of their contributions. The outcome revealed the competence of the model to optimization schemes.
Cancer is a disease caused by uncontrollable cell growth and division. Surgery, chemotherapy, radiotherapy, and hormonotherapy are all cancer treatment options. In addition to noninvasive cancer ablative therapy. As an example, ultrasonic therapy, even with low-intensity pulsed ultrasound (LIPUS) or high-intensity focused ultrasound (HIFU), and Laser therapy (photo-biomodulation therapy) in low-level laser therapy (LLLT) with different wavelength ranges from ultraviolet (UV), visible and infrared (IR) that all have demonstrated different results depending on the target of treatment so previous trials therapies are being studied. This paper reviews recent studies on the in vitro treatment effect of ultrasound therapy and laser therapy on normal and cancerous cell lines with specific parameters. The effect of ultrasound results showed a decrease in cell proliferation and an increase in apoptosis in different types of cells, depending especially on sound intensity, known as Special Peak Temporal Average Intensity (ISPTA). While the laser effect is noticed on cell viability, either enhance or inhibit their viability depending upon the dose of exposure and other specific parameters like wavelength, energy density, and power density used in each treatment protocol. The previous studies conclude that each response would have a treatment method with specific parameters, even an increase or decrease in cell viability. Further studies need to be applying these methods in vivo.
The present work deals with direct diffusion bonding welding without interlayer of austenitic stainless steel type AISI 304L with Oxygen Free High Conductivity pure copper (OFHC) in vacuum atmosphere (1.5 *10-5 mbr.). The optimum bonding conditions are temperature of 650 ?C, duration time of 45 min. and the applied stress of 30 MPa, in order to secure a tight contact between the mating surfaces. The corrosion behavior of diffusion bonding joints in 3.5% Nacl is studied to evaluate the corrosion resistance of welding joints by using Potentiodynamic method. The observed microstructure of corroded specimen of optimum diffusion bonding joint shows that the corrosion current density has low value as compared with base materials used. During polarization, galvanic coupling is observed between two materials used. At passivity region, inverse polarity is occurred at 450mV. Therefore, passive stainless steel 304 L behaves as cathode respective to pure copper, the corrosion behavior of the diffusion bonding joint was mostly by copper side. The corrosion results indicate the presence of galvanic effect. The corrosion current density of copper, stainless steel 304L and bond joints condition were (3.66 µA/cm2, 1.62 µA/cm2 and 1.85µA/cm2) respectively. A SEM examination of corroded diffusion bonding joint indicates that the galvanic corrosion happened on copper side. The corrosion rate of bonding joint conditions was 0.85 mpy, which is less than 1%. This means that corrosion resistance of bond joint is more than excellent.
In our work, three internal regions of rat are exposed to four different lasers with different power density, and then studying the histology of the tissues. Together the total absorption and transmission of the tissues at certain wavelength were determined.Changing the wavelength across the absorption peak caused a significant difference in laser tissue interactions and changing the absorption coefficient, relaxation time, generated heat, and the intensity as a function of penetration depth. Furthermore, little mechanical damage could be seen in conventional histology.
In this Research Geometric network modeled for combined sewer network pipe design were establish for AL-Nahrain University site by Arc map and GIS tools which is built within a feature dataset in the geodatabase. The geometric networks consist of lines and points which refer to the pips and junctions respectively. Data were collected for manholes location, flow direction, slop and elevations. Many influencing features were used in multi criteria decision making (MCDM) vie Super decision 2.0.8 software which be selected to fix the problem and find the alternative for two sewer networks. The first sewer network (A) considered the existing one and the second was the alternative one (B) , Bentley sewer Cad V8 have the ability to work with ArcGIS program as a part of it by export data as shape file from GIS then by scenario report form program that exam the part of network and find the alternative . The purpose of this research was to use this data GIS model, and developed it in future event by predicting some function like rainfall amount or adding population increasing density represent by both student and employers. As a result using (ANP) analysis this method allow to make consideration alternative we found the network(A) need to add some routs depending in the amount of person daily consumption with the amount of rain fall Intensity for the next years., judgment based on expert advice is obtained through pair-wise comparisons. Afterwards, the corresponding matrix is established, and sanity of the comparisons is checked by super decision software. Finally Existing network (A) shows highest benefit score and efficiency in this time for steady case depends on two criteria coast and optimum flow for person consumption.
The paper focuses on the role of participatory design and its various methods—such as awareness methods, social interaction methods, as well as indirect and open methods— that involve all citizens in the process of design, implementation, and future development process. The architect's role in this process is to transform the desires and visions of the participants into a practical reality, ensuring that their needs are met to create vibrant spaces. This involves achieving specific indicators that generate vitality in these spaces, including diversity, communication opportunities, strong identity, concentrated density, accessibility, and safety, all of which enhance social interaction. The paper referred to a number of international examples in Norway and Denmark, and Arab examples in Jordan that proved the effectiveness of the participatory approach in achieving vital environments. Hence, the research problem is represented by the following questions: How does participatory design contribute to enhancing the vitality of the space? To what extent is the participatory design methodology applied to enhance vitality and help achieve a sense of belonging within the space? The paper findings emphasized the importance of participatory design in meeting the needs of the local community and in creating a vital, safe, and inclusive environment characterized by social cohesion, cooperation, ownership, belonging, and equality. This highlights the importance of encouraging the entire community to engage in the design process, which can lead to creative ideas and empower citizens. The paper recommends adopting the participatory design approach to improve the quality of life and enhance the vitality of urban spaces.
This work describes seam welding process using dissimilar ferrous metals by pulsed Nd:YAG. The main objective of this work is to achieve the best welding conditions. This imposes careful selection for the welding parameters and inevitably the well design of experiment (DOE). Sheets of ASTM A240/316L stainless steel to ASTM A570/Gr30 carbon steel all of 0.5 mm in thickness were lap welded. Different pulse energies or the related peak power, pulse duration, pulse repetition rate, and welding speeds were used. Moreover, different welding speeds were controlled by the employed manipulator. The laser beam spot diameter and the standoff distance were fixed. Experimental results are supported by the computational 2D and 3D models. In this article response surface methodology (RSM) was applied to design the experiment and obtain the best parameters through a set of mathematical models that define the weld characteristics. The results show that the best joint in term of joint strength is obtained at 31.9 J pulse energy (related to 5.5 kW peak power and 5.8 ms pulse duration), power density of 1.43×106 W/cm2, 1.5 Hz pulse repetition rate, and 0.5 mm/s welding speed.
Commercial purity iron powders were produced by using a new hydrometallurgy process. It was found that the most important factor in enhancing the purity of iron was the number of water washing process. X-ray diffraction pattern showed that the high peak purity of iron powder increased with increasing the number of water washing. The developed new methodology was based on the reaction between the aqueous ferrous sulfate and the hydrochloric acid with the presence of high purity aluminum flake. The purity of iron powders increased considerably with increasing the multi-water washing for leachate containing iron powders. The purity of iron powders was reached up to approximately 93.5%. The mean particle size distribution and apparent density for the highest value of purity are 50-100 µm and 2.85 g/cm3 respectively.
Utilization of additives can be an effective way to improve the durability and performance of HMA, making them more resistant to Moisture and deformation. Plus, they can reduce the need for maintenance and repairs, saving you time and money in the long run. In this study, CKD was used in place of limestone as a filler in the asphalt mixture in proportions of 0%, 25%, 50%, 75%, and 100%, and polymer SBS 4%by weight of asphalt. According to the findings, replacement-content CKD had the highest asphalt content. When the CKD is between 25% and 50%, Stability, Flow, and Indirect Tensile Strength are improved, while the density of the asphalt mixture decreases and the amount of air voids increases at higher ratios. While SBS leads to an increase in the hardness of the adhesives. As a consequence, the stability of the SBS-containing mixes resulted in higher values than the control and additive-containing mixtures (CKD), as well as a decrease in the number of air voids. According to the results, CKD should not constitute more than half of the filler weight in the asphalt mixture.
The toxicity of permanent implants is the main concern. The release of ions from the substrate leads to toxicity. Because of how the human body works biologically, the toxicity of corrosion compounds is a byproduct of wear and fretting debris. aimed to improve the corrosion resistance of a 316L stainless steel substrate. Bio ceramic Nano-hydroxyapatite (HA) was coated using the Electrophoretic Deposition (EPD) technique. Stainless steel has good mechanical properties and high compatibility, but it suffers from body fluid attack due to its chloride content, which can penetrate the passivation layer, resulting in the release of chromium and nickel ions. Tissues and organs are damaged by the ions and debris that are released. To address this problem, it was coated with bioceramic using the EPD method. Suspensions of various powders—hydroxyapatite, magnesium oxide, zinc oxide, and the composite—were prepared and coated by electrophoretic deposition. The coated samples were dried at room temperature to ensure a homogeneous coating structure. The zeta potential test for magnesium oxide and hydroxyapatite suspensions was positive, while zinc oxide and complex suspensions were negative. One of the important parameters for achieving electrolyte and implant balance is the open circuit potential (OCP). A substantial change towards a more noble direction (less negative) was seen in the OCP-coated (316 L) alloy, suggesting excellent thermodynamic stability. Tafel extrapolation analysis was used to obtain the corrosion potential (Ecorr) and corrosion current density (Icorr) values of composite-coated stainless steel 316L, which are generally derived from the polarization curve. The findings that are in line with the MgO, HA, and ZnO coatings show a significant decrease in corrosion current (Icorr), an increase in corrosion potential (Ecorr), and a decrease in corrosion rate from (4.386 × 10-¹ mm/y) Stainless Steel 316 L to (1.417 × 10-² mm/y) MgO Coated and (1.222 × 10-³ mm/y) (65%MgO+25%ZnO+10%HA coated).
Specimens with the structure of a face-centered cubic were produced using several sets of printing conditions. An experimental testing is conducted to carefully evaluate the microstructural analysis and compressive strength of this structure. The results include the measurement of mechanical properties, such as the peak stress. Fused deposition modeling is employed for the additive manufacturing of experimental specimens made from shape memory polymer thermoplastic polyurethane (MM-3520). We take into account the impact of printing factors on lattice structures, such as layer thickness, printing temperature, and printing speed. Analyzing the microstructure of the printed specimens exhibits that the specimens with highest printing temperature, lowest printing speed and thinner printing layer have better layers adhesion and lower porosities. All the mechanical tests are performed on specimens with the same structure and at a relatively constant density. Among the tested printing parameters, using a layer height of 0.1 mm, a printing temperature of 230 °C, and a printing speed of 20 mm/s yields the highest strength in the specimens. However, specimens printed with a layer height of 0.2 mm, a printing temperature of 220 °C, and a printing speed of 30 mm/s also exhibit good strength, albeit slightly lower than the maximum values. Additionally, when using these specific settings (0.3 mm – 210 °C – 40 mm/s), the mechanical qualities are minimized, yet the stress-strain curves exhibit characteristics similar to elastomers.
Soil’s characteristics are essential for the successful design of projects such as airports runway and flexible pavement. CBR (California Bering Ratio) is one of the significant soil characteristics for highways and airports projects. Thus, the CBR property can be used to determine the subgrade reaction of soil through correlations. Many of the soil geotechnical parameters such as compaction characteristics (Maximum Dry Density, MDD; Optimum Moisture Content, OMC), and consistency parameters (Liquid Limit, LL; Plastic Limit, PL; Plasticity Index, PI) can be in charge of changes that happen in soil CBR value. Soaked and/or non-soaked conditions of soils also affect CBR value. Hence, testing soils in a laboratory for CBR calculation is time-consuming that needs notable effort. Therefore, this study aims to generate some useful correlations for soil’s CBR with compaction and consistency parameters for 85 samples of fine-grained soils. The study trials were applied on natural soil samples of various places in Sulaimani Governorate, Northern Iraq. Statistical analysis has been carried out by using SPSS software (Version 28). Soaked CBR is counted, which is important for conditions such as rural roads that remain prone to water for few days. Based on the statistical analysis, there is a significant correlation between LL, PL, PI, MDD, and OMC with CBR as the dependent variable as a single variable equation with R2 of 0.7673, 0.5423, 0.5192, 0.6489, and 0.51, respectively. In addition, the highest value of R2 correlation was obtained between CBR value with consistency and compaction properties as a multiple regression equation with R2 of 0.82. The obtained equations for correlation purposes are successfully achieved and can be used, notably, to estimate CBR value.
Lightweight foamed concrete (LWFC) is characterized as a light in self-weight, self-compacting, self-levelling, and thermal and sound isolation. But it has low strength and low ductility which leads that the application of (LWFC) in the building construction is limited. The flowability of the fresh mix of (LWFC) was evaluated by flow test. While the hardened properties of (LWFC) include, compressive6 strength, tensile6 splitting6 strength, flexural6 strength, and 6modulus of 6elasticity. This6 study6 focuses6 on the effect of the adding of silica fume and steel fibre on the mechanical properties of (LWFC). Silica fume was added as (5%) and (10%) by the weight of cement and steel fiber (0.2%) and (0.4%) of the total volume of the mix. The density of lightweight foamed concrete was 1800±50kg/ , and cement to sand ratio was (1:1) with water cement ratio (0.28). The results indicated that adding of silica fume6 and steel6 fiber6 have great effect on the mechanical properties and improve them. The addition (10%) of silica fume and (0.4%) by volume of steel fiber was the best ratio that improves the mechanical properties of the lightweight foamed concrete (LWFC). The pozzolanic index of the (5%) and (10%) silica fume was (21.9%) and (74.76%), respectively.
A numerical study was performed of natural laminar convective heat transfer to its concentrated triangular enclosure around a horizontal circular cylinder. The air-filled enclosure kept the inner and outer cylinders at uniform temperatures. The Boussinesq density approximation to the momentum problem and the control volume approach iteratively resolved the governing equations to explain buoyancy. CFD results show that the velocity behavior increases by increasing Ra, so the stream lines becomes more sluggish and less uniform behavior and vortices gets less circulated pattern. The rotation angle ? has significant effect on vortices, at 90o gives the higher range of velocity zones of free convection with higher range. The thermal boundary layer seems to be larger in rr=0.455 as compared with rr=0.345 and decreases by increasing ?. The larger variation of isotherms and thermal boundary layer appears at lower ? because the higher heat transfer rate occurs at higher ? and becomes maximum at 90o. Eight correlations of average Nusselt number have been deduced as a function of Rayleigh number for the taken values of aspect ratio and enclosure angles of rotation and inclination.
The difference between the density of the gas core of microbubbles and the surrounding media causes the behavior of microbubbles contrast agents in an ultrasound field to be nonlinear and intricate. In addition, many factors affect the radial oscillations of these microbubbles. Some of these factors are related with the bubble structure and its shell material such as the initial radius of the bubble, shell thickness, viscosity of the shell material and its elasticity. Other factors are related with the incident acoustic wave such as the driving frequency and driving pressure amplitude. In this simulation study the effects of pressure and frequency as influential factors on the stability of the microbubble were studied in wide range (frequencies are extend from f<fr to f?3 fr, pressure extends from 0.05 to 1.5 MPa.), and analyzed using the bifurcation theory to visualize and characterize the effect of these factors on the microbubbles behavior. The study expounded theoretically that the generation the higher order of subharmonic oscillations is possible to result at high driving frequencies with low and appropriate driving pressures.
Moisture damage in terms of stripping; and aging surface in terms of raveling and abrasion are among the primary distresses that lead to the deterioration of asphalt pavement, diminishing the overall quality and functionality of road surfaces. This study investigates the impact of using low-cost and locally available waste aluminum scrape powder (WASP) with a particle size ranging from sieves No.8 to No.200. WASP exhibits a high bulk specific gravity and melting point temperature on HMA mixtures, which could also potentially enhance the density and stiffness of modified mixtures. Five quantities of additives 0.5, 1.0, 1.5, 2.0, and 2.5% have been used to enhance the mechanical-durability features. The aggregate sources of AlDoz and AlNibaa'e were chosen, and different mixtures were produced utilizing Marshall and Roller compaction methods. The study's findings indicated that WASP enhanced mechanical-durability characteristics and reduced the asphalt mixture's sensitivity to abrasion, moisture damage, and aging. The optimal amount of WASP was determined to be 1.5%. In addition, based on the influence of the aggregate source and compaction technique, it is visible that the AlNibaa'e source and roller compaction mode provide superior outcomes compared to the AlDoz aggregate source and the Marshall method.
The purpose of this research is to investigate how the fiber orientation and loading axis of a composite material affect its behavior. Consideration was given to two different fiber-to-matrix ratios in order to improve the mechanical properties. Hand lay-up samples were produced in accordance with ASTM D790 for flexural testing. On UTM, tensile and flexural tests were performed on the sample. The effect of fiber orientation modifies the composites' mechanical properties. As the fiber orientation increased, the tensile strength of the composite would reduce. This carbon/epoxy composite test demonstrates better strength than those conducted at (30, 5, 60, and 90 degrees). For flexural tests, a three-point bend at 30 degrees demonstrates excellent strength. Utilizing the three-point bend method, the flexural strength and flexural modulus have been determined. The tensile strength, young's modulus, elongation percentage, maximum load to break the composite, peak load, and flexural strength of single- and double-layered carbon fibers were compared and examined. As the number of layers increased, the adhesion between layers of epoxy and fiber carbon, and glass fiber weakened, causing a decrease in almost all mechanical properties. The fabricated 2024-T3 and epoxy glass fiber had higher fatigue strength than aramid reinforced and lower density than steel alloy utilized in aircraft manufacture.
Ultra-Wideband (UWB) technology has so many striking characteristics which includes low sensitivity to fading, superior performance, low interference, easy to penetrate in walls as well as in floor. The main motive of this work is to analyze the capability of UWB technology as various aspects and improve its performance, since the main drawback of this system is that the power spectral density of the transmitted signal is rather limited. The MIMO technology may provide a solution by increasing the received SNR for the same transmission power, but the problem in this case is the spatial correlation resulted. To solve the problem two technologies are integrated along with the UWB using Time Reverse (TR) by TR-MIMO and TR-SIMO. Among these integrations, the robust performance of the UWB is analyzed by comparing the transmission rates for a given outage probability. In the last step, the (SIMO/MIMO)-UWB and TR-(SIMO/MIMO)-UWB were compared in terms of BER values to create the way of applying the UWB in so many applications.
Quality control of riverbank roads is a vital part of the road construction and maintenance process and aims to ensure infrastructure quality, safety, and sustainability. This requires adherence to technical standards, constant auditing, and regular maintenance to maintain the condition of the roads and avoid potential problems. The first step in the quality control of roads is to test the efficiency of the subgrade soil. A geotechnical investigation of subgrade soil under river bank roads is carried out to evaluate the engineering properties of the soil and determine the soil’s ability to bear the loads resulting from vehicle movement and road traffic. This investigation includes analyzing soil samples and laboratory tests to determine soil properties and determine any improvements the soil needs to bear the loads. Soil samples were collected from Al-Kadhimiya Corniche Street. It was dried and subjected to laboratory tests, the soil in this study is classified as poorly graded sand (SP), GS 2.589, the shear strength parameters an internal friction angle of 33 degrees and cohesion of 0.5 kN/m2, and the results of the compaction test indicated that the optimal moisture content was 8.1%, with a maximum dry density was 18.24 kN/m3, CBR 26.04%, and chemical tests (SO3 0.222, pH 8.55, T.SS 0.891, CL 0.085). Software FAARFIELD was used to check pavement design, the thickness design was executed utilising a subgrade CBR value of 26.04%. The subgrade pavement thickness was determined to be 304mm in total. The results agree with the actual design of Al-Kadhimiya Corniche Street, which was recently maintained during the field investigation in 2023.
The corrosion behavior of martensite phase in Cu-Al-Be shape memory alloy with aging at 150 at time 2,4and 6 hour and quenching ice water with salt, water at room temperature and oil media study by open circuit potential, tafal polarization and cyclic polarization. The microstructure of martensite study by optical microscope and x-ray diffraction(XRD) and transformation temperature was determined by Di?erential Scanning Calorimeter (DSC).the result show aging martensite at 150 at 2 and 4 hour have high open circuit potential, low corrosion current density , high corrosion potential and pitting potential than martensite without aging.
In this work a general dynamic response of two-story building due to earthquake is investigated .A spatial case of two degree mass-spring–damper random vibration model is employed .The base excitation acceleration is represented according to the well- known_x000D_ regression model by Kanai –Tajimi in term of the power specturm density (PSD). The transfer function between the ground an the roofs are evaluated assuming transverse modes of vibration._x000D_ A case study of typical two symitrical story building manufactored from reinforced concret and steel is investigated.The vibration parameters such as effective mass and stiffiness and damping are calculated according to the ACI 318-11 code.The natural frequncies , mode shape and transfer functions are calculated and plotted.The PSD acceleration at the roofs are evaluated from which the mean and standared diviation of the random accelration are found .The drift at the walls is calculated and compared with the allowable limits recommended by IBC 2015 .It is found that the probability of the bulding to be safe is between (13.74 -7.35)% for the first story and (8.7 - 1.67) % for the second.
The purpose of this study is to reduce weight and improve the mechanical properties of aircraft wing using Hybrid materials known as fiber metal laminates (FMLs). In this study, seven layers were used to produce the FMLs that consist of aluminum alloy2024-T3 reinforced by carbon and glass fibers bonded with blend of epoxy-resole. The Carbon Glass Reinforced Aluminum Laminates (CAGRALLs) was used as FMLs. The results showed that The CAGRALLs gave good mechanical properties because of increasing in tensile strength, elongation at fracture and impact toughness except flexural strength by comparing with other FMLs using commercial epoxy. The increasing in layers led to weaken adhesion force between layers of FMLs caused decreasing almost mechanical properties. The FMLs has good mechanical properties by using carbon and glass fibers by comparing with carbon and jute fibers. The CAGRALLs have higher numbers of cycles at failure under cyclic loadings than Aramid Reinforced Aluminum Laminates (ARALLs). The CAGRALLs have lower density by comparing with aluminum alloy 2024-T3 that used in manufacturing of aircraft wing.
Expansive soil poses significant challenges for civil engineers worldwide since it seriously affects the structures built upon it. This soil has a very active group of minerals called montmorillonite, which is responsible for the significant volume change it exhibits. For a number of years, chemical additives have been utilized to stabilize soil, with various levels of success. Soil stabilization has involved the use of a variety of additives, including cement, lime, polymers, salts, and combinations of these. However, lime is very often used for expansive soil stabilization as it improves the soil's mechanical properties. The effects of adding three percentages of lime (3%, 6%, and 9%) to expansive soil to improve its engineering properties are investigated through several tests. The laboratory tests consist of standard compaction, sieve analysis, atterberg limits, hydrometer, California bearing ratio, consolidation test, swelling potential, and specific gravity. The test results displayed that the plasticity index, liquid limit, swelling potential, and maximum dry density, specific gravity decreased using (3%, 6%, and 9%) lime. In contrast, the plastic limit, and optimum moisture content increased using (3%, 6%, and 9%) lime. The California bearing ratio is increased from (12.13% to 14.65%) by adding (9% L). The swelling index and compression index are decreased from (0.070 to 0.030) and from (0.581 to 0.193) respectively by adding (9% L). The swelling percentage is reduced from (18.77% to 6.03%) by adding (9% L).
The Electrodeposition process has been used to prepare Nickel-Tungsten alloys on low carbon steel substrate by using ammonical citrate bath. The influence of deposition condition by variation of current density (0.04-0.2 A/cm2) and solution temperature (60-70 °C), on the microstructure was studied. The optical microscope and the scanning electron microscopy (SEM) were used to study the morphology of the deposit while the energy dispersive spectroscopy (EDS) was used to approximate the composition, in addition to X-Ray diffraction examination. The results show that the current efficiency has the major influence on the tungsten content in the alloys due to the formation of ternary complex which reflected into the properties of the deposit._x000D_ Keywords:
Magnesium oxide nanoparticles were deposited by laser pyrolysis process. Three types of lasers were employed CW CO2, Q-switched Nd-YAG (short pulses) and long pulses Nd-YAG lasers. The size and density of nanoparticles vary with laser energy, power, pulse duration and the scanning speed of the laser. In this method, MgO nanoparticles were deposited by a laser beam on a quartz substrate from aqueous solution of magnesium nitrate. AFM images reveal formation of small nanoparticle size of 24.5 nm with surface roughness 6.97nm by Q-switched Nd-YAG laser (10 ns) when the energy was 1J. While for CO2 laser, the smallest size was 18.8 nm at 0.4mm/s scanning speed with surface roughness 5.21nm at the same scanning speed. Moreover, long Nd-YAG pulses laser produces relatively larger average size of 37.5nm at 0.8ms pulse duration. The absorption spectra from UV-Visible spectroscopy were also conducted. The best absorption intensity was obtained at a wavelength ranging between 420-430 nm for both lasers. Finally, Thermal analysis using COMSOL Multiphysics software for the deposition process reveals that maximum temperature about 440Kfor Q-Switched Nd-YAG laser at 1J laser energy. While for RF CO2 laser, the maximum temperature obtained at 0.4mm/s scanning speed is 850K.This work provides a good knowledge for the deposition of nanoparticles using laser beams.
Recently, major part of convection heat transfer researches focus on increasing fins efficiency by increasing thermal performance for the same fin volume. Metal foam is a promising way to achieve this aim. Performance analysis has been carried out to investigate the heat transfer characteristics of copper fin foam samples. The samples have been compared with the solid metal fin heat transfer. A forced convection heat transfer had been applied to a four specimens. An electrical heater heats up the fins, which are subjected to a stream of the ambient air driven by a blower fan as heat dissipated. The heat flux had been fixed along the tests with three different air velocity used; the forced heat convection had been simulated. The pores density of copper fin foam is varied in the range of 10, 20 & 40 pores per inches (PPI). Thermal performance of copper fin foam has been evaluated in terms of average Nusselt number and thermal resistance of heat sinks. The increasing in the heat transfer rate and average Nusselt number when used metal foam has been found in the range of 36-133 % compare to solid copper. Furthermore, it has been proven that this increment reaches the maximum value for a given PPI even when raise the air velocity.
The composite opened web steel joist supported floor systems have been common for many years. It is economic and has light weight and can embed the electrical conduit, ductwork and piping, eliminating the need for these to pass under the member, consequently eliminate the height between floors. In order to study the joist strength capacity under the various conditions, it had been fabricated seven joists composed of the steel and concrete slab connected to the top chord by shear connectors (headed studs). These joist have 2820 mm length c/c of the supports and 235 mm overall depth. In the present study, six variable parameters are adopted (Studs distribution, Degree of shear connection, Degree of the web inclination, Shape of the web, Density of concrete for slab and length of the shear connector). The test results exhibited that minimum strength capacity was 160kN for light weight joist and maximum capacity was 225kN for joist of long shear connectors at failure. The results were compared by ultimate flexural model by Azmi.
Most researches have predicted soil erosion of cohesive riverbanks using linear (excess shear stress model) and non-linear (Wilson model) models based on two soil parameters (detachment coefficient, kd, and critical shear stress, ?c) of the linear model and two soil mechanistic parameters (mechanistic detachment parameter, b0, and threshold parameter, b1) of the non-linear model. The goal of this research was to quantify the soil erodibility parameters of Tigris Riverbanks on Nu’maniyah-Kut Barrage reach using linear and non-linear models through the model parameters at three different water contents: dry side, optimum side, and wet side of water contents. Soil samples were collected from three locations south of Baghdad city on Nu’maniyah-Kut Barrage reach of Tigris Riverbanks. Six soil samples acquired from these sites were laboratory tests achieved using a miniature version of Jet Erosion Test device (“mini” JET) to determine the erodibility parameters of both linear and non-linear models. Blaisdell solution (BL) and scour depth solution (SD) were applied to determine (kd and ?c) of linear model from JETs data. Physical soil characteristics; including bulk density, particle size distribution (sand%, silt%, and clay%), average particle size (D50), and angle of repose were reported for six samples acquired from the three sites. The results showed lower value of kd of toe in compared with bank side for some specific sites as observed for both BL and SD solutions of excess shear stress model especially at wet side of water content. No general pattern of ?c related to different water content were observed. The parameters (b0 and b1) of non-linear model have the same behavior of linear model parameters (kd and ?c), but with different magnitude related to different water contents, respectively.
Planning standards in most countries especially in Iraq have become old and inadequate and do not fulfill the growing needs of people in the meanwhile. Also, it does not provide solutions for the society problems since it does not came from deep and modern study of the society needs and problems. In Iraq, there is a clear neglect of the urban spaces in residential buildings. As the challenges of 21st century, climate change, pollution and health crises requires infrastructure which is capable of keeping up with people needs and capable of providing healthy life, wellbeing and economic recovery. The study explores the efficiency of urban spaces in one of the Iraqi new residential complexes which is Alamal residential complex to determine the factors that affect urban spaces in vertical residential buildings in Iraq. The evaluation of the spaces was done by using direct observation method and questionnaire method. Results revealed that the spaces in such residential complex were active and efficient but it needs more spaces to be available since vertical residential buildings have high density of people. Also, there was a good care of urban spaces that fulfill the needs of children to play and also spaces which are friendly to old people. Most participants in the questionnaire have declared that the public urban space (space 3) was the most used, most favored space since it has many activities and facilities which support social activities between people living in the residential complex.
In Urban cities, services are supported by intelligent applications and are connected to each other through ad hoc networks. Any service can be operated using a compatible of an Internet of Things (IoT) technology. This study focuses on the transportation service and finding a non-cost solution to solve the crossroads congestion that affected people time and money. The Wireless Sensor Networks (WSNs) that are planted on the roads can help in monitoring the roads situation by collecting their data and send them through wireless communication to a traffic management center. In this work two phases of time are considered for a crowded area. Low-cost components are suggested to solve the congestion at the cross roads without the need for reconstruct the roads. IoT device such as smart phone can be wirelessly connected to the Traffic Management Center (TMC), which can analyze the incoming data from WSN and send back the calculated time to the police officer to control the green light long and overcome the standard time installed for all directions. The main idea is to solve the congestion problem in real time by extending the time long of the green traffic light for the road direction with the highest vehicle density. The suggested algorithm was operated on a dataset of 6 days and for the time phase from 7:00-10:00am.
In this study, the analytic model (Azmi Model) had been considered for computation the load capacities of the composite open web steel joists and compared them with those obtained from experimental tests. The capacities of seven joists had been studied, each including one of the following variables (distribution of headed studs, connection degree of the connectors, inclination of the web, shape of the web, density of slab concrete, length of connectors).Theoretically, according to the Analytic model, the referenced joist of (45° web inclination , uniformly distributed ,over connected ,short headed studs) exhibited maximum load capacity of (18.45) ton, while the joist of (45° web inclination, uniformly distributed, under connected, short headed studs) exhibited minimum load capacity of (16.23) ton at yield point of bottom chord. Experimentally, the referenced joist exhibited maximum load capacity of (15.51) ton, while the joist of (34° web inclination, uniformly distributed, over connected, short headed studs) exhibited (12.49) ton load capacity. The load capacities values of the tested joists ranged between (67%-85%) of the predicted values according to the analytic model.
Additionally, it has been demonstrated that osseointegrated implantation offers superior proprioception and control over the prosthesis, enabling more natural movement and improved functional results. Additionally, it lowers the chance of falling and increases energy transfer efficiency, making it simpler for amputees to engage in physical activity. Furthermore, as compared to conventional socket prosthesis attachment, osseointegrated implantation has been linked to higher patient satisfaction and quality of life._x000D_ It is crucial to remember that osseointegration is a surgical operation with risks including infection and implant failure. Additionally, for effective implantation, it needs a specific amount and quality of bone, which may restrict its usage in some individuals. Furthermore, osseointegrated implantation could be more expensive than conventional socket prosthetics._x000D_ Understanding the efficacy and safety of this method requires research on complication rates and outcome metrics in patients having osseointegrated prosthesis implantation. You may acquire information on things like infection rates, implant failure, patient satisfaction, and functional results by studying original research papers. Clinical decision-making can then be improved with the use of this information._x000D_ In transfemoral amputees, osseointegration has showed promise as a powerful substitute for socket prostheses. A growing corpus of research has shown that osseointegrated implantation provides advantages in terms of increasing mobility, decreasing discomfort, and improving general quality of life. The efficiency of osseointegration for transtibial and upper extremity implants has received little attention._x000D_ Minor soft tissue infections are the most frequent consequences, although they are manageable with the right treatment and monitoring. To further reduce the risk of problems and improve the overall success of osseointegrated implantation, research and development are ongoingly focused on enhancing surgical methods and implant design._x000D_ Although osseointegration has a lot of potential, not all amputees may be good candidates for it. Considerations for osseointegrated implantation must take into consideration elements including the degree and nature of the amputation, the quality and density of the bone, and the desires of the patient.