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Go to Editorial ManagerAn experimental investigation has been performed to study the effect of combined artificially roughened (ribs) with and without single Large Eddy Break-Up Devices, on flow and heat transfer characteristic of fully developed turbulent flow in rectangular duct. The aspect ratio of rectangular duct is 10, hydraulic diameter 72.72 mm, relative roughness pitch (P/e) 10 and relative roughness height (e/Dh) 0.05. The rib was in the form of circular shape with diameter of (4mm) which was mounted on heated wall of duct at spanwise direction. The experiments have been conducted by varying airflow rate in terms of Reynolds number ranging from 3.2x104 to 6.2x104 and constant heat flux of 600W/m2. The heat transfer and friction factor of the flow for rib and combined method were compared with those of a smooth duct under similar experimental conditions. It has been found that the combined method (rib with single Large Eddy Break-Up Devices) has significant effect on the friction factor and heat transfer with decreasing in friction factor with percent(1.2) and increasing Nusselt number with (4.1). Correlations for Nusselt number and friction factor in terms of (Reynolds number and Large Eddy Break-Up Devices) parameters are found which reasonably correlate the experimental data.
The aim of this work is to investigate the effect of soil corrosion on the critical buckling load of circular columns made of 2014-T4 aluminum alloy. In this work, 24 specimens were used and buried in the soil for 120 days. The samples divided into two groups (12 columns with corrosion before shot penning (SP) and ultrasonic impact treatment (UIT), and 12 columns with corrosion after combined surface treatments (SP+UIT)). The experimental1results revealed1that the corrosion negatively1affects the mechanical properties1of the material, and the1reduction percentage (R%) for1ultimate tensile strength (UTS) and1yield strength (YS) was (1.95% and 4.57%) respectively. After combined surface treatments (SP+UIT) for the corroded columns, the ultimate1tensile strength (UTS) and yield1strength (YS) were improved with (2.42%, and 2.87%) respectively. Perry-Robertson, Rankine, and ANSYS were used to estimate the critical buckling load (Pcr) and compare it with the experimental results. Rankine and Perry's formulas have been achieved a good agreement with the experimental without and with (1.5) factor of safety respectively. While ANSYS gave satisfactory prediction with a safety factor of (2.2, and 2.7) and (1.9, and 2.7) for long and intermediate columns before and after (SP+UIP) respectively.
This research deals with the extent to which corrosion affects the behavior of buckling for 6061-T4 aluminum alloy under increasing compressive dynamic loads. Two types of columns, long, and intermediate were used.1% of the length column is the allowable lateral deflection. This is called the critical buckling of the columns. For the purpose of calculating the critical deflection, a digital dial gauge was used and set at a distance of 0.7 of column length from the fixed end condition for the column. The experimental analysis revealed that the corrosion time negatively affects the mechanical properties of materials such as the corroded specimens of 60 days (The least time to observe the corrosion of aluminum in the soil) which have approximately 2.7 % reduction in ultimate strength compared with the non-corroded specimen. Increasing the corrosion time reduces the critical load such as the maximum reduction will be 4.24% in critical buckling load for 60 days’ corrosion time. The results obtained were experimentally compared with the theoretical formulas of the Perry-Robertson and Euler-Johnson formula with the results of the ANSYS. It was found that the Perry-Robertson formula has a good agreement with the experimental results with a safety factor of 1.2, while the Euler-Johnson formula agreed with the experimental results taking a safety factor of 1.5. The ANSYS results showed a good agreement between the measured and calculated values by taking 1.1 factor of safety.
The field of mechanics concerned with studying the propagation of cracks in materials is Fracture Mechanics. Technology systems are meant to withstand the loads to which they are likely to be exposed when in use. Material imperfections arising at the time of production or use of the material are, however, unavoidable and must therefore be taken into account. A stress intensity factor is a fracture parameter that defines the part failure. This paper study’s the effect of cracks on the stresses of rectangular plates having a hole in the center. The plate was subjected to tensile pressure at the top side while maintaining the bottom side fixed. The plate had four cracks distributed around the centered hole at 45o at each side. The effect of the length of the cracks on the resulted stresses and strains was investigated. Also, the effect of the position of the crack on the resulted stresses and strains was studied. Finite element models for the different plate cases were built using ANSYS software. The results showed that increasing the crack length resulted to increase the stresses and strains. The dimension of the plate width, height and thickness were 150 mm, 300 mm and 1 mm respectively, and the crack position was investigated for different crack lengths (5, 10, 15, 20, 25 mm) however the results were not steady as it looks that the crack lengths have changed the stress distribution over the plate.
Whispering Gallery Mode Micro-Resonators (WGMRs) have received significant interest due to their great sensitivity to environmental changes, compact size, and ability to operate over a wide spectral range because their low optical losses produce high-quality factors so that they can be used in various sensing applications. This work investigates the design and implementation of cylindrical WGMRs for Refractive Index (RI) sensing for different delivery fiber diameters. Single Mode Fiber with different waist diameters (80,67.1,18) µm were used as delivery fibers. At the same time, the sensor (resonator) fiber is SMF with a diameter (125 µm). Quality factors and Free Spectral Range (FSR) were calculated and analyzed for each diameter. The quality factor for all diameters was in power of 104, which is considered good. The FSR is inversely proportional to fiber diameter. FSR values were (0.678,1.75,2.03) nm for (80,67.1,18) µm delivery fiber diameters respectively. An analyte prepared by NaCl with different refractive indices is used to investigate the RI sensor performance. Higher sensitivity is obtained from the WGMR with a smaller waist diameter, which is (-)74 nm/RIU. While for the delivery fiber diameters (80,67.1) µm were (-0.28, -9.27) nm/RIU respectively. The submitted sensor will have a good contribution in the field of chemical, biological and medical applications.
Super-hydrophobic is the tendency of a surface to spit out water droplets. Only a surface with high apparent contact angle (>1500), low contact angle hysteresis (<100), low sliding angle (<50), and strong Cassie model state stability is considered a super-hydrophobic surface. In an attempt to create highly hydrophobic synthetic surfaces suitable for a range of uses, attempts have been made to mimic the super-hydrophobicity found in natural materials (such as lotus leaves). Due to its wide range of applications including waterproof, anti-fog, anti-ice and anti-corrosion surface, the laser processing process achieved the use of process parameters which had a significant impact on the roughness factor. High roughness factor F. At constant values of p = 3 mW and ω = 10 μm, at scanning speeds of 6000 mm/s.
This paper presents a study of a nonholonomic differential drive wheeled mobile robot (WMR) of the type (BOE-Bot). In this paper, two aims are presented: the first is the study of the WMR movement on a specific trajectories to get the desired goals positions and the second is the evaluation of the kinematic performance factor of the WMR movement. The kinematic model of the robot movement in terms of the robot wheels velocity is studied by making the robot to move on the desired trajectories. The determination of the actual robot centre position in two dimensions (X) and (Y) is done by tracking the movement of a red point located above the robot by using a fixed camera attached to the ceiling. The position error between the theoretical and actual WMR position vectors is studied and calculated in global and local coordinates' frames. The values of the position error percentage ratios when the robot moved on a (S-shape) trajectory were higher than its values when the robot moved on a (straight-line) trajectory because of the existence of a gyroscopic torque resulted from the WMR circular movement around an axis perpendicular to the axis of the WMR wheels rotation. Finally, the kinematic performance factor of the WMR movement is evaluated depending on the position error in the global coordinate.
thetic socket, is due to its fiber strength and hardness, and low cost, but there are other more important things which must be considered than these specifications which are1the health1and safety. In this research fiberglass is replaced with monofilament fiber in order to be safe to on makers and users of this socket. In this paper two models of lamination manufacturing have been made and compared in terms of mechanical properties and fatigue life. The first is available and consists of: (4 perlon, 2 fiberglass and 4 perlon), The second is proposed lamination which consists of: (4 perlon, 1 cotton, 1 monofilament and 4 perlon). Simulations were conducted on the made socket made of two types of lamination by using ANSYS 14.5 to show the distribution of stresses, the amount of deformation and less safety factor for both cases. The results show an increase of 42% in the Young's modulus and a decrease in tensile stress and yield stress by 10.8% and 46% respectivel, As for the stress endurance it witnessed an increase of 140%.The simulation results show a decrease in the deformation by 40.7% and an increase in the minimum value of the safety factor of 0.323 to 1.05.
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.
Today, our cities are facing a host of challenges to accomplish the quality of life or their inhabitants. On the one hand, city planners and architects seek to preserve heritage, habits, and city peculiarities. On the other hand, it is necessary that the city is kept abreast of the rapid changes in Information and Communications Technology (ICT), Internet of Things (IoT), Artificial Intelligence (AI) and smart city concept. In Baghdad, it could be observed that there are several activities based on community initiatives, awareness campaigns, and initiatives which are self-funding from youth or funding from NGOs, and INGOs. How can we invest in such initiatives to achieve a smart city, emphasizing that the city is for the people, not a city of things? As we know that smart cities have six factors: smart (economy, governance, environment, people, mobility, and living)._x000D_ This paper assumes that smart communities are the seventh factor of smart cities factors which could play an essential role to apply the smartness in Baghdad. In this case, it will help to achieve making decisions and a feedback evaluation system will be subject to transparency, openness, vitality, and sustainability because it will stem from the community and ensure the sustainability in a smart city.
Hydraulic structures, including cascade aerators, may be acknowledged as important components in improving aeration efficiency because of the intense turbulent mixing combined with large air bubble entrapment at these structures. The main objective of the present study is to achieve maximum aeration efficiency and enhance the concentration of dissolved oxygen in the water since this is an important factor in improving water quality. The present study aims to determine the most proper geometric and dynamic parameters of a typical square-shaped stepped cascade with a total height of 120 cm, and sex steps. A tread of each step is 10 cm and a rise of each step is 20 cm, where aeration efficiency is maximized. The results of the study revealed that the maximum value of water aeration efficiency, meaning an increase in dissolved oxygen in the water using a stepped cascade aerator happened when flow rates of 15 L/min, 25 L/min, and 35 L/min with aeration efficiencies of 22%, 37%, and 42% respectively. Finally, the optimization of flow rates in aeration systems can lead to improved water quality parameters. The most important feature of the present study is the innovation of a natural method of water treatment that relies on the principle of mixing, coagulation, and flocculation by hydraulic methods, which works to reduce the costs of operation.
This paper presents a simple strut and tie model to calculate the shear strength of reinforced concrete deep beams. The proposed model assumes that the shear strength is the algebraic sum of three strength components: concrete diagonal strut, vertical stirrups, and horizontal web reinforcements. The contribution of each strength components was calibrated with the test results of 305 deep beams compiled from previous studies with wide range of geometrical and material properties. The predictions of the proposed model were compared with those of the current codes of practice (ACI-318-14 and ASHTOO 2014) and those of existing model in the literature. Comparisons revealed that the proposed model provided better predictions than other models. The mean of predicted strength to test of the proposed model, the ACI-318-14 model, the ASHTOO 2014 model were 0.98, 0.79, and 0.75, respectively. The corresponding standard deviations were 0.17, 0.28, and 0.49, respectively.
The effects of the ultrasonic peening treatment (UPT) on the rotating bending fatigue behavior and the behavior of the vibrations of alloy steel DIN 41Cr4 were studied. Hardness test, Tensile test, Constant amplitude fatigue tests, and the vibrations measurements have been carried out on the specimens. Also, the fracture surface was examined and analyzed by a Scanning Electron Microscope (SEM). The results of the investigations, e.g. stress to number of cycles to failure (S-N) curves, fatigue strength improvement factor was 7%. The decreasing percentage of maximum Fast Fourier Transform (FFT) acceleration of the ultrasonic peened condition compared to the untreated conditions was 45%.
The traditional finishing method cannot keep up with recent labor market requirements, solve the problem of increasing production, improve the surface roughness and accuracy of workpiece. While the unconventional magnetic abrasive finishing (MAF) method has shown as a promising technique that can be used to finish complicated surfaces. MAF finishes metals, alloy, ceramic, and other materials that are difficult to finish by other processes. In another word, MAF improves the quality of surfaces with low cost._x000D_ This paper focuses on optimize and study the effect of inductor and pole geometry (radius of hole, angle of core, angle of pole, radius of pole), on (surface roughness (Ra) and material removal weight (W)) and fined the optimum values that increase the efficiency of MAF method. Taguchi method employed to study the influence of geometry parameters and find the optimum values using orthogonal array L9. The results conclude that the most significant factor that effects change in surface roughness (?Ra) and material removal weight(?W) are radius of the hole (R) and angle of core (?), respectively.
The traditional electric poles in Iraq are usually made from steel materials. Such materials induced high weight, corrosion, permanent deformation caused by high wind speed, etc. The study aimed to numerically examine the strength of few poles made from different materials. The pole subjected to pressure developed by actual measured wind speed of 140 km/h. The numerical model of different materials and cross sections, an octagonal section electric pole made from composite material FRP–HDPE–FRP is suggested to replace the traditional one. The results showed high safety factor, approximately 5.51 besides the low ratio of high strength to weight as compared to steel materials. Using HDPE as reinforced material resulted in pole elastically deformed with only 0.222 mm. Therefore, it can be assumed that the suggested pole acts partially as a damper. Straight octagonal cross - section of pole promoted high reduction (74.22%) in maximum Von–Misses stress of that obtained in cylindrical three-stage pole. High reduction (5.87 times) in maximum deformation value was obtained when composite octagonal pole was used as compare to tapered pole made from steel.
In term of sustainable practices, recycling plays a crucial role, particularly in the construction industry where the disposal of old structures generates significant waste. Recycling old concrete not only reduces the need for new natural resources but also eliminate waste accumulation. Numerous research study the behaviors of recycled aggregate concretes, practically focusing on the long term behaviours. A large number of studies have demonstrated that concrete made from recycled aggregate exhibits poorer long-term characteristics in comparison to aggregate from nature concrete. The long-term behaviour can be affected by three factor which is creep, shrinkage and tension stiffening. Greater management of these variables can enhance the RAC's long-term properties. The review will specifically focus on the influence of time dependent parameters i.e., creep, shrinkage, and loss of tension stiffening with time. Furthermore, it will explore the long-term deflection predicted from code used for deflection prediction, considering three codes: ACI, EC2, and the CSA code. The purpose of this paper is to enhance the understanding of long-term deflection of recycled aggregate concrete beam and evaluate the effectiveness of various factors that impact their structural performance.
Experiments were conducted to study the effect of quenching medium carbon steel in water-based MWCNTs nanofluids at 0.05 % wt. concentration quenchant, a large cylindrical sample with 46 mm diameter and 40 mm length made from medium carbon steel used with three K-type thermocouples with a diameter of 1.5 mm inserted in three locations for sample (center of the sample, mid-point between center and surface and 1 mm from the surface). A time-temperature reading data system was used to read temperature history during cooling stage.The same experiments were simulated using ANSYS Workbench with Thermal Transient Version 19, the cooling curves at three locations for the cylindrical steel sample calculated during quenching in MWCNTs nanofluids. Quench factor analysis was used to predict the hardness results from the calculated and measured cooling curves, and these results compared with the hardness test results conducted in the significant sample from the center to the surface. The results show excellent compatibility when compared between the hardness results from cooling curves, and it also shows a good agreement with the results of the hardness test, especially at the sample surface.
In this paper, models were applied to investigate the parameters that affect membrane fouling. Osmotic pressure across the membrane, salt concentration at the surface of the membrane, solute mass transfer coefficient, effective coefficient diffusion of water, and concentration polarization factor were the main parameters that calculated in this simulation. Sodium chloride was assumed the only salt existed in the feed flux. In addition, changing the applied pressure versus increasing the salt concentration in the feed flux and their effect on the water permeation coefficient was investigated. The results confirmed that concentration polarization gives a good indication about the formation of the fouling layer at the membrane surface and consequently permeate decline.
The mixing technique was applied in this study to enhance the strength performance of the cement. The addition of 3% by weight of hydroxyapatite (HA) nanoparticles were mixed with 97% polymethyl methacrylate (PMMA) acrylic polymer, which has a nano size to serve as the matrix material. The surface roughness and continuous porosity of the bone cement were found to be slightly increased by the incorporation of nanoparticles, which enhanced bone-implant osseointegration and ingrowth. Atomic force microscopy (AFM) analysis revealed that the addition of hydroxyapatite (HAp) nanoparticles resulted in a surface roughness value (Sa) of 16.25 nm, which is similar to that of natural bone. The energy-dispersive X-ray spectroscopy (EDS) mapping results discover precentor material and uniform distribution. The Sample exhibited promising results in the antibacterial test, showing efficacy against bacteria both with and without sterilization, confirming its antibacterial properties. The mechanical tests conducted on the sample, including tensile, compression, bending and Vickers hardness tests, yielded favorable results and indicated that the sample is suitable for its intended application. In the theoretical works the design of the bone, screw, and bone plate was conducted using SolidWorks, followed by an analysis using ANSYS under both axial and bending load conditions. The theoretical analysis revealed that the safety factor was less than 1 when an axial load of 13 N was applied and a bending load of 2 N was applied, indicating that the structure may not be able to withstand these loads safely. Under both ambient and physiologically relevant conditions in the human body, HA and PMMA have demonstrated to be excellent choices for enhancing the clinical performance of bone cement. This, in turn, can lead to increased longevity of implants, decreased patient risk, and lower healthcare costs
The aim of this study was to support surgeons to decide where to place the screws in order to achieve an optimal fracture healing and to prevent implant failure after a femoral shaft fracture So this paper focus on the analysis of bone-plate construct by using Finite element Analysis (FEA), comminuted femur fractured bone fixed with Dynamic Compression Plate (DCP) 16 holes by 4.5 Cortex screws, to investigate the effects of screws configuration on the mechanical behavior of different seven model as Interfragmentary strain which is the most important factor for femur fracture healing. The results state the relationships between the Von-Mises stress, Total deformation and Interfragmentary strain with respect to the screws configuration. The study shows the regions of maximum stress from stress distribution and also founded that we can decrease the Interfragmentary strain by increasing the number of screws.
This study aims to review flow-induced vibration one of the repercussions of vibrations is caused by fluid movement. In general, the investigation of the structure of the systems affects the efficiency of the components that construct those systems. This review examined the influence of generated vibrations and internal pressure on fluid transport pipes using theoretical calculations, practical tests, and numerical analysis to identify and test the dynamic behavior of static fluid transport pipes. The experimental study considered the natural frequencies caused by the fluid pressure effect under various stability situations. The flow of all liquids, such as oil, water, gas, air, and vapors, through the pipes, was tested, and the mathematical models were correctly adjusted. All empirical, theoretical, numerical, and analytical research agrees that several approaches exist to develop, modify, and improve these metrics. However, one factor affecting rheological measurements is vibration, which was addressed as needed in the middle of the 20th century due to major discoveries that damage could be rooted in vibration. Established on the determinations, they provided mathematical models paired with pressure and velocity measurements of moving fluids and the influence of produced or uninduced vibration. This study demonstrates that additional empirical investigations, particularly more detailed analytical methodologies, are urgently required to produce better findings.
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.
This paper studies the effect of different design spectral response acceleration parameters as suggested by the uniform building code (UBC), unified facilities criteria (UFC), and Iraqi seismic code(1997) (ISC 97) on the seismic response of reinforced concrete multi-story framed building located in Baghdad city, Iraq. These parameters are: (a) spectral response accelerations Ss, at short periods, and S1 at a 1-second period in accordance with international building code (IBC), (b) seismic zone factor (Z) according to UBC, (c) Seismic hazard zoning coefficient (Z) according to ISC 97. In this paper, first, the elastic seismic responses for significant modes of vibration for chosen building under design response spectrum that obtained from the above mentioned codes are calculated, and then a comparison was made among different design spectral response acceleration parameters. The intent of this study is to review the seismic provisions of the current edition of Iraqi seismic code (1997) to determine whether it provides an equivalent level of safety to that contained in other international codes. Design base shears, lateral seismic forces, inter story drifts, response spectrum modal, effective seismic modification, floors acceleration and story shears are comparatively presented.