bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical Determination of Mechanical Properties of AL-Filled Glass/Polyester Sandwich Panel under Impact Loading
Authors: Mohammed Farag Mahel , Dawood Jamal Jalal
Published: March 2021

Taguchi method and a regression model have been developed to study the effect of AL% filler contents on the glass/polyester honeycomb sandwich panel behavior subjected to impact load. Using the standard Taguchi’s array L9, analysis of means (ANOM) including main effects of S/N ratio and experimental response, ANOVA was used to determine the optimum process parameters with its significant factor. Three parameters as controlled variables have considered: AL%, mass, and height with three levels for each of them in destructive and non-destructive tests. The results show that for deflection: the mass has the highest contribution at (58.2439%) followed by the AL% filler (21.3718%). The AL% has the highest contribution for the deformation, with a percentage of (89.1144%) followed by the height and mass with a relative contribution to each other. The regression model has a good prediction, with a perfect correlation between the output and input variables. The coefficient of determination and the correlation coefficient are 89.88 % and 0.94, respectively, for deflection, while for deformation are 81.45 % and 0.9, respectively. The average error MAPE equals 6.19 % and 12.128 % for deflection and deformation, respectively. There is a strong relationship between the variables depending on the correlation coefficient, which presents as 0.94 for deflection and 0.9 for deformation. Confirmation results show that the experimental and predicted values were close to each other.
Investigating the Pull-out Capacity of a Horizontal Plate Anchor Embedded in Sandy Soil
Authors: Ali Zaynib Sadoon , Aziz Laith Jawad
Published: March 2021

Anchor systems have been widely used recently due to its importance in increasing the stability of structures subjected to uplift forces and overturning moments. Accordingly, it is vital to investigate the parameters that might affect anchor systems’ operational performance and structural behavior. The current study investigates the characteristics and parameters that might affect the uplift capacity of a horizontal anchor plate embedded in cohesionless soil. The sample of soil was brought from Al-Najaf province (Iraq). The parameters included are; plate embedding depth, the soil’s effective dimension above the plate, and soil improvement by compaction. The model setup includes forming a steel container with dimensions (70 x 70 x 70) cm and a circular steel plate of 10 cm diameter. Three embedding depth ratios were chosen; these are 0.1, 0.2, and 0.3 of the total soil sample depth. Three effective soil diameters were chosen as percentages of the plate diameter; these are 1.0%, 1.5%, and 3%. According to the ASTM specification, several physical and chemical tests were carried out on the soil sample to determine its classification and needed engineering characteristics. The laboratory test results revealed that for both treated and untreated soil samples, the ultimate uplift capacity of the anchor plate increases with increasing the embedded depth of the anchor plate; for example, at improvement ratio (D/d=3.0), the ratio (P/Po = 1.05,1.28 and 1.6) for depth ratio (h/T=0.1,0.2, and 0.3) respectively. The values of the pull-out capacity of the anchor plate are increased with increasing the improvement area above the anchor plate; for example, at depth ratio (h/T=0.3), the values P/Po = 1.05,1.28 and 1.6 for D/d=1,1.5 and 3.0) respectively. Finally, the compaction technique can effectively improve the behavior of the anchor plate.
Natural Convection in a Square Cavity Filled with Saturated Porous Media and Partially Heated From Below
Authors: Salih Noah M , Ezzat Sarah B , Hassan Afnan A , Jasim Qusay K
Published: March 2021

This paper represents an experimental study of natural convection heat transfer in a square enclosure filled with saturated porous medium and partially heated from below. Two locations (left and middle of the enclosure) has been studied in the present work to explain heat and temperature distribution inside the enclosure. The experimental results obtained under constant heat flux within the range of (1000-10000 W/m2), and modified Rayleigh number within the range of (0 < Ram < 420). The experimental results are presented in the form of temperature distribution, Nussalt and Rayleigh number are plotted versus heat flux, and for both cases. The results were expressed as isotherms, distributions. The location of the heating element has a noticeable effect on the distribution of heat and temperature. The study indicated that the Nussalt number depends on the Rayleigh number and is directly proportional to it. Furthermore, two empirical equations were obtained for the considered study cases illustrated the correlation between the Nussalt and Rayleigh numbers.
Performance Evaluation of the Single-Stage Absorption Cooling System through Energy and Exergy Analysis
Authors: Zaidan Maki H , Khalaf Hameed J , Hashim Abdulghafor M
Published: March 2021

In this study, a single effect (H2O-LiBr) water lithium bromide absorption cooling system is presented and evaluated by energy and exergy analysis. A mathematical thermodynamic model of the absorption cooling system has been found and derived from the basic principles of the first and second laws of the thermodynamics. The important parameters of performance are focused on the coefficient of performance COP and exergy efficiency. The performance was carried out over a range of operating conditions including the effect of generator, absorber and ambient temperatures. An energy and exergy investigation of separate system components were also obtained. The main obvious effect is detected for the situation of exergy efficiency for generator and absorber. The exergy efficiency increases with the rise of absorption temperature and a reverse effect is detected when the temperature of generator increases. The performance comparison of system components has been conducted in the present study. Exergy destruction of the generator was noticed to be 42% higher than exergy destruction in the absorber of 28%, due to the mixing of lithium bromide and water at high generator temperature of about 88°C. The COP of the absorption refrigeration system differs at the range (0.6 - 0.732) and maximum value was achieved at lowest temperature of absorber. The exergy analysis shows that the destroyed exergy distribution in the components of the system depends powerfully on the temperatures of system. The increasing in the generator temperature of higher than 88°C increases the COP of the current system, and with a additional increase in the generator temperature, the COP value stays constant. The obtained results lead to the documentation of factors that may affect the exergy efficiency of the (H2O-LiBr) absorption system. It was found that the efficiency of the exergy of the system increased as a result of the increasing in the ambient temperature from (25°C to 45°C). The results show that the influence of system components condition on the total exergy loss is very significant.
A Critical Review of Recent Research of Free Vibration and Stability of Functionally Graded Materials of Sandwich Plate
Authors: Njim Emad Kadum , Al-Waily Muhannad , Bakhy Sadeq H
Published: March 2021

In the past few decades, due to the unique material properties of functionally graded materials (FGM’s), they have been used in various engineering industries. This article aims to introduce an overview of the existing literature on the area of application, stability, and free vibration analysis of FGM structures conducted by some recent research studies and to provide a comprehensive overview of the development, application, different numerical representation of materials, demonstrating procedures and arrangement technique and solution method of FGM rectangular plate. It focuses on the influence of many parameters on natural frequencies and buckling loads, such as aspect ratio, power-law index, porosity distribution throughout the thickness of the plate, and face sheet thickness. This research also involves various analyses and numerical techniques for vibration and buckling analysis of the FGM sandwich plate. Furthermore, some important notes and suggestions are put forward for future work trails in this field. It is found that there is an exceptionally restricted path to investigate the same above analysis for the FGM sandwich plate with the porous metal dependent on various parameters such as gradient index, aspect ratio, face sheet thickness, porous factor, FGM layers thickness, and the number of layers.
Simulation of the Influence of Internal Pressure on Free Vibrated Aluminum Conveying Fluid Pipe
Authors: Altai Ali Abbas W , Sadiq Ghanim Sh
Published: March 2021

High temperature and pressure conditions lead to expanding the pipelines used to transport different types of fluids. A compressive axial force arises if this expansion is prevented. The present work aims to analyze pipelines’ instability due to internal pressure influence by making a simulation using ANSYS - Mechanical APDL 2019 R3. The study presents comparisons between increasing internal pressure from (0 to 10 MPa) on some pipe parameters like a natural frequency and instability for two pined-pined pipe thicknesses, which are 0.5 and 1 mm. It is concluded that the increase in internal pressure will decrease the natural frequency and stability of the vibrated system but will increase the modal damping ratio and total deformation of the tested pipe.
Computerized Generation of Asymmetric Straight Bevel Gear
Authors: Hashim Adil Habeeb , Abdullah Mohammad Qasim
Published: March 2021

To carry out any type of analysis and study the gear drives, the primary steps include the graphical representation of the gear drive under consideration. In this study, the mathematical formulations of the tooth surface, tooth root surface, and tooth root transition surface of symmetric straight bevel gear were formulated based on the planning principle. The proposed modification has been done on the mathematical formulation of the symmetric tooth profile to consider the effect of asymmetric tooth profiles (which are characterized by different pressure angles on the loaded and unloaded sides). As a result of this study, a computer program based on the above mathematical formulation has been built to represent the final shape of symmetric and asymmetric teeth profiles of straight bevel gear for different design parameters.
Numerical Study of Improved Heat Transfer with Phase Change Material Inside Rectangular Cells using Copper Rods
Authors: Jasim Ali K , Hussein Hasan Q , Sultan Hakim S , Mohsen A M
Published: March 2021

This work presents a numerical study of improving heat transfer to PCM (paraffin wax) inside a rectangular cell using copper rods. The numerical study is conducted using an enthalpy–porosity formulation in (ANSYS/FLUENT software16). The phase replacement material used in this study is paraffin wax (RT58). This study aims at improving heat transfer and absorption within phase-changing materials. The work demonstrates the effect of the presence and number of copper rods in the cell on heat transfer and the effect of this on time required to finish the melting process, thus improving the heat storage or absorption process. It is found that using copper rods inside cell filled of PCM increases the feasibility process and decreases the time to complete the melting process in the rate of 50%. It is also found that increasing the number of rods from three to five increases the melting process in the rate of 10%. In contrast, increasing number of rods decreased the time to complete the melting process.
Numerical and Experimental Study on the Influence of Low Frequency Vibration on Strains of Single Point Incremental Forming
Authors: Nema Riham Ali , Tawfik Mauwafak Ali , Sadoon Muthanna Hamzah
Published: March 2021

Single point incremental forming (SPIF) is a decent potential procedure appropriate for small batch production. In addition to that, the formability of the material is expanded compared to the other sheet metal forming processes. Meanwhile, the more advanced SPIF process requires perfect comprehension of the material deformation technique. In this paper, the equipment of vibration - sheet metal forming was designed. Finite element model was used to demonstrate and analyze the effect of different frequencies of vibration on the strain distribution in single point incremental forming process. The results show that specific vibration parameters can decrease strain. Moreover, an experimental vibration system using single point incremental forming was designed. The numerical model is primarily supported by test results conclusions from a simple cone of Al1050 aluminum alloy.
Characteristics and Management of Produced Water in Al-Ahdab Oil Field
Authors: Mahbouba Zahraa N , Abdulkhalik Mahmood K , Mussa Jassim H
Published: March 2021

Produced water (PW) is the wastewater generated when water from the underground reservoir is brought to the surface during oil or gas extraction. PW is generated in large amounts and has a complex composition, containing various toxic organic and inorganic compounds. Thus, it is a big issue for water and environmental pollution; therefore, it must be treated to meet the requirement of injection, disposal or re-use. This paper attempts to summarize the characteristics of produced water and clarifying the current treatment operations in Al-Ahdab oil field located between Numania and Al-Kut (the center of Kut Province), about 180 km to the south-east of Baghdad/Iraq. This field is managed by Iraqi Middle Oil Company. The collected samples of the PW from Al-Ahdab oil field were taken and analysed for pre-treatment and post-treatment. The treatment units consists of de-oiling (removal of dispersed oil and grease), desalination, removal of suspended particles and sand, removal of soluble organics, removal of dissolved gases and removal of naturally occurring radioactive materials (NORM). The result showed that the current treatment does not meet the requirements for irrigation water quality or other benefits used. At the same time, it suitable for re-injection operation into a reservoir for oil extraction purposes.
Equivalent Distribution of Natural and Artificial Lighting in the Interior Space
Authors: Ameen Abdulsalam A M , Abdulhussein Ruaa Saad , Suhair Hussein A Y
Published: March 2021

In this research, the classrooms of the College of Applied Arts in Baghdad were chosen as a model for studying the levels of illumination and the extent of their homogeneity in all points of space for four similar classrooms in terms of design. The readings obtained by measuring devices were compared with the required standards, where a large deviation of these readings was observed with general criteria due to the rotation of earth around itself. This leads to a change in the angle of sunlight falling on the windows of the interior space in one day for the period during which students were in these halls. Although natural lighting is important, by obtaining the ideal display factor of (1), it may be impossible to obtain this value by using artificial lighting in addition to the health and economic aspects. Therefore, the researchers suggested an electrical system consisting of sensors of the intensity of illumination distributed on multiple points regularly within the area. The internal space is linked to an electronic self-control panel, in a way that achieves a level of illumination and uniformity close to the required standards. This electrical circuit controls the automatic closing and opening of window blinds, which are made of metal strips or any other material chosen by the interior designer so that they move horizontally and vertically and change automatically in conjunction with the change of the angle of sunlight falling on the windows of the interior space. Each curtain is divided into parts and every part moves vertically and horizontally separately from the other part to cover a specific area of space in order to achieve the best state of homogeneity, with a level of illumination close to the general standards and for the total area of the internal space.
Studying the Effect of Head Difference on Exit Gradients and Uplift Pressures Beneath Hydraulic Structures by Gene Expression Programming
Authors: Khashan Duaa Hadi , Hassan Waqed H
Published: March 2021

The seeping flow under the hydraulic structure produces uplifting pressure on its floor, which affects the performance of these structures. This problem was numerically analyzed using the finite difference method in Matlab after verification with GeoStudio software. This study’s main objective is to investigate the effects of head difference variation, the cutoffs’ locations, and depths on the exit gradient and uplift pressure. An empirical equation has been developed to predict the exit gradient by employing gene expression programming (GEP). More than 975 runs were executed using finite difference code with differential (H=5,10,15m), were studied over isotropic soil foundation. The results indicate that the differential head ratio (H/B) had a considerable effect on increasing the exit gradient and uplift pressure, mainly when the value of the differential head ratio (H/B =3/3) and minimum exit gradient was observed when the cutoff location ratio at the downstream is of (x1/b=1) with a maximum relative depth of (d1/b=0.6), while the minimum uplift pressure was observed when the cutoff location ratio at the upstream is of (x1/B=0) with a minimum relative depth of (d1/B=0.1). The results also indicate that the maximum exit gradient is observed when the ratio of the length of upstream cutoff to the length of downstream cutoff is (d1/d2 = 1). Based on the simulation results, the equation obtained using the Genetic expression programming (GEP) model performed better predicting to exit gradient for one cutoff with a coefficient of determination R2 equals 0.954 for training and 0.957 for testing and two cutoffs with R2 equals 0.93 for training and 0.94 for testing.
Effect of Curvature on the Dynamic Response of Composite Steel I-Girder Bridges
Authors: Qassim Huda J , Ali Anis A Mohamad
Published: March 2021

Elaborated three-dimensional finite element models are generated to study the effect of the radius of curvature on the free vibration and dynamic response of the composite steel I-girder bridges. The bridge is modelled by using ANSYS 15.0 program with solid and shell elements to represent concrete and steel members, respectively. AASHTO LRFD HL-93 truck is idealized as 3D model consisting of five lumped masses connected by rigid beams and supported by spring-dampers. The profiles of road surface roughness are generated by MATLAB developed program depend on the power spectral density (PSD). The models used are capable to take all bridge and vehicle characteristics into consideration. The dynamic responses of the horizontally curved bridge are investigated under conditions of various vehicular loading positions. The dynamic behaviour is presented in terms of Impact Factors (IM). The results show that the bridge natural frequencies are significantly affected by the radius of curvature. The relationship between the IM and the radius of curvature is governed by the position of vehicle on transverse sections of the bridge. AASHTO LRFD specification tends to underestimate the values of IM.
Hybrid ANOVA and LASSO Methods for Feature Selection and Linear Support Vector, Multilayer Perceptron and Random Forest Classifiers Based on Spark Environment for Microarray Data Classification
Authors: Albaldawi Wafaa S , Almuttairi Rafah M
Published: March 2021

Microarray dataset frequently contains a countless number of insignificant and irrelevant genes that might lead to loss of valuable data. The classes with both high importance and high significance gene sets are commonly preferred for selecting the genes, which determines the sample classification into their particular classes. This property has obtained a lot of importance among the specialists and experts in microarray dataset classification. The trained classifier model is tested for cancer datasets and Huntington disease data (HD) which consists of Prostate cancer (Singh) dataset comprising 102 samples, 52 of which are tumors and 50 are normal with 12625 genes. The lung cancer (Gordon) dataset comprises 181 samples, 150 of which are normal and 31 are tumors with 12533 genes. The breast cancer (Chin) dataset comprises 118 samples, 43 of which are normal and 75 are tumors with 22215 genes. The breast cancer (Chowdary) dataset comprises 104 samples, 62 of which are normal and 42 are tumors with 22283 genes. Finally, the Huntington disease (Borovecki) dataset comprises 31 samples, 14 of which are normal and 17 are with Huntington’s disease with 22283 genes. This paper uses Multilayer Perceptron Classifier (MLP), Random Forest (RF) and Linear Support Vector classifier (LSVC) classification algorithms with six different feature selection methods named as Principal Component Analysis (PCA), Extra Tree Classifier (ETC), Analysis of Variance (ANOVA), Least Absolute Shrinkage and Selection Operator (LASSO), Chi-Square and Random Forest Regressor (RFR). Further, the paper presents a comparative analysis on the obtained classification accuracy and time consumed among the models in Spark environment and in conventional system. Performance parameters such as accuracy and time consumed are applied in this comparative analysis to analyze the behavior of the classifiers in the two environments. Th results indicate that the models in spark environment was extremely effective for processing large-dimension data, which cannot be processed with conventional implementation related to a some algorithms. After that, a proposed hybrid model containing embedded approach (LASSO) and the Filter (ANOVA) approach was used to select the optimized features form the high dimensional dataset. With the reduced dimension of features, classification is performed on the reduced data set to classify the samples into normal or abnormal and applied in spark in hadoop cluster (distributed manner). The proposed model achieved accuracy of 100% in case of Borovecki dataset when using all classifiers, 100% in case of Singh, Chowdary and Gordon datasets when classified with RF and LSVC classifiers. Also, accuracy was 96% in case of Chin dataset when using RF classifier with optimal genes with respect to accuracy and time consumed.
Behavior of Foundation Rested on Geogrid-Reinforced Soil : A Review
Authors: Jawad Zahraa H , Shakir Ressol R
Published: March 2021

In many cases, the soil in Nasseriyah, Iraq, is not suitable to support the shallow foundations of low to medium rise buildings without improvement or replacing the founded layer with a strong layer. Therefore, the reinforcement method as one of many types of improvement methods may be used to increase the bearing capacity and reduce the settlement when the replacement soil is not enough to support the foundation. This paper reviews the most important reinforcement materials such as geogrid that may be used to increase the strength of the soil and other details of the number of layers, the distance between layers and the optimum location of the top reinforced layer for clay and sand soil. Experimental studies and theoretical modelling performed through the last decades are reviewed to choose the best arrangement of geogrid material that gives the best performance when it is used with soil. It is found that the geogrid can be used to increase the bearing capacity, however, the studies on clay reinforced with geogrid compared to sand soil are few. Since the researches on the behavior of foundation resting on clay reinforced with geogrid are few and because the soil in Nasseriyah is mostly clay soil, it is recommended to study the behavior of foundation resting on clay reinforced soil.
Modal Analysis of Fixed - Free Beam Considering Different Geometric Parameters and Materials
Authors: Flaieh Enass H , Dwech Abbas Aziz , Mosheer Mohammed Refaat
Published: March 2021

The early studying of natural frequencies and associated mode shapes for different geometric parameters and different boundary conditions is considered an integral approach that has received great attention in industrial applications to prevent catastrophic failure in machines. The effect of different diameters (Solid and Hollow) on the transverse bending and torsional natural frequencies on a uniform steel beam with a circular cross-section is studied. The effect of different materials and different beam lengths on the fundamental transverse bending and torsional natural frequencies are introduced for Fixed-Free supported beam. Theoretical analysis calculation and the Finite Element Methods using ANSYS Workbench 17 software results are introduced. Theoretical and numerical methods give approximately the same results. Figures of effects of the beam length, material types, and different inner diameters on the transverse bending, and torsional natural frequencies of the uniform beam are performed.
Experimental Investigation and Parametric Optimization of FSW for the 2024-O Aluminum Alloy Joints
Authors: Takhakh A M , Hussein H K
Published: March 2021

The effect of welding parameters on mechanical properties of aluminum alloy AA 2024-O Friction stir-welded (FSW) joints was investigated in the present study. Taguchi method was used to evaluate the optimum value of process parameters from tensile tests using nine experiments designed according to the matrix proposed by the scientist Taguchi for the design of experiments (L9) using two parameters (welding speed and rotation speed). Two different process parameters have been selected: rotational speeds of 1300,1500 and 1700 rpm and feed speeds of 20,40 and 60 mm/min. The design of experiments (DOE) is performed by L9 (3Λ2) orthogonal array (9 experiments, two variables, three levels). Also, the signal–to–noise (S/N) ratio larger is better has been performed for analyzing the results σu for FSW &FSP) by the statistical software (MINITABTM ® 16). The best results of the weld gained at the parameter 40 mm/min travel speed and 1300 rpm rotation speed. The efficiency obtained was 95% respect to the ultimate tensile strength (UTS) of the base metal. In addition, the analysis of variance (ANOVA) techniques has also been performed by the statistical software (DOE Pro XL) to identify the essential factors that are affecting the ultimate tensile strength (UTS) for FSW.
Influence of Additive Alumina Nanopowder on Surface Roughness During WEDM Process
Authors: Abed Farook Nehad , sapit Azwan bin , Shather Saad Kariem
Published: March 2021

The present paper focuses on the wire electrical discharge machining (WEDM) of titanium alloys. It can be considered as an attempt to develop two dielectrics in the WEDM significantly affects the efficiency of machining. This paper explores surface ruggedness during the processing of titanium of various dielectric fluids, including demineralized water and dielectric alumina. The findings show that dielectric alumina as a dielectric produces decreased ruggedness on the surface. Also, surface rudeness is better for demineralized water as the dielectric powder is mixed with non-conductive alumina powder. Many dielectric liquids show that surface ruggedness decreases. Alumina powder and ethylene glycol to dielectric water. A comparative surface roughness analysis for different dielectric fluids was also performed. Using surface roughness to analyze surface roughness is further studied. Conducting a further investigation to use the response surface method (RSM) on surface integrity in each type of the dielectric with the help of better. Hence, WEDM is performed on Ti-6242 to use the designer expert 10 to analysis ANOVA RSM titanium and varying dielectric fluids. From the findings, it is noted that combining non-conductive alumina powder and demineralized water has a significant impact, which decreased of WEDM machined surface of Ti-6242.
Enhancement Tensile Strength, Creep Resistance and Hardness of an Epoxy Resin by Adding SiO2 Nanoparticles
Authors: Al-Shawi Safaa A , Alansari Luay S , Diwan Abbas Ali , Alkhatat Aseel
Published: March 2021

Improving the mechanical properties of polymeric materials has become necessary for the mechanical designer, especially by using nano materials due to easy and wide use. Therefore, in this research, silica nanoparticles (SiO2NPs) were used to improve the tensile, creep resistance, and hardness of epoxy. The volumetric ratios of SiO2NPs (0.5, 1, 1.5, and 2%) were mixed by using a magnetic starrier and ultrasound mixer then poured into a mold. The tensile, creep resistance, and hardness properties of the resulting composites were studied. The microstructure was investigated using a field emission scanning electron microscope (FESEM) and x-ray diffraction devices. The results showed that the best Young Modules and the ultimate stress were obtained at (1.5%) of SiO2NPs, while the best creep strain improvement was at (1%) of SiO2NPs. The SEM and X-ray diffraction results showed homogeneous silica nanostructures.
Design and Manufacturing of New Low (Weight and Cost) 3D Printed Pylon Prosthesis for Amputee
Authors: Tahir Muhammad Safa Al-Din , Kadhim Fahad M
Published: March 2021

The standard traditional prosthetic pylon is manufactured from stainless steel, titanium, Aluminium alloys due to their lightweights. Despite the low weight of pylon made of these alloys, the pylon is characterized by its high costs. In this study, a new prosthetic pylon is designed and manufactured from PLA carbon fiber material to produce a pylon characteristic with a lighter weight and cheaper than the standard pylon with its ability to bear the patient’s weight without any mechanical failure. The mechanical properties (yield stress, ultimate stress, and endurance stress) of the PLA carbon fiber filament were measured. The finite element method analysis of the pylon was done by using the ANSYS-14.5 program. The experimental and numerical results showed that the weight of the new prosthetic pylon is less than the weights of Stainless steel, Titanium, and Aluminium pylon by 60%,42%, and 50%, respectively, and the cost of the new prosthetic pylon is cheaper than the Stainless steel, Titanium, and Aluminium pylon by 97.5%,98%, and 96%, respectively. The mechanical properties of printed pylon material are the modulus of elasticity equal to 1.38GPa, the yield stress is 33.5MPa, the ultimate stress is 49.14 MPa, and the endurance stress is 19.16 MPa. The results also showed that the pylon’s buckling stress is higher than the yield stress and von mises stress is less than the yield stress; this proves the successful design of the pylon. The new design is cheaper, lighter, and can withstand higher patient weights.
Structural Properties of Porous Silicon Carbide Bonded with Bentonite, Prepared by a Gas-Emitting Chemical Reaction Method
Authors: Shalal Lara A , Zaidan Shihab A
Published: March 2021

Direct foaming and bonding techniques were used to fabricate porous silicon carbide ceramics. Silicon carbide is characterized by a high melting temperature; it is always referred to as being bonded with low melting point materials such as bentonite. The technique of generating gases from the reaction of hydrochloric acid HCl with aluminum was used in silicon carbide-bentonite suspension, and by means of which high porosity bodies were prepared by adding different bentonite (10,15,20 and 25 wt.%). After molding them, it is dried and fired at 1100°C. The results of the X-ray diffraction analysis was founded that the main phases appearing after the firing process are α and β–SiC with quartz and mullite, where a part of (β–SiC) is transformed to (α-SiC) and transformation a part of Quartz to Tridymite, which means an increase in the stability of the crystalline phases. The porosity of specimens was decreased with bentonite increases after the firing process, and the values ranged between 62.3% and 72.3%. The compressive strength was increased with bentonite additions increases in the range from 4.35 MPa to 5.08 MPa. From the above results, it is clear that this type of porous (SiC-bentonite) composites can be used in fluid filtration with high efficiency, especially at high temperatures.
Optimization of Electroless Ni-P, Ni-Cu-P and Ni-Cu-P-TiO2 Nanocomposite Coatings Microhardness using Taguchi Method
Authors: Ali Sama Z. , Abbas Laith K. , Hussein Abbas Kh.
Published: March 2021

This paper studies the electroless (Ni-P) deposition which is used in different engineering applications due to their ability to modify and enhance the surface properties of the steel substrate. The electroless plating process was used to prepare (Ni-Cu-P), (Ni-P) and (Ni-Cu-P/Nano TiO2) alloys in this research. Deposition process parameters based on (L28) Taguchi orthogonal configuration with three process parameters, viz., stirring speed, temperature, time, are designed for optimum microhardness. Under the Taguchi series, the microhardness activity of electroless (Ni-P-TiO2) nanocomposite deposition was measured. The findings revealed that the integration of TiO2 into the coating allows micro-hardness cause an increase. Finally, optimum conditions were achieved as A2B1C2 (i.e. Speed of stirring = 1000 r.p.m, Temperature = 90 °C and Time = 70 min).
Characterization and Buckling Investigation of Composite Materials to be used in the Prosthetic Pylon Manufacturing
Authors: Abdalikhwa Hayder Zaher , Al-Shammari Mohsin Abdullah , Hussein Emad Qasem
Published: March 2021

A prosthetic pylon is a part of an artificial lower limb, which is a very interesting area of biomedical engineering today. The research aims to show the hung innovations and developments of new suggested composite material, to modify the prosthetic pylon (which is generally made of lightweight metal such as aluminum, titanium, stainless steel, or an alloy of these), extends its life and increase the comfort of its user. Vacuum bagging technique was used to manufacture the samples which consist of constant perlon layers and a different number of composite material (Carbon or Glass) fiber layers as reinforcement materials at (0°/90°) orientation relative to the applied load and polymethyl methacrylate (PMMA) as a resin. The work included two major parts; theoretical and experimental tests for the real case. The theoretical and experimental results showed that the modulus of elasticity, tensile strength, and critical buckling load increase with the increasing the number of composite fiber layers. The percentage of increase in modulus of elasticity, tensile strength and critical buckling load for the specimen with three carbon layers and perlon layers in PMMA matrix was compared with three glass layers and perlon layers in PMMA matrix specimen and it was (12.5%, 5% & 17%) respectively, at (0°/90°) fibers orientation relative to the applied force. Validation of the results is conducted by comparing with results in other literature, a good agreement between them was found.
Flexural Properties of Functionally Graded Silica Nanoparticles
Authors: Shareef Mahdi M S , Al-Khazraji Ahmed Naif , Amin Samir Ali
Published: March 2021

In the present research, layered-functionally graded polymer nanocomposites were made via the silica (SiO2) nanoparticles (14-36 nm in diameter) distributed in the epoxy matrix throughout the ultra-sonication by hand lay–up technique. The change in volume fraction (Vf.) of the nanoparticles was given in the direction of thickness to reach the gradation. Layers having a thickness of (1.2 mm) with different nanoparticles concentrations were consecutively casted in acrylic molds to fabricate the graded composite sheet having a thickness of (6 mm). To fabricate the functionally graded layers, different concentrations of nanoparticles were taken (0, 0.5, 1, 1.5, 2 and 2.5 %Vf) and tested by tensile test. The improvement in the properties of composite samples included the all ratios up to 2% Vf. of the adding filler, and the properties were then decreased. The mechanical property that was studied was the flexural resistance. Flexural properties of three types of FGMs (FGM1, FGM2 and FGM3), isotropic nanocomposite (1% SiO2) and pristine epoxy in order to evaluate their mechanical property, such as Stress–Strain criteria and flexural Young’s modulus, were obtained by 3-point bending test, with loading from pure and composite side for FGM1 and at one side of FGM2 and FGM3 isotropic nanocomposite (1% SiO2) and pristine epoxy. The results manifested that the flexural strength and Young’s modulus loaded from the pure epoxy side was higher than when samples loaded from the composites side for FGM1. The mechanical properties of the epoxy resin and nanocomposites (tensile and compression) and the density for each layer were determined and could be useful for the finite element analysis of the 3-point bending test for FGMs specimens by using Design Modeler (ANSYS Workbench). Experimental results were validated by developing a detailed three-dimensional finite element model. Results of the progressive deformation from the finite element model agreed well with the experimental results.
A review on cutting fluids used in machining processes
Authors: Singh Jasjeevan , Gill Simranpreet Singh , Dogra Manu , Singh Rupinder
Published: March 2021

Cutting fluids provide cooling at the cutting tool and on the surface of work piece, lubricate the tool-workpiece interface and evacuate chips from the cutting zone in the machining processes. The primary reason for using cutting fluid is to reduce the temperature at cutting zone and friction wear either through cooling or lubrication. To maximize the efficiency of cutting fluids in machining processes the knowledge of machining conditions and cutting fluid types are critically important. However, misemploy of the cutting fluid and non efficient method of disposal can raise health issues and environmental impact. In this paper, an attempt has been made to provide overview of cutting fluids type, cooling techniques and main alternatives as dry machining, cryogenic cooling, minimum quantity lubrication and hybrid cooling minimizing use of cutting fluids. The inclusion of solid lubricants, nano fluids in lubrication/cooling techniques results in increase in the productivity of the process due to reduction in friction and heat at the cutting zone. The cutting parameters and type of tools utilized by various researchers have been summed up and introduced in this paper to provide useful information to various researcher works.
Ultrasonic standing wave chamber for engineering microstructures of water- and lipid-based materials
Authors: Valoppi Fabio , Salmi Ari , Ratilainen Miika , Puranen Tuomas , Tommiska Oskari , Hyvönen Jere , Heikkilä Jesse , Haeggström Edward
Published: March 2021

Ability to control the structure of water- and lipid-based materials is important when tailoring their mechanical, thermal, and sensory properties in e.g. food, cosmetic, pharmaceutical, and chemical applications. We present an approach for organizing solid particle dispersions and lipid crystals during their formation using ultrasonic standing waves (US-SW). We designed and built a chamber to apply US-SW to water- and lipid-based samples, control their cooling rates, and observe the processes in real time using optical microscopy. As an example, we demonstrated that this process is applicable during the crystallization of saturated fat, the formation of oleogels, and sucrose crystals dispersions. The results indicate ability to control crystalline microstructures in static and dynamic temperature conditions.
Carry on caring: infected females maintain their parental care despite high mortality
Authors: Ratz Tom , Monteith Katy M , Vale Pedro F , Smiseth Per T
Published: March 2021

Parental care is a key component of an organism’s reproductive strategy that is thought to trade-off with allocation toward immunity. Yet, it is unclear how caring parents respond to pathogens: do infected parents reduce care as a sickness behavior or simply from being ill or do they prioritize their offspring by maintaining high levels of care? To address this issue, we investigated the consequences of infection by the pathogen Serratia marcescens on mortality, time spent providing care, reproductive output, and expression of immune genes of female parents in the burying beetle Nicrophorus vespilloides. We compared untreated control females with infected females that were inoculated with live bacteria, immune-challenged females that were inoculated with heat-killed bacteria, and injured females that were injected with buffer. We found that infected and immune-challenged females changed their immune gene expression and that infected females suffered increased mortality. Nevertheless, infected and immune-challenged females maintained their normal level of care and reproductive output. There was thus no evidence that infection led to either a decrease or an increase in parental care or reproductive output. Our results show that parental care, which is generally highly flexible, can remain remarkably robust and consistent despite the elevated mortality caused by infection by pathogens. Overall, these findings suggest that infected females maintain a high level of parental care, a strategy that may ensure that offspring receive the necessary amount of care but that might be detrimental to the parents’ own survival or that may even facilitate disease transmission to offspring.
Proximal aortic aneurysms: correlation of maximum aortic diameter and aortic wall thickness
Authors: Haunschild Josephina , Barnard Sarah Jane , Misfeld Martin , Saeed Diyar , Davierwala Piroze , Leontyev Sergey , Mende Meinhard , Borger Michael A , Etz Christian D
Published: March 2021

OBJECTIVES

The goal of therapy of proximal aortic aneurysms is to prevent an aortic catastrophe, e.g. acute dissection or rupture. The decision to intervene is currently based on maximum aortic diameter complemented by known risk factors like bicuspid aortic valve, positive family history or rapid growth rate. When applying Laplace’s law, wall tension is determined by pressure × radius divided by aortic wall thickness. Because current imaging modalities lack precision, wall thickness is currently neglected. The purpose of our study was therefore to correlate maximum aortic diameter with aortic wall thickness and known indices for adverse aortic events.

METHODS

Aortic samples from 292 patients were collected during cardiac surgery, of whom 158 presented with a bicuspid aortic valve and 134, with a tricuspid aortic valve. Aortic specimens were obtained during the operation and stored in 4% formaldehyde. Histological staining and analysis were performed to determine the thickness of the aortic wall.

RESULTS

Patients were 62 ± 13 years old at the time of the operation; 77% were men. The mean aortic dimensions were 44 mm, 41 mm and 51 mm at the aortic root, sinotubular junction and ascending aorta, respectively. Aortic valve stenosis was the most frequent (49%) valvular dysfunction, followed by aortic valve regurgitation (33%) and combined dysfunction (10%). The maximum aortic diameter at the ascending level did not correlate with the thickness of the media (R = 0.07) or the intima (R = 0.28) at the convex sample site. There was also no correlation of the ascending aortic diameter with age (R = −0.18) or body surface area (R = 0.07). The thickness of the intima (r = 0.31) and the media (R = 0.035) did not correlate with the Svensson index of aortic risk. Similarly, there was a low (R = 0.29) or absent (R = −0.04) correlation between the aortic size index and the intima or media thickness, respectively. There was a similar relationship of median thickness of the intima in the 4 aortic height index risk categories (P < 0.001).

CONCLUSIONS

Aortic diameter and conventional indices of aortic risk do not correlate with aortic wall thickness. Other indices may be required in order to identify patients at high risk for aortic complications.
Assessing the incidence of catastrophic health expenditure and impoverishment from out-of-pocket payments and their determinants in Bangladesh: evidence from the nationwide Household Income and Expenditure Survey 2016
Authors: Ahmed Sayem , Ahmed Mohammad Wahid , Hasan Md Zahid , Mehdi Gazi Golam , Islam Ziaul , Rehnberg Clas , Niessen Louis W , Khan Jahangir A M
Published: March 2021

Background

Out-of-pocket (OOP) payments for healthcare have been increasing steadily in Bangladesh, which deteriorates the financial risk protection of many households.

Methods

We aimed to investigate the incidence of catastrophic health expenditure (CHE) and impoverishment from OOP payments and their determinants. We employed nationally representative Household Income and Expenditure Survey 2016 data with a sample of 46 076 households. A household that made OOP payments of >10% of its total or 40% of its non-food expenditure was considered to be facing CHE. We estimated the impoverishment using both national and international poverty lines. Multiple logistic models were employed to identify the determinants of CHE and impoverishment.

Results

The incidence of CHE was estimated as 24.6% and 10.9% using 10% of the total and 40% of non-food expenditure as thresholds, respectively, and these were concentrated among the poor. About 4.5% of the population (8.61 million) fell into poverty during 2016. Utilization of private facilities, the presence of older people, chronic illness and geographical location were the main determinants of both CHE and impoverishment.

Conclusion

The financial hardship due to OOP payments was high and it should be reduced by regulating the private health sector and covering the care of older people and chronic illness by prepayment-financing mechanisms.
Policy School Deans Want It All: Results of a Survey of APSIA Deans and Top-50 Political Science Department Chairs on Hiring and Promotion
Authors: Desch Michael C , Goldgeier James , Petrova Ana K , Peh Kimberly
Published: March 2021

How do intellectual leaders of professional schools of international affairs, whose institutions primarily educate and train master's students for careers in government, the non-governmental sector, and the private sector, differ from academic administrators in disciplinary departments, whose primary raison d’être is producing the next generation of scholars whose primary task is to conduct basic research, in terms of how they see the academic enterprise and their expectations of faculty research and writing? The results of our recent survey of deans of the Association of Professional Schools of International Affairs (APSIA), the leading professional body for international relations-oriented policy schools, and chairs of Top-50 political science departments, reveal some predictable differences but also some surprising overlap. Specifically, we find a clear convergence between disciplinary departments and APSIA schools on the core requirements for promotion and tenure: Peer-reviewed publications in high-impact scholarly journals and leading university presses. But rather than relax demands for other activities by their faculty as they hold them to the expectations of their disciplines, APSIA deans still expect significant policy and broader public engagement from them. In other words, policy schools’ faculties face a greater array of professional demands than their disciplinary colleagues. APSIA schools simultaneously embrace the disciplinary criteria for excellence and still try to maintain a close policy focus as they seek to bridge the gap between these two worlds. How feasible this effort will turn out to be hinges on whether policy school faculty can indeed do it all.