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This work studied in detail for the first time the bending of laminated composite plates subjected t mechanical variations by new theory Trigonometric and Trigonometric-Hyperbolic functions of shear deformation. From the Euler-Lagrange hypothesis and the equations of the shear deformation theory, we will develop a present method. One of the most important problems of composite plates is the analysis of their bending behavior. The correct approach used to study their bending behavior includes two trigonometric and trigonometric-hyperbolic functions satisfying the null shear stress condition at the free edges. In this paper the bending problem is solved analytically by developing a computational code and numerically solved by Finite Element Method. In order to simplify the study of the bending behavior, an approach taking into consideration the effect of the transverse shear deformation without the shear coefficient of correction with only four unknowns has been developed while requiring five or more unknowns for other theories. Convergence analysis has been carried and the results are compared to open literature available for plate bending analysis. The approach proves to be simple and useful in analyzing the bending behavior of composite layered plates. [ABSTRACT FROM AUTHOR]

In the engineering approach, the calculation of stress-strain values is crucial for determining the mechanical properties of materials. It is known that stress values could be calculated using the cross-section area, the moment of inertia of the material, and even strain values. However, the experimental determination of strain values is somewhat more complicated. In strain calculation, a video- extensometer and strain gauge are generally utilized. The goal of this study is to determine the strain values of the steel material in the linear region with experimental, theoretical and numerical approaches and to examine the suitability of the use of strain gauges for bending, torsion and tensile tests. Three sets (Tension, Torsion and Bending) were prepared in the experimental approach, and strain values were obtained for each experimental set-up. Furthermore, geometric models similar to experimental design were applied to ANSYS finite element program in numerical analyses. Additionally, the strain values were determined theoretically using the full bridge approach in Wheatstone Bridge Theorem. It is thought that assessing the use of the Wheatstone bridge, examining, and comparing the theoretical approaches of different loadings, modelling the appropriate experimental methods in the finite element program, and getting results, and finally interpreting these results, make a valuable contribution to the literature. The strain values were compared. Accordingly, the mean error values between theoretical and numerical for tensile, bending and torsion tests are 5.17%, 4.23% and 6.26%, respectively. The mean error values between the theoretical-experimental results of the same tests were 7.08%, 3.48% and 4.89%, respectively. Consequently, it was seen that experimental, numerical, and theoretical approaches gave more convergence points for each test. [ABSTRACT FROM AUTHOR]

In the next generation of smart cities, Unmanned Aerial Vehicles (UAV) also known as drones are playing a vital role in many advanced applications such as power transmission line inspection, transportation, aerospace and surveillance etc. Due to the excessively high and wide transmission tower heights, the conventional methods of power line inspection are generally ineffective. This manuscript’s primary focus is the development of an autonomous UAV/ quadcopter that can hover over transmission towers and capture photographs and videos by flying along pre-planned routes. Quadcopters have a distinct feature that distinguishes them with the existing aerial vehicles and have a vital role in wide range of applications such as live monitoring of traffic and crowded areas, remote locations, delivery and inspection. This manuscript also explains about the advanced sensors & components such as Global Navigation Satellite System (GNSS), optical flow sensor and Here Link etc. required for fabrication of an autonomous quadcopter for power transmission line applications. The fabricated quadcopter includes a light weight S-500 frame equipped with intelligent controller such as Pixhawk cube orange (2.1) and NVIDIA nano board for receiving and analyzing the data from the onboard sensors and camera based on pre-determined criteria. The proposed approach increases effectiveness and accuracy, has a promising future for intelligent insulator detection and inspection which is a valuable addition to power networks. The suggested deep learning technique has a detection speed of 51.8 frames/sec and a detection accuracy of up to 90.31 percent. The suggested DL algorithm has a promising future in terms of intelligent insulator inspection in power grids. [ABSTRACT FROM AUTHOR]

One of the most common problems encountered in the oil industry is the microbiologically induced corrosion (MIC) of steel equipment by the produced water (PW). In this aspect, PW sample, which is known to contain microorganisms, was taken from Adıyaman oil field and used in corrosion tests of N80 tubing steel. Two different laboratory scale systems, test (with non-sterile PW) and control (with sterile PW), were set up and operated at 70°C over 720 h. For corrosion analysis, the coupons were removed from the laboratory-scale systems at certain time intervals and, gravimetric and electrochemical analyses were carried out. The surface of the coupons was examined by scanning electron microscopy (SEM). The corrosion rates of the test coupons obtained from gravimetric analyses were higher than the control ones during the experiment, and the test coupons were 1.46 times more corroded at the end of the experiment. Additionally, it was determined that the current values of the test coupons were significantly higher than those in the control system (p<0.05). The results of corrosion analyses pointed out that N80 steel was corroded microbiologically. SEM analysis showed that microorganisms were present among the corrosion products. The corrosion data obtained from the control system also indicated that the PW was aggressive for N80 steel. [ABSTRACT FROM AUTHOR]

Copper (Cu) is a ductile material with excellent electrical and thermal conductivity. It is widely used in many industries including automotive, electronics and electricity. However, the mechanical properties of copper are relatively poor. Graphene or graphene nanoplatelets (GNPs) have outstanding properties such as high strength, high young modulus, and large surface area. In this way, they significantly change the mechanical properties when used as reinforcement in metal matrix composites. In particular, in the field of powder metallurgy (PM), the properties of metallic matrix composites produced with these two materials are still under study. In the production of powdered metal components, the type of additive is important in terms of production cost. As the proportion of additives in the manufactured part increases, the production cost will increase accordingly. This study aims to determine which fabrication methods are used to obtain the highest mechanical properties values with the lowest amount of graphene contribution for Cu-GNP composites. The percentages of additives used in the studies are indicated together with the consolidation and mixing methods to prove the above-mentioned purpose. Thus, it has been determined by which production methods the studies with the highest percentage increase in mechanical properties were produced by using the optimum additive ratio for Cu-GNP metal matrix composites. In this regard, the highest hardness value was obtained with 118% increase percentage, by High pressure torsion method. In another study, Electro-co-deposition method were applied. As a result, the highest tensile strength value increased by 110%. The highest increase in yield strength value was obtained by Spark plasma sintering method with 239%. In addition, the effects of different additives were also examined. Other inferences from the studies are given in the result and discussion section. [ABSTRACT FROM AUTHOR]

The present article reviews plasticity, roughness, and oxide-induced crack closure and its direct effect on fatigue crack propagation (FCP) problems. In such cases, plasticity-influenced crack closure significantly influences number of cycles to failure. Thus effective value of crack driving force for fatigue crack propagation problems is dependent upon assessment of plasticity effect both in front of crack tip and in the wake of the advancing crack in the form of appendages of plasticity affected material. Crack closure (through plasticity) is affected by plane stress and plane strain transition, and effect of both types of conditions can be implemented to predict FCP, by taking into consideration appropriate value of plasticity constraint factor. Crack growth under fatigue loading conditions subjected to constant amplitude loading, single overloads, block overloads, variable amplitude loading and random loading is influenced by crack closure effect strongly during transition from plane stress (PSS) to plane strain (PSN) conditions. [ABSTRACT FROM AUTHOR]

This study aims to predict machinability and high performance optimum surface roughness (Ra) by developing multiple regression models and artificial neural network (ANN) model for abrasive water jet cutting (AWJC) of Aluminum 7068 alloy. Important basic processing parameters such as pump pressure (3500-4000 Bar), nozzle distance (2-5 mm), abrasive flow rate (200-350 g/min), abrasive grain size (100-110 mesh), and nozzle traverse speed (240-300 mm/min) were selected in the study. To examine the effects of these parameters on Ra, 32 experiments were conducted using the L32 orthogonal array, and data was collected. Additionally, the most important factors and interactions affecting Ra were determined using multiple regression analysis and analysis of variance (ANOVA). The Artificial Neural Network (ANN) model was designed to have multiple hidden layers using MATLAB. The model was trained and evaluated using experimental data, and its performance was measured using mean squared error (MSE) and mean absolute error (MAE). The model was optimized using hyper parameter tuning and cross-validation techniques. As a result, it was determined that the best R2 value of 95.65% from the multiple regression models created to estimate the surface roughness could be obtained from the linear regression model. While selecting the optimum process parameters for AWJC, it was determined that nozzle rotation speed, abrasive grain size and flow rate had the greatest effect by 35.5%, 25.4% and 21.9%, respectively. The optimized ANN model showed high accuracy in predicting Ra for different input parameter combinations. This study provides a reliable and efficient tool for predicting Ra in AWJC, which can contribute to improving process planning and control. [ABSTRACT FROM AUTHOR]

The Hollow Cylindrical Roller Bearings (HCRBs) have some important advantages over solid cylindrical roller bearings such as low weight, good lubrication capability and high bearing stiffness. Additionally, it's also known that maximum contact stress value between the roller and race is less in hollow cylindrical roller bearings compared to solid cylindrical roller bearings. In this paper, the effect of roller's hollow size in Hollow Cylindrical Roller Bearing under a radial load on the maximum contact stress value and contact stress distribution is studied by using finite element method. The maximum tangential tensile stress occurring on the inner surface of the hollow roller is also investigated. Moreover, the effect of the penetration amount, which is a critical parameter for a nonlinear contact problem such as roller-race contact, on the contact stress is taken into consideration, as well. It's seen from the results that tangential tensile stress on the inner surface of the hollow roller has an effect on the value of optimum hollow size. Besides, it is deduced from results that the penetration amount between the contacting surfaces have considerable influence on the contact stresses and it should be taken into consideration when analyzing the roller-race contact problem by using finite element method. [ABSTRACT FROM AUTHOR]

In this study, an alumina (Al2O3) ceramic coating and a composite coating containing titanium dioxide (TiO2) particles were prepared on surfaces of AA2024 substrates by micro-arc oxidation (MAO) treatment. The effects of micro-sized (≈20-30 µm) TiO2 particles incorporated into electrolyte on the microstructure, phase and chemical composition, thickness, and friction behavior of the coating were investigated. The surface morphologies of the coatings were analyzed by scanning electron microscopy (SEM). The phase and chemical compositions of the coatings were evaluated by means of X-ray diffraction (XRD) and energy-dispersive X-ray spectrometry (EDS), respectively. The friction coefficient of the coatings was investigated using a pin-on-disc tribometer under condition of dry slip sliding. Moreover, the wear tracks were analyzed by SEM. Addition of TiO2 particles into the electrolyte resulted in the reduction in number of pores and formation of smaller and more uniform pores in comparison with the Al2O3 ceramic coating. XRD analyses demonstrated that the TiO2:Al2O3 composite coating was composed of anatase-TiO2 and rutile-TiO2, as well as pure aluminum, α-Al2O3 and γ-Al2O3 which are the primary phases. The friction tests showed a significant reduction in the friction coefficient of the composite coated samples which contains titanium oxide (TiO2) particles in comparison with Al2O3 coated and uncoated samples. [ABSTRACT FROM AUTHOR]

In this study, the creep and stress relaxation behaviors of epoxy nanocomposites reinforced with functional graphene in the viscoplastic deformation regime were investigated. Determining these behaviors, which are important indicators of viscoelastic and viscoplastic behaviors, is critical for durability and reliability in the long-term behavior of polymer-based nanocomposites. The effect of graphene, which has been used in many research fields in recent years and has superior mechanical, thermal, and electrical properties, on these time-dependent behaviors has been experimentally determined. To ensure that the nanocomposites with a content of 0.1 wt% functional graphene remained in viscoplastic deformation, the creep measurement was experimentally measured at 200 MPa constant stress level, and stress relaxation tests were experimentally conducted at 35.5% constant strain level for the 7200s. The results were compared with pure epoxy and observed a 48.5% improvement in creep resistance and a 21.9% improvement in stress drop with 0.1% f-GNF reinforcement to epoxy in the viscoplastic area. In this study, different from the studies in the viscoelastic and yield region generally discussed in the literature, the creep and stress relaxation behaviors of nanocomposites in the viscoplastic area were determined and important results were revealed for the determination of comprehensive material behavior in the design of nanocomposite structures. [ABSTRACT FROM AUTHOR]

The purpose of this research is to improve the dynamic-mechanical properties of the polypropylene filled by artichoke stem (AS) particles and wollastonite (W) in different weight fractions. The effect of weight ratios of fillers in polypropylene was mathematically modeled using the data obtained as a result of the experimental work. In the modeling phase, multiple nonlinear neuro-regression analysis was used. In this context, proposed linear and nonlinear models have been examined by performing R2 training, R²adjusted, R²testing, and boundedness check. The models that satisfy these four criteria were selected as the objective functions for the optimization phase. Finally, Modified Differential Evolution Algorithm was used to obtain maximum storage modulus and loss modulus by adjusting weight percent ratio of artichoke stem particle and wollastonite. The experimental results and the modeling optimization results showed that when the polypropylene-artichoke stem particle-wollastonite hybrid polymer composite was used instead of other non-hybrid polymer composite, the storage modulus and the loss modulus improved by approximately 40%. [ABSTRACT FROM AUTHOR]

The wear behaviour of Al6351 reinforced with 2-8 percent Silicon Carbide (SiC) and 2-8 percent Graphite (Gr) hybrid composite during dry sliding conditions was evaluated using the Taguchi technique with regression analysis. Taguchi with regression analysis can be used to seek the best parameters for hybrid aluminium composites. Wear experiments were conducted using a L9 orthogonal array with the following parameters such as sliding velocity, sliding distance and applied load. The ANOVA (analysis of variance) methodology can be used to determine the impact of each factor. The findings of the investigation revealed that the sliding velocity and load are the two most important factors that determine wear. The extensive experiments are closer to the ANOVA expected values. The Taguchi approach was quite successful in optimising wear parameters, according to confirmation test findings. The influence of each parameter can be identified by ANOVA (Analysis of variance) technique. For Wear the parameter Applied load (L) makes the major support the entire sum of squares 49.57% while sliding speed (S) 37.48% and sliding distance (D) contributes only 0.4% and the factor Applied load (L) 92.29% makes the biggest contribution in frictional force according to ANOVA. [ABSTRACT FROM AUTHOR]

Magnesium is one of the most abundantly available material with good energy efficiency due to less weight. The density of magnesium is 78.5% smaller than steel and 35.6% lighter than aluminum. It is also easy to machine and can potentially be recycled. Since pure magnesium is more prone to corrosion, Magnesium and magnesium alloys are rapidly gaining more attention in multiple applications including automotive, aerospace, electronic and medical fields. The improved physical and mechanical properties of magnesium alloys make these materials as an alternative substitution to aluminum alloys and steel in automotive and aerospace structural applications. Biocompatibility and Biodegradation has given further edge to emerge magnesium alloys as an ideal alternate to the medical implant materials because of improved mechanical strengths when compared to polymeric biodegradable materials. Recent advances in 3C products (Computer, communications, and consumer electronics) also showed an uptrend in the usage of magnesium and its alloys. Based on the studies, the usage of magnesium in various domains is significantly improved in the coming years and can provide a lot of research potentials for the young researchers. Therefore, this paper reassesses the profits of magnesium and its alloy materials in various domains and summarizes the recent works in industrial applications. The potentialities, drawbacks and research scope of magnesium alloys have also been presented towards the development of commercial productsand 23.75% - 83.10%, and lead was adsorbed between 99.35% - 100%, and 72.80% - 92.00%. [ABSTRACT FROM AUTHOR]

The laser engraving process was used to make a gravure on the surface of Ti-6Al-4V alloy. The determinative effect of the laser beam was used to engrave the material on the interaction region using laser engraving parameters. Among the basic laser engraving parameters; scan speed, scan direction, and fill spacing were selected to determine the engraving character of Ti-6Al-4V alloy. The Taguchi L18 orthogonal array was used to set up an experimental layout to analyze the effects of laser engraving on surface roughness and engraving depth. The signal-to-noise ratios for both surface roughness and engraving depth were calculated using the experimental data and also, it was used to decide which factor combination represents the optimal process responses. Further, the analysis of variance was used to decide on the significance of parameters at a 95% confidence level. The results obtained from the analysis of variance revealed that scan speed and scan direction are the critical parameters as p-values are lower than 0.05 and affect the surface roughness by 53% and 19%, respectively. However, scan speed and scan direction affect the engraving depth by 64% and 10%, respectively. [ABSTRACT FROM AUTHOR]

In this study, the aluminum alloys with different MgZn2 contents were prepared using the powder metallurgy method. The effect of the MgZn2 contents on the sintering density, porosity, microstructure and microhardness was investigated using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction, and Vickers microhardness. The function mechanism of the intermetallic compounds formed as a result of MgZn2 addition was analyzed. The results revealed that the highest sintering relative density (95.1%), lowest porosity volume fraction (4.81%), and highest hardness (112.4 HV) were observed with the 5% addition of MgZn2 contents. The XRD results show that the microstructure of the bare sample (Al) is mainly composed α-Al phase, while, with the addition of MgZn2, the microstructure turned to have α-Al phase and some intermetallic compounds of Al5Mg11Zn4 and AlMg4Zn11. These intermetallic compounds were formed with higher density at the grain boundaries as white precipitates. [ABSTRACT FROM AUTHOR]

The present work covers various advancements made in synthesis, characterization and applications of magneto rheological (MR) fluids. It also focuses upon the challenges associated with synthesis of MR fluids, appropriate measures to address the challenges associated with synthesis of MR fluids. Research gaps in the area of MR fluids preparation, characterization are identified and suitable conclusions are drawn based on the body of literature reviewed. From the review of vast literature on MR fluids, the following observations were made. High magnetic saturation, low sedimentation, high shear yield strength, high permeability are some of the desirable characteristics for selection of MR fluids for vast majority of applications. From the literature, carbonyl iron particles are found to be one of the efficient and cost effective MR fluid particles with high magnetic saturation. From recent studies, multi walled Nano tube based anti-sedimentation agents have resulted in high suspension and low sedimentation of MR particles. From some of the latest scientific studies, MR fluids made out of ionic liquids and silicon oils [17] have found to show superior shear yield strength compared to other carrier fluids like mineral oil, synthetic oils. MR fluid with carbonyl iron particle of size 4 µm, suspended in carrier fluid made out of synthetic or mineral oils is found to cater the needs of many applications. [ABSTRACT FROM AUTHOR]

This paper sheds light on the impact of corrosive service conditions on the mechanical and tribological performances of epoxy nanocomposites containing 0.5 wt.% hexagonal boron nitride (BN) nanoplatelets as fillers. The composite samples were aged in 10 wt% H2SO4 solutions by immersion for 504 hours. Variation in mechanical and tribological behaviors during immersion was investigated using tensile and ball-on disk tests. The ball-on disk tests were performed at room temperature under a 10 N constant load and 0.8 m/s speed for 3000 seconds. The high-performance BN nanoplatelets improved neat Epoxy's tensile strength, toughness, and wear performance by 17%, 27%, and 56%, respectively. The aging results revealed that H2SO4 exposure deteriorates the mechanical performance of all epoxy composite samples, even though BN/Epoxy nanocomposites exhibited better resistance to the corrosive environment. In contrast, the tribological performance increased with the acidic solution exposure that acts as a lubricant and forms a corrosive protective layer after the immersion of 504 hours. [ABSTRACT FROM AUTHOR]

Presented is a new method for the realization of a chaotic oscillator in a digital environment. First, a two-stroke sampling mathematical regulation is developed for discrete-time oscillator equations to change signal densities of chaotic signals. This proposed mathematical regulation is applied to Lorenz's chaotic oscillator, which presents a complex dynamical behavior. An application is shown with simulation through a Matlab-Simulink environment with time-dependent density changes of x, y and z 1 - D graphics and x, y 2 - D phase space graphics that are dependent on different density changes. Further to this, in an experimental study, Lorenz's chaotic oscillator's signals with variable density is applied to a DC motor as armature voltage via an 8-bit microcontroller based hardware environment. Chaotic supply voltage is applied to the motor rotor to generate a chaotic angular velocity. Time-dependent density change results of x, y and z 1 - D graphics are obtained and shown on an oscilloscope by converting chaotic rotor angular velocity to electrical signals, through a tacho-generator. The observed results revealed that chaotic signal production with variable density is achieved both in the simulation environment and the experimental environment. Also, it is shown that the proposed program and mathematical equations are feasible in terms of hardware and software implementations. [ABSTRACT FROM AUTHOR]

In the work we obtain some Hermite-Hadamard type inequalities for generalized fractional integrals for convex functions by employing a fractional integral operator, establishing, firstly, a basic identity that is used throughout the work. In addition, some classical integral inequalities are special cases of our main findings. [ABSTRACT FROM AUTHOR]

Honeycombs are essential elements in mechanical systems where low weight and high strength are required. Aluminum and Nomex® are the most commonly used honeycomb materials in structures exposed to compression stress. The primary purpose of this study is to verify the compression behavior of honeycombs in Ls-Dyna using experimental values and theoretical equations. Additionally, it is aimed to evaluate the honeycombs parameters such as cell diameter, cell wall thickness, and material. A correlation matrix was created using the Python/Seaborn program to examine the impact coefficients of the parameters. In this way, the effect of design parameters on compression strength and internal energy was investigated. [ABSTRACT FROM AUTHOR]

In this study, the effect of large deflection on the natural frequency of pre-stressed laminated composite plates with different lamination orientations is investigated. An external distributed vertical load is applied at the free edge of the plate when the other edge is clamped, and then the loading edge of the deflected plate is fixed without removing the load to model a pre-stressed curved plate case. The non - linear deflection curve of the large deflected laminated plate is obtained from the large deflection equation. The large deflection is lim ited to the deflection length corresponding to 25% of the plate length. The thin curved plate is modeled by employing the classical plate theory with a finite element analysis approach. Four different lamination orientations are used which are [0° 0° 0° 0°], [90° 0° 0° 90°], [0° 45° -45° 0°] and [0° 90° 0° 90°], which are used for the examination of large deflection. Besides, the natural frequency parameter of the present model, which is performed in MATLAB, is compared with ANSYS to verify the reliability and validity of the present model. The load parameter that forms the curved plate causes the different mode shapes for each lamination configuration. [ABSTRACT FROM AUTHOR]

This study aims to minimize the friction forces in order to obtain the best feel and minimum effort in the command and control cable part of the shift systems. For this purpose, lubricant, amount of lubricant and application method were investigated. Theoretical and experimental approaches are discussed by examining the studies on this subject. In the presented study, friction measurements were taken in the laboratory environment by applying different amounts of lubrication on the wire exposed to friction, and the amount of lubrication required for minimum effort was determined experimentally. It was observed that the friction force was decreased about 60% with oil running compared to dry running. Studies show that friction forces increase in excessive lubrication as well as in cases where there is no lubrication and little lubrication. The optimum amount of oil was obtained to be 0.1 g. It has developed guidelines for determining the friction factor for those who design shift cable and control cable used in different areas. [ABSTRACT FROM AUTHOR]

Regionalization for precipitation is crucial in locating the area for new dams and the area for extra supplies for both developed and urban employment. Regionalization for precipitation permits the confinement of catchment regions of related precipitation highlights and appearances of the framework elements in the zone. Precipitation areas are found inside the Indus River in Pakistan, which could be observed through precipitation frequencies by methods of Global Wavelet Power Spectrum (GWPS). The effects of precipitation zones are obtained by the method of the GWPS. It showed distinctive recurrence everywhere throughout the basin of a couple of regions; notwithstanding, different frequencies are existing with somewhat essentialness that show changes in the precipitation framework. Our aim is to describe the area of Pakistan region into different sub regions based on cold and hot climate, mountains area, dry and coastal areas with frequency patterns A and B. In this work we found the five sub-areas as Region (1, 2, 3, 4 and 5) with frequency patterns A and B. [ABSTRACT FROM AUTHOR]

A flapwise vibration analysis is performed on a functionally graded tapered rotating beam with tip mass. The beam is considered as functionally graded, whose material properties varying in the direction of thickness. It is assumed as beam is a taper beam with uniform width. Using Mori Tanaka method the properties of the functionally graded material are achieved. The first three f requencies of flapwise are obtained using finite element analysis bas ed software ANSYS. By comparing with the results in open literature, the accuracy of the results is tested. The proposed method yielded good results compared with the existing Frobenious method because of good mesh capabilities. Different parametric studies are carried out to investigate the influence of tip mass on the functionally graded (FG) rotating taper beam flapwise frequencies. The influence of rotating speed, hub radius ratio, gradient index, taper ratio and hub radius ratio on flapwise frequency are elaborated with the support of ANSYS results and analytical models. The results show that the variation in tip mass tends to depress the frequencies from 107.19 Hz to 25.31 Hz at 100 rps in fundamental frequency and in third frequency it is decreased from 336.70 to 332.13 Hz at the same rotational speed. [ABSTRACT FROM AUTHOR]

AA 3003-H24 aluminum alloy plates were butt-welded in order to investigate the effect of friction stir welding process variables on the structural properties of the welded joints. The welded joints were characterized using macro-structural investigations; and tunnel-type defects with varied sizes were detected to occur. At a welding speed of 50 mm/min, tunneltype defects with large size were found to occur in joints welded with the tool rotational speed of 500 and 1000 rpm. The tunnel-type defects were detected to occur in welded joints produced with the process parameters of 80 mm/min welding speed and 500 and 800 rpm tool rotational speed. However, cavity-type defects were observed to occur at both welding speeds. Even, defects were found to occur in the welded joints, all welded joints were detected to fracture between the base metal and the heat-affected zone, except for the joints welded under the process parameters of 50 mm/min welding speed, 500 and 1000 rpm tool rotational speed. The highest ultimate tensile strength among all the welded joints was measured to be 128 MPa produced under the process parameters of 50 mm/min welding speed and 800 rpm tool rotational speed. It has been revealed that there is a good correlation between the size of the defects and the tensile properties of welded joints. An examination on the fracture surface of the welded joints revealed that welded joints were fractured in ductile manner except the joint produced under the process parameters of 50 mm/min welding speed and 500 rpm tool rotational speed. [ABSTRACT FROM AUTHOR]

The widespread use of special stones in the construction industry in recent years makes it necessary to know the properties of these stones well. The stones extracted in Batman region can be used in many areas in the construction sector. It is very important to characterize the physical and chemical properties of these stones and use them under optimum conditions for their successful commercialization. Stone samples were taken from the mine in Batman region; many properties such as porosity, capillary coefficient, thermal conduction coefficient, sound velocity propagation, Shore D hardness test, compressive strength, bending strength, bulk, and grain density were determined. The chemical composition and ratios of Batman stone were determined by XRF analysis. It is seen that this stone is preferred especially in buildings due to its mechanical, thermal, and economic properties. According to the measurement results obtained, as the bulk density of the stone increased, its porosity and thermal conductivity coefficient decreased. It has been observed that as the density increases, the porosity decreases, and Shore D hardness values also tend to increase. The results obtained in the experimental studies and the values found in the theoretical models were compared with statistical analysis. [ABSTRACT FROM AUTHOR]

Impact attenuators are passive safety components that are developed to protect the structural elements of the vehicle and the people inside it. In this study, an impact attenuator is designed for Formula SAE (Society of Automotive Engineering) competition racing car. Due to the SAE regulations, the impact attenuator must absorb 7350 J of collision energy in a frontal collision at a speed of 7 m/s, without resulting in any deformation to the vehicle structural elements. Numerical simulations are performed using ANSYS Workbench finite element software. The material model for the impact attenuator is selected as AA6061-T6 aluminum alloy due to its high energy absorption performance. It is found that the design with varying wall thickness to be the most efficient in te rms of crash force efficiency and spec ific energ y absorption when compared to the basic conical impact attenuator design. A reduction of 64.99% on the maximum impact force, an increase of 58.76% deformation, and an increase of 30.77% crash force efficiency were achieved between the first design and the final design with varying thickness. [ABSTRACT FROM AUTHOR]

One aspect of centrifugal disk settlers comes forward when assessing the sedimentation capability of a unit separation volume, i.e., a single disk interval. Although laboratory analyses of discharged effluent give an approximation as to sediment radii and quantity in unit volume, the fraction of sedimentation at different process parameters such as disk a ngular velocity, particle diameters of interest, throughput rates etc. stand obscure. Towards revealing how centrifugal forces act on the sedimentation process alongside the settler geometry and fluidparticle characteristics, a CFD-DEM model of flow field be tween two adjacent disks at an arbitrary position in disk-stack is presented in this study. Simulations, comprised of particular sediment diameters are conducted at different angular velocities, hence centrifugal forces. Particle sedimentation percentages, also trajectories of each injected particle in different categories are extracted and summarized with an insight on pressure and velocity distributions in the flow field. [ABSTRACT FROM AUTHOR]

Linear and nonlinear numerical techniques are the most popular techniques for finding approximate solutions to initial value problems in numerous scientific fields. Due to the substantial importance of ordinary differential equations, an attempt has been made in the present research study to obtain a new nonlinear hybrid technique based upon contraharmonic and harmonic means having fourth-order accuracy. Theoretical analysis in terms of consistency, stability, asymptotic errors (local and global truncation errors), and convergence has also been carried out. The newly formulated technique is compared with some existing techniques having the same characteristics and observed to be much better because of errors, CPU time, and stability region. The adaptive step-size approach improves the performance of the proposed technique, and strategies to control the errors are developed. Some numerical experiments for scalar and vector initial value problems, including logistic growth, sinusoidal and industrial Robot Arm systems, are presented to show better performance of the proposed technique. [ABSTRACT FROM AUTHOR]

Wire electrical discharge machining (WEDM) technology is a special electrothermal processing method that can precisely production of parts with variable stiffness with sharp edges or production of complex geometric parts which are difficult to produce by traditional manufacturing methods. It has an important place in production sector in terms of low energy consumption. In this study, the relationship between processing parameters on surface quality on the ferritic ductile cast iron (GGG-40) material in WEDM process with molybdenum wire was investigated by Response Surface Methodology (RSM). The aim of this study is to determine the optimum process parameters for low-cost production of GGG-40 material with sharp-edged and complex geometry parts using the WEDM method. In experimental works, surface roughness, and process time were investigated using table feedrate, pulse on time, and pulse space as cutting parameters. The surfaces obtained as a result of the experiments were evaluated in terms of surface quality with Scanning Electron Microscopy (SEM), and surface roughness device. According to the findings, it has been observed that the surface roughness has increased with increasing table feedrate, and pulse on time, and surface roughness decreased with pulse space increasing. Also, it is understood that pulse on time is the most important factor effecting surface quality. It has been found that the process time depends on only the table federate where they are inversely proportional. As result of RSM analysis, optimum cutting parameters were obtained in terms of lowest surface roughness, lowest process time and best time/performance condition on both parameters for ferritic ductile cast iron in WEDM process. [ABSTRACT FROM AUTHOR]

During the machining process, problems such as tool wear, high temperature, force distribution, and surface quality deterioration must be fully understood. Control of these problems with experimental studies and numerical analyses is important in ensuring dimensional accuracy and surface integrity of the cutting tool, workpiece, and also the finished product. The aim of this study is to investigate the effects of machining parameters on chip morphology, residual stresses and tool wear in turning operations of ASTM-F75 CoCrMo alloy experimentally and by finite element method (FEM) simulation. The study was carried out at three different feed rates (0.1, 0.2, 0.3 mm/rev) and at a constant cutting speed of 80 m/min both experimentally on a CNC turning machine and with FEM simulation. From the obtained results, the formation of cracks and adhesions on the surfaces of the chip were observed due to the increase of the feed rate. According to the orthogonal cutting model, chip height ratio (Gs) and tooth pitch (Pc) values of saw-tooth chips supported each other with measurements taken from both FEM images and experimental images. With the increase of the forward speed, the Gs ratio decreased, while the Pc increased. In addition, microscopic images obtained from the cutting tool also showed that the rate of crater wear gradually increased with increasing feed rate. As a result, it is seen that machining parameters have a significant effect on cutting tool and chip morphology in CoCrMo ASTM-F75 alloy turning. [ABSTRACT FROM AUTHOR]

This present study aims to contribute to the literature in understanding the roles of roller burnishing parameters and conditions on Inconel 718 alloy fabricated by Laser Powder Bed Fusion (LPBF). The roller burnishing process was performed with three burnishing forces (300 N, 600 N, 900 N) and under three cooling conditions (namely cryogenic, dry, and preheat). The effects on surface integrity characteristics including surface roughness, microstructure, microhardness, and XRD were investigated. The results illustrate that the burnishing force remarkably influences the decrease the surface roughness under all burnishing conditions. It was possible to reduce the surface roughness from 23 µm to 0.794 µm after turning applied to the as-built part followed by roller burnishing with 900N under dry conditions. When the microstructures were examined, the roller burnishing process caused plastic deformations and reductions in grain sizes. It was observed that the affected layer depth could reach 4.3 µm with 900N under preheat conditions. With the roller burnishing process, it was possible to increase the surface microhardness by 21% depending on the parameter and condition. The roller burnishing process had notable effects on XRD patterns of Inconel 718 alloy fabricated by LPBF. [ABSTRACT FROM AUTHOR]

Lithium-ion (Li-ion) batteries have become popular recently by performing better than conventional batteries. With the advancements in battery technologies, the amount of energy stored by li-ion batteries increases, and important developments occur in control systems. In this article, temperature approaches to the design of advanced electrolyte solutions for Li-ion batteries, electrochemical and electrode effects are examined. As a result of the study, it was observed that the amount of energy stored by Li-ion batteries increased with the developments in battery technologies and that there were significant developments in control systems. [ABSTRACT FROM AUTHOR]

Current study researches the impact of material and forming factors on punch force and sheet thickness in sheet forming of Aluminum 6061 composites. The particular properties of aluminum make it the most excellent candidate to replace the heavier materials in the vehicles which act as reaction to the mass drop interest inside the car area. As of now, the high-heat treatable composites Al 6000 series alloys are applied to broad applications. The forming tests were directed depending upon L27 orthogonal array (OA) planned by taking into account about temperature, die speed, sheet thickness and type of lubricant as input for process parameters. Multi target improvement was done to decide the individual significance of every reaction through Taguchi based Grey Relational Analysis (GRA) along with Principal Component Analysis. The procedure provide the ideal parameter condition for example sheet thickness of 2mm, die and blank temperature of 300oC, die speed of 0.4 mm/s, with Boric Acid lubrication that results in 25.96% decrease in Punch power and thinning improved by 50.74%. ANOVA is valuable to make out the significance and furthermore the result of each cycle factors on response parameters. Though, considerably all the parameters play important role, the die and blank temperature affects 80.11% of the reaction parameters as that of forming factors whereas die speed turned to be the slightest significant factor. Confirmation test was performed for approving the best blend. [ABSTRACT FROM AUTHOR]