Effect Of Thickness Variation Research Articles

Investigation of interface microstructure and mechanical properties of rotatory friction welded dissimilar aluminum-steel joints

The objective of this work is to analyse the effect of variations in IMC thickness and microstructure at interface on the mechanical properties, for the RFW joints of Al6061 and mild steel. Rotary friction welding is a solid-state joining process which is advantageous towards joining of dissimilar materials. The rotary friction welding of Al6061 and mild steel is performed at combinations of two rotational speeds (1200 rpm and 1400 rpm) and three feed rates (10 mm/min, 20 mm/min and 30 mm/min). The microstructural characterization, tensile and hardness testing of the joints is performed. A concave joint interface is noticed due to inhomogeneous plastic deformation along the radial direction from center to workpiece periphery. Similarly, inhomogeneous intermetallic compounds formation along the radial direction at the joint interface is observed, with higher intermetallic compound thickness near the workpiece periphery. The grain refinement on Al6061 side of the interface is attributed to the continuous dynamic recrystallization. Dynamic recovery is noticed at the mild steel side. The crack initiates at the IMC rich region near the periphery and follows the IMCs to grow radially inwards. Along the radial direction from periphery to the center, the reduction in IMC thickness and increase in DRX region thickness resists the growth of the crack. Brittle failure is observed in the IMC rich regions near the periphery and ductile failure is noticed near the center. An increase in IMC thickness reduces the joint strength and wider DRX region improves the joint strength. This combination led to the maximum tensile strength for the joints prepared with intermediate feed rate of 20 mm/min. A maximum joint tensile strength of 136 MPa is achieved, which corresponds to 65 % joint efficiency.

Static and modal analysis of sine-wave-shaped spar

Sine-Wave-shaped Spar (SWS) is recently involved in wing design as one of the corrugated shaped spars that highly improve the torsion and buckling resistance. SWS is an I-beam made of sine wave shaped vertical web fixed to upper and lower flanges. The current research evaluates the behavior of SWS in comparison to the traditional straight-web spar in resisting two cases of loading; static bending loading and static torsion loading. For each case, deformation and stress are analyzed. Modal analysis is also performed for the two spar configurations. For this purpose, a finite element model is developed using Ansys Workbench software for the SWS and the straight web spar. To reach a fair comparison, similar weight is considered for the two spar structures. A parametric study is performed to investigate the effect of web thickness and flange thickness on the bending and torsion deformation and stresses. The effect of thickness variation on the natural frequencies and mode shapes is also considered. The current study can be considered a base to design wing spars that combine the merits of the two spar configurations.

Effect of variations in layer thickness and resilience modulus on flexible pavement performance

A pavement mechanistic-empirical analysis is based on a pre-designed structure checked for required performance criteria. In case the latter are not met, this structure is modified and reprocessed. In this context, analyzing the effect of variations in project parameters on pavement performance prediction subsidizes a better understanding of results provided by computer programs. The objective of this study is to assess the effect of layer thickness and resilience modulus variations on flexible pavement performance. To do so, performance was estimated for the 20th project year through Elastic Layered System Model 5 (ELSYM5) software and American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical method (ME). Using multiple regression models for result adjustment and through statistical assessments on regression coefficients calculated, it can be concluded that pavement lifespan consumption, predicted by simulations on ELSYM5, is sensitive to variations in coating and subbase thickness and in subgrade resilience modulus. For AASHTO ME method, predicted values for distresses were significantly sensitive to variations in coating, base and subbase thickness, and in base and subgrade resilience modulus. Comparing both approaches, it is concluded that ELSYM5 can be a viable alternative to the application of a ME pavement design method.

Effect of blade thickness on rotating stall of mixed-flow pump using entropy generation analysis

In a mixed-flow pump, the energy performance curve always appears as an unsteady region under rotating stall condition. In this paper, computational fluid dynamics (CFD) technology is employed to study the effect of variation in blade thickness of the impeller for the purpose of improving the stall characteristics of the mixed-flow pump. The local loss caused by the turbulent flow is investigated using the entropy generation method that considers the wall effects. The results show that the stall region of mixed-flow pump is closely related to the blade thickness, and the total entropy generation (TEG) in impeller and guide vane are affected. At design flow rate, the tip leakage vortex (TLV) accounts for most of the hydraulic loss in the impeller and the change in the blade thickness does not influence the pump head or efficiency significantly. Whereas, within stall region, the stall vortex and TLV determine the high TEG region in the impeller, the backflow and secondary flow are the source of major hydraulic loss in the guide vane. A small increase in the blade thickness reduces the loss caused by the stall vortex which delays the stall point. However, once the blade thickness increases significantly, the stall vortex becomes bigger which deteriorates the flow fields in the impeller and guide vane resulting in rotating stall. Thus, the blade thickness can be considered as a key parameter to minimize the occurrence of rotating stall in a mixed-flow pump for improving its efficiency and safety.

Simulation and optimization of green organic light emitting diode based on TiO2/Ag/MoO3 multilayer electrode

In this paper, first, multilayer features of TiO2/Ag/MoO3 (TAM) are investigated as a transparent conductor structure alternative to Indium Tin Oxide (ITO) electrodes. Thickness effects on the electro-optical features are investigated and an optimal structure is designed. A maximum figure of merit (FOM) of 1.2 × 10-2 (Ω−1) was calculated for a asymmetric TiO2(45 nm) /Ag(10 nm) /MoO3(40 nm) multilayer. By considering an Organic Light Emitting Diode (OLED) based on TAM trilayer electrode with TiO2/Ag/MoO3/TPD (N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine)/Alq3 (tris(8-hydroxyquinolinato) aluminum)/Al, the effect of variation in different layers thickness on OLED device are studied. Different output features are investigated using thin-film optics and OLEDs optical models based on microcavity and interference effects. The results showed that it is possible to tune output light, intensity, spectrum width, and the wavelength for intensity peak with respect to each of the layers thickness. Finally, the ultimate structure of such device based on TAM is suggested to be TiO2(45 nm)/Ag(10 nm)/MoO3(10 nm)/TPD(40 nm)/Alq3(50 nm)/Al, in which the optimal emission zone is located at the interface between the emitting and hole-transporting layers. Finally, the TAM-based OLED with optimized structure and OLED with ITO electrode were fabricated to compare and evaluate the results obtained from the simulation. The results show that OLED prepared on TAM anode has lower turn-on voltage, higher luminance intensity, higher current efficiency and higher power efficiency compared to the ITO-based device.

Optimisation of dielectric spacer layer thickness in Ag nanospheres/ITO/c-Si structure for plasmonic solar cells using FDTD simulation

ABSTRACT The thickness of dielectric spacer layer (DSL) plays an important role in performance of plasmonic solar cells. In this work, effect of thickness variation of ITO (indium tin oxide) DSL in silver (Ag) nanospheres/ITO/crystalline silicon(c-Si) structure on forward and backward scattering efficiencies has been investigated. Simulations were carried out using the open-source software MEEP via FDTD method for Ag nanospheres of sizes 50nm, 80nm and 100nm. Maximum forward scattering was observed with 80nm thickness of ITO DSL for all sizes of Ag nanospheres. Transmittance at ITO/c-Si interface and spatial distribution of electric field have been investigated for optimised thickness of ITO DSL. In visible to near infra-red region, maximum transmittance was exhibited by 100nm Ag nanosphere. Enhanced electric field has been observed with increasing size of nanosphere. This study provides us an optimum value of ITO DSL thickness in Ag nanospheres/ITO/c-Si structure to fabricate a photovoltaic device with upgraded efficiency.

The Strength and Delamination of Graphene/Cu Composites with Different Cu Thicknesses

This study analyzed the mechanical and fracture behavior of graphene/copper (Cu) composites with different Cu thicknesses by using molecular dynamics (MD) and representative volume element (RVE) analysis. Three graphene/Cu composite analytical models were classified as 4.8, 9.8, and 14.3 nm according to Cu thicknesses. Using MD analysis, zigzag-, armchair-, and z (thickness)-direction tensile analyses were performed for each model to analyze the effect of Cu thickness variation on graphene/Cu composite strength and delamination fracture. In the RVE analysis, the mechanical characteristics of the interface between graphene and Cu were evaluated by setting the volume fraction to 1.39, 2.04, and 4.16% of the graphene/Cu composite model, classified according to the Cu thickness. From their obtained results, whether the graphene bond is maintained has the greatest effect on the strength of graphene/Cu composites, regardless of the Cu thickness. Additionally, graphene/Cu composites are more vulnerable to armchair direction tensile forces with fracture strengths of 14.7, 8.9, and 8.2 GPa depending on the Cu thickness. The results of this study will contribute to the development of guidelines and performance evaluation standards for graphene/Cu composites.

Analysis of the Effect of Abrasive Material and Polyurethane Coating Thickness Variations on ASTM A36 Steel Towards Corrosion Rate in Sea Water Environment

An unavoidable phenomenon of using steel as the main material in offshore structures and floating vessels is corrosion. One method of preventing corrosion is by coating and using polyurethane is one type of coating that is currently being developed in the maritime industry. But the success of this coating process is very dependent on the surface preparation process. The usual method used is blasting using an abrasive material. This study aims to find the response to the corrosion rate of polyurethane coating with thickness variations of 60 µm, 80 µm, and 100 µm by first blasting using abrasive material variations in the form of silica sand and steel grit. The result of the corrosion rate test showed that the lowest corrosion rate value was obtained in the variation of abrasive material in the form of steel grit. with a 100. µm of polyurethane coating thickness, that is 0,00008 mm/a. While the highest corrosion rate value was obtained in the variation of abrasive material in the form of silica sand with a 60 µm of polyurethane coating thickness, that is 0,02202 mm/a.

Effect of Thickness Variation of the N-Type Layer in CdS/CdTe Solar Cell

Effect of Thickness Variation of the N-Type Layer in CdS/CdTe Solar Cell

Effect of layer thickness variation on sensitivity: An SPR based sensor for formalin detection

Food preservatives and additives are the universal concern of recent days. Particularly, formalin is a chemical compound that is being commonly mingled with food for the preservation purpose. The recurrent ingesting of formalin contaminated food causes uncompromising health sicknesses like chronic cancer. Therefore, identification of formalin in food substances is an extreme need and day by day this need is growing as a general issue in the emerging terrains. In this article, a surface plasmon resonance (SPR) based sensor, comprised of graphene-PtSe2 combined layers associated with a ZnO nano-sheet is presented for the detection of formalin in liquid solution. The performance of the sensor has been analyzed through an analytical approach using MATLAB commercial software. Consequence due to incorporation of the Graphene-PtSe2 combined layer into the sensor structure along with ZnO layer has been studied. The observed sensitivity and quality factor are 155.33° RIU−1 and 88.89 RIU−1, respectively. This sensor senses the presence of formalin molecules by using attenuated total reflection (ATR) approach, assessing the reflectance vs SPR angle. It is found that the sensitivity of the conventional SPR based sensor is 128.33° RIU−1, whereas an improved sensitivity of 155.33° RIU−1 is obtained for this proposed amalgamated sensor structure. Later in time, a comparison of performance for different SPR sensor structures and the proposed sensor has been studied. Finally, another comparison study has been made with performance of the proposed sensor to other reported sensor in the literature.

Monte Carlo simulation to assess free space and end-weld thickness variation effects on dose rate for a new Ir-192 brachytherapy source

A new Iridium-192 seed for brachytherapy is under development. Specific dose rate contribution by two different factors were evaluated: the effect from movement of the core in the free space within the seed and the effect of the end-weld thickness variation. Both were investigated through use of the Monte Carlo radiation transport code MCNP6 and an in-house routine programmed with MATLAB. Differences greater than 15% compared to results from the nominal seed were found near the source, indicating a significant dose variation.

Numerical Study of Laterally Loaded Piles in Soft Clay Overlying Dense Sand

This paper presents the results of three dimensional finite element analysis of laterally loaded pile groups of configuration 1×1, 2×1 and 3×1, embedded in two-layered soil consisting of soft clay at liquid limit overlying dense sand using Plaxis 3D. Effects of variation in pile length (L) and clay layer thickness (h) on lateral capacity and bending moment profile of pile foundations were evaluated by employing different values of pile length to diameter ratio (L/D) and ratio of clay layer thickness to pile length (h/L) in the analysis. Obtained results indicated that the lateral capacity reduces non-linearly with increase in clay layer thickness. Larger decrease was observed in group piles. A non-dimensional parameter Fx ratio was defined to compare lateral capacity in layered soil to that in dense sand, for which a generalized expression was derived in terms of h/L ratio and number of piles in a group. Group effect on lateral resistance and maximum bending moment was observed to become insignificant for clay layer thickness exceeding 40% of pile length. For a fixed value of clay layer thickness, lateral capacity and bending moment in a single pile increased significantly with increase in pile length only up to an optimum embedment depth in sand layer which was found to be equal to three times pile diameter and 0.21 times pile length for pile with L/D 15. Scale effect on lateral capacity has also been studied and discussed. Doi: 10.28991/cej-2021-03091686 Full Text: PDF

MoOx work function, interface structure, and thermal stability analysis of ITO/MoOx/a-Si(i) stacks for hole-selective silicon heterojunction solar cells

Silicon heterojunction (SHJ) solar cells are gaining prevalence owing to their high conversion efficiency and simple, low-cost, and industrially compatible fabrication process. However, the high parasitic absorption exhibited by the doped amorphous silicon a:Si(p/n) layer substantially limits their performance. This can be alleviated by substituting traditional amorphous doped p/n layers with alternative materials such as transition metal oxides. MoOx is one of the most promising candidates for replacing the a:Si(p) layer, and it has yielded impressive results in recent studies; however, the thermal instability of MoOx-based devices is a major limitation. In this work, the MoOx work function, thermal stability of the ITO/MoOx/a-Si(i) interface, and the effect of MoOx thickness variation on the performance of a MoOx SHJ solar cell were thoroughly studied. The MoOx composition and work function were analyzed using X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and ultraviolet photoelectron spectroscopy. The O2-treated MoOx film showed minimal oxygen deficiencies accompanied by a higher work function of 6.22 eV compared with those of H2-, N2-, and Ar-treated MoOx films. The ITO/MoOx/a-Si(i) stacks have a clear contact interface up to 150 °C and in-out diffusion between the layers is initiated upon further increase of the annealing temperature. Thus, 150 °C was proposed as the optimal temperature and used for Ag paste sintering without degrading the device performance. Additionally, a thin sub-stoichiometric SiOx layer was formed on a-Si(i) during MoOx deposition, irrespective of the annealing environment, temperature, and thickness of MoOx. The fabricated SHJ solar cell with an optimized thickness of MoOx (7 nm) exhibited an efficiency of 19.86% with a Voc of 716 mV, Jsc of 37.50 mA/cm2, and FF of 74.01%. The achieved Jsc is 1.40 mA/cm2 higher and the external quantum efficiency in the range of 300–600 nm is 13%–15% higher than those for the reference SHJ solar cell. Therefore, our results show that MoOx is an efficient and convenient alternative emitter material for Si solar cells, and the proposed optimized parameters for MoOx processing pave the way for more efficient SHJ solar cells.

Effect of variation in channel length and thickness of organic semiconductor in the bottom-gate configuration of OTFT

Advancing in the device and circuit performance a vast amount of study is going in the area of organic electronics. In the present work, we have patterned the features of the bottom-gate configuration of OTFT with the help of Technology Computer-Aided Design (TCAD) tools where ATLASTM (Silvaco International) has been utilized as a 2D numerical device simulator to extract the electrical characteristics. To monitor the effect of variation in channel length and thickness of OTFT, we have altered the channel length (L) from 10um to 50um, which results in the reduction of the drive current from -1.4 × 10-10 A to -2.7 × 10-11 A (BGBC), and in contrary to that the performance of the device has been affected as the current ratio decrease from 1.2 × 1012 to 1.4 × 103 (BGBC) with a thickness variation of organic semiconductor from 10nm to 50nm. Furthermore, the electrical characteristics as well as performance parameters like mobility, on/off current ratio, threshold voltage, etc., related to configured Bottom-Gate (top and bottom contacts) pentacene-based OTFT devices have been retrieved and compared.

An analysis of tube thickness effect on shell and tube heat exchanger

Heat exchangers are important equipment for the process of placing heat. The most widely used type of heat exchanger is shell and tube. This type is widely used because of its simple and easy design. Design of shell and tube heat exchangers is done by the side or shell variations to get the desired performance. Therefore, research is conducted to study the effect of tube thickness on heat transfer, pressure drop, and stress that occurs in the shell and tube heat exchanger so that the optimal tube thickness is obtained. In this research, the activities carried out are the design of heat exchangers for the production of oxygen with a capacity of 30 tons/day. The standard used in this study is the 9th edition heat exchanger design guidance document compiled by the Tubular Exchanger Manufacturer Association (TEMA). Analysis of the tube thickness effect on heat transfer, pressure drop, and stress was carried out using the SimScale platform. The effect of variations in tube thickness on heat transfer is that the thicker the tube, the lower the heat transfer effectiveness. The highest value of the heat exchanger effectiveness is 0.969 at the tube thickness variation of 0.5 mm. The lowest value of the heat exchanger effectiveness is 0.931 at the tube thickness variation of 1.5 mm. The effect of variations in tube thickness on pressure drop is that the thicker the tube, the higher the pressure drop. The highest value of pressure drop is in the variation in tube thickness of 1.5 mm, 321 Pa. The lowest value of drop pressure is in the variation of 0.5 mm tube thickness, which is 203 Pa. The thickness of the tube also increases the maximum stress on the components of the shell, head, tubesheet, baffle, and saddle, but the value is fluctuating

Efficient excitation of novel graphene plasmons using grating coupling

Excitation of novel graphene plasmons is examined using finite-element analysis via COMSOL RF module 5.6. The theoretical model is simulated with graphene grating on the glass substrate having fixed periodicity (Λ = 700 nm) by illumination with transverse magnetic (TM) polarized light through the substrate side. The effect of thickness variation on SPPs excitation has been acquired from transmission spectra while keeping the periodicity and slit width of grating structure constant via analyzing the trend followed by the resonance dips. The electric and magnetic field behavior has also been analyzed for each thickness, and a specific grating thickness of 10 nm was taken into consideration owing to the thickness constraints regarding graphene. Slit width variation of the grating structure has been investigated using far-field analysis to observe the formation of SPPs from transmission spectra and near-field analysis for understanding the underlying physics. These analyses resulted in SPP excitation more appreciable at slit widths in between 250 and 350 nm. The slit width range regarding the chosen periodicity supports the most efficient plasmonics mode and many applications of such devices are found in real life.

Twyman effect in thin curved optics: effects of variable thickness and curvature.

Grinding or finishing of thin curved optics introduces surface-localized stresses that may result in bending deformations, thus affecting optical performance (Twyman effect). The Twyman effect depends on local thickness of the optic as well as its curvature. We use numerical and analytical techniques to assess the effects of these variables for shallow and deeply curved axisymmetric optics. A useful metric of comparison, valid for shallow optics, is the deformation of a similar flat optic (window). This comparison is inadequate for more curved optics, which demonstrate a smaller deformation that is now localized in a boundary layer near the optic-free edge. The effects of thickness variation are also presented. Normal deflection and slope for a positive optic (thickness at the center greater than the tip) are well approximated by a constant thickness optic. This is not the case for a negative optic, where deformations near the apex are more pronounced, thus extending significant deformations through the full optic aperture.

Effect of SiO2 Thickness Variation on Threshold Voltage and Trans-Conductance of TFT

Effect of SiO2 Thickness Variation on Threshold Voltage and Trans-Conductance of TFT

Effect of variation in thickness of phase change material on temperature across the composite building wall

In this paper, the impact of thickness of a bio-phase change material (b-PCM) and its effectiveness towards thermal execution and comfort of a building wall is studied using ANSYS. Two models have been simulated among which the primary model is a reference room which do not contains b-PCM and the secondary model is one including b-PCM with varying thickness. A b-PCM can more constructively decrease the heat transfer to the inner side room due to lower thermal conductivity and higher latent heat of phase change. In addition, the thermal conductivity has need over other PCM thermo physical properties. The lower thermal conductivity of PCM allows lower amount of heat to the inside room space. The observations of present work reveal the information that the expansion of PCM layer thickness has significant impact for delivering a higher temperature contrast, past specific timings of the peak surrounding temperature. Likewise, the utilization of PCM empowers better ability to hold starting temperature for longer timeframe.

Effect of variation in Temperature, Band gap and Thickness of Active Layer on Efficiency of Organic Solar Cell

Effect of variation in Temperature, Band gap and Thickness of Active Layer on Efficiency of Organic Solar Cell