Effect Of Thickness Variation Research Articles

Knee-Loading Predictions with Neural Networks Improve Finite Element Modeling Classifications of Knee Osteoarthritis: Data from the Osteoarthritis Initiative.

Physics-based modeling methods have the potential to investigate the mechanical factors associated with knee osteoarthritis (OA) and predict the future radiographic condition of the joint. However, it remains unclear what level of detail is optimal in these methods to achieve accurate prediction results in cohort studies. In this work, we extended a template-based finite element (FE) method to include the lateral and medial compartments of the tibiofemoral joint and simulated the mechanical responses of 97 knees under three conditions of gait loading. Furthermore, the effects of variations in cartilage thickness and failure equation on predicted cartilage degeneration were investigated. Our results showed that using neural network-based estimations of peak knee loading provided classification performances of 0.70 (AUC, p < 0.05) in distinguishing between knees that developed severe OA or mild OA and knees that did not develop OA eight years after a healthy radiographic baseline. However, FE models incorporating subject-specific femoral and tibial cartilage thickness did not improve this classification performance, suggesting there exists an optimal point between personalized loading and geometry for discrimination purposes. In summary, we proposed a modeling framework that streamlines the rapid generation of individualized knee models achieving promising classification performance while avoiding motion capture and cartilage image segmentation.

Analysis of the recording of Fibonacci lenses on photopolymers with 3-D diffusion model

In this work a three-dimensional diffusion model is used to model photopolymers as a recording media. This model allows us to predict the properties of the Diffractive Optical Elements (DOEs) once we recorded into the photopolymer. This model had never been tested with more complex elements, such as multifocal diffractive lenses, as presented in the following in this work. In addition, the model includes; the estimation of the refractive index modulation, the low-pass filtering effect due to the experimental optical setup, and the evolution of the transverse intensity distribution. In this way, the selection of the appropriate material characteristics depending on the intended DOE application is made possible. Specifically, an acrylamide-based PVA/AA photopolymer is simulated using the proposed model. Moreover, coverplating and index matching systems are considered together to avoid the effects of thickness variation. Furthermore, in order to compare their properties using the proposed model, we focus on Fibonacci lenses (FL), a type of bifocal lenses. This allows us to evaluate the dependence of the focii intensity on the polymerisation rate, the diffusivity parameter, low-pass filtering effect and the use of the index matching system for these lenses. This enables us to know the recording parameters in order to produce this type of multifocal diffractive lenses with higher quality and precision.

Effect of Pad Thickness and Width Variations on Plastic Limit Moment in Cylindrical Pressure Vessels Due to Nozzle In-Plane Load

This study investigates how different pad thicknesses and diameters affect the maximum stress a cylindrical pressure vessel can handle without failing, particularly around the areas where nozzles are attached. Nozzles on these vessels often face directional stress from loads applied in a specific plane, and these stresses mustn’t push the nozzle material beyond its breaking point. The research used computer simulations to see how these vessels, with various pad sizes and a set shell and nozzle size, behave under increasing stress until they reach their breaking point. Findings indicate that making the pad thicker or wider increases the vessel’s resistance to breaking up to a certain point; beyond this optimal size, making the pad larger doesn’t provide any additional benefit. This information helps design better and safer pressure vessels by identifying the best pad size to prevent failure. The study contributes to understanding how to avoid design issues and optimize the construction of these vessels, adhering to specific industry standards.

New Numerically Derived Scaling Relationships for Impact Basins on Mars

AbstractMost impact basins are believed to have formed during the early epochs of planetary evolution. The planet's gravity, internal structure, and thermal regime have the strongest control over their formation. Because of this, we can use the geophysical constraints on Mars' interior composition, structure, and geophysical evolution derived from the InSight mission to better understand the formation of impact basins on the planet. To achieve this, we performed numerical simulations of large impacts using the iSALE shock physics code. We investigated the effects of temperature and crustal thickness variations on impact basin size and morphology. Our scaling relationships indicate that: (a) basins formed in a warmer crust have larger final diameters in comparison to basins formed in a colder crust, a difference that is further accentuated as basin size gets bigger; and (b) the largest impact basins on Mars were created by impactors ranging from 35 to 680 km in diameter, up to ∼32% larger than estimates based on classical scaling. Our results expand the current understanding of the extent of early and large impact bombardment on Mars and provide a more comprehensive knowledge of impact basin formation on planetary surfaces.

Effect of thickness on fatigue behavior of L-PBF fabricated Ti-6Al-4V alloy using a novel specimen geometry

One of the most promising advantages with additive manufacturing is the ability to fabricate complex geometries. These geometries can have significant impacts on thermal histories, microstructures, defects, and fatigue behavior. This study aims to investigate the effects of thickness variation on the fatigue life of AM fabricated components subjected to uniaxial loading through the introduction of a novel specimen geometry. The geometry is designed with a constant cross-sectional area and varying thicknesses by changing the diameter, ensuring constant stress throughout the gage section. Results found minimal relationship between the thickness and fatigue behavior for the as-built surface condition.

Azimuthal Fourier decomposition for loss analysis of hollow-core tube lattice fibers part I: Ideal fibers

This is the first part of two papers where we propose and apply a methodology for confinement loss analysis in tube lattice fibers (TLFs). The methodology is based on azimuthal Fourier decomposition (AFD) of the fiber’s cladding and core modes along the perimeters of the cladding tubes composing. This technique, combined with coupled mode theory, constitutes an effective approach to gain insight in the inhibited coupling waveguiding mechanism and design, along with fiber non-idealities impact on confinement loss. In this part I, we describe the approach and apply it to loss analysis of ideal TLFs. The approach is then applied to the analysis of the effects of tube thickness variation in part II.

Effects of thickness variation due to presence of roller wake on the thickness measurement using laser ultrasonic technique

Effects of thickness variation due to presence of roller wake on the thickness measurement using laser ultrasonic technique

Inkjet-printed transistors with coffee ring aligned carbon nanotubes

Low-concentration deposition techniques such as inkjet printing for forming carbon nanotube (CNT) transistor channels typically result in higher on–off current ratio, while lowering the field-effect mobility compared to traditional high-concentration techniques. In this paper, we show that inkjet-printed devices can have both high field-effect mobility and on–off current ratio by utilizing coffee ring induced thickness variation in the channel. The coffee ring effect occurs naturally in printed patterns with most solvents and substrates, and it pushes dissolved particles to the edges of printed features. Thickness variation and coffee ring effect are usually avoided in the channel of solution processed thin-film transistors by implementing additional expensive steps in the fabrication process. Instead, here, we control these variations and utilize them to create inkjet-printed CNT channels with printing induced thickness variation that improves transistor properties. Printing properties such as printing speed, and number of layers are studied to manipulate capillary flow and form thicker line edges, which ultimately enhance current transport in the CNT network. A two-pass printing pattern with separate lines improves the field-effect mobility five times compared to a pattern with connected lines that has no defined edges. The field-effect mobility increases from 1.1 to 5.7 cm2 V−1 s−1 at a drain voltage of −2 V.

Effects of Coupled Thickness Variation on the Aeroelastic Performance of Continuous Tow Sheared Composite Wing

Effects of Coupled Thickness Variation on the Aeroelastic Performance of Continuous Tow Sheared Composite Wing

Effect of carbon allotropes and thickness variation on the EMI shielding properties of PANI/NFO@CNTs and PANI/NFO@RGO ternary composite systems.

The innovative design of thin, multiphase flexible composite systems with good mechanical properties, low density and improved EMI shielding properties at low filler content has become a key area of research. In this work, we report the low temperature synthesis of three-dimensional ternary composites (PANI/NFO@CNTs and PANI/NFO@RGO) by oxidative chemical polymerization of aniline in the presence of two different binary composites, viz. NFO@CNTs and NFO@RGO. Enhanced impedance matching is achieved by varying the ratio of the carbon allotropes (CNTs and RGO) to the ferrite component. The synthesis of NFO, PANI/NFO@CNTs and PANI/NFO@RGO is validated by XRD and FTIR spectroscopy. Field emission scanning electron microscopy (FE-SEM) confirmed the synthesis of core-shell structures of PANI/NFO@CNTs and PANI/NFO@RGO, where the binary composites (NFO@CNTs and NFO@RGO) serve as a core onto which a tubular PANI layer was coated. Shielding effectiveness of 22.36 dB (99.41% attenuation) is exhibited by the ternary composite PANI/NFO@CNTs (8 : 1), while for PANI/NFO@RGO (20 : 1) a total shielding effectiveness of 31 dB equivalent to 99.92% attenuation was observed at a thickness of 2 mm. The ternary composite PANI/NFO@RGO (20 : 1) 4 mm showed a maximum SET of 43 dB corresponding to 99.996% attenuation of incident EM waves. The enhanced EMI shielding properties of the synthesized ternary composite systems are accredited to good impedance matching, effective dielectric and magnetic loss mechanisms and good conductivity, which facilitate multiple reflections and scattering of incident radiation.

Influence of various damage mechanisms on the low‐velocity impact response of composite laminates

AbstractThis study exhibits the effect of different damage mechanisms on the mechanical behavior of composite laminates subjected to low‐velocity impact load. To achieve this, seven low‐velocity impact energies were applied to laminates with five different thicknesses and four unique stacking sequences. The extent of damage was quantitatively evaluated through contact measurements and ultrasonic C‐scan techniques. Numerical simulations, showing good agreement with experimental results, characterized the distribution and evolution of damage within the laminates. The findings reveal that when matrix and delamination damage are predominant, the dent depth increases slowly and is visually invisible, while the delamination area expands almost linearly. Conversely, When fiber damage prevails, the laminate absorbs more energy, leading to rapid increases in dent depth, the appearance of visible cracks, and the occurrence of sharp fluctuations with multiple peaks in contact force and displacement curves. Nonetheless, the delamination area and projection tend to be stable and unchanged. Furthermore, alterations in thickness and stacking sequence directly affect the damage characteristics and energy absorption properties. This research offers valuable theoretical insights and serves as a reference for enhancing the comprehension of the failure mechanism of laminates and optimizing their performance.Highlights Demonstrate the utility of dent depth in identifying changes in damage mechanisms. Evaluate the delamination damage of laminates after impacts by ultrasonic C‐scan techniques. Reveal the regulation of impact response parameters for different damage mechanisms. Investigate the effect of variation in thickness on damage characteristics and energy absorption. Evaluate the impact resistance of laminates with different stacking sequences.

The stability of cratons is controlled by lithospheric thickness, as evidenced by Rb-Sr overprint ages in granitoids

The ancient cores of modern continents, cratons, are the oldest blocks of “stable” lithosphere on Earth. Their long-term survival relies on the resistance of their underlying thick, strong, and buoyant mantle keels to subsequent recycling. However, the effect of substantial geographical variations in keel thickness on the post-assembly behaviour and mass movement within these continental cores remains unknown. Here, we demonstrate that the spatial distribution of fluid-reset in-situ Rb-Sr ages for Paleo-Mesoarchean (3.6–2.8 billion years ago; Ga) granitoids of the Pilbara Craton, Australia shows remarkable correlation with independently-constrained lithospheric thickness models. Without craton-wide heating/magmatic events, these anomalously young Rb-Sr ages document episodes of fluid infiltration into granitoid complexes as a response to lithospheric reactivation by far-field stresses. This correlation implies that craton-wide fluid mobilization triggered by extra-cratonic Neoarchean to Mesoproterozoic (2.8–1.0 Ga) tectonic events is facilitated by variations in lithospheric strength and thickness. Compared to areas of older overprints, the two-thirds of the craton comprised of younger reset ages is underlain by comparatively thin lithosphere with higher susceptibility to reactivation-assisted fluid flow. We propose that even the strongest, most pristine cratons are less stable and impermeable than previously thought, as demonstrated by the role of granitoid complexes and cratons as selective lithospheric “sponges” in response to minor tectonic forces. Therefore, variations in lithospheric thickness, likely attained before cratonization, exert a crucial control on billions of years of fluid movement, elemental redistribution and mineralization within ancient continental nuclei.

Bending analysis of glass fiber reinforced epoxy composites/copper-clad laminates for multi-layer printed circuit boards

Printed circuit board (PCB) is the most important part of any electronic device which is made of copper-clad laminate and glass fiber-reinforced composites. Since the ply orientation of fiber-reinforced composites and lamina thickness have a significant influence on the mechanical properties of the whole composite laminate it is necessary to investigate the effects of ply orientation and lamina thickness on the bending properties of PCB so that they can be manufactured to meet the service requirements. In this work, the bending properties of PCB were investigated for seven different ply orientations of glass fiber-reinforced composite laminas and for eight different thickness combinations (for a constant laminate thickness) of glass fiber-reinforced composite lamina and copper-clad laminate. A commercially available finite element analysis software (Abaqus) was used to simulate a three-point bending test of PCBs and the simulation results were validated using experimental results. It is found that the bending stiffness is maximum for the cross-ply laminate. The introduction of angle ply improves the maximum von-Mises stress of the PCB with an insignificant cost of bending stiffness (less than 5% reduction). It is found that the bending stiffness and the maximum von-Mises stress of the PCB can be regulated through the variation of thickness of the constituent lamina. The laminate stiffness can be increased by increasing the thickness of stiffer laminas or by placing the stiffer laminas towards the surface of the laminate. The outcome of this research would provide a comprehensive understanding of the bending characteristics of the multi-layered PCBs which can be directly utilized by the PCB manufacturers. However, the effects of ply orientation and lamina thickness variation on the behavior of the PCBs subject to temperature variation, impact loading, vibration, and other conditions that might affect the service life of the PCBs should be investigated.

The Effect of Slice Thickness Variation on The Anatomical Information of CT Scan Paranasal Sinus Coronal Section in Clinical Rhinosinusitis

CT Scan is an excellent technique in assessing anatomical structures, anatomical abnormalities, and visualising the presence or absence of pathological tissue in the four sinuses and their extensions. One of the important parameters on CT Scan is slice thickness. Slice thickness is a thickness of the slice that can be adjusted according to clinical requirements with a variation of values from 1 to 10 mm. The purpose of this study is to determine the effect of slice thickness variation on anatomical information of CT Scan paranasal sinus coronal section in rhinosinusitis and slice thickness variation that produces the most optimal anatomical information. This study is an analytical quantitative study with an experimental approach conducted on 10 samples who performed CT scan examination of paranasal sinus in rhinosinusitis using slice thickness variations of 0.6 mm, 1 mm, 1.5 mm and 2 mm. Based on the results of Friedman test and Wilcoxon Post Hoc test, the p value is 0.0001 (p&lt;0.05) which means there is an effect of using slice thickness variation on anatomical information. The mean rank value in the Friedman test for slice thickness variations of 0.6 mm is 3.70, 1 mm is 3.13, 1.5 mm is 1.85, and 2 mm is 1.32 so based on the test results, slice thickness variation that shows the most optimal anatomical information is 0.6 mm.

The modulation effect of ice thickness variations on convection in icy ocean worlds

ABSTRACT It has been long puzzling whether the ice thickness variations observed on Enceladus can be sustained solely by a polar-amplified bottom heating. The key to this question is to understand how the upward heat transport by convective plumes would be interfered by the temperature and salinity variations beneath the ice due to the ice thickness variations, which, however, has yet to be explored. Here, we find that the horizontal temperature variation induced by the ice topography can easily be orders of magnitude greater than the vertical temperature variation induced by bottom heating using scaling analysis. Due to the dominance of horizontal temperature gradient, convective plumes are completely shut off by a stratified layer under the thin ice formed out of baroclinic adjustment, largely slowing down the vertical tracer transport. The stratified layer will also deflect almost all of the core-generated heating towards the regions with thicker ice shell, destroying the ice thickness gradient. These results allow us to put an upper bound on the core-generated heating on Enceladus, which is crucial for the estimate of habitability. Scaling laws for the bottom heat flux to penetrate the stratification are derived and examined. This scaling can be used to constrain the maximum ice thickness variations induced by heterogeneous bottom heating on icy satellites in general, which can be used to differentiate icy satellites that generate the majority of heat in the ice shell from those that generate the majority of heat in the silicate core.

Effect of Slice Thickness Variation on Spatial Resolution of CT-Scan Device Images at the Bali Mandara Hospital Radiology Installation

Aims: Slice thickness variation analysis on spatial resolution on CT-scan images by determining CNR and SNR values, by making ROI on object and background images. ROI size of objects and backgrounds can be observed with several criteria based on the provisions of the ACR program, so that optimization of CT-Scan image quality can be achieved.&#x0D; Place and Duration of Study: The Radiology Installation in Bali Mandara Hospital, between 23 March to 20 May 2022.&#x0D; Methodology: Data collection begins with preparing the equipment used, namely CT-Scan, head holder, phantom, and computer. After that, the head holder is placed in the middle of the gantry and then the phantom is placed with the guidance of the laser beam (alignment system). Set the axial beam on the vertical line of section 1 and then set the coronal beam on the horizontal line of section 2. After that, setting the type of examination using the adult head protocol and setting the scan parameters to 80 kV, 100 mAs, and slice thicknesses 1, 2, 3, 4, 6, and 8 mm. After the preparation is done then the next exposure to the phantom. Then the research data in the form of phantom images will be seen as a whole to program on the computer monitor. Measurements were made 5 times for each slice thickness. Next is to analyze the CNR of digital phantom image data on a computer. So that it can be determined object ROI, background ROI, object mean, background mean, and standard deviation of the background.&#x0D; Results: The results showed that the thicker the Slice Thickness, the higher the CNR and SNR values. The highest CNR value occurred in air medium (13.70) and the lowest occurred in Nylon (0.86). Likewise, the highest SNR value occurred in air medium (13.84) and the lowest in Nylon (0.99). The highest CNR and SNR values ​​occurred in air medium and the lowest occurred in Nylon. &#x0D; Conclusion: Slice Thickness variations affect the spatial resolution of CT-Scan images as indicated by the CNR and SNR values however, the CNR and SNR values ​​are still above 1.0 for adult head examination and above 0.7 for children's head examination. So that the quality of CT-Scan images at Bali Mandara Hospital is still very good.

Impact of recombination mechanisms on the capacitance-voltage characteristics in bulk heterojunction organic solar cells

Low frequency Capacitance- voltage (C-V) measurements have been employed to investigate the effect of thickness variation of poly (3-hexylthiophene (P3HT) and fullerene [6,6],-phenyl-C61-butyric acid methyl ester(PCBM) based Bulk Heterojunction (BHJ) photo absorbing layer in inverted organic solar cell (OSC) configuration, ITO|ZnO|P3HT:PCBM|MoO3|Ag and are corelated with different recombination mechanisms. The normalized capacitance (CCgeom) with voltage curves at different P3HT: PCBM blend thicknesses such as 130, 100, 80 and 70 nm demonstrate an increase in peak height with thickness as well as the presence of negative capacitance (NC) beyond peak voltage for higher thicknesses. To understand both peak height variation and the occurrence of NC, a defect sensitive simulation study has been performed by employing the radiative and non-radiative recombination processes. Based on the analysis of simulation results we confirm the role of Langevin bimolecular recombination rate in determining the peak height with thickness; however, the presence of NC in C-V curves can be understood through a competition between the Langevin bimolecular, and trap assisted recombination rates. Study confirms that peak height reduces due to increase in the rate of Langevin bimolecular recombination, whilst the trap assisted recombination resurges the NC beyond peak voltage. Later, the utilities of D-D based1C23 vs V analysis to calculate built-in voltage (Vbi) have been performed for the experimental and simulation data at different thicknesses emphasizing the strength of this approach to characterize threshold voltage of organic diodes.

Effect of elastic foundation and porosity on buckling response of linearly varying functionally graded material plate

This work presents the buckling response of porous plate made of functionally graded materials (FGMs). A tapered FGM plate with uniaxial and biaxial loading under numerous boundary conditions was investigated. Simple power law and sigmoidal law are applied to compute the tailored material properties. Further, the effect of Pasternak foundation on the buckling response for a plate is computed, considering the five types of porosity pattern. The first order-shear deformation theory (FSDT) is used to describe the kinematic field of the plate. The variational principle is used to derive the equation of motions. Subsequently, the solution for buckling analysis is found by applying the Galerkin’s-Vlasov method. It has been seen that the effect of elastic foundation largely influenced the buckling response of FGM plate, especially Pasternak foundation has significant effect when comparing with Winkler’s foundation. Similarly, buckling load, subjected to uniaxial or biaxial compression of plate, decreases greatly for porous material. Numerical examples for computing buckling response are compared for accuracy and verification purpose of the present formulation, with earlier published results. Considering the effect of thickness variation, span ratio, compressive load conditions, foundation stiffness and porosity on buckling analysis are estimated and established as a benchmark result in tabulated form. Moreover, parametric studies have been done, by keeping in view, to explore the utility of FGM tapered plate and the responses represented in the graphically form.

Effect of Thickness Variation on the Measured Seebeck Coefficient and Power Factor in ITO–NiCr Thin‐Film Thermocouples

Herein, the electrical resistivity, Seebeck coefficient, and power factor of an indium tin oxide (ITO) and nickel‐chromium (NiCr) thermocouple are investigated. The thicknesses of the ITO and NiCr are varied between 10 and 430 nm. Seebeck coefficients between 12.8 and (21.4 ± 1.5) μV K−1 are measured, respectively. The results indicate that a reduction in thickness generally leads to an increase in the Seebeck coefficient until a maximum value is reached. Among the measured samples, the optimal Seebeck coefficients are found with an ITO thickness of (111 ± 4) nm and NiCr thickness of (18 ± 2) nm. Finally, the power factor of the thermocouples is determined, with a maximum power factor of (84 ± 7) μW m−1 K−2 for the ITO thickness of (111 ± 4) nm and nickel‐chromium thickness of (42 ± 5) nm.

Simulation of efficient Sn/Pb-based formamidinium perovskite solar cells with variation of electron transport layers

Numerical modelling on functional Sn-based perovskite solar cells (PSCs) has been performed and compared with Pb-based PSCs by using general-purpose photovoltaic device model software. The effect of variation in active layer thickness and various electron transport layers (ETLs), including tin oxide (SnO2), zinc oxide, C60, titanium dioxide, phenyl-C61- butyric acid methyl ester, on the photovoltaic parameters of Sn-based PSCs has been investigated. The active layer thickness was observed to be 500 nm, and SnO2 as ETL material resulted in the most efficient PSC. The optimized Sn-based device with formamidinium tin iodide as perovskite active layer shows promising results with a maximum power conversion efficiency of 24.41% compared to 27.49% for formamidinium lead iodide-based device. Further, other photovoltaic parameters for lead free PSC devices are quite comparable as for lead-based devices, showing the potential of Sn-based perovskite material as a fair candidate to replace toxic Pb-based-PSCs.