Thickness Profile Research Articles

A Model for Simulating the Upward Flow of a Viscous Fluid in a Fracture Network

Fluid migration in a fracture network plays an important role in the oil accumulation mechanism and hence is key to oil exploration. In this study, we build a model by combining one-dimensional (1D) Navier–Stokes equations, linear elastic equations, and energy equations, and validate the model by reproducing the thickness profile of a fluid-driven crack measured in an experiment. We employ this model to simulate the upward flow of viscous fluid in a single fracture during hydrocarbon migration. The simulation suggests that the parameters of both the fluid and the surrounding rock matrix, as well as the boundary condition imposed on the fracture outlet, affect the upward flow in the fracture. We then extend our model from the single fracture to the bifurcated fracture and the fracture network by maintaining homogeneous pressure and mass conservation at the connection of the channels. We find that the increase in network complexity leads to an increase in the inlet pressure gradient and inlet speed, and a decrease in the outlet pressure gradient and outlet speed. The effective area where the fluid is driven upward from the inlet to the outlet is offset toward the inlet. More importantly, the main novelty of our model is that it allows us to evaluate the effect of inconsistencies in individual branch parameters, such as matrix stiffness, permeability, temperature, and boundary conditions, on the overall upward flow of viscous fluid. Our results suggest that the heterogeneity enforces the greater impact on the closer branches.

Angular distribution of species in pulsed electron beam deposition of BaxSr1-xTiO3

The angular thickness and composition profiles of thin films obtained by irradiating a BaxSr1-xTiO3 (x = 0.2) target with a pulsed electron beam were investigated by Rutherford backscattering spectrometry for argon and oxygen background gases at a pressure of about 10-2 mbar. A “semi-sphere” holder was used, resulting in a fixed target to substrate distance of about 40 mm. The film thickness profiles have forward shaped peaks, with measurable thickness up to 80-90° for major axis and 25° for minor axis, and presents similar trend for both argon and oxygen background gas. The analysis of the congruent transfer of the elements from the target as a function of the angle showed that the film composition is not uniform over this wide angular range and differs with respect of the ablated target depending on the element used and on background gas.

REWORKED MESOZOIC RADIOLARIANS IN MIOCENE-PLIOCENE FORELAND SEDIMENTS IN THE ZAGROS BELT, IRAN

Micropaleontology can give important insights into the provenance and paleoenvironmental conditions in terrestrial sedimentary archives. For the current study, 84 samples representing a 2.6 km thick sedimentary profile from the SimplyFolded Zagros Mountain Belt were investigated. They span ca. 10.2 my from the late Middle Miocene (Serravallian) to the earliest Pleistocene (Gelasian), and comprised floodplain sediments and saline mudstones with an aeolian contribution. The mudstones revealed a unique Cretaceous radiolarian assemblage comprising largely of cryptothoracic Nassellarians and spherical spumellarians. This record highlights the reworking of sediments derived from Cretaceous Qulqula- Kermanshah radiolarian claystones and radiolarites in the Imbricated Zagros belt into the distal Neogene Zagros foreland sediments in Lurestan (Lurestan Arc). The high abundance of Holocryptocanium barbui (Dumitrica) and other cryptothoracic taxa compared to the Qulqula- Kermanshah radiolarian claystones and radiolarites potentially indicates a preferred erosion of softer units such as the Red Radiolarian Claystone Unit (RRCU) compared to harder radiolarian cherts. The observation of a reworked largely cryptothoracic assemblage might also point to additional sorting effects during fluvial and aeolian transport as well as during redeposition, depending on the morphology and hydrodynamic properties of individual radiolarian taxa.

Impact of multifocal gas-permeable lens designs on short-term choroidal response, axial length, and retinal defocus profile.

To investigate the impact of multifocal gas permeable contact lens (MFGPCL) in various add power and distance/near area allocation on short-term changes of choroidal thickness (ChT), axial length (AL), and retinal defocus profile in young adults. Seventeen young adults (2 males and 15 females; age 23.17±4.48y) were randomly assigned to wear two designs binocularly with a one-week washout period in between. Total of four MFGPCL designs were assessed. All designs were distance-center that varied in two add power (+1.50 and 3.00 D) and/or two distance zone (DZ) diameters (1.50 and 3.00 mm; design A: DZ 1.5/add 3.0, B: DZ 1.5/add 1.5, C: DZ 3.0/add 3.0, D: DZ 3.0/add 1.5). ChT, AL, and peripheral refraction data were collected on each subject at baseline, on days 1 and 7 of MFGPCL daily wear. ChT was assessed in four quadrants using a spectral-domain optical coherence tomography. AL was shortened by -26±44 µm with lens C, -18±27 µm with lens D, -13±29 µm with lens A, and -8±30 µm with lens B (all P<0.05). A significant overall increase in ChT was observed with all 4 designs (lens A: +6±6 µm, B: +3±7 µm, C: +8±7 µm, and D: +8±7 µm). Temporal and superior choroid exhibited more choroidal thickening associated with MFGPCL. All designs induced significant relative peripheral myopia (RPM) beyond the central 20° across the horizontal meridian in both nasal and temporal fields (P<0.05). MFGPCLs show a significant influence on ChT and AL, which are associated with significant increase in RPM after short-term wear. The reliability and feasibility of quantifying short-term changes in ChT support its use as a promising marker for the long-term efficacy of myopia-controlling treatments.

Vibration characteristics of multilayer functionally graded microplates with variable thickness reinforced by graphene platelets resting on the viscoelastic medium under thermal effects

Due to their improved mechanical properties and adaptability, microplates with tailored variable thickness profiles are becoming essential parts of advanced micro- and nanoelectromechanical systems (MEMS and NEMS). This study conducts a thorough analytical analysis of the vibration properties of thermally loaded, multilayer functionally graded graphene platelet-reinforced composite (FG-GPLRC) microplates of linearly or parabolically varying thickness resting on viscoelastic medium under different boundary conditions. The Halpin–Tsai micromechanical model and the law of mixtures are employed to calculate the effective material characteristics for various reinforcement distributions in the microplate. These distributions encompass uniformly symmetric and asymmetric arrangements. The study utilized the first-order shear deformation theory (FSDT) in conjunction with the modified strain gradient theory (MSGT) and Hamilton's principle to generate the dynamic governing equations for the structure, accounting for size-dependent effects. The resulting equations are afterwards solved using the utilization of the Galerkin technique. This enables the evaluation of the proposed solution's correctness and precision. The impact of various factors on vibration behavior is investigated through numerical analysis. These factors encompass length scale parameters, temperature fluctuations, temperature distribution profiles, boundary conditions, the distribution pattern of the GPL, taper constants in both unidirectional and bidirectional scenarios, the weight fraction of the GPL.

New Generation of Small Incision Lenticule Extraction (SMILE) Procedure for Myopic Astigmatism with High Astigmatism Value : A Case Series

Introduction : Myopic astigmatism is a refractive disorder which could cause visual impairment especially with high astigmatism value. It affects patients’ productivity and quality of life. The management for myopic astigmatism is challenging because no consensus on the ideal method was reached.&#x0D; Case Illustration : Case 1: 19-year-old male with Uncorrected Visual Acuity (UCVA) 3/60 in the right eye with a manifest refraction of S-3.25 C-2.00 x 0 and 2/60 in the left eye with a manifest refraction S-5.50 C-0.50 x 0. Case 2: 18-year-old male with UCVA 3/60 in both eyes with a manifest refraction of S-3.00 C-2.25 x 5 and S-2.50 C-2.00 x 0. Case 3: 18-year-old male with UCVA 3/60 in both eyes witha manifest refraction of S-2.75 C-2.00 x 0 and S-2.50 C-2.25 x 180. Slit lamp, fundus examination, corneal topography, tomography, epithelial thickness profile, and aberrometry were within normal limits. The patients underwent SMILE using Visumax 800 Femtosecond laser with 3-4 mm incision at 120°, optical zone between 6-6.8 mm and cap thickness between 100-120 ?m.&#x0D; Discussion : In this case series, SMILE was chosen because studies described SMILE as an effective and safe refractive procedure compared to Femtosecond Laser-assisted in situ keratomileusis (FS-LASIK). Target refraction is emmetropia without cyclotorsion adjustment, it showed that post operative UCVA in all eyes were 6/6 using Snellen chart and none of the eyes loss the BCVA.&#x0D; Conclusion : New Generation of SMILE as management of myopic astigmatism with high astigmatism value shows good result improving visual outcomes.

24. CRITICAL IMPORTANCE OF NOZZLE TEMPERATURE TO BIOPRINT VASCULAR GRAFTS WITH SHEAR-THINNING HYDROGEL

Abstract Introduction The development of vascular grafts adapted to the nature of the patient and their treatment is constantly evolving. Fine control of the bioprinting manufacturing process is a key issue to obtain proper personalized vascular grafts. The aim is to check the influence of the nozzle temperature during bioprinting a Gelatin/Gellan Gum/Alginate hydrogel vascular grafts. Methods Vascular grafts were printed using a Gelatin/Gellan Gum/Alginate (8:3:0.5 %w/v) hydrogel in an BioX bioprinter with the printhead and bed set up to 65 °C. Two configurations were set: 1) a standard conical tip (nozzle) and 2) the same nozzle thermally insulated with aluminum foil to uniformly distribute the temperature. A temperature control using a 100 kΩ thermistor was performed in four points: chamber, nozzle, printhead, and bed. Four heating/cooling cycles were performed in each control point. Results The grafts printed with the standard nozzle exhibited irregular wall thickness and an uneven surface, attributed to lower temperatures in the conical tip. In contrast, results from the aluminum-covered nozzle indicated temperature distributions of 33.13±0.87, 49.03±3.92, 52.38±3.53, and 64.98±0.10 °C for chamber, nozzle, printhead, and bed, respectively. This improved temperature distribution enhanced the printability of Gelatin/Gellan Gum/Alginate vascular grafts, resulting in a more regular wall thickness and surface profile. Conclusion The optimization of temperature in the nozzle during the printing process is a critical parameter for bioprinting vascular grafts using this shear-thinning Gelatin/Gellan Gum/Alginate hydrogel.

Study of the wall pressure variations on the stall inception of a thick cambered profile at high Reynolds number

Study of the wall pressure variations on the stall inception of a thick cambered profile at high Reynolds number

Choroidal measurements in decision making for retinopathy of prematurity: a decision tree analysis

BackgroundTo compare the choroidal thickness and vascular profile of premature infants with ROP (retinopathy of prematurity) using a handheld SD-OCT device.MethodsWe performed horizontal SD-OCT scans through the fovea in 115 eyes of 66 premature infants. Premature infants included 2 groups [infants with ROP requiring treatment (as treatment group) vs. infants without ROP or with ROP not- requiring treatment (as no-treatment group)] Choroidal thicknesses (CT) were measured at 5 points, including the fovea, 250 µm, and 500 µm mm nasal and temporal to the fovea. The choroidal vascularity index (CVI) and choroidal stromal index (CSI) were also calculated. The classification and regression tree (CRT) algorithm was used to predict the need for treatment based on all OCT characteristics.ResultsMean CT was higher in 500 µm nasal to the fovea compared to temporal CT (275.8 ± 64.8 and 257.1 ± 57.07, P value < 0.03). No statistically significant difference was found regarding CVI, corrected CVI, and temporal and nasal CT in the treatment group versus the no-treatment group. The foveal CT was significantly lower in ROP patients with the plus disease compared to not-plus ROP (P value = 0.03. ANOVA, Bonferroni posthoc test). CT was not significantly different between plus and pre-plus patients (P-value = 0.9, ANOVA, Bonferroni posthoc test). No significant relationship was found between the stage of ROP and choroidal thickness (P value > 0.05, GEE). The decision tree analysis showed that in infants with ROP, the most important predictor for the need for treatment is CSI.ConclusionThis study delineated the possible effectiveness of choroidal measurements as an additive to decision-making for ROP. We also demonstrated that choroidal involution is associated with the presence of plus disease, not with the stage of ROP. We demonstrated that choroidal measurements are very sensitive but not specific tools for assessing the need for treatment in ROP patients.

Flat and bent branes in Born–Infeld-like scalar field models

In this work, we investigate the presence of thick branes modeled by a single scalar field with Born–Infeld-like dynamics. We consider the 4-dimensional metric being Minkowski, de Sitter or anti-de Sitter. We obtain the field equations and the conditions to get a first order formalism compatible with them. To illustrate our procedure, some specific models are presented. They support localized warp factor and have their properties controlled by the 4-dimensional cosmological constant. In particular, a hybrid brane may arise, with a thick or thin profile depending on the extra dimension being inside or outside a compact space.

New Insights into the Molecular Structure of Tear Film Lipids Revealed by Surface X-ray Scattering.

The tear film lipid layer (TFLL) is a unique biological membrane that serves a pivotal role in the maintenance of ocular surface health. Reaching an overarching understanding of the functional principle of the TFLL has been hampered by a lack of insights into the structural and functional roles played by individual lipid classes. To bridge this knowledge gap, we herein focus on studying films formed by principal lipid classes by surface scattering methods. Through grazing incidence X-ray diffraction and X-ray reflectivity studies, we reveal quantitative data about the lattice distances, molecular tilt angles, and mono/multilayer thickness and density profiles for central TFLL lipid classes under close to simulated physiological conditions. In addition, we discuss the correlation of the results to those obtained previously with the natural lipid composition of meibum.

How emulsified droplets induce the bursting of suspended films of liquid mixtures.

Emulsion droplets of silicone oil (PDMS) are widely used as antifoaming agents but, in the case of non-aqueous foams, the mechanisms responsible for the bursting of the films separating the bubbles remain unclear. We consider a ternary non-aqueous liquid mixture in which PDMS-rich microdroplets are formed by spontaneous emulsification. In order to quantitatively assess the effect of the emulsified microdroplets, we measure the lifetime of sub-micrometer-thick suspended films of these emulsions as well as the time variations of their thickness profiles. We observe that a droplet entering the film reduces its lifetime by inducing a local and fast thinning. In most cases, we ascribe it to the spreading of the drop at one of the film interfaces with air, which drags the underlying liquid and eventually causes the film to burst rapidly. We explain why, despite slower spreading, more viscous droplets cause films to burst more efficiently. More rarely, microdroplets may bridge the two interfaces of the film, resulting in an even more efficient bursting of the film, which we explain.

Preparation and evaluation of Oral Thin Film of Eugenol for tooth decay

Preparation and evaluation of Oral Thin Film of Eugenol for tooth decay

Corneal and epithelial thickness mapping in diabetic patients using optical coherence tomography

Purpose To evaluate corneal and epithelial thickness using the anterior segment optical coherence tomography and to correlate these changes with major disease parameters, that is duration of the disease, status of control (glycated hemoglobin level), and stage of diabetic retinopathy. Patients and methods Corneal and epithelial thickness profile of 25 patients diagnosed with diabetes mellitus and 25 healthy individuals were measured by anterior segment optical coherence tomography. Full ophthalmological examination of all patients was done. The disease duration and the glycated hemoglobin levels were recorded. Results In diabetic patients, there was nonsignificant thinning in mean central epithelial thickness (P=0.14). The mean central corneal thickness is slightly thicker, however, it did not reach significance (P=0.051). There was statistically significant thickening in central stromal thickness (P=0.015). There was a significant negative correlation between the severity of retinopathy and superior epithelial thickness (P=0.037). The duration of the disease showed significant correlation with most of epithelial thickness values, however, HA1c level was not found to have any statistically significant effect on corneal and epithelial parameters. Conclusion Chronic metabolic stress of diabetes has an impact on corneal epithelium and stroma. Severity of diabetic retinopathy should be considered as a risk factor during corneal surgeries to avoid epithelial and stromal-associated complications.

Constrained Vapor Bubble Experiment (CVB) in the Light Microscopy Module (LMM)

Abstract This short article describes the major findings from the CVB experiment performed in the LMM on the International Space Station from 2010–2012. CVB was the first experiment to run in the new facility and focused on understanding the heat transfer and fluid mechanics occurring inside a wickless miniature heat pipe. The LMM was used to map the location of the vapor-liquid interface inside the device and to measure the film thickness profile on the walls of the device. Several interesting and unexpected phenomena were observed in microgravity including flooding of the heater end with liquid as the heat input increased, explosive nucleation of vapor bubbles at the heater end in the shortest version of the heat pipe tested, condensation on highly superheated surfaces, and the spontaneous formation of rip currents as the device tried to enhance the contact line area available for evaporation of the liquid.

Assessment of Corneal Cross-Linking Effect on Progressive Keratoconus by Using the ABCD Grading System.

The aim of this study was to assess changes in corneal parameters 6 months after corneal cross-linking for progressive keratoconus, using the ABCD system. This retrospective study was conducted at the King Khaled Eye Specialist Hospital (Riyadh, Saudi Arabia) between January 1 and July 30, 2022. This study included 16 eyes of 16 patients with keratoconus who underwent corneal cross-linking at the same hospital and were at least 18 years old. At least one preoperative (T0) and one postoperative examination was performed for each patient. Six months after the procedure (T1), patients underwent corneal tomography. The parameters A, B, C, and D were also evaluated. Other parameters monitored included maximal keratometry (Kmax) (K1 and K2), Belin/Ambrósio Enhanced Ectasia Display, and index vertical asymmetry. The progression of ectasia was identified by a consistent change in at least two parameters: steepening of the anterior corneal surface or the posterior corneal surface, thinning or an increase in the rate at which the corneal thickness changed from the periphery to the thinnest point, where the magnitude of the change was greater than the normal noise of the testing system. Among the patients, 68.8% were men. The patients' average age was 25.8±5 years. Throughout the 6-month postoperative follow-up, parameters A, B, and C exhibited substantial changes (P = 0.000 for parameters A, B, and C). Parameter A increased 6 months after surgery, whereas parameters B and C decreased. Preoperatively and 6 months after surgery, Kmax, K1, and Belin/Ambrosio-enhanced ectasia demonstrated substantial differences. However, parameter D, K2, and the average pachymetric progression index did not change significantly. Anterior and posterior corneal curvatures and corneal thickness profiles can be useful for monitoring the progression of keratoconus and the success of the corneal cross-linking operation.

Uniformity of Electrodeposited Coatings Onto Additively Manufactured Graphite Lattice Electrodes

The ability to uniformly electrodeposit metallic coatings onto geometrically complex substrates plays a significant role in developing specialized applications from coating detailed RF components to depositing catalytic coatings onto ordered foams electrodes for electrochemical flow reactors. However, there presently lacks guidelines for electrodeposition in porous media due to the problem’s multi-scale complexity. We present a framework for deconvoluting this process through continuum-level modeling and experimental validation of electrodeposited copper onto additively manufactured conductive lattice structures. Through numerical simulations we can predict thickness profiles and validate the model prediction and coating quality through micro-computed tomography. We further devise scaling laws with the aim of facilitating control over deposition uniformities on different lattice architectures and dimensions under fluid flow. In extension, the manufacturing platform for functionalized electrodes is extended to battery applications as use in novel electrode geometries within rechargeable secondary batteries as well as plating thickness evolution in custom redox flow battery cathodes for grid scale energy storage.This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 within the LDRD program 20-ERD-056. LLNL-ABS-847849.

On the use of double‐double design philosophy in the redesign of composite fuselage barrel frame components

AbstractThe use of optimization procedures can provide a valuable contribution in optimizing the laminate design of composite components for mass minimization and mechanical performance maximization. Design for weight and strength requirements of composite structures can be efficiently provided with the newly developed double‐double laminates concept, which allows to overcome the conventional 0, 90, and ±45° ply orientations and symmetry requirements in laminates. In the double‐double designed components, composite laminates are made up stacking thin sub‐laminates with four [±Φ, ±Ψ] oriented plies without symmetry requirements. In the present paper, the lay‐up and thickness profile of the composite frames in a fuselage section have been redesigned according to the double‐double design concept taking into account the operating loads. The starting quad configuration has been replaced by an optimized double‐double configuration with suitable lay‐up and thickness profile for each of the frames, while achieving a reduction in the total components mass.Highlights Double‐double laminates offer a novel approach to composite laminate design. Double‐doubles aim to simplify design with composites as with metals. Laminate optimization performed varying plies orientations and number. Double‐double design of components optimized with respect to the acting loads. In aviation double‐doubles allow lightening of composite laminate components.

Influence of La3+-Co2+ substitution on X-band microwave absorption properties of Ba0.5Sr0.5Fe12O19 nanoparticles with insight into quarter wavelength phenomenon

The presented study aims to tune the microwave absorption properties by varying the chemical composition of Ba0.5Sr0.5Fe12O19 nanoparticles with Co–La substitution via the synthesis route of the sol-gel citrate precursor method. X-ray diffractograms (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR) confirmed the formation of pure phase M-type hexagonal ferrite with varying lattice parameters. The permittivity measurements revealed increased dielectric losses, indicating good energy dissipation behavior. Enhancement of magnetic behavior resulted from the strengthened exchange interactions between lattice sites, leading to higher permeability values. Significant reflection losses were exhibited by our synthesized samples with a maximum reflection loss of −42.08 dB at 4.62 GHz for x = 0.35 at an experimental thickness of 3 mm. The dependence of reflection loss peaks on matching thickness was analyzed using calculated thickness profiles, revealing their close agreement with simulated thickness. The study highlighted the potential of synthesized samples for electromagnetic signature reduction, in both commercial and military applications.

Application of a Three‐Dimensional Coupled Hydrodynamic‐Ice Model to Assess Spatiotemporal Variations in Ice Cover and Underlying Mechanisms in Lake Nam Co, Tibetan Plateau, 2007–2017

AbstractA three‐dimensional lake‐ice coupled model is used to investigate the space‐time variations of ice and underlying mechanisms in Lake Nam Co (LNC), the third largest lake over Tibetan Plateau (TP), during 2007–2017. The model reasonably reproduces the in situ measured ice thickness and water temperature profile, and satellite retrieved ice coverage and lake surface temperature. Seasonally, the lake ice first forms in the eastern basin during early January, expands from east to west during January and February, covers nearly the entire LNC in March, starts melting from west to east in April, and eventually disappears in May. The eastward drift of thin ice throughout the ice‐covered phase and the eastward water heat transport during the ice melting phase are key factors to determine the spatial variation of ice and freeze‐thaw processes. A multiple linear regression analysis confirms that the eastward drift of thin ice can be mostly attributed to the prevailing westerly. During 2007–2017, ice volume, duration, ice‐on and ice‐off dates show significant interannual variations, and they are highly correlated with the surface air temperature (T2m) averaged over January‐March, from the preceding December to May, in December and over March–May, respectively, suggesting the “cumulative effects” of T2m. Seasonal and interannual variations of ice drift are attributed to the combined effects of wind and ice volume variations. Sensitivity analysis further points out the important impacts of ice on the lake temperature and circulation structure in winter and spring, hence the necessity of hydrodynamic‐ice coupled models in large TP lakes.