Terms Of Penetration Depth Research Articles

Stoneley waves in isotropic crustal rocks under the theory of generalized thermoelastic diffusion

This paper investigates the propagation of Stoneley waves through bonded and unbonded interfaces between two dissimilar homogeneous transversely isotropic generalized thermo-elastic diffusion rocks. The governing equations for the current problem are obtained and are solved to determine the characteristic polynomial equations for both mediums in terms of penetration depth. These equations are solved using Ferrari’s approach, and the variation in penetration depths with angular frequency and wavenumber is shown. The secular equations of the Stoneley waves are developed using proper boundary conditions and these equations have been solved numerically to determine the phase velocity and attenuation coefficients. We have discovered three modes of the Stoneley waves in thermo-diffusive crustal rocks. We have confirmed that the paths of particle motion for Stoneley waves are elliptic in nature. Some known results [Kumar et al. [2017] “Mathematical modeling of Stoneley wave in a transversely isotropic thermoelastic media”, Applications and Applied Mathematics 12(1), 319–336; Kumar and Kansal [2008b] “Propagation of Rayleigh waves on free surface of transversely isotropic generalized thermoelastic diffusion”, Applied Mathematics and Mechanics29(11), 1451–1462] are recovered from this analysis to validate our investigation.

Using Fundamental Parameters and Artificial Neural Network for Controlling the Laser Welding of Metals

The present work aims to design an artificial neural network (ANN) for controlling the geometry of the fusion zone in different welding conditions. AA5754 aluminium plates with 6 mm thickness were welded in butt configuration by using an Yb-doped fiber laser in continuous wave regime. Laser power, travel speed, beam diameter and shielding gas were considered as process-related factors, while the weld geometry was evaluated in terms of penetration depth and bead width. The accuracy of the model was endorsed by using untrained test data. Results showed a good agreement between the ANN output and the experimental values.

Combining protective clothes with human body models for finite element ballistic impact simulations

The ballistic deformation of an ultra-high-molecular-weight (UHMW) polyethylene (PE) composite has been subjected numerically to a multi-layered soft ballistic fabric package modelled upon the body contours of the Global Human Body Models Consortium (GHBMC) human body models M50-P and F05-P. The results of the clothing-body-interaction have been investigated and compared to the behavior of anthropomorphic surrogate models made from ballistic clay. For building the fabric model in donned shape, a single ply of woven fabric material has been converted upon the anthropomorphic body contour by subjecting it to a quasi-deep drawing process. After the fabric deformation, the shaped layer was duplicated 20 times and shifted outwards to build the fabric model, representing a multi-layered soft ballistic fabric package. The results of the ballistic impact simulation show that the response of the human body models (HBMs) is much more compliant than the behavior of the surrogate models. The deformation of the female HBM in terms of penetration depth and diameter of the affected impact region is slightly more severe than the deformation of the male counterpart with respect to identical impact conditions.

Discussion on Static Resistance of Granite under Penetration.

A total of 9 tests were carried out with 30 mm and 78 mm caliber scaled projectiles penetrating into granite targets. The penetration depth, crater diameter, and mass loss rate were examined and discussed. The results indicate that the dimensionless penetration depth of large-caliber projectiles is 20% greater than small-caliber projectiles. Based on the description of static resistance Ra in the Forrestal semi-empirical formula, the size effect of dimensionless penetration depth can be attributed to the size effect of static resistance Ra, and it can be seen that the penetration static resistance of projectile A is 40% higher than that of projectile B. Numerical simulations of projectile penetration into granite targets were conducted using the finite element program ANSYS/LS-DYNA. In terms of penetration depth and crater damage, the numerical simulation results agree well with the test data. This suggests that the selection of parameters was reasonable. The influence of compressive strength, projectile striking velocity, mass, diameter, and caliber-radius-head (CRH) ratio on the static resistance Ra were studied by RHT model parameterization. Based on the numerical results from the parametric study, an empirical formula was derived to predict the static resistance Ra.

INVESTIGATION OF THE IMPACT OF A POROUS TUNGSTEN IMPACTOR WITH A COMBINED BARRIER

With high-speed penetration (with velocities more than 2000 m/s), the length of the cavity from a porous striker is greater than from a striker of monolithic (solid) material equal to it in size and density. But at the same time the cavern is narrower, so the volumes of the caverns are almost the same. The process of length reduction and penetration of the strikers (porous and monolithic) for a long time occurs almost identically and only at the last stage of penetration and, especially in the aftereffect phase (after the complete destruction of the striker), there is a difference. This is explained by the fact that during the movement of the porous striker, due to the collapse of the pores, an increase in density occurs, so that the density of the porous striker becomes greater than the density of the solid striker. Then, in the case of a limited thickness of the barrier, the advantage of a porous striker in terms of penetration depth may simply not have time to manifest itself. The results of experiments conducted to confirm this assumption are presented below. The results of experiments on the collision of a porous tungsten impactor with a combined barrier consisting of a steel and polyethylene plate are presented, and the results are analyzed. The problem of numerical simulation of the above experiment by a mesh-free Lagrangian continuous medium modeling method is solved. The calculation model, the results of numerical modeling and a comparative analysis of the results of the experiment and numerical modeling are presented. At the penetration rate V ? 1920 m/s, the porous striker is 2.8% less destroyed when a strong steel barrier is broken through, but in a low-strength polyethylene barrier, the length reduction coefficient of the porous striker is 170% higher relative to the steel one. In addition, a steel striker after breaking through an obstacle (in the air) it does not collapse, unlike porous, which may also be a consequence of the low strength of the latter.

Shock wave enhanced emission photoacoustic streaming (SWEEPS): An alternative to conventional irrigation in endodontic treatment

Background: Irrigation is an essential step in root canal treatment (RCT). However, the complex structure of the root canal can limit the penetration of irrigants, causing RCT failure. Shock wave enhanced emission of photoacoustic streaming (SWEEPS) has been developed to improve root canal cleaning by increasing the penetration of irrigants. SWEEPS utilized the Er:YAG laser to generate micropulse, producing bubbles delivered in liquid, causing powerful photodynamic streaming. However, its superiority compared to conventional irrigation remains unclear. Thus, we aim to review the available evidence to assess the benefits of SWEEPS over conventional irrigation. Purpose: This study aims to review the available evidence to assess the benefits of SWEEPS over conventional irrigation. Reviewa: Article searches were conducted on Pubmed, ScienceDirect, EBSCOhost, and ProQuest using SWEEPS and root canal irrigation as keywords. Articles were included if they aim to assess the benefits of SWEEPS over conventional irrigation in removing smear layer, debris, pulp tissues, or bacteria. A total of 833 articles were initially retrieved from systemic search of literature and 6 articles following inclusion criteria were included in the review. Out of 6 articles, 4 articles suggested that SWEEPS could increase the removal of smear layer, debris, pulp tissues, and bacteria in the root canal compared to conventional irrigation. However, 2 articles found contradictory results, in which SWEEPS and conventional irrigation had similar outcomes in terms of penetration depth and could not completely eradicate biofilm. Conclusion: This review suggests that SWEEPS offers more benefits over conventional irrigation since it can improve the removal of smear layer, debris, pulp tissues, and bacteria in the root canal.

Design and development of a double spiral antenna with an artificial magnetic conductor structure for hyperthermia treatment

A double spiral antenna with an artificial magnetic conductor (AMC) is designed, fabricated, and experimentally tested for hyperthermia treatment as a microwave power radiator. The proposed double spiral antenna has a compact structure, designed on an FR4 substrate with a thickness of 1.6 mm, and the dimensions of the proposed antenna is 32 × 32 × 3.27 mm3. The width and space between the spiral arms is 1.54 and inner and outer radius of the spiral is arm 1 and 12.82 mm. The antenna is fed by aperture feeding having dimensions of 16 × 14 mm2 that enhances the antenna's bandwidth. Further, an AMC unit cell (as a reflector) is designed to enhance the proposed antenna's performance, which is designed on an FR4 substrate with a size of 16 × 16 × 1.6 mm3. The size of an AMC structure is optimized to 64 × 64 mm2, consisting of 4 × 4 unit cells and placed at a 5 mm distance at the backside of a double spiral antenna, which enhances the directivity, and gain of the proposed antenna and also converges backfield in the forward direction. At a 5 mm distance, the AMC structure behaves as a reflector and converges all back field radiation in the required direction to make a directional radiation pattern which enhances the antenna's bandwidth and gain. The proposed applicator (antenna + AMC structure) is simulated with a heterogeneous phantom (112 × 112 × 86 mm3), and the performance of the applicator is evaluated by using a specific absorption rate (SAR) in terms of penetration depth (PD) and effective field size (EFS) inside the phantom. The PD and EFS are improved when an AMC structure is placed at the backside of the antenna. Further, the proposed applicator is analyzed for the regular shape of the tumor inserted in the phantom, with the tumor size as 20 × 20 × 10 mm3, located at 10 mm distance from the skin surface. The study of temperature distribution inside the phantom is also done when 2.5 W of power is applied to the applicator in a simulation environment, a temperature rise of the tumor that between the range of 41–45°C is observed, allowing the proposed antenna with an AMC structure to be a good choice for the hyperthermia treatment.

How Does Surgical Technique Affect Fluid Permeability? A Laboratory Study Comparing Nanofracture, Microfracture and Fine Wire Drilling Approaches

Category: Basic Sciences/Biologics; Ankle; Arthroscopy; Sports Introduction/Purpose: Current surgical practice for the treatment of osteochondral lesions in the ankle involves using one of three techniques to promote blood flow from subchondral bone tissue to the defect site, improving the rate of healing. These different techniques: - fine-wire drilling, nanofracture and microfracture, involve disrupting the trabecular bone. However, the size and method of these techniques means this varies in terms of penetration depth and diameter. Additionally, each technique causes differing degrees of damage to the trabecular structure, and the ability of fluid to flow through the porous structure. The aim of this study was to compare the influence of the different techniques on the fluid permeability of the tissue following by assessing the flow of radiopaque contrast agent using μCT image analysis. Methods: Fresh-frozen cadaveric tali specimens (n=12) were prepared through creating a 10mm diameter chondral defect in three different regions of each talus. Each region then underwent one of three surgical techniques: 1) Fine wire drilling, 2) Nanofracture or 3) Microfracture, undertaken by a single surgeon.0.1 ml radiopaque contrast agent (OmnipaqueTM 300) was then added to each region and imaged using a clinical μCT scanner (SCANCO Medical AG, 73.6 μm resolution) The amount of contrast agent that permeated through each different region was assessed through imaging processing. Results: The μCT analysis indicated that across the 12 samples, eight nanofracture regions demonstrated flow of contrast agent to the depth of the fracture site or deeper. Some lateral flow was also observed in these sites. Eight microfracture regions demonstrated that the flow of contrast agent was localised to the fracture site and a preferential flow laterally. In only one sample, did a fine wire drilling region demonstrate any fluid flow. In this sample, contrast agent had permeated through the drilling site to the bottom and some sub-site permeation was observed. However, in all samples that showed no permeation of contrast agent through the fracture site, there was a layer of contrast agent on the chondral surface or minor permeation through to the sub- chondral surface. Conclusion: Nanofracture showed improved fluid permeability throughout the surrounding trabecular structure, when compared to microfracture and fine wire drilling. Microfracture appears to allow some fluid flow, but this is confined to the immediate area around the fracture site, while fine wire drilling appears to allow almost no fluid flow through the surrounding trabecular tissue. This conclusion is reinforced by previous literature that concluded the damage to the structure of the trabecular tissue is reduced when using nanofracture, compared to the other two techniques.

Compact Dual-Band Zig Zag Shaped Implantable Antenna for Biomedical Devices

This paper presents a highly compact volume 12 mm3 Zig Zag-shaped implantable antenna for biomedical applications. The antenna performance is closely analyzed in terms of penetration depth, different human tissues, substrate materials, reflection coefficient, Impedance Bandwidth, directive gain, and SAR values. The three different models are analyzed for different resonating frequencies. It is found that the proposed antenna shows dual ISM bands (900 MHz to 970 MHz 2.36GHz to 2.49 GHz) with impedance bandwidth of 7.77 % and 5.5% respectively. The proposed implantable antenna is successfully fabricated and tested in skin mimicking gel (vitro model). The performance of the proposed antenna is enhanced by using a sorting pin and slots that provides dual ISM bands, an acceptable SAR of 856.3 W/KG, and a directive gain of -28.68 dBi. Parametric analysis of the proposed implantable antenna has been studied in detail. Simulated and fabricated results are compared and found almost similar

Effect of obturation technique on penetration of calcium silicate-based sealer into dentinal tubules after endodontic retreatment of mandibular premolars.

Confocal laser scanning microscopy (CLSM) was used to investigate the penetration of endodontic sealers into the dentinal tubules after retreatment using two different obturation techniques. Thirty mandibular premolars were prepared up to instrument F3 (ProTaper Universal, Dentsply) and filled with Endofill using the single cone technique. The canals were retreated using Mtwo instruments. Reobturation was performed with the Bio-C sealer mixed with a fluorophore dye (Fluo-3) using either the lateral condensation technique (group LC) or the single cone technique (group SC) (n = 15). Teeth were sectioned 2, 4, and 6mm from the apex and analyzed with CLSM to assess the penetration of the sealer into the canal perimeter and the maximum depth of penetration of the sealer into the dentinal tubules. Data were analyzed using ANOVA and the Student-t and Holm-Sidak tests. In the apical segment, the penetrated perimeter was significantly higher in the LC group than in the SC group (p < 0.05); no significant difference was found in the middle and cervical segments (p > 0.05). In terms of penetration depth, no significant differences were found for any of the segments studied (p > 0.05). The LC technique promoted a higher percentage of canal circumference penetrated by the sealer than the SC technique in the apical segment after endodontic retreatment. CLSM demonstrated that the LC technique promoted a higher percentage of canal perimeter penetrated by the Bio-C sealer than the SC technique in the apical segment of mandibular premolars after retreatment.

Effect of fragment impact on shaped charge jet formation and penetration into steel target

Purpose This paper aims to investigate the effects of fragment impacts to shaped charge warheads in terms of shaped charge jet formation geometries and penetration performances. Design/methodology/approach In experimental process, a fragment was accelerated to a shaped charge warhead by means of a powder gun to a velocity more than 1,000 m/s, and this impact led to conical damage in the explosive of the warhead. Deformation on the warhead was visualized using X-ray technique to observe holes generated during fragment impact. Penetration test was performed against AISI 1040 steel plates with the damaged shaped charge warhead. Penetration performance of shaped charge jet, which deviated from the symmetry axis, was simulated by using SPEED software with 3-D Eulerian method to validate the numerical modelling method by comparing penetration test and simulation results of damaged warhead. Findings Simulation and test results showed good correlation for the warhead in terms of penetration depth and hole geometry at the impact surface of steel plates. In addition, the effects of the numbers and the geometries of fragment holes on shaped charge jet penetration performances were investigated with validated numerical methods. Simulation results showed that the increase in the number of fragment holes in the explosive of the warhead led to particulation of shaped charge jet that diminished penetration depth in the target plate. Additionally, simulation results also showed that the fragment hole geometry in the explosive after different fragment impact angles affected the amount of jet deviation from the symmetry axis as well as penetration depth in the target plate. Practical implications The results obtained from the current study revealed that fragment impact angle and different number of fragment impact reduced the penetration performance of shaped charge warhead by influencing the symmetry of shaped charge jet negatively. Originality/value The current study fulfils the need to investigate how fragment impact on the shaped charge warhead affect the formation symmetry of shaped charge jet as well as penetration performance by experimental and numerical methods. Penetration performance result of asymmetric jet is compared by experimental and numerical studies. A detailed methodology on numerically modelling of the effect of fragment impact angle and number of fragment impact on shaped charge jet performance is given in this study.

Real-Time, Multicolor Fluorescence Imaging of Tumors in Tissues

Novel synthetic fluorescent dyes in combination with shortwave infrared irradiation allow the high-resolution imaging of tissues within living organisms and can overcome several limitations of existing techniques in terms of penetration depth. Furthermore, they enable the simultaneous visualization of multiple tissue types and processes, making it possible to distinguish tumors from surrounding tissues.

Numerical Simulation on Jet Forming and Penetration Performance of Several Amorphous Energetic Alloy Liner with Typical Structures

The structure and material of the liner are the key factors that affect the forming and penetration ability of the jet. In order to study the influence of new energetic materials and typical liner shapes on jet forming and penetration behavior, this paper takes ZrCuNiAlAg amorphous alloy as the liner material and establishes four shaped charge (SC) models with conical, sub-hemispherical, eccentric sub-hemispherical and hypercumulative liners respectively. The jet forming law and its penetration process against the concrete target plates under different liner shapes are studied based on the AUTODYN numerical simulation software. The results show that a stable jet can be formed from ZrCuNiAlAg amorphous alloy liner under the Mohaupt effect, but the jets produced by liners with different structures differs quite a lot. Under the same conditions including charge diameter, charge length diameter ratio and wall thickness, the tip velocity, the tip-tail velocity difference and the length of the jet formed by conical and hypercumulative liners are significantly higher than those of sub-hemispherical and eccentric sub-hemispherical liners. The jet length of the hypercumulative liner is the longest while that of the eccentric sub-hemispherical liner is the shortest. The hypercumulative jet can penetrate a concrete target plate with 400mm thickness at 250μs, and the jets formed by conical, sub-hemispherical and eccentric sub-hemispherical liners basically stops the penetration ability at 300μs. In terms of penetration depth, the hypercumulative liner is the largest and the sub-hemispherical liner is the smallest. The sub-hemispherical liner gets the largest perforation aperture. The eccentric sub-hemispherical liner gets the best comprehensive effect of penetration and expansion against the concrete target. The results of this paper can be used for reference in the structural design of the amorphous alloy liner.

Ultra-high performance concrete subjected to high-velocity projectile impact: implementation of K&C model with consideration of failure surfaces and dynamic increase factors

The K&C material model is widely used to numerically predict the responses of concrete structures against impact or blast loadings. In the literature, most of the K&C parameters are calibrated for normal strength concretes (NSCs), and are thus not directly applicable for ultra-high performance concretes (UHPCs). Moreover, many existing work on UHPCs involve ad-hoc calibrations of the K&C parameters, which may not be applicable for situations beyond the calibration conditions. In this study focusing on UHPCs, a systematic calibration of the K&C failure surfaces and dynamic increase factors (DIFs) is carried out based on available experimental data in the literature. General guidelines on the determination of other model parameters are also provided. Following this systematic determination of material parameters, the predictive capability of the K&C model is demonstrated by considering several sets of experimental data on high-velocity projectile impact (HVPI) against UHPCs, across a wide range of UHPC material properties and mix designs, specimen and / or projectile geometrical details, and loading conditions. Good numerical predictions in terms of penetration depth and crater size are obtained, which suggests that the proposed implementation procedure can be adopted with reasonable confidence, especially during preliminary studies where the relevant experimental data are limited / not available.

What Ultrasound Can and Cannot Do in Implantable Medical Device Communications.

Modern Active Medical Implantable Devices require communications to transmit information to the outside world or other implantable sub-systems. This can include physiological data, diagnostics, and parameters to optimise the therapeutic protocol. The available options are to use optical, radiofrequency, or ultrasonic communications. However, in all cases, transmission becomes more difficult with deeper transmission through tissue. Challenges include absorption and scattering by tissue, and the need to ensure there are no undesirable heating effects. As such, this paper aims to review research progress in using ultrasound as an alternative for deep tissue communications. We provide an empirical review of the technology and communication protocols that different groups have used, as well as comparing the implications in terms of penetration depth, implant size, and data rate. We conclude that this technique has promise for deeper implants and for intrabody communications between implantable devices (intrabody networks).

Investigation on the penetration of jacketed rods with striking velocities of 0.9–3.3 km/s into semi-infinite targets

In this study, a combined experimental, numerical and theoretical investigation is conducted on the penetration of semi-infinite 4340 steel targets by a homogeneous 93W rod and two types of jacketed rods with striking velocities of 0.9–3.3 km/s. The results show that the jacketed rods produced typical “co-erosion” damage at all test velocities, except for the 93W/1060Al jacketed rod, which switched from an early “bi-erosion” damage to later “co-erosion” damage at a striking velocity of 936 m/s. However, the homogeneous 93W rod always forms a large mushroom head during the penetration process. The damage mechanisms of these two types of jacketed rods differ for striking velocities of 0.9–2.0 km/s, but this difference gradually decreases with increased striking velocity. For velocities of 2.0–3.3 km/s, all three types of projectiles exhibit typical hydrodynamic penetration characteristics, and the damage mechanisms of the two types of jacketed rods are almost identical. For the same initial kinetic energy, the penetration performance of the jacketed rods is distinctly superior to that of the homogeneous 93W rods. Compared with jacket density, jacket strength shows a more significant influence on the damage mechanism and penetration performance of the jacketed rod. Finally, an existing theoretical prediction model of the penetration depth of jacketed rods on semi-infinite targets in the co-erosion mode is modified. It transpires that—in terms of penetration depth—the modified theoretical model is in good agreement with the experimental and numerical observations for 93W/TC4 and 93W/1060Al jacketed rods penetrating semi-infinite 4340 steel targets.

OPTIMIZATION OF PROCESS PARAMETERS IN LASER WELDING OF HASTELLOY C-276 USING ARTIFICIAL NEURAL NETWORK AND GENETIC ALGORITHM

In this paper, an effort is made to determine the optimized parameters in laser welding of Hastelloy C-276 using Artificial Neural Network (ANN) and Genetic Algorithm (GA). CO2 Laser welding was performed on a sheet of thickness 1.6[Formula: see text]mm based on Taguchi L27 orthogonal array. Laser power, welding speed and shielding gas flow rate were chosen as input parameters and Bead width, depth of Penetration and Microhardness were measured for assessing the weld quality. ANN was applied for modeling the welding process parameters i.e. heat input, welding speed and gas flow rate. Various learning algorithms such as Batch Back Propagation (BBP), Incremental Back Propagation (IBP), Quick Propagation (QP) and Levenberg–Marquardt (LM) were comprehensively tested for estimating the output parameters and a comparison was also made among them, with respect to prediction accuracy. BBP method was found to be the best learning algorithm. Experimental validation test was performed based on the ANN and GA predicted optimized responses and this welding input parameters provided satisfactory weld metal characteristics in terms of penetration depth, bead width and microhardness.

The penetration of limestone targets by rigid projectiles: Revisited

We reanalyze the results from a set of terminal ballistics tests in which large limestone targets were impacted by similarly shaped rigid projectiles having different sizes. Our first goal is to show that the data in terms of penetration depths as a function of impact velocity can be accounted for by a model in which the limestone’s resistance to penetration is constant throughout the penetration process. It turns out that the actual values of this penetration resistance, as derived from the data, decrease with the projectile’s size. This is a clear manifestation of a scaling issue in the terminal ballistics of the limestone rock. In order to account for this issue we assume that it is closely related to the size effect in the compressive strengths of rock specimens. Finally, we offer a simple procedure by which one can define a surrogate material model for the targets in numerical simulations, in order to predict the penetration depths in limestone, and possibly other rock targets, under both normal and oblique impacts.

The importance of physical parameters for the penetration depth of impregnation products into cementitious materials: Modelling and experimental study

The performance of impregnation treatments used for protection and remediation of porous building materials relies on sufficient penetration depth. The penetration of sol–gel impregnation products into partially saturated porous material is driven by capillary suction and depends on material properties, such as pore size distribution on one hand, and on the other hand on sol physical properties, viscosity, density, surface tension and contact angle, along with the time in which the sol gels. In this work we analyse, by the way of modelling and experiments, the penetration depth of a sol–gel impregnation product as the function of pore size distribution and sol properties. The main goal is to determine the importance of sol’s physical properties for the penetration depth for a specific pore size, which will serve as a basis of the optimization of impregnation products to maximize their penetration depth. The model is first calibrated in terms of penetration depth and sol uptake by the experimental data obtained from mortar samples each with a specific pore-size distribution. The correlation between penetration depth and physical parameters is then established by the use of Monte-Carlo method. The results show that the most important parameters for the optimization are surface tension, whose influence increases for larger pores, and gelation time, which with decreasing importance for larger pores.

Mesoscale modelling of laser powder-based directed energy deposition process

Laser Powder-based Directed Energy Deposition (LP-DED) process is a cutting-edge Additive Manufacturing (AM) technology for metal part repair and production. The disruptive potentialities of LP-DED are nowadays limited by the difficulty in the identification of the optimized set of process parameters, typically obtained from long and expensive experimental trials. In this work, a thermal simulation tool able to predict material deposition behaviour is developed using a finite element code. An original method is defined to model the material addition and energy flow. The forecasting capabilities of the model in terms of penetration depth and track dimensions are evaluated by comparing the numerical outcomes with experimental data.