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Gaps and void pockets are inevitably present in tailored thermoplastic composite preforms manufactured via automated fiber placement (AFP). Filling these gaps and voids can be challenging during the consolidation due to the high viscosity of thermoplastic composites, especially in the case of vacuum-bag-only (VBO) consolidation, where the applied pressure is limited. Therefore, the current work investigates whether one bar pressure is sufficient to fill the gaps and voids during VBO consolidation. For this purpose, two experiments are performed. First, a hot plate setup is built and used to capture the real-time gap-filling behavior during the VBO consolidation. Second, VBO consolidation of tailored preforms is performed to study the filling of ply-drop induced void pockets. Here, the tailored preform consists of plies of different orientations dropped at different locations to verify if one bar pressure available during the VBO process is sufficient to fill the void pockets. The results from both experiments answered the main question that one bar pressure is sufficient for filling the gaps and void pockets for the given material systems, and further, it was confirmed that the transverse squeeze flow was dominant in filling gaps. However, in the case of fillings of ply-drop induced void pockets, the orientation of the dropped ply and covering plies majorly dictated the filling behavior. [ABSTRACT FROM AUTHOR]

This study incorporated a heating roller into a 3D printer based on fused filament fabrication to develop a layer-wise compaction 3D printer. The heating roller facilitates heat compaction during 3D printing to reduce voids and enhance the interface. Coupon specimens were 3D-printed using a continuous carbon fiber-reinforced nylon composite, and the effects of the process on the microstructure and mechanical properties were analyzed. The porosity was measured using X-ray computed tomography, which demonstrated an effective reduction due to the heat-compaction process. The enhanced mode-I interlaminar fracture toughness was assessed using a double-cantilever beam test. The reduced voids and improved interface led to enhanced bending properties of the composite. The bending fracture surface exhibited a reduced compression failure area as a result of the heat compaction process, indicating an improvement in the compression load-bearing capacity. [ABSTRACT FROM AUTHOR]

This study investigates the contemporary thermoelasticity theories in a photothermal semiconducting medium with voids influenced by the electromagnetic field. Boundary conditions of the phenomenon were based on the equations that regulate it concerning the stresses, carrier density, change in volume fraction field and temperature on the surface space. The equations were solved in normal mode technique, and the results are displayed by graphs. A comparison has been made with the findings of the literature when neglecting the new external parameters. The findings show that the presence or absence of electromagnetic field and carrier density significantly impacts on the phenomenon. From the results obtained, it is clear that the effects of electromagnetic field, carrier density, volume fraction and thermal relaxation times are very pronounced and applicable in diverse fields including geophysics, astronomy, engineering, biology, etc. [ABSTRACT FROM AUTHOR]

We explore how the definition of a void influences the conclusions drawn about the impact of the void environment on galactic properties using two void-finding algorithms in the Void Analysis Software Toolkit: Voronoi Voids (V2), a Python implementation of ZOnes Bordering On Voidness (ZOBOV); and VoidFinder, an algorithm that grows and merges spherical void regions. Using the Sloan Digital Sky Survey Data Release 7, we find that galaxies found in VoidFinder voids tend to be bluer and fainter and to have higher (specific) star formation rates than galaxies in denser regions. Conversely, galaxies found in V2 voids show less significant differences when compared to galaxies in denser regions, less consistent with the large-scale environmental effects on galaxy properties expected from both simulations and previous observations. These results align with previous simulation results that show V2-identified voids "leak" into the dense walls between voids because their boundaries extend up to the density maxima in the walls. As a result, when using ZOBOV-based void-finders, galaxies likely to be part of wall regions are instead classified as void galaxies, a misclassification that can be critical to our understanding of galaxy evolution. [ABSTRACT FROM AUTHOR]

Purpose: This article examines the impact of incorporating Nanodiamonds into jute fiber-reinforced epoxy resin composite panels which are used as acoustic material for indoor applications. Materials and methods: The laminates were fabricated by VRIP (Vacuum resin infusion process). The percentage of nanodiamonds that were incorporated into the mixture is 0.2 wt%, 0.4 wt%, and 0.6 wt%, respectively. The sound absorption coefficient, modal analysis, flame retardant, voids, and dispersion of nanodiamonds in the laminates were evaluated. Using an impedance tube, the sound absorption coefficient was determined. Impulse hammer excitation method is employed to find natural frequency and vibration damping. Flame-retardant properties were evaluated by the UL-94 vertical and horizontal flammability tests. The dispersion of nanodiamonds (NDs) was studied using a scanning electron microscope (SEM). The voids were evaluated using a micro-x-ray computed tomography (CT) scanner. Results: The sound absorption coefficient showed significant improvement with the addition of nanodiamonds at concentrations of 0.4 wt.%. NDs (0.86) and 0.6 wt.%. NDs (0.89) at higher frequencies when compared with other panels. Enhancement of damping factor and natural frequency values (0.4%). Formation of char by nanodiamonds enables the flame-retardant property of material. The scanning electron microscopy (SEM) examination revealed a fine dispersion of nanodiamonds (NDs) in 0.4% wt. NDs laminate. CT scan results show the existence of closed cavities. Conclusion: The jute fiber composite panels made by integrating nanodiamonds have shown the qualities of good sound absorption material which can be used in indoors for sound absorption. [ABSTRACT FROM AUTHOR]

This paper addresses a significant research gap in the study of surface waves propagation in a nonhomogeneous, within a magneto-thermoviscoelastic material of higher order, initial stress, rotation, gravity effects and voids. This study provides analytical solutions for surface waves propagating through a medium consisting of a magneto-thermoelastic material with voids under the rotation, electro-magnetic field, gravity field and initial stress. The analytical solutions are derived for the displacement components, volume fraction, temperature to Stoneley and Rayleigh waves are computed numerically and presented graphically considering the external parameters impact. Furthermore, this investigates how magnetic field, voids, gravity, initial stress and fiber-reinforced parameters influence these wave phenomena. This investigation provides valuable insights into the synergistic dynamics among electric constituents, voids, Stoneley and Rayleigh waves propagation, enabling advancements in sensor technology, augmented energy harvesting methodologies, and pioneering seismic monitoring approaches. For certain materials, numerical simulations are provided and graphically displayed. The results of this study reveal several unique cases that significantly contribute to the understanding of Rayleigh and Stoneley waves propagation within this intricate material system, particularly in the presence of voids.

Abstract This paper aims to obtain solutions in terms of the complex potential structure for the plain strain problem of an elastic micropolar and isotropic body with pores. The constitutive equations on which the method is applied and is useful are the well-known equations of the elasticity theory for the above-mentioned body. We intend to solve the Kirch problem using the procedure of complex variables.

Transition metal nitrides have extensive applications, including magnetic storage devices, hardware resistance coatings, and low-temperature fuel cells. This study investigated the structural, electrical, and mechanical properties of thin zirconium nitride (ZrN) films by examining the effects of laser irradiation times. Thin ZrN films were deposited on glass substrates using pulsed DC magnetron sputtering and irradiated with a diode laser for 6 and 10 min. Characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), nanoindentation, and four-point probe techniques. Extended laser irradiation times resulted in increased numbers of peaks on XRD analysis, indicating enhanced crystalline behavior of thin ZrN film. SEM analysis revealed surface voids, while HRTEM showed nanostructured ZrN with uniform plane orientation. The electrical properties of the thin ZrN film improved with extended laser irradiation, as demonstrated by a reduction in sheet resistance from 0.43 × 109 Ω to 0.04 × 109 Ω. Additionally, nanoindentation tests revealed an increase in hardness, rising from 8.91 GPa to 9.36 GPa. [ABSTRACT FROM AUTHOR]

The current research presents a new model on a volume fraction branch of Knowledge and photothermal effect in a semiconductor generalized thermoelasticity medium according to the Lord-Shulman Theory. The governing equations are provided considering voids, photothermal, semiconducting, and the theory of generalized thermoelasticity. The authors make use of the normal mode examination to solve the order of the equations in this phenomenon under the boundary conditions. The achieved results demonstrate the effect of photothermal, voids, the process of semiconductor, and the thermic relaxation time. The compared physical fields are given analytically and displayed in graphs. The achieved results display the possibility of applying the combination of the photothermal and semiconductors medium in biophysical, industries, structures, engineering, and chemical products with consideration of the photothermal, semiconducting, and voids. [ABSTRACT FROM AUTHOR]

The Lamb-type waves in the homogeneous isotropic thermally conducting porous plate immersed in the inviscid fluid in the context of the Lord and Shulman theory of thermoelasticity are studied. To seek out solutions, the Helmholtz decomposition technique is used. Plugging the solutions in the appropriate boundary conditions, a secular equation is derived for the symmetric and anti-symmetric family of wave modes. It is found that shear horizontal wave mode uncouples itself from the coupled system of waves. Particular cases of the secular equation have also been deduced in the absence of fluid or certain energy fields such as thermal field and/or volume fractional field. Different regions of the secular equation are obtained. Furthermore, these regions have been led to peculiar cases such as short-wavelength, and long-wavelength waves. The amplitude of displacement, change in volume fraction field, and temperature distribution is computed and compared with prior accomplished research work. The numerical computations are carried out for a porous magnesium plate immersed in water to understand the behavioral pattern of waves, and the various graphs are plotted to defend the analytical findings. [ABSTRACT FROM AUTHOR]

The present work is devoted to discuss the transient wave propagation in an isotropic homogenous thermoelastic spherical body with voids due to harmonically varying heat sources in the context of nonlocal thermoelasticity. The constitutive relations and the governing equations are resolved by applying harmonic variations in time and transformed into coupled ordinary differential equations. The outer and the inner surfaces of the sphere are kept stress-free and free from void concentration. A harmonically varying heat source is supplied on the inner surface along the radial direction and the outer surface is assumed to be isothermal. Numerical simulations are implemented to the analytical results with the support of MATLAB software tool. Numerically, generated data are presented graphically for the field variables of interest (temperature, stresses, cubical dilation, displacement and void volume fraction field) and at the end analysis of these results are given. [ABSTRACT FROM AUTHOR]

This work presents results of numerical simulations to investigate the effect of different void percentages on composite materials' Coefficient of Thermal Expansion (CTE) and local stress fields. A random distribution of voids is considered within the Representative Volume Element (RVE) matrix, and different types of microstructures are considered, including square-packed and randomly distributed fibers. The use of a higher-order beam model within the framework of Carrera Unified Formulation (CUF) leads to a Component-Wise (CW) approach, resulting in an accurate, 3D description of the cross-section although using a 1D formulation. Numerical results for different fiber volume fractions and void concentration percentages demonstrate the agreement of the computed effective coefficients of thermal expansion of the present micromechanical thermoelastic model with references from the literature. The local stress fields are affected by voids, with higher effects over the matrix. Furthermore, higher void fractions lead to higher variability of stress peaks. [ABSTRACT FROM AUTHOR]

This study utilizes Direct FE2 multiscale simulation techniques to propose an innovative approach for analyzing hydrogen diffusion in Zircaloy cladding. This method combines finite element simulations at two scales into a monolithic framework by utilizing downscaling rules and scaling factors. Through the investigation, it was found that voids induce non-uniform diffusion of lattice hydrogen, demonstrating a strong correlation between trapped concentration and microstructure. Additionally, the accumulation of trapped hydrogen leads to localized plastic deformation and a reduction in effective diffusivity. Furthermore, two representative volume elements were established to depict the void distribution at various stages of its evolution. It is evident that in the initial phases of void evolution, the hydrogen-induced softening effect facilitates crack propagation deep within the zirconium alloy cladding. Moreover, as void evolution progresses into the second stage, this effect intensifies the incidence of localized damage at the narrow inter-void ligaments. [ABSTRACT FROM AUTHOR]

In this work, the Dy 2 O 3 -Al 2 O 3 -SiO 2 (DASN) and Dy 2 O 3 -Al 2 O 3 -SiO 2 -TiO 2 (DAST) glass fillers were used for joining alumina ceramic. During the cooling process of the alumina/DASN/alumina joints, Dy 2 Si 2 O 7 and Al 2 O 3 were precipitated simultaneously and gradually grown. As a result, voids were formed due to the poor flowability of the glass ceramic filler and the large density difference between the glass filler and Dy 2 Si 2 O 7 crystals. On the contrary, the addition of TiO 2 altered the sequence of the crystalline phase precipitation during the cooling process. During cooling from the joining temperature (1450 °C) to 1100 °C, only Dy 2 Si 2 O 7 was formed in the brazing seam. Simultaneously, the flowing glass phase was able to fill the spaces caused by the density differences. When the growth of Dy 2 Si 2 O 7 phase ceased, the Al 2 O 3 phase began to precipitate. Therefore, the voids caused by density differences can be eliminated in the alumina/DAST/alumina joints with high crystallinity. The optimal flexural strength of alumina/DAST/alumina joints tested at room temperature and 1000 °C reached 350 MPa and 158 MPa, respectively. [ABSTRACT FROM AUTHOR]

Highlights Carbon fiber reinforced resin matrix composites, when subjected to multi‐angle delamination during vacuum hot pressing, suffered from defects such as uneven fiber distribution, resin‐rich zones, and voids. These defects caused varied damage and failure behaviors in the composites, seriously affecting their mechanical properties. In this paper, the defect distribution, tensile and flexural properties, and damage behaviors of multi‐angle lay‐up specimens prepared in an autoclave were studied. The results indicated that irregularly shaped voids in laminates with a 0° angle difference primarily led to local stress concentration. Elliptical and elongated voids in laminates with a 90° angle difference were mainly susceptible to delamination. The [0/90]8 layer exhibited the best overall mechanical properties. The proportion of 0° laminates had a direct impact on the mechanical properties, with 0° contact laminates on the bending‐compression side capable of withstanding higher bending loads. The [+45/−45]8 plyer demonstrated pseudo‐delayed behavior, enabling the laminate to show better toughness under load. Variations in damage due to the proportions and positions of the laminates influenced the mechanical properties and damages behavior of multi‐angle laminates. Angular differences were observed to affect void and resin distribution. The best overall mechanical properties were attributed to [0/90]8 laminates. Pseudo‐delay behavior was exhibited by [+45/−45]8 laminates. Proportion of 0° layers impacted mechanical properties. Greater bending loads were withstood by the 0° contact layer. [ABSTRACT FROM AUTHOR]

In this study it is approached a linear model for the mixture of two Cosserat bodies having pores. It is formulated the mixed problem with initial and boundary data in this context. The main goal is to show that the coefficients that realize the coupling of the elastic effect with the one due to voids can vary, without the mixture being essentially affected. In a more precise formulation, this means that a small variation of the coefficients in the constitutive equations of the two continua causes only a small variation of the solutions of the corresponding mixed problems, that is, the continuous dependence of the solutions in relation to these coefficients is ensured. The considered mixture model is consistent because all estimates, specific to continuous dependence, are made based on rigorous mathematical relationships. [ABSTRACT FROM AUTHOR]

Given the functional and aesthetic quality expected from concrete surfaces, this study investigated the influence of different formwork materials on their surface density, porosity, voids, and elementary chemical composition by relying on X-ray Microtomography (μCT), Scanning Electronic Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). The formwork materials assessed were galvanized steel, regular plywood (pink), marine plywood, polyvinyl chloride (PVC), and silicone. μCT showed that distinct formwork affected the surface density of the concrete. In this case, specimens cast within silicone and marine plywood had similar pore volumes although different pore sizes, whereas PVC led to the highest pore volume with small pore sizes. Galvanized steel and regular plywood resulted in similar porosity. SEM showed that the concrete surfaces produced with marine plywood formwork had the highest void content. EDS identified surface products resulting from the contact of concrete with the different formwork materials, suggesting the potential migration of chemical elements. This research significantly contributes to optimizing formwork material selection and enhancing concrete quality and durability. Moreover, it establishes a foundation for further investigations into how formwork materials affect concrete surfaces and the pathological manifestations potentially arising from the molding process. [ABSTRACT FROM AUTHOR]

This paper addresses a significant research gap in the study of surface waves propagation in a nonhomogeneous, within a magneto-thermoviscoelastic material of higher order, initial stress, rotation, gravity effects and voids. This study provides analytical solutions for surface waves propagating through a medium consisting of a magneto-thermoelastic material with voids under the rotation, electro-magnetic field, gravity field and initial stress. The analytical solutions are derived for the displacement components, volume fraction, temperature to Stoneley and Rayleigh waves are computed numerically and presented graphically considering the external parameters impact. Furthermore, this investigates how magnetic field, voids, gravity, initial stress and fiber-reinforced parameters influence these wave phenomena. This investigation provides valuable insights into the synergistic dynamics among electric constituents, voids, Stoneley and Rayleigh waves propagation, enabling advancements in sensor technology, augmented energy harvesting methodologies, and pioneering seismic monitoring approaches. For certain materials, numerical simulations are provided and graphically displayed. The results of this study reveal several unique cases that significantly contribute to the understanding of Rayleigh and Stoneley waves propagation within this intricate material system, particularly in the presence of voids. [ABSTRACT FROM AUTHOR]

Voids behind tunnel linings can be formed either during or after the construction phase, occurring due to inadequate backfilling, substandard workmanship, water erosion, or gravitational forces. Investigations into numerous tunnels in which collapses occurred while in operation have indicated that voids behind the liner constitute the primary contributors to these failures. Consequently, it is imperative to devise lining reinforcement strategies tailored to the specific conditions encountered in the field. Fiber-reinforced plastic (FRP) represents a viable alternative construction material that has been widely utilized in the reinforcement of concrete structures. It is essential to quantitatively assess the reinforcing effect of FRP grids when they are employed in the restoration of deteriorated tunnel linings, thereby facilitating the development of effective maintenance designs. In this study, we aimed to enhance the sensitivity analysis of the reinforcement method by evaluating the impact of voids through the analysis of bending moments and axial forces within the tunnel lining. The effects of voids based on the different locations in which they occur were explored numerically through an Elastoplast finite element analysis. The study involved simulating tunnel linings that had been reinforced with FRP grids and assessing the effects of such reinforcement in tunnels afflicted with various structural problems. Based on the outcomes of these simulations, the internal forces within the lining are scrutinized, and the efficacy of the reinforcement is appraised. [ABSTRACT FROM AUTHOR]

This paper aims to obtain solutions in terms of the complex potential structure for the plain strain problem of an elastic micropolar and isotropic body with pores. The constitutive equations on which the method is applied and is useful are the well-known equations of the elasticity theory for the above-mentioned body. We intend to solve the Kirch problem using the procedure of complex variables. [ABSTRACT FROM AUTHOR]

The production of high-performance carbon fibers relies heavily on the structural transformations of polyacrylonitrile (PAN) fiber during processing. In this article differential scanning calorimetry (DSC), synchrotron small-angle X-ray scattering (SAXS), and synchrotron wide-angle X-ray diffraction (WAXD) were used to study the changes of the thermal properties, voids and crystal structure of the PAN precursor fibers on industrial lines during the continuous processing stages, i.e., after the treatment in the coagulation bath, after stretching in boiling water and after stretching in high-temperature steam. The findings of this study suggest that after boiling water stretching the molecular chain motion of the PAN precursor fiber weaken, resulting in the expansion of the voids. After high-temperature steam stretching the voids became elliptical and oriented in the stretching direction. Although the boiling water stretching process partially damaged the (100) crystal planes of the PAN precursor fibers, it does not hinder their overall crystalline structure. The high stretching ratio primarily affected the orientation of the molecular chains. This orientation, even in the context of partial crystal plane disruption, further promoted the crystallization of the (100) crystal planes in the fibers. These experiments explored the correlation between the processing technology and fiber structure transformation of PAN-based carbon fibers, resulting in producing a guide for the preparation of high-performance carbon fibers with fewer defects. [ABSTRACT FROM AUTHOR]

The reliability of solder joints in electronic packaging was investigated by finite element analysis (= FEA), focusing on the effects of intermetallic compound (= IMC) layers and voids. The results showed that changes in the elastic modulus of the IMC layer of around 20 % did not significantly affect solder joint life. This means that when the modulus of elasticity changes, it is not only the change in modulus that is considered, but also the change in creep properties. In addition, the FEA evaluation of voids underscores the importance of considering equivalent creep strain and cautions against relying solely on the FEA results when void locations do not coincide with maximum equivalent creep strain values. Currently, it is difficult to predict the tendency of voids to affect solder creep life based on FEA analysis results alone. A limitation is that if voids are present in the solder not at the IMC interface, the solder creep life may be underestimated. This study contributes to a better understanding of the complex thermal-fatigue life that solder joint reliability in electronic packaging. [ABSTRACT FROM AUTHOR]

Old and abandoned mine workings become inaccessible with time owing to safety issues thereby demanding insight review of strata overlying such areas. Electrical Resistivity Tomography (ERT) survey was carried out at locations within Kajora area of Eastern Coalfield Limited (ECL) in Raniganj coalfield, India to assess the present strata condition for the proposed high voltage electric transmission layout. Parallel 2D ERT profiles were carried out with 20 m offset covering the study area. Considering the sensitiveness in horizontal direction i.e., identification of vertical structures, the Dipole-Dipole array methodology was implemented. The acquired data sets were filtered and processed using Prosys-II software. L-curve criteria for misfit data was used for proper interpretation of subsurface features. Non-linear least-squares regularized optimization method and 3D ERT volumetric model were performed by combining 2D ERT parallel profiles data sets for better resolution of underground old mine working and accurately map the status of mine workings. High resistivity magnitude ranging between 200 Ωm to 1600 Ωm indicated intact bedrock and solid pillar. Depillared workings area (either dry-filling or air-filled) was identified through anomalous high resistivity magnitude of more than 1600 Ωm. The data generated were also validated with underground working plan and available borehole data. Combination of 2D ERT and 3D ERT techniques against each profile was found to be effective for detection of strata condition for safe installation of terrestrial high voltage electric transmission towers. [ABSTRACT FROM AUTHOR]

The present article is concerned with the reflection of plane harmonic waves in a nonlocal micropolar thermoelastic medium having void pores in the context of dual-phase-lag and Lord-Shulman models. Two sets of coupled shear waves and three sets of coupled longitudinal waves are shown to exist. When a coupled longitudinal displacement wave is made incident, the reflection coefficients of the various reflected waves and their respective energy ratios are computed analytically and the numerical computation is carried out with the help of MATLAB software. For a particular model, the influence of nonlocal, voids and micropolar parameters on the variations of reflection coefficients and energy ratios of various reflected waves is presented graphically. It is verified that during reflection phenomenon, the sum of energy ratios is equal to unity at each angle of incidence. A comparison between the dual-phase-lag model and Lord-Shulman model is also depicted graphically. [ABSTRACT FROM AUTHOR]

The response of elastic waves upon encountering the boundary between two elastic media is investigated in the present work. Whereas the top medium is thermoelastic isotropic porous, the below medium is thermoelastic rotating porous diffusive. There is an uncoupled transmitted SV -wave propagating through the medium, and the lower medium is rotating with some fixed angular frequency. When the incident wave hits the boundary, it produces four transmitted waves and five coupled quasi-reflected waves. The system is divided into longitudinal and transverse components using the Helmholtz decomposition theorem. Analytical computations of speed and reflection coefficients for transmitted and reflected waves are performed using LS theory. The outcomes are graphically represented for a particular material subject to nonlocal and fractional-order influences. Wave characteristics, such as speed and reflection coefficients for transmitted and reflected waves, are plotted versus angular frequency and angle of incidence using MATLAB programing. The conservation of energy has also been verified. In the absence of rotation, hall current, voids, viscoelasticity, and diffusion in the medium, the previous results in the literature are obtained. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate the effects of diffusion and thermal stress by pulsed laser heating on thermoelastic solids with cavities in the context of a three-phase delay model. The dimensionless governing equations are established, and then the exact expressions of temperature field, displacement component, stress component, concentration field and volume fraction field changes are obtained by using normal mode technique. The material is an isotropic uniform elastic half-space heated by a non-Gaussian laser beam with pulse duration 0.002 ps. Using a magnesium crystal element as an application, the predictions of the model for diffusion and laser pulse-induced three-phase hysteresis on porous thermoelastic media are compared with those of the Green-Naghdi type III theory. The obtained thermal change results are verified by comparison with two theories of thermoelasticity, the three-phase lag (3PHL) model and the Green and Nagdi type III theory. Plot the field quantities to examine the effect of the laser pulse at two different values of time and the effect void parameter. This study also yields some interesting special cases. [ABSTRACT FROM AUTHOR]

Propagation of Rayleigh-type waves is investigated in a half-space composed of nonlocal micropolar thermoelastic material containing void pores. Dispersion relation is derived for a mechanically stress-free and thermally insulated boundary surface of the half-space. The particle motion during the propagation of the waves is found to follow elliptical path. Numerical computations for a specific material are performed to analyze the characteristics of propagating Rayleigh-type waves in detail. Comparison between the phase speed and corresponding attenuation coefficient in some particular cases is also carried out. The effect of various parameters on the characteristics of waves in question is also studied. [ABSTRACT FROM AUTHOR]

The large-scale universal structure comprises strands of dark matter and galaxies with large underdense volumes known as voids. We measure the fraction of the line of sight that intersects voids for active galactic nuclei (AGN) detected by Fermi Large Area Telescope (LAT) and quasars from the Sloan Digital Sky Survey (SDSS). This “voidiness” fraction is a rudimentary proxy for the density along the line of sight to the galaxies. The voidiness of SDSS-observed quasars (QSOs) is distinctly different from randomly distributed source populations, with a median p -value of 4.6 × 10 ^−5 and ≪1 × 10 ^−7 , when compared with 500 simulated populations with randomly simulated locations but matching redshifts in the 0.1 ≤ z < 0.4 and 0.4 ≤ z < 0.7 intervals, respectively. A similar comparison of the voidiness for LAT-detected AGN shows median p -values greater than 0.05 in each redshift interval. When comparing the SDSS QSO population to the LAT-detected AGN, we mitigate potential bias from a relationship between redshift and voidiness by comparing the LAT-detected AGN to a “redshift-matched” set of SDSS QSOs. The LAT-detected AGN between a redshift of 0.4 and 0.7 show higher voidiness compared to the redshift-matched SDSS QSO populations, with a median p -value of 2.3 × 10 ^−5 (a 4.1 σ deviation). No deviation is found when comparing the same populations between redshifts of 0.1 and 0.4 ( p > 0.05). We do not study possible causes of this voidiness difference. It might relate to propagation effects from lower magnetic or radiative background fields within voids or to an environment more favorable for gamma-ray production for AGN near voids.

Background and purpose: To achieve a successful root canal treatment, it is necessary to have a sealer with ideal characteristics that seal the permanent filling of the tooth canal. Over time, various sealers with different compositions have been introduced to increase the obturation quality of tooth root canals, and many studies are still ongoing to find the ideal sealer. This study aims to evaluate the obturation quality of Endoseal MTA sealer based on the void and spreader track in the root canal using intraoral digital radiography (PSP) and compare it with Adseal and MTA Fillapex. Materials and methods: This laboratory study was conducted on 36 central maxillary single-canal permanent human teeth with the same shape and in the pre-clinic of the dental school of Mazandaran University of Medical Sciences. Root canal preparation was done with the Denco rotary system up to size F3 according to the manufacturer's instructions. During preparation, sodium hypochlorite 5.25% was used for washing, and finally EDTA 17% and sodium chlorite 5.25% were used to remove the smear layer. The teeth were dried with a paper cone. The samples were randomly divided into 3 groups and were filled with gutta-percha and sealers; MTA Fillapex, Endoseal MTA, and Adseal by lateral compaction method using Master Cone 35 and cone 20. After the sealers were set completely for 24 hours, PSP imaging was done with a parallel technique, buccolingually and mesiodistally, from the root canal of the teeth, and the presence of void and gaps in the form of spreader track in the three apical, middle and coronal regions, was evaluated with 3 independent observers. The data were evaluated with chi-square or Fisher's exact test, and items less than 0.05 were considered significant. Results: In the current study, the obturation quality of MTA Fillapex, Endoseal MTA, and Adseal sealers was investigated on 36 teeth based on void and gap in the form of spreader track. These evaluations were done according to the direction and location of the sealers. In these evaluations, Adseal sealer had the lowest and MTA Fillapex had the most prevalence of spreader track prevalence, although these differences were not significant based on the chi-square test and there was no significant difference between the prevalence of Spreader track among the three sealers. The void was observed only in the Endoseal group in coronal (mean: 0.5) and apical (mean: 0.7) areas. The results of the Chi-square test showed that there was no significant relationship between the prevalence of void with coronal, middle, and apical sites in Endoseal (P

Ground Penetrating Radar (GPR), has emerged as a powerful non-invasive geophysical technique for detecting subsurface utilities, voids, and other subsurface anomalies. However, despite its widespread use in geophysical investigations, and construction management, there is lack of available datasets containing B-scan images of the subsurface features publicly that could be used to train deep learning models for automated anomaly detection. This data article aims at contributing to fill up this gap by creating a dataset specifically designed for automatic detection of subsurface utilities, and voids using deep learning. The dataset consists of 2,239 Radargram images in JPEG format obtained from GPR surveys conducted in urban environments to identify utilities such as pipes, cables, and underground voids. The importance of this dataset lies in: (1) contribute to fill the gap of lack of GPR data, (2) the universality of the data, (3) its potential to enhance the accuracy and efficiency to detect subsurface anomaly through the application of deep learning models, (4) GPR surveys are highly effective but still expensive, and its processing is time-consuming. By providing this labelled dataset for deep learning model training, this can facilitate the development of automated systems, capable of detecting subsurface anomalies effectively, which could reduce manual errors.

AbstractThis paper investigates Love-type wave propagation in a multilayered, elastic, prestressed solid half-space with voids. Using the Haskell matrix method, the dispersion relation is derived for a stress-free boundary surface. Two distinct dispersive fronts of Love-type waves, propagating at different speeds, are identified. One behaves like waves in a prestressed elastic half-space, while the other is novel due to voids. Analytical expressions for three-layered and two-layered models are provided. Graphical representations compare the dispersion curves, highlighting differences and dependencies. The study explores how void parameters, initial stress, and layer thickness influence phase velocity, with applications in various engineering fields. [ABSTRACT FROM AUTHOR]

Highlights 2.5D woven composite material inevitably produces void defects in its production process, which will seriously reduce its mechanical properties and reduce its service life. In this paper, the effects of void defects on the mechanical properties of 2.5D woven composites were studied by multi‐scale analysis. An improved Halpin‐Tsai semi‐empirical model is proposed to calculate the elastic properties of yarns with porous defects and verified by finite element method. A microscale representative volume unit (RVE) for predicting the elastic constants of composites with pore defects is established. Theoretical analysis and finite element analysis were used to verify the micro scale, and finite element analysis and experiment were used to verify the micro scale. The effect of porosity on the elastic properties of micro‐scale RVE was studied in detail. The results show that the model is reasonable and accurate in predicting the mechanical properties of yarns and composites. In addition, the effect of porosity on the mechanical properties of 2.5D woven composites is significant. An improved Halpin‐Tsai semi‐empirical model is proposed, which makes the microscale theoretical analysis of 2.5D woven composites better consistent with the finite element analysis. The void position obstructs the stress transfer of the matrix, and the stress concentration phenomenon also occurs. The void content has an effect on the mechanical properties of composites at both micro and micro scales. [ABSTRACT FROM AUTHOR]

Photothermal transport process and voids in solids are important phenomena in a variety of engineering approaches and scientific disciplines. For this purpose, the photothermal theory is being utilized to study the coupling between elastic waves and plasma waves in a semiconducting medium with voids. The basic governing equations for photothermal waves are derived in the framework of hyperbolic two-temperature theory and Green–Lindsay model. Normal mode analysis method is used to obtain the physical field distributions under investigation. A moving thermal load is applied at the outer free surface of the medium to obtain the complete solution. Expressions are calculated numerically for silicon (Si) material and presented to observe the variations of the field quantities. The effects of various key parameters on the physical fields are also shown graphically. Special cases that are consistent with the earlier findings have been obtained. Although, numerous studies do exist on the deformation analysis in a photothermoelastic medium under different thermoelasticity theories. However, no research emphasizing thermodynamical analysis of the photothermal transport process in a hyperbolic two-temperature semiconducting medium with voids under the influence of gravity and Hall current has been carried out. This provides us a motivation to study the current research. Chemical engineering, geophysics, earthquake engineering, soil dynamics, high-energy particle physics, nuclear fusion, aeronautic biomechanics, bone mechanics, and petroleum industry are the major application areas of the photothermolelasticity theory. [ABSTRACT FROM AUTHOR]

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In this paper we approach the linear mixed problem with initial and boundary values for a Cosserat body which is elastic and has pores. We coupled the equations characterizing the pores evolution with basic equations that describing the elastic deformations of the Cosserat body. The coupling is done by means of predetermined coefficients. To prove the continuous dependence of the solutions, we introduce an adequate measure which is useful in obtaining of some estimations with respect to the gradient of elastic deformations and regarding the gradient of a specific the application, introduced to characterize the behavior of the pores. [ABSTRACT FROM AUTHOR]

Background and purpose: To achieve a successful root canal treatment, it is necessary to have a sealer with ideal characteristics that seal the permanent filling of the tooth canal. Over time, various sealers with different compositions have been introduced to increase the obturation quality of tooth root canals, and many studies are still ongoing to find the ideal sealer. This study aims to evaluate the obturation quality of Endoseal MTA sealer based on the void and spreader track in the root canal using intraoral digital radiography (PSP) and compare it with Adseal and MTA Fillapex. Materials and methods: This laboratory study was conducted on 36 central maxillary single- canal permanent human teeth with the same shape and in the pre-clinic of the dental school of Mazandaran University of Medical Sciences. Root canal preparation was done with the Denco rotary system up to size F3 according to the manufacturer's instructions. During preparation, sodium hypochlorite 5.25% was used for washing, and finally EDTA 17% and sodium chlorite 5.25% were used to remove the smear layer. The teeth were dried with a paper cone. The samples were randomly divided into 3 groups and were filled with gutta-percha and sealers; MTA Fillapex, Endoseal MTA, and Adseal by lateral compaction method using Master Cone 35 and cone 20. After the sealers were set completely for 24 hours, PSP imaging was done with a parallel technique, buccolingually and mesiodistally, from the root canal of the teeth, and the presence of void and gaps in the form of spreader track in the three apical, middle and coronal regions, was evaluated with 3 independent observers. The data were evaluated with chi-square or Fisher's exact test, and items less than 0.05 were considered significant. Results: In the current study, the obturation quality of MTA Fillapex, Endoseal MTA, and Adseal sealers was investigated on 36 teeth based on void and gap in the form of spreader track. These evaluations were done according to the direction and location of the sealers. In these evaluations, Adseal sealer had the lowest and MTA Fillapex had the most prevalence of spreader track prevalence, although these differences were not significant based on the chi-square test and there was no significant difference between the prevalence of Spreader track among the three sealers. The void was observed only in the Endoseal group in coronal (mean: 0.5) and apical (mean: 0.7) areas. The results of the Chi-square test showed that there was no significant relationship between the prevalence of void with coronal, middle, and apical sites in Endoseal (P<0.05). Conclusion: No difference was observed between the three sealers in the voids and gaps in the root canal. Based on the results of this study, the obturation quality of the above three sealers isn't different from each other. Although the presence of more void in Endoseal MTA sealer was not significant, it can indicate that the handling of this material is difficult, on the other hand, according to the manufacturer's recommendation, this sealer is recommended for single cone method and is not suitable for use in lateral compression method. [ABSTRACT FROM AUTHOR]

The present investigation deals with the rotation of magneto-thermoelastic solid with voids due to laser pulse and memory-dependent derivative in the context of a three-phase-lag model of generalized thermoelasticity. The bounding plane surface is heated by a non-Gaussian laser pulse and is subjected to prescribed stress. The entire porous medium is rotated with a uniform angular velocity. The normal mode analysis technique has been incorporated to solve the physical problem to obtain the exact expressions for the displacement components, stresses, temperature distribution, and change in the volume fraction field to represent the thermo-physical quantities graphically in the presence and the absence of rotation and magnetic field. The effect of linear and nonlinear kernel function and the effect of the delay-time parameter are also reported. [ABSTRACT FROM AUTHOR]