Physical Parameters Of Materials Research Articles

Comparative Investigation of Pressure Effect on Structural Stability, Electronic and Optical Response of LaXO<sub>3</sub> (X = Al, In, Ga) for Optoelectronic Applications

A first principle study intense on the density functional theory with Heydscuseria-Ernzerhof screened hybrid functional hybrid function (HSEO6) is used to assess the structural, Electronic, elastic, mechanical and optical responses of LaXO<sub>3</sub> (X = Al, In, Ga) perovskite materials. The compressive investigation under the external static isotropic pressure (P= 0 to 80GaP), phase stability, band structure and their important impact on the optical response of LaAlO<sub>3</sub>, LaInO<sub>3</sub> and LaGaO<sub>3</sub>. Electronic band structure shows that LaXO<sub>3</sub> (X = Al, In Ga) semiconductor with indirect band gap and an optically inactive response up to 20GPa, while the band gap becomes direct at 80GaP. There are gamma points (G-X-Q) at 80GPa and the band gap changes from indirect to direct nature. Under main desperation physical parameters of perovskite materials are well explained the response of TDOS, PDOS and EPDOS contour plots have been well understood for the full description of the band gap. It is further observed that the external pressure enhanced upto 40GPa both materials are significantly more mechanically stable compared to pristine LaXO<sub>3</sub> (X = Al, In, Ga) at 0GPa. The optical properties of LaAlO<sub>3</sub>, LaGaO<sub>3 </sub>and LaInO<sub>3</sub>, dielectric coefficient <i>(ε<sub>1</sub>, iε<sub>2</sub>)</i> have been employed along with the optical responses like absorption, energy loss function, reflectivity and reflective index are obtained in the energy scale from 0 to 60 eV. It was observed that static dielectric constant decreases with the decrease in optical band gap. The optical tunings under the effect of pressure which are good candidates in practical optoelectronic applications are extensively used and interpreted by the calculation of the dielectric function.

Parameter influence analysis of stochastic resonance and stochastic P-bifurcation for the shape-memory alloy laminate

This paper investigates the transverse vibration of an axially moving shape-memory alloy (SMA) fiber hybrid laminations under the combined action of transverse harmonic excitation and stochastic disturbance. Considering the shape memory alloy (SMA) fiber volume fraction random field, the kinetic energy and strain potential energy of SMA laminates are solved, and the axial motion equation of SMA laminates is derived according to Hamilton principle, a non-dimensional differential equation of the transverse vibration of the axially moving SMA laminated plates is obtained by adopting the Galerkin integral method. Considering the volume-fraction stochastic field, the stochastic natural vibration of a SMA laminate is analyzed. Considering the stochastic resonance of the SMA laminate under the action of Gaussian white noise and harmonic excitation, the effects of geometric parameters, physical parameters of materials, and temperature on the stochastic resonance behavior of the SMA laminate is analyzed. Finally, the effect of the stochastic P-bifurcation phenomenon of the parameters on the steady-state response of the SMA laminate is analyzed.

Electromechanical Device for Determining and Controlling Physical and Mechanical Parameters of Fiber Materials

Electromechanical Device for Determining and Controlling Physical and Mechanical Parameters of Fiber Materials

Ensuring the Safety of Buildings and Structures Damaged as a Result of Military Man-Made Actions

A significant number of destroyed buildings and structures during the military aggression of the Russian Fed-eration in Ukraine make it necessary for scientific organizations to solve new problems in the restoration of residential and public buildings. After explosive devices have hit the building, the first task is to identify the possibility of its further operation. Technical assessment of the damage level should be justified by using ex-perimental data on changes in the physical and mechanical parameters of construction materials and structures, which are strength, deformability, crack resistance, etc., as a result of the blast waves and fires that accompany explosions in the premises. An urgent task is to develop a methodology that takes into account the impact of explosions and fires caused by them so that structures can be calculated and their residual life estimated. For many decades, the State Research Institute of Building Constructions has been solving problems of assessing the technical condition of damaged buildings and structures as a result of man-made disasters and actions, fol-lowed by the development of technical solutions that ensure the necessary operational characteristics of these objects can be restored.

Calculating permissible deviations of vibration accelerations of printed circuit assemblies by simulation modeling

Objectives. A variety of technical condition control methods are used in the production and operation of printed circuit assemblies (PCA) for radio-electronic means (REM). The main methods are optical, electrical, and thermal. However, not all possible defects can be detected using these methods. For example, a weakened PCA fastener in a block or the incorrect installation of an electric radioelement (ERE) on a printed circuit board (PCB) can be detected only by analyzing the mechanical characteristics of the REM. These factors, in particular, are the values of the vibration acceleration amplitudes on ERE or at selected PCB control points (hereinafter referred to as the PCA vibration acceleration amplitude). In order to draw a conclusion about the presence of a defect, the measured values of the vibration acceleration amplitudes obtained as a result of testing PCA for the effects of harmonic vibration are compared with the permissible values calculated during the simulation of mechanical processes in PCA. This takes into account the variations in the physical and mechanical parameters of materials and geometric parameters of the PCA design. The aim of this paper is to determine the permissible values of PCA vibration acceleration amplitudes to be compared with the measured values.Methods. The Monte Carlo simulation method is used to calculate the permissible deviations of vibration accelerations. This consists in repeatedly calculating the values of the vibration acceleration amplitudes at random values of the physical and mechanical parameters of materials and geometric parameters of the PCA design within their tolerances.Results. Experimental verification of this method was carried out using the SolidWorks software for modeling mechanical processes. This enabled the tolerance values for PCA vibration acceleration at the control point at the first resonant frequency to be established and experimental data to be obtained when introducing various defects. The results of comparing the measured values with the calculated tolerance enabled conclusions to be made with regard to the possibility of detecting PCA defects.Conclusions. Using this method of calculating tolerances for the PCA vibration acceleration amplitude allows the presence of defects in REM that do not affect the electrical or thermal characteristics of REM to be determined, thus increasing the efficiency of technical condition control.

A review of soil pollution from LDPE mulching films and the consequences of the substitute biodegradable plastic on soil health

The plastic film mulching system has a significant role in increasing crop grain yields by changing the microenvironment of the plant. On the other hand, plastic mulching materials pollute the land and water because they are not degraded or disposed of properly. Biodegradable plastic mulches (BPM) may be used as a substitute for conventional low-density polyethylene (LDPE) to protect soil health. In this review, the effect of micro(nano)plastics on soil health and function has been discussed in light of their distribution in soil, changes in soil biochemistry, interactions between microplastics with soil microbes and plants, and their growth patterns. The nano-plastics are now incorporated into the food chain from the soil through plants and finally harm the whole ecosystem, including humans. The use of BPM has been practiced recently, but only 1% of the world’s total plastic production is from biodegradable materials. In the second part of the review, the confusing terms "bio-based" and "biodegradable" were clarified based on their polymeric constituents. The physical parameters of different constituent materials for mulching purposes and their capability for sustainable solarization have been discussed. The effect of biodegradable mulches on soil health and other ecotoxic effects on plants, soil microorganisms, and other soil dwellers like Daphnia magna, Vibrio fischeri bacteria, green algae, slime mould, protozoa, invertebrates like earthworms, and common water fleas have been focused on in this review. In conclusion, the use of BPM for mulching purposes was reported to improve crop quality and yield and reduce weed growth in comparison to naked soil. The recent short-term studies ensured that mulches stayed unbroken throughout the growing season. But simultaneously, the biodegradable mulches affect soil health and have a substantial impact on physical parameters such as soil pH, electrical conductivity, aggregate stability, infiltration, nitrate-N, exchangeable potassium, etc. Therefore, a lot of long-term research is required for the use of BPM as a substitute for conventional LDPE as a mulching film in the agricultural field.

Comparative assessment of physical and mechanical parameters of cast plastic material for the manufacture of bases of combined removable orthopedic structures

The urgent task of orthopedic dentistry is the timely and optimal restoration of chewing efficiency, with the creation of new and improvement of existing structural materials, optimization of the use of consumables and improvement of the clinical and technological stages of the manufacture of removable orthopedic structures. The purpose of our study was a comparative assessment of the physical and mechanical properties of cast plastic material for the manufacture of bases of combined removable orthopedic structures using an improved method. We have developed a new domestic material for the manufacture of the bases of removable dentures using foundry compression pressing technology. The following parameters of the study of physical and mechanical properties of plastics were taken into account: material Shore hardness, material consistency, relative deformation during compression, sorption, impact strength, bending stress, tensile strength, abrasion resistance, percentage of residual monomer. The comparative characterization of the physical and mechanical properties of cold polymerization acrylic plastics showed that domestic cold-cured base plastic for casting compression molding is not inferior to the foreign base in terms of its main indicators cold-hardening plastic differs from the analog cold-hardening base plastic by a harder and harder consistency, which makes it possible to more effectively use the material for combined bases of removable dentures. The obtained data indicate that, in general, the domestic material with its physical and mechanical properties meets the requirements for this class of dental materials. Keywords: orthopedic treatment, physical and mechanical properties, cast plastic material, method of compression pressing.

Seismic performance analysis of orthotropic shear walls based on the deformation energy decomposition method

Based on orthogonal completeness and mechanical equilibrium, the physical parameters of materials are further considered, and the deformation decomposition method is improved and applied to orthotropic structures. The method is realized by compiling ANSYS-MATLAB computer algorithms, and verified by strain energy analysis and experimental results. It not only quantitatively identifies tensile, compressive, bending and shear deformation energies of orthotropic structures, but also visualizes the regions dominated by the aforementioned fundamental deformation energies. Furthermore, the influence of the horizontal and vertical elastic modulus ratios of coupling beams and wall-columns on the seismic performance of orthotropic shear walls with different opening sizes is discussed. The results show that the ductility of the coupling beam and the wall-column is improved by appropriately reducing the horizontal and vertical elastic modulus ratio of the coupling beam, and the effect on the wall-column is weakened with the reduction of the opening size. But the lateral resistance of the shear wall is weakened. The wall-column ductility is improved by properly increasing the horizontal and vertical elastic modulus ratio of the wall-column, but the lateral resistance of the shear wall is weakened.

Calibration and verification of DEM parameters of wet-sticky feed raw materials

In order to improve the accuracy of the parameters needed in the discrete element method (DEM) simulation process of wet-sticky feed raw materials, the JKR contact model in DEM was used to calibrate and verify the physical parameters of wet-sticky feed raw materials. Firstly, the parameters that have a significant effect on the angle of repose were screened using a Plackett–Burman design, and the screened parameters were: MM rolling friction coefficient, MM static friction coefficient, and JKR surface energy. Then, the three screened parameters were selected as the influencing factors and the accumulation angle of repose was selected as evaluating indicator; thus, the performance optimization experiments were carried out with the quadratic orthogonal rotation design. Taking the experimentally measured angle of repose value of 54.25°as the target value, the significance parameters were optimized, and the optimal combination was obtained : MM rolling friction factor was 0.21, MM static friction factor was 0.51, and JKR surface energy was 0.65. Finally, the angle of repose and SPP tests were compared under the calibrated parameters. The results showed that the relative error of experimental and simulated tests in angle of repose was 0.57%, and the compression displacement and compression ratio of the experimental and simulated tests in SPP were 1.01% and 0.95%, respectively, which improved the reliability of the simulated results. The research findings provide a reference basis for simulation study and optimal design of related equipment for feed raw materials.

Classification of dissolution modes of partially protected poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solutions

The development of high-numerical aperture exposure tools for EUV lithography is in progress. The development process (the dissolution of resist films) is the key to fine patterning. The dissolution dynamics of acidic polymers (the backbone polymers of chemically amplified resists) depend on various parameters related to molecular structures. In this study, the dissolution dynamics in tetraalkylammonium hydroxide (TAAH) aqueous solutions were classified into six classes on the basis of the frequency and impedance changes observed during the development process by a quartz crystal microbalance method. The relationship between class and physical parameters of materials was analyzed by decision tree and support vector machine methods. The feature values used were the alkyl chain length, molecular weight, and concentration of TAAH; the viscosity of the developer; and the protection ratio, molecular weight, contact angle, surface free energies of polymers, and film thickness. The classification accuracy was 0.80 for the validation data.

TCAD Device Simulation of All-Polymer Solar Cells for Indoor Applications: Potential for Tandem vs. Single Junction Cells.

The utilization of indoor photovoltaics makes it feasible to harvest energy from artificial light sources. Although single-junction indoor photovoltaics have demonstrated exceptional efficacy when using LED lighting, there is still a need for more comprehensive testing of tandem structures. Herein, the first systematic TCAD simulation study on the potential for tandem all-polymer solar cells (all-PSCs) for indoor applications is provided. The presented all-PSCs are based on experimental work in which the top wide bandgap subcell comprises a polymer blend PM7:PIDT, while the bottom narrow bandgap subcell has a polymer blend PM6:PY-IT. Standalone and tandem cells are simulated under AM1.5G solar radiation, and the simulation results are compared with measurements to calibrate the physical models and material parameters revealing PCE values of 10.11%, 16.50%, and 17.58% for the front, rear, and tandem cells, respectively. Next, we assessed the performance characteristics of the three cells under a white LED environment for different color temperatures and light intensities. The results showed a superior performance of the front cell, while a deterioration in the performance was observed for the tandem cell, reflecting in a lower PCE of 16.22% at a color temperature of 2900 K. Thus, an optimized tandem for outdoor applications was not suitable for indoor conditions. In order to alleviate this issue, we propose designing the tandem for indoor lightening by an appropriate choice of thicknesses of the top and bottom absorber layers in order to achieve the current matching point. Reducing the top absorber thickness while slightly increasing the bottom thickness resulted in a higher PCE of 27.80% at 2900 K.

Thickness Measurement of Self-Lubricating Fabric Liner of Inner Ring of Sliding Bearings Using Spectral-Domain Optical Coherence Tomography

This study presents a novel and highly accurate method of measuring the geometric thickness of the self-lubricating fabric liner of bearings by combining the optical coherence tomography (OCT) technology and the Hanning-windowed energy centrobaric method (HnWECM). The geometric thickness of wear-resistant coating material is one of the important indicators for evaluating its wear, and the measurement of its geometric thickness is of great significance for preventing coating failure. To address the issue of significant measurement errors caused by using the refractive index of the sample instead of the group refractive index to calculate the material’s geometrical thickness in previous OCT research and applications, our proposed method can accurately measure the geometrical thickness of materials without the influence of the refractive index of the material. Moreover, this method exhibits the advantages of non-contact and high precision, since it utilizes an SD-OCT system, making it a novel method for extracting the physical parameters of composite materials. The geometric thickness of the peeled-off liner obtained from our method is compared with the thickness measured by the spiral micrometer to evaluate its accuracy. The experimental results indicate that the thickness measured by the spiral micrometer was 172 μm, while the maximum difference in the data obtained by our method was 171.261 μm. This suggests that the difference between the two methods is less than 0.430%, which verifies the accuracy and validity of our method. Additionally, the obtained geometric thickness and the optical thickness of the peeled-off liner are used to evaluate the group refractive index of this material. The inside geometrical structure of the self-lubricating fabric liner on the end face and inner ring of the sliding bearing is imaged with this group refractive index. The measurement of the inner ring liner of the sliding bearing proves the flexibility of the fiber-optic OCT and provides a non-contact, nondestructive testing method for measuring the geometric thickness and internal geometric structure of composite materials.

Thermomechanical instability of viscoelastic friction materials in automotive disk clutches and brake pads

The objective of this study is to develop a mathematical model to aid in predicting the onset of instability in automotive disk brakes and clutches when using viscoelastic friction materials. The model is derived from and expands upon the fundamental of Burton’s model for thermoelasticity in pure elastic materials. In this investigation, three physical material parameters are considered: relaxation time, elasticity, and thermal conductivity. Prior to this parametric study, the effects of these material properties in relation to thermoelasticity were yet to be fully understood. Therefore, a finite element analysis is developed and used to validate the mathematical model by comparing the variation of the critical speed as a function of thermal conductivity. The results reveal that an increase in the relaxation time significantly reduces the critical sliding speed. Changing the elastic parameter further increases the effect of relaxation time by also reducing the critical sliding speed. However, increasing the thermal conductivity parameter dampens the effect of the elastic parameter and relaxation time on the critical speed. The study concludes there is a critical value of the relaxation time and elastic parameter above which the system stability is improved, meanwhile thermal conductivity attempts to counter the stability gained from other material properties. The study is instrumental in understanding the influence of viscoelastic parameters in sliding systems and provides an intuitive means of predicting the onset of thermomechanical instability.

The Historic Materials and Structures Due to the Aspect of Their Actual Challenges

The subject of the article is to assess the suitability of over materials over a hundred years old that are embedded in historic building structures in conditions of contemporary utility challenges in residential and public buildings. It is based on an example of technical condition evaluation of a ceramic staircase erected in 1840 and a structure of two reinforced concrete staircases from the year 1910. As a part of in-situ and laboratory tests, the physical and mechanical parameters of unique historical materials (brick, concrete) were determined. Then the conditions for their incorporation were inventoried and determined in order to save the unique material and technical solutions used in the first half of the 19th century and the first decade of the 20th century. The article is a summary of the research and analyzes carried out in terms of proper handling of historical materials, buildings and their elements that could still fulfill their original function and be a witness to the history of a certain era. Both a research case and an application case are described here. It will allow for the continuation of these studies directly in the facility, thus assessing the effectiveness and suitability of such methods for use in similar or other situations. The aim of this approach was to introduce a non-invasive reinforcing technique that would not change the valuable and authentic appearance of these historic structures. It would also not change their static schemes, and at the same time would ensure their proper load-bearing capacity, bearing in mind that the materials used here are not equivalent to current regulations and standards.

Axial crushing of circular thin-walled specimens made of CFRP using progressive failure model (MAT54) in LS-Dyna

This research focuses on calibrating the MAT54 (ENHANCED_COMPOSITE_DAMAGE) material card in LS-Dyna for simulating axial crushing of circular thin-walled specimens made of CFRP. An IM7/8552 composite specimen showing the layup sequence of [902/±452/02]2 was simulated in LS-Dyna using shell elements. Following a trial-and-error-based method, the physical and non-physical input material parameters of MAT54 were calibrated. The calibrated input parameters included material strengths, failure strains, softening factors, and damping coefficient. The results of this study showed the applicability of the use of the physical material inputs from material characterization tests (e.g., tensile, in-plane shear, and compression) while showing the necessity of more in-depth calibration processes for the non-physical material inputs (e.g., viscous damping coefficient, crashfront reduction algorithm, etc.). The initial model predicted the specific energy absorption with an error of −57.95 % and this was improved by the calibration process to an error equal to −1.49 % for the final model. Now validated, the model will be used in the future to simulate impact into composite vehicle armor.

Similar ratio experiment and characteristic analysis of quasi-sandstone

The stability control of surrounding rock in deep roadway is becoming more and more difficult, and grouting reinforcement support has become the mainstream of roadway control. In order to obtain the ratio of quasi-sandstone material corresponding to the grouting body, this paper uses river sand as aggregate, cement and gypsum as cementing agent, retarder and defoamer as additives, and carries out orthogonal proportioning tests with three influencing factors: water-binder ratio (ratio of water to mass of cementing agent), gypsum-cement ratio (ratio of gypsum to mass of cement) and binder-aggregate ratio (ratio of cementing agent to aggregate mass), and compares and analyzes the sensitivity of each factor on the density, compressive strength, tensile strength, elastic modulus, Poisson’s ratio, longitudinal wave velocity, elasticity index and brittleness index of quasi-sandstone material. The results show that 1) the Water-binder ratio has the greatest effect on the sensitivity of material compressive strength, tensile strength, elastic modulus, Poisson’s ratio and longitudinal wave velocity; the gypsum-cement ratio has the greatest effect on the sensitivity of material deformation index and brittleness index; the binder-aggregate ratio has the greatest effect on the sensitivity of material density. 2) Reducing the Water-binder ratio can improve the density, compressive strength and tensile strength of the material; reducing the paste ratio can improve the modulus of elasticity, Poisson’s ratio and longitudinal wave speed of the material; as the gypsum-cement ratio increases, the deformation index first decreases and then increases and then decreases; as the binder-aggregate ratio increases, the brittleness index first increases and then decreases and then increases. 3) The empirical equations between physical and mechanical properties of sandstone-like materials and Water-binder ratio, gypsum-cement ratio and binder-aggregate ratio were established based on multiple linear regression analysis, and more reasonable material ratios were quickly obtained by physical and mechanical parameters of materials. The results of the study provide theoretical references for similar material simulation tests for quasi-sandstone grouting.

Thermal Properties Reconstruction and Temperature Fields in Asphalt Pavements: Inverse Problem and Optimisation Algorithms

A two-layer implicit difference scheme is employed in the present study to determine the temperature distribution in an asphalt pavement. The calculation of each layer only needs four iterations to achieve convergence. Furthermore, in order to improve the calculation accuracy a swarm intelligence optimization algorithm is also exploited to inversely analyze the laws by which the thermal physical parameters of the asphalt pavement materials change with temperature. Using the basic cuckoo and the gray wolf algorithms, an adaptive hybrid optimization algorithm is obtained and used to determine the relationship between the thermal diffusivity of two types of asphalt pavement materials and the temperature. As shown by the results, the prediction accuracy achievable with this approach is higher than that of the linear model.

Changes in the Basic Physical and Chemical Parameters of Raw Materials Under the Influence of the Milk-Protein Complex

Today, the development of competitive food products is of particular relevance. This focus should provide the population with high-quality meat products. A special role in this issue is given to non-traditional, national and innovative products, as well as products for healthy nutrition in the context of import substitution.

Determination of the surface properties and adsorption states of nanoporous materials using the zeta adsorption isotherm.

The adsorption process of porous materials has always been a popular field of research in interfacial physics, and the surface physical parameters of materials can be obtained from their adsorption characteristics, which has a great influence on the performance of materials. Based on the zeta adsorption isotherm, we propose a method based on the zeta adsorption isotherm to predict the entire adsorption process of porous materials and determine material surface properties from the measured isotherm data in the heterogeneity-free range. We applied the zeta constants of the silica adsorption system to the corresponding adsorption isotherm of the porous material. The results showed that the predicted adsorption isotherms are in good agreement with the experimental measurements before pore filling and can effectively identify the pressure ratios at the beginning and end of pore filling. In the region of high-pressure ratios, the Kelvin equation was utilized to calculate the pressure ratio at a contact angle of 0°. The surface parameters of the materials were determined by geometrically calculating the variation of the adsorption amount and the desorption isotherms in the high-pressure ratio range were calculated from these surface parameters. The predicted desorption isotherms can well reflect the adsorption process of silica porous materials in the region of a high-pressure ratio. In addition, for the surface parameters of the materials, the specific surface area calculated from the adsorption and desorption isotherms, respectively, differed by less than 7.9%, and the reliability of the method was verified by comparing the results with those of the argon adsorption systems.

Assessment of the stressed-strained state of a reinforced transport pipe under the combined effect of ambient temperature and static loads

The object of this study is a reinforced three-layer transport pipe, which is subjected to the joint action of ambient temperature and static loading of the road subgrade soil. The analytical model for assessing the stressed-strained state of reinforced three-layer pipes, under the combined action of temperature and static loads, has been improved using the theory of elasticity. The stressed-strained state of the reinforced pipe was assessed taking into account the values of the joint action of temperature and loads from vehicles, the physical and mechanical parameters of structural materials, and the geometric parameters of the pipe. As a result of the calculation of the reinforced multilayer pipe, it was found that the maximum movements that occur on the outside of the defective pipe are 0.64 mm, the metal pipe – 0.75 mm, and in the concrete mortar (fine-grained concrete) – 0.69 mm. It was established that under the combined action of ambient temperature and static loads from the road subgrade soil, ring stresses are maximum. They are 151 MPa. Axial stresses are also high – 141 MPa. At the same time, the maximum radial stresses are the smallest – 37.4 MPa. It has been established that a small difference in displacements occurs on the contact of structural materials of the reinforced pipe. However, the magnitude of the stresses is high. The maximum difference in ring stresses was 73 MPa, while the difference in radial and axial stresses was up to 1.0 MPa. It has been established that to restore the bearing capacity of damaged reinforced concrete pipes, it is possible to use the repair technology by the method of "sleeving". It involves pulling a metal pipe into the middle of the layer damaged with concrete mortar remaining between the concrete defective and the new metal pipes.