Integral Parameters Research Articles

An IGFBM-SAA Fast Algorithm for Solving Electromagnetic Scattering from Layered Media Rough Surfaces

This article proposes a new fast solution algorithm (IGFBM-SAA), which combines the Improved Generalized Forward and Backward Method (IGFBM) with Spectral Acceleration Approach (SAA), which can effectively solve the electromagnetic scattering problem of layered rough surface. In this article, the electric field integral equations (EFIE) for layered rough surfaces is established, and the traditional forward and backward method (FBM) is introduced. Then, based on the traditional FBM algorithm, an Improved Generalized Forward and Backward Method is proposed and, by using the SAA technique in its iterative process, the computation of matrix-vector multiplication is accelerated, thus enabling rapid solution. In the algorithm validation, the same rough surface was calculated using the MoM, FBM, and IGFBM-SAA. The study found that when root mean square (RMS) heights are h1=h2=0.1λ, the convergence accuracy can reach τ=10−7 after 14 iterations. However, as the roughness increases to h1=h2=0.3λ and h1=h2=0.5λ, the convergence accuracy falling to τ=10−5 and τ=10−5, respectively. This indicates that it is necessary to adjust the integration parameters to improve the convergence accuracy. In addition, it was found that when the size of the rough surface is 25.6λ, the computational times for calculations are 91 s (IGFBM-SAA), 197 s (FBM), and 410 s (MoM), respectively. When the size of the rough surface increases to 51.2λ, the computational time differences become more significant, with 236 s, 756 s, and 2547 s being the respective values. This indicates that the proposed algorithm in this article has significant computational speed advantages when dealing with larger rough surfaces. Based on this algorithm, this article studied the electromagnetic scattering characteristics of layered rough surfaces with different parameters (RMS height, dielectric constant, and correlation length), and relevant research results can provide valuable references for areas such as radar target recognition and radar stealth technology, thereby enhancing the accuracy and reliability of radar detection as well as radar stealthperformance.

Development of renewable energy fed three-level hybrid active filter for EV charging station load using Jaya grey wolf optimization

This work develops a hybrid active power filter (HAPF) in this article to operate in conjunction with the energy storage system (ESS), wind power generation system (WPGS), and solar energy system (SES). It employs three level shunt voltage source converters (VSC) connected to the DC-bus. Optimization of the gain values of the fractional-order proportional integral derivative controller (FOPIDC) and parameter values of the HAPF is achieved using the Jaya grey wolf hybrid algorithm (GWJA). The primary objectives of this study, aimed at enhancing power quality (PQ), include: (1) ensuring swift stabilization of DC link capacitor voltage (DCLCV); (2) reducing harmonics and improving power factor (PF); (3) maintaining satisfactory performance under different combinations of loads like EV charging load, non linear load and solar irradiation conditions. The proposed controller's performance is evaluated through three test scenarios featuring different load configurations and irradiation levels. Additionally, the HAPF is subjected to design using other optimization algorithms such as genetic algorithm (GA), particle swarm optimization (PSO), and ant colony optimization (ACO) to assess their respective contributions to PQ improvement.

On the application of numerical differentiation methods to the determination of the fatigue crack growth rate

Using a sample of test results from 68 compact eccentric tensile specimens made of titanium alloys, nickel alloys and steel, the effect of the choice of numerical differentiation method (secant method and the method of differential polynomials on three, five and seven points) used to calculate the fatigue crack growth rate on characteristics of the linear section of the kinetic diagram of the fatigue failure. The purpose of the study is to determine the advantages, disadvantages and consistent patterns of the considered methods. The coefficient of determination R 2, integral criterion χ which characterizes the difference between the predicted and actual number of cycles corresponding to the section of stable crack growth, and correlation between the logarithms of the Paris constants for alloys of the same class were used as criteria for the correct choice of the method of numerical differentiation. The main results and conclusions of the study: the use of the method of differential polynomials over three points compared to the secant method slightly increases the correlation between the logarithms of the fatigue crack growth rate and the range of the stress intensity factor (an increase in R 2) and increases the difference between the calculated and experimental number of cycles corresponding to stable crack growth (an increase in χ). However, when determining the fatigue crack growth rate by the method of differential polynomials for five and seven points, a more significant smoothing of the experimental data is observed, accompanied by a significant increase in R 2 and a decrease in χ; proximity to zero of the integral accuracy parameter χ is a necessary but not sufficient criterion for good agreement between the test result and the mathematical model that describes it, while the combination of parameters χ and R 2 uniquely forms this criterion; the choice of the method of numerical differentiation does not affect the correlation of the logarithms of the constants of the Paris equation.

Investigation of the Possibility of Using Turn-by-Turn Measurements to Detect Perturbations in the Magnetic Structure of Accelerators

The PCA correction method consists of a global analysis of turn-by-turn data obtained from beam position monitors (BPMs). One of its main advantages is speed of operation and the ability to detect pulsating power supplies. Along with this, a wide range of applications characterizes the PCA method: determination of perturbations of the accelerator magnetic structure, calculation of transport matrix elements and optical functions, and determination of the magnitude of the transverse coupling. A software prototype implementing the proposed correction method was written and tested on the electron-positron collider VEPP-4M for experimental validation. In the experiments, perturbations were introduced one by one into individual elements of the skew-quadrupole and quadrupole corrections. In one case, the excitation of betatron oscillations was carried out by the kick of the inflector. In another case, the oscillations were excited by resonant swing with a depolariser. It was found that, despite the simplicity of practical implementation, the examined method has some nuances that make it difficult to obtain and identify correct results. Nevertheless, it was possible to identify the introduced perturbations of quadrupole and skew-quadrupole corrections. Moreover, it was possible to detect a magnet with low-frequency pulsations by characteristic changes in the estimated invariants. In addition, the possibility of determining the integral coupling parameters in experiments on the observation of resonantly excited eigen modes having the shape of ellipses in the plane transverse to the beam motion axis is considered.

Numerical simulation and tool parameters optimization of aluminum alloy transmission intermediate shell

Due to its challenging manufacturing and intricate morphology, the aluminum alloy transmission intermediate shell used in vehicle transmission has been the focus of many academic studies. In this study, the three-dimensional cutting model is condensed to a two-dimensional cutting model and utilized to simulate the finishing process of an aluminum alloy workpiece using the finite element modeling program DEFORM-3D. Through orthogonal testing and range analysis, the impact of integral end mill side edge parameters on cutting performance was investigated. It is determined that tool chamfering has a greater impact on cutting performance than tool rake and relief angles, that chamfering width has the most impact on cutting force, and that chamfering angle has the greatest impact on cutting temperature. The workpiece's surface roughness is tested during a cutting experiment, and an analysis of the data reveals that the finite element simulation model is accurate and the orthogonal test method is reasonable. The tool chamfer has a greater impact on roughness than the tool rake angle and relief angle. The tool settings are further optimized using the firefly method. By examining the data, it is determined that the prediction model is correct and the optimization model is reasonable. The cutting efficiency is higher and the surface quality is better when the chamfer width is 0.17 mm and the chamfer angle is 7.3° or 18.3°. Therefore, optimizing the side edge parameters of the integral end mill during the finishing process of a thin-walled aluminum alloy shell has practical technical value.

Point-of-care and traditional erythrocyte sedimentation rate, point-of-care rheometry, and cell-free DNA concentration in dogs with or without systemic inflammation.

RBC aggregation and deformability characteristics are altered by inflammatory, microcirculatory, and hemorheologic disease. These changes can be indirectly evaluated using the erythrocyte sedimentation rate (ESR). Newer point-of-care devices employ syllectometry to evaluate RBC rheology, which can give information beyond the ESR. We evaluated 2 point-of-care rheometers (iSED and MIZAR; Alcor Scientific) in 52 dogs presented to a university teaching hospital. Whole blood samples were analyzed for correlation between the ESR using the Westergren (ESRw) method (measured at 1 h and 24 h) and the predicted ESR using iSED. Plasma fibrinogen and cell-free DNA concentrations were also measured as probable markers of inflammation. The iSED-predicted ESR was positively correlated to the ESRw method at 1 h (r = 0.74; p < 0.001) and 24 h (r = 0.62; p < 0.001). Comparing dogs with or without inflammation (defined as plasma fibrinogen concentration >3.5 g/L [350 mg/dL]), significant differences were seen in the MIZAR parameters of base point, amplitude, integral, and half-time. Median cell-free DNA concentrations were higher in the group of dogs with inflammation (117 [range: 51-266] ng/mL vs. 82.7 [range: 19-206] ng/mL; p = 0.024). The iSED-predicted ESR is a good predictor of the ESRw and was obtained more rapidly. Rheometric parameters measured by MIZAR may be useful in detecting inflammation and monitoring secondary morphologic and functional changes in canine RBCs.

Optimization of Proportional–Integral (PI) and Fractional-Order Proportional–Integral (FOPI) Parameters Using Particle Swarm Optimization/Genetic Algorithm (PSO/GA) in a DC/DC Converter for Improving the Performance of Proton-Exchange Membrane Fuel Cells

In this article, the control of a DC/DC converter was carried out using the proposed methods of conventional PI, PSO-based PI, PSO-based FOPI, GA-based PI, and GA-based FOPI controllers in order to improve the performance of PEMFCs. Simulink models of a PEMFC model with two inputs—hydrogen consumption and oxygen air flow—and with controllers were developed. Then, the outputs of a system based on conventional PI were compared with the proposed methods. IAE, ISTE, and ITAE were employed as fitness functions in optimization algorithms such as PSO and GA. Fitness function value, maximum overshoot, and rising time were utilized as metrics to compare the performance of the methods. PI and FOPI parameters were optimized with the proposed methods and the results were compared with traditional PI in which the optimum parameters were determined by an empirical approach. This research study indicates that the proposed methods perform better than the conventional PI method. However, it becomes apparent that the GA-FOPI approach outperforms the others. The simulation result also shows that the PEMFC model with conventional PI and FOPI controllers in which the controller parameters are tuned using PSO and GA has an acceptable control performance.

Motion-Based Wave Inference With Neural Networks: Transfer Learning From Numerical Simulation to Experimental Data

Abstract The directional wave spectrum, which describes the distribution of wave energy along frequencies and directions, can be estimated from the measured motions of a vessel subjected to a particular sea condition by resorting to the wave-buoy analogy. Several methods have been proposed to address the inverse estimation problem; recently, machine learning techniques have been assessed as further alternatives. However, it may be difficult to gather large datasets of in-service motion responses and the associated sea states to train effective data-driven models. In this work, an encoder–decoder neural network is trained with the synthetic responses of a station-keeping platform supply vessel (PSV) to estimate the directional wave spectrum. This estimation model is directly applied to perform wave inference from motion data of wave basin tests with a small-scale model of the same vessel. Furthermore, fine-tuning is also used to incorporate experimental data into the neural network model. Results show a satisfactory match between estimated and measured values, both with respect to the energy distribution and the integral spectrum parameters, indicating that the proposed approach can be employed to obtain data-driven wave inference models when there is little or no availability of measured motion records and the corresponding sea conditions.

Leveraging Technology Integration in Kenya's Food &amp; Beverage Industry for Competitiveness.

Leveraging Technology Integration in Kenya's Food &amp; Beverage Industry for Competitiveness.

Effect of various hesperidin and naringin addition levels on specific sperm indicators and the integrity of their DNA as measured by the comet assay in aged broiler breeder males

In broiler breeder males, the generation of semen decreases with age, and the body produces more free radicals when aging symptoms start to appear. Certain citrus wastes are a potentially sustainable source of high-biological value compounds with antioxidant properties that can enhance the performance of the male reproductive system. Hesperidin and naringin are two examples of these substances. Each treatment was given to the roosters separately, and their impacts on DNA integrity and semen parameters were later investigated using the comet assay. in contrast to the treatment used as the negative control. Most of the sperm characteristics (ejaculate volume, overall sperm motility, progressive sperm motility, sperm concentration, percentage of dead sperm, and percentage of abnormal sperm) were significantly and meaningfully improved by the hesperidin and naringin treatment. The percentage of genetic material that remains intact increased in the comet assay in favor of the treatments that also contained naringin and hesperidin. Finally, this study showed that hesperidin and naringin are sustainable substances led to improved semen qualities of elderly broiler breeder males and significantly increased the proportion of genetic material that was intact.

Experimental and numerical study of PMMA combustion in counterflow configuration

PMMA burning in counterflow has been studied experimentally and numerically. Thermal and chemical structure including concentrations of main species, i.e. ММА, O2, N2, CO2, CO and H2O, as well as an integral parameter (mass loss rate of a sample) were measured. The mathematical model is set in a coupled gas–solid formulation to resolve heat and mass transfer between gas-phase flame and thermally degrading solid combustible. Gas-phase combustion was modeled in the open-source Cantera software in a one-dimensional counterflow flame configuration. Governing equations of solid fuel was solved in an in-house code in two-dimensional formulation. Two chemical mechanisms of MMA oxidation (skeletal and detailed) were employed to resolve gas-phase combustion. Two sets of parameters of PMMA pyrolysis reaction were investigated. Gas phase temperature distribution was experimentally shown to be almost uniform in the direction parallel to the sample's burning surface in the area up to 4 mm from the sample's axis. The best agreement for macroscopic parameter, mass loss rate, was obtained by employing Lengelle pyrolysis kinetics, which is within 10 %. Total heat flux from gas-phase flame to the solid sample is about 23 kW/m2. Both gas-phase combustion mechanisms overpredict maximal temperature in flame by about 200 °C.

Methodology for the production of Ni-based open-cell metal foam using ultrasound-assisted electroplating

ABSTRACT Metal foam is a new type of metal that has a variety of uses because its properties can be customised to suit a specific need. Since it has the potential to replace traditional metals, it is important to explore the most advanced methods for creating foams with various levels of porosity. However, it is difficult to produce metal foam cost effectively while also achieving the desired properties due to the random structure and complexity of the process. Therefore, this manuscript outlines a step-by-step guide for creating Ni-based foam using electrodeposition, which overcomes these developmental challenges. Also, the manuscript discusses the characterisation of the foam’s integrity parameters at each stage, as well as the problems encountered during production and their solutions to optimise the developmental process. Finally, the manuscript presents mechanical testing results that demonstrate the foam’s compressive strength of 10.21 MPa at 80% length reduction, porosity of 92% and pressure drop through foam of 0.026% was reported. The developed foam can find usability in corrosive and high-temperature filtration systems, substantiated by mechanical testing results, that are also described.

Optical luminescent properties of eggs

Relevance. Optical photoluminescent properties of poultry eggs can serve as indicators of their quality both for incubation processes and for food technology processes. At the initial stage, it is important to evaluate the spectral characteristics of excitation and luminescence, as well as the parameters of table and incubation eggs of different quality and with different shell color.Methods. Chicken eggs of Chinese silk and Hysex brown crosses, as well as samples of duck, goose and quail eggs were used for research. The measurements were carried out on a diffraction spectrofluorimeter “Fluorat02-Panorama” with built-in software “Panorama Pro”. The obtained spectral characteristics were used to calculate the energy (integral absorption capacity and luminescence flux, spectrum energy) and statistical parameters (expectation, variance, asymmetry, kurtosis), as well as the Stokes shift.Results. Photoluminescent properties of poultry eggs are manifested in the ultraviolet region of the spectrum. Qualitatively, the spectra of different species of domestic birds are similar with a slight difference in the Stokes shift. For fertilized chicken eggs, the photoluminescence flux is 2.7 times greater than that of unfertilized eggs, while the spread of values for unfertilized eggs is 5.6 times less. Spectrum parameters such as asymmetry and kurtosis differ significantly for the luminescence of dark and light-shell chicken eggs. For table eggs, the integral energy parameters are 2.8–3.1 times greater than those of incubation eggs.

Mathematical formulae for neutron self-shielding properties of media in an isotropic neutron field

In the current study, an ab initio derivation of the neutron self-shielding factor to solve the complex neutron transport problem of the decrease of the neutron flux as it penetrates into a material placed in an isotropic neutron field having equal flux in all directions. The theory of steady-state neutron transport was employed, starting from Stuart’s formula, to derive simple analytical formulae based on the integral cross-section parameters. The formulae could be adopted by the user according to various variables, such as the neutron flux distribution and geometry of the simulation at hand. The concluded formulae of the self-shielding factors comprise an inverted sigmoid function normalized with a weight representing the ratio between the macroscopic total and scattering cross-sections of the medium. The general convex volume geometries are reduced to a set of chord lengths, while the neutron interaction probabilities within the volume are parameterized to the epithermal and thermal neutron energies. The arguments of the inverted-sigmoid function were derived from a simplified version of neutron transport formulation. The derived analytic formulae agreed greatly with the experimental observations for different elements and geometries.

Arap aygırlarında spermatolojik parametrelerin sezonun farklı dönemlerine göre değişimlerinin değerlendirilmesi

In this study, determining of the variations on spermatological characteristics of Arabian stallion semen in the different periods of the breeding season is aimed. The periods have been described as the beginning of the season (BS: 15th February – 15th March), mid-season (MS: 15th April – 15th May), and end of the season (ES: 30th May – 30th June). A total of 7 Arabian stallions that were 5-10 years old, with body condition scores between 3-3.5 and without any problems in terms of general and reproductive health, were enrolled in the study. In total, three semen samples were collected from each stallion, once in each period. Then, these samples were evaluated in terms of volume, concentration, total motility (TMOT), progressive motility (PMOT), viability, high mitochondrial membrane potential (HMMP), acrosome integrity (AI), capacitation index (Ci), and lipid peroxidation (LPO) parameters, which were analyzed by computer assisted sperm analysis and flowcytometry devices. As a result, the differences in volume, concentration, TMOT, and PMOT between the BS, MS, and ES periods were statistically insignificant (p&gt;0.05). The lowest viability values were determined in the BS period (p

A randomized controlled trial comparing different sites of high-velocity low amplitude thrust on sensorimotor integration parameters

Increasing evidence suggests that a high-velocity, low-amplitude (HVLA) thrust directed at a dysfunctional vertebral segment in people with subclinical spinal pain alters various neurophysiological measures, including somatosensory evoked potentials (SEPs). We hypothesized that an HVLA thrust applied to a clinician chosen vertebral segment based on clinical indicators of vertebral dysfunction, in short, segment considered as “relevant” would significantly reduce the N30 amplitude compared to an HVLA thrust applied to a predetermined vertebral segment not based on clinical indicators of vertebral dysfunction or segment considered as “non-relevant”. In this double-blinded, active-controlled, parallel-design study, 96 adults with recurrent mild neck pain, ache, or stiffness were randomly allocated to receiving a single thrust directed at either a segment considered as “relevant” or a segment considered as “non-relevant" in their upper cervical spine. SEPs of median nerve stimulation were recorded before and immediately after a single HVLA application delivered using an adjusting instrument (Activator). A linear mixed model was used to assess changes in the N30 amplitude. A significant interaction between the site of thrust delivery and session was found (F1,840 = 9.89, p < 0.002). Pairwise comparisons showed a significant immediate decrease in the N30 complex amplitude after the application of HVLA thrust to a segment considered “relevant” (− 16.76 ± 28.32%, p = 0.005). In contrast, no significant change was observed in the group that received HVLA thrust over a segment considered “non-relevant” (p = 0.757). Cervical HVLA thrust applied to the segment considered as “relevant” altered sensorimotor parameters, while cervical HVLA thrust over the segment considered as “non-relevant” did not. This finding supports the hypothesis that spinal site targeting of HVLA interventions is important when measuring neurophysiological responses. Further studies are needed to explore the potential clinical relevance of these findings.

A transformation method evaluate for near singular boundary integrals in the structural analysis of thin structure

The computational accuracy of near singular integrals is the key to determine the overall accuracy and stability of BEM in solving elastic variables, and even the success or failure of BEM analysis. In this paper, an alterative sinh transformation method is developed for solving the near singular boundary integrals in the structural analysis of thin structure. Firstly, the original sinh method is modified into the form include minimum distance and approximate expansion of local coordinates, and Newton-Raphson and cubic equation solving methods are used to obtain the position of the near singular projection point. To facilitate the implementation of the near singular integral, the integral element in the local coordinate space is mapped to the integral parameter space, and then the element integration is performed directly by sinh transformation in this space. The results of several numerical examples show that the proposed method can be used to regularize the nearly singular boundary integral effectively, and to accurately solve the elastic physical variables in the analysis of thin structures.

Honey Badger Algorithm Based PI Controller for DC Link Voltage Control of Solar Photovoltaic System Connected to Grid for Enhanced Power Quality

The parameters of the proportional integral (PI) controller used for DC link voltage control play a vital role in regulating the DC link voltage of grid-connected solar photovoltaic system that experiences heavy DC voltage fluctuation and various power quality issues due to integration of non-linear loads, varying irradiance and loading conditions. The existing strategies might fail to respond to the above complications due to fixed PI gains which restrict their scope of controlling domain. Therefore, adaptive PI gain values should be selected to quickly adjust to the varying conditions and dynamically obtain the optimal control settings. This article employs the honey badger algorithm (HBA), developed in Matlab to adaptively tune the PI controller gains value by minimizing the DC link voltage deviation. The advantages of using this technique over conventional PI controllers are its quick response, adaptability, stability, and optimal self-tuning process. The proposed algorithm has been tested under steady-state and dynamic conditions for different irradiation and loading conditions. Further, results of the proposed algorithm have been compared with PI controller and particle swarm optimization-PI controller to validate the efficacy of the proposed algorithm for grid-connected solar photovoltaic systems. It has been observed that the proposed algorithm maintains THD <3% in all the tested conditions.

Numerical modeling and experimental investigation on fatigue failure and contact fatigue life forecasting for 8620H gear

Surface integrity parameters exert an enormous function on contact fatigue performance of gears. In this paper, a gear contact fatigue life prediction model that incorporates surface integrity parameters is proposed. The micropitting and pitting damage of failed gears are quantitatively analyzed through micro-characterization techniques. A three-dimensional contact analysis of rough surface is performed to simulate the morphology evolution during gear running-in. And the coupling effect of residual stress and rough morphology on the contact stress field and fatigue life is analyzed. Finally, residual stress optimization design is carried out based on the failed gear. Gears subjected to shot peening are designed and gear contact fatigue tests under various working conditions are performed. The research results indicate that the plastic deformation at the asperities level in the running-in process mainly occurs during the initial loading. The fatigue life significantly increases by improving the residual stress distribution on the tooth surface through shot peening process. The maximum relative error between predicted fatigue life and measured fatigue life is less than 20%, which effectively verifies the accuracy of the proposed model. The technique presented in this study could provide theoretical basis and data support for the anti-fatigue design and manufacturing of gears.

Phase transitions, baro- and piezocaloric effects in single crystal and ceramics of ferroelectric NH4HSeO4

A study of heat capacity, thermal dilatation and sensitivity to hydrostatic and uniaxial pressure was carried out on single-crystal and ceramic samples of NH4HSeO4. The main parameters of low-temperature successive phase transitions B2 (T1) ↔ incommensurate IC (T2) ↔ ferroelectric P1 (T3) ↔ non-ferroelectric did not depend on the type of samples. The behavior of the volumetric strain and the results of direct measurements of T3(p) contributed to the resolution of the longstanding problem associated with the ambiguity of the sign of the corresponding volumetric baric coefficient. The role of thermal expansion anisotropy in the formation of the piezocaloric effect (PCE) near the ferroelectric phase transition at T3 has been studied. Due to the strong difference in the linear baric coefficients, the main contribution to the barocaloric effect (BCE) comes from the inverse intensive and extensive PCE associated with the a-axis. Compared to a single crystal, ceramics demonstrate lower BCE values, which, however, exist in a wider temperature range, which leads to close values of integral caloric parameters. The strong decrease in both BCE and PCE at low-temperature transformations in NH4HSeO4 compared to the ferroelectrics NH4HSO4 and NH4NH4SO4 is associated with a small change in entropy during three low-temperature phase transitions, ΣΔSi = 2.52 J/mol∙K, which is a consequence of a high degree of structural ordering in selenate as a result of a high-temperature transformation at T0 between the superionic and B2 phases, accompanied by a giant change in entropy, ΔS0≈Rln21.