Verification Of Concept Research Articles

Experimental verification of a common assumption in the use of concentration-dependent interdiffusion coefficient

There has generally been a view that concentration-dependent interdiffusion coefficient, D(C), obtained at any diffusion temperature and time is a material constant and can be reliably used to predict diffusion effects at all other isothermal diffusion times. This notion which is implicitly predicated on the assumption that diffusion-induced stress (DIS) rapidly and completely relaxes once formed and does not influence D(C) is experimentally verified in the present work. The results of the study show that reliably computed D(C) from concentration profile obtained at long diffusion time fails to correctly predict concentration profiles at shorter diffusion periods, due to isothermal variation of the D(C) with time. Accordingly, instead of continuing to assume that D(C) is time-independent and can be reliably used to predict diffusion effects at any isothermal diffusion time, without appropriate experimental support, proper experimental verification of this crucial concept in other alloy systems, as done in the present work, is imperative.

Student Organization Website with E-Voting Feature by Using Student Card Verification Concept Design

Student organizations hold an election to decide their next head and vice head every year. The best voting method for student organizations is to use an independent website with a voting system. The voting system can use students’ identity card and their student email as base for verification. OCR and face detection can be used for extracting all the needed information to validate the student card and verify it with the corresponding student email input. Other than the voting system, the website can be used to promote the student organization itself. The website was built using Nuxt for its front-end, Firebase for its back-end, and Cloud Vision API for its OCR and face detection module. There is a Lighthouse test, a stress test for the voting system, and a test to determine the optimal file size for the voting system. The results are a website that has an average Lighthouse score of 97.58. The stress test, which used a script that does submission repeatedly, results suggest that the voting system can handle up to 2000 voters at the same time. The optimal file size determined by the authors to be 500KB as the result of its test. The conclusions are a great performing website with a voting system can be built using Nuxt and Firebase, the voting system can be improved by adding another step of verification, and it’s best to use and image with a file size above 250KB when using Cloud Vision API for optimal results

Scaling procedure for on-ground testing of a robust attitude and vibration control architecture for a large flexible satellite

The agility of satellites equipped with large and flexible structures, such as solar panels or antennas, poses a significant challenge due to the influence of elastic dynamics on attitude motion. This results in reduced pointing accuracy and dimensional stability of the payload. To address this issue, an Active Collocated Attitude Control (ACAC) system has been developed, utilizing actuators for both the elastic dynamics (distributed piezoelectric devices) and attitude control (ON-OFF thrusters). In the initial phase of the project, the algorithm underwent extensive verification using a high-fidelity numerical model of a spacecraft with two very-low frequency flexible solar panels and a payload consisting of two long booms and a transversal antenna's reflector. The paper focuses on the second phase of the project, which revolves around the experimental verification of the control architecture concept. To achieve this, a scaling procedure employing the dynamic analogy approach was implemented to determine the design parameters of a free-floating platform equipped with elastic appendages. This ensured that the resulting elastic multibody system displayed similar dynamic behavior to the full-scale satellite. Based on the scaling parameters, a test rig was manufactured, and actuators and sensors were optimally positioned. The performance of the ACAC system was then compared to that of traditional benchmark controllers. The results show that the ACAC system demonstrates superior capabilities in performing fast slew maneuvers without developing unstable interactions with the elastic dynamics.

Tuning the thermo-mechanical synergies effect of solid oxide fuel cells with negative thermal expansion NdMnO3 in La0.6Sr0.4Co0.2Fe0.8O3-δ-based symmetric electrode

Solid oxide fuel cells (SOFCs) are efficient and clean energy conversion devices, but one of the major challenges for their marketization is the instability of different component materials under high temperature operating conditions. The existence of a certain internal stress gradient between materials with different thermal expansion characteristics in the process of SOFCs from low temperature assembly to high temperature use is the main reason of this instability, leading to the inability of SOFCs to repeat start-stop and the rapid decay of long-term stability performance. To improve these problems, a creative concept of fuel cell interface overall regulation is proposed, simplifying the complex interface between different components of SOFCs into a unified and adjustable quasi-zero difference thermal expansion interface. The composite of high catalytic activity electrode material and high stability negative thermal expansion material is used for electrolyte support structure symmetrical cell, which makes the whole cell “sandwich” structure thermally and mechanically compatible. As a concept verification, the classic high catalytic performance electrode material La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), Gd0.2Ce0.8O2-δ (GDC) and NdMnO3 (NM) negative thermal expansion material with high chemical stability and mechanical stability were composited in equal proportions to form LSCF@GDC&NM electrode as the symmetrical electrode. After equal proportion compositing, the thermal expansion curve of LSCF@GDC&NM material can highly coincide with the thermal expansion curve of GDC, making the single cell with LSCF@GDC&NM electrode can withstand 25 power thermal cycles without significant performance decay, achieving 442 mW cm−2 at 800 °C and maintaining stably for 140 h without any degradation. These results show that using negative thermal expansion material to regulate electrode strategy is expected to make a whole zero difference thermal fuel cell configuration.

Modulation Techniques and Coordinated Voltage Vector Distribution: Effects on Efficiency in Dual-Inverter Topology-Based Electric Drives

The increasing popularity of electric drives employing an isolated dual-inverter (DI) topology is motivated by their superior DC-link voltage and power utilization, fault-tolerant operation, and potential for multilevel operation. These attributes are significant in battery-powered transportation, such as electric vehicles and aviation. Given the considerable freedom in modulation and control of the DI topology, this paper researches the impact of reference voltage vector distribution between the two individual inverters. The study also evaluates the influence of two well-established asynchronous modulation strategies—Space Vector PWM (SVPWM) and Depenbrock’s Discontinuous Modulation (DPWM1). Since simulation tools nowadays play a crucial role in power electronics design and concept verification, the results are based on extensive and detailed models in Matlab/Simulink. Employing the basic field-oriented control of a 12 kW induction motor with precisely parameterized SiC switching devices for accurate loss calculation, this research reveals the possibility of significant energy savings at multiple operating points. Notably, optimal efficiency is achieved when one inverter operates up to half of the nominal speed while the other solely establishes a neutral point for the winding. Moreover, the results highlight DPWM1 as a superior strategy for the DI topology, showcasing reduced converter losses. Overall, it is shown that the system’s losses can be significantly reduced just by the design of the voltage vector distribution in the drive’s operating range and the modulation strategy selection.

НАУЧНО-МЕТОДИЧЕСКИЕ ОСНОВЫ ФОРМИРОВАНИЯ ЭКОЛОГО-ИССЛЕДОВАТЕЛЬСКИХ КОМПЕТЕНЦИЙ В ПОДГОТОВКЕ УЧИТЕЛЕЙ БИОЛОГИИ

The article addresses the issue of developing environmental research competence in the training of biology teachers at pedagogical universities. The new socio-cultural and ecological situation has significantly changed the role of the educator and the content of their activities in overcoming the ecological crisis, pushing the boundaries beyond professional subject competencies, increasing their responsibility for the results of environmental education of the younger generation, and necessitating the formation of new professional competencies in the field of education. The goals and objectives of the study are to form environmental research competencies in the training of biology teachers by identifying significant shortcomings of the traditional system of ecological-pedagogical education, comparing results, and solving the problem of developing the competencies under study through innovative practices of professional training of future specialists. The authors used cluster analysis in forming the environmental research competencies of students. The problem of forming competencies can be solved both through innovative practices of professional training of future specialists and through scientific support of various pedagogical concepts, theories, approaches. The analysis of the study results allowed identifying significant shortcomings of the traditional ecological-pedagogical education system in solving the problems of development and formation of environmental research competencies during university education. The experimental verification of the competence formation concept confirmed its main provisions and allowed determining the main conditions for its successful implementation.

Materialkorrosion und Alterung von zementgebundenen Beschichtungen in der Trinkwasserspeicherung

AbstractIn order to ensure durability, mineral coatings in drinking water storage must be sufficiently resistant to chemical and physical influences. The effects are described in the DVGW W 300 worksheets. This results in requirements for the composition, the mechanical properties, the bond strength, the minimum layer thickness, the surface quality and the impermeability of the mineral coatings.Durability is currently ensured descriptively based on the applicable set of standards. This verification concept reaches its limits when the normatively secured area of experience is left behind using new binding agents. A number of performance‐oriented test concepts have been developed in recent years for the durability assessment, with which a quantitative assessment of the durability is made possible, taking into account the damage processes and the effects to be expected.The course of the leaching kinetics can be described with a diffusion‐erosion model and corresponds to a diffusion‐controlled process with a √t course and a linear course with an unchanged top layer. Once the linear damage process has been reached, an estimate of the remaining service life is possible. A model for durability assessment based on diffusion‐erosion processes is presented.

Direct spatio-temporal stress field determination combining full-field deformation measurements and explicit finite element method: Concept verification

High strain rate loading of materials with spatially heterogeneous properties produces non-homogeneous and transient stress-strain states. Such stress-strain states are atypical of classical split Hopkinson pressure bar (SHPB) analysis that assumes homogeneous deformation and dynamic force equilibrium. To determine spatio-temporal stress fields in heterogeneous materials, a novel concept combining digital image correlation (DIC) full-field deformation measurements and explicit dynamic finite element method (EFEM) is described in this paper. The concept utilizes measured boundary forces and DIC measurements including both displacements and accelerations as input. The measured input is used to calculate internal forces, and hence the stress fields, within each continuum finite element by solving the governing equations of motion using the framework of EFEM. The DIC+EFEM concept procedure is verified using simulated synthetic data considering one-dimensional stress wave propagation in a bar. The reconstructed axial stress fields match identically with the exact EFEM solution for both homogeneous and heterogeneous materials that are elastic or elastic-plastic. The influence of DIC measurement noise on the reconstructed stresses is also studied.

Alfred Jules Ayer’s Logical Positivism: A Critical Examination and Its Relevance in Islamic Studies

This article delves into the philosophical ideas of Alfred Jules Ayer, specifically focusing on his contributions to logical positivism. The research methodology employed is a literature review, utilizing a descriptive-analytical qualitative approach. The study is structured around four key aspects. Firstly, it provides an overview of the historical evolution of logical positivism. Secondly, it elucidates the theoretical framework of Alfred Jules Ayer’s logical positivism. Thirdly, it explores the criticisms leveled by Karl Popper against Ayer’s logical positivism, particularly concerning induction and verification. Lastly, the article investigates the relevance of Ayer’s concept of verification to the field of Islamic studies. The study concludes by discussing the applicability of Ayer’s verification concept to Islamic studies, drawing parallels with the concept of “tabayyun” in Islamic jurisprudence. “Tabayyun” signifies the meticulous scrutiny and verification of information, particularly when it originates from an untrustworthy source (a “fasiq”). This process aligns with Ayer’s emphasis on verifying meaningful propositions, ensuring the quest for clear truths in both philosophy and Islamic jurisprudence

Fatigue Verification Concept for Details containing Weld Imperfections

AbstractSteel structures subjected to repeated stress variations must be verified against fatigue in accordance with EN 1993‐1‐9 on the basis of a detail catalog. As one major concern, the background of the detail classification in terms of an extensive database does not provide information on the considered quality of welds. Certain weld imperfections are present in every construction. However, the extent of imperfection sizes that can be tolerated to provide sufficient fatigue resistance has not yet been scientifically determined.On an experimental and numerical basis, the presented concept allows the quantitative connection of fatigue classes with sizes of weld imperfections. For the two representative details of the load‐carrying‐cruciform joint and the non‐load‐carrying transverse stiffener, basic fatigue classes without explicit imperfections are calculated first. Furthermore, stress increase factors were determined that indicate the decrease in fatigue strength for weld imperfections of different type and size.A combination model is used to determine the fatigue strength of a detail with multiple weld imperfections. Using a simple formula and reading fatigue classes and reduction factors in tables, the fatigue strength of an imperfect detail can be easily determined.

Three Parts Modulation and Hybrid DC Capacitor Voltage Balancing for a Single-Phase Two-Leg Five-Level NPC Inverter

Capacitor voltage unbalance in NPC multilevel inverters is an inherent challenge and has a severe effect on five and higher-level inverters. Current modulation-based voltage balancing schemes for five-level NPC inverters require a high number of switching, especially at high modulation index operations. Moreover, hardware-based voltage balancing techniques come with a high component count. This paper proposes a unique three-part modulation technique combined with a hybrid voltage balancing approach to reduce switching losses and maintain voltage balancing. The modulation is composed of different carrier-based modulations, while the hybrid balancing scheme combines modulation-based and hardware-based balancing techniques. Comparative switching loss analysis demonstrates a reduction in inverter switching associated with the modulation. While the voltage unbalance characteristics of the modulation are determined considering linear loading conditions. Furthermore, balancing capacity analysis and switching loss reevaluation are used to justify the hybrid balancing performance. The concept verification use Matlab-Simulink simulation and hardware experiments on a five-level single-phase NPC inverter setup operated at different modulation index and power factor conditions.

Multichannel valley topological beam splitter based on different types of domain walls

Topological photonics has made great progress from physical concept verification to new technical applications, and valley topological photonic crystal (TPCs) are one of the most important candidates for future applications in functional devices because of large bandwidth and lossless optical transport. However, due to the limitations of the design method and structure arrangement, the multichannel valley topological beam splitter (BS) has not yet been much explored. Here, we reveal the different robustness of four types of domain walls in valley TPCs. Benefiting from the differences in domain walls, we numerically present and experimentally demonstrate a highly integrated multichannel valley topological BS in the microwave regime. Compared with traditional BSs, it has the advantages of being more robust and compact and having more output ports and higher integration. The reported multichannel topological BS opens an avenue to engineer the flow of light and offers effective design approaches for integrated photonic device miniaturization.

Induction Heating of a Fluidized Pebble Bed: Numerical and Experimental Analysis

The development of energy-efficient Power-to-Heat (PtH) technologies with high power density on a utility scale is a key element in the future of flexible energy systems. Although existing solutions for electric flow heaters (EFH) based on resistance heating have a high efficiency, the process outlet temperature and power output are limited by the lifetime of the contact heating elements. Inductively heated packed bed heaters can achieve higher gas outlet temperatures with a higher power density, which is essential for an efficient process. This paper focuses on the modeling, experimental validation and numerical analysis of inductively heated pebble bed gas heater. Foremost, a model that is based on a 3D finite volume method approach is introduced. After that, an experimental setup for different sphere arrangements is used to obtain results for concept verification and model validation. With the model validated, the design space for the PtH concept is investigated by varying the heat transfer area and material properties of the pebble bed. Design solutions with high energy efficiency above 90% and power density over 5.5 MW/m3 are presented for magnetic as well as non-magnetic materials at laboratory and utility scale.

Early Microjet Experimentation with Liquid Water in Vacuum.

ConspectusIn this brief look at the history of liquid microjets, I recollect some personal reminiscences on initial challenges for introduction of this method, as well as unexpected problems and exemplary results using this new tool for liquid evaporation and photoelectron spectroscopy studies.Many efficient and direct, atomic level diagnostic instruments in use at solid state surfaces and in gas-phase atom or cluster studies require high vacuum. They have therefore not been applied to investigations of aqueous solutions because liquid water both strongly evaporates and rapidly freezes in vacuum. Only fairly recently, over the past three decades, have liquid microjets been considered as practicable targets for research on liquid-water interfaces in vacuum. The working principle is analogous to the functioning of a free molecular beam source, where molecules enter through a small aperture into a vacuum without being disturbed by subsequent collisions in their original Maxwellian velocity distribution. Similarly, above a microjet surface in vacuum, water vapor molecules do not interact with each other, or with different probe particles, as long as the liquid jet diameter is small in relation to the mean free path of the liquids' vapor at equilibrium conditions. For pure liquid water, this constraint is Djet < λvap < 10 μm for 6.1 mbar vapor pressure at the triple point of water. A high streaming velocity of the liquid jet, >50 m/s, delays freezing and exposes a steadily renewed fresh vacuum surface for experiments.For experimental verification of the microjet free surface concept, H2O vapor velocities were measured in a molecular beam time-of-flight experiment. These studies showed Maxwellian velocity distributions with the expected local water-jet temperatures for 5 and 10 μm jets, whereas larger liquid jet diameters of 50 μm exhibit narrowed vapor velocity profiles. This narrowing is the known signature of incipient, collision dominated, supersonic hydrodynamic expansions in nozzle beam sources. As a completely unexpected new result in evaporation studies of carboxylic acid solutions, freely evaporating acetic acid dimers showed apparent non-equilibrium liquid surface source temperatures several hundred kelvin above the simultaneously measured monomer temperatures, a phenomenon shown to be correlated with surface tension.Continuing with improvements, the vacuum water microjets were implemented inside a photoelectron spectroscopy apparatus that was modified for handling large amounts of water vapor. After initial complications with liquid jet charging phenomena, the first partial liquid-water photoelectron spectra were recorded using 21 eV photons from a He I discharge lamp. In the next step, the equipment was taken to a synchrotron radiation beamline at BESSY II, resulting in substantial improvements of signal intensity and in photon tunability for narrow band monochromatic soft X-rays up to 1 keV. Two early examples of these continuing experiments are considered, briefly, for aqueous alkali halide salt solutions and for the pH-value dependent protonation of an NH2/NH3+ group in an amino acid directly in a photoelectron spectrum of a solution.In conclusion, liquid microjets have opened up a completely new approach to studies of arbitrary liquids with chemical and biological relevance.

Empirical verification of the regional leadership concept on the example of rising powers

In the domestic and foreign scientific literature, a consensus has appeared on the identification of the rising state’s status as a regional power. Most often, the BRICS countries are being identified as rising states. In recent years, publications identified the MIKTA countries as rising middle powers that already have the status of regional powers or tend to be such. The purpose of the article is to determine whether participation in the BRICS and MIKTA formats allows states to strengthen their regional leadership or claim regional leadership. As a part of the empirical study the regional leadership of the BRICS and MIKTA states, on the one hand, is being considered from the point of assessing the material power attributes throughout the use of the Composite Index of National Capability; оn the other hand, we proceed from a constructivist approach to the leadership concept. This approach allows us to consider leadership as a constructed category depending on the recognition by powers of a different order as belonging to the region, the legitimacy of the regional leader status for one or another state of the BRICS and MIKTA. Methodologically we proceed from the fact that the category of legitimacy can be operationalized by identifying the cohesion of voting in the UN General Assembly of the BRICS and MIKTA states with the states belonging to their regions. The top numbers of the similarity index average value indicate the recognition of the regional leadership of the BRICS and MIKTA member states by the follower states belonging to their regions. At the level of the hypothesis, it is expected that the average values of the similarity index, firstly, will be equal for the BRICS countries and the MIKTA countries, and secondly, they will be set to top values. Thus, this article is to determine the correlation between the resource endowment of the state’s regional leadership and the legitimacy of such leadership.

Numerical verification of the calorimeter concept for determining the calorific value of unidentified gaseous fuels

Measurement of the calorific value of fuels with the use of the present calorimeter structures requires specific conditions and takes a relatively long time. These requirements are related to the assurance of appropriate environmental parameters, i.e. temperature, air humidity in the room within a narrow range of variability, which means there is a need to require ensuring laboratory conditions for the measurement. This situation is closely related to the complicated measurement methodology. Therefore, taking into account these problems, the market need has been defined resulting from the specificity of the operation of industrial installations, in which it is important to evaluate the quality of the consumed or produced gaseous fuel. This article presents an innovative concept of a calorimeter designed to determine the calorific value of gaseous fuels, and also describes a mathematical model of the device made in the SciLab environment, which is the basis for further considerations.

Marketing data security and privacy protection based on federated gamma in cloud computing environment

This study aims to address the existing data security and user privacy vulnerabilities in the “cloud” environment, which is essential for ensuring the safety and integrity of data in the era of big data and cloud computing. To achieve this purpose, we propose a novel approach that combines the logit link function with a longitudinal joint learning framework for the gamma regression model. This approach enhances the application of the model and the loss function, providing a robust solution for data security and user privacy in cloud-based systems. While cloud computing technology has greatly improved the convenience of work and life, it has also introduced significant challenges related to data security and user privacy. This study leverages semantic web technology and blockchain technology to establish a distributed and credit-guaranteed product quality and safety traceability application. By designing a concept verification system and ensuring data integrity at each stage of the product supply chain, this approach addresses these challenges effectively. The distributed network architecture employed in our technical design ensures overall system stability, reliability, and sustainability, with no single point of failure.

Lembar Kerja Laboratorium Berbasis Proyek Pembuatan Koloid dengan Pemanfaatan Daun Cincau Perdu (Premna Oblongifolia)

Chemistry practicum is still only concept verification or is a cookbook.This study aims to develop student worksheets on producing jelly as a colloid product by using perdu cincau leaves (Premna Oblongifolia). The method used in this study is development research with ADDIE models (Analysis, Design, Development, Implementation, Evaluation), which only done until development step. Analysis curricula of colloid topic and study of literature on project-based practicum and perdu cincau leaves have been carried out at analysis step. At this step also interviewed high school teachers and found that there is no student worksheets for supporting KD 4.15. At design step, the experiment of jelly producing using perdu cincau leaves was optimized and the best laboratory work design was obtained, such as materials, tools and procedures. Then, a project-based laboratory worksheet draft was created and validated by experts. Based on the suggestions given by the validator, content number 11 was omitted because it contained irrelevant instructions. Content number 2 added instructions. Content number 15 and 16 an explanation is added. Content number 3, 4 and 12, it is necessary to edit sentences. After revising, student worksheets is ready to be implemented in learning activities.

Verification of the master curve concept (ASTM E1921) and inhomogeneity analysis of a German RPV weld for various loading rates

Fracture-mechanical investigations were carried out on the weld metal of a German reactor pressure vessel steel 22NiMoCr3-7. The crack tip loading rate and test temperature were varied in the brittle-ductile transition region, while the results were evaluated using the Master Curve methodology (ASTME1921), including inhomogeneity analyses in Appendix X5. The highly inhomogeneous datasets could be uniformly described with a bimodal distribution function with good accuracy compared to the standard procedure. However, this agreement decreases with increasing crack tip loading rate. In contrast, a modified Master Curve with a shape factor of p = 0.03/°C progressively matches the data better with increasing crack tip loading rate. The weld metal has a significantly higher toughness than the base material. SEM analysis suggests that the inhomogeneity is due to the stochastic distribution of sharp microcracks, while the observed inhomogeneity is additionally superimposed by dynamic effects (adiabatic heating and local crack arrest) at increased crack tip loading rates. It is argued that the microstructural inhomogeneity is hereby »neutralized« and could instead be interpreted as a possible artifact of the standard Master Curve under dynamic conditions.

Critical verification of the effective diffusion concept

Knowing the hydrogen distribution c(x,t) and local hydrogen concentration gradients grad(c) in ferritic steel components is crucial with respect to hydrogen embrittlement. Basically, hydrogen is absorbed from corrosive or gaseous environments via the surface and diffuses through interstitial lattice sites into bulk. Although, the lattice diffusion coefficient DL∼0.01mm2/s is in the order of magnitude of those for well-annealed pure iron, trapping sites in the microstructure retard the long-range chemical diffusion jL=−Dchem(c)grad(c), causing local hydrogen accumulation in near surface regions in limited time. Considering pure ferritic crystals without trapping sites in the microstructure, the limited characteristic diffusion depth xc∼Defft is proportional to the square root of the effective diffusion coefficient Deff and of time t. Effective diffusion coefficients are measured independently for hydrogen using the electrochemical permeation technique. For pure crystals, the effective diffusion coefficient is constant at given temperature and allows accurate calculations of the diffusion depths. However, with trapping sites in the microstructure the effective diffusion coefficient is not a material property anymore and becomes dependent on the hydrogen charging conditions. In the present work, the theory of hydrogen bulk diffusion is used to verify the concept of effective diffusion. For that purpose, the generalized bulk diffusion equation was solved numerically by using the finite difference method (FDM). The implementation was checked using analytical solutions and a comprehensive convergence study was done to avoid mesh and time dependency of the results. It is shown that effective diffusion coefficients can vary by magnitudes depending on the sub-surface lattice concentration. This limits the application of the effective diffusion concept and also the calculation of the characteristic diffusion depth.