Current Solution Research Articles

Analytic Solution for Buckling Problem of Rectangular Thin Plates Supported by Four Corners with Four Edges Free Based on the Symplectic Superposition Method

The buckling behavior of rectangular thin plates, which are supported at their four corner points with four edges free, is a matter of great concern in the field of plate and shell mechanics. Nevertheless, the complexities arising from the boundary conditions and governing equations present a formidable obstacle to the attainment of analytical solutions for these problems. Despite the availability of various approximate/numerical methods for addressing these challenges, the literature lacks accurate analytic solutions. In this study, we employ the symplectic superposition method, a recently developed method, to effectively analyze the buckling problem of rectangular thin plates analytically. These plates have four supported corners and four free edges. To achieve this, the problem is divided into two sub-problems and solve them separately using variable separation and symplectic eigen expansion, leading to analytical solutions. Finally, we obtain the resolution to the initial issue by superposing the sub-problems. The current solution method can be regarded as a logical, analytical, and rational approach as it begins with the basic governing equation and is systematically derived without assuming the forms of the solutions. To examine various aspect ratios and in-plane load ratios of rectangular thin plates, which are supported at their four corner points with four edges free, we provide numerical examples that demonstrate the buckling loads and typical buckling mode shapes.

Enhancing the engineering properties of gypseous soils by adding the Anthan polymers

Large areas of soil in Iraq are formed up of gypsum soil. As a result, understanding the habits of this soil and its treatment approach is critical, because its current solution is to replace gypsum soil before beginning any building activity. This study used gypsum soil from Tikrit City, which has a gypsum concentration that is around 38%, and the goal of the study is to illustrate the impact of the polymer on the gypsum soil parameters. Simultaneously, researchers are investigating the beneficial effects of polymers on the behavior of gypsum soil. The percentages of the polymer additive (5%, 7.5%, 10%, 12.5%, and 15%) were weight percentages, while the soil tests were chemical, physical, and engineering. When the percentage of additive was increased from 0% to 15%, Soil engineering characteristics enhanced the collapse of the from 5.11 to 1.21, cohesion improved from (28.98 KN/m2) to (51.16 KN/m2), and angles of internal friction decreased from 33.190 to 38.850.

Utilizing the L-curve criterion for the inverse magnetostatic problem of Hall drift current estimation

Aiming at achieving the in-orbit diagnostic of Hall drift current, this study focuses on estimation through the indirect measurement methodology using a magnetic sensor array. It elaborates on the application of a pseudo-seminorm defined for the Hall drift current solution to address the inverse magnetostatic problems, which are formulated with a two-dimensional Tikhonov regularization constraint, and thereby offering a systematic approach to select regularization parameters. Our investigation discusses factors influencing the formation of the L-curve and the accuracy of the resultant solution obtained via the L-curve criterion. The results reveal that the formation of the defined pseudo-seminorm of the Hall drift current solution in the semi-logarithmic coordinate system is independent of the number of calibrating current elements or the number of magnetic sensors. This effectively resolves the issue of failing to generate an L-curve during regularization parameter selection. Furthermore, the study indicates that expanding the number of calibrating current elements—essentially increasing the unknown variables in the inverse magnetostatic equations—contributes to a significant enhancement in the accuracy of Hall drift current solutions. It also has extensibility to be applied to other areas where the contactless current measuring is required.

Analysis of working face stability of longitudinally inclined shield driven tunnels in frictional soils

The shield machine has the advantage of reaching the predetermined depth more quickly with an inclination angle α, compared to conventional horizontal excavation. This paper aims to investigate the working face stability of shield tunnel driven with an inclination angle. An improved model is proposed by incorporating α into the traditional silo-wedge model. In this model, the contribution of the pressure of the cuttings in the excavation chamber on the working face stability is considered for both cases of α > 0 and α < 0. The optimization result is derived by applying limit equilibrium theory. A series of analyses reveal that the proposed model is predominantly influenced by the frictional angle and cover depth than by cohesion. The working face pressure increases linearly with the increase of α. In order to access the validity of the proposed model, the working face pressure and failure zone calculated by the proposed model are verified with numerical solutions and existing theoretical solutions. The current solution presents a more conservative result than other solutions in the case of α > 0, while predicts a smaller yet more reliable in the case of α < 0. Finally, two previous 1-g model tests with α = 15° and α = -15° are chosen to verify the proposed solution, where demonstrate a great consistence in limit working face pressure and the corresponding failure pattern.

Nonlinear periodic response of viscoelastic laminated composite plates using shooting technique

The nonlinear periodic response of viscoelastic laminated composite plates subjected to harmonic excitation is carried out in time domain using the generalized Maxwell model in the form of a Boltzmann integral. The integral form of the viscoelastic constitutive relation is converted to the incremental form for the finite element formulation based on the Reissner–Mindlin plate theory incorporating von Karman geometric nonlinearity. The recursive relations are developed to compute the current time-step solution using only the previous time-step solution. The periodic response is obtained using shooting technique coupled with Newmark’s time integration and arc length continuation method. The implementation of the shooting technique for the Boltzmann Integral based viscoelasticity done for the first time in this study involves derivation of a number of additional recursive relations and initial conditions at the beginning of each shooting cycle. The nonlinear periodic vibration characteristics such as frequency response, damping factor, steady-state response history, phase plane plots, and frequency spectra are presented for viscoelastic plates with different boundary conditions and lamination schemes. Further, the influence of relaxation time and number of Maxwell elements on the frequency response characteristics are investigated. It is seen that the shooting technique is capable of predicting periodic responses of viscoelastic dynamical systems directly from the second-order equations of motion and is more efficient than the direct time integration method. The nonlinear response of viscoelastic plates predicted using the equivalent elastic model with Rayleigh proportional damping (having same linear frequency response) is found to be significantly different from the one predicted using viscoelastic constitutive model.

Public Personnel in Terms of Current Problems and Solution Suggestions in the Turkish Administrative System

Kamu kurum veya kuruluşlarda, kamusal mal veya hizmetin ifasında bulunmak üzere, kendine özgü mevzuata uygun olarak görevlendirilen kamu personeli, idari sistemin de önemli bir parçasını oluşturmaktadır. Ancak bir taraftan kurumun insan kaynağı olarak, bir taraftan da kamu hizmeti ve yararına çalışan olarak yönetiminde karşılaşılan çeşitli sorunlar olabilmektedir. Bu genellemeye, Türk idare sistemine özgü durumların da etkisini katmak gerekir. Buna göre çalışmanın amacı Türk kamu personelinin yönetiminde yapısal sorunların yanı sıra, hukuki ve uygulama sorunlarının belirlenmesi ve çözüm önerilerinin sunulmasıdır. Ancak bu sorunları Devlet memuru, işçi ve sözleşmeli personel statülerine göre de gruplandırabilmek mümkün olmakla birlikte çalışmada, Türk kamu personeli toplamı içinde önemli bir çoğunluğa sahip olan Devlet memurlarına ilişkin sorunlar üzerinde durulmuştur. Dolayısıyla mevzuat olarak ta Devlet Memurları Kanunu esas alınmıştır. Bununla birlikte uygulamada karşılaşılan sorunlar incelenirken, diğer personele ilişkin bilgiler de verilmiştir. Çalışmada yöntem olarak konuyla ilgili bilimsel eserler taranmış ve ilgili mevzuat incelenmiştir. Buna göre Türk kamu personeline ilişkin sorunlar, personel yönetim ilkeleri, sınıflandırma ve istihdamdan başlayıp, ücretleme, ödülleme, yükselme ile hak ve yükümlülüklere kadar genişletilebilmektedir. Bu sorunlara ilişkin çözüm önerileri de bu konulara göre yapılmış, en uygun ve en uygulanabilir olanlar tercih edilmiştir.

An Integrated TMR-based Current Sensing Solution for WBG Power Modules and Converters

An Integrated TMR-based Current Sensing Solution for WBG Power Modules and Converters

Removal of Crystal Violet Dye by Electrocoagulation – Analysis of Electrode and Solution Changes

This study investigates the changes at the electrodes and in the solution during crystal violet dye removal by electrocoagulation at different current densities (0.016, 0.024, and 0.032 A cm&amp;lt;sup&amp;gt;–2&amp;lt;/sup&amp;gt;) and initial pH values (3.2, 5.5, and 7.0). The electrocoagulation process, which lasted 50 min, revealed changes in pH, temperature, electrical conductivity, and concentration of the crystal violet dye in the solution. The results demonstrate complete removal of crystal violet dye at the highest current density (achieved after 40 min) and an initial pH of 5.5 (complete removal after 30 min). During the electrocoagulation process, both the anodic and cathodic electrode materials were consumed. The consumption of electrode material increased with higher current density and solution pH, the influence of current density being more pronounced. Examination of the electrode surfaces under a light microscope revealed that the anodes dissolved uniformly and locally during the electrocoagulation process, while the cathodes mostly underwent uniform corrosion.

Research on location-routing optimization of distribution center for emergency supplies based on IMOCS-LNS hybrid algorithm

This paper establishes a location-routing optimization model of the distribution center for emergency supplies with the goals of system reaction time, total cost of consumption, psychological fear of the populace in disaster-affected locations, and material usage rate. Where the excess time, demand, and penalty coefficient are the components of the penalty cost in the total consumption cost, and where the psychological panic of those in the affected area is represented by the psychological perception function of panic developed in accordance with the prospect theory. An improved hybrid multi-objective cuckoo-large-neighborhood search algorithm was then designed to introduce tent mapping, nonlinear inertia weights, elite strategies, congestion operators, and dynamically adjusted discovery probabilities into the standard multi-objective cuckoo optimization algorithm, which generates a new solution using a large-neighborhood search algorithm after discarding part of the solution with the discovery probability, and then accepts the current nondominated solution with dynamic probabilities. The paper uses the improved algorithm to solve Christofides69, an arithmetic example from the standard dataset of the LRP problem, and the results show that the solution provided by the improved algorithm outperforms the solutions provided by the standard multi-objective cuckoo search algorithm and the NSGA-II algorithm in terms of the total cost of dissipation, the level of psychological panic of the people in the affected area, the rate of utilization of the supplies, and the number of distribution centers open. Finally, the improved algorithm was used to analyze cases of different sizes separately, and it was found that the algorithm yielded better results and was therefore able to demonstrate its effectiveness.

Child Marriage Issue in Lao Cai Province, Vietnam: Current Situation and Solution

Child Marriage Issue in Lao Cai Province, Vietnam: Current Situation and Solution

An exact solution for unsteady three-dimensional magnetohydrodynamic Casson flow of dusty nanofluid over a porous stretching sheet

The unsteady three-dimensional (3D) Casson flow of a nanofluid containing dust particles over a porous, linearly stretching sheet in the presence of an external magnetic field is studied. It is assumed that the sheet is stretched in both directions along the xy plane. The governing equations of the two-phase model are partial differential equations that are transformed into ordinary equations using similarity transforms. The nanofluid is a suspension of water-based nanoparticles. In this study, we look at how nanoparticle size affect the properties of dusty nanofluid flow. The mathematical model contains the basic equations for the fluid and dust phases in the form of three-dimensional partial differential equations, which are transformed into dimensionless ordinary-dimensional equations using an appropriate similarity transformation. An exact analytical solution to this boundary value problem is obtained. The effects of various physical values on dust and nanofluid velocities are discussed in detail, including the Casson parameter, magnetic parameter, porosity parameter, fluid-particle interaction parameter, mass concentration of dust particles, and nanoparticle size. In a few specific instances, the current analytical solution demonstrates a good agreement with previously published numerical investigations.

Exploring Future Storage Options for ATLAS at the BNL/SDCC facility

Exploring Future Storage Options for ATLAS at the BNL/SDCC facility

On Integrating and Operating Distributed Energy Resources in Distribution Networks: A Review of Current Solution Methods, Challenges, and Opportunities

On Integrating and Operating Distributed Energy Resources in Distribution Networks: A Review of Current Solution Methods, Challenges, and Opportunities

New visual resource-oriented margins for the Resource Constrained Project Scheduling Problem

Scheduling problems are known to be NP-hard. Different optimization methods were employed to solve them. Still, the challenge with this line of problems lies in rescheduling, which turns out to be a time and resource-consuming iterative process where a planner adjusts the current solution until it satisfies the needs. Our paper provides the planner with two new margins computed while considering the overall resource consumption in a schedule. These new indicators showcase which activities are restricted/unrestricted in a schedule under resource constraints. An illustrative example is analyzed to showcase their application in assessing new scheduling options with minor changes.

RESEARCH ON THE SEQUENTIAL QUADRATIC PROGRAMMING DIFFERENTIAL EVOLUTION, JAYA, AND JAYA'S EVOLUTIONARY ALGORITHM

This study focuses on researching and comparing optimization algorithms such as Sequential Quadratic Programming, Differential Evolution, Jaya, and Jaya's evolutionary algorithm. Sequential Quadratic Programming is an optimization method based on mathematical programming, where constraints and objective functions are represented by convex and differentiable functions. Differential Evolution is a combinatorial evolutionary algorithm that utilizes genetic operators such as crossover and mutation to generate new generations of individuals. Jaya is an optimization algorithm based on continuous improvement of the population, where individuals are updated based on the current best solution. This study focuses on the specific application of the Jaya evolutionary algorithm (iJaya) compared to other algorithms and compares the performance of these algorithms in solving optimization problems through real-world examples of fiber orientation optimization in stiffened composite plates. Experiments on popular optimization problems and measure factors such as runtime, accuracy, and the ability to search for optimal solutions were conducted. The research results will provide an overview of the performance and advantages of each algorithm, thereby providing recommendations for selecting the appropriate algorithm for corresponding problems in the construction field.

Secured Service Oriented Communication in V2X Technology

From the day communication started and messages being transmitted and received from one endpoint to another, security was always a concern. And nowadays this is not different from the old ages. In the era of IOT and V2X technology, communication protocols must be safe and secured and the traditional communication approaches like using CAN, LIN and Flexray will be hard to be integrated with IOT systems. Modern approaches are introduced for IOT integration through Ethernet, one of the most used approaches nowadays for vehicle communication is Service Oriented Communication which is represented by several protocols. One of protocols designed by AUTOSAR community is Service Oriented Middleware over Internet Protocol known as SOME/IP. After Surveying Service Oriented Communication, we propose a solution that adds security features to vanilla SOME/IP that prevents possible Denial of Service attacks. In this paper, we will survey the current solution used and tested and compare it with our proposal.

Considerations on the Persons that Can Determine the Manner of the Funeral in the Light of the ECHR Judgment from 23 May 2023 in the Case of Buhuceanu and Others vs. Romania*

Each person owes a death and someone has to take care of the funeral even when the deceased left some instructions. The same happens in the absence of an express option of the deceased. Starting from the current Romanian legislative solution for the latter situation, the present study aims to analyse the impact of the ECHR Judgment from 23 May 2023 in the Case of Buhuceanu and Others v. Romania on the national legal framework that governs the persons who can determine the manner of funeral in the absence of an express option of the deceased. This paper argues the need of legislative intervention in order to secure the same-sex couples’ right to respect for their private and family life by affording them the possibility of legal recognition and protection, including the right to determine the manner of the deceased spouse/partner’s funeral in the absence of an express option of the latter and the right to arrange the funeral, core rights relevant to a couple in a stable and committed relationship.

Development of Electrodeposited Hierarchical Dendritic Wick Structure for Ultra-Thin Vapor Chamber Applications

Compact and light-weight electronic systems have posed stringent dimensional criteria for heat-dissipation components such as heat pipes and vapor chambers. An ultra-thin vapor chamber (UTVC) with an overall thickness below 1 mm requires an interior capillary wick structure less than 100 μm. The capillary wick layer provides a flow path for fluid circulation in an operational UTVC. The maximum UTVC heat transfer rate normally depends on liquid permeability (K) and capillary pressure (∆P) of the wick structure. Large K and ∆P values are rarely realized in typical homogeneous porous structure. In this study, a novel hierarchical dendritic copper wick was prepared to achieve large K and ∆P simultaneously by one-step electrodeposition and thermal sintering process. The effects of electrodeposition parameters, such as current density, deposition time, and solution conditions on the capillary performance of the dendritic copper wicks were investigated. The results indicate that the wicking capability is modulated by the dendritic morphology of Cu deposits. Moreover, a post-deposition sintering process can improve further the structural integrity of the Cu dendrites and the capillary performance of the electrodeposited wicks. An optimal dendritic copper wick of 30 μm in thickness possesses a promising capillary performance K/R eff of 0.811 μm, which is the thinnest wick reported in the literature.

Fluidized bed reactor sizing using manganese aluminium spinel for thermochemical storage

In the field of high-temperature thermal energy storage, the use of reacting systems that reversibly decompose and regenerate, absorbing and releasing heat on demand, is becoming more and more attractive. It is essential in the perspective of achieving high thermal energy density storage, appearing potentially suitable for long-term applications too.Thermochemical Systems (TCS) can contribute to increasing the dispatchability of thermal storage, potentially even on a seasonal timescale. So far, most of this field's scientific works have focused on the conventional concept of fixed-bed reactors. To improve the heat transport phenomena involved in TCS storage, a fluidized bed solution was considered in this article. At this aim, a manganese aluminium spinel, which is a low toxic, low pollutant and very cost-effective is proposed for this application. It was synthesized in the form of properly sized (150–200 μm of diameter) particles to be effectively adopted for fluidizing beds.The present work deals with the sizing of the reactor and its coupling with a Concentrating Solar Thermal (CST) system using the Solar Central Receiver (SCR) technology with air as Heat Transfer Fluid (HTF). Imposing realistic boundaries, an optimal configuration was established, with an operating HTF pressure of 4 bar and a thermal discharging power of about 16 MWth. A volumetric energy density of 170 kWhth/m3 was achieved and, despite a relatively low TES reaction enthalpy, the resulting specific cost of 33 €/kWh demonstrates the suitability of this configuration even for the current thermal storage commercial solution, and shows the high potentiality of this type of storage systems.

A hybrid approach for unit commitment with splitting technique and local search

In the modern electricity market, solving the unit commitment (UC) problem becomes more challenging due to its large number of binary variables and coupling constraints. Therefore, the goal of this paper is to obtain nearly optimal solutions for such complex UC problems within specific time limits. To achieve this, a hybrid approach is presented in this paper, which incorporates a splitting technique and a local search for UC. The hybrid approach involves two steps. In the first step, the augmented Lagrange function (ALF) of UC is decomposed using a splitting technique based on the alternating direction method of multipliers (ADMM). The resulting sub-problems can be effectively solved in a distributed manner by utilizing Lagrange duality theory and binary variable characteristics. Additionally, the penalty parameters of the ALF are updated effectively with the sub-gradient method to diminish the influence of the initial penalty parameters on the algorithm. In the second step, the appropriate relaxation unit is selected using the binary variable characteristics in the current solution of ADMM. Further, the high-quality feasibility of the final solution is ensured through local search. The hybrid approach utilizes ADMM to quickly fix most binary variables in the UC model and then leverages the CPLEX solver to solve the mixed-integer linear programming (MILP) formulation of UC by fixing a large number of binary variables. Consequently, the CPLEX solver needs to branch fewer binary variables, reducing the local search time. The hybrid approach is applied to solve several power systems consisting of up to 1000 units. Compared with the CPLEX solver, the solution of the hybrid approach is found to be stable, and the relative gap of the solution is less than 1 %, demonstrating the effectiveness and performance of the proposed approach while meeting the time limit requirements of the power industry dispatching.