Integral Coefficients Research Articles

Haar wavelet analysis of axisymmetric vibration of 2-D functionally graded porous thin annular plate resting on the Winkler foundation

Purpose In this paper, free axisymmetric vibration analysis of a two-directional functionally graded porous thin annular plate resting on the Winkler foundation is presented utilizing the classical plate theory (CPT). The mechanical properties are considered to be varying in the radial-thickness plane.Design/methodology/approach Based on the CPT, the governing differential equation of motion is derived. The highest-order derivative of displacement is approximated by Haar wavelets and successive lower-order derivatives are obtained by integration. The integration coefficients are calculated using boundary conditions. The fundamental frequency for clamped-clamped, clamped-simply supported, simply supported-clamped and simply supported-simply supported boundary conditions is obtained.Findings The effects of the porosity coefficient, the coefficient of radial variation, the exponent of power law, the foundation parameter, the aspect ratio and boundary conditions are investigated on fundamental frequency. A convergence study is conducted to validate the present analysis. The accuracy and reliability of the Haar wavelets are shown by comparing frequencies with those available in the literature. Three-dimensional mode shapes in the fundamental mode for all four boundary conditions are presented.Originality/value Based on the Haar wavelet method, a free axisymmetric vibration model of a porous thin annular plate is solved in which 2-D variation of mechanical properties is considered.

ON THE PROPERTY OF UNIFORM COMPLETE CONTROLLABILITY FOR A LINEAR SYSTEM WITH LOCAL INTEGRABLE COEFFICIENTS

In this paper, the property of uniform complete controllability for linear systems with locally integrable and integral coefficients is introduced (definition 3). The presence of the studied property in such systems allows solving problems of both local and global control of their asymptotic characteristics, i. e. control of the asymptotics of solutions of these dynamic systems (for more details, see the monograph [3]). The latter fact confirms the relevance of the present research.

The effect of different mission profiles and ambient temperature on the lifetime of boost converter IGBT with a robust controller in a hybrid electric vehicle

AbstractThe reliability of power electronic converters is one of the essential issues in designing of electric vehicles. This paper estimates the lifetime of the boost converter switch by Semikron and Coffin‐Manson models for two common failure mechanisms of Bond wire and Base plate solder, respectively. Four mission profiles based on the Artemis standard are applied to hybrid electrical vehicle model to determine unidirectional output power. Kharitonov's theory is used to design a robust controller to handle the uncertainty raised by different power cycles of the electric vehicle and the parameters of the converter during simulation. Stability of converter is achieved during simulation by identifying simple proportional integral controller coefficients with Kharitonov's theorem. A prototype 230 W boost converter is designed and utilized to validate average model and switch loss calculation relationships. The lifetime results indicate that the number of cycles, and the average and the maximum junction temperature have a more impact than the duration of the drive cycle on the lifetime of the converter. A mixed mission profile is considered to investigate the effect of sudden change in driving modes and speed on total consumed life and lifetime to enhance the study's applicability. Lifetime of switch is decreased significantly in mixed mode in comparison with other mission profiles in the same driving time. Furthermore, the motorway mission profile has 53%, 39.6%, and 160% less total consumed life in comparison with the urban, rural and mixed mission profiles, respectively. In addition, the effect of ambient temperature changes on IGBT lifetime has been investigated for four mission profiles. While motorway had the least total consumed life in 25°C, the urban had better performance in comparison with other mission profiles from 25 to 55°C.

On a class of evolution equations in Lipschitz subdomains of Riemannian manifolds

We study the existence, uniqueness, analyticity, and continuous dependence of mild solutions for a class of evolutionary integrodifferential equations with free boundary conditions on L p -spaces in Lipschitz subdomains of Riemannian manifolds. Our strategy is to use the Laplace transform theory to ensure the existence of an analytic resolvent to the Hodge–Laplacian in the space of all ℓ-differential forms with p-th power integrable coefficients.

Adaptive Virtual Synchronous Generator Control Strategy Based on Frequency Integral Compensation

With the increasing proportion of power electronic equipment in the power system, improving the inertia and damping characteristics of the system through virtual synchronous generator (VSG) control technology has become a hot research topic. In terms of adjusting the output frequency, traditional primary frequency modulation control cannot ensure that the output frequency is maintained within the safe operating range when the load disturbance is large, so secondary frequency modulation with the integral link is usually adopted. However, the fixed integral coefficient cannot solve the contradiction between system regulation time and frequency oscillation. In this paper, a strategy of coordinated adaptive control based on the integral coefficient, moment of inertia, and damping coefficient is proposed. According to the offset of frequency and the change rate of the frequency offset, the value of parameters is determined, and the specific parameter setting method is determined. Finally, the correctness of the proposed control strategy is verified on a simulation platform and a semi-physical experimental platform.

Low temperature dynamics of H + HeH+→ H2+ + He reaction: On the importance of long-range interaction.

While the growing realization of the importance of long-range interactions is being demonstrated in cold and ultracold bimolecular collision experiments, their influence on one of the most critical ion-neutral reactions has been overlooked. Here, we address the non-Langevin abrupt decrease observed earlier in the low-energy integral cross-sections and rate coefficients of the astrochemically important H + HeH+→ H2+ + He reaction. We attribute this to the presence of artificial barriers on existing potential energy surfaces (PESs). By incorporating precise long-range interaction terms, we introduce a new refined barrierless PES for the electronic ground state of HeH2+ reactive system, aligning closely with high-level abinitio electronic energies. Our findings, supported by various classical, quantum, and statistical methods, underscore the significance of long-range terms in accurately modeling reactive PESs. The low-temperature rate coefficient on this new PES shows a substantial enhancement as compared to the previous results and aligns with the Langevin behavior. This enhancement could noticeably affect the prediction of HeH+ abundance in early Universe condition.

Energy Security and Women’s Empowerment: A Generalized Method of Moments Approach from a Global Perspective

The importance of energy security is emphasized in Goal 7 of the 17 Sustainable Development Goals (SDGs) of the 2030 Agenda to guarantee that everyone has affordable, dependable, and contemporary energy access. In addition to transforming human life, whole economies, and even the planet, sustainable energy offers a chance for a better future. The absence of energy security impacts serious health problems, education, and household difficulties. Research on energy security has emphasized various angles worldwide. However, investigations of the impact of energy security on women’s empowerment are still scant. This study thus investigates the relationship between energy security and women’s empowerment (WE) in 167 countries from 2002 to 2021, as well as the influence of urbanization development levels on this nexus. Moreover, this study explores the variation in women’s empowerment between geographical regions by referencing the MENA, OECD, and SAARC countries. A two-step system GMM was used to achieve the objectives of this research. The findings show first that renewable energy availability has a significant effect on WE worldwide. Secondly, in terms of energy security, the variables total availability of natural resource rents and renewable energy both have a positive impact on women’s empowerment in the MENA, while in the OECD and SAARC countries, they have an indirect link with WE. Third, the integrating effect of total natural resource rents with urbanization significantly affects WE in all five models. Fourth, we used access to electricity to represent resource affordability. Unexpectedly, the results show its negative and significant association with WE. Fifth, in terms of energy security, both energy availability and affordability favor WE in OECD countries. Finally, the coefficient of integration of access to electricity and urbanization shows a positive and significant association with WE in the OECD, MENA, and SAARC regions. However, it is noteworthy to mention that access to electricity alone does not influence WE worldwide. Additionally, a series of tests confirm the robustness of the results. This research provides insight into the development and implications of energy security-related women’s empowerment policies.

МЕТОДИ ВИЗНАЧЕННЯ ЕКСПЛУАТАЦІЙНИХ ПОКАЗНИКІВ МАШИН ТРАНСПОРТНОГО БУДІВНИЦТВА

The article presents the main methods of determining the main operational indicators of transport construction machines, which are their fuel efficiency and environmental friendliness. Considered international standards such as STAGE and TIER set emission limits for off-road equipment, including transport construction machinery. In Ukraine, the SOU 42.1-37641918-094:2017 standard is used to determine the fuel efficiency of road machines and mechanisms, which determines the consumption norms of fuel and lubricants. The calculations are based on the specific fuel consumption at the nominal power of the engine and the integral coefficient, which takes into account the average operating conditions of the machine during the work shift. Typical engine load charts were analyzed to study the efficiency and environmental friendliness of special machines used in transport construction and other industries. They reflect the dependence of the torque change on the duty cycle time. Another research method involves testing using the test cycles described in ISO 8178. The procedure involves the use of several test cycles on an engine test bench. These cycles vary depending on the engine class and the type of equipment being tested. Each cycle is a sequence of stable or transient modes of operation of the engine with different load factors. In cases where laboratory testing is not possible or suitable, ISO 8178-2 provides measurements in real operating conditions using a portable emission measurement system (PEMS). This allows you to receive data directly during the normal operation of the car. Test cycles are key tools for evaluating the fuel efficiency and environmental performance of construction vehicles. They allow you to simulate different modes of operation and obtain accurate data on the operational properties of the equipment. However, given the unique characteristics and operating conditions of different types of machines, there is a need to develop specialized test cycles that best match the actual conditions of use of the equipment. Keywords: test cycle, performance indicators, consumption norms of fuel and lubricants, fuel efficiency, environmental safety, toxicity norms, engine load chart, portable system for measuring harmful emissions, transport construction machines.

Abnormal Dynamic Reconfiguration of Multilayer Temporal Networks in Patients with Bipolar Disorder.

Multilayer networks have been used to identify abnormal dynamic reconfiguration in bipolar disorder (BD). However, these studies ignore the differences in information interactions between adjacent layers when constructing multilayer networks, and the analysis of dynamic reconfiguration is not comprehensive enough; Methods: Resting-state functional magnetic resonance imaging data were collected from 46 BD patients and 54 normal controls. A multilayer temporal network was constructed for each subject, and inter-layer coupling of different nodes was considered using network similarity. The promiscuity, recruitment, and integration coefficients were calculated to quantify the different dynamic reconfigurations between the two groups; Results: The global inter-layer coupling, recruitment, and integration coefficients were significantly lower in BD patients. These results were further observed in the attention network and the limbic/paralimbic and subcortical network, reflecting reduced temporal stability, intra- and inter-subnetwork communication abilities in BD patients. The whole-brain promiscuity was increased in BD patients. The same results were observed in the somatosensory/motor and auditory network, reflecting more functional interactions; Conclusions: This study discovered abnormal dynamic interactions of BD from the perspective of dynamic reconfiguration, which can help to understand the pathological mechanisms of BD.

Fekete-Szegö and Hankel inequalities related to the sine function

ABSTRACT The Fekete-Szegö inequality is one of the inequalities for the coefficients which associated with the famous Bieberbach conjecture. Other issues associated with this inequality are determining the Hankel determinant denoted as Hd inequalities which are involved in the study of the singularities and integral coefficients in the Taylor series representations. In this investigation, we discuss such inequalities for certain mappings g for which ( g ′ ( z ) ) α [ 2 z g ′ ( z ) g ( z ) − g ( − z ) ] ( 1 − α ) ≺ 1 + sin ⁡ z , ( 0 ≤ α ≤ 1 ) lies in the image domain starlike about 1 and symmetric about real axis. Particularly, we obtain certain inequality for functions involving Poisson distribution. Furthermore, we also find the second Hankel determinant and other inequalities related to this newly defined class.

УДОСКОНАЛЕННЯ ЗАСОБІВ ЗАБЕЗПЕЧЕННЯ ЯКОСТІ ЕЛЕКТРОЕНЕРГІЇ В СУДНОВИХ ЕЕС З НАПІВПРОВІДНИКОВИМИ ПРОПУЛЬСИВНИМИ КОМПЛЕКСАМИ

Considered are possible directions for improving the means of ensuring the quality of electric power (PQ) in order to increase their efficiency, taking into account the schematic and mode features of integrated ship electric power systems (SEPS) with semiconductor propulsion complexes (SPC). One- and two-link variants of system controlled filter com-pensation devices (CFCD) designed for simultaneous full compensation of reactive power, as well as significant weak-ening of harmonic distortions of voltage and current in SEPS with SPC, are proposed and investigated. A modeling approach has been implemented that allows to compare the effect of the proposed CFCD on the integral coefficient of voltage harmonic distortions in systems with different types of input rectifiers as part of the frequency converters (FC) of the SPC, taking into account the possible deviation of the frequency of the ship's network. Ref. 7, fig.7, table.

Repetitive transcranial magnetic stimulation reshaped the dynamic reconfiguration of the executive and reward networks in individuals with tobacco use disorder

BackgroundStudies have demonstrated the potential of repetitive transcranial magnetic stimulation (rTMS) to decrease smoking cravings in individuals with tobacco use disorder (TUD). However, the neural features underlying the effects of rTMS treatment, especially the dynamic attributes of brain networks associated with the treatment, remain unclear. MethodsUsing dynamic functional connectivity analysis, this study first explored the differences in dynamic functional network features between 60 subjects with TUD and 64 nonsmoking healthy controls (HCs). Then, the left dorsolateral prefrontal cortex (DLPFC) was targeted for a five-day course of rTMS treatment in the 60 subjects with TUD (active rTMS in 42 subjects and sham treatment in 18 subjects). We explored the effect of rTMS on the dynamic network features associated with rTMS by comparing the actively treated group and the sham group. ResultsCompared to nonsmokers, TUD subjects exhibited an increased integration coefficient between the frontoparietal network (FPN) and the basal ganglia network (BGN) and a reduced integration coefficient between the medial frontal network (MFN) and the FPN. Analysis of variance revealed that rTMS treatment reduced the integration coefficient between the FPN and BGN and improved the recruitment coefficient of the FPN. LimitationsThis study involved a limited sample of young male smokers, and the findings may not generalize to older smokers or female smokers with an extensive history of smoking. ConclusionrTMS treatment of the left DLPFC exhibited significant effectiveness in restructuring the neural circuits associated with TUD while significantly mitigating smoking cravings.

Exel–Pardo algebras with a twist

Takeshi Katsura associated a C^{\ast} -algebra C^{\ast}_{A,B} to a pair of square matrices A\ge 0 and B of the same size with integral coefficients and gave sufficient conditions on (A,B) to be simple purely infinite (SPI). We call such a pair a KSPI pair. It follows from a result of Katsura that any separable C^{\ast} -algebra \mathfrak{A} which is a cone of a map \xi:C(S^{1})^{n}\rightarrow C(S^{1})^{n} in Kasparov’s triangulated category KK is KK -isomorphic to C^{\ast}_{A,B} for some KSPI pair (A,B) . In this article, we introduce, for the data of a commutative ring \ell , non-necessarily square matrices A , B and a matrix C of the same size with coefficients in the group \mathcal{U}(\ell) of invertible elements, an \ell -algebra \mathcal{O}_{A,B}^{C} , the twisted Katsura algebra of the triple (A,B,C) . When A and B are square and C is trivial, we recover the Katsura \ell -algebra first considered by Enrique Pardo and Ruy Exel. We show that if \ell is a field of characteristic 0 and (A,B) is KSPI, then \mathcal{O}_{A,B}^{C} is SPI, and that any \ell -algebra which is a cone of a map \xi:\ell[t,t^{-1}]^{n}\rightarrow \ell[t,t^{-1}]^{n} in the triangulated bivariant algebraic K -theory category kk is kk -isomorphic to \mathcal{O}_{A,B}^{C} for some (A,B,C) as above so that (A,B) is KSPI. Katsura \ell -algebras are examples of the Exel–Pardo algebras L(G,E,\phi) associated to a group G acting on a directed graph E and a 1 -cocycle \phi:G\times E^{1}\rightarrow G . Similarly, twisted Katsura algebras are examples of the twisted Exel–Pardo \ell -algebras L(G,E,\phi_{c}) we introduce in the current article; they are associated to data (G,E,\phi) as above twisted by a 1 -cocycle c:G\times E^{1}\rightarrow \mathcal{U}(\ell) . The algebra L(G,E,\phi_{c}) can be variously described by generators and relations, as a quotient of a twisted semigroup algebra, as a twisted Steinberg algebra, as a corner skew Laurent polynomial algebra, and as a universal localization of a tensor algebra. We use each of these guises of L(G,E,\phi_{c}) to study its K -theoretic, regularity, and (purely infinite) simplicity properties. For example, we show that if \ell is a field of characteristic 0 , G and E are countable, and E is regular, then L(G,E,\phi_{c}) is simple whenever the Exel–Pardo C^{\ast} -algebra C^{\ast}(G,E,\phi) is, and is SPI if in addition the Leavitt path algebra L(E) is SPI.

Parameter identification of photovoltaic current loop parameters based on parameter separation

Abstract Accurate control parameters are the basis for analyzing the fault characteristics of PV, but due to technical confidentiality reasons, equipment manufacturers do not provide accurate parameters, so they need to be identified. This paper aims to solve the problem of poor accuracy of the integration coefficient identification of a current loop with low sensitivity by proposing a parameter identification method for a photovoltaic current loop based on parameter separation. By analyzing the current response of the fault and fault recovery stages, the scale coefficient kp and the integration coefficient ki are separated and identified separately. Finally, a simulation system was built on the PSCAD/EMTDC platform, and the validity of the method was verified by using the simulation data.

Submerged rigid vegetation effects on flow hydrodynamics within the pool morphology

AbstractThis research is centered on a comprehensive investigation into the impact of turbulence on the movement and dispersion of materials within a three‐dimensional (3D) bedform, specifically when there is a continuous presence of rigid vegetation submerged in the flow. To achieve our research objectives, we conducted extensive velocity measurements within a channel featuring this submerged vegetation. The measurements were carried out using an Acoustic Doppler Velocimeter (ADV). Additionally, our study delved into the intricate structures and turbulent characteristics of the flow, considering the coexistence of submerged vegetation and a 3D gravel pool. This pool featured entrance and exit slopes measuring 3 and 2.5°, respectively. Our experimental setup took place in a straight flume, measuring 14 m in length, 0.9 m in width, and 0.6 m in depth. The flume was equipped with transparent side walls to facilitate observations. Furthermore, our investigation extended to the spatial variations in velocity and turbulence distributions. We analyzed various parameters including turbulence kinetic energy, integral turbulence lengths, dispersion coefficients, and advective transport. The results revealed that integral length scales offer key insights into turbulent eddy behavior. In the presence of vegetation and a 3D bedform, turbulent eddies undergo notable changes, flattening in the longitudinal direction and expanding in the transverse and vertical directions. Moreover, longitudinal advection is notably higher compared to flows without vegetation in a uniform flow or bare channel, especially for z/H > 0.2. This indicates that the presence of vegetation and a 3D bedform leads to an increase in turbulent kinetic energy (k values) that surpasses the reduction in the time‐averaged velocity component (“U”) in the U × k term, thereby enhancing longitudinal advection.

ANN‐PID based automatic braking control system for small agricultural tractors

AbstractBraking system is a crucial component of tractors as it ensures safe operation and control of the vehicle. The limited space availability in the workspace of a small tractor exposes the operator to undesirable posture and a maximum level of vibration during operation. The primary cause of road accidents, particularly collisions, is attributed to the tractor operator's insufficient capacity to provide the necessary pedal power for engaging the brake pedal. During the process of engaging the brake pedal, the operator adjusts the backrest support to facilitate access to the brake pedal while operating under stressed conditions. In the present study, a linear actuator‐assisted automatic braking system was developed for the small tractors. An integrated artificial neural network proportional–integral–derivative (ANN‐PID) controller‐based algorithm was developed to control the position of the brake pedal based on the input parameters like terrain condition, obstacle distance, and forward speed of the tractor. The tractor was operated at four different speeds (i.e., 10, 15, 20, and 25 km/h) in different terrain conditions (i.e., dry compacted soil, tilled soil, and asphalt road). The performance parameters like sensor digital output (SDO), force applied on the brake pedal (), and deceleration were considered as dependent parameters. The SDO was found to good approximation for sensing the position of the brake pedal during braking. The optimized network topology of the developed multilayer perceptron neural network (MLPNN) was 3‐6‐2 for predicting SDO and deceleration of the tractor with a coefficient of determination () for the training and testing datasets of the SDO and deceleration were obtained as 0.9953 and 0.9854, and 0.9254 and 0.9096, respectively. The Ziegler–Nichols (Z‐N method) method was adopted to determine the initial optimal gains of the PID controller and later these coefficients were optimized using response surface methodology. The optimized proportional (), integral (), and derivative () coefficient values were 4.8, 6.782, and 3.15, respectively. The developed integrated ANN, that is, MLPNN and PID‐based algorithm could successfully control the position of the brake pedal during braking. The stopping distance and slip of the tractor during automatic braking increased with an increase in the forward speed for the tractor from 10 to 25 km/h in all the selected terrain conditions.

UNDERSTANDING THE RELATIONSHIP BETWEEN TASK CONFLICT AND CONSTRUCTION PROJECT PERFORMANCE: UNCERTAINTY MANAGEMENT PERSPECTIVE

Task conflict is prevalent among construction project parties, however, how task conflict affects construction project performance still lacks a comprehensive investigation. Against this background, this study adopts an uncertainty management perspective to conduct an integrative model including both positive and negative mediators as well as one moderator to investigate the link between task conflict and construction project performance. Using 206 samples from the Chinese construction industry, the proposed hypotheses are empirically examined. Results suggest that project commitment (effect size = –0.046) negatively mediates the link between task conflict and project performance, whereas knowledge integration (effect size = 0.053) has a positive mediating effect. What’s more, task reflexivity is found to mitigate the negative effects of task conflict on both project commitment (coefficient of interaction item = 0.12) and knowledge integration (coefficient of interaction item = 0.08). It is also found that task reflexivity changes the direction and strength of the link from task conflict to project performance by both project commitment (from –0.155 to 0.069) and knowledge integration (from –0.049 to 0.052). These findings provide a holistic understanding of the relationship between task conflict and construction project performance, thus contributing to construction project management theoretically and practically.

Quality evaluation of surrounding rocks in a mine shaft based on the game gray target model

Accurate evaluation of surrounding rock quality grade can help guarantee the safety of tunnel design and construction; hence, it has great significance in the construction of mine shafts. Accordingly, the uniaxial saturated compressive strength of the rock block Rc, rock quality index RQD, rock softening coefficient kR, integrity coefficient of the rock mass kv, depth H, unit weight of the rock mass γ, coefficient of quantification of the angle between the principal structural plane and shaft axis k2, and weight of the groundwater k1 are first selected as the indexes of assessment to introduce the game gray target model. Then, the gray target model of the surrounding rocks in a mine shaft project is established. The weight coefficient of each index is next calculated using the combination weighting method based on game theory, and the synthetic target center distance of each sample is determined using the gray target model. Finally, the quality level of the asphalt pavement is determined. The suggested model can be used to mine a small data sample to the maximum extent possible, thereby minimizing the information shortage caused by the small sample to a certain extent, to evaluate the final quality grade of the surrounding rocks quantitatively. Thus, the proposed approach provides a new scheme for the future quality assessments of surrounding rocks.

Classification of pairing phase transition in metal clusters in vanadium and aluminum particles using Grossman theory

In this work, the phase transition from normal to superconductivity state of two metal clusters, vanadium and aluminum particles, are theoretically studied by changing size and resistance parameter. We obtained the heat capacity integral of Grossman's theory considering that the first zero of the partition functions is located in the complex temperature plane. Then, we used the experimental data of the heat capacity of aluminum metal clusters and vanadium particles to determine the unknown integral coefficients of the heat capacity of Grossman's theory. Based on the obtained coefficients, we discussed the classification of the phase transition of the aforementioned metal clusters. Also, the obtained coefficients have been used to plot the heat capacity of aluminum metal clusters and vanadium particles. Finally, we compared the obtained heat capacity with the experimental results. A good agreement between our results and the experimental data has been obtained.

Non-Homogeneous Binary Cubic Equation a(x-y)<sup>3</sup>=8bxy

Polynomial equations an interesting subject in theory of numbers, occupy a pivotal role in the realm of mathematics and have a wealth of historical significance. The theoretical importance of polynomial equations of third degree in two unknowns having integral coefficients is great as they are closely connected with many problems of number theory. Specifically, the third degree polynomial equations having two unknowns in connection with elliptic curves occupy a pivotal role in the region of mathematics. This paper discusses on finding many solutions in integers to a typical third degree equation having two variables expressed as a(x-y)<sup>3</sup>=8bxy. The substitution strategy is employed in obtaining successfully different choices of solutions in integers. Some of the special fascinating numbers, namely, Pyramidal numbers, Polygonal numbers, Centered pyramidal numbers, Centered polygonal numbers, Thabit ibn Qurra numbers, Star numbers, Mersenne numbers and Nasty numbers (numbers expressed as product of two numbers in two different ways such that the sum of the factors in one set equals to the difference of factors in another set) are discussed in properties. These special numbers are unique. and have attractive characterization that set them apart from other numbers. The process of formulating second order Ramanujan numbers with base numbers as real integers is illustrated through examples.