Energy Method Research Articles

A new damage identification approach of HFSGCW based on LDV and wavelet packet band energy method

This study introduces a damage assessment system and a pivotal detection technique for hidden frame-supported glass curtain wall (HFSGCW) structural sealant. The vibration performance of HFSGCW is evaluated using a laser Doppler vibrometer (LDV). The acquired signals undergo wavelet packet transformation for decomposition. The damage conditions of the structural sealant are analyzed by calculating the sum of squared differences (SSD) of the wavelet packet bands' energy. This SSD indicator serves as the damage indicator. The study investigates the effect of structural sealant damage on the HFSGCW's SSD indicator. Meanwhile, the LDV test results are corroborated with those from numerical simulation analysis to evaluate LDV's viability for detecting the SSD indicator in HFSGCW. The results indicated a strong correlation between the SSD indicator and the numerical modeling analysis. When the structural sealant was damaged, the SSD indicator showed sudden fluctuations, coupled with specific positional indications corresponding to the degree of damage, the type of damage (penetration or non-penetration), and the damage location. This indicator provides a basis for evaluating structural integrity. The research's effectiveness in guiding the construction and assessment of facades is demonstrated by its practical application in the project context.

A novel coupled algorithm for Studying the performance characteristics of water ramjet in the flight of supercavitating vehicle

When a supercavitating vehicle performs a flight, the water ramjet of the vehicle exploits the water in the surrounding environment as an oxidiser and is inevitably affected by the vehicle motions. In this study, the characteristics of the performance change in a water ramjet were investigated when a supercavitating vehicle performs a flight to gain more insights into the design of underwater power systems. Given the principle of independent cross-section expansion of cavities, a longitudinal ventilated supercavity model was built to predict the development of a ventilated cavity and its interaction with the body. A thermal calculation model was developed based on the minimum free energy method to calculate the performance parameters of water ramjets. A novel coupling algorithm was proposed based on the aforementioned model to integrate the motion of a supercavitating vehicle with the operation of a water ramjet. The integration described above was achieved by linking the water intake and body motion and calculating the performance change characteristics of the water ramjet during the flight of the supercavitating vehicle. The operating characteristics of the water ramjet with changes in the designed water-fuel ratios were investigated to provide a basis for exploring the unperturbed flight of the vehicle, depth regulation, and underwater environmental changes. The thrust of the water ramjet is less affected by external factors, and its performance feedback tends to exacerbate external disturbances at a designed water-fuel ratio lower than the optimal water-fuel ratio. A water ramjet with a designed water-fuel ratio higher than the optimal water-fuel ratio has a rapid response time, adaptive thrust, and stable combustion chamber pressure. External disturbances slightly affected the thrust and combustion chamber pressure of the water ramjet when the designed water-fuel ratio was equal to the optimal water-fuel ratio. The results of this study provide technical support for optimising the design of water ramjet.

Global existence and exponential decay for a swelling porous-heat system subject to a distributed delay

In this article, we consider a swelling porous-heat system with viscous damping and distributed delay term. It’s well-known in the literature that the thermal effect only lacks exponential stability. For that, we need to add another damping mechanism to stabilize exponentially the system. However, we prove, based on the energy method, that the combination of viscous damping and thermal effect provokes an exponential stability in the presence of distributed delay irrespective of the wave speeds of the system.

The asymmetric effect of monetary policy on core inflation in Jordan: NARDL model

This study aimed to estimate the asymmetric impact of monetary policy on core inflation rates in Jordan during the period 2000-2020 using the Nonlinear Autoregressive Distributed Lag Model (NARDL) Based on quarterly data. The unit root tests showed the different degrees of integration by applying the Augmented Dickey-Fuller Test (ADF) and Philip Perron (P.P). and has a cointegration relationship using Johansson's test, and the Bound test. Also, there is a nonlinear relationship in the time series using waled test. The study used Core Inflation (CORINF) as a dependent variable (calculated based on excluding energy and food prices method) and the overnight deposit rate (CBJR), the loan and advances interest rate (LR), the growth in money supply (GM2), and the growth in real GDP (GRGDP) used as independent variables. The results indicated that there are asymmetric effects of both CBJR and GM2 on core inflation, as a 1% increase in GM2 leads to an increase in the CORINF by 1.3%, while its decrease by 1% leads to a decrease in the CORINF by 1.2%, in contrast, an increase in the LR by 1% leads to a decrease in the CORINF by 0.15% and a decrease by 1% leads to a rise in the CORINF by 0.44%, and the study also found that a rise in LR by 1% lead to a decrease in the CORINF by 0.43%, while its decrease by 1% leads to a rise in the CORINF by 0.44%.

SIMULATION OF RELIABILITY, RELIABILITY INDEX, PROBABILITY DENSITY FUNCTION AND FAILURE FUNCTIONS FROM WEIBULL DISTRIBUTION FOR ENGINEERING APPLICATIONS

In modelling and simulating future rainfall for a selected location, the probability distributions have been established to be an effective tool. In this study, the different methods utilised in the estimation of the probability distributions’ parameters were evaluated and presented using Weibull's two parameters. Different estimator methods (mean rank, median rank, symmetric, graphical, least square, empirical, maximum likelihood, general probability, modified maximum likelihood, Mabchour, alternative maximum likelihood, equivalent energy, moment expression, Lysen and Moment methods) were used to determine probability density function, reliability, reliability index and failure functions of rainfall data from Maiduguri. The performances of these different methods were compared probability density function, reliability, reliability index and failure functions of Weibull two parameters. The study revealed that the values of probability distribution dimensionless shape variables were between 1.0193 and 4.205, and probability distribution scale factor constants were between 0.302 and 7.254. These values are all positive (non-negative values or less than zero) values. It was established that there were significant differences (F108, 1728 was 162.1976 and the probability (p) was zero) between the individual reliabilities and Weibull estimators (F15, 1620 was 14928.98 and probability was zero) at a 95 % confidence level (p less than 0.05). It was concluded that caution must be taken in the utilization of general probability, equivalent energy, Alternative Maximum Likelihood Method and moment expression methods in any engineering applications to prevent failure of devices or infrastructure.

Stability of a fractional heat equation with memory

Of concern is a fractional differential problem of order between zero and one. The model generalizes an existing well-known problem in heat conduction theory with memory. First, we justify the replacement of the first order derivative by a fractional one. Then, we establish a Mittag-Leffler stability result for a class of heat flux relaxation functions. We will combine the energy method with some properties from fractional calculus.

INTEGRATION OF HYBRID ENERGY PLANT OPERATION

Integrated use means the use of several energy sources, all at the same time or in some combination. At the same time, it is possible to use exclusively renewable sources, which significantly limits user capabilities. More common and justified from many points of view is the use of both renewable and traditional sources, autonomous (universal boilers, diesel generators, gas turbine units, etc.) or centralized (power grid) sources. A correct assessment of such a combined energy system also requires taking into account the main component of the system - the consumer, that is, taking into account the features of the local network and nearby consumers, which will have a direct or tangible indirect effect on the operating mode of the complex of renewable sources. To ensure adequate power quality, energy storage systems can be used, and the need for them depends on the discreteness of energy flows and the requirements for power quality. In foreign terminology, combined systems are often called hybrid, reflecting the diversity of both energy sources and methods of combining them (sometimes this name extends to arbitrary complexes). However, the term “hybrid power supply” usually refers to a combination of installations using renewable and traditional energy sources. The article presents a new hybrid energy system that provides private households with electricity, hot water supply, heating and hot air in the required temperature range for comfortable living. Together with a wind power generator and an electric water heater, a heat pump, electricity and heat accumulators are used, which allows: - reducing the cost of thermal energy by reducing material consumption and equipment costs, saving organic fuel; produce electricity and send the excess to the state power grid; reduce heat load and environmental pollution. The automation system allows you to control the hybrid installation without human intervention all year round.

Improving energy consumption with ADAS in autonomous driving communication system

The article analyses the trends in the development of energy saving and recovery technologies in electric motor vehicles. Promising directions for the development of energy saving technologies, in particular with the use of driver assistance systems, are considered and identified. Increasing the occupancy of cars with electronic driver assistance systems increases the overall energy consumption. Recommendations for choosing the optimal technologies and methods of energy saving for motor vehicles are given. For some methods, saving energy is a complement to the main area of work. The combination of intelligent vehicles and appropriate traffic management tools can help to further realise the transport benefits of intelligent vehicles.

A complete orthogonal decomposition method for the comprehensive deformation energy of discrete elastomers

A complete orthogonal decomposition method for the comprehensive deformation energy of discrete elastomers

Evaluation of energy performance and environmental benefits for transcritical CO2 thermal system in high-speed trains

The conventional air conditioning system used in high-speed railways has limitations in heating performance and environmental impact, necessitating the exploration of alternative refrigerants. The transcritical CO2 system has gained popularity due to its exceptional heating efficiency and environmental benefits. This study aims to evaluate the energy and environmental potentials for transcritical CO2 systems in high-speed trains based on four-vertical-and-four-horizontal railway lines within different climatic regions of China. A high-fidelity transcritical CO2 system model was first developed and validated through experiments. Then, a comprehensive energy and environmental evaluation method was proposed and applied to the four-vertical-and-four-horizontal railway lines. The results indicated that the transcritical CO2 system had a superior heating performance and competitive cooling performance based on daily and annual operations. Furthermore, the transcritical CO2 system exhibited significant environmental advantages with lower total life cycle climate performance for all lines, with an average emissions reduction ratio of 17.6% and a maximum emissions reduction ratio of 26.98%. These findings highlight the competitive energy performance and outstanding environmental benefits offered by transcritical CO2 systems as promising alternatives to air conditioning systems in railway transportation.

Variability of strength and stiffness assessment for non-profile beam structures

Introduction. Traditional ways to increase the structural strength and stiffness of beams are now almost exhausted, and optimization of production and operation technologies is mostly based on the use of new materials and increasing their reliability as bearing elements of a complex geometric profile. Bearing elements of building structures operate under high loads and, even despite their predominantly static nature, experience a complex volumetric stress and strain state, which can scarcely ever be confirmed empirically and statistically.Aim. To propose an approach to assessing the strength and stiffness of beam structures operating under conditions of transverse bending of a complex geometric profile.Materials and methods. Classical energy methods, including Castigliano, Maxwell–Mohr and Vereshchagin methods (moment area method), have been used to assess the strength and stiffness of non-profile beam structures, initial parameters, differential equations of the deflection curve.Results. The similarity parameters (fitting criteria) of Mises–Hencky and Zhurkov reflect the behavior of a brittle or plastic beam material reasonably well. These characteristics are proposed to be combined in the Arrhenius–Zhurkov durability functions.Conclusions. The dependencies given in the calculations can be recommended for improving the flexural static and fatigue strength, as well as the stiffness of the bearing elements of building structures.

Nonlinear Buckling and Postbuckling Response of Porous FGM Shallow Spherical Caps and Circular Plates with Nonlinear Elastic Foundation Effects Using the Ritz Energy Method

Nonlinear Buckling and Postbuckling Response of Porous FGM Shallow Spherical Caps and Circular Plates with Nonlinear Elastic Foundation Effects Using the Ritz Energy Method

Geometrically nonlinear bending analysis of laminated thin plates based on classical laminated plate theory and deep energy method

This paper establishes a geometrically nonlinear bending analysis framework using the deep energy method and the classical laminated plate theory (CLPT) for laminated plates. Inspired by the transfer learning technique, a load applied to a laminated plate can be divided into multiple load steps. The network parameters for the current load step, with the exception of the initial step, are initialized by inheriting values from their preceding steps. Including both von Kármán and Green-Lagrange strains, the plate strains are computed using the automatic differentiation and integrated along the thickness direction per laminate plate based on the constitutive theory. By combining the outputs of neural network, the external potential energy can be obtained, and the optimized network parameters are given by minimizing the total system potential energy of the laminated plate. In order to validate the proposed approach, several numerical examples are calculated, and the present solutions are compared with those given by the literature and the Finite Element Analysis (FEA). The results show that the proposed approach is indeed feasible, can reach high levels of precision under varying loads while offering a simplified calculation strategy.

Vibration and aeroelastic instability analysis in GPL-porous multi-layered beam with the rotation effect

This research studies the vibrations and instability of a rotating three-layer beam under aerodynamic forces consisting of two functionally graded (FG) composite surfaces and a porous intermediate layer. Linear poroelasticity theory is used for modeling the porous layer while Young’s modulus and density vary along the thickness. Equivalent coefficients of the graphene nanoplatelets-reinforced composite (GPLs) are extracted by modified Halpin-Tsai theory, according to five different configurations. The equations of motion in the GPL-porous multi-layered beam are derived using the Euler–Bernoulli beam (EBB), Timoshenko beam (TB), and Reddy’s higher-order shear deformation theory (HSDT) theories, as well as the energy method and Hamilton’s principle. The most important results show the effect of reinforcements and their different configurations, porosity and its distribution, speed of rotation on natural frequency, critical flutter point, and loss factor for a GPL-porous multi-layered beam. The unique properties of GPL-reinforced porous materials facilitate the design of components capable of effectively managing dynamic loads and resisting aeroelastic instabilities. This results in more efficient, reliable, and durable systems across various industries.

Quantitative Assessment of Bed-Separation Dynamic Development Caused by Inclined Coal Seam Longwall Mining

Coal mining under the Quaternary thick loose layer affects key strata breakage, Bed-separations development, ground subsidence, and other studies. This paper presents a method for solving the deflection of a large-deflection inclined thin plate under a thick loose-layer cover with additional lateral loads and midplane forces. The methods presented are based on the principle of large-deflection of thin-plate, energy method, and fracture mechanics theory. The 7225 work face in Anhui Province, China, was studied. Combined with the large-deflection inclined thin plate model, the initial breakage distance within the main roof plate was calculated to be 33 m with the initial breakage angle of 61.2°, and the period breakage distance was calculated to be 21 m with the period breakage angle of 55.4°. The distribution range of “Vertical Three Zones” from 7225 working face to the ground, including the height of the caved zone is 38.07 m, the height of the fractured zone is 41.13 m, and the height of the curved zone with the thick loose layer removed is 187.56 m. During the dynamic development of the principal key strata (PKS), the deflection value develops from 0 mm to 2714 mm with 7225 working face mining, and the maximum value of the spatial volume is 56,485 m3, which is verified by Three-dimensional Discrete Element Code (3DEC) numerical simulation. The dynamic development of Bed-separation within the overlying strata, with a maximum development height of 545.2 mm and a maximum volume of 11,228.1 m3 of the Bed-separation cavity. The dynamic development of the Bed-separation height and the cavity under different mining length and width conditions of the working face are also discussed. The large-deflection inclined thin plate model proposed in this paper effectively explores the dynamic deflection and fragmentation law of the overlying strata induced by the inclined working face of Longwall mining and provides a theoretical basis and computational model for quantitatively evaluating the dynamic development of the Bed-separation cavity.

Solar district heating system with large heat storage: Energy, exergy, economic and environmental (4E) analysis

In the context of the global energy crisis and climate change, solar district heating systems are an essential technology that can mitigate this problem. To accelerate the transition to sustainability, a proven solar district heating system and an analysis method are needed to serve as a role model. For this purpose, a techno-economic analysis method is proposed in this study. It consists of a bi-directional long short-term memory method for correcting outlier data and a balanced method for energy and exergy analyses. The solar district heating system with large-scale thermal storage in Dronninglund, Denmark, is investigated in detail. The design of this system is centered on an integrated control strategy that synchronizes the solar collector loop, the energy storage loop, and the heating load loop to improve overall efficiency. The results show an increase in solar collector efficiency to 41 %, thermal storage efficiency to 89 %, and a coefficient of performance to 1.74 for the absorption heat pump. This integration increases the system’s coefficient of performance dramatically to 2.9, with a renewable energy percentage of 77 %. Exergy analysis shows a storage exergy of 68 % and a heat pump exergy of 49 %, which suggests that the system has a highly efficient energy conversion. The annual heating demand for the industrial and residential branches is 7,450 MWh and 28,100 MWh, respectively, which are covered by solar (42 %), biomass oil (35 %), and natural gas (23 %). The economic assessment shows that the net present value could rise from −5.5 million euros over 10 years to 15.2 million euros over 40 years, indicating long-term economic advantages. The system achieves 122 kg/MWh of carbon reduction with a 0.92 carbon neutrality factor, which is carbon neutral. This study provides a compelling case for deploying large-scale solar heating systems, offering a robust analysis method and insightful findings for technological developments and economic optimizations.

Exploration and Application Practice of Energy Conservation Theory and Method in Steel Manufacturing Process System

This article briefly discusses the theoretical basis and overall goals of energy conservation in the steel manufacturing process system. It is proposed that in the process of implementing system energy conservation, it is necessary to fully recognize and utilize the characteristics and functional advantages of the steel manufacturing process, pay more attention to energy quality, firmly grasp the overall goal of system optimization, focus on the integrated optimization of gas, steam, and waste heat systems, and propose the idea of constructing a "steel chemical gas electricity heating cooling multi generation system". Based on practice, the main principles, models, and effects of implementing systematic energy conservation in steel enterprises have been proposed.

Interactions of a Novel Anthracycline with Oligonucleotide DNA and Cyclodextrins in an Aqueous Environment.

Berubicin, a chemotherapy medication belonging to the class of anthracyclines, is simulated in double-stranded DNA sequences and cyclodextrins in an aqueous environment via full-atom molecular dynamics simulations on the time scale of microseconds. The drug is studied in both the neutral and protonated states so as to better comprehend the role of its charge in the formed complexes. The noncovalent berubicin-DNA and berubicin-cyclodextrin complexes are investigated in detail, paying special attention to their thermodynamic description by employing the double decoupling method, the solvent balance method, the weighted solvent accessible surface model, and the linear interaction energy method. A novel approach for extracting the desolvation thermodynamics of the binding process is also presented. Both the binding and desolvation Gibbs energies are decomposed into entropic and enthalpic contributions so as to elucidate the nature of complexation and its driving forces. Selected structural and geometrical properties of all the complexes, which are all stable, are analyzed. Both cyclodextrins under consideration are widely utilized for drug delivery purposes, and a comparative investigation between their bound states with berubicin is carried out.

An investigation into the effects of profile shifts on helical gear mesh stiffness

Time-varying meshing stiffness (TVMS) is a significant nonlinear periodic excitation in helical gears, it poses significant impacts on gear system’s dynamic characteristics and fatigue life. However, the specific impact of profile shift on it remains unclear. This article establishes an analytical model for the TVMS of helical gears by utilizing the slicing method to address this gap based on the potential energy method, and quantitatively analyze the TVMS with different modification coefficients. The research found that the helical gear’s TVMS decreases with the increase of modification coefficient for individual profile shifts. For the equal compound profile shifts, it rises with the increase of modification coefficient of pinion. For the unequal compound profile shifts, the positive drive increases the TVMS, but the negative drive to the contrary. The research achievements provide valuable guidelines for dynamic design and structure optimization for helical gears.

Torsion modulus to hollow glass microsphere additives in unsaturated polyester resin: Dynamic and deformation energy methods

This paper presents two methods for deformation energy or dynamic for measuring and calculating the torsion modulus, G, for composites with hollow glass microsphere (HGM) additives in unsaturated polyester resin. First, we constructed a measurement system with a torsion pendulum, a force sensor (FS), and a rotational movement sensor (RMS). Then, we deduced a relationship between force (F) and torsion angle (θ) to obtain G by deformation energy. Second, using the relaxation curve, θ in function time (t), we deduce an equation that could return the value of G for dynamic. Both techniques are non-destructive and independent of knowing the value of Poisson’s ratio. We used samples of approximately 5.00 mm diameters, and the influence percentage of HGM additives differed from that of 100%Wt resin. They obtained G values by opting for these composite materials’ different methods, showing a maximum deviation of 5.44%.