Levels Of Energy Input Research Articles

An investigation of the surface topography of wire tool and the modelling of wire electro-spark machined Ti-alloy using ANN

Abstract Titanium and its alloys are in demand in the field of biomedical and aerospace engineering because of its high strength-to-weight ratio and anti-corrosive properties. WESM emerged as a processing method as traditional methods could not process because of strain hardening and low material conductivity; however, wire tool consumption contributes to high costs while processing with WESM. The current Article investigates the effect of input factors on wire consumption and their significance level on wire consumption. 81 experimental runs were conducted while taking input factors Spark on, Spark off time, peak current and servo voltage at three levels, each using a full factorial approach. Experimental results were analysed using ANOVA and MLR (Multi-Linear regression). Moreover, ANN modelling is done to model the wire consumption using a 4-10-1 architecture that increased the coefficient of correlation (R2) up to 0.991. Lastly, after processing, the wire tool surface is evaluated using a scanning electron microscope to assess the effect of various input energy levels and find input combinations for minimum wire consumption.

An inerter-enhanced bistable nonlinear energy sink for seismic response control of building structures

Structural control strategies have attracted great attention in reducing unwanted structural responses. To mitigate the vibrations of seismically excited buildings, this paper proposes a novel vibration control device: an inerter-enhanced bistable nonlinear energy sink (BNESI). A three-story building structure is selected as an example, where the BNESI is attached to the top of the structure and linked to the top second floor of the structure, to explore the control effect of the device under earthquakes. The restoring force of the BNESI and equations of motion for the BNESI-controlled system are derived first. Subsequently, a multi-objective optimization design method of the BNESI is proposed and applied in building structures. The input energy robustness of the BNESI is then accessed by various initial velocities subjected to the structures. Moreover, the seismic vibration mitigation capacity of the BNESI is systematically investigated under a group of near-field and far-field excitations. Analysis results show that the proposed design algorithm for BNESI can be an attractive alternative to effectively obtain optimal parameters of the control device. The BNESI is less sensitive to the input energy levels, and can stably capture and dissipate energy from the primary structure. Also, the BNESI system provides good control effectiveness with less sensitivity to the uncertainty of seismic excitations. In addition, with less standard deviation, the damper stroke of the BNESI is only about a quarter of that of the TMD under the same excitation. Moreover, the damage to the primary structure has a negligible effect on the control effect of the BNESI system. Meanwhile, the BNESI can decrease the energy dissipation demand on the structure, and the energy distribution mode of the BNESI system shows less sensitivity to the frequency decrease of the structure.

Renewable energy input strategy considering different electricity price regulation policies

This paper examines the impact of the electricity price cap regulation and different policies on renewable energy inputs, electricity prices, demands, and the profits of power firm. Specifically, we compare the impact of the peak-trough electricity price policy (PP policy) and the uniform electricity price policy (UP policy) based on electricity price cap regulation. The findings are as follows: (1) Regardless of the cap, the UP policy consistently results in no lower renewable energy input level and total electricity demand compared to the PP policy. However, power firm earns higher profit in the PP policy. (2) During peak period, the electricity price in the PP policy is not lower than in the UP policy, but the electricity demand is lower. Conversely, during the trough period, the electricity price in the PP policy is lower, and the electricity demand is higher than in the UP policy. (3) When the firm is subject to the electricity price cap regulation, increasing the cap leads to higher electricity prices, renewable energy input levels, total demands, and firm profits. In the absence of the cap regulation, factors of cross-price competition and renewable energy preference increase all equilibrium solutions, while the renewable energy input cost factor has the opposite effect. In the field of renewable energy input, there is no literature considering the impact of the electricity price cap regulation, while our study considers the input behavior of power firm to renewable energy through electricity price cap regulation and different pricing policies. The findings provide substantial theoretical and practical insights for power firm and government in decision-making processes.

Optimizing High Data Rate Up to 2.5 Tbps Transmission using 64-Channel DWDM System with DCF and NRZ Modulation

Objectives: This study aims to enhance and optimize a modern communication system for high data rate transmission using Dense Wavelength Division Multiplexing (DWDM). The objectives include employing a 64-channel DWDM system, implementing different data speeds, and utilizing a dispersion compensation method. Methods: To achieve the objectives, we simulate and analyze the effects of Dispersion Compensation Fiber (DCF) in a DWDM system with 64 channels. The system employs Non-Return-to-Zero (NRZ) modulation format at varied bit rates and multiple energy levels. We propose a method for achieving data rates of 10 to 40 Gbps using NRZ modulation and Erbium-Doped Fiber Amplifier (EDFA) over a single-mode fiber transmission distance of 40 to 160 km, along with a dispersion compensation fiber of 8 to 32 km (DCF). The performance of the developed model is evaluated based on Quality Factor, Bit Error Rate (BER), Eye Height, and Threshold. These metrics are measured at two input energy levels from an optical power source, covering a communication capacity ranging from 0.625 Tbps to 2.5 Tbps. Findings: Through the simulations and analyses, we uncover the impact of dispersion and demonstrate the effectiveness of the proposed method in compensating for dispersion effects. Performance analysis of two different input transmitter power levels, -10 dBm is more efficient compared to 0 dBm input transmitter power in terms of bit error rate and quality factor. Novelty: This study presents a novel approach to improving modern communication systems by utilizing DWDM with a dispersion compensation method. The use of a 64-channel DWDM system, combined with the proposed NRZ modulation technique and dispersion compensation fiber, provides an efficient solution for achieving high data rates over long transmission distances while minimizing the effects of dispersion. The findings contribute to the advancement of communication systems for high data rate transmission. Keywords Dispersion effect, Bit Error Rate, Q-factor, Optisystem software, Erbium doped fiber amplifier

A novel design strategy of track‐based asymmetric nonlinear energy sink for seismic response mitigation of structures

AbstractMass dampers, whether linear or nonlinear, rely on resonance with the structure to achieve optimal control performance. However, linear mass dampers require frequency tuning, while nonlinear mass dampers are sensitive to input energy levels, rendering both inadequate for control problems that involve frequency and energy uncertainties. To address this issue, the track asymmetric nonlinear energy sink (TANES) has been developed as a robust mass damper against frequency and energy changes. In this study, a novel design strategy consisting of physical and parameter design was proposed for TANESs. First, TANESs with inverted tracks as the auxiliary mass were proposed, resulting in a significant reduction in the dimensions and weight of the device. The new physical design was then realized, and the mathematical descriptions of the TANES system were validated through experiments on a two‐story frame structure. Subsequently, a parameter design method was proposed to match the frequency variation pattern of the TANES with the given structural and load conditions. Following the design procedure, three TANESs with markedly different track shapes were obtained and compared with existing mass dampers under different types of excitations. Results showed that the frequency responses of the TANES systems subjected to harmonic ground excitations shared great similarity with those of a well‐tuned TMD system at small‐to‐moderate energy levels. As the energy level increased, nonlinear responses such as strongly modulated responses were observed in the TANES systems with decrease structural frequencies, which significantly reduced the resonant peak in the frequency responses. The frequency responses of the TANES systems were consistent with the design objective and could be used to quantitatively predict the robustness performance of the devices under impulsive and seismic excitations. With the reduced dimensions and weight resulting from the inverted‐track configuration and the robustness performance in line with common structural and load conditions, the proposed design strategy of TANESs demonstrated great potential in the seismic response mitigation of engineering structures.

In-situ acoustic signals correlation of process parameters in laser powder bed fusion

Laser Powder Bed Fusion (LPBF) is a metal additive manufacturing technique in which repeatability is considered as a major concern in quality results. Acoustic sensing is one of the methods that can be used to detect the variabilities in the process conditions. In this study, an optical microphone is used to monitor the LPBF process. Inconel 718 powder is processed with different input energy levels for the experimental work. Analyses show a strong correlation between the acoustic signals and the process parameters. Certain process flaws can be assessed and the overall quality can be evaluated using the proposed methodology.

A new probabilistic long-period critical excitation procedure for isolated building structures

The present paper develops a new procedure for finding the most unfavorable long-period excitation for isolated building structures based on the probabilistic critical excitation method. The upper bound of earthquake input energy per unit mass is considered the problem’s constraint, and a modified power spectral density (PSD) function is proposed to conform to the new constraint. It is shown that the new constraint can be used as a criterion to estimate the possible range of input energy of similar earthquakes. In addition, the new PSD function can control the excitation’s intensity. Finally, three base-isolated shear buildings modeled as multi degree of freedom systems with nonproportional damping are considered, and the critical excitations for each model are found based on the proposed method. To examine the reliability of the results, three actual accelerograms with a considerably high level of total input energy are selected as benchmarks and linear dynamic analyses are conducted using these accelerograms along with the generated critical excitations. The results show that the generated long-period excitations can better estimate the structural behavior (i.e., maximum displacement, drift, and absolute acceleration of stories) than the actual benchmark accelerograms.

Experimental study on asymmetric and bistable nonlinear energy sinks enabled by side tracks

To enhance the robustness of nonlinear energy sinks (NESs) against changes in input energy levels, various modifications to the restoring forces have been proposed. However, these improved devices may fail to achieve the expected effectiveness due to ineffective physical implementations. In this short communication, a novel realization method utilizing side tracks is employed to address this issue. Firstly, the development and mathematical descriptions of side-tracked NESs (ST-NESs) are presented. Subsequently, two energy-robust ST-NESs featuring asymmetric and bistable restoring forces are assembled and designed on a physical two-story frame structure subjected to impulsive excitation. Finally, the experimental responses of the two models are analyzed, and the comparison between the experiment and simulation is discussed. The results demonstrate that the proposed ST-NESs can be readily realized with limited vertical dimensions for practical applications. Besides, the device parameters that ensure good control capacities are not unique, providing flexibility in selecting different combinations of track shapes and springs. The experiment show that the two tested devices can reduce the structural response by 50% within five cycles and are minimally affected by changes in excitation levels. However, it is also found in the experiment that large friction among the interfaces of the assemblies in ST-NESs can cause immobility of the auxiliary mass, which should be avoided in future experiments and potential engineering applications.

Effects of input energy and impactor shape on cranial fracture patterns

This study documents relationships between input energy, impactor shape, and the formation of fractures in human crania. Parietal impact experiments (n = 12) were performed at 67% higher input energy compared to previously reported experiments. Fracture origins, characteristics, and locations were compared at two input energy levels with three impactor shapes (focal “hammer”, flat “brick”, and curved “bat”). Impacts with all three impactors at both energy levels produced fractures originating at and remote to the impact site, indicating both mechanisms are typical in temporoparietal blunt force impacts. Higher energy impacts generally produced more impact site fractures, depression, and comminution than lower energy impacts. A small, focal impactor produced cone cracks, depression, and fractures localized near the impact site. A broad, curved impactor produced circumferential fractures and linear fractures extending into adjacent bones. A broad, flat impactor produced fracture patterns ranging from linear fractures to large depressed and comminuted defects.

Development and robustness investigation of track-based asymmetric nonlinear energy sink for impulsive response mitigation

Nonlinear energy sinks (NESs) are known for their capacity of resonating with a wide range of frequencies. However, the occurrence of resonance in NESs strongly depends on the input energy level. To further enhance energy as well as frequency-related robustness and tailor the robust performance to the need of engineering structures, track asymmetric nonlinear energy sinks (TANESs) are proposed in this study. Integrating the merits of two existing mass dampers, TANESs are able to broaden the energy range for effective response mitigation toward both the upper and lower limits. First, the theoretical model of TANESs is developed and validated through experiments on a two-story frame structure. The validated model is then applied to analytically derive the fundamental dynamics of the standalone TANES under impulsive and harmonic excitation. Subsequently, the robust performance of the TANES predicted by the analytical results is numerically investigated when the structure, considering natural frequency variations, is subjected to impulsive excitation of different amplitudes. Finally, the control characteristics and applicable situations of the TANES and other comparable mass dampers are discussed. The results show that the TANES can act as a well-tuned linear mass damper when the input energy is below a certain level and perform more effectively on frequency-decreased structure as the energy level further increases. As decrease in structural frequency is often caused by damages under stronger excitation, TANESs are considered to be a suitable control strategy for engineering structures in practice.

Synchronously Enhanced strength-ductility of L-DEDed GH4169 with Varying Energy Input

The energy input highly determines the microstructure, texture and tensile properties of the laser directed energy deposited (L-DEDed) Ni-based superalloy. This study adopted three levels of energy input from low, medium to high evaluated by the areal energy density to fabricate GH4169 alloy. Results show that a synchronously enhanced strength-ductility of L-DEDed GH4169 Ni-based superalloy with the the high energy input, although the microstructure exhibits the largest grain size and most significant Laves phase size and fraction. This synchronously enhance strength-ductility of L-DEDed GH4169 with high energy input can be mainly attributed to the combined effect of texture variation and residual stress. The crystallographic characterization depicted a texture variation from the {001} <100> cube texture with low energy input to the {111} <110> Goss texture with high energy input, which can be quantitatively analyzed by the average Schmid factor for slip and twinning derived from the “Texture parameters (TP)”. In this case, the average Schmid factor for slip and twinning of the tensile specimen with high energy input are both the smallest, which enhances the yield strength and deformation twinning of the specimen. The microstructure observations showed that the texture variation of the L-DEDed samples from low to high energy input was dominated by the “maximum deviation angel θd” of dendrites determined by the melt-pool shape and related heat-dissipation direction. Besides, the residual stress decreases as the energy input increases, which also contributes to the enhanced strength-ductility with high energy input.

Interpretable sparse identification of a bistable nonlinear energy sink

Bistable nonlinear energy sinks have received great interest due to their efficient broad-band targeted energy transfer over a wide range of input energy levels. The precise identification of bistable nonlinear stiffness force is of significance to predict and enhance the system performance of the vibration energy absorption. However, the nonlinear stiffness force in nonlinear energy sink structures with local bistability is difficult to measure and identify because of snap-through characteristics. Inspired by physics-informed data-driven regression in machine learning, an interpretable sparse identification method is proposed to determine the stiffness force of a bistable nonlinear energy sink. The restoring force surface is constructed on bistable nonlinear energy sink equations and the nonlinear stiffness force trajectory is intercepted by assuming two quasi-zero velocity planes. Furthermore, the candidate functions in the sparse regression algorithm can be physically informed by conducting the least-squares parameter fitting of the intercepted nonlinear stiffness force trajectories. Numerical investigations demonstrate that the proposed method not only gives physics information but also improves the accuracy by 0.48%, 3.26% and 22.21% under the noise level of 30 dB, 20 dB, and 10 dB, respectively. Moreover, the reconstructed dynamic response has a good agreement with the theory. Experimental measurements are performed on a magnetically coupled bistable nonlinear energy sink. Results show that the accuracy improves by 4.52% and 11.76% compared to restoring force surface and Hilbert transform-based methods, respectively.

Competing constraints shape the nonequilibrium limits of cellular decision-making

Gene regulation is central to cellular function. Yet, despite decades of work, we lack quantitative models that can predict how transcriptional control emerges from molecular interactions at the gene locus. Thermodynamic models of transcription, which assume that gene circuits operate at equilibrium, have previously been employed with considerable success in the context of bacterial systems. However, the presence of ATP-dependent processes within the eukaryotic transcriptional cycle suggests that equilibrium models may be insufficient to capture how eukaryotic gene circuits sense and respond to input transcription factor concentrations. Here, we employ simple kinetic models of transcription to investigate how energy dissipation within the transcriptional cycle impacts the rate at which genes transmit information and drive cellular decisions. We find that biologically plausible levels of energy input can lead to significant gains in how rapidly gene loci transmit information but discover that the regulatory mechanisms underlying these gains change depending on the level of interference from noncognate activator binding. When interference is low, information is maximized by harnessing energy to push the sensitivity of the transcriptional response to input transcription factors beyond its equilibrium limits. Conversely, when interference is high, conditions favor genes that harness energy to increase transcriptional specificity by proofreading activator identity. Our analysis further reveals that equilibrium gene regulatory mechanisms break down as transcriptional interference increases, suggesting that energy dissipation may be indispensable in systems where noncognate factor interference is sufficiently large.

Variable-potential bistable nonlinear energy sink for enhanced vibration suppression and energy harvesting

A variable-potential bistable nonlinear energy sink coupled electromagnetic harvesters (VBNES-EH) is proposed, that can simultaneously achieve high efficiency, broadband vibration suppression and energy harvesting under ultra-low and ultra-wide input energy level excitation. The performance is enhanced by introducing two horizontal energy harvesters (HEHs) to dynamically reduce the potential barrier height of the bistable nonlinear energy sink (BNES) or called bistable energy harvester (BEH) to form lower excitation thresholds of the chaotic and strong modulated responses. Firstly, the dimensionless mathematical model of the VBNES-EH is proposed and verified by the experiment. The experimental results are qualitatively consistent with the simulation results. The transient dynamics and the corresponding energy dissipation rates of five target energy transfer (TET) mechanisms for the weakly damped system are summarized numerically. The variable-potential energy effect and its benefits for the dual functions of vibration suppression and energy harvesting are analyzed. Afterward, the stiffness of the VBNES-EH and the fixed-potential BNES-EH (FBNES-EH) are optimized, and their energy dissipation rates under impact excitation are compared. The results indicate that the former has better performance under low- and intermediate-level impact excitations. Furthermore, the influence of system parameters on the energy harvesting rate is discussed to guide the optimal design of the performance. Finally, the dynamical evolution of the VBNES-EH and the parameter effects on the dual performance of the system under harmonic sweep excitation are investigated. Numerical results demonstrate that the VBNES-EH can achieve high performance under the different amplitudes of the harmonic excitation through stiffness optimization.

Changes in Starch In Vitro Digestibility and Properties of Cassava Flour Due to Pulsed Electric Field Processing.

The research aimed to investigate the effect of pulsed electric field (PEF) treatment on cassava flour at mild intensities (1, 2, and 4 kV/cm) combined with elevated levels of specific energy input (250-500 kJ/kg). Influences on starch digestibility, morphological characteristics, birefringence, short-range order and thermal properties were evaluated. Application of PEF at energy input no greater than 250 kJ/kg had negligible influence on the different starch digestion fractions of cassava flour but raised the rapidly digestible starch fraction at a combined electric field strength &gt;1 kV/cm and energy input &gt;350 kJ/kg. Morphological evaluation revealed that at this PEF combination, cassava starch's external structure was consistently altered with swelling and disintegration, albeit some granules remained intact. Consequently, this led to disruption in the internal crystalline structure, supported by progressive loss of birefringence and significantly lower absorbance ratio at 1047/1022 cm-1. These physical and microstructural changes of the inherent starch promoted the shift in gelatinization temperatures to a higher temperature and reduced the gelatinization enthalpy. The study demonstrated that PEF can be utilized to change the starch fraction of cassava flour, which is driven by electric field strength and specific energy input, causing changes in the starch-related properties leading to increased digestibility.

Improving Wetting Behavior and C‐Rate Capability of Lithium‐Ion Batteries by Plasma Activation

Atmospheric corona plasma activation was used at varied energy input levels to modify microsurfaces of cathodes and anodes, previous to assembly into lithium‐ion batteries. Correlations of the plasma activation grade are evaluated considering electrode topography, crystal structure change, electrolyte wetting characteristics, as well as C–rate capability and cycling stability. This reveals upper limits for plasma modification, as well as direct dependencies of possible hydrophilicity changes on electrode composition. Deeper insights into electrochemical impacts are gained by the application of electrochemical impedance spectroscopy, showing changes in C–rate capability to arise from changes in the cathode crystal lattice.

Bistable track nonlinear energy sinks with nonlinear viscous damping for impulsive and seismic control of frame structures

Engineering structures are susceptible to natural and man-made hazards, threatening structural normal functionality and safety. Considerable attention has been paid to the research and development of structural control techniques. Tuned mass dampers (TMDs) are control devices practically applied. However, they only exert the optimum control efficiency in the vicinity of the structural frequency. In contrast, nonlinear energy sinks (NESs) have recently proved robust against potential frequency changes in structures and external excitations, but their control effectiveness is dependent on input energy levels. To this end, a bistable track NES (BTNES) with nonlinear viscous damping is proposed in the present study. The track profile of BTNES is designed as a polynomial combining negative quadratic and positive quartic terms, which correspond to linearly negative stiffness and nonlinearly positive stiffness when an auxiliary mass moves on the curved track. The governing equations of a two-storey frame structure with BTNES subjected to impulsive loads are first derived. The track profiles and damping coefficients of BTNES are optimized for different viscous damping exponents. Then the control performances of BTNES are systematically investigated under various impulsive velocities, structural frequencies, and near-fault and far-field earthquake ground motions. The BTNES performances are also compared to those of a linear TMD and a traditional track NES with only a quartic profile. The results indicate that BTNES with a large viscous damping coefficient has superior control performances in terms of effectiveness, robustness, and damper stroke, which highlights that BTNES has promising applications in protecting structural safety against multiple dynamic hazards.

Design of the proton injector for compact neutron source DARIA

Project of the proton accelerator-driven compact neutron source DARIA (Dedicated for Academic Research and Industrial Application) is developed in order to replace small and middle flux neutron sources based on the nuclear reactors. DARIA has a uniquely high ratio of efficiency to cost due to deep optimization of each key element of the system (proton injector and accelerator, target, neutron moderator and neutron instruments. A unique ECR ion source, developed at the IAP RAS, would be used as a proton beam injector. In such device the plasma is heated by the powerful 28 GHz gyrotron radiation, providing a record level of volumetric energy input for such systems over 100 W/cm^3. The high plasma density and the optimal electron temperature provide proton beams formation with a current of up to several hundred mA and an emittance that meets the requirements of modern accelerators. The paper discusses the advantages of using such an ion source, its scheme and design performance.

Development of novel track nonlinear energy sinks for seismic performance improvement of offshore wind turbine towers

High-rise and flexible offshore wind turbines (OWTs) are frequently constructed in high-seismicity regions, and passive linear control strategies are commonly adopted to mitigate the seismic responses of OWTs. However, the effectiveness of linear control devices is often sensitive to the frequency contents of seismic motions as well as structural frequencies. Track nonlinear energy sinks (NESs) have recently been proven effective in broadband vibration suppression but also possess amplitude-dependent control performance. Two novel NESs with newly-designed track profiles combining quadratic and quartic polynomials are proposed in the present study to improve the effectiveness of track NESs. One (hybrid track NES) combines nonlinear and linear positive stiffness, whereas the other (bistable track NES) combines nonlinear positive and linear negative stiffness. A statistical linearization technique is adopted to optimize the profiles and damping coefficients of the track NESs. A 3D finite element model of a typical OWT is established, and the restoring force composition of the track NESs is analyzed to simplify their numerical modeling. The effectiveness and robustness of the hybrid and bistable track NESs in OWT vibration control are systematically investigated under a set of synthetic and real ground motions considering different structural frequencies and further compared to the tuned mass damper (TMD) and the traditional track NES with a fourth-order polynomial profile. Numerical results show that hybrid and bistable track NESs outperform their counterpart of the traditional track NES. NESs exhibit a robust behavior against frequency changes despite their slightly less control effectiveness than that of the TMD. Moreover, large response reductions are achieved using the bistable track NES under low and moderate input energy levels.

Dimensionless parameters to define process windows of selective laser melting process to fabricate three-dimensional metal structures

Despite the intense research attention on the three-dimensional printing of metal structures via selective laser melting, a unified understanding of thermal conditions, and more specifically the input energy levels, necessary for minimizing macroscopic-defect generation is still lacking. Although simple and widely used parameters, such as linear or volumetric energy density, can be utilized to represent the characteristic energy level of the process, notable differences in printed morphologies and microstructures are observed in structures fabricated at the same energy density. Consequently, designing a process in terms of laser power and scan speed is largely based on trial-and-error approaches. In this work, based on the dimensional analysis of reported experimental data and numerical computation, the process windows suitable for the fabrication of single tracks were examined for various metals. In addition to the normalized enthalpy that quantifies the input energy level, another dimensionless parameter which measures the thermal penetration depth relative to the thickness of powder layer was found to be critical in defining the process window that resulted in acceptable single-track structure formation. To confirm the validity of the analysis, via the elimination of uncertainties and ambiguities inherent to the empirical data, numerical computations were conducted for single-track fabrications using Ti–6Al–4 V and 316L stainless steel alloys. The results of the numerical simulations showed good agreement with the findings obtained from the empirical data.