Energy Loss Characteristics Research Articles

Ion energy-loss characteristics and friction in a free-electron gas at warm dense matter and nonideal dense plasma conditions.

We investigate the energy-loss characteristics of an ion in warm dense matter (WDM) and dense plasmas concentrating on the influence of electronic correlations. The basis for our analysis is a recently developed ab initio quantum Monte Carlo- (QMC) based machine learning representation of the static local field correction (LFC) [Dornheim et al., J. Chem. Phys. 151, 194104 (2019)JCPSA60021-960610.1063/1.5123013], which provides an accurate description of the dynamical density response function of the electron gas at the considered parameters. We focus on the polarization-induced stopping power due to free electrons, the friction function, and the straggling rate. In addition, we compute the friction coefficient which constitutes a key quantity for the adequate Langevin dynamics simulation of ions. Considering typical experimental WDM parameters with partially degenerate electrons, we find that the friction coefficient is of the order of γ/ω_{pi}=0.01, where ω_{pi} is the ionic plasma frequency. This analysis is performed by comparing QMC-based data to results from the random-phase approximation (RPA), the Mermin dielectric function, and the Singwi-Tosi-Land-Sjölander (STLS) approximation. It is revealed that the widely used relaxation time approximation (Mermin dielectric function) has severe limitations regarding the description of the energy loss of ions in a correlated partially degenerate electrons gas. Moreover, by comparing QMC-based data with the results obtained using STLS, we find that the ion energy-loss properties are not sensitive to the inaccuracy of the static local field correction (LFC) at large wave numbers, k/k_{F}>2 (with k_{F} being the Fermi wave number), but that a correct description of the static LFC at k/k_{F}≲1.5 is important.

Quantitative Analysis of Left Ventricular Flow Dynamics in Latent Obstructive Hypertrophic Cardiomyopathy Using Vector Flow Mapping

Objectives: This study aimed to assess left ventricular (LV) energy loss (EL), circulation and vortex area using vector flow mapping (VFM) in patients with latent obstructive hyper­trophic cardiomyopathy (LOHCM) and nonobstructive hypertrophic cardiomyopathy (NOHCM). Methods: Fourteen LOHCM patients, 10 NOHCM patients, and 11 healthy individuals were evaluated by transthoracic echocardiography. An offline VFM workstation was used to analyze the LV blood flow patterns and fluid dynamics. The hemodynamic parameters, EL, circulation, and vortex area in 7 cardiac phases were calculated and analyzed. Results: Compared with controls and NOHCM patients, EL was significantly higher in ­LOHCM patients during the rapid ejection phase, slow ejection (SE) phase, and isovolumetric relaxation phase (p < 0.05). LOHCM patients also showed increased circulation during SE compared to the other two groups (p < 0.05). The ability to discriminate between NOHCM and LOHCM was assessed by the area under the receiver-operating characteristic curve (AUC), and EL during SE was found to have the largest AUC (0.964); the best cutoff value was 6.34 J/m³/s, with a sensitivity of 100% and specificity of 80%. Conclusions: The VFM technique can detect abnormal changes of LV EL and vortex characteristics in hypertrophic cardiomyopathy patients. Compared with controls and NOHCM patients, the LOHCM patients have worse systolic and diastolic functions.

3D numerical investigation of energy transfer and loss of cavitation flow in perforated plates

ABSTRACT Perforated plates are prevalently used in various integrated energy systems for flow restriction, vibration, and noise reduction. The characteristics of flow energy transfer and loss in perforated plates have a significant impact on its piping systems. The existing design and previous studies largely paid little attention to the characteristics of flow energy variation, resulting in severe performance issues and energy consumption. In this study, the characteristics of energy transfer and loss of cavitation flow with various pressure ratios in single and multi-stage perforated plates were numerically studied. The parameters of energy ratio and energy gradient were developed to effectively evaluate the degree and rate of flow energy variation. Results showed that the contribution to energy loss generated from orifice outlet was relatively larger than the inlet and that the degree and rate of energy variation deceased with the increasing stages during the flow in multi-stage models. Additionally, increased stages of perforated plate resulted in a multi-stage stepped energy drop in throttling orifices, and lead to obvious suppression of the cavitation. This work intends to provide references to cavitation control and energy consumption optimization in piping systems using a perforated plate.

Specific aspects of forecasting electrical energy losses in electricity networks

The present paper considers methods of predicting load losses under varied types of electrical energy loss characteristics. The method of forecasting electrical energy losses with the use of one-factor (planned electrical supply to network) and multi-factor (planned values of electrical supply to network, energy output from electric power stations, etc.) characteristics of power and energy losses is proposed. Static models of nodal loads and parameters of equivalent network are used. The paper substantiates the application of multi-factor characteristics for assessing electrical energy losses during regulatory period. The paper provides the solution of the system of nonlinear equations describing long-term balance plans for electrical energy and gives the results of predicting load losses of electrical energy.

Differences in Mechanical Midsole Characteristics of Running Shoes do not Influence Physiological Variables in Aerobic and Anaerobic Running.

The purpose of this study was to determine the influence of footwear stiffness and energy loss on oxygen uptake and heart rate in athletes running under aerobic and anaerobic conditions. Four footwear conditions with identical outsoles, insoles, upper materials, but different mechanical properties regarding polyurethane midsole materials were investigated. Respective midsole material characteristics were selected to represent a wide range of running shoes. The test procedure for eighteen well‐trained male runners was divided into three treadmill testing sessions: an incremental ramp protocol to estimate the individual ventilatory threshold (day 1), a test with 6‐minute stages in each shoe at 70% (aerobic, day 2) and 102% (anaerobic, day 3) of the participant’s ventilatory threshold. For oxygen uptake and the heart rate, no significant differences between footwear conditions were found for either running condition. Furthermore, no significant relationships between physiological variables and mechanical midsole characteristics were found. The wide range of significant stiffness differences in the rearfoot (52.7 N/mm) and forefoot areas (50.7 N/mm), as well as significant differences of the shoe midsole material energy loss in the rearfoot (18.8%) and forefoot areas (10.7%) were too low to influence physiological variables significantly when running below and slightly above the ventilatory threshold. It seems that shoe mass and shoe comfort can influence physiological variables more than the mechanical midsole characteristics of stiffness and energy loss. These results may have practical implications for shoe manufacturers, coaches, and athletes, alike.

Quantification of fatigue damage at dry–wet cycles of polymer fiber cement mortar

Abstract Dry–wet cycles on cement has brought huge potential safety hazards of some high geothermal diversion tunnel every year. However studies for wet and dry conditions under temperatures on cement-based materials are still rare due to the special environment. The difficulty in qualitative evaluation of fatigue damage of polymer fibrous mortars lies in the properties of varying strength and plastic deformation. In this paper, an attempt was made to quantify repeated dry–wet cyclic performance of fibers mortars by using the concept of irreversible plastic fatigue energy. Attention was paid to the strength and strain of polymer fibers mortars specimens under dry–wet cycles. Starting from the fact that the stress curve governs the energy-loss characteristics of mortars subjected to dry–wet cycles were determined by calculating the irreversible plastic fatigue strain increment of dry–wet cycles. These parameters made it possible to estimate the fatigue damage of polymer fibers mortars.

Effect of coupling agents on the vulcanizate structure of carbon black filled natural rubber

ABSTRACTEnergy loss in carbon black (CB) filled vulcanizates can be reduced by decreasing the CB volume fraction, reducing the localized deformation of rubber molecules between low-structure CB fillers, and increasing the crosslink density of vulcanizates. However, the decreased volume fraction and the use of low-structure CB degrade the mechanical properties of the vulcanizate. Furthermore, the increased crosslink density leads to drawbacks, such as the decrease of dynamic fatigue property. In this study, considering the performance trade-off from the energy loss reduction of CB-filled vulcanizate, the CB coupling agents (CCAs) system was introduced and its vulcanizate structure and mechanical properties were investigated. The coupling effect between CCAs and natural rubber molecules was confirmed by analyzing the vulcanizate structure using Flory–Rehner and Kraus equations. The vulcanizates with CCAs showed an increase in total crosslink density (TCD) compared to vulcanizates without CCAs. This increased TCD was attributed to the increase in crosslink density by the CB–rubber interaction (CRCD) and the increase in crosslink density by vulcanization reactions between vulcanization agents and matrix rubber (VRCD). The increase of TCD by CCAs improved the mechanical properties of vulcanizates. In particular, the energy loss characteristics were improved by increasing CRCD.

The Effect of Bead Shape and Texture on the Energy Loss Characteristics in a Rotating Capsule

Energy loss characteristics in a rotating bead-filled capsule are impacted by bead shape, size, surface texture, density, and capsule fill level. In this paper, the energy loss results are reported from experiments of bead-filled cylindrical capsules rolling down a ramp in a controlled manner without sliding. These experiments were motivated by the potential applications of bead-filled capsules for energy dissipation and vibration control systems, as well as for understanding energy use in rotating drum-based industrial processes. The experiment used a plexiglass cylindrical capsule filled with beads of different sizes, materials, and textures. The bead-filled capsule was rolled down an inclined ramp and came to a stop on a level ramp. The position at which the capsule stopped was recorded. As the capsule rolled down the ramp, the potential energy converted to kinetic energy. When the kinetic energy dissipated, the capsule came to a stop. The distance traveled by the capsule is controlled by the energy loss caused by the collision and the friction of the beads. The nature of the collision and friction of the beads depended on the amount, size, type, and texture of the beads in the cylinder. The data was analyzed to determine the conditions for optimal fill level, which is defined as the case for maximum energy loss. We found that the intermediate filling level had the most energy loss. This optimal filling was obtained for each bead type.The maximum energy dissipation increased with bead surface texture and bead density but decreased with bead size.

Energy loss in nano-dimensional wire structures due to piezoelectric interaction at low temperatures

The theory of energy loss rate of non-equilibrium electrons due to inelastic interaction with intravalley piezoelectric phonons in a nano-dimensional semiconductor wire has been developed under the condition of low lattice temperatures, without recourse to the standard approximations which are usually made when developing theories at relatively higher temperatures. Such approximations are hardly valid when the lattice temperature is low. As expected, compared to the well-known earlier results, the theory here, reveals a complex and altogether different dependence of the energy loss rate upon the carrier energy and the lattice temperature. The numerical results have been obtained for narrow channel wires of GaAs and GaN. On comparison with other available results, it is revealed that the finite energy of piezoelectric phonons and the full form of the phonon distribution bring about quite significant changes in the energy loss characteristics at low temperatures.

Ecological cross section rehabilitation in Fenghui Main Canal

In order to rehabilitate the optimal cross section of the Fenghui main canal, this paper developed some ecological rehabilitation plans based on the original canal cross section and the vegetation is arranged in both boundary and bottom of channel. The physical model test was carried out to study resistance parameters for flow over vegetation. By analyzing the value of section mean roughness under different design schemes, the energy loss and cost corresponding to each reconstruction scheme can be compared. The results show that: based on momentum balance principle and improved hydraulic radius model, the theoretical value and measurements from load cell are quite similar. Meanwhile, the optimal vegetation lay-out in cross section based on smallest energy loss and best hydraulic characteristics can be determined. From the perspective of project cost analysis, it is recommended to select the cross-pavement ecological vegetation scheme from the aspects of hydraulic characteristics and economics.

An image processing method for automated evaluation of the area of hysteresis loops

Measuring the magnetic hysteresis loop and energy loss characteristics of magnetic materials helps students to understand the ferromagnetic properties of the materials. In this study, a conventional experiment is combined with automated image processing to learn about the fundamentals of the hysteresis loop by measuring its area. We process a loop image acquired using a digital camera to calculate the area. The results of this easy and instructive experiment are substantially compatible with theory and are more precise than those obtained when using the tedious conventional method of manually evaluating the loop area. The proposed method is discussed as a clear-cut and a fast tool to reproduce the results with pragmatic accuracy.

Tests and Analysis of a Small-Scale Hybrid-Type DC SFCL Prototype

In recent years, high-voltage dc power transmission is widely developed in the world. However, it is difficult for the existing dc breaker to cut off the fault transmission line with large short-circuit fault current. In a short-circuit fault of dc systems, short-circuit fault current is composed of initial transient impulse current and steady-state fault current. Therefore, a hybrid-type dc superconducting fault current limiter (SFCL) is proposed with two-stage current limiting capability. In the early stage of short-circuit fault, initial transient impulse current is limited by inductance and resistance. In the later stage of short-circuit fault, a sustained and steady current-limiting resistance is provided by the dc SFCL. A small-scale prototype of the dc SFCL is developed and the parameter design of the dc SFCL prototype is presented. According to the experimental tests and simulation analysis, the design scheme's effectiveness can be confirmed from high current-limiting ratio. Based on experimental tests and simulation analysis, the current-limiting characteristics and energy loss characteristics of the hybrid-type dc SFCL have been well verified.

Energy and magnetostriction analysis and nonlinear model of magnetostrictive actuator for precision drive

Magnetic hysteresis and eddy-current heating are the most significant disadvantages in giant magnetostrictive materials (GMM). And these properties have an effect on the displacement precision and other working performances of giant magnetostrictive actuator (GMA). To know and solve these above problems fundamentally, the key point is establishing a mathematical model which can describe magnetisation hysteresis process and energy loss characteristics for GMM and analysing the essential reason which causes hysteresis phenomenon. In this paper, on the basis of Armstrong theory and through analysing the composition of elastic Gibbs free energy, a nonlinear magnetisation and magnetostriction model is established. Experimental results show that this model can predict the magnetisation property, magnetostriction, magnetic potential orientation, energy loss characteristic and other working performance for GMM well. It is also able to describe the magnetostrictive elongation and output displacement for GMM rod and GMA respectively. Research results will provide a theoretical basis for solving magnetic hysteresis, working precision, and eddy current heating for GMA fundamentally.

Modeling and Dynamic Analysis on the Direct Operating Solenoid Valve for Improving the Performance of the Shifting Control System

The dynamic characteristics and energy loss in a shifting control system is important and necessary in the performance improvement of an automatic transmission. The direct operating solenoid valve has been considered as a potential component applying in the shifting control system in vehicle. The previous method can solve only a specific physical field or use the test results of the magnetic force as input curve. The paper presents a numerical approach for solving the multi-domain physical problem of the valve. A precise model of the direct acting solenoid valve considering different physical field is developed. An experimental study is also performed to evaluate and confirm the simulation. Based on the model, the influences on the dynamic characteristics of the valve are analyzed by calculating forces acting on the valve. The systematic analysis of forces and energy loss characteristics are performed for three different flow conditions varying clearance height from 10 µm to 30 µm. The results demonstrate that the pressure response time can be improved with smaller clearance between the spool and the sleeve. Moreover, the leakage of the shifting control system employing the direct acting solenoid valve can be reduced by 60% compared to the conventional two-stage pilot valve in our previous product.

Case Library Construction Technology of Energy Loss in Distribution Networks Considering Regional Differentiation Theory

The grid structures, load levels, and running states of distribution networks in different supply regions are known as the influencing factors of energy loss. In this paper, the case library of energy loss is constructed to differentiate the crucial factors of energy loss in the different supply regions. First of all, the characteristic state values are selected as the representation of the cases based on the analysis of energy loss under various voltage classes and in different types of regions. Then, the methods of Grey Relational Analysis and the K-Nearest Neighbor are utilized to implement the critical technologies of case library construction, including case representation, processing, analysis, and retrieval. Moreover, the analysis software of the case library is designed based on the case library construction technology. Some case studies show that there are many differences and similarities concerning the factors that influence the energy loss in different types of regions. In addition, the most relevant sample case can be retrieved from the case library. Compared with the traditional techniques, constructing a case library provides a new way to find out the characteristics of energy loss in different supply regions and constitutes differentiated loss-reducing programs.

The Dynamic Performance and Thermal Computation of Electromagnetic Rail Launcher Considering Parameters Variation

For the electromagnetic rail launcher, the parameters variation has obvious effect on the dynamic performance and efficiency. This paper constructs the system simulation model of the electromagnetic rail launcher by using of Simulink software, and then analyzes the influences on the system dynamic performance for main devices. Based on the parameters and large current condition, the launching efficiency model is constructed, and the energy distribution characteristics are obtained. The loss of rail, armature, and feeder equipment is 38.7%, and the loss of arc extinguishing equipment is about 4.76%, so the heat loss is about 43.46% of total loss. When considering that the other loss is 33.37%, the system energy efficiency is 23.17%. Based on the design of the small prototype, the energy loss characteristics of the full prototype in launch rail and its temperature features are discussed in detail. The peak temperature is 276 °C after 11 continuous shots with converting coefficient being 5000 W/( $\text{m}^{{{2}}}\cdot \text {K}$ ), and it can decrease 58 °C if the better convection boundary condition is achieved, which means the rail can meet the requirement of the thermal management.

Exploring energy loss by vector flow mapping in children with ventricular septal defect: Pathophysiologic significance

BackgroundVector flow mapping is a novel echocardiographic flow visualization method, and it has enabled us to quantitatively evaluate the energy loss in the left ventricle (intraventricular energy loss). Although intraventricular energy loss is assumed to be a part of left ventricular workload itself, it is unclear what this parameter actually represents. The aim of the present study was to elucidate the characteristics of intraventricular energy loss. MethodsWe enrolled 26 consecutive children with ventricular septal defect (VSD). On echocardiography vector flow mapping, intraventricular energy loss was measured in the apical 3-chamber view. We measured peak energy loss and averaged energy loss in the diastolic and systolic phases, and subsequently compared these parameters with catheterization parameters and serum brain natrium peptide (BNP) level. ResultsDiastolic, peak, and systolic energy loss were strongly and positively correlated with right ventricular systolic pressure (r=0.76, 0.68, and 0.56, p<0.0001, = 0.0001, and 0.0029, respectively) and right ventricular end diastolic pressure (r=0.55, 0.49, and 0.49, p=0.0038, 0.0120, and 0.0111, respectively). In addition, diastolic, peak, and systolic energy loss were significantly correlated with BNP (r=0.75, 0.69 and 0.49, p<0.0001, < 0.0001, and=0.0116, respectively). ConclusionsIn children with VSD, elevated right ventricular pressure is one of the factors that increase energy loss in the left ventricle. The results of the present study encourage further studies in other study populations to elucidate the characteristics of intraventricular energy loss for its possible clinical application.

Magnetostrictive and Kinematic Model Considering the Dynamic Hysteresis and Energy Loss for GMA

Due to the influence of magnetic hysteresis and energy loss inherent in giant magnetostrictive materials (GMM), output displacement accuracy of giant magnetostrictive actuator (GMA) can not meet the precision and ultra precision machining. Using a GMM rod as the core driving element, a GMA which may be used in the field of precision and ultra precision drive engineering is designed through modular design method. Based on the Armstrong theory and elastic Gibbs free energy theory, a nonlinear magnetostriction model which considers magnetic hysteresis and energy loss characteristics is established. Moreover, the mechanical system differential equation model for GMA is established by utilizing D’Alembert’s principle. Experimental results show that the model can preferably predict magnetization property, magnetic potential orientation, energy loss for GMM. It is also able to describe magnetostrictive elongation and output displacement of GMA. Research results will provide a theoretical basis for solving the dynamic magnetic hysteresis, energy loss and working precision for GMA fundamentally.

Clinical Study of Left Ventricle Energy Loss in Patients with Heart Failure with Mid-Range Ejection Fraction by Vector Flow Mapping Technique

1.To evaluate the characteristics of energy loss(EL) in left ventricule by VFM in patients with HFmrEF. 2.Explore the relationship between EL and cardiac structure and function in patients with HFmrEF. The study includes 28 patients with HFmrEF, compared with 23 normals. HFmrEF patients are divided into 2 groups:group I with diastolic dysfunction, group II without diastolic dysfunction. VFM is used to calculate EL in left ventricle in IVR, RFP, ACP, IVC, REP. The EL at RFP, IVC, REP in left ventricle at every phase decrease in the HFmrEF group. Compared with group II,the EL of group I at IVR and RFP increase (P<0.05).The EL at RFP, IVC, REP in left ventricle decrease in the HFmrEF group (P<0.05). Compared with group II,the EL of group I at IVR and RFP increase (P<0.05). Total EL in LV during RFP is independently associated with E/e’ (β= 0.423, P= 0.019).Total EL in LV during ACP is associated with GLS(β= 0.392, P= 0.039).Total EL in LV during IVC is independently associated with GLS (β= 0.546, P= 0.001). In HEmrEF, EL in the left ventricle decreases in RFP, IVC, REP. However, the EL in RFP will increase if accompanied with diastolic dysfunction. The EL in the left ventricle in RFP is related to the diastolic function of the heart, and the EL in ACP and IVC is related to the systolic function of the heart.

Energy loss to intravalley acoustic modes in nano-dimensional wire structures at low temperatures

The theory of rate of loss of energy of non-equilibrium electrons due to inelastic interaction with the intravalley acoustic phonons in a nano-dimensional semiconductor wire has been developed under the condition of low lattice temperature, when the approximations of the well known traditional theory are not valid. Numerical results are obtained for narrow-channel GaAs-GaAlAs wires structures. On comparison with other available results it is revealed that the finite energy of the intravalley acoustic phonons and, the use of the full form of the phonon distribution without truncation to the equipartition law, produce significant changes in the energy loss characteristics at low temperatures.