Basis Of Energy Conservation Research Articles

Fractional scaling analysis of cladding temperature in large break loss of coolant accident

In integral test facilities, some phenomena relevant in the separate effect test are usually neglected due to scaling limitations and design compromises. The typical heat transfer phenomenon in reactor core in large break loss of coolant accident (LBLOCA) scenario is analyzed with fractional scaling analysis (FSA) method in this work. A conservation form of cladding temperature is derived on the basis of energy conservation. Then the scaling criteria and their importance are evaluated. It is found that the similarities of the criteria for convection heat transfer and heat accumulation should be guaranteed since their priorities are high. The contribution of initial pressure and distribution of coolant inventory to cladding temperature in LBLOCA scenario is too slight. This work is encouraging and may shed a light on the coupling application of hierarchical two-tiered scaling (H2TS) and FSA method in engineering application.

Design of Intelligent Street Lamp Control System

Design of Intelligent Street Lamp Control System

Modeling and Verification of Rolling Resistance Torque of High-Speed Rubber Track Assembly Considering Hysteresis Loss

Due to the viscoelasticity of rubber materials, hysteresis loss due to deformation is the main reason for the rolling resistance of high-speed rubber tracks. Since the structure and material of high-speed rubber track assemblies are different from traditional tires and metal tracks, the rolling resistance theory of traditional wheeled and tracked vehicles is not applicable. Therefore, in order to determine the rolling resistance scientifically and accurately, the mechanism research of the rolling resistance of high-speed rubber track assembly is the key to the design of high-speed rubber crawler vehicles. In this paper, the stress-strain characteristics of rubber track under the action of compression, tension, bending, and driving were studied. The strain load spectrum of rubber tracks was established, and the strain cyclic load was extracted by the rainflow method. The temperature model of the rubber track was developed based on its dynamic characteristics. On the basis of energy conservation, the hysteresis loss of rubber is equivalent to the energy consumption of rolling resistance, and the theoretical model of rolling resistance of high-speed rubber track assembly is established. In accordance with the model above, the key influencing factors and changing trends of rolling resistance are analyzed, which provides a theoretical basis for the performance optimization of high-speed rubber track assembly.

A theoretical model for predicting the surface topography of inhomogeneous materials after shot peening

Shot peening is widely used in engineering as a classical strengthening process. Although many studies on shot peening have been done, most have focused on homogeneous target materials. In this paper, a theoretical model is proposed for predicting the surface morphology of inhomogeneous target materials. The topography of target materials after single-shot impact is calculated on the basis of energy conservation and Hertz contact theory, and the final three-dimensional surface topography after multiple-shot impact is obtained through superposition. Single-shot and random multiple-shot finite element models are used to show the advantages of the proposed model over the existing theoretical model for homogeneous target materials. The roughness is found to increase with the shot velocity and shot radius.

Real time prediction method of energy consumption of geothermal system in public buildings based on wavelet neural network

Real time prediction of energy consumption is the basis of energy conservation and emission reduction. Aiming at the problems of large prediction error and poor effect, a real-time prediction method of energy consumption of geothermal system of public buildings based on wavelet neural network is proposed. Firstly, the energy consumption of geothermal system in public buildings is analyzed, the wavelet neural network is designed, the neural network is optimized and solved by genetic algorithm, and the necessity of constructing the real-time prediction model of energy consumption based on wavelet neural network is established. Then it introduces the basic principle of model establishment, wavelet analysis, and shows the role of wavelet analysis in prediction model. Finally, based on the distribution structure of public buildings, this paper analyzes the energy consumption system of geothermal system, constructs the energy consumption prediction method, analyzes the over?all temperature regulation energy consumption prediction principle of building geothermal system, and realizes the real-time prediction of energy consumption of geothermal system of public buildings. The experimental results show that the energy consumption real-time prediction results of the designed method are basically similar to the actual prediction values, and the prediction efficiency is high, which can effectively reduce the energy consumption of the geothermal system of public buildings.

Research and Exploration of Ecological Highway Carbon Sequestration Forest Methodology

Based on the demand of ecological highway construction, this paper explores the research work of carbon sequestration forest. The introduction of forest carbon sinks and advanced concepts of the forestry carbon sequestration, and for the measurement of the highway in the carbon sink forest carbon sink monitoring and exploration on the aspects, such as, the forest carbon sinks and forestry carbon sink theory knowledge, used in highway transportation, implements the carbon sink forest methodology used in the field of traffic, road area change ever green landscape, the shrub tree species as the main design concept, put forward the concept of carbon sequestration in the road system and based on the neutral roadside greening design forestry carbon sequestration. On the basis of energy conservation and emission reduction, the construction of carbon sequestration forest is adopted to solve the carbon emission problem of the transportation industry from another perspective, so as to improve the quality of planting trees along the transportation lines of Jiangsu province and even the whole country, update the greening concept, enhance carbon sequestration and ecological efficiency, and open up a new path for building a green transportation environment.

Possible instability of the Fermi sea against surface plasma oscillations

We derive a generic formalism for studying the energy conversion processes in bounded metals. Using this formalism we show that in the collision-less limit the Fermi sea of metals should experience an instability against surface plasma oscillations, which opens for the latter an intrinsic self-amplification channel. The origin of the instability is clarified as arising from novel effects resulting from the translation symetry breaking due to the very presence of surface. The amplification rate of this channel is analytically evaluated on the basis of energy conservation and the effects of losses are discussed. In particular, the unique role played by the surface in energy conversion is unveiled. In contrast with common wisdom and in line with observations, Landau damping is shown as always overcompensated and therefore poses no serious issues in sub-wavelength plasmonics.

An Entrained-Droplet Model for Prediction of Minimum Flow Rate for the Continuous Removal of Liquids From Gas Wells

Summary Experimental studies show that liquid drop is deformed from initial spherical shape into ellipsoid shape in annular-mist flow, and the available critical Weber number WeCrit determined by the experiment can vary from 2.2 to 60 for low-viscosity liquid. On the basis of the force equilibrium and the critical-Weber-number-calculation method proposed by Azzopardi (1985), this paper develops a new model to predict minimum gas rate. This model introduces a parameter Ck,Wecrit that describes the effect of liquid-drop deformation and the maximum drop-size difference on the minimum gas rate. The effect of liquid-droplet coalescence is also considered indirectly. A function to predict drop-deformation magnitude for different critical Weber numbers is developed on the basis of energy conservation. The function-prediction results are in good agreement with experimental data from the literature and the predicted result from the drop deformation/breakup model, and the average absolute deviation is 6.1%. The Ck,Wecrit calculated by the new model increases with the increase of the pressure and liquid amount and it varies from 3.99 to 7.3, which means the critical gas velocity increases with the increase of the pressure and liquid amount. Numerous gas-well data were used for the validation of these entrained models, including data from 33 low-pressure gas wells (wellhead pressure: 0.26–3.41 MPa) from Coleman et al. (1991) and 91 high-pressure gas wells (wellhead pressure: 0.7–56 MPa) from Turner et al. (1969). The result shows the new entrained model has a good comprehensive performance in judging liquid-loading status in both high- and low-pressure gas wells.

The Design of Power Quality Online Monitor Device under Smart Grid

With the development and construction of smart grid, more and more attentions have been paid to the detection of power quality. Study the disadvantages of wired communication network, applied wireless sensor network technology to power quality online monitoring system. Introduced the hardware and software architectures, designed the detection node and gathering node based on CC2430 and LPC2214 respectively, introduced the establishing process and algorithms of WSN based on ZigBee technology. Experimental results show that, the system can remotely monitor power quality of monitoring points on the power grid, can optimize the power grid operation, and provide enterprises with a reliable basis for energy conservation and emissions reduction.

A multilevel coordinated control strategy for energy conservation in wastewater treatment plants

Wastewater treatment is an energy-intensive process pursuing two objectives: pollution abatement and energy conservation. To achieve these goals automatic control must be applied. This paper describes the performance improvement obtained by the coordinated automation of some basic process operations. Starting with the basic dissolved oxygen control, coordinated control actions are then introduced and their performance assessed. After discussing the design alternatives, the performance of the best combination is selected on the basis of energy conservation, provided that the effluent quality meets the environmental standards. It is shown that a combination of properly tuned PID and fuzzy regulators considerably improves the energy efficiency of the process.

Vibrational Energy Dynamics of Normal and Deuterated Liquid Benzene

Ultrafast Raman spectroscopy with infrared (IR) excitation is used to study vibrational energy dynamics of ambient temperature liquids benzene and benzene-d(6). After IR pumping of a CH-stretch or CD-stretch parent excitation, the redistribution of vibrational energy is probed with anti-Stokes Raman. Ten benzene or 12 benzene-d(6) vibrations out of 30 total have large enough cross sections to be observed. The pathways, quantum yields, and lifetimes for energy transfer among these vibrations are quantified. Using a CCl(4) molecular thermometer, we demonstrate an ultrafast Raman calorimetry method which allows measurement of the rate that benzene vibrational energy is dissipated into the bath. On the basis of energy conservation, we then determine the time-dependent dissipation of aggregate vibrational energy from the unobserved, "invisible" vibrations. During the approximately 1 ps IR excitation process, vibrational energy is coherently redistributed to several vibrational modes ("coherently" means the rate is faster than (T(2))(-1) of the pumped transition). This energy is then further redistributed in an incoherent intramolecular vibrational relaxation process with a 6 ps T(1) time constant. The subsequent dynamics involve energy transfer processes accompanied by vibrational energy dissipation to the bath. This vibrational cooling process has a half-life of 30 ps in benzene and 20 ps in benzene-d(6), and thermalization is complete in approximately 100 ps. The observed strongly Raman-active vibrations have about the same amount of energy per mode as the invisible vibrations. The invisible vibrational energy in benzene decays somewhat faster than the observed energy. These two decay rates are about the same in benzene-d(6).

Dynamics of a rope as a rigid multibody system

A preliminary discrete model of a rope is considered both as a scleronomic and a rheonomic system. Numerical experiments are performed and advantages of the applied algorithm are discussed on the basis of energy conservation. The problem of discretization of the rope is presented in terms of efficient computational simulations. A wave-like effect is discussed with regard to energy transfer and velocity of the model tip. The next directions of the model development are outlined.

Polymer translocation out of planar confinements

Polymer translocation in three dimensions out of planar confinementsis studied in this paper. Three membranes are located atz = −h,z = 0 and z = h1. These membranes are impenetrable, except for the middle one atz = 0, which has a narrow pore. A polymer with lengthN is initially sandwiched between the membranes placed atz = −h and z = 0 and translocates through this pore. We consider strong confinement (smallh),where the polymer is essentially reduced to a two-dimensional polymer, with a radius of gyration scalingas Rg(2D)∼Nν2D;here, ν2D = 0.75 is the Flory exponent in two dimensions. The polymer performs Rouse dynamics. On the basisof theoretical analysis and high-precision simulation data, we show that in the unbiased caseh = h1, thedwell time τd scales as N2+ν2D, in perfect agreement with our previously published theoretical framework. For, the situation is equivalent to field-driven translocation in two dimensions. We show that in this caseτd scalesas N2ν2D, in agreement with several existing numerical results in theliterature. This result violates the earlier reported lower boundN1+ν forτd forfield-driven translocation. We argue, on the basis of energy conservation, that the actual lower boundfor τd isN2ν andnot N1+ν. Polymer translocation in such theoretically motivated geometries thus resolves some ofthe most fundamental issues that have been the subject of much heated debate in recenttimes.

Carrier Multiplication in InAs Nanocrystal Quantum Dots with an Onset Defined by the Energy Conservation Limit

Carrier multiplication (CM) is a process in which absorption of a single photon produces not just one but multiple electron-hole pairs (excitons). This effect is a potential enabler of next-generation, high-efficiency photovoltaic and photocatalytic systems. On the basis of energy conservation, the minimal photon energy required to activate CM is two energy gaps (2Eg). Here, we analyze CM onsets for nanocrystal quantum dots (NQDs) based upon combined requirements imposed by optical selection rules and energy conservation and conclude that materials with a significant difference between electron and hole effective masses such as III-V semiconductors should exhibit a CM threshold near the apparent 2Eg limit. Further, we discuss the possibility of achieving sub-2Eg CM thresholds through strong exciton-exciton attraction, which is feasible in NQDs. We report experimental studies of exciton dynamics (Auger recombination, intraband relaxation, radiative recombination, multiexciton generation, and biexciton shift) in InAs NQDs and show that they exhibit a CM threshold near 2Eg.

Photoacoustic determination of the plasmon enhanced electric field at a corrugated metal interface

The intensity of the optical electric field in the vicinity of a corrugated Ni interface is evaluated in the presence of surface plasmons. A photoacoustic technique is used to measure the energy absorbed by the sample which together with a simultaneous conventional measurement of reflectance allows determination of the total energy flow into and out of the interface. The value of the optical electric field is then evaluated on the basis of energy conservation and found to be intensified by a factor of 2.5 as surface plasmons are resonantly generated.

Basic approach to AC losses in HTS wires exposed to various types of electromagnetic configuration

AC loss in superconducting materials can be estimated, in general, by considering Poynting's vector, electromagnetic power flow, on a closed surface surrounding the sample in a cyclic electromagnetic environment. On the basis of energy conservation, the total amount of the power flow that penetrates into the sample during the period of the electromagnetic environment is equivalent to the AC loss. By using this basic concept of the AC loss, errors in AC loss measurement with three types of pickup coil methods are first considered in relation with the geometrical configuration of the sample coil and the pickup coils. It is indicated from the analytical formulation of the AC loss measured that the error is strongly affected by the arrangement of the cancel coil and that the most proper arrangement is the coaxial type, where the sample coil is set coaxially and concentrically between the inner cancel coil and the outer main pickup coil. Secondly, the geometrical error in a simple method proposed to measure various types of AC loss is also discussed. It is suggested by the analytical consideration that this method has a high accuracy in the AC loss measurement even in comparison with the coaxial type of pickup coil method. Finally, experimental results measured by the simple method for various types of AC loss in Bi-2223 tapes are compared with numerical simulation with the measured E– J characteristic.

Thermodynamic constraints on reflectance reciprocity and Kirchhoff’s law

Contrary to common belief, neither reciprocity of the bidirectional reflectance distribution function (BRDF) nor the directional form of Kirchhoff's electromagnetic radiation law can be demonstrated on the basis of energy conservation. The BRDF is generally considered reciprocal as an extension of Helmholtz reciprocity, but Helmholtz reciprocity does not always hold. We describe the flaw in a thermodynamic demonstration of reciprocity that uses an enclosure calculation. Some conclusions can be drawn from the enclosure calculation, but reciprocity requires more restrictive conditions. We conclude that, although they can be violated, reciprocity and the directional form of Kirchhoff's law generally hold because of the quantum-mechanical principle of time-reversal invariance, which applies to most materials.

On the concept of energy in classical relativistic physics

The relativistic concept of energy is discussed under two important aspects: the behaviour of the energy under coordinate transformations and its general definition in the presence of external gravitational and electromagnetic fields. On the basis of energy conservation and a nonrelativistic approximation it is argued that only the zeroth component of the covariant 'generalized' momentum should be called 'energy'.

Causes and rate‐limiting mechanisms of ridge propagation: A fracture mechanics model

All known propagating rifts (PR's) are growing away from shallow ridge axis seafloor. We examine a model for rift propagation in which the ridge axis conduit, like a crack in the lithosphere, propagates in response to a stress concentration at its tip. The stress concentration near the tip which causes progressive failure of the lithosphere is primarily due to excess gravity‐spreading stresses associated with anomalously shallow ridge axis along the growing ridge. This stress concentration near the tip is characterized by a stress intensity factor K, which must exceed a threshold value to cause failure of the plate. A remotely applied tensile stress would make a positive contribution to K but would act equally on both ridge segments and not favor the propagation of either. The pressure in the crack may, depending on its distribution, make either a positive or negative contribution to K. For a high enough propagation rate, viscous flow induced suction due to the growth of the ridge axis as well as the reduced vertical flow near the PR tip would make K < 0. This simple model thus includes a mechanism to control the speed of propagation and is consistent with the axial morphology of the spreading segment associated with the well‐studied 95.5°W PR of the Galapagos spreading center. Analytical solutions for the contribution to the stress intensity factor of viscous forces resisting ridge axis growth and causing the PR axial topography are consistent with the observed propagation rate for asthenosphere viscosities of about 1019 Pa s (1020 P). We also examine a more general model of a ridge‐transform‐ridge system on the basis of energy conservation. In terms of energetics this more general model reduces to that of a single propagating ridge axis crack when both the work done by forces driving propagation and the viscous dissipation due to forces resisting propagation are generated along the growing ridge axis. However, the more general model also includes mechanisms that may stop ridge propagation. Propagation will stop either when the energy needed for transform migration is larger than that available for ridge axis growth or when the strain energy absorbed at the dying ridge axis is comparable to that released at the growing ridge axis, i.e., if the stress intensity factors for both ridge axes are similar. Both of these possibilities may occur when the propagating rift completely propagates through a ridge segment as at 85°W in the Galapagos. Finally, in this model the slight systematic differences in ridge axis orientation of the growing and dying ridges are a consequence rather than a cause of ridge propagation.

Optical electric-field enhancement at a metal surface arising from surface-plasmon excitation

Surface plasmons can be excited on a metal by an external plane-wave beam through the use of prism or grating couplers or by introducing roughness. This can enhance the electric field at the surface compared with that in the incident beam, and it has been suggested that this effect is an important aspect of surface-enhanced Raman scattering. A general upper limit for this field enhancement is derived on the basis of energy conservation. Numerical results are given for Ag, Au, and Cu. With a perfect coupler on a Ag surface, the maximum increase of the square of the electric field in the 2-3-eV range is congruent with300. On randomly roughened surfaces, the estimated enhancements are of the order of unity.