Transmission Energy Loss Research Articles

Feasibility analysis and application design of a novel long-distance natural gas and electricity combined transmission system

This paper proposed a novel long-distance combined transmission system, in which LNG (liquefied natural gas) is transported in the pipeline and electricity is transmitted through a high-temperature superconducting cable refrigerated by LNG. Through this system, electricity and LNG could be transmitted simultaneously with high efficiency. This paper analyzed the theoretical feasibility of the proposed system and studied the effects of several key parameters on energy transmission loss. The analysis results show that the loss rate of LNG transportation system decreases with the increase of pipe diameter. There is an economic flow velocity with which the minimum loss rate of the LNG transportation system could be achieved. The total loss rate of the combined system decreases with the increase of the transmission capacity ratio of electricity to LNG. Through an application computation, it is found that the transmission efficiency of the combined system can reach up to 96%, and the loss rate is just 58% of that of the conventional systems. Moreover, the power wasted induced by the heat leakage occupies 85.2% of the total power wasted at the cryogenic refrigeration and pump station, which may suggest improving the insulation performance is significant to the transmission efficiency of the combined system.

Influence of dynamic parameters on interacting efficiency between ground-based laser and air-based flying target

We simulate the integrated effects of atmospheric aberration, atmospheric turbulence, thermal blooming, random jitter of laser's intensity and phase, speed of wind, direction of wind, absorption of air, kinetic cooling of CO2 and N2, speed of target, output power and beam quality of laser, wavelength, focus length, and the launch altitude of laser to accurately simulate the transmission loss of the laser's energy, concentration of laser's power and other beam quality parameters of the laser propagating to the dynamic target. And we evaluate the efficiency of laser's irradiation on the target more accurately for the optical link of ground-to-airspace. We also investigate influences of characteristics of dynamic parameters (Strehl's ratio, RMS of wave-front, spatial distribution of intensity on the target, the real focus on the optical link and the peak intensity along the propagation path) including speed of wind, direction of wind, speed of target and the kinetic cooling effect of air, especially. We conclude that the higher speed of wind and target weakens the thermal blooming of atmosphere and improves the beam quality and efficiency of laser's irradiation on the target. The kinetic cooling effect of air is more remarkable to improve the beam quality irradiating on the target at the initial part of the propagation path of the laser. The changed direction of wind weakens the atmospheric aberration and directs to better beam quality and higher efficiency of laser's irradiation on the target.

An analysis of ground shaking and transmission loss from infrasound generated by the 2011 Tohoku earthquake

The 2011 Mw9.0 Tohoku earthquake generated infrasound that was recorded by nine infrasonic arrays. Most arrays recorded a back azimuth variation with time due to the expanse of the source region. We use ray tracing to predict group velocities and back azimuth wind corrections. A Japan accelerometer network recorded ground shaking in unprecedented spatial resolution. We back projected infrasound from arrays IS44 (Kamchatka) and IS30 (Tokyo) to the source region and compare these results with acceleration data. IS44 illuminates the complex geometry of land areas that experienced shaking. IS30 illuminates two volcanoes and a flat area around the city of Sendai, where the maximum accelerations occurred. The arrays and epicentral region define three source‐receiver profiles. The observed broadband energy transmission loss (TL) follows an exponential decay law. The best fitting model, which has parameters that are interpreted to include the effects of geometric spreading, scattering, and the maximum ratio of the effective sound speed in the stratosphere to that at the ground (accounts for stratospheric wind speed), yields a 65% variance reduction relative to predictions from a traditional TL relationship. This model is a simplified version of the model of Le Pichon et al. (2012), which yields an 83% variance reduction for a single frequency, implying that fine‐scale atmospheric structure is required to explain the TL for stratospheric upwind propagation. Our results show that infrasonic arrays are sensitive to ground acceleration in the source region of megathrust earthquakes. The TL results may improve infrasonic amplitude scaling laws for explosive yield.

승용차량의 소음저감을 위한 시험과 시뮬레이션을 이용한 대시 시스템의 특성 연구

Low frequency noises(up to about 200 Hz) such as booming are mainly caused by particular modes, and in general the solutions may be found based on mode controls where conventional methods such as FEM can be used. However, at higher frequencies between 0.3~1 kHz, as the number of modes rapidly increases, radiation characteristics from structures, performances of damping sheets and sound packages may be more crucial rather than particular modes, and consequently the conventional FEM may be less practical in dealing with this kinds of structure-borne problems. In this context, so-called `mid-frequency simulation model` based on FE-SEA hybrid method is studied and validated to reduce noise in this frequency region. Energy transmission loss(i.e. air borne noise) is also studied. A dash panel component is chosen for this study, which is an important path that transmits both structure-borne and air borne energies into the cavity. Design modifications including structural modifications, attachment of damping sheets and application of different sound packages are taken into account and the corresponding noise characteristics are experimentally identified. It is found that the dash member behaves as a noise path. The damping sheet and sound packages have similar influences on both sound radiation and transmission loss. The comparison between experiments and simulations shows that this model could be used to predict the tendency of noise improvement.

2A2-A07 電気静油圧リンク系の力伝達構造に基づく受動的安定化制御(アクチュエータの機構と制御(2))

To achieve high backdrivability in transmission, it is an effective approach to decouple the dynamics of actuators. Electro-Hydrostatic Actuators (EHA) which is modeled as a decoupled dynamics by damping element can achieve high backdrivability. However, accurate modeling of energy loss and damping in hydraulic transmission is difficult, which requires controllers with robustness to modeling error. In this paper, we derive a model of a manipulator actuated by EHA and propose a passivity-based controller for the EHA driven manipulators. The proposed controller consists of PD control and gravity compensation based on link joint angle and velocity feedback. The whole dynamics is composed of two passive subsystems, link and pump dynamics, and asymptotic stability is given. The efficacy of the proposed controller was evaluated by experiment.

The Singapore high resolution single cell imaging facility

The Centre for Ion Beam Applications, National University of Singapore has recently expanded from three state-of-the-art beam lines to five. Two new beam lines have been constructed: A second generation proton beam writing line, and a high resolution single cell imaging facility. Both systems feature high demagnification lens systems based on compact Oxford Microbeams OM52 lenses, coupled with reduced lens/image distances.The single cell imaging facility is designed around OM52 compact lenses capable of operating in a variety of high demagnification configurations including the spaced Oxford triplet and the double crossover Russian quadruplet. The new facility has design specifications aimed at spatial resolutions below 50nm, with a variety of techniques including STIM, secondary electron and fluorescence imaging, and an in-built optical and fluorescence microscope for sample imaging, identification and positioning.Preliminary tests using the single space Oxford triplet configuration have indicated a beam spot size of 31×39nm in the horizontal and vertical directions respectively, at beam currents of ∼10,000 protons per second. However, a weakness in the specifications of the electrostatic scanning system has been identified, and a more stable scanning system needs to be implemented before we can fully realize the optimum performance. A single whole fibroblast cell has been scanned using 1.5MeV protons, and a median fit to the proton transmission energy loss data has shown that proton STIM gives excellent details of the cell structure despite the relatively poor contrast of proton STIM compared with alpha STIM.

Experimentally evaluated impact of nonlinear loads on the energy transmission losses and distortion of voltage waveforms

Experimentally evaluated impact of nonlinear loads on the energy transmission losses and distortion of voltage waveforms

Focal-Plane Change Triggered Video Compression for Low-Power Vision Sensor Systems

Video sensors with embedded compression offer significant energy savings in transmission but incur energy losses in the complexity of the encoder. Energy efficient video compression architectures for CMOS image sensors with focal-plane change detection are presented and analyzed. The compression architectures use pixel-level computational circuits to minimize energy usage by selectively processing only pixels which generate significant temporal intensity changes. Using the temporal intensity change detection to gate the operation of a differential DCT based encoder achieves nearly identical image quality to traditional systems (4dB decrease in PSNR) while reducing the amount of data that is processed by 67% and reducing overall power consumption reduction of 51%. These typical energy savings, resulting from the sparsity of motion activity in the visual scene, demonstrate the utility of focal-plane change triggered compression to surveillance vision systems.

Modelling and simulation of mechanical transmission in roller‐screw electromechanical actuators

PurposeThe purpose of this paper is to develop accurate model and simulation of mechanical power transmission within roller‐screw electromechanical actuators with special attention to friction, compliance and inertia effects. Also, to propose non‐intrusive experiments for the identification of model parameters with an integrator or system‐oriented view.Design/methodology/approachAt system design level, the actuation models need to reproduce with confidence the energy losses and the main dynamic effects. The adopted modelling methodology is based on non‐intrusive measurements taken on a standard actuator test‐bench. The actuator model is first structured with respect to the bond‐graph formalism that allows a clear identification of the considered effects and associated causalities for model implementation. Various approaches are then combined, mixing blocked or moving load, position or torque control and time or frequency domains analysis. The friction representation model is suggested using a step‐by‐step approach that covers a wide domain of operation. The model is validated under varying torque and speed conditions.FindingsA structured model is introduced with support of the bond‐graph formalism. Combining blocked/moving load and time/frequency domain experiments allows the development of progressive model identification. An advanced friction representation model is proposed including the effects of speed, transmitted force, quadrant of operation and roller‐screw preload.Originality/valueMechanical transmission energy losses and dynamics are modelled in a system‐oriented view without massive need to confidential design parameters. Not only speed but also load and operation quadrant effects are reproduced by the proposed friction model. The non‐intrusive experimental procedure is made consistent with use of a standard actuator test‐bench.

Impact of compact fluorescent lamps on energy transmission losses and power quality

Impact of compact fluorescent lamps on energy transmission losses and power quality

Effect of Mesoscale eddies on underwater sound propagation

The effects of sound speed variables induced by an anticyclonic eddy and a field of three cyclonic eddies on long-range sound propagation are investigated respectively. A deep-sea analytical eddy model [Henrick RF, Siegmann WL, Jacobson MJ. General analysis of ocean eddy effects for sound transmission applications. J Acoust Soc Am 1977;62:860–870] is used to determined sound speed distributions produced by warm-core ring in the southwest of South China Sea. Furthermore, the above analytical eddy model is generalize to include the azimuth angle variation and is used to determined sound speed distributions produced by Gulf Stream rings with different strengths. The theoretical temperature fluctuations induced by the warm eddy and a eddy field including three cyclonic eddies agree qualitatively with the in situ investigation data. The transmission loss of acoustic energy through the cross section of the warm-core ring center and three cyclonic eddy centers is simulated using 2-D parabolic-equation (PE) numerical modeling. It is found that the acoustic field has a significant change with variation of the location of SOFAR axis in the presence of the warm eddy and three cyclonic eddies comparing with the scenario of no eddies. When the source is located in the outside of the warm-core eddy and three cyclonic eddies respectively, and the receiver is located in outside of the eddy, the transmission loss as a function of range is investigated at different receive depth. It is shown that the changes of transmission loss caused by the warm-core eddy and three cyclonic eddies are as much as 20 dB than that of no-eddy situation. In the case of three cyclonic eddies, the largest discrepancy of transmission loss is about 40 dB near the range of 45 km for a 25-Hz source being located at a depth of 1500 m.

Irradiation damage induced on polyethylene terephtalate by 1.6 MeV deuteron ions

The irradiation damage caused on polyethylene terephtalate (Mylar, PET) samples by 1.6MeV deuteron ions has been measured using simultaneously the nuclear reaction analysis (NRA) and the transmission energy loss (TEL) techniques. The irradiation was carried out at normal incidence relative to the target surface with the irradiation beam being used as the analysis beam. The evolution of the overall damage during irradiation was evaluated by measuring the variation of the energy loss of the deuteron beam passing through the target. For this purpose, a solid state Si detector placed at a forward angle of 30° relative to the incident beam direction was used. The NRA spectra recorded by a second Si detector located backward at 150° allowed the evaluation of the carbon and the oxygen depletion. The beam spot size was circular in shape and 1mm in diameter and the beam current was set at 5nA. The ion fluence was increased up to the value of 2.5×1016deuterons/cm2. It was observed that the target energy loss decreased steadily as the fluence increased and levelled off at high fluence. The 16O(d,p0)17O, 16O(d,p1)17O∗ and 12C(d,p0)13C reactions were used for monitoring the evolution of the oxygen and carbon content as a function of the deuteron fluence. A monotonic decrease of the oxygen content with the increase of ion fluence was observed. At the highest fluence the oxygen depletion reached a value of about 75%. For carbon, a weak depletion was observed at fluence ranging from 2.5×1015d/cm2 to 1.0×1016d/cm2 followed by a levelling-off with a total loss around 20%.

The Munich ion microprobe: Characteristics and prospect

The newly developed ion microprobe SNAKE (superconducting nanoscope for applied nuclear (Kern-) physics experiments) has gone into routine operation at the Munich 14 MV tandem accelerator. It focuses ion beams, from protons to uranium, with energies that are about 10 times larger than they are available at standard nuclear microprobes. Lateral resolutions of Δ x=1.6 μm and Δ y=1.2 μm for x- and y-direction at full aperture and as low as Δ x=600 nm and Δ y=150 nm for a pencil beam have been achieved so far. The latter values are limited by positional drifts and 50 Hz oscillating fields which have become obvious in time resolved measurements. SNAKE opens new possibilities for analysis of microstructured materials as well as materials modifications. The highlights are three dimensional hydrogen analysis using proton proton scattering, high resolution transmission energy loss measurements utilizing a magnetic spectrograph and materials modification with available high energy proton and heavy ion beams. Standard techniques like particle induced X-ray emission, elastic and inelastic scattering are also used for imaging. The paper summarizes some of the prospects using the enlarged range of available ion beams and ion energies.

Gas-filled capillary discharge waveguides

We describe in detail the operation of the gas-filled capillary discharge waveguide for high-intensity laser pulses and discuss measurements and magnetohydrodynamic simulations that show that the plasma channel produced is parabolic and essentially fully ionized. We present the results of experiments in which laser pulses with a peak input intensity of 1.2×1017 W cm-2 were guided through hydrogen-filled capillary discharges with lengths of 30 and 50 mm. The pulse energy coupling and transmission losses were determined to be <4% and (7±1) m-1, respectively. We discuss the application of waveguides of this type to driving short-wavelength lasers and laser wakefield accelerators.

Performance of hemi-cylindrical and rectangular submerged breakwaters

A parametric experimental study is conducted to compare the reflection and transmission characteristics of submerged hemi-cylindrical and rectangular rigid and water-filled flexible breakwater models. The results show that, for the rigid breakwaters, rectangular models are more effective than hemi-cylindrical ones in terms of reduction of transmitted waves. As for the flexible breakwaters, the hemi-cylindrical models may give better wave reflection than rectangular ones. However, the energy loss induced by the rectangular breakwaters is much larger and more significant to result in an overall better efficiency in terms of reduction in wave transmission. The effects of internal pressure show that the lowest pressurized flexible models considered in this work are the most effective in the reduction of the transmitted wave height. Higher wave reflection, lower wave transmission and higher energy loss are obtained consistently at the lower submergence depth ratio.

Channeling energy loss of He 2+ in Si by transmission and back-scattering measurements: Experiments and computer modeling

Path-dependent electronic stopping of 3.35 MeV He 2+ ions in Si, is investigated by Rutherford back-scattering channeling in Si/SiO 2 wafers and transmission energy loss measurements in thin (1 1 0) membranes. A model which makes use of the 3-D Si electron density to calculate the stopping due to valence electrons, and the program convolution approximation for swift particles (CASP) to calculate the stopping due to core electrons, has been introduced into a Monte Carlo code for the simulation of channeling. The only adjustment allowed is the normalization to the empirical random stopping. An agreement of simulations and experiments within ±10–15% is obtained if both valence and core electron stopping components are scaled in the normalization procedure. To perform a significant comparison with the results obtained by a full atomic (CASP) model, we have also used a different normalization scheme, keeping the core component fixed and scaling only the valence electron contribution. In this case the results of the solid model, although slightly less accurate, become very similar to those obtained with the free-atom model.

Surface-penetrating flexible membrane wave barriers of finite draft

The performance of surface-penetrating flexible membrane wave barriers of finite draft is studied. The interactions of a single membrane and dual membrane systems are examined with various system parameters. The analytical solutions are derived using eigenfunction expansions assuming linear wave theory and small membrane response. Wave transmission is determined for various combinations of membrane draft, protrusion above the water surface, membrane tension and membrane spacing. The numerical solutions are compared with data obtained from experiments conducted. Comparisons of transmission coefficient and energy loss show good agreement with suitably chosen parameters of viscous losses.

Optical constants of CN x thin films from reflection electron energy loss spectroscopy

Electron energy loss spectroscopy (EELS), in both transmission (TEELS) and reflection (REELS) geometries, can provide a powerful tool to obtain the complex dielectric constant of a material over a very wide energy range. The procedures used are generally complicated having to deconvolve the experimental spectra from a number of different contributions in order to extract the bulk term which is proportional to Im(−1/ ε ̃ ). In this work we have adopted a simplified method to analyse REELS data under the assumption of a weak surface contribution to the plasmon losses due to the large mean free path for inelastic scattering of the investigated samples. The so deduced dielectric constant is presented, up to 50 eV, for some a-CN x , thin films deposited by pulsed laser ablation of graphite targets in a controlled nitrogen atmosphere. The results are compared with the experimental data obtained by conventional optical reflectivity and also with those obtained from pure amorphous carbon.

Lasers in dense gases pumped by low-energy electron beams

The use of low-energy (≈15 keV) electron beams for pumping laser systems in dense gases with high specific power deposition is described. Thin (300 nm) SiNx ceramic foils used as entrance window in a transverse geometry for the electron beam allows pressure differentials of several atmospheres with low percentage energy loss in transmission. The 1.73 μm XeI (5d[3/2]1–6p[5/2]2) infrared laser was used for a first demonstration of this concept. The laser operated between 130 and 650 mbar. A threshold pumping power of 5.3 W and a maximum output power of 6 mW were observed. The system can be scaled to high pumping power (≈MW/cm3) and short wavelength.

The experimental results on the actual measurement of energy transmission loss of magnetic field component across the tunnel

Since 1980, we have detected impulsive noise bursts of seismogenic emissions at 82 kHz, 1525 and 36 Hz with a multipoint detection network around Tokyo region. This system has recorded EM signals prior to several earthquake events and two volcanic eruptions at Mt. Mihara, 1986 and at Mt. Unzen, 1991. By our statistical analysis of these emission characteristics using the last 29 events over the last decade, impulsive magnetic energy generated with rock crash at focus area is carried along the magnetic flux from focus to epicenter, and this magnetic intensity variation seems to be induced the electromagnetic waves at the ground surface. The results of our underground measurement in the tunnel support above explanation.