Evaluation method for acoustic underwater propulsion systems

2021 ◽  
Vol 150 (2) ◽  
pp. 1157-1164
Author(s):  
Deqing Kong ◽  
Yuan Qian ◽  
Minoru Kuribayashi Kurosawa ◽  
Manabu Aoyagi
Keyword(s):  
Evaluation Method ◽  
Propulsion Systems ◽  
Underwater Propulsion

Fluid Flow in the Vicinity of a Vibrating Ionic Polymer Metal Composite: Part 1—Experimental Study

2009 ◽  
Author(s):  
Sean D. Peterson ◽  
Maurizio Porfiri ◽  
Alessandro Rovardi
Keyword(s):  
Flow Field ◽  
Aqueous Environment ◽  
Metal Composite ◽  
Propulsion Systems ◽  
Ionic Polymer ◽  
Physical Experiments ◽  
Underwater Propulsion ◽  
Polymer Metal ◽  
The Mean ◽  
High Flexibility

Low power consumption and activation voltage combined with high flexibility and minimal weight make Ionic Polymer Metal Composites (IPMCs) well-suited for miniaturized underwater propulsion systems. In this series of papers, we comprehensively discuss the flow field induced by an IPMC strip vibrating in a quiescent aqueous environment by performing complementary physical experiments and numerical simulations. The experimental results are presented in this paper. Planar particle image velocimetry is used to measure the time-averaged flow field of a vibrating IPMC. The momentum transferred to the fluid is computed to estimate the mean thrust generated by the vibrating actuator. We find that the mean thrust increases with the Reynolds number, defined by the maximum tip speed and IPMC length, and is only marginally affected by the relative vibration amplitude. Detailed understanding of the flow environment induced by a vibrating IPMC can guide the optimization of IPMC-based propulsion systems for bio-mimetic robotic swimmers.

Evaluating the Probability of Power Loss in Ship Electric Propulsion Systems Based on Bayesian Belief Networks

2019 ◽  
Vol 53 (3) ◽  
pp. 63-79
Author(s):  
Wenfen Zhang ◽  
Xinping Yan ◽  
Di Zhang ◽  
Jinfen Zhang
Keyword(s):  
Power Loss ◽  
Electric Propulsion ◽  
Evaluation Method ◽  
Significant Risk ◽  
Bayesian Belief Networks ◽  
Maritime Transportation ◽  
Belief Networks ◽  
Propulsion Systems ◽  
Probability Evaluation ◽  
Main Component

AbstractThe development of smart and green ships has led to the wide use of electric propulsion systems, creating many safety problems. The ship electric propulsion system (SEPS) loses power frequently, creating significant risk in maritime transportation. This article proposed a probability evaluation method to assess SEPS power loss, based on Bayesian Belief Networks (BBNs). The BBN structure of power loss in a SEPS is considered the main component causing SEPS disruption. The prior probability and conditional probability tables of the model were generated using statistical data and expert judgment. A case study was conducted to illustrate the proposed model. Finally, a sensitivity analysis was used to identify several key indicators, including human factors, navigation conditions, winding failure, aging, and parameter setting. Compared with related research, the proposed method is rational and effective. As such, the method presented in this article provides a practical and flexible way to evaluate the probability of power loss in a SEPS. The model enables the safety manager to discover key influencing factors and components during ship operations, providing effective ways to reduce ship power loss.

Evaluation method for imaging plate resolution by means of phase contrast transfer function

1995 ◽  
Vol 53 ◽  
pp. 662-663 ◽  
Author(s):  
T. Oikawa ◽  
H. Kosugi ◽  
F. Hosokawa ◽  
D. Shindo ◽  
M. Kersker
Keyword(s):  
Transfer Function ◽  
Phase Contrast ◽  
Evaluation Method ◽  
Amorphous Film ◽  
Imaging Plate ◽  
X Rays ◽  
Special Shape ◽  
Contrast Transfer Function ◽  
Contrast Image ◽  
Specimen Shape

Evaluation of the resolution of the Imaging Plate (IP) has been attempted by some methods. An evaluation method for IP resolution, which is not influenced by hard X-rays at higher accelerating voltages, was proposed previously by the present authors. This method, however, requires truoblesome experimental preperations partly because specially synthesized hematite was used as a specimen, and partly because a special shape of the specimen was used as a standard image. In this paper, a convenient evaluation method which is not infuenced by the specimen shape and image direction, is newly proposed. In this method, phase contrast images of thin amorphous film are used.Several diffraction rings are obtained by the Fourier transformation of a phase contrast image of thin amorphous film, taken at a large under focus. The rings show the spatial-frequency spectrum corresponding to the phase contrast transfer function (PCTF). The envelope function is obtained by connecting the peak intensities of the rings. The evelope function is offten used for evaluation of the instrument, because the function shows the performance of the electron microscope (EM).

Combining Values

2002 ◽  
Vol 7 (2) ◽  
pp. 1-4, 12 ◽  
Author(s):  
Christopher R. Brigham
Keyword(s):  
Lower Extremity ◽  
Upper Extremity ◽  
Evaluation Method ◽  
Proximal Phalanx ◽  
Common Error ◽  
The Third ◽  
Whole Person ◽  
Impairment Ratings ◽  
Upper Extremity Impairment ◽  
The Individual

Abstract To account for the effects of multiple impairments, evaluating physicians must provide a summary value that combines multiple impairments so the whole person impairment is equal to or less than the sum of all the individual impairment values. A common error is to add values that should be combined and typically results in an inflated rating. The Combined Values Chart in the AMA Guides to the Evaluation of Permanent Impairment, Fifth Edition, includes instructions that guide physicians about combining impairment ratings. For example, impairment values within a region generally are combined and converted to a whole person permanent impairment before combination with the results from other regions (exceptions include certain impairments of the spine and extremities). When they combine three or more values, physicians should select and combine the two lowest values; this value is combined with the third value to yield the total value. Upper extremity impairment ratings are combined based on the principle that a second and each succeeding impairment applies not to the whole unit (eg, whole finger) but only to the part that remains (eg, proximal phalanx). Physicians who combine lower extremity impairments usually use only one evaluation method, but, if more than one method is used, the physician should use the Combined Values Chart.

A fuzzy evaluation method of road vehicle automatic weighing instrument in dynamic force metrological performance

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1365-1372
Author(s):  
Xiaohui Mao ◽  
Liping Fei ◽  
Xianping Shang ◽  
Jie Chen ◽  
Zhihao Zhao
Keyword(s):  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Dynamic Performance ◽  
Dynamic Force ◽  
Fuzzy Evaluation ◽  
Road Vehicle ◽  
Evaluation Standard ◽  
The Road ◽  
Metrological Performance

The measurement performance of road vehicle automatic weighing instrument installed on highways is directly related to the safety of roads and bridges. The fuzzy number indicates that the uncertain quantization problem has obvious advantages. By analyzing the factors affecting the metrological performance of the road vehicle automatic weighing instrument, combined with the fuzzy mathematics theory, the weight evaluation model of the dynamic performance evaluation of the road vehicle automatic weighing instrument is proposed. The factors of measurement performance are summarized and calculated, and the comprehensive evaluation standard of the metering performance of the weighing equipment is obtained, so as to realize the quantifiable analysis and evaluation of the metering performance of the dynamic road vehicle automatic weighing instrument in use, and provide data reference for adopting a more scientific measurement supervision method.

Simply supported FPEDs connected by springs for broadband energy harvesting

2020 ◽  
Vol 64 (1-4) ◽  
pp. 201-210
Author(s):  
Yoshikazu Tanaka ◽  
Satoru Odake ◽  
Jun Miyake ◽  
Hidemi Mutsuda ◽  
Atanas A. Popov ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Evaluation Method ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Functional Materials ◽  
Vibration Energy ◽  
Theoretical Evaluation ◽  
Vibration Energy Harvester ◽  
Polyvinylidene Difluoride ◽  
Simply Supported

Energy harvesting methods that use functional materials have attracted interest because they can take advantage of an abundant but underutilized energy source. Most vibration energy harvester designs operate most effectively around their resonant frequency. However, in practice, the frequency band for ambient vibrational energy is typically broad. The development of technologies for broadband energy harvesting is therefore desirable. The authors previously proposed an energy harvester, called a flexible piezoelectric device (FPED), that consists of a piezoelectric film (polyvinylidene difluoride) and a soft material, such as silicon rubber or polyethylene terephthalate. The authors also proposed a system based on FPEDs for broadband energy harvesting. The system consisted of cantilevered FPEDs, with each FPED connected via a spring. Simply supported FPEDs also have potential for broadband energy harvesting, and here, a theoretical evaluation method is proposed for such a system. Experiments are conducted to validate the derived model.

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