scholarly journals A Study of the Suitable Measurement Location and Metrics for Assessing the Vibration Source Strength Based on the Field-Testing Data of Nanchang Underground Railway

2018 ◽  
Vol 52 (5) ◽  
pp. 22-27
Author(s):  
Ling Zhang ◽  
Xiaoyan Lei ◽  
Jian Jiang ◽  
Qingsong Feng
Keyword(s):  
Field Testing ◽  
Vibration Source ◽  
Source Strength ◽  
Strength Based ◽  
Testing Data ◽  
Underground Railway ◽  
Measurement Location

The Challenges of Wide Ranging Viscosity Fluids on Liquid Ultrasonic Flowmeters

2006 ◽  
Author(s):  
Jeffrey L. Walters
Keyword(s):  
Elevated Temperature ◽  
Temperature Effects ◽  
Flow Measurement ◽  
Field Testing ◽  
Signal Propagation ◽  
Oil Fields ◽  
Flow Profile ◽  
Fluid Temperature ◽  
Testing Data ◽  
Novel Approaches

Wide ranging viscosities in ultrasonic flow measurement for liquids is a common pipeline scenario. With ever maturing oil fields and the growth in oilsands production, the trend appears to be towards the higher end viscosities and/or novel approaches towards reducing the viscosities for transportation such as heating. The variable viscosities of the fluids provide some unique challenges to ultrasonic flowmeters not only in terms of flow profile modeling, but also in acoustic signal propagation and application to elevated temperature fluids which likewise affect the accuracy or performance of the measurement. The flow profile interrogation techniques will be discussed with an emphasis on a distributed chord model together with the use of a waveguide technology that minimizes acoustic and fluid temperature effects. A combination of R&D, calibration and field testing data will both demonstrate these challenges as well as show the increased performance that results from the application of these approaches.

Estimating concrete strength using field testing data

2014 ◽  
pp. 524-529
Author(s):  
A Colombo ◽  
L Meneghetti ◽  
R Teixeira ◽  
T Bittencourt
Keyword(s):  
Concrete Strength ◽  
Field Testing ◽  
Testing Data

Field testing of ICHD-3 beta criteria of periictal headaches in patients with focal epilepsy – a prospective diary study

Cephalalgia ◽  
2016 ◽  
Vol 38 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Doris Lieba-Samal ◽  
Christian Wöber ◽  
Christoph Waiß ◽  
Theresa Kastiunig ◽  
Matthias Seidl ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Field Testing ◽  
Daily Basis ◽  
Diary Study ◽  
Seizure Onset ◽  
Prospective Data ◽  
Single Episode ◽  
Headache Onset ◽  
Testing Data ◽  
Video Eeg

Background To date we are lacking prospective data for field testing of ICHD-3 beta criteria for periictal headache (PIH). Methods Patients with focal epilepsy diagnosed by means of prolonged video-EEG monitoring completed a paper-pencil diary for three months and recorded seizures and headaches on a daily basis. According to ICHD-3 beta, we classified PIH, defined as headache present on a day with at least one seizure, as “7.6 headache related to epileptic seizure”, “7.6.1 hemicrania epileptica” or “7.6.2 postictal headache”. In addition, we compared the ICHD-3 beta diagnoses to the diagnoses according to ICHD-2. Results Thirty two patients completed the diary. Data analysis included 2,668 patient days, 300 seizures and 37 episodes of PIH. Two of these episodes (5.4%) were classified as headache related to seizure, three (8.1%) fulfilled both the criteria of headache related to seizure and hemicrania epileptica and four (10.8%) were postictal headaches. Twenty eight episodes (75.7%) did not fulfil any of the ICHD-3 beta criteria of seizure-related headaches, mostly because headache onset was before seizure onset. Applying ICHD-2 criteria allowed only one single episode of PIH to be classified as postictal headache. Discussion Our study is the first to present prospective field testing data of the ICHD-3 beta criteria for three types of seizure-related headaches. The majority of PIH episodes do not fulfil any of these criteria. One quarter can be classified according to ICHD-3 beta, whereas purely clinical diagnosis of PIH is markedly restricted in ICHD-2 because of mandatory electroencephalographic evidence.

A pantograph arcing model for electrified railways with different speeds

2017 ◽  
Vol 232 (6) ◽  
pp. 1731-1740 ◽  
Author(s):  
Guoqiang Gao ◽  
Tingting Zhang ◽  
Wenfu Wei ◽  
Yi Hu ◽  
Guangning Wu ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Average Power ◽  
Field Tests ◽  
Field Testing ◽  
Electrical Characteristics ◽  
Zero Crossing ◽  
Crossing Time ◽  
Testing Data ◽  
Traction Power ◽  
Electrified Railways

Pantograph arcing is an unavoidable phenomenon in electrified railways, which not only causes damage to the carbon strip and the catenary contact line but also results in voltage surge and electromagnetic interference. In recent years, there are more cases of pantograph arcing due to the increase in speed of trains. Therefore, it is essential to understand the basic electrical characteristics of pantograph arcing at different running speeds of trains. In this work, a pantograph arcing model was proposed, which considers the effects of the speed of a train on the arc-dissipated power. An overall electrical model, concerning the traction power system and the traction drive system, was further established. The results indicated that the running speed of trains significantly influenced the arcing voltage, duration of arcing, and the zero-crossing time. A qualitative relation between the average power of the arc and the speed of the train was also presented. Finally, field tests were carried out, and comparisons between the field testing data and the calculated results were made, which validate the accuracy of the developed model.

scholarly journals DEVELOPMENT OF AN EXPERT SYSTEM

HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 795B-795 ◽  
Author(s):  
Janice E. McClure
Keyword(s):  
Knowledge Representation ◽  
Expert Systems ◽  
Goal Setting ◽  
Knowledge Engineering ◽  
Field Testing ◽  
Special Problem ◽  
Problem Definition ◽  
Testing Data ◽  
On Farm ◽  
Selection Of

The development of expert systems in agriculture consists of many steps such as problem definition, selection of experts, audience considerations, knowledge representation, coding, testing, and feedback. The problem definition and selection of experts for the problem domain are the foundation of a working system. Audience definition, economics and goal setting are areas that must be documented before knowledge engineering. Knowledge representation methods and system conceptual layout are the next level of development. The use of the user feedback and field testing data to improve the system are often overlooked. Benefits of expert systems for on farm decision making include education, efficiency, and adaption to changing regulations. Many aspects of agricultural expert systems are similar to traditional expert systems; yet special problem inherent in agriculture make the development interesting and challenging.

On Discontinuous Dynamics of a Freight Train Suspension System

2014 ◽  
Vol 24 (12) ◽  
pp. 1450163 ◽  
Author(s):  
Dennis O'Connor ◽  
Albert C. J. Luo
Keyword(s):  
Local Stability ◽  
Wedge Angle ◽  
Field Testing ◽  
Suspension System ◽  
Analytical Prediction ◽  
Periodic Motions ◽  
Freight Train ◽  
Suspension Systems ◽  
Testing Data ◽  
Wedge Effect

In this paper, a freight train suspension system is presented for all possible types of motion. The suspension system experiences impacts and friction between wedges and bolster. The impacts cause the chatter motions between wedges and bolster, and the friction will cause the stick and nonstick motions between wedges and bolster. Due to the wedge effect, the suspension system may become stuck and not move, which can cause the suspension to lose functions. To discuss such phenomena in the freight train suspension systems, the theory of discontinuous dynamical systems is used, and the motion mechanism of impacting chatter with stick and stuck is discussed. The analytical conditions for the onset and vanishing of stick motions between the wedges and bolster are presented, and the condition for maintaining stick motion was achieved as well. The analytical conditions are developed for the onset and vanishing conditions for stuck motion. An analytical prediction of periodic motions relative to impacting chatter with stick and stuck motions in the train suspension is performed through the mapping dynamics. The corresponding analyses of local stability and bifurcation are carried out, and the grazing and stick conditions are used to determine periodic motions. Numerical simulations illustrate periodic motions of stick and stuck motions. Finally, from field testing data, the effects of wedge angle on the motions of the suspension are presented to find a more desirable suspension response for design.

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