scholarly journals Dynamics of Anisotropically Supported Rotors

1997 ◽  
Vol 3 (2) ◽  
pp. 133-142
Author(s):  
Agnes Muszynska ◽  
Charles T. Hatch ◽  
Donald E. Bently
Keyword(s):  
Field Data ◽  
Processing System ◽  
Major Axis ◽  
Experimental Results ◽  
Lateral Vibration ◽  
Dynamic Effects ◽  
Radial Stiffness ◽  
Data Acquistion ◽  
Different Characteristics ◽  
Rotor Model

The paper discusses dynamic effects occurring in machinery rotors supported in bearings and pedestals with laterally different characteristics. In the considered rotor model the anisotropy of radial stiffness and tangential (“cross”) stiffness components are included. Within certain ranges of the rotative speed the support anisotropy leads to the specific, excited-by-unbalance rotor lateral synchronous vibrations in a form of backward (reverse) precession. In addition, one section of the rotor may precess backward, while the other section simultaneously precesses forward. Experimental results illustrate this phenomenon. The analytical model of the system is based on multimode modal approach. It is also shown in this paper that greatly enhanced information for machine malfunction diagnostics can be obtained by simulated rotation of the XY transducer system observing rotor lateral vibration. This simulated rotation can be accomplished by the machine diagnostic data acquistion and processing system. The data processing also includes extraction of forward and backward components of elliptical orbits filtered to one frequency, and the filtered orbit major axis magnitude and its angular orientation.Numerical examples, field data, and experimental results performed on a rotor rig illustrate applications.

Review Summary Generation in Online Systems: Frameworks for Supervised and Unsupervised Scenarios

2021 ◽  
Vol 15 (3) ◽  
pp. 1-33
Author(s):  
Wenjun Jiang ◽  
Jing Chen ◽  
Xiaofei Ding ◽  
Jie Wu ◽  
Jiawei He ◽  
...  
Keyword(s):  
Decision Making ◽  
Real World ◽  
Text Summarization ◽  
Experimental Results ◽  
Product Review ◽  
Comprehensive Review ◽  
Online Systems ◽  
Real World Datasets ◽  
Different Characteristics

In online systems, including e-commerce platforms, many users resort to the reviews or comments generated by previous consumers for decision making, while their time is limited to deal with many reviews. Therefore, a review summary, which contains all important features in user-generated reviews, is expected. In this article, we study “how to generate a comprehensive review summary from a large number of user-generated reviews.” This can be implemented by text summarization, which mainly has two types of extractive and abstractive approaches. Both of these approaches can deal with both supervised and unsupervised scenarios, but the former may generate redundant and incoherent summaries, while the latter can avoid redundancy but usually can only deal with short sequences. Moreover, both approaches may neglect the sentiment information. To address the above issues, we propose comprehensive Review Summary Generation frameworks to deal with the supervised and unsupervised scenarios. We design two different preprocess models of re-ranking and selecting to identify the important sentences while keeping users’ sentiment in the original reviews. These sentences can be further used to generate review summaries with text summarization methods. Experimental results in seven real-world datasets (Idebate, Rotten Tomatoes Amazon, Yelp, and three unlabelled product review datasets in Amazon) demonstrate that our work performs well in review summary generation. Moreover, the re-ranking and selecting models show different characteristics.

Using an induction coil sensor to indirectly measure the B-field response in the bandwidth of the transient electromagnetic method

Geophysics ◽  
2000 ◽  
Vol 65 (5) ◽  
pp. 1489-1494 ◽  
Author(s):  
Richard S. Smith ◽  
A. Peter Annan
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
Indirect Measurement ◽  
Rate Of Change ◽  
Induction Coil ◽  
Voltage Response ◽  
Magnetic Field Data ◽  
Transient Electromagnetic ◽  
Different Characteristics ◽  
The Magnetic Field

The traditional sensor used in transient electromagnetic (EM) systems is an induction coil. This sensor measures a voltage response proportional to the time rate of change of the magnetic field in the EM bandwidth. By simply integrating the digitized output voltage from the induction coil, it is possible to obtain an indirect measurement of the magnetic field in the same bandwidth. The simple integration methodology is validated by showing that there is good agreement between synthetic voltage data integrated to a magnetic field and synthetic magnetic‐field data calculated directly. Further experimental work compares induction‐coil magnetic‐field data collected along a profile with data measured using a SQUID magnetometer. These two electromagnetic profiles look similar, and a comparison of the decay curves at a critical point on the profile shows that the two types of measurements agree within the bounds of experimental error. Comparison of measured voltage and magnetic‐field data show that the two sets of profiles have quite different characteristics. The magnetic‐field data is better for identifying, discriminating, and interpreting good conductors, while suppressing the less conductive targets. An induction coil is therefore a suitable sensor for the indirect collection of EM magnetic‐field data.

scholarly journals Predictive Modelling of Wellhead Corrosion due to Operating Conditions: A Field Data Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Chinedu I. Ossai
Keyword(s):  
Corrosion Rate ◽  
Field Data ◽  
Oil And Gas ◽  
Multiple Linear Regression Model ◽  
Predictive Modelling ◽  
Operating Conditions ◽  
Experimental Results ◽  
Operating Parameters ◽  
Oil And Gas Fields ◽  
The Impact

The flow of crude oil, water, and gas from the reservoirs through the wellheads results in its deterioration. This deterioration which is due to the impact of turbulence, corrosion, and erosion significantly reduces the integrity of the wellheads. Effectively managing the wellheads, therefore, requires the knowledge of the extent to which these factors contribute to its degradation. In this paper, the contribution of some operating parameters (temperature, CO2 partial pressure, flow rate, and pH) on the corrosion rate of oil and gas wellheads was studied. Field data from onshore oil and gas fields were analysed with multiple linear regression model to determine the dependency of the corrosion rate on the operating parameters. ANOVA, value test, and multiple regression coefficients were used in the statistical analysis of the results, while in previous experimental results, de Waard-Milliams models and de Waard-Lotz model were used to validate the modelled wellhead corrosion rates. The study shows that the operating parameters contribute to about 26% of the wellhead corrosion rate. The predicted corrosion models also showed a good agreement with the field data and the de Waard-Lotz models but mixed results with the experimental results and the de Waard-Milliams models.

Improvement on Curve Negotiation Performance of Suspended Monorail Vehicle Considering Flexible Guideway

2020 ◽  
Vol 20 (05) ◽  
pp. 2050057
Author(s):  
Qinglie He ◽  
Chengbiao Cai ◽  
Shengyang Zhu ◽  
Kaiyun Wang ◽  
Yongzhi Jiang ◽  
...  
Keyword(s):  
Interaction Model ◽  
Dynamic Responses ◽  
Secondary Development ◽  
Design Parameters ◽  
Lateral Vibration ◽  
Vibration Level ◽  
Radial Stiffness ◽  
Negotiation Performance ◽  
Lateral Displacements ◽  
Curve Negotiation

This work presents the investigation and improvement on curve negotiation performance of suspended monorail vehicle considering a flexible guideway. First, a spatial train–guideway interaction model of suspended monorail system (SMS) is established based on the secondary development of ANSYS software. Then, the dynamic analysis of the train over the flexible curved guideway is conducted, and the curve negotiation performance of the vehicle and the guideway vibration feature are revealed. Subsequently, several crucial design parameters that significantly influence the curve negotiation performance of the vehicle are found, and their influences on the train–guideway dynamic responses are systematically investigated. Finally, by comprehensively considering the dynamic indexes of the vehicle–guideway system, the optimal ranges of these crucial design parameters are obtained. Results show that decreasing the radial stiffness of guiding tyre can effectively reduce the lateral vibration levels of vehicle and guideway, but it would increase the lateral displacements of the bogie and hanging beam; and the radial stiffness is finally suggested to be around 1[Formula: see text]kN/mm by comprehensively considering all dynamic indexes. Increasing the initial compression displacement of guiding tyre can well limit the lateral displacements of the bogie and the hanging beam, thus enhancing the train running safety; however, it would intensify the vehicle-guideway lateral vibration level; especially, the optimal initial compression displacement of guiding tyre is related to its radial stiffness characteristics. To ensure a good curve negotiation performance of vehicle and guideway vibration level, the stiffness of the anti-roll torsion bar and the initial gradient angle of the installed trapezoid four-link suspended device are suggested to be 1.0[Formula: see text]MNm/rad and 65–[Formula: see text], respectively.

Experimental and Analytical Investigation on Spaghetti Problem

2001 ◽  
Author(s):  
Yoshimasa Komaki ◽  
Nobuyuki Kobayashi ◽  
Masahiro Watanabe
Keyword(s):  
Dynamic Behavior ◽  
Multibody Dynamics ◽  
Constant Velocity ◽  
Analytical Investigation ◽  
Experimental Results ◽  
Flexible Beam ◽  
Gap Size ◽  
Lateral Vibration ◽  
Elastic Wall ◽  
Pulling Velocity

Abstract The dynamic behavior of the flexible beam, which is pulled into the slit of the elastic wall with a constant velocity, is discussed with multibody dynamics formulation and experiments. The vibration of the free tip of a flexible beam increases rapidly as pulling into the slit, and this behavior is called “Spaghetti Problem”. The effect of gap size of the slit on the behavior of Spaghetti Problem is especially focused. Dynamic behavior of the beam is simulated numerically and examined the accuracy of the presented formulation by changing the gap size and the pulling velocity of the beam as parameters. It is clarified that the presented modeling method simulates the experimental results quite well, and the gap size and the pulling velocity influence the increase of the lateral vibration near the inlet of the slit.

The Approaches for Estimation of Grain Size in Digital Steel Microscopic Image

2012 ◽  
Vol 487 ◽  
pp. 466-470
Author(s):  
Qiu Dong Sun ◽  
Yong Ping Qiu ◽  
Wen Xin Ma ◽  
Wen Ying Yan
Keyword(s):  
Grain Size ◽  
Major Axis ◽  
Average Diameter ◽  
Minor Axis ◽  
Experimental Results ◽  
Microscopic Image ◽  
Counting Method ◽  
Average Area ◽  
Important Basis

The estimation of grain size is the important basis of metallographical analysis. The definitions of grain size, area, average area, chord, major axis, minor axis, diameter and average diameter are given in this article. A filling-and-elimination counting method is also introduced to count the number of grains in the digital steel microscopic image. The equations for calculating average area and diameter of grains are presented too. Finally, an algorithm for calculating grain’s average diameter is given. The experimental results show that the proposed approaches are efficient and practical.

Decrements in Tracking and Visual Performance during Vibration

1973 ◽  
Vol 15 (4) ◽  
pp. 379-393 ◽  
Author(s):  
Allan M. Collins
Keyword(s):  
Visual Acuity ◽  
Literature Review ◽  
Human Performance ◽  
Vertical Vibration ◽  
Experimental Results ◽  
Visual Performance ◽  
Lateral Vibration ◽  
Do So

This literature review specifies the decrements in human performance on tracking and visual acuity tasks during vibration in terms of frequency, acceleration, and direction of vibration. For z-axis (vertical) vibration, which has been studied most extensively, it has been possible to develop tentative equal-decrement curves in terms of frequency and acceleration. For x-axis (longitudinal) and y-axis (lateral) vibration, there are not enough data to do so. The effects of other variables are discussed briefly, and an hypothesis is offered for translating experimental results into predictions of performance decrements for workers in vibration environments.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Experimental System and Creation of Virtual Guiding Surfaces)

2013 ◽  
Vol 25 (2) ◽  
pp. 285-293 ◽  
Author(s):  
Mineo Higuchi ◽  
◽  
Tsukasa Ogasawara ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Experimental System ◽  
Major Axis ◽  
Experimental Results ◽  
Physical Interaction ◽  
Assist Device ◽  
Two Degrees Of Freedom ◽  
Direct Physical Interaction ◽  
Continuously Variable Transmissions

We describe a new robotic assist device: the passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator. PASArms are physically passive. The force to manipulate the arm end must be provided by the operator. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces that constrain and guide the motion of the operator. PAS-Arms have three joints and a three dimensional workspace, but possess only two degrees of freedom due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. In this paper, we first discuss the manipulability ellipsoid for the PAS-Arm. The major axis of the ellipsoid is the direction in which the arm end may be easily manipulated, and vice versa. We have developed an experimental system for the PAS-Arm. The CVTs of the experimental system may not adjust the transmission ratio to zero. Second, we describe an algorithm to address that problem. Finally, we present initial experiments that verify the PAS-Arm mechanism. The experimental results successfully produced virtual guiding surfaces.1 1. This paper is the full translation from the transactions of JSME, Series C, Vol.76, No.763, pp. 611-618, 2010.

Research on the Design of Automated Hemorheology Analyzer

2011 ◽  
Vol 130-134 ◽  
pp. 3581-3584
Author(s):  
Jun Wang ◽  
Lian Qing Zhu ◽  
Ming Li Dong
Keyword(s):  
Software Design ◽  
Whole Blood ◽  
Experimental Results ◽  
Design And Implementation ◽  
Test Speed ◽  
New Instrument ◽  
Different Characteristics ◽  
Speed And Accuracy

In order to improve the speed and accuracy of the existing product, a new automated hemorheology analyzer is designed and implementation in this paper. In the new analyzer, the whole blood and plasma with different characteristics are tested by different systems, which work in parallel and independently. The design and implementation of the new hemorheology analyzer including hardware and software design are put forward. Experimental results show that the performance of the new instrument, such as efficiency and test speed are both improved in the new instrument.

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