An Experimental Study of the Dynamic Behavior of Foil Bearings

1972 ◽  
Vol 94 (1) ◽  
pp. 93-100
Author(s):  
T. Barnum ◽  
H. G. Elrod
Keyword(s):  
Experimental Study ◽  
Decay Rate ◽  
Dynamic Behavior ◽  
Standing Waves ◽  
The Other ◽  
Rotating Drum ◽  
Foil Bearings ◽  
Capacitance Probe ◽  
The Waves

This paper describes an experiment performed to verify the theory for the response of an infinitely wide, perfectly flexible foil to small sinusoidal variations in its tension, as developed in reference [3]. A fixed foil with a rotating drum was used. The tension was oscillated by varying the pressure in a loop of foil at one end with a fixed support at the other. The height of the foil from the drum was measured with a capacitance probe. The results agree substantially with reference [3] especially as to frequency and decay rate of the waves in the foil. However, the theory does not consider the effects of standing waves which can occur in the sections of foil between the supports and drum.

Experimental Study on the Influence of Certain Parameters over Vehicle’s Dynamic Behavior

2014 ◽  
Vol 659 ◽  
pp. 145-150
Author(s):  
George Bivol ◽  
George Ene ◽  
Marian Eduard Radulescu ◽  
Mihai Iacob ◽  
Ion Copae
Keyword(s):  
Experimental Study ◽  
Dynamic Behavior ◽  
Fuel Efficiency ◽  
The Other ◽  
Vehicle Dynamic ◽  
Functional Parameters ◽  
Dynamic Performances

Tougher request that are being formulated again and again regarding a vehicle’s dynamic performances and its fuel efficiency require a deeper study over the influence of various parameters over to the vehicle dynamic behavior. In the specialty literature we find appreciations both quantitative and qualitative regarding the influence of certain functional parameters, and how their adjustments have an impact on to the vehicle’s performances. We have to mention that the literature guides its self when analyzing the influence of certain parameters after a very restrictive methodology: when studying how a parameter influences a certain behavior all the other parameters are considered to be constant, which obviously does not happen in reality.

On the Interaction of Water Waves With a Surface-Parallel Vortex

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Amy Warncke Lang ◽  
William D. Thacker
Keyword(s):  
Experimental Study ◽  
Water Waves ◽  
Vortex Flow ◽  
Side Surface ◽  
The Other ◽  
Vortex Strength ◽  
Surface Deformations ◽  
Flow Surface ◽  
The Waves

An experimental study was performed to investigate the interaction of water waves with a surface-parallel oriented vortex at a free surface. Shadowgraph images were obtained visualizing surface deformations. The role of vortex strength and the direction of approach of the waves were investigated. For favorable waves, with flow velocity at crests parallel to vortex flow, surface deformations were weaker, lasted longer than for a vortex without waves, and were characterized at late times by the appearance of surface-normal vortices. For unfavorable waves incident on the vortex from the other side, surface deformations were stronger and dissipated more quickly.

scholarly journals Investigations on Arthropods Associated with Decay Stages of Buried Animals in Italy

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 311
Author(s):  
Teresa Bonacci ◽  
Federica Mendicino ◽  
Domenico Bonelli ◽  
Francesco Carlomagno ◽  
Giuseppe Curia ◽  
...  
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Decay Rate ◽  
Southern Italy ◽  
The Other ◽  
Post Mortem ◽  
Post Mortem Interval ◽  
Arthropod Fauna ◽  
Pig Carcasses ◽  
Deep Pits

Burial could be used by criminals to conceal the bodies of victims, interfering with the succession of sarcosaprophagous fauna and with the evaluation of post-mortem interval. In Italy, no experimental investigation on arthropods associated with buried remains has been conducted to date. A first experimental study on arthropods associated with buried carcasses was carried out in a rural area of Arcavacata di Rende (Cosenza), Southern Italy, from November 2017 to May 2018. Six pig carcasses (Susscrofa Linnaeus) were used, five of which were buried in 60-cm deep pits, leaving about 25-cm of soil above each carcass, and one was left above ground. One of the buried carcasses was periodically exhumed to evaluate the effects of disturbance on decay processes and on arthropod fauna. The other four carcasses were exhumed only once, respectively after 43, 82, 133, and 171 days. As expected, the decay rate was different among carcasses. Differences in taxa and colonization of arthropod fauna were also detected in the above ground and periodically exhumed carcasses. In carcasses exhumed only once, no arthropod colonization was detected. The results showed that a burial at about 25 cm depth could be sufficient to prevent colonization by sarcosaprophagous taxa and these data could be relevant in forensic cases involving buried corpses.

Experimental Research on Damages Detection of Pipeline Structure by Using PZT-Based Waves

2011 ◽  
Author(s):  
Shi Yan ◽  
Binbin He ◽  
Naizhi Zhao
Keyword(s):  
Damage Detection ◽  
Lead Zirconate Titanate ◽  
Smart Materials ◽  
Arrival Time ◽  
Mode Conversion ◽  
Guided Wave ◽  
The Other ◽  
Damage Location ◽  
The Waves ◽  
Peak Value

Pipeline structure may generate damages during its service life due to the influence of environment or accidental loading. The damages need to be detected and repaired if they are severe enough to influence the transportation work. Non-destructive detection using smart materials combined with suitable diagonal algorithms are widely used in the field of structural health monitoring (SHM). Piezoelectric ceramics (such as Lead Zirconate Titanate, PZT) is one of the smart materials to be applied in the SHM due to the piezoelectric effect. So far, the PZT-based wave method is widely used for damage detection of structures, in particular, pipeline structures. A series of piezoelectric patches are bonded on the surface of the pipeline structure to monitor the damages such as local crack or effective area reduction due to corrosion by using diagonal waves. The damage of the pipeline structure can be detected by analysis of the received diagonal waves which peak value, phase, and arriving time can be deferent from the health ones. The response of the diagonal wave is not only correlated to the damage location through estimation of the arrival time of the wave peak, but also associated with the peak value of the wave for the reduction of wave energy as the guided wave passing through the damages. Therefore, the presence of damages in the pipeline structure can be detected by investigating the parameter change of the guided waves. The change of the wave parameters represents the attenuation, deflection and mode conversion of the waves due to the damages. In addition, the guided wave has the ability of quick detecting the damage of the pipeline structure and the simplicity of generating and receiving detection waves by using PZT patches. To verify the proposed method, an experiment is designed and tested by using a steel pipe bonded the PZT patches on the surface of it. The PZT patches consist of an array to estimate the location and level of the damage which is simulated by an artificial notch on the surface of the structure. The several locations and deep heights of the notches are considered during the test. A pair of the PZT patches are used at the same time as one is used as an actuator and the other as a sensor, respectively. A tone burst of 5 cycles of wave shape is used during the experiment. A wave generator is applied to create the proposed waves, and the waves are amplified by an amplifier to actuate the PZT patch to emit the diagonal waves with appropriately enough energy. Meanwhile, the other PZT patch is used as a sensor to receive the diagonal signals which contain the information of the damages for processing. For data processing, an index of root mean square deviation (RMSD) of the received data is used to estimate the damage level by compare of the data between the damaged and the health peak valves of the received signals. The time reversal method which aimed at increasing the efficiency of the detection is also used to detect the damage location by estimating the arrival time of the reflected wave passing with a certain velocity. The proposed method experimentally validates that it is effective for application in damage detection of pipeline structure.

Effectiveness of Virtual Resilience Training on Assertiveness in Student Girls Aged 9–10 Years: A 1-Month Follow-Up

2021 ◽  
pp. 105984052110135
Author(s):  
Shima Gadari ◽  
Jamile Farokhzadian ◽  
Parvin Mangolian Shahrbabaki
Keyword(s):  
Experimental Study ◽  
Internal Stress ◽  
Intervention Group ◽  
The Other ◽  
Hormonal Changes ◽  
Emotional Instability ◽  
Other Hand ◽  
Significant Difference ◽  
Resilience Training

Girls between the ages of 9 and 10 begin to experience physical, physiological, and hormonal changes that may lead to internal stress. At this age, children are struggling for autonomy; on the other hand, they may experience emotional instability, and for these reasons, they may be vulnerable in many ways. This experimental study aimed to investigate the effect of resilience training on assertiveness in student girls aged 9–10. Data were collected before, immediately after, and 1 month after the intervention in the control ( n = 40) and intervention ( n = 37) groups. There was a significant difference between the assertiveness of the intervention immediately (26.80 ± 3.73) and 1 month after the intervention (27.05 ± 3.73), and assertiveness significantly increased in the intervention group ( p = .0001). Resilience training leads to improvements in assertiveness in student girls aged 9–10.

scholarly journals The Radiative Δ(1600) → γN Decay in the Light-Cone QCD Sum Rules

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 255
Author(s):  
Haifa I. Alrebdi ◽  
Thabit Barakat
Keyword(s):  
Decay Rate ◽  
Light Cone ◽  
Magnetic Dipole Moment ◽  
Sum Rules ◽  
Electric Quadrupole ◽  
The Other ◽  
Electric Quadrupole Moment ◽  
Multipole Moments ◽  
Qcd Sum Rules ◽  
Strongly Agree

Within the framework of the light-cone QCD sum rules method (LCSR’s), the radiative Δ(1600)→γN decay is studied. In particular, the magnetic dipole moment GM1(0) and the electric quadrupole moment GE1(0) are estimated. We also calculate the ratio REM=−GE1(0)GM1(0) and the decay rate. The predicted multipole moments and the decay rate strongly agree with the existing experimental results as well as with the other available phenomenological approaches.

Experimental study on dynamic behavior of woven carbon fabric laminates using in-house piezoelectric sensors

2019 ◽  
Vol 28 (10) ◽  
pp. 105004 ◽  
Author(s):  
Hafiz Qasim Ali ◽  
Isa Emami Tabrizi ◽  
Raja Muhammad Awais Khan ◽  
Jamal Seyyed Monfared Zanjani ◽  
Cagatay Yilmaz ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dynamic Behavior ◽  
Piezoelectric Sensors ◽  
Carbon Fabric

Study of wave attenuation in concrete

1993 ◽  
Vol 8 (9) ◽  
pp. 2344-2353 ◽  
Author(s):  
J-M. Berthelot ◽  
Souda M. Ben ◽  
J.L. Robert
Keyword(s):  
Experimental Study ◽  
Plane Wave ◽  
Wave Attenuation ◽  
Plane Waves ◽  
Propagation Distance ◽  
Experimental Results ◽  
The Other ◽  
Wave Frequency ◽  
Concrete Composition ◽  
Analytical Expression

The experimental study of wave attenuation in concrete has been achieved in the case of the propagation of plane waves in concrete rods. Different mortars and concretes have been investigated. A transmitter transducer coupled to one of the ends of the concrete rod generates the propagation of a plane wave in the rod. The receiver transducer, similar to the previous one, is coupled to the other end of the rod. The experimental results lead to an analytical expression for wave attenuation as function of the concrete composition, the propagation distance, and the wave frequency.

Experimental Study on Racetrack-Shaped Holes Impingement Cooling With Bump Type Roughening Element

2012 ◽  
Author(s):  
Chiyuki Nakamata ◽  
Yoji Okita ◽  
Takashi Yamane ◽  
Yoshitaka Fukuyama ◽  
Toyoaki Yoshida
Keyword(s):  
Experimental Study ◽  
Flow Condition ◽  
Reynolds Numbers ◽  
Main Flow ◽  
The Other ◽  
Relative Location ◽  
Target Plate ◽  
Cooling Effectiveness ◽  
Impingement Cooling ◽  
Cooling Air

Cooling effectiveness of an impingement cooling with array of racetrack-shaped impingement holes is investigated. Two types of specimens are investigated. One is a plain target plate and the other is a plate roughened with bump type elements. Sensitivity of relative location of bump to impingement hole on the cooling effectiveness is also investigated. Experiments are conducted under three different mainflow Reynolds numbers ranging from 2.6×105 to 4.7×105, with four different cooling air Reynolds numbers for each main flow condition. The cooling air Reynolds numbers are in the range from 1.2×103 to 1.3×104.

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