Vibrating-wire Force Transducers

2011 ◽  
pp. 203-226
Author(s):  
Dan Mihai Ştefănescu
Keyword(s):  
Vibrating Wire ◽  
Force Transducers

scholarly journals Calibration of Transducers and of a Coil Compression Spring Constant on the Testing Equipment Simulating the Process of a Pallet Positioning in a Rack Cell

2019 ◽  
Vol 9 (1) ◽  
pp. 631-640 ◽  
Author(s):  
Leopold Hrabovský ◽  
David Dluhoš
Keyword(s):  
Control System ◽  
Strain Gauge ◽  
Testing Equipment ◽  
Pressure Force ◽  
The Third ◽  
Force Transducers ◽  
Compression Spring ◽  
Computer Controlled ◽  
Automated Process ◽  
Principal Design

AbstractIn a parking house with KOMA TOWER computer-controlled automated parking system it happens that a control system is locked out of service after a pallet has failed to reach the required position during the shifting of pallets, loaded with cars, into rack cells.In this paper is described testing equipment designed by the Institute of Transport, Faculty of Mechanical Engineering, VŠB Technical University of Ostrava for the purpose of simulating the process of pallets shifting into the rack cells in order that the frequency of error messages from the control system during the automated process of cars positioning in rack cells in the parking house may be limited.The paper details two completed parts of the designed testing equipment which provide for the calibration of strain-gauge force transducers and for the detection of coil compressive spring compression in relation to acting pressure force.The description of the third, principal design part will be provided in the next paper, together with the experimentally measured acting forces which generate, in both horizontal and vertical directions, as a pallet brake pulley rolls along a brake haunch length.

Field Monitoring of Surrounding Rock Stress in Tunnel Construction

2012 ◽  
Vol 170-173 ◽  
pp. 1735-1739
Author(s):  
Ying Na Dong ◽  
Qiang Huang
Keyword(s):  
Spatial Effect ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Rock Stress ◽  
Vibrating Wire ◽  
Stress Variation ◽  
Stress Changes ◽  
Tunnel Diameter ◽  
Surrounding Rock Stress

The surrounding rock stress field monitor has been done in excavation by vibrating wire transducer. The field monitoring data are compared with numerical simulation results. The result shows: Vibrating wire transducer can record the stress variation of surrounding rock and support. Surrounding rock stress changes violently at every excavation step, such as lower bench excavation, the stress variation is mainly controlled by the spatial effect. When the distance from excavation face to the monitoring section is more than a tunnel diameter, the rock stress variation is mainly affected by time and it is relatively smooth and continuous.

Abstract 241: Endothelial Function is Preserved with Endoscopic Vein Harvest for Lower Extremity Bypass

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Adam R Wheeler ◽  
Daniel E Kendrick ◽  
Matthew T Allemang ◽  
Andre F Gosling ◽  
Anil Nagavalli ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Lower Extremity ◽  
Endothelial Function ◽  
Endothelial Damage ◽  
Krebs Solution ◽  
Force Transducers ◽  
Submaximal Contraction ◽  
Harvesting Techniques ◽  
Harvest Techniques ◽  
Bypass Technique

Objective: Endoscopic vein harvest for lower extremity arterial bypass technique has been questioned due to concern for endothelial damage during procurement. We sought to compare NO mediated endothelial dependent relaxation (EDR) in vein segments harvested with open surgical (OH) versus endoscopic (EH) techniques. Methods: Saphenous vein segments were harvested for lower extremity bypass. 3-4mm vein rings were mounted on force transducers. Segments were mounted in 37° oxygenated Krebs solution and maximally contracted using KCl. NE was used to achieve submaximal contraction. EDR was determined using increasing concentrations of bradykinin (BDK). Endothelial independent relaxation was confirmed using sodium nitroprusside. Two-way ANOVA was used to analyze differences between harvest techniques across BDK concentration. Student t-test was used to examine nitrite levels in each cohort. Results: Vein segments harvested from patients (n=13) led to 28 rings (11 rings; 5 patients EH v. 17;8 OH). Both cohorts achieved moderate relaxation to maximal BDK concentration, [10 -6 M]; (49.5% EH vs. 40.55%, OH, P = .270). Analysis by two way ANOVA for mean % relaxation for BDK concentration [10 -11 - 10 -6 M] showed improved EDR in EH samples compared to OH (P =.029). Mean nitrite tissue bath concentration measurements post-BDK were 279 nM (EH) v. 194 nM (OH) (P = .264). Histology and IHC confirmed intact endothelium by morphometric analysis and CD31 staining. Conclusion: Endothelial function is preserved when utilizing endoscopic harvesting techniques. The advantages of minimally invasive vein procurement for lower extremity bypass can be obtained without concern for damaging venous endothelium.

Pharmacological Characterization of Postjunctional α-Adrenoceptors in Human Nasal Mucosa

2005 ◽  
Vol 19 (5) ◽  
pp. 495-502 ◽  
Author(s):  
Michel R. Corboz ◽  
Maria A. Rivelli ◽  
Lori Varty ◽  
Jennifer Mutter ◽  
Mark Cartwright ◽  
...  
Keyword(s):  
Nasal Mucosa ◽  
Isometric Force ◽  
Ringer Solution ◽  
Predominant Role ◽  
Pharmacological Characterization ◽  
Human Nasal Mucosa ◽  
Force Transducers ◽  
Arteries And Veins

Background Functional α1- and α2-adrenoreceptor subtype pharmacology was characterized in an in vitro human nasal mucosa contractile bioassay. Methods Nasal mucosa was obtained from 49 donor patients and mucosal strips were placed in chambers filled with Krebs–Ringer solution and attached to isometric force transducers. Results Nonselective α-adrenoreceptor agonists epinephrine, norepinephrine, and oxymetazoline produced concentration-dependent contractions of isolated human nasal mucosa (pD2= 5.2, 4.9, and 6.5, respectively). The α2-adrenoreceptor agonist BHT-920 (10 μM)–induced contractions were blocked by yohimbine (0.01–1 μM) and prazosin (0.01–1 μM) inhibited the contractile response to the α1-adrenoreceptor agonist phenylephrine (10 μM). Histological analysis showed that phenylephrine and BHT-920 differentially contracted the arteries and veins of human nasal mucosa, respectively. Conclusion Our results indicate that functional α1- and α2-adrenoceptors are present and functional in human nasal mucosa. The a 2-adrenoceptors display a predominant role in contracting the veins and the α1-adrenoceptors appear to preferentially constrict the human nasal arteries.

Note on Mr Joseph O. Thompson's Results regarding Vibrating Wires

1899 ◽  
Vol 22 ◽  
pp. 598-600
Author(s):  
Dr W. Peddie
Keyword(s):  
Constant Temperature ◽  
Breaking Strength ◽  
Copper Wire ◽  
Physical Review ◽  
Logarithmic Decrement ◽  
Constant Amplitude ◽  
Vibrating Wire ◽  
Constant Quantity ◽  
The Wire ◽  
Lord Kelvin

In 1865 Lord Kelvin published the results of experiments which first made evident “a very remarkable fatigue of elasticity, according to which a wire which has been kept vibrating for several hours or days through a certain range came to rest much quicker when left to itself than when set in vibration after it has been at rest for several days and then immediately left to itself.” On the strength of Lord Kelvin's statement this elastic fatigue of metals has been regarded as a definitely ascertained fact. But, quite recently (Physical Review, March 1899), Mr Joseph O. Thompson has published a paper “On the period and logarithmic decrement of a continuously vibrating wire,” in which he states that it seems probable that “for constant temperature and constant amplitude the logarithmic decrement is constant.” This conclusion is based upon his observation that the logarithmic decrement, in the case of a copper wire, when the amplitude of vibration varied from about 185° to 175°, had the same value after it had been continuously vibrated through the average arc of 180° for fifty consecutive hours as it had at the commencement of that period. Observations upon other metals seemed to support the conclusion.Lord Kelvin also stated that fatigue caused an increase of the period of vibration. Mr Thompson finds that “no matter what metal was used, no matter whether the arc of vibration was as small as 20° or as high as 200°, no matter whether the wire was long or short, thick or thin (provided of course the breaking strength of the wire was at least twice the weight of the disc), the result was uniformly the same, namely, that when temperature and amplitude of vibration remained constant, the period of vibration was a constant quantity.”

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