scholarly journals Cardiovascular catheter stiffness – a static measurement approach

2021 ◽  
Vol 7 (2) ◽  
pp. 721-723
Author(s):  
Christoph Brandt-Wunderlich ◽  
Niels Grabow ◽  
Klaus-Peter Schmitz ◽  
Stefan Siewert ◽  
Wolfram Schmidt
Keyword(s):  
Reaction Force ◽  
Bending Stiffness ◽  
Test Results ◽  
Distal Catheter ◽  
Test Setup ◽  
Frictional Properties ◽  
Maximum Reaction ◽  
Custom Made ◽  
Quantitative Results ◽  
Measurement Approach

Abstract Catheters are widely used for therapeutic and diagnostic purposes in various medical applications. Along with frictional properties as well as the catheter profile the catheter stiffness mainly affects the deliverability and thus, the handling properties of the catheter. Within this study the bending stiffness of proximal and distal catheter samples was investigated with a custom made test setup. In particular, the influence of the catheter clamping length on the test results is discussed. Bending stiffness was calculated directly from the measured force, deflection and clamping length considering the test setup compliance. Measurements were performed three times at five positions in circumferential direction. Measured bending stiffness ranged from 629 ± 31 Nmm² to 733 ± 58 Nmm² for the proximal samples and from 30 ± 5 Nmm² to 98 ± 30 Nmm² for the distal samples, respectively. Bending stiffness varied depending on the free catheter length and the reaction force measured. The maximum reaction force decreased with increasing free catheter length leading to a higher measurement uncertainty. However, when considering the same free catheter length quantitative results were similar within the group of proximal and distal samples, respectively.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

A New Method to Measure Prandtl Number and Thermal Conductivity of Fluids

1957 ◽  
Vol 24 (1) ◽  
pp. 25-28
Author(s):  
E. R. G. Eckert ◽  
T. F. Irvine
Keyword(s):  
Thermal Conductivity ◽  
Boundary Layer ◽  
Prandtl Number ◽  
High Velocity ◽  
Atmospheric Pressure ◽  
New Method ◽  
Test Results ◽  
Test Setup ◽  
Velocity Boundary Layer ◽  
Layer Flow

Abstract A new method is described by which the Prandtl number and indirectly the thermal conductivity of fluids can be measured. The method is based on the fact that a well-established, unique relation exists between the Prandtl number and the recovery factor for laminar high-velocity boundary-layer flow. The test setup is described which has been devised for such measurements, and test results are presented for air at atmospheric pressure and temperatures between 60 and 350 F.

In-flight reconfiguration of lithium-ion cells aimed at extending flight times and range of electrically powered UAVs

2019 ◽  
Vol 7 (3) ◽  
pp. 98-111 ◽  
Author(s):  
Svetoslav Zabunov ◽  
Garo Mardirossian
Keyword(s):  
Design Methodology ◽  
Lithium Ion ◽  
Test Results ◽  
Content Type ◽  
Test Setup ◽  
Lithium Ion Cells ◽  
Battery Design ◽  
Novel Design ◽  
Battery Module

Purpose The purpose of this paper is to disclose a novel reconfiguration battery design suitable for electrically powered UAVs. Design/methodology/approach A design of a reconfigurable battery module is presented. Test setup with prototype battery module is developed and described. Test results of measurements are shown and discussed. Findings The results ascertain the benefits of implementing a reconfigurable battery in small electrically powered UAVs and specifically prove the efficiency of the proposed design. Originality/value The proposed novel design is compared to previous work while advances from the latter and the gained advantages were established.

Some Gait Characteristics of Below-Knee Amputees and Their Reflection on the Ground Reaction Forces

1986 ◽  
Vol 15 (1) ◽  
pp. 27-34 ◽  
Author(s):  
R Seliktar ◽  
J Mizrahi
Keyword(s):  
Reaction Force ◽  
Kinetic Studies ◽  
Human Locomotion ◽  
Rate Of Change ◽  
Ground Reaction Forces ◽  
Test Results ◽  
Small Perturbations ◽  
Gait Characteristics ◽  
Reaction Forces ◽  
Force Characteristics

Human locomotion studies employing cinematography and force plates have been conducted during the last five decades with the goal of producing a clinically acceptable gait evaluation technique. The bulk of information contained in the kinetic studies was the major obstacle in achieving this goal. Our aim in this work was to explore the possibility of representing some locomotor abnormalities solely by their reflection on the ground reaction force characteristics. As a first stage towards the establishment of these relationships, the gait characteristics of below-knee amputees were examined. One hundred and thirty ground force test results as obtained on twenty three below-knee amputees were analysed. Different variables such as time durations of the various phases, peak forces, impulses, rate of change of the forces, and others, were examined. The conclusions suggest that some of these variables are suitable for evaluation of gait and some, such as small perturbations superimposed on the curve, may serve as indicators of specific malfunction of the prosthetic system.

Experimental Investigation on Bending Performance of Steel-Concrete Composite Slim Beams

2020 ◽  
Vol 853 ◽  
pp. 182-186
Author(s):  
Yu Chen Jiang ◽  
Xia Min Hu ◽  
Huai Dong Yan
Keyword(s):  
Experimental Investigation ◽  
Bending Stiffness ◽  
Steel Beams ◽  
Test Results ◽  
Flexural Capacity ◽  
Relative Slip ◽  
Bending Performance ◽  
Deformation Ability ◽  
Composite Slim Beam ◽  
Considerable Deformation

In this paper, the mechanical behavior of steel-concrete composite slim beams was investigated by experiments, and the influence of sectional dimension of steel beams on the bending stiffness and flexural capacity of composite slim beams was evaluated. Test results show that good cooperative performance can be achieved in steel-concrete composite slim beams and the relative slip between steel and concrete is very small. The steel-concrete slim beam presents considerable deformation ability beyond the service stage, which indicates that the composite slim beam has good ductility. In addition, sectional dimension of steel beams is proved to have significant influence on both the bending stiffness and flexural capacity of composite slim beams.

Shoulder joint hemiarthroplasty for treatment of a severe osteochondritis dissecans lesion in a dog

2014 ◽  
Vol 27 (03) ◽  
pp. 243-248 ◽  
Author(s):  
T. Sparrow ◽  
J. Meswania ◽  
G. Blunn ◽  
N. Fitzpatrick
Keyword(s):  
Osteochondritis Dissecans ◽  
Humeral Head ◽  
Shoulder Joint ◽  
Reaction Force ◽  
Force Plate ◽  
Shoulder Hemiarthroplasty ◽  
Gradual Improvement ◽  
Custom Made ◽  
Plate Analysis ◽  
Caudal Approach

SummaryIntroduction: Partial resurfacing of the humeral head has been reported in humans to treat humeral osteochondritis dissecans. The aim is to describe a custom-made humeral resurfacing prosthesis for treatment of severe humeral head osteochondritis dissecans in a dog.Case report: A seven-month-old female entire St. Bernard dog was presented with a 10 week history of severe left thoracic limb lameness. Radiography, arthroscopy and magnetic resonance imaging confirmed an extensive osteochondritis dissecans lesion affecting the caudal, medial and central regions of the humeral head. A prosthesis designed from computed tomography (CT) images was manufactured in polished stainless steel alloy with a hydroxyapatite coated base and central finned humeral stem for cementless insertion. A standard caudal approach to the shoulder was used to place the prosthesis following reaming of the caudal humeral head.Results: Radiography and CT imaging revealed appropriate topographical placement on the humerus. Force plate analysis demonstrated initial reduction in ground reaction force at six weeks, followed by gradual improvement at three months. There was no radiographic evidence of implant loosening and the range of shoulder joint motion was comparable to the contralateral joint at three months; these findings were maintained to final follow-up at 24 months.Clinical significance: Placement of a humeral head resurfacing prosthesis was an effective technique for the management of severe osteochondritis dissecans-related shoulder lameness. To the authors’ knowledge, this is the first report of the clinical use of shoulder hemiarthroplasty in a dog.

A Quantitative Method of Expressing Flex-Cracking Results

1940 ◽  
Vol 13 (3) ◽  
pp. 694-703
Author(s):  
R. G. Newton
Keyword(s):  
Statistical Methods ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Quantitative Method ◽  
Function Analysis ◽  
Good Reason ◽  
Test Method ◽  
Research Association ◽  
Test Results ◽  
Quantitative Results

Abstract In addition to providing a means of obtaining accurate quantitative results for individual flex-cracking tests, such as the De Mattia or Du Pont tests, the application of discriminant function analysis suggests a basis for standardizing the entire test method, so that objection to the test for specification purposes is thus concerned only with the reproducibility of the results, a problem which can now be investigated with greater confidence and ease. In connection with the accuracy of the method it may be contended that much depends on the subjective attitude of the tester who grades the samples with the photographs. When half-scores were not employed, the accuracy was limited mainly by the coarseness of the scale. This suggests that the grading is objective and, although no comparison, based upon statistical methods, has been made to determine the discrepancies between operators, no circumstance has occurred to suggest that important divergencies of opinion do exist. In addition, the analysis has been repeated on a further series of fifty samples, and the values found for the scoring constants were not substantially different from those obtained in this investigation. There is thus good reason to believe that this method of assessing the results will form a valuable means of investigating the causes of variation in flex-cracking test results and of recording the conclusions from the tests. The author wishes to thank the Board of Management of the Research Association of British Rubber Manufacturers for permission to publish the results given in this paper.

An Off-Resonance Synchronous Vibration Based Method for Rotor System Damage Detections

2005 ◽  
Author(s):  
Huageng Luo ◽  
Hector Rodriguez ◽  
Darren Hallman ◽  
Dennis Corbly
Keyword(s):  
Final Section ◽  
State Of The Art ◽  
Detection System ◽  
Detection Algorithm ◽  
Integrated System ◽  
Test Results ◽  
Test Rig ◽  
Test Setup ◽  
First Order ◽  
Vibration Detection

This paper presents a methodology of detecting rotor imbalances, such as mass imbalance and crack-induced imbalance, using shaft synchronous vibrations. A vibration detection algorithm is derived based on the first order nonresonant synchronous vibration response. A detection system is integrated by using state-of-the-art commercial analysis equipment. A laboratory rotor test rig with controlled mass imbalances was used to verify the integrated system. The system is then deployed to an engine sub-assembly test setup. Four specimens were used in the subassembly test and the test results are reported in the final section.

Dynamic Response of Human Legs due to Horizontal Jump

2012 ◽  
Author(s):  
Srikanth Ravuri ◽  
Fred Barez ◽  
David Wagner ◽  
Jim Kao
Keyword(s):  
Reaction Force ◽  
Three Dimensional ◽  
Simulation Software ◽  
Leap Motion ◽  
Biomechanical Simulation ◽  
Maximum Reaction ◽  
Internal Joint ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Distal Direction

Jumping is a coordinated extension of the human body through combined strength and agility to perform a leap motion far enough for the feet to land on the ground. However, the repeated reaction forces and the resulting stresses on the ankle, knee and hip joints may cause injuries to a person. A primary mechanism of such injuries is suggested to be the acute high impact loads experienced during the landing in a horizontal jump. The goal of this study is to determine the reaction force distribution at the joints in the lower extremities during the horizontal jump. A detailed biomechanical system was constructed to calculate the reaction forces generated during the horizontal jump. The horizontal jump kinematics of a participant was measured using a three-dimensional motion capture system and the landing forces were measured using two force plates. Biomechanical simulation software was used to calculate the internal joint reaction forces at the ankle, knee, and hip. It was determined that the maximum reaction forces primarily occurred in the proximo/distal direction of the hip, 2,300 N; and ankle, 2,700 N. However, at the knee joint, the maximum reaction force was determined to be in antero/posterior direction, at 2,000 N; and proximo/distal direction, at 2,100 N, respectively.

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