Stress Relaxation Behavior of Catheter Reinforced with Braid under Combined Loading for Bending and Torsion

2013 ◽  
Vol 372 ◽  
pp. 261-264 ◽  
Author(s):  
Yasuyuki Kato ◽  
Masahito Ueda
Keyword(s):  
Stress Relaxation ◽  
Principal Axis ◽  
Physical Property ◽  
Combined Loading ◽  
Two Stage ◽  
Relative Angle ◽  
Coefficient Of Viscosity ◽  
Relationship Of ◽  
The Relationship ◽  
Step Strain

The purpose of this research is to examine the physical property of the catheter, which made of soft nylon resin and is reinforced with thin stainless wires called braid. The effect of braid on the mechanical property of the catheter is revealed by investigating the relationship of the stress relaxation and the relative angle between the braid and the principal axis of stress under combined loading of bending and torsion. Inthe first place, in order to investigate the phenomenon of stress relaxation under combined loading, the experiments under single stage step strain have been carried out by changing the ratio of bending and torsion, and the relation between the coefficient of viscosity and the relative angle of the braid is revealed. In the second place, the experiment under two-stage step strain are conducted by changing the order of bending and torsion, and the effect of these loading histories on the visco-elastic properties is examined. Moreover, the numerical simulation under two-stage step strain is carried out by using the estimated coefficient of viscosity, and in this paper, the validity of this analytical model is confirmed by comparing with the experimental results.

Visco-Elastic Properties of Catheter Reinforced with Braids: Stress Relaxation under Two-Stage Step Strain for Different Deformation Paths

2012 ◽  
Vol 622-623 ◽  
pp. 1330-1334 ◽  
Author(s):  
Yasuyuki Kato ◽  
Show Krosawa ◽  
Masahito Ueda
Keyword(s):  
Stress Relaxation ◽  
Vascular Wall ◽  
Combined Loading ◽  
Two Stage ◽  
Relative Angle ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Step Strain ◽  
Surgical Operations

Generally, as for the material of catheter, a soft characteristic is necessary so as not to damage vascular wall etc. On the other hand, responsivity and enough rigidity are required for the surgical operations such as myocardial infarction or cerebral infarction. Therefore, the catheter, which is made of soft nylon resin and is reinforced with thin stainless wires so called “braid”, is chosen as the subject of this study. The purpose of this study is to reveal the effect of braid on the mechanical property of the catheter by investigating the relationship of the stress relaxation and the relative angle between the braid and the principal axis of stress. Especially, in order to investigate the stress relaxation under combined loading, the experiments of two-stage step strain for tension and torsion are carried out with different deformation paths. Consequentially, the phenomenon of the stress relaxation reduces with the relative angle becomes smaller. Moreover, the numerical model under two-stage step strain is proposed in this paper, and the validity of this model is confirmed by comparing the calculated results with the experimental results.

scholarly journals The influence of soil compaction in explaining spatial heterogeneity of different larch forest types: a preliminary study

2019 ◽  
Vol 31 (6) ◽  
pp. 2395-2401
Author(s):  
Yuan Tian ◽  
Qiuliang Zhang ◽  
Xuan Liu
Keyword(s):  
Soil Compaction ◽  
Forest Type ◽  
Soil Depth ◽  
Physical Property ◽  
Larix Gmelinii ◽  
Forest Types ◽  
Swamp Forest ◽  
Forest Distribution ◽  
Relationship Of ◽  
The Relationship

Abstract Compacted soil has an adverse effect on plant roots and affects water and nutrient availability. However, different degrees of soil compaction may be suitable for growth and development of different understory species. This study determined whether soil compaction could explain characteristics of 10 different Dahurian larch (Larix gmelinii Rupr.) forest types in the Daxing’anling area. The relationship of soil compaction to soil depth was also studied. Forty-five tests were conducted on soil compaction of the 10 forest types with multiple comparisons, of which five showed no significant differences. At different soil depths, there were significant differences in soil compaction among forest types. The correlation between the degree of soil compaction and depth was positive and significant. The Larix gmelinii—shrub forest type, L. gmelinii—herb forest type, and L. gmelinii—swamp forest type were significantly different in soil compaction according to soil depth. This research indicates that, as a physical property, soil compaction may be used to explain forest distribution spatial variabilities.

Bilateral Shear Strength of Rectangular Frame Column with Different Stirrup on Two Principal Axis

2010 ◽  
Vol 163-167 ◽  
pp. 1728-1731
Author(s):  
Chun Min Dong ◽  
Lian Jin ◽  
Sun Jia
Keyword(s):  
Shear Strength ◽  
Concrete Structure ◽  
Principal Axis ◽  
Reinforced Concrete Structure ◽  
Rectangular Frame ◽  
Truss Model ◽  
Principal Axes ◽  
Strength Formula ◽  
Relationship Of ◽  
The Relationship

To study bilateral shear strength of rectangular frame column (RFC) with different stirrup area on two principal axis, 12 rectangular frame columns including 5 columns without stirrup and 7 columns with stirrup were tested. The analytical results indicated that the relationship of shear strength between two principal axes of RFC without stirrup could be approximately described as ellipse, and stirrup stress on two principal axes is independent. The oblique shear strength is less than the resultant force calculated by unilateral shear strength formula offered by Code for Design of Reinforced Concrete Structure. The reason for this is shear strength contributed by concrete is considered iteratively on two axes. Based on truss model and the above conclusion, a reduced coefficient is introduced to calculate the bilateral shear strength offered by concrete and the axial force, and then a formula is proposed to calculate bilateral shear strength of RFC with different stirrup area on two principal axes. Comparison between the calculation and experimental results shows the formula is feasible and safe.

The rheology of some interfacial adsorbed films of macromolecules II. Stress relaxation phenomena

1963 ◽  
Vol 271 (1346) ◽  
pp. 317-323 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Stress Relaxation ◽  
Bond Energy ◽  
Relaxation Phenomena ◽  
Water Interface ◽  
Hydrogen Bond Energy ◽  
Relaxation Spectra ◽  
Adsorbed Films ◽  
Relationship Of ◽  
The Relationship

With the use of a surface rheometer especially designed for the purpose, stress-relaxation phenomena have been studied in unimolecular films of bovine serum album in, pepsin, poly-a, L-lysine (d.p. 15) and sodium arabinate at the hydrocarbon/water interface. The behaviour of the films has been analyzed in terms of the constituent rheological elements and the relaxation spectra have been obtained. From the dependence of the relaxation spectra on temperature, the activation energies for the relaxation of the films have been found. The relationship of these energies to the hydrogen bond energy (which, it was shown in part I, is largely responsible for the observed visco-elasticity) has been discussed.

scholarly journals Experimental Study of the Feasibility of Air Flooding in an Ultra-Low Permeability Reservoir

2016 ◽  
Author(s):  
Guohui Qu ◽  
Yuanlin Meng ◽  
Anqi Shen ◽  
Yuxin Guo ◽  
Yikun Liu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Oil Recovery ◽  
Physical Property ◽  
Water Flooding ◽  
Low Permeability ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Low Permeability Reservoir ◽  
Relationship Of ◽  
The Relationship

The development effect of water flooding in ultra-low permeability reservoir was poor due to its poor physical property and high shale content, the experimental study of air flooding which help to complement producing energy was carried out. Based on the Accelerating Rate Calorimeter experimental results, the crude oil of N block in L oilfield can produce low-temperature oxidation reaction, which was the basic condition of air flooding. Three groups of experiment natural cylinder core were designed for oil displacement, water flooding and air flooding were used respectively, and the relationship of differential pressure, oil recovery, injection capacity with injection volume was investigated. It has been showed on the result that the recovery efficiency improved sharply than water flooding, the effect of depressurization and augmented injection was obvious, and the air displacement was validation.

Influence Of High Molecular Weight Factor VIII On The Expression Of Factor VIII Procoagulant Activity

1981 ◽  
Author(s):  
W Muntean ◽  
W E Hathaway ◽  
R R Montgomery
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
High Molecular Weight ◽  
Procoagulant Activity ◽  
Two Stage ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
The One ◽  
Relationship Of ◽  
The Relationship

The relationship of the high molecular weight (HMW) moiety and low molecular weight (LMW) moiety of factor VIII in expressing procoagulant activity (VIII C) was studied. LMW VIII C was prepared by immunoadsorbent chromatography; HMW VIII was prepared by chromatographing hemophilic cryo- precipitate in 4% agarose. The LMW VIII C obtained by immunoadsorbent chromatography gave higher VIII C values when tested in the one stage partial thromboplastin time (PTT) system using von Willebrand’s disease plasma as substrate than using hemophilic plasma as substrate. This finding was shown to be due to the VIII related antigen (VIIIR:Ag) in the substrate plasmas. When the VIIIR:Ag was removed from the hemophilic substrate plasma by immuno-adsorption, the VIII C values obtained for the LMW VIII C were higher. Also, adding purified HMW VIII to the von Willebrand’s disease substrate plasma resulted in lower VIII C values for the LMW VIII C in the PTT system.When the LMW VIII C was tested in the two stage assay, all VIII C was adsorbed to A1(0H)3. The adsorption of the LMW VIII C was prevented by mixing it with hemophilic plasma. From normal undiluted plasma only 5-21% of VIII C and no VIII related antigen were adsorbed to A1(OH)3, but after activation of the factor VIII of normal plasma by small amounts of thrombin, most of the VIII C was adsorbed. No VIII related antigen was adsorbed after activation.Nevertheless, when unadsorbed LMW VIII C was assayed by the two stage method both with and without HMW VIII or VIIIR:Ag, the results were the same.Our studies suggest that VIIIR:Ag prevents to some extent the activation of LMW VIII C. LMW VIII C that is not bound or protected by VIIIRiAg is adsorbed from plasma by A1(0H)3. These findings may help explain the differences for VIII C found in some patients and certain clinical circumstances with the one and two stage assays.

scholarly journals Numerical Simulation and Experiment of Hydraulic Loss of Two-Stage Flap Valves

2021 ◽  
Author(s):  
Bingnan Zhou ◽  
Weigang Lu ◽  
Bo Xu ◽  
Hua Chen
Keyword(s):  
Numerical Simulation ◽  
Opening Angle ◽  
Hydraulic Loss ◽  
Two Stage ◽  
Pump Station ◽  
Simulation And Experiment ◽  
Large Opening ◽  
Relationship Of ◽  
The Relationship ◽  
Flap Valve

As a type of flap valve evolved from integral flap valve, two-stage flap valve has the advantages of large opening angle, small hydraulic loss and small impact force on the flap valve seat when the flap valve is closed. In order to analyze and study the hydraulic loss characteristics of the two-stage flap valve, this paper takes a pump station as an example. Based on theoretical analysis, combined with numerical simulation and model test, the hydraulic loss of two-stage flap valve is studied, and the relationship between hydraulic loss and pump station flow is obtained. According to the test results, the hydraulic loss of two-stage flap valve increases with the increase of flow rate under the same opening angle of flap valve. Under the same flow condition, the larger the opening angle of the flap valve is, the smaller the hydraulic loss of the two-stage flap valve is. When the opening angle of the upper flap valve is greater than 46° and the opening angle of the lower flap valve is greater than 64°, the hydraulic loss is less than 70mm and tends to be stable. The influence of hydraulic loss on the performance of pump device is gradually weakened. The relationship between hydraulic loss and flow of two-stage flap valve no longer satisfies the relationship of square under the constant opening angle. Moreover, the larger the opening angle of the two-stage flap valve is, the greater the relationship between hydraulic loss and flow is. Compared with the integral flap valve, the two-stage flap valve has better structural form and hydraulic characteristics, and has little influence on the performance of the pump device, which can provide reference for the application of the two-stage flap valve in the pump station.

The relationship of acid-soluble glycogen to yeast flocculation

1975 ◽  
Vol 21 (10) ◽  
pp. 1608-1613 ◽  
Author(s):  
G. B. Patel ◽  
W. M. Ingledew
Keyword(s):  
Carbohydrate Metabolism ◽  
Physical Property ◽  
Glycogen Storage ◽  
Normal Strain ◽  
Saccharomyces Carlsbergensis ◽  
Yeast Flocculation ◽  
Physiological Differences ◽  
Relationship Of ◽  
The Relationship ◽  
Intracellular Acid

A relationship between yeast flocculation and intracellular acid-soluble glycogen has been established which has been substantiated using flocculation mutants (mutants with altered capacities to flocculate) as well as a normal strain of Saccharomyces carlsbergensis. Sound evidence exists to implicate physiological differences in carbohydrate metabolism (glycogen storage) to this physical property of brewing significance.

Sign in / Sign up

Export Citation Format

Share Document