scholarly journals Investigations on physico-chemical properties of TSPCU nonwoven for application as prosthetic venous valve

2021 ◽  
Vol 7 (2) ◽  
pp. 613-616
Author(s):  
Julia Schubert ◽  
Daniela Arbeiter ◽  
Andreas Götz ◽  
Kerstin Lebahn ◽  
Wolfram Schmidt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Properties ◽  
Storage Conditions ◽  
Valve Leaflet ◽  
Venous Valve ◽  
Sem Images ◽  
Venous Valves ◽  
Prosthetic Valves ◽  
Physico Chemical ◽  
3D Printed

Abstract Electrospinning is used for producing nonwovens for medical polymer-based implants, such as prosthetic valves or covered scaffolds. In this study, nonwovens for prosthetic venous valves are investigated regarding their morphology and mechanics in physiological medium. Spinning molds were developed based on previous venous valve leaflet designs, 3D printed in different sizes and covered with electrospun nonwovens. Samples were stored in a physiological 0.9% saline at 37°C to investigate the influence of fiber rearrangement and swelling in medium for several weeks. Two different nonwovens of thermoplastic silicone-based polycarbonaturethane (TSPCU) were compared. Tensile test results show that storage in medium has a relevant influence on the mechanical properties. SEM images of TSPCU show substantially increased fiber diameters after 8 days stored in medium. After detaching the valve leaflet nonwovens from the molds, shrinkage of the material of approximately 12% was detected. A suitable valve size could be identified for joining with the stent structure into an interventional prosthetic venous valve. The results demonstrate the influence of storage conditions on the morphological and mechanical properties of electrospun TSPCU nonwovens. For development and dimensioning of venous valve leaflets, this change in mechanical behavior and possible shrinkage of the material has to be considered.

scholarly journals Mechanical Properties of U-Cu Intermetallic Compound Measured by Nanoindentation

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2215 ◽  
Author(s):  
Ruiwen Li ◽  
Chuan Mo ◽  
Yichuan Liao
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compound ◽  
Chemical Properties ◽  
Element Distribution ◽  
Treatment Temperature ◽  
Diffusion Method ◽  
Vacuum Furnace ◽  
Young’S Moduli ◽  
Pressure Diffusion ◽  
Physico Chemical

The physico-chemical properties of the Uranium intermetallic compound are of technological importance for improvement of the safety and compatibility of nuclear engineering systems. Diffusion couple samples with U and Cu were assembled and U-Cu intermetallic compounds were fabricated at interface by hot pressure diffusion method at a treatment temperature of 350 °C to 650 °C and at a pressure of 168 MPa in a vacuum furnace. The microstructure and element distribution of the compound phase have been studied by means of SEM, EDS, and XRD. The result showed that a new phase was developed to a thickness of approximately 10 μm with a ration of U:Cu with 1:5. Mechanical properties such as elastic moduli and hardness of the compound have been studied by means of nanoindentation. The nanoindentation testing on sample indicated that hardness of Uranium intermetallic compound are higher than that of metal U and Cu. Uranium intermetallic compound and U have a Young’s moduli with 121 GPa, 160 GPa respectively. The elastic/plastic responses of U-Cu intermetallic compound and U under nanoindentation tests were also discussed in detail.

Characterization of residues and evaluation of the physico chemical properties of soybean biodiesel and biodiesel: Diesel blends in different storage conditions

2020 ◽  
Vol 151 ◽  
pp. 454-462 ◽  
Author(s):  
Leandro Fontoura Cavalheiro ◽  
Marcelo Yukio Misutsu ◽  
Rafael Cardoso Rial ◽  
Luíz Henrique Viana ◽  
Lincoln Carlos Silva Oliveira
Keyword(s):  
Chemical Properties ◽  
Storage Conditions ◽  
Physico Chemical ◽  
Soybean Biodiesel

scholarly journals Tissue Level Mechanical Properties and Extracellular Matrix Investigation of the Bovine Jugular Venous Valve Tissue

2019 ◽  
Vol 6 (2) ◽  
pp. 45 ◽  
Author(s):  
Adam A. Benson ◽  
Hsiao-Ying Shadow Huang
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Radial Direction ◽  
True Strain ◽  
Transient Global Amnesia ◽  
Tissue Level ◽  
Mechanical Tests ◽  
Circumferential Direction ◽  
Venous Valve ◽  
Venous Valves

Jugular venous valve incompetence has no long-term remedy and symptoms of transient global amnesia and/or intracranial hypertension continue to discomfort patients. During this study, we interrogate the synergy of the collagen and elastin microstructure that compose the bi-layer extracellular matrix (ECM) of the jugular venous valve. In this study, we investigate the jugular venous valve and relate it to tissue-level mechanical properties, fibril orientation and fibril composition to improve fundamental knowledge of the jugular venous valves toward the development of bioprosthetic venous valve replacements. Steps include: (1) multi loading biaxial mechanical tests; (2) isolation of the elastin microstructure; (3) imaging of the elastin microstructure; and (4) imaging of the collagen microstructure, including an experimental analysis of crimp. Results from this study show that, during a 3:1 loading ratio (circumferential direction: 900 mN and radial direction: 300 mN), elastin may have the ability to contribute to the circumferential mechanical properties at low strains, for example, shifting the inflection point toward lower strains in comparison to other loading ratios. After isolating the elastin microstructure, light microscopy revealed that the overall elastin orients in the radial direction while forming a crosslinked mesh. Collagen fibers were found undulated, aligning in parallel with neighboring fibers and orienting in the circumferential direction with an interquartile range of −10.38° to 7.58° from the circumferential axis (n = 20). Collagen crimp wavelength and amplitude was found to be 38.46 ± 8.06 µm and 4.51 ± 1.65 µm, respectively (n = 87). Analyzing collagen crimp shows that crimp permits about 12% true strain circumferentially, while straightening of the overall fibers accounts for more. To the best of the authors’ knowledge, this is the first study of the jugular venous valve linking the composition and orientation of the ECM to its mechanical properties and this study will aid in forming a structure-based constitutive model.

scholarly journals The Use of Composite Materials in 3D Printing

2020 ◽  
Vol 4 (2) ◽  
pp. 42 ◽  
Author(s):  
Ignazio Blanco
Keyword(s):  
Composite Materials ◽  
3D Printing ◽  
Rapid Prototyping ◽  
Polymer Matrix ◽  
Chemical Properties ◽  
Modified Polymer ◽  
Research Activities ◽  
Physico Chemical ◽  
3D Printed ◽  
Limited Spectrum

Nowadays, all production, from the smallest ones to large companies, and research activities are affected by the use of 3D printing technology. The major limitation, in order to cover as many fields of application as possible, is represented by the set of 3D printable materials and their limited spectrum of physico-chemical properties. To expand this spectrum and employ the 3D-printed objects in areas such as biomedical, mechanical, electronical and so on, the introduction of fibers or particles in a polymer matrix has been widely studied and applied. In this review, all those studies that proposed modified polymer presenting advantages associated with rapid prototyping are reported.

scholarly journals Graphite Modified Polylactide (PLA) for 3D Printed (FDM/FFF) Sliding Elements

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1250 ◽  
Author(s):  
Robert E. Przekop ◽  
Maciej Kujawa ◽  
Wojciech Pawlak ◽  
Marta Dobrosielska ◽  
Bogna Sztorch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Stress ◽  
Low Cost ◽  
Chemical Properties ◽  
Spare Parts ◽  
The Other ◽  
Graphite Content ◽  
Before And After ◽  
3D Printed ◽  
And Chemical Properties

With the development of 3D printing technology, there is a need to produce printable materials with improved properties, e.g., sliding properties. In this paper, the authors present the possibilities of producing composites based on biodegradable PLA with the addition of graphite. The team created composites with the following graphite weight contents: 1%, 2.5%, 5%, 7.5%, and 10%. Neat material was also subjected to testing. Tribological, mechanical, and chemical properties of the mentioned materials were examined. Measurements were also made after keeping the samples in ageing and climatic ovens. Furthermore, SEM observations of samples before and after friction tests were carried out. It was demonstrated that increasing graphite content caused a significant decrease in wear (PLA + 10% graphite had a wear rate three times lower than for a neat material). The addition of graphite did not adversely affect most of the other properties, but it ought to be noted that mechanical properties changed significantly. After conditioning in a climatic oven PLA + 10% graphite has (in comparison with neat material) 11% lower fracture stress, 47% lower impact strength, and 21% higher Young’s modulus. It can be certainly stated that the addition of graphite to PLA is a step towards obtaining a material that is low-cost and suitable for printing sliding spare parts.

Strain Energy and Behaviour of Overconsolidated Soils

1967 ◽  
Vol 4 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Elmer W Brooker
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Large Scale ◽  
Chemical Properties ◽  
Earth Pressure ◽  
Quantitative Evidence ◽  
Physico Chemical ◽  
Overconsolidated Clays ◽  
Overconsolidated Soils

Bjerrum recently presented a strain energy hypothesis which explains qualitatively the behaviour of overconsolidated clays and the phenomena of long-term slope failures in these soils. Quantitative evidence, gathered from a series of large-scale consolidation tests, is presented here which supports the strain energy hypothesis. The coefficient of earth pressure at rest was found to be a function of strain energy at a given value of OCR. It is also shown that the degree of disintegration of overconsolidated soils during a slaking test is related to strain energy. It is inferred from the results that mineralogy and the capacity of a soil to adsorb strain energy are related. The evidence suggests that certain physico-chemical properties may be quantitatively related to mechanical properties through the concept of strain energy.

scholarly journals Physico-chemical properties of common beans under natural and accelerated storage conditions

2013 ◽  
Vol 40 (3) ◽  
pp. 629-636 ◽  
Author(s):  
Silvia R. M Coelho ◽  
Sandra H Prudencio ◽  
Divair Christ ◽  
Silvio C Sampaio ◽  
Vanderleia Schoeninger
Keyword(s):  
Chemical Properties ◽  
Storage Conditions ◽  
Common Beans ◽  
Accelerated Storage ◽  
Physico Chemical

scholarly journals Development and Quality Evaluation of Ready to Serve (RTS) Beverage from Banana Pseudo Stem

2020 ◽  
pp. 32-42
Author(s):  
K. Buvaneshwari ◽  
G. Sashidevi ◽  
G. Hemalatha ◽  
R. Arunkumar
Keyword(s):  
Sensory Evaluation ◽  
Chemical Properties ◽  
Nutrient Retention ◽  
Storage Conditions ◽  
Lemon Juice ◽  
Balanced Diet ◽  
Storage Study ◽  
Standard Procedures ◽  
Physico Chemical ◽  
Significant Difference

Vegetable beverage was part of a balanced diet that make sure the vigor and healthy body. Vegetable juices were rich in fiber content which was quickly inducing the feeling of satiety and also improve digestion. The objective of this study was to formulate and prepare ready to serve (RTS) banana pseudo stem beverage. Two banana varieties were selected viz., ottu vazhai (syn Mupaddai) (V1), vayal vazhai (V2). Banana pseudo stem beverage was developed from banana tender core, natural flavorings (lemon, mint)extracts, 2% citric acid as a anti-browning agent, KMS (70ppm) as preservative and CMC (0.1%) as a stabilizer. The proximate composition, physico- chemical analysis, sensory evaluation and microbial study of the pseudo stem beverage was evaluated using standard procedures. The beverages were evaluated at 15 days interval period. During storage conditions the quality of juice with minimum significant changes in chemical properties was observed with the addition of KMS. Based on the sensory evaluation, lemon juice flavored pseudo stem beverage was highly accepted by consumer than mint flavored beverage. Storage study for the pseudo stem beverage was also carried out and significant difference was noticed in beverage. Compare to vayal vazhai (V2), the yield of juice (87.0%) content was higher in ottu vazhai (syn Mupaddai) (V1).The maximum desirable results were obtained from (V1) lemon flavored beverage stored at refrigeration condition. The results were showed that pH (3.28 to 4.75), TSS (12 to 14.0° brix), Acidity (0.35 to 0.26) and vitamin C (0.77 to 0.59). From the storage studies, the lemon flavored pseudo stem beverage (Mupaddai variety V1) was found to be the best in nutrient retention and sensory evaluation than mint flavour beverage and it was accepted up to 45 days.

scholarly journals Evolution of an alumina-magnesia/self-forming spinel castable. Part II: physico-chemical and mechanical properties

Cerâmica ◽  
1999 ◽  
Vol 45 (295) ◽  
pp. 146-149
Author(s):  
D. Gutiérrez-Campos ◽  
J. I. Diaz ◽  
R. M. Rodriguez
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Chemical Properties ◽  
Microstructural Characteristics ◽  
Crushing Strength ◽  
Physico Chemical ◽  
Cold Crushing Strength

This study was carried out in conjunction with the investigation, reported in Part I, on the microstructural characteristics of an alumina-spinel castable with several percentages of MgO content. Bulk density and cold crushing strength of samples were evaluated dried and at three fired states (1000, 1200, 1400 °C). Results indicate little influence of MgO additions on physico-chemical properties of the alumina-magnesia/self-forming spinel castable. Characteristics compared with those reported for conventional alumina-spinel castables did not show large difference in values. Therefore, the alumina-magnesia/self-forming spinel castable could be a possible material for substitution of the conventional alumina-spinel castable.

Sign in / Sign up

Export Citation Format

Share Document