Measurement of Modified Surface Properties (Micro-Creep) of Polyamide by Modern Indentation Method

2019 ◽  
Vol 952 ◽  
pp. 163-171
Author(s):  
Martin Ovsik ◽  
Michal Stanek ◽  
Adam Dockal ◽  
Miroslav Manas ◽  
Lenka Hylova
Keyword(s):  
Surface Layer ◽  
Surface Properties ◽  
Three Dimensional ◽  
Indentation Test ◽  
Beta Radiation ◽  
Product Surface ◽  
Correct Function ◽  
Modified Surface

Good quality of surface layer is an important aspect for correct function and longevity of final product. Surface layer was modified by beta radiation with differing intensity. Radiation caused creation of three dimensional spatial network, that directly leads to improvements of the tested polymer’s (PA11, PA12) surface properties. Surface properties (micro-creep) were measured by micro-indentation test on MHT3 machine. Goal of this paper is to modify the surface layer (by using several different intensities of beta radiation) in a way, that causes increase in resistance against long term stress (micro-creep) in the final product, which is an important property that ensures correct function of the product. The changes in micro-creep were compared and afterwards confirmed by the use of gel test, that showed us what percentage of the whole part was crosslinked.

Improving Surface Properties of Linear Polyethylene by Radiation Measured by Ultra-Nano Indentation Test

2019 ◽  
Vol 952 ◽  
pp. 172-179
Author(s):  
Martin Ovsik ◽  
Michal Stanek ◽  
Adam Dockal ◽  
Martin Reznicek ◽  
Lenka Hylova
Keyword(s):  
Mechanical Properties ◽  
Surface Properties ◽  
Three Dimensional ◽  
Indentation Test ◽  
Optimal Dose ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Deformation Work ◽  
Correct Function ◽  
Economical Aspect

Surface properties are important aspect for correct function of construction (technical) parts. By improving mechanical properties of surface, an increase of abrasion resistance and wear resistance is reached. Longevity and economical aspect have an important role in final useful properties of product. Measurement of surface properties was done by ultra-nanoindentation technique (UNHT3), this is the best tool available right now, this technique is based on instrumented testing. Surface properties were modified by ionized radiation, that caused the creation of crosslinked structure in polyethylene. During radiation a three dimensional network is created, that improves final properties of product such as: hardness, elasticity modulus, thermal stability, etc. During ionized radiation there are two actions that take place at the same time, crosslinking and degradation. Goal of this paper is to consider how radiation intensity affects surface properties (indentation hardness, indentation modulus, deformation work, etc.) Another goal of this paper is to find out the optimal dose of radiation, that will cause more three dimensional crosslinking and less degradation as degradation causes decrease in mechanical properties.

Surface Properties of Crosslinking Polyamide Measured by Micro-Indentation Test

2018 ◽  
Vol 919 ◽  
pp. 111-119
Author(s):  
Martin Ovsik ◽  
Michal Stanek ◽  
Vojtech Senkerik
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Surface Properties ◽  
Electron Beam Irradiation ◽  
Indentation Test ◽  
Polymer Chains ◽  
Beta Radiation ◽  
Cross Linking ◽  
Micro Indentation ◽  
Different Doses

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behavior. This paper studies the effect of different doses of ionizing beta radiation on the micro-mechanical properties of commercially available polyamide. The measured results indicate, that electron beam irradiation is very effective tool for improvement of surface properties of PA6. In terms of micro-mechanical properties, the values of micro-hardness of surface layer increased by 24% at radiation dose of 132 kGy, stiffness of surface micro layer by 26% (132 kGy) as a result of different loads (0.5N and 2N). Improvement of micro-mechanical properties of radiated polyamide has a great significance also for industry. The modified polyamide shifts to the group of materials that have considerably better properties. Its micro-mechanical properties make polyamide ideal for a wide application in areas where higher resistance to wear, creep are required. Commonly manufactured PA6 can hardly fulfil these criteria.

CRITICAL BEHAVIOUR OF THE TRANSVERSE ISING MODEL WITH MODIFIED SURFACE EXCHANGE

2001 ◽  
Vol 15 (04) ◽  
pp. 379-384 ◽  
Author(s):  
J. M. WESSELINOWA ◽  
S. TRIMPER
Keyword(s):  
Monte Carlo ◽  
Surface Layer ◽  
Ising Model ◽  
Exchange Coupling ◽  
Three Dimensional ◽  
Transverse Field ◽  
Function Technique ◽  
Surface Phenomena ◽  
Surface Exchange ◽  
Modified Surface

Using a Green's function technique combined with the transfer-matrix method for the analysis of surface phenomena, we have studied a three-dimensional Ising model in a transverse field with a modified surface exchange coupling. The surface layer-polarization exponent is obtained as β s = 0.775 ± 0.006 which is entirely different from the bulk exponent of β = 0.317 ± 0.006. The results are in agreement with those based on renormalization group arguments and on Monte-Carlo simulations.

The Behaviour of Cross-Linking Filled PA66 by Micro-Indentation Test

2016 ◽  
Vol 699 ◽  
pp. 43-48
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Vojtech Senkerik
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Glass Fiber ◽  
Indentation Test ◽  
Polymer Materials ◽  
Beta Radiation ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Polyamide 66 ◽  
Depth Sensing

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Micro-mechanical changes in the surface layer of glass-fiber filled PA 66 modified by beta radiation were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The specimens were prepared by injection technology and subjected to radiation doses of 0, 33, 66 nad 99 kGy. The change of micro-mechanical properties is greatly manifested mainly in the surface layer of the modified polypropylene where a significant growth of micro-hardness values can be observed. Indentation modulus increased from 1.8 to 3.0 GPa (increasing about 66%) and indentation hardness increased from 87 to 157 MPa (increasing about 80%). This research paper studies the influence of the dose of irradiation on the micro-mechanical properties of semi-crystalline polyamide 66 filled by 30% glass fiber at room temperature. The study is carried out due to the ever-growing employment of this type of polymer.

Research Project Number 33: Investigating the Creative Process in a Microgravity Environment

Leonardo ◽  
2000 ◽  
Vol 33 (3) ◽  
pp. 169-177 ◽  
Author(s):  
Frank Pietronigro
Keyword(s):  
Creative Process ◽  
Three Dimensional ◽  
Space Missions ◽  
Microgravity Environment ◽  
Reduced Gravity ◽  
Human Spirit ◽  
Research Project

The author, an interdiscipli-nary artist, discusses his creation of art in a microgravity environ-ment as part of the 1998 NASA Student Reduced Gravity Flight Program. He discusses his three-dimensional “drift paintings” which floated in the air along with his body in microgravity. The au-thor posits that the transcendent quality of the creative process can help keep the human spirit alive during long-term space missions.

scholarly journals Improvement of Service Quality in the Supply Chain of Commercial Banks—A Case Study in Vietnam

2021 ◽  
Vol 14 (8) ◽  
pp. 357
Author(s):  
Han-Khanh Nguyen ◽  
Thuy-Dung Nguyen
Keyword(s):  
Service Quality ◽  
Commercial Banks ◽  
Three Dimensional ◽  
Sustainable Growth ◽  
Factors Affecting ◽  
Business Operations ◽  
Improve Service Quality

The outbreak of the Covid-19 pandemic caused a serious impact on the business activities of enterprises and households, affecting the operation of banks around the world, especially for capital mobilization from those with savings deposits at commercial banks. In face of the unpredictable developments of the pandemic, many services of banks in Vietnam were also affected, so it has been necessary to make a plan to maintain business operations and respond effectively to these difficulties. In this study, the authors used three research models to form a three-dimensional frame of reference (past, present, and future) to identify, analyze, and evaluate the factors affecting the service quality of commercial banks’ savings deposit mobilization, and to suggest solutions that can minimize risks and improve customer satisfaction for savings deposits at commercial banks, improve service quality to avoid potential long-term risks, as well as maintain sustainable growth and social stability in the future.

scholarly journals Gene and Cell Therapy in Dental Tissue Regeneration

2021 ◽  
Author(s):  
Juan Andrés de Pablo ◽  
Luis Javier Serrano ◽  
Mariano García-Arranz ◽  
Luis Romeu ◽  
Antonio Liras
Keyword(s):  
Cell Therapy ◽  
Bone Morphogenetic Proteins ◽  
Alveolar Bone ◽  
Three Dimensional ◽  
Dental Practice ◽  
Dental Tissue ◽  
Advanced Therapies ◽  
Medical Advances

Advanced therapies hold substantial promise for the treatment of periodontal conditions. Gene therapy has the potential to transfer “therapeutic” genes, which express proteins such as bone morphogenetic proteins, osteoprotegerin, and tissue nonspecific alkaline phosphatase, which is deficient in patients with hypophosphatasia, a condition that affects mineralization of teeth and bone. Transferred genes may also express platelet-derived growth factor, which modulates the growth of periodontal tissue and the alveolar bone. As regards cell therapy, several clinical trials have shown that mesenchymal stem cells, when used with different kinds of scaffolds to enable the required three-dimensional environment, possess a bone regeneration potential that is particularly useful in such disorders as osteoporosis and osteonecrosis, or for regenerating alveolar bone (osseointegration) prior to placing a dental implant. However, much work is still required before these new therapies become true alternatives in routine clinical dental practice. Medical advances require investments, which are usually influenced by the priorities of both politicians and society at large. This will contribute to promoting innovation, efficient treatments, medium- and long-term savings, and a higher quality of life.

Quality of Reamed Surface Using Serrated Blades as Compared to a Conventional Acetabular Reamer

2013 ◽  
Author(s):  
Annie Levasseur ◽  
Jérémie Ménard ◽  
Victor Songmené ◽  
Julio Fernandes ◽  
Yvan Petit
Keyword(s):  
Experimental Testing ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Numerical Control ◽  
Long Term Stability ◽  
Surface Irregularities ◽  
The Stability ◽  
Acetabular Implant

Background: Hip arthroplasty requires the preparation of the acetabular cavity to allow a proper contact between the bone and the implant. It is essential to allow osseointegration and long-term stability of the implant. The aim of this study was to conduct experimental testing to evaluate the quality of reamed surfaces using a serrated blade acetabular reamer as compared to a conventional rasp reamer. Method of Approach: Reaming tests were performed on a computerized numerical control tools machine at a rotational speed of 250 rpm and 3 different penetration speeds: 0.20 mm/s, 0.55 mm/s and 0.90 mm/s. For each reamer, a complete semi-hemispherical hole was perforated in 7 polyurethane samples. The reamed surfaces were digitized with a three-dimensional high resolution (40 μm) self-positioning laser scanner to carry out a quantitative analysis of the surface quality. Results: Results demonstrated that the cutting edge and the penetration speed influence the quality of the reamed surface. The serrated blade was found to reduce surface irregularities (ranging between 0.19 mm to 0.21 mm for the conventional rasp and between 0.07 mm and 0.12 mm for the serrated blades), and to reduce inaccuracies on the reamed cavity diameter (0.13 mm ± 0.05mm for the rasps and 0.06 mm ± 0.03mm for the serrated blade). Conclusions: The use of such tool by the surgeon may influence the stability of the acetabular implant and reduce the risks of revision surgery.

Evaluation Model: Effects from Ocean Garbage Patch to Ocean Environment

2010 ◽  
Vol 113-116 ◽  
pp. 150-154
Author(s):  
Ting Ting Wang ◽  
Yuan Biao Zhang ◽  
Zhi Ning Liang ◽  
Wei Huang
Keyword(s):  
Evaluation Model ◽  
Three Dimensional ◽  
Ocean Water ◽  
Long Term Effects ◽  
Plastic Debris ◽  
Short And Long Term ◽  
Ocean Environment ◽  
Three Dimensional Coordinate

Through the introduction of food chain, our paper analyzed the short and long-term effects that ocean garbage patch provided to ocean environment. We used plastic density, quality of ocean water and the ratio of organisms eating plastic to examine effects of plastic debris. We described effect as a three-dimensional vector and creatively employed the three dimensional coordinate and sphere to explain the effects. Finally, we put forward some feasible measures to relieve the problem.

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