The Effect of Cure Conditions on the Strength of Ebonite Rubber Network

2005 ◽  
Vol 78 (4) ◽  
pp. 724-735 ◽  
Author(s):  
Cattaleeya Pattamaprom ◽  
Duangkamol Dechojarassri ◽  
Worsak Kanok-Nukulchai
Keyword(s):  
Mechanical Properties ◽  
Nitrogen Atmosphere ◽  
Curing Conditions ◽  
Household Products ◽  
Structural Applications ◽  
Before And After ◽  
Cure Time ◽  
Long Time ◽  
Compression Mold ◽  
Crosslink Densities

Abstract Although ebonite has been discovered for a long time, its applications were still limited to some household products. Recently, ebonite rubber has become of interest, especially for structural applications due to its high and adjustable strength and rigidity. The rigidity can be enhanced by several folds by utilizing appropriate curing conditions. In this study, we investigate the effect of curing conditions on the mechanical properties of ebonite at various cure time. Here, the crosslink densities were determined qualitatively both before and after compression cycles to investigate the change in crosslink networks. After the pre-molding stage, the curing process was either continued in the compression mold, in the air-oven, or under nitrogen atmosphere. For the compression-mold and nitrogen-atmosphere curing, crosslink densities and the compressive moduli increased significantly with cure time, whereas, for air-oven curing, only slight increases in the afro-mentioned properties were observed. After completing four compression cycles, the crosslink density and mechanical properties remain high only when curing was done in the compression mold. Therefore, curing under pressure as in the compression mold for a prolonged time could be a mean in boosting the mechanical properties of ebonite.

Mechanical characteristics and surface elemental composition of a Yasargil titanium aneurysm clip after long-term implantation

2010 ◽  
Vol 112 (6) ◽  
pp. 1260-1262 ◽  
Author(s):  
Yasunari Otawara ◽  
Kuniaki Ogasawara ◽  
Hiroshi Kashimura ◽  
Yoshitaka Kubo ◽  
Akira Ogawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Mechanical Characteristics ◽  
Bending Test ◽  
Corrosion Resistant ◽  
Aneurysm Clip ◽  
Before And After ◽  
Long Time ◽  
And Control

The mechanical properties of titanium-alloy aneurysm clips after long-term implantation in the human cranium are unclear. The characteristics of a Yasargil titanium aneurysm clip were evaluated after long-term implantation for 12 years in a patient with a cerebral aneurysm. The closing forces of the retrieved clip before and after implantation were approximately equal. The bending test showed no differences between the retrieved and control clips. Titanium oxide and calcium were identified on the surface of the retrieved clip, which indicated the formation of corrosion-resistant layers. Titanium-alloy clips retain their mechanical properties in the human cranium for a long time.

scholarly journals Synthesis of Geopolymers from Mechanically Activated Coal Fly Ash and Improvement of Their Mechanical Properties

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 791
Author(s):  
Mitsuaki Matsuoka ◽  
Kaho Yokoyama ◽  
Kohei Okura ◽  
Norihiro Murayama ◽  
Masato Ueda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Mechanical Activation ◽  
Power Plants ◽  
Raw Materials ◽  
Coal Fly Ash ◽  
Fine Powder ◽  
Acid Resistance ◽  
Curing Conditions ◽  
Long Time

Coal fly ash is a spherical fine powder by-product discharged from coal-fired power plants. When coal fly ash is used as raw materials for the synthesis of geopolymers, there are practical problems associated with the stable surface of the particles that do not allow the production of geopolymers with sufficient strength. A long-time is also required for the curing. In this study, we aim to promote the curing reaction of geopolymers by activating the surface of coal fly ash particles. By mechanically activating the surface of coal fly ash particles using an attrition-type mill, the dissolution of Si4+ and Al3+ in coal fly ash is promoted, and the acceleration of the reaction taking place during curing is also anticipated. The surface morphology and crystal phase of coal fly ash particles change with the use of an attrition-type mill. The mechanical activation results in improvement of the compressive strength and the acid resistance under milder curing conditions by the densification of the hardened body. Thus, it is clearly shown that mechanical activation is effective for the production of geopolymers with beneficial mechanical properties under milder curing conditions.

Flame Retardant Protective Coating Applied in Textile 100% Acrylic Fabrics

2009 ◽  
Vol 1242 ◽  
Author(s):  
M. Olvera-Gracia ◽  
T. Kryshtab ◽  
A.M. Paniagua-Mercado ◽  
J. Aguilar-Hernández
Keyword(s):  
Mechanical Properties ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Textile Fabrics ◽  
Infra Red ◽  
Before And After ◽  
Long Time

ABSTRACTTextile 100 % acrylic fabrics have been used in tapestry for a long time. One of the drawbacks of this type of fabrics is its great flammability. Textile fabrics are coated with flame retardant in order to reduce the flammability. We present some results concerning the use of commercial products (Flame-Out, Borax (Na2B4O5(OH)4•8H2O), and Hexametaphosphate of Sodium (Na16P14O43) as flame retardants for textile 100 % acrylic fabrics. The flame retardant capabilities, mechanical properties and structural characteristics of the textile fabrics before and after the use of these products were investigated throughout the special textile methods for inflammability and mechanical resistibility as well as infra-red spectroscopy, X-ray diffraction and scanning electronic microscopy. After the use of the flame retardants the mechanical properties of the fabrics were improved or at least remained the same as compared to fabrics without any treatment. The use of Borax / Hexametaphosphate from Sodium /Water results in the essential increase of combustion retardation time about 2 minutes as compared with 8 seconds for untreated fabrics.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

UNS A97075

Alloy Digest ◽  
1986 ◽  
Vol 35 (7) ◽  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Good Resistance ◽  
Temperature Performance ◽  
Structural Applications ◽  
Structural Parts ◽  
Very High

Abstract UNS No. A97075 is a wrought precipitation-hardenable aluminum alloy. It has excellent mechanical properties, workability and response to heat treatment and refrigeration. Its typical uses comprise aircraft structural parts and other highly stressed structural applications where very high strength and good resistance to corrosion are required. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on low temperature performance as well as forming, heat treating, and machining. Filing Code: Al-269. Producer or source: Various aluminum companies.

WC-3015 Alloy

Alloy Digest ◽  
1974 ◽  
Vol 23 (5) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Base Alloy ◽  
Heat Treating ◽  
Rolled Sheet ◽  
Good Oxidation Resistance ◽  
Structural Applications ◽  
Cold Rolled

Abstract WC-3015 is a columbium-base alloy developed for structural applications in high-temperature oxidizing environments. It is characterized by good oxidation resistance, good mechanical properties and compatibility with silicide coatings. Cold-rolled sheet can be joined and welded without cracking. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-21. Producer or source: Wah Chang, a Teledyne Corporation.

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

scholarly journals Physiological and Psychological Effects of Watching Videos of Different Durations Showing Urban Bamboo Forests with Varied Structures

2020 ◽  
Vol 17 (10) ◽  
pp. 3434
Author(s):  
Yuqian Wang ◽  
Mingyan Jiang ◽  
Yinshu Huang ◽  
Zhiyi Sheng ◽  
Xiao Huang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Skin Conductance ◽  
Human Body ◽  
Stable State ◽  
Mean Value ◽  
Psychological Effects ◽  
Physiological Indicators ◽  
Psychological Indicators ◽  
Before And After ◽  
Long Time

This study illustrated the physiological and psychological effects of watching videos of different durations showing bamboo forests with varied structures. Physiological indicators, including EEG (electroencephalogram), blood pressure, skin conductance, and pulse, were monitored in 180 Chinese university students (mean age: 20.72 ± 2.56 years) while they were watching bamboo videos. Before and after watching the videos, their psychological indicators, including positive and negative moods, were measured using the Profile of Mood States questionnaire. After watching the bamboo videos of different durations, all of the physiological indicators responded to the stimulation after only 1 min. The indicators showed different trends at 1, 3 and 5 min. EEG decreased and then was maintained at a stable level after 1 min, and the high β, low β, and α waves had no significant differences between 1, 3 and 5 min. Blood pressure dropped to a stable state after 3 min, and the decline was significantly different greater after 3 min than after 1 min. Skin conductance increased for 1 to 5 min, and it did not stabilize after a long time (5 min). Pulse decreased after 1 min but increased after 5 min. After watching the videos with bamboo of varying structures, the physiological and psychological indicators showed significantly different changes. Skin conductance significantly increased (mean value: 6.78%), and the amount of sweat was more effectively reduced, thereby reducing tension, when the students viewed videos of sympodial bamboo forests compared with monopodial bamboo forests. Bamboo forests with a higher canopy density (0.83–0.85) could significantly decrease α waves (mean value: 1.50 Hz), relaxing the human body. High β and low β waves showed greater decreases, with tension reduced more effectively, when bamboo forests with a low tilt ratio (< 1.5%) were viewed. Bamboo forests with neat undergrowth could have more beneficial physiological and psychological effects on the human body.

Elastomer nanocomposites based on NBR/BR/nanoclay: morphology and mechanical properties

2013 ◽  
Vol 33 (2) ◽  
pp. 133-139 ◽  
Author(s):  
Shohreh Tolooei ◽  
Ghasem Naderi ◽  
Shirin Shokoohi ◽  
Sedigheh Soltani
Keyword(s):  
Mechanical Properties ◽  
Polymer Chains ◽  
Butadiene Rubber ◽  
Cure Characteristics ◽  
Fluid Uptake ◽  
Roll Mill ◽  
Dispersion State ◽  
Cure Time ◽  
Diffraction Patterns ◽  
Nanoclay Content

Abstract Ternary elastomer nanocomposites based on acrylonitrile butadiene rubber (NBR), polybutadiene rubber (BR) and two types of nanoclay (Cloisite 15A and Cloisite 30B) were prepared using a laboratory scale two-roll mill. The effects of nanoclay composition on the cure characteristics, mechanical properties and morphology of NBR/BR (50/50) nanocomposite samples containing 3, 5, 7 and 10 wt% nanoclay were investigated. According to the cure characteristics both types of nanoclay caused a reduction in the scorch time and optimum cure time of the nanocomposite compound. X-ray diffraction patterns of all samples suggested the intercalation of polymer chains into the silicate layers. This was confirmed by transmission electron microscopy (TEM) micrographs. Dynamic mechanical thermal analysis (DMTA) was utilized to study the dispersion state of nanoclay within the elastomer blend matrix. The results showed the development of mechanical properties with the establishment of interactions between nanoclay and polymer chains. Antiknock and brake fluid uptake were also reduced with increasing the nanoclay content.

Influence of ageing treatment on microstructure, mechanical properties and adhesive wear behaviour of 6063 aluminium alloy

2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
High Speed ◽  
Al Alloys ◽  
Wear Behaviour ◽  
Al Alloy ◽  
Strain Ageing ◽  
Content Type ◽  
Static Strain ◽  
Structural Applications

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.

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