A Simple Model for Predicting Heat Aging of EPDM Rubber

2004 ◽  
Vol 77 (2) ◽  
pp. 242-256 ◽  
Author(s):  
Arnis U. Paeglis
Keyword(s):  
Physical Properties ◽  
Strain Energy ◽  
Physical Property ◽  
Elongation At Break ◽  
Epdm Rubber ◽  
Wide Range ◽  
Rate Relationship ◽  
Property Changes ◽  
Simple Empirical Model

Abstract Heat aging stability is a hallmark of EPDM rubber and a requirement for use in automotive, roofing and other applications. Retention of physical properties after accelerated heat aging is a typical specification for such long-term uses. This paper examines the utility of such tests in predicting results over a range of temperatures, 116 °C, 125 °C, 135 °C and 150 °C, in some cases for as long as 365 days. A simple empirical model was developed to predict the retention of physical properties using fractional strain energy, that is, the ratio of the aged to unaged products of tensile strength and elongation at break. Characteristic rates, an Arrhenius rate relationship and activation energies were determined. This model provides a basis to predict physical property changes over a wide range of temperatures and times, as well as for considerations of equivalent heat aging tests and use in different applications.

Physical Property Changes in Commercial Natural Rubbers during Long Term Storage

2006 ◽  
Vol 79 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Jintana Yunyongwattanakorn ◽  
Jitladda T. Sakdapipanich
Keyword(s):  
Physical Properties ◽  
Storage Time ◽  
Physical Property ◽  
Gel Content ◽  
Long Term Storage ◽  
Property Changes ◽  
Term Storage ◽  
Clear Relation ◽  
Long Storage

Abstract The physical properties during long term storage of selected commercial Standard Thai Rubbers (STR), i.e. STR XL, STR 5L and STR CV60 as high-graded natural rubber (NR), were investigated. Sections of commercial NR were subjected to examination after storage-hardening. STR 5L showed clearly an increase in Mooney viscosity (VR), Mooney relaxtion (MR30), gel content and initial plasticity (P0), higher than that of STR XL. This result suggests that STR 5L exhibits the highest inconsistency in physical properties. The increasing viscosity and gel content of STR 5L and STR XL samples suggest the occurrence of a crosslink structure during storage. STR CV60, known as a viscosity-stabilized NR sample, also showed an increase in VR, gel content, P0, and high PRI value during long storage. These findings indicate that storage-hardening occurred in the rubber samples even after carefully controlled production procedures. As for the different sections of samples, there was no clear relation with gel content with respect to storage time, indicating that depth or positions of specimens in a certain rubber bale did not affect the storage-hardening phenomenon.

The Prediction of Long-Term and Emergency Sealability of Silicone and EPDM Gaskets

2010 ◽  
Author(s):  
Mitsuyuki Nakano ◽  
Haruko Sasaki ◽  
Kanji Hanashima
Keyword(s):  
Power Plant ◽  
Silicone Rubber ◽  
Nuclear Power ◽  
Physical Property ◽  
Rubber Gasket ◽  
Long Term Stability ◽  
Containment Vessel ◽  
Aging Test ◽  
Property Changes

At nuclear power plants, containment vessel acts as pressure barrier in such an emergency as a loss-of-coolant accident. It is important as safety equipment to prevent radiological from leaking outside. Rubber gaskets, which are used for sealing faces of containment vessel, are needed to maintain certain sealability not only in stable condition but also in an emergent situation. Among important characteristics of the rubber gasket are not only physical property changes after general aging test (for example, tensile strength changes after heat resistance test) that indicate long-term stability of gasket itself, but also after radiation resistance test which gives potential to good substitute characteristic in terms of sealability in such cases. Physical property changes after general aging test do not always substitute sealability in an emergency, because they do not reflect effects of radiation. That is why nuclear power plant engineers must choose suitable rubber materials that have high performance in radiation resistance. In Japan, silicone rubber gaskets have been used for containment vessel for a long time since 1970th, but in the United States, ethylene propylene diene terpolymer (EPDM) gaskets have been widely used. NICHIAS has silicone rubber and EPDM materials for containment vessel and these gaskets have been used in nuclear power plant. But it is not obvious why different materials have been used in two countries because few relative comparisons of the two materials have been carried out. Especially silicone rubber and EPDM gaskets have many combinations of chemical compositions, so it is difficult to evaluate gasket suitability for containment vessel. There are many kinds of studies concerning long-term stability and life of gasket, but we all must know what characteristics relate sealability under radiation exposure condition and are suitable for guidepost of sealability under previous condition. This report compares silicone rubber gasket with EPDM gasket on physical property changes under irradiation and thermal treatment. We report compression set test results about one each type of silicone rubber and EPDM gasket under irradiation from Co60. And we also report relationships in physical property changes between irradiation and thermal treatment. Finally NICHIAS predicts long-term and emergency sealability of these gaskets from the results of evaluation. We hope it will be a part of design guideline of rubber gasket for containment vessel.

Runoff, soil loss and soil physical property changes of light textured surface soils from long term tillage treatments

Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 789 ◽  
Author(s):  
IJ Packer ◽  
GJ Hamilton ◽  
TB Koen
Keyword(s):  
Physical Properties ◽  
Soil Loss ◽  
Sandy Loam ◽  
Conservation Tillage ◽  
Physical Property ◽  
Soil Disturbance ◽  
Soil Physical Properties ◽  
Textured Surface ◽  
Direct Drilling

A long-term tillage trial was conducted (1981 to 1987) on loamy textured soils to quantify changes in runoff, soil loss and some soil physical properties due to conservation tillage practices. Two sites were established, one at Cowra on a sandy loam textured soil, and the other at Grenfell on a loamy textured soil. The tillage treatments imposed were direct drilling (DD), reduced tillage (RT) and traditional tillage (TT), with grazing at both sites, and a direct drilling ungrazed (NT) treatment at Cowra only. Runoff and soil loss were measured using a rainfall simulator, and sorptivity (S), saturated hydraulic conductivity (Ksat), bulk density to 40 mm (BD4) and 100 mm (BD10), organic carbon (OC) and water stable aggregates (WSA) were measured annually. Runoff decreased significantly in the minimum soil disturbance treatments (NT and DD) at Cowra. Runoff did not decrease in the stubble incorporation treatments despite a significant increase in OC and WSA. Decreases in runoff were due to the development and maintenance of porosity, particularly macropores. Changes in other soil physical properties were generally not significant owing to temporal variability. The regression relationship between OC and WSA, although significant, had little practical value because of high prediction error. Although improvements in soil physical properties were measured, a period of at least five years of cropping at both sites was required before they became significant and consistent.

scholarly journals Quantifying retrieval uncertainties in the CM-SAF cloud physical property algorithm with simulated SEVIRI observations

2012 ◽  
Vol 12 (2) ◽  
pp. 4311-4340 ◽  
Author(s):  
B. J. Jonkheid ◽  
R. A. Roebeling ◽  
E. van Meijgaard
Keyword(s):  
Physical Properties ◽  
Liquid Water ◽  
Evaluation Studies ◽  
Physical Property ◽  
Retrieval Algorithm ◽  
Ice Clouds ◽  
Cloud Parameters ◽  
Wide Range ◽  
Retrieval Errors ◽  
Multi Phase

Abstract. The uncertainties in the cloud physical properties derived from satellite observations make it difficult to interpret model evaluation studies. In this paper, the uncertainties in the cloud water path (CWP) retrievals derived with the cloud physical properties retrieval algorithm (CPP) of the climate monitoring satellite application facility (CM-SAF) are investigated. To this end, a numerical simulator of MSG-SEVIRI observations was developed that calculates the reflectances at 0.64 and 1.63 μm for a wide range of cloud parameters, satellite viewing geometries and surface albedos. These reflectances are used as input to CPP, and the retrieved values of CWP are compared to the original input of the simulator. It is shown that the CWP retrievals are very sensitive to the assumptions made in the CPP code. The CWP retrieval errors are generally small for unbroken single-phase clouds with COT >10, with retrieval errors of ~3% for liquid water clouds to ~10% for ice clouds. When both liquid water and ice clouds are present in a pixel, the CWP retrieval errors increase dramatically; depending on the cloud, this can lead to uncertainties of 40–80%. CWP retrievals also become more uncertain when the cloud does not cover the entire pixel, leading to errors of ~50% for cloud fractions of 0.75 and even larger errors for smaller cloud fractions. Thus, the satellite retrieval of cloud physical properties of broken clouds and multi-phase clouds is complicated by inherent difficulties, and the proper interpretation of such retrievals requires extra care.

ANACONDA ALLOY 268

Alloy Digest ◽  
1982 ◽  
Vol 31 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Cold Working ◽  
Heat Treating ◽  
Zinc Alloy ◽  
Wide Range ◽  
Copper Zinc ◽  
Cold Worked

Abstract ANACONDA Alloy 268 is a copper-zinc alloy with excellent cold-working properties; it can be cold worked by all the conventional fabrication processes. Its corrosion resistance is excellent-to-good in most environments. This alloy has a wide range of applications including items such as springs, bathroom fixtures, automotive radiators, lamp sockets and sanitary traps. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-442. Producer or source: Anaconda American Brass Company.

CENTRI-CAST GRAY IRON 50

Alloy Digest ◽  
1981 ◽  
Vol 30 (8) ◽  
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Physical Properties ◽  
Machine Tools ◽  
Heat Treating ◽  
Gray Iron ◽  
Centrifugally Cast ◽  
Wide Range ◽  
Nominal Tensile Strength ◽  
Cast Gray Iron

Abstract CENTRI-CAST GRAY IRON 50 is a centrifugally cast gray iron with a nominal tensile strength of 50,000 psi. It is cast in the form of tubing which has a wide range of uses in applications where size and shape are of paramount importance and freedom from pattern cost is an important consideration. Among its many applications are farm machinery, seals, bushings, machine tools and general machinery uses. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-51. Producer or source: Federal Bronze Products Inc..

CENTRI-CAST GRAY IRON 55

Alloy Digest ◽  
1979 ◽  
Vol 28 (9) ◽  
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Physical Properties ◽  
Surface Treatment ◽  
Heat Treating ◽  
Gray Iron ◽  
Centrifugally Cast ◽  
Wide Range ◽  
Nominal Tensile Strength ◽  
Cast Gray Iron

Abstract CENTRI-CAST GRAY IRON 55 is a centrifugally cast gray iron with a nominal tensile strength of 55,000 psi. It is produced in the form of tubing which has a wide range of uses in applications where size and shape are of paramount importance and freedom from pattern cost is an important consideration. Typical applications are seals, bushings, farm machinery, casings and general machinery uses. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-48. Producer or source: Federal Bronze Products Inc..

CHASE 14310

Alloy Digest ◽  
1977 ◽  
Vol 26 (10) ◽  
Keyword(s):  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Heat Treating ◽  
Thermal Softening ◽  
High Conductivity ◽  
Wide Range

Abstract CHASE 14310 is a high-conductivity copper with excellent resistance to thermal softening. It is a deoxidized, electronic grade of copper with excellent formability, weldability and plateability. It is available in strip form and has a wide range of applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-341. Producer or source: Chase Brass & Copper Company Inc..

KUBOTA KNC-03

Alloy Digest ◽  
2010 ◽  
Vol 59 (1) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Kubota KNC-03 is a grade with a combination of high strength and excellent resistance to oxidation. These properties make this alloy suitable for long-term service at temperature up to 1250 deg C (2282 deg F). This datasheet provides information on physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: Ni-676. Producer or source: Kubota Metal Corporation, Fahramet Division. See also Alloy Digest Ni-662, April 2008.

KUBOTA ALLOY HD

Alloy Digest ◽  
2011 ◽  
Vol 60 (12) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Steel Casting ◽  
Casting Alloy

Abstract Kubota Alloy HD (UNS J93005) is a heat-resisting stainless steel casting alloy suitable for long-term service at temperatures up to 1095 deg C (2000 deg F). The nearest wrought equivalent is type 327. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on corrosion resistance as well as casting and joining. Filing Code: SS-1110. Producer or source: Kubota Metal Corporation, Fahramet Division.

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