Factors Influencing the Ozone Resistance of Neoprene Vulcanizates under Flexure

1959 ◽  
Vol 32 (4) ◽  
pp. 1117-1133 ◽  
Author(s):  
R. M. Murray
Keyword(s):  
Dynamic Testing ◽  
Constant Stress ◽  
Ozone Exposure ◽  
Surface Barrier ◽  
Limiting Factor ◽  
Surface Films ◽  
Protective Film ◽  
Dynamic Conditions ◽  
Static Conditions ◽  
Ozone Resistance

Abstract The need for dynamic testing conditions, such as mild flexing, to study the attack of ozone on elastomeric vulcanizates, has become increasingly apparent. Many rubber goods, such as belts, tire sidewalls, and hose, are subjected to intermittent or continuously fluctuating strains in service and to evaluate their ozone resistance under constant stress or strain conditions is unrealistic and often leads to entirely erroneous conclusions. For example, it is well known that under static strain a vulcanizate's ozone resistance is enhanced by compounding with a wax which migrates to its surface and forms a protective film. However, numerous investigators have reported that when a wax film is continuously ruptured by dynamic testing, the vulcanizate is even more vulnerable to ozone attack than if no wax were present. Other surface films also may act detrimentally under dynamic conditions. One such film may form under static exposure by the migration of antiozonants to the surface of a sample where they or their ozone reaction products provide a shield against ozone. Also, diene elastomers, even when not under stress, react with ozone without cracking and it has been postulated that the thin films formed as a result of this reaction are less extensible and consequently more subject to rupture on flexing than the unreacted rubber beneath them. It may well be found that the resistance of any surface barrier to dynamic stresses is the limiting factor for many products in service. Consequently, techniques for testing under dynamic conditions are needed at least to supplement testing under constant stress or strain in ozone. Ozone exposure under dynamic conditions may prove to have analytical advantages over the static method. First, because dynamic tests accelerate ozone attack over that obtained statically even though no increased strain is impressed. This permits the more ozone resistant elastomers to be tested at lower concentrations of ozone than would be possible statically. By testing in more dilute ozone, the correlation between results obtained under atmospheric exposure and the ozone cabinet should be better. Also, it seems likely that compounding ingredients which improve ozone resistance under dynamic conditions should provide improvement under static conditions as well, even though the converse is not necessarily true.

Ozone Resistance of Natural Rubber Vulcanizates. Part II. Influence of Fillers and Waxes

1958 ◽  
Vol 31 (4) ◽  
pp. 874-881 ◽  
Author(s):  
B. I. C. F. van Pul
Keyword(s):  
Natural Rubber ◽  
Side Chains ◽  
Melting Points ◽  
Dynamic Conditions ◽  
Static Conditions ◽  
Natural Rubber Vulcanizates ◽  
Ozone Resistance

Abstract Commerical waxes whose melting points, refractive indexes and numbers of side chains are within the ranges described seem likely to give good ozone protection under static conditions. All waxes lead to worse cracking under dynamic conditions than if none had been included and it is clearly better to use no wax if the rubber is likely to be submitted to intermittent stretching.

scholarly journals The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

2021 ◽  
Vol 13 (3) ◽  
pp. 1554
Author(s):  
Tadas Dambrauskas ◽  
Kestutis Baltakys ◽  
Agne Grineviciene ◽  
Valdas Rudelis
Keyword(s):  
Liquid Medium ◽  
Silica Gel ◽  
Ion Mobility ◽  
Fluoride Removal ◽  
Dynamic Conditions ◽  
Treatment Conditions ◽  
Medium Flow ◽  
Silica Gel Waste ◽  
Fluorine Ions ◽  
Static Conditions

In this work, the influence of various hydroxide and salt additives on the removal of F− ions from silica gel waste, which is obtained during the production of AlF3, was examined. The leaching of the mentioned ions from silica gel waste to the liquid medium was achieved by the application of different techniques: (1) leaching under static conditions; (2) leaching under dynamic conditions by the use of continuous liquid medium flow; and (3) leaching in cycles under dynamic conditions. It was determined that the efficiency of the fluoride removal from this waste depends on the w/s ratio, the leaching conditions, and the additives used. It was proven that it is possible to reduce the concentration of fluorine ions from 10% to <5% by changing the treatment conditions and by adding alkaline compounds. The silica gel obtained after the leaching is a promising silicon dioxide source.

A New Technical Standard Procedure to Measure Stimulation and Gravel-pack Fluid Leak-off under Dynamic Conditions

2015 ◽  
Author(s):  
Mahmoud Asadi ◽  
Brain Ainley ◽  
David Archacki ◽  
Eric Aubry ◽  
Harold Brannon ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Standard Procedure ◽  
Oil And Gas Industry ◽  
Testing Procedure ◽  
Technical Standard ◽  
Gas Wells ◽  
Dynamic Conditions ◽  
Oil And Gas Wells ◽  
Static Conditions ◽  
Gravel Pack

Abstract Historically, leak-off analyses of stimulation fluids have been performed using in-house laboratory procedures. The lack of industry standard procedures to perform leak-off and wall building coefficient analyses of stimulation fluids has introduced inconsistency in both results and reporting for many years. A technical standard adopted in 2006 by both API and ISO for static conditions has provided the oil and gas industry with the first standardized procedure to measure and report leak-off1. However, the more complex testing under dynamic conditions was not addressed. As a result, a group of industry experts have compiled their years of experiences in developing a new technical standard to measure the leak-off characteristics of stimulation and gravel-pack fluids under dynamic flow conditions. Stimulation and gravel-pack fluids are defined, for the purpose of this technical standard, as fluids used to enhance production from oil and gas wells by fracturing and fluids used to place filtration media to control formation sand production from oil and gas wells. Leak-off is the amount of fluid lost to porous media during these operations. The leak-off procedure was developed through the colaberation of several industry companies by evaluating numerous in-house laboratory techniques and conducting round robin testing to ensure that any modifications to these procedures were reliable and repeatable. The new standard provides a step-by-step procedure that includes fluid preparation, experimental equipment design, testing procedure and data analyses for fluids exhibiting viscosity controlled leak-off or wall building characteristics. Example calculations are reviewed within this paper.

scholarly journals Static and Dynamic Performance of Vector Control on Induction Motor with PID Controller: An Investigation on LabVIEW

2021 ◽  
Vol 4 (2) ◽  
pp. 83-96
Author(s):  
Abdillah Aziz Muntashir ◽  
Era Purwanto ◽  
Bambang Sumantri ◽  
Hanif Hasyier FAkhruddin ◽  
Raden Akbar Nur Apriyanto
Keyword(s):  
Vector Control ◽  
Induction Motor ◽  
Pid Controller ◽  
High Reliability ◽  
Load Torque ◽  
Set Point ◽  
Dynamic Conditions ◽  
Low Speed ◽  
Three Phase ◽  
Static Conditions

A three-phase induction motor is often used in everyday life because of its high reliability. However, it is associated with some disadvantages, including difficulties in maintaining constant speed during load changes and speed regulation due to the decoupled system. Therefore, this study aims to adjust the three-phase induction motor control to become a separate amplifier DC motor by setting the vector control using the IFOC method, which changes the coupled to the decoupled system. The speed settings are equipped with a PID controller where its parameters, which are obtained using Ziegler Nichols, produce speed output with fast research time and small steady-state errors. This research was conducted to observe and analyze the performance of a controller based on the IFOC approach with a PID controller at speed differences, with static and dynamic conditions in the entire speed working area. In the first stage of the research, simulation is carried out with static conditions, namely changes in speed variations throughout the work area (low speed to high speed), the next stage is a simulation with dynamic conditions, which is to provide changes in the value of the load torque when the system is operating. The simulation result carried out with LabVIEW shows a response time of 1.13 ms, a settling time of 9.9 ms, and a steady error of 0.4% at the 500 Rpm set point. It also indicated dynamic characteristics with a recovery time of 4.9 ms at the 300 Rpm set point. When operated at low speed, IFOC with PID controller has a stable response. But In dynamic conditions, the use of a PID controller is considered unsuitable. This is because the PID controller is less fast and less robust in responding to the system when conditions change in the value of the load torque.

scholarly journals On some pre-Cambrian metadolerites from the central Ivigtut region SW Greenland

1965 ◽  
Vol 52 ◽  
pp. 1-42
Author(s):  
E Bondesen ◽  
N Henriksen
Keyword(s):  
Shear Zones ◽  
Metamorphic Grade ◽  
Amphibolite Facies ◽  
Dynamic Conditions ◽  
Static Conditions

After their consolidation, the Ketilidian gneisses were transversed by several generations of tensional, doleritic dykes-the Kuánitic dykes. During a later episode (the Sánerutian) these dykes were metamorphosed to varying degrees of alteration which increase in the described area from west to east. Along a specific metadolerite, which can be traced approx. 40 km, the metamorphic grade changes from greenschist to amphibolite facies. In the western parts static conditions and in the eastern parts dynamic conditions, prevailed during the alteration. Sánerutian shear zones in the eastern parts depict the dynamic conditions found here.

scholarly journals Using natural aluminosilicate (vermiculite) sorbent for purifying waste water from antibiotics

2022 ◽  
Vol 6 (4) ◽  
pp. 387-394
Author(s):  
D. S. Galchenko ◽  
M. G. Smirnova ◽  
L. I. Sokolova
Keyword(s):  
Waste Water ◽  
Total Concentration ◽  
Total Content ◽  
Fish Farming ◽  
Model System ◽  
Fish Processing ◽  
Dynamic Conditions ◽  
Natural Aluminosilicate ◽  
Antibiotics Detection ◽  
Static Conditions

The problem of wastewater treatment from residual antibiotics is of particular relevance, since these drugs are used in many agricultural sectors. Antibiotics get into water, animal and human bodies, where they can accumulate negatively affecting health. The aim of this article is to study the possibility of using natural aluminosilicate vermiculite sorbent from the Koksharovskoye field (Primorsky Region) for purifying fish processing and fish farming enterprises’ waste water from antibiotics (chloramphenicol, tetracycline, cefazolin, cefuroxime, ceftriaxone, cefepime and and ciprofloxacin) under static and dynamic conditions. The study was carried out on a model wastewater system with injected antibiotics. The purification ability of the model system using the method of spectrophotometric antibiotics detection is analyzed. Under static conditions, the total content of antibiotics varied from 0.25 mg to 1.00 mg per 1 g of sorbent. Under dynamic conditions, the antibiotic content was 0.025 mg per 1 g of sorbent. High values of absorption for all studied antibiotics, except for chloramphenicol, were achieved both in static and dynamic modes. For chloramphenicol, when examined under static conditions, the maximum absorption rate was 45% with the minimum total concentration of antibiotics. With an increase in the load on the sorbent, the degree of absorption decreased to 3%. Thus, vermiculite modified with 7% hydrochloric acid is a promising sorbent for cleaning water bodies from residual antibiotics.

scholarly journals The ozonolysis of primary aliphatic amines in fine particles

2008 ◽  
Vol 8 (5) ◽  
pp. 1181-1194 ◽  
Author(s):  
J. Zahardis ◽  
S. Geddes ◽  
G. A. Petrucci
Keyword(s):  
Fine Particles ◽  
Reaction System ◽  
Tropospheric Chemistry ◽  
Ozone Exposure ◽  
Surface Barrier ◽  
Secondary Amide ◽  
Tertiary Amide ◽  
Aerosol Mass ◽  
Criegee Intermediates ◽  
Species Specific

Abstract. The oxidative processing by ozone of the particulate amines octadecylamine (ODA) and hexadecylamine (HDA) is reported. Ozonolysis of these amines resulted in strong NO2– and NO3– ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitroalkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3– (HNO3). For ozonized mixed particles containing ODA or HDA + oleic acid (OL), with pO3≥3×10–7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines) and stabilized Criegee intermediates (SCI) or secondary ozonides (for amides) from the fatty acid. The routes to amides via SCI and/or secondary ozonides were shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s). This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g.~NO2, NO3), formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

Studies on the Fabrication and Stab Resistance Characterization of Novel Thermoplastic-Kevlar Composites

2008 ◽  
Vol 136 ◽  
pp. 83-92 ◽  
Author(s):  
M.V. Hosur ◽  
Jessie B. Mayo Jr. ◽  
E. Wetzel ◽  
S. Jeelani
Keyword(s):  
Dynamic Testing ◽  
Hot Press ◽  
Good Resistance ◽  
Puncture Resistance ◽  
Dynamic Conditions ◽  
Low Resistance ◽  
Film Type ◽  
National Institute Of Justice ◽  
Stab Resistance

Kevlar has demonstrated the ability to protect well against ballistic threats but has low resistance to puncture. Correctional Kevlar has shown good resistance to puncture. However, the fabric is expensive, difficult to manufacture because of its tight weave construction, and has limited protection against ballistic threats. In an effort to produce materials that are less bulky, more flexible, and resistant to puncture, thermoplastic-Kevlar (TP-Kevlar) composites have been examined. Kevlar fabric was impregnated with thermoplastic film using a hot press to produce the composites. Static and dynamic puncture resistant properties of the TP-Kevlar composites were investigated using a National Institute of Justice (NIJ Standard 0115.00) Stab Tower. The TP-films used in this study were polyethylene, Surlyn, and co extruded-Surlyn, which is a co extrusion of Surlyn and polyethylene. Response of the polyethylene (PE)-Kevlar composites, Surlyn-Kevlar composites, and co extruded (COEX)-Kevlar composites to spike and knife threats under static and dynamic conditions were compared with that of neat Kevlar. The infusion of thermoplastic films into the Kevlar fabric was shown to dramatically increase puncture resistance during quasi-static and dynamic testing with spikes. The TP-film type also made a difference when examining the resistance on a comparative basis of the TP-Kevlar targets. The TP-Kevlar composite targets showed more resistance to quasi-static spike testing than quasi-static knife testing. Weapon comparisons revealed that the TP-Kevlar composite targets had more resistance to dynamic knife testing than dynamic spike testing.

Development of Novel Test Methodology to Understand the Mechanisms of Halite Inhibition and Environmentally Acceptable Halite Scale Inhibitors for High Temperature Application

2014 ◽  
Author(s):  
Kimberley Ho ◽  
Tao Chen ◽  
Ping Chen ◽  
Thomas Hagen ◽  
Harry Montgomerie ◽  
...  
Keyword(s):  
High Temperature ◽  
Test Procedure ◽  
Dynamic Test ◽  
Operation Time ◽  
Field Conditions ◽  
Dynamic Conditions ◽  
Test Methodology ◽  
Static Conditions ◽  
Batch Treatment ◽  
Nucleation Growth

Abstract Halite deposition is most commonly observed in gas/gas condensate fields with low water cut, high TDS produced brines and high temperature. Halite is notoriously difficult to inhibit and there are limited studies focused on halite due to it being incredibly challenging to have an effective test methodology under laboratory conditions that reflect the field conditions. The mechanisms of halite inhibition are unclear. In the published literature, static jar testing is primarily used to evaluate the performance of halite inhibitors. It is not representative of dynamic field conditions and provides limited information of halite inhibition. A new methanol driven dynamic test methodology has been developed alongside a novel jar test procedure, which together provides an effective methodology to evaluate halite inhibition under both static and dynamic conditions and provides an insight into the understanding of the mechanisms of halite inhibition. Using these novel test methodologies, four short-listed inhibitor chemistries including environmentally acceptable inhibitors were assessed and categorised into two types based on the understanding of the mechanism. ➤ Nucleation/growth inhibitors. Inhibitors reduce the nucleation/growth of halite crystals and give good performance under both static and dynamic test conditions.➤ Dispersion inhibitors. Inhibitor doesn't stop the nucleation/growth of halite crystals and gives poor performance under static conditions, but good performance under dynamic conditions due to dispersion effect. Both types of halite inhibitors have been successfully deployed in the fields through continuous injection or batch treatment. Coreflood tests were carried out to confirm the potential risk of formation damage during downhole batch treatment. Other deployment methods have been discussed such as through methanol injection line as both inhibitors are fully methanol compatible. This paper will give a comprehensive study of halite inhibition for challenged wells, including prediction, novel methodology, program of laboratory qualification, mechanism understanding and field deployment, coupled to the development of a chemical technology toolbox to design field halite applications. The value that a fuller understanding of halite control gives the industry is the ability to reduce/eliminate water wash application to control halite formation and so improve well operation time. If halite inhibition is considered at the capex phase of field development, provisions can be made for chemical injection facilities to maintain uninterrupted production.

Sign in / Sign up

Export Citation Format

Share Document