Quantitative Evaluation of Emulsion Styrene-Butadiene Rubbers and Compounding Variables by Controlled Mixing

1976 ◽  
Vol 49 (1) ◽  
pp. 1-11 ◽  
Author(s):  
S. B. Turetzky ◽  
P. R. Van Buskirk ◽  
P. F. Gunberg
Keyword(s):  
Flow Behavior ◽  
Mixing Time ◽  
Major Constituent ◽  
Time Profiles ◽  
Work Input ◽  
Unit Work ◽  
Work Concept ◽  
Styrene Butadiene ◽  
Temperature Time ◽  
Loading Procedure

Abstract Work reported recently described a “unit work” concept, according to which the flow behavior of a rubber-carbon black mixture was shown to be a function of the mixing work input. These results were shown to be independent of the size of the mixer, the speed of the mixer, and mixing time so long as the temperature-time profiles were similar, the same loading procedure was employed, and the same loading volume percentages were used. This concept provides a means to characterize not only the effect of various polymers, extenders, fillers, and minor additives, but also the uniformity of a given major constituent, which, in the case of an elastomer, may be a processability index. The work described in this paper is the application of the unit work concept to some of these areas : emulsion styrene-butadiene polymers, extenders, and fillers. By means of this concept of mixing, laboratory investigation can be translated, not only qualitatively, but much more important, quantitatively, into factory operations. The effects of polymer molecular weight and bound-styrene content changes, as well as changes in carbon blacks, such as those typified by the new tread blacks, can be investigated in the laboratory, and compounding adjustments can be made there, so that factory production time is not taken for new compound development.

A Model of Tissue Charring During Interstitial Laser Photocoagulation: Estimation of the Char Temperature

1999 ◽  
Author(s):  
William M. Whelan ◽  
Douglas R. Wyman
Keyword(s):  
Laser Photocoagulation ◽  
Continuous Wave ◽  
Laser Energy ◽  
Ex Vivo ◽  
Thermal Gradients ◽  
Tissue Water ◽  
Time Profiles ◽  
Interstitial Laser Photocoagulation ◽  
Interstitial Laser ◽  
Temperature Time

Abstract Interstitial laser photocoagulation (ELP) was performed ex vivo in lean bovine muscle by delivering 1.5 W of continuous-wave 1064 nm Nd:YAG laser energy from a 400 μm core plane-cut optical fiber. The strategy for determining the char temperature involved measuring temperatures where thermal gradients were reduced, and extracting times at which temperature-time profiles displayed interesting nonlinear changes. These times were used to guide a finite difference thermal model, calculating transient temperatures based on two physical descriptions of tissue charring. Modifications in the optical and thermophysical properties due to tissue coagulation (T ≥ 60 °C) and vaporization of tissue water (T ≥ 100°C), respectively, were considered. By placing measured charring dimensions, 2.0 ± 0.3 mm, on calculated temperature-distance profiles, a tissue charring temperature of 414 ± 92°C was estimated.

scholarly journals Preparation of Hydrogen Electrodes of Solid Oxide Cells by Infiltration: Effects of the Preparation Procedure on the Resulting Microstructure

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 131 ◽  
Author(s):  
Bartosz Hołówko ◽  
Jakub Karczewski ◽  
Sebastian Molin ◽  
Piotr Jasiński
Keyword(s):  
Porous Scaffold ◽  
Complex Structure ◽  
Solid Oxide ◽  
Homogeneous Material ◽  
Porous Scaffolds ◽  
Functional Layer ◽  
Time Profiles ◽  
Supporting Layer ◽  
Infiltration Technique ◽  
Temperature Time

In this work, the infiltration technique was used to produce hydrogen electrodes for solid oxide cells. Different infiltration methodologies were tested in order to try to shorten the infiltration cycle time. The porous scaffolds used for infiltration were based on highly porous yttria-stabilized zirconia (YSZ) obtained by etching the reduced nickel from the Ni-YSZ cermet in HNO3 acid. The support had a complex structure which included a ~130 µm porous functional layer with small pores and a ~320 µm thick supporting layer with large pores. Infiltrations have been carried out using aqueous nickel nitrate solutions. Various infiltration procedures were used, differing in temperature/time profiles. The results show that slow evaporation is crucial for obtaining a homogeneous material distribution leading to high-quality samples. A longer evaporation time promotes the proper distribution of nickel throughout the porous scaffold. The shortening of the heat treatment procedure leads to blockage of the pores and not-uniform nickel distribution.

scholarly journals DEPENDENCES OF SMA MIXTURE AND ITS BITUMINOUS BINDER PROPERTIES ON BITUMEN BATCHING SYSTEM, MIXING TIME AND TEMPERATURE ON ASPHALT MIXING PLANT

2013 ◽  
Vol 19 (6) ◽  
pp. 862-872 ◽  
Author(s):  
Justas Bražiūnas ◽  
Henrikas Sivilevičius ◽  
Romualdas Virbickas
Keyword(s):  
Mixing Time ◽  
Asphalt Binder ◽  
Key Factors ◽  
High Pressure Pump ◽  
Working Temperature ◽  
Mastic Asphalt ◽  
Batch Type ◽  
Degree Of Oxidation ◽  
Stone Mastic Asphalt ◽  
Temperature Time

Bitumen holds the aggregate in hot mix asphalt (HMA). Without asphalt binder, HMA would simply be crushed stone or gravel. A bitumen batching system (BBS) is comprised of bitumen storage, transportation, weighing and discharge equipment in an asphalt mixing plant (AMP). The function of the equipment is to batch the binder heated up to working temperature and to discharge it into a mixer in batches. In the entire system, the binder is exposed to high temperature and oxygen. Bitumen is slowly oxidized when it is in contact with oxygen. The degree of oxidation is highly dependent on temperature, time and thickness of a bitumen film. This article models the key factors influencing on the dynamics of bitumen oxidation in BBS equipment. Stone mastic asphalt (SMA) mixture was produced from the same materials according to the same job-mix formula (JMF) in neighbouring batch type AMP by changing the mixing time of materials from 20 to 60 s. Bitumen binder was separated from the taken SMA samples and its gradation was identified. Thus, Marshall specimens were produced and tested. Penetration Pen25 of bitumen binder recovered in rotary evaporator, softening point Tsp was determined and penetration index Ip was calculated. The presented findings of experimental investigation show that the properties of bitumen binder in BBS working at two different technologies changed inconsistently. Due to gravitation, the bitumen intensively flowing into a mixer (BBS1) is impacted by oxidation more than the bitumen batched by a high-pressure pump (BBS2).

scholarly journals Retorting conditions affect palatability and physical characteristics of canned cat food

2017 ◽  
Vol 6 ◽  
Author(s):  
Esther A. Hagen-Plantinga ◽  
Denmark F. Orlanes ◽  
Guido Bosch ◽  
Wouter H. Hendriks ◽  
Antonius F. B. van der Poel
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Physicochemical Characteristics ◽  
Physical Characteristics ◽  
Physical Parameters ◽  
Time Profiles ◽  
Temperature Time

AbstractThe effects of different temperature and time conditions during retorting of canned cat food on physicochemical characteristics and palatability were examined. For this purpose, lacquer cans containing an unprocessed loaf-type commercial cat food were heated in a pressurised retorting system at three specified temperature–time profiles (113°C/232 min, 120°C/103 min and 127°C/60 min) to equal a similar lethality (F0 value = 30). Physicochemical properties (viscosity, texture, particle size, pH) were determined, and a 10 d three-bowl palatability test was performed with ten European shorthair cats. Retorting at 113°C/232 min resulted in differences in all the physical parameters examined (<viscosity, firmness, adhesiveness, and > particle size). Significant pH differences were observed (6·53, 6·63 and 6·66 for T113/232, 120 and 127°C, respectively). Preference ratios were 0·38, 0·31 and 0·31 for T113/232, 120 and 127°C, respectively (P = 0·067). It can be concluded that different retorting temperature–time profiles with equal F0 value significantly affect physical characteristics and tended to affect palatability of moist cat food.

Chitosan-Aluminum Monostearate Composite Dispersion Characteristics

2012 ◽  
Vol 528 ◽  
pp. 233-236
Author(s):  
Kotchamon Yodkhum ◽  
Thawatchai Phaechamud
Keyword(s):  
Particle Size ◽  
Fatty Acid ◽  
Ph Value ◽  
Flow Behavior ◽  
Mixing Time ◽  
Buffer Solution ◽  
Solution Ph ◽  
Conjugate System ◽  
Mean Particle Size ◽  
Chitosan Concentration

Fatty acids have been used as additive for modifying chitosan-based system particularly in hydrophobic manner. Generally, techniques for preparing chitosan-fatty acid conjugate system are take time, involved with high temperature and high shear force and need some surfactants. In this study, alternative technique for simply blending chitosan with fatty acid was performed by taking advantage of ionization of metal stearate and chitosan in acidic condition. Metal stearate used in this study, aluminum monostearate (Alst), was dispersed in chitosan dissolved in lactate buffer solution pH 4.5 with various concentrations of chitosan. Physicochemical properties such as pH value, viscosity and rheology, morphology and particle size of the dispersions were characterized. The pH value and viscosity of the chitosan solutions was higher as the chitosan concentration was increased. For the dispersions, their pH value was not changed by mixing time but their viscosity was decreased by mixing time. All dispersions exhibited Newtonian flow behavior. Larger mean particle size of the dispersions was observed when the mixing time was longer. At higher chitosan concentration, mean particle size of the aggregated chitosan-stearate particles was smaller than the lower chiotsan concentration systems

PHASE SELECTIVE LOCALIZATION OF FILLER IN TERNARY RUBBER BLENDS

2011 ◽  
Vol 84 (1) ◽  
pp. 41-54 ◽  
Author(s):  
H. H. Le ◽  
S. Ilisch ◽  
D. Heidenreich ◽  
K. Osswald ◽  
H-J. Radusch
Keyword(s):  
Mechanical Performance ◽  
Mixing Time ◽  
Styrene Butadiene Rubber ◽  
Experimental Investigations ◽  
Subsequent Stage ◽  
Butadiene Rubber ◽  
Rubber Blends ◽  
Selective Localization ◽  
Styrene Butadiene

Abstract The present work introduces a new concept based on the analysis of the rubber–filler gel for the determination of the phase selective filler localization in ternary rubber blends. Natural rubber (NR)/styrene–butadiene rubber (SBR)/ethylene–propylene rubber (EPDM) blends filled with silica were the focus of the experimental investigations. Because of the higher wetting rate of the NR component to silica, in the first stage of the preparation of SBR/NR/EPDM blends, more silica is found in the NR phase than in the SBR and EPDM phase. In the subsequent stage, silica is transferred from the NR phase to the SBR phase until the loosely bound NR-layer at the silica surface is fully replaced by SBR molecules. An extremely low amount of silica was found in the EPDM phase because of the poor EPDM–silica interaction. After a long mixing time, a large amount of silica whose surface was not yet wetted by any rubber phase could be found in the composites that can lead to fatal effects on the mechanical performance of the composites.

Optimization of heating schedules in pyrolytic binder removal from ceramic moldings

2000 ◽  
Vol 15 (2) ◽  
pp. 449-457 ◽  
Author(s):  
J. H. Song ◽  
J. R. G. Evans ◽  
M. J. Edirisinghe ◽  
E. H. Twizell
Keyword(s):  
Heating Rate ◽  
Degradation Products ◽  
Ambient Pressure ◽  
Extended Model ◽  
Heating Rates ◽  
Binder Removal ◽  
Time Profiles ◽  
Removal Time ◽  
Allowable Rate ◽  
Temperature Time

A model that finds the maximum permissible heating rate for pyrolysis of ceramic moldings is extended to produce multi-segment temperature–time profiles to minimize the binder removal time. The degradation of the polymer and the diffusion of degradation products in solution to the free surface in a cylinder containing 50 vol% alumina and polyalphamethylstyrene is considered. The theory has previously been validated experimentally for fixed heating rates for cylindrical and flat plate geometries and for overpressure debinding. The extended model, presented here, calculates the vapor pressure of monomer over solution and modifies the heating rate to keep this just below ambient pressure. In this way, the temperature follows the maximum allowable rate at each stage to prevent boiling and hence the incidence of defects.

Analysis of the Performance of Ionic Liquids in Cooling Loops

2007 ◽  
Author(s):  
Mihir Sen ◽  
Samuel Paolucci ◽  
Wenjun Liu
Keyword(s):  
Ionic Liquids ◽  
Fluid Velocity ◽  
Pressure Rise ◽  
Heat Rate ◽  
Physical Parameters ◽  
Fluid Properties ◽  
Work Input ◽  
Unit Work ◽  
Cooling Loops ◽  
Quantity Of Heat

Liquids are often pumped in closed loops to transfer heat from a high temperature source to a low temperature sink. They operate at low Reynolds number when the diameter of the pipe is small, the fluid velocity is low, or when the working liquid is very viscous. Ionic liquids, though environmentally friendly, typically have viscosities much larger than water. An analytical study is made of the process for the purpose of determining what the important physical parameters of the system are that will enable the largest quantity of heat to be transferred for unit work expended. For this purpose, a loop is considered that has a pump that generates a certain pressure rise and two heat exchangers, one for heating the fluid and the other for cooling it. Laminar flow that is fully-developed hy-drodynamically and thermally is assumed. The analysis is based on constant fluid properties, and analytical expressions are obtained for the heat rate and the work input.

Silicon Temperature and Thermal Gradients Measurements in a Rapid Thermal Processor Operating at Atmospheric Pressure or in Vacuum

1987 ◽  
Vol 92 ◽  
Author(s):  
J-M. Dilhac ◽  
C. Ganibal ◽  
A. Martinez
Keyword(s):  
Thermal Radiation ◽  
Experimental Evidence ◽  
Thermal History ◽  
Atmospheric Pressure ◽  
Temperature Drop ◽  
Gas Pressure ◽  
Optical Pyrometer ◽  
Thermal Gradients ◽  
Time Profiles ◽  
Temperature Time

ABSTRACTTemperature-time profiles obtained by an optical pyrometer and a mechanically contacted thermocouple are first presented it appears that the thermocouple response is sensitive to the pressure in the processing chamber. The authors suggest that, in vacuum, the thermocouple is thermally isolated from the wafer, until the temperature is high enough for thermal radiation exchanges to occur. Experimental evidence of the influence of thermal history, and of gas pressure and flow, on temperature drop at periphery of the wafer is then given.

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