Modeling of Oxidative Aging Behavior of Asphalts from Short-Term, High-Temperature Data as a Step toward Prediction of Pavement Aging

The oxidative aging data collected during the Strategic Highway Research Program have been analyzed in terms of kinetics of viscosity change with time and temperature. Changes in viscosity have been used as the measure of the progress of aging. The objective is to model viscosity increases accurately enough to be able to predict aging (in terms of viscosity changes) at pavement temperatures from short-term test data acquired at high temperature. This involved constituting a mathematical model, based on oxidative reactions, and a nonlinear regression of the data to test predictability of the proposed model. Clearly, there is a point beyond which viscosity change becomes independent of time, but no data were collected to that extent. Separately, it has been shown that oxidation of aliphatic sulfide to sulfoxide and oxidation of benzylic carbon to carbonyl are the principal chemical reactions that contribute to an increase in viscosity. The data fit the proposed equation sufficiently well to allow calculation of rate constants of viscosity increases for both reactions, and, hence, allow development of an Arrhenius temperature relationship. Finally, it is hoped that the proposed equation will provide reasonable estimates of rates of oxidative aging of asphalts at pavement temperatures from short-term, high-temperature oxidative aging data measured in a laboratory.

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Degradative Studies Related to the Plasticity Retention Index of the Standard Malasian Rubber Scheme. I. Kinetics of Degradation

Rubber Chemistry and Technology ◽

10.5254/1.3535865 ◽

1982 ◽

Vol 55 (1) ◽

pp. 181-190 ◽

Cited By ~ 8

Author(s):

Manjit S. Sambhi

Keyword(s):

High Temperature ◽

Oxidative Degradation ◽

Order Rate Constant ◽

Main Process ◽

Oxidative Aging ◽

First Order ◽

First Order Kinetics ◽

Accelerated Storage ◽

Kinetics Of Degradation ◽

Kinetics Of

Abstract Molecular degradation is the main process occurring during the high temperature oxidative aging of most commercial grades of natural rubber. The degradation as measured in terms of Wallace plasticities exhibit first-order kinetics for about 50% extent of degradation. PRI can now be expressed in terms of the first-order rate constant of degradation and is independent of the initial plasticity of the rubber. The observed first-order behavior has been explained in terms of linear intrinsic viscosities versus Wallace plasticities. PRI can be interpreted in terms of the molecular chain length. Complications can, however, arise if hardening of the rubber can occur concurrently with degradation during the PRI test. We then obtain inflated PRI values which overestimate the abilities of the rubbers to resist molecular breakdown, if PRI is considered to arise from degradation only. Perhaps, in order to nullify any possible hardening contribution to PRI values, the PRI test could be designed for rubbers which have undergone some form of controlled accelerated storage-hardening in a manner that prohibits oxidative degradation.

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The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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The influence of high temperature plastic deformation on the kinetics of graphitization of pyrolytic carbons

Journal de Chimie Physique ◽

10.1051/jcp/196966s1121 ◽

1969 ◽

Vol 66 ◽

pp. 121-128 ◽

Cited By ~ 4

Author(s):

D. B. Fischbach

Keyword(s):

Plastic Deformation ◽

High Temperature ◽

Kinetics Of

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Persistent Photoconductivity And Thermal Recovery Kinetics Of Low Energy Ar + Bombarded GaAs

MRS Proceedings ◽

10.1557/proc-223-203 ◽

1991 ◽

Vol 223 ◽

Author(s):

A. Vaseashta ◽

L. C. Burton

Keyword(s):

Deep Level Transient Spectroscopy ◽

Deep Level ◽

Thermal Recovery ◽

Low Energy ◽

Persistent Photoconductivity ◽

Transport Parameters ◽

Excellent Correlation ◽

Proposed Model ◽

Transient Spectroscopy ◽

Kinetics Of

ABSTRACTKinetics of persistent photoconductivity, photoquenching, and thermal and optical recovery observed in low energy Ar+ bombarded on (100) GaAs surfaces have been investigated. Rate and transport equations for these processes were derived and simulated employing transport parameters, trap locations and densities determined by deep level transient spectroscopy. Excellent correlation was obtained between the results of preliminary simulation and the experimentally observed values. The exponential decay of persistent photoconductivity response curve was determined to be due to metastable electron traps with longer lifetime and is consistent with an earlier proposed model.

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ON THE KINETICS OF A RELAXING HIGH TEMPERATURE ATMOSPHERIC PRESSURE NITROGEN PLASMA

High Temperature Material Processes An International Quarterly of High-Technology Plasma Processes ◽

10.1615/hightempmatproc.v8.i4.60 ◽

2004 ◽

Vol 8 (4) ◽

pp. 563-573 ◽

Cited By ~ 1

Author(s):

A. A. Belevtsev ◽

V.F. Chinnov ◽

A.V. Fyodorov ◽

E. Kh. Isakaev ◽

O. A. Sinkevich

Keyword(s):

High Temperature ◽

Atmospheric Pressure ◽

Nitrogen Plasma ◽

Kinetics Of

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POTOMAC

Alloy Digest ◽

10.31399/asm.ad.ts0290 ◽

1975 ◽

Vol 24 (8) ◽

Keyword(s):

Fracture Toughness ◽

High Temperature ◽

Heat Treating ◽

General Purpose ◽

Low Carbon ◽

Repeated Heating ◽

Temperature Changes ◽

Heating And Cooling ◽

Temperature Performance ◽

Heat Checking

Abstract POTOMAC is a general-purpose, low-carbon, chromium-molybdenum-tungsten hot-work steel. It has excellent resistance to shock and heat checking after repeated heating and cooling. Potomac is suitable for hot-work applications involving severe conditions of shock and sudden temperature changes. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-290. Producer or source: Allegheny Ludlum Corporation.

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Modeling of unforced demand response programs

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2020-0208 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Hassan Jalili ◽

Pierluigi Siano

Keyword(s):

Demand Response ◽

Load Shifting ◽

Response Models ◽

Temperature Changes ◽

Proposed Model ◽

Equipment Failures ◽

Demand Response Programs ◽

Simultaneous Implementation ◽

Long Term Studies

Abstract Demand response programs are useful options in reducing electricity price, congestion relief, load shifting, peak clipping, valley filling and resource adequacy from the system operator’s viewpoint. For this purpose, many models of these programs have been developed. However, the availability of these resources has not been properly modeled in demand response models making them not practical for long-term studies such as in the resource adequacy problem where considering the providers’ responding uncertainties is necessary for long-term studies. In this paper, a model considering providers’ unavailability for unforced demand response programs has been developed. Temperature changes, equipment failures, simultaneous implementation of demand side management resources, popular TV programs and family visits are the main reasons that may affect the availability of the demand response providers to fulfill their commitments. The effectiveness of the proposed model has been demonstrated by numerical simulation.

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Usage of the Pareto Fronts as a Tool to Select Data in the Forecasting Process—A Short-Term Electric Energy Demand Forecasting Case

Energies ◽

10.3390/en14113204 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3204

Author(s):

Michał Sabat ◽

Dariusz Baczyński

Keyword(s):

Energy Demand ◽

Demand Forecasting ◽

Electric Energy ◽

Forecasting Model ◽

Short Term ◽

Complex Evaluation ◽

Proposed Model ◽

Energy Demand Forecasting ◽

Pareto Fronts ◽

Naive Approach

Transmission, distribution, and micro-grid system operators are struggling with the increasing number of renewables and the changing nature of energy demand. This necessitates the use of prognostic methods based on ever shorter time series. This study depicted an attempt to develop an appropriate method by introducing a novel forecasting model based on the idea to use the Pareto fronts as a tool to select data in the forecasting process. The proposed model was implemented to forecast short-term electric energy demand in Poland using historical hourly demand values from Polish TSO. The study rather intended on implementing the range of different approaches—scenarios of Pareto fronts usage than on a complex evaluation of the obtained results. However, performance of proposed models was compared with a few benchmark forecasting models, including naïve approach, SARIMAX, kNN, and regression. For two scenarios, it has outperformed all other models by minimum 7.7%.

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