Secondary Laws Research Articles

A numerical study of parameters controlling stress redistribution in circular notched specimens during creep

In this study, numerical calculations of the creep behaviour of circular notched specimens have been performed with emphasis placed on the role of specimen geometry, material ductility, and the constitutive creep law used for the calculations. In a first order approximation, the calculations performed using primary, secondary, and tertiary-types of constitutive equations result in similar stress distributions for most of the creep life. Therefore, acceptable engineering creep calculations can be performed using a pure Norton-type of constitutive law. In the beginning of creep life, however, there are signifiant differences in calculated stress distributions obtained using primary, secondary, and teriary constitutive laws. Brittle material undergoing primary creep can redistribute stresses faster than a ductile material exhibiting tetriary dominated creep behaviour. Comparing flat plate and cylindrical circular notched specimens it is found that maximum axial stresses are higher for flat plate specimens than for cylindrical specimens. Implications of these results on possible failure mechanisms are discussed.

The influence of safety belt laws on self- reported safety belt use in the United States

We assessed rates and trends in safety belt use by presence and type of safety belt law using data from states participating in the 1984–1989 Behavioral Risk Factor Surveillance System. State(s) with a safety belt law allowing law enforcement officers to stop vehicles for occupants' failure to use safety belts (primary enforcement law) had greater and more rapid increases in safety belt use rates than did states with laws requiring that vehicles must first be stopped for some other violation before a citation or fine for occupants' failure to use safety belts could be imposed (secondary enforcement law). Larger and sustained increases in safety belt use occurred when safety belt laws became effective or when fines were imposed for violations than when laws were first enacted. These data suggest that primary enforcement laws result in greater and more rapid increases in safety belt use than do secondary enforcement laws, and that initial increases in safety belt use following implementation of laws are sustained.

Increasing safety belt use in a secondary enforcement state: evaluation of a three-county special enforcement program

Special enforcement programs to increase belt use present a unique challenge in states with secondary enforcement laws. This paper reports findings from an evaluation of a combined public information and education/enforcement program to increase restraint use along a highly traveled corridor in three Michigan counties. This program (US-31 SAVE) was successful in increasing belt use at least temporarily along the special enforcement corridor. Observed belt use increased from a baseline rate of 56.7% to 65.1% during the program before slipping slightly to 62.7% after the intensive enforcement and PI&E declined (all differences significant at p < .05). This paper details program and evaluation activities and suggests future research needs to better understand the most effective mix of public information and enforcement efforts in states with secondary belt use laws.

Do front-seat belt laws put rear-seat passengers at risk?

Cross-sectional economic models of traffic fatalities are estimated to determine the effectiveness of state statutes that require motor vehicle occupants to use seat belts. The estimates provide some support for the theory of offsetting consumer behavior. In the case of primary enforcement front-seat belt laws, models suggest that rear-seat passengers and nonoccupants may be killed as a result of more dangerous driving by belted drivers. In the case of secondary enforcement front-seat belt laws, there is no favorable or unfavorable effect that is statistically significant. Models that employ self-reported seat belt usage rates from the Centers for Disease Control suggest an offsetting effect for rear-seat passengers and non-occupants as in the case of the models for primary seat belt laws.1

Continuous energy adjoint Monte Carlo

In some applications looking in the adjoint mode is heavily favoured over the forward calculation. Shielding work in which a large source is directing particles at a small target is one such application for example. The paper addresses the problem of forming the transpose of the secondary energy laws including the treatment of S( α, β) for thermalisation adjoint problems.

Deformation Bounds for Bodies in a State of Creep

Bounds on the energy dissipation and surface displacements are found for bodies undergoing nonlinear creep as a result of step loading. Elastic effects are included in a simple manner, and it is shown that the results are applicable to a variety of generalizations of the primary and secondary creep laws.

Lecture demonstration: 2. a procedure for demonstrating the secondary laws of association.

Lecture demonstration: 2. a procedure for demonstrating the secondary laws of association.

Short circuits of alternating-current generators

V. Karapetoff: We may say, with fair assurance, that the problem of short circuits in synchronous machinery, and for that matter, in induction machines, will be with us for some time to come. The means so far used for representing these phenomena have been either cumbersome or insufficient, and I believe it is time for us to decide that in the question of short-circuits we ought to go back to the very fundamental physical facts. Let us begin our treatment not with some secondary laws, such as were admirably presented here, but with primary laws in the existence of which we have not a shade of doubt.