Mixed mode stress intensity factors for semielliptical surface cracks

The three-dimensional equations of elasticity are solved for a flat elliptical crack which has nonuniform shear stresses applied to its surfaces. An alternating method is used to determine the mode two and mode three stress intensity factors for a semielliptical surface crack in the surface of a finite thickness solid. These stress intensity factors are presented as a function of position along the crack border for a number of crack shapes and crack depths. This same technique is followed to determine the mode one stress intensity factors for the semielliptical surface crack which has normal loading applied to its surface. Mode one stress intensity factors are presented and compared with the results obtained from previous work

The power application vacuum switch

Vacuum switching, which has attracted considerable attention recently in the public utility field, is actually far from a new concept. Much of the work done over the past 35 years in the development of the vacuum switch is reviewed

Professional engineering in California

In popular usage, the word “engineer” has come to include many men who are merely technicians or mechanics. In order to set a professional standard for engineers, many states now have passed registration laws defining the qualifications of a Professional Engineer. This article describes the provisions for registration in the State of California

The economic status of the engineer

This is not a committee report, though perhaps it could be made to serve as such, because its genesis was a request from the committee on the economic status of the engineer that a paper be written around the author's remark, “The economic status of the engineer is largely a matter determined by each individual engineer according to his particular personal qualifications and the relations these bear to the work he does and to the personalities of those persons with whom and by whom he is employed.

Effect of resonance decays on hadron elliptic flows

The influence of resonance decays on the elliptic flows of stable hadrons is studied in the quark coalescence model. Although difference between the elliptic flow of pions from resonance decays, except the rho meson, and that of directly produced pions is appreciable, those for other stable hadrons are small. Since there are more pions from the decays of rho mesons than from other resonances, including resonance decays can only account partially the deviation of final pion elliptic flow from the observed scaling of hadron elliptic flows, i.e., the hadron elliptic flow per quark is the same at same transverse momentum per quark. The remaining deviation can be explained by including the effect due to the quark momentum distribution inside hadrons.Comment: 13 pages and 5 figures, version pubblished in PRC, updated references and figure

The sparkless sphere Gap voltmeter - II

Further study of the method of measuring voltages by the force between spheres is reported in this paper, comparison being made of results obtained by means of 100 centimeter spheres with those obtained by other investigators and by a proposed∗ new A.I.E.E. standard for 50 centimeter spheres

Kinetic percolation

Citation: Heinson, W. R., Chakrabarti, A., & Sorensen, C. M. (2017). Kinetic percolation. Physical Review E, 95(5), 6. doi:10.1103/PhysRevE.95.052109We demonstrate that kinetic aggregation forms superaggregates that have structures identical to static percolation aggregates, and these superaggregates appear as a separate phase in the size distribution. Diffusion limited cluster-cluster aggregation (DLCA) simulations were performed to yield fractal aggregates with a fractal dimension of 1.8 and superaggregates with a fractal dimension of D = 2.5 composed of these DLCA supermonomers. When properly normalized to account for the DLCA fractal nature of their supermonomers, these superaggregates have the exact same monomer packing fraction, scaling law prefactor, and scaling law exponent (the fractal dimension) as percolation aggregates; these are necessary and sufficient conditions for same structure. The size distribution remains monomodal until these superaggregates form to alter the distribution. Thus the static percolation and the kinetic descriptions of gelation are now unified

The economic status of the engineer

This is not a committee report, though perhaps it could be made to serve as such, because its genesis was a request from the committee on the economic status of the engineer that a paper be written around the author's remark, “The economic status of the engineer is largely a matter determined by each individual engineer according to his particular personal qualifications and the relations these bear to the work he does and to the personalities of those persons with whom and by whom he is employed.