Degree Of Weakening Research Articles

Studies on flower longevity in Digitalis

The flowers of Digitalis purpurea respond to pollination by rapid corolla abscission without any loss of corolla turgor, nor any significant loss of corolla constituents, relative to the corollas of unpollinated flowers of a similar age. The corollas of unpollinated flowers too eventually abscise, 6 d after the stigma opens, however, they do so with only a minimal loss of fresh weight or corolla constituents. Pollination causes an increase in ethylene production detectable within 1 h. Increased ethylene production occurs initially only from the upper portion of the style, later from the lower portion, and lastly, between 23 and 48 h after pollination, from the ovary plus calyx. The pollination response can be induced by exogenous ethylene, the degree of weakening of the corolla abscission zone being dependent upon the concentration and duration of the exposure period and on the stage of flower development. The regulation of ethylene biosynthesis and its involvement in the control of pollination-induced corolla abscission are discussed.

The interaction of anthracene with V-III and KBKV synthetic resins, and the possibility of its use as an electronic probe for determination of their adhesive strength

The luminescence spectra of thick and thin coatings of synthetic resins V-III and KBKV, and the inhibitor composition I-5, on iron and steel were recorded for the purpose of studying their adhesive properties by the electronic probe method. It was found that the resins are reactive toward anthracene. The interaction between the resins and anthracene, which at first is of a physical nature, gradually changes to chemical interaction. The physical interaction between the resins and anthracene is weaker in the boundary layer and the degree of weakening is dependent on the strength of contact with the solid body. The adhesive strength is characterized by the displacement of the bands and the ratio of their intensities in the anthracene spectrum. It is shown that it is possible to construct calibration graphs for determination of adhesive strength.

Quantitative characterization of surface damage to WC-cobalt composites by electrochemical grinding

Electrochemical grinding (ECG) of WC-cobalt cemented carbides leads to poor surface quality which can be attributed to the faster electrochemical dissolution velocity into the cobalt phase than into the carbide phase. A method for measuring the degree and depth of damage in the WC-cobalt surface layer, weakened by preferential electrochemical removal of cobalt after ECG, is developed based upon an analysis of the mechanical grinding transient which occurs after switching off the electrical current for ECG. The degree of weakening is expressed as the ratio of the specific grinding energy of the material in the surface layer to the normal specific grinding energy. It is found that surface damage from ECG can reduce the specific grinding energy by as much as a factor of 10 at the finished surface, and that the depth of the damaged layer is shallower with a lower current density and a faster infeed velocity.

An analysis of coseismic tilt changes from an array in central California

location models and are easily identified by coincidence with the earthquake occurrence time. Press [ 1965] reported a strain step of 10 -8 recorded at Kipapa, Oahu, Hawaii, after the magnitude 8.4, 1964 Alaskan earthquake. This particular strain step was of the amplitude expected from the model presented. There were tilt and strain steps associated with other large teleseisms that were orders of magnitude greater than were expected and were suggested to be caused by geologic complexities or instrumental and/or site effects. Wideman and Major [1967] summarize strain step observations for step amplitudes in the range 10-4-10 -o recorded at distances up to 104 km from the source (nuclear as well as seismic) and event magnitudes from 3.0 to 8.5. They determined a strain step amplitude dependence of R-, a = { (R is the epicentral distance). The theoretical analysis by Ben-Menahem et al. [1969] suggests that because the predicted amplitude dependence is quadrupole, not radial, a is in the range I > a > 6, depending upon the source-to-station geometry. McGinley [1968] analyzed anomalously large strain and tilt step data from four earthquakes and suggested that a model of a weak layer in the lower crust or upper mantle could be used to reproduce some features of the observations if the degree of weakening is quite severe. Berg and Lutschak [1973] report tilt steps following local and teleseismic events recorded by the University of Alaska Tripartite Tilt Network that are more than an order of magnitude larger than those expected from Press's [1965] model and tilt step propagation velocities compatible with Rayleigh wave velocities. Although strain steps for the San Fernando earthquake can be fit by a simple half