363 research outputs found
The Design, Construction, and Performance of a Magnetic Focusing, Semi-Circular, Low Energy Beta-Ray Spectrometer
A semi-circular beta-ray spectrometer (Fig. 1) has been constructed
for operation between 2 and 120 kev electron energy. This
instrument was designed to supplement the ring- focusing beta-ray spectrometer
whose lower limit is approximately 25 kev. The 180°
spectrometer has an electron trajectory radius of 12 cm. The field is
produced by two iron free coils spaced to give a nearly homogeneous
field (with some second order focusing) in the region of the electron
trajectories . The field current is supplied by a one kw motor- generator
set. Stabilization is obtained to 2 parts in 10, 000 with a rotating electro- mechanical unit and an electronic servo system. Source and
Geiger counter window dimensions for a standard resolution of 0 .8% are 0.1 cm x 4 cm. With a 10 Ό.g/cm^2 formvar window, transmission is assured
down to 2 kev electron energy. A recording potentiometer traces the
counting rate vs. electron energy. Several examples of chart recordings
are reproduced to illustrate the performance of the semi- circular beta-ray
spectrometer
The Fundamental Constants of Physics, Vol. 1 of Interscience Monographs in Physics & Astronomy [book review]
Book review of: The Fundamental Constants of Physics. Vol. 1 of
Interscience Monographs in Physics & Astronomy. By
E. Richard Cohen, Kenneth M. Crowe, Jesse W. M.
DuMond. 287 pp. Interscience Publishers, Inc., New
York, 1957.
Reviewed by H. Mendlowitz, National
Bureau of Standards
A Determination of the Wave Forms and Laws of Propagation and Dissipation of Ballistic Shock Waves
Experiments to ascertain the wave forms and laws of propagation and dissipation of ballistic shock waves to large distances (80 yards) from the bullet trajectory are described. Calibers 0.30, 0.50, 20 mm, and 40 mm were studied. In every case an Nâshaped wave profile was observed consisting of a sudden rise in pressure, the âhead discontinuity,â followed by an approximately linear decline to a pressure about equally far below atmospheric and then a second sudden return, the âtail discontinuity,â to atmospheric pressure. The peak amplitudes of this disturbance are found to diminish about as the inverse 3/4 power of the missâdistance (perpendicular distance from the trajectory) while the period TâČ (measured between the discontinuous fronts) increases about as the 1/4 power of the missâdistance for calibers 0.30, 0.50, and 20 mm. For 40âmm shells the amplitude decays a little faster, about as the inverse 0.9 power of missâdistance over the range studied. A theory taking account of the dissipation of the Nâwave energy into heat is developed to explain the observed behavior. A method of measuring absolute Nâwave amplitudes by observing the rate of change of period TâČ with propagation is described. The theory leads to an absolute relationship at large distances between distance, amplitude, and period in which no arbitrary constants appear
Staff Perceptions of Risk for Prison Rape Perpetration and Victimization
Copyright © 2012 SAGE Publications, http://tpj.sagepub.com Used by permission
Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action
Background Patterns of food intake and prevalent osteoarthritis of the hand, hip, and knee were studied using the twin design to limit the effect of confounding factors. Compounds found in associated food groups were further studied in vitro. Methods Cross-sectional study conducted in a large population-based volunteer cohort of twins. Food intake was evaluated using the Food Frequency Questionnaire; OA was determined using plain radiographs. Analyses were adjusted for age, BMI and physical activity. Subsequent in vitro studies examined the effects of allium-derived compounds on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells. Results Data were available, depending on phenotype, for 654-1082 of 1086 female twins (median age 58.9 years; range 46-77). Trends in dietary analysis revealed a specific pattern of dietary intake, that high in fruit and vegetables, showed an inverse association with hip OA (p = 0.022). Consumption of 'non-citrus fruit' (p = 0.015) and 'alliums' (p = 0.029) had the strongest protective effect. Alliums contain diallyl disulphide which was shown to abrogate cytokine-induced matrix metalloproteinase expression. Conclusions Studies of diet are notorious for their confounding by lifestyle effects. While taking account of BMI, the data show an independent effect of a diet high in fruit and vegetables, suggesting it to be protective against radiographic hip OA. Furthermore, diallyl disulphide, a compound found in garlic and other alliums, represses the expression of matrix-degrading proteases in chondrocyte-like cells, providing a potential mechanism of action
Internally Electrodynamic Particle Model: Its Experimental Basis and Its Predictions
The internally electrodynamic (IED) particle model was derived based on
overall experimental observations, with the IED process itself being built
directly on three experimental facts, a) electric charges present with all
material particles, b) an accelerated charge generates electromagnetic waves
according to Maxwell's equations and Planck energy equation and c) source
motion produces Doppler effect. A set of well-known basic particle equations
and properties become predictable based on first principles solutions for the
IED process; several key solutions achieved are outlined, including the de
Broglie phase wave, de Broglie relations, Schr\"odinger equation, mass,
Einstein mass-energy relation, Newton's law of gravity, single particle self
interference, and electromagnetic radiation and absorption; these equations and
properties have long been broadly experimentally validated or demonstrated. A
specific solution also predicts the Doebner-Goldin equation which emerges to
represent a form of long-sought quantum wave equation including gravity. A
critical review of the key experiments is given which suggests that the IED
process underlies the basic particle equations and properties not just
sufficiently but also necessarily.Comment: Presentation at the 27th Int Colloq on Group Theo Meth in Phys, 200
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