Showing papers by "Applied Science Private University published in 1986"
TL;DR: In this paper, a two-dimensional study of the influence of deep sediment on seismic ground motions was conducted by recording and analyzing long-period microtremors in the San Fernando Valley, California.
Abstract: A two-dimensional study of the influence of deep sediment on seismic ground motions was conducted by recording and analyzing long-period microtremors in the San Fernando Valley, California. The recordings were made at 50 regularly distributed sites in the valley. Three reference sites were employed at the baserock outcrop around the valley so as to observe the time-dependent characteristics of the microtremors . 1. Amplitudes in a period range of several seconds correlate with the thicknesses of the sedimentary layers . 2. A site amplification effect, which was evaluated in terms of sediment-to-rock spectral ratios, is qualitatively consistent with available geological and strong motion data . 3. The practical field observation procedure designed for this study, the two-dimensional approach, can be easily used in other surveys for estimating the spatial characteristics of earthquake ground motions in the period range of several seconds .
70 citations
TL;DR: How back and spinal movements have been and are being measured (principally the low back and lumbar spine) are examined.
63 citations
52 citations
01 Jan 1986
TL;DR: It is concluded that entrapped cement will damage both components of the prosthesis and may cause premature failure and Laboratory tests show that retrieved acrylic cement particles will scratch stainless steel.
Abstract: A number of polyethylene acetabular cups (59) and femoral stems (38) of Charnley hip prostheses were obtained following revision surgery and examined by scanning electron microscopy. In many cases, acrylic cement particles were embedded in the articulating surface of the cups. These particles caused surface pitting. The appearance of the articulating surfaces suggested that some cement had been present from the time of arthroplasty. In other cups there was evidence of cement ingress during the service life. Failure to use sufficient cement at arthroplasty resulted in cavities on the backs of the cups. Many femoral heads had become scratched in vivo. the surface roughness increasing from an initial value less than 0.02 pm Ra to a value on removal of 0.07 pm Ra. The increased roughness increases the amount of wear in the polyethylene sockets. Laboratory tests show that retrieved acrylic cement particles will scratch stainless steel, and it is our conclusion that entrapped cement will damage both components of the prosthesis and may cause premature failure.
47 citations
TL;DR: Although temperature did not directly affect the response of the ligaments to load, the thermal expansion of the soft tissue elements may have implications for the function and mobility of spinal joints if measured at room rather than body temperature.
39 citations
TL;DR: Fair agreement is found between the experimental absorption spectra and simulations calculated by a hydrodynamic code in this work to diagnose the conditions in the pusher of laser-imploded targets.
Abstract: Absorption spectroscopy has been used in this work to diagnose the conditions in the pusher of laser-imploded targets. Absorption lines are produced when continuum radiation from the hot central compressed gas passes out through the colder surrounding pusher. They can be used to determine both the temperature and the \ensuremath{\rho} \ensuremath{\Delta}R product of the pusher around peak compression. Fair agreement is found between the experimental absorption spectra and simulations calculated by a hydrodynamic code. Applications of this work to the diagnosis of future, high-compression implosions is discussed.
32 citations
TL;DR: In this article, a theory of the production of sound by turbulent boundary layer flow over a rough wall is proposed, where the roughness elements are embedded entirely within the viscous sublayer, and the radiation is determined by estimating the diffraction of the turbulence nearfield by those elements.
29 citations
TL;DR: In this paper, all quadratic, cubic and quartic force constants associated with high and low vibrational modes of H3N⋯HF hydrogen-bonded and LiF lithium-bunded complexes have been calculated employing the Moller-Plesset perturbation theory to the second order (MP2) with the 4-31G* basis set.
14 citations
11 citations
TL;DR: Etude de l'effet de la temperature sur la permittivite et la perte dielectrique a 35 GHz de verres MoO 3 -P 2 O 5.
Abstract: Etude de l'effet de la temperature sur la permittivite et la perte dielectrique a 35 GHz de verres MoO 3 -P 2 O 5
1 citations
TL;DR: In this article, the authors investigated the effect of water content on the compressive load carrying capacity of polyurethane foam for wheelchair cushions and found that these foam cushions became less stiff and exhibited greater than 20% increase in deformation when containing 20% water by volume at loads encountered in seating.
Abstract: The chairbound, disabled person requires a supportive cushion to distribute pressure in order to reduce the risk of pressure sores and any alteration to the load carrying capacity of the cushion may have a deleterious effect on its ability to provide adequate support. The National Health Service supplies two basic grades of polyurethane foam for wheelchair cushions and this study investigated the effect of water content on their compressive load carrying capacity. Both foams became less stiff and exhibited greater than 20% increase in deformation when containing 20% water by volume at loads encountered in seating.This decrease in stiffness may result in a dramatic change in the pressure distribution under a patient particularly if only a small section of the cushion becomes wet.This result emphasizes the need to fit waterproof coverings to these foam cushions and to maintain the integrity of the covering.