Radon in earthquake prediction research

The observation of anomalies in the radon concentration in soil gas and ground water before earthquakes initiated systematic investigations on earthquake precursor phenomena. The question what is needed for a meaningful earthquake prediction as well as what types of precursory effects can be expected is shortly discussed. The basic ideas of the dilatancy theory are presented which in principle can explain the occurrence of earthquake forerunners. The reasons for radon anomalies in soil gas and in ground water are clarified and a possible classification of radon anomalies is given.     

Physical and conduction measurements of spin-on oxide

Spin-on oxide refers to a thin film of silicon dioxide deposited from an alcohol solution to the surface of a semiconductor wafer by spinning. An investigation was carried out by IR spectroscopy, gravimetric analysis and etch-rate measurements. Electrical conduction in the oxide was also examined. It was found that the oxide is hygroscopic and that the breakdown properties are generally inferior to those of thermally grown oxide, particularly if the samples are annealed at a low temperature only. Attempts were also made to identify the mechanisms responsible for conduction in the oxide.     

Physical property measurements for the mathematical modeling of fluid flow in solidification processes

Measurement methods are being developed to provide values for the density, viscosity, heat capacity, enthalpy, fraction solid, surface tension, and thermal diffusivity and conductivity of commercial alloys in the liquid and mushy states. These data are needed for the mathematical modeling of heat and fluid flow in solidification processes. This paper briefly describes the present state of development of apparatus for the measurement of density by the levitated drop and hydrostatic probe methods and viscosity by the oscillating viscometer in our laboratory. Paper presented at the Fourth Asian Thermophysical Properties Conference, September 5–8, 1995, Tokyo, Japan.     

Atmospheric optical turbulence over land in middle east coastal environments: prediction modeling and measurements

Beam intensity scintillations, characterized by a refractive-index structure parameter and caused by variations of macrometeorological features of the coastal atmosphere such as air temperature, wind speed and direction, and relative humidity, are examined theoretically and experimentally. In our theoretical analysis we present two well-known models considered separately for over-water and over-land atmospheric optical communication or imaging channels. By means of comparison with our experiments carried out in midland coastal environments in southern and northern Israel, we show the limitations of the models to predict the refractive-index structure Cn2 parameter for both daytime and nighttime turbulent atmospheres in different coastal zone meteorological conditions. We also present an extension of an existing model with two different practical applications that, as is shown experimentally, can be a good predictor of Cn2 for optical atmospheric paths over midland coastal zones.     

Physical metallurgy and magnetic measurements of SmCo5-SmCu5alloys

The magnetic properties of the hexagonal intermetallic compounds involving the rare-earth and3dtransition metals have been reported in the literature. These alloys look promising as fine-particle permanent magnets. A large number of samples in the system SmCo5-xCuxwere prepared by induction melting under a protective atmosphere, and annealed at various temperatures. An outstanding feature of these alloys is their high intrinsic coercive force. After annealing at low temperatures, they show coercive forces above 20 kOe and an energy product of about 8 × 10⁶G.Oe. The most important factors determining the coercive force appear to be the chemical composition, the cooling rate, the alignment of the SmCO5-rich phase, and the annealing treatment. Examination by electron microscopy and electron probe techniques suggests a spinodal decomposition of a supersaturated solid solution into two phases, one rich in SmCo5and the other rich in SmCu5.     

Planning measurements in certifying methods of performing measurements

A procedure is proposed for planning measurements in certifying a linear measurement method MM, and estimates are made of the adequacy of a linear MM. Translated from Izmeritel’naya Tekhnika, No. 1, pp. 60–69, January, 1998.     

Effect on the partial least-squares prediction of yarn properties combining raman and infrared measurements and applying wavelength selection

The combination of Raman and infrared spectroscopy on the one hand and wavelength selection on the other hand is used to improve the partial least-squares (PLS) prediction of seven selected yarn properties. These properties are important for on-line quality control during production. From 71 yarn samples, the Raman and infrared spectra are measured and reference methods are used to determine the selected properties. Making separate PLS models for all yarn properties using the Raman and infrared spectra, prior to wavelength selection, reveals that Raman spectroscopy outperforms infrared spectroscopy. If wavelength selection is applied, the PLS prediction error decreases and the correlation coefficient increases for all properties. However, a substantial wavelength selection effect is present for the infrared spectra compared to the Raman spectra. For the infrared spectra, wavelength selection results in PLS prediction errors comparable with the prediction performance of the Raman spectra prior to wavelength selection. Concatenating the Raman and infrared spectra does not enhance the PLS prediction performance, not even after wavelength selection. It is concluded that an infrared spectrometer, combined with a wavelength selection procedure, can be used if no (suitable) Raman instrument is available.     

Imaging of earthquake sources

Elastic waves, produced by temporally and spatially finite fault ruptures during earthquakes, propagate through the Earth. Recordings of these waves at the Earth's surface provide the data for reconstruction of the source properties, including location, spatial and temporal extents, and rupture velocities. A 2D finite-difference solution of the elastic wave equation is used to numerically extrapolate synthetic observations backward in time to create images of the energy release during an earthquake.     

Positron measurements in steels

Positron Doppler broadening measurements were utilized to detect changes in trapping mechanisms in steels.     

Windows in ellipsometry measurements

The effect of windows or lenses placed between the polarization-state generator and the polarization-state detector in a general ellipsometry measurement is examined. It is found that three parameters are required for describing the effects of the window retardation on the ellipsometry measurements. Two of these window parameters can be measured at the same time as the sample parameters if the sample is isotropic, but the third window parameter cannot be determined independently and must be measured separately. If the sample is anisotropic, then none of the windows parameters can be measured independently at the same time as the sample parameters. An example is given in which the strain-induced retardation in fused-silica focusing lenses is measured with a two-modulator generalized ellipsometer and the results are used to correct the sample data.     

Thoron measurements in Hungary

In this study, several Hungarian dwellings and working places were surveyed using passive radon- and thoron-measuring devices (Radopot(?) and Raduet(?)) from 2003 to 2008. The detectors were placed 15-30 cm from the wall throughout the 1- to 3-month period. In dwellings, the presence of thoron, ～100 Bq m(-3), was detected almost in all cases, ; however, in the cellars of these buildings, a value ～200 Bq m(-3) was typical. In the cases of manganese and bauxite mines, the concentration of thoron was mainly 200 and 500 Bq m(-3), respectively. In caves, it was 1000 Bq m(-3), whereas in the radon bath it was ～100 Bq m(-3). As in many cases, the ratio between thoron and radon concentrations was >0.25 and the dose contribution from thoron and its progeny was not negligible. Therefore, further investigation on the thoron progeny will be necessary for an accurate dose estimation.