Observations of Oscillating Cavitation on a Flat Plate Hydrofoil

An experimental investigation was made to clarify the characteristics of oscillating cavitation on a flat plate hydrofoil in a water tunnel. Dynamic the behavior of oscillating cavitation is discussed from the unsteady pressure measurements at the upstream of the blade and the visual observations of cavitation phenomena using high-speed video recording. It was found that the mean cavity length characterizes the fundamental characteristics of cavity oscillation. The cavity oscillations are categorized into two types, i.e. the transitional cavity oscillation and the partial cavity oscillation

Smoothing of Impulse Noise by Orthogonal Transform

Electromagnetic impulse noise which is harmful to signal measurement or transmission of information, is smoothed by the orthogonal transform processor. The idealized impulse noise with infinitesimal duration and Gaussianly-distributed amplitude shows the same spectral characteristics as white Gaussian noise. Optimal correlation detector against such noise is easily realized by the orthogonal transform processor. Photoelectric pulse signals disturbed by the impulse noise from the power supply can be well detected through the Walsh waveform analyzer. Also, orthogonally-synthesized signals can be demodulated with firmly-suppressed impulse noise, where both the statistical and instantaneous SNRs are superior to those in the usual PCM transmission system

The origins of the gamma-ray flux variations of NGC 1275 based on 8 years of Fermi-LAT observations

We present an analysis of 8 years of Fermi-LAT ( > 0.1 GeV) gamma-ray data obtained for the radio galaxy NGC 1275. The gamma-ray flux from NGC 1275 is highly variable on short (~ days to weeks) timescales, and has steadily increased over this 8-year timespan. By examining the changes in its flux and spectral shape in the LAT energy band over the entire dataset, we found that its spectral behavior changed around 2011 February (~ MJD 55600). The gamma-ray spectra at the early times evolve largely at high energies, while the photon indices were unchanged in the latter times despite rather large flux variations. To explain these observations, we suggest that the flux changes in the early times were caused by injection of high-energy electrons into the jet, while later, the gamma-ray flares were caused by a changing Doppler factor owing to variations in the jet Lorentz factor and/or changes in the angle to our line of sight. To demonstrate the viability of these scenarios, we fit the broad-band spectral energy distribution data with a one-zone synchrotron self-Compton (SSC) model for flaring and quiescent intervals before and after 2011 February. To explain the gamma-ray spectral behavior in the context of the SSC model, the maximum electron Lorentz factor would have changed in the early times, while a modest change in the Doppler factor adequately fits the quiescent and flaring state gamma-ray spectra in the later times.Comment: 13 pages, 9 figures; accepted for publication in Ap

A Walsh Waoofonn Analyzer and Its Applications to Filtering of Pulse Signals

A new waveform analyzer based on the Walsh transform　is developed and is applied to a real-time filtering of fast pulse signals, and the linear filterings　of time signals through the Walsh transform is　discussed. The analyzer converts a solitary waveform during 16 μs into the 16 Walsh amplitude spectra in a hybrid manner: it has the sequency band from 62.5 kzps to 500 kzps. The spectra are parallelly held during 16 μs by analog integrators, while serially displayed by the CRT, and one of them is digitally read out. The spectra of the test waves are measured within the error rate of several per cent. The analyzer is applied to the correlative detection of the photoelectric pulse signals in a gasspectroscopic system using a pulse laser, and there composes the matched filter, which is useful for measuring the signals superposed by Gaussian noises with a high accuracy. For the real-time filtering of fast signals, the arithmetic convolution and the frequency power spectra are approximated using the complex Walsh transform. These approximations are of practical use in 16 or 32 dimensions. Then, the matched filters for pulse peaking are given by the approximate convolution and by the dyadic convolution

Feeding Habits of the Tomato Bug, Cyrtopeltis (Engytatus) modestus (Distant), with Special Reference to the Feeding Lesion on Tomato

The present study concerns the feeding habits of the tomato bug, Cyrtopeltis (Engytatus) modestus (Distant), and the unusual feeding lesions produced on tomato plants. Existing information on the feeding habits and the taxonomic status of this insect have been incorporared in this bulletin. During the five-year period of this study, 1940-1945, the tomato bug was a serious pest of tomato in Hawaii and was difficult to control with the insecticides available at that time. At present it is effectively controlled by DDT

Microcomputer Filtering System to Measure Very Small Transmission Loss of Impulsive Signals

This paper describes a method for measuring very small transmission loss of impulsive signals. The correlative fluctuations within input and output signals are eliminated effectively by the analog simultaneous differencer. The difference and normal signals are alternately sampled and accumulated by the digitizer and the microcomputer, that is, the microcomputer 2-channels box-car integrator is realized. The difference and normal accumulated data are transferred to the personal computer, which calculates the ratio of the difference to normal accumulated data, i.e. the estimated attenuation in nepers. By the experiments of electrical and optical impulse transmissions, the minimum measurable attenuations become respectively 2.7×10(-4)NP and 6.0×10(-4)Np. Even the latter value is the smallest so far as the authors know

Processed Rice in Hawaii: Nutritive Value, Susceptibility to Insect Infestation and Consumer Acceptance as Compared with White and Brown Rice

Factors affecting the nutritive value and use of processed rice In Hawaii have been studied. Twenty-two samples of processed rice have been found to have an average thiamine content of 193 micrograms per 100 grams. Processed rice has higher thiamine, niacin, calcium, phosphorus, and iron contents than does white rice, but has lower thiamine and iron contents than does brown rice. Processed rice has a lower moisture content than brown or white. During 16 weeks of storage in two Honolulu warehouses, processed rice was found to have slightly less insect infestation than white rice and much less than brown rice. During storage, the processed rice lost 17 percent of its thiamine content; brown rice lost 33 percent, and white rice 34 percent. Losses of niacin were less than those of thiamine - approximately 15 percent of the niacin content of all the rices. The same rices stored 18 months under laboratory conditions also decreased in thiamine content. Processed rice lost 34 percent, brown rice 38 percent, and white rice 15 percent. The thiamine of processed rice has been shown to be available to human beings by studies of the thiamine excretion of human subjects on a diet containing 375 grams of rice, raw weight, daily. Washing processed rice seven times removes 22 percent of the thiamine and about 50 percent of the minerals. Washed processed rice contains an insignificant percentage of the daily requirement for calcium, phosphorus, and iron. Brown rice retains its nutrients better during washing than either white or processed. Losses of thiamine in cooking processed rice vary according to the method used from 18 to 54 percent. Discarding the cooking water results in large losses of thiamine. Brown and white rice cooked in small amounts of water lose 18 and 9 percent of their thiamine content. A study of plate waste in school cafeterias indicates that processed rice is eaten readily by customers of such cafeterias. Interviews with 200 Honolulu families who tried the rice indicate that 12 percent of them prefer processed or mixed processed and white to other kinds of rice. It may be concluded from these studies that processed rice stores as well as or better than white rice and has a higher nutritive value. It is lower in nutritive value than brown rice but is not as subject to insect infestation and deterioration

Response of Electromagnetic Deflection for CRT Display

In the CRT display system of high-speed electromagnetic deflection, the tendency to amplifier saturation should not be neglected. We first show the limitation to the linear characteristics of input-output response and the response time under the saturation condition in this system. We try to improve the frequency-characteristics of the amplifier by making the load resistance constant and the feedback-paths partially positive, and reduce the L/R value of the load circuit by adopting the mutually-coupled yokecoils and the low-current amplifier. As the result, it is suggested that a low-power dissipation and highspeed response electromagnetic deflection system can be constructed

A Notion of Adjoint Spectrum in the Application to Air-pollution Monitoring

This report deals with a notion of adjoint spectrum which is applicable to air-pollution monitoring by using pulsed lasers. Both Raman and absorption spectra of multiple gas complex are linear combinations of the spectra, each of which is specific to a gas species and its magnitude is proportional to the density. An extended formulation of the method of least squares is made in terms of a new notion, adjoint spectra, which visualizes the structure of the numerical filter. Applications of the derived numerical filters to the two methods are shown and features are described about the synthesized filters