293,559 research outputs found

    Technique for analyzing human respiratory process

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    Electronic system /MIRACLE 2/ places frequency and gas flow rate of the respiratory process within a common frame of reference to render them comparable and compatible with ''real clock time.'' Numerous measurements are accomplished accurately on a strict one-minute half-minute, breath-by-breath, or other period basis

    Respiratory analysis system and method

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    A system is described for monitoring the respiratory process in which the gas flow rate and the frequency of respiration and expiration cycles can be determined on a real time basis. A face mask is provided with one-way inlet and outlet valves where the gas flow is through independent flowmeters and through a mass spectrometer. The opening and closing of a valve operates an electrical switch, and the combination of the two switches produces a low frequency electrical signal of the respiratory inhalation and exhalation cycles. During the time a switch is operated, the corresponsing flowmeter produces electric pulses representative of the flow rate; the electrical pulses being at a higher frequency than that of the breathing cycle and combined with the low frequency signal. The high frequency pulses are supplied to conventional analyzer computer which also receives temperature and pressure inputs and computes mass flow rate and totalized mass flow of gas. From the mass spectrometer, components of the gas are separately computed as to flow rate. The electrical switches cause operation of up-down inputs of a reversible counter. The respective up and down cycles can be individually monitored and combined for various respiratory measurements

    The long-term optical behavior of MRK421

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    All data available in B band for the BL Lac object MRK421 from 22 publications are used to construct a historical light curve, dating back to 1900. It is found that the light curve is very complicated and consists of a set of outbursts with very large duration. The brightness of MRK421 varies from 11.6 magnitude to more than 16 magnitude. Analyses with Jurkevich method of computing period of cyclic phenomena reveal in the light curve two kinds of behaviors. The first one is non-periodic with rapid, violent variations in intensity on time scales of hours to days. The second one is periodic with a possible period of 23.1±1.123.1\pm 1.1 years. Another possible period of 15.3±0.715.3\pm 0.7 years is not very significant. We have tested the robustness of the Jurkevich method. The period of about one year found in the light curves of MRK421 and of other objects is a spurious period due to the method and the observing window. We try to explain the period of 23.1±1.123.1 \pm1.1 years under the thermal instability of a slim accretion disk around a massive black hole of mass of 2106M2 *10^6 M_\odot.Comment: Tex, 14 pages, 5 Postscript figures. Accepted for publication in A&A Supplement Serie

    X-shaped radio galaxies as observational evidence for the interaction of supermassive binary black holes and accretion disk at pc scale

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    A supermassive black hole binary may form during galaxy mergering. we investigate the interaction of the supermassive binary black holes (SMBBHs) and an accretion disk and show that the detected X-shaped structure in some FRII radio galaxies may be due to the interaction-realignment of inclined binary and accretion disk occurred within the pc scale of the galaxy center. We compare in detail the model and observations and show that the configuration is consistent very well with the observations of X-shaped radio sources. X-shaped radio feature form only in FRII radio sources due to the strong interaction between the binary and a standard disk, while the absence of X-shaped FRI radio galaxies is due to that the interaction between the binary and the radiatively inefficient accretion flow in FRI radio sources is negligible. It is suggested that the binary would keep misaligned with the outer disk for most of the life time of FRII radio galaxies and the orientation of jet in most FRII radio galaxies distributes randomly, while the jets in most FRI radio galaxies is expected to be vertical to the accretion disk and thus the major axis of host galaxy. We discuss the relationship of X-shaped and double-double radio galaxies (DDRGs). The model is applied in paticular to two X-shaped radio sources 4C+01.30 and 3C293 and one DDRG source J0116-473 and show that the SMBBHs in the three objects have black hole mass ratios q0.10.3q \sim 0.1 - 0.3.Comment: 35 pages, no figure, no table. Accepted for publication in MNRA