scholarly journals Multi-wavelength photometry during the 2018 superoutburst of the WZ Sge-type dwarf nova EG Cancri

2020 ◽  
Author(s):  
Mariko Kimura ◽  
Keisuke Isogai ◽  
Taichi Kato ◽  
Naoto Kojiguchi ◽  
Yasuyuki Wakamatsu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Late Stage ◽  
Mass Ratio ◽  
Optical Photometry ◽  
Dwarf Nova ◽  
Upper Limit ◽  
Disk Mass ◽  
Multi Wavelength ◽  
The Difference ◽  
Optical Flux

Abstract We report on the multi-wavelength photometry of the 2018 superoutburst in EG Cnc. We have detected stage A superhumps and long-lasting late-stage superhumps via the optical photometry and have constrained the binary mass ratio and its possible range. The median value of the mass ratio is 0.048 and the upper limit is 0.057, which still implies that EG Cnc is one of the possible candidates for period bouncers. This object also showed multiple rebrightenings in this superoutburst which are the same as those in its previous superoutburst in 1996–1997, despite the difference in the main superoutburst. This would represent that the rebrightening type is inherent to each object and is independent of the initial disk mass at the beginning of superoutbursts. We also found that B − I and J − Ks colors were unusually red just before the rebrightening phase and became bluer during the quiescence between rebrightenings, which would mean that the low-temperature mass reservoir at the outermost disk accreted with time after the main superoutburst. Also, the ultraviolet flux was sensitive to rebrightenings as well as the optical flux, and the U − B color became redder during the rebrightening phase, which would indicate that the inner disk became cooler when this object repeated rebrightenings. Our results thus basically support the idea that the cool mass reservoir in the outermost disk is responsible for rebrightenings.

scholarly journals First detection of two superoutbursts during the rebrightening phase of a WZ Sge-type dwarf nova: TCP J21040470+4631129

2020 ◽  
Vol 72 (3) ◽  
Author(s):  
Yusuke Tampo ◽  
Kojiguchi Naoto ◽  
Keisuke Isogai ◽  
Taichi Kato ◽  
Mariko Kimura ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Accretion Disk ◽  
Late Stage ◽  
Large Radius ◽  
Mass Ratio ◽  
Dwarf Novae ◽  
Dwarf Nova ◽  
Spectroscopic Observations ◽  
The Third ◽  
Photometric And Spectroscopic Observations

Abstract We report on photometric and spectroscopic observations and analysis of the 2019 superoutburst of TCP J21040470+4631129. This object showed a 9 mag superoutburst with early superhumps and ordinary superhumps, which are the features of WZ Sge-type dwarf novae. Five rebrightenings were observed after the main superoutburst. The spectra during the post-superoutburst stage showed Balmer, He i, and possible sodium doublet features. The mass ratio is derived as 0.0880(9) from the period of the superhump. During the third and fifth rebrightenings, growing superhumps and superoutbursts were observed, which have never been detected during a rebrightening phase among WZ Sge-type dwarf novae with multiple rebrightenings. To induce a superoutburst during the brightening phase, the accretion disk needs to have expanded beyond the 3 : 1 resonance radius of the system again after the main superoutburst. These peculiar phenomena can be explained by the enhanced viscosity and large radius of the accretion disk suggested by the higher luminosity and the presence of late-stage superhumps during the post-superoutburst stage, plus by more mass supply from the cool mass reservoir and/or from the secondary because of the enhanced mass transfer than those of other WZ Sge-type dwarf novae.

scholarly journals 2. On the Polarizability of Heat from different Sources

1845 ◽  
Vol 1 ◽  
pp. 334-334
Author(s):  
Forbes
Keyword(s):  
Low Temperature ◽  
The Difference ◽  
Different Sources

The author of this paper states in it his belief, that the curious fact formerly announced to the Society of the greater permeability of mica, laminated by heat, to heat of low temperature, contrary to the usual character of the same substance (a property which he has since extended (see Proceedings, Jan. 1840) to changes of mechanical conditions of surface), may very probably explain, as M. Melloni anticipates, the difference in point of fact long contested between them as to the equal or unequal polarizability of heat from different sources.

Simultaneous infrared and optical photometry of the Eclipsing Dwarf Nova V2051 Ophiuchi

1986 ◽  
Vol 6 (3) ◽  
pp. 306-308 ◽  
Author(s):  
D. J. Watts ◽  
R. D. Watson
Keyword(s):  
Light Curve ◽  
Optical Photometry ◽  
Dwarf Nova

AbstractA complete orbital light-curve of V2051 Oph in the IR H band is presented, together with a second eclipse in the J band. Simultaneous Rc band data were obtained. Eclipse depths in Rc, J and H are 1.8 mag, 1.0 mag and 0.8 mag respectively. No evidence for ellipsoidal variations due to the secondary was seen and constraints on the secondary are discussed.

scholarly journals IMMOBILIZATION OF Saccharomycess cereviceae BIOMASS ON CHITOSAN AND ITS APPLICATION AS AN ADSORBENT FOR Pb(II) ION

2011 ◽  
Vol 11 (2) ◽  
pp. 174-179 ◽  
Author(s):  
Hasri Hasri ◽  
Mudasir Mudasir ◽  
Nurul Hidayat Aprilita ◽  
Roto Roto
Keyword(s):  
Optimum Condition ◽  
Functional Groups ◽  
Contact Time ◽  
Metal Ion ◽  
Mass Ratio ◽  
Adsorption Experiment ◽  
Ion Removal ◽  
Before And After ◽  
The Difference

An application of Saccharomycess cereviceae biomass immobilized on chitosan (SC-Chi adsorbent) for Pb(II) ion removal was demonstrated. Adsorption experiment was conducted at various mass ratio of Saccharomycess cereviceae biomass to chitosan, contact time, pH of solution and concentration of cation. Total Pb(II) metal ion adsorbed was calculated from the difference of the amount of metal ion before and after adsorption which was measured by AAS. The results showed that optimum condition for adsorption of Pb(II) ion by the SC-Chi was achieved using mass ratio of Saccharomycess cereviceae to chitosan of 50% (w/w), pH solution of 7, contact time of 60 min and concentration of 25 mgL-1. The hydroxyl (-OH) and amino (-NH2) functional groups are believed to be responsible for the adsorption of Pb(II) ion by the adsorbent.

scholarly journals Identification of factors affecting competitive tension in the domestic air transport market in Turkey

2020 ◽  
Vol 56 (2) ◽  
pp. 118-139
Author(s):  
Mehmet Yasar ◽  
Ender Gerede
Keyword(s):  
Market Concentration ◽  
Air Transport ◽  
Competitive Market ◽  
Regression Analyses ◽  
Factors Affecting ◽  
Upper Limit ◽  
Competitor Analysis ◽  
Competitive Action ◽  
Different Dimensions ◽  
The Difference

AbstractCompetitive tension refers to pressure that is considered to exist among firms operating in a competitive market and that forces them to take competitive action against each other. An imaginary upper limit of competitive tension symbolizes the difference between whether to take competitive action or not. The antecedents of competitive tension are examined in this study. Within this scope, market commonality and resource similarity are the variables studied as components of competitor analysis; market concentration that provides clues for the competitive structure of competed markets; and finally, competitive asymmetry, presuming that the competition among the companies is not equal and rivals do not consider each other at the same level as competing firms, were taken as primary variables of competitive tension. In order to test whether these variables have an effect on competitive tension among airlines, airlines operating in the domestic air transport market in Turkey were examined in this study. The perceived competitive tension that was detected as a result of regression analyses was studied on three different dimensions, namely, internal tension, external tension, and total tension, and each dimension was analyzed as a different model. The findings of the study revealed that market commonality and market concentration have a significant effect on competitive tension. These effects were found to be positive for market commonality and negative for market concentration. Resource similarity and competitive asymmetry were found to have no significant effect.

scholarly journals Responses of leaf traits to low temperature in an evergreen oak at its upper limit

2020 ◽  
Vol 35 (5) ◽  
pp. 900-911
Author(s):  
Xi Jin Zhang ◽  
Kun Song ◽  
Ying Ji Pan ◽  
Zhi Wen Gao ◽  
Fa Guang Pu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Leaf Traits ◽  
Upper Limit ◽  
Evergreen Oak

scholarly journals Late pregnancy analysis with Yunban’s remote fetal monitoring system

2019 ◽  
Vol 15 (3) ◽  
pp. 155014771983283
Author(s):  
Qiuping Wang ◽  
Weihua Yang ◽  
Lie Li ◽  
Guokai Yan ◽  
Huihui Wang ◽  
...  
Keyword(s):  
Late Stage ◽  
Stress Test ◽  
Fetal Monitoring ◽  
Late Pregnancy ◽  
Cardiac Monitoring ◽  
Control Group ◽  
Research Subjects ◽  
Neonatal Asphyxia ◽  
The Difference ◽  
Experimental Group

With the adoption of the two-child policy, there has been a large increase in women of older maternal and high-risk pregnant women. So, it is necessary to analyze the health status of women in the late pregnancy on time. To analyze the effect on using remote fetal monitoring on women in the late pregnancy, we selected women in the late stage of pregnancy in our hospital as research subjects. They were randomly divided into two groups: the experimental group, which engaged in remote fetal monitoring, and the control group, which adopted traditional cardiac monitoring. In order to get more effective data, we used the Kalman filter and audio repair algorithms to preprocess the collected data. During follow-up observation, we compared the two groups using neonatal cardiac monitoring by employing the non-stress test and observed the occurrence of neonatal asphyxia. The incidence of neonatal abnormal non-stress test in the experimental group and the control group was 33.6% and 17.3%, respectively; the difference was statistically significant ( p < 0.05). The incidence of neonatal asphyxia in the experimental group was 12.5%, which was significantly lower than in the control group (30%; p < 0.05). We have found that women in the late stage of pregnancy who adopted remote fetal monitoring could detect abnormal non-stress test earlier and thus increase in the detection of rate of neonatal asphyxia.

scholarly journals Regulation of accretion by its outflow in a symbiotic star: the 2016 outflow fast state of MWC 560

2020 ◽  
Vol 492 (3) ◽  
pp. 3107-3127 ◽  
Author(s):  
Adrian B Lucy ◽  
J L Sokoloski ◽  
U Munari ◽  
Nirupam Roy ◽  
N Paul M Kuin ◽  
...  
Keyword(s):  
Symbiotic Star ◽  
Fast State ◽  
Low Velocity ◽  
X Ray ◽  
Broad Absorption Line ◽  
Multi Wavelength ◽  
Order Of Magnitude ◽  
The Stability ◽  
Ultraviolet Observations ◽  
Optical Flux

ABSTRACT How are accretion discs affected by their outflows? To address this question for white dwarfs accreting from cool giants, we performed optical, radio, X-ray, and ultraviolet observations of the outflow-driving symbiotic star MWC 560 (≡V694 Mon) during its 2016 optical high state. We tracked multi-wavelength changes that signalled an abrupt increase in outflow power at the initiation of a months-long outflow fast state, just as the optical flux peaked: (1) an abrupt doubling of Balmer absorption velocities; (2) the onset of a 20 μJy per month increase in radio flux; and (3) an order-of-magnitude increase in soft X-ray flux. Juxtaposing to prior X-ray observations and their coeval optical spectra, we infer that both high-velocity and low-velocity optical outflow components must be simultaneously present to yield a large soft X-ray flux, which may originate in shocks where these fast and slow absorbers collide. Our optical and ultraviolet spectra indicate that the broad absorption-line gas was fast, stable, and dense (≳106.5  cm−3) throughout the 2016 outflow fast state, steadily feeding a lower density (≲105.5 cm−3) region of radio-emitting gas. Persistent optical and ultraviolet flickering indicate that the accretion disc remained intact. The stability of these properties in 2016 contrasts to their instability during MWC 560’s 1990 outburst, even though the disc reached a similar accretion rate. We propose that the self-regulatory effect of a steady fast outflow from the disc in 2016 prevented a catastrophic ejection of the inner disc. This behaviour in a symbiotic binary resembles disc/outflow relationships governing accretion state changes in X-ray binaries.

Development of one-axis controlled bearingless motor and its application to a centrifugal pump for extremely low temperature

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1287-1294
Author(s):  
Hirohisa Kato ◽  
Mochimitsu Komori ◽  
Ken-ichi Asami ◽  
Nobuo Sakai
Keyword(s):  
Low Temperature ◽  
Centrifugal Pump ◽  
Liquid Nitrogen ◽  
Flow Rate ◽  
Maximum Flow ◽  
Magnetic Bearing ◽  
Lubricating Oil ◽  
Bearingless Motor ◽  
The Difference ◽  
Conventional Study

In this paper, a centrifugal pump for for extremely low temperature was fabricated and evaluated by experiments in liquid nitrogen. The pump is using a bearingless motor and permanent magnet bearings to levitate and rotate the rotor without lubricating oil. The difference from the conventional study is that a one-axis controlled bearingless motor is used to reduce the magnetic bearing cost and that the bearings are installed in the liquid to eliminate a shaft-seal. Stable levitation and rotation of the rotor were confirmed in the rotation and pump experiments in liquid nitrogen. In pump experiment, the flow rate of liquid nitrogen was measured at 1 cm in a pumping height. The maximum flow rate was 1.3 L/min when the rotation speed is 1,800 rpm.

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