scholarly journals Recalibrating the Wide-field Infrared Survey Explorer (WISE) W4 Filter

2014 ◽  
Vol 31 ◽  
Author(s):  
M. J. I. Brown ◽  
T. H. Jarrett ◽  
M. E. Cluver
Keyword(s):  
Response Curve ◽  
Reasonable Agreement ◽  
Planetary Nebulae ◽  
System Response ◽  
Wide Field ◽  
Effective Wavelength ◽  
Photometric Calibration ◽  
The Difference ◽  
Infrared Survey

AbstractWe present a revised effective wavelength and photometric calibration for the Wide-field Infrared Survey Explorer W4 band, including tests of empirically motivated modifications to its pre-launch laboratory-measured relative system response curve. We derived these by comparing measured W4 photometry with photometry synthesised from spectra of galaxies and planetary nebulae. The difference between measured and synthesised photometry using the pre-launch laboratory-measured W4 relative system response can be as large as 0.3 mag for galaxies and 1 mag for planetary nebulae. We find the W4 effective wavelength should be revised upward by 3.3%, from 22.1 to 22.8 μm, and the W4 AB magnitude of Vega should be revised from mW4 = 6.59 to mW4 = 6.66. In an attempt to reproduce the observed W4 photometry, we tested three modifications to the pre-launch laboratory-measured W4 relative system response curve, all of which have an effective wavelength of 22.8 μm. Of the three relative system response curve models tested, a model that matches the laboratory-measured relative system response curve, but has the wavelengths increased by 3.3% (or ≃ 0.73 μm) achieves reasonable agreement between the measured and synthesised photometry.

scholarly journals WR 72: a born-again planetary nebula with hydrogen-poor knots

2020 ◽  
Vol 492 (3) ◽  
pp. 3316-3322 ◽  
Author(s):  
V V Gvaramadze ◽  
A Y Kniazev ◽  
G Gräfener ◽  
N Langer
Keyword(s):  
Planetary Nebula ◽  
White Dwarfs ◽  
Planetary Nebulae ◽  
Wide Field ◽  
Large Telescope ◽  
Thermal Pulse ◽  
Born Again ◽  
Infrared Survey ◽  
Rare Group

ABSTRACT We report the discovery of a handful of optical hydrogen-poor (H-poor) knots in the central part of an extended infrared nebula centred on the [WO1] star WR 72, obtained by spectroscopic and imaging observations with the Southern African Large Telescope (SALT). Wide-field Infrared Survey Explorer (WISE) images of the nebula show that it is composed of an extended almost circular halo (of ≈6 arcmin or ≈2.4 pc in diameter) and an elongated and apparently bipolar inner shell (of a factor of six smaller size), within which the knots are concentrated. Our findings indicate that WR 72 is a new member of the rare group of H-poor planetary nebulae, which may be explained through a very late thermal pulse of a post-AGB star or by a merger of two white dwarfs.

scholarly journals Extinction-free Census of AGNs in the AKARI/IRC North Ecliptic Pole Field from 23-band infrared photometry from Space Telescopes

2020 ◽  
Vol 499 (3) ◽  
pp. 4068-4081 ◽  
Author(s):  
Ting-Wen Wang ◽  
Tomotsugu Goto ◽  
Seong Jin Kim ◽  
Tetsuya Hashimoto ◽  
Denis Burgarella ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Wide Field ◽  
Space Telescopes ◽  
Distribution Modelling ◽  
Star Forming ◽  
The North ◽  
Band Filter ◽  
Infrared Survey

ABSTRACT In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nucleus (AGN) is crucial. However, AGNs are often missed in optical, UV, and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (MIR) survey supported by multiwavelength data is one of the best ways to find obscured AGN activities because it suffers less from extinction. Previous large IR photometric surveys, e.g. Wide field Infrared Survey Explorer and Spitzer, have gaps between the MIR filters. Therefore, star-forming galaxy-AGN diagnostics in the MIR were limited. The AKARI satellite has a unique continuous nine-band filter coverage in the near to MIR wavelengths. In this work, we take advantage of the state-of-the-art spectral energy distribution modelling software, cigale, to find AGNs in MIR. We found 126 AGNs in the North Ecliptic Pole-Wide field with this method. We also investigate the energy released from the AGN as a fraction of the total IR luminosity of a galaxy. We found that the AGN contribution is larger at higher redshifts for a given IR luminosity. With the upcoming deep IR surveys, e.g. JWST, we expect to find more AGNs with our method.

Updating real‐time flood forecasts via the dynamic system response curve method

2015 ◽  
Vol 51 (7) ◽  
pp. 5128-5144 ◽  
Author(s):  
Wei Si ◽  
Weimin Bao ◽  
Hoshin V. Gupta
Keyword(s):  
Dynamic System ◽  
Real Time ◽  
Response Curve ◽  
System Response ◽  
Curve Method

Detection and correlation of geosynchronous objects in NASA’s Wide-field Infrared Survey Explorer images

2021 ◽  
Author(s):  
Joshua Fitzmaurice ◽  
Donald Bédard ◽  
Chris H. Lee ◽  
Patrick Seitzer
Keyword(s):  
Wide Field ◽  
Infrared Survey

scholarly journals Development of dynamic system response curve method for estimating initial conditions of conceptual hydrological models

2018 ◽  
Vol 20 (6) ◽  
pp. 1387-1400
Author(s):  
Yiqun Sun ◽  
Weimin Bao ◽  
Peng Jiang ◽  
Xuying Wang ◽  
Chengmin He ◽  
...  
Keyword(s):  
Dynamic System ◽  
Response Curve ◽  
Initial Conditions ◽  
Model Performance ◽  
System Response ◽  
Hydrological Models ◽  
Flood Prediction ◽  
Ill Posed ◽  
Value Decomposition

Abstract The dynamic system response curve (DSRC) has its origin in correcting model variables of hydrologic models to improve the accuracy of flood prediction. The DSRC method can lead to unstable performance since the least squares (LS) method, employed by DSRC to estimate the errors, often breaks down for ill-posed problems. A previous study has shown that under certain assumptions the DSRC method can be regarded as a specific form of the numerical solution of the Fredholm equation of the first kind, which is a typical ill-posed problem. This paper introduces the truncated singular value decomposition (TSVD) to propose an improved version of the DSRC method (TSVD-DSRC). The proposed method is extended to correct the initial conditions of a conceptual hydrological model. The usefulness of the proposed method is first demonstrated via a synthetic case study where both the perturbed initial conditions, the true initial conditions, and the corrected initial conditions are precisely known. Then the proposed method is used in two real basins. The results measured by two different criteria clearly demonstrate that correcting the initial conditions of hydrological models has significantly improved the model performance. Similar good results are obtained for the real case study.

Enhanced coupling of adenylate cyclase to lipolysis in permeabilized adipocytes from trained rats

1991 ◽  
Vol 71 (1) ◽  
pp. 23-29 ◽  
Author(s):  
T. Izawa ◽  
T. Komabayashi ◽  
T. Mochizuki ◽  
K. Suda ◽  
M. Tsuboi
Keyword(s):  
Adenylate Cyclase ◽  
Dose Response ◽  
Response Curve ◽  
Positive Relationship ◽  
Regression Coefficient ◽  
Permeabilized Cells ◽  
Major Mechanism ◽  
The Difference ◽  
And Control ◽  
Stimulation Of

Digitonin-permeabilized adipocytes were used to study the coupling of adenylate cyclase (AC) to lipolysis in exercise-trained rats. Isoproterenol-(IPR) stimulated lipolysis in permeabilized cells was significantly greater in trained than in control rats. Under essentially identical conditions, the dose-response curve for IPR stimulation of AC activity in the absence of 3-isobutyl-1-methylxanthine was similar in trained and control rats. However, the potency of stimulation by IPR as a percentage of the basal level was greater in trained rats. AC activity and lipolysis in the presence of 3-isobutyl-1-methylxanthine were also significantly greater in trained than in control rats. Least-squares analysis by plotting the log AC vs. lipolysis values showed that the regression coefficient was about three-fold greater in trained than in control rats. The concentration of endogenous adenosine 3′,5′-cyclic monophosphate (cAMP) needed to produce a half-maximal lipolytic response was 18.58 and 10.81 pmol.min-1.10(6) cells-1 in control and trained rats, respectively. Thus a positive relationship existed between lipolysis and AC activity, with a tighter coupling in trained rats. Lipolysis in response to exogenous cAMP tended to be greater in trained than in control rats, and the difference was statistically significant for 50 microM and 10 mM cAMP. Our finding support the concept that the major mechanism of enhanced lipolysis in trained rats was an increase in the activity of enzymatic step(s) distal to cAMP.

scholarly journals Design of Auto-tuning Relay Feedback controller for Shell Heavy Oil Fractionator

2018 ◽  
Vol 218 ◽  
pp. 02007
Author(s):  
Wahyudi ◽  
Sela Martasia ◽  
Budi Setiyono ◽  
Iwan Setiawan
Keyword(s):  
Heavy Oil ◽  
System Modeling ◽  
Control Technique ◽  
System Response ◽  
Relay Feedback ◽  
End Point ◽  
Column Type ◽  
Point Composition ◽  
Auto Tuning ◽  
The Difference

Auto-tuning relay feedback is one of the control techniques, which is used to solve the non-linear, long delay time, and disturbance's problems. This control technique is the development of Ziegler-Nichols that can be done automatically without doing system modeling. In this paper, auto-tuning relay feedback is used in the control system response to optimization of Shell Heavy Oil Fractionator (SHOF) system so the output of product composition as expected. SHOF is a distillation column type used to separate crude oil into desired products based on the difference in the boiling point of each product. PI regulators of relay feedback are used to control the valves on the SHOF with three inputs and three outputs that has been decoupled. Based on the tests, the average values of IAE at top end point composition (Y1) obtained with disturbance and no disturbance are 83.17 and 10.933, respectively. At the side end point composition (Y2), the average values of IAE with disturbance and no disturbance are obtained respectively, 336.38 and 42.3467. The average values of IAE at bottom reflux temperature (Y3) with disturbance and no disturbance are obtained 0.15 and 0.13, respectively.

Beating Effects in a Single Nonlinear Dynamical System in a Neighborhood of the Resonance

2016 ◽  
Vol 849 ◽  
pp. 76-83
Author(s):  
Jiří Náprstek ◽  
Cyril Fischer
Keyword(s):  
Harmonic Balance ◽  
Excitation Frequency ◽  
Nonlinear Dynamical System ◽  
Numerical Continuation ◽  
System Response ◽  
Algebraic Equations ◽  
Single Degree Of Freedom ◽  
Nonlinear Dynamical ◽  
The Difference ◽  
Eigen Frequency

The exact coincidence of external excitation and basic eigen-frequency of a single degree of freedom (SDOF) nonlinear system produces stationary response with constant amplitude and phase shift. When the excitation frequency differs from the system eigen-frequency, various types of quasi-periodic response occur having a character of a beating process. The period of beating changes from infinity in the resonance point until a couple of excitation periods outside the resonance area. Theabove mentioned phenomena have been identified in many papers including authors’ contributions. Nevertheless, investigation of internal structure of a quasi-period and its dependence on the difference of excitation and eigen-frequency is still missing. Combinations of harmonic balance and small parameter methods are used for qualitative analysis of the system in mono- and multi-harmonic versions. They lead to nonlinear differential and algebraic equations serving as a basis for qualitativeanalytic estimation or numerical description of characteristics of the quasi-periodic system response. Zero, first and second level perturbation techniques are used. Appearance, stability and neighborhood of limit cycles is evaluated. Numerical phases are based on simulation processes and numerical continuation tools. Parametric evaluation and illustrating examples are presented.

scholarly journals Coupling Synchronization Criterion of Two Hydraulic Motors in an Eccentric Rotary Vibration Machine

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Chun-lei Luo ◽  
Xin Mo ◽  
Jin-yang Li ◽  
Zhi-qing Tang ◽  
Song-song Huang
Keyword(s):  
Influence Factors ◽  
Resistance Coefficient ◽  
System Response ◽  
Vibration Machine ◽  
Synchronous Motion ◽  
Hydraulic Motors ◽  
The Difference ◽  
Pressure Compensation ◽  
Coupling Characteristics ◽  
Vibration Coupling

In an eccentric rotating system driven by two hydraulic motors without synchronous gears, vibration coupling may help render motion stable. In order to investigate how vibration coupling influences the motion, the coupling characteristics of the vibration system were studied regarding the differences between two motors such as leakage network, coulomb damping network, and pressure loss network, and the sensitivity of the influence factors was also studied. The influence of tiny differences between the two motors, tiny differences in the motion pair structure, in the oil temperature and in the resistance coefficient on the coupling motion were discovered, and the criterion for synchronous motion were obtained consequently. The results show that the influence of the resistance coefficient difference on system motion stability is the greatest, accounting for 46.7%, and the influence of the difference in motion pair structure (e.g. motor piston clearance) is the second, accounting for 32.8%. For motors with displacement 80 ml/r, the condition of self-synchronization is that the difference in piston clearance between the two motors is equal to or smaller than 6 μm. Experiments have proved the correctness of the theory and showed that the synchronization can be achieved by leakage compensation, damping compensation, and back-pressure compensation of the external system by means of control when the motors rotate slowly enough for system response. The study shows that the coupling synchronous model can reduce the force of the gear for the eccentricity rotary system with synchronous gear, and that the synchronous stability can be improved for the eccentricity rotary system without synchronous gear.

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