Temperature Effect in Zero-Point Drift

1981 ◽  
Vol 4 (2) ◽  
pp. 260-262
Author(s):  
Z. Kviz
Keyword(s):  
Temperature Effect ◽  
Zero Point ◽  
Temperature Drift ◽  
Pulse Counting ◽  
Atmospheric Extinction ◽  
Air Mass ◽  
The Relationship

The relationship between the observed magnitude of a star and the air-mass takes the shape of a loop. These loops are caused by the zero-point drift of the photometer in use and by the variations of the atmospheric extinction taking place during the observation (Kviz 1979). From observations where the temperature drift of the photometer and of the photomultiplier were recorded, it is evident that the sense of the loops is correlated with the physical temperature of the photo-multiplier. Measurements have been made with the Swiss telescope and the 7-colour Geneva photometer P 7 using pulse counting with PM tube EMI9798 — described in Burnet (1976) and Burnet, Rufener (1979) — at La Silla, Chile.

Magnitude-Air Mass Loops as A Diagnostic by-Product of the Photometry of Variable Stars

1979 ◽  
Vol 46 ◽  
pp. 428-431 ◽  
Author(s):  
Z. Kvíz
Keyword(s):  
Variable Star ◽  
Zero Point ◽  
Variable Stars ◽  
Comparison Star ◽  
Atmospheric Extinction ◽  
Air Mass ◽  
Extinction Coefficients ◽  
Photoelectric Equipment ◽  
East And West

If a variable star is observed with a photoelectric photometer during the whole night or at least for several hours both east and west from the meridian, the measurements of the brightness of the comparison star may yield useful information about the atmospheric extinction and about the performance of the photoelectric equipment as well. The extinction coefficients are valuable for the reduction of the data concerning the variable star itself and also for the study of the variation of atmospheric extinction at the observatory site. One of the most annoying characteristics of the photometric device is the zero-point drift during the night as a consequence of the change of the sensitivity of the photometer.The influence of the zero-point drift and the changes of extinction during the night on the Bouguer line (observed magnitude against air mass) was studied separately in a previous paper (Kviz, 1978, hereafter referred to as Paper I). In the present paper the simultaneous effects of both the zero-point drift and the changes of the extinction on the Bouguer plots are investigated.

scholarly journals The relationship between net GHG emissions and radiative forcing with an application to Article 4.1 of the Paris Agreement.

2021 ◽  
Author(s):  
Tom M. L. Wigley
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
Ghg Emissions ◽  
Zero Point ◽  
Paris Agreement ◽  
Test Case ◽  
Net Zero ◽  
Global Warming Potentials ◽  
The Relationship

Abstract This paper provides an assessment of Article 4.1 of the Paris Agreement on climate; the main goal of which is to provide guidance on how “to achieve the long-term temperature goal set out in Article 2”. Paraphrasing, Article 4.1 says that, to achieve this end, we should decrease greenhouse gas (GHG) emissions so that net anthropogenic GHG emissions fall to zero in the second half of this century. To aggregate net GHG emissions, 100-year Global Warming Potentials (GWP-100) are commonly used to convert non-CO2 emissions to equivalent CO2 emissions. As a test case using methane, temperature projections using GWP-100 scaling are shown to be seriously in error. This throws doubt on the use of GWP-100 scaling to estimate net GHG emissions. An alternative method to determine the net-zero point for GHG emissions based on radiative forcing is derived. This shows that the net-zero point needs to be reached as early as 2036, much sooner than in the Article 4.1 window. Other scientific flaws in Article 4.1 that further undermine its purpose to guide efforts to achieve the Article 2 temperature targets are discussed.

On the Measurement of Atmospheric Extinction by Rufener’s Method

1979 ◽  
Vol 3 (5) ◽  
pp. 326-327
Author(s):  
Z. KviZ
Keyword(s):  
Adverse Effect ◽  
Photometric System ◽  
Photoelectric Photometry ◽  
Atmospheric Extinction ◽  
Air Mass

The coefficient of atmospheric extinction may change during the night and in fact it often does. This has an adverse effect on the determination of atmospheric extinction by simple Bouguer plot of magnitude against air mass. This effect was studied by Rufener (1964), who introduced for the purpose of accurate photoelectric photometry in the Geneva photometric system the method of two ‘extinction stars’. His method consists of the measurement of two stars of the same colour — one starting at high air mass 2 - 3, the M-star (for French montante = rising) and the second starting simultaneously in the meridian at low air mass, the D—star (for descending).

Temperature relevant performance and calibration of spin-valve sensor

Sensor Review ◽  
2019 ◽  
Vol 39 (6) ◽  
pp. 881-886
Author(s):  
Huachen Zhu ◽  
Zhenghong Qian ◽  
Jiaofeng Zhang ◽  
Yucheng Sun ◽  
Ru Bai ◽  
...  
Keyword(s):  
Spin Valve ◽  
Temperature Stability ◽  
Lower Sensitivity ◽  
Temperature Drift ◽  
Content Type ◽  
Temperature Changes ◽  
Drift Model ◽  
Higher Temperature ◽  
Highly Correlated ◽  
The Relationship

Purpose It has been noted that the spin-valve sensor exhibits lower sensitivity with higher temperature because of the variation of GMR ratio, which could lead to the measurement error in applications where working temperature changes largely over seasons or times. This paper aims to investigate and compensate the temperature effect of the spin-valve sensor. Design/methodology/approach A spin-valve sensor is fabricated based on microelectronic process, and its temperature relevant properties are investigated, in which the transfer curves are acquired within a temperature range of −50°C to 125°C with a Helmholtz coil and temperature chamber. Findings It is found that the sensitivity of spin-valve sensor decreases with temperature linearly, where the temperature coefficient is calculated at −0.25 %/°C. The relationship between sensitivity of spin-valve sensor and temperature is well-modeled. Originality/value The temperature drift model of the spin-valve sensor’s sensitivity is highly correlated with tested results, which could be used to compensate the temperature influence on the sensor output. A self-compensation sensor system is proposed and built based on the expression modeled for the temperature dependence of the sensor, which exhibits a great improvement on temperature stability.

Experimental Study on Temperature External-Characteristics of Ni-Mn-Ga Shape Memory Alloy

2011 ◽  
Vol 311-313 ◽  
pp. 1232-1236 ◽  
Author(s):  
Yong Zhi Cai
Keyword(s):  
Experimental Study ◽  
Critical Temperature ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Temperature Effect ◽  
Deformation Rate ◽  
Variable Temperature ◽  
Temperature Characteristics ◽  
The Relationship ◽  
External Characteristics

Temperature characteristics are essential to reasonable application of Ni-Mn-Ga alloy. This paper reports an experiment equipment which is used as the research of variable temperature effect. The relationship between deformation rate and temperature is studied. Dynamic and static experiments are done. The results show that critical temperature is around 40°C. It can be predicted that thermo-elasticity and magnetically-controlled characteristics will disappear with the increase of temperature.

Temperature Drift Compensation Based on Artificial Fish Swarm Algorithm for Quartz Flexible Accelerometer

2014 ◽  
Vol 513-517 ◽  
pp. 4030-4034 ◽  
Author(s):  
Xu Dong Yu ◽  
Jin Long Li ◽  
Shu Kui Yan ◽  
Guo Wei ◽  
Geng Li
Keyword(s):  
Temperature Compensation ◽  
Stepwise Regression ◽  
Temperature Drift ◽  
Artificial Fish Swarm Algorithm ◽  
Sensor Performance ◽  
Artificial Fish Swarm ◽  
Drift Compensation ◽  
Drift Instability ◽  
Relationship Of ◽  
The Relationship

Temperature is an important factor for affecting the accuracy of quartz flexible accelerometer. The relationship of quartz flexible accelerometers drift to temperature should be established accurately which can improve the precision of inertial navigation system. In order to reduce the temperature sensitivity and improve the sensor performance, temperature drift compensation method based on artificial fish swarm (AFS) algorithm is established and the steps and methods are given. The traditional modeling method of stepwise regression is also investigated to provide a comparison with the AFS algorithm. The result shows that the temperature compensation model by AFS algorithm is accurate. The drift instability of accelerometer output is reduced from 160.2ug to 18.0ug over the temperature range from-20°Cto +50°C. The results of the stochastic temperature tests show that this method has reduced the influence of temperature variation effectively and improved the accelerometer accuracy.

scholarly journals Sixteen overlooked open clusters in the fourth Galactic quadrant

2020 ◽  
Vol 637 ◽  
pp. A95 ◽  
Author(s):  
G. I. Perren ◽  
E. E. Giorgi ◽  
A. Moitinho ◽  
G. Carraro ◽  
M. S. Pera ◽  
...  
Keyword(s):  
Zero Point ◽  
Open Clusters ◽  
Solar Neighborhood ◽  
Intrinsic Properties ◽  
Distance Analysis ◽  
Variable Level ◽  
The Galaxy ◽  
Relationship Of ◽  
The Relationship ◽  
Photometric Distance

Aims. This paper has two main objectives: (1) To determine the intrinsic properties of 16 faint and mostly unstudied open clusters in the poorly known sector of the Galaxy at 270° −300° to probe the Milky Way structure in future investigations. (2) To address previously reported systematics in Gaia DR2 parallaxes by comparing the cluster distances derived from photometry with those derived from parallaxes. Methods. Deep UBVI photometry of 16 open clusters was carried out. Observations were reduced and analyzed in an automatic way using the ASteCA package to obtain individual distances, reddening, masses, ages, and metallicities. Photometric distances were compared to those obtained from a Bayesian analysis of Gaia DR2 parallaxes. Results. Ten out of the sixteen clusters are true or highly probable open clusters. Two of them are quite young and follow the trace of the Carina Arm and the already detected warp. The remaining clusters are placed in the interarm zone between the Perseus and Carina Arms, as expected for older objects. We found that the cluster van den Berg-Hagen 85 is 7.5 × 109 yr old, which means that it is one of the oldest open clusters detected in our Galaxy so far. The relationship of these ten clusters with the Galaxy structure in the solar neighborhood is discussed. The comparison of distances from photometry and parallaxes data in turn reveals a variable level of disagreement. Conclusions. Various zero-point corrections for Gaia DR2 parallax data recently reported were considered for a comparison between photometry- and parallax-based distances. The results tend to improve with some of these corrections. Photometric distance analysis suggests an average correction of ∼+0.026 mas (to be added to the parallaxes). The correction may have a more intricate dependence on distance, but addressing this level of detail will require a larger cluster sample.

scholarly journals The Relationship between Air-Mass Trajectories and the Abundance of Dust-Borne Prokaryotes at the SE Mediterranean Sea

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 280 ◽  
Author(s):  
Eyal Rahav ◽  
Natalia Belkin ◽  
Adina Paytan ◽  
Barak Herut
Keyword(s):  
Mediterranean Sea ◽  
Temporal Variability ◽  
Airborne Microorganisms ◽  
Coastal Site ◽  
Air Mass ◽  
Dust Aerosols ◽  
Air Mass Trajectories ◽  
Airborne Microbes ◽  
The Relationship ◽  
Air Mass Trajectory

Airborne prokaryotes are transported along with dust/aerosols, yet very little attention is given to their temporal variability above the oceans and the factors that govern their abundance. We analyzed the abundance of autotrophic (cyanobacteria) and heterotopic airborne microbes in 34 sampling events between 2015–2018 at a coastal site in the SE Mediterranean Sea. We show that airborne autotrophic (0.2–7.6 cells × 103 m−3) and heterotrophic (0.2–30.6 cells × 103 m−3) abundances were affected by the origin and air mass trajectory, and the concentration of dust/aerosols in the air, while seasonality was not coherent. The averaged ratio between heterotrophic and autotrophic prokaryotes in marine-dominated trajectories was ~1.7 ± 0.6, significantly lower than for terrestrial routes (6.8 ± 6.1). Airborne prokaryotic abundances were linearly and positively correlated to the concentrations of total aerosol, while negatively correlated with the aerosol’s anthropogenic fraction (using Pb/Al or Cu/Al ratios as proxies). While aerosols may play a major role in dispersing terrestrial and marine airborne microbes in the SE Mediterranean Sea, the mechanisms involved in the dispersal and diversity of airborne microorganisms remain to be studied and should include standardization in collection and analysis protocols.

The relationship between seasonal variations of total-nitrogen and total-phosphorus in rainfall and air mass advection paths in Matsue, Japan

2009 ◽  
Vol 43 (22-23) ◽  
pp. 3496-3501 ◽  
Author(s):  
Katsuhiro Yoshioka ◽  
Hiroshi Kamiya ◽  
Yoshihiro Kano ◽  
Yukiko Saki ◽  
Masumi Yamamuro ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Seasonal Variations ◽  
Air Mass ◽  
The Relationship
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