The Experimental Study of Impinging Interaction of Rarefied Gas Jet With Plane Wall Using LIF Method

2011 ◽  
Author(s):  
Shunsuke Yamazaki ◽  
Ai Yanagi ◽  
Yusaku Tanaka ◽  
Masanori Ota ◽  
Kazuo Maeno
Keyword(s):  
Attitude Control ◽  
Rarefied Gas ◽  
Artificial Satellite ◽  
Low Pressure ◽  
Point Of View ◽  
Plane Wall ◽  
Gas Jet ◽  
Laser Material Processing ◽  
Aerospace Technology ◽  
Ion Laser

Discharging gas jets in low-pressure conditions are interesting and important phenomena from an engineering point of view. For example, in aerospace technology they relate to the gas jet thruster for attitude control of artificial satellite, or in laser technology assist gas behavior for laser material processing under low pressure. The jets, however, deform to the complicated shapes by interacting with solid walls. This paper deals with a visualization experiment on the interacting jet and plane wall by applying LIF (Laser Induced Fluorescence) method using an Ar-ion laser. We have obtained a series of jet-wall interacting images at various distances and clarified the behavior of impinging jet to the plane wall.

Flow of Rarefied Gas over Plane Wall

1970 ◽  
Vol 29 (2) ◽  
pp. 495-508 ◽  
Author(s):  
Yoshio Sone ◽  
Kyoji Yamamoto
Keyword(s):  
Rarefied Gas ◽  
Plane Wall

Stability of a Piezoresistive Ceramic Pressure Sensor Made With LTCC Technology

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000371-000376 ◽  
Author(s):  
Marina Santo Zarnik ◽  
Darko Belavic
Keyword(s):  
Pressure Sensor ◽  
Fatigue Testing ◽  
Low Pressure ◽  
Fatigue Tests ◽  
Point Of View ◽  
Long Term Stability ◽  
Pressure Cycling ◽  
Key Characteristics ◽  
The Stability

This paper discusses the stability of a piezoresistive, LTCC-based, pressure sensor that was designed for measurements in a low-pressure range below 100 mbar. The intrinsic stability of the sensor's offset was evaluated at a constant ambient temperature and different conditions regarding the atmospheric humidity. The sensors were also subjected to functional fatigue tests, which included a full-scale and an overload pressure cycling. The results of the fatigue testing revealed the vulnerability of the sensor's structure from the point of view of the long-term stability and the life-cycle. Nevertheless, the stability of the key characteristics of the prototype sensors was found to be satisfactory for accurate measurements in the low-pressure ranges.

Constrained on-board attitude control using gas jet thrusters

1999 ◽  
Vol 103 (1030) ◽  
pp. 549-556 ◽  
Author(s):  
G. Radice ◽  
C. R. Mclnnes
Keyword(s):  
Potential Function ◽  
Attitude Control ◽  
Computational Effort ◽  
Potential Functions ◽  
Geometric Configuration ◽  
Gas Jet ◽  
New Approach ◽  
Safety Critical ◽  
Current Attitude ◽  
Lyapunov’S Theorem

Abstract This paper analyses a new approach utilising potential functions to autonomously control constrained attitude slew manoeuvres using gas jet thrusters. The method hinges on defining a potential function from the geometric configuration of the satellite's current attitude, the final target attitude and any pointing constraint which may be present. It will be demonstrated that complex path shaping and planning can be achieved using little computational effort. The method is mathematically validated using Lyapunov's theorem, and so can be considered for safety critical applications.

Monitoring of a controlled space flexible multibody by means of embedded piezoelectric sensors and cameras synergy

2018 ◽  
Vol 29 (14) ◽  
pp. 2966-2978 ◽  
Author(s):  
Matteo Ribet ◽  
Marco Sabatini ◽  
Luca Lampani ◽  
Paolo Gasbarri
Keyword(s):  
Optical Sensors ◽  
Attitude Control ◽  
Point Of View ◽  
Vibration Monitoring ◽  
Structural Vibration ◽  
Elastic Displacement ◽  
Experimental Point ◽  
Solar Panels ◽  
Flexible Multibody ◽  
Usual Solution

Interaction between elastic dynamics and attitude control is a serious problem in space operations, which often involve satellites with highly flexible appendages. Monitoring and eventually control of the vibrations are a major concern to avoid a decrease in the expected performance. In particular, the classic case of a central bus with two lateral appendages (solar panels) is considered. The design of a system for structural vibration monitoring is proposed both from a numerical and an experimental point of view. Piezoelectric devices are a usual solution for measuring the deformation of the structures. In the proposed work, optical sensors are also implemented: the combined use of the two sets allows for the monitoring of the elastic displacement of the solar panels and for the reconstruction of the modal shapes of the entire flexible multibody system.

Flow of Rarefied Gas over Plane Wall

1979 ◽  
Vol 47 (2) ◽  
pp. 672-672 ◽  
Author(s):  
Yoshio Sone ◽  
Yoshimoto Onishi
Keyword(s):  
Rarefied Gas ◽  
Plane Wall

LBLOCA Analysis of CPR1000 NPP With Advanced Accumulator

2013 ◽  
Author(s):  
Hongwei Hu ◽  
Jianqiang Shan ◽  
Junli Gou ◽  
Bo Zhang ◽  
Haitao Wang ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Reactor Core ◽  
Low Pressure ◽  
Point Of View ◽  
Primary Coolant ◽  
Pressure Drops ◽  
The Core ◽  
Injection Pump ◽  
Model Combining ◽  
Large Flow

Large break LOCA (LBLOCA) is one of the limit design basic accidents in nuclear power plant. The large flow water in the advanced accumulator is injected into primary loop in early short time. When the vessel pressure drops and reactor core is re-flooded, the advanced accumulator provides a small injection flow to keep the reactor core in flooded condition. Thus, the startup grace time of the low pressure safety injection pump is extended, and the core still stays in a long-term cooling state. By deducing the original accumulator model in RELAP5 accident analysis code, a new model combining the advanced and the traditional accumulator is obtained and coupled into RELAP5/ MOD 3.3. Simulation results show that there is a large flow in the advanced accumulator at the initial stage. When the accumulator water level is lower than the stand pipe, a vortex appears in the damper, resulting in a large pressure drop and small flow. The phenomenon meets the demand of the advanced accumulator design and the simulation of the advanced accumulator is accomplished successfully. Based on this, the primary coolant loop cold leg double-ended guillotine break LBLOCA in CPR1000 is analyzed with the modified RELAP5 code. When the double ended cold leg guillotine accident with 200s delayed startup of the low pressure safety injection occurs, maximum cladding temperature in the core with traditional accumulator is 1860K which seriously exceeded the safety temperature (1477K)[1] prescribed limits while the maximum cladding temperature with advanced accumulator has the security temperature-1277K. From this point of view, adopting passive advanced accumulator can strive a longer grace time for LPSI. Thus the reliability, security and economy of reactor system were improved.

Laser Assisted Photodeposition of Gold on Semiconducting Material

1989 ◽  
Vol 152 ◽  
Author(s):  
N. V. Joshi ◽  
P. Quintero ◽  
H. Galindo ◽  
Virginia Otero de Joshi
Keyword(s):  
Ohmic Contacts ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Low Noise ◽  
Electrical Contacts ◽  
Point Of View ◽  
Continuous Exposure ◽  
Ion Laser ◽  
Diluted Magnetic ◽  
Concentrated Solution

ABSTRACTRecently, much interest has been created in laser driven chemical reactions and their application towards photodeposition of thin films of metals on semiconducting substrates. The next logical step is to verify the capability of this technique in making adequate electrical contacts for microelectronic fabrications and for circuit writing. Some work in this direction has been reported for Iron and Tungsten. However, deposition of gold has not been reported so far, even though it is very significant from the technological point of view. Therefore, we are proposing here a method for photodeposition of gold.this pupose, Pyridine gold (III) trichloride was found to be adequated and it was prepared by a conventional method, then dried under vacuum for 48 hours. A concentrated solution was made by dissolving it in Dimethyl sulfoxide. A tiny drop of it was put on the substrate and exposed to radiation 488 nm, obtained from an argon ion laser. The time of photodeposition depends upon the power of the beam; for 2 watt/mm2 and for four to six minutes of continuous exposure, good, low noise, reliable and nearly ohmic contacts were obtained.The method is found to be suitable for both conventional and non conventional semiconductors such as ZnTe, doped and undoped ZnSe, and diluted magnetic semiconductors such as Zn1−xMnxSe for which normally used methods are not applicable. The present technique can also be extended to the hiqh Tc superconductor YBa2Cu3O7. The possible mechanism of photodeposition is also discussed.

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