Thermal drift and force convection analysis of nanofluid due to partially heated triangular fins in a porous circular enclosure

2021 ◽  
Author(s):  
Rizwan Ul Haq ◽  
Syed Saqib Shah ◽  
Ebrahem Algehyne
1957 ◽  
Vol 24 (4) ◽  
pp. 506-508
Author(s):  
L. E. Goodman ◽  
A. R. Robinson

Abstract When a floated gyroscope is subjected to a temperature distribution which is not symmetrical about a plane parallel to the gravitational force, convection currents tend to rotate the gimbal. The rebalance torque and the free drift rate due to thermal effects are first determined for the case of an exactly centered gimbal. It is then shown that moderate gimbal eccentricity has little influence on thermal drift, and, in fact, reduces thermal rebalance torque.


Author(s):  
Louis T. Germinario

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).


Author(s):  
P.R. Swann ◽  
A.E. Lloyd

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.


Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1357
Author(s):  
Linxiao Cong ◽  
Jianchao Mu ◽  
Qian Liu ◽  
Hao Wang ◽  
Linlin Wang ◽  
...  

The space gravitational wave detection and drag free control requires the micro-thruster to have ultra-low thrust noise within 0.1 mHz–0.1 Hz, which brings a great challenge to calibration on the ground because it is impossible to shield any spurious couplings due to the asymmetry of torsion balance. Most thrusters dissipate heat during the test, making the rotation axis tilt and components undergo thermal drift, which is hysteretic and asymmetric for micro-Newton thrust measurement. With reference to LISA’s research and coming up with ideas inspired from proportional-integral-derivative (PID) control and multi-timescale (MTS), this paper proposes to expand the state space of temperature to be applied on the thrust prediction based on fine tree regression (FTR) and to subtract the thermal noise filtered by transfer function fitted with z-domain vector fitting (ZDVF). The results show that thrust variation of diurnal asymmetry in temperature is decoupled from 24 μN/Hz1/2 to 4.9 μN/Hz1/2 at 0.11 mHz. Additionally, 1 μN square wave modulation of electrostatic force is extracted from the ambiguous thermal drift background of positive temperature coefficient (PTC) heater. The PID-FTR validation is performed with experimental data in thermal noise decoupling, which can guide the design of thermal control and be extended to other physical quantities for noise decoupling.


2017 ◽  
Vol 17 (6) ◽  
pp. 881-885 ◽  
Author(s):  
Luigi Guerriero ◽  
Giovanni Guerriero ◽  
Gerardo Grelle ◽  
Francesco M. Guadagno ◽  
Paola Revellino

Abstract. Continuous monitoring of earth flow displacement is essential for the understanding of the dynamic of the process, its ongoing evolution and designing mitigation measures. Despite its importance, it is not always applied due to its expense and the need for integration with additional sensors to monitor factors controlling movement. To overcome these problems, we developed and tested a low-cost Arduino-based wire-rail extensometer integrating a data logger, a power system and multiple digital and analog inputs. The system is equipped with a high-precision position transducer that in the test configuration offers a measuring range of 1023 mm and an associated accuracy of ±1 mm, and integrates an operating temperature sensor that should allow potential thermal drift that typically affects this kind of systems to be identified and corrected. A field test, conducted at the Pietrafitta earth flow where additional monitoring systems had been installed, indicates a high reliability of the measurement and a high monitoring stability without visible thermal drift.


1997 ◽  
Vol 33 (9) ◽  
pp. 780 ◽  
Author(s):  
A.A. Saavedra ◽  
R. Passy ◽  
J.P. von der Weid

1965 ◽  
Vol 53 (5) ◽  
pp. 556-556
Author(s):  
B. Murari
Keyword(s):  

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