Composite gyroscope with high sensitivity in the low-velocity region and no dead zone

2020 ◽  
Vol 37 (2) ◽  
pp. 540
Author(s):  
Weiguo Jiang ◽  
Yundong Zhang ◽  
Jinfang Wang ◽  
Kai Ma ◽  
Fuxing Zhu ◽  
...  
Keyword(s):  
Dead Zone ◽  
High Sensitivity ◽  
Low Velocity ◽  
Velocity Region

scholarly journals CFD Modeling of Multiphase Flow in an SKS Furnace: The Effect of Tuyere Arrangements

2021 ◽  
Author(s):  
Kezhou Song ◽  
Ari Jokilaakso
Keyword(s):  
Cfd Simulation ◽  
Dead Zone ◽  
Copper Smelting ◽  
Cfd Modeling ◽  
Water Model ◽  
Bubble Plume ◽  
Low Velocity ◽  
Vof Model ◽  
The Difference ◽  
Velocity Region

AbstractThe emerging bottom blown copper smelting (SKS) technology has attracted growing interest since it came into production. To further reveal the agitation behavior inside the bath and optimize the variable parameters, CFD simulation was conducted on a scaled down SKS furnace model with different tuyere arrangements. The Multi-Fluid VOF model was used for the first time in SKS furnace simulation and the simulated results show good agreement with an experimental water model reported in the literature, in terms of plume shape and surface wave. It was found that a low velocity region would appear on the opposite side of the bubble plume and persisted for a long time. To enhance the agitation in the low velocity region and reduce the dead zone area, an arrangement with tuyeres installed at each side of the furnace was recommended. Results suggested that a smaller tuyere angle difference would help to strengthen the agitation in the system. However, further investigation indicated that the difference in tuyere angle between two rows of tuyeres should be limited within a certain range to balance the requirements of higher agitation efficiency and longer lining refractory lifespan.

scholarly journals Optimization of Velocity Flap Structures in High Sensitivity Macrofluidic Airflow Sensor

2018 ◽  
Vol 7 (4.27) ◽  
pp. 11
Author(s):  
Mohamad Dzulhelmy bin Amari ◽  
Muhamad Saifuddin b. Abdull Shukor ◽  
Sukarnur Che Abdullah
Keyword(s):  
High Sensitivity ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Fast Detection ◽  
Intelligent Control System ◽  
Highly Sensitive ◽  
Computational Fluid Dynamics Cfd ◽  
Airflow Sensor ◽  
Program Software

Automated reaction from the system is most important in fulfilling the requirement of the intelligent control system. Hence, many related studies regarding in developing the hardware of the system such as high sensitivity of the airflow sensor in detecting the changes either in user or the environment. The effect of the fast detection of the sensor through the high sensitivity of the airflow sensor have enable the system to identify and analyze the behavior of the user in higher accuracy compared to conventional system. Within the scope of airflow sensitivity, separation between two parts in the airflow sensor in altering the velocity impact have been inquired in purpose, while a few investigations in relations to determine the pressure contour of the main parts have been explored by application of using Computational Fluid Dynamics (CFD. This simulation is performed in the ANSYS program software. Thus, this study consequently intends to be focus on detection the high sensitivity of the airflow movement by distinguishing the high and low velocity impact. The optimization the airflow sensor in this study based on design parameter also done in order to design and develop a highly sensitive airflow sensor   

scholarly journals Structure of accretion flows in the nova-like cataclysmic variable RW Tri

2020 ◽  
Vol 497 (2) ◽  
pp. 1475-1487
Author(s):  
G Subebekova ◽  
S Zharikov ◽  
G Tovmassian ◽  
V Neustroev ◽  
M Wolf ◽  
...  
Keyword(s):  
Binary Systems ◽  
Cataclysmic Variable ◽  
Low Velocity ◽  
Time Resolved ◽  
Narrow Component ◽  
Accretion Flows ◽  
Photometric Observations ◽  
Hα Emission ◽  
Usual Interpretation ◽  
Velocity Region

ABSTRACT We obtained photometric observations of the nova-like (NL) cataclysmic variable RW Tri and gathered all available AAVSO and other data from the literature. We determined the system parameters and found their uncertainties using the code developed by us to model the light curves of binary systems. New time-resolved optical spectroscopic observations of RW Tri were also obtained to study the properties of emission features produced by the system. The usual interpretation of the single-peaked emission lines in NL systems is related to the bi-conical wind from the accretion disc’s inner part. However, we found that the Hα emission profile is comprised of two components with different widths. We argue that the narrow component originates from the irradiated surface of the secondary, while the broader component’s source is an extended, low-velocity region in the outskirts of the accretion disc, located opposite to the collision point of the accretion stream and the disc. It appears to be a common feature for long-period NL systems – a point we discuss.

A simultaneous inversion of seismic traveltimes and amplitudes for velocity and attenuation

Geophysics ◽  
1996 ◽  
Vol 61 (6) ◽  
pp. 1738-1757 ◽  
Author(s):  
Don W. Vasco ◽  
John E. Peterson ◽  
Ernest L. Majer
Keyword(s):  
Perturbation Approach ◽  
Well Log ◽  
Ray Theory ◽  
Fracture Zones ◽  
Low Velocity ◽  
Simultaneous Inversion ◽  
Attenuation Structure ◽  
Paraxial Ray ◽  
The Relationship ◽  
Velocity Region

It is possible to efficiently use traveltime and amplitude information to infer variations in velocity and Q. With little additional computation, terms accounting for source radiation pattern and receiver coupling may be included in the inversion. The methodology is based upon a perturbation approach to paraxial ray theory. The perturbation approach linearizes the relationship between velocity deviations and traveltime and amplitude anomalies. Using the technique, we infer the velocity and attenuation structure at a fractured granitic site near Raymond, California. A set of four well pairs are examined and each is found to contain two zones of strong attenuation. The velocity variations contain an upper low velocity region corresponding to the uppermost attenuating zone. The location of these zones agrees with independent well‐log and geophysical data. The velocity and attenuation anomalies appear to coincide with extensively fractured sections of the borehole and may indicate fracture zones rather than individual fractures.

scholarly journals A three-dimensional study of a crustal low velocity region beneath the 9°03′N overlapping spreading center

2003 ◽  
Vol 30 (2) ◽  
Author(s):  
S. Bazin ◽  
A. J. Harding ◽  
G. M. Kent ◽  
J. A. Orcutt ◽  
S. C. Singh ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Spreading Center ◽  
Low Velocity ◽  
Velocity Region

Research Progress in High Velocity Penetration into Concrete Theory

2013 ◽  
Vol 405-408 ◽  
pp. 2487-2491
Author(s):  
Cun Cheng Shi ◽  
Xin Fan ◽  
Sheng Guo Zou ◽  
Meng Shen Li
Keyword(s):  
Material Properties ◽  
High Velocity ◽  
Target Material ◽  
Low Velocity Impact ◽  
Research Progress ◽  
Future Research ◽  
Low Velocity ◽  
The Earth ◽  
Hypervelocity Penetration ◽  
Velocity Region

With the development of the earth penetration weapon, the research interest has gradually changed from low velocity impact to high velocity or hypervelocity penetration. This paper reviews the the theoretic research status on velocity region ascertaining of penetration, the target material properties near penetration cavity and mass abrasion of projectiles in high velocity penetration, and makes suggestions on the future research.

Hot-Wire Measurements Inside a Centrifugal Fan Impeller

1989 ◽  
Vol 111 (4) ◽  
pp. 363-368 ◽  
Author(s):  
A. Kjo¨rk ◽  
L. Lo¨fdahl
Keyword(s):  
Suction Side ◽  
Design Flow ◽  
Shear Stresses ◽  
Centrifugal Fan ◽  
Reynolds Stresses ◽  
Low Velocity ◽  
Mean Velocity ◽  
Attached Flow ◽  
The Mean ◽  
Velocity Region

Measurements of the three mean velocity components and five of the Reynolds stresses have been carried out in the blade passage of a centrifugal fan impeller. The impeller was of ordinary design, with nine backward curved blades, and all measurements were carried out at the design flow rate. The mean velocity measurements show that the flow can be characterized as an attached flow with almost linearly distributed velocity profiles. However, in a region near the suction side close to the shroud a low velocity region is created. From the turbulence measurements it can be concluded that relatively low values of the turbulent stresses are predominating in the center region of the channel. Closer to the walls higher values of the normal as well as shear stresses are noted.

scholarly journals STRUCTURE OF A FLAME FRONT PROPAGATING AGAINST THE FLOW NEAR A COLD WALL

2002 ◽  
Vol 12 (11) ◽  
pp. 2547-2555 ◽  
Author(s):  
VADIM N. KURDYUMOV ◽  
AMABLE LIÑÁN
Keyword(s):  
Flame Front ◽  
Velocity Gradient ◽  
Front Propagation ◽  
Lewis Number ◽  
Critical Value ◽  
Constant Density ◽  
Density Approximation ◽  
Cold Wall ◽  
Low Velocity ◽  
Velocity Region

The flashback or propagation of premixed flames against the flow of a reacting mixture, along the low velocity region near a cold wall, is investigated numerically. The analysis, carried out using the constant density approximation for an Arrhenius overall reaction, accounts for the effects of the Lewis number of the limiting reactant. Flame front propagation and flashback are only possible for values of the near wall velocity gradient below a critical value. The flame propagation becomes chaotic for small values of the Lewis number.

scholarly journals Performance Enhancement Methods for the Distributed Acoustic Sensors Based on Frequency Division Multiplexing

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 617 ◽  
Author(s):  
Yanzhu Hu ◽  
Zhen Meng ◽  
Mohammadmasoud Zabihi ◽  
Yuanyuan Shan ◽  
Siyi Fu ◽  
...  
Keyword(s):  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Dead Zone ◽  
High Sensitivity ◽  
Time Domain Reflectometry ◽  
System Structure ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Rayleigh Backscattering ◽  
Sensing System

The last years have witnessed the wide application of Distributed Acoustic Sensor (DAS) systems in several fields, such as submarine cable monitoring, seismic wave detection, structural health monitoring, etc. Due to their distributed measurement ability and high sensitivity, DAS systems can be employed as a promising tool for the phase sensitive optical time domain reflectometry (Φ-OTDR). However, it is also well-known that the traditional Φ-OTDR system suffers from Rayleigh backscattering (RBS) fading effects, which induce dead zones in the measurement results. Worse still, in practice it is difficult to achieve the optimum matching between spatial resolution (SR) and signal to noise ratio (SNR). Further, the overall frequency response range (FRR) of the traditional Φ-OTDR is commonly limited by the length of the fiber in order to prevent RBS signals from overlapping with each other. Additionally, it is usually difficult to reconstruct high frequency vibration signals accurately for long range monitoring. Aiming at solving these problems, we introduce frequency division multiplexing (FDM) that makes it easier to improve the system performance with less system structure changes. We propose several novel Φ-OTDR schemes based on Frequency Division Multiplexing (FDM) technology to solve the above problems. Experimental results showed that the distortion induced by fading effects could be suppressed to 1.26%; when the SR of Φ-OTDR is consistent with the length of the vibration region, the SNR of the sensing system is improved by 3 dB compared to the average SNR with different SRs; vibration frequencies up to 440 kHz have been detected along 330 m artificial microstructures. Thus, the proposed sensing system offers a promising solution for the performance enhancement of DAS systems that could achieve high SNR, broadband FRR and dead zone-free measurements at the same time.

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