scholarly journals A New Type of Aerostatic Thrust Bearing Controlled by High-speed Pneumatic Valve and a Novel Pressure Transducer

2019 ◽  
Vol 16 (4) ◽  
pp. 7430-7446 ◽  
Author(s):  
Waheed Ur Rehman ◽  
Guiyun Jiang ◽  
Yongqin Wang ◽  
Nadeem Iqbal ◽  
Shafiq Ur Rehman ◽  
...  
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Low Cost ◽  
Research Work ◽  
Pressure Sensors ◽  
Open Loop ◽  
Machining Process ◽  
Feedback Signal ◽  
Aerostatic Bearing ◽  
Compact Size

The current research work presents a low cost, efficient and innovative active aerostatic thrust bearing which is controlled through a combination of the Arduino board, feedback transducers and high-speed valves. The purpose is to make low cost, compact active aerostatic thrust bearing with overall small dimensions and compact size. A prototype design is done in solid works with small dimensions and components are produced with the help of the high precision machining process. There are two high-speed electropneumatic valves which  are controlled through pulse width modulation techniques. These high-speed electro-pneumatic valves modify the supply pressure of aerostatic bearing to achieve desired air height gap. There are two novel pressure sensors which provide a feedback signal for control. The test bench to perform experiments has been explained. The performance of the proposed aerostatic bearing is checked both in open loop and closed loop configuration with respect to static and dynamic conditions. 

scholarly journals Dual-/Tri-Wideband Bandpass Filter with High Selectivity and Adjustable Passband for 5G Mid-Band Mobile Communications

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 205 ◽  
Author(s):  
Zhanyong Hou ◽  
Chengguo Liu ◽  
Bin Zhang ◽  
Rongguo Song ◽  
Zhipeng Wu ◽  
...  
Keyword(s):  
Mobile Communications ◽  
Communication Systems ◽  
High Speed ◽  
Bandpass Filter ◽  
Low Cost ◽  
Open Loop ◽  
Structural Deformation ◽  
Compact Structure ◽  
Compact Size ◽  
5G Mobile Communications

The design and implementation of the filters for the fifth-generation (5G) mobile communication systems are challengeable due to the demands of high integration, low-cost, and high-speed data transmission. In this paper, a dual-wideband bandpass filter (BPF) and a tri-wideband BPF for 5G mobile communications are proposed. The dual-wideband BPF consists of two folded open-loop stepped-impedance resonators (FOLSIRs), and the tri-wideband BPF is designed by placing a pair of folded uniform impedance resonator inside the dual-wideband BPF with little increase in the physical size of the filter. By employing a novel structural deformation of a stepped-impedance resonator, the FOLSIR is achieved with a more compact structure, a controllable transmission zero, and an adjustable resonant frequency. The measurement results show that the working bands of the two filters are 1.98–2.28/3.27–3.66 GHz and 2.035–2.305/3.31–3.71/4.54–5.18 GHz, respectively, which are consistent with the full-wave EM simulation results. The implemented filters have a compact size and the results show low loss, good out-of-band rejection, and wide passbands covering sub-6 GHz bands of 5G mobile communications and a commonly used spectrum.

Magnetic-Aerostatic Hybrid Bearing for Mini-Type High-Speed Air Turbine Cartridge

2011 ◽  
Author(s):  
Shih-Chun Wang ◽  
Kuang-Yuh Huang
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Magnetic Levitation ◽  
Roller Bearing ◽  
Machining Process ◽  
Aerostatic Bearing ◽  
Prototype Development ◽  
Air Turbine ◽  
Hybrid Bearing ◽  
Bearing Characteristic

Under the development trend of high speed and high efficiency, mini-type air turbines have been widely applied to high-speed dental handpieces for decades. Bearing is the key component deciding efficiency of mini-type air turbine. Friction, collision and wear are the main causes to let the traditional ball and roller bearing not be able to reach higher efficiency. Although aerostatic bearing can realize very small sliding friction, but its weak bearing characteristic limits its application. In our research, we combined a magnetic levitation bearing with an aerostatic bearing to create a novel magnetic-aerostatic hybrid bearing, which can significantly promote the mini-type air turbine in a dental handpiece to achieve a better high-speed performance. The aerostatic bearing undertakes the function of radial bearing, and the magnetic levitation is responsible for the thrust bearing. The aerostatic bearing utilizes a composite orifice form with a large depth to width aspect ratio that can be realized by simple machining process. Its radial arranged orifices provide the spindle a sufficient and uniform radial support with high pressured air film. In consideration of operational safety and size constraint of the dental handpiece, the passive magnetic levitation method with repulsive NdFeB magnet rings is adopted for the thrust bearing. For comprehending their characteristics of the aerostatic and the magnetic levitation bearings, the finite element analytical method is employed to investigate the relationship between system parameters and performance and also to deduce the optimal construction for the prototype development. Our developed magnetic-aerostatic hybrid bearing is also experimentally approved to be able to provide stable and sustainable bearing capacity under low air pressure condition.

Novel Taxonomy to Select Fog Products and Challenges Faced in Fog Environments

2021 ◽  
pp. 2558-2571
Author(s):  
Akashdeep Bhardwaj
Keyword(s):  
Cloud Computing ◽  
Distributed Computing ◽  
High Speed ◽  
Low Cost ◽  
Fog Computing ◽  
Research Work ◽  
Cloud Services ◽  
Smart Devices ◽  
Viable Solution ◽  
Last Mile

This article describes how the rise of fog computing to improve cloud computing performance and the acceptance of smart devices is slowly but surely changing our future and shaping the computing environment around us. IoT integrated with advances in low cost computing, storage and power, along with high speed networks and big data, supports distributed computing. However, much like cloud computing, which are under constant security attacks and issues, distributed computing also faces similar challenges and security threats. This can be mitigated to a great extent using fog computing, which extends the limits of Cloud services to the last mile edge near to the nodes and networks, thereby increasing the performance and security levels. Fog computing also helps increase the reach and comes across as a viable solution for distributed computing. This article presents a review of the academic literature research work on the Fog Computing. The authors discuss the challenges in Fog environment and propose a new taxonomy.

scholarly journals Review on Pressure Sensors: A Perspective from Mechanical to Micro-electro-mechanical systems

2021 ◽  
Author(s):  
Ankur Gupta
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Pressure Sensors ◽  
Micro Electro Mechanical System ◽  
Single Chip ◽  
Micro Electro Mechanical Systems ◽  
Compact Size ◽  
Wide Range ◽  
Fabrication Procedure ◽  
Application Requirements

Swiftly emerging research prospects in the Micro-Electro-Mechanical System (MEMS) enable to build of complex and sophisticated microstructures on a substrate containing moving masses, cantilevers, flexures, levers, linkages, dampers, gears, detectors, actuators, and many more on a single chip. One of the MEMS initial products that emerged into the micro-system technology is the MEMS pressure sensor. Because of their high performance, low cost, and compact size, these sensors are extensively being adopted in numerous applications viz., aerospace, automobile, and bio-medical domain, etc. These application requirements drive and impose tremendous conditions on sensor design to overcome the tedious design and fabrication procedure before its reality. MEMS-based pressure sensors enable a wide range of pressure measurements as per the application requirements. Considering its vast utility in industries, this paper presents a detailed review of MEMS-based pressure sensors and their wide area of applications, their design aspects, and challenges, to provide state of an art gist to the researchers of a similar domain in one place.

scholarly journals Active meta polarizer for terahertz frequencies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hang Wong ◽  
Kai Xu Wang ◽  
Laure Huitema ◽  
Aurelian Crunteanu
Keyword(s):  
High Speed ◽  
Phase Change Materials ◽  
High Efficiency ◽  
Low Cost ◽  
Single Layer ◽  
Intense Laser ◽  
Laser Source ◽  
Terahertz Waves ◽  
Compact Size ◽  
Thz Waves

Abstract Active meta polarizers based on phase-change materials have recently led to emerging developments in terahertz devices and systems for imaging, security, and high-speed communications. Existing technologies of adaptive control of meta polarizers are limited to the complexity of external stimuli. Here, we introduce an active terahertz polarizer consisting of a single layer of large array patterns of vanadium dioxide material integrated with metallic patch matrix to dynamically reconfigure the polarization of the terahertz waves. The proposed active polarizer is simple in structure and can independently manipulate the polarization of the incident THz waves in two orthogonal directions. In addition, the device can also be performing as a highly efficient reflector at the same frequencies. We demonstrate that efficient and fast polarization changes of THz waves can be achieved over a wide operating bandwidth. Compared with other active polarizers using mechanical, optical and thermal controls, it can be conveniently manipulated with DC bias without any external actuators, intense laser source or heater. Therefore, with the advantages of high efficiency, compact size, low loss, low cost and fast response, the proposed polarizer can be highly integrative and practical to operate within adaptive terahertz circuits and systems.

Progress of liquid crystal adaptive optics for applications in ground-based telescopes

2020 ◽  
Vol 494 (3) ◽  
pp. 3536-3540
Author(s):  
Xingyun Zhang ◽  
Zhaoliang Cao ◽  
Quanquan Mu ◽  
Dayu Li ◽  
Zenghui Peng ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Liquid Crystal ◽  
Adaptive Optics ◽  
Low Cost ◽  
Response Speed ◽  
Open Loop ◽  
Loop Control ◽  
Compact Size ◽  
Control Scheme ◽  
Resolution Imaging

ABSTRACT Liquid crystal (LC) adaptive optics systems (AOS) can potentially be used in ground-based large aperture telescopes, because of their high spatial resolution, low cost and compact size. However, their disadvantages, such as low energy efficiency and slow response speed, still hinder their application. In this paper, we demonstrate solutions to these problems. With newly synthesized fast nematic LC material and using an overdriving technique, the response time of a LC wavefront corrector was reduced to 0.75 ms. Under an open-loop control scheme, a novel optical system was designed to improve the energy efficiency of LC AOS. With those problems resolved, a LC AOS was built for a 1.23-m telescope. This system has a disturbance rejection bandwidth of 80 Hz, and could fully use the energy of 400–900 nm wavebands. Observation results showed that the diffraction limit resolution imaging of the telescope could be obtained after correction, which indicates that the LC AOS is ready to be used in ground-based telescopes for visible waveband imaging.

Novel Taxonomy to Select Fog Products and Challenges Faced in Fog Environments

2018 ◽  
Vol 1 (1) ◽  
pp. 35-49 ◽  
Author(s):  
Akashdeep Bhardwaj
Keyword(s):  
Cloud Computing ◽  
Distributed Computing ◽  
High Speed ◽  
Low Cost ◽  
Fog Computing ◽  
Research Work ◽  
Cloud Services ◽  
Smart Devices ◽  
Viable Solution ◽  
Last Mile

This article describes how the rise of fog computing to improve cloud computing performance and the acceptance of smart devices is slowly but surely changing our future and shaping the computing environment around us. IoT integrated with advances in low cost computing, storage and power, along with high speed networks and big data, supports distributed computing. However, much like cloud computing, which are under constant security attacks and issues, distributed computing also faces similar challenges and security threats. This can be mitigated to a great extent using fog computing, which extends the limits of Cloud services to the last mile edge near to the nodes and networks, thereby increasing the performance and security levels. Fog computing also helps increase the reach and comes across as a viable solution for distributed computing. This article presents a review of the academic literature research work on the Fog Computing. The authors discuss the challenges in Fog environment and propose a new taxonomy.

scholarly journals EyeLoop: An Open-Source System for High-Speed, Closed-Loop Eye-Tracking

2021 ◽  
Vol 15 ◽  
Author(s):  
Simon Arvin ◽  
Rune Nguyen Rasmussen ◽  
Keisuke Yonehara
Keyword(s):  
Eye Tracking ◽  
Open Source ◽  
High Speed ◽  
Closed Loop ◽  
Low Cost ◽  
Open Loop ◽  
Eye Tracker ◽  
High Resource ◽  
Real Time Analysis ◽  
Loop Design

Eye-trackers are widely used to study nervous system dynamics and neuropathology. Despite this broad utility, eye-tracking remains expensive, hardware-intensive, and proprietary, limiting its use to high-resource facilities. It also does not easily allow for real-time analysis and closed-loop design to link eye movements to neural activity. To address these issues, we developed an open-source eye-tracker – EyeLoop – that uses a highly efficient vectorized pupil detection method to provide uninterrupted tracking and fast online analysis with high accuracy on par with popular eye tracking modules, such as DeepLabCut. This Python-based software easily integrates custom functions using code modules, tracks a multitude of eyes, including in rodents, humans, and non-human primates, and operates at more than 1,000 frames per second on consumer-grade hardware. In this paper, we demonstrate EyeLoop’s utility in an open-loop experiment and in biomedical disease identification, two common applications of eye-tracking. With a remarkably low cost and minimum setup steps, EyeLoop makes high-speed eye-tracking widely accessible.

scholarly journals Tool Wear Progression and its Effect on Energy Consumption in Turning of Titanium Alloy (Ti-6Al-4V)

2019 ◽  
Vol 10 (2) ◽  
pp. 373-382 ◽  
Author(s):  
Muhammad Younas ◽  
Syed Husain Imran Jaffery ◽  
Mushtaq Khan ◽  
Riaz Ahmad ◽  
Liaqat Ali ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Energy Consumption ◽  
Tool Life ◽  
High Speed ◽  
Research Work ◽  
Cutting Conditions ◽  
Machining Process ◽  
Cutting Condition ◽  
Machining Conditions ◽  
Dry Conditions

Abstract. To achieve greater productivity, titanium alloy requires cutting at higher speeds (above 100 m min−1) that affects the tool life and energy consumption during the machining process. This research work correlates the wear progression and Specific Cutting Energy (SCE) in turning Ti-6Al-4V alloy using H13 tools (uncoated carbide) in dry conditions from low to high cutting speeds. Cutting condition employed in this study were selected from published wear map developed for titanium (Ti-6Al-4V alloy) with the same tool. Flank wear growth of the tool has been investigated at different length of cuts in correlation with the SCE under different cutting conditions. The useful tool life was found to be shorter at high-speed machining conditions, thus the end of useful tool life criteria (ISO 3685) was reached at a much shorter length of cuts as compared to low-speed machining conditions. The cutting conditions corresponding to high wear rate also resulted in high SCE. Finally, SCE and wear have been related by a linear relationship that can be used to monitor wear and/or SCE utilization during machining. The results help in the selection of appropriate cutting conditions that will enhance the tool life and minimize SCE consumption during machining titanium alloy.

scholarly journals Performance Analysis for Open Loop Brushless DC Motor Drive

2019 ◽  
Vol 8 (6) ◽  
pp. 1220-1228
Keyword(s):  
High Speed ◽  
High Reliability ◽  
Research Work ◽  
Load Condition ◽  
Open Loop ◽  
Voltage Source ◽  
Motor Drive ◽  
Bldc Motor ◽  
Good Efficiency ◽  
Rotor Position

This paper presents a broad explanation on the effect of performance of an open-loop representation of a Brushless Direct Current (BLDC) Motor drive supplied from a two-level voltage source inverter (VSI) working on 120-degree mode of conduction. This research work is programming based and it is done in the MATLAB software for both No-load and load condition. BLDC motors are currently growing popularity and replacing brush motor in so many applications, as it can be used in both low and high-speed vehicle system and also in servo drives. The high reliability, good efficiency, high power concentration, less maintenance, simplicity of control and mainly the brushless operation make the BLDC motors superior to others. The presence of electronic elements for the smooth operation of the motor makes it less costly compare to other motors. It has a permanent magnet as a rotor with a balanced 3-phase conductor assembly as armature in its stator. The armature winding is driven by a power electronics inverter which is operating the switches according to the rotor position, sensed by an optical encoder or a Hall Effect sensor. It is found that by tuning the value of rotor position, no-load condition, and trapezoidal armature phase current, the variation in torque can be minimized. Different performance parameters for no-load and load condition of the BLDC motor like phase voltages and currents, speed, electromagnetic torque, d, q axis current and rotor position etc. are determined in MATLAB environment. These parameter evaluations is necessary to achieve better performance in both load and no load condition of BLDC motor in terms of speed and torque as these are the vital point for the selection of the application field of BLDC motor drive.

Sign in / Sign up

Export Citation Format

Share Document