CFD Analysis in a Non-Contact Holder

2011 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
Shinsuke Katsumata
Keyword(s):  
High Efficiency ◽  
Air Flow ◽  
Low Pressure ◽  
The Body ◽  
Systematic Research ◽  
Work Piece ◽  
Cfd Analysis ◽  
Pressure Distributions ◽  
Air Jet ◽  
Pressure Region

There are many devices that use air flow characteristics. Recently an electric fan without propeller using air jet flow and a vacuum cleaner using swirling air flow have been developed by Dyson Ltd. Furthermore, as one of the applications of such air flow, a non-contact holder that can hold a body such as a work piece, disc etc., using low-pressure region generated by air flow without contact was developed by a Japanese company. Some bodies such as work piece are brought without contact with the holder. The mechanism to hold them is explained by Bernoulli’s theorem. However, systematic research has not been done in the present stage and the effect of the geometry of the non-contact holder on the holding force is not clear. In this paper, we calculated the flow in a non-contact holder and obtained the force to hold a body by CFD analysis. The effect of the deflector and inside geometry of the holder on the velocity and pressure distribution, and holding force is investigated. The deflector is a device fixed with the holder to increase the holding force using low-pressure region. CFD was done using both incompressible and compressible flow, and k-ε turbulent model was used. The calculated pressure distributions of a simpler model of the holder are compared with the previous experimental results to confirm our calculation method. The design policy of a non-contact holder is discussed based on the calculated results of velocity and pressure distributions and holding force. Consequently we show that the deflector is very useful to obtain high holding force and the concept to design the non-contact holder is required to get the holding force according to the weight of the body and to achieve high efficiency.

Experimental Study and CFD Analysis of the Volumatic® Spacer

2008 ◽  
Author(s):  
Sofia Abreu ◽  
Lui´s Silva ◽  
Senhorinha F. C. F. Teixeira ◽  
Henedina Antunes ◽  
Helena Marques ◽  
...  
Keyword(s):  
Experimental Study ◽  
Air Flow ◽  
The Body ◽  
Respiratory Cycle ◽  
Cfd Analysis ◽  
Aerosol Flow

The aim of the present study was to evaluate the performance of Ventilan® coupled to the Volumatic® spacer. An experimental study was conducted using the four stage Multistage Liquid Impinger (MSLI). This enabled the observation that half of the pharmacological dose is retained within the body of the spacer. Therefore, the air flow inside the spacer was studied, along the respiratory cycle, using Fluent™. Several recirculation regions were observed inside the spacer that may influence the aerosol flow and also the deposition of the drug.

Research on Wear and Life Prediction of Hobbing Cutter in Cryogenic Cutting with MQL

2012 ◽  
Vol 430-432 ◽  
pp. 842-848
Author(s):  
Xiao Hong Zhang ◽  
Chong Xia ◽  
Peng Chen ◽  
Guo Fu Yin
Keyword(s):  
Air Temperature ◽  
Life Prediction ◽  
Air Flow ◽  
Work Piece ◽  
Air Jet ◽  
Rotary Speed ◽  
Bp Model ◽  
The Given ◽  
Cryogenic Cutting ◽  
Total Life

An ANN BP model is built to imitate the relative between output, the wear of hobbing cutter, and input, such as rotary speed of cutter, air flow, air jet speed, air temperature, situation of hobbing cutter and hardness of work piece. A program is compiled to extrapolate the total life of hobbing cutter based on the BP model. The conclusion can be obtained by the program about the total life of hobbing cutter in cryogenic cutting with MQL, as follow. When parameters vary in the given zone, air jet speed has the largest effect on the total life of hobbing cutter by 23.8%, and follows the air flow by 13.5%, and last is the air temperature by 4.4%.

Inspector Quadro - the complex of preparation for the treatment of ectoand endoparasitoses in cats and dogs

2018 ◽  
Vol 12 (2) ◽  
pp. 75-84
Author(s):  
M.V. Arisov ◽  
I.P. Belykh ◽  
V.V. Artemov
Keyword(s):  
Body Weight ◽  
Clinical Picture ◽  
High Efficiency ◽  
The Body ◽  
Negative Effects ◽  
Laboratory Methods ◽  
Diagnosis Of Infection

The purpose of the research: the study of the efficacy of the preparations for veterinary use "Inspector Quadro C" and "Inspector Quadro K" against ecto- and endoparasitoses of dogs and cats. Materials and methods. Studies were conducted on spontaneously infected dogs and cats of different sexes, age, weight and breed. The diagnosis of infection with ectoparasites was made based on the clinical picture and laboratory methods of investigation (microscopy of scrapings taken from ectoparasitized skin areas, examination of the coat for fleas, lice, worms, ixodids). Infection with helminths was established by detecting eggs of helminths in faeces of animals by the method of Füleleborn and mature segments of cestodes. Preparations were applied to the animals by drip application on dry undamaged skin in places inaccessible to licking in a dose of 0.1-0.4 ml per 1 kg of body weight. The results were statistically processed. Results and discussion. "Inspector Quadro S" and "Inspector Quadro K" showed 100% efficacy at sarcoptosis in dogs, notoedrosis in cats, otodectosis in dogs and cats, ixodidoses and entomoses. "Inspector Quadro C" showed a high efficiency (92.3%) at demodecosis in dogs. However, single mites were found in one dog. 100% efficacy of "Inspector Quadro C" and "Inspector Quadro K" has been established against intestinal nematodes and cestodes in dogs and cats. Negative effects of drugs on the body of animals have not been revealed.

RHELP (Regenerative High Efficiency Low Pressure) Air Purification System

2009 ◽  
Author(s):  
Chang-Yu Wu ◽  
Brian Damit ◽  
Qi Zhang ◽  
Myung-Heui Woo ◽  
Wolfgang Sigmund ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Pressure ◽  
Air Purification ◽  
Purification System

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

Research on the methods and means of action strength training in aerobics training

2021 ◽  
pp. 002072092110042
Author(s):  
Xiaona Yang ◽  
Yang Ji ◽  
Da Ke ◽  
Fang Li
Keyword(s):  
Strength Training ◽  
Team Member ◽  
High Efficiency ◽  
Colleges And Universities ◽  
The Body ◽  
Energy Output ◽  
Control Group ◽  
Experimental Sample ◽  
Training Method ◽  
Core Strength

Aerobics is a beautiful and rhythmic sport. In recent years, aerobics has developed rapidly, and has become one of the essential courses of physical education in Colleges and universities. But the existing aerobics courses in Colleges and universities are less involved in the training process of action strength. Lack of strength quality is a common shortcoming of Aerobics Athletes in Colleges and universities. Therefore, this paper puts forward the methods and means of action strength training in aerobics training. According to the characteristics of competitive aerobics, combined with the traditional training strategy of action strength, this paper formulates the method of action strength training suitable for College Aerobics athletes. In order to further verify the effectiveness of this method, this paper takes a university aerobics team as an experimental sample to carry out a comparative analysis of the effect of action strength training. Relevant studies have proved that core strength training has the following effects on aerobics players: 1. Helps the calisthenics team member stabilize the trunk, improve the body's control ability and balance ability. 2. It is conducive to completing difficult movements of calisthenics with high efficiency and low energy consumption. 3. Helps the aerobics team member to enhance the special strength. 4. It can effectively prevent sports injuries. 5. It can improve the direction change and displacement speed of the body. 6. It can improve the energy output of the core strength to the limbs and other muscle groups during movement, so that the movement can be completed more perfectly.According to the results of the experiment, the explosive force and endurance of the experimental group after 8 weeks of training have been significantly improved, and formed a more obvious difference with the control group. The aerobics training method developed in this paper can be divided into two stages: the initial stage and the middle stage, which can better meet the students with different physical qualities. At the end of this paper, a fast strength training method is introduced, and the characteristics of different training methods are analyzed.

scholarly journals A High Efficiency Low Noise RF-to-DC Converter Employing Gm-Boosting Envelope Detector and Offset Canceled Latch Comparator

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Thi Thuy Pham ◽  
Dongmin Kim ◽  
Seo-Hyeong Jeong ◽  
Junghyup Lee ◽  
Donggu Im
Keyword(s):  
Power Consumption ◽  
High Efficiency ◽  
Supply Voltage ◽  
Current Source ◽  
Low Noise ◽  
The Body ◽  
Common Source ◽  
Conversion Gain ◽  
Input Transistor ◽  
Envelope Detector

This work presents a high efficiency RF-to-DC conversion circuit composed of an LC-CL balun-based Gm-boosting envelope detector, a low noise baseband amplifier, and an offset canceled latch comparator. It was designed to have high sensitivity with low power consumption for wake-up receiver (WuRx) applications. The proposed envelope detector is based on a fully integrated inductively degenerated common-source amplifier with a series gate inductor. The LC-CL balun circuit is merged with the core of the envelope detector by sharing the on-chip gate and source inductors. The proposed technique doubles the transconductance of the input transistor of the envelope detector without any extra power consumption because the gate and source voltage on the input transistor operates in a differential mode. This results in a higher RF-to-DC conversion gain. In order to improve the sensitivity of the wake-up radio, the DC offset of the latch comparator circuit is canceled by controlling the body bias voltage of a pair of differential input transistors through a binary-weighted current source cell. In addition, the hysteresis characteristic is implemented in order to avoid unstable operation by the large noise at the compared signal. The hysteresis window is programmable by changing the channel width of the latch transistor. The low noise baseband amplifier amplifies the output signal of the envelope detector and transfers it into the comparator circuit with low noise. For the 2.4 GHz WuRx, the proposed envelope detector with no external matching components shows the simulated conversion gain of about 16.79 V/V when the input power is around the sensitivity of −60 dBm, and this is 1.7 times higher than that of the conventional envelope detector with the same current and load. The proposed RF-to-DC conversion circuit (WuRx) achieves a sensitivity of about −65.4 dBm based on 45% to 55% duty, dissipating a power of 22 μW from a 1.2 V supply voltage.

scholarly journals Enhanced Performance and Diffusion Robustness of Phase-Change Metasurfaces via a Hybrid Dielectric/Plasmonic Approach

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 525
Author(s):  
Joe Shields ◽  
Carlota Ruiz de Galarreta ◽  
Jacopo Bertolotti ◽  
C. David Wright
Keyword(s):  
Melting Point ◽  
Phase Change ◽  
Noble Metals ◽  
Phase Change Materials ◽  
High Efficiency ◽  
The Body ◽  
Design Stage ◽  
High Melting ◽  
Optical Performance ◽  
Electrical Conductors

Materials of which the refractive indices can be thermally tuned or switched, such as in chalcogenide phase-change alloys, offer a promising path towards the development of active optical metasurfaces for the control of the amplitude, phase, and polarization of light. However, for phase-change metasurfaces to be able to provide viable technology for active light control, in situ electrical switching via resistive heaters integral to or embedded in the metasurface itself is highly desirable. In this context, good electrical conductors (metals) with high melting points (i.e., significantly above the melting point of commonly used phase-change alloys) are required. In addition, such metals should ideally have low plasmonic losses, so as to not degrade metasurface optical performance. This essentially limits the choice to a few noble metals, namely, gold and silver, but these tend to diffuse quite readily into phase-change materials (particularly the archetypal Ge2Sb2Te5 alloy used here), and into dielectric resonators such as Si or Ge. In this work, we introduce a novel hybrid dielectric/plasmonic metasurface architecture, where we incorporated a thin Ge2Sb2Te5 layer into the body of a cubic silicon nanoresonator lying on metallic planes that simultaneously acted as high-efficiency reflectors and resistive heaters. Through systematic studies based on changing the configuration of the bottom metal plane between high-melting-point diffusive and low-melting-point nondiffusive metals (Au and Al, respectively), we explicitly show how thermally activated diffusion can catastrophically and irreversibly degrade the optical performance of chalcogenide phase-change metasurface devices, and how such degradation can be successfully overcome at the design stage via the incorporation of ultrathin Si3N4 barrier layers between the gold plane and the hybrid Si/Ge2Sb2Te5 resonators. Our work clarifies the importance of diffusion of noble metals in thermally tunable metasurfaces and how to overcome it, thus helping phase-change-based metasurface technology move a step closer towards the realization of real-world applications.

Unprecedented CO2 adsorption behaviour by 5A-type zeolite discovered in lower pressure region and at 300 K

2021 ◽  
Author(s):  
Akira Oda ◽  
Suguru Hiraki ◽  
Eiji Harada ◽  
Ikuka Kobayashi ◽  
Takahiro Ohkubo ◽  
...  
Keyword(s):  
Pressure Range ◽  
Co2 Adsorption ◽  
Low Pressure ◽  
Lower Pressure ◽  
Dft Studies ◽  
Adsorption Behaviour ◽  
Zeolite Sample ◽  
Pressure Region ◽  
Type Zeolite ◽  
Efficient Adsorbent

The NaCaA-85 zeolite sample which works as an efficient adsorbent for CO2 at RT and in low pressure range was found and its specificity is nicely explained by the model composed of CO2 pinned by two types of Ca2+ ions through far-IR and DFT studies.

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