Fouling Removal Technology with Intermittent Rotation Spiral-Insert

2012 ◽  
Vol 535-537 ◽  
pp. 2252-2256
Author(s):  
Tian Lan Yu ◽  
De Qi Peng ◽  
Tian Xiang Yu ◽  
Bin Deng ◽  
Yang Ping Liu ◽  
...  
Keyword(s):  
Simple Structure ◽  
Low Cost ◽  
Enhancement Effect ◽  
Transfer Enhancement ◽  
Rotating Speed ◽  
Turbine Condenser ◽  
Continuous Rotation ◽  
Removal Technology ◽  
Series Of Experiments ◽  
Cleaning Technology

An intermittent rotation steel spiral automatic cleaning technology has been developed to address the fouling problem of the condenser tubes in small turbines. The intermittent rotation structure reduces steel spiral rotating speed to less than 1/10 of the continuous rotation spiral, which solves the wearing problems between the spiral and the tube. The results of a series of experiments showed that: the proposed technology meets the requirements of cleaning the hard fouling, and the heat transfer enhancement effect is significantly improved. The technology’s simple structure and low cost are suitable for heat exchangers with inside-tube velocity higher than 1 m / s, especially suitable for turbine condenser.

scholarly journals Design, Analysis, and Experiment on a Novel Stick-Slip Piezoelectric Actuator with a Lever Mechanism

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 863 ◽  
Author(s):  
Weiqing Huang ◽  
Mengxin Sun
Keyword(s):  
Piezoelectric Actuator ◽  
Simple Structure ◽  
Fast Response ◽  
Displacement Sensor ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Stick Slip ◽  
Lever Mechanism ◽  
Series Of Experiments ◽  
Stator Design

A piezoelectric actuator using a lever mechanism is designed, fabricated, and tested with the aim of accomplishing long-travel precision linear driving based on the stick-slip principle. The proposed actuator mainly consists of a stator, an adjustment mechanism, a preload mechanism, a base, and a linear guide. The stator design, comprising a piezoelectric stack and a lever mechanism with a long hinge used to increase the displacement of the driving foot, is described. A simplified model of the stator is created. Its design parameters are determined by an analytical model and confirmed using the finite element method. In a series of experiments, a laser displacement sensor is employed to measure the displacement responses of the actuator under the application of different driving signals. The experiment results demonstrate that the velocity of the actuator rises from 0.05 mm/s to 1.8 mm/s with the frequency increasing from 30 Hz to 150 Hz and the voltage increasing from 30 V to 150 V. It is shown that the minimum step distance of the actuator is 0.875 μm. The proposed actuator features large stroke, a simple structure, fast response, and high resolution.

scholarly journals Investigation of serial coherent laser beam combination based on Brillouin amplification

2007 ◽  
Vol 25 (1) ◽  
pp. 79-83 ◽  
Author(s):  
SHUANGYI WANG ◽  
ZHIWEI LÜ ◽  
DIANYANG LIN ◽  
LEI DING ◽  
DONGBIN JIANG
Keyword(s):  
Laser Beam ◽  
High Power ◽  
Simple Structure ◽  
Low Cost ◽  
Coupling Efficiency ◽  
Laser Beams ◽  
Beam Combination ◽  
Multiple Beams ◽  
Combination Scheme ◽  
Stokes Beam

Based on transferring energy from multiple pump beams into one Stokes beam using Brillouin amplification, a serial coherent laser beam combination scheme is presented, which has many advantages, such as, simple structure, low cost, ease of adjustment, higher load capability, scalable easily, etc. Furthermore, it has been demonstrated that the combination of several beams using this method is theoretically possible. But in practice, the amplification of high power Stokes beam is a key problem to solve. In this paper, the amplification of Stokes beam whose power is higher than the pump beam is first studied and proved experimentally. Coupling the two laser beams by this method is proved experimentally, and the coupling efficiency reaches more than 80%. Then the feasibility of multiple beams combination based on Brillouin amplification is analyzed and tested theoretically.

Compact Triple/Quadruple-Band Reconfigurable Monopole Antenna for Wireless Applications

2021 ◽  
pp. 2150277
Author(s):  
Asmaa Zugari ◽  
Wael Abd Ellatif Ali ◽  
Mohammad Ahmad Salamin ◽  
El Mokhtar Hamham
Keyword(s):  
Simple Structure ◽  
Low Cost ◽  
Ground Plane ◽  
Monopole Antenna ◽  
Pin Diode ◽  
Wireless Applications ◽  
Rectangular Patch ◽  
Antenna Performance ◽  
Compact Size ◽  
Multi Band

In this paper, a compact reconfigurable tri-band/quad-band monopole antenna is presented. To achieve the multi-band behavior, two right-angled triangles were etched in a conventional rectangular patch, and a partial ground plane is used. Moreover, the proposed multi-band antenna is printed on a low cost FR4 epoxy with compact dimensions of 0.23[Formula: see text], where [Formula: see text] is calculated at the lowest resonance frequency. To provide frequency agility, a metal strip which acts as PIN diode was embedded in the frame of the modified patch. The tri-band/quad-band antenna performance in terms of reflection coefficient, radiation patterns, peak gain and efficiency was studied. The measured results are consistent with the simulated results for both cases. The simple structure and the compact size of the proposed antenna could make it a good candidate for multi-band wireless applications.

Simplified rat intubation using a new oropharyngeal intubation wedge

2000 ◽  
Vol 89 (5) ◽  
pp. 1766-1770 ◽  
Author(s):  
I-Ming Jou ◽  
Ya-Ting Tsai ◽  
Ching-Lin Tsai ◽  
Ming-Ho Wu ◽  
Han-Yu Chang ◽  
...  
Keyword(s):  
Low Cost ◽  
Vital Signs ◽  
Upper Airway ◽  
Postmortem Examination ◽  
Normal Range ◽  
Special Equipment ◽  
Vocal Cords ◽  
Oropharyngeal Cavity ◽  
Series Of Experiments ◽  
Proper Setting

Our new oropharyngeal intubation wedge made from a plastic 3-ml syringe has been used successfully for the expansion of the oropharyngeal cavity and visualization of vocal cords for endotracheal intubation in the rat. All the animals we used tolerated the intubation and ventilation procedures in a series of experiments. After the proper setting of the respirator, vital signs were maintained within normal range. The postmortem examination and measurements in the upper airway confirmed that the endotracheal tube was properly sited and also demonstrated the precise size of the device that should be used. The main advantages of this method include low cost, simplicity, and reliability. Furthermore, because no expensive, elaborate, difficult-to-operate, or hard-to-get special equipment is needed, this technique can be used in every laboratory.

scholarly journals Multi-Target Detection Method Based on Variable Carrier Frequency Chirp Sequence

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3386 ◽  
Author(s):  
Wei Wang ◽  
Jinsong Du ◽  
Jie Gao
Keyword(s):  
Intelligent Transportation Systems ◽  
Simple Structure ◽  
Low Cost ◽  
Doppler Frequency ◽  
Transportation Systems ◽  
Practical Application ◽  
Frequency Aliasing ◽  
Application Requirements ◽  
Relationship Of ◽  
Cw Radar

Continuous waveform (CW) radar is widely used in intelligent transportation systems, vehicle assisted driving, and other fields because of its simple structure, low cost and high integration. There are several waveforms which have been developed in the last years. The chirp sequence waveform has the ability to extract the range and velocity parameters of multiple targets. However, conventional chirp sequence waveforms suffer from the Doppler ambiguity problem. This paper proposes a new waveform that follows the practical application requirements, high precision requirements, and low system complexity requirements. The new waveform consists of two chirp sequences, which are intertwined to each other. Each chirp signal has the same frequency modulation, the same bandwidth and the same chirp duration. The carrier frequencies are different and there is a frequency shift which is large enough to ensure that the Doppler frequencies for the same moving target are different. According to the sign and numerical relationship of the Doppler frequencies (possibly frequency aliasing), the Doppler frequency ambiguity problem is solved in eight cases. Theoretical analysis and simulation results verify that the new radar waveform is capable of measuring range and radial velocity simultaneously and unambiguously, with high accuracy and resolution even in multi-target situations.

scholarly journals Application of Alber's principle to develop a device supporting wheelchair in stair climbing

2013 ◽  
Vol 16 (2) ◽  
pp. 5-12
Author(s):  
Nghin Van Dang ◽  
Co Pham ◽  
Thong Hoang Pham ◽  
Phuc Dang Ho
Keyword(s):  
Simple Structure ◽  
Low Cost ◽  
Total Weight ◽  
Stair Climbing ◽  
Disabled People ◽  
And Control ◽  
Climbing Stairs

This paper presents developing Alber principle for machine supporting wheelchair in climbing stairs. The designed machine can support wheelchair and disabled people with total weight 80 kg climb up and down most of stairs and with speed 10-15 stairs per minute. Moving wheelchair and disabled people need assistant person who will hold handle and control the machine. The machine is designed with a simple structure, manufactured with low cost and simple controlling. Therefore the machine can be upgraded and manufactured in future.

scholarly journals Technical Note: Effect of varying the <i>λ</i> = 185 and 254 nm photon flux ratio on radical generation in oxidation flow reactors

2020 ◽  
Vol 20 (21) ◽  
pp. 13417-13424
Author(s):  
Jake P. Rowe ◽  
Andrew T. Lambe ◽  
William H. Brune
Keyword(s):  
Residence Time ◽  
Low Cost ◽  
Flux Ratio ◽  
Technical Note ◽  
Photon Flux ◽  
Oh Radicals ◽  
Flow Reactors ◽  
Series Of Experiments ◽  
Radical Generation ◽  
Smog Chambers

Abstract. Oxidation flow reactors (OFRs) complement environmental smog chambers as a portable, low-cost technique for exposing atmospheric compounds to oxidants such as ozone (O3), nitrate (NO3) radicals, and hydroxyl (OH) radicals. OH is most commonly generated in OFRs via photolysis of externally added O3 at λ=254 nm (OFR254) or combined photolysis of O2 and H2O at λ=185 nm plus photolysis of O3 at λ=254 nm (OFR185) using low-pressure mercury (Hg) lamps. Whereas OFR254 radical generation is influenced by [O3], [H2O], and photon flux at λ=254 nm (I254), OFR185 radical generation is influenced by [O2], [H2O], I185, and I254. Because the ratio of photon fluxes, I185:I254, is OFR-specific, OFR185 performance varies between different systems even when constant [H2O] and I254 are maintained. Thus, calibrations and models developed for one OFR185 system may not be applicable to another. To investigate these issues, we conducted a series of experiments in which I185:I254 emitted by Hg lamps installed in an OFR was systematically varied by fusing multiple segments of lamp quartz together that either transmitted or blocked λ=185 nm radiation. Integrated OH exposure (OHexp) values achieved for each lamp type were obtained using the tracer decay method as a function of UV intensity, humidity, residence time, and external OH reactivity (OHRext). Following previous related studies, a photochemical box model was used to develop a generalized OHexp estimation equation as a function of [H2O], [O3], and OHRext that is applicable for I185:I254≈0.001 to 0.1.

Low Cost Vibration Measurement and Optimization during Turning Process

2018 ◽  
Vol 1148 ◽  
pp. 103-108 ◽  
Author(s):  
N.V.S. Shankar ◽  
A. Gopi Chand ◽  
K. Hanumantha Rao ◽  
K. Prem Sai
Keyword(s):  
Surface Roughness ◽  
Cutting Tool ◽  
Low Cost ◽  
Machining Process ◽  
Vibration Measurement ◽  
Depth Of Cut ◽  
Turning Process ◽  
Taguchi Analysis ◽  
Series Of Experiments

During machining any material, vibrations play a major role in deciding the life of the cutting tool as well as machine tool. The magnitude acceleration of vibrations is directly proportional to the cutting forces. In other words, if we are able to measure the acceleration experienced by the tool during machining, we can get a sense of force. There are many commercially available, pre-calibrated accelerometer sensors available off the shelf. In the current work, an attempt has been made to measure vibrations using ADXL335 accelerometer. This accelerometer is interfaced to computer using Arduino. The measured values are then used to optimize the machining process. Experiments are performed on Brass. During machining, it is better to have lower acceleration values. Thus, the first objective of the work is to minimize the vibrations. Surface roughness is another major factor which criterion “lower is the better” applies. In order to optimize the values, a series of experiments are conducted with three factors, namely, tool type (2 levels), Depth of cut (3 levels) and Feed are considered (3 levels). Mixed level optimization is performed using Taguchi analysis with L18 orthogonal array. Detailed discussion of the parameters shall be given in the article.

Convective heat transfer enhancement: effect of multi-frequency heating

2019 ◽  
Vol 29 (10) ◽  
pp. 3822-3856 ◽  
Author(s):  
Nirmal Kumar Manna ◽  
Nirmalendu Biswas ◽  
Pallab Sinha Mahapatra
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Enhancement ◽  
Convection Heat Transfer ◽  
Enhancement Effect ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Transfer Enhancement ◽  
Content Type ◽  
Frequency Heating

Purpose This study aims to enhance natural convection heat transfer for a porous thermal cavity. Multi-frequency sinusoidal heating is applied at the bottom of a porous square cavity, considering top wall adiabatic and cooling through the sidewalls. The different frequencies, amplitudes and phase angles of sinusoidal heating are investigated to understand their major impacts on the heat transfer characteristics. Design/methodology/approach The finite volume method is used to solve the governing equations in a two-dimensional cavity, considering incompressible laminar flow, Boussinesq approximation and Brinkman–Forchheimer–Darcy model. The mean-temperature constraint is applied for enhancement analysis. Findings The multi-frequency heating can markedly enhance natural convection heat transfer even in the presence of porous medium (enhancement up to ∼74 per cent). Only the positive phase angle offers heat transfer enhancement consistently in all frequencies (studied). Research limitations/implications The present research idea can usefully be extended to other multi-physical areas (nanofluids, magneto-hydrodynamics, etc.). Practical implications The findings are useful for devices working on natural convection. Originality/value The enhancement using multi-frequency heating is estimated under different parametric conditions. The effect of different frequencies of sinusoidal heating, along with the uniform heating, is collectively discussed from the fundamental point of view using the average and local Nusselt number, thermal and hydrodynamic boundary layers and heatlines.

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