scholarly journals A Study of Bubble Mineralization by Modified Glass Microspheres Based on a High-Speed Dynamic Microscopic Test System

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 350 ◽  
Author(s):  
Fanfan Zhang ◽  
Yijun Cao ◽  
Xiaokang Yan ◽  
Lijun Wang ◽  
Yajun Xu
Keyword(s):  
Contact Angle ◽  
High Speed ◽  
Functional Group ◽  
Research Process ◽  
Test System ◽  
Glass Microsphere ◽  
Collision Probability ◽  
Glass Microspheres ◽  
Large Glass ◽  
Small Glass

The microscopic study of bubble mineralization is an important means of flotation theory research. In order to visualize the research process, it is required that the particles have certain optical properties and the amount of bubbles is controllable. In this paper, the particles were glass microspheres modified with trimethylchlorosilane (TMCS). The modification effect was confirmed by Fourier-transform infrared spectroscopy (FTIR), contact angle measurements, and a flotation test. The FTIR analysis and flotation test verified that the functional group (-OH) of glass microspheres reacted with the functional group (-Si-Cl) of TMCS and that the glass microsphere surface was successfully modified. The results also showed that the contact angle and hydrophobicity of the glass microspheres of a given size increased with the increase of TMCS. A small glass microsphere required more TMCS during the modification step in order to have the same contact angle as a large glass microsphere. The microscopic process of bubble mineralization was captured by a high-speed dynamic analysis system. The probability of collision between large glass microspheres and bubbles was high, but so was the probability that the microspheres would detach from the bubble. Both the collision probability and the detachment probability between small glass microspheres and bubbles were small, and small glass microspheres were easily affected by the flotation fluid. Besides, small bubbles and fine glass microspheres had a higher flotation recovery than coarse glass microspheres and large bubbles.

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

Contusion, dislocation, and distraction: primary hemorrhage and membrane permeability in distinct mechanisms of spinal cord injury

2007 ◽  
Vol 6 (3) ◽  
pp. 255-266 ◽  
Author(s):  
Anthony M. Choo ◽  
Jie Liu ◽  
Clarrie K. Lam ◽  
Marcel Dvorak ◽  
Wolfram Tetzlaff ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
White Matter ◽  
Animal Models ◽  
Membrane Permeability ◽  
High Speed ◽  
Test System ◽  
Fracture Dislocation ◽  
Sprague Dawley ◽  
Cord Injury

Object In experimental models of spinal cord injury (SCI) researchers have typically focused on contusion and transection injuries. Clinically, however, other injury mechanisms such as fracture–dislocation and distraction also frequently occur. The objective of the present study was to compare the primary damage in three clinically relevant animal models of SCI. Methods Contusion, fracture–dislocation, and flexion–distraction animal models of SCI were developed. To visualize traumatic increases in cellular membrane permeability, fluorescein–dextran was infused into the cerebrospi-nal fluid prior to injury. High-speed injuries (approaching 100 cm/second) were produced in the cervical spine of deeply anesthetized Sprague–Dawley rats (28 SCI and eight sham treated) with a novel multimechanism SCI test system. The animals were killed immediately thereafter so that the authors could characterize the primary injury in the gray and white matter. Sections stained with H & E showed that contusion and dislocation injuries resulted in similar central damage to the gray matter vasculature whereas no overt hemorrhage was detected following distraction. Contusion resulted in membrane disruption of neuronal somata and axons localized within 1 mm of the lesion epicenter. In contrast, membrane compromise in the dislocation and distraction models was observed to extend rostrally up to 5 mm, particularly in the ventral and lateral white matter tracts. Conclusions Given the pivotal nature of hemorrhagic necrosis and plasma membrane compromise in the initiation of downstream SCI pathomechanisms, the aforementioned differences suggest the presence of mechanism-specific injury regions, which may alter future clinical treatment paradigms.

Rotordynamic Performance of a Rotor Supported on Bump Type Foil Gas Bearings: Experiments and Predictions

2006 ◽  
Vol 129 (3) ◽  
pp. 850-857 ◽  
Author(s):  
Luis San Andrés ◽  
Dario Rubio ◽  
Tae Ho Kim
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Load Capacity ◽  
Test System ◽  
Foil Bearings ◽  
Rotor Imbalance ◽  
Synchronous Motion ◽  
Damping Characteristics ◽  
Rotor Surface ◽  
Stiffness And Damping

Gas foil bearings (GFBs) satisfy the requirements for oil-free turbomachinery, i.e., simple construction and ensuring low drag friction and reliable high speed operation. However, GFBs have a limited load capacity and minimal damping, as well as frequency and amplitude dependent stiffness and damping characteristics. This paper provides experimental results of the rotordynamic performance of a small rotor supported on two bump-type GFBs of length and diameter equal to 38.10mm. Coast down rotor responses from 25krpm to rest are recorded for various imbalance conditions and increasing air feed pressures. The peak amplitudes of rotor synchronous motion at the system critical speed are not proportional to the imbalance introduced. Furthermore, for the largest imbalance, the test system shows subsynchronous motions from 20.5krpm to 15krpm with a whirl frequency at ∼50% of shaft speed. Rotor imbalance exacerbates the severity of subsynchronous motions, thus denoting a forced nonlinearity in the GFBs. The rotor dynamic analysis with calculated GFB force coefficients predicts a critical speed at 8.5krpm, as in the experiments; and importantly enough, unstable operation in the same speed range as the test results for the largest imbalance. Predicted imbalance responses do not agree with the rotor measurements while crossing the critical speed, except for the lowest imbalance case. Gas pressurization through the bearings’ side ameliorates rotor subsynchronous motions and reduces the peak amplitudes at the critical speed. Posttest inspection reveal wear spots on the top foils and rotor surface.

Design of an Intelligent Multi-Gyro Measurement Device

2005 ◽  
Vol 295-296 ◽  
pp. 589-594
Author(s):  
J.P. Wang ◽  
W. Zhou ◽  
W.F. Tian ◽  
Z.H. Jin
Keyword(s):  
High Speed ◽  
Dynamic Balance ◽  
Control Unit ◽  
Calibration Method ◽  
Test System ◽  
Measurement Device ◽  
Logic Control ◽  
Hardware Description ◽  
Thermal Resistors ◽  
Inertial Unit

This paper describes the design of an intelligent multi-gyro measurement device to measure and monitor an inertial unit composed of three dynamically tuned gyros (DTGs). A 16-bit microprogrammed control unit is programmed to fulfill the functions of signal processing, logic control and serial communication with a master computer. An FPGA, designed by using Verilog Hardware Description Language, is used to realize high speed 16-bit reversible counters for output pulses of the DTG digital dynamic balance circuits. The count values represent the angular motion of the inertial unit. A stepping electric bridge is employed to measure the resistance of thermal resistors within the gyros in a wide temperature environment. The resistance represents the working temperature of the gyros. An effective calibration method for the bridge is developed to eliminate the resistance measurement error. A test system is established to examine whether the device meets the user requirements. Results of the tests show that the device has a good performance. A trial use has proved that the device is stable and reliable and that it satisfies the demand of the user.

Electron-beam test system for high-speed devices

Scanning ◽  
1987 ◽  
Vol 9 (5) ◽  
pp. 201-204 ◽  
Author(s):  
M. Brunner ◽  
D. Winkler ◽  
R. Schmitt ◽  
B. Lischke
Keyword(s):  
Electron Beam ◽  
High Speed ◽  
Test System ◽  
Beam Test

Experimental Investigation on Contact Angle of Sintered Copper Powder Wick

2016 ◽  
Vol 819 ◽  
pp. 575-579 ◽  
Author(s):  
Nandy Putra ◽  
Iwan Setyawan ◽  
Dimas Raditya
Keyword(s):  
Contact Angle ◽  
Copper Powder ◽  
High Speed ◽  
Ambient Air ◽  
Video Camera ◽  
High Heat ◽  
High Heat Flux ◽  
Powder Particle Size ◽  
Air Exposure ◽  
Sintered Copper

Heat pipes are widely used in electronic cooling and other applications that require efficient transport or spreading of heat from local sources of high heat flux. One factor that most affect the performance of this device is the wetting properties of the wick material, whereby a hydrophilic wick material is required to transport the liquid from the evaporator to the condenser. The performance of heat pipe will decrease when the wick surface becomes hydrophobic as indicated by changes in its contact angle (CA). This study aims to determine the effect of ambient air exposure on the wettability of wick material. Wettability for a surface by a certain liquid can be shown by measuring the contact angle of liquid droplets on the surface. In this experiment, the contact angle was captured using a high speed video camera followed by image processing and then measured using Image J software. The surface of the sample/wick is a sintered copper powder which in this study through a process of forming or compaction by various parameters such as powder particle size, compacting pressure and sintering temperature. From the results of this study was found that the longer wicks were exposed in the ambient air, the contact angle of the liquid on the wick surface will be getting increased. After 7 days were contaminated on the ambient air, then all samples have been turned into hydrophobic, CA>90°.

Test System for Mechanical Property of Geotextile Material Based on PCI-1714

2012 ◽  
Vol 455-456 ◽  
pp. 217-221
Author(s):  
Zhi Gang Liu ◽  
Qi Xiao Sun
Keyword(s):  
Mechanical Property ◽  
Data Acquisition ◽  
High Speed ◽  
Test System ◽  
Overall Design ◽  
Data Acquisition Software ◽  
Mechanics Performance ◽  
Data Acquisition Card ◽  
High Speed Data Acquisition ◽  
High Speed Data

A solution of intelligent test system for mechanical property of geotextile material which based on high speed data acquisition card PCI-1714 is introduced in this paper. Microprocessor and drive card PCI-1240 are also used to control and drive the test equipment. The article discussed in detail the system’s overall design, the hardware structure, software design, and process of data acquisition. Software is designed by Visual Basic 6.0. This paper research and implement on accurate measurement of mechanics performance of geotextile material.

scholarly journals Integrated Durability of Automobile Alternator Test System Design Based on LabVIEW

2014 ◽  
Vol 8 (1) ◽  
pp. 839-845 ◽  
Author(s):  
Wu Weibin ◽  
Feng Yue ◽  
Du Junyi ◽  
Xu Pengbo ◽  
Feng Yunlin ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Automotive Industry ◽  
Virtual Instrument ◽  
Measurement Errors ◽  
High Speed ◽  
Performance Test ◽  
Test System ◽  
Electrical Performance ◽  
Durability Test ◽  
Limit Test

New standards in the automotive industry highlighted the situation of the actual operation of the alternator and a variety of harsh environment simulation limit test. Using new standards in the automotive industry as a guide, this article presents a virtual instrument based on the durability of automobile generator integrated test system. The design adopt virtual instrument technology in designing the system, Graphic language, LabVIEW is applied in writing measure-control program. The system uses a lot of features on LABVIEW, including Data acquisition, control of serials port, etc. Test implementation uses the host computer via RS232 and RS485 communication port and the data acquisition card, NI PCI- 6221, to control the frequency hybrid motor, temperature control box, electronic loads and other intelligent devices, and to simulate a variety of automotive alternator working conditions and real-time monitoring to monitor the status of generators. Using this system, two separate automobile alternators can be tested in terms of high-speed vehicle impact and high temperature durability test and electrical performance test and other tests at the same time. As a result, the generator speed measurement error is within 1%, the control error is within 2%, voltage and current measurement errors were within 0.5% and 0.4%, which meets the requirements.

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