Experimental investigations of advanced ceramics in high efficiency deep grinding

2007 ◽  
Vol 43 (01) ◽  
pp. 176 ◽  
Author(s):  
Guizhi XIE
Keyword(s):  
High Efficiency ◽  
Experimental Investigations ◽  
Advanced Ceramics

scholarly journals Low Power Cusped Field Thruster Developed for the Space-Borne Gravitational Wave Detection Mission in China

2021 ◽  
Vol 11 (14) ◽  
pp. 6549
Author(s):  
Hui Liu ◽  
Ming Zeng ◽  
Xiang Niu ◽  
Hongyan Huang ◽  
Daren Yu
Keyword(s):  
Low Power ◽  
Gravitational Wave ◽  
Attitude Control ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Attitude Control System ◽  
Gravitational Wave Detection ◽  
Wave Detection ◽  
Wide Range ◽  
Institute Of Technology

The microthruster is the crucial device of the drag-free attitude control system, essential for the space-borne gravitational wave detection mission. The cusped field thruster (also called the High Efficiency Multistage Plasma Thruster) becomes one of the candidate thrusters for the mission due to its low complexity and potential long life over a wide range of thrust. However, the prescribed minimum of thrust and thrust noise are considerable obstacles to downscaling works on cusped field thrusters. This article reviews the development of the low power cusped field thruster at the Harbin Institute of Technology since 2012, including the design of prototypes, experimental investigations and simulation studies. Progress has been made on the downscaling of cusped field thrusters, and a new concept of microwave discharge cusped field thruster has been introduced.

scholarly journals Roll Bonding of Al-Based Composite Reinforced with C10 Steel Expanded Mesh Inlay

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1044
Author(s):  
Yaroslav Frolov ◽  
Maxim Nosko ◽  
Andrii Samsonenko ◽  
Oleksandr Bobukh ◽  
Oleg Remez
Keyword(s):  
Impact Energy ◽  
High Efficiency ◽  
Shape Change ◽  
Experimental Investigations ◽  
Aluminum Composite ◽  
Rolling Mills ◽  
Roll Bonding ◽  
Finite Element Software ◽  
Steel Mesh ◽  
Bonded Composite

The most complex issue related to the design of high efficiency composite materials is the behavior of the reinforcing component during the bonding process. This study presents numerical and experimental investigations of the shape change in the reinforcing inlay in an aluminum-steel mesh-aluminum composite during roll-bonding. A flat composite material consisting of two outer strips of an EN AW 1050 alloy and an inlay of expanded C10 steel mesh was obtained via hot roll bonding with nominal rolling reductions of 20%, 30%, 40% and 50% at a temperature of 500 °C. The experimental procedure was carried out using two separate rolling mills with diameters equal to 135 and 200 mm, respectively. A computer simulation of the roll bonding was performed using the finite element software QForm 9.0.10 by Micas Simulations Limited, Oxford, UK. The distortion of the mesh evaluated via the change in angle between its strands was described using computer tomography scanning. The dependence of the absorbed impact energy of the roll bonded composite on the parameters of the deformation zone was found. The results of the numerical simulation of the steel mesh shape change during roll bonding concur with the data from micro-CT scans of the composites. The diameter of rolls applied during the roll bonding, along with rolling reduction and temperature, have an influence on the resulting mechanical properties, i.e., the absorbed bending energy. Generally, the composites with reinforcement exhibit up to 20% higher impact energy in comparison with the non-reinforced composites.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Ultrasonic Vibration-Assisted Laser Engineered Net Shaping of Inconel 718 Parts: Microstructural and Mechanical Characterization

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Fuda Ning ◽  
Yingbin Hu ◽  
Zhichao Liu ◽  
Xinlin Wang ◽  
Yuzhou Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Vibration ◽  
Inconel 718 ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Laser Engineered Net Shaping ◽  
Average Grain Size ◽  
Fabrication Defects ◽  
Heterogeneous Microstructures ◽  
Net Shaping

Laser engineered net shaping (LENS) has become a promising technology in direct manufacturing or repairing of high-performance metal parts. Investigations on LENS manufacturing of Inconel 718 (IN718) parts have been conducted for potential applications in the aircraft turbine component manufacturing or repairing. Fabrication defects, such as pores and heterogeneous microstructures, are inevitably induced in the parts, affecting part qualities and mechanical properties. Therefore, it is necessary to investigate a high-efficiency LENS process for the high-quality IN718 part fabrication. Ultrasonic vibration has been implemented into various melting material solidification processes for part performance improvements. However, there is a lack of studies on the utilization of ultrasonic vibration in LENS process for IN718 part manufacturing. In this paper, ultrasonic vibration-assisted (UV-A) LENS process is, thus, proposed to fabricate IN718 parts for the potential reduction of fabrication defects. Experimental investigations are conducted to study the effects of ultrasonic vibration on microstructures and mechanical properties of LENS-fabricated parts under two levels of laser power. The results showed that ultrasonic vibration could reduce the mean porosity to 0.1%, refine the microstructure with an average grain size of 5 μm, and fragment the detrimental Laves precipitated phase into small particles in a uniform distribution, thus enhancing yield strength, ultimate tensile strength (UTS), microhardness, and wear resistance of the fabricated IN718 parts.

Design and HIL Validation of an Effective Super-Twisting Controller for Stick-Slip Suppression in Drill-String Systems

2021 ◽  
Author(s):  
Abdelbasset Krama ◽  
Mohamed Gharib ◽  
Shady S. Refaat ◽  
Alan Palazzolo
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Sliding Mode ◽  
Drill String ◽  
Experimental Investigations ◽  
Small Scale ◽  
Oil Well ◽  
Stick Slip ◽  
Rock Interaction ◽  
The Real

Abstract This paper presents a novel controller for drill string systems based on a super-twisting sliding mode theory. The aim is to eliminate the stick-slip vibration and maintain a constant drill string velocity at the desired reference value. The proposed controller inherently attenuates the torsional vibration while ensuring the stability and high efficiency of the drill string. A discontinuous lumped-parameter torsional model of vertical drill strings based on four components (rotary table, drill pipes, drill collars and drill bit) is considered. The Karnopp friction model is adopted to simulate the nonlinear bit-rock interaction phenomena. In order to provide a more accurate evaluation, the proposed drill string controller is implemented with the induction motor, a variable frequency drive and a gearbox to closely mirror the real environment of oil well drill strings. The increasing demand for prototyping and testing high-power plants in realistic and safe environments has led to the advancement of new types of experimental investigations without hurting the real system or building a small-scale prototype for testing. The dynamic performance of the proposed controller has been investigated with MATLAB software as well as in a novel hardware in-the-loop (HIL) testing platform. A power plant is modeled and implemented in the real-time simulator OPAL-RT 5600, whereas the controllers are implemented in the dSPACE 1103 control board. The results obtained through simulation and HIL testing demonstrate the feasibility and high performance of the proposed controller.

Toward 20% Efficiency With a-Si // poly-Si Tandem Solar Cell

1992 ◽  
Vol 258 ◽  
Author(s):  
M. Yoshimi ◽  
W. Ma ◽  
T. Horiuchi ◽  
C. C. Lim ◽  
S. C. De ◽  
...  
Keyword(s):  
Solar Cell ◽  
High Efficiency ◽  
Low Cost ◽  
Cell Structure ◽  
Experimental Investigations ◽  
Total Efficiency ◽  
Tandem Solar Cell ◽  
Structure Variation ◽  
Technical Data ◽  
Bottom Cell

ABSTRACTA series of experimental investigations has been made on the a-Si // poly-Si tandem solar cell which is one of the most promised candidate of high cost-performance photovoltaic cell, e.g., high efficiency, low cost with almost no light induced degradation. Employing high conductivity with wide optical band gap p type microcrystalline SiC (μ-SiC) as a window material together with a-SiC as an interface buffer layer and also n type μc-Si as a back ohmic contact layer in the poly-Si based bottom cell, the conversion efficiency of 17.2 % has been obtained. Combining an optically transparent a-Si p-i-n cell as a top cell with an optical coupler between the top and the poly-Si bottom cell, a total efficiency of 20.3 % has been obtained so far on the four-terminal stacked mode structure. A systematic technical data for the optimization of cell structure variation on the developed tandem solar cells are presented and further possibility to improving the performance are discussed.

Adaptable pneumatic shock absorber

2018 ◽  
Vol 25 (3) ◽  
pp. 711-721 ◽  
Author(s):  
Rami Faraj ◽  
Cezary Graczykowski ◽  
Jan Holnicki-Szulc
Keyword(s):  
Active Control ◽  
Smart Materials ◽  
Shock Absorber ◽  
High Efficiency ◽  
Low Cost ◽  
Electronic System ◽  
Experimental Investigations ◽  
Adaptation Mechanism ◽  
Impact Absorption ◽  
Pneumatic Shock

Recent progress in the field of sensors, actuators, and smart materials allows the construction of more and more efficient controllable pneumatic dampers for shock absorption. Typically, such devices apply online semi-active control techniques, which utilize electromagnetic, piezoelectric, or magnetostrictive valves. As a result, they are characterized by a high efficiency of impact absorption, but simultaneously by a complicated construction and a specialized electronic system. The alternative solutions are semi-passive absorbers that ensure a similar performance by using a much simpler, low-cost construction and a less complicated adaptation mechanism. This paper introduces an adaptable semi-passive single-chamber pneumatic shock absorber, SOFT-DROP, which provides the optimal impact absorption and energy dissipation after a single reconfiguration performed at the beginning of the process. The high effectiveness of the proposed concept is proved in numerical and experimental investigations of the device. Moreover, the proposed semi-passive damper is also compared against already known pneumatic absorbers that utilize semi-active control methods. Ultimately, the device might be used in an airdrop system for delivery of light packages.

scholarly journals Nonequlibrium Plasma Chemistry for Concept of Sustainable Development

2017 ◽  
Vol 4 (2) ◽  
pp. 141-144
Author(s):  
V. Chernyak ◽  
O. Nedybaliuk ◽  
O. Tsymbaliuk ◽  
I. Fedirchyk ◽  
K. Chunikhina ◽  
...  
Keyword(s):  
Sustainable Development ◽  
High Efficiency ◽  
Plasma Chemistry ◽  
Catalytic Conversion ◽  
Experimental Investigations ◽  
Liquid Hydrocarbons ◽  
Hybrid Plasma

This work is devoted to the exploration of the compatibility of the hybrid plasma-catalytic conversion of liquid hydrocarbons into syngas with the concept of sustainable development. The results of experimental investigations indicate the high efficiency of plasma-catalytic conversion of ethanol to syngas and the small amount of waste (a few percent of feedstock weight). The results of the simulation of the kinetics using ZDPlasKin code for thermochemical and hybrid plasma-catalytic conversion.

Method and Device of Pyrolytic Processing of Pulp and Paper Industry’ Waste into High-Quality Synthesis Gas

2018 ◽  
Vol 22 (11) ◽  
pp. 4-9
Author(s):  
V.M. Zaitchenko ◽  
K.O. Krysanova ◽  
V.A. Lavrenov
Keyword(s):  
Synthesis Gas ◽  
High Efficiency ◽  
Paper Industry ◽  
Fixed Bed ◽  
Pulp And Paper Industry ◽  
Processing Parameters ◽  
Pulp And Paper ◽  
Raw Material ◽  
Experimental Investigations ◽  
High Quality

Paper presents the results of the experimental investigations of the pulp and paper industry’ wood waste processing method into high-quality synthesis gas. The main characteristics of feedstock (moisture and ash content, elemental composition, higher and lower heating values, volatile matter and fixed carbon content) and synthesis gas (yield, chemical composition, heating value and tar content) in dependence of the processing parameters are described. Processing is carried out by the two-stage pyrolytic conversion method, combining pyrolysis and subsequent high-temperature cracking of volatiles in the charcoal fixed bed. The principal scheme and results of the thermotechnical characteristics calculation of the pilot plant capacity of 300 kg/h of raw material (mechanical mixture of wood chips and bark with a moisture content of 48 %) are presented. The obtained results confirm the high efficiency of the method as applied to the processing of this type of waste.

Theoretical Aspects of Construction of Turning up and Loading Machine with Disinfection Option for Agricultural Waste by Carbon Nanostructures Modified Sodium Acetate

2017 ◽  
Vol 13 ◽  
pp. 130-134 ◽  
Author(s):  
Alexandr V. Shchegolkov ◽  
Boris S. Trufanov ◽  
Victor D. Hmyrov ◽  
Vyacheslav B. Kudenko ◽  
Yulia V. Guryanova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Sodium Acetate ◽  
High Efficiency ◽  
New Technology ◽  
Agricultural Waste ◽  
Experimental Investigations ◽  
Structural Elements ◽  
Theoretical Substantiation ◽  
Processed Waste

The present paper describes the results of the use of new technology of disinfection and processing of agricultural waste by carbon nanostructures modified sodium acetate. Improving the efficiency of processing of agricultural waste was obtained via sodium acetate in the presence of carbon nanotubes. In order to distribute the sodium acetate in the processed waste and subsequent processing of waste effectively special machines/devices were developed. The theoretical substantiation of the basic structural elements was presented for mechanical processing of agricultural waste devices. The experimental investigations showed a high efficiency of technology which led to a reduction of pathogens at the pre-processing of manure by 60%. The consumption of sodium acetate with carbon nanotubes was 50 liters per 1 ton of manure.

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