scholarly journals Performance Change of Quench Oils Due to Heat and Oxidative Deterioration

2019 ◽  
Author(s):  
Takahito Sugiura ◽  
Katsumi Ichitani ◽  
Greg Steiger
Keyword(s):  
Laboratory Setting ◽  
Cooling Performance ◽  
Base Oil ◽  
Long Period ◽  
Brightness Level ◽  
Performance Change ◽  
Oxidative Deterioration ◽  
And Performance ◽  
The Stability

Abstract Quench oils are used according to needed qualities such as quench hardness, distortion, and appearance. However properties and performance of quench oils may change due to heat and oxidative deterioration. In addition, the properties and performance changes due to heat and oxidative deterioration also differ depending on the types of base oil and additives used in the formulation of the quench oil. In order to use quench oils for a long period, it is necessary to grasp the properties and performance changes within a quench oil due to heat and oxidative deterioration.In this study, we investigated how heat and oxidative deterioration changes of dark and transparent quench oils. We accelerated the heat and oxidation deterioration testing to determine the performance change of the quench oils and investigate if there is a correlation with the deterioration tendency of quench oils in a laboratory setting versus actual quench furnace usage In conclusion, in the transparent type, the brightness is better compared to the dark type of quench oil. While the cooling performance in transparent oils decrease because the vapor blanket stage length is extended. For dark oils the brightness level is less than the transparent type of oil. However, the stability of the cooling performance is high because the vapor blanket stage length is hardly changed.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

scholarly journals Analytical Modeling and Design of Novel Conical Halbach Permanent Magnet Couplings for Underwater Propulsion

2021 ◽  
Vol 9 (3) ◽  
pp. 290
Author(s):  
Yukai Li ◽  
Yuli Hu ◽  
Youguang Guo ◽  
Baowei Song ◽  
Zhaoyong Mao
Keyword(s):  
Permanent Magnet ◽  
Analytical Calculation ◽  
Underwater Propulsion ◽  
Conical Structure ◽  
Torque Analysis ◽  
Dynamic Seal ◽  
And Performance ◽  
The Stability ◽  
Propulsion Unit ◽  
Force Calculation

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.

Adaptive attitude-tracking control of spacecraft considering on-orbit refuelling

2020 ◽  
pp. 014233122097313
Author(s):  
Yiqi Xu
Keyword(s):  
Tracking Control ◽  
Closed Loop ◽  
Closed Loop System ◽  
Tracking Errors ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Inertia Model ◽  
And Performance ◽  
Attitude Tracking Control ◽  
The Stability

This paper studies the attitude-tracking control problem of spacecraft considering on-orbit refuelling. A time-varying inertia model is developed for spacecraft on-orbit refuelling, which actually includes two processes: fuel in the transfer pipe and fuel in the tank. Based upon the inertia model, an adaptive attitude-tracking controller is derived to guarantee the stability of the resulted closed-loop system, as well as asymptotic convergence of the attitude-tracking errors, despite performing refuelling operations. Finally, numerical simulations illustrate the effectiveness and performance of the proposed control scheme.

Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

2011 ◽  
Vol 368-373 ◽  
pp. 2411-2416
Author(s):  
Jian Ping Han ◽  
Hai Peng Liu
Keyword(s):  
Ground Penetrating Radar ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Potential Threat ◽  
Real Performance ◽  
Design Requirements ◽  
And Performance ◽  
The Stability ◽  
Ground Penetrating ◽  
Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

Research and Development of Distributed Multistage TMD for Long Period Structure Using Coil Spring

2013 ◽  
Author(s):  
Osamu Furuya ◽  
Hiroshi Kurabayashi
Keyword(s):  
Low Cost ◽  
Tuned Mass Damper ◽  
Installation Space ◽  
Coil Spring ◽  
Additional Mass ◽  
Natural Period ◽  
Long Period ◽  
Compact Size ◽  
Mass Damper ◽  
And Performance

The response control techniques are mainly divided into two categories. One is a storey installation damper type using a damping element such as oil, elasto-plastic, viscoelastic, and so on. The other is an additional mass damper type such as a active and passive type tuned mass damper including a hybrid type. The device configuration of later damper type becomes larger into high-rise structure and long natural period structure because of increase of additional mass in the same case of mass ratio and necessary design stroke of moving mass. In generally, however, it is desired to be a compact size with a same vibration attenuation performance because of that there is a limitation of installation space for the device, and also it is important to be realize the application of the damper with low cost and with a necessary specification for damper performance. This study has been conducted to develop the passive tuned mass damper system using coil spring for long period structure considering a design indexes such as compact size, low cost and robustness. Although a coil spring has been well used by the tuned mass damper system as one way of solving a cost problem and performance stability, the problem of compact size still remains in case of the application to a long period structure. Multistage type is therefore proposed to the system in this time. Furthermore, the distributed TMD theory is applied to the system for robustness of the system. This paper summarizes from a basic theory to the application of proposed device to the real scale long period structure.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

scholarly journals MICROMORPHOLOGICAL DIAGNOSIS OF THE STABILITY OF CHERNOZEMS UNDER IRRIGATION

2014 ◽  
pp. 52-73 ◽  
Author(s):  
T. V. Tursina
Keyword(s):  
Irrigation Water ◽  
Ionic Composition ◽  
Soil Porosity ◽  
Long Period ◽  
The Stability ◽  
Anthropogenic Evolution

Chernozems under irrigation for a long period of time have been studied using the micromorphological methods. The soil porosity, the amount of microaggregates, biogeneity, humus microforms and the presence or formation of optically oriented clay were taken as the basic indices for estimating the stability of chernozems to irrigation during 30-50 years. The different ionic composition of the irrigation water serves as evidence of varying anthropogenic evolution of chernozems.

Sign in / Sign up

Export Citation Format

Share Document