scholarly journals Tribology in Space Robotic Actuators: Experimental Method for Evaluation and Analysis of Gearboxes

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 75
Author(s):  
Erik Nyberg ◽  
Dídac Llopart i Cervelló ◽  
Ichiro Minami
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Space Applications ◽  
Effective Boundary ◽  
N2 Atmosphere ◽  
Advanced Analysis ◽  
And Performance ◽  
Microscopy Techniques ◽  
Film Separation

Liquid lubricants are critical to enable long-life operation of high-performance machinery, such as geared actuators employed in robotics. In space applications, actuator gearboxes must operate in low temperatures, where liquid lubricants face inherent problems related to low temperature rheology. Heaters are relied upon to provide acceptable gearbox temperatures. Unfortunately, heating is energy-intense and does not scale well with increasing mechanism mass and performance. Effective boundary lubrication (BL), on the other hand, can minimize problems of low temperature rheology. BL relies on tribofilm formation over conventional fluid film separation. Effective space grade boundary lubricants can potentially allow for drastically reduced amounts of oil and the accompanying rheological problems. In this work, we describe the design of a methodology to evaluate and analyze tribology of actuator gearboxes operated under cryogenic oil-starved conditions in N2 atmosphere. The devised methodology enables research pertinent to space actuator tribology by accelerated testing and advanced analysis, as demonstrated by a lubricant candidate case study. Complementary microscopy techniques are discussed, and a novel methodology devised for gear internal microstructure analysis by X-ray microtomography (XMT) is presented.

scholarly journals Design of Visual Display Terminal Paramaters for Visual Comfort and Performance

2013 ◽  
Vol 10 ◽  
pp. 184-189
Author(s):  
Hartomo ◽  
Abdul Djalal ◽  
Kokoh Kurniawan ◽  
Rachmah Nanda Kartika
Keyword(s):  
High Performance ◽  
Visual Display ◽  
Position Angle ◽  
University Student ◽  
Eye Position ◽  
Optimum Level ◽  
Visual Comfort ◽  
Visual Display Terminal ◽  
And Performance

The purpose of this study is to design the Visual Display Terminal parameters for the visual comfort and high performance. Taguchis Design of Experiments method was used to determine the optimum level of parameters that consist of external and internal lighthing, monitor position angle and eye-to-monitor distance. An experimental study was conducted in Ergonomics laboratory. Typing operation was done as a case study. 15 university student (7 males and 8 females) with age rangebetween 21-26 old took participation.The results of study findsthat the optimum external lighting (A1) = 1325 Lux, the monitor eye position angle (B2) = 15 o, The distance vision from eye - monitor (C1) = 20 inches, internal lighting (D1) = 60 Lux. This study has also found that eyesblinking decrease about 50% and the performance increase about 89.76%.Thus, the parameters of VDT can produce better visual comfort and performance.

scholarly journals Design, Construction and Validation of a High-Performance OATS

2021 ◽  
Author(s):  
Donglin Meng
Keyword(s):  
High Performance ◽  
Ground Plane ◽  
Test Site ◽  
The World ◽  
And Performance ◽  
Antenna Factor ◽  
First Time ◽  
Biconical Antennas ◽  
Calibration Laboratories

The state of the art on the open-area test site (OATS) has been introduced. Key technologies on the design and validation of a high-performance OATS have been provided. Some famous OATS in the world regarding their structure, the dimensions of the ground plane (GP), the location of the control room, and performance are listed in a table. A case study is provided on NIM’s high-performance OATS. Many details are open for the first time, which show the fine design. A measurement uncertainty example has been provided in measuring the free-space antenna factor of biconical antennas. These results are based on the author’s many years of experience, with lots of valuable data and photos. It is intended for calibration laboratories, for EMC antenna users, for writing EMC standards, as well as for the assessors in EMC.

scholarly journals Preparation and Performance Evaluation of Reforming Prehydrogenation Catalyst Used for Blending Inferior Coking Gasoline

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Tiezhen Zhang ◽  
◽  
Yungang Jia ◽  
Famin Sun ◽  
Liang Wang ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Low Temperature ◽  
High Performance ◽  
Active Component ◽  
Raw Materials ◽  
Volume Ratio ◽  
Good Activity ◽  
Reaction Pressure ◽  
Excellent Activity ◽  
And Performance

A reforming prehydrogenation catalyst suitable for blending inferior coking gasoline was developed by the supporter modification, selection and optimization of active component. The catalyst has high performance of hydrodesulfurization, hydrodenitrification and olefin saturation at low temperature. The catalyst has good activity and strong adaptability to raw materials, At reaction pressure of 2.0MPa, hydrogen-oil volume ratio of 200:1, LHSV of 5.0h-1, reaction temperature of 268-280℃, it can process the prehydrogenation raw materials blending inferior hydrocoking gasoline (20-50%), and the generated oil can meet the requirements of reforming feed. The results of 1500h activity stability test show that the catalyst has excellent activity stability.

scholarly journals Review of State-of-the-Art Green Monopropellants: For Propulsion Systems Analysts and Designers

Aerospace ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 20
Author(s):  
Ahmed E. S. Nosseir ◽  
Angelo Cervone ◽  
Angelo Pasini
Keyword(s):  
Environmental Sustainability ◽  
Electric Propulsion ◽  
High Performance ◽  
Systems Design ◽  
Propulsion Systems ◽  
Space Applications ◽  
Analysis And Design ◽  
Research Activities ◽  
Systems Analysts ◽  
And Performance

Current research trends have advanced the use of “green propellants” on a wide scale for spacecraft in various space missions; mainly for environmental sustainability and safety concerns. Small satellites, particularly micro and nanosatellites, evolved from passive planetary-orbiting to being able to perform active orbital operations that may require high-thrust impulsive capabilities. Thus, onboard primary and auxiliary propulsion systems capable of performing such orbital operations are required. Novelty in primary propulsion systems design calls for specific attention to miniaturization, which can be achieved, along the above-mentioned orbital transfer capabilities, by utilizing green monopropellants due to their relative high performance together with simplicity, and better storability when compared to gaseous and bi-propellants, especially for miniaturized systems. Owing to the ongoing rapid research activities in the green-propulsion field, it was necessary to extensively study and collect various data of green monopropellants properties and performance that would further assist analysts and designers in the research and development of liquid propulsion systems. This review traces the history and origins of green monopropellants and after intensive study of physicochemical properties of such propellants it was possible to classify green monopropellants to three main classes: Energetic Ionic Liquids (EILs), Liquid NOx Monopropellants, and Hydrogen Peroxide Aqueous Solutions (HPAS). Further, the tabulated data and performance comparisons will provide substantial assistance in using analysis tools—such as: Rocket Propulsion Analysis (RPA) and NASA CEA—for engineers and scientists dealing with chemical propulsion systems analysis and design. Some applications of green monopropellants were discussed through different propulsion systems configurations such as: multi-mode, dual mode, and combined chemical–electric propulsion. Although the in-space demonstrated EILs (i.e., AF-M315E and LMP-103S) are widely proposed and utilized in many space applications, the investigation transpired that NOx fuel blends possess the highest performance, while HPAS yield the lowest performance even compared to hydrazine.

An In-Situ Post Growth Annealing Process for the Improvement of 4H-SiC/SiO2 MOS Interface Prepared by CVD Using TEOS, and its Characteristic Study

2005 ◽  
Vol 483-485 ◽  
pp. 681-684
Author(s):  
Kumaresan Ramanujam ◽  
Hidetsugu Furuichi ◽  
Koshi Taguchi ◽  
Satoshi Yukumoto ◽  
Shigehiro Nishino
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Semiconductor Device ◽  
Oxide Semiconductor ◽  
Interface Properties ◽  
Amorphous Sio2 ◽  
Interface Quality ◽  
N2 Atmosphere ◽  
The One

Investigations were carried out to achieve high performance Silicon Carbide Metal-Oxide-Semiconductor device structures. 4H-SiC/SiO2 interface was prepared by growing amorphous SiO2 layers by an alternate low temperature atmospheric CVD technique using TEOS as source material and the interface properties were compared with the one prepared by conventional thermal oxidation technique. The low temperature CVD technique offered the improvement of the interface properties with reduced Dit in comparison with thermally oxidized interface. As a new attempt, an in situ post growth annealing technique in N2 atmosphere was carried out to reduce the Dit further. Both the CVD technique and the in situ annealing processes that were used in the present study have been identified to be potential approaches to improve the interface quality.

Trace nanoanalysis

1994 ◽  
Vol 52 ◽  
pp. 940-941
Author(s):  
D. E. Newbury ◽  
R. D. Leapman
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Detection Efficiency ◽  
Volume Element ◽  
And Performance ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Concentration Levels ◽  
Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

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