10 research outputs found
Adhesion of Lunar Dust
This paper reviews the physical characteristics of lunar dust and the effects of various fundamental forces acting on dust particles on surfaces in a lunar environment. There are transport forces and adhesion forces after contact. Mechanical forces (i.e., from rover wheels, astronaut boots and rocket engine blast) and static electric effects (from UV photo-ionization and/or tribo-electric charging) are likely to be the major contributors to the transport of dust particles. If fine regolith particles are deposited on a surface, then surface energy-related (e.g., van der Walls) adhesion forces and static-electric-image forces are likely to be the strongest contributors to adhesion. Some measurement techniques are offered to quantify the strength of adhesion forces. And finally some dust removal techniques are discussed
CFD Modeling of Complex Chemical Processes: Multiscale and Multiphysics Challenges
Computational fluid dynamics (CFD), which uses numerical analysis to predict and model complex flow behaviors and transport processes, has become a mainstream tool in engineering process research and development. Complex chemical processes often involve coupling between dynamics at vastly different length and time scales, as well as coupling of different physical models. The multiscale and multiphysics nature of those problems calls for delicate modeling approaches. This book showcases recent contributions in this field, from the development of modeling methodology to its application in supporting the design, development, and optimization of engineering processes
Research and Technology 1995
This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for fiscal year 1995. It comprises over 150 short articles submitted by the staff members of the technical directorates. The report is organized into six major sections: aeronautics, aerospace technology, space flight systems, engineering support, Lewis Research Academy, and technology transfer. A table of contents, an author index, and a list of NASA Headquarters program offices have been included to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff members and contractors (for abstracts of these Lewis-authored reports, visit the Lewis Technical Report Server (LETRS) on the World Wide Web-http://letrs.lerc.nasa.gov/LeTRS/). In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. For more information about Lewis' research, visit us on the World Wide web-http://www.lerc.nasa.gov
NASA thesaurus. Volume 2: Access vocabulary
The access vocabulary, which is essentially a permuted index, provides access to any word or number in authorized postable and nonpostable terms. Additional entries include postable and nonpostable terms, other word entries and pseudo-multiword terms that are permutations of words that contain words within words. The access vocabulary contains almost 42,000 entries that give increased access to the hierarchies in Volume 1 - Hierarchical Listing
NASA thesaurus. Volume 2: Access vocabulary
The Access Vocabulary, which is essentially a permuted index, provides access to any word or number in authorized postable and nonpostable terms. Additional entries include postable and nonpostable terms, other word entries, and pseudo-multiword terms that are permutations of words that contain words within words. The Access Vocabulary contains 40,738 entries that give increased access to the hierarchies in Volume 1 - Hierarchical Listing
Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress
Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018
Social work with airports passengers
Social work at the airport is in to offer to passengers social services. The main
methodological position is that people are under stress, which characterized by a
particular set of characteristics in appearance and behavior. In such circumstances
passenger attracts in his actions some attention. Only person whom he trusts can help him
with the documents or psychologically
Time Localization of Abrupt Changes in Cutting Process using Hilbert Huang Transform
Cutting process is extremely dynamical process influenced by different phenomena such as chip formation, dynamical responses and condition of machining system elements. Different phenomena in cutting zone have signatures in different frequency bands in signal acquired during process monitoring. The time localization of signalβs frequency content is very important.
An emerging technique for simultaneous analysis of the signal in time and frequency domain that can be used for time localization of frequency is Hilbert Huang Transform (HHT). It is based on empirical mode decomposition (EMD) of the signal into intrinsic mode functions (IMFs) as simple oscillatory modes. IMFs obtained using EMD can be processed using Hilbert Transform and instantaneous frequency of the signal can be computed.
This paper gives a methodology for time localization of cutting process stop during intermittent turning. Cutting process stop leads to abrupt changes in acquired signal correlated to certain frequency band. The frequency band related to abrupt changes is localized in time using HHT. The potentials and limitations of HHT application in machining process monitoring are shown
ΠΡΠΈΠΊΠ»Π°Π΄Π½Π° ΡΡΠ·ΠΈΠΊΠ° : ΡΠΊΡΠ°ΡΠ½ΡΡΠΊΠΎ-ΡΠΎΡΡΠΉΡΡΠΊΠΎ-Π°Π½Π³Π»ΡΠΉΡΡΠΊΠΈΠΉ ΡΠ»ΡΠΌΠ°ΡΠ½ΠΈΠΉ ΡΠ»ΠΎΠ²Π½ΠΈΠΊ. Π£ 4 Ρ. Π’. 1. Π β Π
Π‘Π»ΠΎΠ²Π½ΠΈΠΊ ΠΎΡ
ΠΎΠΏΠ»ΡΡ Π±Π»ΠΈΠ·ΡΠΊΠΎ 30 ΡΠΈΡ. ΡΠ΅ΡΠΌΡΠ½ΡΠ² Π· ΠΏΡΠΈΠΊΠ»Π°Π΄Π½ΠΎΡ ΡΡΠ·ΠΈΠΊΠΈ Ρ Π΄ΠΎΡΠΈΡΠ½ΠΈΡ
Π΄ΠΎ Π½Π΅Ρ Π³Π°Π»ΡΠ·Π΅ΠΉ Π·Π½Π°Π½Ρ ΡΠ° ΡΡ
ΡΠ»ΡΠΌΠ°ΡΠ΅Π½Π½Ρ ΡΡΡΠΎΠΌΠ° ΠΌΠΎΠ²Π°ΠΌΠΈ (ΡΠΊΡΠ°ΡΠ½ΡΡΠΊΠΎΡ, ΡΠΎΡΡΠΉΡΡΠΊΠΎΡ ΡΠ° Π°Π½Π³Π»ΡΠΉΡΡΠΊΠΎΡ). ΠΠ°Π³Π°ΡΠΎ ΡΠ΅ΡΠΌΡΠ½ΡΠ² Ρ Π²ΠΈΠ·Π½Π°ΡΠ΅Π½Ρ, Π½Π°Π²Π΅Π΄Π΅Π½ΠΈΡ
Ρ ΡΠ»ΠΎΠ²Π½ΠΈΠΊΡ, ΡΠΊΠΈΠΌΠΈ ΠΏΠΎΡΠ»ΡΠ³ΠΎΠ²ΡΡΡΡΡΡ Ρ Π²ΡΠ΄ΠΏΠΎΠ²ΡΠ΄Π½ΡΠΉ Π³Π°Π»ΡΠ·Ρ Π·Π½Π°Π½Ρ, Π΄ΠΎΡΡ Π½Π΅ Π²Ρ
ΠΎΠ΄ΠΈΠ»ΠΈ Π΄ΠΎ ΠΆΠΎΠ΄Π½ΠΎΠ³ΠΎ Π·Ρ
ΡΠΏΠ΅ΡΡΠ°Π»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ
ΡΠ»ΠΎΠ²Π½ΠΈΠΊΡΠ². Π‘Π»ΠΎΠ²Π½ΠΈΠΊ ΠΏΡΠΈΠ·Π½Π°ΡΠ΅Π½ΠΈΠΉ Π΄Π»Ρ Π²ΠΈΠΊΠ»Π°Π΄Π°ΡΡΠ², Π½Π°ΡΠΊΠΎΠ²ΡΡΠ², ΡΠ½ΠΆΠ΅Π½Π΅ΡΡΠ², Π°ΡΠΏΡΡΠ°Π½ΡΡΠ², ΡΡΡΠ΄Π΅Π½ΡΡΠ² Π²ΠΈΡΠΈΡ
Π½Π°Π²ΡΠ°Π»ΡΠ½ΠΈΡ
Π·Π°ΠΊΠ»Π°Π΄ΡΠ², ΠΏΠ΅ΡΠ΅ΠΊΠ»Π°Π΄Π°ΡΡΠ² Π· ΠΏΡΠΈΡΠΎΠ΄Π½ΠΈΡΠΈΡ
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