Effect of the Altitudes and Eccentricity of the Initial Orbit on Satellite Transition Efficiency

This research dealt with choosing the best satellite parking orbit and then the transition of the satellite from the low Earth orbit to the geosynchronous orbit (GEO). The aim of this research is to achieve this transition with the highest possible efficiency (lowest possible energy, time, and fuel consumption with highest accuracy) in the case of two different inclination orbits. This requires choosing a suitable primary parking orbit. All of the methods discussed in previous studies are based on two orbits at the same plane, mostly applying the circular orbit as an initial orbit. This transition required the use of the advanced technique of the Hohmann transfer method for the elliptical orbits, as we did in an earlier research, namely the transition from the perigee of the initial orbit to the final orbit and then conducting the rotation of the orbit plane to match the plane for the desired final orbit. The effect of the perigee altitude of the initial orbit on the transition efficiency calculated for the values between 300 to 3000 km. It was found that increasing the altitude reduces the energy and fuel needed for transportation, but the time required for transportation increases, into account that the increased height of the initial or parking orbit also implies the requirement of higher energy to reach it. The effects of eccentricity (e) values of the initial orbit between 0.01 to 0.2 on the transition efficiency were calculated. It was found that the increase in (e) reduces the energy and fuel, but does not affect the time, required for transportation.

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Determination and evaluation of the orbital transition methods between two elliptical earth orbits

Iraqi Journal of Science ◽

10.24996/ijs.2020.61.1.25 ◽

2020 ◽

pp. 224-234

Author(s):

Farid M. Mahdi ◽

Abdul-Rahman H. Salih ◽

Majeed M. Jarad

Keyword(s):

Initial Conditions ◽

Multi Stage ◽

Parking Orbit ◽

Energy Consuming ◽

Stage Transition ◽

The Many ◽

Earth Orbits ◽

Orbital Transition ◽

Minimal Consumption ◽

Initial Orbit

To transfer a satellite or a spacecraft from a low parking orbit to a geosynchronous orbit, one of the many transition methods is used. All these methods need to identify some orbital elements of the initial and final orbits as perigee and apogee distances. These methods compete to achieve the transition with minimal consumption of energy, transfer time and mass ratio consumed ), as well as highest accuracy of transition. The ten methods of transition used in this project required designing programs to perform the calculations and comparisons among them. The results showed that the evaluation must depend on the initial conditions of the initial orbit and the satellite mechanical exception as well as the target orbit. The most efficient methods of transition in terms of energy required were, sequentially, methods 10, 1, 8, 9, and 2, whereas the least efficient in terms of energy consumption, fuel and transition time were, sequentially, methods 5,6, and 7. Method 3 was the most efficient when the orbit needed to change the inclination with the transition. The first phase of multi-stage transition is the most energy consuming.

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Astrodynamical middle-frequency interferometric gravitational wave observatory AMIGO: Mission concept and orbit design

International Journal of Modern Physics D ◽

10.1142/s0218271819400078 ◽

2020 ◽

Vol 29 (04) ◽

pp. 1940007 ◽

Cited By ~ 2

Author(s):

Wei-Tou Ni ◽

Gang Wang ◽

An-Ming Wu

Keyword(s):

Black Hole ◽

Neutron Star ◽

Gravitational Wave ◽

First Generation ◽

Noise Suppression ◽

Laser Frequency ◽

Low Earth Orbit ◽

Frequency Noise ◽

Orbit Plane ◽

Solar Orbit

AMIGO is a first-generation Astrodynamical Middle-frequency Interferometric Gravitational Wave (GW) Observatory. The scientific goals of AMIGO are to bridge the spectra gap between first-generation high-frequency and low-frequency GW sensitivities: to detect intermediate mass BH coalescence; to detect inspiral phase and predict time of binary black hole coalescences together with binary neutron star & black hole-neutron star coalescences for ground interferometers; to detect compact binary inspirals for studying stellar evolution and galactic population. The mission concept is to use time delay interferometry (TDI) for a nearly triangular formation of three drag-free spacecraft with nominal arm length 10,000 km, emitting laser power 2–10 W and telescope diameter 300–500 mm. The design GW sensitivity in the middle frequency band is [Formula: see text] Hz[Formula: see text]. Both geocentric and heliocentric orbit formations are considered. All options have LISA-like formations, that is, the triangular formation is [Formula: see text] inclined to the orbit plane. For all solar orbit options of AMIGO, the first-generation TDI satisfies the laser frequency-noise suppression requirement. We also investigate for each option of orbits under study, whether constant equal-arm implementation is feasible. For the solar-orbit options, the acceleration to maintain the formation can be designed to be less than 15 nm/s2 with the thruster requirement in the 15 [Formula: see text]N range. AMIGO would be a good place to test the feasibility of the constant equal-arm option. Fuel requirement, thruster noise requirement and test mass acceleration actuation requirement are briefly considered. From the orbit study, the solar orbit option is the mission orbit preference. We study the deployment for this orbit option. After a last-stage launch from 300 km Low Earth Orbit (LEO), each S/C’s maneuver to an appropriate 2-degree-behind-the-Earth AMIGO formation in 95 days requires only a [Formula: see text]v of about 80 m/s.

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Evaluation of Quick Bacterial Count Methods for Assessment of Food Plant Sanitation

Journal of Food Protection ◽

10.4315/0362-028x-41.4.269 ◽

1978 ◽

Vol 41 (4) ◽

pp. 269-271 ◽

Cited By ~ 10

Author(s):

C. G. STINSON ◽

N. P. TIWARI

Keyword(s):

Microbial Contamination ◽

Direct Method ◽

Bacterial Count ◽

Food Plant ◽

Plant Equipment ◽

Transfer Method ◽

Time Required ◽

Chemical Corporation ◽

A Direct Method ◽

Good Agreement

Four methods to detect microbial contamination on food plant equipment surfaces were compared to determine the accuracy, precision, cost and time required to do each test. A standard method for swabbing; a simplified swab test (Millipore Corporation); a contact-transfer method (Con-Tact-It, Birko Chemical Corporation) and a direct method using Rodac plates (BBL) were evaluated. The equipment surfaces were found to be highly contaminated indicating the necessity for regular microbial testing. Under conditions of the test, there was good agreement in enumeration of bacteria between the standard swab test and both the Millipore swab method and the Con-Tact-It system; the standard swab method and Rodac plates showed the best precision. The contact methods were by far the quickest tests to do, and the Con-Tact-It system was the least expensive.

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Radiation Hazards in Low Earth Orbit, Polar Orbit, Geosynchronous Orbit, and Deep Space

Terrestrial Space Radiation and Its Biological Effects ◽

10.1007/978-1-4613-1567-4_6 ◽

1988 ◽

pp. 71-96 ◽

Cited By ~ 3

Author(s):

Percival D. McCormack

Keyword(s):

Low Earth Orbit ◽

Geosynchronous Orbit ◽

Earth Orbit ◽

Deep Space ◽

Radiation Hazards ◽

Polar Orbit

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The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068382 ◽

1970 ◽

Vol 28 ◽

pp. 278-279

Author(s):

Charles TurnbiLL ◽

Delbert E. Philpott

Keyword(s):

Electron Microscopy ◽

Carbon Dioxide ◽

Surface Tension ◽

Critical Point ◽

Freeze Drying ◽

Attractive Alternative ◽

Crystal Formation ◽

Critical Point Drying ◽

Time Required ◽

Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

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Search mode for rapid detection of virus particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100085733 ◽

1991 ◽

Vol 49 ◽

pp. 286-287

Author(s):

O. E. Bradfute

Keyword(s):

Electron Microscopy ◽

Rapid Detection ◽

Plant Virus ◽

Low Dose ◽

Search Mode ◽

Virus Diseases ◽

Virus Particles ◽

Focus Image ◽

Time Required ◽

Rapid Switching

Electron microscopy is frequently used in preliminary diagnosis of plant virus diseases by surveying negatively stained preparations of crude extracts of leaf samples. A major limitation of this method is the time required to survey grids when the concentration of virus particles (VPs) is low. A rapid survey of grids for VPs is reported here; the method employs a low magnification, out-of-focus Search Mode similar to that used for low dose electron microscopy of radiation sensitive specimens. A higher magnification, in-focus Confirm Mode is used to photograph or confirm the detection of VPs. Setting up the Search Mode by obtaining an out-of-focus image of the specimen in diffraction (K. H. Downing and W. Chiu, private communications) and pre-aligning the image in Search Mode with the image in Confirm Mode facilitates rapid switching between Modes.

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Microwaves: Application in Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158248 ◽

1990 ◽

Vol 48 (3) ◽

pp. 140-141

Author(s):

Anthony S-Y Leong ◽

David W Gove

Keyword(s):

Electron Microscopy ◽

Light Microscopy ◽

Chemical Reactions ◽

Electromagnetic Waves ◽

Tissue Fixation ◽

Primary Method ◽

Dipolar Molecules ◽

Wide Range ◽

Time Required ◽

Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

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Clinical Update: Functional Capacity Evaluations—An Update

Guides Newsletter ◽

10.1001/amaguidesnewsletters.1999.sepoct02 ◽

1999 ◽

Vol 4 (5) ◽

pp. 4-7 ◽

Cited By ~ 1

Author(s):

Laura Welch

Keyword(s):

Job Performance ◽

Functional Capacity ◽

Injury Risk ◽

Disability Evaluation ◽

Time Period ◽

Submaximal Effort ◽

Lack Of Sleep ◽

Overall Performance ◽

Time Required ◽

Specific Limitation

Abstract Functional capacity evaluations (FCEs) have become an important component of disability evaluation during the past 10 years to assess an individual's ability to perform the essential or specific functions of a job, both preplacement and during rehabilitation. Evaluating both job performance and physical ability is a complex assessment, and some practitioners are not yet certain that an FCE can achieve these goals. An FCE is useful only if it predicts job performance, and factors that should be assessed include overall performance; consistency of performance across similar areas of the FCE; consistency between observed behaviors during the FCE and limitations or abilities reported by the worker; objective changes (eg, blood pressure and pulse) that are appropriate relative to performance; external factors (illness, lack of sleep, or medication); and a coefficient of variation that can be measured and assessed. FCEs can identify specific movement patterns or weaknesses; measure improvement during rehabilitation; identify a specific limitation that is amenable to accommodation; and identify a worker who appears to be providing a submaximal effort. FCEs are less reliable at predicting injury risk; they cannot tell us much about endurance over a time period longer than the time required for the FCE; and the FCE may measure simple muscular functions when the job requires more complex ones.

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