• Title/Summary/Keyword: gravity recovery

Search Result 116, Processing Time 0.032 seconds

Data Reductions of Gravity Recovery and Climate Experiment (GRACE) Gravity Solutions and Their Applications (Gravity Recovery and Climate Experiment (GRACE) 중력자료 해석을 위한 자료 처리 및 응용)

  • Seo, Ki-Weon
    • Journal of the Korean earth science society
    • /
    • v.32 no.6
    • /
    • pp.586-594
    • /
    • 2011
  • Gravity Recovery and Climate Experiment (GRACE), launched in April, 2002, makes it possible to monitor Earth's mass redistribution with its time-varying gravity observation. GRACE provides monthly gravity solutions as coefficients of spherical harmonics, and thus ones need to convert the gravity spectrum to gravity grids (or mass grids) via the spherical harmonics. GRACE gravity solutions, however, include spatial alias error as well as noise, which requires to suppress in order to enhance signal to noise ratio. In this study, we present the GRACE data processing procedures and introduce some applications of time-varying gravity, which are studies of terrestrial water storage changes, Antarctic and Greenland ice melting, and sea level rise. Satellite missions such as GRACE will continue up to early 2020, and they are expected to be an essential resource to understand the global climate changes.

Alternate Energy: Gravity Powered Rail Transportation Systems

  • Bojji, Rajaram
    • International Journal of Railway
    • /
    • v.2 no.1
    • /
    • pp.22-29
    • /
    • 2009
  • A simple pendulum shows how efficient gravity is in recovering energy. Any transportation is a linearly oscillating system; every load gains kinetic energy, but loses the same to come to a stop. The Gravity Power Towers comprise of a set of vertically moving heavy masses coupled, through microprocessor controlled continuously variable gear and cable system, to a horizontally rolling unit on wheels either on rail or road. The heavy masses move vertically up against gravity gaining potential energy while stopping a moving mass; move down under gravity force, giving out energy. The Tower thus accelerates or sustains the speed a rolling unit, and while decelerating, recover the kinetic energy. Speeds of 360 kmph can be attained. Recovery of energy varies from 98.5-70%; the longer the distance between stops, the lesser is recovery. The economical, omnipresent & eternal Gravity Power grants energy independence to many a nation. Global warming reduces.

  • PDF

Development of Gravity-induced Loss of Consciousness(GLOC) Monitoring System and Automatic Recovery System (중력 가속도로 인한 의식상실 감지 및 자동 회복 시스템 개발)

  • Kim, Chong-Sup;Hwang, Byung-Moon;Kang, Im-Ju;Jang, Soon-Ryong;Kim, Kwang-Yun;Park, Myung-Hwan
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.17 no.7
    • /
    • pp.704-713
    • /
    • 2011
  • For many years, many pilots lost their lives and aircrafts due to GLOC(Gravity-induced Loss Of Consciousness). Due to the emergence of high-gravity maneuvering aircraft such as the F-16, F-15 and T-50, the automatic GLOC detection and recovery systems are necessary to increase the aircraft safeties even when the pilot loses his consciousness due to high-G maneuvering. This paper addresses the design of GLOC detection, warning and recovery algorithm based on a model of supersonic jet trainer. The system is solely controlled by the pilot's control input (i.e., control stick force) and aircraft status such as attitude, airspeed, altitude and so forth. And, moreover, it does not depend upon any pilot physiological condition. The test evaluation results show that the developed system supports the recovery of an aircraft from the unusual aircraft attitude and improves the aircraft safeties even when the pilot loses his consciousness due to high-G maneuvering.

Improvement of Earth Gravity Field Maps after Pre-processing Upgrade of the GRACE Satellite's Star Trackers

  • Ko, Ung-Dai;Wang, Furun;Eanes, Richard J.
    • Korean Journal of Remote Sensing
    • /
    • v.31 no.4
    • /
    • pp.353-360
    • /
    • 2015
  • Earth's gravity field recovery was improved after the pre-processing upgrade of the Gravity Recovery And Climate Experiments (GRACE) satellite's star trackers. The star tracker measurements were filtered with a tighter low-pass filtering of 0.025Hz cutoff frequency, instead of a nominal filtering of 0.1Hz cutoff frequency. In addition, a jump removal algorithm was applied to remove discontinuities, due to direct Sun and/or Moon interventions, in the star tracker measurements. During the K-Band Ranging (KBR) calibration maneuvers, large attitude variations could be detected concurrently by both of the star trackers and the accelerometer. The misalignment angles of star trackers between the true frame and the normal frame could be determined by comparing measurements from these sensors. In this paper, new Earth' gravity field maps were obtained using above improvement. Based on comparisons to nominal Earth's gravity field maps, the new Earth's gravity field maps were found better than the nominal ones. Among the applied methods, the misalignment calibration of the star trackers had a major impact on the improvement of the new Earth's gravity field maps.

Spaceborne Gravity Sensors for Continental Hydrology and Geodynamic Studies

  • Shum C. K.;Han Shin-Chan;Braun Alexander
    • Korean Journal of Remote Sensing
    • /
    • v.21 no.1
    • /
    • pp.51-57
    • /
    • 2005
  • The currently operating NASA/GFZ Gravity Recovery and Climate Experiment (GRACE) mission is designed to measure small mass changes over a large spatial scale, including the mapping of continental water storage changes and other geophysical signals in the form of monthly temporal gravity field. The European Space Agency's Gravity field and steady state Ocean Circulation Explorer (GOCE) space gravity gradiometer (SGG) mission is anticipated to determine the mean Earth gravity field with an unprecedented geoid accuracy of several cm (rms) with wavelength of 130km or longer. In this paper, we present a summary of present GRACE studies for the recovery of hydrological signals in the Amazon basin using alternative processing and filtering techniques, and local inversion to enhance the temporal and spatial resolutions by two-folds or better. Simulation studies for the potential GRACE detection of slow deformations due to Nazca-South America plate convergence and glacial isostatic adjustment (GIA) signals show that these signals are at present difficult to detect without long-term data averaging and further improvement of GRACE measurement accuracy.

Transcervical Embryo Recovery in Korean Black Goats: A Preliminary Experiment

  • Lee, Doo-Soo;Kim, Dong-Woo;Shin, Sang Tae
    • Journal of Embryo Transfer
    • /
    • v.30 no.3
    • /
    • pp.171-174
    • /
    • 2015
  • Four pluriparous Korean black goat does were superovulated with FSH and mated with fertile bucks. Anesthetized animals were placed in lateral recumbency, then size 8 Foley catheter was inserted into the uterus through the cervix under the vaginal speculum and the balloon was inflated to fix the catheter in the uterine body. The opposite end of the catheter was connected to a 3-way and a flushing medium was infused into the uterus. Modified Dubecco's PBS with 1% FBS was used as the flushing medium. Four goats were allocated in two groups depending on the type of medium infusion into uterus. Injection group; the flushing medium was injected into uterus and the infused medium was collected by to-and-fro method using a syringe. Gravity-flow group; the flushing medium was allowed to enter the uterus by gravity flow by lifting the medium bottle and drained out of the uterus into a collecting tube. All four goats had catheter inserted through the cervix and uteri flushed successfully. The volume (recovery rate) of recovered medium varied considerably from 87 ml/200 ml (43.5%) to 148 ml/160 ml (92.5%). Nine embryos/ova in total were recovered from Gravity-flow group goats. Although the embryo recovery rate was low, the possibility of a transcervical embryo recovery in Korean black goat had been proven in this preliminary experiment.

Gravity Estimation by Using Low-Low Inter-Satellite Tracking Data (저궤도 위성간 추적데이터를 이용한 지구중력장 측정)

  • Kim,Jeong-Rae
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.31 no.8
    • /
    • pp.58-68
    • /
    • 2003
  • Accurate estimation of the Earth gravity field plays an important role in understanding the Earth geodynamic activities. After brief discussion on the objective of the gravity estimation, dedicated satellite missions for this purpose are described. Recently launched NASA/DLR Gravity Recovery and Climate Experiment (GRACE) mission, which consists of two co-orbiting low altitude satellites, is described. For the performance analysis, full numerical simulation was performed. The simulation procedure and its key instrument modelings are described. From the simulation results, a significant improvement on the Earth gravity field accuracy is expected.

Recovery of Petroleum Hydrocarbons from Oily Sludge Landfilled Soil

  • Shin, Su-Yeon;Park, Sang-Min;Ko, Sung-Hwan;Jung, Hong-Bae;Baek, Kitae
    • Journal of Soil and Groundwater Environment
    • /
    • v.20 no.5
    • /
    • pp.41-46
    • /
    • 2015
  • Three types of experiments, based on the physical properties of oily sludge landfilled soil, were conducted to recover total petroleum hydrocarbons (TPH) from the soil. These experiments included gravity separation, solvent extraction using water, and air floatation. The oil portion was not easily separated from the wet (raw) soil because water molecules aggregate the soil particles, despite the fact that the soil was sandy. However, the drying and grinding processes destroyed the aggregates, causing the TPH recovery to increase to approximately 60% when air floatation was used. The drying process decreased the specific gravity of the soil sample, thereby enhancing the overall recovery of TPH from the soil. Although thermal desorption and/or incineration are common choices for heavily dumped sites, physical separation can recover the oil portion instead of simply removing it.

Simulation Modeling of Range and Acceleration Measurement Instruments for Satellite Formation Flying (편대비행 위성용 거리 및 가속도 관측기 시뮬레이션 모델링)

  • Kim, Jeong-Rae
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.33 no.2
    • /
    • pp.75-83
    • /
    • 2005
  • NASA/DLR Gravity Recovery and Climate Experiment (GRACE) mission, which consists of two co-orbiting low altitude satellites, is to measure the Earth gravity field with unprecedented accuracy. Its key instruments include inter-satellite ranging systems and three-axis accelerometers. For the preliminary design and requirements analysis, extensive instrument simulation models are developed. These modeling techniques and orbit-gravity field estimation techniques are described.

Diagnostic metallurgy of porphyry copper-gold deposits in the Pan-Pacific

  • Kim Joe Y.;Kim Sun S.;Shin Hyung J.;Kong Bong S.;Lee Keon K.
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2003.11a
    • /
    • pp.581-589
    • /
    • 2003
  • The variable flotation response ores from different deposits results basically from mineralogical association and their differences. Development of new techniques for analyzing the metallurgical performance of flotation and other concentration processes is demanded even in the treatment of rather simple ores such as porphyry ores. Diagnostic metallurgical analysis can be used to quantify the most possible recovery processes. Several porphyry copper/gold ores around the world were used to examine the responses in flotation, gravity separation and cyanidation in order to define the linkage between the recovery processes for both copper and old values. Laboratory batch flotation, gravity separation and cyanidation tests were carried out on these samples. All results were used to correlate the relative recovery of copper and gold, and to predict the highest possible metal recovery in the system. The metallurgical predictions were made according to the flotation conditions used and gravity separation. The results of various concentration processes on each porphyry ore samples are presented and discussed. All seven samples have shown significantly different gold/copper metallurgy. The grade/recovery relationships of gold and copper in the laboratory batch tests for the best results and the plants are given in the Figures below. The results of laboratory tests show that the copper recoveries converged to about $90\%$, but the gold recoveries were spread over $55-80\%$, except the K S ore. Series of standard cyanidation tests on the flotation concentrate samples and gravity separation using Knelson Separator on heads ores were carried out to cross-link the metallurgy and mineralogy of gold in the porphyry ores.

  • PDF