Efficiency of Superconducting Gravimeter Observations and Future Prospects

Neumeyer Juergen The Korean Society of Remote Sensing 2005 大韓遠隔探査學會誌 Vol.21 No.1

Superconducting Gravimeters (SG) are the most sensitive instruments for measuring temporal gravity variations. The gravimeter is an integrating sensor therefore the gravity variations caused by different sources must be separated for studying a special effect by applying different models and data analysis methods. The present reduction methods for gravity variations induced by atmosphere and hydrosphere including the ocean and the detection and determination of the most surface gravity effects are shown. Some examples demonstrate the combination of ground (SG) and space techniques especially the combination of SG with GRACE satellite derived temporal gravity variations. Resulting from the performance of the SG and the applied data analysis methods some proposals are made for future SG applications.

Efficiency of Superconducting Gravimeter Observations and Future Prospects

Juergen Neumeyer 大韓遠隔探査學會 2005 大韓遠隔探査學會誌 Vol.21 No.1

Superconducting Gravimeters (SG) are the most sensitive instruments for measuring temporal gravity variations. The gravimeter is an integrating sensor therefore the gravity variations caused by different sources must be separated for studying a special effect by applying different models and data analysis methods. The present reduction methods for gravity variations induced by atmosphere and hydrosphere including the ocean and the detection and determination of the most surface gravity effects are shown. Some examples demonstrate the combination of ground (SG) and space techniques especially the combination of SG with GRACE satellite derived temporal gravity variations. Resulting from the performance of the SC and the applied data analysis methods some proposals are made for future SG applications.

Gravimetric Monitoring of CO₂ Mass Balance in the Geological Reservoir

( Jeong Woo Kim ),( Juergen Neumeyer ),( Hojjat Kabirzadeh ) 대한지질공학회 2021 대한지질공학회 학술발표회논문집 Vol.2021 No.2

Simulation of Geological CO2 Storage with Micro Gravity

( Jeong Woo Kim ),( Juergen Neumeyer ),( Ricky Kao ),( Hojjat Kabirzadeh ) 대한지질공학회 2014 대한지질공학회 학술발표회논문집 Vol.2014 No.-

문경 초전도 중력계 설치 및 기초자료 분석

김태희,우익,박혁진,김정우,Kim, Tae-Hee,Neumeyer, Juergen,Woo, Ik,Park, Hyuck-Jin,Kim, Jeong-Woo 대한자원환경지질학회 2007 자원환경지질 Vol.40 No.4

Superconducting Gravimeter(SG) was installed and has been successfully operated at MunGyung, Kyungsang province in Korea in March 2005. It was registered as the 21st observatory of the Global Geodynamics Project. Since SG can precisely measure the gravity variations below the 1mHz frequency band, it has the outstanding capability to sense and resolve many different periodic gravity components from each other. From the raw data collected between 18 March 2005 and 21 February 2006 diurnal and semi-diurnal tidal band's residual gravity components were analyzed. During this process, the instrumental noises, air pressure, and ground water corrections were carried out. Values of $-3.18nm/s^2/hPa\;and\;17nm/s^2/m$ were used respectively in the air pressure and groundwater corrections. Hartmann-Wenzel and Whar-Dehant Earth tide models were adopted to compute the residual gravity for Q1, O1, P1, K1, M2, N2, S2, K2 tidal bands. For the ocean loading correction, SCW80, FES952, and FES02 models were used and compared. As a result, FES02 ocean loading model has shown the best match for the data processing at MunGyung SG MunGyung SG gravity was compared with GRACE satellite gravity. The correlation coefficient between the two gravity after groundwater correction was 0.628, which is higher than before ground water correction. To evaluate sensitivity at MunGyung SG gravity statition, the gravity data measured during 2005 Indodesian earthquake was compared with STS-2 broad band seismometer data. The result clearly revealed that the SG could recorded the same period of earthquake with seismometer event and a few after-shock events those were detected by seismometer. 2005년 3월 경상북도 문경에 설치된 초전도 중력계가 Global Geodynamics Project에 세계 21번째 관측소로 등록되어 현재 정상 운영 중에 있다. 미세한 중력변화를 1mHZ 이하의 저주파 영역에서 $10^{-2}nm/s^2$ 수준의 뛰어난 분해능으로 측정하는 초전도 중력계는 지구 중력의 다양한 주기의 지구중력변화를 감지하고 분석하는데 매우 효과적이다. 문경 초전도 중력 자료의 기초 분석을 위하여 2005년 3월 18일 부터 2006년 2월 21일 사이의 자료를 이용하여 일일주기와 반일주기 성분의 잔여중력을 계산하였다. 기계적 잡음을 제거한 후 기압 및 지하수 보정을 실시하였고, Hartmann-Wenzel 모델과 Whar-Dehant 모델을 이용하여 지구 조석을 보정하였으며 SCW80, FES952, FES2002 해양모델을 이용하여 ocean loading의 영향을 보정하였다. 초전도 중력자료의 신뢰도 검증을 위해 GRACE 인공위성에서 관측된 중력과 비교한 결과, 0.63의 상관관계를 보였다. 한편 2005년 발생한 인도네시아의 수마트라 지진자료를 광대역 지진계(STS-2)자료와 비교한 바, 지진계에서 관측되는 지진신호 및 여진이 감지됨을 확인할 수 있었다.

Determination of gravity at MunGyung (Mungyeong) superconducting gravity observatory, Korea

김기동,Jeong Woo Kim,Juergen Neumeyer,Ricky Kao,Cheinway Hwang,박혁진,Ik Woo,Young Wook Lee 한국지질과학협의회 2009 Geosciences Journal Vol.13 No.2

Absolute gravity measurements were made to calibrate Korea’s first superconducting gravimeter (SG) at MunGyung (MG, Mungyeong) Observatory. A calibration coefficient (CC) of the MG SG was determined by a parallel registration with an FG5 absolute gravimeter. A total of 8,541 drops were measured over a period of 37 hours between October 8th and 10th, 2007. We first determined the absolute gravity value to be 979,859,179.3 ± 88.481 μGal (μGal=10−8 m·s−2) after atmospheric pressure, Earth tide and ocean loading corrections. In a linear regression analysis between the FG5 recordings and the raw SG data, a CC of 64.548 ± 0.224 μGal· volt–1 was determined, having previously removed invalid drops and outliers from the data sets. Together with the absolute measurements, a vertical gravity gradient of 2.72 μGal·cm–1 was calculated using a Graviton-EG spring gravimeter to take the absolute gravity value down to the SG observatory platform level. The validity of the CC was additionally tested by a comparison between the recorded SG data and the theoretical tides (HW95 and Wahr-Dehant models) as reference. Gravity variations induced by atmospheric pressure and ocean loading were added to the theoretical Earth tides. The CC based on the theoretical tide was determined to be 64.560 μGal·volt–1. The difference between the two coefficients is 0.012 μGal· volt–1, which lies within the standard error of the determined coefficient, 0.224 μGal·volt–1. Therefore, a value of 64.548 μGal·volt–1, determined by the parallel registration with the absolute gravimeter, was accepted as the CC of the SG (GWR Instrument Inc. #045) installed at MG Observatory. During the gravity measurements, the other gravity values and heights such as normal gravity and the gravity gradient, orthometric and dynamic heights were also calculated Absolute gravity measurements were made to calibrate Korea’s first superconducting gravimeter (SG) at MunGyung (MG, Mungyeong) Observatory. A calibration coefficient (CC) of the MG SG was determined by a parallel registration with an FG5 absolute gravimeter. A total of 8,541 drops were measured over a period of 37 hours between October 8th and 10th, 2007. We first determined the absolute gravity value to be 979,859,179.3 ± 88.481 μGal (μGal=10−8 m·s−2) after atmospheric pressure, Earth tide and ocean loading corrections. In a linear regression analysis between the FG5 recordings and the raw SG data, a CC of 64.548 ± 0.224 μGal· volt–1 was determined, having previously removed invalid drops and outliers from the data sets. Together with the absolute measurements, a vertical gravity gradient of 2.72 μGal·cm–1 was calculated using a Graviton-EG spring gravimeter to take the absolute gravity value down to the SG observatory platform level. The validity of the CC was additionally tested by a comparison between the recorded SG data and the theoretical tides (HW95 and Wahr-Dehant models) as reference. Gravity variations induced by atmospheric pressure and ocean loading were added to the theoretical Earth tides. The CC based on the theoretical tide was determined to be 64.560 μGal·volt–1. The difference between the two coefficients is 0.012 μGal· volt–1, which lies within the standard error of the determined coefficient, 0.224 μGal·volt–1. Therefore, a value of 64.548 μGal·volt–1, determined by the parallel registration with the absolute gravimeter, was accepted as the CC of the SG (GWR Instrument Inc. #045) installed at MG Observatory. During the gravity measurements, the other gravity values and heights such as normal gravity and the gravity gradient, orthometric and dynamic heights were also calculated

Adsorption of Indigo Carmine from Aqueous Solution by Chitosan and Chitosan/Activated Carbon Composite: Kinetics, Isotherms and Thermodynamics Studies

Jacques K. Fatombi,Esta A. Idohou,Sèmiyou A. Osseni,Ignace Agani,David Neumeyer,Marc Verelst,Robert Mauricot,Taofiki Aminou 한국섬유공학회 2019 Fibers and polymers Vol.20 No.9

Activated carbon (AC) obtained from peanut shell, chitosan (CH) obtained from crab shell, and prepared chitosan/activated carbon (CH/AC) composite were studied in a batch system for the adsorption of indigo carmine (IC) from aqueoussolution. Characterizations of AC, CH, and CH/AC were investigated by FTIR, SEM, XRD, zero-point charge pHpzc,thermal analysis, surface area BET, and pore-size distribution. Adsorbent weight (0.01-0.1 g), initial pH solution (2-10),initial indigo carmine concentration (10-50 mg/l) and contact time (0-60 min) were used as parameters in the adsorptionequilibrium experiments. Pseudo-second-order kinetic model was found to describe the adsorption process better thanpseudo-first-order kinetic model. Langmuir, Freundlich, and Temkin isotherms applied to the adsorption data reveal that ACand CH/AC best fitted Langmuir and Freundlich models when CH data fitted Temkin model with maximum adsorptioncapacities of 82.64 mg/g for AC, 96.15 mg/g for CH, and 208.33 mg/g for CH/AC at 30 oC. Thermodynamic parameters suchas standard Gibbs free energy (ΔGo), standard enthalpy (ΔHo), and standard entropy (ΔSo) were -23.42 kJ/mol, 10.66 kJ/mol,and 112.40 J/K/mol, respectively for CH/AC. The negative value of ΔGo and a positive value of ΔHo indicate that theremoval of indigo carmine by CH/AC is spontaneous and an endothermic process.