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Evaluation of SrBr₂ Hydration Reaction Rate with Repeated Cycling

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Journal of Materials Science and Chemical Engineering 2022年第2期10卷 53-61页

作者： Takehiro Esaki yuichi sugai Department of Earth Resources Engineering Kyushu University Fukuoka Japan

In this study, we evaluated the SrBr2 hydration reaction rate on repeated cycling. It was estimated that hydrated SrBr2 particles were expanded by hydration and condensed to form secondary particles;thus, the hydration reaction was reduced by repeated cycles. Using volumetric methods, we examined the effect of repetition on the reaction rate for 900 cycles during hydration and dehydration and analyzed the reaction rate using the unreacted core-shell model. From the experimental and calculated results, we confirmed that reaction rate decreased and the sample particles formed secondary particles after 900 repeated cycles. By analyzing the unreacted core-shell model, we found that the coefficient of H2O diffusion in the particles exponentially decreased with increasing repeated cycles. The value of the diffusion coefficient after 900 cycles was five times lower than that of the first cycle. To achieve stable repeated hydration cycles, technology to control the formation of secondary particles must be investigated.

关键词： SrBr2 Hydration Repetition Cycle The Coefficient of Particle Diffusion

Textural Characteristics and Depositional Environment of Ngrayong Sandstone (Middle Miocene) from Rembang Area, Northeast Java, Indonesia

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Open Journal of Geology 2022年第12期12卷 1102-1119页

作者： San Yee Khaing yuichi sugai Myo Min Tun Sugeng Sapto Surjono Jarot Setyowiyoto Department of Geology Kyaing Tong University Kyaing Tong Myanmar Department of Earth Resource Engineering Faculty of Engineering Kyushu University Fukuoka Japan Ministry of Education Office No. 13 Nay Pyi Taw Myanmar Department of Geological Engineering Faculty of Engineering Gadjah Mada University Yogyakarta Indonesia

Granulometric analysis of Ngrayong sandstone samples from Rembang area of NE Java (Indonesia) has been carried out to examine the textural characteristics and elucidate depositional environment. The result data from the grain size analysis indicates that the Ngrayong sediments are classified as sand or muddy sands. They are very fine- to medium-grained (phi values: 1.67 to 3.35), moderately- to well-sorted (standard deviation: 0.19 to 0.57), strongly fine-skewed to strongly coarse-skewed (skewness values: 4.82 to −5.97), and very platykurtic to very leptokurtic (kurtosis values: 0.36 to 2.41). Sandstone samples show unimodal grain size distribution. The sediments are interpreted to be transported in all three modes-traction, saltation and suspension, however, suspension and rolling are the major processes during transportation. Discriminant functions indicate diversity in the depositional environment for the sandstones. However, shallow marine is regarded as the dominant depositional environment. The preponderance of fine-grained sediments and lack of coarse sands suggest low to moderate energy conditions during deposition of Ngrayong sediments.

关键词： Granulometric Analysis Ngrayong Sandstone Rembang Textural Characteristics Depositional Environment

Numerical simulation to evaluate gas diffusion of turbulent flow in mine ventilation system

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International Journal of Mining Science and Technology 2013年第3期23卷 349-355页

作者： Arif Widiatmojo Kyuro Sasaki Nuhindro Priagung Widodo yuichi sugai Johannes Sinaga Haris Yusuf Department of Earth Resources Engineering Graduate School of EngineeringKyushu University Department of Mining Engineering Faculty of Mining and Petroleum EngineeringInstitut Teknologi Bandung PT. Cibaliung Sumberdaya Pandeglang

Tracer gas technique is a method to analyze the airflow path, measure the airflow quantity, and detect any recirculation or leakages in underground mine. In addition, it is also possible to evaluate the axial gas diffusion of gas in turbulent bulk flow by utilizing the tracer gas data. This paper discussed about the measurement using tracer gas technique in Cibaliung Underground Mine, Indonesia and the evaluation of effective axial diffusion coefficient, E, by numerical simulation. In addition, a scheme to treat network flow in mine ventilation system was also proposed. The effective axial diffusion coefficient for each airway was evaluated based on Taylor's theoretical equation. It is found that the evaluated diffusion coefficient agrees well with Taylor's equation by considering that the wall friction factor, f, is higher than those for smooth pipe flow. It also shows that the value of effective diffusion coefficient can be inherently determined and the value is constant when matching with other measurements. Furthermore, there are possibilities to utilize the tracer gas measurement data to evaluate the airway friction factors.

关键词： Tracer gas Effective axial diffusion coefficient Mine ventilation Numerical simulation

Swelling Measurements of a Low Rank Coal in Supercritical CO<sub>2</sub>

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International Journal of Geosciences 2013年第5期4卷 863-870页

作者： Ferian Anggara Kyuro Sasaki yuichi sugai 1Department of Earth Resources Engineering Kyushu University Fukuoka Japan 2Department of Geological Engineering Gadjah Mada University Yogyakarta Indonesia Department of Earth Resources Engineering Kyushu University Fukuoka Japan

Coal swelling in the presence of water as well as CO2 is a well-known phenomenon, and these may affect the permeability of coal. Quantifying swelling effects is becoming an important issue to verify the suitability of particular coal seams for CO2-enhanced coal bed methane recovery projects. In this report, coal swelling experiments using a visualization method in the CO2 supercritical conditions were conducted on crushed coal samples. The measurement apparatus was designed specifically for the present swelling experiment using a visualization method. Crushed coal samples were used instead of block coal samples to shorten equilibrium time and to solve the problem of limited availability of core coal samples. Dry and wet coal samples were used in the experiments because there is relatively limited information about how the swelling of coal by CO2 is affected by water saturation. Moreover, some coal seams are saturated with water in initial reservoir conditions. The maximum volumetric swelling was around 3% at 10 MPa for dry samples and almost half that at the same pressure for wet samples. The wet samples showed lower volumetric swelling than dry ones because the wet coal samples were already swollen by water. Experimental results obtained for swelling were comparable with other reports. Our visualization method using crushed samples has advantages in terms of sample preparation and experimental execution compared with the other methods used to measure coal swelling using block samples.

关键词： Coal Swelling Experiments Visualization Method CO2-Enhanced Coal Bed Methane Recovery Low Rank Coal

Gas Production from Offshore Methane Hydrate Layer and Seabed Subsidence by Depressurization Method

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Engineering（科研） 2016年第6期8卷 353-364页

作者： Hiroki Matsuda Takafumi Yamakawa yuichi sugai Kyuro Sasaki Department of Earth Resources Engineering Kyushu University Fukuoka Japan

Numerical simulations on consolidation effects have been carried out for gas production from offshore methane hydrates (MH) layers and subsidence at seafloor. MH dissociation is affected by not only MH equilibrium line but also consolidation (mechanical compaction) depended on depressurization in the MH reservoir. Firstly, to confirm present model on consolidation with effective stress, the history matching on gas production and consolidation has been done to the experimental results using with synthetic sand MH core presented by Sakamoto et al. (2009). In addition, the comparisons of numerical simulation results of present and Kurihara et al. (2009) were carried out to check applicability of present models for gas production from MH reservoir in field scale by depressurization method. The delays of pressure propagation in the MH reservoir and elapsed time at peak gas production rate were predicted by considering consolidation effects by depressurization method. Finally, seabed subsidence during gas production from MH reservoirs was numerically simulated. The maximum seabed subsidence has been predicted to be roughly 0.5 to 2 m after 50 days of gas production from MH reservoirs that elastic modulus is 400 to 100 MPa at MH saturation = 0.

关键词： Methane Hydrate Offshore Gas Production Consolidation Subsidence Depressurization

Experimental Study on Seismic Attenuation and Permeability of Large Porosity Rock

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Journal of Geoscience and Environment Protection 2018年第5期6卷 80-90页

作者： Xiaochen Yang Kyuro Sasaki Xiaoming Zhang yuichi sugai Department of Earth Resources Engineering Kyushu University Fukuoka Japan Institute of Engineering and Environment Liaoning Technical University Huludao China

The large porosity areas widely present in the underground resulting from natural hazards or artificial damages. The porosity and permeability are suggested to be capable of estimating the mechanical and air flow conditions inside the porous layer in the underground. To accurately measure the porosity and permeability in the porous area is imperative. To address this issue, we experimentally modeled some porous samples in large porosities by using sandstone particles sieved to different sizes. Ultrasonic was employed to apply on the porous sandstone samples to characterize the seismic velocity and attenuation. Permeability was also measured simultaneously to find a correlation with the porosity. The results showed the seismic attenuation decrease as the reduction of frequency and increasing particle size at the same porosity. Seismic attenuation was strongly correlated to porosity and particle size. Velocity showed a good relationship with the porosity change. Permeability was highly dependent on the particle size especially in the higher porosity range. The results indicated that it is possible to find a relationship between the permeability and seismic attenuation via the porosity and particle size.

关键词： Porous Area Ultrasonic Measurement Seismic Attenuation Porosity Permeability

Discrete Tracer Point Method to Evaluate Turbulent Diffusion in Circular Pipe Flow

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Journal of Flow Control, Measurement & Visualization 2013年第2期1卷 57-68页

作者： Arif Widiatmojo Kyuro Sasaki Nuhindro Priagung Widodo yuichi sugai Department of Earth Resources Engineering Faculty of Engineering Kyushu University Fukuoka Japan Department of Mining Engineering Faculty of Mining and Petroleum EngineeringInstitut Teknologi Bandung Bandung Indonesia

Diffusion of a solute in turbulent flows through a circular pipe or tunnel is an important aspect of environmental safety. In this study, the diffusion coefficient of turbulent flow in circular pipe has been simulated by the Discrete Tracer Point Method (DTPM). The DTPM is a Lagrangian numerical method by a number of imaginary point displacement which satisfy turbulent mixing by velocity fluctuations, Reynolds stress, average velocity profile and a turbulent stochastic model. Numerical simulation results of points’ distribution by DTPM have been compared with the analytical solution for turbulent plug-flow. For the case of turbulent circular pipe flow, the appropriate DTPM calculation time step has been investigated using a constantβ, which represents the ratio between average mixing lengths over diameter of circular pipe. The evaluated values of diffusion coefficient by DTPM have been found to be in good agreement with Taylor’s analytical equation for turbulent circular pipe flow by givingβ=0.04 to 0.045. Further, history matching of experimental tracer gas measurement through turbulent smooth-straight pipe flow has been presented and the results showed good agreement.

关键词： Discrete Tracer Point Method (DTPM) Turbulent Diffusion Pipe Numerical Simulation Airflow

Facies and Reservoir Characteristics of the Ngrayong Sandstone in the Rembang Area, Northeast Java (Indonesia)

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Open Journal of Geology 2017年第5期7卷 608-620页

作者： San Yee Khaing Sugeng Sapto Surjono Jarot Setyowiyoto yuichi sugai Department of Earth Resource Engineering Faculty of Engineering Kyushu University Fukuoka Japan Geological Engineering Department Faculty of Engineering Gadjah Mada University Yogyakarta Indonesia

The Rembang area is a well-known prospective region for oil and gas exploration in Northeast Java, Indonesia. In this study, the reservoir characteristics of the Ngrayong Sandstone were investigated based on outcrops in the Rembang area. Petrological, mineralogical, petrophysical and sedimentological facies analyses were conducted. These sandstones are grain- and matrix-supported, and composed of very fine to medium, sub-angular to poorly-rounded, moderately- to very well-sorted sand grains. These sandstones are mainly composed of quartz, orthoclase, plagioclase, and micas with minor amounts of clay minerals, and therefore are predominantly classified as sub-lithic arenite and sub-felds pathicarenite. Petrographic observations and grain size data indicate that these sandstones are texturally quite mature, based on their good-sorting and the occurrence of minor amounts of matrix clays. Common clays in the samples include illite, smectite, kaolinite, and gibbsite. The porosity of the Ngrayong sandstones ranges from 25.97% to 40.21%, and the permeability ranges from 94.6 to 3385 millidarcies. Thus, these sandstones exhibit well to excellent reservoir qualities. Eight lithofacies were identified from five measured stratigraphic sections, and are dominated by foreshore and tide-dominated shoreface facies. The Ngrayong sequence shows a single transgressive-regressive cycle. Cross-bedded sandstone and massive sandstone are identified as the most promising potential reservoir facies based on their characteristics in outcrops, their lateral and vertical distributions, their sedimentological characteristics and their petrophysical properties.

关键词： Reservoir Characteristics Facies Analysis Permeability Hydrocarbon Exploration

Visualizing the hepatic vascular architecture using superb microvascular imaging in patients with hepatitis C virus: A novel technique

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World Journal of Gastroenterology 2016年第26期22卷 6057-6064页

作者： Hidekatsu Kuroda Tamami Abe Keisuke Kakisaka Yudai Fujiwara yuichi Yoshida Akio Miyasaka Kazuyuki Ishida Hideaki Ishida Tamotsu sugai Yasuhiro Takikawa Division of Hepatology Department of Internal Medicine Iwate Medical University School of Medicine Department of Molecular Diagnostic Pathology Iwate Medical University Center of Diagnostic Ultrasound Akita Red Cross Hospital

AIM: To identify the hepatic vascular architecture of patients with hepatitis C virus(HCV) using superb microvascular imaging(SMI) and investigate the use of SMI in the evaluation of liver ***: SMI was performed in 100 HCV patients. SMI images were classified into five types according to the vascular pattern, and these patterns were compared with the fibrosis stage. Moreover, the images were analyzed to examine vascularity by integrating the number of SMI signals in the region of interest ROI [number of vascular trees(VT)]. The number of VT, fibrosis stage, serum parameters of liver function, and CD34 expression were ***: There was a significant difference between SMI distribution pattern and fibrosis stage(P < 0.001). The mean VT values in each of the fibrosis stages were as follows: 26.69 ± 7.08 in F0, 27.72 ± 9.32 in F1, 36.74 ± 9.23 in F2, 37.36 ± 5.32 in F3, and 58.14 ± 14.08 in F4. The VT showed excellent diagnostic ability for F4 [area under the receiver operator characteristic(AUROC): 0.911]. The VT was significantly correlated with the CD34 labeling index(r = 0.617, P < 0.0001).CONCLUSION: SMI permitted the detailed delineation of the vascular architecture in chronic liver disease. SMI appears to be a reliable tool for noninvasively detecting significant fibrosis or cirrhosis in HCV patients.

关键词： Superb microvascular imaging Number of vascular trees Chronic liver disease Ultrasound Liver fibrosi