Measurement and Control System in Process of Carbon Dioxide Capture Based on Sparse Support Vector Machine

With the increasing shortage of timber resources and the advancement of environmental protection projects, many artificial fast-growing forests are planted and used as raw materials in China. There are significant differences in the properties of natural forest wood and artificial fast-growing forest wood, and the properties of wood mainly depend on the change in the status of bound water in the cell wall. In this study, the fiber saturation point (FSP) and pore size distributions within the cell wall of six species of fast-growing forest wood were studied by low-temperature nuclear magnetic resonance (NMR) technology. The effects of species, growth rings, and extractives on the FSP and pore structure were analyzed. The water vapor sorption experiments were performed, and the adsorption isotherms of the samples were fitted through the Guggenheim-Anderson-de Boer (GAB) equation. According to the least-square regression of the adsorption isotherms and combined with the low-temperature NMR experiments, the content and proportion of the different types of bound water were analyzed. The results showed that the average FSP of each Chinese fir was about 40% and that of each poplar was about 35%. There is about a 10% difference between the FSP measured by NMR technology and the adsorption bound water content obtained by adsorption isothermal. The pore size distribution results show that in all samples, the proportion of pores larger than 10.5 nm is very low, about 10%; the proportion of 1.92-10.5 nm pores is about 30%; and the proportion of pores smaller than 1.92nm is more than 50%. This work will be helpful to the study of the wood moisture status and provide reference data for wood modification.

Effective common spatial pattern (CSP) feature extraction for motor-imagery (MI) EEG recordings usually depends on the filter band selection to a large extent. However, the most proper filter band can hardly be determined manually due to its subject-specific property. This study introduces a sparse support vector machine (SSVM) approach to implement simultaneous CSP feature selection and classification for MI-based brain–computer interface (BCI). In SSVM, CSP features are first extracted on multiple signals that are filtered from raw EEG data at a set of overlapping subbands. SVM with l 1-norm regularization is then proposed to classify MI tasks with automatic selection of filter bands giving the significant CSP features. The effectiveness of SSVM for MI classification is demonstrated on the BCI Competition III dataset IVa, in comparison with several other competing methods. Experimental results indicate that the proposed SSVM method is promising for development of an improved MI-based BCI.

A review of nuclear magnetic resonance (NMR) technology applied in the characterization of polymer gels for petroleum reservoir conformance control

Several light oil and gas reservoirs are present within an extensive Permian clastic sequence in the Middle East. Well logs and core data revealed numerous challenges for the petrophysical description of this formation. Rapidly changing depositional environments and diagenetic effects caused heterogeneities in grain size and sorting within clean sands. Consequently, gamma ray and conventional porosity logs have little sensitivity to rock quality variations. Secondly, an influx of meteoric water into the reservoir rocks decreased formation water salinities which adds uncertainties to the estimation of fluid saturations from resistivity logs. Finally, gas-oil contacts are present in some reservoirs where log-based in-situ hydrocarbon typing is of great practical value. The introduction of nuclear magnetic resonance (NMR) logs has successfully mitigated these issues as evidenced by petrophysical interpretations and formation testing in the area's exploration and delineation wells. Lateral facies variations and complicated reservoir structures warranted the deployment of NMR technology in horizontal development wells for better well placement and completion optimization with logging while drilling (LWD) NMR as the most preferable option. The NMR logs led geosteering decisions and proactive well planning to singificantly increase reservoir contacts in producer wells. Permeability predicted by the NMR logs is of great value in real-time well placement decisions and completion design including ICD installations. The low-gradient LWD NMR measurement gives rise to a very simple and robust real-time fluid identification thanks to the the good separation of water and oil signals in the NMR T2 spectrum. This fluid quantification, combined with bound fluid analysis, helps determine the well's position in the transition zone by detecting free water. This paper summarizes the experience with both wireline and LWD NMR technologies in the area. Lessons learned include considerations for deployment, tool activations and NMR interpretation.

In order to explore the change characteristics of the adsorption and desorption performance of coal under high gas pressure, low-field nuclear magnetic resonance (LFNMR) technology was used to conduct experimental research on coal adsorption and desorption. The results show that (1) the T 2 spectrum distribution diagram shows adsorption peaks ( T 2 = 0.01 ms ~ 1 ms ) and free peaks ( T 2 = 5 ms ~ 1000 ms ); (2) with the increase of equilibrium pressure, the peak area of adsorbed methane gradually increased at first and then tended to equilibrium. The initial increase rate of free methane was slower than that of adsorbed methane, and the increase rate of free methane was faster in the later stage; (3) the relationship between the amount of adsorbed gas in the adsorption state of coal and the gas pressure conforms to the Langmuir equation. Taking the equilibrium pressure P = 8.7 MPa as the critical hysteresis pressure, it can be divided into two stages which are higher gas pressure (0.5~8.7 MPa) and high gas pressure (8.7~10.33 MPa); the amount of adsorbed gas in the free state has a linear relationship with the gas pressure, and there is no obvious hysteresis; (4) comparative analysis under the same experimental conditions, the mass of the adsorbed gas in the desorption process is greater than the mass of the adsorbed gas in the adsorption process, and there is basically no difference in the mass of the free gas.

Characterization of mechanical properties and microstructure of silica mortar and coral mortar based on nuclear magnetic resonance technology

Freeze-thaw damage evolution of fractured rock mass using nuclear magnetic resonance technology

“Fracturing network+imbibition oil production” is a new attempt to effectively develop low-permeability tight reservoirs. Fracturing fluid is not only a carrier for sand carrying but also a tool in the process of imbibition. On the basis of imbibition experiments, combined with nuclear magnetic resonance and pseudo-color processing technology, this paper clarified the dominant forces of different types of pore-throat and quantitatively characterized the contribution of different levels of pore-throat to imbibition oil recovery. The results show that gravity is the main controlling force of imbibition for reservoirs with higher permeability. Fluid replacement mainly occurs in the early period of imbibition. Macropores contribute most of the imbibition recovery, mesopores have a weak contribution, and the contribution of micropores and pinholes can be ignored. For the reservoirs with low permeability, capillary force is the main controlling force of imbibition. Fluid replacement mainly occurs in the later period of imbibition. Macropores contribute most of the imbibition recovery rate, mesopores contribute a small part of the imbibition recovery factor, and the contribution of micropores and pinholes can be ignored. This paper clarified that macropores and mesopores are the main sources of the contribution of imbibition recovery efficiency, and oil content and connectivity are key factors for the imbibition recovery efficiency.

A nuclear magnetic resonance advance. Imaging fluorinated anesthetics in the brain.

Nuclear magnetic resonance (NMR) is a powerful technique for the structure elucidation of organic molecules and significantly important in the pharmaceutical industry supporting the discovery and development of drug substances or active pharmaceutical ingredients (APIs). Following an initial study and assessment of a prototype NMR instrument with a high-temperature superconducting (HTS) power-driven magnet of 9.4 T (400 MHz for 1H observation) operating with standard commercial electronics and probes, we tested the instrument with three compounds representing typical pharmaceutical drugs. We compared results from two probes and shimstacks with different geometries (broadband fluorine observe (BBFO) with Bruker orthogonal shim system-3 (BOSS3) and Bruker quattro nucleus probe (QNP) with BOSS1 shims) testing standard one-dimensional (1D) NMR experiments including selective excitation experiments, and two-dimensional (2D) homonuclear and heteronuclear experiments for the purposes of evaluating the equipment for structure elucidation capabilities. In our initial study on cinacalcet HCl, only the 1D 1H experiment showed a loss of resolution when using the longer coiled BBFO probe with the BOSS3 shims compared to the shorter coiled QNP probe with BOSS1 shims. The selective excitation experiments using the cinacalcet HCl were successful. Our characterization of 1D (1H, 13C, 19F) and 2D (1H-1H and 1H-13C) NMR experiments for compounds I and II with the two probes and shimstacks indicated no significance differences. Overall, these results are satisfactory with the HTS magnet at the field of 9.4 T for the structural elucidation work of standard pharmaceutical compounds. This new technology has the advantage of being able to locate the HTS NMR magnet system in any chemistry or analytical laboratory where the samples are produced, facilitating rapid analysis with minor needs from the facilities and without cryogenic liquids.

Cells, drugs and NMR.

13] 1H NMR spectroscopy of DNA

Nuclear magnetic resonance (NMR) and magnetic susceptibility (MS) borehole logging measurements were collected at the Rifle Integrated Field Research Challenge (IFRC) site. The Rifle IFRC site is located at a former uranium ore‐processing facility in Rifle, Colorado. Although removed from the site by 1996, leachate from spent mill tailings has resulted in residual uranium contamination of both groundwater and sediments within the local aquifer. Since 2002, research at the site has primarily focused on quantifying uranium mobility associated with stimulated biogeochemical processes. Ongoing studies at the site include an acetate amendment strategy, in which stimulation of native microbial populations by introduction of a carbon source serves to alter local redox conditions, and immobilization of uranium in insoluble forms. NMR and MS logging measurements were taken before, during, and after acetate amendment. Changes in these signals are expected to correlate with changes in redox conditions and iron speciation thus potentially allowing their use as a non‐invasive tool for monitoring bioremediation. Experimental data was collected from two wells upstream of the acetate amendment, used as controls, and from three downstream wells. The MS measurements revealed vertically stratified magnetic mineralization, likely the result of a detrital magnetic fraction within the bulk alluvium. Data were highly replicable over the monitoring interval, with little to no change observed in the MS measurements, suggesting negligible production of magnetic phases (e.g. magnetite, pyrrhotite) as a result of enhanced microbial activity. NMR measurements had high levels of noise contamination requiring significant signal processing, and ongoing analysis suggests that any changes due to enhanced microbial activity may be difficult to differentiate from simultaneous changes in water content.

Knowledge of the permeability distribution is critical to a successful reservoir model. Nuclear Magnetic Resonance (NMR) measurements can be used for permeability prediction because the T2 relaxation time is proportional to pore size. Due to the conventional estimators have difficult and complex problems in simulating the relationship between permeability and NMR measurements, an intelligent technique using artificial neural network and genetic algorithm to estimate permeability from NMR measurements is developed. Neural network is used as a nonlinear regression method to develop transformation between the permeability and NMR measurements. Genetic algorithm is used for selecting the best parameters and initial value for the neural network, which solved two major problems of the network: local minima and parameter selection depend on experience. Information gain principle is introduced to select the neural network's input parameters automatically from data. The technique is demonstrated with an application to the well data in Northeast China. The results show that the refined technique make more accurate and reliable reservoir permeability estimation compared with conventional methods. This intelligent technique can be utilized a powerful tool for estimate permeability from NMR logs in oil and gas industry.

Solution-phase synthesis of buckybowls remains a big challenge, and there are limited reports on the fragments of C70. Herein, we report a new basic subunit of C70 with C2v symmetry, the dicyclopenta[4,3,2,1- ghi:4',3',2',1'- pqr]perylene (2CP-Per). Its aryl-substituted derivative 2CP-Per-Ar was synthesized and shows a bowl-shaped geometry according to X-ray crystallographic analysis. A fast bowl-to-bowl inversion process was observed above 183 K by variable temperature nuclear magnetic resonance (NMR), with a small inversion energy barrier. 2CP-Per-Ar displays amphoteric redox behavior with a small electrochemical energy gap (1.29 eV). Different from many other aromatic buckybowls, 2CP-Per exhibits global antiaromaticity with a strong paratropic ring current associated with the 16π-electrons rim, as revealed by NMR measurements and theoretic calculations. Its dianion is aromatic, similar to its isoelectronic structure coronene. Its dication is predicted to be aromatic, with a [6]annulene-within-[14]annulene structure.