Investigation of CO2 storage capacity in open saline aquifers with numerical models

AbstractAccurate calculation of carbon dioxide (CO2) storage capacity in deep saline aquifers is a challenging task. However an assessment must be performed to determine whether there is sufficient capacity in a storage site for any CO2 sequestration project. We evaluated the CO2 storage capacity for a simplified reservoir system, which the layered potential storage formations are overlaid by sealing cap rock. This study aims at determining CO2 storage capacity for the injection of CO2 in opened saline formations using numerical simulation method. In this study, a 3D numerical model was developed for the investigation. Detailed processes for the storage capacity estimation are derived. The impact of injection strategy and the residual gas saturation on storage capacity was investigated. It is shown that both of the injection strategy and the residual gas saturation have a great impact on the spatial distribution of CO2 plume and the effective storage of CO2 in the reservoir. Simulation results also indicate that the injection well distribution may significantly influence the use of the formation porous space for CO2 storage. From this study, we may conclude that the most accurate way to estimate storage capacity is through construction of a basin scale three-dimensional numerical model for specific storage site by incorporating detailed geological information of the site and injection scheme used

Carbon nanotubes/magnetite hybrids prepared by a facile synthesis process and their magnetic properties

In this paper, a facile synthesis process is proposed to prepare multiwalled carbon nanotubes/magnetite (MWCNTs/Fe3O4) hybrids. The process involves two steps: (1) water-soluble CNTs are synthesized by one-pot modi. cation using potassium persulfate (KPS) as oxidant. (2) Fe3O4 is assembled along the treated CNTs by employing a facile hydrothermal process with the presence of hydrazine hydrate as the mineralizer. The treated CNTs can be easily dispersed in aqueous solvent. Moreover, X-ray photoelectron spectroscopy (XPS) analysis reveals that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups are formed on the nanotube surfaces. The MWCNTs/Fe3O4 hybrids are characterized with respect to crystal structure, morphology, element composition and magnetic property by X-ray diffraction (XRD), transmission electron microscopy (TEM), XPS and superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the Fe3O4 nanoparticles with diameter in the range of 20-60 nm were firmly assembled on the nanotube surface. The magnetic property investigation indicated that the CNTs/Fe3O4 hybrids exhibit a ferromagnetic behavior and possess a saturation magnetization of 32.2 emu/g. Further investigation indicates that the size of assembled Fe3O4 nanoparticles can be turned by varying experiment factors. Moreover, a probable growth mechanism for the preparation of CNTs/Fe3O4 hybrids was discussed.ArticleAPPLIED SURFACE SCIENCE. 255(20):8676-8681 (2009)journal articl

One-step preparation of water-soluble single-walled carbon nanotubes

A novel one-step process using potassium persulfate (KPS) as oxidant is proposed in this paper to prepare water-soluble single-walled carbon nanotubes (SWNTs). The process without the need for organic solvents and acids is a low-cost, eco-friendly, facile method. Morphology observation by atomic force microscopy (AFM) indicates that the KPS-treated SWNTs were effectively debundled without obvious shortening in their length. The functional groups and thermal stability of the treated SWNTs were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). XPS results show that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups were formed on the surfaces of the SWNTs, while the TGA results reveal that the quantity of the functional groups can reach to approximately 20%.ArticleAPPLIED SURFACE SCIENCE. 255(15):7095-7099 (2009)journal articl

Initial design with L2 Monge-Kantorovich theory for the Monge–Ampère equation method of freeform optics

The Monge–Ampère (MA) equation arising in illumination design is highly nonlinear so that the convergence of the MA method is strongly determined by the initial design. We address the initial design of the MA method in this paper with the L2 Monge-Kantorovich (LMK) theory, and introduce an efficient approach for finding the optimal mapping of the LMK problem. Three examples, including the beam shaping of collimated beam and point light source, are given to illustrate the potential benefits of the LMK theory in the initial design. The results show the MA method converges more stably and faster with the application of the LMK theory in the initial design

Why Is Maternal Control Harmful? The Relation between Maternal Control, Insecure Attachment and Antisocial Personality Disorder Features in Chinese College Students:A Sequential Mediation Model

Background: Previous work has indicated that a negative parenting style is associated with antisocial personality disorder features in Chinese college students, yet few studies have explored the unique role of negative mothering in children’s antisocial personality disorder. Methods: The current study mainly examined the sequential mediation effect of parental antipathy and neglect (PAN) and mother negative loving (a form of insecure attachment) in the association between mother control and adulthood antisocial personality disorder features (ASPD features) in the framework of attachment theory and cognitive–behavioral theory. A community sample of 1547 Chinese college students filled in the Parental Bonding Instrument, the Childhood Experience of Care and Abuse Questionnaire, the Adult Attachment Questionnaire and the Personality Diagnostic Questionnaire-4+. Results: A sequential mediation model analysis showed that maternal control significantly predicted PAN, mother negative loving, as well as ASPD features. Conclusions: Mother control and mother negative loving appear to advance on the development and exacerbation of ASPD features in college students

Synthesis and Mechanical Properties of Polybenzimidazole Nanocomposites Reinforced by Vapor Grown Carbon Nanofibers

This is a preprint of an article published in Polymer Composites. 31(3):491-496 (2010) JOHN WILEY & SONS INC URL: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1548-0569Polybenzimidazole (PBI) nanocomposites containing 0.5-5 wt% vapor grown carbon nanofibers (VGNFs) were successfully synthesized by solvent evaporation method. Fracture morphology examination confirmed the uniform dispersion of VGNFs in the matrix. The mechanical properties of neat PBI and the nanocomposites were systematically measured by tensile test, dynamic mechanical analysis (DMA), hardness measurement, and friction test. Tensile tests revealed that Young's modulus increased by about 43.7% at 2 wt% VGNFs loading, and further modulus growth was observed at higher filler loadings. DMA studies showed that the nanocomposites have higher storage modulus than neat PBI in the temperature range of 30-350 degrees C, holding storage modulus larger than 1.54 GPa below 300 degrees C. Outstanding improvement of hardness was achieved for PBI upon incorporating 2 wt% of VGNFs. The results of friction test showed that coefficient of friction of PBI nanocomposites decreased with VGNFs content compared with neat PBI.ArticlePOLYMER COMPOSITES. 31(3):491-496 (2010)journal articl