The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
Yuichi Sugai - One of the best experts on this subject based on the ideXlab platform.
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Heat Transfer and Phase Change in Deep CO2 Injector for CO2 Geological Storage
Two Phase Flow Phase Change and Numerical Modeling, 2011Co-Authors: Kyuro Sasaki, Yuichi SugaiAbstract:CO2 capture and storage (CCS) is expected to reduce CO2 emissions into the atmosphere. Various underground reservoirs and layers exist where CO2 may be stored such as aquifers, depleted oil and gas reservoirs as well as unmined coal seams. Coal seams are feasible for CCS because coal can adsorb CO2 gas with roughly twice volume compared with CH4 gas originaly stored (Yee et al., 1993). However, the coal matrix is swelling with adsorbing CO2 and its permeability is reduced. Supercritical CO2 has a higher injection rate of CO2 into coal seams than liquid CO2 because its viscosity is 40% lower than the liquid CO2 (see Harpalani and Chen, 1993). The Japanese consortium carried out the test project on Enhanced Coal Bed Methane Recovery by CO2 injection (CO2–ECBMR) at Yubari City, Hokkaido, Japan during 2004 to 2007 [Yamaguchi et al. (2007), Fujioka et al.(2010)]. The target coal seam at Yubari was located about 890 to 900 m below the surface (Yasunami et al., 2010). However, liquid CO2 was injected from the bottom holes because of heat loss along the deep injection tubing. The absolute pressure and temperature at the bottom hole was approximately 15.5MPa and 28°C. The regular tubing was replaced with thermally insulated tubing that included an argon gas layer but the temperature at the bottom was still lower than the critical temperature of CO2. This chapter provides a numerical model of heat transfer and calculation procedure for the prediction of CO2 temperature and pressure that includes a phase change (supercritical or liquid) by considering the heat loss from the injector to surrounding casing pipes and rock formation. Furthermore, this study provides numerical simulation results of the temperature distribution of the coal seam after the injection of CO2.
Judith L. Newman - One of the best experts on this subject based on the ideXlab platform.
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Developmental perspectives on embodiment and consciousness
2008Co-Authors: Willis F. Overton, Ulrich Mueller, Judith L. NewmanAbstract:Contents: Preface. W.F. Overton, Embodiment From a Relational Perspective. M. Johnson, The Meaning of the Body. G. Colombetti, E. Thompson, The Feeling Body: Towards an Enactive Approach to Emotion. J. Voneche, Action as the Solution to the Mind-Body Problem in Piaget's Theory. E. Thelen, Grounded in the World: Developmental Origins of the Embodied Mind. T.J. Csordas, Embodiment, Alterity, and the Theory of Religion. T.P. Racine, J.I.M. Carpendale, The Embodiment of Mental States. L.S. Liben, Embodiment and Children's Understanding of the Real and Represented World. H.H. Gao, P.D. Zelazo, Language and Development of Consciousness: Degrees of Disembodiment. E.K. Scholnick, P.H. Miller, Uncovering the Body in Conceptual Development: A Feminist Perspective. S.G. Fegley, M.B. Spencer, T.N. Goss, V. Harpalani, N. Charles, Colorism Embodied: Skin Tone and Psychosocial Well-Being in Adolescence. U. Muller, J.L. Newman, The Body in Action: Perspectives on Embodiment and Development.
La Tonya Noel - One of the best experts on this subject based on the ideXlab platform.
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sociocultural theories academic achievement and african american adolescents in a multicultural context a review of the cultural compatibility perspective
Journal of Negro Education, 2012Co-Authors: Arthur L Whaley, La Tonya NoelAbstract:Several theories suggest that African American culture facilitates academic achievement, but others suggest that identifying with Black culture contributes to the achievement gap by undermining the academic performance among youth. These opposing perspectives are labeled "cultural compatibility theories" and "cultural incompatibility theories," respectively. A previous review of the cultural incompatibility perspective reveals limited support for those theories. The current review of the literature complements the previous review with substantial support for the cultural compatibility perspective. Implications for theory, research, and practice addressing the racial gap in achievement by considering the cultural underpinnings of academic behavior in African American youth are discussed. Keywords: adolescence, African American, achievement gap, multicultural context, racial disparities, sociocultural theories There is substantial evidence of differential patterns of achievement between Black and White students in our nation's educational system - commonly referred to as the "achievement gap." African American students tend to underperform in terms of lower grade point averages (GPA) and weaker aptitude test scores than White students. The 2007 National Assessment of Educational Progress (NAEP) revealed higher rates of school readiness for White children than African American students (Aud, Fox, & KewalRamani, 2010). Research has also demonstrated that African American students have higher dropout rates from high school (National Center for Education Statistics, 2002; Osborne & Walker, 2006). Even when African American students graduate from high school, according to Aud and colleagues (2010), they are less likely to enroll in and graduate from college. The long-lasting effects that academic achievement gaps between African American and White students have had in the larger society warrant continued theoretical and empirical analysis of the issue. Academic achievement is positively correlated with educational attainment (Hansen, Heckman, & Mullen, 2004) and educational attainment has a positive correlation with one's socioeconomic status (Pallas, 2000). Therefore, the continued existence of academic achievement gaps will contribute to the persistence of racial inequality in other areas of life. Finally, empirical tests of theories to account for the Black-White academic gap have been growing, and increasing the knowledge base could have implications for policy and public opinion about reducing racial disparities in educational outcomes. Of particular interest and in need of further analysis are sociocultural theories about the Black-White achievement gap in academic performance. These theories can be divided into competing explanations: some theorists suggest African American culture facilitates academic achievement (Oyserman, Gant, & Ager, 1995; Spencer, 1999; Whaley, 2003); whereas others suggest that identifying with Black culture contributes to the achievement gap by undermining academic performance (Fordham & Ogbu, 1986; Steele, 1997). The authors have categorized the conceptual frameworks reflecting these opposing perspectives as "cultural compatibility theories" and "cultural incompatibility theories," respectively. In this article, the cultural compatibility perspective will be defined and evaluated by a review of the evidence in support of the following three major theories: (a) socially contextualized model of African American identity (Oyserman, Gant, & Ager, 1995); (b) phenomenological variant of ecological systems theory (Spencer, 1999; Spencer, Dupree, & Hartman, 1997; Spencer, Noll, Stoltzfus, & Harpalani, 2001); and (c) the cultural-cognitive model of African American identity (Whaley, 2003, Whaley & McQueen, 2010). This review will include studies that assess the role of culture in a broader multicultural context. Finally, implications drawn from the empirical evidence for the Black-White achievement gap will be discussed. …
Brian L. Wright - One of the best experts on this subject based on the ideXlab platform.
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Racial-Ethnic Identity, Academic Achievement, and African American Males: A Review of Literature.
Journal of Negro Education, 2009Co-Authors: Brian L. WrightAbstract:This article discusses broadly, the literature on racial-ethnic identity (REI) and its role as a factor to promote academic success in young African American adolescents, in particular males. The review also defines, describes, and interprets styles of self-presentation that reflect aspects of REI among African American males in and outside of school toward the development of a healthy REI. The overall objective of this review of literature is to change the often negative ways in which society thinks and talks about African American students, especially males, in terms of their REI and their academic achievement toward the development of a healthy REI. INTRODUCTION In trying to explain the educational experiences of young African American men, many researchers have adhered to deficit-oriented explanations (Bereiter & Engleman, 1966; Deutsch, 1963; Hess & Shipman, 1965). More often than not these explanations have focused only on deficiencies among African American families and their children, rather than on their strengths (e.g., Garbarino, 1995; Kozol, 1991; Perry, Steele, & Hilliard, 2003; Slaughter-Defoe, Nakagawa, Takaniski, & Johnson, 1990; Spencer, Harpalani, Fegley, Dell'Angelo, & Seaton, 2002). In addition, some social scientists (e.g., Hernstein & Murray, 1994; Jensen, 1969) have pointed to genetics, dysfunctional families, lazy and unmotivated students, and the "culture of poverty" in inner-city neighborhoods to explain the academic underachievement of African American students, particularly males. Unconvinced by earlier explanations as to why African American students persistently underachieve, Steele (1999) argued that a "stereotype threat" contributes to their school failure. Other scholars, including sociolinguists (e.g., Au, 1980; Heath, 1983), and educational researchers (e.g., Irvine, 2003; Lee, 2004), have focused on the cultural mismatch that contributes to the failure of African American students. In response, researchers of multicultural education (e.g., Banks, 2004; Gay 2004; Grant 2003), and curriculum theorists (e.g., Apple, 1990; Popkewite, 1998), have focused primarily on the nature of the curriculum and the school as contributing to the persistent academic underachievement among non- White students. These researchers asserted that although some improvements in the curriculum relative to gender and minority issues show marked improvements, the formal curriculum or the Official curriculum' as it is sometimes referred to, is in reality, still wanting. For example, it is seen as fragmented, racist, and also sexist in favor of White middle-class Western students (Banks, 1996). For these reasons, when the official curriculum goes unchallenged, it can, and often does, contribute to the development of unfavorable attitudes and even disintegration on the part of nonWhite students with respect to their educational experience (see Sleeter, 2001). This is especially true of African American males who often perceive the curriculum as a negative critique of their racial-ethnic group in terms of their dignity and worth (Polite & David, 1999; Swanson, Cunningham & Spencer, 2005). In response to their perception of the formal curriculum, it is believed that some young African American male students may demonstrate an "oppositional stance" toward their academic subjects and school. However, this is not because some may lack the ability to actually do the work or feel that education is unimportant to their lives, but rather because of the negative ways in which they are categorically presented in the curriculum. Therefore, rather than handle low academic expectations from teachers, as well as emotional and psychological assaults on their racial-ethnic identity (REI), as a result of racism and discrimination, many of these young men view the choice to leave school before graduation as their only option (see Ferguson, 2001). Finally, ignored in all of these explanations are those socially and academically successful African American male adolescents who do manage to achieve at high levels while also asserting a healthy REI in the context of school, despite the factors often cited in the literature (e. …
Satya Harpalani - One of the best experts on this subject based on the ideXlab platform.
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Laboratory measurement of stress-dependent coal permeability using pulse-decay technique and flow modeling with gas depletion
Fuel, 2016Co-Authors: Ruimin Feng, Satya Harpalani, Rohit PandeyAbstract:Abstract A laboratory-scale coal permeability measurement study using the pressure pulse decay method was carried out to establish the permeability variation trend impacted by the combined effects of effective stresses and coal matrix shrinkage associated with gas depletion under uniaxial strain condition for San Juan basin coal. The experimental results showed that increased effective horizontal stress negatively impacts permeability enhancement. Furthermore, effective horizontal stress dominates the permeability variation. Finally, the rate of permeability increase accelerates dramatically at low pressures as a result of decrease in effective horizontal stress due to the matrix shrinkage effect. The established pressure-dependent-permeability (PdK) was compared with modeled results using two models, Harpalani and Chen and Shi and Durucan, both based on variations in effective horizontal stress. The match with the results obtained using the Harpalani and Chen model was perfect when appropriate initial cleat porosity and matrix shrinkage strain parameters were used. However, given the analytical conditions presented, the agreement between experimental and modeled results using the Shi and Durucan model was poor. After reviewing the fundamental principles behind model development, a modification was made, based on geo-mechanical principles. The measured permeability variation matched well with the results predicted by the modified model when appropriate cleat compressibility values were used. Basically, the revised model increases the effect of matrix shrinkage on permeability changes with continued depletion. The modeled results showed a permeability trend consistent with the experimental result although the permeability of coal was overestimated at low pressures.
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Permeability prediction of coalbed methane reservoirs during primary depletion
International Journal of Coal Geology, 2013Co-Authors: Satya HarpalaniAbstract:Abstract Permeability increase in coalbed methane (CBM) reservoirs during primary depletion, particularly in the San Juan Basin, is a well accepted phenomenon. It is complex since it is influenced by stress conditions and coal matrix shrinkage associated with gas desorption. Understanding the variations in coal permeability is critical in order to reliably project future gas production, or consider other gas migration issues in the reservoir. Since sorption-induced strain plays a critical role in changing the permeability, typically observed, the theoretical strain model should be incorporated into the permeability prediction models. An effort is made in this paper to couple the recently developed Liu and Harpalani sorption-induced strain model with various permeability models. The model first calculates the theoretical coal matrix shrinkage strain and, using the calculated strain, various commonly used permeability models are applied to two sets of field data. The results of the coupled models show that the agreement between the predicted permeability and that observed in the field is very good. The merit of the coupled models is that it can theoretically predict the permeability with less experimental work, making it a more time efficient and economical technique compared to models used in the past.
