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Alternative Concept (alternative + concept)
Selected AbstractsAlternative concept for SOFC with direct internal reforming operation: Benefits from inserting catalyst rodAICHE JOURNAL, Issue 6 2010Pannipha Dokamaingam Abstract Mathematical models of direct internal reforming solid oxide fuel cell (DIR-SOFC) fueled by methane are developed using COMSOL® software. The benefits of inserting Ni-catalyst rod in the middle of tubular-SOFC are simulated and compared to conventional DIR-SOFC. It reveals that DIR-SOFC with inserted catalyst provides smoother temperature gradient along the system and gains higher power density and electrochemical efficiency with less carbon deposition. Sensitivity analyses are performed. By increasing inlet fuel flow rate, the temperature gradient and power density improve, but less electrical efficiency with higher carbon deposition is predicted. The feed with low inlet steam/carbon ratio enhances good system performances but also results in high potential for carbon formation; this gains great benefit of DIR-SOFC with inserted catalyst because the rate of carbon deposition is remarkably low. Compared between counter- and co-flow patterns, the latter provides smoother temperature distribution with higher efficiency; thus, it is the better option for practical applications. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Learning from Difference: Considerations for Schools as CommunitiesCURRICULUM INQUIRY, Issue 3 2000Carolyn M. Shields In today's highly complex and heterogeneous public schools, the current notion of schools as homogeneous communities with shared beliefs, norms, and alues is inadequate. Drawing on Barth's (1990) question of how to use ifference as a resource, I take up ideas from feminism, multiculturalism, and inclusive education to consider the development of community in schools. I argue that despite the valuable contributions of these theoretical perspectives, each lso includes the potential for increased fragmentation and polarization. As we consider how to use differences as a foundation for community, it is important ot to reify any particular perspective, thus marginalizing others and erecting new barriers. Explicitly embracing the need to identify and respect difference, being open to new ideas without taking an exclusionary position, and committing to ongoing participation in dialogical processes may help schools to develop as more authentic communities of difference. Among the dominant issues identified in today's climate of turbulent educational reform are concerns about how to restructure schools to ensure equality of student opportunity and excellence of instruction (Elmore, 1990; Lieberman, 1992; Murphy, 1991). Many proposals include modifying present leadership and governance structures, overcoming the hegemony of existing power bases, developing mechanisms for accountability, enhancing professionalism, and co-ordinating community resources. One of the suggestions frequently made to address these issues is to change from a focus on schools as organizations to a recognition of schools as communities (Barth, 1990; Fullan, 1993; Lupart & Webber, 1996; Senge, 1990). However, despite the widespread use of the metaphor of community as an alternative to the generally accepted concept of schools as rational or functional organizations, there seems to be little clarity about the concept of community, what it might look like, how it might be implemented, or what policies might sustain it. Indeed, theories about schools as communities have often drawn from Tönnies (1887/1971) concept of gemeinschaft,a concept which perhaps evokes a more homogeneous and romanticized view of the past than one which could be helpful for improving education in today's dynamic, complex, and heterogeneous context (Beck & Kratzer, 1994; Sergiovanni, 1994a). More recently, several writers (Fine et al., 1997; Furman, 1998; Shields & Seltzer, 1997) have advanced the notion of communities of otherness or difference. These authors have suggested that rather than thinking of schools as communities that exist because of a common affiliation to an established school ethos or tradition, it might be more helpful to explore an alternative concept. A school community founded on difference would be one in which the common centre would not be taken as a given but would be co-constructed from the negotiation of disparate beliefs and values as participants learn to respect, and to listen to, each other. In this concept, bonds among members are not assumed, but forged, and boundaries are not imposed but negotiated. Over the past eight years, as I have visited and worked with a large number of schools trying earnestly to address the needs of their diverse student bodies, I have become increasingly aware of the limitations of the concept of community used in the gemeinschaft sense with its emphasis on shared values, norms, and beliefs, and have begun to reflect on the question framed by Barth (1990): ,How can we make conscious, deliberate use of differences in social class, gender, age, ability, race, and interest as resources for learning?' (p. 514). In this article, I consider how learning from three of these areas of difference: gender, race, and ability, may help us to a better understanding of educational community. This article begins with some illustrations and examples from practice, moves to consider how some theoretical perspectives may illuminate them, and concludes with reflections on how the implications of the combined reflections on practice and theory might actually help to reconceptualize and to improve practice. While it draws heavily on questions and impressions which have arisen out of much of my fieldwork, it is not intended to be an empirical paper, but a conceptual one,one which promotes reflection and discussion on the concept of schools as communities of difference. The examples of life in schools taken from longitudinal research studies in which I have been involved demonstrate several common ways in which difference is dealt with in today's schools and some of the problems inherent in these approaches. Some ideas drawn from alternative perspectives then begin to address Barth's question of how to make deliberate use of diversity as a way of thinking about community. Taken together, I hope that these ideas will be helpful in creating what I have elsewhere called ,schools as communities of difference' (Shields & Seltzer, 1997). [source] The concept of disease: ethical challenges and relevance to dentistry and dental educationEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 1 2001Bjørn M. Hofmann Modern medicine and dentistry face fundamental ethical challenges. To treat or not to treat, that is the question! Can these challenges be met with a rigorous and consistent concept of disease? This is the key question of this article and the ensuing debate is of fundamental importance in the teaching of ethics to medical and dental students. The investigation of traditional concepts of disease reveals that they are flawed and do not withstand ethical challenges. An alternative concept of human ailment is elaborated on, based on the triad disease, illness and sickness. This model is applied to representative cases in medicine in general and dentistry in particular. It is argued that the concepts of disease, illness and sickness represent a framework for analysing and coping with inherent ethical challenges. This reveals that medicine and dentistry are concerned both with biological explanations and with questions of the virtuous life, i.e., both with science and with ethics. These considerations pose challenges for the health professions as a whole, but particularly for those concerned with educating the practitioners of the future. [source] Social Citizenship in the European Union: Nested MembershipJCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 1 2001Thomas Faist The ,European social dimension' offers a strategic entry point for analysing the development of citizenship in the European Union (EU). The first part of this contribution discusses the functions of social citizenship in this emerging multi-level governance network. Second, the analysis deals with two prominent and stylized paradigms that have sought to grasp the new multiple-level quality of social citizenship in the EU: residual and post-national concepts of membership in liberal democracies and advanced welfare states. Although each of these approaches captures selected elements of social citizenship, they are unable to deal with rights and duties in multiple governance levels in a satisfactory way. Therefore, the discussion moves to an alternative concept,nested citizenship. This means that European citizenship is nested in various sites: regional, state and supra-state forms of citizenship function in complementary ways,while the associated norms, rules and institutions are subject to constant revision and further development on all governance levels. Third, the analysis shows that the concept of nested citizenship can help to overcome the fruitless dichotomy of Euro-optimism and Euro-pessimism concerning social policy and citizenship. This discussion suggests a conception of European social citizenship as a common project, evolving towards common present- and future-oriented understandings of substantial rights and democratic principles in the EU. [source] A REVIEW OF GEOLOGICAL DATA THAT CONFLICT WITH THE PARADIGM OF CATAGENIC GENERATION AND MIGRATION OF OILJOURNAL OF PETROLEUM GEOLOGY, Issue 3 2005H. Hugh Wilson The majority of petroleum geologists today agree that the complex problems that surround the origin, generation, migration and accumulation of hydrocarbons can be resolved by accepting the geochemical conclusion that the process originates by catagenic generation in deeply-buried organically-rich source rocks. These limited source rock intervals are believed to expel hydrocarbons when they reach organic maturity in oil kitchens. The expelled oil and gas then follow migration pathways to traps at shallower levels. However, there are major geological obstacles that cast doubt upon this interpretation. The restriction of the source rock to a few organically rich levels in a basin forces the conclusion that the basin plumbing system is leaky and allows secondary horizontal and vertical migration through great thicknesses of consolidated sedimentary rocks in which there are numerous permeability barriers that are known to effectively prevent hydrocarbon escape from traps. The sourcing of lenticular traps points to the enclosing impermeable envelope as the logical origin of the trapped hydrocarbons. The lynch-pin of the catagenic theory of hydrocarbon origin is the expulsion mechanism from deeply-buried consolidated source rock under high confining pressures. This mechanism is not understood and is termed an "enigma". Assuming that expulsion does occur, the pathways taken by the hydrocarbons to waiting traps can be ascertained by computer modelling of the basin. However, subsurface and field geological support for purported migration pathways has yet to be provided. Many oilfield studies have shown that oil and gas are preferentially trapped in synchronous highs that were formed during, or very shortly after, the deposition of the charged reservoir. An unresolved problem is how catagenically generated hydrocarbons, expelled during a long-drawn-out maturation period, can have filled synchronous highs but have avoided later traps along the assumed migration pathways. From many oilfield studies, it has also been shown that the presence of hydrocarbons inhibits diagenesis and compaction of the reservoir rock. This "Füchtbauer effect" points to not only the early charging of clastic and carbonate reservoirs, but also to the development of permeability barriers below the early-formed accumulations. These barriers would prevent later hydrocarbon additions during the supposed extended period of expulsion from an oil kitchen. Early-formed traps that have been sealed diagenetically will retain their charge even if the trap is opened by later structural tilting. Diagenetic traps have been discovered in clastic and carbonate provinces but their recognition as viable exploration targets is discouraged by present-day assumptions of late hydrocarbon generation and a leaky basin plumbing system. Because there are so many geological realities that cast doubt upon the assumptions that devolve from the paradigm of catagenic generation, the alternative concept of early biogenic generation and accumulation of immature oil, with in-reservoir cracking during burial, is again worthy of serious consideration. This concept envisages hydrocarbon generation by bacterial activity in many anoxic environments and the charging of synchronous highs from adjacent sources. The resolution of the fundamental problem of hydrocarbon generation and accumulation, which is critical to exploration strategies, should be sought in the light of a thorough knowledge of the geologic factors involved, rather than by computer modelling which may be guided by questionable geochemical assumptions. [source] Managing the risks of physical intervention: developing a more inclusive approachJOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 4 2010L. HOLLINS bsc physiotherapy Accessible summary ,,It is imperative that the use of physical interventions be reduced. However, when they are used the safety of recipients must be maximized. ,,A focus on the ,prone restraint position' has led to a narrowed understanding of the risks associated with the application of force during restraints. ,,The ,transitional stabilizing position' offers a platform upon which to consider the broader risks arising during restraints. ,,Training staff to manage such situational risks, using a variation on the existing ABC safety check could be instrumental in reducing the likelihood of adverse outcomes associated with restraints. Abstract Since psychiatry evolved as a professional discipline, mental healthcare professionals have had to, as a last resort, physically intervene to manage physically aggressive patients. In the United Kingdom, physical intervention techniques migrated from the prison service in the mid 1980s where there was extensive use of two particularly controversial practices; ,pain compliance' and the ,prone restraint position'. This paper examines how the classification of the ,prone restraint position' has led to a narrowed focus on one technique and a resultant misunderstanding around the wider risks associated with the applying force and managing restraints. The paper goes on to propose the ,transitional stabilizing position' (TSP) as an alternative concept and puts forward a dynamic risk assessment model. It explores how a shift in staff training away from developing pure competence in the performance of tightly specified techniques to managing the patient in TSPs could conceivably reduce the relatively low risk of death or serious injury associated with the application of restraint techniques to an even lower level. [source] Liver transplantation for subacute hepatocellular failure due to massive steatohepatitis after bariatric surgeryLIVER TRANSPLANTATION, Issue 6 2008Luiz Augusto Carneiro D'Albuquerque New therapeutic options for obesity include restrictive bowel surgery and surgery that promotes malabsorption, such as the Fobi-Capella (gastric bypass) and Scopinaro (biliopancreatic diversion) techniques. Complications associated with these procedures, such as hepatocellular failure, have been observed with increasing frequency. Reported here are 3 patients who, 7 to 24 months after bariatric surgery, developed hepatocellular failure, for which liver transplantation was considered to be indicated. Liver transplantation was undertaken in 2 of the patients; the third patient died while waiting for this procedure. We discuss the possible causes of this uncommon and poorly understood complication of surgery for obesity. One possibility is that it might arise as a result of progression of steatohepatitis. An alternative concept is that this complication may be secondary to rapid, massive loss of body weight. Liver Transpl 14:881,885, 2008. © 2008. [source] Non-Covalent Polyvalent Ligands by Self-Assembly of Small Glycodendrimers: A Novel Concept for the Inhibition of Polyvalent Carbohydrate,Protein Interactions In Vitro and In VivoCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2006Gebhard Thoma Dr. Abstract Polyvalent carbohydrate,protein interactions occur frequently in biology, particularly in recognition events on cellular membranes. Collectively, they can be much stronger than corresponding monovalent interactions, rendering it difficult to control them with individual small molecules. Artificial macromolecules have been used as polyvalent ligands to inhibit polyvalent processes; however, both reproducible synthesis and appropriate characterization of such complex entities is demanding. Herein, we present an alternative concept avoiding conventional macromolecules. Small glycodendrimers which fulfill single molecule entity criteria self-assemble to form non-covalent nanoparticles. These particles,not the individual molecules,function as polyvalent ligands, efficiently inhibiting polyvalent processes both in vitro and in vivo. The synthesis and characterization of these glycodendrimers is described in detail. Furthermore, we report on the characterization of the non-covalent nanoparticles formed and on their biological evaluation. [source] Uremic Toxins: Removal with Different TherapiesHEMODIALYSIS INTERNATIONAL, Issue 2 2003Raymond C. Vanholder A convenient way to classify uremic solutes is to subdivide them according to the physicochemical characteristics influencing their dialytic removal into small water-soluble compounds (<500 Da), protein-bound compounds, and middle molecules (>500 Da). The prototype of small water-soluble solutes remains urea although the proof of its toxicity is scanty. Only a few other water-soluble compounds exert toxicity (e.g., the guanidines, the purines), but most of these are characterized by an intra-dialytic behavior, which is different from that of urea. In addition, the protein-bound compounds and the middle molecules behave in a different way from urea, due to their protein binding and their molecular weights, respectively. Because of these specific removal patterns, it is suggested that new approaches of influencing uremic solute concentration should be explored, such as specific adsorptive systems, alternative dialytic timeframes, removal by intestinal adsorption, modification of toxin, or general metabolism by drug administration. Middle molecule removal has been improved by the introduction of large pore, high-flux membranes, but this approach seems to have come close to its maximal removal capacity, whereas multicompartmental behavior might become an additional factor hampering attempts to decrease toxin concentration. Hence, further enhancement of uremic toxin removal should be pursued by the introduction of alternative concepts of elimination. [source] Are hybridogenetic complexes structured by habitat in water frogs?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2005S. PLENET Abstract The success and the evolutionary fate of hybridogenetic lineages are explained by both a generalistic heterosis hypothesis and an alternative hypothesis, the habitat segregation hypothesis. Because such hypotheses have rarely been tested at the level of whole habitats, our aim was to compare performances of two taxa within a hybridogenetic complex across diverse natural habitats. We took advantage of the waterfrog hybridogenetic complex (Rana esculenta and R. lessonae) by rearing tadpoles in natural contrasted habitats by means of enclosure experiments. We also monitored the frequency of each taxon in the waterfrog assemblages that naturally breed in the studied ponds. The hybridogenenetic taxon showed no evidence of broader tolerance as growth, development and physiology strongly varied in response to environmental heterogeneity. Our study reveals a differential success of the hybridogenetic taxon and its sexual host among environments. Moreover, hybridogenetic taxa rarely dominated the sexual species in natural assemblages. Consequently, our results show that the generalistic model does not explain the success of hybridogenetic lineages, but rather support the habitat segregation, among other alternative concepts. [source] Factors that prevent learning in electrochemistryJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 2 2007Hans-Jürgen Schmidt Electrochemistry plays an important role in curricula, textbooks, and in everyday life. The purpose of the present study was to identify and understand secondary-school students' problems in learning electrochemistry at an introductory chemistry level. The investigation covered four areas: (a) electrolytes, (b) transport of electric charges in electrolyte solutions, (c) the anode and the cathode, and (d) the minus and plus poles. Written tests were given to high-school students in five cycles. The population from which random samples were drawn totalled 15,700 subjects. Students were asked to select the correct answers and to justify their choices. It was found that students based their reasoning on four alternative concepts: (a) During electrolysis, the electric current produces ions; (b) electrons migrate through the solution from one electrode to the other; (c) the cathode is always the minus pole, the anode the plus pole; and (d) the plus and minus poles carry charges. The results suggest a teaching strategy in which students first experience and learn about electrochemistry concepts. In the second step, appropriate concept terms are added, and students then are confronted with the alternative concepts described in this article. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 258,283, 2007 [source] | ||||||||||||||||