Literatura académica sobre el tema "Lack of fluidity"
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Artículos de revistas sobre el tema "Lack of fluidity"
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Vareesangthip, K., R. Wilkinson y T. H. Thomas. "Lack of function of an N-ethylmaleimide-sensitive thiol protein in erythrocyte membrane of autosomal dominant polycystic kidney disease." Journal of the American Society of Nephrology 9, n.º 1 (enero de 1998): 1–8. http://dx.doi.org/10.1681/asn.v911.
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The polycystic kidney disease 1 (PKD1) gene product polycystin has been predicted to be an integral membrane protein involved in cell-cell and cell-matrix interactions. The erythrocyte membrane fluidity in autosomal dominant polycystic kidney disease (ADPKD) patients is increased, and this may be due to a membrane cytoskeletal abnormality. The abnormal erythrocyte sodium-lithium countertransport kinetics in-ADPKD are related to an altered thiol protein in the cytoskeleton. The possibility that a similar thiol protein abnormality causes the increased erythrocyte membrane fluidity in ADPKD was investigated. The membrane fluidity of intact erythrocytes from 12 ADPKD patients and 12 healthy control subjects was assessed from the fluorescence anisotropies of 1,6-diphenyl-1,3,5-hexatriene (DPH) and trimethylammonium-diphenyl-hexatriene (TMA-DPH). The effect on membrane fluidity of N-ethylmaleimide (NEM), cytochalasin D, heating at 48 degrees C for 20 min, or more specifically, liposomes containing antibodies to actin or ankyrin, was determined. In erythrocytes from healthy control subjects, the fluorescence anisotropy of DPH (mean +/- SEM: 0.223 +/- 0.001) was decreased after treatment with NEM (0.200 +/- 0.003, P < 0.001), cytochalasin D (0.206 +/- 0.006, P < 0.001), heating (0.199 +/- 0.002, P < 0.001), and antibodies to actin (0.194 +/- 0.002, P < 0.001) or ankyrin (0.196 +/- 0.002, P < 0.001). The TMA-DPH anisotropy (0.279 +/- 0.001) was also decreased after treatment with NEM (0.264 +/- 0.001, P < 0.001), cytochalasin D (0.264 +/- 0.001, P < 0.001), heating (0.265 +/- 0.001, P < 0.001), and antibodies to actin (0.262 +/- 0.002, P < 0.001) or ankyrin (0.262 +/- 0.002, P < 0.001). NEM had no additional effect on the other treatments, suggesting that its target thiol protein was associated with the cytoskeleton. In untreated erythrocytes from ADPKD patients, fluorescence anisotropies of both DPH and TMA-DPH were reduced, and none of the treatments altered the anisotropy of either DPH or TMA-DPH. In ADPKD, a cytoskeletal thiol protein is abnormal and possibly explains abnormal lipid bilayer properties and transport protein function in erythrocytes in this disease.
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Braungardt, Hannah y Vineet K. Singh. "Impact of Deficiencies in Branched-Chain Fatty Acids and Staphyloxanthin inStaphylococcus aureus". BioMed Research International 2019 (22 de enero de 2019): 1–8. http://dx.doi.org/10.1155/2019/2603435.
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Staphylococcus aureusis a well-known human pathogen with the ability to cause mild superficial skin infections to serious deep-tissue infections, such as osteomyelitis, pneumonia, and infective endocarditis. A key toS. aureusinfections and its pathogenicity is its ability to survive in adverse environments, especially at lower temperatures, by regulation of its cell membrane. Branched-chain fatty acids (BCFAs) and staphyloxanthin have been shown to regulate membrane fluidity and staphylococcal virulence. This study was conducted with the hypothesis that the simultaneous lack of BCFAs and staphyloxanthin will have a far greater implication on environmental survival and virulence ofS. aureus. Lack of a functional branched-chainα-keto acid dehydrogenase (BKD) enzyme because of a mutation in thelpdAgene led to a decrease in the production of BCFAs, membrane fluidity, slower growth, and poorin vivosurvival ofS. aureus. A mutation in thecrtMgene eliminated the production of staphyloxanthin but it did not affect membrane BCFA levels, fluidity, growth, orin vivosurvival. AcrtM:lpdAdouble mutant showed much slower growth and attenuation compared to individual mutants. The results of this study suggest that simultaneous targeting of the BCFA and staphyloxanthin biosynthetic pathways can be a strategy to controlS. aureusinfections.
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Hassan, Shatha Abbas y Noor Ali Aljorani. "The Effect of Information Technology on Fluidity of Contemporary Architectural Space". Wasit Journal of Engineering Sciences 7, n.º 1 (15 de abril de 2019): 62–72. http://dx.doi.org/10.31185/ejuow.vol7.iss1.115.
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The increasing importance of the information revolution and terms such as ‘speed’, ‘disorientation’, and ‘changing the concept of distance’, has provided us with tools that had not been previously available. Technological developments are moving toward Fluidity, which was previously unknown and cannot be understood through modern tools. With acceleration of the rhythm in the age we live in and the clarity of the role of information technology in our lives, as also the ease of access to information, has helped us to overcome many difficulties. Technology in all its forms has had a clear impact on all areas of daily life, and it has a clear impact on human thought in general, and the architectural space in particular, where the architecture moves from narrow spaces and is limited to new spaces known as the ‘breadth’, and forms of unlimited and stability to spaces characterized with fluidity. The research problem (the lack of clarity of knowledge about the impact of vast information flow associated with the technology of the age in the occurrence of liquidity in contemporary architectural space) is presented here. The research aims at defining fluidity and clarifying the effect of information technology on the changing characteristics of architectural space from solidity to fluidity. The research follows the analytical approach in tracking the concept of fluidity in physics and sociology to define this concept and then to explain the effect of Information Technology (IT) to achieve the fluidity of contemporary architectural space, leading to an analysis of the Skidmore, Owings and Merrill (SOM) architectural model. The research concludes that information technology achieves fluidity through various tools (communication systems, computers, automation, and artificial intelligence). It has changed the characteristics of contemporary architectural space and made it behave like an organism, through using smart material.
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Bekenova, Assel. "The Effect of Electoral Systems on Fluid Party System in sub-Saharan Africa". Otoritas : Jurnal Ilmu Pemerintahan 12, n.º 2 (31 de octubre de 2022): 95–107. http://dx.doi.org/10.26618/ojip.v12i2.7723.
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The article, based on a literature review, examines the impact of electoral systems on the fluidity party system in sub-Saharan Africa. Most authors identify institutional and social factors influencing the change in party systems. At the same time, they use the indices Laakso and Taagepera and Rae to operationalize variable parties. However, there is a lack of research in the literature on electoral systems regarding its impact on stability or change of interparty competition patterns. This is due to, firstly, the relative novelty of the recently developed index of fluidity, and secondly, the desire of scholars to use already widely tested, established measures of measurement. We believe that, in contrast to previous studies, where the unit of analysis is the party and not the party system. The Index of Fluidity will allow us to predict how majoritarian or proportional systems and WGI scores will affect the structure or fluidity of party systems in 49 sub-Saharan African countries. The results of study indicate that the changes taking place in electoral systems have significantly affected the fluidity of party systems. The results of the study indicate that measures of WGI and ethnicity negatively affected fluidity of party systems in 49 sub-Saharan African countries. This suggests that the more unstable the party system, the more ineffective the government becomes. Whereas the results of the main hypothesis indicate a statistically significant effect of changing electoral systems on the fluidity of party systems. In other words, the more often political reforms are carried out in the electoral sphere, the higher the indicators of instability of party system, which, according to the typology of party system of Sartori, will change either radically from one-party to polarized pluralism or atomised party system or slightly from one-party to hegemonistic or predominant.
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Breen, Richard. "Education and intergenerational social mobility in the US and four European countries". Oxford Review of Economic Policy 35, n.º 3 (2019): 445–66. http://dx.doi.org/10.1093/oxrep/grz013.
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Abstract I draw on the findings of a recently completed comparative research project to address the question: how did intergenerational social mobility change over cohorts of men and women born in the first two-thirds of the twentieth century, and what role, if any, did education play in this? The countries studied are the US, France, Germany, the Netherlands, and Sweden. Notwithstanding the differences between them, by and large they present the same picture. Rates of upward mobility increased among cohorts born in the second quarter of the century and then declined among those born later. Among earlier born cohorts, social fluidity increased (that is, the association between the class a person was born into and the class he or she came to occupy as an adult declined) and then remained unchanged for those born after mid-century. The association between class origins and educational attainment followed much the same trend as social fluidity. This suggests that growing equalization in education may have contributed to the increase in social fluidity. In our analyses we find that this is so, but educational expansion also led to greater fluidity in some countries. There is also a strong link between upward mobility and social fluidity. Upward mobility was mostly driven by the expansion of higher-level white-collar jobs, especially in the 30 years after the end of the Second World War. This facilitated social fluidity because people from working class and farming origins could move into the service or salariat classes without reducing the rate at which children born into those classes could remain there. Educational expansion, educational equalization, and rapid structural change in the economies of the US and Europe all contributed to greater social fluidity among people born in the second quarter of the twentieth century. For people born after mid-century, rates of downward mobility have increased: however, despite the lack of further educational equalization and less pronounced structural change, social fluidity has remained unchanged.
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Basu, Anupam. "“What do you lack? What is’t you buy?”: Commodity and Community in Bartholomew Fair". Ben Jonson Journal 29, n.º 2 (noviembre de 2022): 141–69. http://dx.doi.org/10.3366/bjj.2022.0337.
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Jonson’s Bartholomew Fair uses the comic representation of criminality to comment on the urban culture of commodities. The variety of goods bought, sold, circulated, stolen and exchanged in the fair become a trope for the fluidity and malleability of the commodity form, not tied to particular material histories or uses, but part of an emerging fluid ideological space of the market. Against the decay of traditional notions of community, the play proposes a new and radical model of temporary, tactical, mobile and fluid alliances – a community of rogues based on the trope of the commodity form and the economic contract.
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Luo, Tao, Yunzhu Ma, Shuwei Yao, Juan Wang y Wensheng Liu. "Experimental and Molecular Dynamics Simulation Study on Sol–Gel Conversion Process of Aluminum Carboxylate System". Materials 15, n.º 7 (6 de abril de 2022): 2704. http://dx.doi.org/10.3390/ma15072704.
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Due to the lack of relevant in situ characterization techniques, the investigation of aluminum sol–gel progress is lacking. In this study, combined with molecular dynamics simulation and conventional experimental methods, the microstructures, rheological properties, and gelation process of the carboxylic aluminum sol system were studied. The experimental results showed that, with the increase in solid content, the microstructure of the colloid developed from a loose and porous framework to a homogeneous and compact structure. The viscosity of aluminum sol decreased significantly with the increase in temperature, and a temperature above 318 k was more conducive to improving the fluidity. The simulation results show that the increase in free volume and the connectivity of pores in colloidal framework structure were the key factors to improve fluidity. In addition, free water molecules had a higher migration rate, which could assist the rotation and rearrangement of macromolecular chains and also played an essential role in improving fluidity. The Molecular dynamics simulation (MD) results were consistent with experimental results and broaden the scope of experimental research, providing necessary theoretical guidance for enhancing the spinning properties of aluminum sol.
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Lampe, L., K. Wienhold, G. Meyer, F. Baisch, H. Maass, W. Hollmann y R. Rost. "Effects of simulated microgravity (HDT) on blood fluidity". Journal of Applied Physiology 73, n.º 4 (1 de octubre de 1992): 1366–69. http://dx.doi.org/10.1152/jappl.1992.73.4.1366.
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Exposures to microgravity and head-down tilt (HDT) produce similar changes in body fluid. This causes an increase in hematocrit that significantly affects hemorheological values. Lack of physical stimulation under bed rest conditions and the relative immobility of the crew during spaceflight also affects the blood fluidity. A group of six healthy male subjects participated as volunteers, and blood samples were collected 10 days before, on day 2 and day 9, and 2 days after the HDT phase. Blood rheology was quantified by plasma viscometry, red cell aggregability, and red cell deformability. A reduced red cell deformability, an indication of the diminished quality of the red blood cells, was measured under HDT conditions that finally led to the so-called “space flight anemia.” Enhanced red cell membrane fragility induced by diminished physical activity and an increase in hemoglobin concentration are responsible for this effect. Plasma viscosity is reduced as a result of diminished plasma proteins. However, despite the reduction in plasma proteins, including fibrinogen, alpha 2-macroglobulin, and immunoglobulin M, red cell aggregation was enhanced, principally because of the increase in hematocrit. Our results of hemorheological alterations under HDT conditions may help to elucidate the formerly documented hematologic changes during spaceflight.
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Visioli, Francesco y Andrea Poli. "Fatty Acids and Cardiovascular Risk. Evidence, Lack of Evidence, and Diligence". Nutrients 12, n.º 12 (9 de diciembre de 2020): 3782. http://dx.doi.org/10.3390/nu12123782.
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One of the most controversial areas of nutrition research relates to fats, particularly essential fatty acids, in the context of cardiovascular disease risk. A critical feature of dietary fatty acids is that they incorporate into the plasma membrane, modifying fluidity and key physiological functions. Importantly, they can reshape the bioavailability of eicosanoids and other lipid mediators, which direct cellular responses to external stimuli, such as inflammation and chronic stress conditions. This paper provides an overview of the most recent evidence, as well as historical controversies, linking fat consumption with human health and disease. We underscore current pitfalls in the area of fatty acid research and critically frame fatty acid intake in the larger context of diet and behavior. We conclude that fundamental research on fatty acids and lipids is appropriate in certain areas, but the rigor and reproducibility are lacking in others. The pros and cons are highlighted throughout the review, seeking to guide future research on the important area of nutrition, fat intake, and cardiovascular disease risk.
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Bilohubkina, Karyna, Olena Fedorenko, Ruslan Kryvobok y Artem Zakharov. "DEVELOPMENT OF TECHNOLOGICAL PARAMETERS FOR THE FORMATION OF FASTS BY THE SLIDING CASTING METHOD". Bulletin of the National Technical University "KhPI". Series: Innovation researches in students’ scientific work, n.º 2 (16 de diciembre de 2021): 15–21. http://dx.doi.org/10.20998/2220-4784.2021.02.03.
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The materials of the article consider the effectiveness of additives for stabilization and dilution of clay-free slippers. For theproduction of radio-transparent ceramic materials of Celsius-Willemite composition, the most efficient and energy-saving methodof production is the method of slip casting. According to the charge composition, this technology is complicated by the lack of claycomponents, which shows the need to use impurities to improve the rheology of such a slip. The main characteristics of aqueousceramic slippers are density, humidity, fluidity, viscosity, density factor, rate of mass accumulation. The slip must meet thefollowing requirements: be free from foam and gas inclusions, have satisfactory fluidity under low viscosity; be aggregativelystable (characterized by the absence of aggregation, coagulation and sedimentation of solid phase particles); have a high filteringcapacity to ensure fast and defect-free weight gain; to be chemically inert, to provide sufficient strength and low shrinkage of semifinished products, as well as the possibility of their easy release from the mold.
Tesis sobre el tema "Lack of fluidity"
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Wartel, Alexandra. "Des manques de fluidité d’un processus technique au développement des activités collectives transverses : pour un regard de l’ergonomie sur la performance. Le cas de la préparation des traitements en radiothérapie externe". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0210.
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La radiothérapie externe est un traitement contre le cancer qui met en jeu différents professionnels issus de divers métiers et travaillant dans le cadre d’un processus de production du soin. L’Institut de Radioprotection et de Sûreté Nucléaire (IRSN) et l’Autorité de Sûreté Nucléaire (ASN) ont fait le constat de « manques de fluidité » de ce processus, particulièrement pour les phases liées à la préparation des traitements. Ces manques de fluidité peuvent avoir des effets sur le travail (réalisé dans l’urgence) et sur la sécurité des soins. Ce constat constitue l’objet de la demande initiale pour ce travail de recherche en ergonomie. Notre objectif est de comprendre l’origine et les effets des « manques de fluidité » du processus technique, constatés par l’IRSN et (ASN). Nous cherchons à caractériser les discontinuités du processus technique pour identifier leurs éventuels effets sur le travail des professionnels et la sécurité des patients. Pour ce faire, nous caractérisons les discontinuités du processus technique de préparation à travers la compréhension de l’articulation des activités individuelles et collectives, en mobilisant deux approches intrinsèques l’activité humaine développées en ergonomie, le cours d’action (Theureau, 2004) et l’approche instrumentale (Rabardel, 1995). Deux modes d’organisation sont majoritaires en radiothérapie externe. L’un d’entre eux, le plus répandu, détermine la date de début de traitement en amont de la préparation des traitements. L’autre, prépare les dossiers au fil de leur ordre d’arrivée et détermine la date de début de traitement une fois le dossier prêt, c’est le « fil de l’eau ». Nous appréhendons les effets respectifs de ces deux modes d’organisation sur la dynamique de développement des activités collectives, sur d’éventuelles discontinuités et sur la sécurité des soins. Nous montrerons comment les activités collectives transverses sont garantes de la continuité de la prise en charge des patients, mais aussi de l’élaboration d’un traitement de qualité et garantissant la sécurité des patients. Pourtant, ces activités collectives transverses et surtout les articulations nécessaires à leur développement ne sont pas prises en compte dans le découpage séquentiel du processus technique prescrit. À partir de ces connaissances empiriques, nous ouvrons la réflexion sur des perspectives de conception en mettant en avant ce que les organisations devraient prendre en compte pour permettre et soutenir le développement des activités collectives transverses réelles, engagées dans la préparationExternal radiotherapy is a cancer treatment that involves several professionals from a variety of fields, working within the framework of a care production process. The Institute for Radiation Protection and Nulcear Safety (IRSN) and the Nuclear Safety Authority (ASN) have observed a "lack of fluidity" in this process, particularly in the treatment preparation phases. This lack of fluidity can have an impact on work (carried out in a hurry) and on the safety of care. This observation is the subject of the initial request for this ergonomic research project. Our aim is to understand the origin and effects of the "lack of fluidity" in the technical process, as observed by IRSN and ASN. We aim to characterize discontinuities in the technical process, in order to identify their possible effects on the work of professionals and on patient safety. To do this, we characterize discontinuities in the technical preparation process by understanding the articulation of individual and collective activities, using two intrinsic approaches of the human activity developed in ergonomics : the course of action (Theureau, 2004) and the instrumental approach (Rabardel, 1995). External radiotherapy is organized in two main ways. One, the most widespread, determines the treatment start date before treatment preparation. The other, called « fil de l'eau », prepares files as they arise and determines the treatment start date once the file is ready. We will examine the respective effects of these two organizational modes on the development dynamics of collective activities, on possible discontinuities and on care safety. We will show how cross-disciplinary collective activities guarantee continuity of patient care, as well as the development of quality treatment that guarantees patient safety. However, these cross-fonctionnal collective activities, and above all the articulations required for their development, are not taken into account in the sequential breakdown of the prescribed technical process. On the basis of this empirical knowledge, we open the discussion to design perspectives by highlighting what organizations should take into account to enable and support the development of real cross-fonctionnal collective activities, engaged in preparation
Capítulos de libros sobre el tema "Lack of fluidity"
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Breen, Richard y Walter Müller. "Social Mobility in the Twentieth Century in Europe and the United States". En Education and Intergenerational Social Mobility in Europe and the United States, 251–96. Stanford University Press, 2020. http://dx.doi.org/10.11126/stanford/9781503610163.003.0011.
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Summarizing the findings of the country chapters, this chapter addresses the question: How did intergenerational social mobility change over cohorts born in the first two-thirds of the twentieth century? What role, if any, did education play in this? As education expanded, its association to class origins weakened, especially among earlier-born cohorts—a strong indication that growing education equalization may have been important in increasing social fluidity. There is also a strong link between upward mobility and social fluidity, the former mostly driven by the expansion of higher-level white-collar jobs. Educational expansion, equalization, and rapid structural change in the US and European economies all contributed to greater social fluidity among people born before the middle of the century. For people born later, rates of downward mobility have increased: however, despite the lack of further educational equalization and less-pronounced structural change, social fluidity has remained unchanged.
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Thomas, Christine M. "Narrative Fluidity As A Generic Characteristic". En The Acts Of Peter, Gospel Literature, And The Ancient Novel, 72–86. Oxford University PressNew York, NY, 2003. http://dx.doi.org/10.1093/oso/9780195125078.003.0004.
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Abstract Although blessed with a relatively extensive and variegated set of witnesses, the Acts of Peter lack any extended testimony to the original Greek text beyond that of the martyrdom account, extant in two manuscripts. The only other testimony emerges from the fourth-century vellum fragment (P. Oxy 849). None of these three Greek witnesses attests the Acts of Peter in their original form. Each of the manuscripts of the martyrdom account (Codex Patmos 48 and Codex Vatopedi 79) represents an independent excerpting from the longer version of the Acts of Peter, for they begin the martyrdom account at different points. Vatopedi begins with the episode of the rich and promiscuous benefactress Chryse (=AcVer 30), but Patmos begins only after the death of Simon, at the episode concerning Agrippa’s four concubines (=AcVer 33). The vellum fragment (P. Oxy. 849) is also a truncation of the longer narrative.
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Kahn, Andrew. "8. Endings". En The Short Story: A Very Short Introduction, 107–18. Oxford University Press, 2021. http://dx.doi.org/10.1093/actrade/9780198754633.003.0008.
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‘Endings’ studies the endings of short stories. Poetic justice, comic relief, or tragic fulfilment could provide a shock ending. However, while conclusiveness may often mark short story endings, it is not to be taken for granted. Stories can leave dilemmas unresolved, lapsing into what can be called a ‘leisurely enigma’: the fluidity of personality and the open-endedness of the story seem commensurate in these instances. The power of a lack of finality in an ending might be that of a plot cliffhanger or, more memorably, an implication of vast consequences that can never be told and are not even latent in the story.
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Katsikas, Stefanos. "Conclusion". En Proselytes of a New Nation, 157–64. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780197621752.003.0006.
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The conclusion draws on the analysis in previous chapters, mainly Chapters 3 and 4, to address some theoretical questions about religious conversions and nation-building in Modern Greece. It argues that in Modern Greece of the nineteenth century religious conversions, including Muslim conversions, to Christian Orthodoxy were often a ticket to Greek national identity. By converting to Orthodox Christianity the converts often aspired to become Hellenes (i.e., Greek nationals). In so doing, Greece and the age of nationalism that Greece introduced in the Balkans set a pattern for religious conversions, including Muslim conversions to Christianity, in the region: Muslim converts often aspired to become nationals of the post-Ottoman country in which they lived. The conclusion also argues that Muslim conversion to Christian Orthodoxy was often facilitated by the weakness or lack of Ottoman institutions and the political, economic and social fluidity or havoc of the nineteenth century. It also discusses the reliability or lack thereof of Greek official documents concerning the conditions under which these conversions took place. What do these documents suppress, and what can be read between their lines, especially concerning neophyte child and adult slavery, molestation, sexual slavery, and concubinage?
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Vogel, Christoph N. "Ethical Monopolies". En Conflict Minerals, Inc., 109–30. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780197659649.003.0006.
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Abstract This chapter combines ethnographic insights with survey data into the impact of transnational minerals regulation. Through the prism of iTSCi, a private sector-led mineral traceability initiative, it explains how due diligence and transnational regulation impact local livelihoods, market access, and the fluidity of property regimes. The chapter explains how new, incoming regulation contributes to disarticulating supply chains and creating buyer-end monopolies. Justified by the need to offer due diligence by tracing mineral bags from mines to markets, iTSCi works through a territorializing logic of incorporating specific mining sites into its clean supply chains. This, the chapter highlights, has two major implications. In those sites included in the traceability scheme, local producers are forced into monopsony (buyer-end monopoly) and face pressure due to the lack of competition among trading houses and smelters. In other mining sites, not (yet) partaking in the scheme, miners are de facto excluded from access to legal markets. Both scenarios lead to decreasing local revenue. The chapter then closes with a broader reflection on the disjuncture between the demands of Western consumers and the livelihoods of mining communities in eastern Congo. It argues, similar to other policy fields, that the definition of global values and morality is a highly contested and diverse playing field.
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Beris, Antony N. y Brian J. Edwards. "Incompressible Viscoelastic Fluids". En Thermodynamics of Flowing Systems: with Internal Microstructure. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195076943.003.0013.
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In Part I, we discussed in detail the foundations of the bracket description of dynamical behavior, demonstrating how the generalized bracket is linked to the theories of both Hamiltonian mechanics and irreversible thermodynamics. Now it is time to discuss the various applications towards seemingly complex systems which are the main focus of this book. Specifically, we want to look at a variety of microstructured media of immediate concern in science and industry, and to illustrate the advantages of using the generalized bracket formalism over traditional techniques when developing system-particular models. As we shall also see, there are certain advantages to be gained even when we are simply expressing existing models in Hamiltonian form. The first subject that we wish to address is that of viscoelastic fluid dynamics. As the name implies, viscoelasticity characterizes the materials that possess properties intermediate to those of an elastic solid and a viscous fluid. The most characteristic property is that of limited (“fading”) memory: viscoelastic materials partially resume their previous deformation state upon removal of the externally applied forces; the smaller the duration of the application of the forces, the better the recovery. Materials of this type contain a certain degree of internal microstructure (e.g., polymeric solutions and melts, advanced composites, liquid crystals, etc.), and are very important in the processing industry where one wishes to combine the “processability” of the medium's fluidity with the “structural quality” of the internal architecture to obtain high strength/ low-weight final products. We can distinguish two types of viscoelasticity: viscoelastic solids and viscoelastic fluids characterized by the ability or lack of ability respectively, to support shear stresses at finite deformations. In the following we shall focus on the analysis of viscoelastic fluids although the approach followed applies and/or can be extended in a straightforward fashion to viscoelastic solids as well. For a description of solid viscoelasticity, the interested reader may consult one of the many excellent monographs in the area [Eringen, 1962, chs. 8, 10; Ferry, 1980; Sobotka, 1984; see also Tschoegl, 1989].
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Maury, Corinne. "Philippe Grandrieux’s Forest-matter: A Multisensory Place". En The Sense of Place in Contemporary Cinema, 75–82. Edinburgh University Press, 2022. http://dx.doi.org/10.3366/edinburgh/9781399501392.003.0007.
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In films, forests are often offered as landscapes to be contemplated or sceneries upon which the fantasies of the living are projected. This chapter demonstrates that forests can also represent completely different places. In Philippe Grandrieux’s movie Un Lac, the forest is a unifying place where, thanks to the voluptuously textured, highly mobile images, an organic fraternity is established between animals, humans and plants. The haptic powers of the camera that, in its motions, touches and caresses these heterogeneous singularities, follows a binding trajectory that creates a dermal alterity. This chapter analyses how Philippe Grandrieux instils a fluidity that favours the spreading out offorms, rather than their scaling. It is, in a way, a choreography of sensations. This chapter demonstrates that Grandrieux shows the power of the forest as a liberating form of dance, as a stimulating, nurturing, expansive network that allows bodies and senses to interact.
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Tannous, Katia y Joana Bratz Lourenço. "Fluid Dynamic and Mixing Characteristics of Biomass Particles in Fluidized Beds". En Innovative Solutions in Fluid-Particle Systems and Renewable Energy Management, 54–91. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8711-0.ch003.
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The study of fluid dynamic and mixing characteristics of biomass particles in fluidized beds is fundamental for comprehension of thermal conversion processes. In this chapter a review of literature showed a large lacks of technical information about the quality of fluidization and representative models concerning binary mixtures (biomass and inert). A case study was presented involving Eucalyptus grandis wood and tucumã endocarp in order to obtain fluid dynamic parameters such as the characteristic fluidization, velocity and porosity, and the bed expansion. These parameters were more significant for mixtures with smaller diameter and mass fraction ratios, and sphericity ratio, due to the facility of beds to fluidize. A map was presented to identify the limits of effective mixtures considering four classes as a function of the complete fluidization Reynolds' and Archimedes' numbers. Empirical correlations have been proposed and showed a good agreement with the experimental work.
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"lack a penis she has the joy (Jouissence) of her own embodied knowledge. In the same move 'the masculine' is relieved of the fear of castration, he need no longer define himself in relation to a mythical order. The perpetual, fearful repetition of masculist discourse can be replaced by fluid, multiple, contextual possibilities. We need to construct new desiring subjects in the ruins of the phallogocentrically enforced dualism. (Braidotti 1994b: 56) For archaeologists the potential of these new embodied subjectivities is enormous. In subversive moves we are freed to think in completely different ways as completely different knowing subjects, we are no longer fixed as masculine or feminine, in relation to reason and emotion, active or passive. In this new pre-phallocentric conceptual framework there are no dichotomous value structures in place, multiplicity and fluidity rule. When we identify ourselves as whole, complex agents, actively engaging with the social and cultural gendered categories we deny the confines of phallocentric opposition. The starting point for the project of sexual difference is the political will to assert the specificity of the lived female bodily experience . . . the project of sexual difference engages a will to reconnect the whole debate on difference to the bodily experience of women. (Braidotti 1994b: 140) I do not naively believe that simply by wishing the dichotomous structures away that they will disappear, but that we can disrupt the taken-for-granted nature of these phallocentric erections by asserting gendered locations which express multiplicity at the same time as asserting confident embodied knowledge. In this way the feminine will no longer be that which is lacking. As Judith Butler says: The feminine marks the limit of representability which would undo the pre-suppositions of representation itself. (Butler 1993b: 19) As academic archaeologists we are of course enmeshed in the symbols and meanings of the dominant masculist discourse, and in consequence we have 'known' ourselves and the world we live in relation to androcentric, phallocentric and heterosexual norms. If we are to tell radically different stories about the material culture with which we work we must make a terrifying leap into the interpretative spaces which are as yet largely inexpressible. We will use words which are already occupied by masculist meanings, and 'describe' social engagements in terms already dominated by the central, invasive phallus. We will in short be misunderstood. ACKNOWLEDGEMENTS". En Gender & Italian Archaeology, 40–41. Routledge, 2016. http://dx.doi.org/10.4324/9781315428178-11.
Texto completoActas de conferencias sobre el tema "Lack of fluidity"
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Ashrafi, Mahdi, Masoud Olia, Ashkan Vaziri y Hamid Nayeb-Hashemi. "Optimizing the Mechanical Properties of Wood Plastic Composites Using Fiber-Glass". En ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64043.
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Wood plastic composites (WPC) are widely used in the industry due to its durability, low cost, and anti-moisture properties in comparison with the natural wood. Recently, WPC are also being considered in musical instrument industry. In this research, we have produced flout shaped WPC samples using African black wood powder and Phenolic resin in a hot compression molding set-up. Initial WPC composites were produced by systematically changing the wood volume fraction. The results showed cracks developed in composites with more than 70% wood. This was related to formation of gas in the system during manufacturing and lack of fluidity in the system to flush the gases. Based on these results the optimum temperature, pressure and wood volume fraction for developing WPC in a form of a flute is developed. A series of experimental procedures were performed to improve mechanical properties of WPC samples by studying the effect short fiber-glass addition to the wood matrix prior to hot pressing. The results showed that the addition of short fiber did not improve the strength of WPC but rather than it reduced its strength compared to unreinforced composite. This was attributed to lack of bonding between short fibers and wood matrix. In contrast encapsulated wood particle composite in an E-glass/epoxy composite sheet before hot pressing showed the mechanical properties of wood composite are enhanced. A two layer unidirectional composite was sufficient for producing flute with desirable mechanical properties. On the basis of the experimental results, a very simple method to enhance the load-bearing capability of WPC which may allow producing reinforced WPC in the form of flout shape is developed.
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Bhattaram, Rohan, Ryan Reichert y Victoria Marino. "Novel Hydrogel for Stone Fragment Control During Ureteroscopic Lithotripsy". En 2022 Design of Medical Devices Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/dmd2022-1052.
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Abstract Surgical treatment of kidney stones commonly involves ureteroscopic lithotripsy with laser-assisted stone fragmentations. Particles that remain are considered “clinically insignificant” and are left behind, though these fragments are associated with downstream complications such as infection and stone reformation. The researchers aimed to develop a novel hydrogel that would prevent stone retropulsion intraoperatively and facilitate complete fragment removal. A novel inversely thermosensitive gel was developed which would theoretically stay solid to surround kidney stone, suspend stone fragments and would become liquid for gel removal. The aim of this study was to better understand the gel delivery mechanism considering its unique thermal properties. It was hypothesized that due to the gel’s thermal properties, an active cooling method, i.e. an intracatheter cooled guide wire, would be necessary to maintain gel fluidity to reach the intended destination. The researchers designed an experiment to test gel delivery through a 5 French, 70 cm long catheter surrounded by body temperature water with and without a cooled guide wire. We found there was no significant difference between both trial groups, indicating the gel does not require an active cooling method and can be administered directly. The lack of easy-to-use and cost-effective commercially available options to effectively reduce residual stone fragments presents a path for clinical adoption of the proposed hydrogel. Future trials will look into the fluid mechanics of gel administration and potential clinical outcomes such as stone free rates and rates of complications.
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Zhang, Weilong, Yuxuan Chen, Ying Huang, Yudong Ding, Qiang Liao y Min Cheng. "Study on the Flow Characteristics of Immiscible Mixtures on Vertical Wall". En ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-96871.
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Abstract The condensation heat transfer phenomenon of immiscible mixed vapors often occurs in industrial environments, such as the waste heat recovery process of raw coal gas, biomass gasification gas and other high-temperature gas. The immiscible mixed vapors can be condensed outside the heat exchange wall and generate an immiscible condensate film attached to the wall, so the flow characteristics of immiscible mixtures condensate have significant effect on the heat transfer performance of the heat exchanger. However, there is currently a lack of research on the flow mechanism of immiscible mixtures outside the wall, and there is no effective ways to control the flow pattern on the wall. Therefore, it is necessary to study the flow characteristics of immiscible mixtures outside the wall. In this work, silicone oil and water were used as immiscible mixtures, and the flow characteristics of immiscible mixtures on the vertical wall under different inlet flow velocities were studied by numerical simulations. The results showed that when the immiscible mixtures flowed to a stable state within all the range of study conditions, the silicone oil phase adhered to the wall in the form of a liquid film, while the water phase existed on the oil film. However, the difference of inlet velocity of immiscible mixtures could affect flow patterns. The immiscible mixtures presented a Film-drop flow pattern on the wall at a low inlet flow velocity, that is the water phase existed on the oil film in the form of droplets. As the inlet flow velocity of the mixtures increased, the immiscible mixtures presented a Film-drop and Channel flow pattern, and water existed on the oil film in the form of droplets and channels. During the flow process of the oil-water immiscible mixtures on the wall, the flow velocity of the oil film was always lower than that of the water phase under the different flow patterns. The oil phase dominated the overall flow velocity of the mixtures, and the overall fluidity of the mixtures liquid film could be increased by improving the flow velocity of oil phase. In addition, the flow of the water phase on the oil film could improve the flow velocity of the oil film, increased the shear stress of the oil-phase interface and disturbed the thickness of the oil film. The results can provide reference for the flow characteristics of immiscible condensate film on the wall surface.
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Schlu¨ter, Michael, Marko Hoffmann y Norbert Ra¨biger. "Characterization of Micro Fluidic Devices by Optical Measurements". En ASME 2007 5th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2007. http://dx.doi.org/10.1115/icnmm2007-30208.
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Micro fluidic devices are successfully in use for several applications in chemical engineering and biotechnology. Nevertheless, there is still no breakthrough for micro process engineering because of a lack in understanding the mechanisms for local hydrodynamics and mass transfer on micro scales. Micro Particle Image Velocimetry (μ-PIV) combined with Confocal Laser Scanning Microscopy (CLSM) enables the measurement of three-dimensional flow and concentration fields in micro devices for common stationary cases. By quantitative analysis of pressure drops, mixing qualities and residence time distributions an adjustment of micro reactor devices for the demands of chemical and biochemical reactions becomes possible.
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Wang, Zhengxu, Qingfeng Guo, Xiao Cai, Jingtian Zhang, Qing Zhao, Bo Li, Xuefeng Chen y Haiyang Gao. "Feasibility Evaluation of RF Heating Heavy Oil Reservoir Based on the Interaction Between Rocks and Electromagnetic Waves". En 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0226.
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ABSTRACT: Currently, radio frequency (RF) heating is emerging as an alternative to steam thermal recovery methods, owing to its numerous advantages including cleanliness, environmental friendliness, and cost-effectiveness. Achieving maximum heating distance and temperature during RF heating hinges on understanding the interaction between RF electromagnetic waves and rocks. To address this, the present study elucidates the RF heating mechanism, establishes geometric and mathematical models accounting for rock properties, and validates the mathematical model using laboratory experiments. The calculations reveal that lower specific heat, thermal conductivity, relative permittivity, and density of rocks, coupled with higher rock electrical conductivity, contribute to higher maximum reservoir temperatures. Additionally, the maximum heating distance increases with decreasing specific heat and density of rocks. Optimal values of thermal conductivity, relative permittivity, and electrical conductivity exist, maximizing the heating distance. These findings provide crucial guidance for optimizing rock properties, enhancing maximum heating temperature, and extending heating distances before implementing RF heating technology. 1. INTRODUCTION Heavy oil resources are abundant around the world and have broad development and utilization prospects. However, the characteristics of heavy oil with high viscosity and poor fluidity greatly increase the difficulty of extraction. Currently, the steam recovery technologies are widely used for heavy oil extraction, but it has gradually exposed many shortcomings such as high energy consumption, high carbon emissions, and difficulty in effectively exploiting low permeability, deep and thin layers of heavy oil. So many oil companies have no option but to develop new heavy oil mining technologies. A novel heavy oil extraction technology combined with electromagnetic power appears and is collectively referred to as "RF heating" by some oil companies and scholars. Some literatures (Godard and Rey-Bethbeder; Hu and Li et al.; Saeedfar and Lawton et al.; Bera and Babadagli, 2015; Ghannadi and Irani et al., 2016) have introduced its advantages, such as being environmentally friendly, highly heating efficiency, extracting resource in deep oil-bearing formation, avoiding extra heat loss and so on. In the early days, some scholars done some important researches of RF heating for improving heavy oil recovery. In recent years, there were some latest studies on the development of RF heating. world-renowned companies have conducted several researches on RF heating technology. The most representative one is a project called "ESEIEH" carried out in the Steepbank mine in Canada in 2012. Several antennas that emit RF electromagnetic waves are mainly used to radiate electromagnetic waves to reduce the viscosity of heavy oil (Rassenfoss, 2012). In this project, the first phase of field testing has been successfully completed. Besides, Bientinesi et al. conducted an RF heating experiment and proved that RF heating can effectively reduce the heavy oil viscosity (Bientinesi and Petarca et al., 2013). In 2017, Bera and Babadagli experimentally confirmed that Ni and Fe nanoparticles added to the heavy mixture can improve the heating efficiency of RF electromagnetic waves (Bera and Babadagli, 2017). Harris Company developed the "Heatwave" technology to exploit the abundant heavy oil and oil sand resources in Canada, and the field test was successful. In the test, an antenna was uses to radiate electromagnetic waves with the frequency of 6.78MHz into the reservoir, and the maximum heating distance reaches 12.5m (Wise and Patterson, 2016). Wang et al. studied the RF heating mode based on the antenna arrays in 2018 (Wang and Gao et al., 2018; Wang and Gao et al., 2018). The simulation results showed that the antenna array configuration can greatly increase the heating range of heavy oil reservoirs (Wang and Gao et al., 2019; Wang and Gao et al., 2020). However, based on the current research progress, there is a lack of research on the influence of the rock properties on the maximum temperature distribution and furthest heating distance, making it difficult to accurately predict the heating range and heating temperature.
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Shiari, Behrouz, Mahdi M. Sadeghi, Ali Darvishian y Khalil Najafi. "A Discrete Model for an Electrostatically Driven Micro-Hydraulic Actuator". En ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39019.
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High-force, large-deflection actuators are critical for devices such as valves and pumps used in micro-fluidic systems. The major technical impediment in improving the performance of the micro-actuators lies in the lack of understanding the physical phenomena and their interactions of electric, mechanical, and fluidic fields for performing their intended functions. Because of the complexity of the actuator, the fully coupled numerical analysis such as finite element analysis is extremely expensive. Here, we introduce a discrete model of an Electrostatic Micro-Hydraulic (EMH) actuator. The model considers all dynamic forces which are involved in a time operation of the hydraulic actuator cell and covers three major physics: electrostatic, mechanical and fluidic. The physics have been coupled together to investigate the dynamic of the device. The discrete dynamic model developed in this work may be used for simple yet accurate predictions of dynamic performance of such actuators, and is preferable to more complicated and very expensive coupled numerical models. The analysis relies on physics-based equations and can be modified to accommodate different chamber geometries, different material properties and different working fluids. Results from the analytical model compare favorably with experimental measurements.
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Zhang, Yahui, Howard Chen y Ibrahim T. Ozbolat. "Characterization of Printable Micro-Fluidic Channels for Organ Printing". En ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-85622.
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Organ printing is a complex and challenging process in execution due to the lack of fundamental understanding of tissue and organ formation, and problems associated with giving the organ-conforming 3D shapes. One of the major challenges is the inclusion of blood vessel-like channels between layers to support cell viability in terms of nutrients and oxygen transport. Tissue scaffolds have been widely used in generation of replacement tissue by providing mechanical support and fluid nutrients, but complications with scaffold degradation and the corresponding adverse effects on extra cellular matrix still present major challenges. This paper introduces a new approach in tissue scaffolding for cellular assembly to minimize these problems. This research investigates the manufacturability of novel printable micro-fluidic channels, where the micro-fluidic channels support mechanical integrity as well as enable fluid transport in 3D. A pressure-assisted solid freeform fabrication platform is developed with co-axial needle dispenser unit to print hollow hydrogel filaments, which will later be used to support nutrients and oxygen transport through the printed cell assembly. The dispensing rheology is studied and the effect of material property on structural formation of hollow filaments is analyzed in this paper. Sample structures are printed through the computer-controlled system. In experiments with sodium alginate, 4% CaCI2-4% alginate solution combination results in the smallest core and filament diameter. In experiments with chitosan on the other hand, 3% chitosan-1% NaOH combination brings the smallest core and filament diameter.
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Isava, Monica y Amos G. Winter. "A Theoretical Investigation of the Critical Timescales Needed for Digging in Dry Soil Using a Biomimetic Burrowing Robot". En ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-47852.
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RoboClam is a bio-inspired robot that digs into underwater soil efficiently by expanding and contracting its valves to fluidize the substrate around it, thus reducing drag. This technology has potential applications in fields such as anchoring, sensor placement, and cable installation. Though there are similar potential applications in dry soil, the lack of water to advect the soil particles prevents fluidization from occurring. However, theoretically, if the RoboClam contracts quickly enough, it will achieve a zero-stress state that will allow it to dig into dry soil with very little drag, independent of depth. This paper presents a theoretical model of the two modes of soil collapse to determine how quickly a device would need to contract to achieve this zero-stress state. It was found that a contraction time of 0.02 seconds would suffice for most soils, which is an achievable timescale for a RoboClam-like device.
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Vijayaraghavan, Athulan, Stephen V. Jayanathan, Moneer M. Helu y David A. Dornfeld. "Design and Fabrication of a Roller Imprinting Device for Microfluidic Device Manufacturing". En ASME 2008 International Manufacturing Science and Engineering Conference collocated with the 3rd JSME/ASME International Conference on Materials and Processing. ASMEDC, 2008. http://dx.doi.org/10.1115/msec_icmp2008-72202.
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Microfluidic devices are gaining popularity in a variety of applications, ranging from molecular biology to bio-defense. However, the widespread adoption of this technology is constrained by the lack of efficient and cost-effective manufacturing processes. This paper focuses on the roller imprinting process, which is being developed to rapidly and inexpensively fabricate micro-fluidic devices. In this process, a cylindrical roll with raised features on its surface creates imprints by rolling over a fixed workpiece substrate and mechanically deforming it. Roller imprinting aims to replace processes that were developed for laboratory scale prototyping which tend to not be scalable and have high equipment requirements and overheads. We discuss the limitations of PDMS soft lithography in large-scale manufacture of microfluidic devices. We also discuss the design, fabrication, and testing of a simple roller imprinting device. This imprinter has been developed based on the principles of precision machine design and is implemented using a three-axis machine tool for actuation and position measurement. A framework for the micro-machining of precision imprint rolls is also presented.
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Yang, Jui-Ming y Philip R. LeDuc. "Three-Dimensional Laminar Flow for Localized Cellular Stimulation". En ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61643.
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Stimulation of living mammalian cells is primarily accomplished by the delivery of chemical agents to single cells or cell populations. Due to the fast response time of diffusion for these agents over the small size scale of individual cells, localized stimulation is limited. Currently, there are alternate techniques that can produce localized gradients of chemical stimulants over single cells, but they lack the ability for long time scale events that are requisite for many cellular processes because of this diffusion limitation. We have developed a device that is able to create chemical agent separation in three dimensions along distinct boundaries that can be applied to cells. As many techniques are two-dimensionally constrained, this provides us with a more physiologically relevant system for investigating cellular signal transduction and can allow basal to apical activation separations. To accomplish this, multiple flow paths were introduced to manipulate spatiotemporally distinct regions inside a single capillary channel. Solutions that flow laminarly inside these fluidic channels deliver predefined chemicals to specific locations without turbulent mixing. Separation using this system under laminar flows created not only side by side domains in this capillary but also vertical as well. This device has multiple potential applications both in cell and molecular biology as well as in fluid dynamics and fabrication processes.