3 resultados para Critical Reynolds Number

em Bucknell University Digital Commons - Pensilvania - USA


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We consider the inertially driven, time-dependent biaxial extensional motion of inviscid and viscous thinning liquid sheets. We present an analytic solution describing the base flow and examine its linear stability to varicose (symmetric) perturbations within the framework of a long-wave model where transient growth and long-time asymptotic stability are considered. The stability of the system is characterized in terms of the perturbation wavenumber, Weber number, and Reynolds number. We find that the isotropic nature of the base flow yields stability results that are identical for axisymmetric and general two-dimensional perturbations. Transient growth of short-wave perturbations at early to moderate times can have significant and lasting influence on the long-time sheet thickness. For finite Reynolds numbers, a radially expanding sheet is weakly unstable with bounded growth of all perturbations, whereas in the inviscid and Stokes flow limits sheets are unstable to perturbations in the short-wave limit.

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Biodegradable nanoparticles are at the forefront of drug delivery research as they provide numerous advantages over traditional drug delivery methods. An important factor affecting the ability of nanoparticles to circulate within the blood stream and interact with cells is their morphology. In this study a novel processing method, confined impinging jet mixing, was used to form poly (lactic acid) nanoparticles through a solvent-diffusion process with Pluronic F-127 being used as a stabilizing agent. This study focused on the effects of Reynolds number (flow rate), surfactant presence in mixing, and polymer concentration on the morphology of poly (lactic acid) nanoparticles. In addition to looking at the parameters affecting poly (lactic acid) morphology, this study attempted to improve nanoparticle isolation and purification methods to increase nanoparticle yield and ensure specific morphologies were not being excluded during isolation and purification. The isolation and purification methods used in this study were centrifugation and a stir cell. This study successfully produced particles having pyramidal and cubic morphologies. Despite successful production of these morphologies the yield of non-spherical particles was very low, additionally great variability existed between redundant trails. Surfactant was determined to be very important for the stabilization of nanoparticles in solution but appears to be unnecessary for the formation of nanoparticles. Isolation and purification methods that produce a high yield of surfactant free particles have still not been perfected and additional testing will be necessary for improvement.¿

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Reform is a word that, one might easily say, characterizes more than any other the history and development of Buddhism. Yet, it must also be said that reform movements in East Asian Buddhism have often taken on another goal—harmony or unification; that is, a desire not only to reconstruct a more worthy form of Buddhism, but to simultaneously bring together all existing forms under a single banner, in theory if not in practice. This paper explores some of the tensions between the desire for reform and the quest for harmony in modern Japanese Buddhism thought, by comparing two developments: the late 19th century movement towards ‘New Buddhism’ (shin Bukkyō) as exemplified by Murakami Senshō 村上専精 (1851–1929), and the late 20th century movement known as ‘Critical Buddhism’ (hihan Bukkyō), as found in the works of Matsumoto Shirō 松本史朗 and Hakamaya Noriaki 袴谷憲昭. In all that has been written about Critical Buddhism, in both Japanese and English, very little attention has been paid to the place of the movement within the larger traditions of Japanese Buddhist reform. Here I reconsider Critical Buddhism in relation to the concerns of the previous, much larger trends towards Buddhist reform that emerged almost exactly 100 years previous—the so-called shin Bukkyō or New Buddhism of the late-Meiji era. Shin Bukkyō is a catch-all term that includes the various writings and activities of Inoue Enryō, Shaku Sōen, and Kiyozawa Manshi, as well as the so-called Daijō-hibussetsuron, a broad term used (often critically) to describe Buddhist writers who suggested that Mahāyāna Buddhism is not, in fact, the Buddhism taught by the ‘historical’ Buddha Śākyamuni. Of these, I will make a few general remarks about Daijō-hibusseturon, before turning attention more specifically to the work of Murakami Senshō, in order to flesh out some of the similarities and differences between his attempt to construct a ‘unified Buddhism’ and the work of his late-20th century avatars, the Critical Buddhists. Though a number of their aims and ideas overlap, I argue that there remain fundamental differences with respect to the ultimate purposes of Buddhist reform. This issue hinges on the implications of key terms such as ‘unity’ and ‘harmony’ as well as the way doctrinal history is categorized and understood, but it also relates to issues of ideology and the use and abuse of Buddhist doctrines in 20th-century politics.