Stability of plane Poiseuille-Couette flows of a piezo-viscous fluid

We examine stability of fully developed isothermal unidirectional plane Poiseuille--Couette flows of an incompressible fluid whose viscosity depends linearly on the pressure as previously considered in Hron01 and Suslov08. Stability results for a piezo-viscous fluid are compared with those for a Newtonian fluid with constant viscosity. We show that piezo-viscous effects generally lead to stabilisation of a primary flow when the applied pressure gradient is increased. We also show that the flow becomes less stable as the pressure and therefore the fluid viscosity decrease downstream. These features drastically distinguish flows of a piezo-viscous fluid from those of its constant-viscosity counterpart. At the same time the increase in the boundary velocity results in a flow stabilisation which is similar to that observed in Newtonian fluids with constant viscosity

Stability of plane Poiseuille flow of a fluid with pressure-dependent viscosity

We study the linear stability of a plane Poiseuille flow of an incompressible fluid whose viscosity depends linearly on the pressure. It is shown that the local critical Reynolds number is a sensitive function of the applied pressure gradient and that it decreases along the channel. While in the limit of small pressure gradients conventional results for a pressure-independent Newtonian fluid are recovered, a significant stabilisation of the flow and an elongation of the critical disturbance wavelength are observed when the longitudinal pressure gradient is increased. These features drastically distinguish the stability characteristics of a piezo-viscous flow from its pressure-independent Newtonian counterpart

Trade Liberalization and Development in ICT Sector and its impact on household welfare in Viet Nam

The ICT sector in Viet Nam had not been developed until the 1980s. However, over the last decade of rapid growth, it has had a powerful impact on many aspects of life in this country. Although the ICT sector is still at an early stage of development and lags behind many other countries in the region, the government of Viet Nam made strong commitments to upgrade the nation’s ICT capability and implemented significant reforms in terms of trade and investment liberalization in ICT sector over the last decade.Trade Liberalization, ICT, Household welfare, Viet Nam

Revisiting plane Couette-Poiseuille flows of a piezo-viscous fluid

We re-examine fully developed isothermal unidirectional plane Couette-Poiseuille flows of an incompressible fluid whose viscosity depends linearly on the pressure as previously considered in Hron et al 2001. We show that the conclusion made there that, in contrast to Newtonian and power-law fluids, piezo-viscous fluids allow multiple solutions is not justified, and that the inflection velocity profiles reported in Hron et al 2001 cannot exist. Subsequently, we undertake a systematic parametric study of these flows and identify three distinct families of solutions which can exist in the considered geometry. One of these families has no similar counterpart for fluids with pressure-independent viscosity. We also show that the critical wall speed exists beyond which Poiseuille-type flows are impossible regardless of the magnitude of the applied pressure gradient. For smaller wall speeds channel choking occurs for Poiseuille-type flows at large pressure gradients. These features distinguish drastically piezo-viscous fluids from their Newtonian and power-law counterparts

The Developmental Role of Attentional Control in Language Learning

Increasing research suggests that bilingual children have advanced (relative to monolingual children) development of attentional control. The present study includes 94 bilingual and 110 monolingual child participants from a variety of language and age groups (2.5 to 5 year-olds) to systematically investigate how early learning/exposure to more than one language is related to the developmental shift of attention and its possible implications in early language learning. Results from the present study support an initial bilingual advantage in the Attention Network Test (ANT; a nonlinguistic task measuring attentional shifting), with monolinguals demonstrating comparable performance over time. Furthermore, significant relationships were found among overall accuracy, response time, the efficiency of individual attentional networks of the ANT and the MacArthur Bates Communicative Development Inventories (MCDI; a standardized parental report used to assess children's lexical growth). Moreover, this was specifically the case for the selected lexical category of adjectives. The current study provides new insights into the early developmental trajectory of attention among monolingual and bilingual children and how effective attention may be relevant developmental component for early language learning.Psychology, Department o

The Continuing of Organicism: An Enviro-organic Form Integrating to the Built Environment

Humans have engaged nature as an ideal paradigm of form and function since time immemorial. Within the organic paradigm, architecture may be seen to constitute an organic relationship with nature in any climatic, cultural and social condition. Though often rejected in canonical modern architecture, organic forms have been manifested, in various forms, and with different purposes. Recently, some modern organic movements have emerged, such as those following principles of biomorphic form and biomimicry. Unfortunately, these movements often fail to more fully embrace organicism in the totality and depth of their relationship to the natural. Following D‘Arcy Thompson‘s On Growth and Form, this research aims at uncovering the key attributes of natural form, in order to allow the design of enviro-organic form. Such form is defined as one that opens to the natural world, facilitating the making of architecture that sustains human life and nature today and in the future. In order to carry this out, the research offers graphic and analytic tools that help aid understanding into what organic architecture is, and how we can undertake a design process leading to enviro-organic form. The research concentrates on the analogies between architectural form and natural forms. The outcomes are, to paraphrase D‘Arcy Thompson, explained by the, “equilibrium resulting from the interaction or balance of forces.” Natural forms result from the fitness of the resolution of inside and outside living forces. Similarly, architectural organic form, as embodied in indigenous or vernacular architecture, result from integrating environmental and socio-cultural forces. Because architecture must adapt to cultural and social changes, human built environments are argued to be functionally more complex than those made by animals, as seen for example in a bird-nest, spider-web, or ant-hill. Since vernacular architecture is largely shaped by instinct, and in response to specific local place and culture, vernacular forms are not typically suited to be applied directly to the needs of contemporary culture. Geometry is proposed as the medium for historical examination of the incidental analogy between nature and organic architecture, for the rational fitness of integrating between natural principles and architecture disciplines, and for the selective transformation of enviro-organic forms that promise to more fully integrate the works of humans into the natural environment

Echoes from the Past: An Inquiry into the Nature and Causes of the Vietnam War

About the author Duc Tran is from Hanoi, Vietnam and graduated from Brandeis University in Waltham, MA in December 2013 with B.A. degrees in Economics and Mathematics. He wrote this paper when he studied History at Truman State University in Kirksville, MO. He hopes to pursue a career in economic policy management and public administration. But he desires to teach and write history after retiring from his public service