933 resultados para HORIZONTAL MICROCHANNELS


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Using a model derived from lubrication theory, we consider the evolution of a thin viscous film coating the interior or exterior of a cylindrical tube. The flow is driven by surface tension and gravity and the liquid is assumed to wet the cylinder perfectly. When the tube is horizontal, we use large-time simulations to describe the bifurcation structure of the capillary equilibria appearing at low Bond number. We identify a new film configuration in which an isolated dry patch appears at the top of the tube and demonstrate hysteresis in the transition between rivulets and annular collars as the tube length is varied. For a tube tilted to the vertical, we show how a long initially uniform rivulet can break up first into isolated drops and then annular collars, which subsequently merge. We also show that the speed at which a localized drop moves down the base of a tilted tube is non-monotonic in tilt angle.

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In this thesis, producing ability of electricity by horizontal tidal current turbines and installing possibility of these turbines on bridge's piers in the marine environments has been studied to reduce primary implementation costs and make the plan, economical. To do this and to study its feasibility, the exerted forces from installing horizontal tidal current turbines were compared with the forces applied to the bridge structure during designing process (given in the Standards). Then, the allowable ranges of the overloading which is tolerable by the piers of the bridge were obtained. Accordingly, it is resulted that for installing these turbines, the piers of the existing bridges are required to be strengthened. Because of increasing usage of renewable powers and as a suggestion, the exerted forces from installing turbine for loading coefficients of different Standards are given. Finally as an example, preliminary designing of a horizontal tidal current turbine was carried out for Gesham Channel and the forces exerted from turbine to the bridge's pier were calculated for the future usage in order to create a test site of real dimensions.

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Cálculo y diseño de una grúa torre desmontable con brazo horizontal giratorio destinada a la elevación y transporte de material de construcción en edificios de viviendas

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This paper generalizes the model of Salant et al. (1983; Quarterly Journal of Economics, Vol. 98, pp. 185–199) to a successive oligopoly model with product differentiation. Upstream firms produce differentiated goods, retailers compete in quantities, and supply contracts are linear. We show that if retailers buy from all producers, downstream mergers do not affect wholesale prices. Our result replicates that of Salant's, where mergers are not profitable unless the size of the merged firm exceeds 80 per cent of the industry. This result is robust to the type of competition.

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Se cuestiona la abstención de registro de un libro de actas de un consejo de copropietarios.

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Current pear pruning making use of pneumatic shears still is a very labour intensive operation. The Proder project “Avaliação da poda mecânica em pomares de pera” was designed to contribute to solutions that would reduce the present dependence in labour and therefore to promote a reduction in pruning costs. This paper shows the results of a trial made to evaluate the influence of mechanical topping in manual pruning complement field work and pear yield. Topping was performed using a Reynolds 6DT 3.0m cutting bar with six hydraulic-driven circular disc-saws mounted in the three point tractor linkage system. The field trial was performed in a commercial orchard with 20 years, planted in an array of 4m x 2m with tree lines oriented in North-South direction. Trees were trained as the central leader system. In this trial, in a randomised complete block design with four replications, two treatments are being compared leading to 8 plots with one line of 14 trees per plot. The treatments tests were: T1 - manual pruning performed by workers using pneumatic shears, in each year; T2 - Topping the canopy parallel to the ground, using a discs-saw pruning machine mounted in a front loader of an agricultural tractor, followed by manual pruning complement performed by workers with pneumatic shears. Tree height and width was measured, before and after pruning. Work was timed and pear yields evaluated. Mechanical topping seems to be effective in the control of tree height, which can contribute to increase 14% of work rates on manual pruning complement. No significant differences in pear yield were found between treatments.

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Avaliou-se, sob condições controladas, a resistência de genótipos de seringueira ao mal-das-folhas.

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Most corporate entrepreneurship studies have focused on either innovation, venturing or strategic renewal making comparison between the antecedents of all three aspects of corporate entrepreneurship difficult. Moreover, studies on corporate entrepreneurship hardly address organizational antecedents, while simultaneously managing and organizing CE and mainstream activities has been seen as a major challenge for incumbent firms. Our findings show that organizational ambidexterity has strong and differential effects on venturing, innovation and renewal. We find, for example, that innovation is affected by horizontal integration, while strategic renewal is significantly influenced by integration on top management team level.

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This study investigated the longitudinal performance of 378 students who completed mathematics items rich in graphics. Specifically, this study explored student performance across axis (e.g., numbers lines), opposed-position (e.g., line and column graphs) and circular (e.g., pie charts) items over a three-year period (ages 9-11 years). The results of the study revealed significant performance differences in the favour of boys on graphics items that were represented in horizontal and vertical displays. There were no gender differences on items that were represented in a circular manner.

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Networks are having a profound impact on the way society is organised at the local, national and international level. Networks are not ‘business as usual’. The defining feature of networks and a key indicator for their success is the strength and quality of the interactions between members. This relational power of networks provides the mechanism to bring together previously dispersed and even competitive entities into a collective venture. Such an operating context demands the ability to work in a more horizontal, relational manner. In addition a social infrastructure must be formed that will support and encourage efforts to become more collaborative. This paper seeks to understand how network members come to know about working in networks, how they work on their relationships and create new meanings about the nature of their linked work. In doing so, it proposes that learning, language and leadership, herein defined as the ‘3Ls’ represent critical mediating aspects for networks.

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Collaborative networks have come to form a large part of the public sector’s strategy to address ongoing and often complex social problems. The relational power of networks, with its emphasis on trust, reciprocity and mutuality provides the mechanism to integrate previously dispersed and even competitive entities into a collective venture(Agranoff 2003; Agranoff and McGuire 2003; Mandell 1994; Mandell and Harrington 1999). It is argued that the refocusing of a single body of effort to a collective contributes to reducing duplication and overlap of services, maximizes increasingly scarce resources and contributes to solving intractable or 'wicked’problems (Clarke and Stewart 1997). Given the current proliferation of collaborative networks and the fact that they are likely to continue for some time, concerns with the management and leadership of such arrangements for optimal outcomes are increasingly relevant. This is especially important for public sector managers who are used to working in a top-down, hierarchical manner. While the management of networks (Agranoff and McGuire 2001, 2003), including collaborative or complex networks (Kickert et al. 1997; Koppenjan and Klijn 2004), has been the subject of considerable attention, there has been much less explicit discussion on leadership approaches in this context. It is argued in this chapter that the traditional use of the terms ‘leader’ or ‘leadership’ does not apply to collaborative networks. There are no ‘followers’ in collaborative networks or supervisor-subordinate relations. Instead there are equal, horizontal relationships that are focused on delivering systems change. In this way the emergent organizational forms such as collaborative networks challenge older models of leadership. However despite the questionable relevance of old leadership styles to the contemporary work environment, no clear alternative has come along to take its place.