COMPARISON ANALYSIS OF CORRELATIONS FOR INTERFACIAL FRICTION FACTOR APPLIED IN GAS-LIQUID ANNULAR FLOW IN VERTICAL PIPES

Gas-liquid flows in pipes can occur in the form of an annular pattern in which the liquid flows as a thin film at pipe wall and the gas flows as a core in pipe center. This flow pattern is often encountered at boiling and condensation processes, for example, in industries of steam generation, cooling or petroleum. In annular flow, the interfacial friction factor is one of the important closing parameters for the definition of the interfacial shear stress and consequently the pressure gradient. In the literature, several correlations are found to estimate the interfacial friction factor. The main objective of this work is to carry out a comparative analysis of some these correlations against experimental data also obtained from the literature. The features and limitations of each correlation were observed, as well as the accuracy of each in relation to experimental data. The results obtained demonstrate that correlations analyzed, present relatively satisfactory results, despite the different characteristics of the correlations, however, it is necessary to carry out more extensive analyses involving others correlations and sets of experimental data

Compact Mach-Zehnder acousto-optic modulator

The authors demonstrate a compact optical waveguidemodulator based on a Mach-Zehnder interferometer driven by surface acoustic waves. The modulator was monolithically fabricated on GaAs with an active region length of approximately 15μm. It yields peak-to-peak modulation exceeding 90% of the average transmission and operation in the gigahertz frequency range

National culture and earnings management in developed and emerging countries

Purpose This study investigates how the association between national culture and earnings management compares between developed and emerging countries. Design/methodology/approach The empirical analysis relies on a sample of 6,313 firm-year observations from 11 emerging markets and 27,605 firm-year observations from 22 developed countries. The authors use ordinary least squares regression methods to test the hypotheses of the study. Findings Based on Hofstede's (2011) cultural dimensions, the authors find that firms from countries with a higher level of uncertainty avoidance and individualism are less likely to engage in earnings management, but the effect of uncertainty avoidance (individualism) is more (less) pronounced in the emerging countries. Moreover, the authors demonstrate that firms from emerging (developed) countries with higher levels of power distance and masculinity are less (more) likely to engage in earnings management. Finally, the authors find evidence of a trade-off between accruals-based and real earnings management in firms from countries with greater long-term orientation and an indulgence cultural dimension. Originality/value This paper adds to the literature by theoretically discussing and empirically analysing the role that developed and emerging countries' development plays on the effect of national culture on earnings management.info:eu-repo/semantics/acceptedVersio

E 1 Gap Of Wurtzite Inas Single Nanowires Measured By Means Of Resonant Raman Spectroscopy

Indium arsenide nanowires were synthesized with an intermixing of wurtzite and zincblende structure by chemical beam epitaxy with the vapor-liquid-solid mechanism. Resonant Raman spectroscopy of the transverse optical phonon mode at 215cm -1 reveals an E 1 gap of 2.47 eV which is assigned to the electronic band gap at the A point in the indium arsenide wurtzite phase. © 2011 American Institute of Physics.1399473474 Int. Union Pure Appl. Phys. (IUPAP C8 Comm.),Korean Ministry of Education, Science and Technology,Seoul Metropolitan Government,Office of Naval Research Global,Korea Tourism OrganizationDick, K.A., (2008) Prog. Cryst. Growth Charact. Mater., 54, pp. 138-173Milnes, A.G., Polyakov, A.Y., (1993) Mater. Sci. Eng. B, 18, pp. 237-259Dayeh, S.A., Susac, D., Kavanagh, K.L., Yu, E.T., Wang, D., (2009) Adv. Mater., 19, pp. 2102-2108Cardona, M., (1961) J. Appl. Phys., 32 (SUPPL.), pp. 2151-2155Antoci, S., Reguzzoni, E., Samoggia, G., (1970) Phys. Rev. Lett., 24, pp. 1304-1307Arguello, C.A., Rousseau, D.L., Porto, S.P.S., (1969) Phys. Rev., 181, pp. 1351-136

COMPARISON ANALYSIS OF CORRELATIONS FOR INTERFACIAL FRICTION FACTOR APPLIED IN GAS-LIQUID ANNULAR FLOW IN VERTICAL PIPES

Gas-liquid flows in pipes can occur in the form of an annular pattern in which the liquid flows as a thin film at pipe wall and the gas flows as a core in pipe center. This flow pattern is often encountered at boiling and condensation processes, for example, in industries of steam generation, cooling or petroleum. In annular flow, the interfacial friction factor is one of the important closing parameters for the definition of the interfacial shear stress and consequently the pressure gradient. In the literature, several correlations are found to estimate the interfacial friction factor. The main objective of this work is to carry out a comparative analysis of some these correlations against experimental data also obtained from the literature. The features and limitations of each correlation were observed, as well as the accuracy of each in relation to experimental data. The results obtained demonstrate that correlations analyzed, present relatively satisfactory results, despite the different characteristics of the correlations, however, it is necessary to carry out more extensive analyses involving others correlations and sets of experimental data

Dermatomyositis and Breast Calcinosis

The authors report a rare case of dermatomyositis diagnosed at the Mastology Sector of the Division of Gynecology of the Federal University of São Paulo - Escola Paulista de Medicina, which caused breast deformity due to formation of bilateral dystrophic calcifications.Os autores relatam caso raro de dermatomiosite diagnosticado no Setor de Mastologia da Disciplina de Ginecologia da Universidade Federal de São Paulo (UNIFESP) - Escola Paulista de Medicina, causando deformidade mamária devido à formação de calcificações distróficas bilateralmente.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Setor de MastologiaUNIFESP, EPM, Setor de MastologiaSciEL

The trauma and acute care surgeon in the COVID-19 pandemic era

The World Health Organization recognized in March 2020 the existence of a pandemic for the new coronavirus that appeared in China, in late 2019, and whose disease was named COVID-19. In this context, the SBAIT (Brazilian Society of Integrated Care for Traumatized Patients) conducted a survey with 219 trauma and emergency surgeons regarding the availability of personal protective equipment (PPE) and the role of the surgeon in this pandemic by means of an electronic survey. It was observed that surgeons have been acting under inadequate conditions, with a lack of basic supplies as well as more specific equipment such as N95 masks and facial shields for the care of potential victims who may be contaminated. The latter increases the risk of contamination of professionals, resulting in potential losses in the working teams. Immediate measures must be taken to guarantee access to safety equipment throughout the country, since all trauma victims and/or patients with emergency surgical conditions must be treated as potential carriers of COVID-19