Publisher Summary This chapter provides an overview of the analytical and experimental hydrodynamics and heat transfer studies of Newtonian and non-Newtonian fluids in laminar and turbulent flow through rectangular tubes. The chapter in particular focuses on the rectangular duct geometry, with emphasis on the friction factor and heat transfer behavior of non-Newtonian fluids. It is recognized that non-Newtonian behavior is generally more complicated than Newtonian flow. In the case of non-Newtonian fluids, the theoretical predictions yield low estimates of the heat transfer under laminar flow conditions. The fact that the available experimental heat transfer measurements lie above the predictions could reflect an inadequacy in the analytical model. For non-Newtonians in turbulent flow through rectangular channels, the situation is even more complicated. Some non-Newtonian fluids act as pseudoplastics, showing some reduction in friction and heat transfer as compared with a Newtonian fluid. Other non-Newtonian fluids experience large reductions in the friction factor and in heat transfer under turbulent flow conditions.

Heat transfer to newtonian and non-newtonian fluids in rectangular ducts

Publisher Summary This chapter focuses on heat transfer in non-Newtonian fluids. This chapter illustrates that useful engineering studies which deal with transport processes in non-Newtonian fluids have been underway for the past several years. Earlier heat transfer reviews therefore serves primarily to separate a very small number of useful contributions from the substantial mass of trivial, misleading or even incorrect concepts and interpretations available at that time. This chapter provides the general survey of rheological behavior necessary for an understanding of transport processes in non-Newtonian fluids. The fluid classification system of interest is based on the form of the constitutive equations used to describe the properties of real fluids quantitatively. The chapter discusses all or more recent publication of work on heat transfer to non-Newtonian fluids since 1954 and provides an overview of the current state of the art. The chapter also describes fluid mechanical studies dealing with non-Newtonian materials.

Heat Transfer in Non-Newtonian Fluids

Laminar forced convection heat transfer of a non-newtonian fluid in a square duct

Advances in Chemical Engineering Vol. 5. Edited by Thomas B. Drew, John W. Hoopes jun., Theodore Vermeulen and Giles R. Cokelet. Pp. x + 317. (New York: Academic Press, Inc.; London: Academic Press, Inc. (London), Ltd., 1964.) 100s.

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Advances in Chemical Engineering

Publisher Summary This chapter discusses the phenomena of heat and mass transport in processes involving rheologically complex materials, especially with regard to the implications of shear dependent viscosity and viscoelasticity of materials. The highly non-linear and strongly coupled nature of the field equations preclude the possibility of analytical results, and therefore, usually numerical solutions are sought, even for as simple a situation as that of laminar flow of a purely viscous fluid in a circular tube. The thermo-physical properties of the commonly used non-Newtonian materials are described. It is clear that in the laminar region the shear thinning enhances heat transfer and reduces pressure drop as compared with a Newtonian fluid. The temperature dependent viscosity facilitates the heating of fluids while it impedes the efficacy of cooling of fluids for shear thinning materials. While from a heat transfer standpoint, the circular geometry is the most efficient one but when pressure loss is also of concern, short pipe lengths are preferred.

Heat and mass transfer in rheologically complex systems

The momentum and energy integral method of von Karman and Pohlhausen is used to solve the entrance heat transfer problem for a non-Newtonian fluid in a flat duct. The initial temperature and velocity profiles are assumed to be flat. The fluid is assumed to obey the Ostwald-de Wael model and its physical properties are assumed to be constant. Dimensionless expressions for temperature and velocity profiles are obtained by numerical methods.



The results of this investigation indicate that, similar to the case of Newtonian fluid, the parameters which influence entrance heat transfer are x/b ratio, Reynolds number and Prandtl number, provided these groups are properly defined.



La methode tenant compte du momentum et de l'energie de von Karman et de Pohlhausen est utilisee pour resoudre le probleme de la transmission de chaleur a l'entree d'un conduit plat pour un fluide non-Newtonien. Les profils initiaux de temperature et vitesse sont supposes uniformes. Le fluide est conforme au modele Ostwald-de Wael et ses proprieties sont supposees constantes. Les expressions sans dimensions sont obtenues a l'aide d'analyses numeriques pour les profils de temperature et vitesse.



Les resultats de cette recherche indiquent que, similarement au cas des fluides non-Newtoniens, les parametres influencant la transmission de chaleur a l'entree, sont x/b, Re et Pr en autant que ces groupes son definis adequatement.

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Simultaneous development of velocity and temperature profiles for laminar flow of a non-Newtonian fluid in the entrance region of flat ducts


Purpose
This study aims to examine the effect of corporate risk disclosure on investment efficiency. This study also seeks to contribute to existing literature of corporate risk disclosure by investigating voluntary and mandatory risk disclosure and its effect on the investment efficiency.


Design/methodology/approach
This study used two measures of corporate risk disclosure, level and quantity of corporate risk disclosure. A content analysis approach is adopted for non-financial Malaysian firms over the period 2010–2018.


Findings
The empirical results show that level of corporate risk disclosure leads toward efficient investment, whereas quantity of corporate risk disclosure causes inefficient investment when firms disclose more voluntary risks. Further, categorizing corporate risk disclosure into mandatory and voluntary risk disclosure, this study finds that voluntary risk disclosure tends to have higher investment inefficiency, while no evidence was found for mandatory risk disclosure.


Originality/value
This paper contributes to narrow stream of research investigating corporate risk disclosure through level and quantity contributing to the understanding of the level and quantity of risk disclosure in determining organizational investment efficiency.


Pushing a balloon: does corporate risk disclosure matter for investment efficiency?

It is undeniable that corporate governance is an important element towards the capital structure across industries as it affects the financial decision which drives the companies’ reputation and revenue. However, the big question is what drives the relationship of corporate governance and capital structure within the industry. As we move into the twenty-first century, diversity and inclusion has been discussed globally. This shift can differentiate the board decision on financial strategy in terms of capital structure. Hence, the motivation behind this research is to investigate the moderating role of women on board towards the relationship of corporate governance and capital structure. Data is collected from annual report of 24 listed energy firms in Bursa Malaysia over the period of 2015 to 2019. As a result, to determine the research objectives, this study employs descriptive statistical analysis, correlation coefficient, and random effects regression models. Moreover, the Generalized Method of Moments (GMM) estimate is used for robustness, and the results obtained differed from the random effect models. According to the findings of this study, board size and the proportion of women on boards of directors have a negative and substantial link with capital structure in terms of leverage level. Meanwhile, there is a positive and significant association between CEO duality and firm leverage, but no relationship exists between board independence and leverage. Additionally, when there is a large proportion of female directors on the board, the influence of board size on the firm's leverage level is beneficial.

Corporate Governance, Capital Structure and Moderating Effect of Women on Board of Directors in Malaysia's Energy Firm

The purpose of this study is to examine the effect of COVID-19 on stock market performance from the aspects of stock price volatility and stock market risk in the top GDP10 Asian countries. The dependent variable has been used in this study, which is the stock price volatility and stock market risk, while the independent variable that has been involved in this research is confirmed cases and death cases from COVID-19. In addition, the control variables that will be taken into this study are gross domestic product (GDP) and exchange rate. The study is examined between January 1, 2020 and June 30, 2020. Data were all collected from the source Investing.com, Trading Economies, Worldometer and World Bank. The findings show a significant positive relationship between the impacts of Covid-19 confirmed cases on stock price volatility among the top 10 Asian Country. However, there is an insignificant relationship between the impacts of Covid-19 death cases on stock price volatility among the top 10 GDP Asian Country. Covid-19 confirmed cases and death cases are insignificant on stock market risks among the top 10 GDP Asian Country.

The impact of covid-19 on stock market performance: evidence from ten asian countries

This research aims to investigate the moderating effect of information-seeking on the positive relationship between loan inclusion and Fintech P2P lending. It exploits how information-seeking plays an important role in the Fintech P2P loan decision. Unlike previous studies, we use primary data from 281 Fintech P2P borrowers to test the hypotheses. We use robust OLS regression and two-stage least square to estimate our model, and reveal three essential findings. First, loan inclusive (the individuals with traditional loan access) has lower Fintech P2P credit than the loan exclusive (those without traditional loan access). Second, information-seeking behavior would lower the Fintech P2P credit ratio. Lastly, information-seeking significantly moderates the relationship between loan inclusion and loans from Fintech P2P lending. It implies that those loan-exclusive individuals would have less Fintech P2P credit if they have high information-seeking. 

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Joseph Yau

Papers

Simultaneous development of velocity and temperature profiles for laminar flow of a non-Newtonian fluid in the entrance region of flat ducts

Pushing a balloon: does corporate risk disclosure matter for investment efficiency?

Corporate Governance, Capital Structure and Moderating Effect of Women on Board of Directors in Malaysia's Energy Firm

The impact of covid-19 on stock market performance: evidence from ten asian countries

Does information seeking moderate the relationship between financial loan inclusion and Fintech P2P lending?