Turbulent temperature profile in the quasi-fully developed region of a micro-tube

Turbulent temperature profiles in the quasi-fully developed region of a micro-tube were obtained numerically by solving the energy equation including the substantial derivative of pressure and viscous dissipation terms for the case of constant wall temperature. The fluid was assumed to be an ideal gas with constant density over the cross-section. The turbulent velocity profile was approximated by the three-layer model of Von Kármán. The temperature profiles were compared with the laminar flow and previous numerical solutions. The total temperature was higher than the wall temperature depending on the Mach number. The static temperature in the quasi-fully developed region agrees well with the temperature results for an ideal gas flow obtained by solving the Navier-Stokes and energy equations

Flow Characteristics of Fully Wetted Binary Solid Mixtures in Gas Fluidized Beds with Inclined Gas Distributors

A unique gas-fluidized bed in which fluidization is enhanced by adding a little water has potential for soft abrasive washing of various products. Preliminary experiments were carried out for the washing of farm products. Gas fluidized beds of binary solids mixtures with inclined gas distributors provide hydrodynamic and mixing data assisting the design of dry and wet gas-fluidized beds

Experiments on measurement of heat transfer rate of gas flow through microchannel with constant wall temperature

Experimental results for the measurement of heat transfer rates in microchannel gas flow are crucial for gas to gas micro heat exchangers. A critical overview of the main factors that play an important role in the determination of heat transfer rate is presented. The experimental and numerical data obtained from authors' previous studies are used in order to highlight the characteristics of convective heat transfer of gas through microchannels with constant wall temperature. It is suggested to obtain heat transfer rates by determining the difference between the gas enthalpy at the inlet and outlet by measuring local temperature and pressure. The heat transfer rates obtained in the present study were compared with those determined by the difference in total temperatures and incompressible flow Nusselt number

Green synthesis of gold nanoparticles based on plant extract for nanofluid-based hybrid photovoltaic system application

Green synthesis technique has overcome the limitation of chemical and physical methods including cost, usage of toxic chemicals and hazardous by-products. Gold nanoparticles (Au-NPs) synthesized using green synthesis method have received great interest due to the physicochemical characteristics and their application in various fields. This review paper has reviewed the capability of various parts of the plant in order to act as green reducing agent to cap gold source to Au-NPs. This includes the root/rhizomes, bark, leaves, flowers, fruits and fruits peel. All previous works have successfully synthesized Au-NPs in nano-range and even with smaller size up to ~10 nm. Finally, this review paper has review current progress of nanofluid-based hybrid photovoltaic-system that used Au-NPs in the nanofluid due to their high surface plasmon resonance

Uncertainty of temperature measured by thermocouple

Reliability of data is important for researchers to verify their research result. For temperature measurement involving thermocouple, uncertainty needs to be determined before deciding the reliability of data. In this research, four error sources were proposed to have contributed in the uncertainty of temperature measured by a thermocouple which were resolution limit of data acquisition device, error in temperature measurement based on voltage measurement, reference junction compensation error and data fluctuation. Experiments were carried out to obtain reference junction compensation error and data fluctuation using HIOKI data logger (LR8400-20). The procedure to obtain the uncertainty of the measured temperature including the reference junction compensation uncertainty is proposed. The uncertainty was obtained by combining all the error values with root-sum-square equation. The uncertainty for K thermocouple obtained from this research was 0.42 °C

Characterization of Crude Palm Oil (CPO), corn oil and waste cooking oil for biodiesel production

Biodiesel production is the reaction of raw oils with mixing and heating within catalyst and methanol. The raw oils usually come from vegetable oils and animal fats. Vegetable oils are a promising feedstock for biodiesel production since they are renewable in nature. Nevertheless, the physical properties of biodiesel pose some acute problems when used in an unmodified engine. It is important to diesel and biodiesels because it impacts components such as the fuel pump. Therefore, this paper intends to investigate the properties of biodiesel samples in terms of viscosity, density, flash point and acid values at different bio lipids and different mixing time. The evaluation is carried out on the three types of biodiesels: CPO, corn oil, and waste cooking oil. Methanol was chosen over the others for the transesterification process because it was cheaper. The esterification process, which reduces the amount of free fatty acids in the crude oil, will be performed with the help of an acid catalyst. Alkaline catalysts, in contrast, are used for the transesterification process. The comparison of all the samples shows that CPO is the better biodiesel than the other due to the physical properties of kinematic viscosity, density and flashpoint

Fire resistance rating for gypsum and kapok fiber composite materials

Fire rated door is one of the passive fire protection systems that can prevent fire and smoke from spreading when a fire occurs. The purpose of this study was to analyze fire rated doors made of Gypsum and Kapok fiber composites. This fire rated door has been manufactured in accordance with Malaysian Standard MS1073: Part 2: 1996. This fire rated door has been modified with various composite compositions and thicknesses. The results showed that the fire rated door made of Gypsum and Kapok fiber can last from 30 to 60 minutes. This study clearly shows that door thickness is very important in the manufacture of fire rated door

A comprehensive review of the influences of nanoparticles as a fuel additive in an internal combustion engine (ICE)

Nanofluid is a colloidal mixture consisting of nano-sized particles dispersed in a liquid medium. It improves heat transfer properties and promotes high energy efficiency in a wide spectrum of engineering applications. In recent years, particularly in the automotive industry, the addition of nanofluid in diesel/biodiesel as an additive for ICE has become an attractive approach to promote enhanced combustion efficiency and emission reduction due to their superior thermophysical properties. Many researchers have previously demonstrated that the addition of nanoparticles in diesel/biodiesel fuel improved the overall engine combustion characteristics. As a whole, this study aims to summarize the recent research findings related to the effect of nanoparticles on the fuel properties and engine combustion efficiency. Furthermore, different types of additive blended with varying fuel properties are also compared and discussed. Lastly, the advantages and prospects of using nanofluid as an additive fuel are summarized for future research opportunities

Role of serine 249 of ezrin in the regulation of sodium-dependent phosphate transporter NaPi-IIa activity in renal proximal tubular cells

Type IIa sodium-dependent phosphate transporter (NaPi-IIa) is responsible for renal phosphate reabsorption and maintenance of systemic phosphate homeostasis in mammals. Macromolecular complex formation of NaPi-IIa with sodium-proton exchanger related factor-1 (NHERF-1) and ezrin is important for apical membrane localization in the proximal tubular cells. Here, we investigated the interactions of the ezrin phosphomimetic mutation of serine to aspartic acid at 249 with NHERF-1 and the inhibition of apical membrane localization of NaPi-IIa. In vitro phosphorylation analysis revealed that serine 249 of human ezrin serves as a phosphorylation site for protein kinase A. The Nterminal half of ezrin had a dominant negative effect on the phosphate transport activity and inhibited the apical localization of NaPi-IIa in renal proximal tubular cells. We found that the phosphomimetic S249D mutant interfered with the inhibitory effects of the dominant negative mutant on the transport and localization of NaPi-IIa. The S249D mutant also inhibited the interaction with NHERF-1. Therefore, serine 249 of ezrin can play important roles in the regulation of the complex formation and membrane localization of NaPi-IIa