Heat transfer characteristics of nanofluids: a review

Nanofluids are potential heat transfer fluids with enhanced thermophysical properties and heat transfer performance can be applied in many devices for better performances (i.e. energy, heat transfer and other performances). In this paper, a comprehensive literature on the applications and challenges of nanofluids have been compiled and reviewed. Latest up to date literatures on the applications and challenges in terms of PhD and Master thesis, journal articles, conference proceedings, reports and web materials have been reviewed and reported. Recent researches have indicated that substitution of conventional coolants by nanofluids appears promising. Specific application of nanofluids in engine cooling, solar water heating, cooling of electronics, cooling of transformer oil, improving diesel generator efficiency, cooling of heat exchanging devices, improving heat transfer efficiency of chillers, domestic refrigerator-freezers, cooling in machining, in nuclear reactor and defense and space have been reviewed and presented. Authors also critically analyzed some of the applications and identified research gaps for further research. Moreover, challenges and future directions of applications of nanofluids have been reviewed and presented in this paper. Based on results available in the literatures, it has been found nanofluids have a much higher and strongly temperature-dependent thermal conductivity at very low particle concentrations than conventional fluids. This can be considered as one of the key parameters for enhanced performances for many of the applications of nanofluids. Because of its superior thermal performances, latest up to date literatures on this property have been summarized and presented in this paper as well. However, few barriers and challenges that have been identified in this review must be addressed carefully before it can be fully implemented in the industrial applications.

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A review on applications and challenges of nanofluids

Suspended nanoparticles in conventional fluids, called nanofluids, have been the subject of intensive study worldwide since pioneering researchers recently discovered the anomalous thermal behavior of these fluids. The enhanced thermal conductivity of these fluids with small-particle concentration was surprising and could not be explained by existing theories. Micrometer-sized particle-fluid suspensions exhibit no such dramatic enhancement. This difference has led to studies of other modes of heat transfer and efforts to develop a comprehensive theory. This article presents an exhaustive review of these studies and suggests a direction for future developments. The review and suggestions could be useful because the literature in this area is spread over a wide range of disciplines, including heat transfer, material science, physics, chemical engineering and synthetic chemistry.

https://www.tandfonline.com/doi/pdf/10.1080/01457630600904593

Heat Transfer in Nanofluids—A Review

A review of nanofluid stability properties and characterization in stationary conditions

A colloidal mixture of nano-sized particles in a base fluid, called nanofluids, tremendously enhances the heat transfer characteristics of the original fluid, and is ideally suited for practical applications due to its marvelous characteristics. This article addresses the unique features of nanofluids, such as enhancement of heat transfer, improvement in thermal conductivity, increase in surface volume ratio, Brownian motion, thermophoresis, etc. In addition, the article summarizes the recent research in experimental and theoretical studies on forced and free convective heat transfer in nanofluids, their thermo-physical properties and their applications, and identifies the challenges and opportunities for future research.

Enhancement of heat transfer using nanofluids—An overview

Investigation on characteristics of thermal conductivity enhancement of nanofluids

Influence of glycerol on production and structural-physical properties of cellulose from Acetobacter sp. V6 cultured in shake flasks.

Bacillus pumilis F3-4 utilized feather as a sole source of carbon, nitrogen and sulfur. Supplementation of the feather medium with glucose or MgSO4 · 7H2O increased keratinolytic protease production (14.6–16.7 U/mg). The synthesis of keratinolytic protease was repressed by an exogenous nitrogen source. Keratinolytic protease was produced in the absence of feather (9.4 U/mg). Feather degradation resulted in sulfhydryl group formation (0.8–2.6 μM). B. pumilis F3-4 effectively degraded chicken feather (75%), duck feather (81%) and feather meal (97%), whereas human nails, human hair and sheep wool under went less degradation (9–15%).

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Nutritional regulation of keratinolytic activity in Bacillus pumilis.

The fruits of Zanthoxylum piperitum are known as having various physiology vitality, and the abstraction ingredient of the pericarp is also known as having strong antibiotic activities against various bacteria. Therefore, this study was carried out to estimate the effect of physiology vitality when the abstraction ingredient of Z. piperitum was added in soy sauce(Chopi-kanjang) and soybean paste(Chopi-doenjang). For the antibiotic activity against the pathogens of sitotoxism such as Staphylococcus aureus, Salmonella typhimurium, Vibrio parahemolyticus, Escherichia coli 0157:H7, the extracts of the Chopi-kanjang was added 1%, 2%, 4% pericarp of Z. piperitum in the manufacturing process of soy source. According to the results, the growth of E. coli 0157:H7 and V. parahemolyticus were respectively inhibited as 70% and 50% by the Chopi-kanjang added 2% of the ingredient. For the antibiotic effects of the aforementioned Chopi-kanjang against Sal. typhimurium and Sta. aureus, the growth of those pathogens was also inhibited between 40% and 60% according to the manufacturing period of Chopi-kanjang. It was confirmed that the antibiotic activity using the mixture of the abstraction ingredient and Chopi-doenjang was lower than those of Chopi-kanjang. In order to estimate the anticancer activity using by caspase-3 activity, the mixture of the abstraction ingredient of the pericarp of Z. piperitum and Chopi-kanjang was treated to leukemia cells. According to the results, the activities of caspase-3 using the mixture added 1%, 2% and 4% of the abstraction ingredient were respectively increased as much as 4, 12, 15 times comparing with the control which was treated with the soy source only. It could be that the mixture of the abstraction ingredient of the pericarp of Z. piperitum and soy source induced apoptosis, and the mixture of the abstraction ingredient and soybean paste had no effect on the activity of caspase-3. In order to find out the death of the aforementioned cells caused by necrosis or apoptosis, DNA fragmentation in the cell was examined. U-937 cells showed apoptotic DNA fragmentation in the incubation with Chopi-kanjang extract.

/pdf/antimicrobial-and-anticancer-activity-of-korean-traditional-2f33ophc7p.pdf

Antimicrobial and Anticancer Activity of Korean Traditional Soy Sauce and Paste with Chopi

To develop multifunctional microbial inoculant, microorganisms with antagonistic activity and biofertilizing activity were screened. Pantoea agglomerans and Bacillus megaterium from our laboratory culture collection, and strain MF12 from soil near poultry farm in Miryang were selected. On the basis of morphological, physiological studies and 16S rDNA sequence analysis, isolate MF12 was identified as the Bacillus pumilis. Three strains were studied for insoluble phosphate solubilization, indole-3-acetic acid (IAA) and siderophore production, ammonification ability, hydrolytic enzyme production and antifungal activity against phytopathogenic fungi. P. agglomerans did not produce any visible clear zone on agar plate containing 0.5% as a sole phosphorus source. However, this strain could solubilize insoluble phosphate in liquid medium. All strains produced IAA ranged from depending on culture time and had ammonification ability. Among three strains, only P. agglomerans produced siderophore. P. agglomerans produced pectinase and lipase, B. megaterium produced amylase, protease and lipase while B. pumilis produced protease and lipase. P. agglomerans showed antifungal activities against phytopathogenic fungi, Fusarium oxysporum and Colletotrichum gloeosporioides. B. pumilis showed antifungal activities against Botrytis cinerea, Sclerotinia sclerotiorum and Phythium ultimum.

Hyean-Cheal Park

Papers

Investigation on characteristics of thermal conductivity enhancement of nanofluids

Influence of glycerol on production and structural-physical properties of cellulose from Acetobacter sp. V6 cultured in shake flasks.

Nutritional regulation of keratinolytic activity in Bacillus pumilis.

Antimicrobial and Anticancer Activity of Korean Traditional Soy Sauce and Paste with Chopi

Isolation and Characteristics of Bacteria Showing Biocontrol and Biofertilizing Activities