Thermal analysis of a nanofluid free jet impingement on a rotating disk using volume of fluid in combination with discrete modelling

The objective of this research is to analyse the heat transfer characteristics of air/nanofluid jet cooling flow on a hot circular rotating disk and track the possible fate of nanoparticles. Computational methods are employed to initially solve the air and liquid multiphase flow in ANSYS Fluent 19.3 by considering the importance of surface tension between two phases through the volume of fluid model. Subsequently, the nanoparticles are injected through the nozzle into the jet liquid to calculate nanoparticles distribution via pre-defined user functions. The impacts of parameters such as nanoparticles volume fraction and disk rotation are evaluated. The patterns of the jet flow from inlet until steady-state condition shows that there exist six stages of fluid flow for a stationary hot disk, while splattering of droplets disappears when the disk starts rotating. In spite of the positive impact of nanoparticles for rotating disk, larger torque is required for higher nanofluid volume fraction to enhance heat transfer due to increase in viscosity. Also, the trend for heat transfer coefficient identifies five flow regions from the stagnation point to the edge of the rotating disk.The National Natural Science Foundation of Chinahttp://www.elsevier.com/locate/ijtshj2021Mechanical and Aeronautical Engineerin

Towards a new model of grit within a cognitive-affective framework of self-regulation

Grit – passion and perseverance for long-term goals – has been empirically shown to be a positive predictor of success across multiple contexts. The current study developed a new framework of grit within a framework of self-regulatory behaviours. Here, a qualitative approach was assumed to obtain interview data from chief innovation officers and chief information officers within technologically intensive industries. Empirical evidence was used to inductively determine the underlying cognitive-affective processing that influences gritty behaviour. Overall, six strategies were identified: temporal perspective, perpetual evaluation, motivational orientation, strength and resource gathering, system thinking and framing. Organisations may utilise the grit model developed here to enhance the grittiness of their innovation leaders by building effective cognitive-affective strategies

High variability of atmospheric mercury in the summertime boundary layer through the central Arctic Ocean

The biogeochemical cycles of mercury in the Arctic springtime have been intensively investigated due to mercury being rapidly removed from the atmosphere. However, the behavior of mercury in the Arctic summertime is still poorly understood. Here we report the characteristics of total gaseous mercury (TGM) concentrations through the central Arctic Ocean from July to September, 2012. The TGM concentrations varied considerably (from 0.15 ng/m3 to 4.58 ng/m3), and displayed a normal distribution with an average of 1.23 ± 0.61 ng/m3. The highest frequency range was 1.0–1.5 ng/m3, lower than previously reported background values in the Northern Hemisphere. Inhomogeneous distributions were observed over the Arctic Ocean due to the effect of sea ice melt and/or runoff. A lower level of TGM was found in July than in September, potentially because ocean emission was outweighed by chemical loss

Overview of China’s Antarctic research progress 1984–2016

It is more than 30 years since the first Chinese National Antarctic Research Expedition (CHINARE) landed in Antarctica in 1984, representing China’s initiation in polar research. This review briefly summarizes the Chinese Antarctic scientific research and output accomplished over the past 30 years. The developments and progress in Antarctic research and the enhancement of international scientific cooperation achieved through the implementation of the CHINARE program have been remarkable. Since the 1980s, four permanent Chinese Antarctic research stations have been established successively and 33 CHINAREs have been completed. The research results have been derived from a series of spatiotemporal observations in association with various projects and multidisciplinary studies in the fields of oceanography, glaciology, geology, geophysics, geochemistry, atmospheric science, upper atmospheric physics, Antarctic astronomy, biology and ecology, human medicine, polar environment observation, and polar engineering

5G Internet of Things: A survey

© 2018 The existing 4G networks have been widely used in the Internet of Things (IoT) and is continuously evolving to match the needs of the future Internet of Things (IoT) applications. The 5G networks are expected to massive expand today's IoT that can boost cellular operations, IoT security, and network challenges and driving the Internet future to the edge. The existing IoT solutions are facing a number of challenges such as large number of connection of nodes, security, and new standards. This paper reviews the current research state-of-the-art of 5G IoT, key enabling technologies, and main research trends and challenges in 5G IoT

A multi-targeted approach to suppress tumor-promoting inflammation

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes

Differential regulation of iron chelator-induced IL-8 synthesis via MAP kinase and NF-κB in immortalized and malignant oral keratinocytes

Abstract Background Interleukin-8 (IL-8) is a cytokine that plays an important role in tumor progression in a variety of cancer types; however, its regulation is not well understood in oral cancer cells. In the present study, we examined the expression and mechanism of IL-8 in which it is involved by treating immortalized (IHOK) and malignant human oral keratinocytes (HN12) cells with deferoxamine (DFO). Methods IL-8 production was measured by an enzyme-linked immunoabsorbent assay and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Electrophoretic mobility shift assays was used to determine NF-κB binding activity. Phosphorylation and degradation of the I-κB were analyized by Western blot. Results IHOK cells incubated with DFO showed increased expression of IL-8 mRNA, as well as higher release of the IL-8 protein. The up-regulation of DFO-induced IL-8 expression was higher in IHOK cells than in HN12 cells and was concentration-dependent. DFO acted additively with IL-1β to strongly up-regulate IL-8 in IHOK cells but not in HN12 cells. Accordingly, selective p38 and ERK1/2 inhibitors for both kinases abolished DFO-induced IL-8 expression in both IHOK and HN12 cells. Furthermore, DFO induced the degradation and phosphorylation of IκB, and activation of NF-κB. The IL-8 inducing effects of DFO were mediated by a nitric oxide donor (S-nitrosoglutathione), and by pyrrolidine dithiocarbamate, an inhibitor of NF-κB, as well as by wortmannin, which inhibits the phosphatidylinositol 3-kinase-dependent activation of NAD(P)H oxidase. Conclusion This results demonstrate that DFO-induced IL-8 acts via multiple signaling pathways in immortalized and malignant oral keratinocytes, and that the control of IL-8 may be an important target for immunotheraphy against human oral premalignant lesions.</p