A novel two-level secure access control approach for blockchain platform in healthcare

International Journal of Information Security - The advent of blockchain technology has ushered a paradigm shift in storage of healthcare data from conventional to online mode. As public ledgers,...     

Study of combined effect of natural convection and radiation heat transfer from annular finned vertical cylinder

The present numerical study reports the combined effect of natural convection and radiation heat from a vertical cylinder with annular fins. The study involves simulation for laminar as well as turbulent regimes. For the present study, Rayleigh's number is varied in the range ${10}^8-{10}^{12}$, emissivity in the range $0.2-0.8$, and the fin spacing ratio (s/d) in the range $0.1-10$. The radiation heat transfer has been found to share a considerable amount in the total heat transfer of the system for the laminar regime, but in the turbulent regime, its effect is minimal and can be neglected. When the fin spacing ratio is reduced, the total heat transfer increases for both the turbulent and laminar flow conditions. But the radiation heat increases with a reduction in fin spacing ratio for laminar and in case of turbulent flow radiation heat rate reduces with a reduction in s/d ratio. For the range of Rayleigh numbers considered in the present study, the Nusselt number increases with the increment of the fin spacing ratio. Thus, it can be concluded that there is a remarkable enhancement in the heat transfer rate in laminar cases with the fins. For turbulent cases, the fin efficiency lies between 40% and 50%.     

Some studies on glass fiber-reinforced polypropylene. Part I: Reduction in fiber length during processing

The reduction in fiber length during extrusion and injection molding of two commercial glass fiber-reinforced polypropylene products containing 30 percent by weight of glass fibers was studied. The first product had very small fibers of average length around 0.5 mm and also contained a coupling agent. The second product contained relatively longer glass fibers of 9 mm length and no coupling agent. In both cases, fiber attrition occurs predominantly at the solid-melt interface in the meiting zone of the extruder. However, in the short fiber granules, the maximum of the length distribution, which for the initial sample is around 0.5 mm, moved to shorter fiber lengths along the screw channels further from the hopper. In the long fiber granules, a bimodal length distribution was obtained in the intermediate channels; the first maximum was around the original length of 9 mm and the second centered around 0.5 mm. Thus, the forces at the solid-melt interface result in fiber breakage to lengths which are predominantly around 0.5 mm. The fiber attrition was observed to be more severe in injection molding apparently because of higher shear rates and also because the fibers had to pass through narrow channels. The measured distributions of fiber length along the screw channels for the two products are presented, and the possible mechanisms of fiber breakage are discussed. The mechanical properties of samples containing different fiber length distributions and the effects of fiber length and interfacial adhesion on properties are presented and discussed in Part II.     

Boron Induced Crystallization of Silicon on Glass: an Alternate Way to Crystallize Amorphous Silicon Films for Solar Cells

Silicon - Demand for efficient window layer in thin film solar cells with high crystallinity is ever increasing that finds important application in multi-junction/tandem silicon solar cells. Doping...     

Power Optimized Multiple-UAV Error-Free Network in Cognitive Environment

Many extensive UAV communication networks have used UAV cooperative control. Wireless networking services can be offered using unmanned aerial vehicles (UAVs) as aerial base stations. Not only is coverage maximization, but also better connectivity, a fundamental design challenge that must be solved. The number of applications for unmanned aerial vehicles (UAVs) operating in unlicensed bands is fast expanding as the Internet of Things (IoT) develops. Those bands, however, have become overcrowded as the number of systems that use them grows. Cognitive Radio (CR) and spectrum allocation approaches have emerged as a potential approach for resolving spectrum scarcity in wireless networks, and hence as technological solutions for future generations, from this perspective. As a result, combining CR with UAVs has the potential to give significant benefits for large-scale UAV deployment. The paper examines existing research on the subject of UAV covering and proposes a multi-UAV cognitive-based error-free model for energy-efficient communication. Coverage maximization, power control, and enhanced connection quality are the three steps of the proposed model. To satisfy the desired signal-to-noise ratio, the covering zone efficacy is investigated as a function of the distance among UAVs stationed in a specific geographic region depending on multiple deployment configurations like as rural, suburban, and urban macro deployment scenarios of the ITU-R M.2135 standard (SNR).     

Effects of Silicon and Organic Manure on Growth,Fruit Yield,and Quality of Grape Tomato Under Water-Deficit Stress

Silicon - Mitigation of deleterious effects of drought stress on the growth and productivity of agronomic and horticultural crops warrants urgent and sustainable actions. Soil application of...     

Extraction and Analysis of Recovered Silver and Silicon from Laboratory Grade Waste Solar Cells

Silicon - In the present work, a new process is reported to recover metallic contacts and wafer from the crystalline silicon solar cell through chemical etching. 2 M KOH was used as an...