A review on the application of the nanofluids

Nanofluid has become popular with the advancement in nanotechnology. Nanofluid has comparatively better stability than the microfluid because here much smaller-sized particles (nanometer size) are suspended in the base fluid. It has improved thermophysical properties and convective heat transfer coefficient than the base fluid alone. That is why researchers have implemented this novel heat transfer fluid in versatile fields. These are solar collectors, solar thermal energy storage, electronics cooling, cooling and heating, heat pipes, automobile radiator, refrigeration system, natural convection, quenching, and many other applications. These varied applications indicate that in imminent future nanofluid will play a major role in these fields. Though all these trials are at present at academic research level, however, with the advancement in nanotechnology, surface science, colloidal chemistry, and so forth this nanofluid will definitely play a major role in heat transfer in the coming days.     

Nanofluid in the multiphase flow field and heat transfer: A review

Two-phase heat transfer is widely used in the heat transfer field, for example, condenser and evaporator in the refrigeration system, riser, and condenser in thermal power plants, and so on. The advantage of two-phase heat transfer is that it gives a very-high convective heat transfer coefficient compared to other modes of heat transfer. Nanofluid is a comparatively new heat transfer fluid and very popular because of its improved thermophysical properties. If nanofluid is used in a two-phase heat transfer field, then the convective heat transfer coefficient may improve further. Nanofluids are possibly useful in many studies in two-phase heat transfer like pool boiling heat transfer, flow boiling heat transfer, nanofluids in a microchannel, forced convective heat transfer, condensation, spray cooling, enhanced oil recovery, and so on. The effect of nanoparticles on wettability, contact angle, and nucleation sites are also reviewed in this paper. Numerical studies in two-phase heat transfer are also reviewed and summarized in this paper. In this review, the chronological development of heat transfer in the two-phase field is provided in a tabular form. This table covers a wide period starting Before Common Era ages until the recent addition of nanoparticles in the two-phase heat transfer fluid.     

A technique to improve the linearization of frequency–voltage characteristic of LC-VCO

This paper presents a very low-power linearization technique to improve the linearity of frequency-voltage characteristic of LC-VCO (voltage controlled oscillator) using MOS varactor. This reduces the VCO gain (K _VCO) variation and its required value over the tuning voltage range. Low K _VCO improves noise and reference spur performances at the output of phase lock loop/frequency synthesizer (FS). Low K _VCO variation reduces FS loop stability problem. Using this VCO circuit, a fully on-chip integer-N frequency synthesizer has been fabricated in 0.18 μm epi-digital CMOS technology for 2.45 GHz ZigBee application. The measured VCO phase noise is ?115.76 and ?125.23 dBc/Hz at 1 and 3 MHz offset frequencies, respectively from 2.445 GHz carrier and the reference spur of the frequency synthesizer is ?68.62 dBc. The used supply voltage is 1.5 V.     

mTrust: Call Behavioral Trust Predictive Analytics Using Unsupervised Learning in Mobile Cloud Computing

Filtering spam voice calls are a still major challenge in today’s technology contrary to SMS or email-based spamming. A numerical measure of the trust between users can help us filter calls based on relevance. Given the abundance of user-generated information available from the huge number of online devices, we can harness the power of this data to develop software adapting to user behavior. Existing research works for trust computation face various challenges when it comes to global applicability and understandability of trust values. Our investigation includes detailed surveillance of user call patterns based on the call data available from mobile devices and proposes a novel approach to filter calls that are of higher relevance to users based on their call-trust values. Our implementation realizes the diversity in call patterns of different people due to varying usage and uses classification and clustering algorithms to generate personalized, accurate numerical, and categorical trust values for every user. Categorical trust makes it easier to apply and understand trust ratings on a global scale. The implementation also incorporates a cloud facility to crowd-source trust values from multiple users, in a single database to generate the global trust of a user which can be used for spam filtering on a global scale. A software named “mTrust” is developed in this work for the future generation of a trustworthy mobile cloud network.

     

An efficient low vision plant leaf shape identification system for smart phones

Multimedia Tools and Applications - In computer vision research, the first most important step is to represent the captured object into some mathematical transformed feature vector describing the...     

Metallurgical Failure Analysis of Drum Arching Tube of a 140 MW Thermal Power Plant

This investigation was conducted to examine the probable cause of failure of a drum arching tube at a 140 MW thermal power plant. Preliminary macroscopic examinations along with visual examination, optical microscopy, dimensional measurement, chemical analysis, hardness evaluation, thickness measurement to evaluate extent of damage were carried out to determine the probable cause/causes of failure. It was concluded that the combined effect of corrosion gouging and hydrogen damage were responsible for the failure. Appropriate remedial measures for avoiding such future failures are also recommended.     

Occurrence of Arsenic-contaminatedGroundwater in Alluvial Aquifers from Delta Plains,Eastern India: Options for Safe Drinking Water Supply

Arsenic contamination in groundwater used for drinking purposes has been envisaged as a problem of global concern. Exploitation of groundwater contaminated with arsenic within the delta plains in West Bengal has caused adverse health effects among the population within a span of 8-10 years. The sources of arsenic in natural water are a function of the local geology, hydrology and geochemical characteristics of the aquifers. The retention and mobility of different arsenic species are sensitive to varying redox conditions. The delta plains in West Bengal are characterized by a series of meander belts formed by the fluvial processes comprising different cycles of complete or truncated fining upward sequences (sand-silt-clay). The arseniferous groundwater belts are mainly located in the upper delta plain and in abandoned meander channels. Mineralogical investigations have established that arsenic in the silty clay as well as in the sandy layers occurs as coatings on mineral grains. Clayey sediments intercalated with sandy aquifers at depths between 20 and 80 m are reported as a major source of arsenic in groundwater.Integrated knowledge on geological, hydrologicaland geochemical characteristics of the multi-level aquifer system of the upper delta plain is therefore necessary in predicting the origin, occurrence and mobility of arsenic in groundwater in West Bengal. This would also provide a basis for developing suitable low-cost techniques for safe drinking water supply in the region.