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Record 1 of 11 |
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Authors: Singh, M; Verma, SK; Biswas, I; Mehta,
R |
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JOURNAL OF POLYMER ENGINEERING |
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Volume: 39 Issue: 1 Pages: 48-57 Published: JAN
2019 Language: English Document
type: Article |
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Abstract: Shear thickening fluids (STF) are stabilized and concentrated
colloidal suspensions of hard nano-particles in a
liquid medium (polymer) that, under the influence of impact forces, show
non-Newtonian fluid behavior (shear thickening)
dissipating the energy of impact. The viscosity of the dispersion medium
should be optimum to lead to an increase in shear thickening, and at the same
time, should also allow proper dispersion of the particles. Herein, an STF
based on 20 wt% fractal nano-fumed
silica particles of 11 nm suspended in a liquid medium of polyethylene glycol
(PEG 200) with different concentrations of silicone oil was prepared. These
systems were studied in terms of steady-state and dynamic-state rheological behavior under a wide range of temperature, shear rate,
strain rate and frequency. The STF with replacement of up to only 20% of PEG
with silicone oil as the liquid medium shows a large increase (about four
times) in shear thickening parameters when compared with STF containing only
PEG under the same processing conditions. It also shows more elastic behavior at high frequencies which are due to the high
cross-linking property of silicone oil, contributing to much-improved
properties, which are highly desirable from the view point of many
applications. |
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Record 2 of 11 |
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Thermal degradation kinetics of oxo-degradable PP/PLA blends |
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Authors: Mandal, DK; Bhunia, H; Bajpai, PK |
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JOURNAL OF POLYMER ENGINEERING |
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Volume: 39 Issue: 1 Pages: 58-67 Published: JAN
2019 Language: English Document
type: Article |
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Abstract: In this article, the influence of polylactide
and pro-oxidant on the thermal stability, degradation kinetics, and lifetime
of polypropylene has been investigated using thermogravimetric
analysis under nitrogen atmosphere at four different heating rates (i.e. 5,
10, 15, and 20 degrees C/min). The kinetic parameters of degradation were
studied over a temperature range of 30-550 degrees C. The derivative thermogravimetric curves have indicated single stage and
two stage degradation processes. The activation energy was evaluated by using
the Kissinger, Kim-Park, and Flynn Wall methods under the nitrogen
atmosphere. The activation energy value of polypropylene was much higher than
that of polylactide. Addition of polylactide and prooxidant in
polypropylene decreased the activation energy. The lifetime of polypropylene
has also decreased with the addition of polylactide
and pro-oxidant. |
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Record 3 of 11 |
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UAVs assisted queue scheduling in
ground ad hoc networks |
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Authors: Sharma, V; Kumar, R |
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INTERNATIONAL JOURNAL OF AD HOC AND UBIQUITOUS COMPUTING |
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Volume: 30 Issue: 1 Pages: 1-10 Published: 2019 Language: English Document
type: Article |
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Abstract: Hybrid networks provide a vast range of applications in areas of
military and civilian activities. One of the examples of hybrid network
formations is unmanned aerial vehicles (UAVs) assisted ground ad hoc
networks. Efficient coordination in these networks can resolve complex issues
such as coverage, proper connectivity, scalability, and QoS.
However, reliable data transmission with enhanced QoS
is one of the key challenges in these types of hybrid ad hoc formations. In
this paper, an efficient queue scheduling approach is proposed that allows
improved QoS to end users. The proposed queue
scheduling approach is developed in two parts. The first part utilises the
Quaternion based Kalman Filter to find the
appropriate locations for placement of each UAV. In the second part,
satisfied importance analysis (SIA) is used to find the governing rules for
the selection of appropriate queue for transmission. The effectiveness of the
proposed model is demonstrated using simulations. |
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Record 4 of 11 |
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Multimedia big data computing and
Internet of Things applications: A taxonomy and process model |
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Authors: Kumari, A; Tanwar,
S; Tyagi, S; Kumar, N; Maasberg,
M; Choo, KKR |
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JOURNAL OF NETWORK AND COMPUTER APPLICATIONS |
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Volume: 124 Pages: 169-195 Published: DEC
15 2018 Language: English Document
type: Review |
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Abstract: With an exponential increase in the provisioning of multimedia devices
over the Internet of Things (IoT), a significant
amount of multimedia data (also referred to as multimedia big data - MMBD) is
being generated. Current research and development activities focus on scalar
sensor data based IoT or general MMBD and overlook
the complexity of facilitating MMBD over loT. This
paper examines the unique nature and complexity of MMBD computing for loT applications and develops a comprehensive taxonomy
for MMBD abstracted into a novel process model reflecting MMBD over IoT. This process model addresses a number of research
challenges associated with MMBD, such as scalability, accessibility,
reliability, heterogeneity, and Quality of Service (QoS)
requirements. A case study is presented to demonstrate the process model. |
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Record 5 of 11 |
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A computational study of Stillinger-Weber silicon at 0.75 GPa
in supercooled region |
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Authors: Gautam, AK; Chandra, A |
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INTERNATIONAL JOURNAL OF MODERN PHYSICS B |
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Volume: 32 Issue: 30 Published: DEC
10 2018 Language: English Document
type: Article |
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Abstract: We studied the liquid-liquid transition in supercooled
silicon modeled by the Stillinger-Weber
potential. The Isothermal Isobaric Monte Carlo (NPT-MC) simulation techniques
were performed here to compute the free energy difference between the two
liquid phases of silicon by Bennett Acceptance Ratio (BAR) method along with
a reversible path at 0.75 GPa pressure and 970 K
temperature. The thermodynamic properties as energy (phi) and density (rho)
of the high-density liquid (HDL) phase have been computed here at different
temperatures from 970-990 K. We also computed the entropy difference between
the high-density liquid (HDL) and low-density liquid (LDL) phases which
indicates that the glass transition temperature for the LDL phase is lower
compared to the HDL phase. Further, by using the BAR method, we have computed
the excess Gibbs free energy (G(e)) of HDL phase with respect to the
crystalline phase at different temperatures in the supercooled
region of SW-Silicon potential model. Based on the slope of excess Gibbs free
energy with respect to temperature (T), we found that the excess entropy
(S-e) of the HDL with respect to crystalline phase shows a nonmonotonic dependence on temperature at the
liquid-liquid transition temperature of T-LL( )= 970
K. Our results are in good agreement with the previous observation of a nonmonotonic dependence of the enthalpy on temperature in
MD simulations, starting with the HDL phase at a temperature just above T-LL.
All these properties are useful to understand the phase behavior
of supercooled silicon and can be applicable to
identify the better quality of silicon for industrial uses. |
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Record 6 of 11 |
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Authors: Prashu; Nandkeolyar,
R |
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RESULTS IN PHYSICS |
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Volume: 11 Pages: 966-974 Published: DEC
2018 Language: English Document
type: Article |
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Abstract: The study of the unsteady magnetohydrodynamic
three-dimensional radiative flow of a viscous incompressible electrically
conducting Casson liquid along a stretching surface
including the effects of Hall current is presented in this article. The fluid
flow model consists of time-dependent partial differential equations which
are highly non-linear. Similarity transformations are utilized to obtain
ordinary differential equations in similarity form. Further, a numerical
approach, namely spectral quasilinearization method
(SQLM), is used to solve resulting highly nonlinear ordinary differential
equations. A detailed analysis is carried out to study the influences of
significant parameters, such as Casson liquid
parameter, Hall current parameter, magnetic parameter, unsteadiness
parameter, radiative parameter, on the profiles' of the velocity field and
temperature field. The behavior of emerging
quantities of engineering interest such as skin friction coefficient and the Nusselt number is also studied. Fluid flow model as
presented in the paper finds applications in silicon suspensions, blood flow,
polymer engineering, and printing industry. |
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Record 7 of 11 |
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Photocatalytic study of ZnS-Ag2S
nanocomposites-effect of thioglycerol |
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Authors: Kaur, J; Gupta, A; Pandey, OP |
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SOLAR ENERGY |
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Volume: 176 Pages: 678-687 Published: DEC
2018 Language: English Document
type: Article |
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Abstract: Nanocomposites (NCs) of different band gap semiconductors provide
better photocatalytic activity as compared to that of monolithic
semiconductor nanoparticles (NPs). With the aim to investigate the effect of
organic capping agent (thioglycerol; TG in the present
study) on photocatalytic activity, ZnS-Ag2S NCs have been synthesized in the
presence of TG using simple chemical precipitation route. For comparative
studies, NCs have been synthesized under same synthesis conditions without
TG. Structural studies were done using X-Ray diffraction (XRD) technique.
Morphological features of as prepared samples were recorded by high
resolution transmission electron microscopy (HRTEM). UV-Vis and
photoluminescence studies were carried out to study the optical properties of
synthesized samples. Photocatalytic studies of as-synthesized NCs have been
carried out by selecting crystal violet (CV) as a model organic pollutant. It
is observed that NCs (synthesized in absence of TG) exhibit better
photocatalytic activity as compared to the TG capped NCs. The results of the
present study may helpful in practical application of these composites in the
area of photocatalysis and other related optical
applications. |
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Record 8 of 11 |
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Performance prediction of PV
module using electrical equivalent model and artificial neural network |
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Authors: Mittal, M; Bora, B; Saxena, S; Gaur,
AM |
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SOLAR ENERGY |
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Volume: 176 Pages: 104-117 Published: DEC
2018 Language: English Document
type: Article |
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Abstract: Before a photovoltaic (PV) system is installed, a prerequisite
modelling and performance analysis are carried out which estimates the
performance parameters and reliability in operation of PV system. This paper
proposes a neural network approach to performance prediction of PV Modules.
Here the feed forward neural networks are used to predict I-V curve
parameters as a function on input irradiance and temperature. K Fold
cross-validation is used to validate model accuracy for determination of I-V
curve parameters for five different technology modules, i.e., CdTe, CIGS, MICROMORPH, MUTICRYSTALLINE, MAXEON. A
comparison is also drawn between the neural network predictor and the
existing modeling procedures available. Model
parameters have been determined following iterative, analytical and
regression of known data points for seven and five parameter model of PV
Modules. Among the electrical equivalent models, the seven parameter model is
the most efficient model for performance prediction however commutation of model
parameters in complex and tedious. Neural network model simplifies the
computational process at the expense of higher error variance in comparison
to electrical equivalent models. Further, a cascade implementation of the
above two is designed and tested on Multicrystalline
and Maxeon technology modules for higher model
accuracy. The results obtained, verify the proposed cascaded model to be the
most efficient model in comparison to independent models where mean bias
error deviations are less than +/- 1% and error variance is reduced
significantly. Also, a MATLAB based graphical user interface (GUI) is
developed that can be used to predict the performance based on the analysis
carried out. The proposed model is tested against a set of operating conditions
and compared to the actual experimental values obtained using outdoor tests. |
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Record 9 of 11 |
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Crosslinked polymer doped binary coatings for corrosion protection |
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Authors: Kaur, H; Sharma, J; Jindal, D; Arya, RK; Ahuja, SK; Arya, SB |
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PROGRESS IN ORGANIC COATINGS |
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Volume: 125 Pages: 32-39 Published: DEC
2018 Language: English Document
type: Article |
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Abstract: Solvent-based polymeric multilayer coatings prepared by ex-situ
addition of crosslinked poly(styrene-co-divinyl benzene) in poly(styrene)-ethylbenzene solution
were examined for corrosion protection of mild steel in a simulated water
environment equivalent to sea water and acid rain. Electrochemical impedance
spectroscopy (EIS) technique was used to determine the corrosion resistance behavior of the prepared polymeric coatings in 3.5 wt% of NaCl aqueous solution.
EIS analysis suggested that the sample solution prepared by adding 1% crosslinked polymer in poly(styrene)-ethylbenzene
solution, has better corrosion resistance as compared to the sample solutions
prepared by adding 3% and 2% of crosslinked polymer
in poly(styrene)-ethylbenzene solutions. Scanning electron microscopy (SEM)
revealed that substrate coated with polymeric solution prepared by adding 1%
of crosslinked polymer in poly(styrene)-ethyl
benzene solution showed less corrosion as compared to the substrates coated
with sample solutions prepared by adding 3% and 2% of crosslinked
polymer in poly(styrene)-ethylbenzene solutions. |
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Record 10 of 11 |
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Surfactant enhanced drying of waterbased poly(vinyl alcohol) coatings |
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Authors: Sharma, D; Sharma, J; Arya, RK; Ahuja, S; Agnihotri,
S |
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PROGRESS IN ORGANIC COATINGS |
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Volume: 125 Pages: 443-452 Published: DEC
2018 Language: English Document
type: Article |
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Abstract: Coatings of the poly(vinyl alcohol)-water
based system have been studied. The effect of various surfactants on drying beavior was investigated. Anionic (SDS), non- ionic (PEG)
and fluoro based surfactants (CAPSTONE FS-63) were
used to minimize the residual solvent. The results indicate that the anionic
surfactant is not much effective in drying of these coatings whereas the
non-ionic surfactant changed the drying behavior to
a small extent. The fluro based surfactant showed
the significant effect on drying behavior of the
coatings. The drying rate in the fluoro based
surfactant was moderate for a longer time which led to more solvent recovery.
Solutions with high polymer concentrations need high amount of surfactant for
significant change in the drying behavior. |
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Record 11 of 11 |
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Authors: Singh, HS; Kalraiya, S |
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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED
ENGINEERING |
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Volume: 28 Issue: 9 Published: NOV
2018 Language: English Document
type: Article |
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DOI: 10.1002/mmce.21432 |
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Abstract: In this manuscript, a compact UWB with dual band-notched planar
monopole antenna is investigated. The band notched characteristics at WiMAX
and WLAN is obtained by connecting two pairs of stubs to the modified ground
plane. The size of proposed antenna is 25(W) x 30(L) x 1.6(H) mm(3) which consists of a fork shaped structure as a main
radiating element and excited with a 50-omega microstrip
line. The proposed antenna covers Bluetooth frequency band (2.4-2.48 GHz)
along with UWB spectrum without increasing the size of the antenna. The
measured operating frequency of the proposed antenna is from 2.4 to 12.8 GHz
along with WiMAX and WLAN band-notched. Moreover, the measured gain of the
proposed antenna varies between 2 and 6 dBi except
notched band. At notched frequencies, it is -1 and -6 dBi
at WiMAX and WLAN, respectively. The total antenna efficiency varies from 80%
to 95% except notched frequency bands. The radiation patterns and time domain
characteristics are also analyzed and found
suitable for the modern UWB applications. Finally, a prototype of dual
band-notched antenna is manufactured and its characteristics are measured
using network analyzer. The simulated and measured
results are found in close agreement. |