1,121 research outputs found
Dynamics of Diblock Copolymers in Dilute Solutions
We consider the dynamics of freely translating and rotating diblock (A-B),
Gaussian copolymers, in dilute solutions. Using the multiple scattering
technique, we have computed the diffusion and the friction coefficients D_AB
and Zeta_AB, and the change Eta_AB in the viscosity of the solution as
functions of x = N_A/N and t = l_B/l_A, where N_A, N are the number of segments
of the A block and of the whole copolymer, respectively, and l_A, l_B are the
Kuhn lengths of the A and B blocks. Specific regimes that maximize the
efficiency of separation of copolymers with distinct "t" values, have been
identified.Comment: 20 pages Revtex, 7 eps figures, needs epsf.tex and amssymb.sty,
submitted to Macromolecule
A novel power optimized hybrid renewable energy system using neural computing and bee algorithm
With rapid depletion of non-renewable energy resources or the fossil fuels like coal, petroleum etc., there has been a significant shift in innovations towards exploiting and tapping of energy from renewable energy resources like sun, bio gas, wind etc., E Off late, there has been an increased research towards combined or hybrid integrated energy generation systems based on renewable resources like sun-wind, sun-biogas etc., These hybrid systems effectively address the past demerits observed in standalone systems which could provide substantial power only during specific periods and seasons. For example, solar power would be much reduced during the night time. Hence hybrid systems effectively counteract this issue as the lack of stability in one system is well compensated by the other. This research paper proposes an optimized hybrid PV-wind power generation system with optimization towards maximization of power generated from the system with the help of neural architecture and bee colony algorithm. The proposed system has been implemented and tested for a wide range of solar irradiances and wind velocities and maximum and stable power generation has been observed when compared to existing techniques
Polymers pushing Polymers: Polymer Mixtures in Thermodynamic Equilibrium with a Pore
We investigate polymer partitioning from polymer mixtures into nanometer size
cavities by formulating an equation of state for a binary polymer mixture
assuming that only one (smaller) of the two polymer components can penetrate
the cavity. Deriving the partitioning equilibrium equations and solving them
numerically allows us to introduce the concept of "polymers-pushing-polymers"
for the action of non-penetrating polymers on the partitioning of the
penetrating polymers. Polymer partitioning into a pore even within a very
simple model of a binary polymer mixture is shown to depend in a complicated
way on the composition of the polymer mixture and/or the pore-penetration
penalty. This can lead to enhanced as well as diminished partitioning, due to
two separate energy scales that we analyse in detail.Comment: 10 pages, 6 figure
Electronic structure of strongly correlated d-wave superconductors
We study the electronic structure of a strongly correlated d-wave
superconducting state. Combining a renormalized mean field theory with direct
calculation of matrix elements, we obtain explicit analytical results for the
nodal Fermi velocity, v_F, the Fermi wave vector, k_F, and the momentum
distribution, n_k, as a function of hole doping in a Gutzwiller projected
d-wave superconductor. We calculate the energy dispersion, E_k, and spectral
weight of the Gutzwiller-Bogoliubov quasiparticles, and find that the spectral
weight associated with the quasiparticle excitation at the antinodal point
shows a non monotonic behavior as a function of doping. Results are compared to
angle resolved photoemission spectroscopy (ARPES) of the high temperature
superconductors.Comment: final version, comparison to experiments added, 4+ pages, 4 figure
A study on Vertigo – Evaluation of Bedside Tests and Aetiopathology.
Vertigo is defined as the ‘hallucination’ of movement, either of self (subjective) or the
environment (objective).
Usually the patient uses various terms (eg.) Bouncing, Oscillating, Staggering,
Swimming, Twisting Rolling, Spinning, Rocking, Lightheadness, Imbalance, Floating,
Fainting, Falling.
For the most part they are benign but always there is the possibility that they signal the
presence of an important neurological disorder.
Diagnosis of the underlying disease demands that the complaint of vertigo be
analyzed correctly, the nature of the disturbance of function being determined first and
then its anatomic localization.
A careful history and physical examination usually affords the basis for separating true
vertigo from the dizziness of the anxious patient and from the other types of pseudo
vertigo
This study evaluates the vertigo patients based on history, examination and relevant
investigations to establish the etiology for the vertigo.
Benign paroxysmal positional vertigo (BPPV) was the commonest cause of vertigo in
this study.
31 to 40 years had the highest incidence of vertigo in this study.
Migranous vertigo was the common central cause of vertigo.
Head thrust test was the most reliable bedside test.
Dick Halpick’s and calorie test positive only in peripheral vertigo.
All the bedside tests used in this study were very much significant for vertigo with the
‘P’ value of <0.001
Determining the underlying Fermi surface of strongly correlated superconductors
The notion of a Fermi surface (FS) is one of the most ingenious concepts
developed by solid state physicists during the past century. It plays a central
role in our understanding of interacting electron systems. Extraordinary
efforts have been undertaken, both by experiment and by theory, to reveal the
FS of the high temperature superconductors (HTSC), the most prominent strongly
correlated superconductors. Here, we discuss some of the prevalent methods used
to determine the FS and show that they lead generally to erroneous results
close to half filling and at low temperatures, due to the large superconducting
gap (pseudogap) below (above) the superconducting transition temperature. Our
findings provide a perspective on the interplay between strong correlations and
superconductivity and highlight the importance of strong coupling theories for
the characterization as well as the determination of the underlying FS in ARPES
experiments
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