24,812 research outputs found
A point symmetry based method for transforming ODEs with three-dimensional symmetry algebras to their canonical forms
We provide an algorithmic approach to the construction of point
transformations for scalar ordinary differential equations that admit
three-dimensional symmetry algebras which lead to their respective canonical
forms
A Unified Approach towards Describing Rapidity and Transverse Momentum Distributions in Thermal Freeze-Out Model
We have attempted to describe the rapidity and transverse momentum spectra,
simultaneously, of the hadrons produced in the Ultra-relativistic Nuclear
Collisions. This we have tried to achieve in a single statistical thermal
freeze-out model using single set of parameters. We assume the formation of a
hadronic gas in thermo-chemical equilibrium at the freeze-out. The model
incorporates a longitudinal as well as a transverse hydrodynamic flow. We have
also found that the role of heavier hadronic resonance decay is important in
explaining the particle spectra.Comment: 22 pages, 11 figure
Corrections to Tribimaximal Mixing from Nondegenerate Phases
We propose a seesaw scenario that possible corrections to the tribimaximal
pattern of lepton mixing are due to the small phase splitting of the
right-handed neutrino mass matrix. we show that the small deviations can be
expressed analytically in terms of two splitting parameters( and
) in the leading order. The solar mixing angle favors a
relatively smaller value compared to zero order value (), and the
Dirac type CP phase chooses a nearly maximal one. The two Majorana
type CP phases and turn out to be a nearly linear dependence.
Also a normal hierarchy neutrino mass spectrum is favored due to the stability
of perturbation calculations.Comment: 19 pages 6 figures, Accepted by Mod. Phy. Lett.
Break Even Analysis of Mining Projects
The economics of the resources industry are unique. All mining is subject to uncertainties not applicable to other industries. Every mine is different. Industry economics are difficult to quantify and categorize. Information is very costly.
In major mining countries, there is now a real dichotomy. The products of the minerals industry are essential primary ingredients in almost everything used in an advanced society, yet their availability is often taken for granted. In the developed world, the value of mining is increasingly being called into question. The difficulty in making profits is compounded by political uncertainties and environmental restrictions on top of the uncertainties created by nature.
Costing and evaluation of any mining development are necessarily based on a specific plan, which has to be prepared assuming certain ore body characteristics. However ore bodies are seldom clearly defined, and the effort to find and delineate them is itself an economically significant task. The economics of mining will determine what parts are or are not included in the definition of ore. When mine economics change, the amount of material in the ground does not change, but the amount of economically viable ore does change. The amount of economically viable ore is also dependent on the assumptions used for its calculation and can change with a change in assumptions.
The break-even point for a product is the point where total revenue received equals the total costs associated with the sale of the product. It has certain assumptions such as, selling prices will remain constant at all sales level, there is a linear relationship between sales volume and costs and production and sales quantities are equal. At the same time it suffers from certain limitations as break-even analysis is only a supply side (i.e. costs only) analysis, as it tells you nothing about what sales are actually likely to be for the product at these various prices
Hydrophobicity properties of graphite and reduced graphene oxide of the polysulfone (PSf) mixed matrix membrane
Hydrophobicity properties of graphite and reduced graphene oxide (rGO) (from exfoliated graphite/rGO) towards PSf polymer membrane characteristic and properties at different additives weight concentrations (1, 2, 3, 4 and 5 wt. %) were investigated. Both PSF/graphite and PSf/rGO membranes were characterized in term of hydrophobicity, surface bonding, surface roughness and porosity. FTIR peaks revealed that membrane with graphite and reduced graphene oxide nearly diminished their O-H bonding which was opposite to the graphene oxide peak that shows a strong O-H bonding as increased exfoliated times. These results were in line with the contact angle results that showed strong hydrophobicity of graphite and reduced graphene oxide membranes as increased these additives concentration. The effect of strong hydrophobicity in these membranes also has resulted in smoother surface roughness compared to pristine PSf membrane. Further investigation of the performance of water flux also proved that both above membranes have strong hydrophobic effect, with the lowest pure water flux rate (L/m2h) was given by PSf/rGO 3% membrane at 19.2437 L/m2h
Revisiting the Optimal PMU Placement Problem in Multi-Machine Power Networks
To provide real-time visibility of physics-based states, phasor measurement
units (PMUs) are deployed throughout power networks. PMU data enable real-time
grid monitoring and control -- and is essential in transitioning to smarter
grids. Various considerations are taken into account when determining the
geographic, optimal PMU placements (OPP). This paper focuses on the
control-theoretic, observability aspect of OPP. A myriad of studies have
investigated observability-based formulations to determine the OPP within a
transmission network. However, they have mostly adopted a simplified
representation of system dynamics, ignored basic algebraic equations that model
power flows, disregarded including renewables such as solar and wind, and did
not model their uncertainty. Consequently, this paper revisits the
observability-based OPP problem by addressing the literature's limitations. A
nonlinear differential algebraic representation (NDAE) of the power system is
considered and implicitly discretized -- using various different discretization
approaches -- while explicitly accounting for uncertainty. A moving horizon
estimation approach is explored to reconstruct the joint differential and
algebraic initial states of the system, as a gateway to the OPP problem which
is then formulated as a computationally tractable integer program (IP).
Comprehensive numerical simulations on standard power networks are conducted to
validate various aspects of this approach and test its robustness to various
dynamical conditions
Colorizing gray level images by using wavelet filters
© 2019 IEEE. This paper discusses a new algorithm to produce colored version of gray scale natural still images. This algorithm employs artificial neural network (ANN) to predict RGB channels using the Discrete Wavelet Transform (DWT). A group of natural color images are used to train three ANNs. The trained networks estimate low resolution RGB layers of the gray scale image which are the best match to the trained images. The colored version of the image is produced form the predicted RGB layers and information form grayscale image. The performances of the new algorithm are analyzed subjectively and objectively using the peak signal to noise and Structural Similarity, as well as it is compared to similar algorithm based on discrete cosine transform. Acceptable colorized images were obtained from different still images
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