39,393 research outputs found
Competition of L21 and XA Ordering in Fe2CoAl Heusler Alloy: A First-Principles Study
The physical properties of Fe2CoAl (FCA) Heusler alloy are systematically
investigated using the first-principles calculations within generalized
gradient approximation (GGA) and GGA+U. The influence of atomic ordering with
respect to the Wyckoff sites on the phase stability, magnetism and half
metallicity in both the conventional L21 and XA phases of FCA is focused in
this study. Various possible hypothetical structures viz., L21, XA-I, and XA-II
are prepared by altering atomic occupancies at their Wyckoff sites. At first,
we have determined the stable phase of FCA considering various non-magnetic (or
paramagnetic), ferromagnetic (FM) and antiferromagnetic (AFM) configurations.
Out of these, the ferromagnetic (FM) XA-I structure is found to be
energetically most stable. The total magnetic moments per cell are not in
agreement with the Slater-Pauling (SP) rule in any phases; therefore, the
half-metallicity is not observed in any configurations. However, FM ordered
XA-I type FCA shows 78% spin polarization at EF. Interestingly, the results of
XA-I type FCA are closely matched with the experimental results.Comment: 15 pages, 6 figure
Correlations and Event-by-Event Fluctuations in High Multiplicity Events Produced in Pb-Pb Collisions
Analysis of high multiplicity events produced in 158A GeV/c
Pb-Pb collisions is carried out to study the event-by-event
fluctuations. The findings reveal that the method of scaled factorial moments
can be used to identify the events having densely populated narrow phase space
bins. A few events sorted out adopting this approach are individually analyzed.
It is observed that these events do exhibit large fluctuations in their
pseudorapidity, and azimuthal angle, distributions arising out
due to some dynamical reasons. Two particle -
correlation study applied to these events too indicates that some complex
two-dimensional structure of significantly high magnitude are present in these
events which might have some dynamical origin. The findings reveal that the
method of scaled factorial moments may be used as an effective triggering for
events with large dynamical fluctuations.Comment: 20 pages, 7 figures (Accepted for publication in Advances in High
Energy Physics
Modelling of Metal-Coating Delamination Incorporating Variable Environmental Parameters
A mathematical model for metal-coat delamination of degrading metal was developed incorporating multiple variable environmental parameters. Metal-coat delamination not only depends on the electrochemical reactions at metal-coat interface but also on the factors like the type of propagating metal ions and their varying concentration with annual weather changes, time of exposure of the coated objects, type of coated objects are stationary or mobile vehicles, frequency with which certain vehicles are operating in various environments e.g. controlled or uncontrolled in terms of environmental conditions. A cutting edge model has been developed to calculate the varying environmental conditions using iteration algorithm, time dependent uncertain position of objects like vehicle in various environments using stochastic approach, effect of seasonal changes on ionic compound's concentration using algebraic method and instantaneous failure probability due to varying conditions. Based on the developed model a detailed simulation study was conducted to investigate the metal-coat delamination process and the ways to regress the under coat metal corrosion
Event by Event Analysis of High Multiplicity Events Produced in 158 A GeV/c 208 Pb- 208 Pb Collisions
An extensive analysis of individual high multiplicity events produced in 158
A GeV /c 208Pb- 208Pb collisions is carried by adopting different methods to
examine the anomalous behavior of these rare events. A method of selecting the
events with densely populated narrow regions or spikes out of a given sample of
collision events is discussed.Employing this approach two events with large
spikes in their eta- and phi- distributions are selected for further analysis.
For the sake of comparison, another two events which do not exhibit such spikes
are simultaneously analyzed. The findings suggest that the systematic studies
of particle density fluctuations in one- and two-dimensional phase-spaces and
comparison with those obtained from the studies of correlation free Monte Carlo
events, would be useful for identifying the events with large dynamical
fluctuations. Formation of clusters or jet like phenomena in multihadronic
final states in individual events is also discussed and the experimental
findings are compared with the independent particle emission hypothesis by
carrying out Monte Carlo simulations
Sufficient conditions for unique global solutions in optimal control of semilinear equations with nonlinearity
We consider a semilinear elliptic optimal control problem possibly
subject to control and/or state constraints. Generalizing previous work we
provide a condition which guarantees that a solution of the necessary first
order conditions is a global minimum. A similiar result also holds at the
discrete level where the corresponding condition can be evaluated explicitly.
Our investigations are motivated by G\"unter Leugering, who raised the question
whether our previous results can be extended to the nonlinearity
. We develop a corresponding analysis and present several
numerical test examples demonstrating its usefulness in practice
Office quality classification theoretical and empirical issues
Office quality classification literature recognises identification of office classes through division of office market rent distribution into intervals but failed to provide sound theoretical framework and comprehensive empirical approach to this method. This paper theorised that as office rental levels are a function of office quality; high quality office classes should have their mean rents greater than average market rent and mean rents of low quality classes. Also that heterogeneous nature of property coupled with lack of perfect information to market participants could result into differential evaluation of rent and quality of the same property by different market participants. The behaviour of participants normally reflects in distribution of market rent by depicting natural breaks in the distribution that could be captured by univariate data exploration. Frequency and histograms of rent distributions that were assumed to depict the behaviour of market participants were used to divide rent distribution to intervals to identify office quality classes. The results of this classification were validated by discriminant analysis. 67% and 59% accuracies were achieved for estimation and holdout subsamples respectively. This paper extended theoretical and empirical approaches in office quality classification. The proposed empirical approach could be used in future classification research
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