8,106 research outputs found
The Students\u27 View of the Functions of Mother Tongue in General English Program of ABC Course
This study aimed to find out the students ‘opinions on the use of mother tongue and its functions in Indonesian EFL classrooms. The data were the interviews with a total six students from level 1, 2 and 3 comprising one high achiever student and one low achiever student from each level. The findings show that all of the students agree that Indonesian can be occasionally used in the classroom by both teacher and students for a number of reasons: for the teacher to explain new and difficult vocabularies, explain grammar rules, organize tasks, maintain discipline, gain contact with individual students, for the students to ask and answer questions, communicate and discuss with classmates and for translating activities. The findings also show that the low proficiency students prefer to use Indonesian more than the higher proficiency students because of lack of vocabular
Fracture Model Reduction and Optimization for Forchheimer Flows in Reservoir
In this study, we analyze the flow filtration process of slightly
compressible fluids in fractured porous media. We model the coupled fractured
porous media system, where the linear Darcy flow is considered in porous media
and the nonlinear Forchheimer equation is used inside the fracture.
Flow in the fracture is modeled as a reduced low dimensional BVP which is
coupled with an equation in the reservoir. We prove that the solution of the
reduced model can serve very accurately to approximate the solution of the
actual high-dimensional flow in reservoir fracture system, because the
thickness of the fracture is small. In the analysis we consider two types of
Forchhemer flows in the fracture: isotropic and anisotropic, which are
different in their nature.
Using method of reduction, we developed a formulation for an optimal design
of the fracture, which maximizes the capacity of the fracture in the reservoir
with fixed geometry. Our method, which is based on a set point control
algorithm, explores the coupled impact of the fracture geometry and
beta-Forchheimer coefficient
X-ray/gamma-ray flux correlations in the BL Lacs Mrk 421 and 501 using HAWC data
The HAWC gamma ray observatory is located at the Sierra Negra Volcano in
Puebla, Mexico, at an altitude of 4,100 meters. HAWC is a wide field of view
array of 300 water Cherenkov detectors that are continuously surveying ~ 2sr of
the sky, operating since March 2015. The large collected data sample allows
HAWC to perform an unbiased monitoring of the BL Lac Mrk 421. This is the
closest and brightest known extragalactic high-synchrotron-peaked BL Lac in the
gamma-ray/X- ray bands and is extensively monitored by the Large Area Telescope
(LAT) on-board the Fermi satellite, and the BAT and XRT instruments of the
Swift satellite. In this work, we use 25 months of HAWC data together with
Swift-XRT data to characterize potential correlations between both wavelengths.
This analysis shows that HAWC and Swift-XRT data are correlated even stronger
than expected for quasi-simultaneous observations.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
Runaway dilatonic domain walls
We explore the stability of domain wall and bubble solutions in theories with
compact extra dimensions. The energy density stored inside of the wall can
destabilize the volume modulus of a compactification, leading to solutions
containing either a timelike singularity or a region where space
decompactifies, depending on the metric ansatz. We determine the structure of
such solutions both analytically and using numerical simulations, and analyze
how they arise in compactifications of Einstein--Maxwell theory and Type IIB
string theory. The existence of instabilities has important implications for
the formation of networks of topological defects and the population of vacua
during eternal inflation.Comment: 29 pages with 19 figures. Replaced to match published versio
Open Charm and Beauty at Ultrarelativistic Heavy Ion Colliders
Important goals of RHIC and LHC experiments with ion beams include the
creation and study of new forms of matter, such as the Quark Gluon Plasma.
Heavy quark production and attenuation will provide unique tomographic probes
of that matter. We predict the suppression pattern of open charm and beauty in
collisions at RHIC and LHC energies based on the DGLV formalism of
radiative energy loss. A cancelation between effects due to the
energy dependence of the high slope and heavy quark energy loss is
predicted to lead to surprising similarity of heavy quark suppression at RHIC
and LHC.Comment: 4 pages, 6 *.eps files combined into 4 figure
Effective generation of cat and kitten states
We present an effective method of coherent state superposition (cat state)
generation using single trapped ion in a Paul trap. The method is
experimentally feasible for coherent states with amplitude using
available technology. It works both in and beyond the Lamb-Dicke regime.Comment: 11 pages, 8 figure
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