1,598 research outputs found
Peranan Badan USAha Milik Desa ( Bumdes ) dalam Peningkatan Ekonomi Masyarakat ( Studi pada Bumdes Desa Pekan Tebih Kecamatan Kepenuhan Hulu Kabupaten Rokan Hulu )
This research aim to to know the Body Role of is Effort Countryside Property ( BUMDes) in Make-Up of Society Economics, specially society of consumer of fund BUMDes in Countryside of Week of Tebih of District of Fullness of Pate;Upstream of Sub-Province of Rokan Pate;Upstream. Research Population is some of consumer of fund of BUMDes of Countryside of Week of Tebih year 2013 counted 277 people and determination sampel use the method Proposional so that its sampel research amount to 42 people. In analysing research data use the descriptive method qualitative, only elaborating result from question interview the field momen
Stochastic excitation of non-radial modes I. High-angular-degree p modes
Turbulent motions in stellar convection zones generate acoustic energy, part
of which is then supplied to normal modes of the star. Their amplitudes result
from a balance between the efficiencies of excitation and damping processes in
the convection zones. We develop a formalism that provides the excitation rates
of non-radial global modes excited by turbulent convection. As a first
application, we estimate the impact of non-radial effects on excitation rates
and amplitudes of high-angular-degree modes which are observed on the Sun. A
model of stochastic excitation by turbulent convection has been developed to
compute the excitation rates, and it has been successfully applied to solar
radial modes (Samadi & Goupil 2001, Belkacem et al. 2006b). We generalize this
approach to the case of non-radial global modes. This enables us to estimate
the energy supplied to high-() acoustic modes. Qualitative arguments as
well as numerical calculations are used to illustrate the results. We find that
non-radial effects for modes are non-negligible:
- for high- modes (i.e. typically ) and for high values of ;
the power supplied to the oscillations depends on the mode inertia.
- for low- modes, independent of the value of , the excitation is
dominated by the non-diagonal components of the Reynolds stress term. We
carried out a numerical investigation of high- modes and we find that
the validity of the present formalism is limited to due to the
spatial separation of scale assumption. Thus, a model for very high-
-mode excitation rates calls for further theoretical developments, however
the formalism is valid for solar modes, which will be investigated in a
paper in preparation.Comment: 12 pages, accepted for publication in A&
Solar-like oscillation amplitudes and line-widths as a probe for turbulent convection in stars
Excitation of solar-like oscillations is attributed to turbulent convection
and takes place at the upper-most part of the outer convective zones.
Amplitudes of these oscillations depend on the efficiency of the excitation
processes as well as on the properties of turbulent convection. We present past
and recent improvements on the modeling of those processes. We show how the
mode amplitudes and mode line-widths can bring information about the turbulence
in the specific cases of the Sun and Alpha Cen A.Comment: 9 pages ; 3 figures ; invited talk given during the Symposium no. 239
"Convection in Astrophysics", International Astronomical Union., held 21-25
August, 2006 in Prague, Czech Republi
Solar-like oscillations in massive main-sequence stars. I. Asteroseismic signatures of the driving and damping regions
Motivated by the recent detection of stochastically excited modes in the
massive star V1449 Aql (Belkacem et al., 2009b), already known to be a
Cephei, we theoretically investigate the driving by turbulent convection. By
using a full non-adiabatic computation of the damping rates, together with a
computation of the energy injection rates, we provide an estimate of the
amplitudes of modes excited by both the convective region induced by the iron
opacity bump and the convective core. Despite uncertainties in the dynamical
properties of such convective regions, we demonstrate that both are able to
efficiently excite modes above the CoRoT observational threshold and the
solar amplitudes. In addition, we emphasise the potential asteroseismic
diagnostics provided by each convective region, which we hope will help to
identify the one responsible for solar-like oscillations, and to give
constraints on this convective zone. A forthcoming work will be dedicated to an
extended investigation of the likelihood of solar-like oscillations across the
Hertzsprung-Russell diagram.Comment: 9 pages, 14 figures, accepter in A&
New bounds on the signed total domination number of graphs
In this paper, we study the signed total domination number in graphs and
present new sharp lower and upper bounds for this parameter. For example by
making use of the classic theorem of Turan, we present a sharp lower bound on
this parameter for graphs with no complete graph of order r+1 as a subgraph.
Also, we prove that n-2(s-s') is an upper bound on the signed total domination
number of any tree of order n with s support vertices and s' support vertives
of degree two. Moreover, we characterize all trees attainig this bound.Comment: This paper contains 11 pages and one figur
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