14,409 research outputs found
Phase-coexisting patterns, horizontal segregation and controlled convection in vertically vibrated binary granular mixtures
We report new patterns, consisting of coexistence of sub-harmonic/harmonic
and asynchronous states [for example, a granular gas co-existing with (i)
bouncing bed, (ii) undulatory subharmonic waves and (iii) Leidenfrost-like
state], in experiments on vertically vibrated binary granular mixtures in a
Heleshaw-type cell. Most experiments have been carried out with equimolar
binary mixtures of glass and steel balls of same diameter by varying the total
layer-height () for a range of shaking acceleration (). All patterns
as well as the related phase-diagram in the ()-plane have been
reproduced via molecular dynamics simulations of the same system. The
segregation of heavier and lighter particles along the horizontal direction is
shown to be the progenitor of such phase-coexisting patterns as confirmed in
both experiment and simulation. At strong shaking we uncover a {\it partial}
convection state in which a pair of convection rolls is found to coexist with a
Leidenfrost-like state. The crucial role of the relative number density of two
species on controlling the buoyancy-driven granular convection is demonstrated.
A possible model for spontaneous horizontal segregation is suggested based on
anisotropic diffusion
Low-energy, planar magnetic defects in BaFe2As2: nanotwins, twins, antiphase and domain boundaries
In BaFe2As2, structural and magnetic planar defects begin to proliferate
below the structural phase transition, affecting descriptions of magnetism and
superconductivity. We study using density-functional theory the stability and
magnetic properties of competing antiphase and domain boundaries, twins and
isolated twins (twin nuclei) - spin excitations proposed and/or observed.
These nanoscale defects have very low surface energy (-~Jm),
with twins favorable to the mesoscale. Defects exhibit smaller moments confined
near their boundaries -- making a uniform-moment picture inappropriate for
long-range magnetic order in real samples. {\it{Nano}}twins explain features in
measured pair distribution functions, so should be considered when analyzing
scattering data. All these defects can be weakly mobile and/or have
fluctuations that lower assessed "ordered" moments from longer spatial and/or
time averaging, and should be considered directly.Comment: 6 pages, 6 figures, 1 tabl
Estimation of losses for adobe buildings in Pakistan
Adobe buildings are vulnerable to seismic forces. Large scale destructions and casualties have been caused due
to the collapse of adobe buildings during the past earthquakes. A significant number of adobe structures exist in
different parts of Pakistan, similar to other parts of the world. Since Pakistan lies in a seismic active region, it is
necessary to assess the level of vulnerability of these buildings in order to estimate associated losses during a
seismic event. This paper presents the results of a study which was conducted to quantify damages to adobe
buildings based on their fragility curves. The adobe buildings were found to be highly vulnerable to low intensity
earthquakes. The vulnerability of these buildings has been compared with the European adobe buildings. It was
noted that Pakistani adobe buildings were slightly less resistant to earthquakes as compared to similar buildings
in Europe. Retrofitting solutions were suggested in order to increase the seismic capacity of adobe buildings in
Pakistan
Effect of disorder on the electronic properties of graphene: a theoretical approach
In order to manipulate the properties of graphene, its very important to
understand the electronic structure in presence of disorder. We investigate,
within a tight-binding description, the effects of disorder in the on-site
(diagonal disorder) term in the Hamiltonian as well as in the hopping integral
(off-diagonal disorder) on the electronic dispersion and density of states by
augmented space recursion method. Extrinsic off-diagonal disorder is shown to
have dramatic effects on the two-dimensional Dirac-cone, including asymmetries
in the band structures as well as the presence of discontinuous bands in
certain limits. Disorder-induced broadening, related to the scattering length
(or life-time) of electrons, is modified significantly with the increasing
strength of disorder. We propose that our theory is suitable to study the
effects of disorder in other 2D materials, e.g., a boron nitride monolayer.Comment: 11 pages, 8 figure
Potensi Penggunaan Koneksi Internet Instansi Pemerintah Bersama Masyarakat di Kota Makassar
Saat ini hampir seluruh instansi pemerintah maupun swasta telah melakukan penyewaan koneksi internet untuk memenuhi kebutuhan informasi masing-masing tak terkecuali pemerintah kota Makassar. Dengan sistem pembayaran dan pemakaian internet bulanan membuat instansi pemerintah tetap mendapatkan koneksi internet diluar jam kantor atau hari libur. Hal ini minimbulkan kemubassiran mengingat pada waktu-waktu tersebut koneksi internet tidak termanfaatkan sementara kebutuhan masyarakat akan akses internet belum tercukupi dengan baik. Berdasarkan hal itu maka penelitian ini dilakukan dengan tujuan untuk mengetahui potensi bandwidth internet instansi, Sumber Daya Manusia (pengelola jaringan), kebiasaan manajemen jaringan,waktu dan tanggapan terhadap ide pemakaian internet bersama masyarakat diluar jam kantor dan hari libur. Penelitian ini dilakukan melalui wawancara dan observasi secara langsung di 12 instansi pemerintah kota Makassar. Data yang diperoleh dianalisis secara kualitatif untuk menggambarkan potensi-potensi tersebut. Potensi bandwidth internet instansi adalah sebesar 26,5 MBps, terdapat 5 instansi yang terbiasa melakukan manajemen dan monitoring bandwidth dan hanya 3 instansi terbiasa melakukan filtering website. Ketersediaan pengelola jaringan sudah 100% dengan 85% yang berlatar belakang pendidikan teknologi informasi, potensi waktu rata-rata 15-16 jam perhari dan 24 jam pada hari libur. Sepuluh dari dua belas instansi setuju apabila penggunaan internet bersama masyarakat diimplementasikan
Integration Of Mobile Based Queuing Systems
The amount of time and energy that is wasted if people queue for public services is a serious problem. More ever if that queuing done by busy or sick people. Because of busyness, a person sometimes has to complete several matters at different places in short period of time. Therefore we need a queuing system that is able to integrate all queuing services so that the public can do all queuing processes with more comfort without having to cram into a queue. In addition, by integrating all community queuing services can get services in several places just by registering through one application. The working system of this application is to distribute information on service position and estimated waiting time through an application. To design the system, a survey was carried out in several public service facilities in the cities of Makassar and Gowa Regency. Beside that, literature studies also were carried out on similar papers. System analysis and design using the SDLC method include planning, system analysis and system design. It is expected that the results of this design can become a model that can be used as an appropriate reference to implement integration of mobile-based online queuing systems
Interplay of chemical pressure and hydrogen insertion effects in from first principles
Investigations within the local spin density functional theory (LSDF) of the
intermetallic hydride system were carried out for discrete
model compositions in the range . The aim of this
study is to assess the change of the cerium valence state in the neighborhood
of the experimental hydride composition, . In agreement
with experiment, the analyses of the electronic and magnetic structures and of
the chemical bonding properties point to trivalent cerium for . In contrast, for lower hydrogen amounts the hydride system stays in an
intermediate-valent state for cerium, like in . The influence
of the insertion of hydrogen is addressed from both the volume expansion and
chemical bonding effects. The latter are found to have the main influence on
the change of Ce valence character. Spin polarized calculations point to a
finite magnetic moment carried by the Ce states; its magnitude increases
with in the range
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