398 research outputs found
Pengaruh Lama Penyinaran Gelombang Mikro Terhadap Pembentukan Struktur Dan Sifat Thermal Karbon Hitam Dari Bambu Ori (Bambusa Arundinacea) Dan Bambu Petung (Dendrocalamus Asper)
Bambu merupakan salah satu tumbuhan yang memiliki bentuk batang tinggi, berongga, berbentuk bulat dan memiliki kekuatan yang baik. Penelitian ini bertujuan mempelajari pengaruh proses penyinaran gelombang mikro terhadap pembentukan struktur dan sifat thermal karbon hitam dari bambu ori (Bambusa arundinacea) dan bambu petung (Dendrocalamus asper). Metode sintesis karbon hitam yaitu dengan melakukan penyinaran gelombang mikro dengan variasi lama penyinaran selama 1, 2, 3, 4, dan 5 menit, serta variasi daya 400, 600, dan 800 watt. Pengujian nilai kalor terhadap karbon hitam untuk mengetahui potensi bahan bakar. Perubahan gugus fungsi diuji dengan Fourier Transforms Infrared Spectrometer. Untuk mengidentifikasi senyawa atau fasa, dilakukan pengujian X-Ray Difraction. Struktur mikro akan dipelajari menggunakan uji Scanning Electron Microscope. Hasil dari pengujian tersebut yaitu semakin lama pemanasan gelombang mikro, maka berat sisa yang dihasilkan semakin sedikit. Semakin tinggi daya, maka karbon yang dihasilkan semakin homogen. Waktu pemanasan yang semakin lama, mengakibatkan karbon yang terbentuk semakin baik dan homogen
Compact F-theory GUTs with U(1)_PQ
We construct semi-local and global realizations of SU(5) GUTs in F-theory
that utilize a U(1)_PQ symmetry to protect against dimension four proton decay.
Symmetries of this type, which assign charges to H_u and H_d that forbid a tree
level \mu term, play an important role in scenarios for neutrino physics and
gauge mediation that have been proposed in local F-theory model building. As
demonstrated in arXiv:0906.4672, the presence of such a symmetry implies the
existence of non-GUT exotics in the spectrum, when hypercharge flux is used to
break the GUT group and to give rise to doublet-triplet splitting. These
exotics are of precisely the right type to solve the unification problem in
such F-theory models and might also comprise a non-standard messenger sector
for gauge mediation. We present a detailed description of models with U(1)_PQ
in the semi-local regime, which does not depend on details of any specific
Calabi-Yau four-fold, and then specialize to the geometry of arXiv:0904.3932 to
construct three-generation examples with the minimal allowed number of non-GUT
exotics. Among these, we find a handful of models in which the D3-tadpole
constraint can be satisfied without requiring the introduction of
anti-D3-branes. Finally, because SU(5) singlets that carry U(1)_PQ charge may
serve as candidate right-handed neutrinos or can be used to lift the exotics,
we study their origin in compact models and motivate a conjecture for how to
count their zero modes in a semi-local setting.Comment: 73 pages, 5 figures, v2: minor corrections to 4.3 and 6.3.1,
reference adde
On the plane-wave cubic vertex
The exact bosonic Neumann matrices of the cubic vertex in plane-wave
light-cone string field theory are derived using the contour integration
techniques developed in our earlier paper. This simplifies the original
derivation of the vertex. In particular, the Neumann matrices are written in
terms of \mu-deformed Gamma-functions, thus casting them into a form that
elegantly generalizes the well-known flat-space solution. The asymptotics of
the \mu-deformed Gamma-functions allow one to determine the large-\mu behaviour
of the Neumann matrices including exponential corrections. We provide an
explicit expression for the first exponential correction and make a conjecture
for the subsequent exponential correction terms.Comment: 26 pages, 1 figure; harvmac (b); v4: minor corrections in appendix
JURNAL PENGABDIAN MASYARAKAT PENGADAAN RUMAH BELAJAR UNTUK MENINGKATKAN MINAT BELAJAR SISWA/I SDN 003 KEPENUHAN
This study examines the low interest in learning in students in the learning process at school. The purpose of this research is to increase students' interest in learning through the provision of learning houses. The research subjects are students of SDN 003 Kepenuhan from class I to class VI. Data collection techniques were through observation and interviews. The results showed an increase in students' interest in learning based on data on increasing student abilities before and after the opening of the learning house. This study was declared to have met the success requirements above 80% of the initial conditions before the opening of this learning hous
An Instanton Toolbox for F-Theory Model Building
Several dimensionful parameters needed for model building can be engineered
in a certain class of SU(5) F-theory GUTs by adding extra singlet fields which
are localized along pairwise intersections of D7-branes. The values of these
parameters, however, depend on dynamics external to the GUT which causes the
singlets to acquire suitable masses or expectation values. In this note, we
demonstrate that D3-instantons which wrap the same 4-cycle as one of the
intersecting D7's can provide precisely the needed dynamics to generate several
important scales, including the supersymmetry-breaking scale and the
right-handed neutrino mass. Furthermore, these instantons seem unable to
directly generate the \mu term suggesting that, at least in this class of
models, it should perhaps be tied to one of the other scales in the problem.
More specifically, we study the simple system consisting of a pair of D7-branes
wrapping del Pezzo surfaces which intersect along a curve of genus 0
or 1 and classify all instanton configurations which can potentially contribute
to the superpotential. This allows one to formulate topological conditions
which must be imposed on \Sigma for various model-building applications. Along
the way, we also observe that the construction of arXiv:0808.1286 which
engineers a linear superpotential in fact realizes an O'Raifeartaigh model at
the KK scale whose 1-loop Coleman-Weinberg potential generically leads to a
metastable, long-lived SUSY-breaking vacuum.Comment: 18 pages, 2 figures; v2: updated to reflect corrections in v2 of
0808.128
Radiative Scalar Meson Decays in the Light-Front Quark Model
We construct a relativistic wavefunction for scalar mesons within the
framework of light-front quark model(LFQM). This scalar wavefunction is used to
perform relativistic calculations of absolute widths for the radiative decay
processes, and
which incorporate the effects of glueball-
mixing. The mixed physical states are assumed to be ,and
for which the flavor-glue content is taken from the mixing
calculations of other works. Since experimental data for these processes are
poor, our results are compared with those of a recent non-relativistic model
calculation. We find that while the relativistic corrections introduced by the
LFQM reduce the magnitudes of the decay widths by 50-70%, the relative
strengths between different decay processes are fairly well preserved. We also
calculate decay widths for the processes and
(0^{++})\to\gamma\gamm involving the light scalars and
to test the simple model of these mesons. Our results of
model for these processes are not quite consistent with well-established data,
further supporting the idea that and are not conventional
states.Comment: 10 pages, 4 figure
On the exact open-closed vertex in plane-wave light-cone string field theory
The open-closed vertex in the maximally supersymmetric type IIB plane-wave
light-cone string field theory is considered and an explicit solution for the
bosonic part of the vertex is derived, valid for all values of the mass
parameter, \mu. This vertex is of relevance to IIB plane-wave orientifolds, as
well as IIB plane-wave strings in the presence of D-branes and their gauge
theory duals. Methods of complex analysis are used to develop a systematic
procedure for obtaining the solution. This procedure is first applied to the
vertex in flat space and then extended to the plane-wave case. The plane-wave
solution for the vertex requires introducing certain ``\mu-deformed Gamma
functions'', which are generalizations of the ordinary Gamma function. The
behaviour of the Neumann matrices is graphically illustrated and their
large-\mu asymptotics are analysed.Comment: 35 pages, 7 figures; v4: minor changes in appendi
Review of AdS/CFT Integrability: An Overview
This is the introductory chapter of a review collection on integrability in
the context of the AdS/CFT correspondence. In the collection we present an
overview of the achievements and the status of this subject as of the year
2010.Comment: 31 pages, v2: reference added, references to other chapters updated,
v3: footnote 1 on location of references added, v4: minor changes, references
added, accepted for publication in Lett. Math. Phys, v5: minor corrections,
links to chapters updated, attached IntAdS.pdf with all chapters in one file,
see http://arxiv.org/src/1012.3982/anc/IntAdS.pdf or
http://www.phys.ethz.ch/~nbeisert/IntAdS.pd
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