354,270 research outputs found
Anomalously light mesons in a (1+1)-dimensional supersymmetric theory with fundamental matter
We consider N=1 supersymmetric Yang-Mills theory with fundamental matter in
the large-N_c approximation in 1+1 dimensions. We add a Chern-Simons term to
give the adjoint partons a mass and solve for the meson bound states. Here
mesons are color-singlet states with two partons in the fundamental
representation but are not necessarily bosons. We find that this theory has
anomalously light meson bound states at intermediate and strong coupling. We
also examine the structure functions for these states and find that they prefer
to have as many partons as possible at low longitudinal momentum fraction.Comment: 14 pages, 3 figures, LaTe
Swinging and tumbling of elastic capsules in shear flow
The deformation of an elastic micro-capsule in an infinite shear flow is
studied numerically using a spectral method. The shape of the capsule and the
hydrodynamic flow field are expanded into smooth basis functions. Analytic
expressions for the derivative of the basis functions permit the evaluation of
elastic and hydrodynamic stresses and bending forces at specified grid points
in the membrane. Compared to methods employing a triangulation scheme, this
method has the advantage that the resulting capsule shapes are automatically
smooth, and few modes are needed to describe the deformation accurately.
Computations are performed for capsules both with spherical and ellipsoidal
unstressed reference shape. Results for small deformations of initially
spherical capsules coincide with analytic predictions. For initially
ellipsoidal capsules, recent approximative theories predict stable oscillations
of the tank-treading inclination angle, and a transition to tumbling at low
shear rate. Both phenomena have also been observed experimentally. Using our
numerical approach we could reproduce both the oscillations and the transition
to tumbling. The full phase diagram for varying shear rate and viscosity ratio
is explored. While the numerically obtained phase diagram qualitatively agrees
with the theory, intermittent behaviour could not be observed within our
simulation time. Our results suggest that initial tumbling motion is only
transient in this region of the phase diagram.Comment: 20 pages, 7 figure
Tensile and Compressive Constitutive Response of 316 Stainless Steel at Elevated Temperatures
Creep rate in compression is lower by factors of 2 to 10 than in tension if the microstructure of the two specimens is the same and are tested at equal temperatures and equal but opposite stresses. Such behavior is characteristic for monotonic creep and conditions involving cyclic creep. In the latter case creep rate in both tension and compression progressively increases from cycle to cycle, rendering questionable the possibility of expressing a time stabilized constitutive relationship. The difference in creep rates in tension and compression is considerably reduced if the tension specimen is first subjected to cycles of tensile creep (reversed by compressive plasticity), while the compression specimen is first subjected to cycles of compressive creep (reversed by tensile plasticity). In both cases, the test temperature is the same and the stresses are equal and opposite. Such reduction is a reflection of differences in microstructure of the specimens resulting from different prior mechanical history
Method of crystallization
A method is described for refining or growing bulk single crystals in an environment substantially free of gravity. The base material is suspended, positioned, and shaped as a containerless melt by wetting forces. Because no crucible is required, high temperature refractory materials can be processed
Transmission through a n interacting quantum dot in the Coulomb blockade regime
The influence of electron-electron (e-e) interactions on the transmission
through a quantum dot is investigated numerically for the Coulomb blockade
regime. For vanishing magnetic fields, the conductance peak height statistics
is found to be independent of the interactions strength. It is identical to the
statistics predicted by constant interaction single electron random matrix
theory and agrees well with recent experiments. However, in contrast to these
random matrix theories, our calculations reproduces the reduced sensitivity to
magnetic flux observed in many experiments. The relevant physics is traced to
the short range Coulomb correlations providing thus a unified explanation for
the transmission statistics as well as for the large conductance peak spacing
fluctuations observed in other experiments.Comment: Final version as publishe
Developing Mathematical Learning Device Using Ttw (Think- Talk-Write) Strategy Assisted By Learning Cd To Foster Mathematical Communication
This research aims to produce mathematical learning device or tool using TTW strategy that is valid, practical, and effective. The developed device consists of syllabi, Learning Implementation Plan (RPP), Student Reading which is packaged in CD (BBS), and an evaluation tool. Receiver of treatment or Subjects are the eighth grade students of Muhammadiyah Junior High School in Purworejo. First experiment held in the class A of eighth grade students aimed to determine the legibility of device and the level of difficulty, distinguishing features, and reliability test learning outcomes. Second experiment conducted in class C of eighth grade students aimed to verify the practicality of the device and the effectiveness of learning using developed devices, whereas the class G is as control class. Results from 5 validations of the device are: the mean score of syllabi is 3.48; RPP is 3.79; BBS is 3.73; LKS is 3.73; assessment tool is 3.71 (on scale 1-4). Such results mean that validation criteria of the device is valid. The score of experiment results showed that the criteria of learning process is 3.80; the students’ response is 93.85%; the teacher’s score is 3.91, that means it’s a practical device. Learning using the devices results a classical learning mastery, and achievement test of an experimental class is better than the control class. Furthermore, student’s activity has a positive influence for achievement, so it’s the effective device.
Key words: developed device, Think-Talk-Write (TTW), the mathematical learnin
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