3,342 research outputs found
Axiomatic Foundations for the Principle of Entropy Increase
We show that the principle of entropy increase may be exactly founded on a
few axioms valid not only for quantum and classical statistics, but also for a
wide range of statistical processes.Comment: 8 page
A General Information Theoretical Proof for the Second Law of Thermodynamics
We show that the conservation and the non-additivity of the information,
together with the additivity of the entropy make the entropy increase in an
isolated system. The collapse of the entangled quantum state offers an example
of the information non-additivity. Nevertheless, the later is also true in
other fields, in which the interaction information is important. Examples are
classical statistical mechanics, social statistics and financial processes. The
second law of thermodynamics is thus proven in its most general form. It is
exactly true, not only in quantum and classical physics but also in other
processes, in which the information is conservative and non-additive.Comment: 4 page
Service Learning Without Borders – Turning Peanut Shells to Fuel Briquettes in the Gambia
The need of firewood in the Gambia is leading to rapid deforestation. An engineering student team in our program was funded to convert peanut shells, an abundant agricultural waste from the country, into fuel briquette. By consulting the local contacts, the students developed a series of pressing devices and processes for the purpose. Then they compared the strength, burning rate and duration of burning of the briquettes, as well the difficulties to obtain binder and process the material. They finally settled to an easy to follow recipe and a very simple device to press the loose shells to briquettes. In the January of 2012, a student team went to 8 remote villages in rural Gambia. They demonstrated the briquetting process to the local people. The team was warmly received and all villages agreed to try out the method so they could preserve the dwindling forest while supporting the growing community
Information Conservation, Entropy Increase and the Statistical Irreversibility for an Isolated System
We consider the statistical irreversibility and its compatibility with the
reversible dynamics. The role played by the observation is analyzed in detail.
It makes our previous proof for the second law of thermodynamics clearer. On
this basis, we emphasize the importance and wide applicability for the second
law of thermodynamics. A new form of physics with this law being substituted by
the principle of information conservation is suggested. By the way, we also
solve the paradox of Schr\"odinger cat, and show that the universe will not go
to the so-called heat death spontaneously.Comment: 7 pages, 9 figur
Microheated substrates for patterning cells and controlling development
Here, we seek to control cellular development by devising a means through which cells can be subjected to a microheated environment in standard culture conditions. Numerous techniques have been devised for controlling cellular function and development via manipulation of surface environmental cues at the micro- and nanoscale. It is well understood that temperature plays a significant role in the rate of cellular activities, migratory behavior (thermotaxis), and in some cases, protein expression. Yet, the effects and possible utilization of micrometer-scale temperature fields in cell cultures have not been explored. Toward this end, two types of thermally isolated microheated substrates were designed and fabricated, one with standard backside etching beneath a dielectric film and another with a combination of surface and bulk micromachining and backside etching. The substrates were characterized with infrared microscopy, finite element modeling, scanning electron microscopy, stylus profilometry, and electrothermal calibrations. Neuron culture studies were conducted on these substrates to 1) examine the feasibility of using a microheated environment to achieve patterned cell growth and 2) selectively accelerate neural development on regions less than 100wide. Results show that attached neurons, grown on microheated regions set at 37, extended processes substantially faster than those incubated at 25on the same substrate. Further, unattached neurons were positioned precisely along the length of the heater filament (operating at 45) using free convection currents. These preliminary findings indicate that microheated substrates may be used to direct cellular development spatially in a practical manner.$hfillhbox[1414]
On the expected size of the 2d visibility complex
We study the expected size of the 2D visibility complex of randomly distributed objects in the plane. We prove that the asymptotic expected number of free bitangents (which correspond to 0-faces of the visibility complex) among unit discs (or polygons of bounded aspect ratio and similar size) is linear and exhibit bounds in terms of the density of the objects. We also make an experimental assessment of the size of the visibility complex for disjoint random unit discs. We provide experimental estimates of the onset of the linear behavior and of the asymptotic slope and y-intercept of the number of free bitangents in terms of the density of discs. Finally, we analyze the quality of our estimates in terms of the density of discs.
Star formation associated with the infrared dust bubble N68
We investigated the environment of the infrared dust bubble N68 and searched
for evidence of triggered star formation in its surroundings. We performed a
multiwavelength study of the nebula with data taken from several large-scale
surveys: GLIMPSE, MIPSGAL, IRAS, NVSS, GRS, and JCMT. We analyzed the spectral
profile and the distribution of the molecular gas (^{13}CO J = 1 - 0 and J = 3
- 2), and the dust in the environment of the N68. The position-velocity diagram
clearly shows that the N68 may be expanding outward. We used two three-color
images of the mid-infrared emission to explore the physical environment, and
one color-color diagram to investigate the distribution of young stellar
objects (YSOs). We found that the 24 \mu m emission is surrounded by the 8.0
\mu m emission. Morphologically, the 1.4 GHz continuum correlates strongly with
the 24 \mu m emission, and the ^{13}CO J = 1 - 0 and J = 3 - 2 emissions
correlate well with the 8.0 \mu m emission. We investigated two compact cores
located at the shell of the N68. The spectral intensity ratios of ^{13}CO J = 3
- 2 to J = 1 - 0 range from 5 to 0.3. In addition, young star objects, masers,
IRAS, and UC HII regions distribute at the shell of bubble. The active region
may be triggered by the expanding of the bubble N68.Comment: 10 pages, 11 figures, submited to RA
De-Trending Time Series for Astronomical Variability Surveys
We present a de-trending algorithm for the removal of trends in time series.
Trends in time series could be caused by various systematic and random noise
sources such as cloud passages, changes of airmass, telescope vibration or CCD
noise. Those trends undermine the intrinsic signals of stars and should be
removed. We determine the trends from subsets of stars that are highly
correlated among themselves. These subsets are selected based on a hierarchical
tree clustering algorithm. A bottom-up merging algorithm based on the departure
from normal distribution in the correlation is developed to identify subsets,
which we call clusters. After identification of clusters, we determine a trend
per cluster by weighted sum of normalized light-curves. We then use quadratic
programming to de-trend all individual light-curves based on these determined
trends. Experimental results with synthetic light-curves containing artificial
trends and events are presented. Results from other de-trending methods are
also compared. The developed algorithm can be applied to time series for trend
removal in both narrow and wide field astronomy.Comment: Revised version according to the referee's second revie
Muon Anomalous Magnetic Moment and Lepton Flavor Violation
A non-universal interaction, which involves only the third family leptons
induces lepton flavor violating couplings and contributes to the anomalous
magnetic moment of muon. In this paper, we study the effects of non-universal
interaction on muon (g-2) and rare decay by using an
effective lagrangian technique, and a phenomenological model where
couples only to the third family lepton. We find that the deviation
from the theory can be explained and the induced rate
could be very close to the current experimental limit. In the model,
has to be lighter than 2.6 TeV.Comment: references added, the version to appear in PR
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