892 research outputs found
Statistical Modeling Of Effective Temperature With Cosmic Ray Flux
The increasing frequency of sporadic weather patterns in the last decade, especially major winter storms, demands improvements in current weather forecasting techniques. Recently, there are growing interests in stratospheric forecasting because of its potential enhancements of weather forecasts. The dominating factors of northern hemisphere wintertime variation of the general circulation in the stratosphere is a phenomenon called stratospheric sudden warming (SSW) events. It is shown in multiple studies that SSW and cosmic ray muon flux variations are strongly correlated with the effective atmospheric temperature changes, which suggests that cosmic ray detectors could be potentially used as meteorological applications, especially for monitoring SSW events.
A method for determining the effective temperature with cosmic ray flux measurements is studied in this work by using statistical modeling techniques, such as k-fold cross validation and partial least square regression. This method requires the measurement of the vertical profile of the atmospheric temperature, typically measured by radiosonde, for training the model. In this study, cosmic ray flux measured in Atlanta and Yakutsk are chosen for demonstrating this novel technique.
The results of this study show the possibility of realtime monitoring on effective temperature by simultaneous measurement of cosmic ray muon and neutron flux. This technique can also be used for studying the historical SSW events using the past world wide cosmic ray data
Cook blind: Enhancing cooking experiences for visually-impaired people
This paper introduces a new method to assist visually-impaired people to find what they need in order to complete cooking. Following the design thinking made by me at the beginning of my research, I started to create a new design based on target users` suggestions and preferences. This study focuses on the demands and user experiences of visually impaired people, the integration of design principles adapted from industrial design, user-centered design, and interaction design. I recorded the daily activities of the visually impaired individuals, and then investigated the most reasonable and effective solutions. My method of recording these individuals’ daily activates was via verbal interview, video recording interview, and online user research. Each method offered particular advantages to identifying the specific demands and needs of the visually impaired. With these methods, I conducted a series of user studies in order to understand the features of each research method including advantages and disadvantages. Then I devised my original design concept through the synthesis of research results. During the last round of the study, I shared my design with visually impaired persons in order to test the effectiveness of the new design by comparing visually impaired people`s activities with and without this new design
Nonlinear Hall effect as a signature of electronic phase separation in the semimetallic ferromagnet EuB6
This work reports a study of the nonlinear Hall Effect (HE) in the
semimetallic ferromagnet EuB6. A distinct switch in its Hall resistivity slope
is observed in the paramagnetic phase, which occurs at a single critical
magnetization over a wide temperature range. The observation is interpreted as
the point of percolation for entities of a more conducting and magnetically
ordered phase in a less ordered background. With an increasing applied magnetic
field, the conducting regions either increase in number or expand beyond the
percolation limit, hence increasing the global conductivity and effective
carrier density. An empirical two-component model expression provides excellent
scaling and a quantitative fit to the HE data and may be applicable to other
correlated electron systems.Comment: 15 Pages, 4 Figures. Accepted for publication in Phys. Rev. Let
Enhanced critical current density of MgB2 superconductor synthesized in high magnetic fields
The effect of high magnetic fields on the current carrying properties of both
MgB2 bulks and Fe-sheathed tapes was investigated following different thermal
sequences. It is found that application of a large magnetic field during
processing results in the quite uniform microstructure and the better
connectivity between the MgB2 grains. As a result, the Jc of these samples has
shown much higher value than that of the MgB2 samples in the absence of
magnetic field. The possible mechanism of the Jc enhancement under an external
magnetic field is also discussed.Comment: Presented at ISS2005, Tsukuba, 24-26 Oct., 2005; Revised versio
Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
As an exemplary Kondo insulator, SmB6 has been studied for several decades;
however, direct evidence for the development of the Kondo coherent state and
the evolution of the electronic structure in the material has not been obtained
due to the rather complicated electronic and thermal transport behavior.
Recently, these open questions attracted increasing attention as the emergence
of a time-reversal invariant topological surface state in the Kondo insulator
has been suggested. Here, we use point-contact spectroscopy to reveal the
temperature dependence of the electronic states in SmB6. We demonstrate that
SmB6 is a model Kondo insulator: below 100 K, the conductance spectra reflect
the Kondo hybridization of Sm ions, but below ~ 30 K, signatures of inter-ion
correlation effects clearly emerge. Moreover, we find evidence that the
low-temperature insulating state of this exemplary Kondo lattice compound
harbors conduction states on the surface, in support of predictions of
nontrivial topology in Kondo insulators.Comment: Accepted for publication in Physical Review
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