Acoustic particle separation

A method is described which uses acoustic energy to separate particles of different sizes, densities, or the like. The method includes applying acoustic energy resonant to a chamber containing a liquid of gaseous medium to set up a standing wave pattern that includes a force potential well wherein particles within the well are urged towards the center, or position of minimum force potential. A group of particles to be separated is placed in the chamber, while a non-acoustic force such as gravity is applied, so that the particles separate with the larger or denser particles moving away from the center of the well to a position near its edge and progressively smaller lighter particles moving progressively closer to the center of the well. Particles are removed from different positions within the well, so that particles are separated according to the positions they occupy in the well

Acoustically induced oscillation and rotation of a large drop in space

A 2.5 cm diameter water drop was successfully deployed and manipulated in a triaxial acoustic resonance chamber during a 240 sec low-gravity SPAR rocket flight. Oscillation and rotation were induced by modulating and phase shifting the signals to the speakers. Portions of the film record were digitized and analyzed. Spectral analysis brought out the n = 2, 3, 4 free oscillation modes of the drop, its very low-frequency center-of-mass motion in the acoustic potential well, and the forced oscillation frequency. The drop boundaries were least-square fitted to general ellipses, providing eccentricities of the distorted drop. The normalized equatorial area of the rotating drop was plotted vs a rotational parameter, and was in excellent agreement with values derived from the theory of equilibrium shapes of rotating liquid drops

The 8-h tide in the mesosphere and lower thermosphere over Collm (51.3° N; 13.0° E), 2004–2011

The horizontal winds in the mesosphere and lower thermosphere (MLT) at heights of about 80–100 km have been measured continuously since summer 2004 using an all-sky 36.2 MHz VHF meteor radar at Collm, Germany (51.3° N, 13° E). A climatology of the 8-h solar tide has been constructed from these data. The amplitude shows a seasonal behaviour with maximum values during the equinoxes, and it is generally increasing with altitude. The largest amplitudes are measured in autumn, partly reaching values up to 15 m s⁻¹. The phase, defined as the time of maximum eastward or northward wind, respectively, has earlier values in winter and later ones in summer. Except for summer, the phase difference between the zonal and meridional components is close to +2 h, indicating circular polarization of the tidal components. The vertical wavelengths are short in summer (~20 km) but significantly longer during the rest of the year. The terdiurnal tide is generally assumed to originate from either a terdiurnal component of solar heating or nonlinear interaction between the diurnal and semidiurnal tide. Analysing monthly means reveals positive correlation during the spring maximum, but negative correlation in autumn

On a generalization of Jacobi's elliptic functions and the Double Sine-Gordon kink chain

A generalization of Jacobi's elliptic functions is introduced as inversions of hyperelliptic integrals. We discuss the special properties of these functions, present addition theorems and give a list of indefinite integrals. As a physical application we show that periodic kink solutions (kink chains) of the double sine-Gordon model can be described in a canonical form in terms of generalized Jacobi functions.Comment: 18 pages, 9 figures, 3 table

On the basic mechanism of Pixelized Photon Detectors

A Pixelized Photon Detector (PPD) is a generic name for the semiconductor devices operated in the Geiger-mode, such as Silicon PhotoMultiplier and Multi-Pixel Photon Counter, which has high photon counting capability. While the internal mechanisms of the PPD have been intensively studied in recent years, the existing models do not include the avalanche process. We have simulated the multiplication and quenching of the avalanche process and have succeeded in reproducing the output waveform of the PPD. Furthermore our model predicts the existence of dead-time in the PPD which has never been numerically predicted. For serching the dead-time, we also have developed waveform analysis method using deconvolution which has the potential to distinguish neibouring pulses precisely. In this paper, we discuss our improved model and waveform analysis method.Comment: 4pages, 5figures, To appear in the proceedings of 5th International Conference on New Developments in Photodetection (NDIP08), Aix-les-Bains, France, 15-20 Jun 200

Formal Proof of SCHUR Conjugate Function

The main goal of our work is to formally prove the correctness of the key commands of the SCHUR software, an interactive program for calculating with characters of Lie groups and symmetric functions. The core of the computations relies on enumeration and manipulation of combinatorial structures. As a first "proof of concept", we present a formal proof of the conjugate function, written in C. This function computes the conjugate of an integer partition. To formally prove this program, we use the Frama-C software. It allows us to annotate C functions and to generate proof obligations, which are proved using several automated theorem provers. In this paper, we also draw on methodology, discussing on how to formally prove this kind of program.Comment: To appear in CALCULEMUS 201

InAs quantum dots grown on the GaAs(113)A and GaAs(-1-1-3)B surfaces: A comparative STM study

InAs quantum dots (QD's) were grown on GaAs(113)A and GaAs((1) over bar(1) over bar(3) over bar )B substrates by molecular-beam epitaxy. Atomically resolved scanning tunneling microscopy images acquired in situ from uncapped samples reveal the shape of the QD's including the atomic structure of their main bounding facets. On the (113)A substrate the QD's are elongated along [33 (2) over bar] with a wide size distribution, whereas on ((1) over bar(1) over bar(3) over bar )B they are rather round and exhibit a more uniform size distribution. These observations are related to the different morphology of the substrates before QD formation. The differences in shape, size, and size distribution are discussed in terms of facet growth kinetics

From Lagrangian to Quantum Mechanics with Symmetries

We present an old and regretfully forgotten method by Jacobi which allows one to find many Lagrangians of simple classical models and also of nonconservative systems. We underline that the knowledge of Lie symmetries generates Jacobi last multipliers and each of the latter yields a Lagrangian. Then it is shown that Noether's theorem can identify among those Lagrangians the physical Lagrangian(s) that will successfully lead to quantization. The preservation of the Noether symmetries as Lie symmetries of the corresponding Schr\"odinger equation is the key that takes classical mechanics into quantum mechanics. Some examples are presented.Comment: To appear in: Proceedings of Symmetries in Science XV, Journal of Physics: Conference Series, (2012

A Comparison of Faculty Perceptions of University Technology Transfer by Level of Institutional Success in the Technology Transfer Process.

The purpose of this study was to gather information concerning faculty perceptions of university technology transfer and to compare the perceptions of faculty towards university involvement in technology transfer activities by the relative success of the institutions in technology transfer. The objectives were to describe selected faculty at two land grant universities in the southern portion of the United States. The study was designed to describe faculty based on certain personal, professional, and demographic characteristics, and to compare faculty at an institution defined as successful in technology transfer and an institution that is relatively unsuccessful on certain selected measures. Participants\u27 responses to a researcher-designed survey instrument indicated that there were many similarities across the institutions, both in faculty demographics and in faculty perception of their university\u27s policies and practices in the area of technology transfer. In fact, only one significant demographic difference between the respondents of the two universities was noted. Respondents from the more successful institution in the area of technology transfer had a significantly higher likelihood of having received competitive grant funding within the last three years. All other demographic factors were found to be independent of the institutional affiliation of the faculty member. When reviewing the findings regarding faculty perceptions and institutional affiliation, no significant difference was found between universities on the mean rankings of the importance of technology transfer office functions. However, the universities\u27 respondents differed significantly in their responses to the question of institutional success at technology transfer. Faculty in the more successful institution responded more favorably to the survey items regarding institutional success in technology transfer and faculty in the less successful institution responded less favorably to the same items