[Acoustic Levitation Methods and Apparatus]

Methods are described for acoustically levitating objects within chambers of spherical and cylindrical shape. The wavelengths for chambers of particular dimensions are given, for generating standing wave patterns of any of a variety of modes within the chambers. For a spherical chamber the lowest resonant mode is excited by applying a wavelength of 3.02R, where R is the chamber radius. The two lowest pure radial modes for that chamber, are excited by applying wavelengths of 1.40R and 0.814R. For a cylindrical chamber of radius R, the lowest mode is at a wavelength of 3.41R, and the lowest pure radial modes are at wavelengths of 1.64R and 0.896R

Simulating the Thermal Behavior an Earth-Stationed Satellite Terminal

Lumped parameter modeling using finite differencing, form the basis for a C language simulation of a thermal system. The study of the earth-stationed satellite terminal includes an introduction to the system, derivation of the governing equation, development of a simulation, and a comparison of the results to empirical data. The analysis is undertaken with emphasis on the worst-case thermal environment, and with determination of the cooling loads and transient response as primary goals. Comparing the predicted cooling loads to empirical data, and previous analyses, indicates an accurate simulation has been constructed. The computer models are offered as an alternative method in thermal design and analysis of electronic systems typical to the earth-stationed satellite terminal

The role of interference in metacognitive monitoring

Recent advancements in neuropsychology have initiated theoretical advancements in cognitive psychology, particularly concerning the constructs of interference and metacognition. These constructs share similar cognitive functioning and this study investigated the relationship between them. It was expected that students with higher monitoring ability would demonstrate lower susceptibility to interference. Students from undergraduate Educational Psychology classes were administered three tests: two measures of interference, and one measure of metacognitive monitoring ability. Variables from the Wisconsin Card Sort Test (WCST) and the Stroop Color and Word Test (SCWT) measured susceptibility to interference. A monitoring task applied to a math aptitude test was used to measure monitoring ability. Pearson-product correlations showed no relationship among the interference measures and monitoring ability. Furthermore, there was no relationship among the interference component: scores and monitoring ability. The results of this study are also inconsistent with previous research concerning monitoring and math score prediction. Results showed no difference between the monitoring and non-monitoring groups in ability to predict math scores

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

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

Nanoparticle Deposition by Boiling on Aluminum Surfaces to Enhance Wettability

Surface wettability is known to be important in boiling, condensation, frosting/defrosting, liquid desiccant flows in falling-film devices, and a myriad of other HVAC&R processes. Research has shown that surfaces treated with nanofluid boiling nanoparticle deposition exhibit radical changes in wettability, because a layer of nanoparticle coating is formed on the metal surface during microlayer evaporation at the base of the vapor bubble inboiling. Wettability is changed because surface chemical composition, surface roughness and porosity can be modified by the nanoparticle layer. This study is focused on how to manipulate wettability by nanoparticle deposition on aluminum surfaces, since this metal is commonly used as the material for heat transfer in air conditioning and refrigeration systems. The boiling deposition process occurs under atmospheric pressure, in a reservoir large compared to the sample size. The effect of nanoparticle concentration, boiling heat flux, boiling duration and surface initial roughness are studied by varying parameters one at a time while controlling the others. Al2O3 nanoparticles of an average size of 40nm are deposited on a 20mm x 20mm aluminum surface. After the surface is created, contact-angle measurements with water are conducted using a goniometer to measure the advancing, receding, and static contact angles so as to characterize the wetting behavior. The surface morphology is characterized through scanning electron microscopy (SEM) and profilometry. It is observed that the layer of Al2O3 nanoparticle deposited on aluminum surfaces enhances the wettability on the surface. This result is explained using Wenzel’s model, in which an increasing areal roughness factor leads to a decrease in the apparent contact angle. The boiling time ranges from five to thirty minutes. It is observed that the longer the boiling time the lower the contact water contact angle. The impact of surface contamination is also investigated, and it is shown that nanoparticle deposited surfaces manifest enhanced wettability superior to that of a bare aluminum surfaces even after exposure to laboratory air