Acoustic Simulation of a Special Switched Reluctance Drive by Means of Field-Circuit Coupling and Multiphysics Simulation

The approach presented in this paper consists of an energy-based field-circuit coupling in combination with multi-physics simulation of the acoustic radiation of electrical machines. The proposed method is applied to a special switched reluctance motor with asymmetric pole geometry to improve the start-up torque. The pole shape has been optimized, subject to low torque ripple, in a previous study. The proposed approach here is used to analyze the impact of the optimization on the overall acoustic behavior. The field-circuit coupling is based on a temporary lumped-parameter model of the magnetic part incorporated into a circuit simulation based on the modified nodal analysis. The harmonic force excitation is calculated by means of stress tensor computation, and it is transformed to a mechanical mesh by mapping techniques. The structural dynamic problem is solved in the frequency domain using a finite-element modal analysis and superposition. The radiation characteristic is obtained from boundary element acoustic simulation. Simulation results of both rotor types are compared, and measurements of the drive are presented.

An Alternative Optical Method for Acoustic Resonance Detection in HID Lamps

Acoustic resonances are observed in high-pressure discharge lamps operated with ac input modulated power frequencies in the kilohertz range. This paper describes an optical resonance detection method for high-intensity discharge lamps using computer-controlled cameras and image processing software. Experimental results showing acoustic resonances in high-pressure sodium lamps are presented.

Matrix Method for Acoustic Levitation Simulation

A matrix method is presented for simulating acoustic levitators. A typical acoustic levitator consists of an ultrasonic transducer and a reflector. The matrix method is used to determine the potential for acoustic radiation force that acts on a small sphere in the standing wave field produced by the levitator. The method is based on the Rayleigh integral and it takes into account the multiple reflections that occur between the transducer and the reflector. The potential for acoustic radiation force obtained by the matrix method is validated by comparing the matrix method results with those obtained by the finite element method when using an axisymmetric model of a single-axis acoustic levitator. After validation, the method is applied in the simulation of a noncontact manipulation system consisting of two 37.9-kHz Langevin-type transducers and a plane reflector. The manipulation system allows control of the horizontal position of a small levitated sphere from -6 mm to 6 mm, which is done by changing the phase difference between the two transducers. The horizontal position of the sphere predicted by the matrix method agrees with the horizontal positions measured experimentally with a charge-coupled device camera. The main advantage of the matrix method is that it allows simulation of non-symmetric acoustic levitators without requiring much computational effort.

Finite Element Analysis and Optimization of a Single-Axis Acoustic Levitator

A finite element analysis and a parametric optimization of single-axis acoustic levitators are presented. The finite element method is used to simulate a levitator consisting of a Langevin ultrasonic transducer with a plane radiating surface and a plane reflector. The transducer electrical impedance, the transducer face displacement, and the acoustic radiation potential that acts on small spheres are determined by the finite element method. The numerical electrical impedance is compared with that acquired experimentally by an impedance analyzer, and the predicted displacement is compared with that obtained by a fiber-optic vibration sensor. The numerical acoustic radiation potential is verified experimentally by placing small spheres in the levitator. The same procedure is used to optimize a levitator consisting of a curved reflector and a concave-faced transducer. The numerical results show that the acoustic radiation force in the new levitator is enhanced 604 times compared with the levitator consisting of a plane transducer and a plane reflector. The optimized levitator is able to levitate 3, 2.5-mm diameter steel spheres with a power consumption of only 0.9 W.

Signals in Communication Engineering History

This paper is a study of various electric signals, which have been employed throughout the history of communication engineering in its two main landmarks: the telegraph and the telephone. The signals are presented in their time and frequency domain representations. The historical order has been followed in the presentation: wired systems, spark gap wireless, continuous wave (CW) and amplitude modulation (AM), detection by rectification, and frequency modulation (FM). The analysis of these signals is meant to lead into a better understanding of the evolution of communication technology. The material presented in this work could be used to illustrate ""Signals and Systems"" and ""Communication Systems"" courses by taking advantage of its technical as well as historical contents.

Fast Transforms for Acoustic Imaging-Part I: Theory

The classical approach for acoustic imaging consists of beamforming, and produces the source distribution of interest convolved with the array point spread function. This convolution smears the image of interest, significantly reducing its effective resolution. Deconvolution methods have been proposed to enhance acoustic images and have produced significant improvements. Other proposals involve covariance fitting techniques, which avoid deconvolution altogether. However, in their traditional presentation, these enhanced reconstruction methods have very high computational costs, mostly because they have no means of efficiently transforming back and forth between a hypothetical image and the measured data. In this paper, we propose the Kronecker Array Transform ( KAT), a fast separable transform for array imaging applications. Under the assumption of a separable array, it enables the acceleration of imaging techniques by several orders of magnitude with respect to the fastest previously available methods, and enables the use of state-of-the-art regularized least-squares solvers. Using the KAT, one can reconstruct images with higher resolutions than was previously possible and use more accurate reconstruction techniques, opening new and exciting possibilities for acoustic imaging.

Fast Transforms for Acoustic Imaging-Part II: Applications

In Part I [""Fast Transforms for Acoustic Imaging-Part I: Theory,"" IEEE TRANSACTIONS ON IMAGE PROCESSING], we introduced the Kronecker array transform (KAT), a fast transform for imaging with separable arrays. Given a source distribution, the KAT produces the spectral matrix which would be measured by a separable sensor array. In Part II, we establish connections between the KAT, beamforming and 2-D convolutions, and show how these results can be used to accelerate classical and state of the art array imaging algorithms. We also propose using the KAT to accelerate general purpose regularized least-squares solvers. Using this approach, we avoid ill-conditioned deconvolution steps and obtain more accurate reconstructions than previously possible, while maintaining low computational costs. We also show how the KAT performs when imaging near-field source distributions, and illustrate the trade-off between accuracy and computational complexity. Finally, we show that separable designs can deliver accuracy competitive with multi-arm logarithmic spiral geometries, while having the computational advantages of the KAT.

Short communication: An evaluation of the effectiveness of Lactobacillus buchneri 40788 to alter fermentation and improve the aerobic stability of corn silage in farm silos

The objective of this study was to determine if the effects of inoculation with Lactobacillus buchneri 40788 were detectable when applied to whole-plant corn stored in farm silos. Corn silage was randomly sampled from farms in Wisconsin, Minnesota, and Pennsylvania, and was untreated (n = 15) or treated with an inoculant (n = 16) containing L. buchneri 40788 alone or this organism combined with Pediococcus pentosaceus during May and June 2007. Corn silage that was removed from the silo face during the morning feeding was sampled, vacuum-packed, and heat sealed in polyethylene bags and shipped immediately to the University of Delaware for analyses. Silage samples were analyzed for dry matter (DM), nutrient composition, fermentation end-products, aerobic stability, and microbial populations. The population of L. buchneri in silages was determined using a real-time quantitative PCR method. Aerobic stability was measured as the time after exposure to air that it took for a 2 degrees C increase above an ambient temperature. The DM and concentrations of lactic and acetic acids were 35.6 and 34.5, 4.17 and 4.85, and 2.24 and 2.41%, respectively, for untreated and inoculated silages and were not different between treatments. The concentration of 1,2-propanediol was greater in inoculated silages (1.26 vs. 0.29%). Numbers of lactic acid bacteria determined on selective agar were not different between treatments. However, the numbers of L. buchneri based on measurements using real-time quantitative PCR analysis were greater and averaged 6.46 log cfu-equivalents/g compared with 4.89 log cfu-equivalent for inoculated silages. There were fewer yeasts and aerobic stability was greater in inoculated silages (4.75 log cfu/g and 74 h of stability) than in untreated silages (5.55 log cfu/g and 46 h of stability). This study supports the effectiveness of L. buchneri 40788 on dairy farms.

Short communication: Evaluation of an on-farm test to estimate somatic cell count

The objective of this study was to compare the results of an on-farm test, named Somaticell, with results of electronic cell counting and for milk somatic cell count (SCC) among readers. The Somaticell test correctly determined the SCC in fresh quarter milk samples. Correlation between Somaticell and electronic enumeration of somatic cells was 0.92 and. coefficient 0.82. Using a threshold of 205,000 cells/mL, the sensitivity and specificity for determination of intramammary infections were 91.3 and 96.0%, respectively. The SCC was greater for milk samples from which major mastitis pathogens were recovered. Minor variation among readers was observed and most likely associated with the mixing procedure. However, the final analysis indicated that this variation was not significant and did not affect the amount of samples classified as having subclinical mastitis. The on-farm test evaluated in this study showed adequate capacity of determining SCC on quarter milk samples and may be considered as an alternative for on-farm detection of subclinical mastitis.

INVESTIGATION OF ACOUSTIC SIGNALS AS A TOOL FOR CHARACTERIZING SPOUTED BED DYNAMICS

The feasibility of characterizing the dynamics of a spouted bed based on acoustic emission (AE) signals is evaluated. Acoustic emission signals were measured in a semi-cylindrical Plexiglas column of diameter 150 mm and height 1000 mm with a conical base of internal angle 60 degrees and 25 mm inlet orifice diameter. Data were obtained for U/U(ms), from 0.3 to 2.0, static bed height from 250 to 500 mm, and glass beads of diameter 1.2 and 2.4 mm. AE signals reflected the effects of particle size and U/U(ms), but in general were insensitive to bed depth, even when there were drastic changes in spouting flow patterns. The results indicate that the AE signals were insensitive to the spouted bed hydrodynamics for the conditions studied. Overall, it appears that the AE analysis is unlikely to be a suitable technique for discriminating spouted bed flow regimes, at least for the range of frequencies and operating conditions investigated.

Early Effects on T lymphocyte Response to Iron Deficiency in Mice. Short Communication

Iron deficiency is a common nutritional disorder, affecting about 30% of the world population. Deficits in iron functional compartments have suppressive effects on the immune system. Environmental problems, age, and other nutrient deficiencies are some of the situations which make human studies difficult and warrant the use of animal models. This study aimed to investigate alterations in the immune system by inducing iron deficiency and promoting recuperation in a mouse model. Hemoglobin concentration, hematocrit, liver iron store, and flow cytometry analyses of cell-surface transferrin receptor (CD71) on peripheral blood and spleen CD4+ and CD8+ T lymphocyte were performed in the control (C) and the iron-deficient (ID) groups of animals at the beginning and end of the experiment. Hematological indices of C and ID mice were not different but the iron stores of ID mice were significantly reduced. Although T cell subsets were not altered, the percentage of T cells expressing CD71 was significantly increased by ID. The results suggest that iron deficiency induced by our experimental model would mimic the early events in the onset of anemia, where thymus atrophy is not enough to influence subset composition of T cells, which can still respond to iron deficiency by upregulating the expression of transferrin receptor.

Acoustic hypersensitivity in adult rats after neonatal ventral hippocampus lesions

Rats with a bilateral neonatal ventral hippocampus lesion (NVHL) are used as models of neurobiological aspects of schizophrenia. In view of their decreased number of GABAergic interneurons, we hypothesized that they would show increased reactivity to acoustic stimuli. We systematically characterized the acoustic reactivity of NVHL rats and sham operated controls. They were behaviourally observed during a loud white noise. A first cohort of 7 months` old rats was studied. Then the observations were reproduced in a second cohort of the same age after characterizing the reactivity of the same rats to dopaminergic drugs. A third cohort of rats was studied at 2, 3, 4, 5 and 6 months. In subsets of lesioned and control rats, inferior colliculus auditory evoked potentials were recorded. A significant proportion of rats (50-62%) showed aberrant audiogenic responses with explosive wild running resembling the initial phase of audiogenic seizures. This was not correlated with their well-known enhanced reactivity to dopaminergic drugs. The proportion of rats showing this strong reaction increased with rats` age. After the cessation of the noise, NVHL rats showed a long freezing period that did neither depend on the size of the lesion nor on the rats` age. The initial negative deflection of the auditory evoked potential was enhanced in the inferior colliculus of only NVHL rats that displayed wild running. Complementary anatomical investigations using X-ray scans in the living animal, and alizarin red staining of brain slices, revealed a thin layer of calcium deposit close to the medial geniculate nuclei in post-NVHL rats, raising the possibility that this may contribute to the hyper-reactivity to sounds seen in these animals. The findings of this study provide complementary information with potential relevance for the hyper-reactivity noted in patients with schizophrenia, and therefore a tool to investigate the underlying biology of this endophenotype. (C) 2009 Elsevier B.V. All rights reserved.

Enabling International Communication among Brazilian Occupational Therapists: Seeking Consensus on Occupational Terminology

The purpose of this study was to examine how key occupational therapy terminologies are used by Brazilian occupational therapists. A nominal group approach combined with a Delphi technique involving 31 Brazilian occupational therapists was applied. A sociolinguistic approach was adopted since it broadens our understanding of the social and cultural determinants of terminology consolidation. Brazilian occupational therapists were found to adopt the term activity more often than human action or doing. Even less often were praxis and occupation applied. No consensus was reached regarding which of the terms is most preferred. While Brazilian occupational therapists have been developing their profession from international standards, it is still embedded in local demands and policies. Additionally, the political context must be considered when building an international dialogue between members of a professional body. Such a dialogue could engage professionals from different countries in meaningful exchanges about their practices. These exchanges may lead to the development of solid professional communities that can contribute meaningfully to social change. Copyright (C) 2010 John Wiley & Sons, Ltd.

Validation of ASHA FACS-Functional Assessment of Communication Skills for Alzheimer Disease Population

This study vas aimed to validate the American Speech-Language-Hearing Association Functional Assessment Of Communication Skills (ASHA FACS) for a Brazilian population. The scale was translated and adapted into Portuguese. Thirty-two patients with mild Alzheimer disease (AD). 25 patients with moderate AD. and 51 elderly without dementia were examined with Mini Mental State Examination, Geriatric Depression Scale. and Alzheimer Disease Assessment Scale-Cognitive subscale (ADAS-cog). The ASHA FACS was answered by their relative/caregiver. The scale`s internal consistency. its inter-examiner and intra-examiner`s reproducibility. and scale`s criterion validity were researched by correlation with ADAS-cog,. The sensitivity and specificity Were also researched. Statistical analyses indicated that the ASHA FACS has excellent internal consistency (Cronbach alpha = 0.955), test-retest reliability (interclass correlation coefficient = 0.995; P < 0.001). and inter-examiners (interclass correlation coefficient = 0.998: P < 0.001). It showed excellent criterion validity when correlated with ADAS-cog,. The ASHA FACS scale showed good sensitivity (75.0%) and specificity (82.4%) values once it is an ecologic and broad evaluation. The ASHA FACS Portuguese version is a valid and reliable instrument to verify communication alterations in AD patients and fills an important gap of efficiency indicators for speech language therapy in our country.

Assessing deaf and hearing children`s communication in Brazil

In Brazil there are no specific tests for either signed or spoken language for deaf children. A protocol evaluating communicative abilities independent of modality of communication (sign language or spoken language), and comprising assessments of (a) pragmatic profile; (b) modality of communication and linguistic level; (c) complexity of communication; and (d) style and efficacy of communication between parent and child was administered to 127 deaf and hearing children. The children, aged 3-6 years old, were distributed in three groups: 20 with severe hearing loss, 40 with profound hearing loss and 67 normally hearing. Deaf children were found to be delayed, independent of their linguistic level and preferred modality of communication. The protocol in this study proved to be an useful instrument for gathering relevant information about the three groups of preschool children`s communicative abilities, and particularly suitable for use in countries where standardized assessments are not available. Learning outcomes: The reader will be introduced to the use of an assessment protocol comprising its development, application and data analysis. The reader will be informed about assessment of deaf children`s preferred modality of communication, by the participation of a bilingual (sign language user) professional. Communication abilities can be assessed independently of the linguistic modality. In developing countries in general, where simple and easy to administer assessments tools are scarce, such a protocol is of specific value. (c) 2010 Elsevier Inc. All rights reserved.