I Want My Mamma

https://digitalcommons.library.umaine.edu/mmb-vp/6032/thumbnail.jp

I Long To See The Old Home Once Again

https://digitalcommons.library.umaine.edu/mmb-vp/3793/thumbnail.jp

Gender and vocal production mode discrimination using the high frequencies for speech and singing

Humans routinely produce acoustical energy at frequencies above 6 kHz during vocalization, but this frequency range is often not represented in communication devices and speech perception research. Recent advancements toward high-definition (HD) voice and extended bandwidth hearing aids have increased the interest in the high frequencies. The potential perceptual information provided by high-frequency energy (HFE) is not well characterized. We found that humans can accomplish tasks of gender discrimination and vocal production mode discrimination (speech vs. singing) when presented with acoustic stimuli containing only HFE at both amplified and normal levels. Performance in these tasks was robust in the presence of low-frequency masking noise. No substantial learning effect was observed. Listeners also were able to identify the sung and spoken text (excerpts from “The Star-Spangled Banner”) with very few exposures. These results add to the increasing evidence that the high frequencies provide at least redundant information about the vocal signal, suggesting that its representation in communication devices (e.g., cell phones, hearing aids, and cochlear implants) and speech/voice synthesizers could improve these devices and benefit normal-hearing and hearing-impaired listeners

The perceptual significance of high-frequency energy in the human voice

While human vocalizations generate acoustical energy at frequencies up to (and beyond) 20 kHz, the energy at frequencies above about 5 kHz has traditionally been neglected in speech perception research. The intent of this paper is to review (1) the historical reasons for this research trend and (2) the work that continues to elucidate the perceptual significance of high-frequency energy (HFE) in speech and singing. The historical and physical factors reveal that, while HFE was believed to be unnecessary and/or impractical for applications of interest, it was never shown to be perceptually insignificant. Rather, the main causes for focus on low-frequency energy appear to be because the low-frequency portion of the speech spectrum was seen to be sufficient (from a perceptual standpoint), or the difficulty of HFE research was too great to be justifiable (from a technological standpoint). The advancement of technology continues to overcome concerns stemming from the latter reason. Likewise, advances in our understanding of the perceptual effects of HFE now cast doubt on the first cause. Emerging evidence indicates that HFE plays a more significant role than previously believed, and should thus be considered in speech and voice perception research, especially in research involving children and the hearing impaired

Mechanical and Combustion Performance of Multi-Walled Carbon Nanotubes as an Additive to Paraffin-Based Solid Fuels for Hybrid Rockets

Paraffin-based solid fuels for hybrid rocket motor applications are recognized as a fastburning alternative to other fuel binders such as HTPB, but efforts to further improve the burning rate and mechanical properties of paraffin are still necessary. One approach that is considered in this study is to use multi-walled carbon nanotubes (MWNT) as an additive to paraffin wax. Carbon nanotubes provide increased electrical and thermal conductivity to the solid-fuel grains to which they are added, which can improve the mass burning rate. Furthermore, the addition of ultra-fine aluminum particles to the paraffin/MWNT fuel grains can enhance regression rate of the solid fuel and the density impulse of the hybrid rocket. The multi-walled carbon nanotubes also present the possibility of greatly improving the mechanical properties (e.g., tensile strength) of the paraffin-based solid-fuel grains. For casting these solid-fuel grains, various percentages of MWNT and aluminum particles will be added to the paraffin wax. Previous work has been published about the dispersion and mixing of carbon nanotubes.1 Another manufacturing method has been used for mixing the MWNT with a phenolic resin for ablative applications, and the manufacturing and mixing processes are well-documented in the literature.2 The cost of MWNT is a small fraction of single-walled nanotubes. This is a scale-up advantage as future applications and projects will require low cost additives to maintain cost effectiveness. Testing of the solid-fuel grains will be conducted in several steps. Dog bone samples will be cast and prepared for tensile testing. The fuel samples will also be analyzed using thermogravimetric analysis and a high-resolution scanning electron microscope (SEM). The SEM will allow for examination of the solid fuel grain for uniformity and consistency. The paraffin-based fuel grains will also be tested using two hybrid rocket test motors located at the Pennsylvania State University s High Pressure Combustion Lab

Principles behind evaluations of national food and beverage taxes and other regulatory efforts

Non-PRIFPRI3; ISIPHN

Akustičko–mehanički model govornog trakta

Modelling voice tract using an acoustical–mechanical analogy is shown in this article. The process of modelling voice tract is often reduced to one-dimensional acoustical model, i.e. planar waveguide model. With this acousticalmechanical model, computer programs are utilized to analyze and synthesize the voice tract. Hence, it is possible to calculate models which describe the voice tract with satisfactory quality and detail level and these models can be used in practice and applied to particular cases. In this article the process of producing a voice tract model is presented. The process includes the usage of three different computer programs, each of them dedicated to one segment of modelling. Recordings for three speakers were made and the analysis of voice parameters was performed. After the analysis is completed, a two-dimensional model of the voice tract was made, which resulted in a mechanical model consisting of specific number of tubes. Finally, the evaluation procedure for the model is done by applying a software developed specifically for this purpose, in order to determine whether the resulting model truly represents the voice tract of each speaker.Ovaj članak daje primjer izrade modela govornog trakta zasnovanog na akustičko-mehaničkim analogijama, za tri govornika, pomoću računalno zasnovanog sustava. Definiranje modela govornog trakta često se svodi na jednodimenzionalni akustički model, planarni valovodni model. Kad je napravljen akustičko-mehanički model, u analizu i sintezu uvode se računala i računalni programi. Pomoću njih se dobivaju modeli i izračuni koji sa zadovoljavajućom kvalitetom i preciznošću opisuju govorni trakt, pa takve modele možemo koristiti u praksi i primjenjivati na konkretne slučajeve. U članku su za dobivanje modela govornog trakta korištene tri različite programske podrške, svaka u svom segmentu izrade modela. Snimljena su tri govornika i napravljena je analiza glasa. Nakon toga je, opet koristeći računalo, izmodeliran dvodimenzionalni model govornog trakta, koji kao rezultat daje mehanički model s odre.enim brojem cjevčica. Na kraju je napravljena provjera tog modela sa programskom podrškom koja je napisana za tu svrhu, kako bi se utvrdilo da dobiveni model zaista predstavlja govorni trakt pojedinog govornika

Interlayer coupling in ferromagnetic semiconductor superlattices

We develop a mean-field theory of carrier-induced ferromagnetism in diluted magnetic semiconductors. Our approach represents an improvement over standard RKKY model allowing spatial inhomogeneity of the system, free-carrier spin polarization, finite temperature, and free-carrier exchange and correlation to be accounted for self-consistently. As an example, we calculate the electronic structure of a Mn$_x$Ga$_{1-x}$As/GaAs superlattice with alternating ferromagnetic and paramagnetic layers and demonstrate the possibility of semiconductor magnetoresistance systems with designed properties.Comment: 4 pages, 4 figure

Theory of Magnetic Properties and Spin-Wave Dispersion for Ferromagnetic (Ga,Mn)As

We present a microscopic theory of the long-wavelength magnetic properties of the ferromagnetic diluted magnetic semiconductor (Ga,Mn)As. Details of the host semiconductor band structure, described by a six-band Kohn-Luttinger Hamiltonian, are taken into account. We relate our quantum-mechanical calculation to the classical micromagnetic energy functional and determine anisotropy energies and exchange constants. We find that the exchange constant is substantially enhanced compared to the case of a parabolic heavy-hole-band model.Comment: 9 pages, 4 figure