Formation of new oxide glasses by laser spin melting and free fall cooling

Glass spherules have been made by laser spin melting and free fall cooling techniques from ceramic rods. Thus, the materials were not in contact with a container at any time. Glasses of 100 to 800 μm diameter were formed from at least 80 wt% of the oxides Al₂O₃, Ga₂O₃, In₂O₃, La₂O₃, ZrO₂, HfO₂, Nb₂O₅ and Ta₂O₅ with 20 or less weight percent of CaO + SiO₂. The best glass formers were in the Nb₂O₅- and Ta₂O₅-based systems. The indices of refraction of most of the glasses and Abbe numbers of many were measured.     

Effect of Ylang-Ylang (Cananga odorata Hook. F. & Thomson) Essential Oil on Acute Inflammatory Response In Vitro and In Vivo

The aim of this study is to evaluate the phytochemical profile, oral acute toxicity, and the effect of ylang-ylang (Cananga odorata Hook. F. & Thomson) essential oil (YEO) on acute inflammation. YEO was analyzed by gas chromatography/mass spectrometry. For in vitro tests, YEO was assessed using cytotoxicity, neutrophil chemotaxis induced by N-formyl methionyl leucyl phenylalanine (fMLP), and phagocytic activity tests. YEO was orally administered in zymosan-induced peritonitis, carrageenan-induced leukocyte rolling, and adhesion events in the in situ microcirculation model and in carrageenan-induced paw edema models. YEO (2000 mg/kg) was also tested using an acute toxicity test in Swiss mice. YEO showed a predominance of benzyl acetate, linalool, benzyl benzoate, and methyl benzoate. YEO did not present in vitro cytotoxicity. YEO reduced the in vitro neutrophil chemotaxis induced by fMLP and reduced the phagocytic activity. The oral treatment with YEO reduced the leukocyte recruitment and nitric oxide production in the zymosan-induced peritonitis model, reduced rolling and adherent leukocyte number induced by carrageenan in the in situ microcirculation model, and reduced carrageenan-induced edema and mechanical hyperalgesia. YEO did not present signs of toxicity in the acute toxicity test. In conclusion, YEO affected the leukocyte activation, and presented antiedematogenic, anti-hyperalgesic, and anti-inflammatory properties.     

Active noise control in finite length ducts

A simple technique for the active control of sound in ducts, initially suggested by Olson and May [1], is investigated in detail. A simple, “virtual earth” principle, feedback loop is used to drive the sound pressure to a minimum at a microphone placed close to a loudspeaker in the duct wall. This produces a reflection of downstream travelling plane waves. A detailed investigation of the loudspeaker near field has enabled the optimum position of the microphone to be identified. The system is shown to be especially effective at the frequencies of the longitudinal duct resonances, where the acoustic response of the duct produces a high loop gain. Results are presented which show a reduction of up to 20 dB in the amplitude of low frequency broadband noise at a position downstream of the cancelling source.     

Errors in two-point sound reproduction

This paper deals with the problem of reproducing two signals at two points in space by using two acoustic sources. While much is now known about the techniques available for the design of matrices of inverse filters that enable this objective to be achieved in practice, it is still the basic physics of the sound field produced that controls the effectiveness of such systems and which ultimately dictates their design. The basic physical processes involved in producing the cross-talk cancellation that enables the reproduction of the desired signals is revisited here by using a simple two source/two field point free field model. The singular value decomposition is used to identify those frequencies where the inversion problem becomes ill-conditioned and to explain physically the origin of the ill-conditioning. As observed previously, it is found that cross-talk cancellation becomes problematic when the path length difference between the two sources and one of the field points becomes equal to one half the acoustic wavelength. The ill-conditioned frequencies are also found to be associated with a limited spatial region of cross-talk cancellation and with large source outputs manifested in the time domain by responses of long duration.