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Wyszukujesz frazę "Ramos, O." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Magnitude Modelling of HRTF Using Principal Component Analysis Applied to Complex Values
Autorzy:
Ramos, O. A.
Tommasini, F. C.
Powiązania:
https://bibliotekanauki.pl/articles/177682.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
head related transfer functions
HRTF
principal components analysis
PCA
binaural audition
auditory perception
Opis:
Principal components analysis (PCA) is frequently used for modelling the magnitude of the head- related transfer functions (HRTFs). Assuming that the HRTFs are minimum phase systems, the phase is obtained from the Hilbert transform of the log-magnitude. In recent years, the PCA applied to HRTFs is also used to model individual HRTFs relating the PCA weights with anthropometric measurements of the head, torso and pinnae. The HRTF log-magnitude is the most used format of input data to the PCA, but it has been shown that if the input data is HRTF linear magnitude, the cumulative variance converges faster, and the mean square error (MSE) is smaller. This study demonstrates that PCA applied directly on HRTF complex values is even better than the two formats mentioned above, that is, the MSE is the smallest and the cumulative variance converges faster after the 8th principal component. Different objective experiments around all the median plane put in evidence the differences which, although small, seem to be perceptually detectable. To elucidate this point, psychoacoustic discrimination tests are done between measured and reconstructed HRTFs from the three types of input data mentioned, in the median plane between −45◦ and +90◦.
Źródło:
Archives of Acoustics; 2014, 39, 4; 477-482
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of seawater main components on frothability in the flotation of Cu-Mo sulfide ore
Autorzy:
Laskowski, J. S.
Castro, S.
Ramos, O.
Powiązania:
https://bibliotekanauki.pl/articles/109747.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
seawater
froth stability
Cu-Mo flotation
magnesium ions
molybdenite flotation
Opis:
The main problem in the flotation of Cu-Mo sulfide ores in seawater is poor floatability of molybdenite at pH>9.5. Froth stability plays a very important role in determining concentrate grade and recovery in flotation operations and in this paper both floatability and frothability have been tested. The frothability have been studied by measuring froth equilibrium layer thickness in a modified laboratory flotation cell. Two chemical aspects of seawater need to be considered: the content of NaCl (around 87% of salinity), and the concentration of secondary ions (around 13%) (sulfate, magnesium, calcium, bicarbonate ions, etc.). Seawater, NaCl solutions, and seawater’s ions were found to depress frothability. The effect of pH on frothability over the pH range from 9.5 to 11, which is very strong in freshwater, becomes negligible in seawater and the tested electrolyte solutions. The analysis of the relationship between the mechanisms of molybdenite depression and the loss of frothability in seawater implies that the effects of the studied ions on molybdenite floatability and on pulp frothability are different. While depression of molybdenite floatability could be tracked down to magnesium hydroxide precipitation as a main culprit, the depression of frothability is a much more complicated issue.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 17-29
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of the physicochemical, performance, and consumer-information characteristics of commercial nonmedicated shampoo for dogs
Autorzy:
Peña-Corona, S.I.
Juárez-Rodríguez, I.
Vargas-Estrada, D.
Amador-González, E.
Arvizu-Tovar, L.
Soberanis-Ramos, O.
Powiązania:
https://bibliotekanauki.pl/articles/16539147.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
veterinary shampoo
quality control
sensory evaluation
performance evaluation
label
animal welfare
dog bath
Opis:
The aim was to analyze the quality of commercial shampoo without prophylactic effect for dogs. The analysis was based on the evaluations and requirements established for human-line products since there is no guide for veterinary products in Mexico; such evaluations have not been carried out or published in Mexico. Physicochemical, sensory, performance, and consumer information tests of the shampoo were carried out. The sample consisted of twenty products marketed in Mexico City. During the evaluation of the label, a serious non-compliance with applicable regulations was found. The pH of the products ranged between 5.6 and 8.4; Significant differences (p<0.05) were found between the three groups with low (6.1), medium (7.2), and high (8.1) pH. Viscosity values were from 1131 to 3102. For the foam index, no statistically significant differences were found. 100% of the products analyzed complied with the rest of the quality tests carried out. The results of the quality analysis in this study will allow veterinarians specializing in small species to better select and recommend the products for their use and inform dog owners, about the safety, and value of the products.
Źródło:
Polish Journal of Veterinary Sciences; 2022, 25, 2; 213-221
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of air profiling and frother concentration on a flotation bank performance
Autorzy:
Maldonado, Miguel
Ramos, Ignacio
Pinto, Alonso
Gomez, Cesar O.
Powiązania:
https://bibliotekanauki.pl/articles/29596463.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation banks
air profiling
frother
Opis:
The impact of air distribution on the metallurgical performance of a flotation bank operating with a mineral slurry having a moderate and high frother concentration is assessed. A flotation bank of two and three 5L Denver cells was implemented, and air flow was distributed down the bank as increasing and decreasing profiles. It was observed that when operating the bank configurations with a moderate frother concentration (10 ppm DF 400) the increasing profile provided the highest Cu enrichment ratio at the expense of a slight reduction in Cu recovery. This increase in selectivity was mainly due to a significant reduction in the water recovery and mass-pull in the first cell. When the bank operated with a high frother concentration, i.e., well beyond the CCC, a significant increase in water recovery was observed, producing a significant loss in selectivity that could not be compensated by air profiling.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 186274
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined Analyses of Ion Beam Synthesized Layers in Porous Silicon
Autorzy:
Ramos, A. R.
Pászti, F.
Horváth, Z. E.
Vázsonyi, É.
Conde, O.
da Silva, M. F.
da Silva, M. R.
Soares, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/2028988.pdf
Data publikacji:
2001-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
61.18.Bn
61.43.Gt
68.55.Ln
Opis:
High dose ion implantation was used to form polycrystalline silicide films on porous silicon with different native concentrations of light impurities (C and O). Porous silicon layers severalμm thick were implanted with 170 keV Cr$\text{}^{+}$ ions to fluences of 3×10$\text{}^{17}$ ions/cm$\text{}^{2}$ both at room temperature and 450ºC. Similar samples were implanted with 100 keV Co$\text{}^{+}$ ions to fluences of 2×10$\text{}^{17}$ ions/cm$\text{}^{2}$ at room temperature, 350ºC, and 450ºC. The formed silicide compounds were studied by Rutherford backscattering spectrometry, elastic recoil detection, glancing incidence X-ray diffraction, and four point-probe sheet resistance measurements. Selected Co implanted samples were analysed by cross-section transmission electron microscopy. Results show that the light impurities were partially expelled from the forming silicide layer. Combining cross-section transmission electron microscopy with ion beam methods it was possible to show that, in the implanted region, the porous structure collapses and densifies during implantation, but the underlying porous silicon remains intact. The layer structure, as well as the quality and type of the formed silicide, were found to depend on the original impurity level, implantation temperature, and annealing.
Źródło:
Acta Physica Polonica A; 2001, 100, 5; 773-780
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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