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Multiple scattering contribution to trabecular bone backscatter

100%

Wójcik J. , Litniewski J. , Nowicki A.

2009

tom Vol. 12

227-236

Integral equations that describe scattering on the structure with step rise parameters, have been numerically solved on example of the trabecular bone model. The model consists of several hundred elements with randomly selected parameters. The spectral distribution of scatter coefficients in subsequent orders of scattering has been presented.

Community annoyance from aircraft induced noise in Delhi

88%

Sanyogita , Kumar K. , Jain V. K.

Archives of Acoustics

2007

tom Vol. 32, No. 2

367-375

Air traffic noise is a major cause of community annoyance in the residential areas near airports. The present study has been prompted by the need to examine the noise levels induced by the increased air traffic in Delhi in recent years. Noise levels have been measured in the indoor environment of two prominent residential areas of Delhi, namely, University Campus (UC) and Vasant Vihar (VV) which lie underneath the landing flight path of aircraft in Delhi. Spectral distributions show higher noise levels at lower frequencies and exhibit a declining trend with increase in frequency. With the help of spectral information, an index of aircraft noise, PNdB (perceived noise levels in decibels) is determined to assess relative annoyance or noisiness felt by the community of residential areas. PNdB values in the case of UC vary from a minimum of 66.7 to a maximum of 85.2. Further down the landing path, PNdB levels at VV are found to be appreciably higher in the range of 76.18-91.37. Results of social survey conducted to assess the community response to aircraft noise reveal that a majority (73%) of the respondents experience moderate to extreme annoyance. This is in conformity with the rather high PNdB values obtained for both the residential areas.

Underwater light field and spectral distribution of attenuation depth in inland and coastal waters

63%

Kauer T. , Arst H. , Tuvikene L.

Oceanologia

2010

tom 52

nr 2

155-170

The daily variations in the underwater irradiance spectra at different depths were determined using a combination of in situ data and model calculations. The spectra of the attenuation depth (relevant in optical remote sensing) were derived from these data. The results are presented for four Estonian lakes (Koorküla Valgjärv, Võrtsjärv, Harku, and Peipsi) and for coastal waters of the Baltic Sea (Pärnu Bay, Gulf of Riga).

Bilans energetyczny źródeł światła - problemy pomiarowe

63%

Grzonkowski J.

tom nr 2

10--11

Porównanie modelowanych oraz rzeczywistych wartości parametrów świetlnych i kolorymetrycznych białych diod LED pracujących w szerokim zakresie temperatur

63%

Listowski M.

Przegląd Elektrotechniczny

2022

tom R. 98, nr 6

57--61

Z powodu czasochłonności oraz kosztochłonności, jakiej wymaga przeprowadzanie pomiarów rozkładów widmowych (SPD) LED-ów pracujących w różnych temperaturach, pożądanym jest możliwość zamodelowania tych pomiarów w szerokim zakresie temperatur pracy. Bazując na modelowaniu SPD białych LED-ów metodą superpozycji Gaussa przeprowadzono analizę dokładności tej metody w wyznaczaniu ich parametrów fotometrycznych oraz kolorymetrycznych dla różnych temperatur pracy. Wykazano, że wartości parametrów świetlnych dla rozkładu zmierzonego oraz odtworzonego tym modelem są zgodne.

Because of the time- and cost- intensive nature of making spectral distribution (SPD) measurements of LEDs operating at different temperatures, it is desirable to be able to model these measurements over a wide range of operating temperatures. Based on the SPD modeling of white LEDs by the Gauss superposition method, an analysis of the accuracy of this method in determining their photometric and colorimetric parameters for different operating temperatures was conducted. It was shown that the values of light parameters for the distribution measured and modeled by this model are consistent.

Influence of underwater light fields on pigment characteristics in the Baltic Sea – results of statistical analysis

51%

Ston-Egiert J. , Majchrowski R. , Darecki M. , Kosakowska A. , Ostrowska M.

Oceanologia

2012

tom 54

nr 1