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Optical properties of polyetherketoneketone based indirect dental restorations veneered with composite

Alsadon Omar, Wood Duncan, Patrick David, Durgesh Bangalore, Pollington Sarah

Polimery

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2022

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Vol. 67, nr 4

141--148

EN

In this study, the optical properties of indirect dental restorations based on polyetherketoneketone (PEKK), zirconia (YZ), and nickel-chromium (Ni-Cr) veneered with composite were compared. Based on the spectral reflectance, the CIE L*a*b* color coordinates, the color difference (ΔE), the opacity and the translucency parameter (TP) were determined using a spectrophotometer equipped with a D65 illuminant. The PEKK and Ni-Cr groups demonstrated similar CIE L*a*b* color values on white and black backgrounds. However, the zirconia group on a white backgrounds showed a slight shift in values towards red-yellow shades. The highest recorded ΔE values were 1.3 and 1.61 between PEKK and YZ groups, and Ni-Cr and YZ groups respectively. The opacity and translucency (TP) parameters were consistent with the spectral reflectance data, with the Ni-Cr and PEKK groups being completely opaque (100% and 0 TP). It has been shown that the use of the same indirect light-cured composite veneer with different substructure materials has no clinical effect on the esthetics of the final restoration.

PL

Porównano właściwości optyczne pośrednich uzupełnień protetycznych na bazie polieteroketonoketonu (PEKK), tlenku cyrkonu (YZ) i niklu-chromu (Ni-Cr) licowanych kompozytem. Na podstawie współczynnika odbicia spektralnego określono współrzędne koloru CIE L*a*b*, różnicę koloru (ΔE), nieprzezroczystość i parametr przezierności (TP). Współrzędne koloru grupy PEKK i Ni-Cr wykazywały podobne wartości koloru CIE L*a*b* na białym i czarnym tle. Natomiast w przypadku YZ na białym tle stwierdzono niewielkie przesunięcie wartości w kierunku odcieni czerwono-żółtych. Najwyższe odnotowane wartości ΔE wyniosły 1,3 i 1,61 odpowiednio dla grup PEKK i YZ oraz Ni-Cr i YZ. Parametry nieprzezroczystości i przezierności były zgodne z danymi spektralnego współczynnika odbicia, przy czym grupy Ni-Cr i PEKK były całkowicie nieprzezroczyste (100% i 0 TP). Wykazano, że zastosowanie tej samej pośredniej światłoutwardzalnej licówki kompozytowej z różnymi materiałami podbudowy nie ma klinicznego wpływu na estetykę ostatecznego uzupełnienia.

2

Reflectance spectra classification for the rapid assessment of water ecological quality in Mediterranean ports

Massi Luca, Maselli Fabio, Rossano Claudia, Gambineri Simone, Chatzinikolaou Evangelia, Dailianis Thanos, Arvanitidis Christos, Nuccio Caterina, Scapini Felicita, Lazzara Luigi

Oceanologia

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2019

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No. 61 (4)

445--459

EN

Ports are open systems with direct connection to the sea, therefore any potential impact on port waters may have implications for the health of adjacent marine ecosystems. European WFD addressed ports in the category of Heavily Modified Water Bodies (HMWBs) and promoted implementation of protocols to monitor and improve their ecological status. TRIX index, which incorporates the main variables involved in the trophism of marine ecosystems (Nitrogen, Phosphorus, Chlorophyll a, Dissolved Oxygen), is widely utilized in European coastal areas to evaluate trophic status. The relationships between the variables involved in TRIX computation, particularly Chlorophyll a concentration, and water spectral reflectance provides an alternative method to evaluate the quality and ecological status of the port water. Hyper-spectral (380-710 nm) water reflectance data were recorded by a portable radiometric system in five ports from the Western and Eastern Mediterranean Basin. The spectral distance between samples was measured by two metrics using both the original and reduced spectra and was implemented within a hierarchical clustering algorithm. The four spectral classes that emerged from this operation were statistically analysed versus standard water quality descriptors and phytoplankton community features to evaluate the ecological significance of the information obtained. The results indicated a substantial coherence of different indicators with more than 60% of the total TRIX variability is accounted for by the proposed classification of reflectance spectra. This classification is therefore proposed as a promising Rapid Assessment Technique of ports water ecological quality, which can serve as an effective monitoring tool for sustainable management of ports.

3

Ocena skuteczności modeli transferu promieniowania w badaniach stanu roślinności łąk

Jarocińska A.

Teledetekcja Środowiska

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2012

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T. 48

1--52

EN

Vegetation analysis is an important problem in regional and global scale. Because of pollution of environment and changes in the ecosystems plant monitoring is very important. Remote sensing data can be easily used to plant monitoring. That kind of method is much faster and more reliable than traditional approaches. Spectrometry analyzes the interactions between radiation and object and it uses measurement of radiation intensity as a function of wavelength. Each object emits and absorbs different quantity of radiation, so it is possible to recognise the object and check its characteristics analysing the spectrum. The subject of the researches is Polish meadows. The human usage of the meadows determines its proper functioning. Grasslands, which consist of meadows and pastures, cover 10% of Poland. Meadows are most extensively use. In Poland the crops from meadows (hay and green forage) are very low. The meadows in Poland are floristically and morphologically very diverse. Many factors influence on this ecosystem and that is why the monitoring is very important. The aim of the researches is to study the possibility of use of the Radiative Transfer Models in modelling the state of the heterogeneous vegetation cover of seminatural meadows in Poland. Two approaches are used to canopy analysis: statistical and modelling. In the statistic approach, biophysical parameters calculated from the image are correlated with reflectance or transmittance from fi eld measurements. In second approach physically based model is used to represent the photon transport inside leaves and canopy. The Radiative Transfer Models are based on the laws of optics. Developing the model results in better understanding of the interaction of light in canopy and leaves. The Radiative Transfer Models are often applied to vegetation modelling. The Radiative Transfer Models are physically based models which describe the interactions of radiation in atmosphere and vegetation. Adjusted models can be used to fast and precise analysis of biophysical parameters of the canopy. The canopy can be described as homogeneous layer consisting of leaves and spaces. The Radiative Transfer Models are algorithms which vary by input and output parameters, the level of the analysis, kinds of plants and other modifications. Models are used on two levels: single leaf and whole canopy. The first model, which is used in this research, is PROSPECT, which describes the multidirectional refl ectance and diffusion on a leaf level. It is often employed with other models that describe whole canopy. Leaf has the same properties on both sides, the reflection from the leaves is Lambertian. The input parameters in the model are: chlorophyll and carotenoid content, Equivalent Water Thickness and dry matter content and also leaf structure parameter that describe the leaf structure and complexity. Second model, which is used in the study, is the canopy reflectance model SAIL (Scattering by Arbitrarily Inclined Leaves). It simulates the top of the canopy bidirectional reflectance and it describes the canopy structure in a fairly simple way. In this analysis the 4-SAIL model will be used. This version has few input parameters that describe plants and soil: spectrometric data – reflectance and transmittance from leaves (the output parameters form PROSPECT model), biophysical canopy parameters (Leaf Area Index, brown pigment content, mean leaf inclination angle), soil brightness parameter, reflectance geometry (solar zenith angle, observer zenith angle, relative azimuth angle), ratio of diffuse to total incident radiation and two hot spot size parameters. The SAIL model is often combined with the model on leaf level – the PROSAIL model. The PROSPECT and SAIL are very rarely used to meadows, this kind of ecosystem is normally rather heterogeneous and modelling is quite difficult. In this study two Radiative Transfer Models (PROSPECT-5 and 4SAIL) were used on single leaves and a whole canopy level. In order to acquire the input data to both, models model and reference spectrums the fi eld measurements were done. The input parameters were recalculated using fields measurements and put into the models: PROSPECT and PROSAIL. Only one leaf structure parameter was fitted for each polygon individually. The spectral reflectance obtained from the model was compared with field data. Based on the calculated Root Mean Square Error the simulation was verified. The RMSE values were calculated for whole range from 400 to 2500 nm and for specific ranges. The correctness of simulated spectra were analysed dependent on the type of meadows (cultivated meadows with reduced amount of biomass, cultivated meadows with high amount of biomass and not cultivated meadows) and the value of three different biophysical parameters (Leaf Area Index, fresh biomass content and water content). Better results were obtained using PROSPECT model than PROSAIL. In the visible light more accurate values were calculated using PROSAIL and in the infrared using PROSPECT. Generally bigger errors were noticed in the infrared, especially middle infrared range. The effectiveness of the reflectance simulation was not influenced by different kind of meadows. Apart from that, better results were obtained on meadows with higher biomass value, bigger Leaf Area Index and lower water content. Generally, the PROSPECT and PROSAIL radiative transfer models can be used to simulate the spectral reflectance of vegetation on heterogeneous meadows. The models can be used to estimate the biophysical parameters, but it is necessary to correct the values of input variables (especially water content). Meadows are very complex environment and some of the parameters should be adjusted.

4

Wpływ orki na dwukierunkową charakterystykę odbicia spektralnego od powierzchni gleb w zakresie optycznym

Faryś M.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2000

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Vol. 10

34-1--34-12

PL

Prezentowana praca ma na celu określenie wpływu orki na dwukierunkową charakterystykę odbicia spektralnego od powierzchni gleb w zakresie optycznym. Kierunkowość geometrii powierzchni gleb wymaga zbadania wpływu orientacji poziomej kierunku zabiegu na wartość odbicia od analizowanych powierzchni. Wyjaśnienia zjawiska dokonano za pomocą analizy pomiarów spektralnych od powierzchni trzech typów gleb różniących się barwą, składem granulometrycznym, sekwencją uziarnienia, zawartością materii organicznej. W wyniku badań stwierdzono, że wraz ze zmianą orientacji kierunku zabiegów względem promieni słonecznych, następują zmiany w rozkładzie znormalizowanego odbicia w funkcji kąta zenitalnego obserwacji.