Laser induced diffuse reflectance imaging – Monte Carlo simulation of backscattering measured on the surface

The Monte Carlo simulation algorithm of photon trajectory computation is implemented in object oriented R code. Diffuse reflectance, also called backscattering, is modeled in semi-infinite homogeneous media. Spatial photon flux leaving the surface of the media is collected. The profile of intensity along radii relative to the incident point is used to simulate measurement of computer vision systems. Four optical parameters of the media are used: absorption coefficient, scattering coefficient, anisotropy factor and refractive index. Five parameters are used to describe configuration of the vision system: number of photons, radius of circular light beam, limiting energy level of photons, radius of observed area, spatial resolution of the vision system. • The incident angle of the light beam is included in the photon launch procedure. Initial direction is typically assumed to be normal with x,y,z coordinates of 0,0,1. In the proposed modification, initial move vector is calculated based on the incident angle and refractive index of the media. Additionally, elliptic distortion of the circular light beam on the surface is calculated based on the incident angle. • Photon flux leaving media through the surface is corrected with Lambertian method to measure intensity captured by an imaging device in normal position. • The software implementing the method is written in R language, the R code is available as standard package

Analysis of Hue Spectra During Storage of Pepper (Capsicum annuum)

Color information is widely used in non-destructive quality assessment of perishable horticultural produces. The presented work investigated color changes of pepper (Capsicum annuum L.) samples received from retail system. The effect of storage temperature (10±2°C and 24±4°C) on surface color and firmness was analyzed. Hue spectra was calculated using sum of saturations. A ColorLite sph850 (400-700nm) spectrophotometer was used as reference instrument. Dynamic firmness was measured on three locations of the surface: tip cap, middle and shoulder. Significant effects of storage conditions and surface location on both color and firmness were observed. Hue spectra responded sensitively to color development of pepper. Prediction model (PLS) was used to estimate dynamic firmess based on hue spectra. Accuracy was very different depending on the location. Firmness of the tip cap was predicted with the highest accuracy (RMSEP=0.0335). On the other hand, middle region cannot be used for such purpose. Due to the simplicity and rapid processing, analysis of hue spectra is a promising tool for evaluation of color in postharvest and food industry

Vizsgálatok a vízmolekula állapotjelző-független klasszikus modelljének fejlesztéséhez = Studies for the development of state-independent classical model of the water molecule

Megmutattuk, hogy minden eddigi modell hiányossága, hogy nem képes pontosan becsülni a nagy nyomású jég polimorfok belső energiáját. Az Ih jéghez viszonyítva pl. a hasonló hőmérsékletű jég VII energiája a kísérleti eredmények alapján csak kb. 4-6 kJ/móllal magasabb, szemben a modellszámítások által szolgáltatott 8-10KJ/mól különbséggel. Megmutattuk, hogy a folyadék-gőz egyensúly, a második viriálegyüttható, a gőznyomás, az olvadási hőmérséklet értékeinek becslését, a merev modellek nem képesek kielégítően megtenni. A jég kristályos módosulatai közül 9-ben a protonok pozíciója rendezetlen. A különféle konfigurációk kézenfekvő vizsgálata a kötésben lévő molekula dimerek orientációjának a statisztikája. Megállapítottuk, hogy a dimer elrendeződések a hibahatároknál nagyobb energiakülönbségeket eredményezhetnek, ami a jég fázisok relatív stabilitásánál nem elhanyagolható. Kifejlesztettünk egy új polarizálható modellt, amely számos tulajdonságot jól becsül. A nóvum a modellünkben az, hogy a polarizáció befolyásolja a molekula méretét. Ezzel a pályázat alapvető célját elértük. Kifejlesztettünk egy olyan új, egzakt izobár MD algoritmust, amely a nyomás kontrollt a sokkal egyszerűbb sztochasztikus módszert alkalmazásával éri el. A pályázat támogatásával születtek még munkák az inverz probléma megoldásával, illetve alkalmazásával kapcsolatosan. Túlnyomóan Tóth Gergely, illetve kisebb részben Pusztai László vezetésével. | We pointed out a shortage of every model developed so far that they are unable to predict the internal energy of the high pressure ices correctly. Relative to the Ih phase the internal energy of ice VII should be only 4-6kJ/mol higher according to experiments, instead of the 8-10 kJ/mol difference predicted by the models. We showed that in the cases of liquid-vapor equilibrium, second virial coefficient, and vapor pressure, and the melting temperature of the ice the models cannot give results close to the experimental ones. There are 9 polymorphs of ice showing hydrogen bond disorder. We studied this phenomenon with emphasis on the ice III - IX disordered- ordered pair. The distribution of H-bond connected molecule pairs is an important factor determining phase stability because the energy differences resulted by different distributions can be 1-0.01kJ/mol. We developed a novel interaction model for the water molecule. In addition to being polarizable, the size of the molecule increases with its dipole moment. The estimated properties agreed well with experimental results. This way we achieved the ultimate goal of this project. We developed a new, exact algorithm for isobar molecular dynamics simulation by stochastic pressure constraint. In addition to the results above, several works were carried out related to the inverse problem of liquids using the support of this project. These studies were carried out by G. Tóth and L. Pusztai

Stability of Ampelometric Characteristics of Vitis vinifera L. cv. 'Syrah' and 'Sauvignon blanc' Leaves: Impact of Within-vineyard Variability and Pruning Method/Bud Load

Historically, grapevine (Vitis vinifera L.) leaf characterisation has been a driving force in the identification of cultivars. In this study, ampelometric (foliometric) analysis was done on leaf samples collected from hand-pruned, mechanically pruned and minimally pruned ‘Sauvignon blanc’ and ‘Syrah’ vines to estimate the impact of within-vineyard variability and a change in bud load on the stability of leaf properties. The results showed that within-vineyard variability of ampelometric characteristics was high within a cultivar, irrespective of bud load. In terms of the O.I.V. coding system, zero to four class differences were observed between minimum and maximum values of each characteristic. The value of variability of each characteristic was different between the three levels of bud load and the two cultivars. With respect to bud load, the number of shoots per vine had a significant effect on the characteristics of the leaf laminae. Single leaf area and lengths of veins changed significantly for both cultivars, irrespective of treatment, while angle between veins proved to be a stable characteristic. A large number of biometric data can be recorded on a single leaf; the data measured on several leaves, however, are not necessarily unique for a specific cultivar. The leaf characteristics analysed in this study can be divided into two groups according to the response to a change in bud load, i.e. stable (angles between the veins, depths of sinuses) and variable (length of the veins, length of the petiole, single leaf area). The variable characteristics are not recommended to be used in cultivar identification, unless the pruning method/bud load is known

Influence of parameters of drying on laser induced diffuse reflectance of banana discs

Banana discs of 1 cm thickness were immersed into different antioxidant solutions to slow down potentially disturbing discoloration during drying. Samples were randomly split into 8 groups according to the 2^p experimental design. Two antioxidant solutions with 1.66% and 4.59% ascorbic acid, two levels of drying temperature with 50°C and 80°C, two levels of drying time with 6h and 8h were used or adjusted. Laser diodes of seven wavelengths (532, 635, 650, 780, 808, 850 and 1064 nm) were selected to illuminate the surface and light penetration pattern was evaluated on the basis of radial profiles. Profiles acquired at three wavelengths (532, 635 and 650 nm) were found to respond sensitively to adjusted parameters. As a result of drying, intensity decay was observed to move closer to incident point. Significant effect (p<0.01) of temperature, drying time and their interaction was found on extracted descriptive attributes of intensity profiles: full width at half maximum (FWHM), distance of inflection point (DIP) and slope of logarithmic decay (SLD). Beyond their presence, antioxidant concentration was neutral factor without significant contribution to the model. Results were in agreement with reference spectroscopic measurements, especially with NDVI index. Promising results suggest that evaluated method might be suitable for monitoring purposes during drying of fruits