Simultaneous Visual Cryptography

A visual cryptography scheme (VCS), as proposed by M. Naor and A. Shamir, encodes a secret image into n different shares. The scheme ensures that only certain designated combinations of shares can recover the original image, while other combinations yield, in probabilistic sense, no information about the secret image. In this thesis, we show that there exist simultaneous visual cryptography schemes (SVCS), i.e. cryptographic schemes that allow for multiple secret images to be encoded across a set of n shares. The essential part of this research is to derive a set of formal definitions used to construct a valid SVCS and to design and examine different approaches for establishing valid SVCS constructions. In particular, we describe an SVCS that allows encoding n 1 distinct secret images across a set of n shares, and include a program that demonstrates the successful use of this SVCS in the appendix

A Lumped Specific Heat Capacity Approach for Predicting the Non-stationary Thermal Profile of Coffee During Roasting

Coffee undergoes numerous and relevant chemical and physical changes during roasting. These modifications lead to the development of those typical organoleptic properties of coffee, on which the acceptability of the product depends. The roasting process therefore, plays a central role within the coffee’s technological cycle. This crucial character of roasting has contributed to encouraging the continuous progress of the roasting industry incorporating the necessary scientific and technological research. However, due to the geometrical complexity and transformations undergone by coffee during roasting, the relationship between the heating mode and the material properties of coffee on the one hand and the non-stationary temperature profile within the bean on the other, are still far from being fully understood. In this presented work, a dynamic model is proposed for predicting the non-stationary thermal profile of coffee during roasting. The model is based on the assumption that the thermal effects occurring within the bean during roasting, such as moisture evaporation, can be approximately encompassed within a lumped together specific heat parameter. Using this hypothesis, it is possible to develop a mathematical model, which is quite simple in structure but still able to describe the two most important technological aspects, i.e. the evolution over time of the beans’ average temperature and internal thermal gradient

Desorption of artemisinin extracts of CIM-Arogya by supercritical carbon dioxide

Artemisinin is a drug for chloroquine resistant malaria and cerebral malaria treatments. In the recent past, there was an acute shortage of this drug and hence World Health Organization made a strategy to fulfil the Artemisinin demand. In this study, artemisinin was extracted by supercritical Carbon Dioxide (SFCO2) from CIM-Arogya, a variety of Artemisia annua, in temperature and pressure ranges of 313.1-333.1 K and 15\u201325 MPa. Artemisinin global yield isotherms were determined obtaining a maximum yield of 3.65 wt%. Artemisinin extracts were also obtained by hexane Soxhlet extraction: then, the crude extracts were purified using SFCO2, after adsorption on silica gel. Different desorption runs were performed with a 6 ml/min CO2 flow rate, in temperature and pressure ranges of 313.1\u2013333.1 K and 15\u201325 MPa. At different time intervals, extracts were collected and analysed: their yields varied from 2.75% to 4.34% function of the experimental conditions. Desorption trials were also correlated with different models

Gas Chromatographic Investigation of Solvents with Partial Miscibility

The solubility parameter theory has been used for the correlation of infinite dilution activity coefficients of hydrocarbons in mixed solvents (diethylene glycol and diethylphthalate) having partial miscibility in the liquid phase. The calculated values were in good agreement with those determined experimentally by GLC

Supercritical Antisolvent Precipitation of Quercetin Systems: Preliminary Experiments

Flavonoids have attracted a lot of attention due to their antioxidant, antitumor and antibacterial activities. Quercetin (3,5,7,3,4-pentahydroxyflavone) is a polyphenolic flavonoid that shows several biological effects including a strong inhibitory effect on the growth of several human and animal cancer cell lines and enhances the antiproliferative effect of cisplatin both in-vitro and in-vivo. In spite of a variety of its biological effects. Quercetin is very poorly soluble in water, which has limited its absorption upon oral administration. As known, the solubility of drug is often due to the increase of the surface/volume ratio which implies the increase of the number of surface atoms (or molecules) with respect to the number of bulk atoms (or molecules). With this aim, we investigated the use of supercritical antisolvent (SAS) technique for Quercetin microparticles generation finding the best operative conditions through the Peng Robinson’s Equation of State. The obtained simulation behaviors were confirmed by experimental precipitation: the physicochemical characterizations of the samples were also performe

Supercritical Antisolvent Precipitation of Quercetin Systems: Preliminary Experiments

Flavonoids have attracted a lot of attention due to their antioxidant, antitumor and antibacterial activities. Quercetin (3,5,7,3,4-pentahydroxyflavone) is a polyphenolic flavonoid that shows several biological effects including a strong inhibitory effect on the growth of several human and animal cancer cell lines and enhances the antiproliferative effect of cisplatin both in-vitro and in-vivo. In spite of a variety of its biological effects. Quercetin is very poorly soluble in water, which has limited its absorption upon oral administration. As known, the solubility of drug is often due to the increase of the surface/volume ratio which implies the increase of the number of surface atoms (or molecules) with respect to the number of bulk atoms (or molecules). With this aim, we investigated the use of supercritical antisolvent (SAS) technique for Quercetin microparticles generation finding the best operative conditions through the Peng Robinson’s Equation of State. The obtained simulation behaviors were confirmed by experimental precipitation: the physicochemical characterizations of the samples were also performe

Optimization of SC-CO2 Extraction OF Alpinia Galangal (L.) Wild and Estimation of Cost of Manufacturing (COM) Via SIMULATION Process

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Drug-polymer filled micro-containers for oral delivery loaded using supercritical CO₂ aided-impregnation

In this work we present an effective loading technique of micro-containers for oral drug delivery of a poorly water soluble drug in a solid dispersion with polymer. By combining inkjet printing and supercritical CO2 impregnation we load ketoprofen in a solid dispersion with poly(vinylpyrrolidone) (PVP) into cylindrical micro-containers providing unidirectional release. Both the printing and the impregnation step can be tuned in order to control drug loading with accuracy in the range of micro-grams

The Supercritical carbon dioxide extraction of \u3c9-3, \u3c9-6 lipids and \u3b2-sitosterol from Italian walnuts: A central composite design approach

A central composite design approach was used to optimize the supercritical carbon dioxide (SCCO2) extraction of Italian Walnut oil, considering the effect of pressure (from 82.3 to 317.6 bar), temperature (from 309.7 to 326.5 K) and process time (from 1.5 to 6.5 h) on extraction yield, fatty acid composition and sitosterol content. A multiple regression analysis indicated pressure and time as major parameters influencing the extraction yield. Those parameters also induced changes in the extract compositions giving the opportunity to obtain enriched fractions of polyunsaturated fatty acid (PUFA). Increased PUFA yields were obtained with higher pressure values but, for longer process times, extracts stated augmented amounts of saturated fatty acids. The different solubility behavior of PUFA and other lipids in SCCO2 could be exploited for the production of walnut oil fractions with high PUFA contents that can be considered as starting materials for the development of food supplements or functional foods