Variability of solar UV-B irradiance: in situ monitoring and model calculation of the vitamin D synthetic capacity of sunlight

The prediction of the biological effects of solar radiation on human health, in particular involving terrestrial level of solar ultraviolet (UV) radiation, requires the development of an adequate methodological strategy for remote sensing. To date, it is well understood that, in appropriate doses, UV radiation is beneficial for people, specifically due to the production of vitamin D₃ in the skin from its precursor 7-dehydrocholesterol. But as far as excessive UV exposure causes acute and chronic health effects, in most cases biological activity of solar UV radiation is calculated by weighting solar UV spectra with International Commission on Illumination (CIE) erythemal action spectrum. Yet the beneficial vitamin D synthetic capacity of sunlight cannot be correctly estimated in this way because of the significant difference between the erythemic and vitamin D synthesis action spectra. With due regard to the essential role of vitamin D₃ for human health, in this article we examine the possibility of simplified estimation in situ of provitamin D₃ photoconversion into previtamin D₃ from the UV absorption spectra of an in vitro model of vitamin D synthesis upon exposure to sunlight. A large-scale linear correlation (R = 0.99) was found on a clear summer day between the concentration of accumulated previtamin D₃ and maximum absorbance decline in the initial provitamin D₃ absorption spectrum. However, long-term observations showed a poorer (R = 0.77) correlation, and a source of ambiguity of such indirect estimation of previtamin D₃ concentration is discussed in detail. In addition, we propose a reliable algorithm for the direct calculation of previtamin D₃ accumulation using solar UV spectra as input data to the reaction model of previtamin D photosynthesis and demonstrate the critical dependence of previtamin D₃ accumulation on stratospheric ozone, season, latitude and cloudiness. The comparison of experimental and simulation data conforms to recent findings on Europe's darker atmosphere in the UV-B and implicates the practical certainty of the presented algorithm for the calculation of the vitamin D synthetic capacity from the remotely sensed solar spectra.     

Scandinavian Thins on Top of Cake: New and Improved Algorithms for Stacking and Packing

We show how to compute the smallest rectangle that can enclose any polygon, from a given set of polygons, in nearly linear time; we also present a PTAS for the problem, as well as a linear-time algorithm for the case when the polygons are rectangles themselves. We prove that finding a smallest convex polygon that encloses any of the given polygons is NP-hard, and give a PTAS for minimizing the perimeter of the convex enclosure. We also give efficient algorithms to find the smallest rectangle simultaneously enclosing a given pair of convex polygons.     

A possibilistic approach to risk aversion

In this paper a possibilistic model of risk aversion based on the lower and upper possibilistic expected values of a fuzzy number is studied. Three notions of possibilistic risk premium are defined for which calculation formulae in terms of Arrow–Pratt index and a possibilistic variance are established. A possibilistic version of Pratt theorem is proved.     

Comparative assessment of the impact of molecular scattering and total ozone content on the characteristics of UV radiation in the atmosphere

The ultraviolet (UV) radiation reaching the Earth's surface has an impact on living organisms, and the beneficial and harmful aspects have been the subject of much discussion. The Earth's atmosphere filters out solar radiation wavelengths less than 280 nm. The atmospheric ozone is the major medium attenuating the UV radiation and is characterized by an inhomogeneous distribution in the atmosphere with a maximum height level of 20–25 km. However, the flux of the UV radiation is also significantly reduced by molecular scattering, whose influence is specifically estimated in this study. In this context, the simplest model of a homogeneous atmosphere is used, considering the six wavelengths 280, 300, 320, 340, 360, 400 nm at two atmospheric pressure levels, 1000 and 500 mb (corresponding on average to altitudes of 0 and 5 km, respectively, above the mean sea level), and three atmospheric ozone levels, normal for summer mid-latitudes plus those decreased by 10% and 50%, respectively. The surface albedo is assumed to be 0 and 0.8 (corresponding to water and snow cover). For the calculations performed, the UV irradiances, the proportion of the scattered light on the surface level and the ratio of the reflected to the transferred irradiance in the atmosphere were considered. In addition, the radiative characteristics of the clear atmosphere were calculated using the Eddington method.     

A visual digital library approach for time-oriented scientific primary data

Digital Library support for textual and certain types of non-textual documents has significantly advanced over the last years. While Digital Library support implies many aspects along the whole library workflow model, interactive and visual retrieval allowing effective query formulation and result presentation are important functions. Recently, new kinds of non-textual documents which merit Digital Library support, but yet cannot be fully accommodated by existing Digital Library technology, have come into focus. Scientific data, as produced for example, by scientific experimentation, simulation or observation, is such a document type. In this article we report on a concept and first implementation of Digital Library functionality for supporting visual retrieval and exploration in a specific important class of scientific primary data, namely, time-oriented research data. The approach is developed in an interdisciplinary effort by experts from the library, natural sciences, and visual analytics communities. In addition to presenting the concept and to discussing relevant challenges, we present results from a first implementation of our approach as applied on a real-world scientific primary data set. We also report from initial user feedback obtained during discussions with domain experts from the earth observation sciences, indicating the usefulness of our approach.     

Protective Coatings on Heat-Resistant Nickel Alloys (Review)

The literature on materials for protective coatings on heat-resistant nickel alloys and methods for their production is reviewed in order to generalize the results and determine the principal directions for solution of the problem under consideration. It is shown that a promising approach is the development of layered composite ceramic coatings which, thanks to a graded variation of properties, are able to provide an optimal combination of adherence, mechanical strength, and corrosion and heat resistance. The methods of physical vapor deposition, plasma spraying, and electron-beam deposition remain the principal industrial processes for coating deposition.     

Fluorographene: a two-dimensional counterpart of Teflon

A stoichiometric derivative of graphene with a fluorine atom attached to each carbon is reported. Raman, optical, structural, micromechanical, and transport studies show that the material is qualitatively different from the known graphene-based nonstoichiometric derivatives. Fluorographene is a high-quality insulator (resistivity >10(12) Ω) with an optical gap of 3 eV. It inherits the mechanical strength of graphene, exhibiting a Young's modulus of 100 N m(-1) and sustaining strains of 15%. Fluorographene is inert and stable up to 400 °C even in air, similar to Teflon.     

High Security for De-Duplicated Big Data Using Optimal SIMON Cipher

Cloud computing offers internet location-based affordable, scalable, and independent services. Cloud computing is a promising and a cost-effective approach that supports big data analytics and advanced applications in the event of forced business continuity events, for instance, pandemic situations. To handle massive information, clusters of servers are required to assist the equipment which enables streamlining the widespread quantity of data, with elevated velocity and modified configurations. Data deduplication model enables cloud users to efficiently manage their cloud storage space by getting rid of redundant data stored in the server. Data deduplication also saves network bandwidth. In this paper, a new cloud-based big data security technique utilizing dual encryption is proposed. The clustering model is utilized to analyze the Deduplication process hash function. Multi kernel Fuzzy C means (MKFCM) was used which helps cluster the data stored in cloud, on the basis of confidence data encryption procedure. The confidence finest data is implemented in homomorphic encryption data wherein the Optimal SIMON Cipher (OSC) technique is used. This security process involving dual encryption with the optimization model develops the productivity mechanism. In this paper, the excellence of the technique was confirmed by comparing the proposed technique with other encryption and clustering techniques. The results proved that the proposed technique achieved maximum accuracy and minimum encryption time.     

Integrating resource criticality assessment into evaluation of cleaner production possibilities for increasing resource efficiency

A stable and secure source of raw materials is the key to any successful industrial activity. Resource criticality is often discussed in the context of the impact on the economies of certain geographic regions. However, the availability of required resources first of all concerns the competitiveness of industrial companies, especially in those countries which do not possess abundant natural resources. The Lithuanian economy relies heavily on imports since the country does not have abundant natural resources. The paper introduces resource criticality as an additional dimension for evaluating and prioritizing resource efficiency improvement options. Evaluation of resource criticality was integrated into the methodology for evaluation of Cleaner Production. Simple additive weighting (SAW) was used to solve the multi-criteria decision-making problem. The previous study on the natural resources that are imported to Lithuania revealed that metals are among the most important raw materials in terms of economic importance, supply, and environmental risks. Therefore, a typical metal processing company in Lithuania was selected for the detailed investigation of technological processes and Cleaner Production possibilities. The selected company processes about 3000 tons of various metals per year. The results of Process Material Flow Analysis show that most of the metal waste is generated during the metal plate cutting process (about 30.3 % of total metal consumption). Three resource efficiency improvement alternatives were evaluated and compared. The suggested decision support system was tested in order to decide on a definitive solution. The results reveal that evaluation of resource criticality in terms of geostrategic supply risk and economic importance can be used as an advantageous criterion to support the prioritization of Cleaner Production alternatives.