Development of Grid e-Infrastructure in South-Eastern Europe

Over the period of six years and three phases, the SEE-GRID programme has established a strong regional human network in the area of distributed scientific computing and has set up a powerful regional Grid infrastructure. It attracted a number of user communities and applications from diverse fields from countries throughout the South-Eastern Europe. From the infrastructure point view, the first project phase has established a pilot Grid infrastructure with more than 20 resource centers in 11 countries. During the subsequent two phases of the project, the infrastructure has grown to currently 55 resource centers with more than 6,600 CPUs and 750 TBs of disk storage, distributed in 16 participating countries. Inclusion of new resource centers to the existing infrastructure, as well as a support to new user communities, has demanded setup of regionally distributed core services, development of new monitoring and operational tools, and close collaboration of all partner institution in managing such a complex infrastructure. In this paper we give an overview of the development and current status of SEE-GRID regional infrastructure and describe its transition to the NGI-based Grid model in EGI, with the strong SEE regional collaboration.     

Preparation and properties of alumina-baria nano-composites

Barium doped alumina was prepared by calcination of gels obtained from metal chloride solutions by homogeneous precipitation with urea. The gels were either air-dried, oven-dried, microwave-dried or autoclave treated. The materials were analysed by SAXS, XRD, DTA/TG and TEM. The phase composition of the calcined products depended on the gel drying procedure. Barium aluminates formed directly at low temperatures in the microwave treated gel because of the uniform distribution of barium in the dried gel. After calcination at 1200 °C the aluminates were uniformly distributed as nanoscale particles within an -Al₂O₃ matrix. In contrast, autoclave treated samples initially consisted of boehmite crystals coated with barium carbonate which reacted on calcination to form a surface layer of BaAl₂O₄. The autoclaved material withstood 1 h at 1400 °C in air without transformation to -Al₂O₃. This increased thermal stability of transition alumina (-Al₂O₃) is attributed to the presence of the BaAl₂O₄ surface layer. The final transformation to -Al₂O₃ was associated with the transformation of a surface layer of BaAl₂O₄ to nanoscale particles of BaAl_9.2O_14.8.     

Tooth diseases in the medieval population of Gracanica near Valjevo

The analyses of the pattern of dental disease in the Late Medieval Serbian population from cemetery excavations in the archaeological site Grachanica were based on the study of tooth wear, ante-mortem tooth loss, caries, hypoplasia, alveolar resorption, abscesses and calculus. The total sample of all available skeletons with almost complete permanent dentition numbers 45 individuals. Dental sample comprises 178 maxillary teeth and 337 mandibular teeth. The presence of dental caries was scored taking into consideration the size of the lesion (four degrees) and its position on the tooth. The degree of tooth wear was graded into one of four categories: atrition of enamel only; atrition involving dentin; atrition up to the level of fissure at the occlusal surface of the molar teeth, and exposure of the pulp chamber. The cystic defects within the alveolar bone were recorded according to their aetiology, size and position. Radiographic study had not been done in order to detect periapical destruction, so the presence of such destruction was recognizable in advanced stages associated with the appearance of fistula penetrating the compact alveolar bone usually at the buccal side. The condition of the alveolar crest resorption, as the evidence of periodontal disease, was graded into three categories, and the distance from the cemento-enamel junction to the alveolar crest was measured. The analysis of dental pathology profile consisted of the two reporting methods: individual count method (prevalence of disease based on the number of individuals affected) and tooth count method (distribution of lesions frequency on tooth type and class). The Grachanica dentition exhibits a dental pathology profile typical of agricultural medieval populations in this region. Tooth wear was the most frequent, affecting 95% of individuals. Dental caries and ante-mortem teeth loss exhibit also high frequency (51% and 69%). Dental pains of low prevalence include abscesses (13%) and enamel hypoplasia (20%). In the material examined, the carious process was responsible for pulp exposure to infection in all cases of abscess formation. The results obtained suggest that food processing technology and nature of diet allowed use of abrasive in the food and that oral hygiene was at the low level. On the other hand, there were not a lot of people who were subjected to stress-induced growth disruptures. The findings reported here contribute to understand how dietary change and life conditions are related to the changing patterns of dental diseases in medieval populations.     

Increased fat intake in dietetic treatment of viral hepatitis and levels of some serum lipids

This study examines length of residence for movers--that subsection of the population which accounts for the high mobility rates in the United States. The propensity for repeated migration is studied in relation to economic opportunities and previous familial and personal contacts. The results indicate no influence of economic opportunities on duration of residence. This finding is consistent with recent research that indicates economic conditions are not a general stimulus for out-migration, although they are for inmigration. On the other hand, length of residence is found to be longer where previous familial and personal contacts existed. Overall, the results provide additional evidence of the importance of social, as opposed to strictly economic variables in the migration process.     

Influence of carriers on the capacitance of p-n junctions with deep donors

Applying the definition of p-n junction capacitance [1], which takes into account the effect of carriers in the space-charge region, a sufficiently accurate approximate expression is derived for the low-frequency capacitance of an abrupt p-n junction containing both deep and shallow donor impurities within the n-region. The capacitance expression can be written in conventional Schottky form, putting the intercept voltage if V_in instead of the diffusion potential. It is shown that V_in differs considerably from the generally known V_i0 expression obtained on the basis of the depletion layer approximation. This difference increases with the degree of p-n junction asymmetry, or the decrease of deep donor impurity ionisation energy, and is dependent also on the concentration ratio of deep and shallow donors. The most important difference between V_in and V_i0 lies in the fact that V_i0 in contrast to V_in, is independent of the applied voltage, and is therefore applicable only with very high reverse voltages, where equivalence between V_in and V_i0 is valid.     

A comparative study of Mesua ferrea L. based hybrid fuel with diesel fuel and biodiesel

The study presents preparation of a Mesua ferrea L. seed-oil-based emulsion hybrid fuel system by blending with alcohols (ethanol and butan-2-ol) in which butan-2-ol was employed as a surfactant. The study also deals with the investigation of the effect on fuel properties of the hybrid fuel due to the variation in surfactant amount and analysis of the prepared hybrid fuel system by ¹H nuclear magnetic resonance (¹H NMR). The experimental results show that the properties of the hybrid fuels were comparable to that of diesel and biodiesel.     

Effect of ceramic-based coatings deposited on low-alloyed steel T/P22 10H2M exposed at high temperature

The study was carried out in order to evaluate oxidation resistance of the ceramic coatings based on SiO₂-B₂O₃-TiO₂-Na₂O composition deposited on the low-alloyed steel T/P22 (10H2M) surface exposed for 1000 h at 540°C in oxidation atmosphere. Kinetic data were recorded periodically every 250 h; macro- and microanalyses as well as chemical composition were carried out using macrolenses, SEM, EDS, EDS X-ray mappings. The results indicated a high degree of protection by ceramic coatings; much lower mass gain was observed for the coated materials than for the uncoated T/P22 (10H2M) steel. No detachment, delamination, chipping of a coating were found from the steel surface; some of the coatings showed perpendicular tiny cracks to the bulk metal surface.     

Structural and thermophysical properties characterization of continuously reinforced cast Al matrix composite

In this work the process of manufacturing a continuously reinforced cast Al matrix composite and its properties are presented.The described technology permits obtaining a structural material of competitive properties compared to either heat treatable aluminum alloys or polymer composites for several types of applications.The examined thermophysical properties and structural characterization,including material anisotropy,coupled with the results of previous measurements of the mechanical properties of both Al2O3reinforcing filaments and metallic prepregs have proven the high quality of this material and the possibility of its operation under special loading modes and environmental conditions.Microscopic examinations(LM,SEM)were carried out to reveal the range of morphological homogeneity of the microstructure,the anisotropy of the filament band distribution,and simultaneously the adhesive behavior of the metal/fiber interface.The 3D morphology of the chosen microstructure components was revealed by computed tomography.The obtained results indicate that special properties of the examined prepreg materials have been strongly influenced,on the one hand,by the geometry of its internal microstructure,i.e.spatial distribution and volume fraction of the Al2O3 reinforcing filaments and,on the other hand,by a very good compatibility obtained between the individual metal prepreg components.     

Development of whey-based beverages

This paper considers beverages consisting of whey, fruit components (orange, pear, peach, and apple), citric acid and sucrose. It also offers their optimal composition. The dry matter of the fruit component, the pH of the beverage and its sucrose content were independent variables. Blends were prepared in accordance with the factorial design. After pasteurization, they were exposed to a sensor analysis so that the following characteristics were estimated: flavour, odour, colour, sediment, appearance and total quality (sum of the previous factors). By applying the regression analysis method, a mathematical model of each characteristic was derived. None of the characteristic functions had an extreme, so the maxima lay at the boundaries of the independent variables (6% of dry matter and 4% or 2% of sucrose ). Only the pH changed within a narrow range. The statistical method has shown that the quality of blends with orange and pear mostly depends on the sucrose content, while the quality of blends with peach and apple depends on the dry matter of the fruit. Interaction of dry matter and sucrose is most significant for the blend with pear, while the balance between sucrose and pH strongly depends on the quality of all the other products. The peach–whey beverage containing 6% of dry matter and 2% of sucrose as well as having pH 3.6 proved to be the best.