Authors:Mykola Sysyn, Vitalii Kovalchuk, Ulf Gerber, Olga Nabochenko and Andriy Pentsak
Railway ballast tamping is one of the cost-expensive renewal and maintenance works of railway superstructure. The quality of ballast consolidation influences its resistance to residual deformations and long-term deterioration of track geometry. The process of ballast compaction along the sleeper under the vibration loading is complex and depends on many factors. The ballast flow processes under the vibration loading can produce both consolidation and un-consolidation of ballast material. The present study is devoted to the experimental investigation of ballast consolidation inhomogeneity. The method of ballast local consolidation measurement is proposed. The method is based on the velocity of impact wave propagation that is measured with device. The application of modern microcontroller and sensor techniques provided simple and reliable multi-point velocity measurements in a ballast layer. That enables well enough spatial resolution of ballast consolidation inhomogeneity. The measurement analysis has shown more than 4 times higher consolidation under the sleeper center than for unconsolidated ballast.
Chladný E., Štujberová M. The equivalent unique global and local imperfection in the shape of the elastic critical buckling mode for the verification the buckling resistance of compressed members and frame structures using second order analysis, Two
Earlier studies on protein antinutrients and allergens naturally present in legume seeds have shown that these compounds are responsible for the impaired performance of experimental animals when exposed for a long term. These reactions were characterized by lowered nutritional performance, reduced growth, pure digestion and absorption, changes in gut motility, structural damage in small intestine and diarrhoea. A lot of efforts were made for gathering data on heat stability and resistance to chemical or enzyme treatments of these compounds to reduce or eliminate these harmful effects.A novel research approach has described that these compounds have a special regulatory role in the gut metabolism and modulate hormone and immune responses which resulted in a novel concept of “nonnutritive biologically active compound”. These studies revealed that the chemical structure of these compounds was responsible for the induction of such physiological reactions as increased endogen N-loss, change in the plasma amino acid concentration or plasma lipid composition with reduction of total cholesterol level or developing of harmful immune responses to luminal antigens resistant to the gut digestion. Resent studies were therefore related to the description of their interaction with the gut metabolism and understanding of the modulation of gut immune responses to luminal antigens.This review was inspired to summarise the research efforts on the above field performed by the Nutritional and Biological Units of the Central Food Research Institute.
Authors:N. Elmnasser, M. Ritz, F. Leroi, N. Orange, A. Bakhrouf and M. Federighi
Pulsed light is a new method intended for the decontamination of food surfaces using short, high frequency pulses of an intense broad spectrum. The effects of broad spectrum pulsed light on the survival of
SF680 populations on agar and in a liquid medium were investigated during this study. The sterilisation system generated 1.5 J cm
per pulse with eight lamps for 300 μs. In the case of surface-seeded cells, a 7.8, 8.14 and >7.14 log reduction was obtained for
L. monocytogenes, Ps. fluorescens
, respectively, after a single pulse of treatment. Inactivation levels were lower for depth-plated cells: indeed, 10 pulses of treatment achieved 1.6, 2.03 and 4.78 log reductions for
MF37, respectively. After 5 pulses,
exhibited a 4.6 log reduction. Similarly, bacterial cells in suspension treated with 3 pulses were reduced by 0.52, 0.8, 2.07 and 2.05 for
, respectively. No resistance to pulsed light was observed during our experiments.
Authors:Z. Šereš, J. Gyura, M. Eszterle and Gy. Vatai
The produced sugar, as the final product in sugar production technology, has to contain as low non-sucrose compounds with coloured matters as possible. Ultrafiltration and nanofiltration could be one of the solutions for a more effective separation of non-sucrose compounds from intermediate products from which sucrose directly crystallises. The separation of non-sucrose compounds by ultra- and nanofiltration is investigated on syrup solution with 40% d.m. content, which is an intermediate product in the phase of sucrose crystallisation. Further, this paper investigates variables in the ultrafiltration and nanofiltration of syrup solutions, such as variations in pore sizes of the polymer membranes, syrup temperatures, syrup flow rates and transmembrane pressures. During ultrafiltration, under the investigated conditions; permeate flux is about 10 times less than water flux (150 m-2h-1) on the first membrane and 8 times less than water flux (285 m-2h-1) on the second membrane, while the nanofiltration permeate flux is 15 times less than water flux (320 m-2h-1). The permeate flux decreases due to the adsorption of non-sucrose compounds by the filter membranes and the resultant increase in resistance to mass transfer. The colour content is about 58% lower by ultrafiltration using membranes. There is no great difference in colour separation between the used ultrafiltration membranes with different pore sizes. Nanofiltration was shown to separate 76% of coloured matter from syrup. In all the examined cases, permeate turbidity could be reduced by 75-80%, according to feed.
Authors:Alexandre Léonard, Aurélien Vantomme, Claire Bouvy, Nicolas Moniotte, Pascal Mariaulle and Bao-Lian Su
A great deal of progress has recently been made in the field of ordered porous materials with uniform channel dimensions that can be adjusted over a wide range of length scales. The present paper describes the state of the art and the evolution from highly ordered mesoporous silica, aluminosilicate and pure carbon materials to our very recent success in hierarchically structured meso-macroporous carbon materials, single and binary oxides and aluminosilicates. By means of selected examples, we want to shed some light on the current strategies for the conception of these sophisticated materials. The great potential applications of these new nanomaterials emerge while their real utilisation in some expected and traditional industrial processes such as catalysis, separation, electrode materials for fuel cells and biomaterials still faces some important challenges, for example, the high price, the pelletisation and the stability (thermal, hydrothermal and water resistance). Some new perspectives, which can open the concrete applications of these materials in nanotechnology, biotechnology, information technology and medical purposes, will be prospected.
Authors:V. Koval, Y. Yasievich, M. Dusheyko, A. Ivashchuk, O. Bogdan and Y. Yakymenko
Silicon nanocomposites (nc-Si) with rare earth metals (REM) were synthesized by electron-beam evaporation. The structure of nanocomposites was studied by atomic-force microscopy. The size of nanocrystallites was about 10–40 nm. Also chemical composition of obtained material was examined. The distribution of rare earth elements (REE) was uniform in film thickness, but it was characterized by a presence of maximum peak at the interface film-substrate. In the work the electrical and optical properties of nanocomposites Si:REE were investigated. Silicon nanocomposites with Eu or Y were characterized by high sensitivity to visible radiation. The ratio of dark to light resistance was achieved to 2 orders of magnitude, making this material very promising to use in thin-film photosensors. After deposition of nanocomposites Si:REE on silicon substrate, the heterojunction was formed at the interface film-substrate, for which the sensitivity to visible radiation was observed too (1–2 mA/lmV). Also, the presence of photovoltaic effect in such structures was shown, so they can be the basis of cheap thin-film solar cells, using the relevant design solutions.
The determination of service life of concrete structural members is an important aspect of durability design. The scope of the paper is to present an effective and easy to use method for the estimation of service life of pre-cast concrete structural members. A stochastic approach using stochastic finite element method was applied during the analysis. The effect of creep, shrinkage, relaxation, carbonation induced corrosion and deterioration of cross-sectional sizes on the mean value and standard deviation of bending moment resistance, as well as the change of load effect in time were taken into account during the calculations. The results of probabilistic analysis were compared to results of bending tests that were carried out on pre-stressed concrete beams. The use of the introduced method for the purposes of service life estimation is also presented in case of a long-span, pre-cast, pre-stressed concrete beam. Initial stochastic parameters of material properties and structural geometry were derived from destructive material tests and geometry measurements on appropriate beams. Considering the same safety level and design-life as in Eurocode 2, the introduced probabilistic design method delivers about 10% higher load carrying capacity as the application of relevant Eurocode 2 standard in case of the presented beam.
Authors:Norin Filip-Vacarescu, Aurel Stratan and Dan Dubina
1998-1 2004 , Design provisions for earthquake resistance of structures: General rules — Seismic actions and general requirements for structures, CEN, EN1998-1-1.
P100-1/2006, Seismic design code, Part I (in Roman)