1,536 research outputs found
Transformacija raspodjele čeličnih proizvoda u Poljskoj i Slovačkoj
Steel industry is one of the most globalized branch, globalization has had the influence on iron ore supply, steel production and distribution as well. In last years, steel products distribution process has changed significantly, because of rising competitiveness due to common world market influence and main global players actions. The paper presents changes in steel products distribution in Poland and Slovakia focusing on main steel producers activity in distribution as well as distributors response on new market situation.Čelična industrija je jedna od najviše globaliziranih grana s utjecajem na opskrbu čeličnih proizvoda i njihovoj raspodjeli. U posljednjim godinama raspodjela čeličnih proizvoda značajno se promijenila glede utjecaja konkurencije u zajedničkom svjetskom tržištu i presudnim globalnim akcijama. Članak daje izmjene u raspodjeli čeličnih proizvoda u Poljskoj i Slovačkoj s naglaskom na najvažnije akcije proizvođača čelika i odgovarajuće raspodjele pri novoj tržišnoj situaciji
Transformation on steel products distribution in Poland and Slovakia
Steel industry is one of the most globalized branch, globalization has had the influence on iron ore supply, steel production and distribution as well. In last years, steel products distribution process has changed significantly, because of rising competitiveness due to common world market influence and main global players actions. The paper presents changes in steel products distribution in Poland and Slovakia focusing on main steel producers activity in distribution as well as distributors response on new market situation
Features of atomic and molecular beams passage through capillary systems in the presence of evanescent light waves
A model of the transverse cooling of atoms in the field of a surface light wave inside a glass capillary is considered. The attenuation coefficient for transverse oscillations of atom in a microcapillary is estimated, and the length of effective atom cooling is calculated. A 3D model is constructed. The possibility for the practical application of this phenomenon both to develop the technology of atomic lithography and to fabricate the nanostructures is considered
A flexible, extensible object oriented real-time near photorealistic visualization system:the system framework design
In this paper we describe a novel, extensible visualization system currently under development at Aston University. We introduce modern programming methods, such as the use of data driven programming, design patterns, and the careful definition of interfaces to allow easy extension using plug-ins, to 3D landscape visualization software. We combine this with modern developments in computer graphics, such as vertex and fragment shaders, to create an extremely flexible, extensible real-time near photorealistic visualization system. In this paper we show the design of the system and the main sub-components. We stress the role of modern programming practices and illustrate the benefits these bring to 3D visualization. © 2006 Springer-Verlag Berlin Heidelberg
Chaos induced coherence in two independent food chains
Coherence evolution of two food web models can be obtained under the stirring
effect of chaotic advection. Each food web model sustains a three--level
trophic system composed of interacting predators, consumers and vegetation.
These populations compete for a common limiting resource in open flows with
chaotic advection dynamics. Here we show that two species (the top--predators)
of different colonies chaotically advected by a jet--like flow can synchronize
their evolution even without migration interaction. The evolution is
charaterized as a phase synchronization. The phase differences (determined
through the Hilbert transform) of the variables representing those species show
a coherent evolution.Comment: 5 pages, 5 eps figures. Accepted for publication in Phys. Rev.
The role of nω-nitro-L-arginine in modulation of pulmonary vascular tone in the maturing newborn pig
AbstractCurrent therapeutic modalities for treatment of newborn pulmonary hypertensive crisis include but are not limited to the administration of nitric oxide (endothelium-derived relaxing factor). However, few data are available on the role of endogenously produced endothelium-derived relaxing factor in the modulation of pulmonary vascular tone in the neonate. In the current study, we investigated the acute effects of Nω-nitro- L -arginine (a potent competitive inhibitor of endothelium-derived relaxing factor synthase) on the pulmonary vasculature of anesthetized open-chest 48-hour-old ( n = 8) and 2-week-old ( n = 7) Yorkshire pigs. After baseline data were acquired, all animals received a 10 mg/kg per minute infusion of Nω-nitro- L -arginine for 10 minutes. To discern distal and proximal pulmonary arterial vessel changes, input mean and characteristic impedance were respectively determined. Pulmonary vascular resistance was also calculated (units determined in dyne • sec • cm -5 plus or minus the standard errorof the mean). Results showed Nω-nitro- L -arginine infusion did not significantly alter baseline pulmonary arterial pressure (22,370 ±1473 dyne/cm2 ), pulmonary vascular resistance (5171 ±805 dyne • sec • cm -5 ), input impedance (6343 ±806 dyne • sec • cm -5 ), or characteristic impedance (2073 ±418 dyne • sec • cm -5 ) in 48-hour-old pigs. In 2-week-old pigs, infusion of Nω-nitro- L -arginine elevated pulmonary arterial pressure (18,162 ±1415 dyne/cm 2 versus 23,838 ±1810 dyne/cm 2 , p = 0.015), pulmonary vascular resistance (810 ±137 dyne • sec • cm -5 versus 1519 dyne • sec • cm -5 , p = 0.030), and input impedance (2302 ±251 dyne • sec • cm -5 versus 2900 ±255 dyne • sec • cm -5 , p = 0.018). Characteristic impedance was not altered in 2-week-old pigs. These data indicate that Nω-nitro- L -arginine infusion resulted in pulmonary arteriolar vasoconstriction in 2-week-old pigs, but not in 48-hour-old pigs. This finding suggests that endothelium-derived relaxing factor does not modulate basal pulmonary arteriolar tone during the early newborn period, but does play a significant role in 2-week-old pigs. These data also suggest that the functional role for endothelium-derived relaxing factor is confined to the distal arteriolar pulmonary bed and does not extend to the larger proximal arterial vessels. (J THORAC CARDIOVASC SURG 1995;110:1486-92
An analyses of the status of landfill classification systems in developing countries: Sub Saharan Africa landfill experiences
Municipal solid waste (MSW) management remains a challenge in developing countries due to increasing waste generation, high costs associated with waste management and the structure of the containment systems implemented. This study analyses the classification of landfilling systems by using documented cases reported mainly in publications in waste management in relation to non-engineered landfilling systems/approved dumpsites in Sub Saharan African (SSA) countries from 2000 to 2018. The work identifies an existing system for the classification of landfill sites and utilises this system to determine the situation of landfill sites in SSA countries. Each article was categorised according to the main landfilling management practice reported: Uncontrolled dumping, semi controlled facility, medium controlled facility, medium/high-engineered facility or high state-of the-art facility. Findings suggested that 80% of the documented cases of landfill sites assessed in SSA countries were classified as level 0 or 1. The structure of the containment and controlled regime were identified by the focus group discussion participants as important predictors of possible strengths, weaknesses, opportunities and threats for the landfill sites considered. The study represents the first identifiable and comprehensive academic evaluation of landfill site classification based on site operations reported in the available peer reviewed literature. The information provides insight on the status of landfill sites in SSA countries with respect to the landfilling management practice and a baseline for alternative corrective measures
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Comparison of test and earthquake response modeling of a nuclear power plant containment building
The reactor building of a BWR plant was subjected to dynamic testing, a minor earthquake, and a strong earthquake at different times. Analytical models simulating each of these events were devised by previous investigators. A comparison of the characteristics of these models is made in this paper. The different modeling assumptions involved in the different simulation analyses restrict the validity of the models for general use and also narrow the comparison down to only a few modes. The dynamic tests successfully identified the first mode of the soil-structure system
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Effect of initial fluid-system pressures on the behavior of a rupture-disc pressure-relief device
Rupture disc assemblies are used in piping network systems as a pressure-relief device to protect the system from being exposed to excess pressures. Among the various disc assemblies, the reverse-buckling type is chosen for application in the Clinch River Breeder Reactor. This rupture-disc assembly consists of a portion of a thin spherical shell with its convex side subjected to the fluid system. The reverse-buckling type rupture disc assemblies have been used successfully in environments where the fluid is gas, i.e. highly compressible, and their performances have been judged as adequate in the liquid environment. To analyze the piping system, an analysis method is needed taking into consideration of the fluid/disc interaction, the nonlinear dynamic buckling phenomenon of the disc, and the possible cavitation of the fluid. A computer code SWAAM-I had been written at the Components Technology Division, Argonne National Laboratory. Among its many functions, one is to compute the response of 1-dimensional pressure pulse propagation including the effects of many different types of boundary conditions and possible pipe plasticity
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