810 research outputs found
Identification and assessment of the need to improve the operation of production systems in the metal sector enterprises
In this paper an attempt was made to identify the areas of metal products manufacturing processes that require improvement. Determination of such areas may become a source of a lot of valuable information for the enterprise, enabling the development of its improvement directions. The results of survey allowed also to define a model of implementation importance for tasks contributing to the metal sector enterprises improvement
Mean and Flux Horizontal Variability of Virtual Potential Temperature, Moisture, and Carbon Dioxide: Aircraft Observations and LES Study
The effects of the horizontal variability of surface properties on the turbulent fluxes of virtual potential temperature, moisture, and carbon dioxide are investigated by combining aircraft observations with large-eddy simulations (LESs). Daytime fair-weather aircraft measurements from the 2002 International H2O Project¿s 45-km Eastern Track over mixed grassland and winter wheat in southeast Kansas reveal that the western part of the atmospheric boundary layer was warmer and drier than the eastern part, with higher values of carbon dioxide to the east. The temperature and specific humidity patterns are consistent with the pattern of surface fluxes produced by the High-Resolution Land Data Assimilation System. However, the observed turbulent fluxes of virtual potential temperature, moisture, and carbon dioxide, computed as a function of longitude along the flight track, do not show a clear east¿west trend. Rather, the fluxes at 70 m above ground level related better to the surface variability quantified in terms of the normalized differential vegetation index (NDVI), with strong correlation between carbon dioxide fluxes and NDVI
Magnetic properties of Sn/1-x/Cr/x/Te diluted magnetic semiconductors
We present the studies of Sn/1-x/Cr/x/Te semimagnetic semiconductors with
chemical composition x ranging from 0.004 to 0.012. The structural
characterization indicates that even at low average Cr-content x < ?0.012, the
aggregation into micrometer size clusters appears in our samples. The magnetic
properties are affected by the presence of clusters. In all our samples we
observe the transition into the ordered state at temperatures between 130 and
140 K. The analysis of both static and dynamic magnetic susceptibility data
indicates that the spin-glass-like state is observed in our samples. The
addition of Cr to the alloy seems to shift the spin-glass-like transition from
130 K for x = 0.004 to 140 K for x = 0.012.Comment: 4 pages, 4 figure
Utjecaj promjena temperature plinova izgaranja tijekom strujanja oko horizontalnog cilindra na lokalni Nusseltov broj
The article the influence of changes of combustion gas temperature during flow around of horizontal cylinder on local Nu number was presented. In order to test an influence of effect waste gas temperature cycle of experimental investigations were conducted. Experimental tests were carried out on a properly designed measuring cylinder furnished with a number of thermocouples embedded along the cylinder perimeter. The cylinder was made from stainless steel of known thermal conductivity, and was cooled on the outer side through a water cooling system. The cylinder was placed horizontally in a heating chamber equipped with an axially positioned gas burner fired with natural gas. Gas and air feeds were regulated with control valves, based on combustion gas analyzer data.U članku se prezentira utjecaj promjena temperature plinova izgaranja tijekom strujanja oko horizontalnog cilindra na lokalni Nusseltov broj. U svrhu ispitivanja utjecaja temperature otpadnih plinova izvedena je serija eksperimenata. Eksperimenti su izvršeni na propisno izvedenom mjernom cilindru na kojeg su po opsegu postavljeni termoparovi. Cilindar je načinjen od nehrđajućeg čelika poznate toplinske provodnosti i s vanjske strane hlađen pomoću rashladnog sustava s vodom. Cilindar je smješten horizontalno u komoru za zagrijavanje opremeljnu s aksijalno postavljenim plinskim plamenikom na prirodni plin. Dovod plina i zraka regulira se pomoću kontrolnih ventila, temeljen na podacima iz analizatora dimnih plinova
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