Ecological effect of modernization of a metallurgical furnace

In the paper, a feasible ecological effect of modernization of a conventional metallurgical furnace intended for charge material preheating before plastic working processes is described. The modernization activities involved replacement of the previous recuperator, the negative pressure control system of the furnace and a proposal for application of modern low emission burners. The suggested design of a recuperator with a higher energy recovery level due to a decreased flue gas temperature will contribute to reduced consumption of electrical energy that is necessary for the extraction ventilator drive. The modernization activities led to decreased total process-induced CO2 emissions resulting from lower consumption of gas and electrical energy (nearly 11 % in relation to the state before the modernization)

Technical and technologicAl solutions in development of FeSiAl alloys production from industrial wastes in submerged ARC furnace (SAF)

This article presents a description of the carbothermic process concerning production of iron-silicon-aluminum alloys with 55 to 75 wt. % of silicon and 4 to 20 wt. % of aluminum in industrial conditions. For the process, mining waste resulted from mechanical processing of coal being the source of silicon and aluminum compounds as well as high-ash fine coal as a reducer was used. A modern technological line for FeSiAl smelting was described, consisting of a SAF (fitted with two 7,75 MVA three-phase transformers and six self-baking electrodes) to ensure optimum power distribution in the furnace. In addition, technical and technological parameters of the process were presented with a particular emphasis placed on Al and Si yields

Modelling of hydrodynamic phenomena occurring in refining ladles for high-carbon Fe-Si alloys

This paper presents the results of research conducted with the use of water physical model of refining ladle for production of high-carbon FeSi alloys. The purpose of the research was to determine the possibilities to enhance the efficiency of the production process by using combined gas injection into the bath. The research involved analysis of four variants of the experiment. Those variants varied in terms of the location of a purging plug fitted in the model bottom and the application of immersion lance to support the process. The research involved the analysis of changes in the hydrodynamic effects in the ladle model occurring as a result of the gas injection. The tests consisted in a qualitative analysis (process visualisation) in order to identify the movement of the modelling liquid and the mechanism of gas bubbles behaviour in the liquid

Giant cardiac tumours in the newborn: an unusual image

Primary heart tumours in the paediatric population are very rare and they range from 0.01% to 0.04%. Most are benign lesions of which about half are rhabdomyomas. Rhabdomyoma tumour diagnosis is associated with a 75–80% risk of tuberous sclerosis complex (TSC). TSC are characterised with numerous changes of hamartoma-type located in the brain, kidneys, skin and other organs including the heart. More than two-thirds of newborns with TSC present rhabdomyomas in the heart. These changes may be asymptomatic, but in some cases they may cause heart failure, arrhythmias and death. We present a case report of an infant with giant rhabdomyoma tumours in the course of TSC

Modelling of hydrodynamic phenomena occurring in refining ladles for high-carbon Fe-Si alloys

This paper presents the results of research conducted with the use of water physical model of refining ladle for production of high-carbon FeSi alloys. The purpose of the research was to determine the possibilities to enhance the efficiency of the production process by using combined gas injection into the bath. The research involved analysis of four variants of the experiment. Those variants varied in terms of the location of a purging plug fitted in the model bottom and the application of immersion lance to support the process. The research involved the analysis of changes in the hydrodynamic effects in the ladle model occurring as a result of the gas injection. The tests consisted in a qualitative analysis (process visualisation) in order to identify the movement of the modelling liquid and the mechanism of gas bubbles behaviour in the liquid

Effect of Seed Rate of Trifolium repens in Pasture Overdrilling

In the region of Wielkopolska, unfavourable climatic conditions, particularly periodical shortage of precipitation, have contributed to a rapid degradation of pastures in dairy farms. In grass-clover mixtures Trifolium repens (Tr) is found to disappear very quickly from the sward. In consequence the DM yield and herbage quality in summer is low. One of the methods of improving of pasture sward and reducing the seasonality of forage production is overdrilling (OD). Many factors affect the success of this undertaking (Sheldrick 2000). This research investigated the response to one easily adjustable factor, that of seed rate (SR)

Quasar Selection Based on Photometric Variability

We develop a method for separating quasars from other variable point sources using SDSS Stripe 82 light curve data for ~10,000 variable objects. To statistically describe quasar variability, we use a damped random walk model parametrized by a damping time scale, tau, and an asymptotic amplitude (structure function), SF_inf. With the aid of an SDSS spectroscopically confirmed quasar sample, we demonstrate that variability selection in typical extragalactic fields with low stellar density can deliver complete samples with reasonable purity (or efficiency, E). Compared to a selection method based solely on the slope of the structure function, the inclusion of the tau information boosts E from 60% to 75% while maintaining a highly complete sample (98%) even in the absence of color information. For a completeness of C=90%, E is boosted from 80% to 85%. Conversely, C improves from 90% to 97% while maintaining E=80% when imposing a lower limit on tau. With the aid of color selection, the purity can be further boosted to 96%, with C= 93%. Hence, selection methods based on variability will play an important role in the selection of quasars with data provided by upcoming large sky surveys, such as Pan-STARRS and the Large Synoptic Survey Telescope (LSST). For a typical (simulated) LSST cadence over 10 years and a photometric accuracy of 0.03 mag (achieved at i~22), C is expected to be 88% for a simple sample selection criterion of tau>100 days. In summary, given an adequate survey cadence, photometric variability provides an even better method than color selection for separating quasars from stars.Comment: (v2) 50 pages, accepted to Ap