The main bulk density representation in the molding material is opening material, refractory granular material with a particle size of 0.02
mm. It forms a shell molds and cores, and therefore in addition to activating the surface of the grain is one of the most important features
angularity and particle size of grains. These last two features specify the porosity and therefore the permeability of the mixture, and
thermal dilatation of tension from braking dilation, the thermal conductivity of the mixture and even largely affect the strength of molds
and cores, and thus the surface quality of castings. [1]
Today foundries, which use the cast iron for produce of casts, are struggling with surface defects on the casts. One of these defects are
veining. They can be eliminated in several ways. Veining are foundry defects, which arise as a result of tensions generated at the interface
of the mold and metal. This tension also arises due to abrupt thermal expansion of silica sand and is therefore in the development of
veining on the surface of casts deal primarily influences and characteristics of the filler material – opening material in the production of
iron castings.
The present elaboration gives the results of investigations carried out by the VLF method in September. 1980. in Fuglebersletta, in the Hornsund Fiord area, Spitsbergen. The aim of the investigations was to localize precisely the ore-bearing veins and to trace their course.
The current casting production of castings brings increased demands for surface and internal quality of the castings. Important factors, that influence the quality of casted components, are the materials used for the manufacture of moulds and cores. For the preparation and production of moulds and cores, in order to achieve a low level of casting defects, then it used a high quality input materials, including various types of sands, modified binders, additives, etc. However, even the most expensive raw materials are not a guarantee to achieve the quality of production.
It is always necessary to choose the appropriate combination of input material together with an appropriate proposal for the way of the production, the metallurgical treatment of cast alloy, etc. The aim of this paper is to establish the basic principles for the selection of the base core mixtures components – sands to eliminate defects from the tension, specifically veining. Various silica sand, which are commonly used in foundries of Middle Europe region, were selected and tested.
Anatomical variations of the inferior vena cava, including the double inferior vena cava or isolated left inferior vena cava, are uncommon and of great clinical importance. Inferior vena cava variations signify predisposition to deep vein thrombosis and may complicate retroperitoneal surgeries including abdominal aortic surgery. Failure to recognize such variations may predispose a patient to life- threatening complications. This prospective anatomical study assessed 129 cadavers for variations of the inferior vena cava. One of the 129 cadavers (0.78%) possessed a double inferior vena cava and none (0%) possessed an isolated left inferior vena cava. The left-sided inferior vena cava was of a larger diameter than that of the right-sided inferior vena cava — opposite of what would be seen in a Type III duplication. Therefore, this observation expands the three-type classification system to include a Type IV duplication.
Finger vein biometric systems become increasingly more popular because they offer higher security comparing to other authentication solutions with respect to positive persons experience. Those systems operate on near infrared light (NIR) in wavelength range from around 700 to 1000 nm, however dedicated research to determine impact of NIR lighting on biometric system effectiveness has not been conducted and presented in the literature ever before. In this paper the study of correlation between wavelengths in NIR spectra and effectiveness of person identification in a biometric system is presented. To achieve that goal, a new model of image acquisition system allowing change of light wavelengths has been created and NIR finger vein dataset containing 11 556 images was established. Furthermore, this model was used to perform experimental work and proof that some NIR wavelengths better suit for vein patterns acquisition, allowing to increase the recognition effectiveness of finger vein biometric systems.