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The Characteristics of the Granular State of Ceramic Particles in the Aspect of Producing Metal-Ceramic Composite Layers in Molds

Dulska A., Kilarski J., Studnicki A., Szajnar J.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

5--10

EN

The paper presents selected granular ceramic materials available on the Polish market. Their characteristics have been determined in the aspect on application in the production of iron alloy-ceramic composite. The possibility of obtaining a composite layer by means of bulk grains in molds of plates were considered, which was the foundation for experimental molds to be used in service tests. On the basis of obtaining results was stated that the knowledge of the characteristics of bulk grains enables the calculation of their quantity necessary for the composite production. When using the bulk grains the thickness of the composite layer is restricted by the thermal relations (cooler) and the physical phenomena (buoyancy, metal static pressure). Increasing amount of grains above definite condition causes surface defects in the castings. Each casting, due to its weight, shape and place of composite layer production requires an individual approach, both at the stage of formation and that of calculation of the required quantity of ceramic grains.

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Wpływ właściwości fizycznych na transport ciepła w złożu ziarnistym

Ratuszny P.

Przemysł Chemiczny

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2017

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T. 96, nr 9

1881--1883

PL

Piasek kwarcowy (1-1,6 mm) umieszczono w komorze pomiarowej ogrzewanej wodą o temp. 65°C i wyznaczono jego przewodnictwo cieplne. Mokry piasek o wilgotności 20% wykazywał większe współczynniki wymiany ciepła niż piasek suchy.

EN

Quartz sand (1-1.6 mm) was placed in a test chamber (350 × 350 × 700 mm) and studied for the thermal cond. under external heating with water (65°C). The wet sand (humidity 20%) showed a higher heat transfer coeff. than the dry one.

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(Bi,Pb)-Sr-Ca-Cu-O glass-ceramics - superconductor and granular metal

Gazda M., Kusz B., Murawski L., Stizza S., Natali R.

Optica Applicata

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2008

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Vol. 38, nr 1

153-161

EN

In the (Bi,Pb)-Sr-Ca-Cu-O system, materials of various electrical and superconducting properties may be produced by a glass-ceramic method. As a result of heat treatment, amorphous material partially crystallizes. It causes an increase in the size and/or the number of conducting grains and a decrease in the width of the insulating barriers between them. The resistivity of the samples containing small, weakly coupled grains in the normal state follows the exponential temperature dependence of resistivity, while in the samples with larger intergrain conductivities the dependence is logarithmic. Still stronger connections between the grains lead to linear or almost linear ?(T). The granular character of the (Bi,Pb)4Sr3Ca3Cu4Ox materials also influences their superconducting properties.

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Analogie i różnice właściwości cieczy magnetoreologicznych oraz granulatów umieszczonych w przestrzeni z podciśnieniem

Zalewski R., Bajkowski J.

Modelowanie Inżynierskie

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2008

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T. 5, nr 36

313-320

PL

W pracy omówiono podobieństwa i różnice zauważone w trakcie przeprowadzania badań eksperymentalnych urządzeń, pracujących na bazie cieczy MR oraz specjalnych struktur granulowanych. Zaprezentowano i omówiono przykładowe rezultaty doświadczalne uwzględniające wpływ czynnika sterującego na wybrane parametry pracy urządzeń.

EN

In this paper authors would like to introduce a new controllable structure, in some aspects similar to MR fluids, which is composed on the basis of granular material. Loose material is initially placed in a deformable hermetic encapsulation (basically made of soft polymer), equipped in a special valve. In the next step, an internal pressure is pumped out of the structure and so called “underpressure” is generated. This change in the structure appears as a considerable increase in apparent stiffness. Special granular structures, when high underpressure value is applied, seem to exhibit typical properties of solid (semisolid) state. The magnitude of this change is fully controlled by the range of generated internal underpressure. Typical experimental results conducted for both compared materials are discussed in this paper.