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Abstrakt

This paper presents exemplary exercise on the fundamentals of signal processing course which is offered for second year bachelor level students. Application of Field Programmable Analog Array (FPAA) for pulse amplitude modulation (PAM) exercise is described with signal processing laboratory. There are presented two methods for implementing PAM modulation and demodulation technique in FPAA module. Example configuration files are available form Authors’ web site.

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Autorzy i Afiliacje

Damian Grzechca
Lukas Chruszczyk

Abstrakt

Al-Ti-Si-W quaternary powders were mechanically synthesized by planetary ball milling; and further consolidated by spark plasma sintering. The nominal compositions of the quaternary alloys were designed to be Al60Ti30Si5W5 and Al45Ti40Si10W5 (wt.%). The microstructural evolution of intermetallic compounds in Al-Ti-Si-W alloys included titanium aluminide, titanium silicide, and ternary alloys (AlxTiy, TixSiy, and TixAly,Siz), whereas W was embedded in the Al-Ti matrix as a single phase. The phase composition and grain size distribution were investigated using electron backscatter diffraction analysis, in which refined and uniform microstructures (less than 0.3 μm) were attributed to severe plastic deformation and rapid densification of the pre-alloyed powders. The mechanical properties were correlated with the Al content in the quaternary alloys; a high hardness of 1014.6 ±73.5 kg/mm2 was observed.
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Autorzy i Afiliacje

Bum-Soon Park
1
Jae-Cheol Park
1
ORCID: ORCID
Hyun-Kuk Park
2
ORCID: ORCID
Jeong-Han Lee
3
ORCID: ORCID

  1. Korea Institute of Industrial Technology, Automotive Materials & Component R&D Group, 6, Cheomdan-gwagiro 208-gil, Buk-gu, Gwangju, 61012, Korea
  2. Korea Institute of Industrial Technology, Automotive Materials & Component R&D Group, 6, Cheomdan-gwagiro 208-gil, Buk-gu, Gwangju, 61012, Koreaqqq
  3. Korea Institute of Industrial Technology, Advanced Energy Materials and Components R&D Group, 33-1, Jungang-ro, Yangsan, Gyeongsangnam-do, 50623, Korea

Abstrakt

Mechanical properties of aluminum-silicon alloys are defined by condition of alloying components in the structure, i.e. plastic metallic matrix created from solid solution  on the basis of Al, as well as hard and brittle precipitations of silicon. Size and distribution of silicon crystals are the main factors having effect on field of practical applications of such alloys. Registration of crystallization processes of the alloys on stage of their preparation is directly connected with practical implementation of crystallization theory to controlling technological processes, enabling obtainment of suitable structure of the material and determining its usage for specific requirements. An attempt to evaluate correlation between values of characteristic points laying on crystallization curves and recorded with use of developed by the author TVDA method (commonly denominated as ATND method) is presented in the paper together with assessment of hardness of tested alloy. Basing on characteristic points from the TVDA method, hardness of EN AC-AlSi9Mg alloy modified with strontium has been described in the paper in a significant way by the first order polynomial.

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Autorzy i Afiliacje

J. Pezda

Abstrakt

Recently, the use of inorganic binders cured by heat as a progressive technology for large scale production of cores is widely discussed topic in aluminium foundries. As practical experiences show, knock-out properties of inorganic binders were significantly increased, although they cannot overcome organic based binder systems. This paper contains information about hot curing processes based on alkali silicate and geopolymer binder systems for core making. Main differences between hot cured geopolymers and hot cured alkali silicate based inorganic binders are discussed. Theory of geopolymer binder states, that binder bridge destruction is mainly of adhesive character. The main aim of this research paper was to examine binder bridge destruction of alkali silicate and geopolymer binder systems. In order to fulfil this objective, sample parts were submitted to defined thermal load, broken and by using SEM analysis, binder bridge destruction mechanism was observed. Results showed that geopolymer binder system examined within this investigation does not have mainly adhesive destruction of binder bridges, however the ratio of adhesive-cohesive to cohesive destruction is higher than by use of alkali silicate based binder systems, therefore better knock-out properties can be expected.

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Autorzy i Afiliacje

I. Vaskova
M. Conev

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