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Paul A. Smith and Gareth G. James

(2008) GSS MAC 15 - minutes. Available from http://webarchive.nationalarchives.gov.uk/20160105160709/http://www.ons.gov.uk/ons/guide-method/method-quality/advisory-committee/2008-2011/15th-meeting/gss-mac-fifteenthmeeting-minutes.pdf (accessed 15 January 2017). Hughes, J.C. 2008. “SIC 2007: Implementation in ONS.” Economic and Labour Market Review 2: 41-44. Hundepool, A., J. Domingo-Ferrer, L. Franconi, S. Giessing, E. Schulte Nordholt, K. Spicer, and P.-P. de Wolf. 2012. Statistical Disclosure Control. Chichester: Wiley. Doi: http

Open access

B. Kalandyk and R. Zapała

Abstract

The study attempts to determine the impact of the high-manganese cast steel strain hardening on its abrasion wear resistance in a mixture of SiC and water prepared in accordance with ASTM G75. For tests, the high-manganese cast steel containing 10.7, 17.9 and 20.02% Mn was selected. The results of microstructure examinations and abrasion wear resistance tests carried out on the material in non-hardened condition and after strain hardening with a force of 539.55kN were disclosed. Additionally, the surface of samples after a 16-hour cycle of abrasion tests was examined. Moreover, based on the obtained results, the effect of different contents of Mn in cast steel was studied, mainly in terms of its impact on the abrasion wear resistance. The results obtained on the tested materials were compared with the results obtained on the low-alloyed abrasion wear-resistant cast steel L35GSM.

Open access

A. J. Dolata, M. Dyzia and S. Boczkal

Abstract

The aim of the work was to perform adequate selection of the phase composition of the composite designated for permanent - mould casting air compressor pistons. The hybrid composites based on AlSi7Mg matrix alloy reinforced with mixture of silicon carbide (SiC) and glassy carbon (Cg) particles were fabricated by the stir casting method. It has been shown that the proper selection of chemical composition of matrix alloy and its modification by used magnesium and strontium additions gives possibility to obtain both the advantageous casting properties of composite suspensions as well as good bonding between particles reinforcements and matrix.

Open access

Miroslav Mikolášek, Ján Jakaboviš, Vlastimil Řeháček, Ladislav Harmatha and Robert Andok

Abstract

In this paper we present the capacitance study of the intrinsic amorphous silicon/crystalline silicon heterostructure with the aim to gain insight on the heterointerface properties of a passivated silicon heterojunction solar cell. It is shown that due to the high density of defect states in the amorphous layer the structure has to be analyzed as a heterojunction. Using the analysis, the following values have been determined: conduction-band offset of 0.13 eV, electron affinity of 3.92 eV, and density of defect states in the intrinsic amorphous silicon being that of 4.14 X 1021m—3.

Open access

Sebastian Skoczypiec, Magdalena Machno and Wojciech Bizoń

Abstract

In the first part of the article the review of ceramic materials drilling possibilities was presented. Among the described methods special attention is paid to electrodischarge drilling. This process have especially been predicted for machining difficult-to-cut electrically conductive materials. The second part consist of the results analysis of electrodischarge microdrilling of siliconized silicon carbide. The experiment involves the impact of current amplitude, discharge voltage and pulse time on the hole depth, side gap, linear tool wear and mean drilling speed. The results shows that electrodischarge drilling is a good alternative when machining inhomogeneous ceramic materials and gives possibility to drill high aspect ratio holes with relatively high efficiency (the drilling speed >2 mm/min).

Open access

Jacek Rąbkowski

References [1] Bakowski M., Status and prospects of SiC power devices. IEEJ Trans. Industry Applications 126(4): 391-399 (2006). [2] Friedrichs P., Silicon carbide power semiconductors - new opportunities for high efficiency. Proc. 3rd IEEE Conference on Industrial Electronics and Applications, ICIEA 2008, pp. 1770-1774 (2008). [3] Kaminski N., State of the art and future of wide band-gap devices. Proc. of 13th European Conference on Power Electronics and Applications, EPE (2009

Open access

Vahid Monfared

Abstract

The present work presents a new approach based on neural network prediction for simple and fast estimation of the creep plastic behaviour of the short fiber composites. Also, this approach is proposed to reduce the solution procedure. Moreover, as a significant application of the method, shuttles and spaceships, turbine blades and discs are generally subjected to the creep effects. Consequently, analysis of the creep phenomenon is required and vital in different industries. Analysis of the creep behaviour is required for failure, fracture, fatigue, and creep resistance of the optoelectronic/photonic composites, and sensors. One of the main applications of the present work is in designing the composites with optical fibers and devices. At last, a good agreement is seen among the present prediction by neural network approach, finite element method (FEM), and the experimental results.

Open access

R. Lakomá and L. Čamek

Abstract

This report addresses some chosen statistical methods that could be used to confirm and set up the required functions of technology in foundry companies where parts are cast by the low-wax casting method, whereas these chosen statistical methods are intended to reduce poor quality of produced parts. This research was made on a practical example. Utilization of hypothesis testing methods was examined in order to confirm technological parameters having some influence on the products quality. The data were compared before and after the implementation of changes aimed at reduction of poor quality produced parts in the wax department. The results confirmed that the implemented change had a statistically conclusive influence.

Open access

Tomasz Tarczewski, Łukasz J. Niewiara and Lech M. Grzesiak

Abstract

The article presents an auto-tuning method of state feedback voltage controller for DC-DC power converter. The penalty matrices employed for calculation of controller’s coefficients were obtained by using nature-inspired artificial bee colony (ABC) optimization algorithm. This overcomes the main drawback of state feedback control related to time-consuming trial-and-error tuning procedure. The optimization algorithm takes into account constraints of selected state and control variables of DC-DC power converter. In order to meet all control objectives (i.e., fast voltage response and chattering-free control signal) an appropriate performance index is proposed. Proper selection of state feedback controller (SFC) coefficients is proven by simulation and experimental tests of DC-DC power converter.