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Olgierd Hryniewicz

. (1996a). Estimation from truncated lifetime data with supplementary information on covariates and censoring times. Biometrika , 83(4), 747-761. Lawless J. F. (1982). Statistical Models and Methods for Lifetime Data. John Wiley and Sons, New York. Lawless J. F. (2003). Statistical Models and Methods for Lifetime Data. Second Edition. John Wiley and Sons, New York.

Open access

Olgierd Hryniewicz

.F. (1996). Estimation from truncated lifetime data with supplementary information on covariates and censoring times. Biometrika , v.83, no.4, p.747-761. Lawless J.F. (1982). Statistical Models and Methods for Lifetime Data. John Wiley and Sons, New York. Lawless J.F. (2003). Statistical Models and Methods for Lifetime Data. Second Edition. John Wiley and Sons, New York.

Open access

Xiaokai Meng, Zhiqiang Wang and Guofeng Li

thermoplastic composites and constituents , Time Dependent Constitutive Behavior and Fracture/Failure Processes, vol. 3, pp. 139-146 (2011). [9] Celina M., Gillen K.T., Assink R.A., Accelerated aging and lifetime prediction: review of non-Arrhenius behavior due to two competing processes , Polymer Degradation and Stability, vol. 90, no. 3, pp. 395-404(2005).

Open access

Jana Simeg Veternikova, Martin Fides, Jarmila Degmova, Stanislav Sojak, Martin Petriska and Vladimir Slugen

. Pease, “The displacement of atoms solids by radiation”, Rep. Progr. Phys. , 18 (1955) 151. [10] M. Petriska, A. Zeman, V. Slugen, V. Krsjak, S. Sojak, DEBARBERIS and L, “Application of FastDigitizer Card Acqiris DP240 Positron Lifetime Spectroscopy”, Phys. Stat. Solidi. , C 60 (2009) 2465 2467. [11] V. Krsjak, “Positron annihilation study of advanced nuclear reactor materials”, Doctoral thesis , FEI STU, Bratislava, September, 2008. [12] W. C. Oliver and G. M. Pharr, “An improved technique for determining hardness and elastic modulus using load

Open access

Patrik Novák, Aleksandr Gokhman, Edmund Dobročka, Jozef Bokor and Stanislav Pecko

Materials Science 33 No. 4 (2005), 491–498. [7] BALLO, P.—DEGMOVÁ, J.—SLUGEŇ, V. : Grain boundary sliding and migration in copper: Vacancy effect, Physical Review B 72 No. 6 (2005), 064118–064118. [8] KRŠJAK, V.—SLUGEŇ, V.—PETRISKA, M.—SOJAK, S. — EGGER, W. : Microstructural study of He-implanted Fe-Cr alloys with the use of conventional lifetime technique and pulsed low energy positron beam, Physica Status Solidi C 6 No. 11 (2009), 2339–2341, Special Issue: 15th International Conference on Positron Annihilation (ICPA-15). [9] ZIEGLER, J. F

Open access

Andrea Haringová, Karol Stračár and Karol Prikkel

Abstract

The article deals with the question of physical parameters that could positively influence the overall lifetime of hip joint endoprosthesis. As the important physical parameter it was selected the coefficient of friction. The contribution offers possibilities how to decrease the coefficient of friction and experimentally test these assumptions

Open access

Tariq Taleb and Mejdi Kaddour

Abstract

Extending the lifetime of wireless sensor networks (WSNs) while delivering the expected level of service remains a hot research topic. Clustering has been identified in the literature as one of the primary means to save communication energy. In this paper, we argue that hierarchical agglomerative clustering (HAC) provides a suitable foundation for designing highly energy efficient communication protocols for WSNs. To this end, we study a new mechanism for selecting cluster heads (CHs) based both on the physical location of the sensors and their residual energy. Furthermore, we study different patterns of communications between the CHs and the base station depending on the possible transmission ranges and the ability of the sensors to act as traffic relays. Simulation results show that our proposed clustering and communication schemes outperform well-knows existing approaches by comfortable margins. In particular, networks lifetime is increased by more than 60% compared to LEACH and HEED, and by more than 30% compared to K-means clustering.

Open access

Peter Haas, Milan Kadnár, Juraj Rusnák, František Tóth and Dušan Nógli

Abstract

Contact wear caused by electric arc during electric contact make (cut-in) and break (cut-out) has the direct impact on the contact lifetime. The RC element wired parallelly to the contact will eliminate or reduce the arcing and subsequently extend the lifetime. Comparative tests of the two sets of identical Danfoss 077B electromechanical thermostats have been carried out. In the first batch, standard thermostats were tested. In the second batch, the same thermostat types, but with RC elements wired parallel to thermostats main contacts were tested. Measurement has not proven any improvement of the contact wear. Temperature drift and change of the critical dimension caused by contact wear were very similar in the both cases. Thus, the application of RC element is considered not reasonable measure for reduction of contact wear of electromechanical thermostats.

Open access

Mateusz Torbicki

Abstract

The conditional safety functions at the climate-weather particular states and the unconditional safety functions of the port oil piping transportation system area and the maritime ferry, the mean values and the variances of those systems unconditional lifetimes and other safety indicators are determined. Those safety indicators, considering impact of the climate-weather change process, are evaluated for the piping system operating at under water Baltic sea area and for the maritime ferry operating at Gdynia Port area.

Open access

Maciej Malicki and Bartosz Madejski

Abstract

To prevent failure of machine components it is necessary to measure material damage generated in a component throughout its entire lifetime. Damage can be quantified by means of damage parameters. This paper considers the usefulness of hardness measurements to evaluate damage parameter in Inconel 718. Vickers hardness tests were performed on a specimen with a variable cross section area after tensile testing. The specimen’s geometry enabled the evaluation of damage parameter in respect of hardness measurements made on one individual specimen.