14 research outputs found
Safety/reliability analyses of GA aircraft in design and certification stage in Czech republic
The purpose of the paper was to provide the reader with basic insight into practical problems solved in the Czech aerospace industry and with a list of requirements and recommendations of civil airworthiness regulations on the field of reliability. This includes a short historical introduction, a list of basic requirements, and recommendations of the regulations for different aircraft categories. The general aviation category (sport airplanes and small transport airplanes) is covered in more depth. Recommended procedures for reliability analyses are also covered (with a focus on the design and certification process), including a brief summary of their utilization in the Czech aerospace industry. Special attention is paid on the activities of the Brno University of Technology (and its Institute of Aerospace Engineering). A practical example of safety assessment based on an electronic avionic system for small GA aircraft is also provided.
First published online:Â 14 Oct 201
Diffuse neutron scattering in relaxor ferroelectric PbMg1/3Nb2/3O3
High energy resolution neutron spin-echo spectroscopy has been used to
measure intrinsic width of diffuse scattering discovered earlier in relaxor
ferroelectric crystals. The anisotropic and transverse components of the
scattering have been observed in different Brillouin zones. Both components are
found to be elastic within experimental accuracy of 1 eV. Possible
physical origin of the static-like behavior is discussed for each diffuse
scattering contribution.Comment: Submitted to the "Physical Chemistry and Chemical Physics"
(Proceedings of the QENA2004
Energy harvesting technologies for structural health monitoring of airplane components - a review
With the aim of increasing the efficiency of maintenance and fuel usage in airplanes, structural health monitoring (SHM) of critical composite structures is increasingly expected and required. The optimized usage of this concept is subject of intensive work in the framework of the EU COST Action CA18203 "Optimising Design for Inspection" (ODIN). In this context, a thorough review of a broad range of energy harvesting (EH) technologies to be potentially used as power sources for the acoustic emission and guided wave propagation sensors of the considered SHM systems, as well as for the respective data elaboration and wireless communication modules, is provided in this work. EH devices based on the usage of kinetic energy, thermal gradients, solar radiation, airflow, and other viable energy sources, proposed so far in the literature, are thus described with a critical review of the respective specific power levels, of their potential placement on airplanes, as well as the consequently necessary power management architectures. The guidelines provided for the selection of the most appropriate EH and power management technologies create the preconditions to develop a new class of autonomous sensor nodes for the in-process, non-destructive SHM of airplane components.The work of S. Zelenika, P. Gljušcic, E. Kamenar and Ž. Vrcan is partly enabled by using
the equipment funded via the EU European Regional Development Fund (ERDF) project no. RC.2.2.06-0001:
“Research Infrastructure for Campus-based Laboratories at the University of Rijeka (RISK)” and partly supported
by the University of Rijeka, Croatia, project uniri-tehnic-18-32 „Advanced mechatronics devices for smart
technological solutions“. Z. Hadas, P. Tofel and O. Ševecek acknowledge the support provided via the Czech
Science Foundation project GA19-17457S „Manufacturing and analysis of flexible piezoelectric layers for smart
engineering”. J. Hlinka, F. Ksica and O. Rubes gratefully acknowledge the financial support provided by the
ESIF, EU Operational Programme Research, Development and Education within the research project Center of
Advanced Aerospace Technology (Reg. No.: CZ.02.1.01/0.0/0.0/16_019/0000826) at the Faculty of Mechanical
Engineering, Brno University of Technology. V. Pakrashi would like to acknowledge UCD Energy Institute, Marine
and Renewable Energy Ireland (MaREI) centre Ireland, Strengthening Infrastructure Risk Assessment in the
Atlantic Area (SIRMA) Grant No. EAPA\826/2018, EU INTERREG Atlantic Area and Aquaculture Operations with
Reliable Flexible Shielding Technologies for Prevention of Infestation in Offshore and Coastal Areas (FLEXAQUA),
MarTera Era-Net cofund PBA/BIO/18/02 projects. The work of J.P.B. Silva is partially supported by the Portuguese
Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/FIS/04650/2020.
M. Mrlik gratefully acknowledges the support of the Ministry of Education, Youth and Sports of the Czech
Republic-DKRVO (RP/CPS/2020/003
Identification of major safety issues for a futuristic personal plane concept
The paper describes activities related to the safety assessment of a futuristic personal plane concept, done by researchers at the Institute of Aerospace Engineering (IAE), Brno University of Technology, as a part of the FP7 PPlane research project. Activities under the PPlane project were carried out in joint cooperation with an international research team led by ONERA (France). The aim of the FP7 EU project PPlane (Personal Plane) is to identify new potential concepts and technologies for future air transport, namely to create a future Personal Air Transport System (PATS). The personal air vehicle is understood to be analogous to a private car in terms of accessibility and ease of operation. Such a novel transportation system could help to reduce congestion on roads and enable more efficient transportation of passengers to their destinations. The introduction of PATS is a long-term goal which requires considerable progress beyond the current state-of-the-art technology as well as in related areas. The major enabling technology is believed to be a high level of automation in new air vehicles which would require either no or minor piloting skills of passengers.
The paper was presented at the READ 2013 conference in Brno (Czech Republic) and is reprinted with the permission of the conference organizers
Mixture Components Inference for Sparse Regression: Introduction and Application for Estimation of Neuronal Signal from fMRI BOLD
Sparse linear regression methods including the well-known LASSO and the
Dantzig selector have become ubiquitous in the engineering practice, including
in medical imaging. Among other tasks, they have been successfully applied for
the estimation of neuronal activity from functional magnetic resonance data
without prior knowledge of the stimulus or activation timing, utilizing an
approximate knowledge of the hemodynamic response to local neuronal activity.
These methods work by generating a parametric family of solutions with
different sparsity, among which an ultimate choice is made using an information
criteria. We propose a novel approach, that instead of selecting a single
option from the family of regularized solutions, utilizes the whole family of
such sparse regression solutions. Namely, their ensemble provides a first
approximation of probability of activation at each time-point, and together
with the conditional neuronal activity distributions estimated with the theory
of mixtures with varying concentrations, they serve as the inputs to a Bayes
classifier eventually deciding on the verity of activation at each time-point.
We show in extensive numerical simulations that this new method performs
favourably in comparison with standard approaches in a range of realistic
scenarios. This is mainly due to the avoidance of overfitting and underfitting
that commonly plague the solutions based on sparse regression combined with
model selection methods, including the corrected Akaike Information Criterion.
This advantage is finally documented in selected fMRI task datasets
Attachment of trianglamines to silicon wafers, chiral recognition by chemical force microscopy
International audienc
Domain-wall engineering and topological defects in ferroelectric and ferroelastic materials
Ferroelectric and ferroelastic domain walls are 2D topological defects with thicknesses approaching the unit cell level. When this spatial confinement is combined with observations of emergent functional properties, such as polarity in non-polar systems or electrical conductivity in otherwise insulating materials, it becomes clear that domain walls represent new and exciting objects in matter. In this Review, we discuss the exotic polarization profiles that can arise at domain walls with multiple order parameters and the different mechanisms that lead to domain-wall polarity in non-polar ferroelastic materials. The emergence of energetically degenerate variants of the domain walls themselves suggests the existence of interesting quasi-1D topological defects within such walls. We also provide an overview of the general notions that have been postulated as fundamental mechanisms responsible for domain-wall conduction in ferroelectrics. We then discuss the prospect of combining domain walls with transition regions observed at phase boundaries, homo- and heterointerfaces, and other quasi-2D objects, enabling emergent properties beyond those available in today’s topological systems