Atomic ordering and magnetism in L10 ordered FePd alloys

Intermetallic compounds due to their promising corrosion resistance and high-temperature mechanical strength give hope for their application as high-temperature structural materials. Inter-metallics of L1₀ type structure in recent years in addition have attracted great interest as potential recording media. These alloys are ferromagnetic and display marked mechanical and magnetic anisotropy with the tetragonal c-axis of the ordered domains as the “easy axis” of magnetization High-density magnetic recording may be achieved by a preferential domain orientation with the c-axis perpendicular to the surface, if these materials can be stabilized as low-dimensional magnetic structures. Knowledge of kinetic parameters, that determine alloy stability is essential for alloy design. technical application, and performance of materials. We used FePd as a model system for this class of L1₀-ordered intermetallics and have studied the changes of long-range order during heat treatments in the bulk and in thin films produced by different techniques. Results of X-ray diffraction (XRD). resistivity measurement. Mößbauer spectroscopy, and measurement of magnetization in both geometries are compared.     

Optimization of gas injection conditions during deposition of AlN layers by novel reactive GIMS method

In 2011, we proposed a novel magnetron sputtering method. It involved the use of pulsed injection of working gas for the initiation and control of gas discharge during reactive sputtering of an AlN layer (Gas Injection Magnetron Sputtering — GIMS). Unfortunately, the presence of Al-Al bonds was found in XPS spectra of the AlN layers deposited by GIMS onto Si substrate. Our studies reported in this paper proved that the synchronization of time duration of the pulses of both gas injection and applied voltage, resulted in the elimination of Al-Al bonds in the AlN layer material, which was confirmed by the XPS studies. In our opinion the most probable reason of Al-Al bonds in the AlN layers deposited by the GIMS was the self-sputtering of the Al target in the final stage of the pulsed discharge.     

Multivariate discrimination of wines with respect to their grape varieties and vintages

The primary focus of the European Union funded project entitled “Establishing a WINE Data Bank for analytical parameters for wines from Third Countries” (WINE-DB project, G6RD-CT-2001-00646-WINE-DB) was the discrimination of wine samples with respect to their geographical origin using only a few chemical parameters. Taking a step further, we have investigated the possibility of discriminating the wines in the data bank according to their harvesting seasons and grape varieties. Several chemometric methods were carefully selected and evaluated for this purpose. These were discriminant partial least squares, classification and regression trees, uninformative variable elimination discriminant partial least squares and neuro-fuzzy systems. With classification and regression trees, it was possible to identify a few chemical parameters including isotopic ratios (e.g. δ¹⁸O), biogenic amines and rare earth elements that discriminate between vintages and some grape varieties for wines produced in a particular country such as Czech Republic, Hungary, Romania or South Africa. These parameters can be used in evaluating the authenticity of wines.     

Performance Problems and Structural Retrofit Analysis of Existing BCTs

Automobile accident reports and full-scale crash tests of existing breakaway cable terminals (BCTs) indicated their poor performance during end-on impacts. This paper presents results of a feasibility study, which was conducted to identify problems with existing BCTs. The nonlinear, explicit, dynamic finite-element code LS-DYNA was used in the investigation of BCT design problems. Several problems were identified in the past during the full-scale crash tests. These problems became clearly visible when computational mechanics analyses were used. In addition to severe vehicle damage, vehicular impact induced dangerous, large deceleration peaks and uncontrolled vehicle trajectories. Analysis of actual crash tests and LS-DYNA data led to the conclusion that the terminal is too stiff along its longitudinal direction and fails to smoothly control dissipation of the vehicle kinetic energy. Therefore, the major objective of the research was to soften the existing system by weakening the rail in strategically located areas. The paper describes the design retrofit process, which was continuously guided by computational mechanics analyses. Specific retrofit recommendations emerged at the end of this process and they are described in the paper. Full-scale crash tests are recommended to confirm expected benefits of the proposed retrofit.     

Influence of absorbed dose and deep traps on thermoluminescence response: a numerical simulation

Numerical simulations based on standard rate equations are carried out to study the dependence of the thermoluminescence (TL) response on the absorbed dose. The model, which includes thermally stimulated exoelectronic emission (TSEE), uses three electron traps--two active and one thermally disconnected (TD)--and one deep hole trap acting as a recombination centre. After instantaneous creation of a given dose of electron-hole pairs, one first follows isothermal recombination and trap filling before simulating the TL readout. Influence of TD traps and specific effects due to trap saturation are illustrated. A systematic study of the TL response is performed in wide ranges of the determining parameters. The dose dependence is found to be quadratic, linear or intermediate according to their relative values. Results are explained in terms of recombination-trapping competition, trap occupancy and in relation with the presence of TSEE.     

Metallic nanobowls by galvanic replacement reaction on heterodimeric nanoparticles

Well-defined metallic nanobowls can be prepared by extending the concept of a protecting group to colloidal synthesis. Magnetic nanoparticles are employed as "protecting groups" during the galvanic replacement of silver with gold. The replacement reaction is accompanied by spontantous dissociation of the protecting groups, leaving behind metallic nanobowls.     

Tuning and implementation variants of discrete-time ADRC

Practical implementations of active disturbance rejection control (ADRC) will almost always take place in discretized form. Since applications may have quite different needs regarding their discrete-time controllers, this article summarizes and extends the available set of ADRC implementations to provide a suitable variant for as many as possible use cases. In doing so, the gap between quasi-continuous and discrete-time controller tuning is closed for applications with low sampling frequencies. The main contribution of this article is the derivation of three different discrete-time implementations of error-based ADRC. It is shown that these are almost one-to-one counterparts of existing output-based implementations, to the point where transfer functions and coefficients can be reused in unaltered form. In this way, error-based implementations become firmly rooted in the established landscape of discrete-time ADRC. Furthermore, it becomes possible to equip error-based variants with windup protection abilities known from output-based ADRC.