Time filter

Source Type

Roshanghias A.,CTR Carinthian Technology Research | Bruckner G.,CTR Carinthian Technology Research | Binder A.,CTR Carinthian Technology Research
Journal of Materials Science: Materials in Electronics | Year: 2017

A survey of high temperature die-attach solutions for lithium niobate (LiNbO3) single crystals was conducted and based on that three promising approaches; i.e. eutectic solder, silver sinter-paste and silver-loaded conductive adhesive; were proposed and investigated. A relatively low pressure span (0–4 MPa) was employed, aiming to mitigate the risk of fracture in the brittle die. The mechanical properties of the corresponding die-attach assemblies was examined by a die-shear tester and the reliability of the joints was assessed after isothermal aging at 300 °C. The micro-structural integrity of the bonding was also analyzed by cross-sectional microscopy. The results revealed that silver sinter paste die-attach possesses superior shear strength in comparison to the two other techniques. Cross-sectional failure analysis also indicated a ductile fracture mode throughout the bonding layer for silver-paste and adhesive joints, whereas in soldered assemblies a brittle fracture mode along the interfacial intermetallic compound layer was predominant. © 2017 Springer Science+Business Media New York


Ribeiro M.,CTR Carinthian Technology Research
Proceedings - 2016 UKSim-AMSS 18th International Conference on Computer Modelling and Simulation, UKSim 2016 | Year: 2016

To overcome the issue of the fast decay of the magnetic fields of a magnet over distance, a device constructed of a highly permeable material was developed, aiming to focus the magnetic fields at a sensing point, hence named "field focuser". This device allows designers to increase distances between magnet and sensor, chose weaker and cheaper magnets and work with simpler 1D magnetic sensors instead of more expensive 2 or 3D ones. This work focuses on the analysis of the influences and signal distortions that such a focusing device imposes in the system, aiming to highlight its performance. The findings were accomplished making use of FEM simulations and experimental validation, where the magnetic field on the presence and absence of the field focuser was analyzed. This paper aims to extend the knowledge on magnetic systems and help developers to understand limits and advantages of such setups. © 2016 IEEE.


Roshanghias A.,CTR Carinthian Technology Research | Bruckner G.,CTR Carinthian Technology Research | Binder A.,CTR Carinthian Technology Research
2016 IEEE CPMT Symposium Japan, ICSJ 2016 | Year: 2016

Lithium niobate (LiNbO3) single crystals are used as a promising piezoelectric material for high temperature sensors owing to its superior electromechanical coefficients and high frequency operation. The selection of materials and techniques for LiNbO3 die-Attach aiming for the service temperature up to 300 °C encounters many objectives and practical considerations, where the processing temperature should be kept below 450 °C due to the decomposition of the die. Among the few candidates of lead-free solders exist in this temperature range, gold-germanium (Au-12 wt. % Ge) eutectic solder has shown promising characteristics. Therefore, in the current study, LiNbO3 die-Attach to Hastelloy substrate with this solder was investigated. The mechanical properties of the corresponding assemblies were examined by a die-shear tester and the reliability of the joints has been assessed after thermal aging and thermal shock treatments at 300 °C. © 2016 IEEE.


Ribeiro M.,CTR Carinthian Technology Research | Ortner M.,CTR Carinthian Technology Research
2016 3rd International Conference on Electronic Design, ICED 2016 | Year: 2016

Magnetic position and orientation detection systems are used in various industrial applications. The large production quantities and high safety standards that such systems must often fulfill requires a stable magnetic field signal. In order to evaluate sensors and such reference signals, we introduce a custom made high precision test equipment for magnetic linear position and orientation detection, which can be used to analyze a permanent magnet's magnetic field behavior and a sensor's response to its excitation. A case study shows differences between datasheet values and actual component values for a commercial permanent magnet. The features and validation of the test equipment as well as measurement samples are presented and discussed. © 2016 IEEE.


Velik R.,CTR Carinthian Technology Research | Nicolay P.,CTR Carinthian Technology Research
Energy Conversion and Management | Year: 2014

Via the integration of renewable energy and storage technologies, buildings have started to change from passive (electricity) consumers to active prosumer microgrids. Along with this development come a shift from centralized to distributed production and consumption models as well as discussions about the introduction of variable demand-supply-driven grid electricity prices. Together with upcoming ICT and automation technologies, these developments open space to a wide range of novel energy management and energy trading possibilities to optimally use available energy resources. However, what is considered as an optimal energy management and trading strategy heavily depends on the individual objectives and needs of a microgrid operator. Accordingly, elaborating the most suitable strategy for each particular system configuration and operator need can become quite a complex and time-consuming task, which can massively benefit from computational support. In this article, we introduce a bio-inspired cognitive decision agent architecture for optimized, goal-specific energy management in (interconnected) microgrids, which are additionally connected to the main electricity grid. For evaluating the performance of the architecture, a number of test cases are specified targeting objectives like local photovoltaic energy consumption maximization and financial gain maximization. Obtained outcomes are compared against a modified simulating annealing optimization approach in terms of objective achievement and computational effort. Results demonstrate that the cognitive decision agent architecture yields improved optimization results in comparison to the state of the art reference method while at the same time requiring significantly less computation time. © 2014 Elsevier Ltd. All rights reserved.


Velik R.,CTR Carinthian Technology Research | Nicolay P.,CTR Carinthian Technology Research
Computers and Operations Research | Year: 2016

This article introduces a modified simulated annealing optimization approach for automatically determining optimal energy management strategies in grid-connected, storage-augmented, photovoltaics-supplied prosumer buildings and neighborhoods based on user-specific goals. For evaluating the modified simulated annealing optimizer, a number of test scenarios in the field of energy self-consumption maximization are defined and results are compared to a gradient descent and a total state space search approach. The benchmarking against these two reference methods demonstrates that the modified simulated annealing approach is able to find significantly better solutions than the gradient descent algorithm - being equal or very close to the global optimum - with significantly less computational effort and processing time than the total state space search approach. © 2015 Elsevier Ltd.


Velik R.,CTR Carinthian Technology Research
International Journal of Renewable Energy Research | Year: 2014

Increasing local photovoltaics (PV) utilization can reduce energy transportation losses and mitigate overvoltages and transformer overloadings. Strategies so far investigated and applied for this purpose are load shifting, the use of electricity storages, and the installation of east-west instead of south-oriented PV systems. In this article, we investigate and analyze the potential of a novel concept for the purpose of local PV consumption maximization based on neighbourhood energy exchange in combination with different cardinal directions of PV systems installed on buildings within a neighbourhood. Results demonstrate that this novel concept can lead to significantly increased local PV consumption rates in relation to today's default configurations without considerable extra costs or control efforts.


Chernev B.S.,University of Graz | Hirschl C.,CTR Carinthian Technology Research | Eder G.C.,OFI Austrian Research Institute for Chemistry and Technology
Applied Spectroscopy | Year: 2013

Vibrational spectroscopy was found to be a suitable method for the determination of the degree of cross-linking of ethylene vinyl acetate (EVA) polymers. Spectral changes in the Raman spectra of EVA with increasing lamination time (which equals increasing degree of crosslinking) were mainly detected in the CH vibrational regions, namely, in the relative intensities of the characteristic CH3 and CH2 bands. These spectral regions were chosen for a chemometric evaluation where a calibration was performed with the Raman spectra of reference EVA samples and the results obtained from corresponding thermal analysis (differential scanning calorimetry) and Soxhlet extraction data. These datasets were subsequently used to non-destructively determine the progress of cross-linking in EVA foils, embedded in various mini-modules by Raman microscopy. Thus, we could show that Raman spectroscopy is a highly interesting method for quality control in the production of photovoltaic (PV) modules. However, this approach is valid only for a given grade of EVA, meaning a demand for a new calibration when changing the supplier or the type of EVA used. In addition, the applicability of infrared spectroscopy for the determination of the degree of cross-linking was tested. A good correlation of the decrease in intensity of the characteristic cross-linker infrared bands with increasing progress of the cross-linking was found, as determined by reference methods. However, this analytical method requires taking samples of the EVA foils and is, thus, unsuitable for the non-destructive determination of the degree of cross-linking of the EVA encapsulated within a PV module. © 2013 Society for Applied Spectroscopy.


Velik R.,CTR Carinthian Technology Research | Nicolay P.,CTR Carinthian Technology Research
Applied Energy | Year: 2014

This article introduces a modified simulated annealing triple-optimizer for finding the optimal energy management strategy in terms of financial gain maximization in grid-connected, storage-augmented, photovoltaics-supplied prosumer building microgrids in a variable grid price scenario. For evaluating the performance of the optimizer, a number of test cases are specified offering different trading options to the prosumers. Obtained results are compared to a total state space search reference method and demonstrate that the simulated annealing approach was for all test cases able to find a globally optimal or close to optimal solution in significantly less computation time than the total space search reference method. © 2014 Elsevier Ltd.


Ribeiro M.,CTR Carinthian Technology Research | Ortner M.,CTR Carinthian Technology Research | Seger M.,CTR Carinthian Technology Research
Proceedings - International Conference on Industrial Automation, Information and Communications Technology, IAICT 2014 | Year: 2014

Magnetic systems provide powerful tools for contact free motion detection. Such systems are very robust, being capable of operating in harsh environments, e.g. in the presence of dirt and at high temperature, and have life-times of up to decades. Another advantage is that quasi-static applications, typical for the detection of mechanical motion, enable the measurement of magnetic fields from outside of a closed system, as the magnetic fields easily penetrate solid non-magnetic materials. On the other hand, the fast decay of the magnetic field of a magnet is a known characteristic and normally a limiting factor regarding distance between magnet and sensor. To overcome this issue, a device constructed of a highly permeable material is proposed, aiming to focus the magnetic field at a sensing point, hence named 'field focuser'. Similar concepts of magnetic field focusers have been proposed and are available in various geometrical designs [1, 2, 3]. Currently, there are several realizations of magnet-magnetic sensor systems where the motion of the magnet is detected by the change in field amplitude at the sensor. These systems include linear motion detection, axis rotation detection, complex composed motion detection and many others, which lead to a large range of industrial applications, especially in the automotive branch [4, 5]. This work aims to extend the knowledge on magnetic systems and help developers to understand limits and advantages of such setups. © 2014 IEEE.

Loading CTR Carinthian Technology Research collaborators
Loading CTR Carinthian Technology Research collaborators