Upper Austria University of Applied Sciences

Wels, Austria

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Liu X.,Florida State University | Aichhorn A.,Upper Austria University of Applied Sciences | Liu L.,Florida State University | Li H.,Florida State University
IEEE Transactions on Smart Grid | Year: 2012

This paper proposes a coordinated control of distributed energy storage system (ESS) with traditional voltage regulators including the on-load tap changer transformers (OLTC) and step voltage regulators (SVR) to solve the voltage rise problem caused by the high photovoltaic (PV) penetration in the low-voltage distribution network. The main objective of this coordinated control is to relieve the tap changer transformer operation stress, shave the distribution network peak load and decrease the transmission and distribution resistive power losses under high solar power penetration. The proposed control method limits the energy storage depth of discharge in order to meet a more than ten-year cycle life. A benchmark distribution network model was developed in the Real Time Digital Simulator (RTDS) and the simulation results from the studied cases verified the proposed coordinated control strategy. The experimental implementation of proposed control algorithms were developed based on a power hardware-in-the-loop (PHIL) test bed with a 22 kWh ESS, a smart meter, Labview controller, and RTDS. The experimental results were consistent with those obtained from simulation study. © 2012 IEEE.

Suess D.,Vienna University of Technology | Schrefl T.,Upper Austria University of Applied Sciences
Applied Physics Letters | Year: 2013

Heat assisted recording is believed as a key future recording technology. In the work of H. J. Richter [J. Appl. Phys. 111, 033909 (2012)] it is stated that storage densities will be limited to 15-20 Tbit/in2 due to thermally induced write errors. In this letter we propose a composite structure consisting of two materials with different Curie temperatures. In this composite material the thermal write error is negligible up to areal densities of about 50-100 Tbit/in2. © 2013 AIP Publishing LLC.

Strohmeier D.,Upper Austria University of Applied Sciences
New directions for youth development | Year: 2012

The ViSC Social Competence Program has been implemented in Austrian schools within the scope of a national strategy plan, Together Against Violence. The program is a primary preventive program designed for grades 5 to 8. The prevention of aggression and bullying is defined as a school development task, and the initial implementation of the program lasts one school year. The program consists of universal and specific actions that are implemented through in-school teacher training and a class project for students. The program was evaluated with a randomized intervention control group design. Data were collected from teachers and students. Results suggest that the program reduces aggression in schools. Copyright © 2012 Wiley Periodicals, Inc., A Wiley Company.

Lawlor V.,Upper Austria University of Applied Sciences
Journal of Power Sources | Year: 2013

Micro-Tubular Solid Oxide Fuel Cells (MT-SOFCs) are small tubular shaped, ceramic based, electrochemical electrical power generation devices that operate at high temperatures and can potentially be fuelled with hydrocarbon based fuels. In comparison to Part I of this review paper series, which considered stacks of MT-SOFCs, part II aims to gather and arrange information regarding MT-SOFCs, in order provide a state of the art account for those entering the field or those interested in the technology. This review paper deals with MT-SOFC; reported architectures, geometry and cost considerations, details regarding individual cell components, reported methods of producing MT-SOFCs, reports and details regarding MT-SOFCs and reforming, reported novel modes of operation, reports regarding the mechanical properties of MT-SOFCs, comment and reports regarding SOFC/MT-SOFC reliability and durability, and finally, comment and conclusions. © 2013 Elsevier B.V. All rights reserved.

Lanzerstorfer C.,Upper Austria University of Applied Sciences
Advances in Cement Research | Year: 2016

In cement plants, large amounts of dust are generated and these have to be separated from various off-gases before discharge. The physical and flow properties of these dusts are important for the design and operation of the dust separation process and handling and storage facilities. In this study, five cement kiln dusts and three dusts from other sources in cement production were investigated. Shear tests showed that the flowability of most dust is very poor. Furthermore, the flowability depends on the consolidation stress: the higher the consolidation stress, the better the flowability. Three flowability indicators - the angle of repose, the Hausner ratio and Carr's compressibility - were also determined, but these indicators produced very inconsistent results. In most cases, the flowability of the dust was overestimated. Therefore, shear tests are strongly recommended for reliable categorisation of the flowability of dusts from cement plants.

Dreiseitl S.,Upper Austria University of Applied Sciences
AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium | Year: 2012

The accurate assessment of the calibration of classification models is severely limited by the fact that there is no easily available gold standard against which to compare a model's outputs. The usual procedures group expected and observed probabilities, and then perform a χ(2) goodness-of-fit test. We propose an entirely new approach to calibration testing that can be derived directly from the first principles of statistical hypothesis testing. The null hypothesis is that the model outputs are correct, i.e., that they are good estimates of the true unknown class membership probabilities. Our test calculates a p-value by checking how (im)probable the observed class labels are under the null hypothesis. We demonstrate by experiments that our proposed test performs comparable to, and sometimes even better than, the Hosmer-Lemeshow goodness-of-fit test, the de facto standard in calibration assessment.

Roland M.,Upper Austria University of Applied Sciences
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST | Year: 2014

The ecosystem behind secure elements is complex and prevents average developers from creating secure element applications. In this paper we introduce concepts to overcome these issues. We develop two scenarios for open platforms emulating a secure element for the Android platform. Such an open emulator can be used for debugging and rapid prototyping of secure element applications. Moreover, by trading the secure element’s security and trust for openness, such a platform can be used as a replacement for the secure element for long-term testing and for showcasing of applications. © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2014.

Strohmeier D.,Upper Austria University of Applied Sciences
New directions for youth development | Year: 2012

This chapter reviews recent research on bullying from an educator's perspective. It is well known that bullying, a serious issue in schools, can be prevented when educators intervene. But research has shown that it is difficult for educators to detect bullying situations in their school and intervene competently and effectively. This chapter examines how educators can detect bullying, how they can best tackle serious cases of bullying, and how they can best prevent bullying in the long run. Copyright © 2012 Wiley Periodicals, Inc., A Wiley Company.

Lawlor V.,Upper Austria University of Applied Sciences
Journal of Fuel Cell Science and Technology | Year: 2012

Within the following brief is the researched conclusion that there is a lack of fundamental experimental data available to the scientific community detailing the temperature profile through the cathode/electrolyte/anode assembly section of Solid Oxide Fuel Cells (SOFC). Within these electrochemical reaction driving deceives, heat may be generated and diminished by several means. For example, heat is generally considered to be generated locally; as a result of the reactor's fundamental operation. Furthermore, heat is generally considered to be generated and/or diminished, depending on the reforming method used, when the anode executes hydrocarbon fuel reformation. Not continually developing and/or utilizing novel experimental techniques, often developed for other fields, in order to provide fundamentally elucidating experimental data regarding SOFC operation is counter-intuitive. To date, the high temperature fuel cell field has not fully adopted the potential of thermography in order to study SOFC internal operation and indeed material characterization. This may be caused by the recent rapid development of the technology, which has reduced its cost while increasing its scope. This technical brief aims to highlight missing experimental data and suggest a technology and approach that may be able to address the issue. © 2012 American Society of Mechanical Engineers.

The focus of the present article lies on new enhanced beam finite element formulations in the absolute nodal coordinate formulation (ANCF) and its embedding in the available formulations in the literature. The ANCF has been developed in the past for the modeling of large deformations in multibody dynamics problems. In contrast to the classical nonlinear beam finite elements in literature, the ANCF does not use rotational degrees of freedom, but slope vectors for the parameterization of the orientation of the cross section. This leads to several advantages compared to the classical formulations, e.g. ANCF elements do not necessarily suffer from singularities emerging from the parameterization of rotations. In the classical large rotation vector formulation, the mass matrix is not constant with respect to the generalized coordinates. In the case of ANCF elements, a constant mass matrix follows, which is advantageous in dynamic analysis. In the standard geometrically exact formulation, the parameterization of rotations leads to a nonlinear term containing quadratic velocities. The so-called quadratic velocity vector vanishes for ANCF elements which is advantageous in dynamic applications. In the present article, existing beam finite element formulations are analyzed and improved to derive formulations which are able to solve industrial applications with high performance, efficiency and accuracy. The interest lies especially on finite element formulations for multibody dynamics systems that are capable of large deformations in order to derive accurate solutions of nonlinear engineering and research problems. Existing shear deformable ANCF beam finite elements show an overly stiff behavior caused by the locking phenomenon. Existing locking problems are discussed in this article and avoided in the proposed elements in order to gain accurate solutions. The state of the art of ANCF elements in literature is reviewed including the basic description of the kinematics, interpolation strategies and definition of elastic forces, but also problems and known disadvantages arising in the existing elements, as e.g. the locking phenomenon. Regarding the description of the elastic forces, the present article shows the two standard approaches in literature as well as new enhanced formulations to avoid locking: a continuum mechanics based formulation for the elastic forces with elimination of Poisson and shear locking, and an extended hybrid structural mechanics based formulation for the elastic forces including a term for penalizing shear and cross section deformation. The definition of the element kinematics and interpolation strategies in existing elements are discussed and compared to the according descriptions of the proposed elements. A comparison of the solution of the proposed finite elements to analytical solutions in the literature and to the solution retrieved from commercial finite element software have shown high accuracy and high order of convergence. The speed of convergence is evaluated regarding different interpolation strategies and different formulations for the elastic forces. The investigations show that the proposed elements have high potential for simulation of geometrically nonlinear problems arising from real-life multibody applications and therefore are highly competitive with existing elements in commercial finite element codes. It has to be mentioned here that most of the studies on nonlinear elements based on the ANCF in literature use linear constitutive laws. Regarding many applications in which geometric and material nonlinearities arise, elastic material models are not sufficient to represent the real problem accurately. For this reason, an extension of the material model is necessary in order to fulfill the requirements of current but also of future materials arising in engineering or research. An overview of existing nonlinear material models in literature can be found in the "Appendix". © 2014 CIMNE, Barcelona, Spain.

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