Ostwestfalen-Lippe University of Applied Sciences and Arts
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Comparison of different statistical methods for prediction of lifetime of electrical connectors with short term tests
No full textLifetime is an important feature defining the reliability of electrical connectors. In general practice, the lifetime tests required for reliability estimation are time and labor intensive. In our previous work, a data driven method using a statistical process, with an application of probability distributions such as standard normal distribution and generalized extreme value (GEV) distribution with negative skewness to predict degradation paths, was introduced for estimation of the lifetime and FIT rate with the help of electrical contact resistance data collected from short term tests. The proposed method proved its significance by showing the possibility of drastic reduction in the lifetime test duration required for reliability determination. In this work, a non-parametric distribution free method using percentiles of actual measured contact resistances is used for determining the lifetime as against the percentiles of probability distribution used in previous work, thereby simplifying the process further and leading to an even more precise estimation. The lifetimes calculated from parametric and non-parametric methods are compared to highlight the significance of distribution free method in reliability estimation
Advances in Evaluation of State of Health of Electrical Connectors
No full textThe state of health and lifetime estimation process of electrical connectors via lifetime tests is a time and labor intensive process. In our previous work, a correlation between the contact resistance developments in the early stages of lifetime tests of electrical connectors with the final results was established using a data driven statistical process based on probability distribution. Also, state of health indicators for prognosis of lifetime were introduced. In this work, the state of health indicators have been optimized. The sensitivity analysis is performed with regards to the selection of the appropriate amount of test data based on test duration for the reliable prognosis of the state of health and the characteristic lifetime. Through this the possibility of further reduction of test duration required for the reliable prognosis of state of health is investigated. Based on the results of analysis, a guideline for the determination of the duration of lifetime tests which lead to a reliable prediction of lifetime of connectors can be provided. Also, an assessment of the state of art in the prognosis of the lifetime of electrical connectors has been presented
Validation and Uncertainty Assessment of a Software‐Integrated Workflow for pH Calculations
No full textAccurate pH calculations are essential for scientists across different disciplines to design optimal reactor solutions, but they can be arduous to calculate for complex acid-base solutions. Visual Water is a powerful software tool that provides accurate pH calculations with automated mathematical uncertainty analysis. Its workflow is presented and validated using acids and bases, showing a deviation of < 0.2 pH units between measured and calculated pH values. This highlights the software's reliability, which can help to simplify the work of non-experts in water chemistry
Comparison of Preprocessing Methods of Dielectric Spectroscopy Data and the Effects on Linear Regression
No full textSame same but different? Integration of collective orientation(s) and their relationship with performance
No full textOrganizational and research interest in collective orientation, an individual’s orientation towards groups, has been growing over the past decades. Yet, collective orientation remains a blurry concept. Integrating latent semantic analysis and meta-analyses, we systematize and compare conceptualizations and measures and thereby evaluate its importance for predicting individual and team performance
Hybride Prozessgestaltung im Innovet-Projekt Bildungsbrücken OWL
Get PDFDas Verbundprojekt Bildungsbrücken OWL (BB OWL) ist Teil des InnoVET-Programms des Bundesministeriums für Bildung und Forschung (BMBF) für eine exzellente berufliche Bildung. Über definierte Themencluster verfolgt InnoVET die Ziele Attraktivität, Qualität und Gleichwertigkeit der beruflichen Bildung zu steigern und neue Lernortkooperationen zu initiieren (BMBF, 2021). Die Gestaltung von Kooperationen ist im Projekt jedoch nicht nur Zielsetzung, vielmehr ist Kooperation und Hybridität von beruflicher und akademischer Bildung zur „DNA“ des gesamten Projektvorgehens geworden. Das Projekt BB OWL ist getragen von einer starken regionalen Verantwortungsgemeinschaft, die in einem abgestimmten Prozess gemeinsame Bildungsformate bzw. gemeinsame Lernorte entwickelt und flexible Bildungswege ermöglicht. Im Projekt arbeiten vier Partner gleichwertig zusammen: Die TH OWL für die akademische Bildung, der Eigenbetrieb Schulen des Kreises Lippe für die schulisch-berufliche Bildung, die Kreishandwerkerschaft Paderborn-Lippe für die gewerblich-berufliche Bildung und die Lippe Bildung eG als regionales Bildungsnetzwerk. Die Arbeit im Projekt ist durchgängig kooperativ angelegt, d. h. sowohl in allen Arbeitsgruppen der inhaltlichen Teilprojekte als auch im Projektmanagement arbeiten Personen aus allen Projektpartnern zusammen und bringen die jeweilige Perspektive ein (Abbildung 1). Dadurch ist ein Zusammenwirken eigenständiger, komplexer und unterschiedlicher Systeme des beruflichen und akademischen Bildungsbereichs erforderlich, repräsentiert durch die vier Verbundpartner (Hager et al., 2024)
Extension of Biodiesel Aging Mechanism–the Role and Influence of Methyl Oleate and the Contribution of Alcohols Through the Use of Solketal
No full textThe energy crisis and dependence on fossil fuels forces societies to develop alternative pathways to secure energy supplies. Therefore, non‐fossil fuels such as biofuels and e‐fuels can help counteract the resulting demand for existing combustion engines. However, biofuels, like biodiesel, have disadvantages in terms of oxidation stability. In general, aging of biodiesel is a complex mechanism due to interaction of various components. In order to develop an ideal fuel, the mechanism must be understood in full detail. In this work, an attempt is made to simplify the system by using methyl oleate as a biodiesel model component. In addition, other fuel components of interest such as alcohols and their respective acids help to clarify the aging mechanism. This work used isopropylidene glycerol (solketal) as the main alcohol, 1‐octanol and octanoic acid. A holistic biodiesel aging scheme was developed by using generated data and evaluating the role of acids. They epoxidize unsaturated fatty acid via Prileschajev reactions. In addition, the role of epoxides in oligomerization reactions is confirmed. Moreover, the alcohols show that the suppression of oligomerization can be achieved by the reaction with methyl oleate. The alcohol‐dependent aging products were determined by quadrupole time‐of‐flight (Q‐TOF) mass spectrometry
Design of individual simulation games in manufacturing companies for game-based learning
No full textThe digital transformation of manufacturing companies is a huge driver of complexity in organizational structures and processes. Challenges such as an increasing number of variants, rapid changes in technology, and a multitude of interfaces between IT systems within companies require changed qualifications in the workforce. Employees lack a profound understanding of the added value that digitalization can bring to the company and themselves. To address these challenges, simulation games are a suitable approach. Simulation games are active learning methods that simulate real systems in an artificial environment. The goal is to give employees the opportunity to gain experience and make decisions without creating a pressure situation or endangering the real production system. This enables them to better understand, evaluate and design real systems. In order to make optimal use of simulation games in manufacturing companies, they should be customized to the company and its employees due to individual processes and structures. This paper presents a procedure model for designing a concept of individualized simulation games for manufacturing companies in the context of digitalization. It starts with the identification of requirements. Subsequently, the requirements of the individual elements are combined into a holistic simulation game. The piloting of the framework is presented using an example from industrial practice