Offenburg University of Applied Sciences
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Mechanical properties of multi-material polymers additively manufactured with fused layer modeling using a single nozzle
No full textAdditive manufacturing technologies for plastics are typically used in industry for prototypes, presentation models and small batches but also additive tooling. Especially for low volumes, this manufacturing method offers a high degree of efficiency, since no special tools or fixtures are required, which leads to a significant reduction in manufacturing costs and manufacturing time. Up to now, applications have usually been made using only one material, as the use of different materials in a single printing process is a particular challenge. In this contribution, the state of the art for printing processes suitable for multi-material printing and associated application examples are first presented in a literature search. The focus of this contribution is on the fused layer modeling (FLM) process with experiments and analysis on the application of different materials (PLA, PETG, ASA and PC Blend). A 3D-printer with a single nozzle is available for the practical experiments. Due to an additional multi-material device this 3D-printer is capable of processing up to five different materials in one printing process. Colorful presentation models are the first step to gain experience in multi-material printing. The investigation will then be extended to include the combination of different materials. For this purpose, standardized plastic tensile specimens are additively manufactured and subjected to tensile testing in order to analyze material properties. The tensile specimens are manufactured in different patterns and material combinations. This results in measurements that allow a comparison with the initial materials. In addition, the challenges in the printing process, material selection and material arrangement are demonstrated. In order to develop a functional multi-material component, sufficient fusion in the bonding layer between the materials must be ensured
Getting Hold of the Tobamovirus Particle—Why and How? Purification Routes over Time and a New Customizable Approach
Get PDFThis article develops a multi-perspective view on motivations and methods for tobamovirus purification through the ages and presents a novel, efficient, easy-to-use approach that can be well-adapted to different species of native and functionalized virions. We survey the various driving forces prompting researchers to enrich tobamoviruses, from the search for the causative agents of mosaic diseases in plants to their increasing recognition as versatile nanocarriers in biomedical and engineering applications. The best practices and rarely applied options for the serial processing steps required for successful isolation of tobamoviruses are then reviewed. Adaptations for distinct particle species, pitfalls, and ‘forgotten’ or underrepresented technologies are considered as well. The article is topped off with our own development of a method for virion preparation, rooted in historical protocols. It combines selective re-solubilization of polyethylene glycol (PEG) virion raw precipitates with density step gradient centrifugation in biocompatible iodixanol formulations, yielding ready-to-use particle suspensions. This newly established protocol and some considerations for perhaps worthwhile further developments could serve as putative stepping stones towards preparation procedures appropriate for routine practical uses of these multivalent soft-matter nanorods
Editorial: Neuroprosthetics of the Hand: Current Hot Research Topics, Research Trends and Challenges, and Recent Innovations
Get PDFIf you want to buy a new car today, you can expect a flood of digital features and assistance systems that initially make the analog human heart beat faster. But are these developments right? Can we use all the built-in functions usefully and appropriately and operate them safely in increasingly hectic and dangerous everyday traffic
An international analysis of fraud detection in European structural and investment funds
Get PDFThe aim of this paper is to identify indicators at country level that could prove useful in improving the effectiveness of fraud detection in European Structural and Investment Funds. We analyse data for 454 funds, belonging to the period 2014-2020, from the 28 countries that were members of the European Union in 2014. Explanatory results suggest the convenience of tracking funds, especially in countries with higher GDP and higher transparency levels, and the lesser relevance of the number of irregularities for countries with higher GDP and those receiving larger funds. Fraud and fraud detection rates in individual funds vary significantly across states. Federal states, such as the Federal Republic of Germany, are comparatively successful in detecting fraud in EU funds
Cloud Security Information and Event Management Systems: Cost-effectiveness and Extensibility
No full textSecurity Information and Event Management (SIEM) solutions are a foundational piece for infrastructure observability, helping the Security Operations Center monitor changes to a digital infrastructure. SIEMs collect and process massive amounts of log data, and serve as a central interface to find threats and create visualizations from the collected log data. This thesis discusses the different software aspects and features of SIEM solutions. While every SIEM solution is able to fulfill its core function, different ways of implementation lead to other feature additions. The study implements 3 Proof of Concept SIEM setups, and states the advantages and disadvantages experienced in each. This thesis hopes to expose the inner workings and configuration process of different SIEM implementations to help organizations select or reject a solution type based on the resulting or required features
Output Positioning to Derive Maximum Entropy From Physical Unclonable Functions
No full textPhysical unclonable functions (PUFs) are increasingly generating attention in the field of hardware-based security for the Internet of Things (IoT). A PUF, as its name implies, is a physical element with a special and unique inherent characteristic and can act as the security anchor for authentication and cryptographic applications. Keeping in mind that the PUF outputs are prone to change in the presence of noise and environmental variations, it is critical to derive reliable keys from the PUF and to use the maximum entropy at the same time. In this work, the PUF output positioning (POP) method is proposed, which is a novel method for grouping the PUF outputs in order to maximize the extracted entropy. To achieve this, an offset data is introduced as helper data, which is used to relax the constraints considered for the grouping of PUF outputs, and deriving more entropy, while reducing the secret key error bits. To implement the method, the key enrollment and key generation algorithms are presented. Based on a theoretical analysis of the achieved entropy, it is proven that POP can maximize the achieved entropy, while respecting the constraints induced to guarantee the reliability of the secret key. Moreover, a detailed security analysis is presented, which shows the resilience of the method against cyber-security attacks. The findings of this work are evaluated by applying the method on a hybrid printed PUF, where it can be practically shown that the proposed method outperforms other existing group-based PUF key generation methods
From LMS to LXP: Extending Moodle with AI-based Recommendations for Learning
No full textWe propose a Moodle-based LXP (Learning Experience Platform) architecture that extends the classical Moodle LMS (Learning Management System) into LXP. The extension of the Moodle LMS to an LXP is developed to improve the learner’s motivation and to enable personalized learning. The first component in our architecture of the Moodle - based LXP is a recommender component based on Artificial Intelligence (AI). It helps learners by proposing appropriate learning resources based on the content they are currently studying. These recommendations are derived from metadata of the learning resources, such as predefined descriptions, number of views, ratings, and comments on the resources
Preispolitische Entscheidungstatbestände im Kontext der europäischen Gesetzgebung
Get PDFDie Preispolitik beinhaltet Entscheidungstatbestände, die sich auf die Festlegung, Umsetzung und Änderung von Preisen beziehen. Das preispolitische Aktionsfeld eines Unternehmens wird in unterschiedlicher Weise und Intensität durch rechtliche Rahmenbedingungen bestimmt