Detecting Potential Neurotoxic Pseudo-nitzchia Species in the Grand Strand

Pseudo-nitzschia is a globally distributed diatom genus which contains 26 neurotoxin (domoic-acid) producing species. In shallow coastal waters these diatoms are associated with both the development of harmful algal blooms and the bioaccumulation of toxins in shellfish that can impact human health. Environmental DNA (eDNA) samples drawn from the public shellfish harvesting area at Huntington Beach State Park (SC) during the summer of 2021 were PCR- screened for Pseudo-nitzschia species using genus specific primers. The sequences of the recovered amplicons are used to molecularly characterize the species of Pseudo-nitzschia present and their potential to produce domoic acid

Auslegung und Berechnung von kurzglasfaserverstärkten Kunststoffbauteilen in Lenksystemen

Short glass fiber-reinforced plastic (sfrp) parts are increasingly used as structural parts bearing mechanical loads in passenger car steering systems and thus subjected to quasistatic loads as well as a large number of load cycles. The design of these parts is frequently based on isotropic, linear elastic, numeric calculations, although it is possible to take into account the nonlinear, elastoplastic and anisotropic material behavior for calculations of sfrp parts. This fact results in potential improvements regarding product development, which are shown in this work. In addition, these improvements are part of the product development process of sfrp parts in passenger car steering systems. Different models for the description of quasistatic mechanical material behavior will be compared within this document. Calculation results used for modelling the deformation are rated. Regarding cyclic stress on sfrp within steering systems, a prediction for lifetime is introduced as a strain-based design concept. This concept will enable a more exact prediction than the one currently used for the design of parts. Besides the calculation enhancement for sfrp materials for steering systems, all parameters having an influence on the mechanical material behavior must be considered. Here, the influences from the manufacturing and operation of the steering system should be taken into account, as well as environmental influences. Influences from parts manufacturing and the usage of steering systems show deviations and therefore have a different effect on the mechanical material behavior. Within this paper, these variations are described and the influence on quasistatic, as well as cyclic, mechanical material behavior, is explored. The goal of this investigation is to reach a reliable prediction of loading and durability of sfrp materials.Kurzglasfaserverstärkte (kgfv) Kunststoffbauteile werden zunehmend häufig im Kraftfluss von Pkw-Lenksystemen verbaut. Dabei sind die Bauteile sowohl hohen quasistatischen Lasten als auch einer Vielzahl von niedrigen, sich zyklisch wiederholenden Belastungen ausgesetzt. Die Auslegung dieser Bauteile findet auf Basis von isotropen, linearelastischen numerischen Berechnungen statt, obwohl heutzutage das nichtlineare, elastoplastische und anisotrope Werkstoffverhalten von kgfv Kunststoffen in der Simulation berücksichtigt werden kann. Daraus ergeben sich Potentiale insbesondere für Verbesserungen bei der Produktentwicklung, welche diese Arbeit aufzeigt. Zudem werden diese Verbesserungen in den Produktentstehungsprozess von Lenkungsbauteilen aus kgfv Kunststoff integriert. In einer Gegenüberstellung unterschiedlicher Modelle zur Beschreibung des quasistatischen, mechanischen Werkstoffverhaltens von kgfv Kunstoffen findet in dieser Arbeit ein Vergleich und eine Bewertung der Berechnungsergebnisse hinsichtlich der Abbildung der Beanspruchung und der Beanspruchbarkeit statt. Zur Vorhersage der Lebensdauer der kgfv Kunststoffbauteile unter zyklischer Belastung in Lenksystemen wird ein dehnungsbasierter Ansatz vorgestellt. Dieser soll eine genauere Prognose als die momentane Auslegung der Bauteile ermöglichen. Neben der Verbesserung der Berechnung des Verhaltens von kgfv Kunststoffen in Pkw-Lenksystemen müssen Einflussgrößen berücksichtigt werden, die Auswirkungen auf das mechanische Werkstoffverhalten haben. Hier sind vor allem Einflüsse aus der Herstellung, dem Betrieb des Lenksystems sowie die Umwelteinflüsse zu nennen. Die Einflüsse aus der Herstellung der Bauteile und dem Betrieb des Lenksystems unterliegen Streuungen und wirken sich dadurch unterschiedlich stark auf das mechanische Werkstoffverhalten aus. Die vorliegende Arbeit beschreibt diese Streuungen und analysiert ihren Einfluss sowohl auf das quasistatische als auch auf das zyklische, mechanische Werkstoffverhalten. Das Ziel dieser Untersuchung ist es, eine zuverlässige Vorhersage der Belastung, der Beanspruchung und Beanspruchbarkeit von kgfv Kunststoffen treffen zu können

Analysis of the Association Between Topics in Online Documents and Stock Price Movements

This paper aims at discovering the topics hidden in the newspaper articles that have an impact on movements of stock prices of the corresponding companies. Document topics are characterized by combinations of specific words in documents and are shared across a document collection. We describe the process of discovering the topics, the creation of a mapping of the topics to stock price movements, and quantifying and evaluating the results. As the method for finding and quantifying the association, we use machine learning-based classification. We achieved an accuracy of stock price movement predictions higher than 70 %. A feature selection procedure was applied to the features characterizing the topics in order to facilitate the process of assigning a label to the topic by a human expert.O

Dark Matter and the Chemical Evolution of Irregular Galaxies

We present three types of chemical evolution models for irregular galaxies: closed-box with continuous star formation rates (SFRs), closed-box with bursting SFRs, and O-rich outflow with continuous SFRs. We discuss the chemical evolution of the irregular galaxies NGC 1560 and II Zw 33, and a ``typical'' irregular galaxy. The fraction of low-mass stars needed by our models is larger than that derived for the solar vicinity, but similar to that found in globular clusters. For our typical irregular galaxy we need a mass fraction of about 40% in the form of substellar objects plus non baryonic dark matter inside the Holmberg radius, in good agreement with the results derived for NGC 1560 and II Zw 33 where we do have an independent estimate of the mass fraction in non baryonic dark matter. Closed-box models are better than O-rich outflow models in explaining the C/O and Z/O observed values for our typical irregular galaxy.Comment: 14 pages, 2 figure, uses emulateapj.sty package. ApJ in press. New models were added. The order of Tables has been correcte

Process-Structure Coupled Simulation of Additive Manufactured Components

In this work, the influence of extrusion infill angles on the mechanical properties of 3D printed (Fused Filament Fabrication, FFF) test specimens are investigated, considering the real geometry of the components. Therefore, various polylactide (PLA) specimens with different infill angles are manufactured, scanned by Computed Tomography (CT) and further investigated by mechanical testing using an optical measuring system. This allows the directional dependence and the elastoplastic behavior of the material to be demonstrated. It was found that the real geometry behavior differs significantly from the model. In addition to the tests Finite Element Method (FEM) simulations of the scanned components are carried out in order to provide a prediction of the mechanical properties of FFF-printed parts for component manufacturers. The conducted simulations have shown that the geometric deviation leads to an increase in stiffness, a higher ultimate tensile strength and strain at failure. The main objective of this work is to evaluate the stiffness and strength of FFF-printed components using FEM with an economically justifiable testing effort. This includes not only the evaluation of the directional dependence, considering the real geometry of the components, but also the evaluation of a suitable strength criterion. The criterion of maximum principal strain has proved to be suitable