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Abstract
Sensory processing sensitivity (SPS) is a personality trait characterized by a high sensitivity to sensory stimuli (Aron & Aron, 1997). On the basis of environmental sensitivity theory (Pluess & Boniwell, 2015) as well as the job characteristics model (Hackman & Oldham, 1976), we investigated the moderating impact of SPS (HSP Scale; Aron & Aron, 1997; Konrad & Herzberg, 2019) on the relationship between job characteristics (Work Design Questionnaire; Morgeson & Humphrey, 2006; Stegmann et al., 2010) and organizational citizenship behavior (OCB Scale; Podsakoff et al., 1990). The results of our two-wave survey study with 199 employees from a broad range of industries and students indicate that SPS strengthens the relationship between feedback as well as task significance and OCB, but SPS weakens the relationship between autonomy (work methods) as well as task variety and OCB.
Fake News, PR-Skandal, Mainstream-Presse – diese Schlagworte kennzeichnen vor allem eines: den Vertrauensverlust der Öffentlichkeit in die Berichterstattung von Medien und Unternehmen. In einem nahezu unentwirrbaren Kommunikationsdschungel aus Medien, Internetportalen und sozialen Plattformen wird es nicht nur für Laien immer schwieriger, verlässliche und unseriöse Kommunikation voneinander zu unterscheiden.
So steigt die Anzahl derer, die professioneller Kommunikation mit Misstrauen begegnen und in ihr vor allem Einflussnahme oder gar Manipulation sehen. Aus den Augen gerät dabei oft, dass Deutschland über eines der freiheitlichsten und vielfältigsten Mediensysteme der Welt verfügt.
Das Buch diskutiert die Grenzen zwischen Manipulation und Kommunikation on- wie offline und zeigt, wie man schlampige und seriöse Meinungsmacher unterscheidet, welche Rolle Fakten spielen und wie Medien und Unternehmen dazu beitragen können, dass Glaubwürdigkeit in der medialen Debatte wieder einen Stellenwert bekommt.
Abstract
Earthquakes, fire, and floods often cause structural collapses of buildings. However, the inspection of such damaged buildings poses a high risk for emergency forces or is even impossible. We present three recently selected missions of the Robotics Task Force of the German Rescue Robotics Center (DRZ), where both ground and aerial robots were used to explore destroyed buildings. We describe and reflect the missions as well as the lessons learned that have resulted from them. To make robots from research laboratories fit for real operations, realistic outdoor and indoor test environments were set up at the DRZ and used for tests in regular exercises by researchers and emergency forces. On the basis of this experience, the robots and their control software were significantly improved. Furthermore, expert teams of
researchers and first responders were formed, each with realistic assessments of the operational and practical suitability of robotic systems.
Integrity Assessment of Electron-Beam-Welded Joints of Additively Manufactured AlSi10Mg Components
(2023)
Abstract
Laser-based powder bed fusion of metals (PBF-LB/M) is found to be a promising
processing method for the fabrication of components with no limits of complexity
by adding layers upon layers of material. However, drawbacks such as pro-
ductivity and dimension limitations adversely affect the employment of com-
ponents processed by additive manufacturing (AM) in envisaged applications.
This brings welding and joining techniques into play to integrate AM metal parts
into larger assemblies. In the present study, electron beam welding is used to join
the AlSi10Mg specimens, fabricated via two different manufacturing processes,
that is, PBF-LB/M and casting. The main focus is to study the quasistatic and
fatigue behavior of similar and dissimilar welded joints in different combinations,
namely AM–AM, AM–cast, and cast–cast, alongside thorough microstructure
analysis, to investigate the correlation between the microscopic and macroscopic
properties. Dissimilar welded joints demonstrate inferior material strength. This
fact can be attributed to the inherent coarse microstructure of the cast material.
Although similar welded joints of AM components suffer from high porosity in
the weld zone, they are characterized by a better fatigue life, which can be
attributed to the equiaxed eutectic microstructure in the welded area.
Diese Arbeit bietet einen Überblick über das Thema der ereignisbasierten Systemüberwachung von Windows-PCs. Die frühe Erkennung von Angriffen und der Ausführung von Schadsoftware auf Windows-Clients bedingt Sensor-Technologien, die Systemereignisse erkennen und protokollieren. Anhand bestimmter Ereignisse oder komplexerer Ereignismuster können illegitime Vorgänge auf Computersystemen erkannt werden. Der Fokus dieser Arbeit liegt darauf einen detaillierten Überblick über diese ereignisbasierte Sensorik für Windows-Endpunkte zu geben, die Systemereignisse erkennt und Ereignis-Objekte mit beschreibenden Attributen liefert. Im Gegensatz dazu wird die Interpretation der bereitgestellten Ereignisdaten und der Musterabgleich in dieser Arbeit nicht behandelt. Zu Beginn werden dafür die elementaren Aspekte und Begriffe einer solchen Sensor-Technologie allgemein erklärt. Dabei werden einige charakterisierende Grundeigenschaften erläutert, anhand derer solche Senor-Verfahren eingeordnet werden können. Zudem wird auf Basis durchgeführter Messungen eine Abschätzung bezüglich der Auftrittsfrequenzen verschiedener Systemereignisse geliefert. Im Hauptteil werden die zwei ereignisbasierten Monitoring-Systeme Event-Tracing-for-Windows (ETW) und Sysmon vorgestellt. Die Funktionalität, Architektur und interne Funktionsweise der beiden Systeme wird detailliert erläutert. Zudem werden ihre charakterisierenden Basiseigenschaften herausgearbeitet, um Stärken und Schwächen zu erkennen. Der ETW-basierte Sensor und SIGMA-Regelscanner Nextron Aurora, der Sysmon-ähnliche Ereignisdaten bereitstellt, wird ebenfalls behandelt.
Um grünen Wasserstoff effizient als Energieträger nutzen zu können, ist die Entwicklung von haltbaren und aktiven Katalysatorschichten für Brennstoffzellen und Elektrolyseuren von äußerster Wichtigkeit. Eine große Herausforderung ist, dass konventionelle C/Pt-Katalysatoren eine starke Korrosionsreaktion durchlaufen und mit hohen Kosten verknüpft sind. Weswegen alternative Kohlenstoffträger wie Kohlenstoffnanofaser-Materialien entwickelt wurden, welche eine längere Haltbarkeit aufweisen können. In dieser Arbeit wurde die Aufbringung von Pt- und Ir-Nanopartikeln auf gesponnene Kohlenstoffnanofaser-Vliese untersucht. Es wurden erstmals in einer Flüssigkeit laserablatierte Pt-Nanoartikel mit einem PAN-Vlies versponnen oder in einem zweiten Syntheseverfahren auf ein Vlies aufgesprüht. Diese Methoden wurden mit der gepulsten galvanischen Abscheidung von Pt auf einem PAN-Vlies verglichen. Die Vliese wurden bezüglich ihres Graphitisierungsgrades, ihrer Partikelverteilung und ihrer Beständigkeit untersucht, einschließlich des Einflusses der Karbonisierungstemperatur. Die Raman- und XRF-Messungen ergaben eine Erhöhung des Graphitisierungsgrades und eine Abnahme der PAN-Reste mit dem Anstieg der Karbonisierungstemperatur. Elektrochemische Messungen und REM-Aufnahmen bestätigten die erfolgreiche Synthese von langzeitstabilen CNF-Vliesen mit einer hohen massenspezifischen aktiven Platinoberfläche und einer guten Nanopartikelverteilung. Diese Ergebnisse tragen zur Entwicklung von ökologischen und ökonomischen Katalysatorschichten bei.
Ni-based alloys are among the materials of choice in developing high-quality coatings for ambient and high temperature applications that require protection against intense wear and corrosion. The current study aims to develop and characterize NiCrBSi coatings with high wear resistance and improved adhesion to the substrate. Starting with nickel-based feedstock powders, thermally sprayed coatings were initially fabricated. Prior to deposition, the powders were characterized in terms of microstructure, particle size, chemical composition, flowability, and density. For comparison, three types of powders with different chemical compositions and characteristics were deposited onto a 1.7227 tempered steel substrate using oxyacetylene flame spraying, and subsequently, the coatings were inductively remelted. Ball-on-disc sliding wear testing was chosen to investigate the tribological properties of both the as-sprayed and induction-remelted coatings. The results reveal that, in the case of as-sprayed coatings, the main wear mechanisms were abrasive, independent of powder chemical composition, and correlated with intense wear losses due to the poor intersplat cohesion typical of flame-sprayed coatings. The remelting treatment improved the performance of the coatings in terms of wear compared to that of the as-sprayed ones, and the density and lower porosity achieved during the induction post-treatment had a significant positive role in this behavior.
Without proper post-processing (often using flame, furnace, laser remelting, and induction) or reinforcements’ addition, Ni-based flame-sprayed coatings generally manifest moderate adhesion to the substrate, high porosity, unmelted particles, undesirable oxides, or weak wear resistance and mechanical properties. The current research aimed to investigate the addition of ZrO2 as reinforcement to the self-fluxing alloy coatings. Mechanically mixed NiCrBSi-ZrO2 powders were thermally sprayed onto an industrially relevant high-grade steel. After thermal spraying, the samples were differently post-processed with a flame gun and with a vacuum furnace, respectively. Scanning electron microscopy showed a porosity reduction for the vacuum-heat-treated samples compared to that of the flame-post-processed ones. X-ray diffraction measurements showed differences in the main peaks of the patterns for the thermal processed samples compared to the as-sprayed ones, these having a direct influence on the mechanical behavior of the coatings. Although a slight microhardness decrease was observed in the case of vacuum-remelted samples, the overall low porosity and the phase differences helped the coating to perform better during wear-resistance testing, realized using a ball-on-disk arrangement, compared to the as-sprayed reference samples.
Among the FDM process variables, one of the less addressed in previous research is the filament color. Moreover, if not explicitly targeted, the filament color is usually not even mentioned.
Aiming to point out if, and to what extent, the color of the PLA filaments influences the dimensional precision and the mechanical strength of FDM prints, the authors of the present research carried out experiments on tensile specimens. The variable parameters were the layer height (0.05 mm, 0.10 mm, 0.15 mm, 0.20 mm) and the material color (natural, black, red, grey). The experimental results clearly showed that the filament color is an influential factor for the dimensional accuracy as well as for the tensile strength of the FDM printed PLA parts. Moreover, the two way ANOVA test performed revealed that the strongest effect on the tensile strength was exerted by the PLA color (2 = 97.3%), followed by the layer height (2 = 85.5%) and the interaction between the PLA color and the layer height (2 = 80.0%). Under the same printing conditions, the best dimensional accuracy was ensured by the black PLA (0.17% width deviations, respectively 5.48% height deviations), whilst the grey PLA showed the highest ultimate tensile strength values (between 57.10 MPa and 59.82 MPa).
Among all additive manufacturing processes, Directed Energy Deposition-Arc (DED-Arc) shows significantly shorter production times and is particularly suitable for large-volume components of simple to medium complexity. To exploit the full potential of this process, the microstructural, mechanical and corrosion behavior have to be studied. High stickout distances lead to a large offset, which leads to an instable electric arc and thus defects such as lack of fusion. Since corrosion preferentially occurs at such defects, the main objective of this work is to investigate the influence of the stickout distance on the corrosion
behavior and microstructure of stainless steel manufactured by DED-Arc.
Within the heterogenous structure of the manufactured samples lack of fusion defects were detected. The quantity of such defects was reduced by applying a shorter stickout distance. The corrosion behavior of the additively manufactured specimens was investigated by means of potentiodynamic polarization measurements. The semi-logarithmic current density potential curves showed a similar course and thus similar corrosion resistance like that of the conventionally forged sample. The polarization curve of the reference material shows numerous current peaks, both in the anodic and cathodic regions. This metastable behavior is induced by the presence of manganese sulfides. On the sample surface a local attack by pitting corrosion was identified.
