The seed of goal-related doubts : a longitudinal investigation of the roles of failure and expectation of success among police trainee applicants

Various theories on personal goal striving rely on the assumption that failure raises doubts about the goal. Yet, empirical evidence for an association between objective failure experiences and doubts about personal long-term goals is still missing. In a longitudinal field study, applicants for a job as a police trainee (n = 172, Mage = 25.15; 55 females and 117 males) were accompanied across three measurement times over a period of five months. We investigated the effects of failure and initial expectation of success (in the standardized selection process) on doubts regarding the superordinate goal of becoming a police officer. As hypothesized, both failure and low initial expectation of success as well as their interaction led to increased goal-related doubts over time. The findings provide first empirical evidence for the role of failure in the emergence of goal-related doubts in personal long-term goals and, therefore, the disengagement process as it is hypothesized in various theories on goal striving and life-span development

Mikrostrukturierung von Metallen und Wide Band Gap Materialien mit ultrakurzen Laserpulsen

Im Rahmen der Bachelorarbeit wurden Strukturierungsexperimente an verschiedenen Materialien mittels ultrakurzen Laserpulsen durchgeführt. Die untersuchten Materialien sind Stahl (Thyrodur 2990), Wolframcarbid, Quarzglas und PMMA. Die Versuche wurden mit der Laseranlage FS-150-10 durchgeführt. Ziel der Versuche war es Erkenntnisse über das Ablationsverhalten der untersuchten Materialien bei einer Pulsdauer von ca. 35 fs zu gewinnen. Diese Ergebnisse sollten mit denen für 150 fs verglichen werden um den Einfluss der Pulsdauer zu charakterisieren. Desweiteren sollten Einflussfaktoren, welche sich auf die Oberflächenrauheit auswirken untersucht werden. Dazu wurden Testfelder erzeugt und auf ihre Strukturtiefe und Oberflächenrauheit der strukturierten Bereiche untersucht

Vom Indent zum Scratch – Nanomechanische Tests

Da Bauteile immer kleiner und Beschichtungen immer dünner werden, erlangt die direkte und genaue Bestimmung mechanischer Eigenschaften im Nanobereich immer größere Bedeutung. Versteht man die Effekte im Nanobereich, wird es einfacher, auch Effekte im Makrobereich vorherzusagen. Damit bekommen die entsprechenden Messmethoden eine entscheidende Bedeutung bei der Entwicklung der Materialien und Herstellungsmethoden im Hinblick auf optimierte Produkteigenschaften. Aus diesem Grund entwickelte sich jenseits der klassischen mechanischen Prüfverfahren, welche in der Makrodimension angesiedelt sind, in den letzten fünf Jahren ein neuer Zweig der Werkstoffprüfung, der sich mit den Materialeigenschaften im Nanobereich beschäftigt. Dies ist von grundlegender Bedeutung für die Nanotechnologie. In diesem Bericht sollen zwei Geräte in Bezug zueinander gesetzt werden, die die Messung verschiedener nanomechanischer Eigenschaften erlauben. Dabei handelt es sich um das TriboScope (Hysitron Inc.) als Aufsatz für ein Rasterkraftmikroskop (SFM) und das Nanoscan (Technological Institute for Superhard and Novel Carbon Materials; Troitsk/Russland), dargestellt in den Abbildungen 1 und 2. Diese ermöglichen die Messung von Härte und E-Modul einer Oberfläche

Identification, simulation and optimal control of heat transfer in cooling line of hot strip rolling mill

The numerical simulation of mechanical properties of hot-rolled products has a major significance for material characterisation as well as material development. The basis for these is the knowledge about the material-specific phase transformations in combination with the initial microstructure from the deformation steps before entering into the cooling line. Additionally, the technological conditions in the run-out table (ROT) are essentially for transformation kinetics. In order to simulate these processes, the plant-specific heat transfer coefficient must be measured. Therefore, steel samples with thermocouples inside are transported with defined velocities through the cooling line of the continuous pilot plant at the Institute of Metal Forming in Freiberg. Furthermore, the material and its movement must be taken into account as characteristics of the ROT (e.g. amount and distribution of the cooling medium, the streaming situation in several segments, the nozzle geometry and, as a consequence, the water jet shape, and the impact pressure of the cooling medium on the surface of the rolled material) as influencing parameters. This paper describes the possibilities for determining and simulating the heat transfer in the cooling line with industrial conditions. Moreover, this paper discusses the optimal control of the cooling line to achieve the desired temperature and phase distribution on the run-out table. The resulting information contributes to new technology and material developments at the pilot plant, as well as for the transfer of results into the industry

Engineering human cell-based, functionally integrated osteochondral grafts by biological bonding of engineered cartilage tissues to bony scaffolds

In this study, we aimed at developing and validating a technique for the engineering of osteochondral grafts based on the biological bonding of a chondral layer with a bony scaffold by cell-laid extracellular matrix. Osteochondral composites were generated by combining collagen-based matrices (Chondro-Gide) containing human chondrocytes with devitalized spongiosa cylinders (Tutobone) using a fibrin gel (Tisseel). We demonstrate that separate pre-culture of the chondral layer for 3 days prior to the generation of the composite allows for (i) more efficient cartilaginous matrix accumulation than no pre-culture, as assessed histologically and biochemically, and (ii) superior biological bonding to the bony scaffold than 14 days of pre-culture, as assessed using a peel-off mechanical test, developed to measure integration of bilayered materials. The presence of the bony scaffold induced an upregulation in the infiltrated cells of the osteoblast-related gene bone sialoprotein, indicative of the establishment of a gradient of cell phenotypes, but did not affect per se the quality of the cartilaginous matrix in the chondral layer. The described strategy to generate osteochondral plugs is simple to be implemented and--since it is based on clinically compliant cells and materials--is amenable to be readily tested in the clinic

How self-awareness is connected to less experience of action crises in personal goal pursuit

In this research, we applied a differential perspective to the study of action crises, i.e., being in an intra-psychic decisional conflict whether to pursue or abandon a goal once difficulties in its pursuit arise. In two studies, we investigated the role of individuals’ levels of self-awareness when experiencing such action crises. Both among professional ballet dancers (daily diary, Study 1) and university undergraduates (preregistered experience sampling, Study 2), individuals with greater levels of (dispositional and situational) self-awareness showed an adaptive, that is, problem-solving oriented way of dealing with difficulties in the pursuit of their (training or study) goals. As a consequence, self-awareness contributed to less experience of action crisis during goal pursuit and, as a result, led to better goal performance

Tunable sub-20 fs pulses from a 500 kHz OPCPA with 15 W average power based on an all-ytterbium laser

An optical parametric chirped pulse amplifier fully based on Yb lasers at 500 kHz is described. Passive optical-synchronization is achieved between a fiber laser-pumped white-light and a 515 nm pump produced with a 200 W picosecond Yb:YAG InnoSlab amplifier. An output power up to 19.7 W with long-term stability of 0.3% is demonstrated for wavelength tunable pulses between 680 nm and 900 nm and spectral stability of 0.2%; 16.5 W can be achieved with a bandwidth supporting 5.4 fs pulses. We demonstrate compression of 30 microjoule pulses to sub-20 fs duration with a prism compressor, suitable for high harmonic generation.Comment: 4 pages, 4 figure

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