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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Comparison of calculated and experimental power in maximal lactate-steady state during cycling

Hauser, Thomas, Adam, Jennifer, Schulz, Henry 11 July 2014 (has links)
Background: The purpose of this study was the comparison of the calculated (MLSSC) and experimental power (MLSSE) in maximal lactate steady-state (MLSS) during cycling. Methods: 13 male subjects (24.2 ± 4.76 years, 72.9 ± 6.9 kg, 178.5 ± 5.9 cm, V_O2max: 60.4 ± 8.6 ml min−1 kg−1, V_ Lamax: 0.9 ± 0.19 mmol l-1 s-1) performed a ramp-test for determining the V_O2max and a 15 s sprint-test for measuring the maximal glycolytic rate (V_ Lamax). All tests were performed on a Lode-Cycle-Ergometer. V_O2max and V_ Lamax were used to calculate MLSSC. For the determination of MLSSE several 30 min constant load tests were performed. MLSSE was defined as the highest workload that can be maintained without an increase of blood-lactate-concentration (BLC) of more than 0.05 mmol l−1 min−1 during the last 20 min. Power in following constant-load test was set higher or lower depending on BLC. Results: MLSSE and MLSSC were measured respectively at 217 ± 51 W and 229 ± 47 W, while mean difference was −12 ± 20 W. Orthogonal regression was calculated with r = 0.92 (p < 0.001). Conclusions: The difference of 12 W can be explained by the biological variability of V_O2max and V_ Lamax. The knowledge of both parameters, as well as their individual influence on MLSS, could be important for establishing training recommendations, which could lead to either an improvement in V_O2max or V_ Lamax by performing high intensity or low intensity exercise training, respectively. Furthermore the validity of V_ Lamax -test should be focused in further studies.
132

Synthesis with Perfect Atom Economy: Generation of Furan Derivatives by 1,3-Dipolar Cycloaddition of Acetylenedicarboxylates at Cyclooctynes

Banert, Klaus, Bochmann, Sandra, Ihle, Andreas, Plefka, Oliver, Taubert, Florian, Walther, Tina, Korb, Marcus, Rüffer, Tobias, Lang, Heinrich 25 September 2014 (has links)
Cyclooctyne and cycloocten-5-yne undergo, at room temperature, a 1,3-dipolar cycloaddition with dialkyl acetylenedicarboxylates 1a,b to generate furan-derived short-lived intermediates 2, which can be trapped by two additional equivalents of 1a,b or alternatively by methanol, phenol, water or aldehydes to yield polycyclic products 3b–d, orthoesters 4a–c, ketones 5 or epoxides 6a,b, respectively. Treatment of bis(trimethylsilyl) acetylenedicarboxylate (1c) with cyclooctyne leads to the ketone 7 via retro-Brook rearrangement of the dipolar intermediate 2c. In all cases, the products are formed with perfect atom economy.
133

Temperature-Compensated Force/Pressure Sensor Based on Multi-Walled Carbon Nanotube Epoxy Composites

Dinh, Nghia Trong, Kanoun, Olfa 10 November 2015 (has links)
In this study, we propose a multi-walled carbon nanotube epoxy composite sensor for force and pressure sensing in the range of 50 N–2 kN. A manufacturing procedure, including material preparation and deposition techniques, is proposed. The electrode dimensions and the layer thickness were optimized by the finite element method. Temperature compensation is realized by four nanocomposites elements, where only two elements are exposed to the measurand. In order to investigate the influence of the filler contents, samples with different compositions were prepared and investigated. Additionally, the specimens are characterized by cyclical and stepped force/pressure loads or at defined temperatures. The results show that the choice of the filler content should meet a compromise between sensitivity, temperature influence and noise behavior. At constant temperature, a force of at least 50N can be resolved. The measurement error due to the temperature influence is 150N in a temperature range of –20°C–50°C.
134

Behavior of Cathodic dip Paint Coated Fiber Reinforced Polymer/Metal Hybrids

Osiecki, Tomasz, Gerstenberger, Colin, Seidlitz, Holger, Hackert, Alexander, Kroll, Lothar 27 July 2015 (has links)
Increasing mechanical, economic and environmental requirements lead to multi material designs, wherein different classes of materials and manufacturing processes are merged to realize lightweight components with a high level of functional integration. Particularly in automotive industry the use of corresponding technologies will rise in the near future, as they can provide a significant contribution to weight reduction, energy conservation and therefore to the protection of natural resources. Especially the use of continuous fiber reinforced polymers (FRP) with thermoplastic matrices offers advantages for automotive components, due to its good specific characteristics and its suitability for mass production. In conjunction with isotropic materials, such as steel or aluminum, optimized lightweight structures can be produced, whose properties can be easily adapted to the given component requirements. The present paper deals with the development of innovative hybrid laminates with low residual stresses, made of thin-walled steel sheets and glass fiber reinforced thermoplastic (GFRP) prepregs layers. Thereby the interlaminar shear strength (ILSS) was increased by an optimization of the FRP/metal-interfaces, carried out by examining the influence of several pre-operations like sanding, cleaning with organic solvents and applying primer systems. Based on these findings optimized compound samples were prepared and tested under realistic Cathodic dip paint conditions to determine the influence on the ILSS.
135

Causes and Consequences of Schadenfreude and Sympathy: A Developmental Analysis

Schindler, Rose, Körner, André, Bauer, Sylvia, Hadji, Sarina, Rudolph, Udo 11 November 2015 (has links)
Moral judgments and moral emotions are a ubiquitous feature of social interactions. Humans decide quickly and intuitively whether an action is morally right or wrong. Schadenfreude and sympathy, as emotional reactions to the misfortunes of others, are prototypical moral emotions. So far, however, little evidence exists concerning children’s understanding of schadenfreude. Within three studies, we investigated the experience of schadenfreude and sympathy among N = 364 children of different age groups. We interviewed the children while showing them picture stories. In the picture stories, we varied the behavior of the protagonist prior to a misfortune: (1) whether his behavior had been morally right or wrong, (2) whether the protagonist attained his goal, (3) whether the protagonist was responsible for the misfortune. In addition, in one study we varied (4) the emotional relationship of the interviewed children to the protagonist. Furthermore, we asked the children to decide whether they want to sit next to the protagonist or do him a favor. Results show that children experience sympathy as well as schadenfreude at the age of 4 years. Sympathy is more likely to arise when the protagonists of a story are likable, when these actors typically pursue morally positive goals, and if they are not responsible for their misfortune. In contrast, schadenfreude is more likely when the protagonist is disliked, when actors pursue immoral goals and if they are responsible for their misfortune. In addition, sympathy increases approach (helping behavior, sitting next to the agent and doing favors), whereas schadenfreude increases avoidance tendencies.
136

Future Cognitive Ability: US IQ Prediction until 2060 Based on NAEP

Rindermann, Heiner, Pichelmann, Stefan 26 November 2015 (has links)
The US National Assessment of Educational Progress (NAEP) measures cognitive competences in reading and mathematics of US students (last 2012 survey N = 50,000). The long-term development based on results from 1971 to 2012 allows a prediction of future cognitive trends. For predicting US averages also demographic trends have to be considered. The largest groups’ (White) average of 1978/80 was set at M = 100 and SD = 15 and was used as a benchmark. Based on two past NAEP development periods for 17-year-old students, 1978/80 to 2012 (more optimistic) and 1992 to 2012 (more pessimistic), and demographic projections from the US Census Bureau, cognitive trends until 2060 for the entire age cohort and ethnic groups were estimated. Estimated population averages for 2060 are 103 (optimistic) or 102 (pessimistic). The average rise per decade is dec = 0.76 or 0.45 IQ points. White-Black and White-Hispanic gaps are declining by half, Asian-White gaps treble. The catch-up of minorities (their faster ability growth) contributes around 2 IQ to the general rise of 3 IQ; however, their larger demographic increase reduces the general rise at about the similar amount (-1.4 IQ). Because minorities with faster ability growth also rise in their population proportion the interactive term is positive (around 1 IQ). Consequences for economic and societal development are discussed.
137

Inkjet Printing of Colloidal Nanospheres: Engineering the Evaporation-Driven Self-Assembly Process to Form Defined Layer Morphologies

Sowade, Enrico, Blaudeck, Thomas, Baumann, Reinhard R. 12 November 2015 (has links)
We report on inkjet printing of aqueous colloidal suspensions containing monodisperse silica and/or polystyrene nanosphere particles and a systematic study of the morphology of the deposits as a function of different parameters during inkjet printing and solvent evaporation. The colloidal suspensions act as a model ink for an understanding of layer formation processes and resulting morphologies in inkjet printing in general. We investigated the influence of the surface energy and the temperature of the substrate, the formulation of the suspensions, and the multi-pass printing aiming for layer stacks on the morphology of the deposits. We explain our findings with models of evaporation-driven self-assembly of the nanosphere particles in a liquid droplet and derive methods to direct the self-assembly processes into distinct one- and two-dimensional deposit morphologies.
138

Crystal structure of 3-ferrocenyl-1-phenyl-1H-pyrrole, [Fe(η5-C5H4cC4H3NPh)(η5-C5H5)]

Pfaff, Ulrike, Korb, Marcus, Lang, Heinrich 13 May 2016 (has links)
The molecular structure of the title compound, [Fe(C 5 H 5 )(C 15 H 12 N)], consists of a ferrocene moiety with an N-phenylpyrrole heterocycle bound to one cyclopentadienyl ring. The 1,3-disubstitution of the pyrrole results in an L- shaped arrangement of the molecule with plane intersections of 2.78 (17)° between the pyrrole and the N-bonded phenyl ring and of 8.17 (18)° between the pyrrole and the cyclopentadienyl ring. In the crystal, no remarkable intermolecular interactions are observed.
139

Electromechanical Behavior of Chemically Reduced Graphene Oxide and Multi-walled Carbon Nanotube Hybrid Material

Benchirouf, Abderrahmane, Müller, Christian, Kanoun, Olfa 14 May 2016 (has links)
In this paper, we propose strain-sensitive thin films based on chemically reduced graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) without adding any further surfactants. In spite of the insulating properties of the thin-film-based GO due to the presence functional groups such as hydroxyl, epoxy, and carbonyl groups in its atomic structure, a significant enhancement of the film conductivity was reached by chemical reduction with hydro-iodic acid. By optimizing the MWCNT content, a significant improvement of electrical and mechanical thin film sensitivity is realized. The optical properties and the morphology of the prepared thin films were studied using ultraviolet-visible spectroscopy (UV-Vis) and scanning electron microscope (SEM). The UV-Vis spectra showed the ability to tune the band gap of the GO by changing the MWCNT content, whereas the SEM indicated that the MWCNTs were well dissolved and coated by the GO. Investigations of the piezoresistive properties of the hybrid nanocomposite material under mechanical load show a linear trend between the electrical resistance and the applied strain. A relatively high gauge factor of 8.5 is reached compared to the commercial metallic strain gauges. The self-assembled hybrid films exhibit outstanding properties in electric conductivity, mechanical strength, and strain sensitivity, which provide a high potential for use in strain-sensing applications.
140

Survey of Expert Opinion on Intelligence: Causes of International Differences in Cognitive Ability Tests

Rindermann, Heiner, Becker, David, Coyle, Thomas R. 26 August 2016 (has links)
Following Snyderman and Rothman (1987, 1988), we surveyed expert opinions on the current state of intelligence research. This report examines expert opinions on causes of international differences in student assessment and psychometric IQ test results. Experts were surveyed about the importance of culture, genes, education (quantity and quality), wealth, health, geography, climate, politics, modernization, sampling error, test knowledge, discrimination, test bias, and migration. The importance of these factors was evaluated for diverse countries, regions, and groups including Finland, East Asia, sub-Saharan Africa, Southern Europe, the Arabian-Muslim world, Latin America, Israel, Jews in the West, Roma (gypsies), and Muslim immigrants. Education was rated by N = 71 experts as the most important cause of international ability differences. Genes were rated as the second most relevant factor but also had the highest variability in ratings. Culture, health, wealth, modernization, and politics were the next most important factors, whereas other factors such as geography, climate, test bias, and sampling error were less important. The paper concludes with a discussion of limitations of the survey (e.g., response rates and validity of expert opinions).

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