Chromato-fluorographic drug detector

A drug detecting apparatus which includes a chromatographic system for separating particular substances from a sample solution passed through it is described. A source of radiation causes the substance to emit fluorescent radiation as it moves through the chromatographic system. An optical system spectrally separates the fluorescent radiation according to wavelength and for focusing particular portions of the separated spectrum through an exit aperture. A photodetector which is responsive to the radiation passing through the exit aperture develops an electrical signal commensurate with the intensity of the radiation. The electrical signal is recorded to provide an indication of certain characteristics of the substance

Chemical research projects office functions accomplishments programs

Basic and applied research in the fields of polymer chemistry, polymeric composites, chemical engineering, and biophysical chemistry is summarized. Emphasis is placed on fire safety and human survivability as they relate to commercial and military aircraft, high-rise buildings, mines and rapid transit transportation. Materials systems and other fire control systems developed for aerospace applications and applied to national domestic needs are described along with bench-scale and full-scale tests conducted to demonstrate the improvements in performance obtained through the utilization of these materials and fire control measures

Chemical research projects office: An overview and bibliography, 1975-1980

The activities of the Chemical Research Projects Office at Ames Research Center, Moffett Field, California are reported. The office conducts basic and applied research in the fields of polymer chemistry, computational chemistry, polymer physics, and physical and organic chemistry. It works to identify the chemical research and technology required for solutions to problems of national urgency, synchronous with the aeronautic and space effort. It conducts interdisciplinary research on chemical problems, mainly in areas of macromolecular science and fire research. The office also acts as liaison with the engineering community and assures that relevant technology is made available to other NASA centers, agencies, and industry. Recent accomplishments are listed in this report. Activities of the three research groups, Polymer Research, Aircraft Operating and Safety, and Engineering Testing, are summarized. A complete bibliography which lists all Chemical Research Projects Office publications, contracts, grants, patents, and presentations from 1975 to 1980 is included

Structural panels

Vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are disclosed. These vinylpyridines form copolymers with bismaleimides which copolymers have good fire retardancy and decreased brittleness. The cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone. Reinforced composites made from the cured copolymers are disclosed as well

Chemical modification of poly(p-phenylene) for use in ablative compositions

Development of ablative materials based on modification of polyphenylene compounds is discussed. Chemical and physical properties are analyzed for application as heat resistant materials. Synthesis of linear polyphenylenes is described. Effects of exposure to oxyacetylene flame and composition of resultant char layer are presented

Vinyl stilbazoles

Vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are disclosed. These vinylpyridines form copolymers with bismaleimides which copolymers have good fire retardancy and decreased brittleness. The cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone. Reinforced composites made from the cured copolymers are disclosed as well

Supportive guidance methods for wiki-based learning and knowledge construction

Wikis gelten als besondere Vertreter sozio-technischer Systeme, die zunehmend für die kollaborative Konstruktion von Wissen und darüber hinaus für individuelles und kollaboratives Lernen genutzt werden. Das grundlegende Design von Wiki-Systemen ermöglicht es den Nutzern, Inhalte als Artikel zu generieren und auf zugehörigen Diskussionsseiten ("`Talk Pages"') im Artikelhintergrund über Themen zu diskutieren. Aufbauend auf bestehenden Theorien und gegenwärtiger Forschung zum Wissensaufbau mit Wikis, und darüber hinaus aus dem Bereich des computergestützen kollaborativen Lernens (CSCL), wurden in dieser Dissertation mehrere Effekte auf Prozesse und Ergebnisse untersucht in Bezug auf zusätzliche ergänzende Strukturierungsmaßnahmen für wiki-basiertes Lernen. Konkret konzentrierte sich diese Arbeit auf (1) die Effektivität und Effizienz impliziter Lenkung für Wiki-Talk-Seiten, (2) die Auswirkungen zweier Ansätze von Kollaborationsskripten als explizite Lenkung zur Wissenskonstruktion mit Wikis und (3) die Relevanz spezifischer lernbezogener individueller Unterschiede für kollaboratives Lernen mit Wikis. Insgesamt wurden im Rahmen dieser Dissertation fünf empirische Studien durchgeführt. Mit Studie 1 wurden die Auswirkungen von visuellen Hervorhebungen kontroverser Argumentationen für Wiki-Diskussionen untersucht. Die Ergebnisse des Experiments zeigten, dass zusätzliche Hervorhebungen für kontroverse Diskussionen sich direkt auf das individuelle Selektions- und Leseverhalten sowie indirekt und in geringerem Maße auf die Lernergebnisse und die Qualität von Wiki-Beiträgen auswirken. In Studie 2 wurde untersucht, ob Visualisierungen von Autorenwissen und Beurteilungen durch die Wiki-Community implizit die Wahrnehmung die Leser von kontroversen Diskussionen in Wikis beeinflussen. Die Ergebnisse zeigten, dass, wenn zusätzliche Autoreninformationen visualisiert werden, es wahrscheinlicher ist, dass Leser von Wiki-Diskussionen der Argumentation eines angenommenen Experten folgen. In den Studien 3 und 4 wurden die Effekte zweier unterschiedlicher Kollaborationsskript-Ansätze untersucht. Das erste Skript wurde von Wikipedia abgeleitet, während das zweite Skript ein selbst entwickeltes Skript ist, das von empirischen Untersuchungen inspiriert wurde. Die Ergebnisse zeigten, dass der alternative Skriptvorschlag vorteilhafter ist in Bezug auf Perspektivübernahme und Integration widersprüchlicher Belege, sowie für den individuellen Lernerfolg und die Qualität kollaborativ bearbeiteter Artikel. Studie 5 untersuchte die Auswirkungen der Hervorhebungen für kontroverse Diskussionen und des alternativen Kollaborationsskripts im Zusammenspiel mit individuellen Unterschieden des kognitiven Geschlossenheitsbedürfnisses. Dieses Konstrukt ist relevant für das Verständnis, wie Menschen zweideutige Informationen verarbeiten, die in kontroversen Diskussionen zu finden sind. Die Ergebnisse zeigten, dass Personen mit einem hohen Bedürfnis nach kognitiver Geschlossenheit in Bezug auf den Lernerfolg mehr von den Hervorhebungen für kontroverse Diskussionen als implizite Lenkung profitieren, während Personen mit einem niedrigen Bedürfnis mehr von dem Kollaborationsskript als explizite Lenkung profitieren. Diese Studienreihe erweitert die empirische Basis der Forschung zu wiki-basierter Wissenskonstruktion und Lernprozessen um Untersuchungen zu ergänzenden unterschiedlichen Strukturierungsmaßnahmen und die Berücksichtigung individueller Unterschiede.Wikis are a special representative of socio-technical systems that are increasingly used for the collaborative construction of knowledge and furthermore for individual and collaborative learning. The basic design of wiki systems enables users to generate content as articles and as well to discuss about subject matters on corresponding discussion forums in the article background, the so-called talk pages. Building upon prevailing theories and previous research on knowledge building with wikis, and more broadly computer supported collaborative learning (CSCL) in general, this dissertation investigated several effects of added supplemental scaffolding measures for wiki-based learning on processes and outcomes. Specifically, this work focused on (1) the effectiveness and efficiency implicit guidance approaches for wiki talk pages, (2) the effects of two distinct collaboration scripts as explicit guidance for knowledge construction with wikis, and (3) the relevance of specific learning-related individual differences for collaborative learning with wikis. Overall, five empirical studies have been conducted as part of this dissertation. Study 1 examined the effects of added controversy awareness highlights for wiki discussions. Results of the experiment showed that added highlights for controversial discussions directly affect individual selection and reading behaviour, as well as indirectly and to a lesser extent the learning outcomes and wiki contribution quality. Study 2 examined whether visualisations of author expertise and community-rating implicitly affect the user perception of controversial discussions in wikis. Results showed that if additional author information is visualised, it is much more likely that readers of wiki discussions follow an assumed expert’s argumentation. Studies 3 and 4 both examined effects of two distinct collaboration script approaches. The first script was derived from Wikipedia, whereas the second script is a self-developed script that was inspired by related empirical research. Results showed that the alternative script proposal is more beneficial for perspective-taking and integration of opposing evidence, as well as for individual learning success and the quality of collaboratively edited articles. Study 5 examined the effects of the controversy awareness highlights and the alternative collaboration script in interaction with individual differences of the Need for Cognitive Closure. This construct is relevant for the understanding of how people process ambiguous information that are likely to be found in controversial discussions. Results showed that persons with a high Need for Cognitive Closure benefit more, in terms of learning success, from the controversy awareness highlights for implicit guidance, whereas persons with a low Need for Cognitive Closure benefit more from the collaboration script as explicit guidance. This study series extends the empirical base of research on wiki-based knowledge construction and learning processes with investigations of supplemental different guidance measures and the consideration of individual differences

Gold-induced nanowires on the Ge(100) surface yield a 2D, and not a 1D electronic structure

Atomic nanowires on semiconductor surfaces induced by the adsorption of metallic atoms have attracted a lot of attention as possible hosts of the elusive, Tomonaga-Luttinger liquid. The Au/Ge(100) system in particular is the subject of controversy as to whether the Au-induced nanowires do indeed host exotic, 1D metallic states. We report on a thorough study of the electronic properties of high quality nanowires formed at the Au/Ge(100) surface. High resolution ARPES data show the low-lying Au-induced electronic states to possess a dispersion relation that depends on two orthogonal directions in k-space. Comparison of the E(k$_x$,k$_y$) surface measured using ARPES to tight-binding calculations yields hopping parameters in the two different directions that differ by a factor of two. We find that the larger of the two hopping parameters corresponds, in fact, to the direction perpendicular to the nanowires (t$_{\perp}$). This, the topology of the $E$=$E_F$ contour in k$_{\||}$, and the fact that $t_{\||}$/$t_{\perp}\sim 0.5$ proves that the Au-induced electron pockets possess a 2D, closed Fermi surface, this firmly places the Au/Ge(100) nanowire system outside being a potential hosts of a Tomonaga-Luttinger liquid. We combine these ARPES data with STS measurements of the spatially-resolved electronic structure and find that the spatially straight conduction channels observed up to energies of order one electron volt below the Fermi level do not originate from the Au-induced states seen in the ARPES data. The former are more likely to be associated with bulk Ge states that are localized to the subsurface region. Despite our proof of the 2D nature of the Au-induced nanowire and sub-surface Ge-related states, an anomalous suppression of the density of states at the Fermi level is observed in both the STS and ARPES data, this phenomenon is discussed in the light of the effects of disorder.Comment: 17 pages, 8 figure

Interaction of guidance types and the Need for Cognitive Closure in wiki-based learning

One purpose of wikis is the collaborative generation of content. During creation processes, controversies between authors emerge that they discuss on the article’s talk page. Research suggests that controversies based on opposing points of view and contradictory evidence can be fruitful to trigger individual elaboration processes. However, previous research also showed that many wikis are not necessarily suited to identify relevant discussion contents and thus users need additional support as guidance. In an experimental laboratory study (N = 181) on wiki talk pages, we investigated two guidance measures in conjunction with the need for cognitive closure: (1) visual markers to highlight controversy status (implicit guidance) and (2) a collaboration script that directs users towards discussions (explicit guidance). Effects on wiki processes and learning outcomes were analysed. The results show that both guidance types can affect user behaviours, but in interaction with the individual Need for Cognitive Closure there were no meaningful effects. With respect to learning outcomes, we found an anticipated pattern for the interaction of the Need for Cognitive Closure with both guidance principles. The data provides support for differences in the learning success depending on the provided guidance type and the individual Need for Cognitive Closure