771 research outputs found
Letter, Addressed to William Easton Hutchison from Ida Callery, May 1916
A letter written by Ida Callery sent to an unidentified person on May 28, 1916
Studies in the fluoranthene series
1. It has been shown that in Friedel-Crafts reactions
acetylation, benzoylation and phthaloylation of
fluoranthene give the 4- and 11- substituted Isomers
in approximately equal quantities. In some cases a
small percentage of disubstituted compound Is also
formed. This is not in agreement with von Braun's
work which claimed that acylation occurred predominantly in the 12-(11-)- position with only small amounts
of the substituted isomer.2. 4-Benzoyl-fluoranthene and 4-acetyl-fluoranthene
were synthesised from 4-bromo-fluoranthene, by way
of the nitrile, with Grignard reactions. 4-o-Carboxybenzoyl-fluoranthene was decarboxylated to 4-
benzoyl-fluoranthene.3. A Friedel-Crafts reaction with oxalyl chloride
gave fluoranthene-11-carboxylic acid and fluoranthene-4:11-dicarboxylic acid in a ratio of 2:1. This
agrees with von Braun's results. A preparation of
the carboxylic acids by the Houben reaction gave
predominantly fluoranthene-11-carboxylic acid.4. Fluoranthene-4-carboxylic acid (prepared by acid
hydrolysis of 4-cyanofluoranthene) was easily
decarboxylated, whereas fluorantnene-11-carboxylic
acid was not. Fluoranthene 4:11-dicarboxylic acid
was decarboxylated to fluoranthene-11-carboxylic
acid,5. Benzoylation of l:2:5:4~tetrahydrofluoranthene
gave predominantly 4-benzoyl-5t5:7 :8-tetrahydrofluoranthene. This agrees with similar substitutions
carried out by von Braun.6. Benzoylation of naphthalene in nitrobenzene as
solvent gave a mixture of 54% α-benzoyl- and 46% Ă-
benzoyl-naphthalene.7. On oxidation with chromic anhydride in glacial
acetic acid and decarboxylation of the product, 4-benzoyl-fluoranthene yielded 2-benzeyl-fluorenone.
This proved definitely that the benzoyl group was in
the 4- position in the original bonzoyl-fluoranthene.8. Oxidation of 11-benzoyl-fluoranthene with chromic
anhydride in glacial acetic acid gave an acid which
was different from that obtained in 7. Decarboxylation gave 2-benzoyl-fluorenone which proved that
the benzoyl group was in the 11- position in the
original benzoyl-fluoranthene.9. Experiments to orientate a dibromofluoranthene were
not completed successfully. The oxidation product may
have been a monobromo-f'luorenone-carboxylic acid
The Chinese Invasion Threat: Taiwanâs Defense and American Strategy in Asia
https://digitalcommons.cedarville.edu/mens_basketball_videos/1108/thumbnail.jp
Student preconceptions and reality: A survey exercise to teach wealth inequality
This paper presents a way to enhance student interest and learning when teaching economic inequality. The approach draws on a well-known survey conducted by Norton and Ariely (2011). The approach involves surveying students, asking them to estimate the current level of wealth inequality in the US, and asking them to state their ideal level of wealth inequality. As in Norton and Ariely\u27s survey of a representative sample of Americans, our students underestimated actual wealth inequality and preferred a distribution of wealth for the US that was more equal than any country\u27s distribution. We suggest ways the student survey results can be presented and discussed. We also provide Stata code and an Excel workbook to ease effective classroom presentation of the survey results. This approach to beginning the study of inequality piqued our students\u27 interest and helped them understand how inequality is measured
Deaf STEM Community Alliance: Establishing a model virtual academic community
Abstract - This presentation describes the incremental and iterative development of the Deaf STEM Community Allianceâs virtual academic community, the Deaf and Hard of Hearing Virtual Academic Community (DHHVAC). The DHHVAC components address three critical barriers to the success of students who are deaf or hard-of-hearing: student preparation, socialization, and access to media
The effect of treated sewage effluent (urban wastewater) on the trichodinid (protozoa: ciliophora) communities ectozoic on three-spined sticklebacks, Gasterosteus aculeatus L.
Spectral Imaging Methods Applied to the Syriac Galen Palimpsest
The spectral imaging techniques applied to the so-called âSyriac Galen palimpsestâ in 2008-2010 are reported, including examples of results obtained. The imaging methods were adapted from those used on the Archimedes palimpsest during prior years, and are now comparatively elementary relative to methods that have been developed since. These recent advances will be outlined to demonstrate why improvements would be expected in newer imaging collections and processing
Modeling of Swarm Robotic Systems: A Case Study in Collaborative Distributed Manipulation
In this paper, we present a time-discrete, incremental methodology for modeling, at the microscopic and macroscopic level, the dynamics of distributed manipulation experiments using swarms of autonomous robots endowed with reactive controllers. The methodology is well-suited for nonspatial metrics since it does not take into account robotsâ trajectories or the spatial distribution of objects in the environment. The strength of the methodology lies in the fact that it has been generated by considering incremental abstraction steps, from real robots to macroscopic models, each with well-defined mappings between successive implementation levels. Precise heuristic criteria based on geometrical considerations and systematic tests with one or two real robots prevent the introduction of free parameters in the calibration procedure of models. As a consequence, we are able to generate highly abstracted macroscopic models that can capture the dynamics of a swarm of robots at the behavioral level while still being closely anchored to the characteristics of the physical set-up. Although this methodology has been and can be applied to other experiments in distributed manipulation (e.g., object aggregation and segregation, foraging), in this paper we focus on a strictly collaborative case study concerned with pulling sticks out of the ground, an action that requires the collaboration of two robots to be successful. Experiments were carried out with teams consisting of two to 600 individuals at different levels of implementation (real robots, embodied simulations, microscopic and macroscopic models). Results show that models can deliver both qualitatively and quantitatively correct predictions in time lapses that are at least four orders of magnitude smaller than those required by embodied simulations and that they represent a useful tool for generalizing the dynamics of these highly stochastic, asynchronous, nonlinear systems, often outperforming intuitive reasoning. Finally, in addition to discussing subtle numerical effects, small prediction discrepancies, and difficulties in generating the mapping between different abstractions levels, we conclude the paper by reviewing the intrinsic limitations of the current modeling methodology and by proposing a few suggestions for future work
Demonstration of a reusable mask in a tubular design that provides universal fit and protection from respiratory hazards
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