Search for Binary Protostars

In an effort to shed more light on the formation process of binary stars, we have started a program to study multiplicity among nearby low- and intermediate-mass protostars using the OVRO Millimeter Array. Here, we describe the project and present the first results on the protostellar core in the Bok globule CB230 (L1177). At 10 arcsec resolution, the molecular core is resolved into two components separated by 5000 AU. The morphology and kinematics of the double core suggest that it formed from a single cloud core due to rotational fragmentation.Comment: 4 pages, 2 figures, ALMA conference proceeding

A close view on the protoplanetary disk in the Bok globule CB26

We present new sub-arcsecond-resolution near-infrared polarimetric imaging and millimetre interferometry data on the circumstellar disk system in the Bok globule CB26. The data imply the presence of a M > 0.01 M_sun edge-on disk of >400 AU in diameter, being in Keplerian rotation around a young ~0.35 M_sun star. The mm dust emission from the inner 200 AU is highly optically thick, but the outer parts are optically thin and made of small dust grains. Planetesimal growth in the inner disk could neither be comfirmed nor excluded. The outer optically thin part of the disk is strongly warped. We argue that the CB 26 disk is a very young protoplanetary disk and show that it is comparable to the early solar system.Comment: Conference proceeding "Origins of stars and planets: The VLT view", ESO, Garching, April 24-27 200

The big problem of small change

Western Europe was plagued with currency shortages from the 14th century, at which a 'standard formula' had been devised to cure the problem. We use a cash-in-advance model of commodity money to define a currency shortage, show that they could develop and persist under commodity money regime, and analyze the role played by each ingredient in the standard formula. A companion paper documents the evolution of monetary theory, monetary experiments and minting technology over the course of six hundred years.Monetary theory ; Money ; Money theory

The Physical and Chemical Properties of Human Sweat and Factors Affecting the Water Balance in Confined Spaces Semiannual Status Report No. 2, 1 Jan. - 30 Jun. 1966

Physical and chemical properties of human sweat and factors affecting water balance in confined space

Development and collapse of an Oscillatoria bloom in Loch Leven during July 1994

During 1994, weekly spot-sampling of open water sites on Loch Leven took place from 16th March onwards. Very little difference between spot-sampling sites was observed from 16th March to 5th July. Throughout April and May there was a slow increase in levels of chlorophyll-a, followed by a rapid increase through June, reaching a maximum of 230 micrograms per litre. On 8th July there was a very rapid rise in water temperature, with a corresponding increase in dissolved oxygen and pH. At 0915 hours on 9th July there was a drop in all three variables. These changes were coincident with a marked reduction in chlorophyll-a values falling to 70 micrograms per litre on 12th July. On 16th July evidence of a resurgence of photosynthesis was observed

Effects of forward velocity on noise for a J85 turbojet engine with multitube suppressor from wind tunnel and flight tests

Flight and wind tunnel noise tests were conducted using a J85 turbojet engine as a part of comprehensive programs to obtain an understanding of forward velocity effects on jet exhaust noise. Nozzle configurations of primary interest were a 104-tube suppressor with and without an acoustically-treated shroud. The installed configuration of the engine was as similar as possible in the flight and wind tunnel tests. Exact simultaneous matching of engine speed, exhaust velocity, and exhaust temperature was not possible, and the wind tunnel maximum Mach number was approximately 0.27, while the flight Mach number was approximately 0.37. The nominal jet velocity range was 450 to 640 m/sec. For both experiments, background noise limited the jet velocity range for which significant data could be obtained. In the present tests the observed directivity and forward velocity effects for the suppressor are more similar to predicted trends for internally-generated noise than unsuppressed jet noise

Part I Electrochemically induced reactions of some halogenated organic compounds Part II novel rearrangements of pyridazine derivatives

The reduction of pentafluoropyridine gave, as the major products, octafluoro-4,4'-bipyridyl in aprotic systems and 4-H-tetrafluoropyridine with added proton donor. Garbanionic intermediates were not trapped by carbon dioxide to give acids. Voltammetric results for a series of polyfluoropyridines suggest that the negative charge in the radical anion is mainly in the 4-position. Reduotion of pentaohloropyridine in dime thylformamide gave 4-H-tetrachloropyridine, with some 4,4'-bistetraohloropyridylmeroury when using a mercury cathode. Intermediate carbanions were trapped by carbon dioxide, giving an acid mixture, which yielded 4-H-tetrachloropyridine and heptachlorobipyridyl on decarboxylation. Hexaohlorobenzene behaved similarly. Simple perfluoro-olefins eliminated fluoride ion on reduction and were subsequently oligomerised by it. Intermediate carbanions were trapped by water. The electrochemical products were high-boiling oils, resulting from reaction with the solvent. Oxidation of polyfluoroanisoles containing para hydrogen gave coupling to the corresponding 4,4'-dimethoxybiphenyl derivative. No coupling occurred when this position was blocked by fluorine. Trapping of intermediate radical cations with acetic acid was unproductive. PART II The photochemical and thermal rearrangements of a number of perfluoroalkylpyridazines in static systems was investigated. As had previously been reported, photolysis of perfluoro-4,5-dialkyl- pyridazines gave mainly perf1uoro-2,6-dialkylpyrazines, although in some cases perfluoro-2,6-dlal]sylpyrazines were also formed. The pyrolysis of perfluoro-4,5-clialkylpyridazines gave mainly perfluoro-4,5-dialkylpyrimidines and in some cases a small amount of the -2,5-pyrazine. Perfluoro-4-alkylpyridazines gave mixtures of perfluoro- 4-alkyl- and -5-alkylpyrimidines. These results can be explained by a mechanism involving diazabenzvalene Intermediates. The photolysis and pyrolysis of mixtures gave no exchange of substituent groups indicative of a bimolecular process. In the pyrolyses, the conversios of the less reactive pyridazlne was catalysed and that of the more reactive pyrldazlne Inhibited. The relative amounts rearranged ruled out a 1 : 1 Intermediate and a Slels-Alder mechanism, which would involve exchange of nitrogen, was further ruled out by (^15)N-labelling. The catalytic mechanism proposed Involves a transfer of vibrational excitation

Baseline tests of the C. H. Waterman Renault 5 electric passenger vehicle

The Waterman vehicle, a four passenger Renault 5 GTL, performance test results are presented and characterized the state-of-the-art of electric vehicles. It was powered by sixteen 6-volt traction batteries through a two-step contactor controller actuated by a foot throttle to change the voltage applied to the 6.7 -kilowatt motor. The motor output shaft was connected to a front-wheel-drive transaxle that contains a four-speed manual transmission and clutch. The braking system was a conventional hydraulic braking system