Analyzation of marine snow and fecal pellets collected in sediment trap CBi-2 off Cape Blanc, Mauritania

We analyzed size-specific dry mass, sinking velocity, and apparent diffusivity in field-sampled marine snow, laboratory-made aggregates formed by diatoms or coccolithophorids, and small and large zooplankton fecal pellets with naturally varying content of ballast materials. Apparent diffusivity was measured directly inside aggregates and large (millimeter-long) fecal pellets using microsensors. Large fecal pellets, collected in the coastal upwelling off Cape Blanc, Mauritania, showed the highest volume-specific dry mass and sinking velocities because of a high content of opal, carbonate, and lithogenic material (mostly Saharan dust), which together comprised ~80% of the dry mass. The average solid matter density within these large fecal pellets was 1.7 g cm**-3, whereas their excess density was 0.25 ± 0.07 g cm**-3. Volume-specific dry mass of all sources of aggregates and fecal pellets ranged from 3.8 to 960 µg mm**-3, and average sinking velocities varied between 51 and 732 m d**-1. Porosity was >0.43 and >0.96 within fecal pellets and phytoplankton-derived aggregates, respectively. Averaged values of apparent diffusivity of gases within large fecal pellets and aggregates were 0.74 and 0.95 times that of the free diffusion coefficient in sea water, respectively. Ballast increases sinking velocity and, thus, also potential O2 fluxes to sedimenting aggregates and fecal pellets. Hence, ballast minerals limit the residence time of aggregates in the water column by increasing sinking velocity, but apparent diffusivity and potential oxygen supply within aggregates are high, whereby a large fraction of labile organic carbon can be respired during sedimentation.

Automotive energy efficiency program. Presented papers.

Transportation Department, Office of the Assistant Secretary for Systems Development and Technology, Washington, D.C.

Augmentation of research and analysis capabilities for timely support of automotive fuel economy activities. Volume II: appendices A through C. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Augmentation of research and analysis capabilities for timely support of automotive fuel economy activities. Volume III: appendix D. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

An experimental study of highway aerodynamic interferences. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Augmentation of research and analysis capabilities for timely support of automotive fuel economy activities. Volume I: summary. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Evaluation of techniques for reducing in-use automobile fuel consumption. Final report.

National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.

Pontus Wikners vittra skrifter, i urval utg. af Karl Warburg.

Cover has imprint: Stockholm, A. Bonnier.

The slow motion of a permanently magnetized sphere in an electrically conducting medium,

"Research supported by the McDonnell Aircraft Corporation under Contract no. 6140-20 P.O. 7S4899-R and by the Purdue Research Foundation."

On the use of impact theory for slender configurations exhibiting flow separation /

Photocopy.

Begripliga webbtexter : En undersökning av begripligheten i Sollentuna kommuns webbtexter

I denna uppsats analyserar jag några av texterna på Sollentuna kommuns webbplats. Syftet är att undersöka begripligheten i texterna. Jag har låtit en fokusgrupp läsa och diskutera hur de upplever fyra webbtexter. Utifrån gruppens synpunkter har jag gjort en textanalys. Analysen bygger på den systemisk-funktionella lingvistikens tre metafunktioner: den ideationella, den interpersonella och den textuella. Jag har kopplat metafunktionerna till det pragmatiska synsättet, som menar att en begriplig text leder till att mottagarnas läsmål uppfylls, till exempel att mottagarna med hjälp av texten kan utföa handlingar av olika slag. Undersökningens resultat visar att alla fyra webbtexterna innehåller drag som kan försämra begripligheten. De brister som var lättast att koppla till direkta begriplighetsproblem hos fokusgruppen låg på det ideationella planet, som huvudsakligen avser textens innehåll. Framför allt gällde det avsaknad av viktig information men också att huvudämnet inte framgick tillräckligt tydligt. Brister på det textuella planet, som främst avser den språkliga formen, var något svårare att knyta till direkta begriplighetsproblem. I ett par fall gjorde dock texternas komplexa och abstrakta form att fokusgruppen blev osäker på innehållet. Brister på det interpersonella planet, som avser relationen mellan sändaren och mottagaren i texten, var svårast att koppla till fokusgruppens förståelse. Det gällde avsaknad av du-tilltal och direkta uppmaningar. 

Phonological features of Yazghulami : A field study

Yazghulami is a South-East Iranian language spoken in the Pamir area of Tajikistan by about 9000 people. This study gives an account of the phonology of the language by describing contrastive segments and their distribution and realizations, as well as describing suprasegmental features such as syllable structure and stress patterns. Field research was carried out in a community of Yazghulami speakers in Dushanbe, the capital of Tajikistan, by recording, transcribing and annotating spoken language. Yazghulami is analyzed as having 8 vowel phonemes of which one pair contrasts in length, and 36 consonant phonemes with a considerable display of palatal, velar and uvular phonemes, of which a set of three labialized plosives and three labialized fricatives is found. The syllable structure of Yazghulami allows for clusters of no more than two consonants in the onset and two in the coda; clusters in both positions do not occur in one and the same syllable. The stress generally falls on the last syllable of a word, although when nouns are inflected with suffixes, the stress instead falls on the last syllable of the stem. With these results, a foundation for further efforts to develop and increase the status of this endangered language is laid.

Delayed traveling ionospheric disturbances, especially in equatorial regions, following geomagnetic activity

For the Western-Pacific region spread-F has been found to occur with delays after geomagnetic activity (GA) ranging from 5 to 10 days as station groups are considered from low midlatitudes to equatorial regions. The statistical (superposed-epoch) analyses also indicate that at the equator the spread-F, and therefore associated medium-scale traveling ionospheric disturbances (MS-TIDs) occur with additional delays around 16, 22 and 28 days representing a 6-day modulation of the delay period. These results are compared with similar delays, including the modulation, for D-region enhanced hydroxyl emission (Shefov, 1969). It is proposed that this similarity may be explained by MS-TIDs influencing both the F and D regions as they travel. Long delays of over 20 days are also found near the equator for airglow-measured MS-TIDs (Sobral et al., 1997). These are recorded infrequently and have equatorward motions, while normally eastward motions are measured at the equator. Also in midlatitudes D-region absorption events have been shown (statistically) to have similar long delays after GA. It is suggested that atmospheric gravity waves and associated MS-TIDs may be generated by some of the precipitations responsible for the absorption. The recording of the delayed spread-F events depends on the GA being well below the average levels around sunset on the nights of recording. This implies that lower upper-atmosphere neutral particle densities are necessary.

Three-component force measurements on a large scramjet in a shock tunnel

A stress-wave force balance for measurement of thrust, lift, and pitching moment on a large scramjet model (40 kg in mass, 1.165 in in length) in a reflected shock tunnel has been designed, calibrated, and tested. Transient finite element analysis was used to model the performance of the balance. This modeling indicates that good decoupling of signals and low sensitivity of the balance to the distribution of. the load can be achieved with a three-bar balance. The balance was constructed and calibrated by applying a series of point loads to the model. A good comparison between finite element analysis and experimental results was obtained with finite element analysis aiding in the interpretation of some experimental results. Force measurements were made in a shock tunnel both with and without fuel injection, and measurements were compared with predictions using simple models of the scramjet and combustion. Results indicate that the balance is capable of resolving lift, thrust, and pitching moments with and without combustion. However vibrations associated with tunnel operation interfered with the signals indicating the importance of vibration isolation for accurate measurements.

Experimental expansion tube study of the flow over a toroidal ballute

An experimental investigation of high-enthalpy flow over a toroidal ballute (balloon/parachute) was conducted in an expansion tube facility. The ballute, proposed for use in a number of future aerocapture missions, involves the deployment of a large toroidal-shaped inflatable parachute behind a space vehicle to generate drag on passing through a planetary atmosphere, thus, placing the spacecraft in orbit. A configuration consisting of a spherical spacecraft, followed by a toroid, was tested in a superorbital facility. Measurements at moderate-enthalpy conditions (15-20 MJ/kg) in nitrogen and carbon dioxide showed peak heat transfer rates of around 20 MW/m(2) on the toroid. At higher enthalpies (>50 MJ/kg) in nitrogen, carbon dioxide, and a hydrogen-neon mixture, heat transfer rates above 100 MW/m(2) were observed. Imaging using near-resonant holographic interferometry showed that the flows were steady except when the opening of the toroid was blocked.