211,799 research outputs found
Calculations of higher order collision integrals for use in the determination of transport coefficients of high temperature gases Final report
Viscosity and thermal conductivity of atomic hydroge
Identity and ethnicity in /t/ in Glasgow-Pakistani high-school girls
This paper presents an acoustic phonetic analysis
of Glasgow Asian syllable-initial /t/, in speech data
collected from Pakistani-Muslim girls in a
Glasgow high school after a long-term participant
observation into their shared and differing social
practices. The results show differences in spectral
energy and shape according to following phonetic
segment, and to membership in two contrasting
Communities of Practice, more conservative girls
maintaining traditional cultural practices, and more
rebellious girls whose behaviour challenges such
norms. The findings demonstrate that ethnicity is
integrally linked with locally-salient identity, and
hence that fine phonetic variation which indexes
ethnicity is in fact indexical of local ethnic identity
Improving Statistical Language Model Performance with Automatically Generated Word Hierarchies
An automatic word classification system has been designed which processes
word unigram and bigram frequency statistics extracted from a corpus of natural
language utterances. The system implements a binary top-down form of word
clustering which employs an average class mutual information metric. Resulting
classifications are hierarchical, allowing variable class granularity. Words
are represented as structural tags --- unique -bit numbers the most
significant bit-patterns of which incorporate class information. Access to a
structural tag immediately provides access to all classification levels for the
corresponding word. The classification system has successfully revealed some of
the structure of English, from the phonemic to the semantic level. The system
has been compared --- directly and indirectly --- with other recent word
classification systems. Class based interpolated language models have been
constructed to exploit the extra information supplied by the classifications
and some experiments have shown that the new models improve model performance.Comment: 17 Page Paper. Self-extracting PostScript Fil
Experimental study and evaluation of radioprotective drugs
Experimental study evaluates radioprotective drugs administered before exposure either orally or intravenously. Specifically studied are the sources of radiation, choice of radiation dose, choice of animals, administration of drugs, the toxicity of protective agents and types of protective drug
Ice formation on a smooth or rough cold surface due to the impact of a supercooled water droplet
Ice accretion is considered in the impact of a supercooled water droplet on a smooth or rough solid surface, the roughness accounting for earlier icing. In this theoretical investigation the emphasis and novelty lie in the full nonlinear interplay of the droplet motion and the growth of the ice surface being addressed for relatively small times, over a realistic range of Reynolds numbers, Froude numbers, Weber numbers, Stefan numbers and capillary underheating parameters. The Prandtl number and the kinetic under-heating parameter are taken to be order unity. The ice accretion brings inner layers into play forcibly, affecting the outer flow. (The work includes viscous effects in an isothermal impact without phase change, as a special case, and the differences between impact with and without freezing.) There are four main findings. First, the icing dynamically can accelerate or decelerate the spreading of the droplet whereas roughness on its own tends to decelerate spreading. The interaction between the two and the implications for successive freezings are found to be subtle. Second, a focus on the dominant physical effects reveals a multi-structure within which restricted regions of turbulence are implied. The third main finding is an essentially parabolic shape for a single droplet freezing under certain conditions. Fourth is a connection with a body of experimental and engineering work and with practical findings to the extent that the explicit predictions here for ice-accretion rates are found to agree with the experimental range.
Theoretical versus pragmatic design in qualitative research
For many years, discussions of the relative merits of generic and theoretical approaches to qualitative research have divided researchers while overshadowing the need to focus on addressing clinical questions. Drawing
on the challenges of designing a study that explored parents’ experiences of living with children with hydrocephalus, the authors of this paper argue that
over-adherence to, and deliberations about, the philosophical origins of qualitative methods is undermining the contributions qualitative research could make to evidence-based health care and suggest qualitative methods
should stand alone
Gravity flow rate of solids through orifices and pipes
Lock-hopper systems are the most common means for feeding solids to and from coal conversion reactor vessels. The rate at which crushed solids flow by gravity through the vertical pipes and valves in lock-hopper systems affects the size of pipes and valves needed to meet the solids-handling requirements of the coal conversion process. Methods used to predict flow rates are described and compared with experimental data. Preliminary indications are that solids-handling systems for coal conversion processes are over-designed by a factor of 2 or 3
Emissivity coatings for low-temperature space radiators Quarterly progress report, 1 Jan. - 31 Mar. 1966
Solar absorptance and emittance of candidate zinc oxides/silicone and zinc oxide/potassium silicate coatings measured at room temperature for application to space radiator
Study of payload sensor contamination
Epoxy/glass test specimens representing Scout fourth and fifth stage motor casings were prepared and studied in a test program designed to determine the relative contamination contributed to payload sensors located near the motor casings. The relative contamination detected in the test program was dependent on several factors, including: (1) distance of test specimen to sensor, (2) sensor temperature, (3) geometric position of the sensor (relative to test specimen), (4)test specimen temperature, (5) chemical composition of the test specimen, (6) sensor function, and (7) additional materials (such as adhesive-backed aluminum tape) added to the test specimens. The thermal characteristics and the decomposition and outgassing products were determined. These data were used to better understand the relative contamination data from the remote sensor testing
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