Reactive-flow computations on a massively parallel computer

Results are described of recent research and model developments for performing large-scale multidimensional compressible reacting-flow computations on the Connection Machine, a very fine-grained, parallel computer capable of multigigaflop performance. We are interested both in having general-purpose computer programs for routine production computations and in evaluating the architecture of the computer for a wide range of computational fluid dynamics and reacting-flow applications. We describe the hurdles involved in rethinking the structure and the algorithms to best suit this kind of computer, provide some relative timings for different programs, and describe ways of dealing with special constraints (such as periodic boundary conditions) imposed by the architecture. Finally, representative results are presented for several reacting and nonreacting computations, including the development and propagation of a spark in a hydrogen-oxygen mixture, an imploding detonation, and the generation of beam-channel turbulence.     

A demand adjustment process

The aspiration approach to cooperative games, which has been studied by a number of authors, including Cross, Turbay, Albers, Selten and Bennett, presumes that players in a game bargain over their reservation prices, or aspirations. A number of aspiration-based solution concepts have been put forth, and aspiration solutions have been connected to non-cooperative bargaining models. Missing in this approach has been theory of how aspirations themselves arise. The present paper is an attempt to fill this gap. It describes a very general demand adjustment process, using the framework of set-valued dynamical systems developed by Maschler and Peleg. This demand adjustment process always converges; sufficient conditions are given in order that it converge to an aspiration, and that it converge in a finite number of steps.     

Frequency and effects of teachers'' voice problems

This study compared the frequency and effects of voice symptomsin teachers to a group of individuals employed in other occupations. Teachers were more likely to report having a voice problem (15 vs. 6%), having 10 specific voice symptoms, and having 5 symptoms of physical discomfort. They averaged almost 2 symptoms compared with none for nonteachers. Likewise, teachers were more likely to perceive that a voice problem would adversely affect their future career options, had done so in the past, and was limiting their current job performance. Over 20% of teachers but none of the nonteachers had missed any days of work due to a voice problem. These findings suggest that teaching is a high-risk occupation for voice disorders and that this health problem may have significant work-related and economic effects.     

Speech breathing during reading in women withvocal nodules

This study examined speech breathing patterns during reading bywomen with bilateral vocal fold nodules judged as mildly dysphonic and by women without vocal nodules. Although it might be predictable that the speech breathing patterns of individuals with laryngeal dysfunction will differ from those without laryngeal dysfunction, there is a lack of empirical data to support such assumptions.The results of the current study indicated that glottal airflow was greaterduring reading for the women with vocal nodules and that a larger volume of air was expended both per syllable and per breath group during reading. The rate of speech did not significantly differ between the two groups of women. There was no significant difference for the average duration of the breath groups and no significant difference for the number of syllables spoken per breath group. Additionally, both groups of women demonstrated a similar pattern of inspiratory pause location during the reading. The results suggest that speech breathing patterns associated with dysphonia be examined independently to distinguish specifically the nature of the interaction between the laryngeal dysfunction and the speech breathing pattern. Certainly, more information on how the severity of a voice disorder influences speech breathing is necessary.     

The application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)

Journal of Radioanalytical and Nuclear Chemistry - In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched...     

PNA forms an i-motif

A C-rich PNA hexanucleotide, p(C5T), has been shown to form an i-motif by nanoelectrospray ionization mass spectrometry coupled with H/D exchange, to have thermal stability comparable with its DNA analogue, but to exist over a much narrower pH range.     

Synthesis of endo-(3-azabicyclo[3.1.0]hex-6-yl)-methanol and derivatives as new geometric/charge mimics of glycosyltransfer transition states

The syntheses of azabicyclo[3.1.0]hexane transition state (TS) analogs are described. Cyclopropanation of N-Boc-3-pyrroline with ethyl diazoacetate afforded a 1.6:1 exo/endo ratio of the resulting ester. Reduction of the endo-isomer with LiAlH₄ yielded the alcohol which was phosphorylated, or iodinated to provide access to aglycon containing TS analogs.     

Cyclophanes. I,Topics in Current Chemistry,Vol. 113 : Editor F. Vögtle; Springer-Verlag,Berlin/Heidelberg/New York/Tokyo, 1983, 185 pages,DM 86.

An X-ray analysis of [Os(CO)₄AuPPh₃₂] shows that the metal atoms define an isosceles triangle in which the Au-Au distance is 2.929(1) Å, which is ca. 0.1 Å shorter than in the corresponding iron analogue [Fe(CO)₄AuPPh₃₂].