Atmospheric modeling for emergencies. An integrated system for responding to atmospheric releases of dangerous effluents within very short time periods

1983 ◽  
Vol 2 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Maynard E. Smith ◽  
John H. Carlson ◽  
John R. Martin ◽  
Frank J. Lawrence
Keyword(s):  
Atmospheric Modeling ◽  
Integrated System ◽  
Atmospheric Releases ◽  
Time Periods ◽  
Short Time

Recognition of Short Time Periods through Seriation

1977 ◽  
Vol 42 (4) ◽  
pp. 628-629 ◽  
Author(s):  
Clement W. Meighan
Keyword(s):  
Recent Article ◽  
Graphical Method ◽  
New Method ◽  
Time Discrimination ◽  
Time Periods ◽  
Short Time

One aspect of the recent article by Drennan (1976) merits some additional discussion. This has to do with the units of time that can be discriminated by seriation methods. One advance claimed for the new method proposed is that it allows for time placement within 25 years or so, stated as “ … finer than most traditional seriation.” In an article published 17 years ago, I showed this degree of time discrimination, with a much simpler graphical method of seriation.

scholarly journals How realistic are painted lightnings? Quantitative comparison of the morphology of painted and real lightnings: a psychophysical approach

2018 ◽  
Vol 474 (2214) ◽  
pp. 20170859 ◽  
Author(s):  
Mark Stromp ◽  
Alexandra Farkas ◽  
Balázs Kretzer ◽  
Dénes Száz ◽  
András Barta ◽  
...  
Keyword(s):  
Software Package ◽  
Relative Length ◽  
Quantitative Comparison ◽  
Angle Distribution ◽  
Morphological Parameters ◽  
Turning Angle ◽  
Local Maxima ◽  
Time Periods ◽  
Short Time ◽  
Number Of Branches

Inspired by the pioneer work of the nineteenth century photographer, William Nicholson Jennings, we studied quantitatively how realistic painted lightnings are. In order to answer this question, we examined 100 paintings and 400 photographs of lightnings. We used our software package to process and evaluate the morphology of lightnings. Three morphological parameters of the main lightning branch were analysed: (i) number of branches N b , (ii) relative length r , and (iii) number of local maxima (peaks) N p of the turning angle distribution. We concluded: (i) Painted lightnings differ from real ones in N b and N p . (ii) The r -values of painted and real lightnings vary in the same range. (iii) 67 and 22% of the studied painted and real lightnings were non-bifurcating ( N b  = 1, meaning only the main branch), the maximum of N b of painted and real lightnings is 11 and 51, respectively, and painted bifurcating lightnings possess mostly 2–4 branches, while real lightnings have mostly 2–10 branches. To understand these findings, we performed two psychophysical experiments with 10 test persons, whose task was to guess N b on photographs of real lightnings which were flashed for short time periods Δ t  = 0.5, 0.75 and 1 s (characteristic to lightnings) on a monitor. We obtained that (i) test persons can estimate the number of lightning branches quite correctly if N b  ≤ 11. (ii) If N b  > 11, its value is strongly underestimated with exponentially increasing difference between the real and estimated numbers. (iii) The estimation is independent of the flashing period Δ t of lightning photos/pictures. (iv) The estimation is more accurate, if skeletonized lightning pictures are flashed, rather than real lightning photos. These findings explain why artists usually illustrate lightnings with branches not larger than 11.

Scaling Issues in Landscape Ecology

2019 ◽  
pp. 14-41
Author(s):  
Kimberly A. With
Keyword(s):  
Landscape Ecology ◽  
Spatial Patterns ◽  
Spatial Scales ◽  
Ecological Data ◽  
Ecological Forecasting ◽  
Spatial And Temporal Scales ◽  
Time Periods ◽  
Patterns And Processes ◽  
Short Time ◽  
Over Time

Spatial patterns are ubiquitous in nature, and ecological systems exhibit patchiness (heterogeneity) across a range of spatial and temporal scales. Landscape ecology is explicitly concerned with understanding how scale affects the measurement of heterogeneity and the scale(s) at which spatial pattern is important for ecological phenomena. Patterns and processes measured at fine spatial scales and over short time periods are unlikely to behave similarly at broader scales and extended time periods. An understanding of pattern-process linkages, a major research focus in landscape ecology, thus requires an understanding of how patterns change with scale, spatially and temporally. The development of methods for extrapolating information across scales is necessary for predicting how landscapes will change over time as well as for ecological forecasting. This chapter explores how scaling issues affect ecological investigations, discusses problems in identifying the correct scale for research, and outlines when and how ecological data can be extrapolated.

scholarly journals The first in situ synthesis of 1,3-dioxan-5-one derivatives and their direct use in Claisen-Schmidt reactions

2019 ◽  
Vol 25 (1) ◽  
pp. 85-90 ◽  
Author(s):  
M. Javad Poursharifi ◽  
Mohammad M. Mojtahedi ◽  
M. Saeed Abaee ◽  
Mohammad M. Hashemi
Keyword(s):  
Acetic Acid ◽  
Aromatic Aldehydes ◽  
In Situ Synthesis ◽  
Stepwise Procedures ◽  
Time Periods ◽  
High Yields ◽  
Short Time ◽  
Direct Use ◽  
Derivatives Of

AbstractA method is developed for in situ generation of 1,3-dioxan-5-one derivatives 2. These compounds are simple precursors for accessing carbohydrate structures and previously had to be produced via stepwise procedures using excessive amounts of reagents. In the present work, three different derivatives of 2 were synthesized via the reaction of trialkoxyalkanes with dihydroxyacetone dimer 1 in the presence of acetic acid as the catalyst. In the same pot, derivatives of 2 were reacted with aromatic aldehydes and 30 mol% of pyrrolidine to obtain high yields of the respective bischalcones 3 within short time periods.

Ceramic Coatings for High Temperature Service

CORROSION ◽  
1960 ◽  
Vol 16 (7) ◽  
pp. 309t-311t ◽  
Author(s):  
S. W. BRADSTREET
Keyword(s):  
Ceramic Coating ◽  
Protective Coatings ◽  
Ceramic Coatings ◽  
Shear Stresses ◽  
Thermal Gradients ◽  
High Shear ◽  
Thermal Environments ◽  
Potential Value ◽  
Time Periods ◽  
Short Time

Abstract Several types of coatings may be used for service in extreme thermal environments. For moderate temperatures (to about 1700 C) for short time periods, these coatings may be rather simple refractory layers. Under the more severe conditions of ramjet and rocket operation, reinforced materials, graded substrate-coating interfaces, or multilayers are required. Where thermal gradients are severe and where high shear stresses and abrasion exist, composites must be used which utilize controlled ablation. The principles which appear to dominate the attachment of a ceramic coating to a variety of substrates are reviewed, and the deficiencies and advantages of different combinations are discussed. Principles for “tailoring” protective coatings for refractory metals is suggested, and a flame-sprayed ceramic coating of potential value as a combustion catalyst is used to illustrate these principles. 5.4.2

scholarly journals Vladimir Abramovich Rokhlin (23 August 1919 to 3 December 1984): Introductory note

1989 ◽  
Vol 9 (4) ◽  
pp. 605-608
Author(s):  
A. Katok
Keyword(s):  
Ergodic Theory ◽  
Measure Theory ◽  
The Other ◽  
Natural Evolution ◽  
And Topology ◽  
Introductory Note ◽  
Time Periods ◽  
The Right ◽  
Short Time ◽  
The Impact

The Ergodic Theory and Dynamical Systems journal pays tribute to V. A. Rokhlin, one of the founders of ergodic theory, a world-renowned topologist and geometer, and a man of tragic fate and exceptional courage. Rokhlin's mathematical heritage splits rather sharply into the ergodic theory – measure theory and topology – geometry parts. This fact has to do with a natural evolution of his interests but also with the keen sense of style in mathematics that Rokhlin possessed to an unusual degree. Naturally, we will concentrate on Rokhlin's contributions to ergodic theory and measure theory, his influence on other mathematicians working in those fields, and the development of some of his ideas. Fortunately, the topology part of Rokhlin's heritage has been superbly presented in Part I of the book ‘A la recherche de la topologie perdue’ published by Birkhaüser in Progress in Mathematics series (v. 62, 1986). The same cannot be said about the work on real algebraic geometry, Rokhlin's last big achievement. The impact of that work, carried out by his students, however, is very much felt now, and is very unlikely to be forgotten or neglected. On the other hand, his work in ergodic theory and measure theory, was restricted primarily to two relatively short time periods, 1947–1950 and 1959–1964, and for the most part was not followed by Rokhlin's immediate students. Hence, it runs a certain risk of being underestimated. We hope that the articles by A. Vershik; S. Yuzvinsky and B: Weiss, published in this issue, will put Rokhlin's work and his influence in ergodic theory into the right perspective.

A Review of Weather Routeing of Sailboats

1993 ◽  
Vol 46 (1) ◽  
pp. 113-129 ◽  
Author(s):  
Tim Thornton
Keyword(s):  
Time Periods ◽  
Short Time

A variety of different techniques has been developed for the weather routeing of sailboats. These have varied according to whether the technique is intended for yachts or for sail-assisted powered vessels, whether the routeing is for long or short time periods, and whether the routeing is used for navigation or design purposes.The techniques that have been implemented to date are reviewed, comparing their strengths and weaknesses. Ways in which these problems may be overcome in future implementations of weather routeing are also discussed

scholarly journals Bursts of amino acid replacements in protein evolution

2017 ◽  
Author(s):  
Anastasia V. Stolyarova ◽  
Georgii A. Bazykin ◽  
Tatyana V. Neretina ◽  
Alexey S. Kondrashov
Keyword(s):  
Amino Acid ◽  
Rapid Evolution ◽  
Synonymous Substitution ◽  
Time Interval ◽  
Short Time Interval ◽  
Baikal Lake ◽  
Rapid Changes ◽  
Time Periods ◽  
Short Time ◽  
Detailed Record

AbstractEvolution can occur both gradually and through alternating episodes of stasis and rapid changes. However, the prevalence and magnitude of fluctuations of the rate of evolution remains obscure. Detecting a rapid burst of changes requires a detailed record of past evolution, so that events that occurred within a short time interval can be identified. Here, we use the phylogenies of the Baikal Lake amphipods and of Catarrhini, which contain very short internal edges facilitating this task. We detect 6 radical bursts of evolution of individual proteins during such short time periods, each involving between 6 and 38 amino acid substitutions. These bursts were extremely unlikely to have occurred neutrally, and were apparently caused by positive selection. On average, in the course of a time interval required for one synonymous substitution per site, a protein undergoes a strong burst of rapid evolution with probability at least ~0.01.

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