Sur l'existence d'une longueur élémentaire et d'un intervalle de temps élémentaire. II

1979 ◽  
Vol 57 (10) ◽  
pp. 1681-1685 ◽  
Author(s):  
Robert Lacroix
Keyword(s):  
Energy Band ◽  
Free Particle ◽  
Complete Agreement ◽  
Tunnel Effect ◽  
Time Interval ◽  
A Value

Giving a value for the elementary time interval t0 is the main purpose of this paper. For this, an analysis of the formula for the energy of a free particle is given, formula which has been found in our first paper on that subject. The value 4.4 × 10−24 s for t0 is in complete agreement with the results of our analysis. An energy band between 75 and 100 MeV is predicted as to be inaccessible for all particles at rest. The solution of the tunnel effect is given in the framework of our theory.

The asymptotic stage of longitudinal turbulent dispersion within a tube

1977 ◽  
Vol 80 (2) ◽  
pp. 293-303 ◽  
Author(s):  
R. Dewey ◽  
Paul J. Sullivan
Keyword(s):  
Turbulent Flows ◽  
Friction Velocity ◽  
Turbulent Dispersion ◽  
Time Interval ◽  
Longitudinal Diffusion ◽  
A Value ◽  
Discharge Velocity ◽  
Concentration Curves ◽  
Temporal Growth Rate ◽  
Short Times

This paper describes an experimental investigation of the conditions for which the asymptotic description of longitudinal dispersion given by Taylor (1954) would apply. At non-dimensional times following the release of a dye pulse that are significantly larger than those previously investigated, the integrated concentration curves were observed to be skewed. At relatively short times from release the concentration curves appear to be well described by the models presented by Sullivan (1971) and by Chatwin (1973). Some features of the asymptotic behaviour, namely the translation of the modal value of the integrated concentration curve at the discharge velocity and the constant temporal growth rate of the variance, are observed at the longest times following release. On the basis of these observations it is estimated that a non-dimensional time interval oftu*/d=O(105/R*), whereR*=u*d/v,u*is the friction velocity,vthe kinematic viscosity anddthe tube diameter, is required for the Taylor result to become applicable. Thus application of Taylor's theory is significantly restricted in turbulent flows, especially those with irregular boundaries and those that are not stationary. There the variations in the flow must be small with respect to an equivalent ‘development time’ if a value of the ‘local’ longitudinal diffusion coefficient is to have meaning.

Paraelektrische Resonanz und dielektrische Dispersion von Wasser in Beryll-Einkristallen / Paraelectric Resonance and Dielectric Dispersion of Water in Beryl Single Crystals

1974 ◽  
Vol 29 (11) ◽  
pp. 1558-1571
Author(s):  
H.-J. Rehm
Keyword(s):  
Electric Fields ◽  
Resonance Effect ◽  
Theoretical Description ◽  
Tunnel Effect ◽  
Zero Field ◽  
Zero Field Splitting ◽  
A Value ◽  
Axis Parallel ◽  
Electric Dipoles ◽  
The One

Paraelectric resonance spectra of beryl crystals are observed in the X-band region between 5 and 20 kV/cm under the condition that the external electric field F[101̅0]. Additional dielectric measurements show, that the paraelectric centres are the monomeric water molecules in the beryl cavities. For water dipoles in beryl only two orientations of the molecular a-axis relative to the crystal C6-axis are possible, and only those with their a-axis parallel to the C6-axis contribute to the paraelectric resonance effect. The electric moment vector µ of these latter molecules may rotate in the (0001)-crystal plane, i. e. around their own a-axis, and has a value of (1.9 ± 0.2) D. A theoretical description of paraelectric resonance is presented for a simplified model: the electric dipoles have 6 equivalent equilibrium positions along the [101̅0]-directions, tunnel effect and external electric fields remove the site degeneracy and we observe a molecular Stark splitting. We calculate a value of (2.0 ± 0.4) GHz for the zero-field splitting in the one-parameter Hamiltonian model.

Laser probe 40Ar/39Ar and conventional K/Ar dating of illites associated with the McClean unconformity-related uranium deposits, north Saskatchewan, Canada

1987 ◽  
Vol 24 (1) ◽  
pp. 10-23 ◽  
Author(s):  
C. J. Bray ◽  
E. T. C. Spooner ◽  
C. M. Hall ◽  
D. York ◽  
T. M. Bills ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Uranium Mineralization ◽  
Complete Agreement ◽  
Time Interval ◽  
Uranium Deposits ◽  
Class Interval ◽  
Laser Probe ◽  
Alteration Halo ◽  
Sheet Silicates ◽  
Sedimentary Layer

The McClean group of uranium deposits consists of elongate pods of high-grade uranium mineralization (width = ~ 15–40 m) tightly confined to within ±40 m of the basal unconformity. Uraninite–coffinite–sulphide/arsenide–chlorite–siderite mineralization at McClean is surrounded by a muscovite/illite ± haematite hydrothermal alteration halo,which can contain coffinite–pararammelsbergite (NiAs2) – muscovite/illite nodules. Ten laser probe 40Ar/39Ar dates, two of which are step-heat runs showing good plateaus, and 10 conventional K – Ar dates for this material show a distribution with asharp beginning at ~ 1320 Ma, a marked peak in the 1250–1200 Ma class interval, and a tail to dates as young as 1002 ± 33 (1σ) Ma. These determinations are in complete agreement with direct (U–Pb and Sm–Nd) dates on uraninite at the Midwest (e.g., 1328 ± 9 and 1110 ± 28 Ma), Key Lake (e.g., 1350 ± 4 and 1281 ± 6 Ma), and Collins Bay B deposits(e.g., 1281 ± 80 Ma). Since estimated depositional ages for the Athabasca sedimentary sequence are in the 1470 ± 15 to1428 ± 15 Ma range, uranium mineralization and associated hydrothermal alteration started ~ 100–150 Ma after Athabasca sedimentation, a result consistent with fluid-inclusion data, which indicate that mineralization took place at ~ 160–220 °C beneath ~ 3000 m of cover at a relatively advanced stage in the evolution of the basin. It is suggested that the similar initiation dates for uranium mineralization might reflect a widespread faulting event that affected the eastern part of the basin. A muscovite/illite closure temperature calculated from a measured argon diffusion activation energy of 36 ± 4 kcal/mol(1 kcal = 4.1868 kJ) indicates that the base of the Athabasca Basin in the McClean area has not been disturbed by temperatures greater than ~ 140 °C for 1.1–1.0 Ga. It is suggested that mineralization ceased when fracture permeability had been sealed by crystallization of secondary minerals. The duration of mineralization may have been ~ 150 Ma, a relatively long time interval not unreasonable for the base of a sedimentary basin.Secondary illites interstitial to quartz grains from the HLM1 stratigraphic borehole give 40Ar/39Ar ages of 1459 ± 4, 1341 ± 4, and 1113 ± 11 Ma, indicating that formation of diagenetic sheet silicates predated uranium mineralization. Recrystallization or formation of sheet silicates in relict sedimentary layers and in subunconformity altered basement referred to as "regolith" started at approximately the same time, since dates of 1484 ± 55 Ma (sedimentary layer), 1482 ± 49 Ma (regolith), and 1453 ± 49 Ma (regolith) have been obtained. Resetting of interstitial, sedimentary layer, and regolith sheet-silicate dates continued to ages of, for example, 1113 ± 11 Ma (interstitial) and 1038 ± 55 Ma (sedimentary layer), which exactly coincide with the youngest ages obtained for the alteration halo associated with mineralization.The youngest date obtained is a 40Ar/39Ar plateau age of 673 ± 3 Ma. The sample (2045-517) was obtained from within 2 mm of a concentrated pitchblende nodule and may have been disturbed in some way by its proximity to uranium.

scholarly journals New kinetic analysis of the Fenton reaction: Critical examination of the free radical – chain reaction concept

2019 ◽  
Vol 44 (4) ◽  
pp. 289-299
Author(s):  
Mordechai L Kremer
Keyword(s):  
Free Radical ◽  
Fenton Reaction ◽  
Critical Examination ◽  
Complete Agreement ◽  
Time Interval ◽  
Second Phase ◽  
Chain Reaction ◽  
Rapid Phase ◽  
Two Phases ◽  
Radical Model

Using [H2O2] in the molar range, the reaction with Fe2+ has two phases: in the first rapid phase, only a small fraction of the total O2 is evolved; the bulk of the gas is formed in a slow second phase. In interpretations based on the free radical model of Barb et al., the first phase has been identified with the ‘Fenton reaction’ (reaction of Fe2+with H2O2), while the second with catalytic decomposition of H2O2 by Fe3+ ions. This interpretation is not correct. A new analysis of the model shows that (1) it is a chain reaction having no termination steps and (2) the ‘Fenton part’ alone consists of two phases. It starts with rapid evolution of O2 via a five-membered chain reaction (first phase). When [Fe2+] becomes low, evolution of O2 continues in a three-membered chain reaction at a greatly reduced rate (second phase). In later stages of the second phase, Fe3+ catalysis contributes to O2 evolution. Thus, the amount of O2 formed in the rapid phase cannot be identified with the total amount formed in the ‘Fenton reaction’ but only with that formed in its first phase. Computer simulations of O2 evolution based on the model of Barb et al. and rate constants show a definite dependence of this quantity on the initial [H2O2] – in contrast to the experimentally found independence. More satisfactory, but not complete, agreement with measured data could be reached in simulations using a non-radical model. Some of the difficulty has been due to the determination of the exact position of the end of the first phase. The transition between the two phases of the reaction occurs in a short, but finite time interval. It has been shown that the quantity ‘total amount of O2 evolved in the Fenton reaction’ (subtracting the part due to Fe3+catalysis) is not accessible to experimental determination nor to theoretical calculation.

scholarly journals Definition and estimation of an actual reproduction number describing past infectious disease transmission: application to HIV epidemics among homosexual men in Denmark, Norway and Sweden

2004 ◽  
Vol 132 (6) ◽  
pp. 1139-1149 ◽  
Author(s):  
E. J. AMUNDSEN ◽  
H. STIGUM ◽  
J.-A. RØTTINGEN ◽  
O. O. AALEN
Keyword(s):  
Infectious Disease ◽  
Disease Transmission ◽  
Reproduction Number ◽  
Infectious Period ◽  
Secondary Case ◽  
Time Interval ◽  
Homosexual Men ◽  
Infectious Disease Transmission ◽  
A Value ◽  
The Common

Prevalence and incidence measures are the common way to describe epidemics. The reproduction number supplies information on the potential for growth or decline of an epidemic. We define an actual reproduction number for infectious disease transmission that has taken place. An estimator is suggested, based on the number of new infections observed in a given time-interval, the number of those infected at the start of the interval, and the length of the infectious period. That estimator is applied to HIV among men having sex with other men over the period, 1977–1995, in Scandinavia. The actual reproduction number was estimated with acceptable certainty from the period, 1981–1982, yielding a value of 15 secondary cases. A value of less than one secondary case was assessed for the period, 1988–1995, in Denmark and Sweden. The actual reproduction number gives us some additional understanding of the dynamics of epidemics, compared with prevalence and incidence curves.

scholarly journals INTEGRALS OVER PRODUCTS OF DISTRIBUTIONS FROM PERTURBATION EXPANSIONS OF PATH INTEGRALS IN CURVED SPACE

2002 ◽  
Vol 17 (15) ◽  
pp. 2019-2050 ◽  
Author(s):  
H. KLEINERT ◽  
A. CHERVYAKOV
Keyword(s):  
Singular Integrals ◽  
Equations Of Motion ◽  
Path Integrals ◽  
Complete Agreement ◽  
Time Interval ◽  
Perturbation Expansions ◽  
Curved Space ◽  
Infinite Time Interval ◽  
Definition Of ◽  
Products Of Distributions

We show that the requirement of coordinate invariance of perturbatively defined quantum-mechanical path integrals in curved space leads to an extension of the theory of distributions by specifying unique rules for integrating products of distributions. The rules are derived by using equations of motion and partial integration, while keeping track of certain minimal features stemming from the unique definition of all singular integrals in 1 - ∊ dimensions. Our rules guarantee complete agreement with much more cumbersome calculations in 1 - ∊ dimensions where the limit ∊ → 0 is taken at the end. In contrast to our previous papers where we solved the same problem for an infinite time interval or zero temperature, we consider here the more involved case of finite-time or temperature amplitudes.

scholarly journals PREDIKSI PELUANG KEMATIAN DAN KELAHIRAN MURNI PENDUDUK KABUPATEN MERAUKE MENGGUNAKAN METODE BIRTH AND DEATH PROCESS

2021 ◽  
Vol 15 (1) ◽  
pp. 095-102
Author(s):  
Minuk Riyana ◽  
Marius Agustinus Welliken K.
Keyword(s):  
Population Data ◽  
The Elderly ◽  
Death Process ◽  
Initial Time ◽  
Time Interval ◽  
Birth And Death Process ◽  
Female Sex ◽  
A Value ◽  
Calculation Results ◽  
Process Method

This study aims to estimate the probability of birth and death purely based on gender and population data of Merauke City. The chance of birth and death will be used to estimate the life table of the elderly in a population of the City of Merauke. The method used in this research is the birth and process method. The Birth and death process method which is a Poisson distribution is used to predict the chances of birth and death at time t. If the birth and death process fulfills the linearity requirements, then the processes are called the Yule-Furry process. This research discusses the stochastic process of pure birth-death with two sexes in the Yule-Furry Process. From the data on the population of Merauke district which is divided based on the sex of men and women using the pure birth and death model, the calculation results show that the probability value at the time interval 0 ≤ t <1 hour, at the initial time t = 0, the chance of individual birth at female sex is stationary at a value of 0.1762, while the chance of individual death for female sex is stationary at a value of 0.00154. The odds of birth and death in male individuals are stationary at a value of 0.305034 and 0, 059487.

An Efficient Method for Frequent Itemset Mining on Temporal Data

2019 ◽  
pp. 558-568
Author(s):  
Fathima Sherin T K ◽  
Anish Kumar B.
Keyword(s):  
Data Mining ◽  
Computation Time ◽  
Frequent Itemsets ◽  
Frequent Itemset ◽  
Frequent Itemset Mining ◽  
Edge Density ◽  
Time Interval ◽  
Related Data ◽  
Itemset Mining ◽  
A Value

Frequent itemset mining (FIM) is a data mining idea with extracting frequent itemset from a database. Finding frequent itemsets in existing methods accept that datasets are static or steady and enlisted guidelines are pertinent all through the total dataset. In any case, this isn't the situation when information is temporal which contains time-related data that changes data mining results. Patterns may occur during all or at specific interims, to limit time interims, frequent itemset mining with time cube is proposed to manage time arranges in the mining technique. This is how patterns are perceived that happen occasionally, in a period interim, or both. Thus, this paper mostly centres around developing up a productive calculation to mine frequent itemsets and their related time interval from a value-based database by expanding from the earlier calculation dependent on support and density as another edge. Density is proposed to deal with the overestimated timespan issue and to ensure the authenticity of the patterns found. As an extension from the current framework, here the density rate and minimum threshold is dynamically generated which is user determined parameter previously. Likewise, an analysis concerning time is made between dataset with partitioning and without apportioning the dataset, which shows computation time is less on account of partitioning technique.

scholarly journals Error growth and dynamical vectors during southern hemisphere blocking

2004 ◽  
Vol 11 (1) ◽  
pp. 99-118 ◽  
Author(s):  
M. Wei ◽  
J. S. Frederiksen
Keyword(s):  
Southern Hemisphere ◽  
Normal Modes ◽  
Time Interval ◽  
Random Perturbations ◽  
Time Intervals ◽  
Amplification Factors ◽  
Fast Growing ◽  
A Value ◽  
The Mean ◽  
Basic States

Abstract. The structural organization of initially random perturbations or "errors" evolving in a barotropic tangent linear model with time-dependent basic states taken from observations, is examined for cases of block development, maturation and decay in the Southern Hemisphere atmosphere during April, November and December 1989. We determine statistical results relating the structures of evolved errors to singular vectors (SVs), Lyapunov vectors (LVs) and finite-time normal modes (FTNMs). The statistics of 100 evolved error fields are studied for six day periods or longer and compared with the growth and structures of leading fast growing SVs, LVs and FTNMs. The SVs are studied in the kinetic energy (KE), enstrophy (EN) and streamfunction (SF) norms, while all FTNMs and the first LV are norm independent. The mean of the largest pattern correlations between the 100 error fields and dynamical vectors, taken over the five fastest growing SVs, in any of the three norms, or over the five fastest growing FTNMs, increases with increasing time interval to a value close to 0.6 after six days. Corresponding pattern correlations with the five fastest growing LVs are slightly lower. The leading dynamical vectors (SVs 1, FTNM1 or LV 1) generally, but not always, give the largest pattern correlations with the error fields. It is found that viscosity slightly increases the average correlations between the evolved errors and LV 1 and evolved SVs 1. Mean pattern correlations with fast growing dynamical vectors increase further for time intervals longer than six days. The properties of the dynamical vectors during Southern Hemisphere blocking are briefly outlined. After a few days integration, the structures of the leading evolved SVs in the KE, EN and SF norms, are in general quite similar and also similar to some of the dominant FTNMs that are norm independent. For optimization times of six days or less, the evolved SVs and FTNMs are, in general, different from the dominant LVs on the same day. Nevertheless, amplification factors of the first FTNMs and first LVs are very similar, and also similar to, but slightly larger than, the mean amplification factor of 100 initially random perturbations in the SF norm, while the amplification factors in the SF norm of KE SVs 1 and SF SV 1 are much higher. For longer optimization times, the first SVs and the first FTNM increasingly turn towards the leading LV with convergence achieved within a month.

NEGATIVE NUMBERS AND ANTIMATTER PARTICLES

2012 ◽  
Vol 21 (01) ◽  
pp. 1250005 ◽  
Author(s):  
UNG CHAN TSAN
Keyword(s):  
Complete Agreement ◽  
Negative Numbers ◽  
Arithmetic Properties ◽  
A Value ◽  
Great Hope ◽  
Baryonic Number ◽  
The Standard Model ◽  
The Difference ◽  
A Charge ◽  
Precise Testing

Dirac's equation states that an electron implies the existence of an antielectron with the same mass (more generally same arithmetic properties) and opposite charge (more generally opposite algebraic properties). Subsequent observation of antielectron validated this concept. This statement can be extended to all matter particles; observation of antiproton, antineutron, antideuton … is in complete agreement with this view. Recently antihypertriton was observed and 38 atoms of antihydrogen were trapped. This opens the path for use in precise testing of nature's fundamental symmetries. The symmetric properties of a matter particle and its mirror antimatter particle seem to be well established. Interactions operate on matter particles and antimatter particles as well. Conservation of matter parallels addition operating on positive and negative numbers. Without antimatter particles, interactions of the Standard Model (electromagnetism, strong interaction and weak interaction) cannot have the structure of group. Antimatter particles are characterized by negative baryonic number A or/and negative leptonic number L. Materialization and annihilation obey conservation of A and L (associated to all known interactions), explaining why from pure energy (A = 0, L = 0) one can only obtain a pair of matter particle antimatter particle — electron antielectron, proton and antiproton — via materialization where the mass of a pair of particle antiparticle gives back to pure energy with annihilation. These two mechanisms cannot change the difference in the number of matter particles and antimatter particles. Thus from pure energy only a perfectly symmetric (in number) universe could be generated as proposed by Dirac but observation showed that our universe is not symmetric, it is a matter universe which is nevertheless neutral. Fall of reflection symmetries shattered the prejudice that there is no way to define in an absolute way right and left or matter and antimatter. Experimental observation of CP violation aroused a great hope for explaining why our universe is not exactly matter antimatter symmetric. Sakharov stated that without the violation of baryonic number, it is not possible to obtain from pure energy a universe made of only matter. The fact that our universe is asymmetric (in number) but perfectly neutral, points toward the existence of a hypothetic interaction violating A and L but conserving all charges. This Matter Creation (MC) interaction creating either a pair of matter particles or antimatter particles (instead of a pair of particle antiparticle) would have a charge BAL = (A-L) and a neutral messenger Z*. Even if CP is conserved, MC would allow the creation of a number of matter particles not exactly equal to the number of antimatter particles. Our universe would then correspond to the remaining excess when all matter antimatter pairs have disappeared. Observation of matter nonconservation processes would be of great interest to falsify this speculation. In a plan with A and L as axes, pure energy is represented by the origin (A = 0, L = 0). A symmetric universe is also represented by (A = 0, L = 0) meaning that there are exactly the same number of baryons and antibaryons, and the same number of leptons and antileptons. Our present matter universe is instead represented by a point of the diagonal with A = L = present A value. This value is tiny relative to the number of gammas resulting from the annihilation of matter–antimatter particles.

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