scholarly journals Continuous Rate Modelling of bacterial stochastic size dynamics

2020 ◽  
Author(s):  
Cesar Nieto ◽  
Cesar Vargas-Garcia ◽  
Juan Pedraza
Keyword(s):  
Size Distribution ◽  
Stochastic Dynamics ◽  
Jump Processes ◽  
Translation Invariance ◽  
Continuous Growth ◽  
Central Moments ◽  
Bacterial Division ◽  
Auto Correlation Function ◽  
Size Heterogeneity ◽  
Different Sources

AbstractBacterial division is an inherently stochastic process. However, theoretical tools to simulate and study the stochastic transient dynamics of cell-size are scarce. Here, we present a general theoretical approach based on the Chapman-Kolmogorov formalism to describe these stochastic dynamics including continuous growth and division events as jump processes. Using this approach, we analyze the effect of different sources of noise on the dynamics of the size distribution. Oscillations in the distribution central moments were found as consequence of the discrete translation invariance of the system with period of one doubling time, these oscillations are found in both the central moments of the size distribution and the auto-correlation function and do not disappear including stochasticity on division times or size heterogeneity on the population but only after include noise in either growth rate or septum position.

scholarly journals PyEcoLib: a python library for simulating E. coli stochastic size dynamics

2020 ◽  
Author(s):  
Camilo Blanco ◽  
Cesar Nieto ◽  
Cesar Vargas ◽  
Juan Pedraza
Keyword(s):  
Cell Size ◽  
Stochastic Dynamics ◽  
Jump Process ◽  
Fixed Number ◽  
Discrete Events ◽  
Continuous Processes ◽  
Continuous Growth ◽  
E Coli ◽  
Bacterial Division ◽  
Arbitrary Precision

Recent studies describe bacterial division as a jump process triggered when it reaches a fixed number of stochastic discrete events at a rate depending on the cell-size. This theoretical approach enabled the computation of stochastic cell-size transient dynamics with arbitrary precision, with the possibility of being coupled to other continuous processes as gene expression. Here we synthesize most of this theory in the tool PyEcoLib, a python-based library to estimate bacterial cell size stochastic dynamics including continuous growth and division events. In this library, we include examples predicting statistical properties seen in experiments.

The size distribution and surface area of soot emitted by different sources

2000 ◽  
Vol 31 ◽  
pp. 706-707
Author(s):  
A. Smekens ◽  
P. Berghmans ◽  
R. Van Grieken
Keyword(s):  
Size Distribution ◽  
Surface Area ◽  
Different Sources

scholarly journals Editorial

2019 ◽  
Vol 30 (5) ◽  
pp. 829-829
Author(s):  
R. Kuske ◽  
D. Yurchenko
Keyword(s):  
Stochastic Models ◽  
Stochastic Dynamics ◽  
Single Issue ◽  
Stochastic Effects ◽  
Multi Scale ◽  
Multiscale Dynamics ◽  
New Methodologies ◽  
Spatio Temporal ◽  
Multi Mode ◽  
Different Sources

The origin of this special issue took place at the 9th European Nonlinear Dynamics Conference (ENOC 2017) in Budapest, Hungary. Specifically, the mini-symposium on Random Dynamical Systems – Recent Advances and New Directions brought together novel perspectives on analyzing stochastic dynamics with applications including biology, structural dynamics, control, energy and mechanics. The expanded use of stochasticity in more realistic models exposes questions related to bifurcations, meta-stability, tipping and early warning signals, multiscale dynamics, and connections between chaos and stochastic dynamics. The observed phenomena in applications drive new methodologies and analyses, needed to understand the interplay between different sources of stochastic effects and nonlinearities, network structure, multi-mode and multi-scale behavior, non-smooth dynamics, energy transfer, and spatio-temporal phenomena. Of course, a single issue cannot hope to cover all of the new topics in stochastic analysis for applications. Nevertheless, we hope that the collection of applications and stochastic models presented in this issue illustrates some of the exciting advances and perspectives relevant for broad classes of stochastic models and demonstrates the need in advancing the theory of stochastic processes.

scholarly journals Sub-microstructures of Nephrite from Five Sources Based on Multispectral Imaging and Effect Enhancement

2020 ◽  
pp. 13-24
Author(s):  
Dian Chen ◽  
Ming Yu ◽  
Wugan Luo ◽  
Changsui Wang
Keyword(s):  
Size Distribution ◽  
Multispectral Imaging ◽  
The Body ◽  
Future Research ◽  
Strong Light ◽  
Visual Effect ◽  
Naked Eye ◽  
Set Up ◽  
Different Sources ◽  
Microstructure Imaging

Some collectors and connoisseurs have found that the nephrite from different sources possess different sub-microstructures inside the body, which could become a quite convenient and effective basis for determining provenance. The sub-microstructure of nephrite can be observed by the naked eye under irradiated by strong light. However, the images of original submicrostructure of nephrite were recorded by use of multispectral imaging in our previous work, but the visual effect is not satisfied. Here, the main features of different sub-microstructures will present more distinct by appropriately subtracting the shining strength and then the average filtering is adopted to promote the resolution of sub-microstructure imaging as well as to reduce some image noises. The sub-microstructure images of nephrite from five most common sources have typical inherent characteristics respectively, which are qualified to set up a demonstration for identifying provenances. Furthermore, the shape, size, distribution and name for these different sub-microstructures have been summarized and they will become the basis for future research on the provenance of nephrite including the ancient jade.

scholarly journals A new experimental approach to study the hygroscopic and optical properties of aerosols: application to ammonium sulfate particles

2014 ◽  
Vol 7 (1) ◽  
pp. 183-197 ◽  
Author(s):  
C. Denjean ◽  
P. Formenti ◽  
B. Picquet-Varrault ◽  
Y. Katrib ◽  
E. Pangui ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Size Distribution ◽  
Ammonium Sulfate ◽  
Residence Time ◽  
Mie Scattering ◽  
Continuous Increase ◽  
Continuous Growth ◽  
Hygroscopic Properties

Abstract. A new methodology for the determination of the changes due to hygroscopic growth with relative humidity of the number size distribution and optical properties of polydispersed aerosols is described. This method uses the simulation chamber CESAM where the hygroscopic properties of polydispersed aerosol particles can be investigated in situ by exposing them to RH ranging from 0 to 100% for approximately 1 h. In situ humidification is used to provide simultaneous information on the RH-dependence of the particle size and the corresponding scattering coefficient (σscat), and that for the entire size distribution. Optical closure studies, based on integrated nephelometer and aethalometer measurements, Mie scattering calculations and measured particle size distributions, can therefore be performed to yield derived parameters such as the complex refractive index (CRI) at λ = 525 nm. The CRI can also be retrieved in the visible spectrum by combining differential mobility analyzer (DMA) and white light aerosol spectrometer (Palas Welas®) measurements. We have applied this methodology to ammonium sulfate particles, which have well known optical and hygroscopic properties. The CRI obtained from the two methods (1.54–1.57) compared favourably to each other and are also in reasonable agreement with the literature values. The particle's growth was compared to values obtained for one selected size of particles (150 nm) with a H-TDMA and the effect of the residence time for particles humidification was investigated. When the humidification was performed in the chamber for a few minutes, a continuous increase of the ammonium sulfate particle's size and σscat was observed from RH values as low as 30% RH. Comparison of the measured and modelled values based on Köhler and Mie theories shows that layers of water are adsorbed on ammonium sulfate particles below the deliquescence point. In contradiction, the particle's growth reported with H-TDMAs showed a prompt deliquescence of ammonium sulfate particles with no continuous growth in size at low RH. These findings highlight the need to allow sufficient time for particle-water vapour equilibrium in investigating the aerosols hygroscopic properties. H-TDMA instruments induce limited residence time for humidification and seem to be insufficient for water adsorption on ammonium sulfate particles.

The Properties of Asperities of Real Surfaces

2000 ◽  
Vol 123 (4) ◽  
pp. 872-883 ◽  
Author(s):  
Jiunn-Jong Wu
Keyword(s):  
Correlation Function ◽  
Size Distribution ◽  
Root Mean Square ◽  
Contact Model ◽  
Mean Square ◽  
Auto Correlation ◽  
Auto Correlation Function

The properties of asperities are investigated. It is found that the asperity size distribution of asperities can be estimated by the auto-correlation function. New definitions for asperity and asperity curvature are employed. It is found that asperity curvature can be estimated by root mean square curvature of profile. With the finding of this paper, the statistical contact model can be used more accurately.

scholarly journals Size distribution and ionic composition of marine summer aerosol at the continental Antarctic site Kohnen

2017 ◽  
Author(s):  
Rolf Weller ◽  
Michel Legrand ◽  
Susanne Preunkert
Keyword(s):  
Size Distribution ◽  
Marine Boundary Layer ◽  
Ionic Composition ◽  
Austral Summer ◽  
Weddell Sea ◽  
Aerosol Sampling ◽  
Pressure System ◽  
Continuous Growth ◽  
Clear Sky ◽  
Sky Conditions

Abstract. We measured aerosol size distributions and conducted bulk as well as size segregated aerosol sampling during two summer campaigns in January 2015 and January 2016 at the continental Antarctic station Kohnen (Dronning Maud Land). Physical and chemical aerosol properties differ conspicuously during the episodic impact of an outstanding low pressure system in 2015 (LPS15) compared to the prevailing clear sky conditions: The about three days persisting LPS15, located in the eastern Weddell Sea, was associated with marine boundary layer air mass intrusion, enhanced condensation particle concentrations (1400±700 cm−3 compared to 250±120 cm−3 under clear sky conditions; mean ± SD), occurrence of a new particle formation event exhibiting a continuous growth of particle diameters (Dp) from 12 nm to 43 nm over 44 hours (growth rate 0.6 nm h−1), peaking methane sulfonate (MS−), non-sea salt sulfate (nss-SO42−) and Na+ concentrations (190 ng m−3 MS−, 137 ng m−3 nss-SO42−, and 53 ng m−3 Na+ compared to 24±15 ng m−3, 107±20 ng m−3 and 4.1±2.2 ng m−3, respectively, during clear sky conditions, and finally an increased MS-/nss-SO42− mass ratio ßMS of 0.4 up to 2.3 (0.21±0.1 under clear sky conditions) comparable to typical values found at coastal Antarctic sites. Throughout the observation period a larger part of MS− could be found in super micron aerosol compared to nss-SO42−, i.e. (10±2) % by mass compared to (3.2±2) %, respectively. On the whole, under clear sky conditions aged aerosol characterized by an usually mono-modal size distribution around Dp = 60 nm was observed. Although our observations indicate that sporadic impacts of coastal cyclones were associated with enhanced marine aerosol entry, at large aerosol deposition on-site during austral summer should be dominated by the typical steady clear sky conditions.

scholarly journals The chemical composition and age of monazite and kularite from titanium ore of Pizhemskoye and Yarega deposits (Middle and Southern Timan)

Georesursy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 22-31
Author(s):  
Alexander B. Makeyev ◽  
Sergey E. Borisovsky ◽  
Anna O. Krasotkina
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Species Composition ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Hydrothermal Conversion ◽  
Granite Batholith ◽  
Weathering Crusts ◽  
Different Sources

A study on the typomorphic characteristics and age of the monazite the two giant titanium deposits of the Timan – Pizhemskoye and Yarega, which revealed differences in morphology in the species composition of the inclusions, the grain size, distribution of chemical types of a mineral associated with conditions of crystallization and different sources of the substance. The isochronous Th-Pb monazite age was calculated using the «CHIME» method. For Yarega monazite built three isochrone with age 1301, 1105 and 778 Ma; for Pizhemsky monazite-kularite one isochrone with age 782 Ma. Source of hith-Th monazite Yarega oil-titanium deposit could be ancient granite batholith and the origin Yarega less-Th monazite and Nd-Ce-monazite-kularite Pizhemskoye deposit with an age of ~ 780 Ma could be related to the hydrothermal conversion of the weathering crusts on lamprophyres close in age with lamprophyre (spessartite and kersantite) of Chetlassky Kamen.

scholarly journals Detailed Fluctuation Theorems: A Unifying Perspective

Entropy ◽  
2018 ◽  
Vol 20 (9) ◽  
pp. 635 ◽  
Author(s):  
Riccardo Rao ◽  
Massimiliano Esposito
Keyword(s):  
Arbitrary Number ◽  
Stochastic Dynamics ◽  
Fluctuation Theorem ◽  
Jump Processes ◽  
Markovian Jump ◽  
Stochastic Thermodynamics ◽  
Fluctuation Theorems ◽  
Thermodynamic Structure ◽  
General Method

We present a general method to identify an arbitrary number of fluctuating quantities which satisfy a detailed fluctuation theorem for all times within the framework of time-inhomogeneous Markovian jump processes. In doing so, we provide a unified perspective on many fluctuation theorems derived in the literature. By complementing the stochastic dynamics with a thermodynamic structure (i.e., using stochastic thermodynamics), we also express these fluctuating quantities in terms of physical observables.

Evaluation of Sand Quality and its Effect on Mortar and Cement Concrete

2020 ◽  
Vol 8 (2) ◽  
pp. 62-68
Author(s):  
H. Laldintluanga ◽  
◽  
Rebecca Ramhmachhuani ◽  
Ram thlengliani
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Clay Content ◽  
Raw Material ◽  
Fine Aggregate ◽  
River Sand ◽  
Proctor Test ◽  
Additional Water ◽  
Different Sources

The most used raw material in concrete are cement, sand and coarse aggregate. The study involved performing a series of tests on river sand and crushed sand that was collected from different sources to find the feasibility of commonly used sand in Mizoram. The properties of sand have been checked in terms of particle size distribution, fineness modulus, specific gravity. The effect of different sources of sand which are having different properties in mortar and concrete has been investigated. The sand was collected from different source having different particle size distribution as well as different silt and clay content. The quantity of water calculated based on normal consistency value cannot be applied to mortar which has sand having cohesion. Optimum moisture content calculated using the Standard Proctor test for cohesive sand is used to find out the additional water required on the mortar mix. The mortar with an exact amount of water has higher strength and density. The bonding is weakened in strength by non- binding material like silt and clay. Test results show that a decrease in compressive strength when the ratio of silt content to fine aggregate increase. It is found out that there is a large variation in the strength of mortar and concrete due to variation in the quality of sand use.

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