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phase-dynamics
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Reconstruction of stochastic dynamical equations: exemplary diffusion, jump-diffusion processes and lévy noise-driven langevin dynamics
, Article Understanding Complex Systems ; 2019 , Pages 227-241 ; 18600832 (ISSN) ; Sharif University of Technology
Springer Verlag
2019
Abstract
In this chapter we reconstruct stochastic dynamical equations with known drift and diffusion coefficients, as well as known properties of jumps, jump amplitude and jump rate from synthetic time series, sampled with time interval τ. The examples have Langevin (white noise- and Lévy noise-driven) and jump-diffusion dynamical equations. We also study the estimation of the Kramers–Moyal coefficients for “phase” dynamics that enable us to investigate the phenomenon of synchronisation in systems with interaction. © 2019, Springer Nature Switzerland AG
Reconstruction of stochastic dynamical equations: exemplary diffusion, jump-diffusion processes and lévy noise-driven langevin dynamics
, Article Understanding Complex Systems ; 2019 , Pages 227-241 ; 18600832 (ISSN) ; Sharif University of Technology
Springer Verlag
2019
Abstract
In this chapter we reconstruct stochastic dynamical equations with known drift and diffusion coefficients, as well as known properties of jumps, jump amplitude and jump rate from synthetic time series, sampled with time interval τ. The examples have Langevin (white noise- and Lévy noise-driven) and jump-diffusion dynamical equations. We also study the estimation of the Kramers–Moyal coefficients for “phase” dynamics that enable us to investigate the phenomenon of synchronisation in systems with interaction. © 2019, Springer Nature Switzerland AG
An Interior Needle Trap by Electropolymerized Pyrrole-based Coating for Headspace Solid-Phase Dynamic Extraction of Chlorobenzenes and Their Determination with Gas Chromatography-Mass Spectrometry
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
Chlorinated benzenes are a group of cyclic aromatic compounds which are used mainly as intermediates in the synthesis of pesticides and other chemicals. These compounds have harmful effects on human health, as on blood, kidneys, skin and eyes, and cause biological disorders and cancers. Chlorobenzenes have been ranked as priority pollutants by the US Environmental Protection Agency (EPA). The permissible level of these compounds for drinking water ranges between 2 μg/L and 1 mg/L. Hence determination of these compounds is of a significant importance. Solid Phase Dynamic Extraction (SPDE) of 5 types of chlorobenzenes (monochlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene,...
Solid-phase Microextraction of BTEXs by Sol-Gel-Based Trimethoxy Silyl Propyl Methacrylate Fiber
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
Conventional solid phase microextraction fibers posses relatively low recommended operating temperature, instability and swelling in organic solvents, breakage of the fiber, stripping of coatings, and bending of the needle. Some of these problems have been obviated by covalent bonding of the polymer phase to the fused-silica substrate by sol-gel technology, but the easy breakage of the fiber still is a remaining challenge In this work, after successful fabrication of unbreakable SPME fibers based on 3-(trimethoxysilyl)propyl methacrylate precursor deposited on the surface of copper wire, the same approach was carried out to synthesis new sol-gel based SPME fibers. Three different coated...
Polymeric Fibers and Sorbents for SPME and In-Needle Device together with GC-MS for Analysis of Environmental Pollutants in Aquatic Media
,
Ph.D. Dissertation
Sharif University of Technology
;
Bagheri, Habib
(Supervisor)
Abstract
Sample preparation gradually becomes a major part of analysis, capable of taking up to 80% of the total time of a complete separation-based analytical process, which typically includes five steps, that is sampling, sample preparation, separation, detection and data analysis. Environmental application is a main cause driving the development of many procedures of sample preparation due to the increased public awareness that environmental contaminants are a health risk. The increased demands in the analysis of foods and natural products have brought another pressure to develop the technologies of sample preparation. The appearance of more sensitive and reliable methodology to monitor...
Trunk coordination in healthy and chronic nonspecific low back pain subjects during repetitive flexion-extension tasks: Effects of movement asymmetry, velocity and load
, Article Human Movement Science ; Volume 45 , 2016 , Pages 182-192 ; 01679457 (ISSN) ; Sanjari, M. A ; Chehrehrazi, M ; Kahrizi, S ; Parnianpour, M ; Sharif University of Technology
Elsevier
Abstract
Multiple joint interactions are critical to produce stable coordinated movements and can be influenced by low back pain and task conditions. Inter-segmental coordination pattern and variability were assessed in subjects with and without chronic nonspecific low back pain (CNSLBP). Kinematic data were collected from 22 CNSLBP and 22 healthy volunteers during repeated trunk flexion-extension in various conditions of symmetry, velocity, and loading; each at two levels. Sagittal plane angular data were time normalized and used to calculate continuous relative phase for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify lumbar-pelvis and...
Comparison of the trunk-pelvis and lower extremities sagittal plane inter-segmental coordination and variability during walking in persons with and without chronic low back pain
, Article Human Movement Science ; Volume 52 , 2017 , Pages 55-66 ; 01679457 (ISSN) ; Kamali, F ; Razeghi, M ; Haghpanah, S. A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Inter-segmental coordination can be influenced by chronic low back pain (CLBP). The sagittal plane lower extremities inter-segmental coordination pattern and variability, in conjunction with the pelvis and trunk, were assessed in subjects with and without non-specific CLBP during free-speed walking. Kinematic data were collected from 10 non-specific CLBP and 10 non-CLBP control volunteers while the subjects were walking at their preferred speed. Sagittal plane time-normalized segmental angles and velocities were used to calculate continuous relative phase for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify the trunk-pelvis and bilateral...
An interior needle electropolymerized pyrrole-based coating for headspace solid-phase dynamic extraction
, Article Analytica Chimica Acta ; Volume 634, Issue 2 , 2009 , Pages 209-214 ; 00032670 (ISSN) ; Babanezhad, E ; Khalilian, F ; Sharif University of Technology
2009
Abstract
A headspace solid-phase dynamic extraction (HS-SPDE) technique was developed by the use of polypyrrole (PPy) sorbent, electropolymerized inside the surface of a needle, as a possible alternative to solid-phase microextraction (SPME). Thermal desorption was subsequently, employed to transfer the extracted analytes into the injection port of a gas chromatography-mass spectrometry (GC-MS). The PPy sorbent including polypyrrole-dodecyl sulfate (PPy-DS) was deposited on the interior surface of a stainless steel needle from the corresponding aqueous electrolyte by applying a constant deposition potential. The homogeneity and the porous surface structure of the coating were examined using the...