Determination of the optimized single-layer ionospheric height for electron content measurements over China

2017 ◽  
Vol 92 (2) ◽  
pp. 169-183 ◽  
Author(s):  
Min Li ◽  
Yunbin Yuan ◽  
Baocheng Zhang ◽  
Ningbo Wang ◽  
Zishen Li ◽  
...  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Silvia Zaoli ◽  
Piero Mazzarisi ◽  
Fabrizio Lillo

AbstractBetweenness centrality quantifies the importance of a vertex for the information flow in a network. The standard betweenness centrality applies to static single-layer networks, but many real world networks are both dynamic and made of several layers. We propose a definition of betweenness centrality for temporal multiplexes. This definition accounts for the topological and temporal structure and for the duration of paths in the determination of the shortest paths. We propose an algorithm to compute the new metric using a mapping to a static graph. We apply the metric to a dataset of $$\sim 20$$ ∼ 20 k European flights and compare the results with those obtained with static or single-layer metrics. The differences in the airports rankings highlight the importance of considering the temporal multiplex structure and an appropriate distance metric.


As an introduction to the study of reactions contingent on ionization in flames, an experimental measurement has been made of the collision frequency of electrons with molecules in coal-gas/air flames, containing added alkali metal salt. This quantity is an important parameter in the expression relating the electron content of a flame with the attenuation of centimetric radio waves by it. This attenuation has been chosen as a convenient method of investigating flame ionization. The form of the results obtained agree well with the predictions of theory, a uniform difference of about 20 % between measured collision frequency and that calculated on a very simple gas kinetic hypothesis being obtained. A suitable conversion factor has been evolved for proceeding from attenuation of 3 cm. waves to electron concentration/cm. 3 .


2012 ◽  
Vol 2 (1) ◽  
Author(s):  
R. Angelova

AbstractThe paper presents an experimental procedure developed for determination of the pore size, shape and distribution in a single layer woven fabric, for the construction of a virtual model to be incorporated in a future CFD software package. The procedure is based on non-destructive observation and analysis of woven samples. 14 different samples of gray fabrics of 100 % cotton in plain and twill weaves are investigated. The results obtained allow the creation of reality more realistic virtual model of the woven structure, and theoretical investigation of its porosity and permeability through computer simulation.


Author(s):  
Vitaly Zholtikov ◽  
Vladimir Golovatinskii ◽  
Riadh Ouerghi ◽  
Rollin K Daniel

Abstract Background Camouflage of nasal dorsum, aesthetic augmentation and highlighting the dorsal aesthetic lines are essential elements in modern rhinoplasty. Numerous techniques have been utilized including deep temporal fascia, rectus abdominis fascia, and diced cartilage in fascia (DC-F). Despite their wide spread adoption, technical challenges remained, especially when utilized for aesthetic purposes. Objectives The paper details the use of fascia (F) and diced cartilage in fascia grafts (DC-F) for aesthetic dorsal refinement in primary and secondary cases. One of the main goals was to achieve ideal dorsal aesthetic dorsal lines rather than just volume augmentation. Methods We used grafts from the deep temporalis fascia (F) and rectus abdominis fascia (RF) in 4 configurations: 1) single layer, 2) double layer, 3) full length diced cartilage in fascia grafts (DC-F), and 4) partially filled – segmental DC-F grafts. Technical refinements included careful determination of dimensions and meticulously suturing to the dorsum at appropriately 10 points to prevent graft displacement. Results We report our experience: 146 clinical cases over 35 months from January 2017 to December 2019. The patients were divided for 4 groups depending on which type of graft was used. Conclusions Use of autogenous deep temporal fascia, rectus abdominis fascia, and diced cartilage in fascia (DC-F) to camouflage dorsal irregularities, to highlight dorsal aesthetic lines, and to aesthetically augment either the entire nasal dorsum or its individual parts. Optimization of cutting, stitching, filling the graft, careful fixation of these grafts on the nasal dorsum, significantly increases the predictability of these techniques and minimizes problems.


2020 ◽  
Vol 42 (6) ◽  
pp. 856-856
Author(s):  
Sehrish Qazi Sehrish Qazi ◽  
Huma Shaikh Huma Shaikh ◽  
Ayaz Ali Memon Ayaz Ali Memon ◽  
and Shahabuddin Memon and Shahabuddin Memon

Among all psychotropic alkaloids, nicotine is more addictive, carcinogenic and capable of causing many health problems. This work is based on the development of highly robust, cheap, reliable, selective and sensitive nicotine imprinted graphene oxide nanocomposite (ImpGO nanocomposite) based optical sensor for determination of nicotine in human plasma. The ImpGO nanocomposite has been thoroughly characterized using different techniques i.e. FT-IR, SEM, TEM, Raman, etc. These characterizations revealed that ImpGO nanocomposite is comprised of single layer of graphene oxide successfully modified with imprinted polymer. The synthesized material was utilized to selectively determine nicotine using UV-vis spectrophotometer in BR buffer of 0.1 M at pH 3 and diluted human plasma. The effect of parameters such as buffer concentration, pH, amount of nanocomposite, etc on determination of nicotine using ImpGO nanocomposite were studied thoroughly. Thus, a sensitive optical method was developed for determination of nicotine in human plasma with linear range of 22-370 pM along with LOD and LOQ of 7 pM and 22 pM, respectively. The selectivity of sensor was evaluated using homologues of nicotine such as nicotine amide, caffeine and cotinine. The results obtained from biological samples showed that developed optical sensor is efficient in complex matrices of real sample.


2010 ◽  
Vol 165 ◽  
pp. 110-117
Author(s):  
Jerzy Łabanowski ◽  
J. Ćwiek

Degradation examinations of outer surface of low-emission steam boiler evaporator tubes are presented in the paper. Metallographic evaluation of scale morphology as well as determination of chemical composition of micro sites and distribution of elements on cross-sections is reported. Water-wall tubes were exposed in steam boiler for up to two years period. Common tubes produced from 16Mo3 steel suffered sulphide and molten salts corrosions. Thermal sprayed tubes with the single layer of 70%Ni 30%Cr alloy demonstrate better corrosion resistance, but become susceptible to sulphide corrosion due to presence of internal voids and cracks. Double layer Al2O3/Ni-30Cr coatings withstood corrosion attack for more than one year of operation, and then failed due to internal heterogeneity and crack generation.


Aerospace ◽  
2005 ◽  
Author(s):  
G. Karami

An equivalent continuum-atomistic algorithm is proposed for carbon-based structures such as nano-scale graphene platelets (NGPs) and carbon nanotubes (CNTs) individually or as stiffeners with polymers. This equivalent continuum-atomistic model will account for the nonlocal effect at the atomistic level and will be a highly accurate mean to determine the bulk properties of graphene-structured materials from its atomistic parameters. In the model, the equivalent continuum and atomic domains are analyzed by finite elements and molecular dynamics finite element-based where atoms stand as nodes in discretized form. Micromechanics idea of representative volume elements (RVE) will be used to determine averaged homogenized properties. In the procedure, a unit hexagonal cell will be the RVE. A minimum volume of material containing this RVE and the neighboring hexagonal cells will be chosen. The size of this volume should cover all the atoms, which have bonded, and nonbonded interaction with the atoms of the RVE unit cell. This minimum volume will be subjected to several load cases. Determination of the response of the RVE hexagonal unit cell contained within the minimum volume, and its potential energy density under the defined load cases, will lead to the determination of mechanical parameters of an equivalent, continuum geometrical shape. For a single layer NGP the thickness of the hexagonal continuum plate is assumed to be 0.34 nm, while in three-dimension and multilayered the actual thickness of layers can be implemented. Under identical loading on the minimum volumes, identical potential (strain) energies for both models will be assumed. Through this equivalence a linkage between the molecular force field constants and the structural elements stiffness properties will be established.


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