Sharif Digital Repository

This paper deals with estimation of fractional order and pole locator in fractional order systems. The estimation is based on Bode diagram of the system that is obtained using input and output measurements. Here the magnitude diagram is approximated with number of straight lines depending on the level of complexity and in consequence a very good estimation of fractional order and acceptable approximations of pole locators are determined. Relying on the proposed method, complexity of fractional order system identification which is mostly due to the estimation of fractional order is substantially resolved. Some example simulation results are provided to explain the work and show its... 

This paper deals with the identification of fractional-order systems through orthogonal rational functions. Fractional systems are characterized by their non-exponential aperiodic multimodes; therefore, fractional orthogonal rational functions provide better approximating models with fewer parameters. In spite of the fact that the Laguerre-based model is simple, it is, to some extent, deficient at high frequencies. Motivated by this objective, the use of a Legendre basis which has progressive pole locations and can be expected to perform better at high frequencies is studied  

In this report, the synthesis of a new bi-macrocycle tweezer linked through an azobenzene moiety, L was undertaken. The characterization of the tweezer was accomplished by employing IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy and CHN microanalysis while the UV–visible spectroscopy illustrated a trans ⇆ cis photo-isomerization for L. According to our preliminary fluorescence observations, a metal-ion chemosensing behavior was established for trans-L isomer towards Cr(III) ion among the library metal ions. The quenching of the respective trans ⇆ cis isomerization in the presence of Cr(III) ion suggested the preference of a strong interaction between Cr(III) ion with L, leading to... 

In the present research, a new tweezer T bearing azobenzene linker 1 was prepared, characterized by applying FT-IR spectroscopy, fluorescence spectroscopy, UV–visible spectroscopy, and elemental analysis 1H and 13C{1H} NMR. T crystals were obtained by reaction of 1 with ZnTPP in CHCl3/acetone. Under irradiation with a mercury lamp to achieve the trans-to-cis isomerization, a dramatic color change from violet to green in chloroform was observed. The X-ray crystallography of T revealed an observable macroring deformation of the ZnTPP for the trans isomer. We observed a deviation of 0.11 Å from planarity for the least-squares plane of ZnTPP owing to the axial coordination by the pyridine... 

The interaction of [60]fullerene with a series of 15-19-membered macrocycles containing an O 2N 2-donor set has been investigated by UV-visible spectroscopy. The formation constants arising from the complexation of [60]fullerene with these azacrown macrocycles, having various ring size, were determined in CHCl 3 media applying Benesi-Hildebrand equation. The stoichiometry has been found by the Job method in each case. The thermodynamic parameters, for example, formation enthalpies (δH o) and entropies (δS o), for these complexation were also determined. Experimentally, it was found that macroring size of the azacrown has a prominent effect on azacrown complexation with [60]fullerene in terms... 

To find metal ion recognition by L (L = O2N2-donor naphthodiaza-crown macrocyclic ligand), the complexes [ML]2+ (M = Cd, Hg and Pb) were synthesized and characterized by IR, 1H, 13C NMR, and mass spectrometry, as well as elemental microanalysis. Hg(II) showed perceptible enhancement of the fluorescence of L in which ultra-low limit of detection for Hg(II) by L was determined as 1 nM in ethanol and DMSO. L reserved selectivity of Hg(II) in its binary mixtures with metal cations in solution. A 1 : 1 stoichiometry was found for the interaction of Hg(II) with L while Benesi–Hildebrand method was applied to calculate its complexation binding constant (K BH) employing fluorescence... 

A series of N2O2-donor naphthodiaza-crown macrocyclic ligands, L1-L5, were synthesized and characterized by IR, 1H and 13C NMR spectroscopy, mass spectrometry as well as microanalysis. Preliminary observations employing UV-vis spectrophotometry of L3 in ethanol revealed that triethylamine (TEA) has a significant blue-shift effect on the entire of the spectra. Then, the detection of aliphatic and aromatic amines by L3 were followed by monitoring of fluorescence quenching of the resulting adducts in terms of their binding with L1-L5. Both steady-state and time-resolved spectroscopic measurements in the... 

Supramolecular complexation of C60 with L1-L5 were studied in toluene, chloroform and 1,2-dichlorobenzene solvents using UV–vis, fluorescence, 1H, 13C NMR spectroscopy as well as density functional theory (DFT) calculations. The Job’s plot of continuous variation method established 1:1 stoichiometry for L1-L5/C60. Binding constants (K) calculated for L1-L5/C60 were also determined employing UV–vis and fluorescence spectroscopy. Both steady-state and time-resolved fluorescence spectroscopic surveys showed remarkable fluorescence quenching phenomenon for L1-L5 in the presence of C60 which was primarily attributed to involvement of a static process. The observed fluorescence quenching in L1–L5... 

The noticeable enhancement in fluorescence emission of O2N2-donor naphthodiaza-crown macrocyclic ligand (L) in the presence of Hg2+ was observed in which the fluorescence quantum yield of free ligand L as well as L/Hg2+ complex were found to be as 0.29 and 0.49, respectively. The observed ultra-low limit of detection (LOD) for Hg2+ by L was determined as low as 1.0 × 10−11 M in water. A 1:1 stoichiometry was also established for L/Hg2+ together with a binding constant KBH = 66,543 by employing fluorescence spectrophotometry. The competition experiments on L/Hg2+ demonstrated highly selective detection of Hg2+ in the presence of the library cations. A two path mechanism for detection of metal... 

Two new macrocyclic ligands Ln (L and L′) bearing two fluorophore naphthalene moieties were synthesized and characterized by employing 1H and 13C NMR, IR, microanalysis as well as mass spectrometry. Comparative studies on the effect of assorted metal cations as Cr(III), Cu(II), Zn(II), Cd(II), Pb(II), Na(I), Ni(II), Co(II), Ba(II), Fe(II), Al(III), Mg(II), Cs(I), Ca(II), Hg(II), K(I), Mn(II), Ag(I), Fe(III) on fluorescence and UV–vis spectra of Ln in ethanol illustrated that both of the macrocycles were sensitive and selective fluorescence chemosensors for Al(III). Remarkable binding constant values as 1.36 × 105 M−1 and 1.15 × 105 M−1 alongside 1:1 stoichiometry for Al(III)/L and Al(III)/L′... 

Two new macrocyclic ligands Ln (L and L′) bearing two fluorophore naphthalene moieties were synthesized and characterized by employing 1H and 13C NMR, IR, microanalysis as well as mass spectrometry. Comparative studies on the effect of assorted metal cations as Cr(III), Cu(II), Zn(II), Cd(II), Pb(II), Na(I), Ni(II), Co(II), Ba(II), Fe(II), Al(III), Mg(II), Cs(I), Ca(II), Hg(II), K(I), Mn(II), Ag(I), Fe(III) on fluorescence and UV–vis spectra of Ln in ethanol illustrated that both of the macrocycles were sensitive and selective fluorescence chemosensors for Al(III). Remarkable binding constant values as 1.36 × 105 M−1 and 1.15 × 105 M−1 alongside 1:1 stoichiometry for Al(III)/L and Al(III)/L′... 

Sleep Spindle is the hallmark of the second stage of sleep in EEG signal. It had been analyzed using different methods, including Fourier transform, parametric and non-parametric models, higher order statistics and spectra, and also time-frequency methods such as wavelet transform, and matching pursuit. In this study, bump modeling has been used to analyze sleep spindle. Bump modeling is a method which represents the time-frequency map of signals with a number of elementary functions. Results of this work demonstrate that bump modeling is capable of analyzing different sleep spindle patterns in sleep EEG signals successfully  

Fluorescence spectroscopy of a series of N2O2-donor naphthodiaza-crown macrocyclic ligands, L1-L4 , in ethanol revealed that Cu(II) cation had remarkable fluorescence quenching effect during complex formation with L2 and L3 , while Zn(II) displayed noticeable enhancement on the fluorescence emission of L1 and L4 , respectively. Fluorescence quantum yields of Ln (L1-L4 ) as well as their complexes Ln /M (II) (M=Cu, and Zn) were found as 0.11-0.34, respectively. The complementary experiments on determination of the limit of detection indicated (LOD) that L2 and L3 were highly selective for detection of Cu(II) while L1 and L4 were selective towards Zn(II), respectively. Using Benesi-Hildebrand... 

Fluorescence spectroscopy of a series of N2O2-donor naphthodiaza-crown macrocyclic ligands, L1-L4, in ethanol revealed that Cu(II) cation had remarkable fluorescence quenching effect during complex formation with L2 and L3, while Zn(II) displayed noticeable enhancement on the fluorescence emission of L1 and L4, respectively. Fluorescence quantum yields of Ln (L1-L4) as well as their complexes Ln/M (II) (M = Cu, and Zn) were found as 0.11–0.34, respectively. The complementary experiments on determination of the limit of detection indicated (LOD) that L2 and L3 were highly selective for detection of Cu(II) while L1 and L4 were selective towards Zn(II), respectively. Using Benesi–Hildebrand... 

Let G be a graph. The minimum number of colors needed to color the edges of G is called the chromatic index of G and is denoted by x0(G). It is well known that δ(G) ≤ x0(G) ≤ δ(G) + 1, for any graph G, whereδ(G) denotes the maximum degree of G. A graph G is said to be class 1 if x0(G) = δ(G) and class 2 if x0(G) = δ(G)+1. Also, Gδ is the induced subgraph on all vertices of degreeδ(G). Let f : V(G) ! N be a function. An f -coloring of a graph G is a coloring of the edges of E(G) such that each color appears at each vertex v 2 V(G) at most f (v) times. The minimum number of colors needed to f -color G is called the f -chromatic index of G and is denoted by x0f (G). It was shown that for every... 

In the present communication, three bimacrocyclic tweezers linked through azobenzene moiety, Ln (n = 1–3) were synthesized in a multistep route and characterized by x-ray crystallography, IR, 1H and 13C NMR, UV–vis spectroscopy as well as CHN microanalysis. UV–visible spectroscopy established that the irradiation of L1 and L3 with UV light promoted the trans to cis isomerization. Irradiating the reaction mixtures with Hg lamp, significant supramolecular interactions between L1 and L3 with C60 were also found in terms of the association constants calculated by UV–visible spectroscopy, denoting on more pronounced interaction with C60 that in the absence of UV light. The molecular structures of... 

Let G be a graph and f: V (G) → ℕ be a function. An f-coloring of a graph G is an edge coloring such that each color appears at each vertex v ∈ V (G) at most f(v) times. The minimum number of colors needed to f-color G is called the f-chromatic index of G and is denoted by χʹf(G). It was shown that for every graph G, Δf(G) ≤ χʹf(G) ≤ Δf(G) + 1, where Δf(G) = maxv ∈V (G)(formula presented). A graph G is said to be f-Class 1 if χʹf(G) = Δf(G), and f-Class 2, otherwise. Also, GΔfis the induced subgraph of G on (formula presented). In this paper, we show that if G is a connected graph with Δ(GΔf) ≤ 2 and G has an edge cut of size at most Δf(G) − 2 which is a star, then G is f-Class 1. Also, we... 

A proper vertex coloring of a graph G is called a star coloring if every two color classes induce a forest whose each component is a star, which means there is no bicolored P4 in G. In this paper, we show that the Cartesian product of any two cycles, except C3C3 and C3C5, has a 5-star coloring. © 2022 World Scientific Publishing Company  

A simple method for the formation of inclusion complex of [60]fullerene with two O2N2-donor aza-crown macrocyclic ligands was introduced. The products were characterized using UV-vis and IR spectroscopies as well as HPLC, and ESI mass spectrometry. The ESI mass and elemental analysis data revealed that the ratio of macroring:[60]fullerene were not the same. The binding capability of the macrorings as well as the number of the macroring addends to [60]fullerene were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Considering percentage mass loss in different steps of TG and the enthalpy changes in DSC found for each of these products, the number... 

Purpose: The purpose of this paper is to describe the use of computational fluid dynamics (CFD) to simulate indoor radon distribution and ventilation effects. This technique was used to predict and visualize radon content and indoor air quality in a one-family detached house in Stockholm. The effects of intake fans, exhaust fans and doors on radon concentration were investigated. Design/methodology/approach: In this study a mechanically balanced ventilation system and a continuous radon monitor (CRM) were used to measure the indoor ventilation rate and radon levels. In a numerical approach, the FLUENT CFD package was used to simulate radon entry into the building and ventilation effects....