Finite‐time stability of linear fractional‐order time‐delay systems

In this paper, a finite‐time stability results of linear delay fractional‐order systems is investigated based on the generalized Gronwall inequality and the Caputo fractional derivative. Sufficient conditions are proposed to the finite‐time stability of the system with the fractional order. Numerical results are given and compared with other published data in the literature to demonstrate the validity of the proposed theoretical results.     

Finite-Time Stability for Caputo–Katugampola Fractional-Order Time-Delayed Neural Networks

Neural Processing Letters - In this paper, an original scheme is presented, in order to study the finite-time stability of the equilibrium point, and to prove its existence and uniqueness, for...     

Solid State Rheological Properties of Ultra‐High Molecular Weight Polyethylene Foams

The rheological properties of ultra‐high‐molecular‐weight polyethylene (UHMWPE) foams were studied using solid state rheometry. Frequency and temperature sweeps were performed in the linear viscoelastic regime. For comparison purposes, low‐density polyethylene (LDPE) and high density polyethylene (HDPE) foams were also studied. For the range of densities under consideration (200‐700 kg/m³), several models for prediction of elastic moduli were compared. It was found that none of the models succeeded in representing completely the mechanical behavior of foams. Further refinements must be made in order to take into account parameters relating the morphology of the foam to its mechanical properties.     

Model‐free kinetics: Curing behavior of phenol formaldehyde resins by differential scanning calorimetry

Isoconversional analysis was used to treat nonisothermal DSC data and yield the dependence of activation energy on conversion during the curing process of PF resins. The shape of the dependence revealed that the curing process of PF resins displayed a change in the reaction mechanism from a kinetic to a diffusion regime. In the kinetic regime a comparative DSC experimental analysis between monomer mixtures and PF resins showed that the addition reactions between phenol and formaldehyde had been mostly completed during the synthesis of PF resins and that the main kinetic reactions contained parallel condensations in the curing process. For the diffusion regime a modified equation for the diffusion rate constant, k_D = D₀ exp(?E_D /RT + K₁α + K₂α²), is proposed. This equation is in good agreement with the experimental dependence of E_α on α in the diffusion regime, which shows the effect of both temperature and conversion on diffusion. A prediction of the conversion advancement with the reaction time under isothermal condition for PF resin has been made. This prediction can be useful in practical applications for evaluating isothermal behavior of thermosetting systems from nonisothermal experimental data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 433–440, 2003     

Poly(arylene ether)s carrying pendant (3‐sulfonated) phenylsulfonyl groups

A series of poly(arylene ether)s with biphenyl units and pendant sulfonated phenylsulfonyl groups was prepared via nucleophilic aromatic substitution reactions of varying ratios of 3,5‐difluoro‐3′‐sulfonated diphenylsulfone and 4,4′‐difluorodiphenylsulfone with 4,4′‐biphenol. As such, the sulfonic acid moieties reside in the meta position of a pendant, electron‐poor phenylsulfonyl group. Mechanically robust proton‐exchange membranes with ion‐exchange capacities (IEC) ranging from 0.91 to 2.05 meq g^?1 were cast from dimethylacetamide. The thermal stability of the membranes was evaluated via thermogravimetric analysis and the 5% weight losses were found to be in excess of 330 °C in air. The glass transition temperatures were determined, via differential scanning calorimetry, to range from a low of 148 to a high of 209 °C at IEC values of 0.91 and 1.79 meq g^?1, respectively. The copolymer membranes reached proton conductivities as high as 142 mS cm^?1 under 100% relative humidity, with relatively low water uptake values (8–32 wt%). Copyright © 2012 Society of Chemical Industry     

β-Selective One-Pot Fluorophosphorylation of d,d-Heptosylglycals Mediated by Selectfluor

This study describes the development of a novel procedure of glycal fluorophosphorylation applied to the synthesis of a fluorinated analogue of an important bacterial metabolite. This procedure was applied to several heptose-derived glycals, and the stereochemical outcome of the reaction was analyzed. Under optimized conditions, the reaction is β-gluco selective, but a significant amount of the α-gluco diastereomer is also generated.     

Global Practical Mittag Leffler Stabilization by Output Feedback for a Class Of Nonlinear Fractional‐Order Systems

In this paper, the problem of a global practical Mittag Leffler feedback stabilization for a class of nonlinear fractional order systems by means of observer is described. The linear matrix inequality approach is used to guarantee the practical stability of the proposed feedback fractional order system. An illustrative example is given to show the applicability of the results.     

Identification of somatostatin receptors using labeled PEGylated octreotide,as an active internalization

Abstract

Numerous normal and tumors cells are well-known to express the somatostatin receptors (SSTRs) on their surface which makes the receptor be useful for tumor scintigraphy. Thus, the identification of SSTRs is beneficial, especially SSTR₂. The somatostatin analog, Octreotide (OCT), was chosen as a ligand, as it is known to selectively bind to SSTR₂. Moreover, polyethylene glycol (PEG), 8armPEG, was used as a branched PEG to provide a low nonspecific cell binding and easily chemical modification. OCT and fluorescein (Flu) were conjugated to branched PEG using a water-soluble carbodiimide (EDC) and N-hydroxy succinimide (NHS) so as to activate its carboxylic acid group. 8armPEG-tagged Flu and OCT was characterized by gel permeation chromatography (GPC) to proof the conjugation of OCT to 8armPEG. Finally, cellular uptake was studied using pancreatic cancer cells with well-expressed somatostatin receptors using a confocal laser scanning microscope (CLMS) and fluorescence activated cell sorting (FACS). GPC showed increases in molecular mass since it showed a difference in elution time of 8armPEG itself and 8armPEG labeled with Flu. CLMS and FACS showed high binding with the positive SSTR₂ cells expression and showed negative results with negative expressing SSTR₂. These bindings were decreased when the receptors were occupied with free OCT which confirms the specific binding to SSTR₂. Therefore, we formulated a novel model to easily identify SSTR₂ and other receptors which serves as a promising platform for identification of tumor cells overexpressing the SSTR₂, which would be a hopeful target for cancer therapy and tumor scintigraphy.     

Assessment of composite beam performance using GWO–ELM metaheuristic algorithm

Composite beams (CBs) include concrete slabs jointed to the steel parts by the shear connectors, which highly popular in modern structures such as high rise buildings and bridges. This study has investigated the structural behavior of simply supported CBs in which a concrete slab is jointed to a steel beam by headed stud shear connector. Determining the behavior of CB through empirical study except its costly process can also lead to inaccurate results. In this case, AI models as metaheuristic algorithms could be effectively used for solving difficult optimization problems, such as Genetic algorithm, Differential evolution, Firefly algorithm, Cuckoo search algorithm, etc. This research has used hybrid Extreme machine learning (ELM)–Grey wolf optimizer (GWO) to determine the general behavior of CB. Two models (ELM and GWO) and a hybrid algorithm (GWO–ELM) were developed and the results were compared through the regression parameters of determination coefficient (R²) and root mean square (RMSE). In testing phase, GWO with the RMSE value of 2.5057 and R² value of 1.2510, ELM with the RMSE value of 4.52 and R² value of 1.927, and GWO–ELM with the RMSE value of 0.9340 and R² value of 0.9504 have demonstrated that the hybrid of GWO–ELM could indicate better performance compared to solo ELM and GWO models. In this case, GWO–ELM could determine the general behavior of CB faster, more accurate and with the least error percentages, so the hybrid of GWO–ELM is more reliable model than ELM and GWO in this study.