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Optimal control strategies for tuberculosis treatment: a case study in Angola

We apply optimal control theory to a tuberculosis model given by a system of ordinary differential equations. Optimal control strategies are proposed to minimize the cost of interventions. Numerical simulations are given using data from Angola.

Functionalization of CNTS with maleic anhydride

The outstanding properties of carbon nanotubes (CNTs) [1] are mainly related with their unique structural features. However, the high π-π staking between the tubes is a major drawback for their manipulation and interaction with other materials. Chemical functionalization has been used as a convenient tool to improve their performance in various applications [2]. The work reports the functionalization of multi-...

Intracerebral amyloidoma: imaging findings might support preoperative diagnosis

The diels-alder cycloaddition reaction of 1,3-butadiene to MWCNTs

In this study the funtionalization of MWCNTs with 1,3-butadiene generated in situ from solfolene was investigated. The reaction was studded at two different temperatures (100ºC and 150ºC), mass ratios (CNTs:Sulfolene of 1:1 and 1:2) and different time reaction (2, 4 and 7 days). Thermogravimetric analysis (TGA) showed high degree of functionalization in a range of 10 % to 23 % in weight loss at 800 ºC. The acid...

Ocorrência de ferrugem no Pinhão-manso, em Mato Grosso do Sul, e efeito de algu...

2008 ; Documento on-line.

Wang-Landau sampling in three-dimensional polymers

Monte Carlo simulations using Wang-Landau sampling are performed to study three-dimensional chains of homopolymers on a lattice. We confirm the accuracy of the method by calculating the thermodynamic properties of this system. Our results are in good agreement with those obtained using Metropolis importance sampling. This algorithm enables one to accurately simulate the usually hardly accessible low-temperature...

Two-dimensional Newton's problem of minimal resistance

Newton's problem of minimal resistance is one of the first problems of optimal control: it was proposed, and its solution given, by Isaac Newton in his masterful Principia Mathematica, in 1686. The problem consists of determining, in dimension three, the shape of an axis-symmetric body, with assigned radius and height, which offers minimum resistance when it is moving in a resistant medium. The problem has a ve...

Incorporation of CdS nonoparticles from colloidal solution into optically clear...

Nanocomposite materials based on an organic-inorganic ureasilicate matrix with embedded CdS nanoparticles were produced and characterized by optical (UV/Vis), FTIR, secondary ion mass spectroscopy, inductively-coupled plasma optical emission and steady-state photoluminescence measurements. The ureasilicate precursor was obtained by the reaction between silicon alkoxyde modified by isocyanate groups and polyethy...

Effect of concentration of the diazoalcene molybdenum complex immobilized in ur...

The complex trans-[FMo(NNCHCHCHCH2CH3)(Ph2PCH2CH2PPh2)2][BPh4], was dispersed in a hybrid matrix synthesized by a sol-gel process. The host matrix of the so-called ureasil is a network of silica to which oligopolyoxyethylene chains [POE, (OCH2CH2)n] are grafted by means of urea cross-links. The free complex and sol-gel materials were characterized by thermal analysis (DSC), surface analysis (XPS) and spectrosco...

Synthesis and characterization of a sol-gel derived ureasilicate hybrid organic...

A hybrid organic-inorganic material filled with in situ generated inorganic particles has been synthesised by the homogeneous precipitation of CdS from aqueous solutions of Cd(NO3)2 and CH3CSNH2 . These highly transparent, homogeneous and flexible CdS doped xerogels were prepared by the sol-gel technique using, as precursors, organically modified silicon alkoxide (3-isocyanatepropyltriethoxysilane) and a di-ami...