Instituto Tecnológico de Morelia

About: Instituto Tecnológico de Morelia is a education organization based out in Morelia, Mexico. It is known for research contribution in the topics: Electric power system & AC power. The organization has 498 authors who have published 572 publications receiving 4600 citations.

Synthesis of carbon nanomaterials by chemical vapor deposition method using green chemistry principles

Abstract: Environmentally friendly synthetic methodologies have gradually been implemented as viable techniques in the synthesis of a range of nanostructures. This book chapter focuses on the application of green-chemistry principles to the synthesis of various carbon nanomaterials. In particular, we describe the chemical vapor deposition, an environmentally friendly, simple, and mainly one-step process technique. Special attention is given to the development of emerging nanostructures; such obtained from environmental care precursors as well as reutilized materials. These research studies involved natural ingredients to synthesize nanomaterials and design environmentally benign methodologies that allows carbon nanostructures production without the need to sacrifice sample quality, purity and crystallinity; the control over size, shape and morphology remain.

Electrical conductivity and Vickers microhardness of composites synthesized from multiwalled carbon nanotubes and carbon spheres with poly(methyl methacrylate): a comparative study

Abstract: Since the discovery of carbon nanotubes, they have been intensely studied as filler materials into different matrices, including polymers to obtaining composites with enhancing properties. Carbon spheres are other type of nanostructures that have not been enough studied as reinforcement material. Polymeric composites with enhanced properties have gradually replaced many of the conventional materials in several areas. In this research, a comparative study of composites based in MWCNTs and CSs incorporated in poly(methyl methacrylate) matrices by mixing solution method was carried out. Composites with 2 wt%, 3 wt%, and 4 wt% of MWCNTs and CSs were obtained through solution mixing and were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Carbon sphere composites were observed with better dispersion than carbon nanotube composites through SEM. D, G, and G’ characteristic bands of carbon nanostructures and typical bands of PMMA were observed by Raman spectroscopy in all composites. C–H, C=O, and CH2 vibrations were depicted in composites spectra by FTIR. Vickers microhardness and electrical conductivity of composites were measured. A significant increasing in electrical conductivity was obtained in MWCNTs/PMMA composites, reaching values up to 8.45 × 10–5 S/cm. Nevertheless, the highest electrical conductivity values were observed in CSs composites (7.98 × 10–4 S/cm). Vickers microhardness also was enhanced in all composites; however, CSs/PMMA composites showed the highest values in contrast with MWCNTs/PMMA composites. The major Vickers and electrical conductivity properties of CSs/PMMA composites are attributed to better carbon spheres dispersion into polymer matrix.

Perturbative method for maximum likelihood estimation of the Weibull distribution parameters

Abstract: The two-parameter Weibull distribution is the predominant distribution in reliability and lifetime data analysis. The classical approach for estimating the scale [Formula: see text] and shape [Formula: see text] parameters employs the maximum likelihood estimation (MLE) method. However, most MLE based-methods resort to numerical or graphical techniques due to the lack of closed-form expressions for the Weibull [Formula: see text] parameter. A Weibull [Formula: see text] parameter estimator based on perturbation theory is proposed in this work. An explicit expression for [Formula: see text] is obtained, making the estimation of both parameters straightforward. Several right-censored lifetime data sets with different sample sizes and censoring percentages were analyzed in order to assess the performance of the proposed estimator. Study case results show that our parameter estimator provides solutions of high accuracy, overpassing limitations of other parameter estimators.

Stress Corrosion Cracking Behavior of X60 Pipe Steel in Soil Environment

Abstract: Stress corrosion cracking (SCC) susceptibility of API X60 pipeline steel in a soil solution by slow strain rate tests (SSRT), and surface fracture analysis was investigated. The SSRT were performed at strain rate of 25.4 × 10-6 mm/sec in a glass autoclave containing the soil solution called NS4 with pH of 3 and 10 at room temperature and 50°C. Both anodic and cathodic polarization potentials of 200 mV referred to Ecorr was applied. The results of ratio reduction area (RRA), time to failure ratio (TFR) and elongation plastic ratio (EPR) indicate that X60 pipeline steel was susceptible to SCC at pH 3 and cathodic polarization of -200 mV at room temperature and 50°C. Scanning electron microscopy (SEM) observations of these specimens showed a brittle type of fracture with transgranular appearance. The SCC process and mechanism of X60 steel into NS4 solution was hydrogen based mechanism. With the different applied potentials the dominance of SCC process changes. At low pH the temperature effect on SCC susceptibility is more noticeable at 20°C. However at high pH this effects changes, being the steel more susceptible to SCC at 50°C.

Non-Invasive Glucose Measurement Using Spectrography In Near Infrared (NIR)

Abstract: Diabetes mellitus is a health problem that affects approximately one in eight people worldwide, without an adequate control of the disease, it can lead to various medical complications ranged from blindness to limbs amputation. There are different methods for measuring blood glucose classified as invasive and non-invasive. Invasive methods require a small drop of blood to deliver results. Although the test is quick and simple, making daily punctures on patient’s skin can be painful and traumatizing, especially in child patients. Besides, using lancets increases the risk of diseases transmission as well as infections. This paper presents a system to detect blood glucose levels using a non-invasive method, based on 1550 nm infrared spectroscopy, moreover, accuracy is improved by taking into account the estimation of skin characteristics such as color and thickness obtained with a green-light based method. Experimental results show that the proposed methodology is suitable for non-invasive blood glucose measurement in a controlled environment.