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1,171 results on '"Perez, Sergio"'

203. Long-read sequencing uncovers the adaptive topography of a carnivorous plant genome

Author

Lan, Tianying, Renner, Tanya, Ibarra-Laclette, Enrique, Farr, Kimberly M., Chang, Tien-Hao, Cervantes-Pérez, Sergio Alan, Zheng, Chunfang, Sankoff, David, Tang, Haibao, Purbojati, Rikky W., Putra, Alexander, Drautz-Moses, Daniela I., Schuster, Stephan C., Herrera-Estrella, Luis, and Albert, Victor A.

Published
2017

215. TEM crack tip investigations of SCC

Author

Lozano-Perez, Sergio and M. L. Jenkins

Subjects
620, Transmission electron microscopy, Aluminum alloys, Cracking, Stress corrosion, Research
Abstract

Over the last few years, TEM has become a powerful technique to study cracks and specially crack tips. However, the number of publications including TEM results has not grown as it was expected. The main reason for this might be difficulties in the sample preparation. In this work we present a novel FIB sample preparation technique which has proved to be an ideal tool for preparing cross sectional samples containing crack tips. The morphology of intergranular stress corrosion cracking (IGSCC) has been investigated in Alloy 600 subjected to constant load and slow strain rate tests in simulated primary circuit pressurized water reactor conditions. Cracks were observed to nucleate at high-angle grain boundaries and propagate to depths of a few tens of micrometer along such boundaries, still in the initiation stage. Electron diffraction, energy dispersive x-ray (EDX) and electron energy loss spectroscopy (EELS) have been used to identify the different corrosion products and precipitates. Elemental mapping was employed to reveal changes in composition in the crack tip area. Major observations at cracks and grain boundaries include: the presence of different oxides in different locations, differences in grain boundary oxides and open crack/free surface oxides. These observations suggest that IGSCC involves oxygen diffusion through a porous oxide region along grain boundaries to the bare metal. This is a novel concept that offers an alternative to previous mechanisms proposed in the literature e.g. H embrittlement, slip-dissolution, etc., for which no supporting evidence has been found.

Published
2002

216. Pitt County Elections to kick off at ECU

Author

Capula-Perez, Sergio

Subjects
City councils, Elections, Voting, News, opinion and commentary, Sports and fitness
Abstract

Byline: Sergio Capula-Perez East Carolina University kicked off early voting in the city of Greenville on Monday at its local voting location at ECU's Main Campus Student Center in room [...]

Published
2023

217. Student organizations' thoughts on Josh Stein and his visit to Greenville

Author

Capula-Perez, Sergio

Subjects
News, opinion and commentary, Sports and fitness
Abstract

Byline: Sergio Capula-Perez North Carolina's State Attorney General, Josh Stein, visited Greenville, North Carolina, last Friday on the last day of his 'NC Strong' tour which began on Oct. 10 [...]

Published
2023

221. Acceptance and Suitability of a Novel Virtual System in Chronic Acquired Brain Injury Patients

Author

Albiol-Pérez, Sergio, Pruna-Panchi, Edwin-Patricio, Escobar-Anchaguano, Ivón-Patricia, Bucheli-Andrade, José-Gioberty, Pilatasig-Panchi, Marco-Antonio, Mena-Mena, Luis-Enrique, Segovia-Chávez, Janeth, Bernis, Aracne, Zumbana, Paulina, Kacprzyk, Janusz, Series editor, Rocha, Álvaro, editor, Correia, Ana Maria, editor, Adeli, Hojjat, editor, Reis, Luis Paulo, editor, and Mendonça Teixeira, Marcelo, editor

Published
2016
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222. A Neurocognitive Virtual Rehabilitation System for Children with Cerebral Palsy: A Preliminary Usability Study

Author

Albiol-Pérez, Sergio, Pruna-Panchi, Edwin-Patricio, Escobar-Anchaguano, Ivón-Patricia, Pilatasig-Panchi, Marco-Antonio, Mena-Mena, Luis-Enrique, Segovia-Chávez, Janeth, Bernis, Aracne, Zumbana, Paulina, Kacprzyk, Janusz, Series editor, Rocha, Álvaro, editor, Correia, Ana Maria, editor, Adeli, Hojjat, editor, Reis, Luis Paulo, editor, and Mendonça Teixeira, Marcelo, editor

Published
2016
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239. Energy and exergy analysis of possible alternatives to R134a in a vapour compression refrigeration cycle of a water cooler unit

Author

Bencharif, Mehdi, Croquer Perez, Sergio, Poncet, Sébastien, Bencharif, Mehdi, Croquer Perez, Sergio, and Poncet, Sébastien

Abstract

In this paper, the energy and exergy performance of a vapour-compression refrigeration cycle of a water dispenser unit has been analyzed theoretically using different refrigerants as possible alternative substitutes to R134a. The selected low ?Global Warming Potential (GWP) ? refrigerants are: HydroFluoroOlefins (HFO) R1234yf and R1234ze(E), HydroCarbons (HC) R290 and R600a, and HydroFluoroCarbon (HFC) R152a. The process was evaluated based on the evaporator and condenser temperatures, which range between -10 and 5?C and between 30 and 45?C, respectively. The theoretical model based on the first and second laws of thermodynamics has been developed using the Matlab environment. The performances of the vapor compression cycle are discussed in terms of coefficient of performance, exergy destruction and exergy efficiency. The results show that the maximum COP achieved is 5.12 and 5.10 for R152a and R600a respectively, the highest total exergy destruction is about 82.82 W for R290, the highest exergy efficiency is about 55.12% for R600a., Communication présentée lors du congrès international tenu conjointement par Canadian Society for Mechanical Engineering (CSME) et Computational Fluid Dynamics Society of Canada (CFD Canada), à l’Université de Sherbrooke (Québec), du 28 au 31 mai 2023.

Published
2023

240. ASSESSMENT OF CELLULOSE NANOFIBERS FROM BOLAINA BLANCA WOOD OBTAINED AT THREE SHAFT HEIGHTS.

Author

Andre Arango-Perez, Sergio, Enrique Gonzales-Mora, Héctor, Patricia Ponce-Alvarez, Silvia, Aurelio Gutarra-Espinoza, Abel, and Joao Cárdenas-Oscanoa, Aldo

Subjects
*FOURIER transform infrared spectroscopy, *MECHANICAL alloying, *ELECTRON microscope techniques, *METHYLENE blue, *ULTRAVIOLET-visible spectroscopy
Abstract

Cellulose nanofibers (CNF) could be obtained from diverse lignocellulosic sources, among them wood. Regarding this, it is important to clarify if the shaft section of the tree could influence the CNF characteristics. This study evaluated cellulose nanofibers from Guazuma crinita (bolaina blanca) obtained at different heights of the longitudinal axis of the shaft of trees from a three-and-a-half-year-old plantation. The wood was subjected to pulping, bleaching and subsequent mechanical milling using a Changsha Samy XYQM-2L planetary ball mill to obtain cellulose nanofibers. The product was characterised using analytical techniques: scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy. Additionally, the degree of polymerisation was determined. The effect of longitudinal position on cellulose nanofibers characteristics was evaluated by comparing means using ANOVA and Kruskal-Wallis statistical tests. The yield of cellulose nanofibers production from the high, middle and basal sections was 32,1 %, 33,6 % and 31 %, respectively. The obtained cellulose nanofibers exhibited a significantly larger diameter for the high zone (84 nm) compared with the middle (75 nm) and basal (69 nm) zones; the length remained above the micrometre range. With respect to degree of polymerisation, a decrease was evidenced with respect to the increase in shaft height; the basal zone exhibited a degree of polymerisation of 300, a significantly higher value than the middle and high zones, which exhibited degree of polymerisation of 249 and 211, respectively. The product showed typical cellulose type I polymorphism and crystallinity indexes of 76 %, 93 % and 96 % for the high, middle and basal sections, respectively. Regarding the thermostability of cellulose nanofibers, the maximum degradation rate of cellulose nanofibers occurred between 335 °C and 341 °C, with cellulose nanofibers from the basal area being the most stable. The adsorption of the methylene blue dye on cellulose nanofibers was evaluated; an efficiency > 60 % was found. [ABSTRACT FROM AUTHOR]

Published
2024
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241. Training characteristics and performance of two male elite short‐distance triathletes: From junior to "world‐class".

Author

Cejuela, Roberto and Selles‐Perez, Sergio

Subjects
*ENDURANCE sports training, *MATHEMATICAL models, *PHYSICAL training & conditioning, *EXERCISE physiology, *CYCLING, *THEORY, *DESCRIPTIVE statistics, *EXERCISE intensity, *ATHLETIC ability, *SWIMMING, *SPORTS events, *SPRINTING
Abstract

Objective: The sports‐science literature lacks data on training and performance characteristics of international elite athletes over multiple seasons. The present case study provided general training characteristics and performance data of two male short‐distance triathletes in the Junior, U23, and international Elite categories. Methods: General training and performance data of two male elite triathletes were described in swimming, cycling, and running segments from the 2015 to 2022 season. The training load was presented using the ECO model while the training intensity distribution (TID) was a triphasic model. Results: Both triathletes increased their performance throughout the seasons. Triathlete A increased his VO2max in cycling by 20.6%, in running by 16.7%. His power at VO2max and his speed at VO2max by 18.9% and 11.0%, respectively. Triathlete B improved his VO2max by 17.8% in cycling, by 16.1% in running and his power at VO2max by 24%, and his speed at VO2max by 14.3%. The triathletes trained on average 14–17 h a week. The TID model was polarized. Conclusions: To achieve the top international level, it is necessary to consider the following measures: training load progression; improvements in physiological variables; and participation in international events starting from youth categories. [ABSTRACT FROM AUTHOR]

Published
2023
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249. 2. ESTUDIO A LARGO PLAZO DE LA ESTABILIDAD DE LA SEÑAL AURICULAR, FIBRILACIÓN AURICULAR Y COMPLICACIONES DE LOS SISTEMAS DE MARCAPASOS VDD FRENTE A LOS DDD

Author

Cavero, Alberto Carrión, del Mar Robles Musso, María, Musso, Emilio Robles, Ocete, Francisco Javier Quesada, Ocete, Blanca Quesada, Mulet, Sonia Cardona, Pérez, Sergio Luengo, Lizarraga, Julián Abdala, Bello, Javier Jiménez, Valverde, Isabel Montes, Marín, Amelia Alonso, Tavira, Adrián Valverde, Chaume, Ana Payá, Serrano, Rafael Payá, and Dorador, Aurelio Quesada

Published
2023
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