Repositorio Institucional de CIMAV (Centro de Investigación en Materiales Avanzados)
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Determinación del coeficiente global de transferencia de calor de un intercambiador de calor compacto para su aplicación en calor solar para procesos industriales.
Get PDFEn este trabajo se presentan los resultados experimentales del coeficiente global de transferencia de calor por unidad
de área (UA) de un intercambiador de calor compacto automotriz, manufacturado en la ciudad de Durango. Para poder
calcular el UA se elaboró un programa en el software Engineering Equation Solver (EES), el cual realiza el cálculo
correspondiente mediante el método de la diferencia media logarítmica de temperatura (LMTD) y el método efectividad-
NTU.
Durante el proceso experimental se monitoreó la temperatura del agua y aire a la entrada y salida del intercambiador
de calor; flujos de agua y aire a través del intercambiador de calor.
Se muestra una serie de graficas que permiten observar el comportamiento de las variables involucradas en este estudio.
El presente trabajo contribuye al conocimiento del comportamiento térmico de un intercambiador de calor de
manufactura local en la ciudad de Durango para su posible aplicación en sistemas de calor solar para procesos industriales
EXPLORATION OF ORNAMENTAL PLANT MARKETING CHANNELS. CHIHUAHUA´S VIVERISTS
Get PDFOrnamental plants are a highly valued product in many parts of the world, due to their sensorial
characteristics, support for biodiversity and occupation of labor. Mexico is one of the important producers in
the world, also distinguished by good quality products. The objective of this exploratory study is to present a
framework of opportunities to strengthen the commercialization of ornamentals and structure distribution
channels according to the needs of the local consumer, in which interviews and documentary research propose
different solutions for the association of producers In question, for decision-making and strategy development.
The conclusions propose the actions to be undertaken by the floriculture companies studied in order to increase
their competitivenes
The effect of fullerene soot on the mechanical properties of chitosan
Get PDFChitosan is a polysaccharide obtained by deacetylating chitin, which is the major constituent of the
exoskeleton of crustaceous water animals [1]. When chitosan is reinforced by the addition of carbon
species, its properties improve and therefore its application go beyond the usual, being an interesting
topic in the fields of materials science and bioengineering [2]. By reinforcing chitosan through a suitable
process that allows the reinforcer to be distributed and dispersed within the matrix, it will be an effective
use to improve its mechanical properties
Interpretation of X-ray Absorption Spectra of 0.94(Na0.5Bi0.5)TiO3-0.6BaTiO3 Titanium Using Ab initio Modeling
No full textWe performed X-ray absorption spectroscopy measurements on Ti K-edge of the ceramic 0.94(Na0.5Bi0.5) TiO3-0.6BaTiO3
Al-Si Alloys Automotive, Aeronautical, and Aerospace Applications
No full textThis book details aluminum alloys with special focus on the aluminum silicon (Al‐Si) systems – that are the most abundant alloys second only to steel. The authors include a description of the manufacturing principles, thermodynamics, and other main characteristics of Al‐Si alloys. Principles of processing, testing, and in particular applications in the Automotive, Aeronautical and Aerospace fields are addressed.https://www.springer.com/gb/book/978331958379
La relación Estructura-Simetría-Propiedades en Cristales y Policristales
No full textintegra en una presentación accesible las ideas y métodos de la cristalofísica y el análisis de texturas. La obra explica numerosos porqués relativos al origen de las propiedades físicas de los materiales, desde el nivel de la red cristalina hasta la escala de los objetos macroscópicos de nuestra vida cotidiana. El texto está escrito de manera que los conceptos y las herramientas difíciles de la cristalofísica (tensores, teoría de grupos) son “descubiertos” por el lector a través de ejemplos sencillos y argumentos cualitativos previos a presentaciones formales. La idea de simetría, su presencia, su descripción y su decisiva influencia en las propiedades de todos los materiales de la naturaleza, es el hilo conductor que unifica la presente obra.https://www.researchgate.net/publication/39022040_La_relacion_estructura-simetria-propiedades_en_cristales_y_policristales_LE_Fuentes_Cobas_ME_Fuentes_Monter
Synthesis, characterization and photocatalytic evaluation of potassium hexatitanate (K2Ti6O13) fibers
Get PDFPotassium hexatitanate have been scarcely studied as a photocalalytic material for the
hydrogen production from water splitting. The aim of the present study is to synthetized
and characterized K2Ti6O13 fibers in order to evaluate their photocatalytic activity towards
the efficient production of hydrogen. Materials were characterized by XRD, BET, UV–Vis
and SEM. The viability of obtaining K2Ti6O13 via the flux method using boric acid subjected
to different melting temperatures and cooling media (air or water) was carried out. The
amount of used flux enabled the production of a liquid phase in which the TiO2 and K2O
reacted to form K2Ti6O13 with various morphologies, according to results. The melting
temperature did not significantly influence the microstructure presented by the materials.
Fibers were produced with sizes varying from 12 to 35 μm in length and 260 – 530 nm in
diameter as well as with a specific surface area of 4.1 m2/g and 2.3 m2/g for a heat
treatment at 900 °C (C21) and 1000 °C (C22), respectively. Band gap energies of these
titanates fell within the electromagnetic spectrum from 3.2 eV for both samples. Maximum
hydrogen production was achieved by (C21) with 2,387 μmolH2/gcat, while the lowest
production was observed for sample (C22) with 1,538 μmolH2/gcat at 8 hours of irradiation.
From these results the crystals of potassium hexatitanate exhibited high photocatalytic
activity for water splitting and they can be considered as potential photocatalysts for H2
production
BIOFOULING CONTROL BASED ON IRON NANOPARTICLE COATING FOR RO MEMBRANES
Get PDFThe effect of biofouling control measures, based on iron nanoparticle (FeNP) coating for RO membranes,
was determined using accelerated biofouling experiments on a commercial polyamide. The zeta potential,
XRD, roughness, contact angle, permeance and flux were determined for coated and uncoated membranes.
Feed water was obtained from the Sea of Cortez, Mexico, which was pretreated, sterilized and inoculated
with a high concentration (109 CFU ml -1) of bacteria found naturally in the Sea of Cortez. In order to
evaluate the anti-biofouling effect, the total organic carbon, total cell count and optical density were
determined for the biofilm cake layer. The FeNP coating resulted in a significant reduction (32%) in the
membrane permeance for pure water. Nonetheless, after the biofouling test the coated membranes showed
90% less biofilm cake layer, 67% lower total cell count and a 42% reduction in optical density. This
highlights the biocide effect of the FeNPs, which could have a practical and important application in sea
water desalination. Due to the easy synthesis of FeNPs, they have the potential to extend the useful life of
RO membranes without significantly increasing membrane production costs, thus decreasing the total
water cost
Estimation of nitrous oxide by irrigation in parks with treated wastewater in the city of Chihuahua, Mexico
Get PDFNitrous oxide is very important in the environment because it is a potent greehouse gas with a global warming potential of 170-290 times grater that carbon dioxide. This gas is considered to be responsible for approximately 6% of the total effect of the greehouse and its concentration at the substation is increasing at a rate of 2% per year