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DESING AND SIMULATION OF SCAFFOLDS WITH LATTICE MICROSTRUCTURES FOR BIOPRINTING BONE TISSUE
No full textBACKGROUND: Tissue engineering seeks to improve, maintain, or replace the biological functions of damaged organs or
tissues with biological substitutes such as the development of scaffolds. In the case of bone tissue, they must have excellent
mechanical properties like native bone.
OBJECTIVE: In this work, three geometric models were designed for scaffolds with different structure lattices and porosity
that could be biomechanically suitable and support cell growth for trabecular bone replacement applications in tissue engineering
and regenerative medicine to the proximal femur area.
METHODS: Geometries were designed using computer-aided design (CAD) software and evaluated using finite element
analysis in compression tests. Three loads were considered according to the daily activity: 1177 N for slow walking, 2060 N
for fast walking, and 245.25 N for a person in a bipedal position. All these loads for an adult weight of 75 kg. For each of
them, three biomaterials were assigned: two polymers (poly-glycolic acid (PGA) and poly-lactic acid (PLA)) and one mineral
(hydroxyapatite (HA)). 54 tests were performed: 27 for each of the tests.
RESULTS: The results showed Young’s modulus (E) between 1 and 4 GPa.
CONCLUSION: If the resultant E is in the range of 0.1 to 5 GPa, the biomaterial is considered an appropriate alternative for
the trabecular bone which is the main component of the proximal bone. However, for the models applied in this study, the best
option is the poly-lactic acid which will allow absorbing the acting load
Determinación de Surgencias provocadas por el viento en el océano Pacífico Oriental. Determination of Upwellings caused by the wind in the Eastern Pacific ocean.
No full textSe calcularon las velocidades verticales para
determinar las zonas de surgencias en el océano
Pacífico Oriental del hemisferio Norte colindante
a las costas mexicanas. Con base en la serie de
datos de viento del año 1957 hasta 1975, se
determinaron los componentes meridional y
zonal del flujo total en la capa de deriva para
enero, abril, julio y octubre. También se
calcularon y graficaron los campos de las
isotacas del componente de velocidad vertical
para determinar las zonas de divergencias
positivas y negativas (upwelling y downwelling).
Como resultado se encontró que, en las regiones
del Norte del Pacífico, se presentan las
surgencias más intensas en otoño. En invierno,
en esta región las surgencias se debilitan o se
detienen por completo
El proceso de resiliencia de las estudiantes universitarias que son directivas de una micro o pequeña empresa. Una investigación en el Ciudad Universitaria e Instituto de Ingeniería y Tecnología de la Universidad Autónoma de Ciudad Juárez, Chihuahua, México
No full textLa presente investigación nace a partir del estudio “Los obstáculos de las mujeres universitarias que dirigen una micro o pequeña empresa” (Peña, 2024d), el cual tuvo como objetivo encontrar los obstáculos a los que se enfrentan mujeres estudiantes universitarias al momento de llevar a cabo la gestión de una micro o pequeña empresa. Ante los hallazgos de dicha investigación, se presentó la propuesta de desarrollar este trabajo para conocer la forma en cómo estas mismas mujeres realizan su proceso de resiliencia, que les permite sobreponerse a las dificultades a las que se enfrentan en su doble labor al encontrarse estudiando un grado académico universitario y dirigir o ser dueñas de mypes. Como se ha mencionado en estudios anteriores, el camino de las mujeres en su participación en la esfera pública ha sido de gran relevancia, pero sin duda alguna el trayecto ha sido complejo, por lo que cada mujer ha llevado y desarrollado su proceso de resiliencia con el propósito de sobreponerse ante la
adversidad a la que se enfrenta en su contexto.
En este capítulo, se presentan los resultados del estudio cualitativo que se llevó a cabo
en la Ciudad Universitaria e Instituto de Ingeniería y Tecnología de la Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chihuahua, México. Investigación que forma parte de un estudio cualitativo en 30 universidades de México y Perú, la cual es dirigida por el Comité Académico de la Red Latinoamericana en Estudios de Género (RELEG, 2024). Los principales hallazgos en este contexto fueron los siguientes: La investigación cualitativa realizada a 27 estudiantes universitarias del norte del país reveló que las estudiantes que dirigen una Mype enfrentan diversos obstáculos, sin embargo, la forma en que las estudiantes se sobreponen a estas dificultades es a través de dos categorías principales, las cuales son la administración del tiempo y el trabajo en equipo con los miembros de la micro o pequeña empresa.Para las universitarias es de vital importancia gestionar de manera efectiva su tiempo para cumplir en tiempo y forma con asignaciones académicas y con la dirección de su micro o pequeña empresa, así como tener el respaldo de los miembros de su equipo para hacer frente a situaciones
que se les presentan
Computational analysis and modeling of algal bioreactors performance
No full textModeling of algal bioreactors shows a crescent interest by the potential of algal biomass as a renewable source of energy. Bioreactors may accelerate the algal growth for applications like bioenergy. This process requires uptaking a nutrient through algal inner or surface, which defines the kinetics of algal energy conversion. The ways account for direct and indirect biophotolysis, fermentation either dark or light, and electrochemical either photo- or electrolytic. Considering the first way, algal capacity of fixing a nutrient using sunlight as a photosynthetic organism is attractive, compared with former biofuels that used cane or crops as a source of biomass. In this sense, light transmission is a premise for the success of algal photobioreactors, open and closed. However, control is needed to optimize light transmission and algal motion in water, which naturally allows algal growth through its dispersion. Therefore, understanding photobioreactor hydrodynamics is crucial to make algal growth an efficient process, such as developing new techniques to improve both biomass productivity and energy harvesting. For instance, a centrally illuminated vortex reactor may compete with a parallel plate, which is the most studied photobioreactor. Recent studies showed that a rotating-cylinder promotes Taylor–Couette vortex flow with less energy-consuming in square-section reactors, than using pallets impellors or baffles. Furthermore, this reactor may enhance the exposure of culture to light and increase mass and heat transfer due to controlled flow dynamics. The reactor size and design impacts algal growth and performance
An Integrated Approach to Decision-Making that Maximizes the Plastic Injection Molding Process
No full texthttps://link.springer.com/chapter/10.1007/978-3-031-69382-3_19#chapter-inf
Analysis of job satisfaction in the hotel sector
No full textThe purpose of this research is to evaluate the factors that influence job satisfaction of employees in the hotel sector, in addition to analyzing the differences based on sex, birth generations and hotel category, as well as comparing the levels of intrinsic and extrinsic satisfaction. A correlational quantitative method was used. The study sample consisted of 126 hotel employees. The self-administered survey technique was conducted using instrument S20/23 by Meliá and Peiró (1998). Results indicate a correlation between intrinsic and extrinsic elements of job satisfaction, highlighting that no generational or gender differences were found in perceptions of satisfaction, and regarding the hotel category, only the supervision factor showed differences
Acceleration of Service Life Testing by Using Weibull Distribution on Fiber Optical Connectors
No full textThe service life assessment of previous fatigue stress has a fundamental role in estimating the reliability of products like fiber optical connectors, and should replicate use in severe environments in telecommunications systems. However, the vibration prediction models used in the literature present limitations in vibration life prediction. In this paper, we propose using the insertion loss fatigue life and including it in the Weibull distribution to determine the Weibull parameters η and β to evaluate fiber optic connector reliability R(t) under environmental and mechanical testing stress. We analyzed the failure data of a standard telecommunication fiber optical connector under a program of service life stress testing against that of a fiber optical connector under only mechanical vibration stress testing. The fiber connectors were monitored during the vibration testing to review the
transient change of the optical signal. Their results showed that the reliability of the fiber connectors submitted to the
Energy extraction from a Reissner-Nordström–de Sitter black hole
No full textThe energy extraction from an electrostatic black hole by the decay or splitting of electrically charged particles is analyzed. We determine the energetic conditions that make the extraction process viable and present a general expression for the efficiency in terms of the parameters of the electrostatic black hole and the decaying particles. We also examine the conditions that optimize the efficiency of the extraction process. We analyze two particular cases: the first one is the extraction process from a Reissner-Nordström black hole, for charged test particles with nonvanishing angular momentum; the second one and more interesting corresponds to the energy extraction from a Reissner-Nordström de Sitter black hole. For the latter there are two regions where the energy extraction is possible, the generalized ergosphere and a cosmological ergosphere induced by the cosmological horizon. Under certain conditions the two ergospheres get connected and cover the whole region between the event horizon and the cosmological horizon, and therefore, the energy extraction is possible at any point in the vicinity of the black hole. Moreover, the efficiency of the energy extraction can be the same for different breakup points and also there is the possibility of a different efficiency for the same breakup point. The conditions that maximize the efficiency are determined as well