Carmen Salazar Hernández - Academia.edu (original) (raw)

Papers by Carmen Salazar Hernández

Revista de Aplicaciones de la Ingeniería

Tetraethoxysilane is the most commonly used precursor for obtaining mesoporous silica, it is econ... more Tetraethoxysilane is the most commonly used precursor for obtaining mesoporous silica, it is economically expensive, so the use of inexpensive precursors such as sodium silicate or silicic acid are of interest for the economic production of said materials; silicic acid is generally obtained from sodium silicate by adjusting the pH of the system to 3-4 or through the use of ion exchange resins, this second methodology allows to eliminate the use of acid or basic catalysts in the synthesis of materials, which potentiates these materials for bioparticle encapsulation applications. The effect of the poly-condensation of silicic acid in obtaining mesoporous silica has been little evaluated, so this work shows the study of the effect of the degree of polycondensation of silicic acid on the textural properties of the materials, observing that at 0 and After 48 h of Si(OH)4 aging, the synthesized materials show a bimodal distribution of their pores at 4 and 8 nm, observing the majority pres...

Revista de Ingeniería Mecánica

Nowadays, engineering has attempted to find a way to replace the loss of human limbs with unnatur... more Nowadays, engineering has attempted to find a way to replace the loss of human limbs with unnatural devices that approximate their actual function. Current devices vary from hooks, mechanical prostheses, or simply cosmetic prostheses, where an important component when deciding which one to use is the cost of it, even above functionality. The aim of this article is the development of a mechanical prototype for partial hand prosthesis for patients who have suffered partial (middle and distal phalanges) or total (proximal, middle, and distal phalanges) finger mutilation. The results of this work show that the mechanism and the proposed design of the prosthesis are satisfactory to simulate the movement of a human finger, while the finite element analysis shows that the proposed design can adequately support the loads for extreme conditions.

RSC Advances

The inexpensive lipase Lipex® 100L produced biodiesel from waste cooking oil in a two-step proces... more The inexpensive lipase Lipex® 100L produced biodiesel from waste cooking oil in a two-step process, with an overall yield of 96.3%.

Jorge A. Cervantes Jauregui, Dolores E. Alvarez Gasca, Ramon Zarraga Nunez, Veridiana Reyes Zamud... more Jorge A. Cervantes Jauregui, Dolores E. Alvarez Gasca, Ramon Zarraga Nunez, Veridiana Reyes Zamudio y Carmen Salazar Hernandez Resumen La conservacion arquitectonica de monumentos historicos demanda del trabajo multidisciplinario en el que participen expertos de diversas areas cientificas y tecnologicas. Teniendo en cuenta que es un compromiso la preservacion de la memoria historica para las generaciones futuras, se presenta un panorama de como otras disciplinas contribuyen a este campo. En este trabajo, se hace referencia a los materiales comunes de construccion de monumentos de la ciudad de Guanajuato. Tomando en consideracion esta informacion, generada de estudios geologicos y mineralogicos, se describen los mecanismos generales que deterioran las piedras monumentales. La accion del agua, los microorganismos y los agentes ambientales son los responsables del deterioro y se requieren algunas soluciones para conservar los materiales originales. La consolidacion y el tratamiento hid...

Journal of Nanomaterials, 2018

This work reports the effect of reduction temperature during the synthesis of PdAg catalysts thro... more This work reports the effect of reduction temperature during the synthesis of PdAg catalysts through the polyol process and their evaluation in the ethanol electrooxidation reaction (EOR). The characterization was performed using Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD). The electrochemical evaluation for the ethanol electrooxidation reaction was implemented in alkaline medium using chronoamperometry (CA) and cyclic voltammetry (CV). An important effect of the reduction temperature on electroactivity and catalytic stability was observed: both the maximum current density and the catalytic stability were higher in the catalyst synthesized at the highest temperature (135°C). This performance was associated with the extent of the interaction between Pd and Ag which was measured in terms of the structural expansion of Pd.

Revista de energía química y física, Dec 30, 2023

Revista Mexicana de Ingeniería Química, 2018

Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo int... more Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

ECORFAN Journal Taiwan, Jun 30, 2019

El siguiente trabajo, muestra la factibilidad del uso de materiales meso-porosos de silice en el ... more El siguiente trabajo, muestra la factibilidad del uso de materiales meso-porosos de silice en el pre-tratamiento de efluentes acuosos provenientes de los procesos de cianuracion de minerales; mostrandose una alternativa para la eliminacion de iones indeseables, como el Cu(I) en dicho proceso. Se muestra la cinetica de remocion en lote y columna de complejos de [Cu(CN)X ] -X+1 a pH 10-11 en sistemas sinteticos con concentraciones de 50-250 mgL-1 de Cu, observandose en dichos sistemas una remocion de hasta 90 % del cobre presente en los sistemas sinteticos estudiados en lote y columna respectivamente; mientras que en sistemas provenientes de la cianuracion de una mena de Pena de Bernal Chihuahua, con concentraciones de 150 mgL-1 de Cu, se observo una remocion del 40% del Cu presente, mejorandose la calidad del efluente para su posible recirculacion en dichos sistemas

La modificacion de silice mesoporosa de bajo costo, obtenida a partir de silicato de sodio y su m... more La modificacion de silice mesoporosa de bajo costo, obtenida a partir de silicato de sodio y su modificacion con magnetita, fue obtenida para su uso como adsorbente de plata y su posible recuperacion magnetica. La silica obtenida presento un area superficial externa de 491 cm2 g-1 y diametro de poro promedio de 3.9 nm. Los estudios de adsorcion de plata en un intervalo de 100-500 ppm de Ag, mostraron una capacidad de adsorcion de 86.2 mgg-1 asi como una adsorcion favorable

Resumen— Three different Organic Modified Ceramics (ORMOSILs) base of TEOS/PDMS were studied as a... more Resumen— Three different Organic Modified Ceramics (ORMOSILs) base of TEOS/PDMS were studied as anticorrosive coatings. The ORMOSILs were synthesized using DBTL as polycondensation catalysts; it is an organometallic tin compound which has been little used in the sol- gel process. PDMS content in the coatings were varied from 15% to 40 % by weight; infrared spectroscopy indicated the chemical bonding between the polymer and the silica fragments formed by the TEOS. Moreover, optical microscopy showed that the ceramic coatings were deposited homogeneously on the metal substrate (aluminum). Galvanic corrosion tests indicate excessive wear on the metal surface; while ceramic coating avoided the corrosion.

Revista de Innovación Sistemática

Nowadays the contamination in waters by oily substances turns out to be a problem of world-wide s... more Nowadays the contamination in waters by oily substances turns out to be a problem of world-wide scope and although some methods of removal of oils in water exist; these present some limitations; therefore, this project proposes the use of hydrophobic silicas as absorbent materials for oily substances. Modified silicas (R-SiO2) were synthesized using the Stöber method, modifying the surface by co-condensation. Tetraethyl-orthosilicate (TEOS) and two surface modifiers were used as silica former: Methyl-trimethoxysilane (MeTEOS) and n-octyl-triethoxysilane (nOctyl-TEOS). The R-SiO2 were characterized by infrared spectroscopy identifying the modifying groups and their hydrophobicity was qualitatively evaluated according to the change in solubility in water. Finally, the removability of an automotive motor oil was evaluated by determining the amount of oil removed per gram of modified silica.

International Journal of Refrigeration

Abstract This paper presents a model for a variable-speed liquid chiller integrating a compressor... more Abstract This paper presents a model for a variable-speed liquid chiller integrating a compressor model based on Buckingham π-theorem to accurately predict the system performance when R134a is replaced with R1234yf, using a wide range of data obtained from an experimental setup. Relevant variables such as temperature, pressure, mass and volumetric flow rates, compressor power consumption and rotation speed were measured at several positions along the refrigeration and secondary circuits and were used to validate the developed model. Model results show that cooling capacity and power consumption predicted values are in good agreement with experimental data, within ±5%, being slightly higher for the deviation obtained for R134a than for R1234yf. Moreover, model results indicate that R1234yf has a reduction of coefficient of performance (COP) compared with R134a (between 2 and 11.3%), and that R1234yf COP reduction is diminished at intermediate volumetric flow rate and higher inlet temperature for the evaporator secondary fluid, respectively. On the other hand, an environmental analysis based on TEWI (total equivalent warming impact) method showed that direct emissions are almost negligible for R1234yf. However, there are no environmental benefits in terms of indirect greenhouse gas emissions using R1234yf without system modifications (as for instance the addition of internal heat exchanger or R1234yf new design components), which are required to reduce the liquid chiller climate change contribution using it as low GWP alternative in comparison with the typically used R134a refrigerant.

Journal of Cultural …, 2010

Hybrid stone consolidants prepared from tetraethoxysilane (TEOS) and α, ω-hydroxyl-terminated pol... more Hybrid stone consolidants prepared from tetraethoxysilane (TEOS) and α, ω-hydroxyl-terminated polydimethylsiloxane (PDMS-OH) have been considered as one of the most promising approaches to improve the effectiveness of traditional alkoxysilane-based ...

This paper presents the synthesis and characterization of a mesoporous silica obtained from rice ... more This paper presents the synthesis and characterization of a mesoporous silica obtained from rice husk; This silica was used as a new carrier for griseofulvin (antifungal). This silica showed a maximum of 15% by weight of drug adsorption; Studies of adsorption and desorption of N2 suggest silicas drug adsorption mostly goes into the pores of the material. The maximum rate of release of the drug adsorbed on the silica at pH 7 was 60%. Moreover, the study of drug - SiO2 system in controlling the growth of C. albicans observing control of 90 % in the growth of the fungus for a maximum period of 6 h, with minimum dosages of 750 mg of SiO2-drug corresponding to 112.5 mg of drug. Furthermore, a null pharmacological activity both griseofulvin and silica separately administered was observed. The results indicated that the SiO2- rice can be an excellent carrier for griseofulvin. Keyword— SiO2-farmaco, biogenica, control, crecimiento, griseofulvina.

Silica was obtained from rice husk, this type of silica is also known as SiO2-rice, was investiga... more Silica was obtained from rice husk, this type of silica is also known as SiO2-rice, was investigated as drug delivery for the folic acid. The SiO2-rice was obtained from calcinations at 600 °C and its textural properties were compared with mesoporous silica (MS). The maximum folic acid adsorption on SiO2-rice was at the 18 % weight, while MS adsorbs 19 % weight. An important pH effect on the drug released was observed; both silicas released around 35 % of acid folic at pH 7, while at pH 3 only 3 % of the drug was released. Differential Thermal Analyzer analysis suggests that the folic acid was not crystallized into the porous of the silica; therefore, it is possible that the drug was trapped within the complex network of pores preventing their full release. However, the drug released for 400 μg of folic acid, a commercial dose, indicated that until 93 % of drug could be released for the silicas at pH of 5.5; a minor desorption was observed by commercial tablet.

What is the importance of the concept of information measure in quantum mechanics? To answer, it ... more What is the importance of the concept of information measure in quantum mechanics? To answer, it is necessary to try to establish the importance of the concept of information, which is a general concept and perfectly applicable to any case. For example: What do they have in common codes used to send messages from a communications satellite and the bases of a DNA molecule? How does the second law of Thermodynamics and Communication, to the extent that is possible to speak of the entropy of a musical score? Why the intricate problems of probability is related to the way we express ourselves orally or in writing? The answer to all is information and the fact that one concept can link different ideas so reveals its great generality and power. Until the forties, had not been defined information as a scientific term, and this definition was quite new, different from all the common meanings, and precisely because they were described with sufficient accuracy for mathematicians and engineers...

El oro ocluido en matrices de silices, por lo general se encuentra en tamanos del orden de los na... more El oro ocluido en matrices de silices, por lo general se encuentra en tamanos del orden de los nanometros y es practicamente imposible de extraer bajo metodologias costeables. En estos casos el tratamiento de dichos minerales consiste en una fina molienda, que permita disociar o romper finamente los granos del mineral, permitiendo que el oro sea accesible a los diversos extractantes que se deseen utilizar para el beneficio de este (comunmente, NaCN); el uso de moliendas exhaustivas (pulverizacion) en estos procesos eleva considerablemente el costo de la produccion, por lo que las menas que contienen el llamado oro encapsulado no son procesadas; es por ello que la busqueda de metodologias que permitan eficientemente disociar o destruir dicha matriz silicea es de interes en el procesamiento de minerales. Aqui se propone el uso de un pre-tratamiento quimico para el beneficio de este tipo de minerales. Dicho pre-tratamiento consiste en la disolucion parcial de la matriz silicea con poli...

Resumen en: In this paper a joint theoretical and experimental study examines the ability of diet... more Resumen en: In this paper a joint theoretical and experimental study examines the ability of diethyleneglycol as a ligand to form silicon complexes. Due to the kno...

Journal of Scientific and Technical Applications

In this paper, composite materials reinforced with natural fibers were studied, such as: Jute (MC... more In this paper, composite materials reinforced with natural fibers were studied, such as: Jute (MC-RY) and Manta (MC-RM) as a proposal for new materials for the manufacture of a prototype for automotive defense. The materials were manufactured as laminates and characterized mechanically through stress, bending, impact and Brinell hardness index tests. The results indicated that both reinforcers improved the mechanical strength of the matrix by up to 71%, as well as the impact energy absorption by 14%. The mechanical properties for MC-RY determined in flexure (bending = 56 MPa, Eflection = 4.16 GPa and maximum = 14 mm) were used to perform an impact simulation in two different models created in SolidWork, the results indicated that the MC-RY could be used for the construction of the defense using 3 layers of this material.