La Charreri>a

Torre, Fernando Torres de la,Torres de la Torre, Fernando 한국외국어대학 서반아어과 1986 AULA Vol.4 No.1

Micro-computed tomographic evaluation of the flow and filling ability of endodontic materials using different test models

Torres Fernanda Ferrari Esteves,Guerreiro-Tanomaru Juliane Maria,Chavez-Andrade Gisselle Moraima,Pinto Jader Camilo,Berbert Fábio Luiz Camargo Villela,Tanomaru-Filho Mario 대한치과보존학회 2020 Restorative Dentistry & Endodontics Vol.45 No.2

Objectives: This study compared the flow and filling of several retrograde filling materials using new different test models. Materials and Methods: Glass plates were manufactured with a central cavity and 4 grooves in the horizontal and vertical directions. Grooves with the dimensions used in the previous study (1 × 1 × 2 mm; length, width, and height respectively) were compared with grooves measuring 1 × 1 × 1 and 1 × 2 × 1 mm. Biodentine, intermediate restorative material (IRM), and mineral trioxide aggregate (MTA) were evaluated. Each material was placed in the central cavity, and then another glass plate and a metal weight were placed over the cement. The glass plate/material set was scanned using micro-computed tomography. Flow was calculated by linear measurements in the grooves. Central filling was calculated in the central cavity (mm3 ) and lateral filling was measured up to 2 mm from the central cavity. Results: Biodentine presented the least flow and better filling than IRM when evaluated in the 1 × 1 × 2 model. In a comparison of the test models, MTA had the most flow in the 1 × 1 × 2 model. All materials had lower lateral filling when the 1 × 1 × 2 model was used. Conclusions: Flow and filling were affected by the size of the test models. Higher grooves and materials with greater flow resulted in lower filling capacity. The test model measuring 1 × 1 × 2 mm showed a better ability to differentiate among the materials.

Harnessing Technology in the Evolving Tourism Servicescape during the Post-Covid-19 Era

Torres, Arnelyn Manaluz 차세대컨버전스정보서비스학회 2022 차세대컨버전스정보서비스기술논문지 Vol.11 No.4

The tourism industry is reopening after two years of disruption due to the COVID-19 pandemic. With its re-emergence, new ways of welcoming, receiving, and serving tourists and visitors will be necessary to restore their travel confidence. Governments and destinations should address tourists' health concerns and reassure them to feel at ease, secure, and safe while traveling. This paper argues that technology is an essential strategic partner for redesigning the tourism servicescape. A tourism servicescape combines products, places, services, and activities that contribute to tourists' overall experience. It also includes the interactions between tourists and several organizations at different touchpoints. This study attempts to redesign the tourism servicescape in the Post-Covid-19 by leveraging technology and aligning it with service delivery and interaction. Five technology pillars would facilitate a new service landscape in the travel and tourism industry. For each of these pillars, the author explores how to harness technology and how it can benefit organizations, businesses, and tourists. Technology will likely play an essential role in realigning tourism services and business models in the post-COVID-19 era.

Mass transfer analysis for CO₂ bubble absorption in methanol/Al₂O₃ nanoabsorbents

Torres Pineda, Israel,Kim, Dongmin,Kang, Yong Tae Elsevier 2017 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.114 No.-

<P><B>Abstract</B></P> <P>In this paper computational fluid dynamics (CFD) analysis is carried out to investigate CO<SUB>2</SUB> bubble absorption characteristics in methanol/Al₂O<SUB>3</SUB> nanoabsorbents. Bubble size, rising velocity and mass transfer rate are compared to the previous experimental results for validation. It is found that the distance traveled for each CO<SUB>2</SUB> bubble increases as the concentration of Al<SUB>2</SUB>O<SUB>3</SUB> increases, which, in consequence, increases the residence time between liquid and gas phases resulting in higher interfacial mass transfer rates. For the case of a bubble rising in the gap between walls, the wall shear stress has a major effect on the bubble diameter and rising velocity which in consequence affects the mass transfer coefficient. It is concluded that the mass transfer coefficient enhances by about 40% by adding Al₂O<SUB>3</SUB> nanoparticles (0.01vol%) compared with pure methanol absorbent from the experimental and simulation results. It is also concluded that the use of nanoparticles has a higher impact on mass transfer rate than it does on mass transfer amount, which depends on the residence time and travel distance of CO<SUB>2</SUB> bubbles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mass transfer analysis is carried out for CO<SUB>2</SUB> bubble absorption in nanoabsorbents. </LI> <LI> CO<SUB>2</SUB> absorption enhancement by nanoabsorbents is evaluated. </LI> <LI> Mass transfer coefficient enhances by about 40% by adding Al₂O<SUB>3</SUB> nanoparticles (0.01vol%). </LI> <LI> The use of nanoparticles has a higher impact on mass transfer rate than it does on mass transfer amount. </LI> </UL> </P>

Micro-computed tomographic evaluation of the flow and filling ability of endodontic materials using different test models

Torres, Fernanda Ferrari Esteves,Guerreiro-Tanomaru, Juliane Maria,Chavez-Andrade, Gisselle Moraima,Pinto, Jader Camilo,Berbert, Fabio Luiz Camargo Villela,Tanomaru-Filho, Mario The Korean Academy of Conservative Dentistry 2020 Restorative Dentistry & Endodontics Vol.45 No.1

Objectives: This study compared the flow and filling of several retrograde filling materials using new different test models. Materials and Methods: Glass plates were manufactured with a central cavity and 4 grooves in the horizontal and vertical directions. Grooves with the dimensions used in the previous study (1 × 1 × 2 mm; length, width, and height respectively) were compared with grooves measuring 1 × 1 × 1 and 1 × 2 × 1 mm. Biodentine, intermediate restorative material (IRM), and mineral trioxide aggregate (MTA) were evaluated. Each material was placed in the central cavity, and then another glass plate and a metal weight were placed over the cement. The glass plate/material set was scanned using micro-computed tomography. Flow was calculated by linear measurements in the grooves. Central filling was calculated in the central cavity (㎣) and lateral filling was measured up to 2 mm from the central cavity. Results: Biodentine presented the least flow and better filling than IRM when evaluated in the 1 × 1 × 2 model. In a comparison of the test models, MTA had the most flow in the 1 × 1 × 2 model. All materials had lower lateral filling when the 1 × 1 × 2 model was used. Conclusions: Flow and filling were affected by the size of the test models. Higher grooves and materials with greater flow resulted in lower filling capacity. The test model measuring 1 × 1 × 2 mm showed a better ability to differentiate among the materials.

Analyzing corrosion rates of TiO₂ nanotubes/titanium separation passive layer under surface and crystallization changes

Torres, I. Zamudio,Dominguez, A. Sosa,Bueno, J.J. Perez,Meas, Y.,Lopez, M.L. Mendoza,Dector, A. Techno-Press 2021 Advances in nano research Vol.10 No.3

The evaluation of the corrosion resistance of titanium with a TiO2 nanotubes top layer was carried out (TiO2 NT). These nanostructures were evolved into anatase nanoparticles without heat treatment in an aqueous medium, which is a novel phenomenon. This work analyzes the layer between the nanotube bottom and the substrate, which is thin and still susceptible to corrosion. The bottom of TiO2 nanotubes having Fluor resulting from the synthesis process changed between amorphous to crystalline anatase with a crystallite size of about 4 nm, which influenced the corrosion rates. Four kinds of samples were evaluated. A) NT by Ti anodizing; B) NTSB for Ti plates, either modifying its surface or anodizing the modified surface; C) NT-480 for anodized Ti and heat-treated (480℃) for reaching the anatase phase; D) NTSB-480 for Ti plates, first, modifying its surface using sandblast, after that, anodizing the modified surface, and finally, heat-treated to 480℃ to compare with samples having induced crystallization and passivation. Four electrochemical techniques were used to evaluate the corrosion rates. The surfaces having TiO2 nanotubes with a sandblast pre-treatment had the highest resistance to corrosion.

Wild mushroom consumption in the P’urhépecha Plateau at Michoacán, México: social, ethnomycological and nutritional issues

Torres-Gómez Mariano,Gómez-Peralta Marlene,Vázquez-Marrufo Gerardo 한국식품연구원 2023 Journal of Ethnic Foods Vol.10 No.4

Among Mesoamerican cultures, P’urhépecha settlers inhabiting Michoacán State in Central Mexico preserve ancestral tradition on mushrooms eating. Most mycological knowledge available for this ethnical group has been addressed in the Pátzcuaro’s Lake zone, whereas P’urhépecha communities in other cultural and ecological relevant geographic areas remain unstudied. Thus, this work describes the ethnomycological knowledge of a scarcely analyzed Arantepacua P’urhépecha community at Michoacán Plateau region. Through structured interviews and field collections, data on the use, knowledge, biomass extraction and nomenclature of wild mushrooms were obtained. A list of P’urhépecha names to design 16 wild mushrooms species and 11 fruitbody components is documented and studied community used Spanish popular names to describe 21 wild mushrooms species and 11 fruitbody structures. Most valuable consumed mushroom species for Arantepacua settlers belong to the Amanita, Boletus, Hypomyces and Ramaria genera. Gender roles on mushrooms collect and cooking, new terms in P’urhépecha dialect to refer the parts of a fruitbody and vegetative mycelium, as well as local recipes and nutritional relevance of the mushroom species consumed by studied community are addressed and discussed. The ethnomycological knowledge documented contributes new terms in P’urhépecha to name the parts of an agarical fruitbody, the mycelium and empirical knowledge about mycorrhizal associations. This was the first P’urhépecha ethnomycological study made outside the Lake Pátzcuaro basin.

Characterization of mandibular molar root and canal morphology using cone beam computed tomography and its variability in Belgian and Chilean population samples

Torres, Andres,Jacobs, Reinhilde,Lambrechts, Paul,Brizuela, Claudia,Cabrera, Carolina,Concha, Guillermo,Pedemonte, Maria Eugenia Korean Academy of Oral and Maxillofacial Radiology 2015 Imaging Science in Dentistry Vol.45 No.2

Purpose: This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. Materials and Methods: We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. Results: The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. Conclusion: In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning.

How image-processing parameters can influence the assessment of dental materials using micro-CT

Torres Fernanda Ferrari Esteves,Reinhilde Jacobs,Mostafa EzEldeen,Karla de Faria-Vasconcelos,Guerreiro-Tanomaru Juliane Maria,Bernardo Camargo dos Santos,Mário Tanomaru-Filho 대한영상치의학회 2020 Imaging Science in Dentistry Vol.50 No.2

Purpose: The aim of this study was to evaluate the influence of voxel size and different post-processing algorithms on the analysis of dental materials using micro-computed tomography (micro-CT). Materials and Methods: Root-end cavities were prepared in extracted maxillary premolars, filled with mineral trioxide aggregate (MTA), Biodentine, and Intermediate Restorative Material (IRM), and scanned using micro- CT. The volume and porosity of materials were evaluated and compared using voxel sizes of 5, 10, and 20 μm, as well as different software tools (post-processing algorithms). The CTAn or MeVisLab/Materialise 3-matic software package was used to perform volume and morphological analyses, and the CTAn or MeVisLab/Amira software was used to evaluate porosity. Data were analyzed using 1-way ANOVA and the Tukey test (P<0.05). Results: Using MeVisLab/Materialise 3-matic, a consistent tendency was observed for volume to increase at larger voxel sizes. CTAn showed higher volumes for MTA and IRM at 20 μm. Using CTAn, porosity values decreased as voxel size increased, with statistically significant differences for all materials. MeVisLab/Amira showed a difference for MTA and IRM at 5 μm, and for Biodentine at 20 μm. Significant differences in volume and porosity were observed in all software packages for Biodentine across all voxel sizes. Conclusion: Some differences in volume and porosity were found according to voxel size, image-processing software, and the radiopacity of the material. Consistent protocols are needed for research evaluating dental materials.

LMI-Based Robust Controllers for DC-DC Cascade Boost Converters

Torres-Pinzon, Carlos Andres,Giral, Roberto,Leyva, Ramon The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

This paper presents two different robust controllers for boost converters with two stages in a cascade. The first robust controller is monovariable; that is, the duty-cycle is the same for the two switches. The monovariable controller ensures that some prescribed constraints on pole placement and control effort are met, and optimizes the load disturbance rejection, while takes into account the uncertainty in certain parameters. The first controller is then compared with a multivariable robust controller; that is, with independent duty cycles in each switch. The multivariable controller takes into account the same uncertainty, constraints and optimization function. The comparison shows that the multivariable controller performs better at the expense of a slightly more complex implementation; that is, the multivariable controller provides a better rejection of the load disturbance. The paper also describes simulations and experimental results that are in perfect agreement with theoretical derivations.