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Vence J, Paz C, Suárez E, Cabarcos A, Conde-Fontenla M. Experimental evaluation of the effect of ozone treatment on the oxidation and removal of dry soot deposits of the exhaust gas recirculation system. Heliyon 2023; 9:e17861. [PMID: 37519737 PMCID: PMC10372213 DOI: 10.1016/j.heliyon.2023.e17861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 08/01/2023] Open
Abstract
The integration of alternative energy sources as a replacement for fossil fuels across various industrial sectors, including power generation, emergency systems, or marine applications, is uncertain. As a result, the utilization of traditional fuels is not anticipated to be fully phased out in the near future. To address this, new technologies, such as those that employ oxidising atmospheres, have been explored as a means to enhance the pollution control capabilities of existing technologies, as the Exhaust Gas Recirculation (EGR) system. In this regard, the present study has assessed the efficacy of ozone atmosphere exposure in mitigating the formation of undesired fouling deposits within the system, with the aim of facilitating more efficient operation of EGR devices and extending their service life. To this end, dry soot samples have been exposed to various ozone atmospheres at different temperatures and ozone concentrations through the utilization of an experimental test bench. The oxidation potential of these atmospheres has been evaluated through the analysis of the deposit mass loss. Likewise, confocal microscopy techniques have been employed to obtain the 3D topography of the fouling samples before and after the ozone treatment, allowing the assessment of the deposit thickness reduction, as well as the surface roughness variation. Additionally, thermogravimetric analysis has been conducted to examine the effects of the oxidation processes on fouling samples composition. The findings of this study have revealed that ozone atmospheres have been effective in reducing deposit mass at ozone treatment temperatures above 100 °C. The reduction in mass has reached 78.5% and 91.8% with treatment temperature of 140 °C with ozone concentrations of 30 gO3/m³ and 50 gO3/m³, respectively. It has also been established that treatment conditions with ozone concentrations of 30 gO3/m³ and 50 gO3/m³ are effective in reducing the thickness of deposits even at intermediate treatment temperatures, resulting in a thickness reduction of 78.6% and 81.1% at 80 °C, respectively. Additionally, it has been observed that the ozone exposure leads to the increase in the proportion of volatile material within the deposit.
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Affiliation(s)
- Jesús Vence
- CINTECX, Universidade de Vigo, Campus Universitario Lagoas-Marcosende, 36310, Vigo, Spain
| | - Concepción Paz
- CINTECX, Universidade de Vigo, Campus Universitario Lagoas-Marcosende, 36310, Vigo, Spain
| | - Eduardo Suárez
- CINTECX, Universidade de Vigo, Campus Universitario Lagoas-Marcosende, 36310, Vigo, Spain
| | - Adrián Cabarcos
- CINTECX, Universidade de Vigo, Campus Universitario Lagoas-Marcosende, 36310, Vigo, Spain
| | - Marcos Conde-Fontenla
- CINTECX, Universidade de Vigo, Campus Universitario Lagoas-Marcosende, 36310, Vigo, Spain
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Vence J, Gil C, González-Rodríguez L, López-Álvarez M. Thermal Behavior of Graphene Oxide Deposited on 3D-Printed Polylactic Acid for Photothermal Therapy: An Experimental-Numerical Analysis. J Funct Biomater 2023; 14:jfb14020080. [PMID: 36826879 PMCID: PMC9959892 DOI: 10.3390/jfb14020080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/20/2023] [Accepted: 01/28/2023] [Indexed: 02/01/2023] Open
Abstract
The present work evaluates the thermal behavior of graphene oxide (GO) when deposited on 3D-printed polylactic acid (PLA), in order to develop a medical device for photothermal therapy applications. An experimental-numerical analysis was performed to assess the photothermal conversion capacity, based on the power emitted by a NIR (785 nm) laser, and the subsequent temperature distribution on the GO-PLA material. The influence of the deposited mass of GO and the PLA thickness was studied through 40 different scenarios. The results estimated a value of photothermal conversion efficiency of up to 32.6%, achieved for the lower laser power density that was tested (0.335 mW/mm²), and a high mass value of deposited GO (1.024 × 10-3 mg/mm²). In fact, an optimal mass of GO in the range of 1.024-2.048 × 10-3 mg/mm2 is proposed, in terms of absorption capacity, since a higher mass of GO would not increase the conversion efficiency. Moreover, the study allowed for an estimation of the thermal conductivity of this specific biomaterial (0.064 W/m·K), and proved that a proper combination of GO mass, PLA thickness, and laser power can induce ablative (>60 °C, in a concentrated area), moderate (50 °C), and mild (43 °C) hyperthermia on the bottom face of the biomaterial.
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Paz C, Cabarcos A, Vence J, Gil C. Development of an active contour based algorithm to perform the segmentation of soot agglomerates in uneven illumination TEM imaging. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Paz C, Suárez E, Vence J, Cabarcos A. Analysis of the volume of fluid (VOF) method for the simulation of the mucus clearance process with CFD. Comput Methods Biomech Biomed Engin 2019; 22:547-566. [PMID: 30773045 DOI: 10.1080/10255842.2019.1569637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The clearance of mucus through coughing is a complex, multiphase process, which is affected principally by mucus viscosity and airflow velocity; however, it is also critically affected by the thickness of the two layers of mucus-the serous and gel layers-and oscillation level. The present study examines the effects of the latter parameters more closely. To do so, the mucus clearance process is simulated with a transient 3D volume of fluid (VOF) multiphase model in ANSYS Fluent. The model includes mucus' bilayer properties and a wide range of boundary conditions were tested. The model was analysed in both a straight tube and a realistic trachea. Ultimately, the model was able to both capture air-mucus interface wave evolution and predict the overall behaviour of the clearance process. The results were consistent with experimental clearance data and numerical airflow simulations, which indicates our methodology is appropriate for future studies. Ultimately, the mere presence of the serous layer was found to increase mucus clearance by more than 15 percent. An oscillating flow enhanced clearance by up to 5 percent. Interestingly, interface wave steepness was found to be inversely correlated with mucus thickness, but directly with mucus velocity, which suggests it will be an interesting parameter for further study.
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Affiliation(s)
- Concepción Paz
- a School of Industrial Engineering , University of Vigo , Vigo , Spain.,b Biofluids Research Group, Galicia Sur Heath Research Institute (IIS Galicia Sur) , SERGAS-UVIGO , Vigo , Spain
| | - Eduardo Suárez
- a School of Industrial Engineering , University of Vigo , Vigo , Spain.,b Biofluids Research Group, Galicia Sur Heath Research Institute (IIS Galicia Sur) , SERGAS-UVIGO , Vigo , Spain
| | - Jesús Vence
- a School of Industrial Engineering , University of Vigo , Vigo , Spain
| | - Adrián Cabarcos
- a School of Industrial Engineering , University of Vigo , Vigo , Spain
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Paz C, Suárez E, Parga O, Vence J. Glottis effects on the cough clearance process simulated with a CFD dynamic mesh and Eulerian wall film model. Comput Methods Biomech Biomed Engin 2017; 20:1326-1338. [PMID: 28782386 DOI: 10.1080/10255842.2017.1360872] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In this study, we have reproduced the cough clearance process with an Eulerian wall film model. The simulated domain is based on realistic geometry from the literature, which has been improved by adding the glottis and epiglottis. The vocal fold movement has been included due to the dynamic mesh method, considering different abduction and adduction angles and velocities. The proposed methodology captures the deformation of the flexible tissue, considers non-Newtonian properties for the mucus, and enables us to reproduce a single cough or a cough epoch. The cough efficiency (CE) has been used to quantify the overall performance of the cough, considering many different boundary conditions, for the analysis of the glottis effect. It was observed that a viscous shear force is the main mechanism in the cough clearance process, while the glottis closure time and the epiglottis position do not have a significant effect on the CE. The cough assistance devices improve the CE, and the enhancement rate grows logarithmically with the operating pressure. The cough can achieve an effective mucus clearance process, even with a fixed glottis. Nevertheless, the glottis closure substantially improves the CE results.
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Affiliation(s)
- Concepción Paz
- a School of Industrial Engineering , University of Vigo , Vigo , Spain.,b Biofluids Research Group , Galicia Sur Heath Research Institute (IIS Galicia Sur), SERGAS-UVIGO , Vigo , Spain
| | - Eduardo Suárez
- a School of Industrial Engineering , University of Vigo , Vigo , Spain.,b Biofluids Research Group , Galicia Sur Heath Research Institute (IIS Galicia Sur), SERGAS-UVIGO , Vigo , Spain
| | - Oscar Parga
- a School of Industrial Engineering , University of Vigo , Vigo , Spain
| | - Jesús Vence
- a School of Industrial Engineering , University of Vigo , Vigo , Spain
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Paz C, Suárez E, Vence J. CFD transient simulation of the cough clearance process using an Eulerian wall film model. Comput Methods Biomech Biomed Engin 2016; 20:142-152. [DOI: 10.1080/10255842.2016.1206532] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
Based on a study of the composition of urban solid waste (USW) and of socioeconomic variables in Morelia, Mexico, generation rates were estimated. In addition, the generation of residential solid waste (RSW) and nonresidential solid waste (NRSW) was forecasted by means of a multiple linear regression (MLR) analysis. For residential sources, the independent variables analyzed were monthly wages, persons per dwelling, age, and educational level of the heads of the household. For nonresidential sources, variables analyzed were number of employees, area of facilities, number of working days, and working hours per day. The forecasted values for residential waste were similar to those observed. This approach may be applied to areas in which available data are scarce, and in which there is an urgent need for the planning of adequate management of USW.
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Affiliation(s)
- O Buenrostro
- Instituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico.
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