Time-dependent simplifi ed spherical harmonics formulations for a nuclear reactor system

A. Carreno,A. Vidal-Ferrandiz,D. Ginestar,G. Verdú 한국원자력학회 2021 Nuclear Engineering and Technology Vol.53 No.12

The steady-state simplified spherical harmonics equations (SPN equations) are a higher order approximation to the neutron transport equations than the neutron diffusion equation that also have reasonablecomputational demands. This work extends these results for the analysis of transients by comparing oftwo formulations of time-dependent SPN equations considering different treatments for the time derivatives of the field moments. The first is the full system of equations and the second is a diffusiveapproximation of these equations that neglects the time derivatives of the odd moments. The spatialdiscretization of these methodologies is made by using a high order finite element method. For the timediscretization, a semi-implicit Euler method is used. Numerical results show that the diffusive formulation for the time-dependent simplified spherical harmonics equations does not present a relevant lossof accuracy while being more computationally efficient than the full system.

Managing Complications in Abdominoplasty: A Literature Review

Vidal, Pedro,Berner, Juan Enrique,Will, Patrick A. Korean Society of Plastic and Reconstructive Surge 2017 Archives of Plastic Surgery Vol.44 No.5

Background Abdominoplasty, with or without liposuction, is among the most frequently performed aesthetic procedures. Its main objective is to improve the body contour by means of excising redundant skin and fat tissue. Although abdominoplasty is considered a safe procedure with high satisfaction rates, intraoperative and postoperative complications can become a challenge for the surgical team. The aim of this article is to offer a synopsis of the most common complications arising after abdominoplasty, along with evidence-based guidelines about how to prevent and treat them. Methods A systematic MEDLINE search strategy was designed using appropriate Medical Subject Headings (MeSH) terms, and references were scanned for further relevant articles. Results According to the published case series, local complications are considerably more common than complications with systemic repercussions. Approximately 10% to 20% of patients suffer a local complication following abdominoplasty, while fewer than 1% suffer a systemic complication. Prevention and management strategies are critically discussed for complications including seroma, haematoma, infection, skin necrosis, suture extrusions, hypertrophic scars, neurological symptoms, umbilical anomalies, deep venous thrombosis and pulmonary thromboembolism, respiratory distress, and death. Conclusions The complications of abdominoplasty vary in severity and in the impact they have on the aesthetic outcomes. Recommendations for prevention and management are based on various levels of evidence, with a risk of observer bias. However, most complications can be treated appropriately following the current standards, with satisfactory results.

Preparation of Hybrid Devices Containing Nylon/M(II)Pc-TTF (M=Cu, Zn) Films with Potential Optical and Electrical Applications

María Elena Sánchez-Vergara,Diana Monserrat López-Romero,Pablo Vidal-García,Christian Jiménez-Jarquín,Aline Hernandez-García,Omar Jiménez-Sandoval 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.3

Hybrid devices consisting of metallophthalocyanines, MPcs(M=Zn, Cu), doped with a Tetrathiafulvalene (TTF) derivativeand dispersed in nylon 11 have been prepared by using a thermalevaporation technique. The effects of thermal relaxation on thestructure and morphology of the samples were studied by FT-IRspectroscopy, SEM and X-ray diffraction. The thermalrelaxation in nylon 11 produced a crystalline arrangement in theα- and β-form MPc molecules. Changes in conductivity of thedevices suggest the formation of alternative paths for carrierconduction. It was found that the temperature-dependent electriccurrent in Zn devices showed a semiconductor behavior. Finally,the optical direct and indirect band gap of these hybrid deviceswas evaluated from optical absorption measurements. The bandgap values were found to decrease from 3.7 to 1.38 eV (for theZnPc device), and from 1.9 to 1.1 eV (for the CuPc device), withthe addition of TTF in the polymeric matrix.

A Series of Novel Esters of Capsaicin Analogues Catalyzed by Candida antarctica Lipases

Tania Diaz-Vidal,Luis Carlos Rosales-Rivera,Juan C. Mateos-Díaz,Jorge A. Rodríguez 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.1

Capsaicin analogues are typically synthetized by condensation of the amide group of vanillylamine with a fatty acid derivative. The enzyme of choice to perform this reaction is Candida antarctica lipase B; however, this enzyme is unable to react with the phenolic substituents of the vanillyl ring. So far, this can only be achieved chemically, resulting in capsaicin esters with higher lipophilicity and less irritation than the parent compound. In need of searching for new capsaicin derivatives, we investigated the transesterification of the phenolic OH group of capsaicin and several capsaicin analogues by Candida antarctica lipase A (CALA) with vinyl esters. Capsaicin esters were successfully synthetized with a reaction yield of 80.6% and 57.5% with vinyl butyrate and vinyl laurate, respectively. When the reactions were performed with capsaicin analogues of different acyl chain lengths, CALA exhibited a noticeable transesterification preference for medium-length capsaicin analogues. In an attempt to explore the catalytic limits of CALA, we performed the transesterification of capsaicin from Capsicum oleoresin. The results showed similar transesterification yields to those obtained with semi-pure capsaicin. Within our knowledge, this is the first report to achieve the synthesis of phenolic OH esters of capsaicin and capsaicin analogues by enzymatic means.

Managing Complications in Abdominoplasty: A Literature Review

Pedro Vidal,Juan Enrique Berner,Patrick A. Will 대한성형외과학회 2017 Archives of Plastic Surgery Vol.44 No.5

Background Abdominoplasty, with or without liposuction, is among the most frequently performed aesthetic procedures. Its main objective is to improve the body contour by means of excising redundant skin and fat tissue. Although abdominoplasty is considered a safe procedure with high satisfaction rates, intraoperative and postoperative complications can become a challenge for the surgical team. The aim of this article is to offer a synopsis of the most common complications arising after abdominoplasty, along with evidence-based guidelines about how to prevent and treat them. Methods A systematic MEDLINE search strategy was designed using appropriate Medical Subject Headings (MeSH) terms, and references were scanned for further relevant articles. Results According to the published case series, local complications are considerably more common than complications with systemic repercussions. Approximately 10% to 20% of patients suffer a local complication following abdominoplasty, while fewer than 1% suffer a systemic complication. Prevention and management strategies are critically discussed for complications including seroma, haematoma, infection, skin necrosis, suture extrusions, hypertrophic scars, neurological symptoms, umbilical anomalies, deep venous thrombosis and pulmonary thromboembolism, respiratory distress, and death. Conclusions The complications of abdominoplasty vary in severity and in the impact they have on the aesthetic outcomes. Recommendations for prevention and management are based on various levels of evidence, with a risk of observer bias. However, most complications can be treated appropriately following the current standards, with satisfactory results.

Adaptive time-step control for modal methods to integrate the neutron diffusion equation

Carreno, A.,Vidal-Ferrandiz, A.,Ginestar, D.,Verdu, G. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.2

The solution of the time-dependent neutron diffusion equation can be approximated using quasi-static methods that factorise the neutronic flux as the product of a time dependent function times a shape function that depends both on space and time. A generalization of this technique is the updated modal method. This strategy assumes that the neutron flux can be decomposed into a sum of amplitudes multiplied by some shape functions. These functions, known as modes, come from the solution of the eigenvalue problems associated with the static neutron diffusion equation that are being updated along the transient. In previous works, the time step used to update the modes is set to a fixed value and this implies the need of using small time-steps to obtain accurate results and, consequently, a high computational cost. In this work, we propose the use of an adaptive control time-step that reduces automatically the time-step when the algorithm detects large errors and increases this value when it is not necessary to use small steps. Several strategies to compute the modes updating time step are proposed and their performance is tested for different transients in benchmark reactors with rectangular and hexagonal geometry.

High-Contrast Infrared Absorption Spectroscopy via Mass-Produced Coaxial Zero-Mode Resonators with Sub-10 nm Gaps

Yoo, Daehan,Mohr, Daniel A.,Vidal-Codina, Ferran,John-Herpin, Aurelian,Jo, Minsik,Kim, Sunghwan,Matson, Joseph,Caldwell, Joshua D.,Jeon, Heonsu,Nguyen, Ngoc-Cuong,Martin-Moreno, Luis,Peraire, Jaime,Al American Chemical Society 2018 NANO LETTERS Vol.18 No.3

<P>We present a wafer-scale array of resonant coaxial nanoapertures as a practical platform for surface-enhanced infrared absorption spectroscopy (SEIRA). Coaxial nanoapertures with sub-10 nm gaps are fabricated via photolithography, atomic layer deposition of a sacrificial Al<SUB>2</SUB>O<SUB>3</SUB> layer to define the nanogaps, and planarization via glancing-angle ion milling. At the zeroth-order Fabry-Pérot resonance condition, our coaxial apertures act as a “zero-mode resonator (ZMR)”, efficiently funneling as much as 34% of incident infrared (IR) light along 10 nm annular gaps. After removing Al<SUB>2</SUB>O<SUB>3</SUB> in the gaps and inserting silk protein, we can couple the intense optical fields of the annular nanogap into the vibrational modes of protein molecules. From 7 nm gap ZMR devices coated with a 5 nm thick silk protein film, we observe high-contrast IR absorbance signals drastically suppressing 58% of the transmitted light and infer a strong IR absorption enhancement factor of 10<SUP>4</SUP>∼10<SUP>5</SUP>. These single nanometer gap ZMR devices can be mass-produced via batch processing and offer promising routes for broad applications of SEIRA.</P> [FIG OMISSION]</BR>

Development of a Web Database System for a Comprehensive Hypertension Management Program in the Primary Health Care Setting of Urban Areas of Peru

조혜연,Jorge A. Estrada Vidal,Oscar O. Giraldo Castillo,Luis A. Mayta Mamani,남은우 대한의료정보학회 2019 Healthcare Informatics Research Vol.25 No.1

Objectives: The objective of this case report is to introduce the development process, structure, characteristics, and effectiveness of the web database (DB) system developed for the hypertension management program in the primary health care setting in the low-income urban areas of Peru. Methods: A Korean research team cooperated with a Peruvian IT startup company to develop a web DB system to improve the data management of the hypertension management program. The entire web application infrastructure was hosted using the Amazon Web Service. Two different web platforms were established for the user groups of health workers and researchers (program managers). Results: A total of 2,827 program participants were registered in the web DB system until December 2017. Health professionals can input the participant data while providing consultation to the program participants, and the data is accumulated in the web DB in real time. Input errors or data loss is prevented by setting restrictions in the data entry system. During the 4-year project period, 7,696 hours of working time and USD 39,536.48 for data management were saved as the result of web DB system utilization. Conclusions: The developed web DB system contributed to improve the health condition of the health program participants by providing necessary information to the health professionals at the right time. This case report could be a reference for other researcher to develop web databases for their own context, especially in developing countries.

Magnetohydrodynamic Simulation of Tungsten Wire in Wire-Array Z Pinch

Kim, D.-K.,Chittenden, J. P.,Lebedev, S. V.,Marocchino, A.,Suzuki-Vidal, F. WILEY-VCH Verlag 2010 Contributions to plasma physics Vol.50 No.2

<P>The magnetohydrodynamic behavior of tungsten wire ablating in wire-array Z pinch discharge on MAGPIE is simulated in a two-dimensional fine-grid domain using the GORGON code. A nonideal resistivity model has been implemented in the simulation to obtain plasma transport coefficients in the high density regime along with a screened hydrogenic model to calculate the radiative cooling. Starting from the initial state of warm dense plasma, the evolution of ablated wire is demonstrated to show its explosion and implosion dynamics as a function of discharge time and then the computed profile of electron density is compared with the contour lines reproduced from the measurement by a laser interferometer during the early stage of discharge. The comparison overall shows a fair agreement in terms of the magnitude and the profile shape while some discrepancies can be attributed to the simplified description of the internal wire core physics (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

A New Mixture Criterion for the Improvement of the Compressive Strength of Adobe Using Zeolite as Stabilizer

Rosa Angélica Lara-Ojeda,Juana María Miranda-Vidales,Lilia Narváez-Hernández,Juan Manuel Lozano de Poo 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.8

The use of zeolite as a stabilizer for adobe has proven to have the ability to improve its physical and chemical properties. This is shown in the positive results in terms of strength gain and water absorption resistance in adobe blocks. In this work, an investigation was carried out to evaluate the use of zeolite as adobe stabilizer. The adobes were made with two different types of soil with different content of zeolite (5, 10, 15, 20% by weight) maintaining the zeolite-lime ratio 1:1. The samples were tested on compressive strength and water absorption. The deterioration of the adobes was analyzed under conditions of extreme humidity. The results of this study revealed that adobe behavior is influenced by the synergistic relationship between soil, zeolite and lime, showing significant changes in compressive strength even under extreme humidity conditions. It was also observed that the chemical composition of the soil influenced the development of the pozzolanic reaction. The stabilization of adobes with 15% of zeolite showed the best mechanical behavior, before and after deterioration assay. Hence, zeolite promises to be a good alternative as a stabilizer in adobe construction systems.