Estudio de la transferencia de calor en un octavo del conjunto combustible del reactor nuclear de alto desempeño refrigerado por agua supercrítica / Heat transfer study in one eighth of the high performance supercritical water-cooled reactor fuel assembly

El reactor nuclear de agua ligera de alto desempeño es la versión europea del reactor refrigerado por agua supercrítica, propuesto como uno de los candidatos para la Generación IV de reactores nucleares. En este trabajo se evaluó la capacidad para predecir el comportamiento de la transferencia de calor hacia el agua supercrítica en los subcanales de 1/8 del conjunto combustible del HPLWR, mediante códigos de la Dinámica de Fluidos Computacional utilizando dos modelos de turbulencia: el modelo de esfuerzos de Reynolds, desarrollado por Speziale y el modelo k-ω de transporte de esfuerzos cortantes. Se realizó un estudio de sensibilidad de malla que garantizó la independencia de los resultados numéricos respecto del tamaño y distribución de los elementos de la malla. Se calcularon las distribuciones axiales de temperatura en la envoltura y en los elementos combustibles, además de las distribuciones de temperatura del agua en la zona refrigerante y en la zona moderadora. Se compararon los resultados de los dos modelos de turbulencia y se mostró que no se obtuvo ninguna diferencia apreciable en los valores de la temperatura promedio del agua supercrítica calculada con los modelos de turbulencia utilizados. Sin embargo, los resultados numéricos utilizando el modelo de turbulencia SST mostraron mayores valores de temperatura del combustible y de temperatura superficial de la envoltura de los elementos combustibles que los calculados con el modelo SSG

The high-performance light-water nuclear reactor is the European version of the supercritical water-cooled reactor, proposed as one of the candidates for Generation IV of nuclear reactors. This paper assesses the ability to predict the heat transfer behavior to supercritical water in the sub-channels of the 1/8 HPLWR fuel assembly by codes of Computational Fluid Dynamics using two models of turbulence (the Reynolds stress model developed by Speziale and the k-ω shear stress transport model). A mesh sensitivity study was performed to guarantee the independence of the numerical results regardless the size and distribution of the mesh elements. Temperature distributions were calculated in the fuel rods, in the clad, and in water both in the cooling zone and moderator zone. The results of the two turbulence models were compared. No appreciable difference was obtained in the values of the supercritical water average temperature calculated with the turbulence models used. However, the numerical results using the SST turbulence model show higher values regarding the temperature of both fuel rods and clad surface compared to those calculated with the SSG model

Surgical treatment results of secondary tunnel-like subaortic stenosis after congenital heart disease operations / 中华胸心血管外科杂志

Objective To summarize surgical results of secondary tunnel-like subaortic stenosis( STSS) after congenital heart disease( CHD) operations, analyze the pathogenesis of STSS, evaluate the operative effect and prognosis.Methods We analyzed clinical data of 25 patients who underwent surgical repair for STSS in Fuwai Hospital from January 2009 to December 2015.There were 17 males and 8 females.CHD types included double outlet right ventricle, ventricular septal defect and par-tial atrioventricular septal defect, et al.The median age of the patients when they received their first CHD operations was 1 year (1 month to 42 years).The median age of the patients when they received TSS repair was 5 years and 8 months(2 years and 10 months to 48 years) .The surgical types contained modified Konno procedure , Konno procedure, resection of the conal sep-tum, resection of fibromuscular ridge and myectomy, removal and reconstruction of the intraventricular baffle.Results All the patients successfully received their TSS repair .There was no surgical death in this study .The preoperative gradient of aortic valve pressure was 81(43 to 159)mmHg(1 mmHg=0.133 kPa), and the postoperative gradient was 8.2(4.0 to 46.2) mm-Hg.Ⅲ degree atrioventricular block was occurred in 2 patients after operation and both 2 patients needed to set permanent pacemaker.All the patients were followed up after discharge for a median duration of 2 years( 4 months to 6 years) .During follow-up, none of the patients had any clinical symptom or subaortic restenosis , and there was no late death .Conclusion The pathogenesis of STSS is perhaps related to turbulent flow and shear stress to the left ventricular outflow tract , resulting in the proliferation of fibromuscular marterials and stenosis in the left ventricular outflow tract .The modified Konno procedure and resection of the conal septum are safe and effective.

New techniques of on-line biological sample processing and their application in the field of biopharmaceutical analysis

Biological sample pretreatment is an important step in biological sample analysis. Due to the diversity of biological matrices, the analysis of target substances in these samples presents significant challenges to sample processing. To meet these emerging demands on biopharmaceutical analysis, this paper summarizes several new techniques of on-line biological sample processing: solid phase extraction, solid phase micro-extraction, column switching, limited intake filler, molecularly imprinted solid phase extraction, tubular column, and micro-dialysis. We describe new developments, principles, and characteristics of these techniques, and the application of liquid chromatography-mass spectrometry (LC-MS) in biopharmaceutical analysis with these new techniques in on-line biological sample processing.

Problems in Cardiac Output Measurement and Clinical Understanding / 대한마취과학회지

Cardiac output measurement is so important that it is widely used in anesthesia and intensive care practice.However, the basic principles for the measurement of each device are not taught for clinicians.This review article describes considerable points for each device; 1) temperature sensors and integration problem for pulmonary artery catheter, 2) angle of ultrasonic probe and meaning of turbulent flow for transesophageal echocardiography, 3) angle of ultrasonic probe and meaning of pulsatile laminar flow for CarioQ, 4) end-tidal and arterial carbon dioxide concentration for Noninvasive cardiac output, 5) the concept of convolution for the arterial pulse wave and arterial resistance for Vigileo, and 6) effect size as a statistical viewpoint of comparison in device effectiveness.As a clinician we should not interpret the value of cardiac output as an absolute meaning, but do as a relative trend considering these theoretical errors.

Estimation of the Possible Age for Using Various Types of Inhaler by In-Check Inspiratory Flow Meter(TM)

PURPOSE: It is important to select and use kinds of Inhaler appropriate to the age of the patient and severity of symptoms. Several kinds of Inhaler have been developed and recommended according to each inhaler's resistance and usage method. We evaluated the usable age of 4 inhalers (turbulent flow inhalers, multi unit dose inhalers, breath actuated MDI, and autohalers) by measuring peak inspiratory flow(PIF) using In-Check(TM) Inspiratory Flow Meter. METHODS: Ninety three patients aged from 3 to 7 years(mean 57+/-12.9 mo.) who had admitted to CHA hospital from July 2000 to April 2001 were enrolled. Study patients were divided into 4 groups according to age:3-4 years of age(group A, n=31), 4-5 years of age(group B, n=32), 5-6 years of age(group C, n=18), and 6-7 years of age(group D, n=12). RESULTS: Out of total 93 patients, 23(71%), 27(84%), 17(94%) patients of each group A, B, C and all 12 patients of group D could use the 4 types of inhaler through adequated education. In all four groups, height, body weight and age were significantly correlated(P<0.05). Usable age, height and weight of children who can use turbulent flow inhaler(TFI) were each 8 year 7 month old, 144 cm, 32.0 kg, and those of multi unit dose inhaler(MUD) were 2 year 10 month old, 92 cm, 12.0 kg. Also that of breath-actuated MDI were 1 yr 8 months, 83 cm, 8.5 kg and that of autohaler were 2 yr 8 months, 91 cm, 11.0 kg. CONCLUSION: We concluded that the ability to use inhalers correlated with height, weight and age of the patients. Multi unit dose inhalers, Breath actuated MDI and Autohaler are useful after 3 years of age through adequate education.

Experimental Study on the Characteristics of Turbulent Flow in a Model Abdominal Aortic Aneurysm / 대한의료정보학회지

An experimental investigation was carried out to study the characteristics of turbulent flow in a model abdominal aortic aneurysm. Hot-wire techniques were used to measure the two components of mean velocity and the three components of the Reynolds stresses along a horizontal plane in streamwise locations extending from 2 diameters upstream to 1 diameter downstream of a model abdominal aortic aneurysm. Results show that a small vortex is established in an abdominal aortic aneurysm bulge and a severe variation of the Reynolds stresses was identified.