GAS AND SOLID MIXING IN A THREE PARTITIONED FLUIDIZED BED

There are many gas-solid reaction systems which take place simultaneously in a single reactor, such as coal gasification. By splitting the reactions, high concentrated gases can be obtained without separation processes. Dual fluidized bed was proposed for this purpose. Similarly, simultaneous adsorption/desorption systems with dry sorbent for CO2 capture and the gasification reaction system with a char combustor and a gasifier separately were developed. For improving gas and solid mixing efficiencies of the dual fluidized beds, a hitherto unknown partitioned fluidized bed (PFB) is proposed. A basic concept of PFB is that lower parts between two separated fluidized beds are linked (opened), whereas upper parts are blocked by walls. Solid mixing occurs in lower parts with preventing gas mixing. The solid residence time becomes longer than that of dual fluidized bed and the high conversion of solid can be obtained. In this study, the gas and the solid mixing behaviors were investigated in three partitioned fluidized beds (left, center and right). The size of each fluidized bed is 7 cm (w) X 7 cm (d) X 30 cm (h) and partitioned above the 7 cm of distributor. Air and CO2-air mixture were used as fluidizing gas in each partitioned fluidized bed. For the gas mixing experiments, glass bead particles with 150 micron and density of 2.5g/cm3 were introduced. Outlet gas concentrations of each fluidized bed were analyzed by IR and then the gas exchanges between the reactors were calculated. For the solid mixing experiments, the polypropylene particles with 1000 micron and the density of 0.883 g/cm3 were continuously fed into the reactor. The gas mixing percentages were 0.4 ~ 16.0% of input gas amounts with varying gas velocities. The solid discharge rates in center and right side can be controlled by operating conditions

A Study of Solids and Gas Mixing in a Partitioned Fluidized Bed

A partitioned fluidized bed gasifier has been developed for improving coal gasification performance. The basic concept is to divide a fluidized bed into two parts, a gasifier and a combustor, by a partition. Char is burnt in the combustor and generated heat is supplied to the gasifier by solid mixing. Therefore, solid mixing should be maximized whereas gas mixing between syngas and the combusted gas should be minimized. In this study, gas and solid mixing behaviors were verified in cold model acrylic beds. For monitoring solid mixing behavior, transient temperature trends in the beds were analyzed. A heat source and a heat sink were installed in each bed. Dozens of thermocouples were used to monitor temperature distribution

Sex Differences in Lower Urinary Tract Symptoms in Older Korean Adults Living in Rural Areas: Prevalence, Quality of Life, and Associated Factors

Purpose Urinary incontinence (UI) is associated with nursing home admission, functional decline, and risk of death among community-dwelling older adults. Little information, however, is available on sex differences in lower urinary tract symptoms (LUTS) in older Korean adults exclusively living in rural areas. This study examined sex-related differences in LUTS, factors associated with UI in older adults living in rural areas, and health-related quality of life (HRQoL) in incontinent older adults. Methods This was a cross-sectional study in which face-to-face interviews were conducted at 15 rural community-health centres. A total of 323 older adults aged ≥65 years from rural areas of Korea participated. LUTS prevalence was evaluated and HRQoL was measured using the King’s Health Questionnaire. The chi-square test and t -test were used to examine sex differences in characteristics, LUTS, and HRQoL. Multivariable logistic regression was used to identify risk factors associated with UI. Results Nocturia was the most prevalent symptom, affecting 87% of men and 86% of women. Women (53%) had significantly more UI of any kind than did men (35%) (P=0.007). Urgency UI was the most frequent type of UI in men, whereas stress UI was the most frequent in women. Regarding HRQoL, men had significantly higher scores in the domains of sleep/energy disturbances (P=0.032) than did women, and women reported greater effects from the severity of incontinence (P=0.001) than did men. Arthritis was the only factor associated with UI in men (odds ratio [OR], 6.88; 95% confidence interval [CI], 1.46–32.36). However, women with diabetes mellitus were less likely to have UI than those without (OR, 0.43; 95% CI, 0.23–0.82). Conclusions LUTS were found to be highly prevalent in community-dwelling older Korean adults in rural areas. Interventions to improve sleep and to reduce UI severity are needed for incontinent men and women, respectively

Production of Hydrogen and Carbon Black by Methane Decomposition Using DC-RF Hybrid Thermal Plasmas

A continuous production of carbon black and hydrogen has been investigated by thermal decomposition of methane using a prototype processing system of DC-RF hybrid thermal plasma, which has great advantage over other thermal sources like combustion or DC plasma torches in synthesizing new nanostructured materials by providing high-temperature environment and longer residence time for reactant gases due to its larger hot core region and lower flow velocity. Appropriate operation conditions and reactor geometries for the effective synthesis process are predicted first from the relevant theoretical bases, such as thermodynamic equilibrium calculations, two-dimensional thermal flow analysis, and chemical kinetic simulation. Based on these derived operation and design parameters, a reaction chamber and a DC-RF hybrid torch are fabricated for the processing system, which is followed by methane decomposition experiments with it. The methane injected into the processing system is converted mostly into hydrogen with a small volume fraction of acetylene, and fine carbon particles of 20-50 nm are identified from their TEM images. Material analyses of BET, DBP and XRD indicate that the synthesized carbon black has excellent properties such as large surface area, high electrical conductivity, and highly graphitized structures with good crystallization

Prevalence of human parechovirus and enterovirus in cerebrospinal fluid samples in children in Jinju, Korea

PurposeHuman parechovirus (HPeV) and enterovirus (EV) are causative agents of a sepsis-like illness in neonates and of infections of the central nervous system in young children. The objectives of this study were to assess the prevalence of HPeV3 and EV infection in young children with a sepsis-like illness or with meningitis in Jinju, Korea.MethodsCerebrospinal fluid (CSF) samples were collected from 267 patients (age range, 1 day to 5 years) and assessed for HPeV and EV by performing reverse transcription polymerase chain reaction assay. Amplification products of the VP3/VP1 region of HPeV and of the VP1 region of EV were sequenced to identify the virus type.ResultsHPeV and EV were detected in 3.4% and 7.5% of the total CSF samples assessed, respectively. The age distribution of EV-positive patients (median age, 1.4 months) had a significantly broader range than that of HPeV-positive patients (median age, 7.8 months). The peak seasons for HPeV and EV infection were spring and summer, respectively. The clinical symptoms for HPeV and EV infection were similar, and fever was the most common symptom. Pleocytosis was detected in 22.2% of HPeV-positive patients and 35.5% of EV-positive patients. The VP3/VP1 gene sequence of the nine Korean strains clustered most closely with the Japanese strain (AB759202).ConclusionThe data indicate that HPeV infection is predominant in young infants (<6 months) and that meningitis without pleocytosis was caused by both HPeV and EV infection in children

Botulinum Toxin Injection in the Treatment of Postextubation Dysphagia: A Case Report

Prolonged intubation is known to bring on postextubation dysphagia (PED) in some patients. We have noted that there were some studies to investigate specific type and pattern of PED, which showed large variety of different swallowing abnormalities as mechanisms of PED that are multifactorial. There are several options of treatment in accordance with the management of these abnormalities. A botulinum toxin (BoT) injection into the upper esophageal sphincter (UES) can improve swallowing functions for patients with this disorder, by working to help the muscle relax. In this case, the conventional treatment was not effective in patients with PED, whereas the BoT injection made a great improvement for these patients. This study suggests that the UES pathology could be the main cause of PED