Two-step numerical procedure on the removal process of gaseous potassium chloride generated from waste incineration via the injection of sulfate-based additives.

Gaseous potassium chloride (KCl) that constitutes a relatively large portion of the combustion gas of municipal solid waste can condense on the surface of boiler heat exchanger tubes, causing severe corrosion attacks. To reduce the chlorine-induced high-temperature corrosion, sulfate-based additives have been used. In this study, a two-step numerical procedure is proposed to quickly predict the effect of the injection of sulfate-based additives on the removal of gaseous KCl. A computational fluid dynamics (CFD) simulation is first carried out to obtain the temperature distribution. Then, the thermal decomposition of sulfate additives, sulfation of gaseous KCl, and condensation of K2SO4 are calculated to predict the species concentration profiles at the temperature conditions given by the CFD simulation. After validation with a laboratory-scale experiment using [Formula: see text] , the procedure is applied to a pilot-scale boiler to examine the effects of [Formula: see text] , [Formula: see text] , and [Formula: see text] . The calculation results show that each additive has an optimal injection temperature range: approximately 800 °C for [Formula: see text] and 1000 °C for both [Formula: see text] and [Formula: see text] , which are consistent with the values reported in the literature. The expressions for the stoichiometric KCl removal efficiency of each additive are derived and compared with the calculated efficiencies.

[Psychometric Properties and Item Evaluation of Korean Version of Night Eating Questionnaire (KNEQ)].

PURPOSE: The aim of this study was to develop a Korean version of Night Eating Questionnaire (KNEQ) and test its psychometric properties and evaluate items according to item response theory. METHODS: The 14-item NEQ as a measure of severity of the night eating syndrome was translated into Korean, and then this KNEQ was evaluated. A total of 1171 participants aged 20 to 50 completed the KNEQ on the Internet. To test reliability and validity, Cronbach's alpha, correlation, simple regression, and factor analysis were used. Each item was analyzed according to Rasch-Andrich rating scale model and item difficulty, discrimination, infit/outfit, and point measure correlation were evaluated. RESULTS: Construct validity was evident. Cronbach's alpha was .78. The items of evening hyperphagia and nocturnal ingestion showed high ability in discriminating people with night eating syndrome, while items of morning anorexia and mood/sleep provided relatively little information. The results of item analysis showed that item2 and item7 needed to be revised to improve the reliability of KNEQ. CONCLUSION: KNEQ is an appropriate instrument to measure severity of night eating syndrome with good validity and reliability. However, further studies are needed to find cut-off scores to screen persons with night eating syndrome.

Psychometric Properties of the Korean Versions of Three Sleep Evaluation Questionnaires.

Psychometric properties of the Korean versions of three sleep evaluation questionnaires were described to provide tools for practitioners and researchers interested in transcultural studies in Korea. The Pittsburgh Sleep Quality Index (PSQI), the General Sleep Disturbance Scale (GSDS), and the Leeds Sleep Evaluation Questionnaire (LSEQ) were analyzed using data from 959 community-dwelling adults in Korea. Furthermore, cut-off points and prevalence of sleep disturbance were identified. Reliability and concurrent validity for all measures were acceptable. Optimal cut-off points of PSQI, GSDS, and LSEQ with highest Youden's index were 5, 33, and 66, and prevalence of sleep disturbance was 22.1%, 26.3%, and 25.8%, respectively. The Korean PSQI, GSDS, and LSEQ are all valid and reliable tools for detecting sleep disturbance. We provide suggestions for selecting the right tools according to the purpose, setting, and participants of transcultural studies.

Long-term operation of biomass-to-liquid systems coupled to gasification and Fischer-Tropsch processes for biofuel production.

Long-term operation of the biomass-to-liquid (BTL) process was conducted with a focus on the production of bio-syngas that satisfies the purity standards for the Fischer-Tropsch (FT) process. The integrated BTL system consisted of a bubbling fluidized bed (BFB) gasifier (20 kW(th)), gas cleaning unit, syngas compression unit, acid gas removing unit, and an FT reactor. Since the raw syngas from the gasifier contains different types of contaminants, such as particulates, condensable tars, and acid gases, which can cause various mechanical problems or deactivate the FT catalyst, the syngas was purified by passing through cyclones, a gravitational dust collector, a two-stage wet scrubber (packing-type), and a methanol absorption tower. The integrated system was operated for 500 h over several runs, and stable operating conditions for each component were achieved. The cleaned syngas contained no sulfur compounds (under 1 ppmV) and satisfied the requirements for the FT process.

[Psychometric properties of Korean Minimal Insomnia Screening Scale].

PURPOSE: The purposes of this study were to develop a Minimal Insomnia Screening Scale for Korean adults (KMISS) and to evaluate psychometric properties and discriminant ability of the developed scale. METHODS: Data from a cross-sectional survey of 959 Korean adults were analyzed to develop the summated insomnia scale, which was evaluated in terms of reliability, validity, and discriminant ability by receiver operating characteristics (ROC) curve analysis. RESULTS: Item-total correlations ranged between .71-.79 and Cronbach's α was .87. Adequate validity was also evident. ROC-curve analysis showed area under ROC was .87 (95% CI: .84-.90) and identified the optimal cut-off score as ≤ 20 (sensitivity, .83; specificity, .75; positive/negative predictive values, .40/.95). Using this cut-off score, the prevalence of insomnia in the study sample was 26.3% and most frequent among women and the oldest group. CONCLUSION: Data supports the psychometric properties of KMISS as a possible insomnia screening instrument. KMISS also shows promise as a convenient ultra-short screening measure of insomnia for adults and epidemiological studies in community health care settings.