• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.5
• /
• pp.687-694
• /
• 1999

An experimental study was carried out in two laboratory-scale reactors to investigate the effect of heating rate on the behavior of flame front in a pulverized coal flame. Each. reactors had different heating mechanisms. For reactor A losing large heat through transparent quartz wall. pulverized coal particles were ignited by secondary air of 1050K. Flame front could be visualized through the transparent wall. Reactor B was insulated with castable refractory to minimize the heat loss through the reactor wall and accompanied with secondary air of 573K. Flame front was estimated from the gas temperature and species concentration measured using R-type thermocouple(Pt-Pt/Rh 13%) and gas chromatograph at various coal-air ratios and swirl intensities. The flame front position was closely related with the magnitude of heating rate. The heating rate for lifted flame was of the order of $10^4$ to $10^5K/s$ and for coal Ignition at least over $10^4K/s$. The heating mechanism had little impact on the extinction limits. The weak swirl number of 0.68 forced the flame front to move toward the upstream by the rapid mixing of coal and air. The primary/secondary momentum ratio was an inappropriate variable to distinct the liftoff of flame.

• Korean Journal of Community Nutrition
• /
• v.5 no.4
• /
• pp.697-708
• /
• 2000

The purpose of this study is to analyze the contents of the questionnaires used in dietary surveys and to evaluate each item in relation to the item construction strategy. Articles of which the contents were related to food, nutrition, diet, dietary behavior, and related areas. Published from 1997 to 1999 were searched fir and a total of 121 questionnaires were collected and analyzed. The questions in the questionnaires were classified into related areas and sub-areas. Among the keywords in the title of the articles, the term 'nutritional status'(or 'dietary intake status') was most frequently used. The terms such as dietary status, obesity, health, food habit, and dietary behavior were also frequency used. Major topics of the items in the questionnaires varied according to the life cycle of the subjects of the study. The topics most frequently asked in each lift cycle were as follows : overeating, snack, and food preference for preschool- and school-aged children ; anthropometry, weight control, and snack for middle and highschool students : meal skipping, smoking, and drinking for college students : disease, smoking, drinking, and exercise for adults : and smoking, drinking, disease and perceived health for the elderly. Inappropriate questions with complicated language, typographic and grammatic errors, unnecessary words, and negative questions were found. Therefore, care should be taken to construct each question so as to avoid possible misinterpretation. Also, a standardized questionnaire be developed for survey researchers.

• Journal of the Korean Geosynthetics Society
• /
• v.16 no.2
• /
• pp.89-96
• /
• 2017

In this study, CS-H walls with large stiffness were constructed using geosythetics for use in excavation at a depth of 30 m or more in Korea, and in order to construct the CS-H wall suitable for the site conditions, the formulation was examined according to the change in the mixing ratio of the geosythetics and the slump value (slump flow) and as a result, in the target slump 180 mm and the slump flow 500 mm, the formulation was confirmed to meet the mechanical properties such as the initial bending strength, the long-term behavior, and the elastic modulus as well as the economic efficiency. However, in the slump flow 600 mm, the result indicated that the formulation was inappropriate in the mechanical properties such as the initial bending strength, the long-term behavior, and the elastic modulus.

• International journal of steel structures
• /
• v.18 no.5
• /
• pp.1607-1616
• /
• 2018

Quantitatively modeling and propagating all sources of uncertainty stand at the core of seismic fragility assessment of structures. This paper investigates the effects of various sources of uncertainty on seismic responses and seismic fragility estimates of single-layer reticulated domes. Sensitivity analyses are performed to examine the sensitivity of typical seismic responses to uncertainties in structural modeling parameters, and the results suggest that the variability in structural damping, yielding strength, steel ultimate strain, dead load and snow load has significant effects on the seismic responses, and these five parameters should be taken as random variables in the seismic fragility assessment. Based on this, fragility estimates and fragility curves incorporating different levels of uncertainty are obtained on the basis of the results of incremental dynamic analyses on the corresponding set of 40 sample models generated by Latin Hypercube Sampling method. The comparisons of these fragility curves illustrate that, the inclusion of only ground motion uncertainty is inappropriate and inadequate, and the appropriate way is incorporating the variability in the five identified structural modeling parameters as well into the seismic fragility assessment of single-layer reticulated domes.

• Journal of Korean Public Health Nursing
• /
• v.11 no.2
• /
• pp.121-130
• /
• 1997

The community health nursing process is essential in providing community health nursing service to the community. It helps to identify community health problems. to prioritize problems, to provide service. and to evaluate service results. However. it is very rare to find a study which applies the community health nursing process. This study intended to apply the community health nursing process to a urban community. The focus of the study was a community consisting of 533 families in a region of Seoul. The study process was as follows: 1) The data was collected by conducting interviews with community leaders and by collecting surveys from the people of the community. 2) The data was summarized and analyzed. 3) The community nursing diagnosis was identified. 4) The nursing diagnosis was prioritized. 5) The general and specific objectives for service were identified. 6) A specific nursing plan was set up. 7) A detailed evaluation plan was established. Four community nursing diagnoses were identified from the community. 1) The utilization rate of health center was found to be low due to lack of knowledge about the health center and low accessibility. 2) High trafic accident rate due to narrow roads. 3) High prevalence of chronic disease due to inappropriate health behavior. 4) High noise level and foul smell due to inappropriate waste management. Among the four community nursing diagnoses. 'High prevalence of chronic diseases was identified as a priority community nursing problem. The criteria for prioritizing community nursing problems were as follows: number of people involved, fragility of clients. severity of the problem. availability. of resources. concern of the people. readiness of nurses. relevance to the national policy. This study describes the general and specific objectives to solve the high prevalence of chronic health problems. nursing plans. and an evaluation plan.

• Sleep Medicine and Psychophysiology
• /
• v.8 no.2
• /
• pp.138-143
• /
• 2001

Sleepiness is associated with many different conditions and, as a neglected topic, it can be the cause of serious psychological and social disadvantages. In the aspect of learning, additional problems may arise from poor progress in school caused by the effect of sleepiness on concentration, memory, and other cognitive functions. Narcolepsy is by no means the most common cause of excessive sleepiness. Nonetheless, it is not a rarity, especially in young people. The non-specific nature of early features of narcolepsy, combined with very limited awareness that the condition can start in various ways, leads to many misinterpretations. Misinterpretation of narcolepsy symptoms is not confined to the medical profession. Teachers may well be critical of a student with narcolepsy because of their perception of narcolepsy symptoms as laziness, poor motivation, or difficult behavior and dull learning ability. Inappropriate reactions by parents, teachers, and peers, based on misinterpretation of narcolepsy symptoms or the patient's reactions to them, make a difficult situation worse. Especially in Korea, where schooling is focused on college entrance examinations, the problem is very serious and intensified by inappropriate or delayed diagnosis and treatment. Therefore, psychiatrists should be aware that narcolepsy in young adolescents is not rare and that they need to be familiar with its clinical features in both its classic and less obvious forms. Narcolepsy should be suspected if a adolescent's excessive sleepiness can not be explained in other ways. Therefore, we report on two patients who portray the tendency of dull learning ability and are mistaken as idle students. We diagnosed narcolepsy through polysomnography and multiple sleep latency testing. We treated the students with methylphenidate and pemolin. The students showed improvement in learning ability and were able to adapt better to school.

• Phonetics and Speech Sciences
• /
• v.1 no.2
• /
• pp.31-36
• /
• 2009

This study attempted to examine the effects of a portable voice feedback device on the hyperfunctional voice behaviors of children with vocal nodules when they wore the device in their daily lives. The device could set fundamental frequency and intensity at optimal levels for the subjects, It produces an audible alarm for inappropriate hyperfunctional voices beyond the preset levels, In addition, the frequency of hyperfunctional voice behaviors was recorded by the device, therefore the users were able to chart their number of hyperfunctional voice behaviors per day, According to results acquired after having subjects wear the device for 12 weeks, the subjects' frequency of hyperfunctional voice behaviors decreased significantly (p < .01). Especially from the first to fourth week, the frequency of their hyperfunctional voice behaviors declined significantly.

• Journal of the Korean Society of Safety
• /
• v.14 no.2
• /
• pp.19-25
• /
• 1999

The research has extracted two kinds of specimen, one is rolling direction material(R-material) and the other rectangular of rolling direction(V-material), from Al alloy 7075 rolled. We have come to a conclusion by measuring crack propagation behavior with movement type microscope and Replica. 1) R-material shows 130% higher, approx. 39.2MPa in fatigue strength than V-material, approx. 29.4MPa. 2) In crack proportion, contrary to V-material growing directly toward specimen axis, R-material grows neared to shear direction. 3) The life proves that R-material is approx. 122% higher than V-material at 43.1MPa and approx. 135% higher at 47MPa. 4) The correlation between fatigue crack length and fracture life ratio applied to 'log(2a)=A+B ($N/N_f$)'equation shows inappropriate, because property value of Al alloy is low and the difference of chemical composition is high comparing with steel material.

• Journal of the Korean Society of Safety
• /
• v.20 no.2 s.70
• /
• pp.79-83
• /
• 2005

Recently, column-supported wall structural system is frequently adopted in mixed-use high-rise buildings. Due to the sudden change of stiffness at the transfer floor proper load transfer and avoiding stress concentration are very important in column-supported wall structural system. It is revealed by many investigators that 2-dimensional analysis is not reliable and inappropriate selection of element for modeling may lead to erroneous result for gravitational loading. In this study, structural behavior of column-supported wall structure at transfer floor subject to lateral loading is compared by changing modeling methods.

• Korean Journal of Biological Psychiatry
• /
• v.23 no.2
• /
• pp.41-47
• /
• 2016

Dementia with Lewy bodies (DLB) is the second most common causes of dementia. It can exhibit a variety of clinical symptoms including cognitive decline, cognitive fluctuation, visual hallucinations, parkinsonism, REM sleep behavior disorder, hypersensitivity to neuroleptics and autonomic dysfunctions. Despite more well-known criteria for DLB, there are often misdiagnosis and inappropriate treatment. It gives a lot of clinical burden to the clinician as well as to patients and families. When reducing the misdiagnosis, the burden of all will be reduced. The special concern and solicitation are needed in order not to miss the diagnosis when the cardinal features of DLB may not be volunteered by patients and the caregivers. To control the symptoms, clinicians must find and reduce drugs that can have the negative effects on DLB symptoms. There is limited evidence about specific interventions but available data suggest cholinesterase inhibitors improve the cognitive and behavioral symptoms and menmantine slightly improves the global impression.