• Nuclear Engineering and Technology
• /
• v.50 no.6
• /
• pp.890-898
• /
• 2018

Nondestructive inspection (NDI) is an integral part of structural integrity analyses of dry storage casks that house spent nuclear fuel. One significant concern for the structural integrity is stress corrosion cracking in the heat-affected zone of welds in the stainless steel canister that confines the spent fuel. In situ NDI methodology for detection of stress corrosion cracking is investigated, where the inspection uses a delivery robot because of the presence of the harsh environment and geometric constrains inside the cask protecting the canister. Shear horizontal (SH) guided waves that are sensitive to cracks oriented either perpendicular or parallel to the wave vector are used to locate welds and to detect cracks. SH waves are excited and received by electromagnetic acoustic transducers (EMATs) using noncontact ultrasonic transduction and pulse-echo mode. A laboratory-scale canister mock-up is fabricated and inspected using the proposed methodology to evaluate the ability of EMATs to excite and receive SH waves and to locate welds. The EMAT's capability to detect notches from various distances is evaluated on a plate containing 25%-through-thickness surface-breaking notches. Based on the results of the distances at which notch reflections are detectable, NDI coverage for spent nuclear fuel storage canisters is determined.

• Geomechanics and Engineering
• /
• v.35 no.2
• /
• pp.109-119
• /
• 2023

Ground subsidence in urban areas due to excessive development and degraded underground facilities is a serious problem. Geophysical surveys have been conducted to estimate the distribution and scale of cavities and subsidence. In this study, electrical resistivity tomography (ERT) was performed near an area of road subsidence in an urban area. The subsidence arose due to groundwater leakage that carried soil into a neighboring excavation site. The ERT survey line was located between the main subsidence area and an excavation site. Because ERT data are affected by rapid topographic changes and surrounding structures, the influence of the excavation site on the data was analyzed through field-scale numerical modeling. The effect of an excavation should be considered when interpreting ERT data because it can lead to wrong anomalous results. A method for performing 2D inversion after correcting resistivity data for the effect of the excavation site was proposed. This method was initially tested using a field-scale numerical model that included the excavation site and subsurface anomaly, which was a loosened zone, and was then applied to field data. In addition, ERT data were interpreted using an existing in-house 3D algorithm, which considered the effect of excavation sites. The inversion results demonstrated that conductive anomalies in the loosened zone were greater compared to the inversion that did not consider the effects of excavation.

• Research in Plant Disease
• /
• v.15 no.1
• /
• pp.1-7
• /
• 2009

Viruses diagnosed on crops including rice plants from farmers or agricultural extension agencies cover the country were 11 species including Broad bean wilt virus 2 (BBWV2) in 2008. Tomato spotted wilt virus (TSWV) was the most important virus having the detection rate of 22.9%. Two viruses of Tomato yellow leaf curl virus (TYLCV) and Tobacco leaf curl virus (TLCV) inducing leaf yellow and curl diseases on tomatoes were occurred newly with the detection rate of 12.2% and 4.0%, respectively, in 2008. Rice stripe virus (RSV) was occurred on 869.5 ha mainly at Jindo and Haenam areas in Jeollanamdo province. At Jindo area, 12 plots were damaged severely with the infected hill rate of 83.8%. At the main production area of oriental melon at Seongju, almost all fruits from whole sale market at Seongju were infected with Cucumber green mottle mosaic virus (CGMMV) as the detection rate of 87%. The areas occurred TSWV in Korea were 25 totally from 2003 including 7 areas newly reported in 2008 including Naju in Jeoallanamdo. TSWV could be reduced as 0.1 % from 5.3% by covering insect proof net in vinyl house after chemical soil sterilization. Tomato yellow leaf curl disease was occurred on April in 2008 at Tongyoung area in Kyeongsangnamdo, and detected continuously at 13 areas, 7 in Kyeongsangnamdo, 4 in Jeollabukdo and 2 in Jejudo. Potato spindle tuber viroid (PSTVd) was occurred abruptly in a confined space of a civil breeding greenhouse and a cultivar evaluation field followed by disuse 17.4 M/T of potato tubers. No PSTVd was detected at 17 fields cultivated the related potatoes to the bred company by RT-PCR.

• Journal of KIISE:Information Networking
• /
• v.37 no.5
• /
• pp.396-402
• /
• 2010

The tracking of current location of residents is an essential requirement for context-aware service of smart houses. This paper presents a wireless sensor network system which could detect location transition such as entrance and exit to a room and also identify the user who passed the room, without duty of wearing any sort of tag. We designed new sensor node to solve the problem of short operation lifetime of previous work[1] which has two pyroelectric infrared (PIR) sensors and an ultrasonic sensor, as well as a 2.4 GHz radio frequency wireless transceiver. The proposed user identification method is to discriminate a person based on his/her height by using an ultrasonic sensor. The detection idea of entering/exiting behavior is based on order of triggering of two PIR sensors. The topology of the developed wireless sensor network system is simple star structure in which each sensor node is connected to one sink node directly. We evaluated the proposed sensing system with a set of experiments for three subjects in a model house. The experimental result shows that the averaged recognition rate of user identification is 81.3% for three persons. and perfect entering/exiting behavior detection performance.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.15 no.2
• /
• pp.85-90
• /
• 2012

Purpose: Commercial enzyme-linked immunosorbent assay (ELISA) kits have been considered less reliable for children than for adults. The aim of this study was to compare four ELISA kits and in-house immunoblotting based on the analysis of anti-H. pylori-IgG antibody reactivity. Methods: A total of 399 serum samples were collected at the GNU Hospital during 1998-1999. All sera were tested using ELISA and immunoblotting. Statistically significant differences were determined by the $x^2$ test. Results: The overall seropositivity rates using GAP IgG, Genedia IgG, HM-CAP, Pyloriset EIA-G, and immunoblotting were 13.0%, 25.1%, 18.3%, 15.8%, and 62.9%, respectively. Immunoblotting showed a higher seropositivity rate than did all four ELISA kits in all age groups. Genedia IgG had the highest seropositivity among the ELISA kits. The seropositivity rate for children aged 13 to 18 months was lowest, and that of children aged 15 years was highest (90.0%). The seropositivity rate for children aged 7 months to 5 years was significantly lower than that for children aged 6 to 15 years among the four ELISA kits (p<0.0001) and immunoblotting (p=0.02). Conclusion: Immunoblotting is the most sensitive test for detection of anti-Helicobacter pylori IgG antibodies among the serological tests in this study. These results emphasize the need for standardization when commercial ELISA tests are used in different nations or in young age groups. Immunoblotting could be a suitable noninvasive assay for serodiagnosis and seroepidemiologic study of H. pylori infection in Korean children.

• Journal of Veterinary Clinics
• /
• v.30 no.4
• /
• pp.258-263
• /
• 2013

The primary goal of this study was to compute sample sizes required to achieve the each aim of a variety of foot-and-mouth disease (FMD) surveillance programs, using a statistically valid technique that takes the following factors into account: sensitivity (Se) and specificity (Sp) of diagnostic test system, desired minimum detectable prevalence, precision, population size, and desired power of the survey. In addition, sample sizes to detect FMD if the disease is present and also as proof of freedom were computed. The current FMD active surveillance programs consist of clinical, virological, and serological surveillance. For the 2012 serological surveillance, annual sample sizes (n = 265,065) are planned at four separate levels: statistical (n = 60,884) and targeted (n = 115,232) at breeding pig farms and slaughter house, in together with the detection of structural proteins (SP) antibodies against FMD (n = 88,949). Overall, the sample size was not designed taking the specific aims of each surveillance stream into account. The sample sizes for statistical surveillance, assuming stratified two-stage sampling technique, was based to detect at least one FMD-infected case in the general population. The resulting sample size can be used to obtain evidence of freedom from FMD infection, not for detecting animals that have antibodies against FMD virus non-structural proteins (NSP). Additionally, sample sizes for targeted surveillance were not aimed for the population at risk, and also without consideration of statistical point of view. To at least the author's knowledge, sampling plan for targeted, breeding pig farms and slaughter house is not necessary and need to be included in the part of statistical surveillance. Assuming design prevalence of 10% in an infinite population, a total of 29 animals are required to detect at least one positive with probability of 95%, using perfect diagnostic test system (Se = Sp = 100%). A total of 57,211 animals needed to be sampled to give 95% confidence of estimating SP prevalence of 80% at the individual animal-level with a precision of ${\pm}5%$, assuming 800 herds with an average 200 heads per farm, within-farm variance of 0.2, between-farm variance of 0.05, cost ratio of 100:1 of farm against animals. Furthermore, 779,736 animals were required to demonstrate FMD freedom, and the sample size can further be reduced depending on the parameters assumed.

• Korean Journal of Psychosomatic Medicine
• /
• v.24 no.2
• /
• pp.133-139
• /
• 2016

Objectives : As the prevalence of elderly depression increases, it becomes urgent problem to provide preventive and management measures. But in practice, it is difficult to detect depression in early stage. The purpose of this study is to evaluate the association between sociodemographic factors and depression in elderly welfare facility users in a city. Methods : In this research, the severity of depression and sociodemographic factors(gender, age, education, co-morbid disease, housing type, number of children, number of family members living with the subjects) was evaluated through PHQ-9 and interview. Using the data, the associations of depression and sociodemographic factors were analyzed. Based on PHQ-9 depression cut-off value(10 points), the subjects were divided into two groups, and the difference of the variables between groups were analyzed statistically. Results : 'Own house'(YES/NO), education(less than elementary school graduation/more than elementary school graduation) were sociodemographic factors which showed significance difference in mean PHQ-9 scores. Group with Over PHQ-9 10 points showed less 'having their own house' and less education level than group with less PHQ-9 10 points. Conclusions : With this research, it is expected that the risk factors for the elderly depression can be understood and the measures for early detection and invention of elderly depression would be provided.

• Journal of Preventive Medicine and Public Health
• /
• v.20 no.2 s.22
• /
• pp.312-321
• /
• 1987

To investigate the maternal and child factors associated with early detection of cerebral palsy, 74 mothers of cerebral palsy children who were born since January 1, 1980 and being treated at Taegu Rehabilitation Center for the Handicapped, Rehabilitiation Center of Taegu University, St. Paul Children's House and Pusan Welfare Association of Cerebral Palsy Children were interviewed from February to April 1987. There is no association between age of child when parents noticed the child's abnormality and educational level of father but it tend to be detected earlier when education level of mother is college or above compared with high school or under. There is a trend of earlier detection of child's abnormality although statistically not significant in case father is professional or managerial worker, monthly income of father is over \610,000, child is first-born, age of the parents is 34 years or under, child is a boy, and child has periodic well-baby check-up. The child's abnormality is detected earlier when mothers had 7 prenatal visits or more compared with those who had 6 visits or less (p<0.05). Parents noticed the child's abnormality first in 85.1% of the cases whereas doctors detected it first in 2.7% and this percentage was not different whether the child had periodic well-baby check-up or not. The first physician's diagnosis of the children was cerebral palsy in 36.5% and the rest was normal, need for observation, uncertain, etc. Parents took the child to doctor for diagnosis 2-3 months after they noticed the child's abnormality and after the child was diagnosed as cerebral palsy parents either took no therapeutic measure or brought the child to physiotherapy or acupuncture or gave herb medicine before they started specific rehabilitative therapy. For early detection of the cerebral palsy children, teaching of evaluation method for child development should be reinforced both in medical school and clinical training course and should train the specialist for diagnosis and treatment of crippling conditions. Also, public education is needed for the importance of early detection of crippling conditions and currently available methods for diagnosis and treatment.

• Analytical Science and Technology
• /
• v.29 no.1
• /
• pp.35-42
• /
• 2016

A new nano-composite carbon ink for the development of disposable dopamine (DA) biosensors based on screen-printed carbon electrodes (SPCEs) is introduced. The method developed uses SPCEs coupled with a tyrosinase modified nano-composite carbon ink. The ink was prepared by an “in-house” procedure with reduced graphene oxide (rGO), Pt nanoparticles (PtNP), and carbon materials such as carbon black and graphite. The rGO-PtNP carbon composite ink was used to print the working electrodes of the SPCEs and the reference counter electrodes were printed by using a commercial Ag/AgCl ink. After the construction of nano-composite SPCEs, tyrosinase was immobilized onto the working electrodes by using a biocompatible matrix, chitosan. The composite of nano-materials was characterized by X-ray photoelectron spectroscopy (XPS) and the performance characteristics of the sensors were evaluated by using voltammetric and amperometric techniques. The cyclic voltammetry results indicated that the sensors prepared with the rGO-PtNP-carbon composite ink revealed a significant improvement in electro-catalytic activity to DA compared with the results obtained from bare or only PtNP embedded carbon inks. Optimum experimental parameters such as pH and operating potential were evaluated and calibration curves for dopamine were constructed with the results obtained from a series of amperometric detections at −0.1 V vs. Ag/AgCl. The limit of detection was found to be 14 nM in a linear range of 10 nM to 100 µM of DA, and the sensor’s sensitivity was calculated to be 0.4 µAµM⁻¹cm⁻².

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.68.2-68.2
• /
• 2013

Camera for QUasars in EArly uNiverse (CQUEAN) is an optical CCD camera system made by Center for Exploration of the Origin of the Universe (CEOU). CQUEAN is developed for follow-up observation of red sources such as high-redshift quasar candidates ($z{\geq}5$), gamma-ray bursts (GRB), brown dwarfs and young stellar objects. The CQUEAN is composed of a science camera with deep-depletion CCD chip which is sensitive at around $1{\mu}m$, a set of custom-made wide-band filters for detection of quasar candidates at z~5, and a guide camera. A focal reducer was developed to secure $4.8^{\prime}{\times}4.8^{\prime}$ field of view, and an in-house user software for efficient data acquisition. CQUEAN was attached to 2.1m Otto Struve Telescope in McDonald Observatory, USA, in August 2010. About 1000 quasar candidates including 3 confirmed with follow-up spectroscopy, have been observed so far, and many high-z galaxy cluster candidates, GRBs and supernovae were also observed. And monitoring of HBC 722, a young stellar object, is under way since 2011. Further enhancement of CQUEAN including the introduction of narrow-band filters is planned.