• Advances in nano research
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• v.16 no.4
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• pp.325-340
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• 2024

There are several novel uses for dispersing many nanoparticles into a conventional fluid, including dynamic sealing, damping, heat dissipation, microfluidics, and more. Therefore, melting heat and mass transfer characteristics of a 3-D MHD Hybrid Nanofluid flow over a rotating disc with presenting dufour and soret effects are assessed numerically in this study. In this instance, we investigated both ferric sulfate and molybdenum disulfide as nanoparticles suspended within base fluid water. The governing partial differential equations are transformed into linked higher-order non-linear ordinary differential equations by the local similarity transformation. The collection of these deduced equations is then resolved using a Chebyshev spectral collocation-based algorithm built into the Mathematica software. To demonstrate how different instances of hybrid/ nanofluid are impacted by changes in temperature, velocity, and the distribution of nanoparticle concentration, examples of graphical and numerical data are given. For many values of the material parameters, the computational findings are shown. Simulations conducted for different physical parameters in the model show that adding hybrid nanoparticle to the fluid mixture increases heat transfer in comparison to simple nanofluids. It has been identified that hybrid nanoparticles, as opposed to single-type nanoparticles, need to be taken into consideration to create an effective thermal system. Furthermore, porosity lowers the velocities of simple and hybrid nanofluids in both cases. Additionally, results show that the drag force from skin friction causes the nanoparticle fluid to travel more slowly than the hybrid nanoparticle fluid. The findings also demonstrate that suction factors like magnetic and porosity parameters, as well as nanoparticles, raise the skin friction coefficient. Furthermore, It indicates that the outcomes from different flow scenarios correlate and are in strong agreement with the findings from the published literature. Bar chart depictions are altered by changes in flow rates. Moreover, the results confirm doctors' views to prescribe hybrid nanoparticle and particle nanoparticle contents for achalasia patients and also those who suffer from esophageal stricture and tumors. The results of this study can also be applied to the energy generated by the melting disc surface, which has a variety of industrial uses. These include, but are not limited to, the preparation of semiconductor materials, the solidification of magma, the melting of permafrost, and the refreezing of frozen land.

• Journal of Industrial Convergence
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• v.22 no.7
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• pp.15-21
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• 2024

A hiking stick is generally one of the walking aids that allow hikers to walk while relying on their own bodies when walking. A rechargeable battery must be built into the hiking stick, which is an auxiliary device, in order to perform various functions. A separate power supply is required to charge the rechargeable battery. This study is about a self-generated power supply and develops a power generation device using a screw with higher power generation efficiency than the existing method. It is differentiated from the method suggested in this study by comparing and analyzing it with the existing power generation method, and identifying problems therewith. The screw-type power generation device generates power when the climbing stick comes into contact with the ground and when it is separated from the ground. The built-in power generation device does not require a separate power supply, and it can be used by attaching the role of a mobile phone auxiliary battery and a lighting lamp, and it has the effect of being able to find it through location tracking by embedding a GPS sensor, etc., and using lighting to keep the user safe in emergency situations such as distress. The existing generator with built-in mountain climbing stick is difficult to charge due to very weak current and low practicality, but the generator developed in this research could achieve high efficiency to obtain a sufficient current, so it is possible to charge a battery and practicality.

• Journal of Cardiovascular Imaging
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• v.30 no.4
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• pp.292-304
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• 2022

BACKGROUND: Calcium is a determinant of paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI). This is based on a fixed contrast attenuation value while X-ray attenuation is patient-dependent and without considering frame expansion and PVL location. We examined the role of calcium in (site-specific) PVL after TAVI using a patient-specific contrast attenuation coefficient combined with frame expansion. METHODS: 57 patients were included with baseline CT, post-TAVI transthoracic echocardiography and rotational angiography (R-angio). Calcium load was assessed using a patient-specific contrast attenuation coefficient. Baseline CT and post-TAVI R-angio were fused to assess frame expansion. PVL was assessed by a core lab. RESULTS: Overall, the highest calcium load was at the non-coronary-cusp-region (NCR, 436 mm³) vs. the right-coronary-cusp-region (RCR, 233 mm³) and the left-coronary-cusp-region (LCR, 244 mm³), p < 0.001. Calcium load was higher in patients with vs. without PVL (1,137 vs. 742 mm³, p = 0.012) and was an independent predictor of PVL (odds ratio, 4.83, p = 0.004). PVL was seen most often in the LCR (39% vs. 21% [RCR] and 19% [NCR]). The degree of frame expansion was 71% at the NCR, 70% at the RCR and 74% at the LCR without difference between patients with or without PVL. CONCLUSIONS: Calcium load was higher in patients with PVL and was an independent predictor of PVL. While calcium was predominantly seen at the NCR, PVL was most often at the LCR. These findings indicate that in addition to calcium, specific anatomic features play a role in PVL after TAVI.

• The Korean Journal of Quaternary Research
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• v.33 no.1_2
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• pp.37-48
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• 2021

The cold surge is an important extreme weather in East Asia during winter, and is largely affected by behavior of the Siberian high Arctic Oscillation, which represents undulation of large-scale pressure pattern in the Arctic region. Recent studies also revealed that the synoptic low pressure system developing in the eastern boundary of the Asian continent is sensitive to sea surface temperature (SST) and plays an important role in strengthening the cold advection over the Korean Peninsula during cold surges. In this study, we analyzed the Arctic Oscillation affecting the large-scale background of cold surge in East Asia, and the sea surface temperature in the coast of East Asia is examined focusing on its role on synoptic low-inducing cold advection. For the analysis, the days with the bottom 3% of the average daily temperature, measured at five surface stations in Korean Peninsula during 49 years (1969/70-2017/18), were used for the cold surge cases. During the negative phase of the Arctic Oscillation, a strong trough is observed over East Asia, and the inflow of cold air from the polar region is strengthened, which lead to frequent cold surges. In addition, anomalously high SST in the eastern coast of Asia increases sensible and latent heat release from the ocean, therefore, it enlarges the likelihood of synoptic low-inducing extreme cold surges.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.4
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• pp.129-137
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• 2024

An analytic solution for the interaction between an array of circular piles made by joining trapezoid steel pipes (TSP) and waves was obtained using an eigenfunction expansion method. First, an analytic model for the wave scattering of multiple piles fixed at arbitrary positions was derived, and then a simplified model was obtained assuming that an infinite array of identical piles were deployed perpendicular to the propagating direc- tion of incident waves. A regular wave experiment was conducted using an experimental model with a scale ratio of 1/100 in a two-dimensional wave tank to verify the analytic solutions. The analytic results and experimental results were qualitatively consistent with each other. Using a developed analytic model, we examined the wave force on the multiple piles and the wave deformation in front of the arrayed piles. The period for the installation is greatly reduced as the TSP pile can be prefabricated in a factory. In particular, it is possible to install at the soft seabed. A seawall structure using arrayed TSP piles will be an ideal complement for a concrete seawall in future.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.2
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• pp.99-105
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• 1986

This study was carried out to compare the soil profile development indices of Sinjeong series according to the distribution areas in Yeongnam district. The results obtained were as follows; 1. The soils studied were belong to fine loamy family of hilly residual soils derived from conglomerate. These soils were well drained and dominantly had 30-60% slopes, and used for forest. 2. The surfaces were typified by brownish red (5YR) or brownish yellow (10YR) loam, subsoils were clay loam of reddish brown (5YR) or reddish yellow (7.5YR) and the substrata were in dark reddish brown (5YR) or pink (7.5YR) sandy loam. 3. The indices of horizon development of the soils studied were from 0.18 to 0.38 and the index in illuvial horizons with clay films were over 0.36, that were higher than the others. The profile development indices were similar to each other ranging from 30.18 to 35.93. 4. Positive correlations were observed among horizon development indices and normalized values of structure, texture and consistences, but the relationship between profile development indices and consistences were not the same. 5. The amount of clay minerals formed in the soil horizons per 100g of parent materials were 1.1-1.6g and the rates of the clay leached were around 4.4-5.9%. 6. The sphericity and roundness of the gravels contained in the soils studied were 0.741 and 0.715, respectively. These similarity of "well rounded" gravels certify that the parent rocks were formed under similar environments.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.217-225
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• 2007

This study was conducted to estimate the general genetic parameters, heritabilities, and genetic and phenotypic correlations on growth-related traits by studying multiple trait animal model in two Korean abalone species, Haliotis discus hannai and H. discus discus. The data was collected from the records of 3,795 individuals produced from 54 sires and 74 dams in Haliotis discus hannai and 399 individuals produced from 7 sires and 7 dams in Haliotis discus discus. The data was evaluated by the Genetics and Breeding Research Center, National Fisheries Research & Development Institute (NFRDI). Genetic parameters were estimated for two abalone species raised in Bukjeju branch, NFRDI, from May 20 to November 1, 2004. The heritability estimates for growth traits of shell length, shell width and body weight obtained from restricted maximum likelihood (REML) were ranging from 0.73 to 0.78 in Haliotis discus hannai, and from 0.87 to 0.89 in H. discus discus. The heritabilities for shell shape and condition factor were ranging from 0.17 to 0.20 in Haliotis discus hannai, and from 0.01 to 0.45 in H. discus discus. Genetic and phenotypic correlations were over than 0.96 between shell parameters and weight in both of abalone subspecies, indicating that breeding for weight gains could successfully be achieved by selecting for shell length.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.47-54
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• 2007

Purpose : Viral respiratory tract infection is most common cause for admission to hospital in children. There are many cases with elevated transaminase level in patients with viral lower respiratory tract infection (LRTI). The aim of this study was to compare indexes of disease severity such as duration of assisted ventilation, length of hospital stay and Respiratory Distress Assessment Instrument (RDAI) score in children with viral LRTI with and without elevated transaminase levels and to determine the etiology related to elevated transaminase levels in this patients group. Methods : Virological analysis was done from respiratory specimens obtained from patients with LRTI admitted to Kangnam Sacred Heart Hospital from Jan. 2003 to Jun. 2005. Viral diagnosis was made by isolation of viruses employing HEp-2 cell culture from nasopharyngeal aspiration. Medical records of children were reviewed retrospectively. We compared age, sex, RDAI score, Respiratory Rate (RR) score and mean duration of hospital stay between patients with elevated transaminase levels (Patient Group) and patients with normal transaminase levels (Control Group). Results : Viruses were isolated from 181 children with LRTI. 16 cases were excluded according to criteria. 28 cases (17.0%) had elevated transaminase levels (Patient group) and 137 cases (83.0%) had normal transaminase levels (Control group). There were no significant difference in duration of fever, RR score, RDAI score, incidence of $O_2$ inhalation and duration of hospital stay between patient group and control group. We found 17 (60.7%) cases of RSV, 4 cases (14.3%) of parainfluenza, 4 cases (14.3%) of influenza B virus, 3 cases (10.7%) of adenovirus and 1 case (3.6%) of influenza A virus infection in patient group and 78 cases (56.9%) of RSV, 28 cases (20.4%) of parainfluenza virus, 13 cases (9.5%) of influenza A virus, 9 cases (6.6%) of influenza B virus, 6 cases (4.4%) of adenovirus and 3 cases (2.2%) of coxsackie virus infection in control group. Conclusion : There were 28 cases (17.0%) with elevated transaminase level among patients with virus isolated LRTI. There was no relation between elevated transaminase level and severity of disease. The viral etiologies in two groups were not significantly different. There was no significant difference of age distribution between two groups.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.205-214
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• 2000

Recently, the magnetic force has been considered as a method for a more efficient tooth movement. The purpose of this study was to evaluate the effects of different static magnetic fields of Nd-Fe-B magnet on MC3T3-E1 cells by measuring the alkaline phosphatase activity and observing the amount of stained alkaline phosphatase. For measuring of alkaline phosphatase activity, MC3T3-E1 cells were seeded in first and third row of 12 well culture plates. And Nd-Fe-B magnets were positioned under the first column of first and third row to apply different static magnetic fields(first column:100mT ; second column:4.6mT ; third column:0.5mT ; forth column:0.0mT) to the cells for 7, 13, 19, and 25 days. For staining of alkaline phosphatase, MC3T3-E1 cells were seeded in 100mm culture plates. And Nd-Fe-B magnets were positioned under the corner of plates to apply different static magnetic fields(magnet side:100mT : the opposite side:0.5mT) to the cells for 7, 13, 19, and 25 days. The results were as follows : 1. ALP activity was increased until day 19 in biochemical determination as well as in histochemical staining, 2. The application of higher magnetic field(100mT) suppressed ALP activity at day 13, 19, 25. On the contrary, the application of the lower magnetic field(4.6mT, 0.5mT) significantly enhanced the ALP activity. 3. Consistent with enzyme assay, histochemical staining of ALP also demonstrated that higher magnetic field(100mT) suppressed ALP activity, lower one(0.5mT) enhanced.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.462-471
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• 1997

Effect of citron on Dongchimi (watery radish kimchi) fermentation was investigated by sensory evaluation and the measurement of non-volatile organic acids, soluble pectin, and the texture during fermentation up to 36 days. Dongchimi with various levels of citron (0, 1, 2, 4, 6％) was fermented at 10$^{\circ}C$. In sensory evaluation, citron-added Dongchimi showed the higher scores in most characteristics than Dongchimi without citron in which Dongchimi with 2％ citron was the most preferable. The non-volatile organic acids of Dongchimi were identified as lactic acid, oxalic acid, succinic acid, malic acid, and citric acid. There were significant changes in the contents of lactic acid, succinic acid, malic acid, and citric acid during fermentation. Generally, the content of hydrochloric acid-soluble pectin (HSP) of Dongchimi occupied the higher ratio in the total soluble pectin content. Generally, the content of hot water-soluble pectin (HWSP) of Dongchimi decreased and that of sodium hexametaphosphate-soluble pectin (NaSP) increased during fermentation. The hardness of radish in Dongchimi showed the highest score on 23$\^$rd/ day and decreased thereafter.