• Parasites, Hosts and Diseases
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• v.57 no.4
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• pp.423-427
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• 2019

Coenurosis is an important zoonotic helminthic disease caused by the larval stage of the tapeworm Taenia multiceps. This parasite typically infects the brain of the intermediate hosts, including sheep, goat, cattle and even humans. We report a case of T. multiceps infection in a yak confirmed by clinical symptoms, morphological characteristics, and molecular and phylogenetic analyses. The coenurus was thin-walled, whitish, and spherical in shape with a diameter of 10 cm. The parasite species was identified as T. multiceps by PCR amplification and sequencing of the 18S rRNA, cox1 and nad1 genes. Three gene sequences all showed high homology (all above 97%) with the reference sequences from different hosts. Moreover, phylogenetic reconstructions with the 3 published Taenia gene sequences confirmed that the Qinghai yak isolate was closely related to T. multiceps. Although there are advanced diagnosis and treatment methods for coenurosis, early infection is difficult to diagnose. Importantly, the findings of yak infection case should not be ignored due to its zoonotic potential.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.186-197
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• 2019

Purpose: This study intends to develop a nonlinear cyclic plasticity damage model in the framework of finite element formulation, which is capable of taking large deformation effects into account, in order to accurately predict the hysteretic behavior of stainless steel structures. Method: The new cyclic constitutive equations that utilize the combined isotropic-kinematic hardening rule for plastic deformation is incorporated into the damage mechanic model in conjunction with the large strain formulation. The damage growth law is based on the experimental observations that the evolution of microvoids yields nonlinear damage accumulation with plastic deformation. The damage model parameters and the procedure for their identification are presented. Results and Conclusion: The proposed nonlinear damage model has been verified by simulating uniaxial strain-controlled monotonic and cyclic loading tests, and successfully applied to a thin-walled stainless steel pipe subjected to constant and alternating strain-controlled cyclic loadings.

• Mycobiology
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• v.48 no.6
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• pp.450-463
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• 2020

The strains 17E-042, 17E-039, and NC13-171 belong to Ascomycota and were isolated from soil collected from Sancheong-gun and Yeongam-gun, Korea. The strain 17E-042 produced white mycelial colonies that developed a sienna color with a round margin on potato dextrose agar (PDA), and the reverse side developed a light sienna color. Morphologically, this strain was similar to the strains of Arthrinium phragmites and A. hydei, but the shorter conidial size of the newly identified strain (17E-042) was distinct. The strain 17E-039 produced macroconidia that were pale yellow to orange-brown, elongated-ellipsoid to oblong, round at both ends, primarily straight but sometimes slightly curved, 0-septate, thin-walled, and filled with numerous droplets, having diameters of 20.4-34.3 × 8.0-12.0 ㎛. And the strain NC13-171 formed hyaline to light brown chlamydospores, solitary or in a chain. Multigene phylogenetic analyses were conducted using sequence data obtained from internal transcribed spacer (ITS) regions, 28S rDNA large subunit (LSU), β-tubulin (TUB2), translation elongation factor 1-alpha (TEF1-α), and RNA polymerase II large subunit (RPB2) genes. The results of molecular phylogeny, the detailed descriptions and illustrations of each species strongly support our proposal that these strains from soil in Korea be designated as Arthrinium minutisporum sp. nov. and two new records of Pezicula neosporulosa and Acrocalymma pterocarpi.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.1
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• pp.1-11
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• 2021

Thermal protection system structures such as double-panel structures are used on the skin of the fuselage and wings to prevent the transfer of high heat into the interior of an high supersonic/hypersonic aircraft. The thin-walled double-panel skin can be exposed to acoustic loads by high power engine noise and jet flow noise, which can cause sonic fatigue damage. In order to predict the fatigue life of the skin, the octave bandwidth SPL should be calculated as narrow bandwidth PSD or acoustic load history using interpolation method. In this paper, a method of converting the octave bandwidth SPL acoustic load into a narrow bandwidth PSD and reconstructed acoustic load history was investigated. The octave bandwidth SPL was converted to the narrow bandwidth PSD using various interpolation methods such as flat, log and linear scale, and the probabilistic characteristics and fatigue damage results were compared. It was found that average error of fatigue damage index by the log scale interpolation method was relatively small among three methods.

• Advances in nano research
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• v.11 no.6
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• pp.581-593
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• 2021

This model is proposed to describe the buckling behavior of Carbon Nanotubes (CNTs) embedded in an elastic medium taking into account the combined effects of the magnetic field, the temperature, the nonlocal parameter, the number of walls. Using Eringen's nonlocal elasticity theory, thin cylindrical shell theory and Van der Waal force (VdW) interactions, we develop a system of partial differential equations governing the buckling response of CNTs embedded on Winkler, Pasternak, and Kerr foundations in a thermal-magnetic environment. The pre-buckling stresses are obtained by applying airy's stress function and an adjacent equilibrium criterion. To estimate the nonlocal critical buckling load of CNTs under the simultaneous effects of the magnetic field, the temperature change, and the number of walls, an optimization technique is proposed. Furthermore, analytical formulas are developed to obtain the buckling behavior of SWCNTs embedded in an elastic medium without taking into account the effects of the nonlocal parameter. These formulas take into account VdW interactions between adjacent tubes and the effect of terms involving differences in tube radii generally neglected in the derived expressions of the critical buckling load published in the literature. Most scientific research on modeling the effects of magnetic fields is based on beam theories, this motivation pushes me to develop a cylindrical shell model for studying the effect of the magnetic field on the static behavior of CNTs. The results show that the magnetic field has significant effects on the static behavior of CNTs and can lead to slow buckling. On the other hand, thermal effects reduce the critical buckling load. The findings in this work can help us design of CNTs for various applications (e.g. structural, electrical, mechanical and biological applications) in a thermal and magnetic environment.

• Advances in materials Research
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• v.12 no.3
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• pp.243-261
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• 2023

This study aims to analyze the mechanical buckling behavior of a single-walled carbon nanotube (SWCNT) integrated with a one-parameter elastic medium and modeled as a Kerr-type foundation under a longitudinal magnetic field. The structure is considered homogeneous and therefore modeled utilizing the nonlocal first shear deformation theory (NL-FSDT). This model targets thin and thick structures and considers the effect of the transverse shear deformation and small-scale effect. The Kerr model describes the elastic matrix, which takes into account the transverse shear strain and normal pressure. Using the nonlocal elastic theory and taking into account the Lorentz magnetic force acquired from Maxwell relations, the stability equation for buckling analysis of a simply supported SWCNT under a longitudinal magnetic field is obtained. Moreover, the mechanical buckling load behavior with respect to the impacts of the magnetic field and the elastic medium parameters considering the nonlocal parameter, the rotary inertia, and transverse shear deformation was examined and discussed. This study showed useful results that can be used for the design of nano-transistors that use the buckling properties of single-wall carbon nanotubes(CNTs) due to the creation of the magnetic field effect.

• Nuclear Engineering and Technology
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• v.20 no.3
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• pp.170-178
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• 1988

An automated ultrasonic flaw detection system was developed for thin-walled and short tubes such as Zircaloy-4 tubes used for cladding heavy-water reactor fuel. The system was based on the two channels immersion pulse-echo technique using 14 MHz shear wave and the specially developed helical scanning technique, in which the tube to be tested is only rotated and the small water tank with spherical focus ultrasonic transducers is translated along the tube length. The optimum angle of incidence of ultrasonic beam was 26 degrees, at which the inside and outside surface defects with the same size and direction could be detected with the same sensitivity. The maximum permissible defects in the Zircaloy-4 tubes, i.e., the longitudinal and circumferential v notches with the length of 0.76mm and 0.38mm, respectively and the depth of 0.04 mm on the inside and outside surface, could be easily detected by the system with the inspection speed of about 1 m/min and the very excellent reproducibility. The ratio of signal to noise was greater than 20 dB for the longitudinal defects and 12 dB for the circumferential defects.

• Advances in concrete construction
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• v.15 no.4
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• pp.251-267
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• 2023

In this paper, an experimental investigation is carried out to assess the inherent self-compacting properties of geopolymer mortar and its impact on flexural strength of thin-walled ferro-geopolymer box beam. The inherent self-compacting properties of the optimal mix of normal geopolymer mortar was studied and compared with self-compacting cement mortar. To assess the flexural strength of box beams, a total of 3 box beams of size 1500 mm × 200 mm × 150 mm consisting of one ferro-cement box beam having a wall thickness of 40 mm utilizing self-compacting cement mortar and two ferro-geopolymer box beams with geopolymer mortar by varying the wall thickness between 40 mm and 50 mm were moulded. The ferro-cement box beam was cured in water and ferro-geopolymer box beams were cured in heat chamber at 75℃ - 80℃ for 24 hours. After curing, the specimens are subjected to flexural testing by applying load at one-third points. The result shows that the ultimate load carrying capacity of ferro-geopolymer and ferro-cement box beams are almost equal. In addition, the stiffness of the ferro-geoploymer box beam is reduced by 18.50% when compared to ferro-cement box beam. Simultaneously, the ductility index and energy absorption capacity are increased by 88.24% and 30.15%, respectively. It is also observed that the load carrying capacity and stiffness of ferro-geopolymer box beams decreases when the wall thickness is increased. At the same time, the ductility and energy absorption capacity increased by 17.50% and 8.25%, respectively. Moreover, all of the examined beams displayed a shear failure pattern.

• Design & Manufacturing
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• v.17 no.4
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• pp.63-71
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• 2023

In order to increase the extrusion production speed of aluminum, extrusion die cooling technology using liquid nitrogen has recently attracted a lot of attention. Increasing the extrusion speed increases the temperature of the bearing area of extrusion dies and the extrusion profile, which may cause defects on the surface of extruded profile. Extrusion die cooling technology is to directly inject liquid nitrogen through a cooling channel formed between the die and the backer inside the die-set. The liquid nitrogen removes heat from the die-set, and gaseous nitrogen at the exit of the channel, covers the extrusion profile of an inert atmosphere reducing the oxidation and the profile temperature. The aim of this study is to evaluate the cooling capacity by applying die cooling to extrusion of Al-Mn-based aluminum alloy flat tubes, and to investigate the effects of die cooling on the change in extrusion characteristics of flat tubes. Cooling capacity was confirmed by observing the temperature change of the extrusion profile depending on whether or not die cooling is applied. To observe changes in material characteristics due to die cooling, surface observation is conducted and microstructure and precipitate analysis are performed by FE-SEM on the surface and longitudinal cross section of the extruded flat tubes.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.171-178
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• 2008

We have found the clusters of tiny spiny puffball-like mushrooms growing gregariously in fairy ring (arcs) rimmed by a zone of darker green grass in the golf courses. Macroscopic as well as microscopic characters were examined for the morphology of fruiting body. Exoperidium is thin and densely spiny with minute fibrillae at early stage. The connivent spines were soft and quite persistent. In age, the fibrillae scrumble away with a powdery coating, which leaves white endoperidium becoming pale brown. It's interior was white and fleshy at first, but turns into an olive-colored dust as the gleba, the spore-producing tissue, develops to maturity and loaded with olive-brown spore mass. Then, distinct apical pore developed on the endoperidium. Rudimentary subgleba(sterile base) was narrow, chambered, delineated from the gleba by a membrane in young material. These characters suggested this fungus is a Vascellum, a member of the family Lycoperdaceae. The shapes of the spores were globose, echinulate, $3{\sim}3.5{\mu}m$ in diameter, thick-walled, and olive brown. Capillitial threads were $8-9{\mu}m$ wide, mostly colorless in KOH solution and thin-walled, which designated as "paracapillitium". This is an another character that distinguishes this mushroom from Lycoperdon spp. The spines developed on exoperidium were characteristically connivent; their apices joined together in a point, leaving a space below, which gives the appearance of vault to each group of usually 5 to 6 fibrillae. Based on the above characters, this fungus is identified as Vascellum curtisii (Berkeley). The characters distinguishable this from Lycoperdon pulcherrimum, and Vascellum pretense are discussed in detail. Control trial was also attempted. Strong vertical raking(SVR) followed by applying 500x detergent solution (Spark, Aekyung Co. Seoul) resulted in excellent control over any other treatments. In this plot, fruiting body was not developed throughout the end of mushroom growing season.