• Journal of computational fluids engineering
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• v.14 no.4
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• pp.101-108
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• 2009

We present a new finite-element scheme for direct numerical simulation of particle suspensions in simple shear flow of a viscoelastic fluid in 3D. The sliding tri-periodic representative cell concept has been combined with DEVSS/DG finite element scheme by introducing constraint equations along the domain boundary. Rigid body motion of the freely suspended particle is described by the rigid-shell description and implemented by Lagrangian multipliers on particle boundaries. We present the bulk rheology of suspensions through the numerical examples of single-, two- and many-particle problems, which represent a large number of such systems in simple shear flow. We report the steady bulk viscosity and the first normal stress coefficient, which show shear-thickening behavior for both properties.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.89-103
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• 2012

In this study, the stability of laminated homogeneous and non-homogeneous orthotropic truncated conical shells with freely supported edges under a uniform hydrostatic pressure is investigated. It is assumed that the composite material is orthotropic and the material properties depend only on the thickness coordinate. The basic relations, the modified Donnell type stability and compatibility equations have been obtained for laminated non-homogeneous orthotropic truncated conical shells. Applying Galerkin method to the foregoing equations, the expression for the critical hydrostatic pressure is obtained. The appropriate formulas for the single-layer and laminated, cylindrical and complete conical shells made of homogeneous and non-homogeneous, orthotropic and isotropic materials are found as a special case. Finally, effects of non-homogeneity, number and ordering of layers and variations of shell characteristics on the critical hydrostatic pressure are investigated.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.1
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• pp.13-19
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• 1998

We have calculated the electronic structure of impurity atoms in metal host by using the tight binding model in the recursion method. For a self-consistent calculation, we assumed that the effect of impurity introduction was localized only at the impurity site and its neighbours. We calculated the Madelung term by limiting the contribution to Vm of the charge perturbations to the first shell around the impurity with Evjen technique. The calculated local density of states and charge transfer values have been compared with the experimental values for a single impurity in metal host. We fund that d-reso-nance state came from the repulsive interaction between impurity d-state and host band, and the position of d-resonance state depended on the difference of valence electrons between the host and the impurity. the results also showed that the charge transfer value between an impurity and host metal was comparable to the ionicity difference between them.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.56-60
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• 2002

After many casualties with conventional bulk carriers in recent years, double hull bulk carrier was proposed ta enhance the structural safety of side shell and transverse bulkhead. In this paper, two alternative structural designs of double hull bulk camel were executed based an the Lloyd's rule, and the results were examined in comparison with the existing single hull bulk carrier in the viewpoints of the increase of weight and construction cost. The relative construction concept was used to certify the economical validity of double hull bulk carrier.

• Animal Systematics, Evolution and Diversity
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• v.34 no.4
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• pp.215-219
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• 2018

Protochitonidae Ashby, 1925 is a family of small to medium sized chitons that includes a single fossil genus and two extant genera. Of the two extant genera, Deshayesiella Carpenter in Dall, 1879 contains 5 described species. Although most Deshayesiella species are known to be found in deep sea habitats(over 100 m), D. curvata (Carpenter in Pilsbry, 1892) is found from shallow waters(1-20 m). In this study, we provide details of microstructure of shell and radula characters using scanning electron microscopy and morphological features of D. curvata, and its partial sequence of mitochondrial DNA cox1 gene as DNA barcode sequence. In addition, we compare morphological differences of D. curvata from other congeneric species.

• Advances in nano research
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• v.10 no.2
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• pp.165-174
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• 2021

This paper based on Sanders theory aims to investigate the vibration of SWCNTs considering the clamped-simply supported, clamped-free, clamped-clamped and simply supported-simply supported end conditions. After developing the governing equation of the objective system, the Rayleigh-Ritz technique is implemented for the purpose of obtaining the frequency equation in the eigen form. In addition, the applicability of this model for the analysis of vibration of CNTs is examined with the effect of length and ratio of height-to-radius. A detailed description of different types of SWCNTs with different indices is provided in the theoretical methodology. The effect of extended length is stimulated with increasing the radii and the model is effective because it also predicts the effect of thickness on vibration of SWCNTs. For different boundary conditions, the present results are verified with earlier literature.

• Journal of Ceramic Processing Research
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• v.13 no.spc1
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• pp.59-63
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• 2012

Ga2O3-core/CdO-shell nanowires were synthesized by a two step process comprising thermal evaporation of GaN powders and sputter-deposition of CdO. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that the cores and the shells of the annealed coaxial nanowires were single crystal of monoclinic Ga2O3 and FCC CdO, respectively. As-synthesized Ga2O3 nanowires showed a broad emission band at approximately 460 nm in the blue region. The blue emission intensity of the Ga2O3 nanowires was slightly decreased by CdO coating, but it was significantly increased by subsequent thermal annealing in a reducing atmosphere. The major emission peak was also shifted from ~500 nm by annealing in a reducing atmosphere, which is attributed to the increases in the Cd interstitial and O vacancy concentrations in the cores.

• Structural Engineering and Mechanics
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• v.88 no.2
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• pp.109-115
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• 2023

In this paper, frequencies of zigzag structure of carbon nanotubes isinvestigated based on Donnell shell theory. These tubes are wrapped with the ring supports in the axial direction. The fundamental frequency curves displayed in article show the dependence of vibrations attributes to zigzag single walled carbon nanotubes. Various zigzag indices are introduced against the variation of length to predict the vibration. Also, the influence of ring supports is sketched with proposed structure for frequency analysis. The frequencies of zigzag tube decreases as the length increases. It is observed that the frequencies decreases with ring support and have higher frequencies without ring. The problem is formulated using Partial Differential Equation. Three expressions of modal deformation displacement functions is used for the elimination of temporal variation to form the solution in the eigen from. For the stability of present study the results are compared with experimentally and numerically in the open text.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.175-182
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• 2002

A new high yielding mulberry genotype, Victory-1 (V-1) was recommended to the field for irrigated areas by Central Sericultural Research and Training Institute (CSRTI), Mysore during 1996-1997. As K-2 and S-36 mulberry genotypes are already in the field, a study on the comparative performance of V-1, 5-36 and K-2 varieties, in terms of leaf yield, yield attributes, leaf moisture and moisture retaining capacity and their impact on silkworm rearing was carried out under Telangana conditions of Andhra Pradesh during 1999-2001. Among the three genotypes the leaf yield was found to be significantly (P < 0.01) higher in V-1 (64,130 kg/ha/yr) followed by S-36 (44,064 kg/ha/yr) and K-2 (23,990 kg/ha/yr). The maximum leaf moisture was also observed in V-1 (71.84%) compared to S-36 (66.86%) and K-2 (64%). The moisture retaining ability was more in V-1 (70.17%) followed by S-36 (66.20%) and K-2 (60.08%). The yield attributes were found to be significantly (P < 0.01) enhanced in V-1 over S-36 and K-2. Silkworm rearing results (bioassay) indicated a significant (P < 0.01) reduction in larval duration and improvement in larval weight, effective rate of rearing by number and weight, single cocoon and shell weights and shell ratio in the silkworm lots fed on V-1 variety followed by S-36 and K-2. Hence, in this study, V-1 was found to be superior among the three varieties studied.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.361-369
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• 2011

The effect of an increase in the temperature of inlet air on the performance of a membrane humidifier for a PEMFC (Polymer Electrolyte Membrane Fuel Cell) vehicle was investigated both experimentally and numerically. A shell-and-tube type gas-to-gas humidifier with Nafion membrane was tested. The experimental result showed that water transfer varies nonlinearly with the temperature elevation. Numerical analysis based on detailed modeling was also conducted in simplified geometry of a single tube to explain this nonlinear behavior. The simulation revealed that the local water flux varies nonlinearly and dramatically along the tube. The analysis was based on the inverse relationship between the increase in temperature and decrease in relative humidity, both of which seriously affect the water conductivity of the membrane.