• Structural Engineering and Mechanics
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• v.86 no.4
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• pp.519-533
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• 2023

This work focuses on the dynamic analysis of thermal barrier coated straight and curved turbine blades modelled as functionally graded sandwich panel under thermal environment. The pre- twisted straight/curved blade model is considered to be fixed to the hub and, the complete assembly of the hub and blade are assumed to be rotating. The functionally graded sandwich composite blade is comprised of functionally graded face-sheet material and metal alloy core. The constituents' material properties are assumed to be temperature-dependent, however, the overall properties are evaluated using Voigt's micromechanical scheme in conjunction with the modified power-law functions. The blade model kinematics is based on the equivalent single-layer shear deformation theory. The equations of motion are derived using the extended Hamilton's principle by including the effect of centrifugal forces, and further solved via 2D- isoparametric finite element approximations. The mesh refinement and validation tests are performed to illustrate the stability and accurateness of the present model. In addition, frequency characteristics of the pre-twisted rotating sandwich blades are computed under thermal environment at various sets of parametric conditions such as twist angles, thickness ratios, aspect ratios, layer thickness ratios, volume fractions, rotational velocity and blade curvatures which can be further useful for designing the blade type structures under turbine operating conditions.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.51-62
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• 1993

A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

• Journal of the Society of Disaster Information
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• v.15 no.4
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• pp.524-530
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• 2019

Purpose: In this paper, we construct a detailed three-dimensional interface element using a three-dimensional analysis program, and evaluate the composite behavior stability of the connector by applying physical properties such as the characteristics of general members and those of reinforced members Method: The analytical model uses solid elements, including non-linear material behavior, to complete the modeling of beam structures, circular flanges, bolting systems, etc. to the same dimensions as the design drawing, with each member assembled into one composite behavior linkage. In order to more effectively control the uniformity and mesh generation of other element type contact surfaces, the partitioning was performed. Modeled with 50 carbon steel materials. Results: It shows the displacement, deformation, and stress state of each load stage by the contact adjoining part, load loading part, fixed end part, and vulnerable anticipated part by member, and after displacement, deformation, The effect of the stress distribution was verified and the validity of the design was verified. Conclusion: Therefore, if the design support of the micro pile is determined based on this result, it is possible to identify the Vulnerable Parts of the composite behavior connector and the degree of reinforcement.

• The Journal of Korean Medicine
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• v.31 no.3
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• pp.17-27
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• 2010

Objectives: Cocaine has been well known as a representative drug of abuse for its strong reinforcing effect linked to the mesolimbic reward system including dopamine, and such reinforcement leads to the addiction. Acupuncture has been used widely in eastern Asia for the treatment of various diseases including mental disorders and psychiatric problems, and is gathering more interest as one of the complementary and alternative medicines in western countries. In a previous study, we demonstrated that acupuncture at HT7 could affect dopamine release in the mesolimbic system of rats sensitized to alcohol and morphine. This study was designed to investigate whether acupuncture at HT7 could attenuate cocaine intake or not. Material & Methods: Male Sprague-Dawley rats weighing 270-300 g at the start of experiment were trained to self-administer food pellets under a fixed ratio 1 schedule. After the success of acquisition of 100 pellets within 3 h for 3 consecutive days, animals were subjected to surgery whereby Silastic tubing was implanted into right jugular vein and secured with mesh under the anesthetization using pentobarbital injection (50 mg/kg, i.p.). Following recovery, rats were trained to self-administer cocaine (0.25 mg/kg) in daily 2 h sessions under fixed ratio 1 schedule over 10 days. Each treatment was performed on the next day of each establishment of baseline. Results: Results show that acupuncture at HT7, but not at control points, reduced cocaine intake significantly. Acupuncture at HT7 decreased selectively active lever response from $63.15{\pm}3.35$ to $51.46{\pm}3.99$ corresponding $82.12{\pm}5.31%$ compared to basal level. Also, it was demonstrated that the effect of acupuncture was mainly occurred at the half period. Nevertheless, acupuncture at HT7 did not influence the food taking behavior. Conclusions: From the results of this study, it may be suggested that acupuncture at HT7, at least in part, could contribute to the treatment of cocaine abuse.

• Korea-Australia Rheology Journal
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• v.19 no.4
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• pp.233-242
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• 2007

We performed a numerical investigation to find out the optimal choice of the spatial discretization in the distributed-Lagrangian-multiplier/fictitious-domain (DLM/FD) method for the solid/fluid interaction problem. The elastic solid bar attached on the bottom in a pressure-driven channel flow of a Newtonian fluid was selected as a model problem. Our formulation is based on the scheme of Yu (2005) for the interaction between flexible bodies and fluid. A fixed regular rectangular discretization was applied for the description of solid and fluid domain by using the fictitious domain concept. The hydrodynamic interaction between solid and fluid was treated implicitly by the distributed Lagrangian multiplier method. Considering a simplified problem of the Stokes flow and the linearized elasticity, two numerical factors were investigated to clarify their effects and to find the optimum condition: the distribution of Lagrangian multipliers and the solid/fluid interfacial condition. The robustness of this method was verified through the mesh convergence and a pseudo-time step test. We found that the fluid stress in a fictitious solid domain can be neglected and that the Lagrangian multipliers are better to be applied on the entire solid domain. These results will be used to extend our study to systems of elastic particle in the Stokes flow, and of particles in the viscoelastic fluid.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.510-518
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• 1989

Most of orange peels are disposed from orange juice manufacturing process. Thus, our purpose is to utilize these orange peels as fermentation substrate. We have investigated culture conditions and factors influencing citric acid production by an isolated strain, Asp. niger. Citric acid production was much higher in semisolid culture than in submerged culture and the particle size of ground orange peels was favored at 20 mesh in semisolid culture. The optimal pH and temperature were 4.5-5.0 and 3$0^{\circ}C$ respectively and the temperature cycling at 35$^{\circ}C$ for 20 hrs durig exponential phase, 1$0^{\circ}C$ for 4 hrs and 3$0^{\circ}C$ during stationary phase showed higher citric acid production than did at fixed temperature, 3$0^{\circ}C$. The addition of NH$_4$NO$_3$0.2%, MgSO$_4$7$H_2O$ 0.1%, methanol 2.5%, ethanol 1.5%, to culture medium promoted citric acid production but the addition of trace metal ions as nutrients had not effect on the acid production in orange peel medium. Under the optimal culture conditions, maximum yield of citric acid was 80.4% in solid medium. Almost of all original components of citrus peel was consumed by Asp. niger during fermentation.

• Ocean and Polar Research
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• v.26 no.2
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• pp.367-376
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• 2004

Macrobenthos were collected at 7 stations located from $5^{\circ}N$ to $10^{\circ}N$ with 1o interval along the longitude of $131^{\circ}W$ using a box corer with sampling area of $0.25\;m^2$ in July, 1999. In order to see the vertical distribution of macrobenthos in sediments, each subcore sample was divided into 5 layers with 1 cm interval up to 6 cm depth. Each subcore sample was sieved through 0.3 mm mesh screen and fixed with 10% Rose Bengal added formalin. A total of 22 faunal groups in 11 phyla were sampled and the average density was $959\;{\pm}\;584\;ind./m^2$. Foraminiferans comprised 34.8% of total specimens were the most abundant fauna, and followed by nematodes (27.5%), polychaete worms (15.7%), and benthic harpactoid copepods (10.4%). A latitudinal trend was shown in the distribution of macrobenthos; the maximum density of $1,832\;ind./m^2$ appeared at station N06 and the most poverished community occurred at station N09 with the density of $248\;ind./m^2$. The density of typical macrofaunal taxa except foraminiferans and nematods was $116\;ind./m^2$. In the vertical distribution of macrobenthos, more than 70% of macrobenthos occurred in the upper 2 cm layer, and upper 4 cm layer contained about 90% of macrofauna. Polychaete worms consisted of 22 families, and cirratulid and paraonid worms were dominant polychaete species. The prominant feeding guilds of polychaete worms were SDT (surface, descretely motile, tenaculate feeding) and SMX (surface, motile, non-jawed); they comprised more than 50% of polychaete abundance. These feeding guilds of polychaete worms suggests that the deep sea benthos should be well adapted the newly settled deposits from water column, but this should be clarified by the further studies.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.567-574
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• 2012

In this paper, we propose a buffering scheme to improve the performance by adaptively adjusting the length of the buffering period according to the degree of data duplication among peers that belong to each specific playback period in P2P live streaming systems. To do so, we first assign all the peers into many groups depending on their playback time positions. We then determine the length of their buffering periods according to the number of peers belonging to each group. That is, we increase the length of the buffering periods when much buffered data are duplicated among peers within a group while we decrease it when few buffered data are duplicated. By simulation experiments, we show that our proposed buffering scheme can improve the performance significantly compared to the fixed length buffering scheme that have been employed in the existing mesh-based P2P systems.

• Journal of Digital Contents Society
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• v.7 no.2
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• pp.103-108
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• 2006

Short-range wireless communication and networking technologies are becoming increasingly important in enabling useful mobile applications. for example, ZigBee technology is expected to provide low cost and low power connectivity for equipment that needs battery life as long as several months to several years. In addition, ZigBee can be implemented in mesh networks larger than is possible with Bluetooth. The main features of this ZigBee standard are network flexibility, low cost, very low power consumption, and low data rate in an adhoc self-organizing network among fixed, portable and moving devices. Home network/Home automation is one of the key market areas for Zigbee, with an example of a simple network This paper investigates the effect of short range wireless channel on the performance of Zigbee system and DSSS-BPSK signal transmission in AWGN, interference and Rician fading environments. And we investigate performance degradation due to interference and fading effects in short range wireless channel. In particular, the impacts of the fading and interference level on the bit error probability is shown in BER performance figures.

• Fashion & Textile Research Journal
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• v.15 no.2
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• pp.231-239
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• 2013

This research developed a smart girdle for adult women in their 20's that has an inserted carbon weaving heater to help with relief from coldness and abdominal disease through the thermal insulation effect. A pocket of powernet fabric was attached to the inside of the girdle for the easy insertion and separation of the heating device, while the heating device was fixed to a mesh material by cotton yarn and was wrapped with elastic lining material to prevent the mechanical devices from being exposed. A set of 3 hooks was attached to the center of the back of the heating device in consideration of convenience and mobility. Whereas the switch was inserted into around the right waistband, and the battery into the inner pocket around the waist, to integrate the heating device with the girdle. The satisfaction and usability of the fabricated smart girdle was verified by having research participants wear it to evaluate the appearance change caused by the device, the inconvenience of wearing/unwearing, mobility, and the satisfactory functionality of the device. As a result, the grand mean was evaluated to be high, with appearance (4.19), mobility (4.17), and functionality (4.51) being higher than 4.00; which indicates that the heat generation function of the smart girdle is effective. It may be said that such collection and analysis of data that reflect users' opinions have value and significance in that they can be grafted onto future research on new technology as well as they contribute to taking a step forward in the rapidly increasing research of smart clothing, with the new-type clothing equipped with new function.