• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.9
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• pp.2953-2964
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• 1996

Heat Transfer with periodic fluctuation of fluid temperature caused by oscillatory flow or compression expansion can be out of phase with balk fluid-wall temperature difference. Newton's law of convection is inadequate to describe this phenomenon. In order to solve this problem the concept of the complex Nusselt number has been introduced by severla researchers. The complex Nusselt number expresses out of phase excellently while the first harmonic is dominant in the variations of both fluid-wall temperature difference and heat flux. However, in the case of oscillatory flow with non-linear wall temperature distribution, the complex Nusselt number is not appropriate to predict the heat transfer phenomena since the higher order harmonic components appear in periodic temperature variation. Analytic solutions to the heat transfer with an sinusoidal well temperature distribution were obtained to investagate the effect of non-linear wall temperature distribution. A new formula considering the thermal boundary layer was suggested based on the solutions. A comparison was also made with the complex Nusselt number. It was verified that the new formula describes well the heat transfer of oscillating flow even if the first harmonic component is not dominant in the fluid-wall temperature difference.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4724-4737
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• 2018

Facebook has quickly infused across cultures worldwide to become a common household term for diverse spectra of netizens, especially youngsters. Inherently, interactive in nature, Facebook provides a common cyber enabled platform for online interactions with social friends, living across the world. However, despite its merits, users also experience certain disadvantages, which include but are not limited to rise in feelings of social comparison, decline in self-esteem, contentment and general subjective well-being. This work aims to determine the role of Facebook in spreading envy and identify factors that trigger such emotions. Due to abductive nature of the study, we used pilot interviews and consulted relevant literature to formulate hypotheses. Further, we used deductive approach and conducted a survey. The results showed that frequent use of Facebook, particularly passive following is main predictor of envy, and social interaction is the biggest cause for development of envious feelings in Facebook users. However, insignificant variation was found while investigating relationship between envy and factors, such as pretentiousness, time spent, accomplishment, everything in life, likes on posts, popularity across genders, marital status and genre.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.2
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• pp.120-128
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• 2013

This paper presents the results of sloshing experiments having different fluids in model tanks with various density ratios. The experimental model consisting water and air at ambient, which has been commonly used, is not consistent in density ratio with that of an actual LNG cargo tank. Therefore, an advanced experimental scheme is developed to consider the same density ratio of LNG and NG by using a mixed gas of sulfur hexafluoride ($SF_6$) and nitrogen ($N_2$). For experimental observation, a two-dimensional model tank of 1/40 scale and a three-dimensional model tank of 1/50 scale have been manufactured and tested at various conditions. Two different fillings with various excitation frequencies under regular motions have been considered for the two-dimensional model tank, and three different filling levels under irregular motions have been imposed for the three-dimensional model tank. The density ratio between gas and liquid varies from the ratio of the ambient air and water to that of the actual LNG cargo container, and the different composition of gas is used for this variation. Based on the present experimental results, it is found that the decrease of sloshing pressure is predicted when the density ratio increases.

• Tunnel and Underground Space
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• v.8 no.3
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• pp.234-248
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• 1998

This paper presents a new constitutive model for numerical modeling the shear behaviour of rough rock joints. The model incorporates the dilatancy of joints on the basis of elasto-plastic theory. Barton's empirical shear strength formular are adopted in the formulation process. The mobilized JRC concept is evoked to address the shear strength hardening and sofrening phenomena. The mobilized JRC in the pre- and post-peak range is approximated by assuming that the variation of JRC is a function of tangential plastic work. Discrete finite joint element is used to implement the proposed constitutive model. The model is validated by the numerical direct shear test on a single joint which is subjected to different boundary conditions. The test results are in good agreement with the experimental observations reported by other authors. The numerical tests also exhibit that the proposed model can simulate the salient features envisaged in the behaviour of rough rock joints.

• Journal of Arbitration Studies
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• v.24 no.2
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• pp.161-181
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• 2014

This thesis, which mainly focuses on the characteristics of the Chinese arbitration system, will mainly deal with three characteristics and analyze the causes that directly or indirectly influence them. The first characteristic is China does not recognize ad hoc arbitration. Ad hoc arbitration is the initial form of arbitration, and it occupies an important position in many countries; however, China's judicial system does not recognize it. There are many disadvantages for building a system of ad hoc arbitration in China; i. e., the arbitration system in China is undeveloped and shot-time established, and it lacks social and civil society basis, along with a credit system, which the Western ad hoc arbitration relies on. The second characteristic is the existence of excessive judicial supervision and control over arbitration in China. Judicial supervision over arbitration has been the customary practice in each country of the modern world, but sharp variation exists in the legal stipulations and the courts' attitude toward the standard to be applied in the supervision over arbitration. In China, there has always been a controversy over judicial supervision, and the standards applied in the supervision over arbitration by courts in different regions are less than identical. The last characteristic is the existence of a combination of mediation with arbitration, which is called Arb-Med in China. Such means that in the process of arbitration, the arbitrator may conduct mediation proceedings for the case it is handling if both parties agree to do so. Under the Chinese law, Arb-Med may lead to a binding and enforceable outcome. However, it has several legal disadvantages and almost no country adopts this system. China still insists that this system will go on because Arb-Med was first made in China, and its effect was proven through long-time practice in CIETAC.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6059-6064
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• 2014

Background: Colorectal cancer is the second most frequent cancer in Malaysia. Nevertheless, there is little information on treatment and outcomes nationally. We aimed to determine the demographic, clinical and treatment characteristics of colorectal cancer patients treated at the University Malaya Medical Centre (UMMC) as part of a larger project on survival and quality of life outcomes. Materials and Methods: Medical records of 1,212 patients undergoing treatment in UMMC between January 2001 and December 2010 were reviewed. A retrospective-prospective cohort study design was used. Research tools included the National Cancer Patient Registration form. Statistical analysis included means, standard deviations (SD), proportions, chi square, t-test/ANOVA. P-value significance was set at 0.05. Results: The male: female ratio was 1.2:1. The mean age was 62.1 (SD12.4) years. Patients were predominantly Chinese (67%), then Malays (18%), Indians (13%) and others (2%). Malays were younger than Chinese and Indians (mean age 57 versus 62 versus 62 years, p<0.001). More females (56%) had colon cancers compared to males (44%) (p=0.022). Malays (57%) had more rectal cancer compared to Chinese (45%) and Indians (49%) (p=0.004). Dukes' stage data weres available in 67%, with Dukes' C and D accounting for 64%. Stage was not affected by age, gender, ethnicity or tumor site. Treatment modalities included surgery alone (40%), surgery and chemo/radiotherapy 32%, chemo and radiotherapy (8%) and others (20%). Conclusions: Significant ethnic differences in age and site distribution, if verified in population-based settings, would support implementation of preventive measures targeting those with the greatest need, at the right age.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.1
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• pp.21-28
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• 2008

Stress-strain curves based on Ramberg-Osgood and Hollomon relations are strongly dependent upon the regressed range of strain. This work investigates mathematical expressions of true stress-strain curves of metallic materials. We first observe the variation of yield strength, strain hardening exponent and stress-strain curve with regressed range of stain. Based on sectional regression and expression using one or two parameters, we propose an optimal strain range for which yield strength and nonlinear material behavior are quite appropriate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.237-244
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• 2012

This paper studies the design of a two-DOF optimal controller for the strip gauge-tension of cold tandem mill processes, that uses a reference shaping filter and a disturbance observer. First, a mathematical model of the strip gauge and tension system is constructed using the gauge meter equation and Hooke's law, respectively. Next, a two-DOF controller considering of a feedforward controller and a feedback controller is designed. The former is based on the reference shaping filter and the disturbance observer, and the latter is based on the ILQ optimal control algorithm. Finally, it is shown through a computer simulation that the proposed optimal controller is able to improve the strip gauge accuracy and the tension variation more than the conventional MV-AGC controller.

• Earthquakes and Structures
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• v.15 no.4
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• pp.369-382
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• 2018

A free vibration analysis and wave propagation of functionally graded porous beams has been presented in this work using a high order hyperbolic shear deformation theory. Unlike other conventional shear deformation theories, a new displacement field that introduces indeterminate integral variables has been used to minimize the number of unknowns. The constituent materials of the beam are assumed gradually variable along the direction of height according to a simple power law distribution in terms of the volume fractions of the constituents. The variation of the pores in the direction of the thickness influences the mechanical properties. It is therefore necessary to predict the effect of porosity on vibratory behavior and wave velocity of FG beams in this study. A new function of the porosity factor has been developed. Hamilton's principle is used for the development of wave propagation equations in the functionally graded beam. The analytical dispersion relationship of the FG beam is obtained by solving an eigenvalue problem. Illustrative numerical examples are given to show the effects of volume fraction distributions, beam height, wave number, and porosity on free vibration and wave propagation in a functionally graded beam.

• Wind and Structures
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• v.29 no.6
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• pp.457-469
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• 2019

In this paper, a numerical solution is presented for supersonic flutter analysis of cantilever non-symmetric functionally graded (FG) sandwich plates. The plate is considered to be composed of two different functionally graded face sheets and an isotropic homogeneous core made of ceramic. Based on the first order shear deformation theory (FSDT) and linear piston theory, the set of governing equations and boundary conditions are derived. Dimensionless form of the governing equations and boundary conditions are derived and solved numerically using generalized differential quadrature method (GDQM) and critical velocity and flutter frequencies are calculated. For various values of the yaw angle, effect of different parameters like aspect ratio, thickness of the plate, power law indices and thickness of the core on the flutter boundaries are investigated. Numerical examples show that wings and tail fins with larger length and shorter width are more stable in supersonic flights. It is concluded for FG sandwich plates made of Al-Al₂O₃ that increase in volume fraction of ceramic (Al₂O₃) increases aeroelastic stability of the plate. Presented study confirms that improvement of aeroelastic behavior and weight of wings and tail fins of aircrafts are not consistent items. It is shown that value of the critical yaw angle depends on aspect ratio of the plate and other parameters including thickness and variation of properties have no considerable effect on it. Results of this paper can be used in design and analysis of wing and tail fin of supersonic airplanes.