• Journal of applied mathematics & informatics
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• v.31 no.1_2
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• pp.131-145
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• 2013

In this paper, we present an initial value technique for solving singularly perturbed differential difference equations with a boundary layer at one end point. Taylor's series is used to tackle the terms containing shift provided the shift is of small order of singular perturbation parameter and obtained a singularly perturbed boundary value problem. This singularly perturbed boundary value problem is replaced by a pair of initial value problems. Classical fourth order Runge-Kutta method is used to solve these initial value problems. The effect of small shift on the boundary layer solution in both the cases, i.e., the boundary layer on the left side as well as the right side is discussed by considering numerical experiments. Several numerical examples are solved to demonstate the applicability of the method.

• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.194-198
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• 2001

Contaminated sites are often abandoned for an extended period of time, thus organopollutants becoming sequestered. The information on the initial concentrations of the contaminants would be helpful for the economic bioremediation of the chemicals. The present study estimated the initial concentrations of atrazine and phenanthrene through multiple regression analyses using soil properties and the amount of chemicals available in situ. Percentage mineralized or extracted was best correlated with organic C or logarithm of organic C, and the $R^2$ values were 0.548 and 0.894 for atrazine and phenanthrene, respectively. Estimation of the initial concentration of the chemicals was then calculated from both the percentage mineralized or extracted and the amount of chemicals extracted or mineralized. Results showed that the estimation of the initial concentration of the chemical at the time of contamination is feasible.

• Transactions of Materials Processing
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• v.7 no.5
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• pp.459-464
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• 1998

Effect of the several initial textures such as random texture, rolling texture and cube texture, on the plane strain stretching was studied by interpretation of the finite element method. The calculation of yield locus indicated that the sheet oriented in the cube texture exhibits easy yielding on uniaxial stress state whereas the sheet having either a random or the rolling texture exhibits easy yielding on shear deformation. Upon stretching tests, the thickness strain at the center region contacting the punch was identical regardless of the initial textures while the dependence of the thickness strain on the initial texture was found in the other regions. In general punch loads required or the sheet with an initial cube texture was as expected from calculated yield locus, lower than those for the others.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.32-36
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• 2006

The initial hull form of a 100 tan, 45 knot class high-speed craft is newly developed. The resistance performances are investigated using a model test at high speed in a circulating water channel. The effect of the initial trim is studied together. Wave patterns are observed to clarify the relationship between the resistance performance and the wave characteristics. It can be found that the initial trim plays a role in increasing the resistance performance above a certain velocity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.67-70
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• 2005

The carbon fiber reinforced/epoxy laminated composites were fabricated with initial fiber failures within the unidirectional fiber pre-pregnated ply. The fiber failures were made intentionally either parallel to and/or perpendicular to the unidirectional fibers within the ply. The pre-made clear-cut cracks were found to be healed partially after laminating process. The laminates were impacted with or without initial fiber failures within the laminates. The force versus deflection curves were compared. The partially healed laminates showed the reduced laminate stiffness as compared to those without any intentional fiber failures. The impact curves were compared with size and the location of the initial failures varied.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.527-534
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• 1997

Freezing of an aqueous sodium cWoride solution (Nacl- H20) saturating a packed bed with ini¬tial salt concentrations of 5, 10, 15(k by weight is investigated experimentally in a rectangular cav¬ity. The system was cooled from the top, bottom and a vertical side wall. For the freezing experi¬ments from below, there was little effect of the initial salt concentration throughout the freezing process, and the global freezing rate was not affected by the initial salt concentration. For the freezing from above, the size of the mush region decreased and the mushlliquid interface became flatter as the initial liquid concentration is decreased. For the freezing from vertical side wall, reheating of the mixture was intensified with an increase in the initial salt concentration. For Ci= 5%, supercooling was observed only at the early times of freezing process, but for Ci= 15% small supercooling was observed throughout the freezing process.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.8
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• pp.1132-1140
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• 1998

The disintegration process of initial spray from high-pressure swirl injector was investigated at different injection pressures. The transient breakup phenomena that were difficult to observe at high injection pressure were easily observed at the low injection pressure of 0.4MPa. The effect of fuel remained inside a nozzle hole volume on the penetration of initial spray was also investigated. The disintegration process of initial spray could be classified four regions: the formation of mushroom shape, the first collision, the second collision, and the development of spray, The liquid film of cup shape was particularly found in the second collision region, and the growth ratio of its length and width at low and high injection pressures were compared.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1594-1603
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• 2002

In this paper, when the initial propagation angle of a branched crack is calculated from the maximum tangential stress criterion (MTSC) and the minimum strain energy density criterion (MSEDC), it is essential that you use stress components in which higher order terms are considered and stress components at the position in a distance 0.005㎜ from the crack tip (=r). When an interfacial crack propagates along the interface at a constant velocity, the initial propagation angles of the branched crack are similar. to the mode mixities (phase angle) and the theoretical values obtained from MTSC and MSEDC. The initial propagation angle of the branched crack depends considerably on the stress intensity factor K$_2$.

• MALSORI
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• no.38
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• pp.125-136
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• 1999

This study examined the perception and production of Korean lax, fortis and aspirated stops in three apraxic patients. All of tile subjects made more production errors than perception errors. This indicates that apraxic patients have problems in phonetic execution rather than phonological representation. Additionally, in both production and perception, there were more errors in non-word-initial consonants than in word-initial consonants. These findings contradict those of the previous studies which report more errors in word-initial consonants. This study also found that, unlike previous studies in the types of errors made, distortion errors were high in both non-word-initial and word-initial consonants in apraxic patients. Generally, VOT of the stops showed significant differences among lax, fortis, and aspirated stops, which indicates that there is a failure not in choosing the appropriate stop but in positioning or motor planning at the articulation stage.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.22-29
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• 1997

This paper presents results on dynamic analysis of the missile initial motion arising from the missile detent force. Using ADAMS (Automatic Dynamic Analysis of Mechanical Syatem) software, a non- linear46-DOF (Degree of Freedom) model is developed for the launcher system including missile and lunch tube contact problem. From the dynamic analysis, it is found that initial angular velocity of the missile incre- ases when the missile detent force increases and also when rocket exhaust plume is taken into account. To achieve the missile launching stability, it needs to reduce the missile initial detent force and exhaust plume area of the lancher. Results of the dynamic analysis on the system natural frequency agree well with those obtained from experimental modal tests. The overall results suggest that the proposed method is a useful tool for prediction of initial missile stability as well as design of the missile launcher system.