• Korean Journal of Poultry Science
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• v.47 no.2
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• pp.107-114
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• 2020

This study was conducted to investigate the variation in nutrient composition of oilseed meals and to develop prediction equations for amino acid concentrations. Energy and nutrient contents were determined in a total of 1,380 feed ingredient samples including copra byproducts, corn distillers, dried grains with solubles, palm kernel byproducts, and soybean meal. The ingredient samples were imported to the Republic of Korea between 2006 and 2015. Data were analyzed using the MIXED procedure of SAS. The regression procedure of SAS was used to generate the prediction equation for the lysine concentration using the crude protein (CP) concentration as an independent variable. The concentrations of moisture, gross energy, CP, ether extract, crude fiber, ash, calcium, phosphorus, lysine, methionine, cysteine, and threonine in tested oilseed meals differed (P<0.05) depending on producing countries. The prediction equations for amino acid concentrations (% as-is basis) in the oilseed meals are: lysine = -1.08 + 0.080 × CP (root mean square error = 0.244, R² = 0.924, and P<0.001); threonine = -0.297 + 0.044 × CP (root mean square error = 0.099, R² = 0.958, and P<0.001). In conclusion, energy and nutrient compositions vary in the oilseed meals depending on the producing countries. Moreover, the crude protein concentration can be used as a suitable independent variable for estimating lysine and threonine concentrations in the oilseed meals.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.47-53
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• 1999

The effect of coating of liner components with oxidized starch on the properties of corrugated box was examined . Coating was carried out on liner components of B flute, single-wall corrugated board(SK180/S120/K200) , and corrugated box was made from the treated corrugated board. Box was made in a regular slotted container (RSC) style, and box compression strength was determined in the direction of top-to-bottom compression. The compression strength of box coated on outside liner component showed 15.4% improvement for 1.58g㎡ coating. On the other hand, the strength of box coated on outside liner component showed only 1.45% improvement for 1.41g/㎡ coating and 3.46% improvement for 2.32g/㎡ coating. Coating on inside liner component with oxidized starch at low coating weight more significantly improved box compression strength than coating on outside liner component, and the improvement was marked at the coating weight of 1.5-2.5g/㎡. In estimating top-to-bottom box compression strength, the experimental values were closer to the calculated values from McKee's equation suing edgewise compression strength of the combined board measured by column crush test than those from Kellicutt's equation using compression strength of component paperboards measured by ring crush test.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.8-13
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• 2017

The rolled carbon steel plate has anisotropic property in Z-direction(thickness direction). This is induced by cooling rate difference of Z-direction and sulfur which make non-metallic inclusion(MnS) at center line of thickness direction. Z-directional mechanical properties of normal steel plate are not generally specified and it is defined for Z-Quality steel only through tensile test in Z-direction. If Z-quality steel is not applied for cruciform joint, the lamella tearing will be occurred by tensile stress after welding & during operation of the structure. In this research, one equation estimating Z-directional(orthogonal to plate) stress was developed to prevent lamella tearing by welding. This equation deals with plate thickness & joint configuration(eccentricity, angle and curvature). Analyses were done by strain boundary method using sectional FE modeling and FE 3D models are also used for some cases. Designers can predict the possibility of lamella tearing by adequately applying the result and can appropriately minimize the application of Z-quality steel by revising welding design to some extent.

• Journal of Construction Engineering and Project Management
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• v.4 no.3
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• pp.13-20
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• 2014

Estimating time and cost is an important mission in the early phase of a construction project, especially in feasibility study. It provides a foundation for making decision whether or not the project is performed on schedule and within budget. Thus, reliability of this estimate plays a key role in measuring the success of a project. This study was carried out to investigate the time-cost relationship in building construction projects in Bangladesh. The mathematical equation used in this study is based on Bromilow's equation. The research data were collected from sixty-three completed building projects through questionnaire survey. Type of clients, type of projects, and tender methods are the project characteristics considered in this study. The results of analysis indicated that the Bromilow's time-cost (BTC) models developed for each project characteristic are appropriate due to quite high coefficient of determination and relatively small mean percent errors. Among them, the forecasted model for time and cost according to tender methods is the best fit model. It is concluded that the BTC model could be applied in building construction project to predict its time and cost in Bangladesh. Four different regression models were also developed in this study. The results of BTC model between some selected countries were compared to gain the comprehensive view.

• Journal of Mechanical Science and Technology
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• v.15 no.8
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• pp.1165-1173
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• 2001

This paper deals with dynamic analysis of Pipeline Inspection Gauge (PIG) flow control in natural gas pipelines. The dynamic behaviour of PIG depends on the pressure differential generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. To analyze dynamic behaviour characteristics (e.g. gas flow, the PIG position and velocity) mathematical models are derived. Tow types of nonlinear hyperbolic partial differential equations are developed for unsteady flow analysis of the PIG driving and expelled gas. Also, a non-homogeneous differential equation for dynamic analysis of the PIG is given. The nonlinear equations are solved by method of characteristics (MOC) with a regular rectangular grid under appropriate initial and boundary conditions. Runge-Kutta method is used for solving the steady flow equations to get the initial flow values and for solving the dynamic equation of the PIG. The upstream and downstream regions are divided into a number of elements of equal length. The sampling time and distance are chosen under Courant-Friedrich-Lewy (CFL) restriction. Simulation is performed with a pipeline segment in the Korea gas corporation (KOGAS) low pressure system. Ueijungboo-Sangye line. The simulation results show that the derived mathematical models and the proposed computational scheme are effective for estimating the position and velocity of the PIG with a given operational condition of pipeline.

• Journal of Biomedical Engineering Research
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• v.8 no.1
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• pp.41-48
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• 1987

In estimating the freguency-dependent attenuation coefficient, we analyzed the range-dependent ultrasonic beam and proposed the method of calculating the experimental equation of beam pattern in order to reduce the error on the influence of beam pattern. These experimental equations are divided into the spectral centroid and the spec ural standard deviation slope according to axial propagation length. These are repnesented by the first-order equation in the near field of the beam and the second- order eqLlatlon In the far field. In order to prove the validity of this method, the attenuation coefficients of the non-corrected ease and the corrected case are compared. Using the reflected signal from acryle plate, the attenuation coefficients were estimated by the spectral shift method ann the spectral difference method. The result shows attenuation coeffi talents after correction are better than attenuation coefficients before correction. And this method can be applied In vivo measurement.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1023-1029
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• 2005

In this paper, a dynamic model for the rotor shaft-coupling-blade system was developed. The blades are attached to a disk and driven by an electric motor shaft which is flexible in torsion. We assumed that the shaft torsional flexibility was lumped in the flexible coupling which is usually adopted in rotor systems. The Lagrangian approach with the small deformation theory for both blade-bending and shaft-torsional deformations was employed for developing the equation of the motion. The Assumed Modes Method was used for estimating the blade transverse deflection. The numerical results highlight the effects of both structural damping of the system and the torsional stiffness of the flexible coupling to the dynamic response of the blade. The results showed strong coupling between the blade bending and shaft torsional vibrations in the form of inertial nonlinearity, stiffness hardening and softening.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.150-159
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• 2014

A simplified method for the calculation of buckling and vibrational characteristics of initially stressed rectangular plate and antisymmetric angle-ply laminated plates is presented in this paper using the natural frequencies under unloading state. The equation of motion of rectangular plate with two opposite edges simply supported is investigated on the basis of Rayleigh-Ritz method and Mindlin plate theory with effect of the curvature term. The relationships of the non-dimensional natural frequencies with initial stresses the coeffcients of critical buckling and the boundaries of the dynamic principal instability region can be characterized by the non-dimensional natureal frequencies under unloading state. Numerical examples are presented to verify the simplified equations and to illustrate potential applications of the analysis.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.741-758
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• 2013

In this study, inelastic displacement ratios are investigated for existing systems with known lateral strength considering soil structure interaction. For this purpose, SDOF systems for period range of 0.1-3.0 s with different hysteretic behaviors are considered for a number of 18 earthquake motions recorded on soft soil. The effect of stiffness degradation on inelastic displacement ratios is investigated. The Modified Clough model is used to represent structures that exhibit significant stiffness degradation when subjected to reverse cyclic loading and the elastoplastic model is used to represent non-degrading structures. Soil structure interaction analyses are conducted by means of equivalent fixed base model effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. A new equation is proposed for inelastic displacement ratio of system with SSI with elastoplastic or degrading behavior as a function of structural period ($\tilde{T}$), strength reduction factor (R) and period lengthening ratio ($\tilde{T}$/T). The proposed equation for $\tilde{C}_R$ which takes the soil-structure interaction into account should be useful in estimating the inelastic deformation of existing structures with known lateral strength.

• Earthquakes and Structures
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• v.2 no.1
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• pp.89-107
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• 2011

In this paper a simple mathematical model is presented for estimating the natural frequencies and corresponding mode shapes of a tall building with outrigger-belt truss system. For this purposes an equivalent continuum system is analyzed in which a tall building structure is replaced by an idealized cantilever continuum beam representing the structural characteristics. The equivalent system is comprised of a cantilever shear beam in parallel to a cantilever flexural beam that is constrained by a rotational spring at outrigger-belt truss location. The mathematical modeling and the derivation of the equation of motion are given for the cantilevers with identically paralleled and rotational spring. The equation of motion and the associated boundary conditions are analytically obtained by using Hamilton's variational principle. After obtaining non-trivial solution of the eigensystem, the resulting is used to determine the natural frequencies and associated mode shapes of free vibration analysis. A numerical example for a 40 story tall building has been solved with proposed method and finite element method. The results of the proposed mathematical model have good adaptation with those obtained from finite element analysis. Proposed model is practically suitable for quick evaluations during the preliminary design stages.