• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.661-664
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• 1998

In this paper, the properties of inter-lacking block by the kind of aggregate and fineness modulus are investigated. According to the experimental results, compressive strength and flexural strength increase and absorption ratio decrease with larger fineness modulus in the range of 2.15~4.20. Flexural strength with river sand is higher than that with crushed sand by about 19%, compressive strength with river sand, that with crushed sand by about 11% and absorption ratio with river sand is smaller than that with crushed sand by abort 2%.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.1
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• pp.26-33
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• 1994

A tobacco ripeness grading meter was designed and constructed using the color sensor, its performance was evaluated. A degree of ripeness grading of a leaf is very closely related to the measured tobacco leaf color. Measuring the small amount of the reflectance precisely depends on the apparatus including color sensor, light source, detector sensitivity, and geometric characteristics of appratus. To analyze and minimize the variational effects, experiments to select the proper condition were performed. Because of the combined effect mentioned above, the system has some variation on its response. Basis on the results of the experiments, prototype was developed and interfaced to a computer system. The main components of prototype included a tungsten lamp as a light source, Amorphous full color sensor with three filters, regulated D.C. power supply, OP - AMP(741 TC) for amplification, AR - B3001 board for interfacing to a computer with analog to digital conversion, and a compatible IBM PC XT computer. The experimental results of the developed ripeness tobacco leaf measurement system are summarized as following: [1] The output readings of ripeness grade meter for tobacco leaf, which is based on harvesting time, showed the apparent difference in variety of different quality. It was considered suitable that three filters(red, green, blue) in Amorphous full color sensor could be used in four different ripeness degree measurement of tobacco leaf. [2] The output readings of ripeness grade meter for tobacco leaf, which is based on government procurement, showed apparent difference in variety of different quality. Tobacco leaf varieties to stalk position are divided into tips, leaf, cutters, and primings, It is considered suitable that only red filter in the sensor could be used to classify the grade of tobacco leaf within the same kind tobacco stalk. However, the ripeness grade meter was not adequate to classify all the tobacco grades in the four different tobacco leaves.

• Food Science of Animal Resources
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• v.41 no.2
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• pp.224-236
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• 2021

The objective of this study was to investigate the effects of quality grade (QG) on the physicochemical composition and eating quality attributes of pork belly and shoulder butt. Seventy-two growing-finishing crossbred pigs were slaughtered and their carcasses were graded according to the Korean pork carcass grading system. Based on the grading criteria, the carcasses were classified into: QG 1+ (n=23), QG 1 (n=23) and QG 2 (n=26) groups. At 24 h postmortem, belly and shoulder butt cuts were collected from the QG groups and used for analysis of meat quality, flavor compounds and eating quality attributes. Results showed that the variation in fat content among QG was approximately 2% in the both cut types. The QG showed no effects on all the quality traits: cooking loss, pH and color of the belly or shoulder butt (p>0.05). Thirty-five flavor compounds comprising mainly fatty acids oxidation/degradation-derived products (e.g., aldehydes) and only few Maillard reaction-derived products (e.g., sulfur-and nitrogen-containing compounds) were identified. However, the QG showed a minor effect on the flavor profiles in both the belly and shoulder butt. Regarding the sensory quality, no effects of the QG were found on all the eating quality attributes (color, flavor, juiciness, tenderness and acceptability) for both the belly and shoulder butt cuts (p>0.05). Thus, it may be concluded that the current pork carcass grading standards do not reflect the real quality and value of the belly and shoulder butt cuts.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.352-355
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• 2004

Crushed sand is made by crushing the rocks artificially. With a wide shortage of natural river sand all over the region in Korea, demand for crushed sand are becoming increased. However, Informations as to crushed sand are insufficient. In this paper, the actual conditions of crushed sand related to producing and quality variation are investigated. 29 manufacturing company of crushed sand are reviewed. According to results, density of most crushed sand tested exceeded 2.5g/cm3, and absorption ratio meet the requirement of KS except one sample. For grain properties, passing amount of 0.08mm sieve satisfied the requirement of KS except one sample. Grain distribution of most crushed sand is estimated $54.26\%$. But 6 crushed sand sample did not meet the requirement of KS. Fineness modulus and grading are varied from manufacturing region. 18 samples of crushed sand among 29 samples deviated the minimum level of standard grading range by KS. Therefore, improvement of grain properties of crushed sand is urgently needed to manufacture better crushed sand.

• Steel and Composite Structures
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• v.29 no.5
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• pp.569-578
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• 2018

This paper aims to investigate the transient vibration behavior of functionally graded carbon nanotube (FG-CNT) reinforced nanocomposite plate resting on Pasternak foundation under pulse excitation. The plate is considered to be composed of matrix material and multi-walled carbon nanotubes (MWCNTs) with distribution as per the functional grading concept. The functionally graded distribution patterns in nanocomposite plate are explained more appropriately with the layer-wise variation of carbon nanotubes weight fraction in the thickness coordinate. The layers are stacked up in such a way that it yields uniform and three other types of distribution patterns. The effective material properties of each layer in nanocomposite plate are obtained by modified Halpin-Tsai model and rule of mixtures. The governing equations of an illustrative case of simply-supported nanocomposite plate resting on the Pasternak foundation are derived from third order shear deformation theory and Navier's solution technique. A converge transient response of nanocompiste plate under uniformly distributed load with triangular pulse is obtained by varying number of layer in thickness direction. The validity and accuracy of the present model is also checked by comparing the results with those available in literature for isotropic case. Then, numerical examples are presented to highlight the effects of distribution patterns, foundation stiffness, carbon nanotube parameters and plate aspect ratio on the central deflection response. The results are extended with the consideration of proportional damping in the system and found that nanocomposite plate with distribution III have minimum settling time as compared to the other distributions.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1253-1253
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• 2001

The ability to accurately assess wine quality is important during the wine making process, particularly when allocating batches of wines to styles determined by consumer requirements. Grape payments are often determined by the quality category of the wine that is produced from them. Wine quality, in terms of sensory characteristics, is normally a subjective measure, performed by experienced winemakers, wine competition judges or winetasting panellists. By nature, such assessments can be biased by individual preferences and may be subject to day-to-day variation. Taste and aroma compounds are often present in concentrations below the detection limit of near infrared (NIR) spectroscopy but the more abundant organic compounds offer potential for objective quality grading by this technique. Samples were drawn from one of Australia's major wine shows and from BRL Hardy's post-vintage wine quality allocation tastings. The samples were scanned in transmission mode with a FOSS NIR Systems 6500, over the wavelength range 400-2500 ㎚. Data analysis was performed with the Vision chemometrics package. With samples from the allocation tastings, the best correlations between NIR spectra and tasting data were obtained with dry red wines. These calibrations used loadings in the wavelengths related to anthocyanins, ethanol and possibly tannins. Anthocyanins are a group of compounds responsible for colour in red wines - restricting the wavelengths to those relating to anthocyanins produced calibrations of similar accuracy to those using the full wavelength range. This was particularly marked with Merlot, a variety that tends to have relatively lower anthocyanin levels than Cabernet Sauvignon and Shiraz. For dry white wines, calibrations appeared to be more dependent on ethanol characteristics of the spectrum, implying that quality correlated with fruit maturity. The correlations between NIR spectra and sensory data obtained using the wine show samples were less significant in general. This may be related to the fact that within most classes in the show, the samples may span vintages, glowing areas and winemaking styles, even though they may be made from only one grape variety. For dry red wines, the best calibrations were obtained with a class of Pinot Noir - a variety that tends to be produced in limited areas in Australia and would represent the least matrix variation. Good correlations were obtained with a tawny port class - these wines are sweet, fortified wines, that are aged for long periods in wooden barrels. During the ageing process Maillard browning compounds are formed and the water is lost through the barrels in preference to ethanol, producing “concentrated” darkly coloured wines with high alcohol content. These calibrations indicated heaviest loadings in the water regions of the spectrum, suggesting that “concentration” of the wines was important, whilst the visible and alcohol regions of the spectrum also featured as important factors. NIR calibrations based on sensory scores will always be difficult to obtain due to variation between individual winetasters. Nevertheless, these results warrant further investigation and may provide valuable Insight into the main parameters affecting wine quality.

• Structural Engineering and Mechanics
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• v.37 no.5
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• pp.529-542
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• 2011

Three dimensional solutions for free vibrations analysis of functionally graded fiber reinforced cylindrical panel are presented, using differential quadrature method (DQM). The orthotropic panel is simply supported at the edges and is assumed to have an arbitrary variation of reinforcement volume fraction in the radial direction. Suitable displacement functions that identically satisfy the simply supported boundary condition are used to reduce the equilibrium equations to a set of coupled ordinary differential equations with variable coefficients, which can be solved by differential quadrature method to obtain natural frequencies. The main contribution of this work is presenting useful results for continuous grading of fiber reinforcement in the thickness direction of a cylindrical panel and comparison with similar discrete laminate composite ones. Results indicate that significant improvement is found in natural frequency of a functionally graded fiber reinforced composite panel due to the reduction in spatial mismatch of material properties.

• Smart Structures and Systems
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• v.26 no.1
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• pp.77-87
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• 2020

By employing a quasi-3D plate formulation, the present research studies static stability of magneto-electro-thermo-elastic functional grading (METE-FG) nano-sized plates. Accordingly, influences of shear deformations as well as thickness stretching have been incorporated. The gradation of piezo-magnetic and elastic properties of the nano-sized plate have been described based on power-law functions. The size-dependent formulation for the nano-sized plate is provided in the context of nonlocal elasticity theory. The governing equations are established with the usage of Hamilton's rule and then analytically solved for diverse magnetic-electric intensities. Obtained findings demonstrate that buckling behavior of considered nanoplate relies on the variation of material exponent, electro-magnetic field, nonlocal coefficient and boundary conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.43-44
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• 2017

In this study, mortar strength was measured by grinding oyster shell and changing the particle size distribution. For the experiment, the oyster shells were processed to a fine aggregate size of 10mm or less. In this experiment, seven particle size distribution conditions were selected and tested. Because oyster shells are different in density from sand, their volume ratios were calculated and converted to mass ratios of 1: 3. The strength test was carried out one day after the steam curing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.6-12
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• 2007

In this paper, an robust adaptive backstepping controller is proposed for the speed control of separately excited DC motor in pure electric vehicles. A general electric drive train of PEV is conceptually rearrange to major subsystems as electric propulsion, energy source, and auxiliary subsystem and the load torque is modeled by considering the aerodynamic, rolling resistance and grading resistance. Armature and field resistance, damping coefficient and load torque are considered as uncertainties and noise generated at applying load torque to motor is also considered. It shows that the backstepping algorithm can be used to solve the problems of nonlinear system very well and robust controller can be designed without the variation of adaptive law. Simulation results are provided to demonstrate the effectiveness of the proposed controller.