• Steel and Composite Structures
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• v.48 no.2
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• pp.113-130
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• 2023

The present manuscript aims to investigate the deviation between the middle surface (MS) and neutral surface (NS) formulations on the static response of bi-directionally functionally graded (BDFG) porous plate. The higher order shear deformation plate theory with a four variable is exploited to define the displacement field of BDFG plate. The displacement field variables based on both NS and on MS are presented in detail. These relations tend to get and derive a new set of boundary conditions (BCs). The porosity distribution is portrayed by cosine function including three different configurations, center, bottom, and top distributions. The elastic foundation including shear and normal stiffnesses by Winkler-Pasternak model is included. The equilibrium equations based on MS and NS are derived by using Hamilton's principles and expressed by variable coefficient partial differential equations. The numerical differential quadrature method (DQM) is adopted to solve the derived partial differential equations with variable coefficient. Rigidities coefficients and stress resultants for both MS and NS formulations are derived. The mathematical formulation is proved with previous published work. Additional numerical and parametric results are developed to present the influences of modified boundary conditions, NS and MS formulations, gradation parameters, elastic foundations coefficients, porosity type and porosity coefficient on the static response of BDFG porous plate. The following model can be used in design and analysis of BDFG structure used in aerospace, vehicle, dental, bio-structure, civil and nuclear structures.

• Steel and Composite Structures
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• v.44 no.4
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• pp.451-471
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• 2022

In the present paper, the static bending and buckling responses of functionally graded carbon nanotubes-reinforced composite (FG-CNTRC) beam under various boundary conditions are investigated within the framework of higher shear deformation theory. The significant feature of the proposed theory is that it provides an accurate parabolic distribution of transverse shear stress through the thickness satisfying the traction-free boundary conditions needless of any shear correction factor. Uniform (UD) and four graded distributions of CNTs which are FG-O, FG-X, FG- and FG-V are selected here for the analysis. The effective material properties of FG-CNTRC beams are estimated according to the rule of mixture. To model the FG-CNTRC beam realistically, an efficient Hermite-Lagrangian finite element formulation is successfully developed. The accuracy and efficiency of the present model are demonstrated by comparison with published benchmark results. Moreover, comprehensive numerical results are presented and discussed in detail to investigate the effects of CNTs volume fraction, distribution patterns of CNTs, boundary conditions, and length-to-thickness ratio on the bending and buckling responses of FG-CNTRC beam. Several new referential results are also reported for the first time which will serve as a benchmark for future studies in a similar direction. It is concluded that the FG-X-CNTRC beam is the strongest beam that carries the lowest central deflection and is followed by the UD, V, Λ, and FG-O-CNTRC beam. Besides, the critical buckling load belonging to the FG-X-CNTRC beam is the highest, followed by UD and FG-O.

• Geomechanics and Engineering
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• v.31 no.1
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• pp.99-112
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• 2022

The present study examines the natural frequencies (NFs) of perfect/imperfect functionally graded sandwich beams (P/IP-FGSBs), which are composed of a porous core constructed of functionally graded materials (FGMs) and a homogenous isotropic metal and ceramic face sheets resting on elastic foundations. To accomplish this, the material properties of the FGSBs are assumed to vary continuously along the thickness direction as a function of the volume fraction of constituents expressed by the modified rule of the mixture, which includes porosity volume fraction represented using four distinct types of porosity distribution models. Additionally, to characterize the reaction of the two-parameter elastic foundation to the Perfect/Imperfect (P/IP) FGSBs, the medium is assumed to be linear, homogeneous, and isotropic, and it is described using the Winkler-Pasternak model. Furthermore, the kinematic relationship of the P/IP-FGSBs resting on the Winkler-Pasternak elastic foundations (WPEFs) is described using trigonometric shear deformation theory (TrSDT), and the equations of motion are constructed using Hamilton's principle. A closed-form solution is developed for the free vibration analysis of P/IP-FGSBs resting on the WPEFs under four distinct boundary conditions (BCs). To validate the new formulation, extensive comparisons with existing data are made. A detailed investigation is carried out for the effects of the foundation coefficients, mode numbers (MNs), porosity volume fraction, power-law index, span to depth ratio, porosity distribution patterns (PDPs), skin core skin thickness ratios (SCSTR), and BCs on the values of the NFs of the P/IP-FGSBs.

• Food Science and Preservation
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• v.30 no.5
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• pp.743-757
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• 2023

The formulation of a novel functional fresh apple juice enriched with dietary prebiotic fiber (inulin or polydextrose), ginger extract (GE), and cardamom essential oil (CEO) was carried out based on a combined D-optimal design. In the first stage, sensory evaluation was performed to screen and select the optimum sample for further experiments. The sensory evaluation showed that the sample containing inulin 0.25 g/100 g GE and 0.03 g/100 g CEO had the highest organoleptic score. In the second stage, various chemical experiments, including pH, acidity, formalin index, total phenol, flavonoids, antioxidant capacity, and vitamin C content, were evaluated on the selected enriched apple juices. The addition of GE and CEO caused changes in nutritional characteristics, including antioxidant capacity, total phenol, flavonoids, vitamin C, and IC50, from 35 g/100 g, 350 mg GAE/g, 17 mg/L, 370 mg/kg, and 1,800 mg/kg to 45 g/100 g, 460 mg GAE/g, 21 mg/L, 420 mg/kg, and 1,200 mg/kg respectively. The steady shear flow and dynamic oscillatory shear rheological tests were also performed on the screened samples, and results showed that the addition of dietary fiber in apple juices increased the apparent viscosity, storage modulus, loss modulus, and complex viscosity. In general, adding plant extracts and processed essential oil to apple juice increased the nutritional-nutraceutical value and sensory attributes of apple juice.

• The Korea Journal of Herbology
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• v.39 no.2
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• pp.19-25
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• 2024

Objectives : Jeopgoltang (JGT) is a new Korean herbal medicine formulation that is used to treat bone fractures. Although JGT is frequently used in clinical practice, there is a lack of scientific evidence on its safety. This study aimed to evaluate the preclinical toxicity of JGT using a single oral dose toxicity test in Sprague-Dawley (SD) rats. Methods : Five male and female rats per group were orally administered 1,250, 2,500, or 5,000 mg/kg of JGT after fasting for 12 h. Mortality and changes in clinical signs, body weight, and necropsy findings were monitored for 14 days according to the guidelines of the Korean Ministry of Food and Drug Safety and Organisation for Economic Co-operation and Development (OECD). Results : No significant clinical signs or mortality were observed after a single administration of up to 5,000 mg/kg. In addition, no significant necropsy findings related to JGT administration were observed. Conclusions: In conclusion, these results suggest that approximate Lethal Dose (ALD) of JGT on SD rats is over 5,000 mg/kg.

• Structural Engineering and Mechanics
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• v.90 no.3
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• pp.233-252
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• 2024

This research explores a new finite element model for the free vibration analysis of bi-directional functionally graded (BDFG) beams. The model is based on an efficient higher-order shear deformation beam theory that incorporates a trigonometric warping function for both transverse shear deformation and stress to guarantee traction-free boundary conditions without the necessity of shear correction factors. The proposed two-node beam element has three degrees of freedom per node, and the inter-element continuity is retained using both C1 and C0 continuities for kinematics variables. In addition, the mechanical properties of the (BDFG) beam vary gradually and smoothly in both the in-plane and out-of-plane beam's directions according to an exponential power-law distribution. The highly elevated performance of the developed model is shown by comparing it to conceptual frameworks and solution procedures. Detailed numerical investigations are also conducted to examine the impact of boundary conditions, the bi-directional gradient indices, and the slenderness ratio on the free vibration response of BDFG beams. The suggested finite element beam model is an excellent potential tool for the design and the mechanical behavior estimation of BDFG structures.

• Structural Engineering and Mechanics
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• v.90 no.3
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• pp.253-261
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• 2024

This research explores a new finite element model for the free vibration analysis of bi-directional functionally graded (BDFG) beams. The model is based on an efficient higher-order shear deformation beam theory that incorporates a trigonometric warping function for both transverse shear deformation and stress to guarantee traction-free boundary conditions without the necessity of shear correction factors. The proposed two-node beam element has three degrees of freedom per node, and the inter-element continuity is retained using both C1 and C0 continuities for kinematics variables. In addition, the mechanical properties of the (BDFG) beam vary gradually and smoothly in both the in-plane and out-of-plane beam's directions according to an exponential power-law distribution. The highly elevated performance of the developed model is shown by comparing it to conceptual frameworks and solution procedures. Detailed numerical investigations are also conducted to examine the impact of boundary conditions, the bi-directional gradient indices, and the slenderness ratio on the free vibration response of BDFG beams. The suggested finite element beam model is an excellent potential tool for the design and the mechanical behavior estimation of BDFG structures.

• Journal of the Korea Society of Computer and Information
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• v.29 no.8
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• pp.1-9
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• 2024

In this paper, we propose a new approach by analyzing driver behavior and gaze changes within the vehicle in real-time to assess and predict the risk of traffic accidents. Utilizing data analysis and machine learning algorithms, this research precisely measures drivers' abnormal behaviors and gaze movement patterns in real-time, and aggregates these into an overall Risk Score to evaluate the potential for traffic accidents. This research underscores the significance of internal factors, previously unexplored, providing a novel perspective in the field of traffic safety research. Such an innovative approach suggests the feasibility of developing real-time predictive models for traffic accident prevention and safety enhancement, expected to offer critical foundational data for future traffic accident prevention strategies and policy formulation.

• Applied Biological Chemistry
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• v.22 no.2
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• pp.123-134
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• 1979

For the purpose of developing a microbial insecticide utilizing Bacillus thuringiensis Berliner, research was done and the following results were obtained. 1) As the freeze-dried matter of the cocoon-cooked water discarded from the filature contains much crude protein(51.825%) and a lot of inorganic salts, it can make a good nutrition source for the culture cf B. thuringiensis Berliner. 2) Based on the suspensibility, formula F-5 turned out to be the most suitable for insecticidal use. Its composition includes 0.2 g of the cell-spore-crystal mixture, 25 g of 200-mesh kaolin, 2.5 g of New Kalgen-NX-150, and 2.5 g of glycerine admixed with 8 ml of distilled water and granulated in 80-mesh size. 3) All the components of F-5, F-6 and F-7 are identical except that the amounts of cell-spore-crystal mixture of F-5, F-6, and F-7 are 0.2 g, 0.4 g, and 0.6 g, respectively. Accordingly, their physical properties are almost all the same. 4) Formulas F-5, F-6, and F-7 exhibited an excellent toxicity to Anomis mesogona Walker, Dendrolimus spectabilis Butler, and Margaronia perspectalis Walker at the concentration of 5%. 5) Formulas F-8 and F-9 which contain $NaHCO_3$ as one of their components showed a remarkably reduced toxicity to Anomis mesogona Walker and Dendrolimus spectabilis Butler than F-6 which does not contain $NaHCO_3$. 6) A maximum of $2.97{\times}10^9$ spores per ml was obtained by incubating B. thuringiensis in M-3 which has a pH of 7.05 and comprises 0.2% of ammonium sulphate and 0.8% of glucose dissolved in the cocoon-cooked water, with aeration for 96 hours. 7) Formula F-6 exhibited a somewhat reduced toxicity to Anomis mesogona Walker and Dendrolimus spectabilis Butler, when stored at room temperature for 70 days after formulation and it is desirable to keep it in a dark and cold place. 8) In held applications, formula F-6 showed a good activity in controlling Monema flavescens Walker. Margaronia perspectalis Walker, and Macrosiphum ibarae Matsumura.

• Journal of Intelligence and Information Systems
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• v.16 no.2
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• pp.129-141
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• 2010

An Internet shopping mall for clothing operates a warehouse for packing and shipping products to fulfill its orders. All the products in the warehouse are put into the boxes of same brands and the boxes are stored in a row on shelves equiped in the warehouse. To make picking and managing easy, boxes of the same brands are located side by side on the shelves. When new products arrive to the warehouse for storage, the products of a brand are put into boxes and those boxes are located adjacent to the boxes of the same brand. If there is not enough space for the new coming boxes, however, some boxes of other brands should be moved away and then the new coming boxes are located adjacent in the resultant vacant spaces. We want to minimize the movement of the existing boxes of other brands to another places on the shelves during the warehousing of new coming boxes, while all the boxes of the same brand are kept side by side on the shelves. Firstly, we define the adjacency of boxes by looking the shelves as an one dimensional series of spaces to store boxes, i.e. cells, tagging the series of cells by a series of numbers starting from one, and considering any two boxes stored in the cells to be adjacent to each other if their cell numbers are continuous from one number to the other number. After that, we tried to formulate the problem into an integer programming model to obtain an optimal solution. An integer programming formulation and Branch-and-Bound technique for this problem may not be tractable because it would take too long time to solve the problem considering the number of the cells or boxes in the warehouse and the computing power of the Internet shopping mall. As an alternative approach, we designed a fast heuristic method for this reallocation problem by focusing on just the unused spaces-empty cells-on the shelves, which results in an assignment problem model. In this approach, the new coming boxes are assigned to each empty cells and then those boxes are reorganized so that the boxes of a brand are adjacent to each other. The objective of this new approach is to minimize the movement of the boxes during the reorganization process while keeping the boxes of a brand adjacent to each other. The approach, however, does not ensure the optimality of the solution in terms of the original problem, that is, the problem to minimize the movement of existing boxes while keeping boxes of the same brands adjacent to each other. Even though this heuristic method may produce a suboptimal solution, we could obtain a satisfactory solution within a satisfactory time, which are acceptable by real world experts. In order to justify the quality of the solution by the heuristic approach, we generate 100 problems randomly, in which the number of cells spans from 2,000 to 4,000, solve the problems by both of our heuristic approach and the original integer programming approach using a commercial optimization software package, and then compare the heuristic solutions with their corresponding optimal solutions in terms of solution time and the number of movement of boxes. We also implement our heuristic approach into a storage location assignment system for the Internet shopping mall.