• Computers and Concrete
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• v.26 no.6
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• pp.505-513
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• 2020

Grading of aggregate influences significantly almost all of the concrete performances. The purpose of this paper is to propose practicable equations that express the optimized total aggregate gradation, by weight or by number of particles in a concrete mix. The principle is based on the fractal feature of the grading of combined aggregate in a solid skeleton of concrete. Therefore, equations are derived based on the so-called fractal dimension of the grain size distribution of aggregates. Obtained model was then applied in such a way a correlation between some properties of the dry concrete mix and the fractal dimension of the aggregate gradation has been built. This demonstrates that the parameter fractal dimension is an efficacious tool to establish a unified model to study the solid phase of concrete in order to design aggregate gradation to meet certain requirements or even to predict some characteristics of the dry concrete mixture.

• Advances in concrete construction
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• v.15 no.2
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• pp.97-114
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• 2023

The nonlocal strain gradient theory for the static bending analysis of graphene nanoplatelets (GPLs) reinforced the nanoplate is developed in this paper. The nanoplatelet is exposed to thermo-mechanical loads and is also supposed to stand on an elastic foundation. For computing impressive composite material characteristics, the Halpin-Tsai model is selected for various sectors. The various distributions are propounded including UD, FG-O, and FG-X. The represented equations are acquired based on the virtual work and sinusoidal shear and normal deformation theory (SSNDT). Navier's solution as the analytical method is applied to solve these equations. Furthermore, the effects of GPL weight fraction, temperature parameters, distribution pattern and parameters of the foundation are presented and discussed.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.169-174
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• 2013

An experimental study has been conducted for the design of the regenerative oxy-fuel combustion system with ceramic ball. Various design parameters are considered such as ball size, regenerator weight, and combustion load. Regenerative system with a pair of oxygen burners and regenerators is set up and the temperature of oxygen and exhaust gas passing through ball regenerator is measured. It is shown that the temperature distributions with time are affected by ball diameter and regenerator weight, and the significant temperature change is observed by combustion load. As the ball size decreases and the regenerator weight increases, the regenerating temperature efficiency increases. It is found that the heat recovery ratio is low despites of high regeneration temperature efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.1059-1066
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• 2008

Characteristics of pyrolysis and liquid product distribution of ABS plastics have been studied in the thermogravimetric(TG) reactor and bomb microreactor. Pyrolysis reactions were performed at temperature $400\sim450^{\circ}C$ and yield of each pyrolytic product was obtained by the weight measurement method. The molecular weight distributions of liquid products were determined by the GC-SIMDIS method. It was observed that solid residue which could not be detected in the thermogravimetric experiments was significantly formed in the batch-type microreactor. It was found that the yield and average molecular weight of liquid products were decreased with the increase of reaction temperature and time. but the formation of styrene monomer was significantly increased. The chain-end scission rate parameters were determined to be 54.1kcal/mole far ABS by the Arrhenius plot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4713-4718
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• 2013

Nowadays, three-dimensional computer added design(3D CAD) tool are widely and actively used for design of mechanical machine. Because using the tool is more effective to understand design concept and to collaborate with other operation than using two-dimensional design tool. In this study, the 3D CAD tool which is called I-DEAS was applied for three-dimensional modeling of main parts and assembling of modeled parts for identification the entire shape of a injection molding machine. In addition, a study was also performed regarding reduction for the weight of main plates for saving production cost and energy in the machine. A finite element method(FEM) program in I-DEAS tool was used for the improvement study. First, the current main plates were structural analysed and then the plate deformations, weak regions and stress distributions were graped. By the FEM results, the 2nd improved designing of the plates was conducted such as reinforcement or slimming of the plate wall thickness. The 2nd structural FEM was performed for verification of the redesigned plates and then the FEM results were compared with the 1st FEM's result. The weight of the main plates were averagely reduced approximately 3 - 7%. By these results, it was seemed that the improved plates have a useful availability.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.203-203
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• 1999

Mass spectrometry technique provides the molecular weight distribution, data on the sequence of repeat units, polymer additives, and impurities, and structural information. time-of-Flight secondary Ion Mass Spectrometry (TOF-SIMS) has been used for structural characterization of various polymers1-2. the masses of repeat units and terminal groups and molecular weight distributions of polymers have been determined from their TOF-SIMS spectra. TOF-SMIS provides good sensitivity and structural specificity for high mass ions so that intact oligomers and large polymer fragments are observed. In this study, we investigated the detailed structural information on the oligomers and fragment ions of branched poly(1,3-butylene adipate) and branched poly[di(ethylene glycol) adipate] and the transesterification products of branched polyesters with trifluoroacetic acid or chloro difluoroacetic acid. Branched polyesters were chosen because they are important polymers but difficult to characterize; thus branched polyesters provide challanging test for TOF-SIMS. TOF-SIMS spectra of polyesters are obtained from thin polymer films cast from solution on a silver substrate. A good solvent for a polumer solution disrupts intermolecular forces between polymer chains but leaves the polumer intact. Transesterification reactions are potentially useful for characterization of high molecular weight and intractable polyesters. Transesterification products of polyesters and trifluoroacetic acid or an integral number of polyester repeat units and an additional diol. The progress of such reactions was monitored using peak intensities of reactants and products in TOF-SIMS spectra. The increasing abundance of tagged ions indicates that the reaction has progressed with time.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.432-437
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• 1999

Pyrolysis of polyethylene was carried out in the stainless steel reactor of internal volume of $10cm^3$. Pyrolysis reactions were performed at temperature $390{\sim}450^{\circ}C$ and the pyrolysis products were collected separately as reaction products and gas products. The molecular weight distributions(MWDs) of each product were determined by HPLC-GPC and GC analysis. Distribution balance equation for MWDs of random and specific products were proposed to account for initiation-termination and propagation-depropagation, such as hydrogen abstraction, chain cleavage, coupling of polymer and radical. A separate chain-end scission process produces low molecular weight noncondensable gases(C1 through C5) of average molecular weight 38. Activation energies of the random-chain scission and chain-end scission rate parameters, respectively, were determined to be 35, 17 kcal/mole.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.5
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• pp.288-294
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• 2019

Gardenia jasminoides is an herbal medicine that treats obesity and dampness-phlegm. This study aimed to investigate the efficacy of Gardenia jasminoides on insulin resistance induced by Non-alcoholic fatty liver disease (NAFLD). 8-week-old C57BL/6 male mice were divided into three groups: control group (Ctrl), high-fat diet group (HFF), and high fat diet with Gardenia jasminoides extract administration group (GJT). Each 10 mice was allocated to each group (a total of 30 mice). All mice were allowed to eat fat-rich diet freely throughout the experiment. To examine the effect of Gardenia jasminoides, we observed weight changes, lipid blot distributions, PPAR-${\gamma}$, p-IkB, p-JNK in liver tissue, total cholesterol, and glucose levels in serum. Comparing of body weight measurements between 3 groups, in the GJT group, weight gain was significantly suppressed compared to the HFF group. The distribution of lipid blots and positive reaction of PPAR-${\gamma}$ were significantly lower in GJT group. The expression levels of p-$I{\kappa}B$ and p-JNK that plays critical roles in the development of insulin resistance were significantly decreased by GJ treatment. Total cholesterol and glucose levels in serum were also significantly lower in GJT group. Gardenia jasminoides has the effect of improving non - alcoholic fatty liver induced insulin resistance through the regulation of lipid metabolism.

• The Journal of Pediatrics of Korean Medicine
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• v.32 no.4
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• pp.1-12
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• 2018

Objectives Bangpungtongsungsan is an herbal medicine that treats obesity and dampness-phlegm. The aim of this study was to investigate the efficacy of Bangpungtongsungsan on insulin resistance induced by non-alcoholic fatty liver disease. Methods Male 6-week-old C57BL/6 male mice were divided into four groups: control group (Ctrl), high fat diet group (HFF), high fat diet with Bangpungtongsungsan extract administration group (BT1), and high fat diet with double concentration of Bangpungtongsungsan extract administration group (BT2). Each 10 mice were allocated to each group (total of 40 mice). All mice were allowed to eat fat rich diet freely throughout the experiment. To examine the effect of Bangpungtongsungsan, we observed weight changes, lipid blot distributions, PGC-1, $p-I{\kappa}B$, 8-OHdG, p-JNK, total cholesterol and glucose levels. Results Comparing of body weight measurements between 4 groups, weight gain was significantly lower in BT1 and BT2 group than the HFF group. The distribution of lipid blots and positive reaction of PGC-1 were significantly lower in BT1 and BT2 group. The positive reaction of $p-I{\kappa}B$ and 8-OHdG in hepatic tissues was significantly lower in BT1 and BT2 group. The positive reaction of p-JNK in hepatic tissues was significantly lower in BT1 and BT2 group. Total cholesterol and glucose levels were significantly lower in BT1 and BT2 group. Conclusions Bangpungtongsungsan has the effect of improving non-alcoholic fatty liver induced insulin resistance through regulation of lipid metabolism.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.4
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• pp.39-49
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• 2022

In this study, data on traffic volume and weight of small trucks were collected from three National Highways to identify the overload status of small trucks excluded from domestic overloaded vehicle enforcement. These data were classified according to the vehicle type, day of the week, and time of day to analyze the overload distributions by the vehicle total weight. From the analysis results by vehicle type, on average, the overload ratios for trucks of 1.5 tons or less, 2.5 tons or less, 3.5 tons or less were 6.2%, 31.7%, and 13.7%, respectively. In addition, for the same vehicle model, there was a difference by collection point, and the smaller the total weight of the small truck, the higher the overload ratio. From the results according to the day of the week, there was no tendency for the overload ratio to appear high on a specific day, but there was a predictable occurrence pattern at each site. In addition, from the results by the time of day, the overload ratio was the highest on average after lunch (13:00-15:59) at all sites.