• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.23-29
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• 2023

Among the Additive Manufacturing (AM) technologies, the Binder-Jetting printing technology is a method of spraying an adhesive on the surface of powder and laminate layer by layer. Recently, this technique has become a major issue in the production of large casting products such as ship-building, custom vehicles and so on. In this study, we performed research to make actual mold castings and increase mechanical property by using special sand and water-based binders. For use as a mold, it has a strength of more than 3MPa and permeability. Various experiments were carried out to obtain suitable them. The major process parameters were binder jetting volume, binder types, layer thickness and heat treatment condition. As a result of this study, the binder drop quantity was measured to be about 60 pico-liter, layer thickness was 100㎛ and the heat treatment condition was measured about 1,000℃ and compressive strength were measured to be more than 5MPa. The optimum condition of this experiment was established through actual casting of aluminum. The equipment used in this study was a Freeforms T400 model (SFS Co., Ltd.), and the printing area of 420 * 300 * 250mm and resolution of 600dpi can be realized.

• Food Science and Preservation
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• v.20 no.5
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• pp.621-627
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• 2013

This study was conducted to investigate the effect of Curcuma longa L. powder (CLP) on the quality characteristics of a dumpling shell. Dumpling shell samples were prepared with wheat flour and different amounts of CLP were added to them, after which their instrumental characteristics and sensory evaluation were investigated. The gelatinization temperature of the CLP-wheat flours composite increased, whereas its initial viscosity at $95^{\circ}C$, viscosity at $95^{\circ}C$ after 15 min and maximum viscosity all fell with the increasing CLP content, as measured via amylography. As increasing amounts of CLP were added, the L value decreased, whereas the a and b values increased. With regard to the textural characteristics, the CLP additive became harder, more cohesive and adhesive, and less springy. The DPPH free radical scavenging activity increased significantly as the CLP content increased (p<0.05). Overall, the dumpling shells with 3% CLP were preferred over the other samples, as tested via sensory evaluation.

• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.32-38
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• 1982

This study was carried out to examine the possibility to replace imported wheat flour with taro. Taro and wheat flour were used for the extenders after oven drying($100{\pm}3^{\circ}C$)and pulverized into 80-100mesh minute powder by laboratory willey mill. Urea- and phenol-formaldehyde resin adhesives were used for plywood manufacture, and the extending materials mixed with the extension at the ratio of 10, 20, 30, and 50% to each resin solution. The results obtained at this study were summarized as follows; 1) In dry and wet shear strength of urea-formaldehyde resin adhesive, taro showed very excellent bonding strength compared with wheat flour in all extending ratio. Therefore taro showed the possibility that be usable to taro in place of wheat flour. 2) In dry and wet shear strength of phenol-formaldehyde resin adhesive, in general, wheat flour showed higher bonding strength than taro. But in dry shear strength, taro showed higher shear strength than wheat flour in 30 and 50% extension.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.94-104
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• 2013

Experiments were divided into two parts; one part is to understand the basic properties of high flowable VA/VeoVa-modified cement mortar with different polymer cement ratio (P/C) and the weight ratio of fine aggregate to cement (C:F) and the other part is to investigate the effect of surface water spread on the concrete substrate on adhesion in tension. To understand the basic performance, the specimens were prepared with proportionally mixing VA/VeoVa redispersible powder, ordinary portland cement, silica sand, superplasticizer and viscosity enhancing agent. Here, P/C were 10, 20, 30, 50 and 75% and C:F were 1:1 and 1:3. As the change of P/C and C:F unit weight, flow test, crack resistance and adhesion in tension were measured. Three specimens with good adhesion properties were selected among specimens with different P/C and C:F. The effect of surface water evenly sprayed on concrete substrate on adhesive strength is investigated. The results show that surface water on concrete substrate increases the adhesion in tension of high flowable VA/VeoVa-modified cement mortar and additionally improves the flowability compared to the non-sprayed case.

• Journal of Technologic Dentistry
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• v.35 no.1
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• pp.43-48
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• 2013

Purpose: This study aimed to investigate the shear bond strength for non-precious alloy castings without beryllium, which has been used repeatedly for economical reason. Methods: The Schmitz-Schulmeyer test method was used to evaluate the shear bond strength between the non-beryllium Ni-Cr alloy Vera Bond 2V(AlbaDent, Inc. USA) and the Ceramco 3(Dentstply, York, PA, USA) porcelain powder. The maximum loading and shear bond strength were measured. The average shear strength(MPa) was analyzed with the one-way ANOVA and the Tukey's test( =.05). The fracture specimens were examined using Microscope to determine the failure pattern. Results: The mean shear bond strengths(SD) in MPa were group A(100% new metal) control 28.72(3.31); group B(50% new + 50% reused) 27.28(1.13); group C(all reused) 26.61(5.47). Microscope examination showed that group A and B specimens presented mixed failure, and group C specimens showed adhesive failure. Conclusion: In conclusion, forward this non-precious alloy dose not contain beryllium for how should use a more systematic study and for future advanced research is performed giving effect to be considered desirable.

• Journal of the Korean Wood Science and Technology
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• v.19 no.1
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• pp.71-80
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• 1991

This study was carried out to investigate replaceable species with the conventional sounding board sitka spruce. by comparing the dynamic properties such as density, dynamic Young's modulus and internal friction Dynamic Young's modulus. internal friction of longitudinal and radial direction measured in free mass-free boundary condition for facile vibration analysis and measured by forced vibration method. Dynamical properties of four species were measured on squared plate specimen that the four edges were hung vertically by threads and driven magnetically through an iron piece glued on the specimen, by the use of condenser microphone as vibration transducer, and analyzed by FFT analyzer. The results obtained were as follows: 1. Chaldni method using aluminum powder was proper to identify the vibration mode in the plate vibration and it was possible to verify the resornance mode. 2. It was considered that it was necessary to investigate the influence of adhesive part on the plate vibration when the sounding board was made by two or three small board adhesion. 3. It was considered that plate vibration method, which was a superior to the vibration test of beam, was suitable for selecting suounding board because dynamic Young's modulus and internal friction show different order according to longitudinal and radial direction. 4. Paulownia tomentosa Thunb.) Steudel has been considered to be replaceable species with sitka spruce because it has high dynamic Young's modulus compared with low density, low internal friction, and K value of Paulownia tomentosa (Thunb.) Steudel is greater than that of sitka spruce.

• Journal of the Korean Ceramic Society
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• v.42 no.8 s.279
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• pp.554-560
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• 2005

The engineering ceramic needs the properties of high strength, hardness, corrosion-resistance and heat-resistance in order to withstand thermal shock or applied nonuniform stresses without failure. The densely coated porous ceramics can be used for machine component, electromagnetic component, bio-system component and energy-system component by their high-performances from superior coating properties and light-weight characteristics due to the structure including pore by itself. In this study we controlled the porosity of silica and alumina, $8.2\~25.4\%$ and $23.4\~36.0\%$, respectively, by the control of sintering temperature and starting powder size. We made bilayer structures, consisting of a transparent glass coating layer bonded to a thick substrate of different porous ceramics by a thin layer of epoxy adhesive, facilitated observations of crack initiation and propagation. The elastic modulus mismatch could be controlled using different porous ceramics as the substrate layer. Then we applied 150 N force using WC sphere with a radius of 3.18 mm by Hertzian indentation. As a result, the crack initiation in the coating layer was delayed at lower porosity in the substrate layer, and the damage in the coating layer was relatively smaller at the bilayer structure coated on higher elastic substrate.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.467-472
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• 2002

Long Carbon Nanotubes(CNTs) were cut by diamond lapping film followed by observation using SEM. The paste was prepared by mixing shortened CNT powder, ${\alpha}$-terpineol used as a solvent, and ethylcellulose as a binder. This paste was deposited on glass substrate by screen printing and extruded by syringe. After screen printing, several post-treatments were performed to control the alignment of CNTs perpendicular to the substrate. The deposited CNTs were scratched by sand paper or diamond lapping film. It was also treated by attachment followed by an immediate detachment using the adhesive tape. SEM observation indicates that excellent vertical alignment of CNTs could be achieved by simple post-treatments from the screen printed-CNTs paste. Similar alignment of CNTs is also observed in the as-extruded CNTs paste.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.35-44
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• 2015

Two main parameters were examined such as CSA content and polymer-binder ratio to find effects on the strength, water absorption, chloride ion penetration depth, carbonation depth, length change and chemical resistance of polymer-modified mortar with CSA and EVA polymer powder (EVAPP). As results, compressive, flexural, tensile, adhesive strengths, and length change of the polymer-modified mortar with CSA and EVAPP increases with increasing CSA content and polymer-binder ratio, although the water absorption, chloride ion penetration depth, and carbonation depth decrease with increasing polymer-binder ratio and CSA content, and also the chemical resistance decreases. Such strength and durability development is attributed to the high tensile strength of EVA polymer and the improved bond between cement hydrates and aggregates because of the addition of EVAPP and CSA.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.1
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• pp.226-252
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• 2002

The results of a literature study about the comparison of Oriental-Occidental medicine on the Atopic dennatitis were as follows. 1. In Oriental medicine, Atopic dermatitis belongs to the category of the Naesun(내선), Taeryumchang(胎斂瘡), Eczema(濕疹), Chimumchang(浸淫瘡). In Occidental medicine, the other names of Atopic dermatitis are allergic eczema, IgE dermatitis, flexual eczema etc. 2. In Oriental medicine, the definition of atopic dermatitis includes chang(瘡), sun(선), and pung(風). Occidental medicine, is one of the intrinsic eczema classifications. In fact eczema term circumscribes dermatitis in atopic patients. 3. In Oriental medicine, the etiology and pathogenesis of Atopic dermatitis arose from the state of cogenital defect(稟賦不足), internal accumulation of damp and heat(濕熱內蘊) at first, and then invaded pathogenic wind, damp, heat factors again, and combined endo-exoteric pathogenic factors. So it appears in skin. In Occidental medicine, the etiology and pathogenesis of Atopic dermatitis approaches in genetic, allergic and immunologic, pharmacophysioloic aspects. It is only a hypothesis but there is no known facts about radical aetiology. 4. In Oriental medicine, differentiation of syndromes classifies manifestation aspects, etiology and pathogenesis, and invasion period. In Occidental medicine, it divides into an invasion period, and clinical aspect etc. 5. In Oriental medicine, Internal theraphys of Atopic dermatitis are decoction of ingredients(湯劑), pills(丸), and tablet(片). So, it prescribes as treatments on the ground of differentition of syndrome. In Occidental medicine, there is no radical therapy because Atopic dispositions don't change. But steroid, antihistamine as symptomatic tre atments are generally used in Occidental medicine. 6. In Oriental medicine, external therapies are wet dressings(濕敷), lotion(洗劑), powder(散劑), adhesive plasters(膏劑), oil(油劑), smoking(烟薰法), warm over fire therapy(熱烘療法), acupunture and moxibustion therapy(鍼灸療法).