• Polymer(Korea)
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• v.38 no.2
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• pp.225-231
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• 2014

The rheological properties of highly concentrated polymer bonded explosive simulant were studied by using poly(ethylene-co-vinyl acetate) with 30 and 60% vinyl acetate (VA) content as a binder, respectively. Calcium carbonate and Dechlorane, whose physical properties are similar to resarch department explosive (RDX)'s, were used as fillers. The suspensions were mixed in a batch melt mixer and it was possible to fill 75 v% at maximum. From dynamic mechanical analysis, Dechlorane showed higher interaction with binder resins than that with calcium carbonate fillers. The effects of microstructural change on the rheological properties of the suspensions were investigated by a plate-plate rheometer with constant shear rate and constant shear stress modes, respectively. The theoretical maximum packing fraction of EVA31/Dechlorane suspension obtained from Krieger-Dougherty equation was 70 v% and it was thought that 2000 Pa was proper shear stress condition for this melt processing.

• Membrane Journal
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• v.16 no.2
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• pp.144-152
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• 2006

Elastomer-clay nanocomposite membranes were prepared by melt intercalation mothod with internal mixer. We are used NMR, Ionomer, SEBS (Styrene Ethylene Butadien styrene Copolymer) as elastomer, and modified clay. Gas barrier property of the elastomer-clay nanocomposites membranes were investigated by a gas permeability of $CO_2,\;O_2,\;N_2$ at room temperature. Gas permeability through the elastomer-clay nanocomposite membranes increased due to increased tortuosity made by intercalation of clay in elastomer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1485-1492
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• 1994

In this paper, we design and implement the Combline Bandpass Filters for the satellite transponder by using the least-squares curve-fitting method. The Combline Bandpass Filters are located front of the mixer and behind of it, which is the component of down converter. Comparing with the filters which have $\lambda$/4 resonance length. Combline Filter has wide range of stop-band by using $\lambda$/8. So, it is useful to the satellite transponder owing to its low mass and small size. The filters described are realized as coupled rectangular coaxial transmission lines. The choice of this type is due to the ease of machining and wide variations in coupling coefficients rather than the use of the round rod resonators. We determine 800 MHz bandwidths for the combline bandpass filters. By using Chebyshev filter function, we design and implement 4-pole combline filters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7A
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• pp.545-551
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• 2012

In this paper, K-band multi-channel receiver was designed and fabricated for low noise amplification and down conversion to L-band. The fabricated multi-channel receiver incorporates GaAs-HEMT LNA(Low noise amplifier) which provides less than a 2 dB noise figure, IR(Image Rejection) Filter for rejection of image frequency, IR(Image rejection) mixer to reject a image frequency and improve an IMD(Intermodulation Distortion) characteristic. Test results of the fabricated multi-channel receiver show less than a 3.8 dB noise figure, conversion gain of more than 27dB, and IP1dB(Input 1dB Gain Compression Point) of -9.5 dB and over.

• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.392-399
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• 2009

The paper concerns the description of the step by step development process of the new fixed blade runner called "Mixer" suitable for the uprating of the Francis turbines units installed at the older low head hydropower plants. In the paper the details of hydraulic and mechanical design are presented. Since the rotational speed of the new runner is significantly higher then the rotational speed of the original Francis one, the direct coupling of the turbine to the generator can be applied. The maximum efficiency at prescribed operational point was reached by the geometry optimization of two most important components. In the first step the optimization of the draft tube geometry was carried out. The condition for the draft tube geometry optimization was to design the new geometry of the draft tube within the original bad draft tube shape without any extensive civil works. The runner blade geometry optimization was carried out on the runner coupled with the draft tube domain. The blade geometry of the runner was optimized using automatic direct search optimization procedure. The method used for the objective function minimum search is a kind of the Nelder-Mead simplex method. The objective function concerns efficiency, required net head and cavitation features. After successful hydraulic design the modal and stress analysis was carried out on the prototype scale runner. The static pressure distribution from flow simulation was used as a load condition. The modal analysis in air and in water was carried out and the results were compared. The final runner was manufactured in model scale and it is going to be tested in hydraulic laboratory. Since the turbine with the fixed blade runner does not allow double regulation like in case of full Kaplan turbine, it can be profitably used mainly at power plants with smaller changes of operational conditions or in case with more units installed. The advantages are simple manufacturing, installation and therefore lower expenses and short delivery time for turbine uprating.

• Journal of Powder Materials
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• v.18 no.3
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• pp.262-268
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• 2011

In order to investigate the microstructure and mechanical properties of WC-10 wt% Co insert tool alloy fabricated by PIM (Powder Injection Molding) process, the feedstock of WC-10 wt% and wax used as a kind of binder were mixed together by two blade mixer. After injection molding, the debinding process was carried out by two-steps. First, solvent extraction, in which the binder was eliminated by putting the specimen into normal hexane for 24 hrs at $60^{\circ}C$, and subsequently thermal debinding which was conducted at $260^{\circ}C$ and $480^{\circ}C$ for 6 hrs in the mixed gas of $H_2/N_2$, respectively. Meantime, in order to compensate the decarburization due to hydrogen, 1.2~1.8% of carbon was added to ensure the integrity of the phase. Finally, the specimens were sintered in vacuum under different temperatures, and the relative density of 99.8% and hardness of 2100 Hv can be achieved when sintered at $1380^{\circ}C$, even the TRS is lower than the conventional sintering process.

• 한국문화재보존과학회:학술대회논문집
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• 2002.02a
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• pp.21-31
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• 2002

Lime-soil consolidations are very important as structural material, bonding material, waterproofing material, and finishing material in korea traditional buildings. In this study, we investigated site application trouble in korea traditional buildings being repaired or restored, and propose following solutions. 1) To diminish quality variation occurred by slaking quick-lime in site, it is desirable to use slaked-lime for lime-soil consolidation. 2) For uniform construction of lime-soil consolidation, we would recommend builders to use mixer to be uniform mixture, premixed type materials and compacting machine in field, 3) and to use rigid suitable temporary construction as scaffold for preventing traditional buildings from additional damage occurred in demolition and construction of a layer of lime-soil consolidation of a roofing. 4) For suitable repair of traditional buildings, it is necessary to specify definitely materials and construction methods suggested by the standard specifications for repair of the cultural property.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.564-568
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• 2004

Restructuring had made it possible to utilize lower value cuts and meat trimmings from spent animals by providing convenience in product preparation besides enhancing tenderness, palatability and value. Milk co-precipitates (MCP) have been reported to improve the nutritional and functional properties of certain meat products. This study was undertaken to evaluate the influence of incorporation of milk co-precipitates at four different levels viz. 0, 10, 15 and 20% on the quality of restructured buffalo meat blocks. Low-calcium milk co-precipitates were prepared from skim milk by heat and salt coagulation of milk proteins. Meat chunks were mixed with the curing ingredients and chilled water in a Hobart mixer for 5 minutes, followed by addition of milk co-precipitates along with condiments and spice mix and again mixed for 5 minutes. Treated chunks were stuffed in aluminium moulds and cooked in steam without pressure for 1.5 h. After cooking, treated meat blocks were compared for different physico-chemical and sensory attributes. Meat blocks incorporated with 10% MCP were significantly better (p<0.05) than those incorporated with 0, 15 and 20% MCP in cooking yield, percent shrinkage and moisture retention. Sensory scores were also marginally higher for meat blocks incorporated with 10% MCP than product incorporated with 15 and 20% MCP, besides being significantly higher than control. On the basis of above results 10% MCP was considered optimum for the preparation of restructured buffalo meat blocks. Instrumental texture profile analysis revealed that meat blocks incorporated with 10% MCP were significantly better (p<0.05) in hardness/ firmness than control although, no significant (p>0.05) differences were observed in cohesiveness, springiness, gumminess and chewiness of both type of samples.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.91-99
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• 2010

A Model of small scale total mixed rations(TMR) plant which can be utilized round bales was developed, tested and analyzed in this study. This study consist of two parts. One is development of a small scale TMR plant model which was already reported at the previous paper. This is the second part of the study. For the study, a series of tests of the model plant were performed and its costs was analyzed. Also, the break-even point of the model plant by comparing with market price of commercial TMR feed was determined. Results of the research are summarized as follows ; As the results of mixing test, the average coefficient of variation(CV) value for mixing of the feed was 13.0 % at the gate of the mixer. The production cost was estimated as 8,298 won/head for dairy cattle farm and 2,495 won/head for beef cattle farm, when producing 8 batch a day. Also, it is recommended to utilize the model plant when farm size is over 79 heads for dairy cattle farm and 113 heads for beef cattle farm. As an overall conclusion, the model plant designed for farm size TMR feed mill will be very useful model for both beef cattle and dairy farms in Korea. Also it is expected that the capital investment for the model plant can be recovered with 8 months compare with purchasing commercial TMR feed if the model plant feeds 1,000 beef cattle approximately.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.562-570
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• 2019

To develop natural-tasting fish paste from the pufferfish Lagocephalus wheeleri, steamed pufferfish paste (SPP) was prepared and its optimal processing conditions, quality metrics, and shelf-life characteristics were examined. SPP was produced by thawing golden threadfin Nemipterus virgatus surimi (FA grade), then adding 10% unwashed pufferfish surimi (PS), 1.5% salt, 8.0% wheat starch, 0.25% calcium carbonate, 0.25% sugar, 0.75% sorbitol, 0.25% polyphosphate, and 12.0% pufferfish hot-water extract (Brix 10°). The meat was ground with a Stephan mixer, molded at low temperature (18℃, 10 h), vacuum packed in a laminated plastic film bag, heat treated with hot water (95℃, 50 min), and cooled. As the amount of PS added increased, the whiteness, gel strength, and shear strength of the SPP decreased slightly. However, the SPP folding test showed no deterioration in the texture. In the sensory evaluation, the SPP received a higher rating for taste, smell, and overall taste than commercial Japanese pufferfish Kamaboko. The total amino acid content of the SPP was 10,262.6 mg/100 g; the major amino acids were aspartic acid, glutamic acid, alanine, valine, leucine, lysine, and arginine. The free amino acid content was 133.0 mg/100 g; the major amino acids were taurine, glutamic acid, glycine, alanine, cystine, and lysine.