• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.36-40
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• 2003

In order to discuss the availability of aerostatic guideways driven by the coreless linear motor to ultra precision machine tools, a prototype of guideway is designed and tested in this research. A coreless linear DC motor with the continuous force of 156N and a laser scale with the resolution of $0.01\mu\textrm{m}$ are used as the feeding system. The experiments are performed on the static stiffness, motion accuracy, positioning accuracy, microstep response and variation of velocity. The guideway also has $0.21\mu\textrm{m}$ of positioning error and $0.09\mu\textrm{m}$ of repeatability, and it shows the stable response against the $0.01\mu\textrm{m}$ resolution step command. The velocity variation of feeding system is less than 0.6%. From these results, it is confirmed that the aerostatic guideway driven by the coreless linear motion is very useful for the ultra precision machine tools.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.225-229
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• 2014

Feeding behavior of Temora turbinata was investigated through laboratory experiments with special emphasis on its food preference and consequent clearance rate on diatom and microbial components given as common natural food assemblage of coastal area (Uchiumi, Uwa Sea, Japan). Among available prey items, T. turbinata showed the highest clearance rate for Thalassiosira spp. ($0.23{\pm}0.08L\;Temora^{-1}day^{-1}$) followed by Chaetoceros spp. ($0.11{\pm}0.03L\;Temora^{-1}day^{-1}$), but clearance rates for other diatom, Nitzschia spp. was lower (0.03 to $0.07L\;Temora^{-1}day^{-1}$). Bacterial abundances showed no response against 24-h feeding of T. turbinata. Feeding of T. turbinata on heterotrophic nanoflagellates (HNF) was apparent when clearance rates of T. turbinata on diatoms were relatively low, but T. turbinata did not consume HNF as well as ciliates with Thalassiosira spp. of which clearance rate was highest. The results suggest that HNF and ciliates are possible supplementary prey item for T. turbinata, but their contribution as food sources can be limited by the presence of other prey items such as preferable diatom species.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.493-498
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• 1994

The response of crossbred Holstein milking cows to the neutralized urea-treated rice straw feeding was investigated. Rice straw was treated with 6% urea for at least 21 days and further with sulfuric acid for overnight to complete the neutralization. The neutralized straw was then sun-dried and its feeding value was compared with that of the dried non-neutralized urea-treated straw. They were fed to the cows with concentrates either by the ration formulation based on the nutrient requirements for milk production recommended by NRC or by the traditional way in which straw was fed ad libitum and concentrates at 1 kg/2 kg of milk production. The results showed that milk production as well as milk composition of cows were not different between neutralized and non-neutralized straw. The feeding of the neutralized straw could significantly reduce the supply of protein-rich feed such as soybean oil meal, and it was demonstrated that ammonium sulfate in the neutralized straw could be utilized as effective as the plant origin protein. The results also suggested that if the traditional feeding method is applied to the dairy cattle, protein content of the supplementing concentrates should be increased to meet the requirement.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.3
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• pp.45-52
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• 2002

This article deals with the introduction of longitudinal instability of liquid rocket (pogo) and the analytical results on the frequency responses of Korean Sounding Rocket (KSR-III) propulsion feeding system. Both the stiffness of bellows and the cavitation volume of venturi affect the frequency response of the feeding system. Especially, bellows has a great roll to reduce the natural frequency of the feeding system. Also, oxidizer and fuel feeding systems of the KSR-III have natural frequencies of about 280Hz and 90Hz, respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.340-344
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• 2000

Microbial oxidation of D-sorbitol to L-sorbose by Acetobacter suboxydans is of commercial importance since it is the only biochemical process in vitamin C synthesis. The main bottleneck in the batch oxidation of sorbitol to sorbose is that the process is severely inhibited by sorbitol. Suitable fed-batch fermentation designs can eliminate the inherent substrate inhibition and improve sorbose productivity. Fed-batch sorbose fermentations were conducted by using two nutrient feeding strategies. For fed-batch fermentation with pulse feeding, highly concentrated sorbitor (600g/L) along with other nutrients were fed intermittently in four pulses of 0.5 liter in response to the increased DO signal. The fed-batch fermentation was over in 24h with a sorbose productivity of 13.40g/L/h and a final sorbose concentration of 320.48g/L. On the other hand, in fed-batch fermentation with multiple feeds, two pulse feeds of 0.5 liter nutrient medium containing 600g/L sorbitol was followed by the addition of 1.5 liter nutrient medium containing 600g/L sorbitol at a constant feed rate of 0.36L/h till the full working capacity of the reactor. The fermentation was completed in 24h with an enhanced sorbose productivity of 15.09g/L/h and a sorbose concentration of 332.60g/L. The sorbose concentration and productivity obtained by multiple feeding of nutrients was found to be higher than that obtained by pulse feeding and was therefore a better strategy for fed-batch sorbose fermentation.

• Journal of the Korean Dietetic Association
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• v.2 no.1
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• pp.81-91
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• 1996

Customer satisfaction concerning foodservice quality characteristics were evaluated by using importance performance analysis(IPA) techniques in employee feeding operations. The purpose of this study were to survey employees' health condition and their food habits, to examine employees' perception of the importance and performance concerning foodservice quality charactertics and to analyze attributes for quality improvement in employee feeding operations. A questionaire for survey was developed and mailed to 1,700 employees and the response rate was 60.8%. Statistical data analysis was done using the SAS programs for descriptive analysis, $x^2$-test, F-test and Fisher's LSD. The results of this study were as follows 1. Most of employees responded that their health condition were generally good. 2. 17.8% of surveyed employees responded that they usually skipped their breakfast. 3. Main reasons of using employee feeding facilities identified were convenience and cheap price of meals. 4. Dissatisfied quality attributes identified were taste of food, atmosphere and location d dinning room, and the quality of food served for breakfast and dinner, 5. Satisfied quality attributes identified were nutritionally balanced meal with variety, competitive managerial skills of dietetian, and quality of food served for lunch.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.249-250
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• 1989

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.416-423
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.225-228
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• 2004

Optimization of fluidized bed granulating conditions for yield, bulk density, and tapped density of powdered milk was determined using response surface methodology. Yield of powdered milk was greatly affected by feeding rate of water, and bulk density and tapped density could be reduced by decreasing of atomization pressure. The optimum conditions for fluidized bed granulating of powdered milk were predicted with 6$0^{\circ}C$ of inlet air temperature, 16 mL/min of feeding rate, and 2.1 bar of atomization pressure. Also 94% of yield 0.350 g/㎤ of bulk density, and 0.446 g/㎤ of tapped density of powdered milk could be obtained by the optimum granulating conditions.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.30-37
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m／min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.