• Tribology and Lubricants
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• v.36 no.1
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• pp.11-17
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• 2020

In manufacturing operations, oil plays a crucial role in reducing friction and wear among interacting surfaces at varying velocities, loads, and temperature. Hydrocarbon oil is considered the origin of lubrication oils. However, this base oil has been limited in its use as it is a principal cause of pollution. This research focuses on identifying a biodegradable base oil lubricant that possesses a stable coefficient of friction and viscosity with temperature. Friction analysis is conducted by employing a pin on a disk tribotester with a fixed load of 10 N at varying sliding speeds ranging from 0.06 m/s to 0.34 m/s. Oil viscosity analysis is perfomed at room temperature by using a rotary viscometer. Tests are performed using canola oil and paraffin oil as lubricants. The results indicate that the viscosity of canola oil is more efficient than paraffin oil. The non-dimensional characteristic number according to the Stribeck curve reveals an elastohydrodynamic lubrication regime with canola oil lubrication. A comparison of both lubricants reveals that, the friction efficiency of canola oil and paraffin oil does not differ considerably. However, the friction in canola oil is observed to decrease more than that in paraffin oil at an elevated sliding speed. The tests confirm that canola oil is potent in minimizing the friction coefficient of SCM440 bodies interacting with one another as well as acted upon by load.

• Korean Journal of Veterinary Research
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• v.29 no.3
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• pp.383-391
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• 1989

This study was carried out to diagnostic test for bovine mastitis by the determination of adenosine triphosphate (ATP) based on firefly bioluminescence. The results obtained are follow; 1. The infection rate of bovine mastitis investigated with 521 cows in 47 dairy farms were found to be 3.6% of clinical form and 44.1% of subclinical form according to the degree of infection. 2. The light yield produced in firefly bioluminescence system was proportional to the concentration of ATP giving stright line within the range of 100PM~1uM. 3. When the number of somatic cell in milk was determined by the ATP assay and compared with three conventional methods such Fossomatic, California mastatic test (CMT), and rolling ball viscometer (RBV), it was shown that r=0.92 for Fossomatic, 0.63 for CMT and 0.7 for RBV. 4. The microorganisms causing mastitis were isolated Staphylococcus sp. (53.3%), Streptococcus sp. (17.9%), Micrococcus sp. (13.5%), Gram negative bacilli (6.3%), Gram positive bacilli (5.5%) and Yeast-like fungi (5.4%). 5. The endogeneous ATP levels of bacteria in a raw milk determined by the firefly bioluminescence system and compared with the results of the conventional methods. The correlation was 0.88 for raw milk.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.9-18
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• 2014

PURPOSES : The objective of this study is to evaluate the applicability of the pitch, which is produced during SDA petroleum upgrading process, as a pavement paving material. In order for the purpose, the physical and chemical properties of the pitch are analyzed, and then the various plasticizers are applied in the pitch. METHODS : Two types of pitch are selected from oil refinery companies, which are owned the SDA petroleum upgrading process. Also, two types of asphalt binders, PG 64-22 and PG 58-22, are employed to compare with the pitch because these two types of asphalt binders are currently used as paving materials. For the chemical property of the pitch, the composition of SARA (Saturate, Aromatic, Resin, Asphaltene), the elementary composition, and the functional group are analyzed. For the physical property of the pitch, the basic material property tests, such as penetration test, softening point test, flash point test, ductility test, and rotational viscometer test, are performed. Also, the DSR (Dynamic Shear Rheometer) test and the BBR (Bending Beam Rheometer) test are conducted using asphalt binder specimens obtained by both short term aging (Rolling Thin Film Oven, RTFO) and long term aging (Pressure Aging Vessel, PAV) processes. The rheological property of each pitch type is evaluated as a function of temperatures and loading cycles. PG 64-22 asphalt binder is used as a control material. RESULTS AND CONCLUSIONS : The Pitch may not be suitable for the pavement paving material without modifications, but the pitch can be used as alternatives of modified addictive or asphalt. If low molecular component, such as saturate and aromatic components, are added in the pitch based on the development of various plasticizers, it has a strong possibility for the pitch to be used as a alternative. However, in order to verify the performance property of the pitch, further research is needed.

• Tribology and Lubricants
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• v.24 no.4
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• pp.190-195
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• 2008

Many researchers have tried to improve the tribological characteristics of lubricant by adding various nano particles in the base lubricant. But the reliability evaluation of the lubricants are rarely performed in its real operation condition. In this study, the physical property and the tribological characteristics of the graphite nano lubricant were evaluated and compared with raw lubricant after thermal degrading. In order to evaluate the tirbological characteristics, the disk-on-disk tribotester was adopted to measure the friction coefficient of the graphite nano lubricants. Also the temperature variations of friction surfaces were measured by the thermocouple installed on the fixed plate in the test chamber of the tribotester. The kinematic viscosity was measured using a capillary viscometer on the temperatures of 40, 60 and $80^{\circ}C$. The results showed that the graphite nano lubricant had lower friction coefficient and less wear on the friction surfaces than raw lubricant. After thermally degrading, the friction coefficients of graphite nano lubricant increased, but the friction coefficients after thermal degradation were still maintained lower than those of raw lubricant.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.307-311
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• 2000

Sauces are various combination of ingredients mixed together, usually cooked, and in some stage of liquidity. Sauces are used to enhance the flavor of food dishes and to hold ingredients together while a food dish is being cooked. A cooked sauce is combination of a fat, thickener, and liquid. The degree of thickness of the sauce will vary with the proportions of the ingredients. the gelling characteristics of the thickener, and the length of the cooking time. The purpose of this study was to investigate the sensory properties and viscosity of a medium Bechamel sauce differing from cooking methods and ratio of raw materials. Objective evaluation was done by viscometer and line spread chart. Sensory evaluation was done by a panel of 8 judges majoring in food and nutrition. Viscosity of Bechamel sauce was decreased by increasing the amount of milk. Spreadability was increased by increasing the amount of milk, Vice versa. As a result of the sensory evaluation for Bechamel sauce made with various levels of milk, Bechamel sauce having mixture ratio of 1 butter, 1 flour, and 17 milk was the most preferable. Sauteing onion with butter was the most desirable method.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.209-215
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• 2011

In this study, for efficiency enhancement of low temperature heat exchanger, the thermal conductivity and the viscosity of carbon nanofluids and oxidized carbon nanofluids were measured at $10^{\circ}C$ and $25^{\circ}C$, respectively. Carbon nanofluids were made by ultrasonic-dispersing ones in distilled water after Multi-Walled Carbon Nanotubes (MWCNTs) mixed Sodium Dodecyl Sulfate (SDS, 100 wt%), Polyvinyl pyrrolidone (PVP, 300 wt%) each. Oxidized carbon nanofluids were made by ultrasonic-dispersing Oxidized Carbon Nanotubes (OMWCNTs) in distilled water. The thermal conductivity of carbon nanofluids was measured by using a transient hot-wire method. The viscosity was measured by using a digital viscometer. As a result, the thermal conductivity of oxidized carbon nanofluids was the highest of those compared and the other carbon nanofluids at the same mixture ratio and temperature, and the viscosity was measured the lowest of those compared and the other carbon nanofluids.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2318-2324
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• 2017

Quantum cryptography, which is emerging as a next generation password, is being studied by quantum cryptographic transfer protocols and quantum secret communication. Quantum key transfer protocol can be used in combination with the modern password because of the inefficiency of the use of the password, or the use of OTP(one time password). In this paper an algorithm for direct communication by means of direct cryptographic communications rather than quantum keys. The method of implementing quantum secure direct community was adopted using 2-channel methods using Einstein gravity field. Two channels were designed to adopt a quantum secret communication protocol that applies time delay between 2-channels of channel to apply time difference between 2-channels. The proposed time delay effect reflects the time delay by reflecting the gravitational lensing phenomenon. Gravity generator with centrifugal acceleration is incorporated in the viscometer, and the time delay using this implies the correlation between the variance of the metametry.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.55-63
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• 2015

PURPOSES : The objective of this study is to investigate the properties of recycled asphalt binders with five different rejuvenators, in order to evaluate the applicability of the recycled asphalt binders compared with the original asphalt binder. METHODS : In order to simulate recycled asphalt binders, fresh asphalt binders are aged by various Superpave aging procedures, such as the rolling thin-film oven (RTFO) and the pressure aging vessel (PAV). Then, selected rejuvenators are added to the aged asphalt binders in the amount of 5%, 10%, and 15%. The asphalt binder properties are evaluated by the dynamic shear rheometer (DSR), the rotational viscometer (RV), and the bending beam rheometer (BBR). In this study, AP-5 (penetration grade 60-80, PG 64-16) asphalt binder is used. A total of five types of rejuvenators are employed. RESULTS AND CONCLUSIONS : When considering aged asphalt without a new asphalt binder, it seems that the percentage of rejuvenator used in Korea is a bit too low, and that it fails to possess the characteristics of the original binder. From the current practice of evaluating the properties of recycled binder based on penetration ratio only, the amount of rejuvenator required is similar for the long-term-aged binder, but is excessive for the longest-term aged binder, causing deterioration of workability and stiffness of the recycled binder.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.974-978
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• 2000

The vane method was used to measure yield stresses of five commercial kochujang samples under a controlled shear-rate operating condition. Magnitudes of vane yield stress were higher than those of yield stress using Casson model with a concentric cylinder viscometer. Magnitudes of vane yield stresses showed great differences between the static $({\sigma}_s)$ and dynamic yield stresses $({\sigma}_d)$ of kochujang samples with undisturbed structure (UDS) and with broken down structure (BDS). A dimensionless yield number $(N{\sigma}_o)$ was determined from the ratio of ${\sigma}s$ to ${\sigma}d$ in order to describe the existence of temporary structure of kochujang.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.317-320
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• 2008

In recent year, the ultra high strength concrete has highly increased and been used in many parts of the world. However, the viscosity of the ultra high strength concrete is high because of a low water to binder ratio (w/b). So that in this pater, the shear stress and the shear strain rate are directly measured by the viscometer in order to estimate the rheological properties of the ultra high strength concrete and a linear regression analysis was carried out to determine the plastic viscosity and the yield stress as slope. According to the test results, the yield stress and plastic viscosity are correlated to slump-flow, V-funnel flow time, O-lot flow time