• Ocean Systems Engineering
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• v.14 no.1
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• pp.53-72
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• 2024

The interaction of the blade of surface-piercing propellers (SPPs) with the water/air surface is a physical phenomenon that is difficult to model mathematically, so that such propellers are usually designed using empirical approaches. In this paper, a newly developed mechanism for measuring the torque of SPPs in an open water circuit is presented. The mechanism includes a single-component load cell and a deformable torque sensor to detect the forces exerted on the propeller. Deformations in the sensor elements lead to changes in the strain gauge resistance, which are converted into voltage using a Wheatstone bridge. The amplified signal is then recorded by a 16-channel data recording system. The mechanism is calibrated using a 6-DoF calibration system and a Box-Behnken design, achieving 99% accuracy through multivariate regression and ANOVA. Finally, the results of performance tests on a 4-blade propeller were presented in the form of changes in the torque coefficient as a function of feed rate. The results show that the new mechanism is 8% more accurate than conventional empirical methods.

• International Commerce and Information Review
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• v.15 no.3
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• pp.313-332
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• 2013

Large tundra of the Russian Empire, has rich resources and science and technology, and a huge domestic market potential is rapidly changing. Based on the abundant energy resources such as oil, gas, and minerals, as foreign trade is active, the huge capital is moving. And commitment the active SOC by improving laws and regulations and changes in the structure of the Russian economy. One of them pushed the WTO since 1993, 19 years to see fruition join the WTO (World Trade Organization). As the official entry into force August 22, Russia, July 10, 2012, Congress passed the treaty after joining the WTO and of the 156th WTO member countries, was officially join. As the WTO, Russia has the world's 11th-largest economy in the steel tariffs from 30% to 15% are exported to Russia, South Korea Car TV parts from 10% to 0%, reduced from 20% to 5% Korean export companies to export to Russia, etc., is expected to become the new land of opportunity. Russia hopes the changes improve the investment environment, the service industry, manufacturing revitalization the macroeconomic sectors of the economy through the WTO, and forecast, but the consumption increased revenue due to tariff cuts, falling import prices and the real economy, and weak manufacturing base. On the one hand, the perspective of concern. In conclusion, Russia joining the WTO, and the feed to improve the fairness and transparency of the market opening, the Russian advance in Korean companies be facilitated and strong complementary cooperation, especially in manufacturing is expected. In this paper, after Russia joining the WTO, trade liberalization, and ready for a new era of economic cooperation between Korea and Russia, at the point of expanding openness to propose strategies to analyze the problems of Korean companies during the Russian advance.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.851-860
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• 2015

The objective of this study was to manufacture the wood based roughage using lumber from thinning of oak and pitch pine (Pinus rigida). And the study also aimed to investigate a feed value evaluation of wood based roughages. To investigate the optimization condition of steam-digestion treatment for roughage, the wood chips of oak and pitch pine were steam-digestion treated at $160^{\circ}C$ under pressure 6 atm depending on treatment times (60 min, 90 min and 120 min) followed by the content of essential oils analyzed. The essential oil content of steam-digestion treated roughages for 90 min and 120 min were under 0.1 mL/kg. The evaluation of feed value was carried out from steam-digestion treated roughages for 90 min through feed chemical composition analysis, NRC (National research Council) modeling, ruminal degradability analysis and relative economic value analysis. The feed chemical compositions including DM (dry mater), CP (crude protein), EE (ether extract), NDF (neutral detergent fiber), ADF (acid detergent fiber), ADL (acid detergent lignin), NFC (nonfiber carbohydrate) in oak roughage were 95.4, 1.36, 3.11, 90.05, 83.85, 17.33, 6.50%, respectively, and in pitch pine roughage were 94.37, 1.33, 5.48, 87.89, 86.88, 30.56, 6.32%, respectively. Both roughages showed low level of protein and very high level of NDF. The TDN (total digestible nutrient) levels using NRC (2001) model in oak and pitch pine roughages were 40.55, 31.22%, respectively. The ruminal in situ dry matter degradability was higher in oak roughage (23.84%) than in pitch pine roughage (10.02%). The economic values of oak and pitch pine rough-ages were 235, and 210 \, respectively.

• Composites Research
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• v.24 no.4
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• pp.23-28
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• 2011

Recently CFRP laminate joints process by bolts and nets are developed rapidly in aircraft industries. However, there are serious drawback during jointing process. Many hole processes are needed for the manufacturing and structural applications using composite materials. Generally, very durable polycrystalline crystalline diamond (PCD) drill has been used for the CFRP hole process. However, due to the expensive price and slow process speed, chemical vapor deposition (CVD) diamond drill has been used increasingly which are relatively-low durability but easily-adjustable process speed via drill shape change and price is much lower. In this study, the comparison of hole process between PCD and CVD diamond coated drills was done. First of all, CFRP hole processbility was evaluated using the equations of hole processing conditions (feed amount per blade, feed speed). The comparison on thermal damage occurring from the CFRP specimen was also studied during drilling process. Empirical equation was made from the temperature photo profile being taken during hole process by infrared thermal camera. In addition, hole processability was compared by checking hole inside condition upon chip exhausting state for two drills. Generally, although the PCD can exhibit better hole processability, hole processing speed of CVD diamond drill exhibited faster than PCD case.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1760-1766
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• 2009

Physical properties of Yukwa base extruded with glutinous rice flour, rice flour, defatted soy flour, and salt using an twin-screw extruder were investigated. The ingredients were extruded at various moisture contents (16-18%), screw speeds (300 & 400 rpm) at 43.4 kg/hr feed rate. Length and specific volume of Yukwa base increased with decreasing moisture contents. Hunter's color L* values of Yukwa base was higher whereas $a^*\;and\;b^*$ values were lower with increasing moisture content. Water absorption index of Yukwa base increased with increasing moisture contents. X-ray diffraction of Yukwa base showed B type moisture content of 16% and 17% while it showed A type moisture content of 18%. Degree of crystallinity and breaking strength of Yukwa base were the lowest in the moisture content of 16% while the lowest value for hardness was found in the moisture content of 16% and of 17% with screw speed 400 rpm for all samples. In the microstructure of cross section of Yukwa base, air cell size was larger and cell wall was thicker as moisture content increased. The sensory evaluation of the Yukwa base showed that color and flavor were not significantly different among samples, while taste, appearance, mouth feel, and overall preference were higher as moisture contents decreased.

• Tribology and Lubricants
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• v.34 no.3
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• pp.84-92
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• 2018

Bearings are essential for reducing vibration and wear, in order to achieve high durability and increase longevity. White metal treatment of tilting pads via centrifugal casting method has the possibility of increasing durability. However, this manufacturing method has drawbacks such as long processing time, high defect rate, and harmful health effects. Laser cladding deposition technique is a powerful method that can address these issues by decreasing the processing time and providing good adhesion. In this study, we suggest optimum conditions for laser cladding deposition that can be used in industrial applications. We deposited a soft white metal layer on SCM440 that is primarily used in shafts to minimize wear of bearing pads. During the laser deposition process, we controlled factors such as laser power, powder feed rate, and laser head speed to determine the optimum conditions. In addition, we measured the hardness using micro Vickers, and performed field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and friction tests to investigate the mechanical properties and surface characteristics for different parameters. Based on the experimental results, we suggest that laser power, powder feed rate, and laser head speed of 1.3 kW, 2.5 rpm, and 10 mm/s, respectively, constitute the optimum conditions for producing white metals using laser cladding.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.44-52
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• 2002

Low temperature thermal desorption (LTTD) has become one of the cornerstone technologies used for the treatment of contaminated soils and sediments in the United States. LTTD technology was first used in the mid-1980s for soil treatment on sites managed under the Comprehensive Environmental Respones, Compensation and Liability Act (CERCLA) or Superfund. Implementation was facilitated by CERCLA regulations that require only that spplicable regulations shall be met thus avoiding the need for protracted and expensive permit applications for thermal treatment equipment. The initial equipment designs used typically came from technology transfer sources. Asphalt manufacturing plants were converted to direct-fired LTTD systems, and conventional calciners were adapted for use as indirect-fired LTTD systems. Other innovative designs included hot sand recycle technology (initially developed for synfuels production from tar sand and oil shale), recycle sweep gas, travelling belts and batch-charged vacuum chambers, among others. These systems were used to treat soil contaminated with total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs), pesticides, polychlorinated biphenyls (PCBs) and dioxin with varying degrees of success. Ultimately, performance and cost considerations established the suite of systems that are used for LTTD soil treatment applications today. This paper briefly reviews the develpoment of LTTD systems and summarizes the design, performance and cost characteristics of the equipment in use today. Designs reviewed include continuous feed direct-fired and indirect-fired equipment, batch feed systems and in-situ equipment. Performance is compared in terms of before-and-after contaminant levels in the soil and permissible emissions levels in the stack gas vented to the atmosphere. The review of air emissions standards includes a review of regulations in the U.S. and the European Union (EU). Key cost centers for the mobilization and operation of LTTD equipment are identified and compared for the different types of LTTD systems in use today. A work chart is provided for the selection of the optmum LTTD system for site-specific applications. LTTD technology continues to be a cornerstone technology for soil treatment in the U.S. and elsewhere. Examples of leading-edge LTTD technologies developed in the U.S. that are now being delivered locally in global projects are described.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.9-14
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• 2013

Although the mealworm larva (Tenebrio molitor) is high protein source, aversion feature of the larva made it difficult for consuming as a food. In this study, we established optimal powder manufacturing process for T. molitor larva for using as a novel food. For this purpose, it should be feed with the bran sterilized by water vapor for 3-5 days, starved without water or food for 3 days, and then the larvae were sterilized before freeze-drying. The sterilized T. molitor was lyophilzed and grinded by a blender. A safety of the powder as a food was validated by evaluation of Raw 264.7 macrophage cytotoxicity using MTS assay. As above results, we propose that optimal powder manufacturing process established in this study can be used in industrial production of T. molitor as a novel food.

• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.46-51
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• 2014

The purpose of this paper is to study of the vehicle lamp manufacturing system composing ultrasonic waves connection process. Making lamp assembly plant, it was produced in the separate process as the injection molding, ultrasonic waves bonding, annealing in the constant temperature, lamp assembling and packing. But the improvement method producing the lamp was added with one-step process by one automation technique. As a result, welding with ultrasonic waves process, the method decreased the energy consumption and noise during ultrasonic waves welding. Therefore, this method used the mathematics modeling for checking validity, it selected the stability and suitable controller using transfer function of plant and bode chart. In this study, the $180^{\circ}$ revolution control system to turn injection part upside down was $M_{eq}\;lcos{\theta}(t)$ because of gravity influence. It effected to unstable condition a system. For solving this problem, it aimed the linearization and stabilization of system by elimination $M_{eq}\;lcos{\theta}(t)$ as applying Free-forward control technique.

• Korean Business Review
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• v.19 no.2
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• pp.23-46
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• 2006

In modern economic societies, individuals are governed by organizations and they managed their daily lives in one way or another. through such organizations. All activities of the organizations are carried out by the job performance of individuals. Job is a very important factor for both individuals and organizations. The study is the explore. the effect of job characteristics and organizational characteristics on the job satisfaction in the small- and medium- sized firms in Namdong und Banwool Area. Job characteristics and organizational justice were hypothesized to be positively related to job satisfaction. To examine the influence of job characteristics and organizational justice on job satisfactions, data were collected from 320 employees of the small- and medium- sized manufacturing companies in Namdong und Banwool Area. This research took independent variables as the core job characteristics of the job characteristic theory such as skill variety, job stagnation, job importance, autonomy, feed back, and organizational justice as distributive and procedural justice. As a result, I can make the following suggestions. First, The Results show that job characteristics and organizational justice were significant and important predictors of job satisfaction. Secondarily, to raise the job desire of organizational members, job must be designed in such a way that the members can highly recognize their job characteristics.