• 드라이브 ㆍ 컨트롤
• /
• 제14권2호
• /
• pp.23-29
• /
• 2017

In this study, a flexible multi-body dynamic simulation model of a knuckle boom crane is developed to evaluate the stress of spindle and rack gears under dynamic working conditions. It is difficult to predict potential critical damage to a knuckle boom crane if only the static condition is considered during the development process. To solve this issue, a severe working scenario (high speed with heavy load) was simulated as a boundary condition for testing the integrity of the dynamic simulation model. The crane gear model is defined as a flexible body so contact analysis was performed. The functional motion of a knuckle boom crane is generated by applying forces at each end of the rack gear, which was converted from hydraulic pressure measured for the experiment. The bending and contact stress of gears are theoretically calculated to validate the simulation model. In the simulation, the maximum stress of spindle and rack gears are observed when the crane abruptly stops. Peak impact force is produced at the contact interface between pinion and rack gears due to the inertia force of the boom. However, the maximum stress (bending/contact) of spindle and rack are under the yield stress, which is safe from damage. By using the developed simulation model, the experiment process is expected to be minimized.

• Korean Chemical Engineering Research
• /
• 제47권3호
• /
• pp.386-393
• /
• 2009

본 연구는 도심녹지의 대기질 영향을 정량적으로 해석하기 위해 수행되었다. 도심의 '근린공원 녹지'가 가스상 오염물질인 '질소산화물'과 '황산화물'에 미치는 영향을 분석하였으며, 이를 위해 녹지의 대기환경영향평가 모델링시스템이 개발되었다. 모델링은 서울 도심의 대표적 근린공원이라 할 수 있는 종로구의 파고다 공원 인근지역을 대상으로 수행되었다. 모델링 결과, 도시 근린공원의 수목은 자체적으로 오염물질을 흡수 제거하여 대기질을 개선시키는 기능이 크다고는 볼 수 없지만, 상대적으로 친환경적인 토지이용형태(배출원이 거의 없고, 해당지역 및 주변지역에서 원활한 기류소통 촉진)를 유지함으로서 대기환경 악화를 억제하는 효과는 탁월한 것으로 나타났다. 대기오염이 심한 도시지역에서의 대기정책은 오염원 추가건설 제어를 위한 녹지보호정책을 우선적으로 고려해야 할 것으로 판단된다.

• 토지주택연구
• /
• 제8권2호
• /
• pp.33-53
• /
• 2017

The UK Government's approach to how to deliver regeneration in its towns and cities has changed considerably in recent years. Traditionally, urban regeneration policy focused on reversing physical, economic and social decline in an area where market forces would not do this without intervention. Since 2010 urban regeneration has become a vital part of the Government's approach to increasing local growth and competitiveness and building a strong and balanced economy. The current emphasis is on a place-based approach to regeneration that builds on the particular strengths of different places to drive growth and addresses the factors that hold them back. This paper outlines the key features of current UK urban regeneration policy and how interventions to support regeneration and growth are being pursued at different spatial scales to ensure all parts of the country benefit. They include pan regional initiatives like the Northern Powerhouse and Midlands Way, to groups of local authorities operating at a sub regional level (combined authorities/city regions), Local Enterprise Partnerships, and a variety of smaller scale programmes delivering regeneration in areas of economic and social decline. The paper explains some of the policy instruments and funding programmes available to support regeneration, and provides case studies of some major urban regeneration projects that illustrate the new approach including housing and infrastructure improvements like the planned High Speed Rail 2 line. These are supporting regeneration through the creation of strategic partnerships involving government, places and investors. The paper concludes with some lessons from past and future regeneration schemes to improve their effectiveness and impact on places and enhance local growth potential.

• Asian Journal of Atmospheric Environment
• /
• 제6권1호
• /
• pp.1-13
• /
• 2012

To identify the primary factor affected the decreased $PM_{10}$ concentration in Seoul which is the capital city of Korea, wind speed and emissions in 2003 and 2004 were analyzed. The level of air pollution is intense in Seoul and continually increased since the late 1990s. However the concentration of $PM_{10}$ has been greatly declined recently. In particular, the concentration of $PM_{10}$ decreased 14% in 2003 and 2004 excluding the Asian dust periods. It is suggested that the major factors for the decrease are differences in wind speed between the two years and the period of constant breeze. In 2003, intense Asian dust events happened frequently and it increased the concentration of total $PM_{10}$. The intense dust events were influence by the speed and duration of the wind. It is considered that the meteorological condition was the primary drive for the change of the concentration of $PM_{10}$. The decreased emissions seem to be the additional factor for the change in the concentration of $PM_{10}$.

• 한국운동역학회지
• /
• 제22권4호
• /
• pp.421-428
• /
• 2012

The purpose of this study was to verify the effects of developed assisting wear which maximize trunk(back) muscle's stretch-shortening effect during backswing and downswing for increasing golf ball carrying distance. Design and fabrication of assistive wear were performed based on the results of analyzed data of trunk EMG activity from the golf drive swings of elite professional male golfers during back swing and downswing phases. After the prototype of wear was produced, surface EMG and Flight scope tests were conducted to verify the effectiveness of the wear for increasing distance to the professional golfers. Results indicated that wearing trial showed significant longer carry distance than the non-wearing trial(p<.001). The carry distance of wearing trial showed an average 229 m compared to the non-wearing trial, the average 225 m. The swing with wearing also produced significantly faster ball speed than the trial without wearing(p<.05). Average 245 Km/h and 244 Km/h were produced for the swing with and without wearing trails, respectively. EMG results also indicated that the muscle activity of left psoas was significantly increased for wearing trial during downswing and near the impact. Thus, this may affect positively to increase club head speed. The activity of the left latissimus dorsi was dramatically increased during the final stage of swing. This generates elongation effect for longer follow-through and increased impulse between club and ball so eventually valid assistance to increase carry distance. Therefore, the developed assisting wear was proved to be effective tool for increasing golf ball carry distance with maximizing trunk(back) muscle's stretch-shortening effect during backswing and downswing.

• Biomolecules & Therapeutics
• /
• 제28권1호
• /
• pp.98-103
• /
• 2020

Marfan syndrome (MFS), a connective tissue disorder caused by mutations in the fibrillin-1 (Fbn1) gene, has vascular manifestations including aortic aneurysm, dissection, and rupture. Its vascular pathogenesis is assumed to be attributed to increased transforming growth factor β (TGFβ) signaling and blockade of excessive TGFβ signaling has been thought to prevent dissection and aneurysm formation. Here, we investigated whether galunisertib, a potent small-molecule inhibitor of TGFβ receptor I (TβRI), attenuates aneurysmal disease in a murine model of MFS (Fbn1^C1039G/+) and compared the impact of galuninsertib on the MFS-related vascular pathogenesis with that of losartan, a prophylactic agent routinely used for patients with MFS. Fbn1^C1039G/+ mice were administered galunisertib or losartan for 8 weeks, and their ascending aortas were assessed for histopathological changes and phosphorylation of Smad2 and extracellular signal-regulated kinase 1/2 (Erk1/2). Mice treated with galunisertib or losartan barely exhibited phosphorylated Smad2, suggesting that both drugs effectively blocked overactivated canonical TGFβ signaling in Fbn1^C1039G/+ mice. However, galunisertib treatment did not attenuate disrupted medial wall architecture and only partially decreased Erk1/2 phosphorylation, whereas losartan significantly inhibited MFS-associated aortopathy and markedly decreased Erk1/2 phosphorylation in Fbn1^C1039G/+ mice. These data unexpectedly revealed that galunisertib, a TβRI inhibitor, showed no benefits in aneurysmal disease in MFS mice although it completely blocked Smad2 phosphorylation. The significant losartan-induced inhibition of both aortic vascular pathogenesis and Smad2 phosphorylation implied that canonical TGFβ signaling might not prominently drive aneurysmal diseases in MFS mice.

• 산경연구논집
• /
• 제9권1호
• /
• pp.89-97
• /
• 2018

Purpose - The Regional Comprehensive Economic Partnership (RCEP) among 16 countries including South Korea, the largest free trade agreement in the Asia-Pacific region, will be concluded next year. The participating countries decided to pursue a comprehensive and high -quality agreement, while ensuring flexibility considering development level of each country. In this study, trade structures between nations from 2005 through 2016 were examined to see the impact that this agreement will have on Korea and to come up with effective countermeasures. Research design, data, and methodology - The method of analysis includes the analysis of the trade matrix, which is useful for identifying the dependency of the individual countries on the market in the region and the reciprocal dependency of the member countries on the market, and the index of intensity of trade, which is useful for figuring out the share of trade between the parties in total trade. Results - The results showed that first, the international trade coefficients of Vietnam and Philippines are higher than those of China and Japan. Secondly, the international inducement coefficients between China and Japan were high, and that between Indonesia and Burma were low, indicating that Korea's exports did not have much effect on export increase of these countries. Third, as a result of analyzing Korea's trade intensity, it was found that export intensity and import intensity were greater than 1 in Vietnam and Philippines, which shows that there is a high degree of relational bond with these countries. India and Laos countries still have a low level of relational bond, which indicates that there is room for improvement in economic relations when the agreement is concluded. After the signing of the agreement in the future, more diverse industrial structures should be continuously studied. Conclusions - The analysis of trade matrix, trade structure, trade inducement coefficient and trade intensity between Korea and RCEP participating countries shows that the majority of the countries have the high level of economic relationship with Korea. Korea should drive a harder bargain when negotiating the terms of the RCEP, in comparison with the level of the existing FTA agreement excluding Japan.

• 드라이브 ㆍ 컨트롤
• /
• 제14권4호
• /
• pp.1-8
• /
• 2017

The Down-the-Hole hammer is one of the pneumatic drill equipment used for grinding, drilling, and mining. One the advantages of which is that a reduction work efficiency at deep site are relatively small compared to other drilling methods. Due to the large vibration in the underground area, it is difficult to measure the performance of the hammer, and hammer testing requires substantial production cost and operating expenses so research on the development of the hammer is insufficient. Therefore, this study has developed a dynamic simulation model that apprehends the operating principles of an 8-inch DTH hammer and calculates performance data such as performance impact force, piston speed, and BPM. By using the simulation model, design factors related to strike force and BPM were selected, and the influence of each design factors on performance was analyzed through ANOVA analysis. As a result, be the most important for BPM and the strike force are position of upper port that push the piston in the direction of the bit and in BPM, the size of the empty space between the bits and the piston is the second most important design factor.

• 한국기계가공학회지
• /
• 제20권10호
• /
• pp.19-26
• /
• 2021

In fine-particle injection processing, hard fine particles, such as silicon carbide or aluminum oxide, are injected - using high-pressure air, and a small amount of material is removed by applying an impact to the workpiece by spraying at high speeds. In this study, a two-axis stage device capable of sequence control was developed to spray various shapes, such as circles and squares, on the surface during the micro-particle jetting process to understand the surface-shape micro-particle-processing characteristics. In the experimental device, two stepper motors were used for the linear movement of the two degree-of-freedom mechanism. The signal output from the microcontroller is - converted into a signal with a current sufficient to drive the stepper motor. The stepper motor rotates precisely in synchronization with the pulse-signal input from the outside, eliminating the need for a separate rotation-angle sensor. The major factors of the processing conditions are fine particles (silicon carbide, aluminum oxide), injection pressure, nozzle diameter, feed rate, and number of injection cycles. They were identified using the ANOVA technique on the design of the experimental method. Based on this, the surface roughness of the spraying surface, surface depth of the spraying surface, and radius of the corner of the spraying surface were measured, and depending on the characteristics, the required spraying conditions were studied.

• Nuclear Engineering and Technology
• /
• 제51권7호
• /
• pp.1738-1748
• /
• 2019

Previous research has shown that the inclined condition has an impact on the natural circulation (natural circulation) mode operation of Floating Nuclear Power Plant (FNPP) mounted on the movable marine platform. Due to its compact structure, small volume, strong maneuverability, the Integral Pressurized Water Reactor (IPWR) is adopted as marine reactor in general. The OTSGs of IPWR are symmetrically arranged in the annular region between the reactor vessel and core support barrel in this paper. Therefore, many parallel natural circulation loops are built between the core and the OTSGs primary side when the main pump is stopped. and the inclined condition would lead to discrepancies of the natural circulation drive head among the OTSGs in different locations. In addition, the flow rate and temperature nonuniform distribution of the core caused by inclined condition are coupled with the thermal hydraulics parameters maldistribution caused by OTSG group operating mode on low power operation. By means of the RELAP5 codes were modified by adding module calculating the effect of inclined, heaving and rolling condition, the simulation model of IPWR in inclined condition was built. Using the models developed, the influences on natural circulation operation by inclined angle and OTSG position, the transitions between forced circulation (forced circulation) and natural circulation and the effect on natural circulation operation by different OTSG grouping situations in inclined condition were analyzed. It was observed that a larger inclined angle results the temperature of the core outlet is too high and the OTSG superheat steam is insufficient in natural circulation mode operation. In general, the inclined angle is smaller unless the hull is destroyed seriously or the platform overturn in the ocean. In consequence, the results indicated that the IPWR in the movable marine platform in natural circulation mode operation is safety. Selecting an appropriate average temperature setting value or operating the uplifted OTSG group individually is able to reduce the influence on natural circulation flow of IPWR by inclined condition.