• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.267-272
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• 2006

Butterfly valves have been used for shut-off and throttling-control application in many industrial fields. Recently, they are frequently used for cooling water, oil system and ballast piping system of many larger vessels. They are especially suited for flow throttling control of heat exchangers in engine room. Measurement by the PIV(Particle Image Velocimetry) was conducted to investigate the flow characteristics of butterfly valve inserted within circular pipe. Flow behaviors such as instantaneous and time-mean velocity vectors are investigated. Furthermore, to reveal systematic performance of the butterfly valve, wall pressure was measured at 6 points along the pipe by digital manometer. As the valve position moves to the closed side, flow separation increases and persists its tendency downstream until smoothly uniform flow developed. The pressure loss is found to be about zero for the disk open angles less than 45 degrees, but is substantially increased for those larger than 60 degrees.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.333-337
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• 2011

Purpose: Various operations have been proposed to compensate for congenital absence of the vagina using ileal or colonic interposition. These methods involve laparotomy, which shows postoperative complications such as long scar and delayed recovery. One case of neovagina reconstruction with laparoscopic rectosigmoid colpopoiesis in Mayer-Rokitansky-Kuster-Hauser syndrome is presented to avoid laparotomic complications. Methods: Laparoscopic surgery was performed in a 27-year-old MRKH syndrome patient. After a cruciate incision, blunt dissection through two-finger wide space was created between the bladder and the rectum. A 14-cm rectosigmoid segment vascularized by a branch of sigmoid artery was isolated by laparoscopy. The distal end was sutured with vaginal vestibule mucosa. A continuity of intestine was restored by circular end-to-end proximate curved intraluminal stapler CDH29$^{(R)}$ through perineal opening. Results: Total operation time was 4 hr 15 min. Normal walking and ingestion were possible within 3 days and 4 days after surgery. The hospital stay was 7 days and the patient was followed up for 6 months. The neovaginal introitus was wide enough for inserting two fingers, and there has been no narrowing of the neovagina on palpation as confirmed by vaginogram. The patient had functional self-lubricating neovagina without excessive mucous production or the need for routine dilation or unnoticeable scar. Conclusion: The successful result of this laparoscopic vaginal reconstruction technique with rectosigmoid segment suggests that this technique can be considered for the option of vaginal reconstruction in girls with the MRKH syndrome.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.108-114
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• 2006

Transient and asymmetric density distributions of butane flow have been investigated from laser image signals by developed three-dimensional digital speckle tomography. Moved signals of speckles have been captured by multiple CCD images in three angles of view simultaneously because the flows were asymmetric and transient. The signals of speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays fur density gradients. The three-dimensional density fields have been reconstructed from the fringe shift signal which is integrated from the deflection angle by a real-time multiplicative algebraic reconstruction technique (MART).

• Computational Structural Engineering
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• v.4 no.4
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• pp.79-89
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• 1991

New design method of R/C slab system based on finite element method has been presented. The proposed method can substitute inaccurate existing method, which has limitation in its application, and provide accurate and efficient design results for any type of slab system. Isoparametric plate element used in the slab design has been efficiently formulated to save computational time. Reinforcement has been determined by strength design method and compared with code minimum values. Graphical output through comprehensive contour map for resulting moments and designed steel areas has considerably facilitated design process. Accurate shear results from isoparametric plate element enabled to check punching shear in a proper manner. In addition to strength design criteria, serviceability has also been checked by utilizing newly developed inelastic deflection multiplier method. An example for circular slab with opening showed that the proposed method could be applied to design of irregular slab without any difficulty.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.107-113
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• 1993

Small rectangular explosion chamber of its size 25cmX25cmX32cm with a circular bursting diaphram at the top was used to study the mechanism of gas explosion to fire transition phenomena, the process of ignition of solid combustibles during a gas explosion. To visulize the explosion to fire transition phenomena, transparent acryl window and high speed camera system were used. The test piece of solid combustible in this experiments was a 5cm$\times$5cm square sheet of newspaper which was placed in the explosion chamber filled with a LPG-air mixture. The mixture was ignited by an electric spark at the center of the chamber. Explosion to fire transition phenomena and the behavior of out flow and in flow of gas through the opening yielded by bursting the diaphram was visualized with shlieren system and without shlieren system. Diameter of a bursting dlaphram at the top of the explosion chamber was varied 5cm, 10cm, and 15cm, and the position of test piece were varied with 6 point. Explosion pressure was measured with strain type pressure transducer, and the weight difference of the test piece before and after each experimental run was measured. By comparing the weight difference of solid combustibles before and after the experiment and the behavior of out flow and inflow of gas after explosion, it was found that the possibility of ignition was depends on the LPG-air mixture concentration and the exposure period of test piece to the burnt gas. Test result of this experiments it was found that the main factor of this phenomena are that heat transfer to the test piece, and the pyrolysis reaction of test piece. Based on the results, the mechanism of the explosion to fire transition phenomena were inferred ; gas explosion- heat transfer to solid combustibiles ; pyrolysis reaction of solid combutibles : air inflow ; mixing of the pyroly gas with air ignition.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.4
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• pp.361-372
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• 2019

The flow pattern of air layers and skin-friction drag reduction by air injection are investigated to find the suitable multiphase flow model using unstructured finite-volume CFD solver for the Reynolds-averaged Navier-Stokes equations. In the present computations, two different multiphase flow modeling approaches, such as the Volume of Fluid (VOF) and the Eulerian Multi-Phase (EMP), are adopted to investigate their performances in resolving the two-phase flow pattern and in estimating the frictional drag reduction. First of all, the formation pattern of air layers generated by air injection through a circular opening on the bottom of a flat plate are investigated. These results are then compared with those of MMkiharju's experimental results. Subsequently, the quantitative ratios of skin-friction drag reduction including the behavior of air layers, within turbulent boundary layers in large scale and at high Reynolds number conditions, are investigated under the same conditions as the model test that has been conducted in the US Navy's William B. Morgan Large Cavitation Channel (LCC). From these results, it is found that both VOF and EMP models have similar capability and accuracy in capturing the topology of ventilated air cavities so called'air pockets and branches'. However, EMP model is more favorable in predicting quantitatively the percentage of frictional drag reduction by air injection.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.327-351
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• 2009

Laboratory tests are performed in this paper to investigate the brittle failure characteristics of over-stressed rocks taken in deep depth. Also, numerical simulation performed using that the so-called CWFS(Cohesion Weakening Frictional Strengthening) model is known to predict brittle failure phenomenon reasonably well. The most typical rock types of Korean peninsula - granite and gneiss - were used for testing. Results of uniaxial compression tests showed that the crack initiation stress was about 41 % to 42% of the uniaxial compressive strength regardless of rock types, where as, the crack damage stress of granite was about 75%, and that of gneiss was about 97%. Through the damage-controlled test, strength parameters of each rock were obtained as a function of damage degree. After the peak, the crack damage stress and the maximum stress were decreased, The cohesion was decreased and the friction angle was increased with increase of rock damage. Before reaching the peak, the elastic modulus was slightly increased, while decreased after the peak. Poisson's ratio was increased as the damage of rock proceeds. Comparison of uniaxial compression tests and damage-controlled tests shows the crack initiation stress estimated from the damage-controlled test fluctuated within the range of crack initiation stress obtained from the uniaxial compression test; the crack damage stress was less than that estimated from the uniaxial compression test. In order to predict the critical depth that brittle failure occurs, numerical simulations using the CWFS model were performed for an example site. Material parameters obtained from the laboratory tests mentioned above were used for CWFS simulation. Comparison between the critical depth predicted from the numerical simulation using the CWFS model and that predicted by using the damage index proposed by Martin et al.(l999), showed that critical depth cannot be reasonably predicted by the currently used damage index except for circular tunnels. A modified damage index was proposed by the author which takes the shape of tunnels other than circular into account.

• The Journal of the Petrological Society of Korea
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• v.10 no.2
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• pp.121-131
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• 2001

The combination of geological, structural and satellite image studies is used to make an examination of the Miocene eruptive type in the Eoil Basin, SE Korea. The basin subsided by the NW-SE extension due to NNW dextral shearing during the East Sea opening. Based on geological structures as well as lithofacies and ages of the basin-fills, it is divided into the NE subbasin and the SW subbasin which were abundantly filled with basaltic volcanics and marine sediments without volcanic materials, respectively: Syndeposional synclines and anticlines are characteristically developed in the NE subbasin, which amplitudes decrease away from the adjacent normal faults to make them into a homoclinal structure. The thicker lavas as well as the younger agglomerates and lacustrine sediments, which show circular distributions, are distributed around the axial zones of major synclines. The satellite image shows four remarkable circular structures within the NE subbasin. They are located adjacent to and along the normal faults, and they are laid almost exactly on the axial zones of the synclines as well as on the distribution area of the agglomerates and lacustrine sediments. These facts indicate that the basaltic lava effusion were conducted by the normal faults like a kind of fissure-eruption and its activity was more predominant at the sites in where the synclines are developed. More active effusion of lava became a reason for deeper subsidence to make differential subsidence and syndepositional folding adjacent to and along the normal faults. Hence, we suggest that a nested cauldron structure was formed in the NE subbasin of the Eoil Basin, and that the volcanism made the subbasin to be a lava pond and controlled the process of filling and sedimentation in the subbasin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.201-207
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• 1979

The stow net now used in the Yellow Sea, are traditional bag net with the opening held by a lighter upper and a weighted lower beams standing against the current. Such bag net anchored at the bottom are known in many countries, particularly in the estuaries of large rivers, but more rarely in sea fisheries, because they are too much affected by the weather, moreover a permanent strong current is necessary. Some scientists intended to improve this fishing gear, using the shearing devices instead of a lighter upper and a weighted lower beams in order to widen mouth of the stow net however they are unsuccessful. One-fortieth scale model net of the stow net was tested in a circular water tank with an effective volume of $5.67m\times1.76m\times1.00m$ of observing the configuration and tension of the net. Experiments were carried out under the various combination including water velocity, spherical floats and elevating floats with the shearing hoods instead of the upper beam. We found those devices offered a very low resistance per net area to current compared with the spherical floats or upper beam, and had a fairly good shearing power at any velocity and direction of the current. The total resistance (R) of the model net to which shearing hoods and floats are attached can be induced by the following formula under the condition of 0.25m/sec to 0.5m/sec, $$R(kg)=3.11V^{1.54}$$ The height (h) of the improved model net (m-B) is higher than traditional model net(m-A) with upper and lower beams, m-A: h(cm)=89.22-2.42(V-15). $V\geqq15,\;cm/sec$ m-B: h(cm)=89.20-0.78V (V:cm/sec) The catch efficiency of improved model net is 1.5 times traditional model net.

• Journal of Venture Innovation
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• v.5 no.1
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• pp.107-127
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• 2022

Global challenges such as the corona pandemic, climate change and the war-on-tech ensure that the demand who the technologies of the future develops and monitors prominently for will be on the agenda. Development of, and applications in, agrifood, biotech, high-tech, medtech, quantum, AI and photonics are the basis of the future earning capacity of the Netherlands and contribute to solving societal challenges, close to home and worldwide. To be like the Netherlands and Europe a strategic position in the to obtain knowledge and innovation chain, and with it our autonomy in relation to from China and the United States insurance, clear choices are needed. Brainport Eindhoven: Building on Philips' knowledge base, there is create an innovative ecosystem where more than 7,000 companies in the High-tech Systems & Materials (HTSM) collaborate on new technologies, future earning potential and international value chains. Nearly 20,000 private R&D employees work in 5 regional high-end campuses and for companies such as ASML, NXP, DAF, Prodrive Technologies, Lightyear and many others. Brainport Eindhoven has a internationally leading position in the field of system engineering, semicon, micro and nanoelectronics, AI, integrated photonics and additive manufacturing. What is being developed in Brainport leads to the growth of the manufacturing industry far beyond the region thanks to chain cooperation between large companies and SMEs. South-Holland: The South Holland ecosystem includes companies as KPN, Shell, DSM and Janssen Pharmaceutical, large and innovative SMEs and leading educational and knowledge institutions that have more than Invest €3.3 billion in R&D. Bearing Cores are formed by the top campuses of Leiden and Delft, good for more than 40,000 innovative jobs, the port-industrial complex (logistics & energy), the manufacturing industry cluster on maritime and aerospace and the horticultural cluster in the Westland. South Holland trains thematically key technologies such as biotech, quantum technology and AI. Twente: The green, technological top region of Twente has a long tradition of collaboration in triple helix bandage. Technological innovations from Twente offer worldwide solutions for the large social issues. Work is in progress to key technologies such as AI, photonics, robotics and nanotechnology. New technology is applied in sectors such as medtech, the manufacturing industry, agriculture and circular value chains, such as textiles and construction. Being for Twente start-ups and SMEs of great importance to the jobs of tomorrow. Connect these companies technology from Twente with knowledge regions and OEMs, at home and abroad. Wageningen in FoodValley: Wageningen Campus is a global agri-food magnet for startups and corporates by the national accelerator StartLife and student incubator StartHub. FoodvalleyNL also connects with an ambitious 2030 programme, the versatile ecosystem regional, national and international - including through the WEF European food innovation hub. The campus offers guests and the 3,000 private R&D put in an interesting programming science, innovation and social dialogue around the challenges in agro production, food processing, biobased/circular, climate and biodiversity. The Netherlands succeeded in industrializing in logistics countries, but it is striving for sustainable growth by creating an innovative ecosystem through a regional industry-academic research model. In particular, the Brainport Cluster, centered on the high-tech industry, pursues regional innovation and is opening a new horizon for existing industry-academic models. Brainport is a state-of-the-art forward base that leads the innovation ecosystem of Dutch manufacturing. The history of ports in the Netherlands is transforming from a logistics-oriented port symbolized by Rotterdam into a "port of digital knowledge" centered on Brainport. On the basis of this, it can be seen that the industry-academic cluster model linking the central government's vision to create an innovative ecosystem and the specialized industry in the region serves as the biggest stepping stone. The Netherlands' innovation policy is expected to be more faithful to its role as Europe's "digital gateway" through regional development centered on the innovation cluster ecosystem and investment in job creation and new industries.