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Amphibians and fish show considerable regeneration potential via dedifferentiation of somatic cells into blastemal cells. In terms of dedifferentiation, in vitro cellular reprogramming has been proposed to share common processes with in vivo tissue regeneration, although the details are elusive. Here, we identified the cytoskeletal linker protein desmoplakin (Dsp) as a common factor mediating both reprogramming and regeneration. Our analysis revealed that Dsp expression is elevated in distinct intermediate cells during in vitro reprogramming. Knockdown ofDspimpedes in vitro reprogramming into induced pluripotent stem cells and induced neural stem/progenitor cells as well as in vivo regeneration of zebrafish fins. Notably, reducedDspexpression impairs formation of the intermediate cells during cellular reprogramming and tissue regeneration. These findings suggest that there is a Dsp-mediated evolutionary link between cellular reprogramming in mammals and tissue regeneration in lower vertebrates and that the intermediate cells may provide alternative approaches for mammalian regenerative therapy.

This paper proposes designs for blades and a water velocity amplification device for the development of a 5-kW duct-type floating tidal current turbine. In addition, it verifies the power performance by a CFD simulation. A BEM theory-based algorithm is used for iterative design and analysis to delay the onset of the chronic problem of cavitation in tidal current turbine blades. The HEEDS optimization software connected to CAE tools is applied to optimize the design of the duct shape, thereby improving the efficiency of the tidal current turbine. The performance of the designed turbine is verified using the CFD software STAR CCM+. A wave model is established to reflect the pressure variation in shallow water when analyzing the cavitation and power performance. The power and efficiency at the rated water velocity are 5 kW and 44 %, respectively. The results indicate that power can be stably controlled due to stalling under the high-flow-velocity condition.

Sub-micron pixels have been widely adopted in recent CMOS image sensors to implement high resolution cameras in small form factors, i.e. slim mobile-phones. Even with shrinking pixels, customers demand higher image quality, and the pixel performance must remain comparable to that of the previous generations. Conventionally, to suppress the optical crosstalk between pixels, a metal grid has been used as an isolation structure between adjacent color filters. However, as the pixel size continues to shrink to the sub-micron regime, an optical loss increases because the focal spot size of the pixel’s microlens does not downscale accordingly with the decreasing pixel size due to the diffraction limit: the light absorption inevitably occurs in the metal grid. For the first time, we have demonstrated a new lossless, dielectric-only grid scheme. The result shows 29 % increase in sensitivity and +1.2-dB enhancement in Y-SNR when compared to the previous hybrid metal-and-dielectric grid.

We developed a dual pixel with accurate and all-directional auto focus (AF) performance in CMOS image sensor (CIS). The optimized in-pixel deep trench isolation (DTI) provided accurate AF data and good image quality in the entire image area and over whole visible wavelength range. Furthermore, the horizontal-vertical (HV) dual pixel with the slanted in-pixel DTI enabled the acquisition of all-directional AF information by the conventional dual pixel readout method. These technologies were demonstrated in 1.4μm dual pixel and will be applied to the further shrunken pixels.

South Korea's new energy transition policy was declared in 2017 as citizen demand grew for solutions to safety problems caused by successive earthquakes affecting areas with many nuclear power plants in 2016 and 2017 as well as health problems caused by coal-fired power plants contributing to high condensable particulate matter in spring. This policy focuses on both a reduction in nuclear and coal-fired power plants and further development of eco-friendly and sustainable power generation and supply. The South Korean government is thus planning a large-scale transition toward improved energy efficiency as well as safe and clean energy sources. Its announced goal is to supply a 20% share of renewable energy in the national energy mix, including 37 GW of photovoltaic power, 3 GW of onshore wind power, and 13 GW of offshore wind power by 2030; the latter is expected to play a strategic role in the Renewable Energy 2030 plan. As South Korea's geographic conditions enable large-scale offshore wind farm projects that are relatively free from complaints and visual effects caused by transportation, installation, noise, vibration, and damage to natural environments, it is highly likely that wind power will become one of the nation's major renewable electricity sources. This paper discusses the potential for developing offshore wind farm projects in South Korea with particular focus on analyzing offshore resources and reviewing government policies and support programs that could limit or otherwise challenge the deployment of such projects, with further considerations of policy choices that could improve the deployment of offshore wind power. As the greatest hindrances to offshore wind power development are frequently-changed government policies and support programs, the adoption of consistent, stable, and efficient guidelines and supports would be most beneficial for meeting South Korea's goals of increased offshore wind energy supplies.

The physical characteristics of a wind field significantly influence the energy produced by a wind farm because they are related to the available kinetic energy in the wake region created by wind turbine generators; they also affect wake recovery. To understand the correlation between the external environment and the amount of energy produced, a study based on the interaction between the power characteristics of wind turbines and atmospheric factors is required. In this study, the distribution characteristics of the turbulence dissipation rate (e) with the regime were analyzed after classifying atmospheric stability by regimes. In addition, the normalized power of wind turbines was analyzed, and the difference in annual energy production (AEP) with the regime was presented. The AEP showed the best value in the slightly unstable regime and the lowest value in the stable regime. Finally, considering the annual mean wind speed at the study site, a difference of approximately 5%–7% was observed between the AEP under the neutral atmospheric regime and other atmospheric regimes. Further, this study highlights the impact of atmospheric stability regimes and the turbulence dissipation rate on energy production, thereby indicating the necessity of integrating these factors to predict the AEP of wind farms.

A 0.8 μm-pitch 64 megapixels ultrahighresolution CMOS image sensor has been demonstrated for mobile applications for the first time. Full-well capacity (FWC) of 6k e- was achieved in 0.8 μm pixels as the best in the world, and the advanced color filter (CF) isolation technology was introduced to overcome sensitivity degradation. Dual conversion gain (CG) technology was also first applied to mobile applications to improve the FWC performance of Tetracell up to 12k e-. In addition, highly refined deep trench isolation (DTI) and photodiode design significantly improved dark noise characteristics.

Contamination and erosion at the leading edge of blade tips adversely affect the annual energy production (AEP) of wind turbines. Obtaining pertinent quantitative data would help in the efficient planning of operations and maintenance of these turbines. In this study, to quantitatively analyze the effects of contamination and erosion on the aerodynamic performance of a blade tip airfoil (NACA 64-618) and in turn on the AEP loss of wind turbines, transient computational fluid dynamics simulations and AEP calculations were performed for a 5-MW National Renewable Energy Laboratory wind turbine. The simulations indicated that depending on the severity of the conditions, contamination and erosion conditions reduced and increased the lift and drag coefficients, respectively, of the blade by up to 53% and 314%. Contamination and erosion conditions reduced AEP by 2%–3.7%.

The blade design of a horizontal axis wind turbine (HAWT) prioritizes structural stability over aerodynamic performance, which results in power loss caused by stalling in the inboard regions. In this study, a vortex generator (VG) was employed for stall control. Because the generated vortex intensity varies with the VG geometry and size, design values based on the aerodynamic characteristics of airfoils in a wind turbine blade were considered. The VG design values for the HAWT were determined based on the computational fluid dynamics (CFD) analysis of the airfoil in the blade region with the maximum chord length. VG applicability was examined for all airfoils applied to the blade inboard region. Based on the lift and drag data obtained through the CFD analysis, the performance improvement of the wind turbine was analyzed through the blade element momentum theory. This analysis also incorporated the angle of attack of the airfoil, which differed for each local cross section in a wind turbine. The VG application increased the wind turbine power for each wind speed interval by an average of 2.5% and the annual energy production by up to 2.7%. The application of the proposed VG design to the inboard region can control the radial flow generated near the hub, improving the aerodynamic performance and decreasing the power loss.

This study proposes a new formula for estimating the uncertainty in pitch-controlled wind turbines regardless of the type of wind turbines or the availability of measurement data. The results obtained using a manufacturer's power curve (MPC), which is defined as the representative value of the power performance of wind turbines, may differ from the prediction results of power generation obtained using an actual power curve measured at a real wind farm. Therefore, the uncertainty of the MPC can considerably influence the calculation of power generation. However, the current methods used for uncertainty calculation either use a random constant chosen by the judgment of individual analyzers based on their experience or rely on a limited set of empirical formulas suggested through the analysis of data measured from specific wind turbines. To solve this problem, we suggest a new formula for uncertainty estimation that has general applicability. The suggested formula was validated by comparing its results with the data output measured from a real wind farm. In addition, a comparison of the real-time estimation results of wind power generation and measurement results demonstrates that the proposed formula produces more reliable results than the existing formula.

A downstream wind turbine located within the reach of the wake region of an upstream wind turbine experiences a decrease in power output due to wake effects. For this reason, when designing a wind farm, various engineering wake models are used to predict the power deficit and wind farm layout is designed in the optimal way to minimize the wake losses. Generally, in the process of calculating the loss of wind farm AEP, in most cases the single point-measured wind speed is used. However, this results in an error when predicting the loss of AEP under wake conditions. When predicting the AEP of a wind turbines affected by wakes, the rotor equivalent wind speed (REWS), which considers the effect of wake wind shear, should be applied. This research examined REWS power converted from the power output of a wind turbine to demonstrate the need of rotor equivalent wind speed under upstream turbine's wake condition and furthermore suggested a method to calculate REWS spws using the nacelle-measured wind speed. By analyzing 48 months collected data of Supervisory Control and Data Acquisition (SCADA) system from a wind farm, error percentages among REWS power , REWS spws , and the nacelle-measured wind speed were compared.

BACKGROUND: Pasteurized autograft is regarded as a biologic reconstructive option for managing bone defects after tumor resection; however, reports on long-term outcomes from large patient series are scarce. Contrary to previous favorable reports, we have observed many patients with failures, in particular as the duration of followup increased. Because pasteurized autografts are used in many countries as a reconstruction option, we wished to formally evaluate patients who underwent this approach at one specialty center. QUESTIONS/PURPOSES: (1) What is the graft survival and what proportion of patients achieved union when pasteurized autografts were used for bone defects after tumor resection? (2) What are the complications and causes of graft removal? (3) What factors are related to the likelihood of union and graft survival? (4) What is the survival and cause of failure by type of pasteurized autograft reconstruction? METHODS: Over a 26-year period from 1988 to 2013, we performed 1358 tumor resections in our center. Of these, 353 were reconstructed with pasteurized autograft. Other reconstructions included endoprostheses (508 patients), instant arthrodesis using an intramedullary nail and bone cement (286 patients), allografts (97 patients), and resection only (114 patients). During the period in question, we generally used this approach when tumor showed an osteoblastic pattern and less than one-third cortical destruction in osteolytic tumor. We generally avoided this approach when the tumor showed an extensive osteolytic pattern. We excluded 75 (21% [75 of 353]) patients, 21 (6% [21 of 353]) for incomplete clinical data and 54 (15% [54 of 353]) with a followup < 2 years or those lost to followup leaving 278 autografts eligible. The mean followup was 113 months (range, 25–295 months). Of these 278 patients, 242 patients had primary bone sarcomas, 22 patients had soft tissue tumor invading bone, seven patients had metastatic carcinoma, and seven patients had aggressive benign bone tumors. From a chart review, we obtained the age, sex, location, tumor volume, histologic diagnosis, use of chemotherapy, graft length, fixation modality, type of pasteurized bone used, proportion of union, complications, and oncologic outcome of the patients. In total, 377 junctional sites were assessed for union with serial radiographs. We defined junctions showing union < 2 years as union and > 2 years as delayed union. We grouped our patients into type of pasteurized bone use: pasteurized autograft-prosthesis composites (PPCs) were performed in 149, intercalary grafts in 71, hemicortical grafts in 15, osteoarticular in 12, and fusion of a joint in 31 patients. The endpoint of interest included removal of the autograft with implant loosening, infection, fracture of the graft, or any reoperation resulting in removal. Survival of the graft was determined by Kaplan-Meier plot and intergroup differences were determined using log-rank test. RESULTS: Five, 10-, and 20-year survival of 278 autografts was 73% ± 5.5%, 59% ± 6.7%, and 40% ± 13.6%, respectively. Of 278 autografts, 105 (38%) were removed with complications. Cause of removal included infection in 13% (33 patients), nonunion in 7% (18 patients), fracture of graft in 6% (16 patients), resorption of the graft in 5% (14 patients), and local recurrence in 4% (11 patients). Univariate survival analysis revealed that patient age ≤ 15 years (p = 0.027; hazard ratio [HR], 1.541), male sex (p = 0.004; HR, 1.810), and pelvic location (p = 0.05; HR, 2.518) were associated with graft removal. The 20-year survival rate of osteoarticular and hemicortical methods was 92% (95% confidence interval, -15.6% to +8.3%) and 80% ± 20%, respectively. For intercalary and fusion, it was 46% ± 15% and 28% ± 22%, respectively, although for PPC, it was 37% ± 22%. Log-rank survival analysis showed the osteoarticular and hemicortical groups had better graft survival compared with other types of reconstruction (p = 0.028; HR, 0.499). The most prevalent cause of graft removal in three major types of reconstruction was as follows: (1) PPC type was infection (30% [17 of 56]); (2) intercalary graft was infection, nonunion, and local recurrence in even proportions of 29% (86% [24 of 28]); and (3) fusion was infection (35% [six of 17]). Two hundred ten (56%) of 377 junctional sites showed union within 2 years (average, 14 months), 51 (13%) junctions showed delayed union after 2 years (average, 40 months), and the remaining 116 (31%) junctions showed nonunion. Diaphyseal junction (p = 0.029) and male sex (p = 0.004) showed a higher proportion of nonunion by univariate analysis. CONCLUSIONS: Compared with the favorable short-term and small cohort reports, survival of pasteurized autograft in this long-term large cohort was disappointing. We believe that pasteurized autograft should be used with caution in children and adolescents, in the pelvic region, and in PPC form. When bone stock destruction is minimal, it is worth considering this approach for small intercalary or distal long bone reconstruction. We believe this procedure is best indicated after hemicortical resection of long bone. LEVEL OF EVIDENCE: Level III, therapeutic study.

Accurate prediction of the time-dependent system dynamic responses of floating offshore wind turbines (FOWTs) under aero-hydro-coupled conditions is a challenge. This paper presents a numerical modeling tool using commercial computational fluid dynamics software, STAR-CCM+(V12.02.010), to perform a fully coupled dynamic analysis of the DeepCwind semi-submersible floating platform with the National Renewable Engineering Lab (NREL) 5-MW baseline wind turbine model under combined wind&ndash, wave excitation environment conditions. Free-decay tests for rigid-body degrees of freedom (DOF) in still water and hydrodynamic tests for a regular wave are performed to validate the numerical model by inputting gross system parameters supported in the Offshore Code Comparison, Collaboration, Continued, with Correlations (OC5) project. A full-configuration FOWT simulation, with the simultaneous motion of the rotating blade due to 6-DOF platform dynamics, was performed. A relatively heavy load on the hub and blade was observed for the FOWT compared with the onshore wind turbine, leading to a 7.8% increase in the thrust curve, a 10% decrease in the power curve was also observed for the floating-type turbines, which could be attributed to the smaller project area and relative wind speed required for the rotor to receive wind power when the platform pitches. Finally, the tower-blade interference effects, blade-tip vortices, turbulent wakes, and shedding vortices in the fluid domain with relatively complex unsteady flow conditions were observed and investigated in detail.

The root region of small wind turbines experience low Reynolds number (Re) flow that makes it difficult to design airfoils that provide good aerodynamic performance and at the same time, provide structural strength. In the present work, a multi-objective genetic algorithm code was used to design airfoils that are suitable for the root region of small wind turbines. A composite Bezier curve with two Bezier segments and 16 control points (11 of them controlled) was used to parametrize the airfoil problem. Geometric constraints including suitable curvature conditions were enforced to maintain the airfoil thickness between 18% and 22% of chord and a trailing edge thickness of 3% of chord. The objectives were to maximize the lift-to-drag ratio for both clean and soiled conditions. Optimization was done by coupling the flow solver to a genetic algorithm code written in C++, at Re = 200,000 and for angles of attack of 4 and 10 degrees, as the algorithm was found to give smooth variation of lift-to-drag ratio within such a range. The best airfoil from the results was tested in the wind tunnel as well as using ANSYS-CFX. The experimental airfoil had a chord length of 75 mm and was provided with 33 pressure taps. Testing was done for both free and forced transition cases. The airfoil gave the highest lift-to-drag ratio at an angle of 6 degrees with the ratio varying very little between 4 degrees and 8 degrees. Forced transition at 8% of chord did not show significant change in the performance indicating that the airfoil will perform well even in soiled condition. Fixed trailing edge flaps (Gurney flaps) were provided right at the trailing edge on the lower surface. The lift and drag behavior of the airfoil was then studied with Gurney Flaps of 2% and 3% heights, as it was found from previous studies that flap heights of 1% or greater than 3% do not give optimum results. The flaps considerably improved the suction on the upper surface and also improved the pressure on the lower surface, resulting in a higher lift coefficient; at the same time, there was also an increase in the drag coefficient but it was less compared to the increase in the lift coefficient. The results indicate that Gurney flaps can be effectively used to improve the performance of thick trailing edge airfoils designed for the root region of small wind turbines.

The power generation of wind turbines varies depending on external environmental conditions. To present universal correlations between conditions that affect wind speed and wind turbine power, this study analyzed the effects of three atmospheric factors—atmospheric stability, turbulence intensity (TI), and wind shear exponent (WSE)—on the power performance and annual energy production (AEP) of wind turbines. Additionally, the horizontal and vertical speed components of the 3D sonic anemometer were investigated. At two measurement heights, unstable regimes showed an ascending air current, whereas stable regimes simultaneously showed both ascending and descending currents. Power curves calculated for each atmospheric factor regime revealed that atmospheric stability (200 kW–11 m/s) exhibited the greatest difference, followed by TI (91 kW–11 m/s) and WSE (32 kW–10.5 m/s). Finally, AEP was calculated at the annual mean wind speed of the study site and exhibited variations of 1.4–4% according to the factor regime. The AEP difference due to the change in atmospheric stability was greatest, and AEP was highest in moderately unstable atmospheric conditions. Clearer understanding of the effects of atmospheric factors on the power characteristics and AEP of wind turbines is expected to deliver practical benefits for wind-resource assessment and power-production prediction.

A Wind resource assessment and optimal micrositing of wind turbines were implemented for the development of an onshore wind farm of 30 MW capacity on Gadeok Island in Busan, Republic of Korea. The wind data measured by the automatic weather system (AWS) that was installed and operated in the candidate area were used, and a reliability investigation was conducted through a data quality check. The AWS data were measured for one year, and were corrected for the long term of 30 years by using the modern era retrospective analysis for research and application (MERRA) reanalysis data and a measure- correlate-predict (MCP) technique; the corrected data were used for the optimal micrositing of the wind turbines. The micrositing of the 3 MW wind turbines was conducted under 25 conditions, then the best-optimized layout was analyzed with a various wake model. When the optimization was complete, the estimated park efficiency and capacity factor were from 97.6 to 98.7 and from 37.9 to 38.3, respectively. Furthermore, the annual energy production (AEP), including wake losses, was estimated to be from 99,598.4 MWh to 100,732.9 MWh, and the area was confirmed as a highly economical location for development of a wind farm.

Detailed feasibility studies are necessary for wind farm development projects because the profitability changes greatly according to wind resource, wind turbine, CAPEX (capital expenduture), OPEX (operation expenditure), SMP (system marginal price), and REC (renewable energy certificate) price. Although measuring wind data over one year in the proposed site is essential, it is a cost-intensive and time-consuming process; hence, in the early stages of development, pre-feasibility studies are conducted using reference wind data from the neighboring areas. In the present study, a pre-feasibility study was conducted in Yulchon district of South Korea to develop a 30-MW wind farm. A wind resource map of Yulchon district was predicted using the AMOS (Aerodome Meteorological Observation System) wind data measured at Yeosu Airport. Three cases of wind farms each with different wind turbines were designed, and comparative economic analysis was carried out. The wind farm designed with SL3000/113 wind turbine recorded the highest profitability with project NPV of 33.62 billion KRW(33.29 million USD, 24.33 million EUR) and project IRR of 9.81%.

Wind turbines installed in a wind farm can be affected by wake from neighboring wind turbines, which reduces power production and shortens turbine life due to mechanical fatigue. Therefore, careful consideration of the wake effects is necessary before establishing an optimum layout design for wind farms. Until now, various numerical models have been developed and applied to evaluate the wake effects, but comparison among (and verification of) the measurement results conducted at numerous wind farms have been few and insufficient. To verify the prediction accuracy of engineering wake models, namely, eddy viscosity, Larsen, Jensen, and Frandsen models, which are widely used in wind energy business, the current study presents the results of the comparative analysis of the values measured at a commercially operated onshore wind farm. The results demonstrate that the Jensen model is the best model in predicting the wake-centered velocity deficit under a specific wind-speed condition, and the eddy viscosity and Larsen models are relatively accurate in predicting the width of the wake and its profile. In conclusion, we need to carefully apply a model for wake-effect assessment based on the spacing between wind turbines because the prediction accuracy of the wake models varies with the downstream distance condition.

Wind turbines installed in external environments are subject to a combination of various environmental and operational conditions during their lifetimes, resulting in varying mechanical loads on each of their components. These loads directly impact the turbine lifetime; therefore, research aimed at reducing the load on each component of the wind turbine is required. In this study, load analysis was performed by applying various load reduction control systems. The effect of the load reduction was verified for each controller through individual simulations. Finally, the design load cases (DLC1.1–DLC8.1) required to evaluate the ultimate and fatigue loads based on the IEC 61400-1 ed.3 international standard were defined, and the loads with respect to a 4 MW wind turbine with and without various load reduction systems were calculated. When applying all load reduction controllers, the turbine blades and the tower experienced ultimate load reductions of 1%–31% and 7%–21.7%, respectively, except the tower's side-to-side bending moment. This moment was observed in the idling condition, which was not affected by the control system; hence, no changes were observed in the load. Fatigue equivalent load reductions were also observed at the blade (3%–8.9%) and tower side-to-side load (4.8%–7.8%). Notably, however, the tower fore-aft fatigue load increased by 10% in most sections. This overall load reduction suggests that turbine components can be fabricated using less material, thereby increasing the wind turbine fatigue lifetime. This result is expected to reduce the levelized cost of energy.

As the demand for the development of onshore wind farms in areas with low wind speeds and large offshore wind farms increases, the size of the wind turbine and its rotor has also increased rapidly. An increase in the rotor diameter implies an increase in the relative wind velocity (with respect to each cross section in the radial direction of the blade) near the tip region of the blade. This in return accelerates the surface damage caused by the erosion of the leading edge, thereby increasing the frequency of maintenance and lowering competitiveness in the cost of energy. In this study, computational fluid dynamics (CFD) analysis was performed to analyze the correlation between the leading-edge erosion damage and output performance of the blade. CFD simulations were performed using a tip airfoil (NACA 64_618) and a full-scale wind turbine (NREL 5 MW) based on the state of erosion of discarded blades considering approximately 12 years of maintenance-free operation. The irregular erosion at the airfoil leading edge results in premature stall phenomena and reduces the aerodynamic efficiency. Thus, the accurate analysis of the flow separation point and flow change is necessary. Therefore, three-dimensional transient CFD analysis was performed to consider the complex flow generated on the blade surface. The erosion at the leading edge reduced the airfoil lift by up to 23% and drag by 100%, reducing the aerodynamic efficiency, which in effect reduced annual energy production by up to 4%.

CMOS image sensors (CIS) have attracted much attention for the emerging mobile market, and the demand of high-resolution image sensors in mobile applications continues to increase [1-3]. For this reason, pixel pitch has been reduced down to 1.0μσι for mass production. Nevertheless, CISs are continuously scaling down to meet the strong demand for higher-resolution images. However, when the pixel size is reduced down to the sub-micron regime (possibly smaller than the diffraction limit), it is very important to consider photo sensitivity and crosstalk, which determine signal-to-noise ratio (SNR). To minimize degradation of photo sensitivity, back-side illumination (BSI), which collects light at the back side, is widely used instead of front-side illumination. In addition to BSI technology, deep-trench isolation (DTI) has emerged as a leading candidate to suppress crosstalk since it physically isolates the pixel. Previous work shows that partial-depth DTI can be applied in a 1.12μm-pitch pixel [4]. Furthermore, full-depth DTI has been demonstrated in a 1.12μm pixel with 24% larger full-well capacity (FWC), 30% smaller YSNR10, 2.0dB higher SNR, and especially for lower crosstalk (12.5%) compared with a conventional one [5]. In this work, a 24-Mpixel CIS with 0.9μσι unit pixels that takes advantage of full-depth DTI is demonstrated.

In this paper, we compare and verify the prediction accuracy and feasibility for wind resources on a wind farm using the Weather Research and Forecasting (WRF) model, which is a numerical weather-prediction model. This model is not only able to simulate local weather phenomena, but also does not require automatic weather station (AWS), satellite, or meteorological mast data. To verify the feasibility of WRF to predict the wind resources required from a wind farm pre-feasibility study, we compare and verify measured wind data and the results predicted by WAsP. To do this, we use the Pyeongdae and Udo sites, which are located on the northeastern part of Jeju island. Together with the measured data, we use the results of annual and monthly mean wind speed, the Weibull distribution, the annual energy production (AEP), and a wind rose. The WRF results are shown to have a higher accuracy than the WAsP results. We therefore confirmed that WRF wind resources can be used in wind farm pre-feasibility studies.

In this study, we conduct power performance and load analyses of two different types of vertical-axis tidal-current turbines using the computational fluid dynamics (CFD) method. To analyze the power output and loads, we perform transient CFD simulations considering the cavitation model using ANSYS CFX. The averaged power output of an H-type rotor was 7.47 kW and 67.6 kW in normal and extreme operating conditions, respectively, which did not satisfy the initial design conditions. However, in the case of the helical-type rotor, the power output under normal and extreme conditions were close to the expected values. The cavitation, which may cause instantaneous power fluctuation, occurred repeatedly at the suction side of the rotors. In order to guarantee a more stable power supply and to prevent fatigue failure, we require a design that minimizes cavitation.

We present a design methodology for horizontal-axis tidal turbine blades based on blade element momentum theory, which has been used for aerodynamic design and power-performance analysis in the wind-energy industry. We design a 2-blade-type 1 MW HATT blade, which consists of a single airfoil (S814), and we present the detailed design parameters in this paper. Tidal turbine blades can experience cavitation problems at the blade-tip region, and this should be seriously considered during the early design stage. We perform computational fluid dynamics (CFD) simulations considering the cavitation model to predict the power performance and to investigate the flow characteristics of the blade. The maximum power coefficient is shown to be about 47 under the condition where TSR

Background We hypothesized that hemiarthroplasty with a synthetic device in skeletally immature patients with osteosarcoma around the knee would be functional due to high adaptability in the pediatric age group, and may decrease the number of surgeries until limb equalization by preserving the nearby physis. Methods We analyzed the outcomes of 25 hemiarthroplasties (12 distal femur, 13 proximal tibia). Average patient age was 11.8 years. We assessed (1) whether hemiarthroplasty could be considered as a viable option and could preserve growth of the nearby physis, and (2) whether these patients could reach the final goal of adult-type tumor prosthesis implantation within a preplanned number of surgeries. Results Three (12%) of 25 hemiarthroplasties showed failure. Average Musculoskeletal Tumor Society functional score of 23 patients was 25.1. Average tibial and femoral shortening for the corresponding reconstruction was 0.3 cm and 0.5 cm, respectively. In terms of number of surgeries for limb equalization, 19 patients (76%) had less, four (16%) had equal, and two (8%) had more surgeries than planned. Conclusions Hemiarthroplasty is a sound option until skeletal maturity, allowing surgeons to choose the appropriate procedure based on the patient's growth status, and may reduce the amount of shortening by preserving nearby physis. J. Surg. Oncol. 2015 111:107–114. © 2015 Wiley Periodicals, Inc.

The food waste that occurs in one year is very high in our country and disposal is expensive. However, disposers for food waste are not used wisely at real life. This is because most of them some kind of problem, for example big volume, complicated construction, high cost, lots of troubles, low energy efficiency and so on. In this study, we propose the new dryer system to decrease drying times by injecting hot air in down the side of the drying bucket. The designed drying bucket has inclined inlet holes down both sides. The inlet holes have variable gradients, we adjust the inlet velocity of the hot air to find a suitable vortex in the drying bucket. We verify the properties of the proposed system though simulation. The results show the proposed dryer system can improve the drying time and save energy for food waste disposal.

We present a CMOS image sensor (CIS) with phase detection auto-focus (PDAF) in all pixels. The size of photodiode (PD) is 0.64μm by 1.28μm, the smallest ever reported and two PDs compose a single pixel. Inter PD isolation was fabricated by deep trench isolation (DTI) process in order to obtain an accurate AF performance. The layout and depth of DTI was optimized in order to eliminate side effects and maximize the performance even at extremely low light condition up to 1lux. In particular the AF performance remains comparable to that of 0.70μm dual PD CIS. By using our unique technology, it seems plausible to scale further down the size of pixels in dual PD CIS without sacrificing AF performance.

10nm 2nd generation BEOL technology is described with an optimized illumination system and multi-patterning lithography. While the optimized illumination system offered a possibility to pattern reduced metal pitches in the preferred orientation, difficulties of T-T and T-S patterning still remained. It was overcome by increasing the number of available multi-patterning colors from 2 to 4. First-ever implementation of LELELELE with tight inter-color misalignment control increased scalability up to 17.1% and was demonstrated with SRAM 128Mb yield.

Rotor blades are important devices that affect the power performance, efficiency of energy conversion, and loading and dynamic stability of wind turbines. Therefore, considering the characteristics of a wind turbine system is important for achieving optimal blade design. When a design is complete, a design evaluation should be performed to verify the structural integrity of the proposed blade in accordance with international standards or guidelines. This paper presents a detailed exposition of the evaluation items and acceptance criteria required for the design certification of wind turbine blades. It also presents design evaluation results for a 2-MW blade (KR40.1b). Analyses of ultimate strength, buckling stability, and tip displacement were performed using FEM, and Miner's rule was applied to evaluate the fatigue life of the blade. The structural integrity of the KR40.1b blade was found to satisfy the design standards.

A rotor blade is an important device that converts kinetic energy of wind into mechanical energy. Rotor blades affect the power performance, energy conversion efficiency, and loading and dynamic stability of wind turbines. Therefore, considering the characteristics of a wind turbine system is important for achieving optimal blade design. This study examined the general blade design procedure for a wind turbine system and aero-structure design results for a 2-MW class wind turbine blade (KR40.1b). As suggested above, a rotor blade cannot be designed independently, because its ultimate and fatigue loads are highly dependent on system operating conditions. Thus, a reference 2-MW wind turbine system was also developed for the system integrated load calculations. All calculations were performed in accordance with IEC 61400-1 and the KR guidelines for wind turbines.

This research presents results of structural designs and evaluations for 3MW Wind Turbine Blade by FEM analysis. After the GFRP model was designed as a baseline model, failure check by Puck’s failure criterion and buckling analysis were accomplished to verify safety of wind turbine blade in the critical design load case. Moreover, applicability of two kinds of carbon spar cap model, was studied by comparing total mass, price and tip deflection to the GFRP model. The results showed that the GFRP model had sufficient structural integrity in the critical design load case, and the carbon spar cap model could be a reasonable solution to reduce weights, tip deflections.

The rotor blade is an important device that converts kinetic energy of wind into mechanical energy. It affects power performance, efficiency of energy conversion, load and dynamic stability of a wind power generation system. This paper presents an aerodynamic design of 3 MW class blade using BEM and confirms that the design satisfies the initial design target by BEM and CFD analysis. To investigate the effects of radial flow at the inboard region, the result of static BEM analysis was compared with the result of CFD analysis. The result of quantitative comparison among thrust force, power coefficient and mechanical power depending on wind speed change is presented. Furthermore, design reference data such as pressure, streamline, torque and thrust force distribution on the blade surface is presented as well.

The purpose of this study is to develop a software for the performance evaluation and blade design of a pitch-controlled HAWT using BEMT(Blade Element Momentum Theory) with Prandtl’s tip loss. The HERACLES V2.0 software consist of three major part ; basic blade design, aerodynamic coefficient mapping and performance calculation including stall or pitch control option. A 1MW wind turbine blade was designed at the rated wind speed(12m/s) composing five different airfoils such as FFA-W-301, DU91-W250, DU93-W-210, NACA 63418 and NACA 63415 from hub to tip. The mechanical power predicted by BEMT at the rated wind speed is about 1.27MW. Also, CFD analysis was performed to confirm the validity of the BEMT results. The comparison results show good agreement about the error of 6.5% in rated mechanical power. †† 1. 서 론 최근에 국제적으로 거론되고 있는 각종 환경관련 국제협약과 기후변화협약에 기초한 교토의정서의 채택으로 인해 환경문제의 심각성에 대한 관심이 상당히 높아지고 있다. 우리 정부도 이러한 상황에 대응하기 위해 신재생에너지에 대한 관심이 급격히 증가하고 있는 실정이며 그 중에서도 풍력에너지의 높은 가능성에 주목하고 있다. 현재 국내 요소설계 기술수준은 풍력발전용 터빈의 핵심요소기술 중의 하나인 로터 블레이드 설계 기술에 대한 명확한 설계기준이 없는 상황이며, 블레이드 설계 및 성능평가를 위해 BEMT 이론 및 다양한 손실 보정 모델을 적용한 Garrad Hassan 사의 GH-Bladed 등과 같은 국외 상용 소프트웨어에 의존하고 있다. 이러한 국내실정을 감안할 때, 국내에서도 블레이드 설계 및 성능평가* 한국해양대학교 해양에너지 전문인력양성사업단** (사)한국선급 에너지ㆍ산업기술센터*** 목포대학교 기계공학과 ****한국해양대학교 기계 ㆍ에너지시스템공학부† 교신저자, E-mail : lyh@hhu.ac.kr에 관한 명확한 기준 등이 수립될 필요가 있으며, 다양한 설계 이론과 성능예측 기법들에 대한 연구를 통해 독자적인 설계 및 성능평가 소프트웨어의 개발이 필요한 시점이다.

This paper examines co-integration and spillover effects between U.S. and Asia-Pacific stock markets using nine Exchange Traded Funds (ETFs) over the period from 7 January 2004 to 30 September 2010, with sub-samples of before and after the 2007–2008 global financial crisis. The nine ETFs include: SPDR, TOPIX, KODEX200 (KODEX), Tracker Fund of Hong Kong (TraHK), Polaris Taiwan Top 50 Tracker Fund (TT), SPDR S&P/ASX 200 Fund (STW), StreetTRACKS Straits Times Index Fund (STI), SmartFONZ (FNZ), and China 50 ETF. The co-integration analysis shows that there is a co-integration relationship between SPDR and TraHK, STW, STI, and FNZ before and after the global financial crisis. However, TOPIX shows little co-integration relationship with SPDR. In the case of KODEX and TT, no co-integration relationship is found before the crisis; however, it is found after the crisis. Before the crisis, SPDR co-integrated with China 50, but after the crisis the co-integration relationship weakened. The Granger causality tests indicate that, although U.S. stock markets lead Asia-Pacific stock markets, Asia-Pacific stock markets do not exert the same influence. GARCH tests show that there are significant spillover effects between the U.S. and Asia-Pacific stock markets. This paper confirms the fact that, since the 2007–2008 global financial crisis, the degree of co-integration and spillover effects has generally grown stronger.

The finite element (FE) method is generally used to model and simulate the physical behavior of large structures, such as passenger vehicles or aircraft. However, FE analysis involves a very large computation time and cost for developing the analysis model. Therefore, the vibration characteristics of large structural systems are often analyzed using the component mode synthesis (CMS) method, which is one of the substructure synthesis methods. In this study, the vibration characteristics of passenger vehicles are analyzed by using the substructure synthesis method. A passenger vehicle model, which includes a vehicle body, suspension systems, and a sub-frame, is presented. The physical components of the vehicle system are modeled as equivalent substructures using the Craig-Bampton method of CMS. The vibration characteristics, such as the natural frequencies and mode shapes and frequency response, of the vehicle system are determined. The effects of variations in some design parameters on the vibration characteristics of the full vehicle model are also investigated.

In cold-region environments characterized by high wind speeds, low external air temperatures, and supercooled water droplets, wind turbines frequently experience ice formation along the leading edge of the blade tip, which has a higher angular velocity. This ice formation directly and negatively affects the wind turbine's power performance. As such, a clear understanding of the relationship between ice formation and wind turbine power performance is required. In this study, we used computational fluid dynamics (CFD) simulation methods based on the dispersed multiphase (DMP) droplet model to predict ice formation along a blade tip airfoil's leading edge. To validate the ice formation model, the CFD simulation results were compared with the previously published wind tunnel testing results. Following validation, the model was used to predict the ice formation along the leading edge of the National Advisory Committee for Aeronautics (NACA) 64-618 airfoil and estimate its aerodynamic performance under variable...

Tuberculous spondylitis is a very rare disease, but it can result in bone destruction, kyphotic deformity, spinal instability, and neurologic complications unless early diagnosis and proper management are done. Because the most common symptom of tuberculous spondylitis is back pain, it can often be misdiagnosed. Atypical tuberculous spondylitis can be presented as a metastatic cancer or a primary vertebral tumor. We must make a differential diagnosis through adequate biopsy. A 30-year-old man visited our clinic due to back and chest pain after a recent traffic accident. About 1 year ago, he had successfully recovered from tuberculous pleurisy after taking anti-tuberculosis medication. We performed epidural and intercostal blocks but the pain was not relieved. For the further evaluation, several imaging and laboratory tests were done. Finally, we confirmed tuberculous spondylitis diagnosis with the biopsy results.