| 1. |
- Lee, J. -H, et al.
(författare)
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Comparative study on added resistance of a bulk carrier in regular head and oblique waves
- 2020
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Ingår i: Proceedings of the International Offshore and Polar Engineering Conference. - : International Society of Offshore and Polar Engineers. - 9781880653845 ; , s. 3385-3393
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Konferensbidrag (refereegranskat)abstract
- In this study, a comparative study on motion response and added resistance of a Supramax bulk carrier (K-Supramax Original) in regular waves was carried out to evaluate the reliabilities and accuracies of experimental and numerical simulation techniques. Two kinds of experiments were performed; one is the towing tank model testing for head wave conditions conducted at Seoul National University, and the other is the free-running model test for head and oblique wave conditions conducted at SSPA Sweden AB. Also, nine numerical computation results submitted by seven institutions were compared with the experimental data. The computation results were obtained by various seakeeping analysis methods such as the 2D strip theory, 3D Rankine panel method, and Computational Fluid Dynamics (CFD) based analysis. Based on the comparison, the characteristics of each numerical technique and resultant accuracies of seakeeping analyses were investigated. It was also confirmed that different results were obtained although the same program was used because of the user dependencies; setting for computation parameters, numerical schemes, and mesh generations, etc. Furthermore, the sensitivities of seakeeping quantities with respect to wave amplitudes were examined by conducting both model tests and nonlinear numerical simulations for different wave slopes. Lastly, the tendencies of ship motion and added resistance depending on the heading angle were identified, and the reliabilities of experiments and numerical computations for oblique waves were discussed.
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| 2. |
- Park, D. -M, et al.
(författare)
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Comparative study on added resistance of a container ship in waves
- 2019
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Ingår i: Proceedings of the International Offshore and Polar Engineering Conference. - : International Society of Offshore and Polar Engineers. - 9781880653852 ; , s. 4418-4425
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Konferensbidrag (refereegranskat)abstract
- This paper presents a comparative study on the motion responses and added resistance of a container ship. Eight institutions participated in the comparative study, and ten numerical results were compared with two experimental results. Two experimental results were obtained from Seoul National University towing tank and Sweden SSPA seakeeping basin. The results of two experimental institutions in head sea condition were compared and showed good agreement with each other. The difference in motion responses and added resistance according to the numerical analysis method were compared. Even though the same program was used, it was observed that different results were obtained depending on the users. The comparison of the motion response and the added resistance according to the change of wave slope showed that the added resistance greatly changed according to the wave slope. This tendency was the same in experimental results and CFD analysis results. From the comparative study, the influence of the experiment method on the added resistance, and the characteristics of numerical each code were identified.
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| 3. |
- Boddaert, S., et al.
(författare)
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Fire safety of BIPV : International mapping of accredited and R&D facilities in the context of codes and standards 2023
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of Task 15 of the IEA Photovoltaic Power Systems Programme is to create an enabling framework to accelerate the penetration of BIPV products in the global market of renewables, resulting in an equal playing field for BIPV products, BAPV products and regular building envelope components, respecting mandatory issues, aesthetic issues, reliability issues, and financial issues.Subtask E of Task 15 is focused on pre-normative international research on BIPV characterisation methods and activity E.3 is dedicated to fire safety of BIPV modules and installations.
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| 4. |
- Kim, Kyung Ho, 1984, et al.
(författare)
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Apparent Power Law Scaling of Variable Range Hopping Conduction in Carbonized Polymer Nanofibers
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- We induce dramatic changes in the structure of conducting polymer nanofibers by carbonization at 800 degrees C and compare charge transport properties between carbonized and pristine nanofibers. Despite the profound structural differences, both types of systems display power law dependence of current with voltage and temperature, and all measurements can be scaled into a single universal curve. We analyze our experimental data in the framework of variable range hopping and argue that this mechanism can explain transport properties of pristine polymer nanofibers as well.
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| 5. |
- Kim, Kyung Ho, 1984, et al.
(författare)
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Probing variable range hopping lengths by magneto conductance in carbonized polymer nanofibers
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Using magneto transport, we probe hopping length scales in the variable range hopping conduction of carbonized polyacetylene and polyaniline nanofibers. In contrast to pristine polyacetylene nanofibers that show vanishing magneto conductance at large electric fields, carbonized polymer nanofibers display a negative magneto conductance that decreases in magnitude but remains finite with respect to the electric field. We show that this behavior of magneto conductance is an indicator of the electric field and temperature dependence of hopping length in the gradual transition from the thermally activated to the activation-less electric field driven variable range hopping transport. This reveals magneto transport as a useful tool to probe hopping lengths in the non-linear hopping regime.
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| 6. |
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| 7. |
- Park, M. S., et al.
(författare)
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InAs/GaAs p-i-p quantum dots-in-a-well infrared photodetectors operating beyond 200 K
- 2014
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Ingår i: Electronics Letters. - Stevenage, United Kingdom : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 50:23, s. 1731-1732
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Tidskriftsartikel (refereegranskat)abstract
- High-temperature operating performance of p-i-p quantum dots-in-awell infrared photodetectors (QDIPs) is successfully demonstrated. The optically active region consists of 10 layers of p-doped selfassembled InAs quantum dots (QDs) asymmetrically positioned in In0.15Ga0.85As quantum wells (QWs). The dark current is suppressed by an incorporated superlattice (SL) structure composed of 10 pairs of AlGaAs/GaAs heterostructure. The very low recorded dark current makes the fabricated p-i-p QDIPs suitable for high-temperature operation. The measured photoresponse reveals broad mid-wave infrared (MWIR) detection up to 200 K.
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| 8. |
- De Jong, Wim H., et al.
(författare)
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Round robin study to evaluate the reconstructed human epidermis (RhE) model as an in vitro skin irritation test for detection of irritant activity in medical device extracts
- 2018
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Ingår i: Toxicology in Vitro. - : Elsevier BV. - 0887-2333 .- 1879-3177. ; 50, s. 439-449
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Tidskriftsartikel (refereegranskat)abstract
- Assessment of skin irritation is an essential component of the safety evaluation of medical devices. OECD Test Guideline 439 describes the use of reconstructed human epidermis (RhE) as an in vitro test system for classification of skin irritation by neat chemicals. An international round robin study was conducted to evaluate the RhE method for determination of skin irritant potential of medical device extracts. Four irritant polymers and three non-irritant controls were obtained or developed that had demonstrated their suitability to act as positive or negative test samples. The RhE tissues (EpiDerm™ and SkinEthic™ RHE) were dosed with 100 μL aliquots of either saline or sesame oil extract. Incubation times were 18 h (EpiDerm™) and 24 h (SkinEthic™ RHE). Cell viability reduction > 50% was indicative of skin irritation. Both the EpiDerm™ and SkinEthic™ RHE tissues were able to correctly identify virtually all of the irritant polymer samples either in the saline, sesame oil or both solvent extracts. Our results indicate that RhE tissue models can detect the presence of strong skin irritants at low levels in dilute medical device polymer extracts. Therefore, these models may be suitable replacements for the rabbit skin irritation test to support the biological evaluation of medical devices.
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| 9. |
- Sheng, Dong Yuan, et al.
(författare)
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Water model study on convection pattern of molten steel flow in continuous casting tundish
- 1998
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Ingår i: ISIJ International. - 0915-1559 .- 1347-5460. ; 38:8, s. 843-851
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Tidskriftsartikel (refereegranskat)abstract
- Natural convection will obviously influence the liquid steel flow in continuous casting (CC) tundish, which cannot be neglected in tundish metallurgical process. Through the theoretical analysis, the dimensionless number, Gr/Re 2, is adopted to determine the convection pattern in tundish system. Validity of this criteria in a reduced scale water model are also discussed in this paper. Non-isothermal water model experiment with the temperature variation of inlet stream, has been simulated to see the effect of temperature variation of ladle stream. The convection pattern of molten steel flow in continuous casting tundish is also studied numerically by using the commercialized computational fluid dynamic (CFD) software package, CFX4. From the results of theoretical analysis, physical and mathematical model simulation, it can be stated that the convection pattern of molten steel flow in tundish is controlled by the combined nature convection and forced convection.
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| 10. |
- Shrestha, Rakesh, et al.
(författare)
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Adaptive software platform architecture for aerial vehicle safety levels in real-world applications
- 2023
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Ingår i: Advances in Computers. - : Academic Press Inc.. - 0065-2458.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Urban cities have congested with vehicles, resulting in traffic jams, and a lot of time and energy will be wasted while traveling. In the near future, low-altitude aerial vehicles are expected to be implemented for air traffic as a resolution to overcome these issues. Due to the threats to commercial aircraft as well as danger to the public and objects on the ground, these low-altitude aerial vehicles should exhibit an equivalent level of safety similar to commercial aircraft. We propose a new safety level for low-altitude electric propeller-based compact aerial vehicles. The safety level of Aerial Vehicles is based on the concept of civil aviation safety levels and automotive safety levels, and we incorporate the appropriate safety characteristics from both automotive safety integrity levels and aviation safety levels. We also discussed adjusting the aerial vehicle safety levels with NASA's Technical Capability Levels (TCL), which helps design an Electrical and Electronics (E/E) architecture for the aerial vehicles. We presented a new conceptual E/E architecture for the aerial vehicles based on adjusted technical capabilities levels and aerial vehicle safety levels to provide functional safety for the aerial vehicle. We also discuss the adaptive software platform based on virtualization, which partitions the time-critical operating system of aerial vehicles to host several applications of different software levels on the same hardware.
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