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Wyszukujesz frazę "Kang, W. H." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Reliability based analysis and design of a tripod offshore wind turbine structure assuring serviceability performance
Autorzy:
Zhang, J.
Kang, W. H.
Zhang, C.
Sun, K.
Powiązania:
https://bibliotekanauki.pl/articles/259493.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
offshore wind turbine
tripod foundation
serviceability limit state
statistical correlation analysis
reliability analysis
Opis:
Typical tripod foundations are designed using deterministic computational models according to relevant standards and codes. However, for more cost-safety balanced design, uncertainties in significant parameters should be considered in preliminary design to ensure meeting a specific probabilistic safety target in the context of the complex configuration of a tripod structure. In this article, uncertainties associated with design parameters and modelling errors are considered using Monte Carlo simulations, in order to determine the key structural design parameters, and to determine the optimal balance between design parameters and design requirements. A Spearman rank-order correlation based analysis is carried out to understand the effects of design variables on maximum deformation, total weight, and natural frequency, and to have insight about important design parameters for improvement of a preliminary design. It is found that the tower diameter has the most significant effect on the maximum displacement on the hub as validated through engineering case studies. In addition, a statistical framework, which identifies influential design parameters and provides reliability evaluation, is proposed for the structural design of a tripod OWT system. The design cases considered in this study indicate that a simple deterministic design check cannot guarantee the required reliability level of the structure, and the cost-safety balance can be achieved by a reliability analysis with the consideration of the uncertainties in the structure.
Źródło:
Polish Maritime Research; 2018, 4; 139-148
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardness prediction of a cold rolled Nimonic 80A exhaust valve spindle
Autorzy:
Kang, S. W.
Heo, S. J.
Yoo, J. H.
Kang, J. H.
Powiązania:
https://bibliotekanauki.pl/articles/367227.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
Nimonic 80A
exhaust valve
stress-strain curve
hardness prediction
finite element method
zawór wylotowy
krzywa naprężenie-odkształcenie
metoda elementów skończonych
Opis:
Purpose: of this paper is to predict the hardness of cold rolled exhausts valve spindle fabricated of Nimonic 80A via axisymmetric finite element analysis, compression testing, and hardness inspection. Design/methodology/approach: The stress-strain relationship of Nimonic 80A was obtained via compression testing with deformation ratios of 10%, 20%, and 30%. Hardness changes caused by the strain hardening effect were measured in cut specimens in both the axial and circumferential directions following compression testing. The effective strain at the measurement position was calculated via finite element analysis. The regression equation for hardness changes caused by work hardening was derived from analysed strain and inspected hardness. The cold-rolling deformation of an exhaust valve spindle was analysed using axisymmetric finite element analysis. Findings: The stress-strain relationship calculated from compression testing was well expressed using the Holloman equation and the strain-hardness relationship by strain hardening was successfully regressed using the shifted power law model for Nimonic 80A, Nickel-Chromium based super alloy. Research limitations/implications: This research focused hardness prediction of spindle after ring rolling operation for generating beneficial compressive surface residual stresses for enhancing fatigue life. Further research to quantify compressive residual stress after rolling shall be followed to increase fatigue life. Practical implications: The cold rolling process is a typical incremental forming method and should be analysed under three-dimensional conditions. However, it takes lots of time to solve incremental forming analysis. To predict hardness distribution after rolling in the manufacturing field, FE analysis was performed under two-dimensional axisymmetric conditions based on the assumption of no friction generated by the rolling tool. The deformed shapes and hardness distribution from the inspection quality standard and two-dimensional FE analysis showed very similar results. Simplified finite element analysis method for ring rolling process for local area could be very effective method in the industrial field. Originality/value: The stress-strain relationship and the hardness and strain relationship were derived by compression test and hardness measurement for compressed specimen for Nimonic 80A, Nickel-Chromium based super alloy. And simplified finite element analysis method was suggested to predict deformed shape and hardness distribution of locally cold rolled region and achieved similar result between FE analysis result and Quality standard. Suggested method would be very effective method to engine spindle manufacture to predict hardness of different size of product.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2019, 94, 1-2; 13-21
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Similarity of chromosome structure among Populus tremula var. davidiana, Populus alba and their hybrids revealed by FISH karyotype analysis
Autorzy:
Kim, Y.G.
Kwon, S.H.
Kang, H.I.
Yoem, D.B.
Kim, K.W.
Kim, H.H.
Kang, K.S.
Powiązania:
https://bibliotekanauki.pl/articles/2077655.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Karyotype analysis
Fluorescence in situ hybridization
Ribosomal DNA site
Poplar
Cytogenetics
Opis:
The genus Populus is one of the important tree species in Korean peninsula and many other coun- tries in the world. It represents the model species of forest genomics because it grows fast and reproduces rapidly. In this reason, their genetic characteristics have been well studied and the whole genome has been sequenced completely in some species. However, cytogenetic study of the genus Populus has been limited. In the present study, karyotypes of Korean aspen (P. tremula var. davidiana), Silver poplar (P. alba) and their two hybrids, Suwon aspen (P. tremula var. glandulosa) and Hyun aspen (P. alba × P. tremula var. glandulsa) were analyzed by means of the fluorescence in situ hybridization (FISH). Root samples were collected from mature trees in the demonstration forest, located at Suwon, Kyonggi province in South Korea. The fresh root cells were examined by DAPI (4’,6-diamidino-2-phenylindole) staining and FISH using 45S rDNA and 5S rDNA probes. As the results, the chromosome compositions of all species were the same as 2n = 38. The karyotype formulas of Korean aspen, Silver poplar, Suwon aspen and Hyun aspen were 28m + 6sm + 4st (2sat), 26m + 10sm (2sat) + 2st, 26m + 12sm (2sat) and 28m + 10sm (2sat), respectively. The four species had one pair of 45S rDNA site and one pair of 5S rDNA site in common with FISH karyotypes. The similarity of FISH karyotypes among four species indicated close genetic relationship and coexistence of their interspecific hybrids. This research will provide genetic information on cytogenetic research of Populus and genetic mapping that can be applied to the breeding program of Populus in the near future.
Źródło:
Dendrobiology; 2020, 83; 68-74
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a shape memory alloy wire actuator to operate a morphing wing
Autorzy:
Rim, M.
Kim, E.-H.
Kang, W.-R.
Lee, I.
Powiązania:
https://bibliotekanauki.pl/articles/280828.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
morphing wing
shape memory alloy (SMA)
wire actuator
Opis:
DSC tests were performed on several types of SMAs to verify the phase-transformation temperatures, and then experiments to examine their characteristics were carried out. An electric-current was supplied to the SMA wire to measure the appropriate operational cur- rent range. The force generated by the SMA wire increased according to the supplied current, but it diminished when the over-current was supplied because thermo-mechanical properties of the wire started to degrade. The appropriate stress range for effective actuation charac- teristics was also investigated. The SMA wire actuator was designed to operate a morphing wing. Experiments for the wing were conducted to verify its characteristics and it was smo- othly deformed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 2; 519-531
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of organic supplementation to reduced rates of chemical fertilization on soil fertility of Zanthoxylum armatum
Autorzy:
Saba, T.
Liu, W.
Wang, J.
Saleem, F.
Kang, X.
Hui, W.
Gong, W.
Li, H.
Powiązania:
https://bibliotekanauki.pl/articles/2130175.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
fertilization
soil fertility
nutrient availability
organic manure
culturable microbes
Opis:
Soil acidification, fertility depletion, food insecurity, and environmental pollution all are consequences of the extensive use of chemical fertilizers (CF) in intensively managed plantations. Recent studies have shown that incorporating organic manure (OM) to partially replace CF can help to maintain productivity and soil health. There are no reports on integrated fertilizer management of Zanthoxylum armatum, for optimal ecological services and economic profitability. A pot experiment with Z. armatum was performed to investigate the possibility of incorporating OM in reducing CF use, enhancing soil fertility, and increasing plant growth. For this, seven treatments were designed: NPK, PK, NP, NK, OM, MNPK (50%NPK+50%OM), and control (CK, no fertilizer application). The results showed that NPK application significantly (P < 0.05) increased plant growth, soil nitrate-N, ammonium-N and available K compared to CK. However conventional CF application induced soil acidification. OM application raised the soil pH from 5.50 (CK) to 6.58 and significantly enhanced soil fertility by increasing alkali-hydrolysable N (2.3 times), ammonium-N (1.4 times), available P (4.3 times), the activity of invertase (1.5 times), catalase (2.8 times), acid phosphatase (1.5 times), and count of soil culturable microbes (2.9 times) compared to CK. Conversely, sole OM application did not result in optimum plant growth. Integrating OM with NPK (MNPK), on the other hand, not only provided the highest growth comprehensive value (0.84), but also substantially higher soil fertility comprehensive value (0.71) than traditional CF treatments. Correlation analysis also indicated a positive and significant correlation between soil microbes, enzyme activities and available nutrients. Therefore, OM+NPK could be an optimum measure to get maximum benefits regarding soil fertility, growth of Z. armatum, fertilizer savings and sustainable agroecology.
Źródło:
Dendrobiology; 2022, 87; 123-136
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differences in gait pattern between the elderly and the young during level walking under low illumination
Autorzy:
Choi, J.-S.
Kang, D.-W.
Shin, Y.-H.
Tack, G.-R.
Powiązania:
https://bibliotekanauki.pl/articles/307026.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gait
illumination
elderly
stance ratio
toe clearance
safety margin
chód
iluminacja
wiek
palec nogi
Opis:
The purpose of this study was to compare changes in the gait pattern between the elderly and young during level (i.e., even surface) walking under low illumination. Vision during walking plays a role in avoiding obstacles and uneven surfaces, as well as an important role in the proactive control of dynamic stability and route planning for level walking. Fourteen elderly and fourteen young male subjects walked on a 7 m walkway with two illumination conditions using self-selected walking speed: walking with normal (>300 lux) and low illumination (<10 lux). Walking speed, stance phase ratio, toe clearance on swing phase, and range of motion at the center of mass were used to compare the differences in gait pattern between two illumination conditions and ages. During walking with low illumination, walking speed and stance phase ratio of the young decreased, and toe clearance of the young increased. However, there was no difference in these variables due to low illumination in the elderly subjects. Despite level walking conditions, there were some differences in gait pattern between the young and the elderly due to illumination conditions. This implies that the young showed a more positive change of gait pattern, due to low illumination, than that of the elderly. In this respect, further study is necessary to identify differences between the young and the elderly, when they walk on an uneven or obstacle walkway with low illumination.
Źródło:
Acta of Bioengineering and Biomechanics; 2014, 16, 1; 3-9
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study On The Metal Carbide Composite Diffusion Bonding For Mechanical Seal
Badanie łączenia dyfuzyjnego kompozytu metal węglik na mechaniczne uszczelnienie
Autorzy:
Kim, D.-K.
Shon, I.-J.
Song, J.
Ryu, W.-J.
Shin, H.-Ch.
Kwon, E.-Y.
Shin, H.
Kang, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/356399.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diffusion bonding
nanostructures
mechanical seal
hard metal
mechanical properties
łączenie
nanostruktura
uszczelnienie mechaniczne
twardy metal
właściwości mechaniczne
Opis:
Mechanical Seal use highly efficient alternative water having a great quantity of an aqueous solution and has an advantage no corrosion brine. Metal Carbide composites have been investigated as potential materials for high temperature structural applications and for application in the processing industry. The existing Mechanical seal material is a highly expensive carbide alloy, and it is difficult to take a price advantage. Therefore the study of replacing body area with inexpensive steel material excluding O-ring and contact area which demands high characteristics is needed. The development of WC-Ni base carbide alloy optimal bonding composition technique was accomplished in this study. To check out the influence of bonding temperature and time, bonding characteristics of sintering temperature was experimented. The bonding statuses of this test specimen were excellent. The hardness of specimen and bonding rate were measured using ultrasound equipment. In this work, Powder of WC (involved VC, Cr), Co and Mo2C mixed by attrition milling for 24hours. Nanostructured WC-27.6wt.%Ni-1.5wt.%Si-0.11wt.%VC-1.1wt.%B4C composite were fabricated at 1190°C by high temperature vacuum furnace. To check out the influence of bonding temperature and time, bonding characteristics of sintering temperature was experimented. Its relative density was about 99.7%. The mechanical properties (hardness and fracture toughness) were 87.2 HRA and 4.2 M·Pam1/2, respectively. The bonding status of this test specimen was excellent and the thickness of bonding layer was 20 ~30§ at 1050 and 1060°C bonding temperature.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1479-1483
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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