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Wyszukujesz frazę "Kim, K." wg kryterium: Autor


Tytuł:
A mixed control chart adapted to the truncated life test based on the Weibull distribution
Autorzy:
Khan, N.
Aslam, M.
Kim, K.-J.
Jun, C. -H.
Powiązania:
https://bibliotekanauki.pl/articles/406432.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
life test
Weibull distribution
attribute chart
binomial distribution
average run length
Opis:
The design of a new mixed attribute control chart adapted to a truncated life test has been pre-sented. It was assumed that the lifetime of a product follows the Weibull distribution and the number of failures was observed using a truncated life test, where the test duration was specified as a fraction of the mean lifespan. The proposed control chart consists of two pairs of control limits based on a binomial distribution and one lower bound. The average run length of the chart was determined for various levels of shift constants and specified parameters. The efficiency of the chart is compared with an existing control chart in terms of the average run length. The application of the proposed chart is discussed with the aid of a simulation study.
Źródło:
Operations Research and Decisions; 2017, 27, 1; 43-55
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study Of The Die Roll Height Of SHP-1 And SCP-1 Materials In The Fine Blanking Process
Badanie wysokości deformacji krawędzi wycinanych elementów ze stali SHP-1 i SCP-1 procesie wykrawania
Autorzy:
Lee, C. K.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/356499.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die roll
fine blanking
SCP-1
share speed
SHP-1
v-rings
krawędzie
wykrawanie
szybkość działania
deformacja
Opis:
The height of the die roll, the distance of the V-ring, and the shear rate were varied with the aim of investigating the effects of the applied changes on the fine blanking line in a cold-rolled and a pickled steel sheet, referred to as SCP-1 and SHP-1, respectively. Both materials consisted primarily of a ferrite phase with small amounts of impurities including F, Mn, and Cr. The distance was found to be a very important factor in controlling the shear of the V-ring in the fine blanking process. When the position of the V-ring was set at distances of 1.5 mm and 2 mm, the die roll height increased with increasing shear speeds from 6.4 m/min to 10 and 16 m/min. Analysis of the influence of the shear rate revealed that low rates resulted in the lowest die roll heights since the flow of material was effectively inhibited.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1397-1402
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of the local entropy generation rate in a porous media burner
Autorzy:
Mohammadi, I.
Esfahani, J. A.
Kim, K. C.
Powiązania:
https://bibliotekanauki.pl/articles/38597672.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
porous media burner
chemical kinetics
volumetric heat transfer
axisymmetric combustion
local entropy generation
excess air ratio
Opis:
In this paper, the work and performance of the premixed methane-air porous axisymmetrical burner have firstly been simulated numerically using the CFD tools. For this purpose the set of governing equations has been enriched by an additional energy equation in porous solid, and the chemical species transport has been extended onto the multi-step mechanism (GRI-2-11). This numerical model has been verified on the base of available benchmark experiments. Next, we have studied the local entropy generation problem taking into account not only classical contributions like viscous and turbulent dissipation but also, the porous combustion of gases. The results showed that the greatest portion of entropy generation in the porous medium burner is related to chemical reactions, followed by heat transfer, mass diffusion (mixing) and friction (viscous dissipation), respectively. According to the results, as the excess air ratio increases, the local entropy generation rate due to heat transfer and friction increases and the local entropy generation rate due to chemical reactions is decreased. Also, by increasing the volumetric heat transfer coefficient, the local entropy generation rate due to heat transfer decreases and the local entropy generation rate due to friction and chemical reactions increases. Also, the local entropy generation rate due to mixing does not show a significant change with the changing excess air ratio and volumetric heat transfer coefficient.
Źródło:
Archives of Mechanics; 2020, 72, 3; 257-279
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on Changes in Thickness of STS304 Material in the Progressive Drawing Process
Autorzy:
Lee, C. K.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/356710.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
body thickness
drawing
flange thickness
corner roundness
material thickness
Opis:
In the drawing process, the roundness of corners in the punch and the die are very important factors in determining the thicknesses of the product. The results clearly revealed that the thickness of a flange was increased and the thickness of body parts reduced when the roundness of the die entrance was small. The material thickness of the top part was decreased when the corner roundness of the punch was large. The smooth inflow of materials was found to have a significant effect on the thickness during the post-process. The compressive strength of STS 304 material exhibited a higher value compared with other processing methods. Moreover, we clearly observed the corner roundness of the punch and the die to be a very important factor for STS 304 materials.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1319-1323
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media
Badanie stabilności dyspersji nanocząstek niklu wytworzonych metodą WEP w ciekłym medium
Autorzy:
Kim, C. K.
Lee, G.-J.
Lee, M. K.
Rhee, C. K.
Powiązania:
https://bibliotekanauki.pl/articles/356909.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nickel nanofluid
pulsed wire evaporation
surfactant
zeta potential
dispersion stability
nanocząstka niklu
środek powierzchniowo czynny
stabilność dyspersji
potencjał zeta
dyspersja
Opis:
In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles during the wire explosion. The dispersion stability of the prepared nickel nanofluids was investigated by zeta-potential analyzer and Turbiscan optical analyzer. As a result, the optimum concentration of polymer surfactant to be added was suggested for the maximized dispersion stability of the nickel nanofluids.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1379-1382
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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
Tytuł:
A Systematic Procedure for Modeling Usability Based on Product Design Variables: A Case Study in Audiovisual Consumer Electronic Products
Autorzy:
Kim, K.-J.
Han, S. H.
Yun, M. H.
Kwahk, J.
Powiązania:
https://bibliotekanauki.pl/articles/90811.pdf
Data publikacji:
2002
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
usability evaluation
human interface elements
consumer electronic products
produkty przemysłowe
ocena zgodności wyrobów
ocena użyteczności
produkty elektroniczne
Opis:
A systematic modeling approach to describing, prescribing, and predicting usability of a product has been presented. Given the evaluation results of the usability dimension (UD) and the measurement of the product’s design variables, referred to as the human interface elements (HIEs), the approach enables one to systematically assess the relationship between the UD and HIEs. The assessed relationship is called a usability model. Once built, such a usability model can relate, in a quantitative manner, the HIEs directly to the UDs, and thus can serve as an effective aid to designers by evaluating and predicting the usability of an existing or hypothetical product. A usability model for elegance of audiovisual consumer electronic products has been demonstrated.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2002, 8, 3; 387-406
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated framework for various operation plans in container terminals
Autorzy:
Won, S. H.
Kim, K. H.
Powiązania:
https://bibliotekanauki.pl/articles/258792.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
container terminals
planning
resource capacity
Opis:
This study provides a framework for integrating various planning activities in container terminals. First, we introduce various planning activities in container terminals and identify decision-making problems for each planning activity. Input parameters, decision variables, objectives, constraints, time buckets, and the planning horizon for each decision activity are identified. Next, we introduce the concept of a resource profile and planning procedure simultaneously by considering availabilities of various resources and resource requirements in a planning activity.
Źródło:
Polish Maritime Research; 2009, 3; 51-61
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and Optimization of Micro Speaker-Box Using a Passive Radiator in Portable Device
Autorzy:
Jiang, Y.-W.
Kwon, J.-H.
Kim, H.-K.
Hwang, S.-M.
Powiązania:
https://bibliotekanauki.pl/articles/176530.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
passive radiator
speaker box
SPL improvement
Sound Pressure Level
Opis:
With the rapid development of multimedia devices such as smart phones and tablet PCs, microspeakers have been recently increasingly used for audio equipment. Improving the acoustic performance of a microspeaker is always a main concern, especially in the low frequency range. To avoid sound cancelation, a microspeaker unit is usually inserted into a speaker box. A passive radiator is also used in speaker boxes to improve the sound performance in the loudspeaker system. However, passive radiators have not been applied into microspeaker system. In this study, a speaker box with a passive radiator was analyzed and optimized to achieve a higher Sound Pressure Level (SPL) in a microspeaker system. The Finite Element Method (FEM), two-degree-of-freedom (DOF) vibration theory, and a plane circular piston sound source were used to study the electromagnetic, vibration, and acoustic characteristics, respectively. Optimization was conducted by changing the mass, stiffness, and size of the passive radiator. Based on the optimized parameters, a new sample was manufactured. The experiment results show that the SPL of the optimized speaker box with a passive radiator is improved by 5 dB at 200 Hz compared with the one without a radiator. The analysis results also matched the experiment results.
Źródło:
Archives of Acoustics; 2017, 42, 4; 753-760
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of checklists for agricultural safety management
Autorzy:
Kim, H.
Rasanen, K.
Chae, H.
Lee, K.
Powiązania:
https://bibliotekanauki.pl/articles/2081898.pdf
Data publikacji:
2018
Wydawca:
Instytut Medycyny Wsi
Tematy:
checklist
agriculture
safety
management
Opis:
Introduction. The current health and safety management system under the Occupational Health and Safety Act has avoided agriculture in Korea. It is important to consider the various safety systems used in agricultural health and safety to develop effective regulations. Objective. The aims were to classify and review the items from various checklists using safety systems, such as design, training, etc., ultimately aimed at proposing directions for improving the health and safety of farmers. Materials and method. Among the retrieved checklists with Google, four were chosen for this study, based on criteria such as the Checklist developed by an international organization, as well as others. Each item on the checklist was categorized using criteria concerning safety systems, developed based on previous studies. Results. The total number of analyzed items was 573, which is 36 more than the actual number of checklist items (537). The proportion of items belonging to the training/procedures system was the highest (32.5%); the second-highest was for the mitigation system – 18.2%.; the third-largest proportion of items was maintenance/inspection – with 14.3%. Items related to the design and human factor systems were 8.2% and 5.6%, respectively. The safety system with the lowest proportion was the warning/notification system – 4.2% of the total items. The proportion of items that could not be classified into safety systems was found to be 16.1%. Conclusions. A large number of items belonging to the training/procedures system reported as occasionally not effective in prevention of injury were found in the checklists. It appears important to develop checklist items proposing the supplementation of various safety systems, rather than presenting items that are biased towards certain safety systems.
Źródło:
Annals of Agricultural and Environmental Medicine; 2018, 25, 3; 494-499
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis Of Drilling Of A Metal Plate With Pilot Hole
Analiza wiercenia metalowej płyty z otworem pilotującym
Autorzy:
Kim, K. S.
Powiązania:
https://bibliotekanauki.pl/articles/354541.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
finite element method
drilling
pilot hole
cutting force
plastic strain
metoda elementów skończonych
wiercenie
otwór pilotujący
siła cięcia
odkształcenie plastyczne
Opis:
This paper performed a numerical analysis study of the cutting characteristics when drilling a taper hole whose upper and lower diameters are different, that is, a pilot hole. 3-dimensional drilling analysis was performed using a commercial code, and these results were used to determine analytically and compare the cutting temperature, the phenomenon of cutting chip formation, deformation and pressure, etc., for the tools, chips, and specimens during cutting. Also, cutting force and the required energy were calculated and compared. To verify the results of analysis, a cutting dynamometer was used to analyze 3-axis cutting force. Results of analysis showed that the specimen maintained a temperature of approximately 650°, with rapid cooling after chips were formed from the specimen. The tool reached a maximum of 700°, similarly to the chips. It is expected that these results will be utilized to optimize cutting processes and work conditions when drilling holes.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1307-1310
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis Of The Extrusion Process Of A Square Tube Multi-Channel Heat Pipe
Analiza procesu wytłaczania wielokanałowych ciepłowodów o kwadratowym przekroju
Autorzy:
Kim, K. S.
Kim, J. Y.
Powiązania:
https://bibliotekanauki.pl/articles/353935.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum hot extrusion
FE simulation
stress analysis
extrusion experiment
aluminium wytłaczane na gorąco
symulacja FE
analiza naprężeń
wytłaczanie
Opis:
Heat pipes have been recently in use for cooling purposes in various fields, including electronic circuit boards and vehicle parts that generate large amounts of heat. In order to minimize the loss of heat transferred, there is a need to maximize the contact area of the working fluid. This study produced a square tube multi-channel heat pipe to replace the existing circular pipe type to maximize the internal surface area thereof. This expands the surface, allowing the working fluid to come into contact with a wider area and enhancing thermal radiation performance. A mold for the production for such a product was designed, and finite element simulation was performed to determine whether production is possible.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1463-1466
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Image Processing to Predict Compressive Behavior of Aluminum Foam
Autorzy:
Kim, S.
Chung, H. J.
Rhee, K.
Powiązania:
https://bibliotekanauki.pl/articles/357032.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum foam
compute tomography (CT) image
finite element method (FEM)
Opis:
An image processing technique was used to model the internal structure of aluminum foam in finite element analysis in order to predict the compressive behavior of the material. Finite element analysis and experimental tests were performed on aluminum foam with densities of 0.2, 0.25, and 0.3 g/cm3. It was found that although the compressive strength predicted from the finite element analysis was higher than that determined experimentally, the predicted compressive stress-strain curves exhibited a tendency similar to those determined from experiments for both densities. However, the behavior of the predicted compressive stress-strain curves was different from the experimental one as the applied strain increased. The difference between predicted and experimental stress-strain curves in a high strain range was due to contact between broken aluminum foam walls by the large deformation.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 635-640
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological Evaluation of Anodized Biodegradable Magnesium-Calcium Alloys
Autorzy:
Kim, J.
Lee, J.
Lee, K.
Park, S.
Lim, H.
Park, C.
Bae, J.
Yun, K.
Powiązania:
https://bibliotekanauki.pl/articles/1398763.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
87.85.J-
Opis:
The objective of this study was to evaluate the biocompatibility of studied binary magnesium-calcium (Mg-Ca) alloys for biodegradable intraosseous implants. Mg is necessary for health and is a non-toxic biodegradable material that decomposes naturally in the body. Nevertheless, Mg has been implicated in problems including diminished physical properties and corrosion resistance when degradation is too rapid prior to bone healing. This study has explored the effect of Ca on the corrosion resistance and biological evaluation after anodizing treatment with different contents of Ca alloy. Binary Mg-0.5Ca, Mg-1Ca and Mg-5Ca alloys were prepared by the casting method under an argon atmosphere and cut into disc-shaped pieces. Pure Mg alloy was used as the control. Anodic oxidation was performed for 15 minutes at a voltage of 120 V using an electrolyte solution containing Ca gluconate, sodium hexametaphosphate, and sodium hydroxide at room temperature. Corrosion resistance was analyzed using a corrosion tester. After a hydrogen evolution test, the surface pattern and phase changes were observed on a scanning electron microscop (SEM) and energy dispersive spectroscop (EDS). Microscopic evaluation of the adhesion and cell biological functions of Mg was conducted by observing the response of human fetal osteoblastic 1.19 cells with regard to changes in surface film properties, depending on the amount of Ca. Our results support the view that in Mg-xCa alloys (x=0.5, 1, 5 wt.%) treated using anodic oxidation, the increasing Ca content controls the rate of decomposition and improves corrosion resistance.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 728-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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