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Tytuł:
Plasma profile of cimicoxib in sheep after oral administration at two different rates
Autorzy:
Di Salvo, A.
Giorgi, M.
Lee, H.K.
Vercelli, C.
Rueca, F.
Trabalza Marinucci, M.
della Rocca, G.
Powiązania:
https://bibliotekanauki.pl/articles/2087920.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Źródło:
Polish Journal of Veterinary Sciences; 2017, 3; 535-538
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
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:
Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures
Autorzy:
Lee, J.-H.
Kim, D.-O.
Lee, K.
Powiązania:
https://bibliotekanauki.pl/articles/351774.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloys
rolling
strain rate
compression test
HSLA steel
Opis:
The hot deformation behavior of a heavy micro-alloyed high-strength low-alloy (HSLA) steel plate was studied by performing compression tests at elevated temperatures. The hot compression tests were carried out at temperatures from 923 K to 1,223 K with strain rates of 0.002 s-1 and 1.0 s-1. A long plateau region appeared for the 0.002 s-1 strain rate, and this was found to be an effect of the balancing between softening and hardening during deformation. For the 1.0 s-1 strain rate, the flow stress gradually increased after the yield point. The temperature and the strain rate-dependent parameters, such as the strain hardening coefficient (n), strength constant (K), and activation energy (Q), obtained from the flow stress curves were applied to the power law of plastic deformation. The constitutive model for flow stress can be expressed as σ = (39.8 ln (Z) – 716.6) · ε(−0.00955ln(Z) + 0.4930) for the 1.0 s-1 strain rate and σ = (19.9ln (Z) – 592.3) · ε(−0.00212ln(Z) + 0.1540) for the 0.002 s-1 strain rate.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1191-1196
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Atomistic Analysis Of Radiation-Induced Segregation In Ion-Irradiated Stainless Steel 316
Analiza w skali atomowej indukowanej promieniowaniem segregacji w stali nierdzewnej 316
Autorzy:
Lee, G.-G.
Jin, H.-H.
Chang, K.
Lee, B. H.
Kwon, J.
Powiązania:
https://bibliotekanauki.pl/articles/354713.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
atom probe tomography (APT)
radiation-induced segregation (RIS)
ion irradiation
irradiation defects
stainless steel
APT
RIS
stal nierdzewna
segregacja
Opis:
Stainless steel (SS) is a well-known material for the internal parts of nuclear power plants. It is known that these alloys exhibit radiation-induced segregation (RIS) at point defect sinks at moderate temperature, while in service. The RIS behavior of SS can be a potential problem by increasing the susceptibility to irradiation-assisted stress corrosion cracking. In this work, the RIS behavior of solute atoms at sinks in SS 316 irradiated with Fe4+ ions were characterized by atom probe tomography (APT). There were torus-shaped defects along with a depletion of Cr and enrichment of Ni and Si. These clusters are believed to be dislocation loops resulting from irradiation. The segregation of solutes was also observed for various defect shapes. These observations are consistent with other APT results from the literature. The composition of the clusters was analyzed quantitatively almost at the atomic scale. Despite the limitations of the experiments, the APT analysis was well suited for discovering the structure of irradiation defects and performing a quantitative analysis of RIS in irradiated specimens.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1179-1184
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Incorporation of Resonators Into Plenum Window
Autorzy:
Lee, H. M.
Haris, A.
Lim, K. M.
Xie, J.
Lee, H. P.
Powiązania:
https://bibliotekanauki.pl/articles/176744.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
plenum window
Helmholtz resonators
noise pollution
ventilation
Opis:
A plenum window with incorporation of Helmholtz resonators in between two glass panes was tested in a reverberation room. The effects of jagged flap on reducing strength of diffracted sound was also investigated in the present studies where white, traffic and construction noises were examined Turing each set of experiment. When the noise source was located at the central line of the plenum window, the plenum window with Helmholtz resonators was able to mitigate 8.5 dBA, 8.9 dBA and 8.2 dBA of white, traffic and construction noises, respectively, compared with the case of without window. These amounts of noises that attenuated by the plenum window were slightly higher than the case where noise source was diverged 30° away from the plenum window. The effects of jagged flaps on the acoustical performance of the plenum window were negligible. The Helmholtz resonators had the best performance in the frequency region between 900 Hz to 1300 Hz where in this frequency range, the plenum window with Helmholtz resonators was able to attenuate additional 1.7 dBA, 1.9 dBA and 1.6 dBA of white, traffic and construction noises, respectively, compared with the case of without resonators.
Źródło:
Archives of Acoustics; 2018, 43, 4; 739-746
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating
Powstawanie tlenku glinu na nośniku katalizatora FeCrAl przez osadzanie elektrochemiczne
Autorzy:
Yang, H. S.
Jang, D. H.
Lee, K. J.
Powiązania:
https://bibliotekanauki.pl/articles/355942.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FeCrAl
catalyst support
aluminum oxide formation
PEO
plasma electrolytic oxidation
electrochemical coating
nośnik katalizatora
tlenek glinu
plazmowe utlenianie elektrolityczne
elektrochemiczne osadzanie
Opis:
FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation) process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1503-1506
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Strut Thickness on Room and High Temperature Compressive Properties of Block-Type Ni-Cr-Al Powder Porous Metals
Autorzy:
Kang, B.-H.
Park, M.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/355591.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ni-Cr-Al
powder porous metal
strut thickness
high temperature
compressive behavior
Opis:
This study investigated the effect of strut thickness on the room and high temperature compressive properties of block-type Ni-Cr-Al powder porous metals with ~3000 μm pore size manufactured using a new powder process. Two block-type Ni-Cr-Al porous metals with different strut thicknesses were manufactured. The strut thicknesses of two block foams were 340 μm (A) and 383 μm (B), respectively. Room temperature, 500°C, 650°C and 800°C compressive tests were performed. The compressive results identified typical elastic, plateau and densification regions of foam material in all temperature conditions. Regardless of the strut thickness, compressive strength (maximum peak stress) decreased as deformation temperature increased. In all deformation temperature ranges, the compressive strength measured higher in the porous metal with greater strut thickness (B). The high temperature deformation behavior of powder porous metal was confirmed to be affected by the structural factor and microstructural factor of the porous metal. With the findings described above, this study also discussed the high temperature deformation mechanism of the Ni-Cr-Al metal foam based on fracture surfaces after the high temperature compressions.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1329-1334
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predicted small catchment responses to heavy rainfalls with SEGMO and two sets of model parameters
Przewidywane reakcje zlewni rzecznej na wysokie opady przy wykorzystaniu modelu SEGMO z dwoma zbiorami parametrów
Autorzy:
Krajewski, A.
Lee, H.
Hejduk, L.
Banasik, K.
Powiązania:
https://bibliotekanauki.pl/articles/81567.pdf
Data publikacji:
2014
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Opis:
The study tests the ability of hydrological part of SEGMO (SedimentGraph Model), i.e. lumped parametric rainfall-runoff procedure of SEGMO to simulate design storm runoff in a Korean catchment. The aim of the investigation is to predict responses of small catchment of the Jeungpyeong river, located in central part of South Korea, with the area of 133.6 km2, to 100-year rainfall events, applying SEGMO and using two parallel approaches for model parameter estimation. The first approach is based on catchment characteristics and USDA-SCS procedures, which is suitable for ungauged basins, and the other one is based on rainfall-runoff measurements. The way of estimation of model parameters has been demonstrated. Finally, the model outputs are compared. The difference in largest peak discharges obtained from SEGMO with the two sets of model parameters, i.e. when estimated on the base of catchment characteristics and USDA-SCS procedures, and on the base of rainfall-runoff measurements were relatively small, approaching 37%. This investigation can be seen as checking the uncertainties in model parameter estimation and their influence on flood flows.
Powodzie powodują straty społeczne, środowiskowe oraz ekonomiczne. Ryzyko związane z wystąpieniem powodzi wzrasta wraz z obserwowanymi zmianami klimatu i dotyczy coraz szerszego kręgu mieszkańców globu. W związku z tym, politycy, planiści i projektanci potrzebują informacji o skali zjawiska, które może wystąpić. Informacja ta musi być jednocześnie jak najbardziej wiarygodna. W zlewniach obserwowanych hydrologicznie istnieje możliwość zastosowania metod statystycznych w celu oszacowania przepływów maksymalnych prawdopodobnych. Alternatywą w małych zlewniach, gdzie zwykle brak wieloletnich danych pomiarowych, a które są również bardziej podatne na zmiany wpływające na ich reakcje, jest stosowanie modeli opad – odpływ. W pracy przedstawiono zastosowanie modelu SEGMO do wyznaczenia reakcji rolniczo- leśnej zlewni Jeungpyeong, o powierzchni około 134 km2, położonej w centralnej części Korei Południowej na opad prawdopodobny o p = 1% i różnym czasie trwania. Obliczenia wykonano w dwóch wariantach, określając parametry modelu: (1) na podstawie charakterystyki zlewni (jak dla zlewni nieobserwowanej) oraz (2) na podstawie pomiarów opad–odpływ. Przeprowadzone badania potwierdziły użyteczność modelu do symulacji reakcji zlewni na opady maksymalne, wysoką zgodność parametru CN wyznaczania opadu efektywnego, ustalonego jako wartość tablicową z wartości z danych pomiarowych, oraz dobrą zgodność wyników (maksymalnych przepływów) uzyskanych z zastosowania dwóch ww. sposobów ustalenia parametrów modelu. Wskazano na istotne elementy dalszych badań.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation; 2014, 46, 3
0208-5771
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder
Autorzy:
Lee, M.-W.
Bae, K.-H.
Lee, S.-R.
Kim, H.-J.
Jang, T.-S.
Powiązania:
https://bibliotekanauki.pl/articles/353351.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B sintered magnets
grain boundary diffusion process
low melting point element
DyCo alloy-powder diffusion
Opis:
We investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1st post annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2 Fe14 B and grain boundary phases covering Nd2 Fe14 B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3 phase.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1263-1266
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics Of The Porous Body Sintered By Nano-Sized Fe-Cr-Al Alloy Powder
Charakterystyka porowatego korpusu spiekanego z nanometrycznego proszku stopu Fe-Cr-Al
Autorzy:
Lee, S.-I.
Lee, S.-H.
Gu, B.-U.
Lee, D.-W.
Kim, B.-K.
Powiązania:
https://bibliotekanauki.pl/articles/356635.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-Cr-Al powder
metallic sponges
sintering temperature
oxidation resistance
proszek Fe-Cr-Al
proszek nanometryczny
temperatura spiekania
odporność na utlenianie
Opis:
Porous metal with uniform honeycomb structure was successfully produced by sintering using Fe-Cr-Al nano powder, which was prepared by the pulsed wire evaporation (PWE) in ethanol. Its process consisted of the several steps; 1) coating on the surface of polyurethane sponge with the liquid droplets generated from the ethanol-based slurry where the Fe-Cr-Al nano powders were uniformly dispersed, 2) heat treatment of debinding to remove the polyurethane sponge and 3) sintering of the porous green body formed by Fe-Cr-Al nano powders. The strut thickness of porous Fe-Cr-Al was increased by the increase of spraying times in ESP step. Also, The shrinkages and the oxidation resistance of the sintered porous body was increased with increase of sintering temperature. The optimal sintering temperature was shown to 1450°C in views to maximize the oxidation resistance and sinterability.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1275-1279
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Heat Treatment on the Microstructure and Tensile Deformation Behavior of Oxide Dispersion Strengthened Alloys Manufactured by Complex Milling Process
Autorzy:
Kim, Y.-K.
Kim, J.-H.
Gwon, J.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352535.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ball milling
oxide dispersion strengthening
microstructure
tensile deformation behavior
Opis:
This study attempted to manufacture an ODS alloy by combining multiple milling processes in mechanical alloying stage to achieve high strength and fracture elongation. The complex milling process of this study conducted planetary ball milling, cryogenic ball milling and drum ball milling in sequential order, and then the microstructure and tensile deformation behavior were investigated after additional heat treatment. The oxide particles distributed within the microstructure were fine oxide particles of 5~20 nm and coarse oxide particles of 100~200 nm, and the oxide particles were confirmed to be composed of Cr, Ti, Y and O. Results of tensile tests at room temperature measured yield strength, tensile strength and elongation as 1320 MPa, 2245 MPa and 4.2%, respectively, before heat treatment, and 1161 MPa, 2020 MPa and 5.5% after heat treatment. This results indicate that the ODS alloy of this study gained very high strengths compared to other known ODS alloys, allowing greater plastic zones.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1335-1340
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a high-speed air bearing spindle
Autorzy:
Ha, Y.-H.
Lee, D.-W.
Hwang, Y.-K.
Lee, C.-M.
Powiązania:
https://bibliotekanauki.pl/articles/1429126.pdf
Data publikacji:
2008
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
aerostatic bearing
metal foam
porous thrust bearing
porous radial bearing
Opis:
This paper investigates an air spindle with both radial and thrust air bearings of newly developing one-directional porous materials. At present, orifice type and porous type are adopted for thrust air bearings. Orifice type thrust air bearing is fabricated by machining several micro-holes on a bearing pad bearing, permeability significantly affected by particle size and machining conditions is an important factor of performance, but it is hard to c porosities is suggested. It has many micro-porosities through axial direction, so stable and plenty of air can be supplied to the thrust bearing pad. A radial air bearing also can be substituted by a radial direction porous bearing as the same reason. In case of driving parts, built-in motor type is widely applied. But it needs additional cooling parts to drop heat from a motor. So application of an air turbine drive with light-weight shaft is suggested and additionally it will reduce fabricating cost.
Źródło:
Journal of Machine Engineering; 2008, 8, 4; 25-31
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-parametric machine learning methods for evaluating the effects of traffic accident duration on freeways
Autorzy:
Lee, Y.
Wei, C.-H.
Chao, K.-C.
Powiązania:
https://bibliotekanauki.pl/articles/223569.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
accident on freeway
accident duration
effect evaluating
correlation
artificial neural networks
k-nearest neighbour method
wypadek na autostradzie
czas trwania wypadku
ocena skutków
korelacja
sztuczne sieci neuronowe
metoda najbliższego sąsiada
Opis:
Traffic accidents usually cause congestion and increase travel-times. The cost of extra travel time and fuel consumption due to congestion is huge. Traffic operators and drivers expect an accurately forecasted accident duration to reduce uncertainty and to enable the implementation of appropriate strategies. This study demonstrates two non-parametric machine learning methods, namely the k-nearest neighbour method and artificial neural network method, to construct accident duration prediction models. The factors influencing the occurrence of accidents are numerous and complex. To capture this phenomenon and improve the performance of accident duration prediction, the models incorporated various data including accident characteristics, traffic data, illumination, weather conditions, and road geometry characteristics. All raw data are collected from two public agencies and were integrated and cross-checked. Before model development, a correlation analysis was performed to reduce the scale of interrelated features or variables. Based on the performance comparison results, an artificial neural network model can provide good and reasonable prediction for accident duration with mean absolute percentage error values less than 30%, which are better than the prediction results of a k-nearest neighbour model. Based on comparison results for circumstances, the Model which incorporated significant variables and employed the ANN method can provide a more accurate prediction of accident duration when the circumstances involved the day time or drunk driving than those that involved night time and did not involve drunk driving. Empirical evaluation results reveal that significant variables possess a major influence on accident duration prediction.
Źródło:
Archives of Transport; 2017, 43, 3; 91-104
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation of Tungsten/Ammonium Perchlorate Composites and Their Reaction Kinetics
Autorzy:
Shim, H.-M.
Lee, E.-A.
Kim, J.-K.
Kim, H.-S.
Koo, K.-K.
Powiązania:
https://bibliotekanauki.pl/articles/358373.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ammonium perchlorate
composite
thermal decomposition
Opis:
The reaction kinetics of tungsten nanoparticles/ammonium perchlorate (W/AP) composites, produced by a spray drying technique, were analyzed and compared with those of neat AP particles and aluminum nanoparticles/AP (Al/AP) composites. The W was found to raise the onset temperature of the thermal decomposition of AP by increasing the activation energy, whereas Al conversely lowered the onset temperature of AP due to the decreased activation energy. From the master plots of kinetic models with the experimental data, the Prout-Tompkins model and the 1-D diffusion controlled model were found to describe the low-temperature decomposition (LTD) and high-temperature decomposition (HTD), respectively, giving remarkable agreement with experimental curves for all heating rates. The presence of W was found to increase the HTD zone width compared with that of neat AP particles and Al/AP composites. Analysis of the average activation energy and pre-exponential factor showed that W increases the energy barrier and the frequency of occurrence of the reaction compared with that of neat AP particles at the LTD state, whereas W decreases both of them at the HTD state. The effect of Al was also shown to be similar to that of W, but the magnitudes of the variation in activation energy and the pre-exponential factor were relatively small.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 4; 703-722
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spontaneous Formation of Titanium Nitride on the Surface of a Ti Rod Induced by Electro-Discharge-Heat-Treatment in an N2 Atmosphere
Autorzy:
Lee, W. H.
Yoon, Y. H.
Kim, Y. H.
Lee, Y. K.
Kim, J. Y.
Chang, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/352477.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
titanium
surface modification
diffusion
heat treatment
XPS
Opis:
A single pulse of 2.0 to 3.5 kJ of input energy from a 450 mF capacitor was applied to a commercially pure Ti rod in a N2 atmosphere. The surface of the Ti rod transformed from TiO2 into titanium nitride in times as short as 159 msec, providing a bimodal morphology of the cross-section. A much higher value of hardness that was observed at the edge of the cross-section was attributed to nitrogen-induced solid-solution hardening that occurred during the electrical discharge process. The activation energy (Ea) for the diffusion process was estimated to be approximately 86.9 kJ/mol. Results show that the electrical discharge process is a possible potential method for the nitriding of Ti; advantages include a short processing time and control of the nitrided layer without dimensional changes.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1281-1285
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 55

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