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    Wyświetlanie 1-11 z 11
    Tytuł:
    Anisotropy of the neutron emission from PF-360 facility operated without and with solid-state targets
    Autorzy:
    Czaus, K.
    Baranowski, J.
    Sadowski, M.
    Skladnik-Sadowska, E.
    Zebrowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/146908.pdf
    Data publikacji:
    2001
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    anisotropy
    beam-target mechanism
    dense plasma focus (DPF)
    neutron yield
    thermal mechanism
    Opis:
    The paper reports on detailed studies of an anisotropy of the fusion-produced neutrons emitted from the modernized PF-360 facility [10], which has been operated with a pure deuterium-gas filling, without and with some additional solidstate targets containing deuterium atoms. Under standard operational conditions, anisotropy of the neutron yield from the PF-360 facility is similar to that observed in other PF devices. For the first time the neutron emission anisotropy has been measured in the PF experiments performed with a planar cryogenic target covered with a heavy-ice (D2O) layer. Changes in the Yn(Φ)/Yn(90°) ratio, particularly for angles Φ = 0–60°, have been explained by the known features of the angular distribution of fast deuterons.
    Źródło:
    Nukleonika; 2001, 46, suppl. 1; 77-80
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Decreasing of thermal errors in a lathe by forced cooling of ball screws and a headstock
    Autorzy:
    Winiarski, Z.
    Kowal, Z.
    Błażejewski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1429161.pdf
    Data publikacji:
    2008
    Wydawca:
    Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
    Tematy:
    lathe
    feed mechanism
    cooling
    thermal error
    calculation
    Opis:
    The goal of this paper is to present the effective methods of decreasing thermal deformations of a turning centre's structure in order to reduce the thermal error. The design of a machine tool as well as the scope of analyses are described, and calculation methods are specified. The paper also presents the results of computer simulations, concerning studies on the influence of type and parameters of a headstock-cooling liquid on the reduction of spindle displacements. Moreover, the results of feed mechanism's thermal studies are shown, describing the influence of heat generated during the operation of ball screws and their inner liquid cooling, on tool's thermal displacements.
    Źródło:
    Journal of Machine Engineering; 2008, 8, 4; 122-130
    1895-7595
    2391-8071
    Pojawia się w:
    Journal of Machine Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal behavior and kinetic decomposition of sweet potato starch by non-isothermal procedures
    Autorzy:
    Liu, Ying
    Yang, Liutao
    Zhang, Yingzhe
    Powiązania:
    https://bibliotekanauki.pl/articles/240460.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    starch
    kinetic analysis
    thermal degradation
    activation energy
    mechanism
    Opis:
    In this study, X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry (DSC) method were used to analyze the main characteristics of sweet potato starch, and to analyze the thermal degradation process of sweet potato starch. Specifically, X-ray diffraction to study its structure, thermogravimetric analysis to study the thermal degradation kinetics, and differential scanning calorimetry to study the thermogram of sweet potato starch. The thermal decomposition kinetics of sweet potato starch was examined within different heating rates in nitrogen atmosphere. Different models of kinetic analysis were used to calculate the activation energies using thermogravimetric data of the thermal degradation process. Activation energies obtained from Kissinger, Flynn-WallOzawa, and Šatava-Šesták models were 173.85, 174.87 and 174.34 kJ/mol, respectively. The values of activation energy indicated that the thermal degradation of the sweet potato starch was a single reaction mechanism or the combination of multi-reaction mechanisms. The differential scanning calorimetry analysis show that two decomposition stages were presented: the first at a low temperature involves the decomposition of long chain; and the second at a high temperature represents the scission of glucose ring. This information was helpful to design the processing process of many natural polymers. Thermogravimetric Fourier transform-infrared (TG–FTIR) analysis showed that the main pyrolysis products included water, methane, carbon dioxide, ammonia, and others.
    Źródło:
    Archives of Thermodynamics; 2019, 40, 4; 67-82
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental Insight into the Catalytic Mechanism of MFe2O4 (M = Ni, Zn and Co) on the Thermal Decomposition of TKX-50
    Autorzy:
    Hou, Xiaoting
    Zhang, Ming
    Zhao, Fengqi
    Yang, Yanjing
    An, Ting
    Li, Hui
    Pan, Qing
    Wang, Xiaohong
    Zhang, Kun
    Powiązania:
    https://bibliotekanauki.pl/articles/27788010.pdf
    Data publikacji:
    2021
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    bimetallic iron oxide
    thermal decomposition
    TKX-50
    catalysis
    mechanism
    Opis:
    Synthesized dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate (TKX-50) owes its outstanding application prospects in the field of insensitive solid propellants not only to its high energetic performance but also to its low mechanical sensitivity. Based on the excellent catalytic activity of bimetallic iron oxides for the thermal decomposition of TKX-50, the catalytic mechanism of bimetallic iron oxides (NiFe2O4, ZnFe2O4 and CoFe2O4) for TKX-50 pyrolysis has been explored. For this study, the decomposition process of TKX-50, before and after mixing with the bimetallic iron oxides NiFe2O4, ZnFe2O4 and CoFe2O4 was monitored by in-situ FTIR and gas-phase MS-FTIR instruments. Of the different catalysts, ZnFe2O4 gave the best result for reducing the initial decomposition temperature of TKX-50. Additionally, the activation energy of functional group cleavage of TKX-50, before and after mixing with ZnFe2O4, was also calculated for mechanism analysis from the results of the in-situ FTIR measurements. The results showed that the condensate and the gas-phase decomposition products of TKX-50 remained unchanged after mixing with different catalysts, while the activation energy of tetrazole ring cleavage was significantly reduced. The results of this study will be helpful for the rational design of insensitive solid propellant formulations containing TKX-50, and for understanding the pyrolysis mechanisms of TKX-50 before and after mixing with the efficient catalyst ZnFe2O4.
    Źródło:
    Central European Journal of Energetic Materials; 2021, 18, 2; 223--244
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Factors Affecting the Wear Resistance of Forging Tools
    Autorzy:
    Zwierzchowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/355784.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hot die forging
    wear mechanism
    forging
    laboratory thermal test
    Opis:
    The durability of forging tools is a function of many variables: tool heat treatment, surface quality, temperature, pressure, number of forgings, diffusion layers (nitriding) and many others. The objective of study was to analyze and compare the working conditions of forging tools. For the analysis of selected flat surfaces of tools. Analyzed forging dies subjected to normal use. Presented results of laboratory tests . The effect of temperature and time on the properties of the surface layer of forging tools. The results were compared with the literature data. This article shows the results of microhardness tests for forging dies which have forged the corresponding number of forgings. The results of laboratory studies on microhardness of hot working steel 1.2344 in the furnace at various temperatures and time are also presented. The working conditions of the forging tools are very complex. The most often described in the literature are: thermal fatigue, abrasive wear, mechanical fatigue and cracks. The article discusses the effects of increased temperature on the surface properties of forging tools. Forging dies were made of hot work tool steel 1.2344. FEM modeling of changes in the surface layer should take into account changes in tool hardness as a function of time (number of forgings).
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 3; 1567-1576
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigations into the degradation mechanism of thermal barrier applied in IC engine
    Autorzy:
    Hejwowski, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/242073.pdf
    Data publikacji:
    2009
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    thermal barrier coating
    spark ignited engine
    diesel engine
    phase stability
    degradation mechanism
    Opis:
    In the present paper the results of investigations into the degradation mechanizm of thermal barrier coating (TBC) applied in spark ignited and naturally aspirated diesel engines are presented. The TBC comprised 0.09 mm thick NiCrAlY bond coat and 0.36 mm thick Al2O3-40%TiO2 top coat. The coating was atmospheric plasma sprayed on piston heads, inlet and outlet valves and engine head. Top coating was heavily damaged in thermal fatigue tests and in exploitation test on spark ignited engine. The mechanism of damage was spalling of the outermost layer of ceramics. Porosity of the ceramic coating increased significantly which made the coating permeable to the products of combustion and thus facilitated corrosion attack on bond layer. Spalling of coating did not increase wear of piston rings and sleeves. X-ray diffraction studies proved high phase stability ofAl2O3-40%TiO2 top coat. Al2Or40%TiO2 APS sprayed coating cannot be considered the alternative top coat to currently used ZrO2-8%Y2O3in engine applications. Thermal barrier coating based on Al2O3-40%TiO2 can not be used for adiabatization of diesel or spark ignited engines. Al2O3-40%TiO2 based TBC can be used in less demanding applications.
    Źródło:
    Journal of KONES; 2009, 16, 3; 129-134
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on safe disposal of cephalosporins based on kinetic pyrolysis mechanism
    Autorzy:
    Fan, Jiangxue
    Zhang, Meng
    Hou, Xiaofei
    Wang, Fang
    Bai, Mengyuan
    Jiao, Ruoxi
    Yang, Zhongyu
    Duan, Erhong
    Cheng, Fengfei
    Zhou, Wen
    Powiązania:
    https://bibliotekanauki.pl/articles/27315672.pdf
    Data publikacji:
    2023
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Distillation residues
    Thermal analysis kinetics
    Template “3-2-2”
    Template “1+1”
    Pyrolysis mechanism
    Opis:
    Based on the global goals for cleaner production and sustainable development, the pyrolysis behavior of cephalosporin residues was studied by TG-MS method. The influence of full temperature window on the safe disposal of residues was analyzed based on the “3-2-2” and “1+1” of thermal analysis kinetics, and the gas by-products of thermal degradation were monitored. Results showed that the pyrolysis of distillation residues were divided into low and high-temperature zones, including six stages. Maximum error rate (8.55%) by multiple scan rate was presented based on “3-2-2” pattern and maximum total fluctuation (33.7) by single scan rate was presented based on “1+1” pattern, which implied that the comprehensive multi-level comparison method was very reliable. The E value “E” of six stages showed an increasing trend ranging 166.8 to 872.8 kJ/mol. LgA(mean) was 27.28. Most mechanism function of stage 1, 2 were Z-L-T equation (3D), stage 3, 4, 6 were Avrami-Erofeev equation (AE3, AE4, AE2/3) and stage 5 was Reaction Order (O2). In addition, various small molecular micromolecule substances were detected such as C2H4O, C2H6, NH3, CH4, CO2 under full temperature windows and a possible pyrolysis path of residues was provided.
    Źródło:
    Polish Journal of Chemical Technology; 2023, 25, 4; 52--60
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of the Thermal Decomposition and Combustion of Guanidinium 5,5’-Azotetrazole Salt
    Autorzy:
    Sinditskii, V. P.
    Levshenkov, A. I.
    Levshenkova, L. E.
    Powiązania:
    https://bibliotekanauki.pl/articles/358742.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    salt of 5,5’-azotetrazole with guanidine
    burning rate
    temperature profiles
    thermal decomposition
    combustion mechanism
    Opis:
    The thermal decomposition and combustion of guanidinium 5,5’-azotetrazole salt (Gu2AzT) have been investigated. Temperature profiles in the Gu2AzT combustion wave were measured using thin tungsten-rhenium micro thermocouples. It was shown that combustion of the salt obeys the condensedphase mechanism. The high burning rate of Gu2AzT is connected with the high decomposition rate in the melt. The kinetic parameters of the controlling chemical reaction have been estimated, and a detailed combustion mechanism for Gu2AzT has been proposed.
    Źródło:
    Central European Journal of Energetic Materials; 2013, 10, 4; 529-539
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study into combustion of sewage sludge as energetic fuel
    Badania spalania osadów ściekowych jako paliwa energetycznego
    Autorzy:
    Kijo-Kleczkowska, A.
    Środa, K.
    Otwinowski, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/219220.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    osady ściekowe
    termiczna utylizacja
    mechanizm i kinetyka spalania paliw
    sewage sludge
    thermal utilization
    fuel combustion mechanism and kinetics
    Opis:
    Along with the development of civilisation, it can be observed that the amount of waste of different type is growing and the preparation process for further usage of the waste or the utilization process differs. What is to be focused on is municipal sewage sludge which, due to its energetic properties, constitutes a valuable fuel. The problem of usage of municipal sewage sludge remains still unsolved, which stems both from the increasing amount of such waste, and from the lack of properly adjusted systems for thermal processing thereof. What is of an additional obstacle are the increasingly stricter legal regulations regarding disposal of sewage sludge after the year 2013; hence, it is necessary to consider various benefits resulting from thermal processing of such waste. This work presents an overview of methods of disposal of sewage sludge, taking into consideration, in particular, thermal methods including the process of combustion and co-combustion as a means of successful utilization. The research section of the work presents the results of study into the mechanism and kinetics of combustion of sewage sludge in various conditions of the process carried out in air flow. Combustion of sewage sludge has been compared against combustion of coal and biomass.
    Wraz z rozwojem cywilizacji zaobserwować można postępujące powstawanie różnego rodzaju odpadów różniących się, m.in. sposobem przygotowania do dalszego wykorzystania, czy procesem utylizacji. Na szczególną uwagę zasługują komunalne osady ściekowe, które z uwagi na właściwości energetyczne stanowią cenne paliwo. Problem wykorzystania komunalnych osadów ściekowych jest nadal otwarty, a wynika to zarówno z rosnącej produkcji tych odpadów, jak i braku odpowiednio przystosowanych instalacji do termicznego ich przekształcania. Dodatkowym utrudnieniem są zaostrzające się przepisy prawne dotyczące składowania osadów ściekowych po 2013 r. skłaniające tym samym do rozważań nad korzyściami płynącymi z termicznej obróbki tych odpadów. W pracy przedstawiono przegląd sposobów unieszkodliwiania osadów ściekowych ze szczególnym uwzględnieniem metod termicznych, głównie spalania i współspalania jako drogi do ich sukcesywnej utylizacji. W części badawczej pracy zaprezentowano wyniki badań mechanizmu i kinetyki spalania osadów ściekowych w różnych warunkach procesu prowadzonego w strumieniu powietrza. Spalanie osadów ściekowych porównano ze spalaniem węgla oraz biomasy.
    Źródło:
    Archives of Mining Sciences; 2013, 58, 4; 1085-1110
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stress evolution mechanism and thermo-mechanical reliability analysis of copper-filled TSV interposer
    Autorzy:
    Chen, Yuan
    Su, Wei
    Huang, Hong-Zhong
    Lai, Ping
    Lin, Xiao-ling
    Chen, Si
    Powiązania:
    https://bibliotekanauki.pl/articles/1841909.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    through silicon vias
    thermo-mechanical reliability
    failure mechanism
    finite element analysis
    3D integrated packaging
    thermal cycling experiment
    Opis:
    Through silicon via (TSV) has become one of the key emerging trends of three-dimensional (3D) packages, as it can realize vertically interconnect between stacked-dies. Due to large mismatch in thermal expansion coefficients (CTE) between the copper via and the silicon, significant mechanical stresses are induced at the interfaces when TSV structure is subjected to thermal stresses, which would greatly affect the reliability and electrical performance of TSV 3D device. In this paper, the relationship between the state of stresses and failure of TSV had been explored by combining finite element model simulation (FEM) and failure physical analysis. The position of the maximum stress of the TSV structure was obtained by FEM analysis. The relationship of stress and displacement change with temperature was also studied. And a thermal cycling experiment was conducted to validate the simulation results. Physical failure analysis after thermal cycling experiment was used to verify the degradation mechanism predicted by thermo-mechanical simulation.
    Źródło:
    Eksploatacja i Niezawodność; 2020, 22, 4; 705-714
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cavitation erosion phenomenological model of MCrAlY and NiCrMoNbTa metallic coatings deposited via the HVOF method
    Fenomenologiczny model erozji kawitacyjnej metalowych powłok MCrAlY I NiCrMoNbTa natryskiwanych metodą HVOF
    Autorzy:
    Szala, Mirosław
    Powiązania:
    https://bibliotekanauki.pl/articles/2055617.pdf
    Data publikacji:
    2021
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    cavitation erosion
    failure analysis
    wear mechanism
    thermal spraying
    microstructure
    roughness
    erosion rate
    erozja kawitacyjna
    analiza uszkodzeń
    mechanizm zużycia
    natryskiwanie termiczne
    mikrostruktura
    chropowatość
    szybkość erozji
    Opis:
    The work describes the phenomenological model of cavitation erosion (CE) elaborated for MCrAlY (where M = Co, Ni or Co/Ni) and NiCrMoNbTa. Coatings were deposited via the HVOF method from CoNiCrAlY, NiCoCrAlY and NiCrMoNbTa feedstock powders. CE tests, conducted according to ASTM G32 standard, indicate that MCrAlYs have a 50% higher maximum erosion rate and twice lower CE resistance than the NiCrMoNbTa coating. CE kinetics of coatings were comparatively studied, combining the mass loss, erosion rate, roughness changes of the eroded surface with microstructure, and mechanical properties of the coatings. Results of SEM analysis of damaged coatings allow identifying the mechanism of CE. In the case of both types of coatings, the erosive damage is initiated at the removal of loose splats, cracking at the border splats and peeling off the coating material, and surface pitting. However, NiCrMoNbTa, due to higher ductility and microstructure homogeneity, presents lesser surface pitting contrary to the MCrAlYs, which have multiphase microstructure higher hardness and consequently was prone to cracking, resulting in the formation of craters and higher surface roughening. The CE mechanism of MCrAlYs was dominated by the brittle mode, while the NiCrMoNbTa coating has mainly a ductile damage behaviour.
    W pracy opisano fenomenologiczny model erozji kawitacyjnej (EK) opracowany dla powłok MCrAlY (gdzie M = Co, Ni lub Co/Ni) i NiCrMoNbTa. Powłoki wytworzono metodą HVOF z komercyjnych proszków CoNiCrAlY, NiCoCrAlY i NiCrMoNbTa. Testy erozji kawitacyjnej, przeprowadzone zgodnie z normą ASTM G32, wskazują, że MCrAlY mają o 50% wyższą prędkość erozji i dwukrotnie niższą odporność EK niż powłoka NiCrMoNbTa. Kinetyka erozji kawitacyjnej powłok została poddana analizie porównawczej syntetyzującej utratę masy, szybkość erozji, zmiany chropowatości erodowanej powierzchni z mikrostrukturą oraz właściwościami mechanicznymi badanych powłok. Wyniki analizy SEM uszkodzonych powłok umożliwiły zidentyfikowanie mechanizmu EK. Uszkodzenie erozyjne powłok inicjowane jest w wyniku usuwaniu słabo umocowany cząstek materiału, pękaniu na granicach lameli następnie usuwaniu materiału i tworzeniu wżerów. Jednak NiCrMoNbTa ze względu na wyższą ciągliwość i jednorodność mikrostruktury wykazuje mniejsze wżery powierzchniowe w przeciwieństwie do MCrAlYs, które cechują się wielofazową mikrostruktura o wyższej twardości i w konsekwencji są podatne na pękanie, co powoduje powstawanie dużych wżerów i wyższe chropowacenie powierzchni. Mechanizm erozji kawitacyjnej powłok MCrAlY jest zdominowana przez kruche pękanie, natomiast w przypadku powłoki NiCrMoNbTa dominuje plastyczne odkształcenie.
    Źródło:
    Tribologia; 2021, 298, 4; 45--55
    0208-7774
    Pojawia się w:
    Tribologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-11 z 11

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