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Wyświetlanie 1-15 z 268
Tytuł:
Anti-Seismic Behavior of Welded Box Section Column Considering Welding Residual Stress at High Temperature
Autorzy:
Fu, Yadi
Dai, Xueyu
Zhang, Huidi
Wang, Yimin
Powiązania:
https://bibliotekanauki.pl/articles/2203725.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
box section
high temperature
residual stress
hysteretic behavior
Opis:
To study the anti-seismic performance of steel structure under high temperature, the finite element analysis software ABAQUS was used to study the seismic performance of Q235 steel welded box section column at service stage under normal temperature and high temperature fire. The effects of welding residual stress, slenderness ratio, width thickness ratio and axial load level on the hysteretic behavior of columns were analyzed and the stable bearing capacity and hysteretic performance of the column under high temperature were investigated. The results show that the maximum bearing capacity of the column decreases with the increase of the residual stress peak value. With the increase of temperature, a decrease in the maximum bearing capacity of columns under constant axial force and horizontal cyclic load and an increase in the ductility occur.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 5--13
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development on AI optimizing technology of NC program using tool free-cutting temperature for turning
Autorzy:
Tanabe, Ikuo
Isobe, Hiromi
Powiązania:
https://bibliotekanauki.pl/articles/2212054.pdf
Data publikacji:
2023
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
NC program
correction
free-cutting temperature
high productivity
tool condition
Opis:
In recent years, manufacturing must not only focus on high precision and productivity, but also on saving energy, resources and the environment. At the same time, there are increasing demands for high quality, high grade, wear resistance, heat-resisting property and high rigidity in machining workpieces. Therefore, for example, when creating NC programmes for machining difficult-to-machine materials such as titanium alloys and nickel alloys used in the aerospace industry, it has been very difficult to determine their optimum cutting conditions and create highly productive NC programmes due to lack of experience. Therefore, an AI optimizing technology of NC program using tool free-cutting temperatures for turning was developed and evaluated. The turning was used for this research and neural networks were used for AI optimizing. The algorithm for optimizing NC program using tool free-cutting temperature was firstly developed. Then the AI optimizing program for NC program was developed by C programming language. Previous NC program can rewrite for optimum condition by using the AI optimizing program. The proposed AI optimizing technology of NC program was evaluated by the several experiments. It is concluded from the results that; (1) The AI optimizing program for NC programmes using tool free-cutting temperatures in turning was developed, (2) The developed program was very useful for high productivity, long tool life and environmentally friendly.
Źródło:
Journal of Machine Engineering; 2023, 23, 1; 57--70
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discussion around IR material and structure issues to go toward high performance small pixel pitch IR HOT FPAs
Autorzy:
Gravrand, Olivier
Baier, Nicolas
Ferron, Alexandre
Rochette, Florent
Lobre, Clément
Bertoz, Jocelyn
Rubaldo, Laurent
Powiązania:
https://bibliotekanauki.pl/articles/2204207.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
mid-wave infrared
focal plane array
high operating temperature
small pitch
modulation transfer function
finite element method
Opis:
In the last decade, infrared imaging detectors trend has gone for smaller pixels and larger formats. Most of the time, this scaling is carried out at a given total sensitive area for a single focal plane array. As an example, QVGA 30 μm pitch and VGA 15 μm pitch exhibit exactly the same sensitive area. SXGA 10 μm pitch tends to be very similar, as well. This increase in format is beneficial to image resolution. However, this scaling to even smaller pixels raises questions because the pixel size becomes similar to the IR wavelength, but also to the typical transport dimensions in the absorbing material. Hence, maintaining resolution for such small pixel pitches requires a good control of the modulation transfer function and quantum efficiency of the array, while reducing the pixel size. This might not be obtained just by scaling the pixel dimensions. As an example, bulk planar structures suffer from excessive lateral diffusion length inducing pixel-to-pixel cross talk and thus degrading the modulation transfer function. Transport anisotropy in some type II superlattice structures might also be an issue for the diffusion modulation transfer function. On the other side, mesa structures might minimize cross talk by physically separating pixels, but also tend to degrade the quantum efficiency due to a non-negligible pixel fill factor shrinking down the pixel size. This paper discusses those issues, taking into account different material systems and structures, in the perspective of the expected future pixel pitch infrared focal plane arrays.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144561
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Temperature Oxidation Property of Ni Based Superalloy CM247LC Produced Via Selective Laser Melting Process
Autorzy:
Lee, Jung-Uk
Kim, Young-Kyun
Seo, Seong-Moon
Lee, Kee-Ahn
Powiązania:
https://bibliotekanauki.pl/articles/2203720.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ni-based superalloy
selective laser melting
directional solidification
microstructure
high temperature oxidation property
Opis:
CM247LC alloy was manufactured by using selective laser melting (SLM) process, one of the laser powder bed fusion (L-PBF) methods. The hot isostatic pressing (HIP) process was additionally conducted on the SLM-built CM247LC to control its microstructures and defects. The high temperature oxidation property was investigated, and it was compared with conventional DS247LC sample (reference) prepared via the directional solidification process. The L-PBF HIP sample showed blocky-type MC carbides generated along the grain boundary with average size of about 200 nm. A semi-spherical primary γ' phase of size 0.4-1.0 μm was also observed inside the grains. Moreover, the DS247LC sample displayed a coarse eutectic γ' phase and many script-type MC carbides. Furthermore, cuboidal-type γ' with an average size of about 0.5 μm was detected. High-temperature oxidation tests were conducted at 1000°C and 1100°C for 24 hours. The results at 1100°C oxidation temperature showed that the measured oxidation weight gains for HIP and DS247LC were 1.96 mg/cm2 and 2.26 mg/cm2, respectively, indicating the superior high-temperature oxidation resistance of the L-PBF HIP sample. Based on the above results, a high-temperature oxidation mechanism of the CM247LC alloys manufactured by the SLM process and the directional solidification process has been proposed.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 107--112
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-temperature oxidation of Fe40Al5Cr0.2TiB intermetallic phase-based alloy depending on its surface condition
Wysokotemperaturowe utlenianie stopu na osnowie fazy międzymetalicznej Fe40Al5Cr0,2TiB w zależności od stanu powierzchni
Autorzy:
Cebulski, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/41156843.pdf
Data publikacji:
2023
Wydawca:
Wydawnictwo SIGMA-NOT
Tematy:
FeAl alloys
high-temperature corrosion
scale
Al2O3 oxide
stop FeAl
korozja wysokotemperaturowa
zgorzelina
tlenek Al2O3
Opis:
The influence of an FeAl intermetallic phase-based alloy’s surface condition on the high-temperature corrosion process during annealing in air at 1000°C for 500 h was investigated. The structure of the oxide scale was determined and related to the initial surface condition before the oxidation process. Oxidation was observed using a Hitachi S-4200 scanning electron microscope. X-ray microanalysis of the chemical composition (EDS) was also carried out for all the tested samples after oxidation. The relationship between the structure of the oxide scale layer and the type of surface before oxidation was demonstrated.
W pracy dokonano analizy wpływu stanu powierzchni na przebieg procesu korozji wysokotemperaturowej stopu na osnowie fazy międzymetalicznej FeAl podczas wyżarzania w powietrzu w temperaturze 1000°C przez 500 h. Określono budowę zgorzeliny tlenkowej i odniesiono te dane do stanu powierzchni przed procesem utleniania. Próbki po procesie utleniania obserwowano przy użyciu elektronowego mikroskopu skaningowego Hitachi S-4200. Przeprowadzono również mikroanalizę rentgenowską składu chemicznego (EDS) wszystkich badanych próbek po utlenianiu. Wykazano zależność pomiędzy budową warstwy zgorzeliny tlenkowej a rodzajem powierzchni przed utlenianiem.
Źródło:
Ochrona przed Korozją; 2023, 5; 139-142
0473-7733
2449-9501
Pojawia się w:
Ochrona przed Korozją
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-temperature oxidation of Fe40Al5Cr0.2ZrB and TiAl intermetallic phase alloys
Wysokotemperaturowe utlenianie stopów na osnowie fazy międzymetalicznej Fe40Al5Cr0,2ZrB i TiAl
Autorzy:
Cebulski, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/41157525.pdf
Data publikacji:
2023
Wydawca:
Wydawnictwo SIGMA-NOT
Tematy:
FeAl
TiAl
corrosion
high-temperature corrosion
scale
Al2O3 oxide
korozja
korozja wysokotemperaturowa
zgorzelina
tlenek Al2O3
Opis:
A comparison of high-temperature corrosion resistance was carried out between Fe40Al5Cr0.2ZrB intermetallic phase-based alloy and TiAl alloy by annealing in air at 1000°C for 50 h, 100 h, 200 h, and 500 h. The extent of oxide scale formation on the surface of both alloys was determined and related to the initial surface condition before the oxidation process. The surfaces of both materials were analyzed and compared after the same annealing time. The surface condition before and after oxidation was examined using a stereoscopic microscope. The kinetics of the oxidation process at 1000°C over a period of 500 h were determined. Samples after oxidation were observed using a Hitachi S-4200 scanning electron microscope. Additionally, energy-dispersive X-ray spectroscopy (EDS) was performed to analyze the chemical composition of all tested samples of both materials after oxidation. The relationship between the occurrence of corrosion products for each of the tested materials and the annealing time was demonstrated.
W pracy dokonano porównania odporności na korozję wysokotemperaturową stopu na osnowie fazy międzymetalicznej Fe40Al5Cr0,2ZrB i stopu TiAl poprzez wyżarzanie w powietrzu w temperaturze 1000°C przez 50 h, 100 h, 200 h i 500 h. Określono powierzchnię zgorzeliny tlenkowej obu stopów i odniesiono te dane do stanu powierzchni przed procesem utleniania. Przeanalizowano i porównano powierzchnie obu materiałów po jednakowym czasie wyżarzania. Badania stanu powierzchni przed utlenianiem i po utlenianiu wykonano za pomocą mikroskopu stereoskopowego. Wyznaczono kinetykę procesu utleniania w temperaturze 1000°C w czasie 500 h. Próbki po procesie utleniania obserwowano przy użyciu elektronowego mikroskopu skaningowego Hitachi S-4200. Przeprowadzono również mikroanalizę rentgenowską składu chemicznego (EDS) wszystkich badanych próbek obu materiałów po utlenianiu. Wykazano zależność między występowaniem produktów korozji każdego z badanych materiałów a czasem wyżarzania.
Źródło:
Ochrona przed Korozją; 2023, 6; 170-174
0473-7733
2449-9501
Pojawia się w:
Ochrona przed Korozją
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of increased temperature of lower end-fitting of a composite long rod insulator on its mechanical strength under variable loads
Autorzy:
Bielecki, Jerzy
Kotowski, Piotr
Wańkowicz, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/24202743.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
composite suspension line insulators
high temperature low sag
HTLS
conductor
mechanical insulator strength
material fatigue
insulator tests
cyclic load
changing load
Opis:
This paper describes results of tensile mechanical strength testing of two types of composite suspension line insulators from two manufacturers. In order to take into account the operation of composite insulators in overhead transmission lines with high-temperature low-sag (HTLS) conductors, the testing of their static and fatigue strength was performed at both ambient and elevated temperatures. The results showed that the static mechanical strength of composite insulators decreased with an increase in the temperature of the lower end fitting of the insulator, and proved that it followed a third-degree polynomial function. Calculations performed demonstrated that a significant cause of reduction in strength was the increase in the radial stress following the temperature increase in the crimped glassepoxy resin core of the insulator. The results of the fatigue strength testing demonstrated that the increase in the temperature of the lower end fitting of the insulator up to 85°C degree had a little effect on the fatigue strength of the tested composite insulators.
Źródło:
Archives of Electrical Engineering; 2023, 72, 2; 392--405
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of temperature and nitrogen pressure on the test without active gases for high-temperature proton exchange membrane fuel cells
Autorzy:
Rosiński, Wojciech
Turpin, Christophe
Wilk, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/27309932.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
HT-PEMFCs
High-Temperature Proton-Exchange Membrane Fuel Cells
state of health
TWAG
Test Without Active Gases
Opis:
High-Temperature Proton-Exchange Membrane Fuel Cells (HT-PEMFCs) are a candidate for electrical energy supply devices in more and more applications. Most notably in the aeronautic industry. Before any use, an HT-PEMFC is preheated and after that supplied with its active gases. Only at this state, the diagnostics can be performed. A method of testing not requiring a complete start-up would be beneficial for many reasons. This article describes an extended version of the charging and discharging diagnostic method of HT-PEMFCs with no active gases. This extended approach is named “Test Without Active Gases” (TWAG). This paper presents original research on the influence of nitrogen temperature and pressure on the HT-PEMFC response to charging and discharging. A lumped-element model of an HT-PEMFC is also presented. A numerical result of using this model to recreate an experimentally obtained curve is also presented.
Źródło:
Archives of Electrical Engineering; 2023, 72, 3; 571--583
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern materials used for environmental barrier coatings – a review
Nowoczesne materiały stosowane na powłoki EBC – przegląd
Autorzy:
Mokrzycka, Magdalena
Jopek, Jakub
Słyś, Anita
Góral, Marek
Ochał, Kamil
Powiązania:
https://bibliotekanauki.pl/articles/41156632.pdf
Data publikacji:
2023
Wydawca:
Wydawnictwo SIGMA-NOT
Tematy:
environmental barrier coatings
high temperature corrosion
oxidation
turbine blades
środowiskowe bariery cieplne
EBC
korozja wysokotemperaturowa
utlenianie
łopatki turbin
Opis:
In this article, the materials used for EBC coatings, representing next stage in the development of heat-resistant layers, and thermal barrier coatings are reviewed. In the introduction, the design of gas turbine is characterized, as well as the materials used for the hot part components and the requirements for protective coatings. Ceramic materials that can be an alternative to currently used nickel superalloys for turbine blades are also described. The requirements for EBC coatings were analyzed and then the various types of EBC coatings were characterized, as well as their degradation mechanisms.
W artykule dokonano krótkiego przeglądu materiałów stosowanych na powłoki EBC (environmental barrier coatings) reprezentujących kolejny etap zaawansowania warstw żaroodpornych i powłokowych barier cieplnych (TBC – thermal barrier coatings). Opisano konstrukcję turbiny gazowej i materiały stosowane do produkcji elementów części gorącej oraz wymagania w zakresie powłok ochronnych. Opisane zostały również materiały ceramiczne, które mogą być alternatywą dla obecnie stosowanych nadstopów niklu używanych do wytwarzania łopatek turbin. Przeprowadzono analizę wymagań dotyczących powłok EBC, a następnie scharakteryzowano poszczególne rodzaje tych powłok, a także mechanizmy ich degradacji.
Źródło:
Ochrona przed Korozją; 2023, 4; 104-112
0473-7733
2449-9501
Pojawia się w:
Ochrona przed Korozją
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photomultiplier tube signal conditioning for high-temperature applications
Autorzy:
Zezuliński, Kacper
Brosławski, Andrzej
Slipukhin, Ivan
Guzik, Zbigniew
Krakowski, Tomasz
Burakowski, Szymon
Kaźmierczak, Łukasz
Łubian, Grzegorz
Milewski, Piotr
Saworska, Gabriela
Trela, Krystian
Powiązania:
https://bibliotekanauki.pl/articles/24202756.pdf
Data publikacji:
2023
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
high-temperature environment
photomultiplier tube
preamplifier
radiation detector
scintillation
signal conditioning
Opis:
Ionizing radiation detection in harsh environment conditions often requires additional signal processing to match the requirements of the commercial data readout systems. The subject of this paper is the design of the high-temperature (HT) signal conditioning module that ensures the applicability of scintillation detectors that utilize photomultiplier tubes (PMT) with moderate sampling rate instrumentation. The design was developed for the operation in HT environments (up to 120°C). In order to achieve the optimal signal shape, the module combines a charge amplifi er and a low-pass fi ltering circuitry. An embedded power supply section makes it a complete, standalone unit requiring a single 12 V supplying line. A comprehensive analysis of the developed device, named “PreAmp Shape”, was conducted in order to prove the intended functionality over the different working conditions.
Źródło:
Nukleonika; 2023, 68, 4; 91--96
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Projekt GOSPOSTRATEG-HTR: rezultaty projektu
The GOSPOSTRATEG-HTR project results
Autorzy:
Boettcher, Agnieszka
Celińska, Agnieszka
Frelek-Kozak, Małgorzata
Migdał, Marek
Dąbrowski, Mariusz P.
Sęktas, Paweł
Sidło, Andrzej
Zakrzewska-Kołtuniewicz, Grażyna
Wawszczak, Danuta
Brykała, Marcin
Kiegiel, Katarzyna
Miśkiewicz, Agnieszka
Fuks, Leon
Herdzik-Koniecko, Irena
Chajduk, Ewelina
Starosta, Wojciech
Smoliński, Tomasz
Rogowski, Marcin
Pawelec, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2200637.pdf
Data publikacji:
2023
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
reaktor wysokotemperaturowy
prawo atomowe
paliwo TRISO
badania materiałowe
high-temperature reactor
atomic law
TRISO fuel
material tests
Opis:
Ochrona klimatu wymaga wdrożenia bezemisyjnych źródeł energii, takich jak reaktory jądrowe. Reaktory wysokotemperaturowe mogą stanowić doskonałe uzupełnienie wielkoskalowej energetyki jądrowej, poprzez zaopatrzenie rynku energetycznego w wysokotemperaturowe ciepło, do różnych procesów technologicznych. Pierwszym krokiem na drodze do wdrożenia technologii reaktorów wysokotemperaturowych w Polsce była realizacja projektu GOSPOSTRATEG-HTR. Niniejszy artykuł stanowi podsumowanie najważniejszych celów i osiągnięć projektu.
Climate protection requires the deployment of zero-emission energy sources, such as nuclear reactors. Hightemperature reactors can be a perfect complement to large-scale nuclear energy by supplying the energy market with hightemperature heat for various technological processes. The first step towards the implementation of high-temperature reactor technology in Poland was the implementation of the GOSPOSTRATEG-HTR project. This article is a summary of the most important goals and achievements of the project.
Źródło:
Postępy Techniki Jądrowej; 2023, 1; 9--19
0551-6846
Pojawia się w:
Postępy Techniki Jądrowej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on preparation and properties of porous ceramsites sintered with high-ash coal slime
Autorzy:
Zhu, Dan
Min, Fanfei
Lv, Wenbao
Powiązania:
https://bibliotekanauki.pl/articles/27323640.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-ash coal slime
porous ceramsites
sintering temperature
ash content
Opis:
In order to realize the resource and harmless utilization of high-ash coal slime in coal preparation plants, porous ceramsites were prepared by the high-temperature sintering method with coal slime as raw material. The influences of sintering temperature, sintering time and ash content on the properties of porous ceramsites were studied by experiments, and the phase composition, micro-morphology and pore structure characteristics of ceramsites were analyzed by XRD, SEM and BET. The experimental results showed that with the increase of sintering temperature and sintering time, the amount of molten liquid in ceramsite green bodies increased, the densification degree of ceramsites increased gradually, the bulk density and the apparent density increased gradually, and the water absorption and the apparent porosity decreased gradually. However, with the increase of coal slime ash content, the quantity of pores within ceramsites increased first and then decreased. When the coal slime ash content was 55%, the bulk density of porous ceramsite sample was 0.549g/cm3, the water absorption rate was 64.63%, the specific surface area was 19.40m2/g, the crushing rate and wear rate were 0.14%, with rough surface, porous structure and excellent water absorption performance, which met the optimum performance requirements of porous ceramsites. At the same time, this research also provides a new idea and method for the reuse of high-ash coal slime resource, a by-product of coal washing and dressing.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 172665
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of high temperatures on the work of a firefighter in Nomex protective gear
Autorzy:
Dwornik, Tadeusz
Binkowska, Aneta
Powiązania:
https://bibliotekanauki.pl/articles/13925525.pdf
Data publikacji:
2023-09
Wydawca:
Towarzystwo Pomocy Doraźnej
Tematy:
Firefighters
high temperature
hyperthermia
protective gear
Nomex
efficiency
Opis:
INTRODUCTION: For firefighters to respond effectively and safely in challenging situations, their protective gear must offer maximum protection, comfort, and ergonomics. While this gear protects against high temperatures, it can pose risks in other scenarios. Specialised attire safeguards against fires but can be perilous in localised threats, potentially life-threatening. This is associated with increased internal body temperature, causing rapid breathing, elevated heart rate, increased blood flow and pressure, substantial sweating, and loss of essential elements. The study aimed to compare physical stress levels at high and low ambient temperatures and examine the variations in measured parameters. MATERIAL AND METHODS: This study assesses how working in high temperature conditions wearing firefighter gear affects physical and psychological abilities and recovery between tasks. It evaluates participants' well-being before and after the study, years of service, protective gear comfort, fluid intake, alternatives to standard gear, and recovery time. It uses questionnaires and measurements of vital signs (body temperature, weight, blood pressure, oxygen saturation, heart rate) before and after physical exertion. RESULTS: A total of 152 participants participated in this study, with 30 during the winter season and 122 in the summer. The human body releases heat through convection, conduction, radiation, and evaporation. Maintaining normothermia is challenging at high temperatures. In summer, participants' weight increased due to sweating. After exertion, blood pressure diverged significantly, with the summer group showing a notable increase in systolic pressure, which stressed the need for hydration. Blood oxygen levels increased during exertion but normalised after rest. Pulse rates were similar at rest but significantly increased in the summer group after exertion, highlighting the importance of caution and hydration at high temperatures. CONCLUSIONS: Analysis of collected data, including medical assessments and surveys, clearly demonstrates the significant impact of working in high temperature conditions on the vital parameters of the participants. Prolonged heat exposure, primarily due to the insulating properties of specialised gear and resulting thermal discomfort, accelerates fatigue and exhaustion. This, in turn, leads to increased errors, slower responses, and potential health problems. To address this concern, the introduction of lighter uniform options, adjustments to legal regulations, and the inclusion of overheating risks in medical protocols should be considered as preventive measures.
Źródło:
Critical Care Innovations; 2023, 6, 3; 21-36
2545-2533
Pojawia się w:
Critical Care Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Sintering Temperature on the Microstructure of Coal-Ash Based Geopolymers
Autorzy:
Burduhos-Nergis, Dumitru Doru
Vizureanu, Petrica
Achitei, Dragos C.
Sandu, Andrei Victor
Burduhos-Nergis, Diana Petronela
Abdullah, Mohd Mustafa Al Bakri
Powiązania:
https://bibliotekanauki.pl/articles/28032460.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
geopolymers
alkali activation
microstructural analysis
sintered structures
high temperature exposure
Opis:
Currently, one of the main challenges of civil engineering and science materials engineers is to develop a sustainable substitute for Ordinary Portland Cement. While the most promising solution is provided by the geopolymerisation technology, most of the studied geopolymers are based on natural raw materials (kaolin). The metakaolin is mainly preferred because of its rapid rate of dissolution in the activator solution, easy control of the Si/Al ratio, and white color. However, its high cost prevents it from being widely used in geopolymer composites or other materials that can become an industrial alternative for Ordinary Portland Cement. Several studies have shown that geopolymers with good performance can also be obtained from secondary raw materials (industrial wastes such as coal ash or slag). This explains why countries with rapidly developing economies are so interested in this technology. These countries have significant amounts of industrial waste and lack a well-developed recycling infrastructure. Therefore, the use of these by-products for geopolymers manufacturing could solve a waste problem while simultaneously lowering virgin raw material consumption. This study evaluates the effect of replacing different amounts of coal ash with sand on the microstructure of sintered geopolymers. Accordingly, scanning electron microscopy and energy dispersive X-ray analysis were involved to highlight the morphological particularities of room-cured and sintered geopolymers.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 631--637
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The structure and properties of magnetic composites based on amorphous Fe alloys
Autorzy:
Jeż, Bartłomiej
Postawa, Przemysław
Nabiałek, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/27311420.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
bulk amorphous alloys
magnetic composites
high-temperature isostatic press
kompozyty magnetyczne
prasa izostatyczna wysokotemperaturowa
stop amorficzny
Opis:
Materials with so-called soft magnetic properties are an important object of material engineering research due to their potential application, among others, in the construction of low-loss transformer cores. Such properties are typical for alloys with an amorphous structure and with a high content of ferromagnetic elements: Fe, Co, Ni. Difficulties related with obtaining alloys which meet satisfactory dimensions result in the search for new solutions. One of them is the production of composites based on ferromagnetic powders obtained from amorphous alloys. This paper presents results of structure research for composite materials produced in a multi-stage production process. Magnetic composites were made on the basis of a bulk amorphous Fe70B20Y5Nb4Mo1 alloy produced by the injection method. On the basis of the obtained powder, two series of moldings were made: with 0.5% resin and covered with high-temperature varnish. Final composites were produced by using high temperature isostatic press. On the basis of the conducted research, it was found that the composites without resin are characterized by distinctly better magnetic properties as compared to resin-bonded composites.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 4; art. no. e144608
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 268

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