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Combined Effect of Silicon Dioxide and Titanium Dioxide Nanoparticles on Concrete Properties

Al-Rbaihat Raed, Al-Marafi Mohammad Nour

Journal of Ecological Engineering

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2023

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Vol. 24, nr 12

319--335

EN

Nanoconcrete is an attractive research area because of its recent practical applications in building materials technologies. This study investigates the individual and combined effects of using nanoparticles in concrete mixtures as a cement substitute. Microscopic images are also used to determine changes in the microstructure of modified concrete in the present study. Concrete’s thermal and mechanical properties, including thermal conductivity (k), specific heat capacity (C), thermal diffusivity (α), and compressive strength (σ), are the leading concrete characteristics examined. The current study used different percentages (0%, 1%, 3%, and 5%) of nano-SiO2, nano-TiO2, and combined nano-SiO2/TiO2 particles as cement substitutes for 7 and 28 days of curing to examine the characteristics of nanoconcrete compared to conventional concrete (CC). The results indicated that adding individual nanoparticles to CC could improve concrete’s thermal and mechanical properties. Among the investigated nanomaterials (nano-SiO2, nano-TiO2, and combined nano-SiO2/TiO2 particles), nano-SiO2 was superior in that context. The optimal thermal properties of nanoconcrete were achieved when 5% nano-SiO2 (C-S5 specimen) was added. The k and α coefficients of sample C-S5 compared to the CC specimen were reduced by 65.6% and 80.3%, respectively, while the C coefficient was increased by 12.8%. Meanwhile, the optimal compressive strength coefficient of nanoconcrete was achieved when 3% nano-SiO2 (C-S3 specimen) was added, where the compressive strength coefficient of sample C-S3 compared to sample CC was increased by 19.6%. In contrast, for the combined effect, the thermal properties of concrete were improved, but the compressive strength coefficient of concrete was reduced. Overall, the present experimental findings offer valuable information about the impact of nanotechnology on high-performance concrete to save energy in buildings.

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System of heat supply ’ad hoc’ with solar wall

Shapoval S., Zhelykh V., Kapalo P., Venhryn I., Dacko O.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2018

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z. 65, nr 4

49--56

EN

For the implementation of solar thermal installations it is necessary to optimize energy-efficient external enclosures due to the correct installation and design of these units at different orientations of external walls. Investigated the effectiveness of using solar energy in the conditions of shortage of energy in Ukraine. Ad hoc solar wall look at two modes of its operation. Given a variety of graphical, analytical expressions for understanding the operation of the proposed design. Given these changes of the heat carrier temperature solar wall income the amount of the specific instantaneous heat output through time. The article considers the possibility of using experimental models, solar wall under the influence of her unfavourable ad hoc factors. It is established that the proposed model is solar wall is quite effective and can be used in solar heating systems.

3

Induction heating laboratory stand for estimating thermal properties of a charge

Cieślak A., Zgraja J.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 3

57--60

EN

Study is presenting the description of the laboratory stand for estimating thermal properties of inductively heated charge and aspects associated with implementing arrangements and control procedures, measuring and data handlings. Results of conducted examinations and practical conclusions resulting from analysis of problems that come across in the performance of a task were made.

PL

Opracowanie przedstawia opis stanowiska laboratoryjnego do szacowania cieplnych parametrów materiałowych indukcyjnie nagrzewanego wsadu oraz aspekty związane z wdrożeniem układów i procedur sterujących, pomiarowych oraz obróbki danych. Przedstawiono rezultaty przeprowadzonych badań oraz wnioski praktyczne wynikające z analizy trudności napotkanych w realizacji zadania.

4

NWA 6255 meteorite − Thermophysical properties of interior and the crust

Łuszczek K., Wach R. A.

Meteorites

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2014

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Vol. 3, No. 1-2

33--44

EN

Differences in the thermophysical properties of NWA 6255 meteorite samples obtained from various locations with respect o the distance from the surface of the meteorite were evaluated by a differential scanning calorimetry (DSC). DSC is a perfect tool to experimentally verify theoretically predicted thermophysical properties of extraterrestrial matter. The specific heat capacity of the crust and the interior of meteorite were determined to be in the temperature range of 223‒823 K. Measured Cp values at room temperature for crust and for the interior of this meteorite were 602 and 668 J·kg–1·K–1, respectively. In addition, the phase transition of troilite from: (a) the fusion crust samples, (b) the edge part of the meteorite (1‒2 mm below the crust), and (c) the interior (over 10 mm below the fusion crust) was examined. It is shown that the shift of α/β transition peak of the troilite exhibits the temperature gradient evolved during atmospheric passage of a meteoroid. Moreover, the enthalpy changes of α/β transition were used to determine the troilite content in the meteorite samples (3.6 wt.%). Obtained data are in agreement with previous Leco method’s results, since NWA 6255 is relatively fresh find (W1) and troilite tends to oxidized quickly.

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Thermophysical properties of the Sołtmany meteorite

Szurgot M., Wach R. A., Przylibski T.A.

Meteorites

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2012

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Vol. 2, No. 1-2

53--65

EN

Bulk density, porosity and thermophysical properties of the Sołtmany meteorite have been determined. The mean bulk density of the meteorite is 3.475‧103kg/m3, mean bulk density of the crust is 4.3‧103 kg/m3, grain density 3.71‧103 kg/m3, and porosity 6.4 ±} 0.4%. Mean specific heat capacity determined by DSC in temperature range between 223 and 823 K increases from 595 to 1046 J/(kg‧K), and is equal to 728 J/(kg‧K) at room temperature. Specific heat capacity of various samples is in the range 705–769 J/(kg‧K) at room temperature. Thermal capacity of Sołtmany chondrite is equal to 2.53‧106 J/(m3‧K), thermal diffusivity (1.5–1.8)‧10-6 m2/s, and thermal conductivity 3.9–4.5 W‧m–-1‧K-1at room temperature. Differential scanning calorimetry revealed two reversible phase transitions in the Sołtmany’s troilite: α/β transition at 423 K, and β/γ transition at 596.6 K.

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Porównanie gatunków żeliw szarych pod względem możliwości ich laserowej obróbki cieplnej

Kinal G., Paczkowska M.

Journal of Research and Applications in Agricultural Engineering

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2012

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Vol. 57, nr 1

73-76

PL

Artykuł dotyczy analizy właściwości różnych gatunków żeliw szarych (z grafitem w postaci płatków i sferoidów) o osnowach ferrytycznych, ferrytyczno-perlitycznych i perlitycznych, a także nierównowagowych przede wszystkim pod względem wpływu badanych właściwości na końcowy efekt laserowej obróbki cieplnej. Analiza wykazała, że można spodziewać się istotnych różnic w warstwie powierzchniowej pomiędzy różnymi gatunkami żeliw szarych po ich obróbce laserowej, a w szczególności zaobserwować można wyraźne różnice pomiędzy żeliwami o różnym kształcie grafitu. Wykazano, że zasięg zmian, jakie powoduje laserowa obróbka cieplna przeprowadzona w tych samych warunkach dla żeliw z grafitem sferoidalnym może być nawet parokrotnie większy niż żeliw z grafitem płatkowym. W celu uzyskania podobnych efektów należy w związku z tym zastosować wyższe wartości fluencji wiązki laserowej w przypadku żeliw płatkowych niż żeliw sferoidalnych.

EN

Presented paper refers to analysis of properties of different gray cast irons (with flake and spheroidal graphite) with ferrite, ferrite-pearlite, pearlite as well as unstable (for example bainite, maternsite) matrixes in the aspects of influence of these properties on the final laser heat treatment effect. The analysis showed that it is possible to expect essential differences in surface layer between cast irons with different graphite shape. It was shown that the range of changes caused by laser heat treatment performed in the same conditions for cast irons with spheroidal graphite can be several times larger than for cast irons with flake graphite. Consequently, to achieve the same effects it is necessary to apply higher laser beam fluence for flake cast irons than spheroidal cast irons.

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Pojemność cieplna właściwa stopów γ-TiAl z dodatkiem chromu i niobu

Przeliorz R.

Rudy i Metale Nieżelazne

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2007

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R. 52, nr 6

361-364

PL

Przedstawiono wyniki pomiarow pojemności cieplnej właściwej stopu γ-TiAl (L1o) z dodatkiem chromu (2 % at.) i niobu(2, 5, 7 % at.). Pomiary wykonano na różnicowym kalorymetrze kaningowym (DSC) w zakresie temperatury temperatury 423-1243 K. Krzywe cp można podzielić na trzy zakresy temperatury: T < 673 K, wysoki 673 K < T < 1073 K i bardzo wysoki T > 1073 K. Pojemność cieplna właściwa w zakresie temperatury od niskiej do umiarkowanej jest w przybliżeniu proporcjonalna do T3. W bardzo wysokiej temperaturz T>1073K na krzywej cp obserwuje się anomalię polegającą na gwałtownym wzroście pojemności cieplnej.

EN

In the article there are presented results of measurements of specific heat cap(acity alloy γ-TiAl(L1o) with addition chrome (2 % at.) and niobium (2, 5, 7 % at.). The measurements were performed on differential scanning calorimeter (the DSC) in range of temperature 423-1243 K. Curves cp can be divided on three ranges of temperature: moderate T<673 K, high 673K 1073 K. The specific heat capacity in range of temperature from low to moderate is in approximation proportional to T3. At very high temperature T > 1073 K we notice the beginning of an anomalous rise in the specific heat curve.

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The relationship between specific heat capacity and oxidation resistance of TiAl alloys

Przeliorz R., Goral M., Moskal G., Swadzba L.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 1

47-50

EN

Purpose: The results of the measuring of the specific heat capacity of the TiAl-based alloys with the addition of Cr and Nb, in temperatures ranging from 150 to 1000 degrees centigrade. Design/methodology/approach: The measurements of the specific heat capacity have been conducted using differential scanning calorimetry method (DSC) on Setaram calorimeter. The samples, sized 15 x 9 x 1,1 mm, have been oxidized in varied thermal conditions, according to the following scheme: 2 min. of heating up to 950 degrees centigrade, 50 min. of annealing at the given temperature, 8 min. of cooling until room temperature (25 degrees centigrade) was reached. Findings: The heat resistance of the alloys under the conditions of cyclic oxidation in 950 degrees centigrade has been specified. Up to 800 degrees centigrade, the course of the cp curves agrees with Debaye model. Above 800 degrees centigrade, an anomaly, involving the fast increase of the cp value, can be noticed. Research limitations/imlications: Results of investigation can explain relationship between specific heat capacity and oxidation resistance of different TiAl alloy. Originality/value: The presence of the Nb2O5 phase in the scale has been proved to spur the increase of the oxidation process.

9

Pojemność cieplna właściwa stopów na osnowie faz FeAl, TiAl, NiAl

Przeliorz R.

Rudy i Metale Nieżelazne

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2006

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R. 51, nr 6

347-350

PL

Badano pojemność cieplną właściwą stopów na osnowie faz międzymetalicznych FeAl i TiAl z dodatkiem Cr, Nb, Zr, Mo, C oraz fazy Ni3Al. W zakresie temperatury 423-1263 K średnia wartość pc dla stopu Fe36Al wynosi 0,53 kJ/kg ź K, zaś dla fazy Ni3Al 0,46 kJ/kg ź K. Pojemność cieplna właściwa dla stopu Ti48Al rośnie do temperatury 673 K. W zakresie temperatury 423-673 K średnia wartość cp = 0,55 kJ/kg ź K. W temperaturze 673 K następuje spadek pojemności cieplnej właściwej. Efekt ten związany jest z reakcją egzotermiczną . Ciepło reakcji wynosi –291 kJ/kg.

EN

The specific heat capacity of the alloys based on intermetallic FeAl and TiAl compounds with the addition of Cr, Nb, Zr, Mo, C and Ni3Al phase has been investigated. Between 423-1263 K the average value of cp for the Fe36Al amounts to 0.53 kJ/kg ź K, whereas for the Ni3Al it is 0.46 kJ/kg ź K. The specific heat capacity of Ti48Al alloy increases until 673 K. Within the range of 432-673 K the average value of pc equals 0.55 kJ/kg ź K. At the temperature of 673 K a decrease of the specific heat capacity occurs as a result of exothermal reaction. The heat of reaction amounts to –291 kJ/kg.