Wyniki wyszukiwania - BazTech

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Termite Mound Soils for Sustainable Production of Bricks

Legese Alemu Mosisa, Kenate Tesfaye Geneti, Feyessa Fekadu Fufa

Studia Geotechnica et Mechanica

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2021

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Vol. 43, nr 2

142--154

EN

The article presents the alternative use of termite mound soils (TMSs) as full replacement for clay soils in brick production. TMSs from two localities, Jawaj and Sene, in Ethiopia were investigated for bricks production. The TMSs samples contained high SiO2 and Al2O3. The TMSs bricks were fired at different temperatures from 500 to 1,000°C. The obtained mean compressive strengths (σ), 18 and 14 MPa, were observed for bricks made from TMSs from Jawaj and Sene, respectively, at the optimum firing temperature of 700°C. The σ of TMSs bricks decreased as the firing temperature increased above 700°C, while for conventional clay soil brick, the σ increased with temperature beyond 700°C. The water absorptions and saturation coefficients of fired TMSs bricks decreased with increased firing temperature. The TMSs bricks meet the standard specification of dimension tolerance only along the height. All the TMSs bricks made from the two localities were not efflorescent. TMSs from Jawaj and Sene sites can be used as a raw material to replace the long-used clay soils for bricks production as a construction material for houses construction in rural and urban areas.

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Ceramics with adjustable dielectric properties based on the system SrO – TiO2 – SiO2

Lisachuk G., Kryvobok R. V., Pitak Y., Lapuzina O., Gusarova I., Lisachuk L., Grebenuyk A.

Przegląd Elektrotechniczny

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2018

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R. 94, nr 1

163--166

EN

This work presents the results of optimization of the compositions area of radio-absorbing ceramic. As a result of laboratory samples test, dependences “composition – property” was obtained, the choice of the most technologically advanced composition area and sintering temperature for manufacturing the radio-absorbing ceramic was substantiated. The optimal composition of the Sr- titanate ceramics is characterized by the following properties: water absorption (W = 1,3 %), dielectric permeability (ε = 115), density (ρ =4,35·103 kg/m3).

PL

W pracy przedstawiono wyniki optymalizacji powierzchni kompozytowej materiałów ceramicznych pochłaniających fale radiowe. W wyniku badań laboratoryjnych próbek uzyskano zależności "kompozyt - właściwość", uzasadniono wybór najbardziej technologicznie zaawansowanej powierzchni kompozytowej oraz temperatury spiekania dla wytwarzania materiału ceramicznego pochłaniającego fale radiowe. Optymalny ceramiczny kompozyt strontowo-tytanowy charakteryzuje się następującymi właściwościami: absorpcja wody (W = 1,3 %), przenikalność dielektryczna (ε = 115), gęstość (ρ =4,35·103 kg/m3).

3

Mechanical and Ballistic Properties of Spherical Single Base Gun Propellant

Boulkadid K. M., Lefebvre M. H., Jeunieau L., Dejeaifve A.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

90--104

EN

The effect of the initial temperature on the mechanical properties of spherical single base gun propellant was investigated by means of a compression test, which consisted of compression of a propellant bed conditioned at various initial temperatures. Following this mechanical treatment, the pressed grains (after thermal conditioning at ambient temperature) were tested in a closed vessel. The results from the combination of compression and closed vessel tests supported the assumption that there are two phenomena occurring inside the cartridge at low temperatures which compensate each other; the first is a decrease in the burning rate as the initial temperature is decreased, and the second is grain fracturing occurring on ignition. Additionally, a specific parameter, the specific surface area, turns out to be an appropriate parameter for quantifying the mechanical damage to the propellant grain resulting from the compression test. Tests on the aged propellant have also been conducted.

4

Temperature Sensitivity of Propellant Combustion and Temperature Coefficients of Gun Performance

Boulkadid M. K., Lefebvre M. H., Jeunieau L., Dejeaifve A.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 4

1005--1022

EN

One of the objectives of gun propellant research is to develop green formulations of gunpowder that should be less temperature sensitive than the current gun propellant. The temperature sensitivity of these new green formulations of the propellant should be measured to identify the less temperature sensitive green formulations. However, there are deficiencies in the methodologies for the measurement of the temperature sensitivity of gun propellants. Therefore, the aim of this investigation was to fill the gap by establishing a method for the measurement of the temperature sensitivity of deterred gun propellants by closed vessel tests. The temperature sensitivity of the burning rate of ball propellants and the temperature coefficients of gun performance were determined using closed vessel tests and ballistic firing, respectively. Specific definitions of temperature sensitivity and temperature coefficients were evaluated. The relation between these parameters has never been explicitly investigated previously. Assessing the temperature sensitivity of propellants by closed vessel tests is of added value to the range of ballistic tests if the results of these tests can be well correlated to the results of ballistic firings. Therefore, a comparison between both parameters was made. A correspondence has been observed between the temperature sensitivity of the propellant burning rate, as obtained from closed vessel tests, and the temperature coefficients as obtained from ballistic firings.

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Poradnik dla początkującego witrażysty. Malowanie witraża klasycznego. Odcinek 4. Farby

Bochacz A., Bochacz A.

Szkło i Ceramika

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2014

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R. 65, nr 5

46

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Firing temperature of a clay core sample in a bronze tripod from Daxinzhuang Site in China using TL techniques

Wu Y., Jin Z., Fan A., Fang H.

Geochronometria

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2013

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Vol. 40, no. 4

317--321

EN

In this paper, we studied the thermal history of a clay core sample from one leg of a bronze tripod unearthed at Daxinzhuang Site, Shandong, China. The properties of the luminescence signals of quartz depend on the maximum temperature at which the quartz was annealed in the past. We ex-amined the feasibility of measuring the thermoluminescence (TL) sensitivity change of quartz for ex-ploring the firing temperature of archaeological materials. The sensitization factor of the 110°C TL peak (S2/S1) and the ratio of the 210°C TL peak to the 110°C TL peak at different annealing tempera-tures were utilized to unveil the firing temperature in the clay core sample. The firing temperature of the clay core sample was approximately 700°C-800°C, proving the clay core has been fired. This re-sult proved that the clay core has been fired by human agencies and indicated on the temperature of the clay core in drying and firing given by the foundry workers before the actual casting step.