Residual post fire strength of non-prismatic perforated beams

The main aim of this study is to assess the performance and residual strength of post-fire non-prismatic reinforced concrete beams (NPRC) with and without openings. To do this, nine beams were cast and divided into three major groupings. These groups were classified based on the degrees of heating exposure temperature chosen (ambient, 400, and 700°C), with each group containing three non-prismatic beams (solid, 8 trapezoidal openings, and 8 circular openings). Experimentally, given the same beam geometry, increasing burning temperature caused degradation in NPRC beams, which was reflected in increased mid-span deflection throughout the fire exposure period and also residual deflection after cooling. But on the other hand, the issue with existing openings was exacerbated. The burned NPRC beams were then gradually cooled down by leaving them at ambient temperature in the laboratory, and the beams were loaded until failure to examine the effect of burning temperature degree on the residual ultimate load-carrying capacity of each beam by comparing them to unburned reference beams. It was found, increasing the exposure temperature leads to a reduction in ultimate strength about (5.7 and 10.84%) for solid NPRC beams exposed to 400 and 700°C, respectively related to unburned one, (21.13 -32.8) % for NPRC beams with eight trapezoidal openings, and (10.5 - 12.8) % for those having 8 circular openings. At higher loading stage the longitudinal compressive strain of Group ambient in mid-span of solid beams reach 2700 με, while the others with openings exhibit divergent strain higher than that, it’s about 3300 με meanwhile, the lower chord main reinforcements have been pass beyond yielding stress. Exposure to high temperatures reduces rafters’ stiffness causing a reduction in load carrying capacity, companion with premature failure consequently reduce the strain at the ultimate stage.

Effect of Calcination on the Chemical and Microstructural Properties of Sugarcane Bagasse Ash (SCBA)

This research study is for the evaluation of the effect of the burning temperature on the chemical and microstructural properties of Sugarcane Bagasse Ash. The Sugarcane Bagasse Ash (SCBA) is a byproduct of sugarcane which is dumped without proper handling and causing environmental issues because of the burning on dump site and loss of the area due to dumping in the commodity. The current research study is conducted for burning of SCBA on different temperatures and duration for finding the optimum burning temperature and duration of burning. The chemical and microstructural properties of SCBA evaluated at burning temperatures of 800°C for the duration of 01 hour, at temperature of 600° for the duration of 03 and 06 hours by conducting the tests of FTIR, XRD and XRF on the samples. The test results show that the burning temperatures of 800°C for the duration of 1 hour contains amorphous silica and also fulfilling the requirement of pozzolanic material (Composition of Silica, alumina and iron oxide is greater than 70%) as compared to other ash samples of sugarcane bagasse.

Effects of rice husk ash on itself activity and concrete behavior at different preparation temperatures

This paper aims to investigate the effects of rice husk ash (RHA) on itself activity and its concrete performance at different preparation temperatures for which three temperatures of 650 °C, 800 °C, and 900 °C were considered. To find a reasonable particle size, the effect of the particle size of the RHA on the workability of concrete at various grinding times was studied. A series of experiments were carried out to study the characteristics of the RHA, including X-ray fluorescence, XRD, ESEM, and an activity test. The carbonation resistance and frost resistance of concrete incorporating RHA were also investigated, where 10 and 30 wt.-% of cement was considered. The results show that the surface area of the RHA first increases and then decreases with grinding time. When the RHA is ground for 30 min, its surface area is largest and the workability of its mixture is also best. The burning temperature has little effect on the amount of SiO2. Although the structure and activity of SiO2 in RHA change at different burning temperatures, the performance of concrete incorporating RHA is higher than that of control concrete without RHA. With the same content of RHA, both carbonization resistance and frost resistance decrease with an increasing burning temperature of RHA. At the same burning temperature, both carbonization resistance and frost resistance increase with an increasing amount of RHA. Among all types of mixtures, the mixture incorporating 30 % RHA burned at 650 °C (i. e., RHA650) yields the best performance.

TIPOLOGI MOTIF HIAS TEMBIKAR SITUS PULAU KAMPAI, SUMATERA UTARA

Pottery is a human creation in the form of objects or containers made of clay which are burned at a burning temperature of 3500C-10000C. The pottery tradition began to be discovered during the cultivation period, in Indonesia pottery became known around 6000 BC, since then pottery has become one of the most important tools in human life. Pottery artifacts are often found at archaeological sites, either intact or in fragments. From the pottery data, there are several aspects that can be studied both in terms of form, decoration and function. The method used in this research is in the form of a special analysis, namely, by observing the attributes of decorative motifs on pottery at the Kampai Island Site, North Sumatra. The data used in this study were the findings of pottery from the excavation of the North Sumatra Archeology Center in 2013. The total number of pottery analyzed in total amounted to 974 shards. The purpose of this study was to determine the typology of decorative pottery motifs at the Kampai Island Site. The results of the research on the analysis of Kampai Island pottery motifs show that there are various decorative motifs so that the classification process of pottery decorative motifs is carried out which can produce several types or typologies of pottery decorative motifs in the Kampai Island Site, namely the types of motifs of lines, squares, circles, and triangles. Tembikar merupakan suatu hasil karya cipta manusia berupa benda atau wadah yang terbuat dari tanah liat yang dibakar pada suhu pembakaran 3500 C-10000 C. Tradisi tembikar mulai ditemukan pada masa bercocok tanam, di Indonesia tembikar mulai dikenal sekitar 6000 SM, yang sejak saat itu tembikar menjadi salah satu alat perlengkapan yang penting di kehidupan manusia. Artefak tembikar sering ditemukan pada situs arkeologi, baik utuh maupun pecahan. Data tembikar juga dapat diteliti dari beberapa aspek baik dari segi bentuk, hiasan maupun fungsi. Metode yang digunakan dalam penelitian ini berupa Analisis Khusus yaitu, dengan mengamati atribut motif hias pada tembikar Situs Pulau Kampai, Sumatera Utara. Data yang digunakan pada penelitian ini berupa temuan tembikar dari hasil ekskavasi Balai Arkeologi Sumatera Utara tahun 2013. Jumlah tembikar yang dianalisis secara keseluruhan berjumlah 974 pecahan. Adapun tujuan penelitian ini untuk mengetahui tipologi motif hias tembikar Situs Pulau Kampai. Hasil penelitian analisis motif hias tembikar Pulau Kampai menunjukan bahwa terdapat motif hias yang beragam sehingga dilakukan proses klasifikasi motif hias tembikar yang dapat menghasilkan beberapa tipe-tipe atau tipologi motif hias tembikar Situs Pulau Kampai, yaitu tipe motif garis, kotak, lingkaran, dan segitiga.

Controlling parameters of intake stroke of gas piston engines using the method of small deviations

A mathematical model of estimation of thermal and effective parameters of the most important part of cogeneration system of gas piston engine working in cogeneration mode was developed. Parameters of fresh air intake stroke with variable conditions of the environment using the method of small deviations were studied. The advantages of using the method of small deviations are the possibility of linearization of calculation equations as well as making calculations of not absolute but relative parameter change. The main parameters of fresh air intake by a cylinder are parameters of combustible mixture at the end of the intake stroke: combustible mixture pressure pa, the level of compression ε, the level of heating of fresh charge during the intake ΔT, parameters of residue gases (quantity Mr, pressure pr and temperature Tr), temperature of combustible mixture Tк. Using the method of small deviations for estimation of influence of the temperature of combustible mixture on effective values of gas piston engine led to an important finding: relative change of specific effective fuel consumption (economical part of gas piston engine exploitation) is in reverse relation to squared relative difference of temperature of supercharging air. In addition, cooling of supercharging air will positively influence temperatures inside engine cylinders and consequently fuel burning temperature. In turn, lowering the fuel burning temperature will improve ecological impact of the engine and reduce exhaust of harmful components into the atmosphere, in particular NOx.

Process of Obtaining Chromium Nitride in the Combustion Mode under Conditions of Co-Flow Filtration

In this work, the combustion process of chromium powder in the co-flow filtration mode was studied. The effect of nitrogen-containing gas flow rate on the nitridation of combustion products is shown. The effect of the amount of argon in the nitrogen–argon mixture on the burning rate and the burning temperature of the chromium powder is shown. It was found that an increase in the percentage of argon in the nitrogen–argon mixture can lead to the formation of an inverse combustion wave. The actual burning temperature is higher than adiabatic burning temperature in the co-flow filtration mode, thus the phenomenon of superadiabatic heating is observed. The phase composition of the obtained combustion products was studied. It was shown that the forced filtration mode allows for synthesizing non-stoichiometric Cr2N nitride.

Properties of Geopolymer Mortar Subjected to High Temperature

Geopolymer concrete was presented to produce alternative binder to cement. This study considered the influence of silica fume on the properties of metakaolin based geopolymer mortar exposed to high temperature up to 800 °C. Five mortar mixes were used with silica fume replacing level of 0, 10, 20, 30 and 40% of weight of metakaolin. The results demonstrated that the compressive and splitting tensile strength increased with increasing the silica fume replacing level up to 40% of weight of metakaolin for all burning temperature and the absorption was decreased with it. The outcomes also demonstrated that for the same mix the compressive and splitting tensile strength improved with increment burning temperature up to 400 °C and reduced with increasing the temperature above it until 800 °C.

Effect of the Ceramic Burning Temperature on the Characteristics of the Emission Spectrum (LIBS) of Al and Transmittance (FTIR) of Al-O on Ceramic Body of BL-1 Type

Aluminum (Al) contained in materials such as clay, kaolin is one of the elements that play an important role in the ceramic body. Al binds to other atoms like Si (quartz) to form a ceramic frame that is strong and not easily cracked. In addition, the bond with the group -OH plays an important role in relation to the ability of ceramics to absorb water. In this study, BL-1 type ceramic samples have been made with five variations of the burning temperature between 800-1000oC. To determine changes in the Al atomic content of ceramic samples were characterized by LIBS and FTIR spectrophotometers. The results of LIBS characterization of all samples showed two bands with peaks at wavelengths of 394.4 nm (Al-I) and 396.6 nm (Al-II) which are the characteristic peaks of Al atoms. The peaks with the highest intensity of Al-I and Al-II were resulted by samples that were burned at 900oC. Meanwhile, the results of FTIR characterization have shown a spectrum with bands at wavenumbers between 1030-1060 and 1150 cm-1 which are characteristic bands of stretching vibrations from Al-O. The peak of the band in the wavenumber between 1030-1060 cm-1 shifts towards a larger wavenumber with increasing the burning temperature.

The calculation of astrophysical S factors for E1 and E2 capture data of 12C(α , γ)16O reaction at 300 keV

The astrophysical S factors of E1 and E2 capture data of 12C( α , γ) reaction at 300 keV have been calculated based on our recent determined ANC values of 6.92 MeV and 7.12 MeV states of 16O using R-matrix. The S-factors are extrapolated into the range of burning temperature and the S-factors at 300 keV are S E1= (86 ± 34) keV b and SE2= (60 ± 33) keV b.