Papers by Keyword: Apparent Density

Abstract: In Algeria, the calcined dam's mud is a local renewable waste that proved its use as a supplementary cementitious material (SCMs) with similar mechanical performances and better resistance to several physical and chemical attacks than Portland cement. In the same context, the main objective of the work is to evaluate the effect of this calcined mud on thermal conductivity, which was never tested. To concretize this goal, one mortar based on control cement (CEMI) and three others based on modified cement by replacing CEMI by 10% to 30% Wt rates with the calcined mud of Chorfa dam have been prepared and cured before being put to the test procedure. Compressive strength, apparent density, water absorption after immersion, and thermal conductivity at three degrees of saturation state (saturated, outdoors, and dried state) were tested. The results show that using 10% to 20% replacement rate is characterized by good free lime and calcium hydroxide consumption that produces C-S-H gel, fills pores, decreases porosity, and increases density. The thermal conductivity of mortars based on the calcined mud in all states was lower compared than the control mortar, at saturated state by 16.28%, 17.83%, and 18.60% for the mortars 10%, 20%, and 30% (of cement replacement) respectively, at outdoors state by 5.5%, 4%, and 17.5% and dry state with 8.39%, 20.65%, and 38.07%. 10% to 20% mud replacement is beneficial for use in masonry and plastering wall applications of a building's envelope. 30% replacement rate can be developed and used in environments with minimal class expositions.

Abstract: The characteristics of Ni-Cr porous alloys containing 0.5 wt%Cr up to 12 wt%Cr were determined. The alloys were prepared from a mix of Ni-particles with filamentary shape and Cr-particles with irregular shape which then mixed with 0.5 wt% paraffin wax as a binder. The samples were formed by compaction and then sintered at 1200 °C for 1 h. The microstructure of samples was found to consist of a Ni-Cr solid solution matrix with X-ray energy dispersive analysis of Cr% less than 0.33 wt%. The matrix microstructure which composed of equiaxed grains (20-60 μm) surrounded high Cr content islands which also contained γ phase (Ni_2.88 Cr_1.22). The apparent density of the alloys was found to decrease with Cr content from 8.32 g/cm³ for samples containing 0.5 wt%Cr to 7.26 g/cm³ for samples containing 12 wt%Cr. Therefore, the estimated porosity was found to increase from 6.4% to 16.6% with increasing Cr content from 0.5 wt% to 12 wt%. The microhardness of the samples varied from 153.6 to 284.2 VHN for the equiaxed grains and from 119.6 to 240.6 VHN for the island areas.

Abstract: In this paper, titanium powders from various sources were characterized to compare powder intergrity for additive manufacturing by selective laser melting process. Selective laser melting by powder-bed based Additive Manufacturing (AM) is an advanced manufacturing process that bonds successive layers of powder by laser melting to facilitate the creation of engineering components. This manufacturing approach facilitates the production of components with high geometrical complexity that would otherwise be impossible to create through conventional manufacturing processes. Although the use of powder in AM is quite common, powder production and optimization of powder properties to yield desired performance characteristics has posed a serious challenge to researchers. It is therefore critical that powder properties be studied and controlled to ensure reliability and repeatability of the components that are produced. Typically, the desired feature of high quality titanium metal powders for AM are a combination of high sphericity, density and flowability. Scanning electron microscopy, EDS, particle size distribution and powder rheology were extensively performed to investigate the properties of gas-atomized Ti-6Al-4V powders.

Abstract: This paper studied the properties improvement of recycled coarse aggregate by the physical strengthening technology (particle-shaping method). Through the analysis for obtained properties which consist of density, crush index, bulk density and water absorption. etc of recycled coarse aggregates in different strengthening technologies, the categories of recycled coarse aggregate could be assessed and determined. The results showed that ordinary recycled coarse aggregates that was handled twice by using particle shaping equipment can achieve the standard of class Iaggregates and its water absorption ratio at 24h was 1.2%, the apparent density reached 2575kg/m³, crush index value was 9%, the void ratio was 45%, all property parameters were close to those of natural coarse aggregate.

Abstract: Silicon carbide (SiC) reticulated porous ceramics were prepared by organic foam impregnation, using polyurethane sponges as template and deionized water or alcohol as slurry solvent. The sintering behavior, microstructures and apparent density of struct of the SiC reticulated porous ceramics fabricated using the aqueous slurry under different sintering aids and sintering process and the alcohol slurry were investigated comparatively. The experimental results showed that both the microstructures and apparent density of the samples fabricated by Y₂O₃+AlN as sintering aid were better than those Al₂O₃ as sintering aid while the aqueous slurry, and the samples fabricated by two-step process (firstly heated to 700 oC in air furnace, and then sintered at 1800 oC in Ar atmosphere) while Y₂O₃+AlN as sintering aid obtained the optimal properties. In particular, the samples fabricated by the alcohol slurry and reaction sintering process were provided better properties than the aqueous slurry.

Abstract: It is important to take into account some more parameters, e.g. heat transfer coefficient, hygienic criterion or globalised energetic criterion, nowadays. It is a time when there is a big emphasize on thermal protection of residential buildings. Therefore an important calculation parameter is spoken more often - temperature loss and phase shift of thermal oscillation. This two parameters are very important especially in case of building envelopes based on lightweight supporting and used insulation materials. A pitched roof in residential building or family house is a typical example. This problem is growing even more, if we are taking adverse ratio of outer surface to volume of the space into account. This paper is showing analysis of such building envelope construction, its designing and influence on optimal values of phase shift of thermal oscillation.

Abstract: The aim of this paper is to develop new natural fibre reinforced for automotive brake pad application. For this purpose, new brake pad sampleswere produced using Miscanthus as reinforcement ingredient. The other ingredients are Cashew, Alumina, Phenolic Resin, and Calcite. Three different laboratory formulations were prepared with varying Miscanthus fibre contents from 10, 25, and 40 (wt) and these formulations were moulded four different moulding pressure values such as 50, 100, 200, and 300 MPa. Sieve analysis, density, apparent density, and hardness properties of brake pad samples produced are examined.

Abstract: In view of the traditional ceramsite using a large number of high-quality natural clay and shale, the destruction of the environment problem, ceramsite was prepared by kyanite tailings in Hebei, The results show that when the kyanite tailings and clay was in the ratio of 7: 3, the preheating temperature was 500°C, preheating time was 15min, calcination temperature was 1100°C, heat preservation time was 15min, the apparent density of ceramsite is 816kg/m3, the particle strength of 851N.

Abstract: The main function of the application software of the rapid inversion method of 3D apparent physical properties, and the key techniques used to achieve software are described in this paper. The core modules of the software is apparent physical properties inversion which can achieve the 3D apparent density and the 3D apparent magnetic inversion calculation, in addition, the software provides data preprocessing, reduction to the pole, the potential field continuation and potential field cut function. In software implementation process, first, compiling the calculation program modules by Fortran90 language, and then combining with dynamic link library, multi-threading and Surfer automated call technology, we compiled the visualization software interface to realize the function of the new method by C, C + + language, under the C + + Builder6.0 environment.

Abstract: The foamed composites could be completely biodegradable which was mainly prepared by corn starch and PVA as matrixes, reinforced by bamboo fiber, separately foamed by water, NH4HCO3 and AC/ZnO, plasticized by the mixed plasticizer of glycerol/urea and other adjuvants using extrusion foaming method. They were respectively called as WPS, NPS, APS. Then, the foamed composites’ apparent density, expansion ratio, water absorbtion, rebound rate, thermostability and cell morphology were discussed and compared with. The results showed that the apparent density decreased with increasing foamer content, then increasing; The apparent density of WPS、NPS and APS was respectively 0.24 g.cm-3, 0.27 g.cm-3, 0.15 g.cm-3; The expansion ratio increased with increasing foamer content, then decreasing; The expansion ratio of WPS, NPS and APS was respectively 63.8%、69.3%、75.4%; The water absorption increased with increasing foamer content, then decreasing; The water absorption of WPS, NPS and APS was respectively 71.3%, 64.4%, 73.4%; The rebound rate increased with increasing foamer content, then decreasing; The reboundrate of WPS, NPS and APS was respectively 54.3%, 46.8%, 58.3%; The thermostability of NPS was the best, and APS was the second, and WPS was the third. The number of cells was firstly increased with increasing foamer content, then decreasing and the side of cells became smaller with increasing content of foamer, then becoming larger.