Papers by Keyword: Packing Density

Abstract: Five boro-tellurite glasses with chemical formula 55TeO₂-(12-x)B₂O₃-32ZnO-(1+x)Na₂O (TZBN), (x= 0; 1; 2; 3; 4; mole%) were successfully synthesized by conventional melt-quenching technique. The physical properties of the glass was studied to understand effect of partial substitution between B₂O₃ and Na₂O. The density was measured using pycnometer based on Archimedes law. The other physical properties can be obtained by assisted some mathematical equation. Refer to the measurement, the density was found decreased by 4.905 to 4.590 gr/cm³ because the molecular weight difference between B₂O₃ and Na₂O. Meanwhile the molar volume increased by 25.05 to 27.11 cm³/mole due to higher atomic radii of Na rather than B which raise NBO inside the glass network. Meanwhile, OPD, V_o, polaron radius, inter-ionic distance, packing density,and number of bond per unit volume consequently have been decreased. While the Field strength has increase due to stronger Na-O bonds. Reflects from the results the TZBN glasses could be used as active material for laser.

Abstract: Shortage of river sand and disposal of stone sludge are the problem of the construction and stone product industries, respectively. Utilization of stone sludge in mortar is one of the feasible strategies to solve these two problems. To study the effects of addition of stone sludge on the performance of mortar, 20 mixes of stone sludge powder mortar with various water/cement ratios and various stone sludge powder contents were produced for flowability measurement. To further study the governing mechanism of flowability and the packing densities of the solid proportions of the 20 mortar mixes were measured. Based on the packing density results, the average film thickness (AFT) of the 20 mortar mixes were calculated for flowability indication. Results proved that addition of stone sludge powder as sand replacement would decrease the flowability. The flowability was mainly governed by the AFT.

Abstract: This work presents the results of investigations of the topological characteristics of quartz raw materials of various mineral compositions crushed to the critical state of the dispersed layer under which the shape of the particles and the action of the electrostatic repulsion forces change.

Abstract: Two 3inch SiC boules were grown in a PVT setup using source material of different packing density. During the growth, in-situ computed tomography of the growing boules showed differences in the development of the growth interface. A slightly bent growth interface was found for the smaller packing density. For the higher packing density the resulting crystal exhibits the onset of 6 pyramidal facets on its flanks. Besides that, strong anisotropic lateral growth was found on its (000-1) facet. Numerical simulations show an impact of the powder on the thermal gradient in the growth cell and therefore on the supersaturation. It is discussed that a higher supersaturation can account for the anisotropy in the growth rate of the [1-100] and the [11-20] direction.

Abstract: This paper focuses on an iterative algorithm for setting and attaining particle packing densities by means of different concentrations of a matrix material. The mechanical properties of a product, such as fracture toughness, bending strength and thermal conductivity are directly dependent on the amount of matrix material present. A tape cast friction layer was developed, in order to investigate the dependence of the parameters of the RRSB distribution on concentration of matrix material. The results verify the calculation method of a solid mixture and show a linear dependence of the RRSB particle-parameter n on the concentration of matrix material (SiC-content).

Abstract: The characteristics of removing COD and nitrogen simultaneously in membrane aerated biofilm reactor (MABR) was investigated in different packing densities and circulation flow rates. The results show that better removal rates of COD and ammonia nitrogen are found under the packing density of 30%, which removal rates are 76% and 65% respectively. Observations through the electron microscopic and CCD camera reveal that the biofilm have a layered structure and the stable biofilm thickness is 1.652 mm. When the circulation flow rate is 7.62 L·min^-1, the highest removal rate of total nitrogen is 70%, meanwhile, the efficient mass transfer of the biofilm is ensured.

Abstract: In this study, an investigation was conducted to develop oil palm fiber from palm oil mill waste as a thermal insulator. The experimental study focused on comparisons of thermal conductivity and temperature gradient or difference between the existing commercial rockwool and the produced oil palm fiber as a thermal insulator for a chimney of steam packaged boiler. The experiments were conducted at different temperature ranges and packing density. The values of the measured thermal conductivity were found to be 0.02 W/m·K to 0.112 W/m·K for a packing density of 78, 96 and 112 kg/m³, and at a temperatures between 40 oC to 90 oC. The value of the thermal conductivity of the oil palm fiber showed an increase at higher temperatures and greater temperature gradient as compared to the rockwool insulator. Although not being able to match the values at higher temperatures and temperature difference, other factors such as the cost and the environmental benefits of using oil palm waste material should be taken into consideration and hence encouraging its use as at least a supplement to existing insulation materials.

Abstract: HPC and UHPC concretes are finding their ways both to new structures and to retrofitting of existing structures. Herein specific material properties as well as structural examples are discussed. New Codes and Recommendations provide description of material properties and design rules for HPC/UHPC structures and structural elements.

Abstract: For operating under outer space conditions besides providing originally specified protective function, coating should often ensure accomplishment of functional properties, for instance conductivity of electric current. The solution of this problem can be reached by adding powder fillers with specified functional properties into powder paint. The paper deals with development of technique for formation of protective conducting coatings by filling powder paints and treatment in planetary ball mill. For protection of magnesium alloy shells the technique is offered which combines formation of the oxidized sublayer, introduction of electroconductive filler, treatment of the powder mixture in the planetary ball mill and electrostatic deposition of sifted mixture of definite dispersion. This allows sinking of static electricity from cabinets of the equipment for the space-crafts applications in conditions of the outer space.

Abstract: The relationship between granule property, pressed green density and shrinkage of 92% alumina spray dried granules were studied for both simple and complex shapes. Two types of granules, the in-house granule (A) and the commercial granule (B), was observed morphology using microscopy and liquid immersion techniques. Examination of the granules showed that granule A have several undesirable features; agglomeration, hollow granules and non-spherical granules where granule B showed them to be unagglomerated and spherical. The mixture A and B were conducted to study the particle size distribution (PSD) and compared with Dinger-Funks ideal PSD. The result showed that granule mixture A: B 100:0 had closest PSD curve fitted but had lowest tapping and pressed green density than 70:30 and 30:70 mixtures. This is because the agglomerated shape in granule mixture 100:0 caused air gap in between granule contact resulting in low tap density. The specific fracture strengths of the granules can affect to the densification of green ceramic during pressing. Low pressed green density affected to a high amount of shrinkage during sintering and leading to small grain growth after sintered. The simple and complex shape follows the same trend in shrinkage.