Evaluation Of Flowability Research Articles

Evaluation of Flowability and Floodability for Dynamic Powder Flow Based on Particle Characteristics

Evaluation of Flowability and Floodability for Dynamic Powder Flow Based on Particle Characteristics

粉体流動性評価への新たな視点―粉体基礎物性の分布に着目した解析―

粉体流動性評価への新たな視点―粉体基礎物性の分布に着目した解析―

Flowability of multi-sized mixed particles based on shotcrete aggregates

In the shotcrete construction process, the calculation and prediction of the flowability of multi-sized mixed aggregates is essential. Based on shotcrete aggregates, the bulk density, tapped density, and flowability evaluation parameters such as Hausner ratio (HR) and angle of repose (AoR) were measured for multi-sized mixed spherical and non-spherical particles. Mono-sized spherical and non-spherical particles were also used as a control. The results show that the particle bulk density, tapped density, and flowability for a mono-sized can be described as a function of particle size and Archimedes number (Ar). In addition, the particle size distribution of shotcrete aggregates is quantitatively described using the gradation equation, obtaining the functional relationship between the multi-sized mixed particles parameters and the Sp log , which is defined based on span function and gradation equation. Compared to HR, AoR enables a more detailed flowability classification of shotcrete aggregates. • The HR and AoR of multi-sized shotcrete aggregates are measured. • AoR measurement methods are compared. • The particle size distribution of shotcrete aggregates is described quantitatively. • Multi-sized mixed particle flowability parameters are related as a function of span.

Compaction behavior of powder bed fusion feedstock for metal and polymer additive manufacturing

Purpose Powder bed-based additive manufacturing (AM) is a promising family of technologies for industrial applications. The purpose of this study is to provide a new metrics based on the analysis of the compaction behavior for the evaluation of flowability of AM powders. Design/methodology/approach In this work, a novel qualification methodology based on a camera mounted onto a commercially available tap density meter allowed to assess the compaction behavior of a selection of AM materials, both polymers and metals. This methodology automatizes the reading of the powder height and obtains more information compared to ASTM B527. A novel property is introduced, the “tapping modulus,” which describes the packing speed of a powdered material and is related to a compression/vibration powder flow. Findings The compaction behavior was successfully correlated with the dynamic angle of repose for polymers, but interestingly not for metals, shedding more light to the different flow behavior of these materials. Research limitations/implications Because of the chosen materials, the results may lack generalizability. For example, the application of this methodology outside of AM would be interesting. Originality/value This paper suggests a new methodology for assessing the flowing behavior of AM materials when subjected to compression. The device is inexpensive and easy to implement in a quality assurance environment, being thus interesting for industrial applications.

Evaluation of Flowability of Wet Granular Materials by Stirring Torque: Effects of Additive Liquid Viscosity on Flowability

Evaluation of Flowability of Wet Granular Materials by Stirring Torque: Effects of Additive Liquid Viscosity on Flowability

Characterization of sugarcane bagasse ash (SBA) and its evaluation for use in alkali-activated slag mixtures

This work proposed to incorporate the sugarcane bagasse ash (SBA) with a high content of organic matter (loss on ignition of 35.87%) in alkali-activated mixtures with blast furnace slag. After grinding SBA, replacement ratios of 10%, 20%, and 30% of the ground ash were used for the flowability evaluation. The mixtures containing 20% and 30% showed a dry consistency, then only the mixture with 10% of slag was used for the other tests. The use of an air-entraining admixture led to an improvement in the flowability of the alkali-activated mixtures. X-ray diffraction results showed that both SBA and the air-entraining admixture did not interfere in the mineralogical composition of the hydrated products. However, the use of SBA led to a decrease in the compressive strength of about 20% to 28%. In conclusion, SBA proved to be viable for use in alkali-activated mixtures considering its effect on mechanical performance.

Evaluation of flowability for granulated powder using a test of powder discharge by pressurized air

This study experimentally and theoretically examined the flowability and the cohesiveness for powder using a test of powder discharge through an orifice by the pressurized air. The powder used consisted of two kinds of Calcium hydroxide which have different particle sizes by granulation. These sizes are 11µm and 176µm, those called Ca(OH)2 -A and -B. Cohesiveness is characterized by the Bond number which is the ratio of separation force to the gravity force. Flowability is evaluated by the relationship between the mass flow rate and the average air pressure acting on the powder bed. We found that the Bond number of Ca(OH)2 -B was much lower than Ca(OH)2 -A. The relation between the mass flow rate of the powder and the average air pressure indicates Ca(OH)2 -B is easily flowing at the lower pressure region, and Ca(OH)2 -A was scattered at the higher pressure region. This means Ca(OH)2 -B has good flowability by the particle granulation in comparison with Ca(OH)2 -A.

Flowability Evaluation of Higher Fluidization Treated Soils by Granules Analysis with Distinct Element Method

Flowability Evaluation of Higher Fluidization Treated Soils by Granules Analysis with Distinct Element Method

Testing and Evaluation of Flowability, Viscosity and Long-Term Compressive Strength of Cement Modified with Polymeric Admixture WR Superplasticizer

In this study, the effect of three types of powder polymer water reducer (WR) superplasticizer on the fluidity, rheological properties, density and mechanical properties of cement were investigated. The behavior of cement paste in the liquid phase and hardened phase modified with polymers up to 0.25% (by dry weight of cement) were studied. The amount of mixing water was reduced and varied between 20% - 58%. The Vipulanandan model was used to predict the water to cement ratio (w/c) of cement. The flowability, compressive strength, and density at different curing times were increased with increasing the polymer content. Three different brand of water reducer (WR) powder polymer increased the apparent viscosity of the cement paste; the viscosity was varied between 135 cP and 652 cP based on the type of polymer, polymer content, temperature, and water to cement ratio (w/c). Using of 0.25% of polymers to the cement increased the compressive strength of the cement paste by 127% to 426% based on the types of polymer, polymer content, and water to cement ratio (w/c) and curing time. Regression analysis was used to evaluate the effect of each polymer contents, w/c and curing time on the compressive strength of cement paste.

Controlled low-strength materials for pavement foundations in road tunnels: feasibility study and recommendations

This paper presents the results obtained during a laboratory and field investigation which focused on the assessment of the feasibility of using controlled low strength materials (CLSMs) in pavement foundations of road tunnels. The CLSM considered in the study, which contained a significant amount of recycled asphalt pavement, was designed by optimizing its flowability and by considering its sensitivity to changes in cement dosage. For comparative purposes, a standard low-strength Portland cement concrete mixture was also included in the investigation. Both mixtures were produced in a Portland cement concrete batching plant and were thereafter subjected to laboratory tests for the evaluation of flowability, consistency, compressive strength, California bearing ratio and resilient modulus. Furthermore, full-scale slabs constructed with the two mixtures were subjected to plate loading tests and to the transit of a fully-loaded heavy vehicle. Obtained results indicated that both mixtures are suitable for the formation of pavement foundations since they exhibit a short-term mechanical behavior which is comparable to that of standard granular sub-base materials. However, the CLSM proved to be superior in terms of its improved flowability, easier long-term excavatability, lower production cost and enhanced sustainability. Finally, recommendations for future applications of cement-bound materials in pavement foundations were provided in the form of preliminary performance-based acceptance criteria.

The Study about Strength Characteristic of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) with Fiber Combination

The ultra-high performance concrete (UHPC) has compressive strength over 100 MPa. The latest study about UHPC is reaching higher bending strength as well as higher compressive strength than conventional concrete. The typical method is the fiber reinforced concrete. The purpose of this study evaluated the fiber reinforced UHPC (UHPFRC) with single fibers and composite fibers which mixed with p-A (para-Aramid) fibers and other fibers. In the result of the slump flow test, the flow-ability with single fibers is more superior than the composite fibers. In the result of the compressive and bending strength, the specimens with the composite fibers that mixed the steel fibers and the p-A fibers are the highest strength. The authors were confirmed that the composite fibers had competitiveness compared with the single fibers through the flow-ability evaluation and the strength test.

Evaluation of flowability, pH and calcium ion release of high-plasticity cements

The aim of the study is to evaluate the physical and chemical properties of high plasticity calcium silicate-based cements (MTA HP, and MTA Flow) and to purpose a novel high plasticity cement composed of tricalcium and dicalcium silicate, bismuth oxide, zinc oxide and in the liquid, distilled water and water-soluble polymer. The association of zinc oxide in MTA Flow will be also evaluated to inhibit dental discoloration verified in a pilot test. The flowability, pH and calcium release will be evaluated.

A Review: Recent Progress on Evaluation of Flowability and Floodability of Powder

A Review: Recent Progress on Evaluation of Flowability and Floodability of Powder

The effect of magnesium stearate and sodium starch glycolate on powder flowability

The powder flow plays an important role in the manufacture of dosage form such as direct compression tablets. The objective of this research was to investigate the individual and interaction effects of magnesium stearate (MgSt) (Merck Ltd., Germany) as lubricant and sodium starch glycolate (SSG) (Primojel?) as superdesintegrator on powder flowability. Powder formulations were prepared by mixing different concentration of MgSt (0.25% and 5%) and SSG (0.5% and 4%) with microcrystalline cellulose (MCC) (Vivapur?101) or spray-dried lactose (LAC) (Super Tab 21AN) as diluents. Eight powder formulations were prepared using as filler LAC and MCC, as superdesintegrator SSG and as lubricant MgSt in ratios as follows: P1 (LAC : 0.5% SSG : 0.25% MgSt); P2 (LAC : 4% SSG : 5% MgSt); P3 (LAC : 0.5% SSG : 5% MgSt); P4 (LAC : 4% SSG : 5% MgSt); P5 (MCC : 0.5% SSG : 0.25% MgSt); P6 (MCC : 4% SSG : 5% MgSt); P7 (MCC : 0.5% SSG : 5% MgSt); P8 (MCC : 4% SSG : 0.25% MgSt). The powder formulations were evaluated using indirect methods of flowability evaluation according to 9th European Pharmacopoeia: measurement of tapped and bulk density (Ph.Eur.9, 2.9.34) and angle of repose (Ph.Eur. 2.9.36). Also, compressibility index, Hausner?s ratio were calculated. A full factorial design with three factors at two levels and response surface methodology were applied to evaluate the influence of various concentrations of MgSt and SSG on powder flowability. The results indicate that flow properties improved with decrease of SSG content and with increase of MgSt content. Magnesium stearate in powder formulations with microcrystalline cellulose has a greater influence on the improvement of the flow properties than powder formulations with spray-dried lactose.

Characterising powder flowability at high shear rates by the ball indentation method

Unreliable powder flow is a major problem during processing of powders. The shear cell is the most widely used method for powders subjected to moderate or high stresses, and under quasi-static conditions, with established methods for designing large bins and hoppers based on the measurement. However, this method is not suitable for measuring the flowability of dynamic systems, such as powder mixing.Here, the ball indentation method is investigated as a technique for evaluating powders in the intermediate and dynamic regime of flow. The method, which simply consists of dropping a ball onto a cylindrical bed of powder previously consolidated, directly measures hardness, which is related to the unconfined yield stress of the powder by the constrain factor (Hassanpour and Ghadiri, 2007). The impact of the ball on the bed is recorded with a high-speed camera to determine velocity and penetration depth. The shear rate is varied by using a range of indenter materials and sizes, and a range of drop heights. The hardness against the strain rate is considered for several materials.It was found that the indenter size does not influence the hardness results, which are consistent with the flowability evaluation achieved with the rheometer. Furthermore the hardness, which is independent of the strain rate in quasi-static conditions, becomes shear rate dependent in intermediate regime of flow. Further work is needed to evaluate hardness in the rapid granular flow regime.

Cohesive Force Determination and Flowability Evaluation of Pulverized Coal in Industrial Gasification Unit

Cohesive Force Determination and Flowability Evaluation of Pulverized Coal in Industrial Gasification Unit

空気流による噴出法を用いた付着性粉体の流動性の評価

空気流による噴出法を用いた付着性粉体の流動性の評価

加圧噴出法による付着性粉体の流動性と噴流性の評価

加圧噴出法による付着性粉体の流動性と噴流性の評価

空気流による噴出法を用いた付着性粉体の流動評価の研究

We investigated to the evaluation of flowability of cohesive powder using the test of powder discharge from an orifice by air flow. In this study, we used three kinds of Calcium hydroxide which changed the particle diameter. The mean particle diameter of an original powder, Ca(OH)2 A, is 13.1μm. Other particle diameters, i.e. Ca(OH)2 B and Ca(OH)2 C, are 14.1μm and 2.5μm respectively. As The experimental conditions, the initial void fraction and the interstitial air pressure have been changed. The result was obtained that the flowability of Ca(OH)2 B was the highest flow which was judged from the relation of the mass flow rate and the average interstitial air pressure. Furthermore, the influence of cohesiveness between particles was examined from the relationship between the ration of separation force to gravity force and the initial void fraction. The result indicated that the cohesiveness of Ca(OH)2 C which has the smallest particle diameter was the strongest.

空気流による噴出法を用いた付着性粉体の流動評価に関する研究

Evaluation of flowability of cohesive powder using the test of powder discharge from an orifice by air flow have been investigated. Three kinds of Calcium hydroxide was used in this study. As the experimental condition, the interstitial air pressure and the initial void fraction were varied. Judgement of the powder discharge was carried out to the continuous discharge and the change of interstitial air pressure. When the initial void fraction was decreased, the high pressure was needed to the beginning of powder discharge from an orifice because of the effect of increased cohesive force between particles. The difference in cohesive force of three powders could be indicated clearly from the relationship between the ration of estimated cohesive force to gravity force and the initial void fraction. As the result, it is supposed that the high flowability of powder was obtained when the ration of cohesive force to gravity force is small.