scholarly journals Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 23 ◽  
Author(s):  
Mahmoud E. Awad ◽  
Alberto López-Galindo ◽  
Djordje Medarević ◽  
Jelena Đuriš ◽  
Mahmoud M. El-Rahmany ◽  
...  
Keyword(s):  
Moisture Content ◽  
Elastic Recovery ◽  
Flow Characteristics ◽  
Total Pore Volume ◽  
Tensile Fracture ◽  
Strongly Correlated ◽  
Hausner Ratio ◽  
Content Variable ◽  
Disorder Degree ◽  
Tapped Density

The present work aimed at assessing the pharmaceutical tableting properties of some Egyptian kaolin samples belong to the Abu Zenima kaolin deposits (estimated at 120 million tons). Four representative samples were selected based on kaolinite richness and their structural order-disorder degree, and after purification, they were dried at 70 °C and heated from room temperature up to 400 °C (10 °C/min). Mineralogy, micromorphology, microtexture, granulometry, porosimetry, moisture content, bulk and tapped density, direct and indirect flowability, and tableting characteristics are studied. Results indicated that purified kaolin samples were made up of 95–99% kaolinite, <3% illite, 1% quartz and 1% anatase. The powder showed mesoporous character (pore diameters from 2 to 38 nm and total pore volume from 0.064 to 0.136 cm3/g) with dominance of fine nanosized particles (<1 μm–10 nm). The powder flow characteristics of both the ordered (Hinckley Index HI > 0.7, crystallite size D001 > 30 nm) and disordered (HI < 0.7, D001 < 30 nm) kaolinite-rich samples have been improved (Hausner ratio between 1.24 and 1.09) as their densities were influenced by thermal treatment (with some observed changes in the kaolinite XRD reflection profiles) and by moisture content (variable between 2.98% and 5.82%). The obtained tablets exhibited hardness between 33 and 44 N only from the dehydrated powders at 400 °C, with elastic recovery (ER) between 21.74% and 25.61%, ejection stress (ES) between 7.85 and 11.45 MPa and tensile fracture stress (TFS) between 1.85 and 2.32 MPa, which are strongly correlated with crystallinity (HI) and flowability (HR) parameters. These findings on quality indicators showed the promising pharmaceutical tabletability of the studied Egyptian kaolin powders and the optimization factors for their manufacturability and compactability.

scholarly journals Tensile response and fracturing process in moderate- and high-plasticity clays

2020 ◽  
pp. 1-11
Author(s):  
Giulia Forlati ◽  
Paul Shepley
Keyword(s):  
Moisture Content ◽  
Fracture Behaviour ◽  
Soil Layer ◽  
Clay Soils ◽  
Tensile Fracture ◽  
Future Research ◽  
High Plasticity ◽  
Bending Tests ◽  
Fracturing Process ◽  
The Difference

Sinkholes in clay soils can be considered as the collapse of a soil layer previously bridging a void. Here, flexural deformation in the clay drives the formation of tensile cracks from the lowest surface of the layer and the consequent soil collapse is from crack propagation. Considering a simplified model of the sinkhole geometry, this paper aims to describe the tensile and fracture behaviour of clay soils with different plasticity indices. Speswhite kaolin, London, and Durham clays were tested using direct tensile and bending tests. Moderate- and high-plasticity clays showed a nonlinear fracture response with increasing moisture content, while low-plasticity clays demonstrated a linear response. Bending tests confirmed the importance of the moisture content while the plasticity index confirmed the difference in ductile or fragile collapse for fracture propagation. To assess the results, elasto-plastic fracture mechanics (EPFM) theory was applied to clays with appropriate modifications. The analysis demonstrated that EPFM theory provides a good baseline for predicting tensile fracture behaviour in clay soils, which can be extended in future research.

Moisture Dependent Dynamic Flow Properties of Coconut Flours

2016 ◽  
Vol 12 (6) ◽  
pp. 577-585 ◽  
Author(s):  
M. R. Manikantan ◽  
R. P. Kingsly Ambrose ◽  
Sajid Alavi
Keyword(s):  
Moisture Content ◽  
Normal Stress ◽  
Flow Characteristics ◽  
Coconut Oil ◽  
Friction Angle ◽  
Wall Friction ◽  
Flow Properties ◽  
Dynamic Flow ◽  
Virgin Coconut Oil ◽  
Air Velocity

Abstract The dynamic flow properties of two important coproducts of virgin coconut oil (VCO) i. e. coconut milk residue flour (MRF) and VCO cake flour (CF) were studied. The basic flowability energy of CF was higher than MRF and increased with moisture content. The change in compressibility and shear stress, with applied normal stress and moisture content, indicated that these powders are highly cohesive. For both flours, the energy required to make the powder flow increased with moisture at all experimental air velocity. Moisture did not significantly influence the cohesion and unconfined yield strength of MRF, whereas for CF there was significant effect due to the presence of moisture. The wall friction angle of both the flours increased significantly with moisture and decreased with applied normal stress. The results from this study indicated that, both CF and MRF at around 4.00 % moisture content had better flow characteristics than at higher moisture levels.

Seasonal changes in diatom biomass, sediment stability and biogenic stabilization in the Severn Estuary

1993 ◽  
Vol 73 (4) ◽  
pp. 871-887 ◽  
Author(s):  
Graham J. C. Underwood ◽  
David M. Paterson
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Surface Sediments ◽  
Critical Shear Stress ◽  
Strongly Correlated ◽  
Sediment Stability ◽  
Severn Estuary ◽  
Epipelic Diatoms ◽  
The Stability ◽  
Better Than

Epipelic diatoms represented the dominant microphy tobenthos on the intertidal mudflats of the Severn Estuary, south-western Britain. Algal biomass (measured as chlorophyllaconcentration) varied over a seasonal cycle and was strongly correlated with sediment shear strength and critical shear stress and therefore with position on the shore. High levels of diatom biomass were positively correlated with the concentration of colloidal carbohydrate within the surface sediments. The critical shear strength for incipient erosion was significantly correlated with position on the shore (moisture content) and with both chlorophyllaand colloidal carbohydrate, the latter being the best biochemical predictor for the incipient erosion threshold. The range of stress required to cause incipient erosion varied from 1.0 to 8.0 N m-2, with the sediment increasing in resistance landwards. Two-way analysis of variance using both moisture content and colloidal carbohydrate as variables explained the stability of the sediment better than individual pair-wise comparisons.

scholarly journals Preformulation Study of Pugun Tano (Curanga fel-terrae [Lour.] Merr) Ethanolic Extract Granule Mass in Capsule as Hepatoprotective Drug

2019 ◽  
Vol 7 (22) ◽  
pp. 3729-3732
Author(s):  
Urip Harahap ◽  
Marianne Marianne ◽  
Yuandani Yuandani ◽  
Lia Laila
Keyword(s):  
Bulk Density ◽  
Dosage Form ◽  
Corn Starch ◽  
Ethanolic Extract ◽  
Magnesium Stearate ◽  
Angle Of Repose ◽  
Wet Granulation ◽  
Hausner Ratio ◽  
Tapped Density ◽  
Preformulation Study

BACKGROUND: Pugun tano extract had been studied for its effect as hepatoprotector. However, the usage of the plant in the form of extract has a limitation, especially if the extract is consumed by the people due to the unpleasant taste and odour. Then, the extract needs to be transformed into a particular dosage form, such as a capsule. But before the capsule can be produced, a preformulation study of pugun tano extract into a granule mass in capsule need to be evaluated. AIM: The study aimed to formulate the ethanolic extract of pugun tano (Curanga fel-terrae (Lour.) Merr) as granule mass in the capsule dosage form. METHODS: The pugun tano ethanolic extract was formulated in several steps included preparation of dry extract using coating method with polyvinylpyrrolidone (PVP) and granule mass production. The excipients used for the granule mass were lactose granules (made with tapioca starch using wet granulation), corn starch (made with 3 concentrations of 5% (F1), 7.5% (F2) and 10% (F3)), talcum, magnesium stearate, methylparaben, and propylparaben. The granule mass was evaluated for the bulk density, tapped density, inter-particle porosity, Carr’s index, Hausner ratio, angle of repose, and flowability. RESULTS: The results showed that all of the formulae passed the requirement of the preformulation test. The bulk density of the granule mass was 0.79 – 0.86 g/ml; the tapped density was 0.88 – 0.90 g/ml; the inter-particle porosity was 0.03 – 0.14; the Carr’s index was 2.71 – 11.94%; the Hausner ratio was 1.09-1.12; the angle of repose was 26.10 – 28.90°; and the flowing time was 5.97 – 6.63 seconds. All of the formulae showed good flowability and free-flowing properties. CONCLUSION: It is concluded that the obtained formula

scholarly journals FORMULATION AND EVALUATION OF METRONIDAZOLE TABLETS USING NATURAL GUM

2019 ◽  
pp. 304-306
Author(s):  
SUDIPTA DAS ◽  
SOUMITRA DAS
Keyword(s):  
Aloe Vera ◽  
Angle Of Repose ◽  
In Vitro Dissolution ◽  
Binding Agent ◽  
Binding Properties ◽  
Disintegration Time ◽  
Hausner Ratio ◽  
Percentage Release ◽  
Tapped Density

Objectives: The objective of the present study was to formulate the metronidazole tablets using natural Aloe vera gum as binding agent. Materials and Methods: To determine the binding properties of the extracted A. vera gum were used for the preparation of metronidazole tablets and compared with other binding agents such as acacia and sodium carboxymethyl cellulose (CMC). Physical properties such as hardness, friability, disintegration time, and in vitro dissolution rate are the important parameter which determines for each formulation. Three batches of metronidazole tablets are prepared using acacia (F1), sodium CMC (F2), and A. vera gum (F3) as binding agent. Results: The granules were evaluated by determining the angle of repose (26.01 ± 0.110–27.18 ± 0.166°), bulk density, tapped density, Hausner ratio, and Carr’s index. It shows satisfactory results. At time 90 min, the percentage release of drug for F1, F2, and F3 was 44.947%, 31.467%, and 53.424%, respectively. The tablets prepared with A. vera gum showed faster release profile than other binders. Conclusion: From the results, it was shown that tablets prepared with A. vera gum have good binding properties and also helped tablets for faster release.

scholarly journals Controlling Rice Leaf Breaking Force by Temperature and Moisture Content to Reduce Breakage

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 628
Author(s):  
Zhong Tang ◽  
Yu Li ◽  
Ben Zhang ◽  
Meilin Wang ◽  
Yaoming Li
Keyword(s):  
Moisture Content ◽  
Temperature Change ◽  
Fracture Resistance ◽  
Tensile Fracture ◽  
Rice Grain ◽  
Breaking Force ◽  
Cleaning Efficiency ◽  
Rice Leaf ◽  
Different Temperatures ◽  
Separation Force

Leaf fragments and grain mixture produced by rice threshing with a combine harvester seriously affects the subsequent grain cleaning efficiency. In this paper, rice leaf breaking force was tested at different temperatures and moisture contents to analyze the influence of temperature on the tensile properties of rice leaves. The overlapping regions of rice leaf breaking force and grain separation force at different temperatures were obtained. Based on the rice leaf breaking force, the effect of the temperature change on rice leaf with different moisture content was analyzed. The results showed that tensile strength of rice leaf decreased first, then increased and finally decreased from rice sheath to the top. The tensile breaking force of the leaf sheath was about 75 N (N is Newton, 1 N = 1 kg·m/s²). The tensile fracture resistance of rice leaf was shown to weaken with the increase of temperature. The influence of the moisture content on the mechanical properties of rice leaf during the process of temperature change was small. At 30 to 35 °C, the blade was the strongest tensile fracture resistance, which was the lowest probability of fracture under the same stress condition. At this time, the rice grain separation force has the least coincidence with the rice leaf resistance to breakage. According to the breaking force of different blade layers, the number of blade layers has a significant linear relationship with its tensile limit. Therefore, the overall fracture resistance of the multilayer blade can be improved by controlling the temperature and moisture content.

scholarly journals The influence factors for gas adsorption with different ranks of coals

2017 ◽  
Vol 36 (3-4) ◽  
pp. 904-918 ◽  
Author(s):  
Deyong Guo ◽  
Xiaojie Guo
Keyword(s):  
Moisture Content ◽  
Specific Surface ◽  
Pore Structure ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Gas Adsorption ◽  
Total Pore Volume ◽  
Factors Influencing

In this paper, scanning electron microscopy, low-temperature N2 adsorption and CH4 isothermal adsorption experiments were performed on 11 coal samples with Ro,max between 0.98 and 3.07%. The pore structure characteristics of coals (specific surface area, total volume distribution) were studied to assess the gas adsorption capacity. The results indicate that there is significant heterogeneity on coal surface, containing numerous channel-like pores, bottle-shaped pores and wedge-shaped pores. Both Langmuir volume (VL) and Langmuir pressure (PL) show a stage change trend with the increase of coalification degree. For different coalification stages, there exist different factors influencing the VL and PL values. For low-rank coals (Ro,max < 1.1%), the increase of VL values and decrease of PL values are mainly due to the abundant primary pore and fracture within coal. For middle-rank coals (1.1% < Ro,max < 2.1%), the moisture content, vitrinite content and total pore volume are all the factors influencing VL, and the reduction of PL is mainly attributed to the decrease of moisture content and inertinite content. Meanwhile, this result is also closely related to the pore shape. For high-rank coals (Ro,max > 2.1%), VL values gradually increase and reach the maximum. When the coal has evolved into anthracite, liquid hydrocarbon within pore begins pyrolysis and gradually disappears, and a large number of macropores are converted into micropores, leading to the increase of specific surface area and total pore volume, corresponding to the increase of VL. In addition, the increase of vitrinite content within coal also contributes to the increase of VL. PL, reaches the minimum, indicating that the adsorption rate reaches the largest at the low pressure stage. The result is mainly controlled by the specific surface area and total pore volume of coal samples. This research results will provide a clearer insight into the relationship between adsorption parameters and coal rank, moisture content, maceral composition and pore structure, and it is of great significance for better assessing the gas adsorption capacity.

Effect of Maltodextrin on Physical Properties of Granulated Xanthan Gum Prepared by Fluidized-Bed Granulator

2017 ◽  
Vol 13 (8) ◽  
Author(s):  
Yong-Hwan Kim ◽  
Sung-Gun Kim ◽  
Byoungseung Yoo
Keyword(s):  
Physical Properties ◽  
Fluidized Bed ◽  
Xanthan Gum ◽  
Loss Modulus ◽  
Flow Characteristics ◽  
Flow Properties ◽  
Main Ingredient ◽  
Granulation Process ◽  
Hausner Ratio ◽  
Tan Δ

AbstractFluidized-bed granulation has received considerable attention within the food process industry because granulated products often have improved flowability and appearance, and sometimes have specifically enhanced physical properties. In this study, the rheological properties of granulated xanthan gum (XG), commonly used as a main ingredient in food thickeners for dysphagia diets, were investigated at different concentrations (0, 5, 10, and 15 % w/w) of maltodextrin (MD) as a binder at different concentrations. Flowability and cohesiveness of granulated XG powder was also evaluated in terms of as Carr index (CI) and Hausner ratio (HR) were also investigated. The consistency index, apparent viscosity, storage modulus (G’) and loss modulus (G”) of granulated XG were significantly higher than those of non-granulated XG and granulated XG without binder (0 % MD). The tan δ values of granulated samples were lower compared with that of a non-granulated sample, indicating that their elastic properties were more pronounced because of the granulation. These rheological results also showed that there were no noticeable changes in flow properties between 0 % and 5 % MD concentrations, whereas the G’ and G” values at 10 % MD were much higher than those at other concentrations. The granulation process by MD binder also enhanced considerably flow characteristics of XG powder.

Sign in / Sign up

Export Citation Format

Share Document