scholarly journals Powder properties of binary mixtures of chloroquine phosphate with lactose and dicalcium phosphate

2010 ◽  
Vol 46 (3) ◽  
pp. 531-537
Author(s):  
Michael Ayodele Odeniyi ◽  
Collins Chidi Onyenaka ◽  
Oludele Adelanwa Itiola
Keyword(s):  
Binary Mixtures ◽  
Internal Flow ◽  
Optical Microscope ◽  
Volume Reduction ◽  
Dicalcium Phosphate ◽  
Flow Properties ◽  
Maximum Volume ◽  
Cohesive Properties ◽  
Particle Size And Shape ◽  
The Individual

A study was conducted on the packing and cohesive properties of chloroquine phosphate in binary mixtures with lactose and dicalcium phosphate powders. The maximum volume reduction due to packing as expressed by the Kawakita constant, a, and the angle of internal flow, θ, were the assessment parameters. The individual powders were characterized for their particle size and shape using an optical microscope. Binary mixtures of various proportions of chloroquine phosphate with lactose and dicalcium phosphate powders were prepared. The bulk and tapped densities, angles of repose and internal flow, as well as compressibility index of the materials were determined using appropriate parameters. The calculated and determined values of maximum volume reduction for the binary mixtures were found to differ significantly (P< 0.05), with the Kawakita plot being more reliable in determining the packing properties. Diluent type was found to influence the flow properties of the mixtures, with dicalcium phosphate giving predictable results while mixtures containing lactose were anomalous with respect to flow. The characterization of the packing and cohesive properties of the binary mixtures of chloroquine with lactose and dicalcium phosphate would be useful in the production of powders, tablets, capsules and other drug delivery systems containing these powders with desirable and predictable flow properties.

Effect of the Compatibility of Rubbers on the Viscous Flow Properties of Their Binary Mixtures

1973 ◽  
Vol 46 (5) ◽  
pp. 1188-1192 ◽  
Author(s):  
G. S. Kongarov ◽  
G. M. Bartenev
Keyword(s):  
Strain Rate ◽  
Viscous Flow ◽  
Binary Mixtures ◽  
Binary Systems ◽  
Flow Properties ◽  
Entrance Effect ◽  
The Individual

Abstract The viscosity of binary systems of incompatible polymers is lower than that of the individual rubbers. In the case of compatible polymers, the viscosity of the systems changes additively with its composition or may increase somewhat. The degree of compatibility of the polymers affects the size of the entrance effect and the character of its dependence on strain rate.

scholarly journals Thermal and Photophysical Studies of Binary Mixtures of Liquid Crystal with Different Geometrical Mesogens

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 223 ◽  
Author(s):  
Omaima A. Alhaddad ◽  
Hoda A. Ahmed ◽  
Mohamed Hagar ◽  
Gamal R. Saad ◽  
Khulood A. Abu Al-Ola ◽  
...  
Keyword(s):  
Binary Mixtures ◽  
Density Functional ◽  
Binary Systems ◽  
Uv Spectroscopy ◽  
Twist Angle ◽  
Optical Microscope ◽  
Geometrical Parameters ◽  
Scanning Calorimetry ◽  
Photophysical Studies ◽  
The Individual

Three binary systems were prepared by mixing of two different mesogenic derivatives, homologues, the first is azo/ester, namely 4-alkoxyphenylazo-4′-phenyl-4″-alkoxybenzoates (IIn+m) and the second is Schiff base/ester, namely 4-(arylideneamino)phenyl-4″-alkoxy benzoates (In+m). The two corresponding analogues from both series in the binary mixtures investigated are of the same terminal alkoxy chain length. Mesomorphic properties were investigated by differential scanning calorimetry (DSC) and phases identified by polarized optical microscope (POM). Photophysical studies were investigated by UV spectroscopy connected to a hot stage. Results were discussed based on constructed binary phase diagrams. All mixtures were found to exhibit eutectic compositions, with linear or slightly linear nematic and smectic A stability/composition dependences. Geometrical parameters were predicted applying density functional theory (DFT) calculations. Twist angle (θ), aspect ratio, dipole moment and the polarizability of the individual compounds were discussed and correlated with the experimental results to illustrate the enhanced the mesophase stability and the mesophase range of the mixture at the eutectic composition compared with those of their individual components.

scholarly journals Ολοκληρωμένη συστοιχία αισθητήρων βασισμένη σε πολυμερή για την αναγνώριση πτητικών αερίων

2012 ◽  
Author(s):  
Πέτρος Οικονόμου
Keyword(s):  
Binary Mixtures ◽  
Sensor Array ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Principal Component ◽  
Polymeric Materials ◽  
Integrated Sensor ◽  
Electromagnetic Model ◽  
The Individual ◽  
Electronic Elements

In this research the sensor type of planar InterDigitated Capacitors (IDCs), also known as chemcapacitors, is demonstrated and its application in the detection of Volatile Organic Compounds (VOCs) and humidity is explored. The IDC layout configuration is studied by using a dedicated electromagnetic model and the behavior of different planar IDE structures/geometries coated with different polymeric materials of different dielectric permittivity values (εp) is determined. This study leads to the optimum design geometry of the planar IDCs that will be used for the detection of analytes. In order to identify the more suitable sensing materials for the targeted application, a methodology based on swelling measurements of the polymeric material upon exposure to analytes of interest was developed and applied in the prediction of the response of a chemcapacitor upon exposure to different VOCs. The integrated sensor array is characterized by the responses of each sensor to exposure to several pure analytes, binary mixtures of analytes and complex environments. Several parameters were examined such as sensitivity, selectivity, limit of detection, aging. Also the total response of the sensor array is analyzed by conjunction of the individual responses of each sensor and the use of suitable Principal Component Analysis, PCA, models that have been developed. Fabrication of a hybrid low-power gas sensing module is presented. This module is realized with integration on the same device of the sensor array with the appropriate electronic elements. The latter provide the power, control and read-out electronics of the output signal. The proposed hybrid micro-device is characterized in terms of the response of each sensor of the sensor array upon exposure to different pure analytes and their binary mixtures. Evaluation of the results obtained by the characterization of the hybrid gas sensing module demonstrate the ability of use such a device in analytical methods under conditions of constant or alterable concentration of VOCs/humidity or their mixtures in applications either at constant temperature or at temperature changing over time simulating that way real time applications.

scholarly journals 316L Stainless Steel Powders for Additive Manufacturing: Relationships of Powder Rheology, Size, Size Distribution to Part Properties

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5537
Author(s):  
Robert Groarke ◽  
Cyril Danilenkoff ◽  
Sara Karam ◽  
Eanna McCarthy ◽  
Bastien Michel ◽  
...  
Keyword(s):  
Particle Size ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Optical Microscope ◽  
Stainless Steel 316L ◽  
Powder Morphology ◽  
Size And Shape ◽  
Powder Rheology ◽  
Powder Properties ◽  
Particle Size And Shape

Laser-Powder Bed Fusion (L-PBF) of metallic parts is a highly multivariate process. An understanding of powder feedstock properties is critical to ensure part quality. In this paper, a detailed examination of two commercial stainless steel 316L powders produced using the gas atomization process is presented. In particular, the effects of the powder properties (particle size and shape) on the powder rheology were examined. The results presented suggest that the powder properties strongly influence the powder rheology and are important factors in the selection of suitable powder for use in an additive manufacturing (AM) process. Both of the powders exhibited a strong correlation between the particle size and shape parameters and the powder rheology. Optical microscope images of melt pools of parts printed using the powders in an L-PBF machine are presented, which demonstrated further the significance of the powder morphology parameters on resulting part microstructures.

scholarly journals Viscosity sinergism of hydrozypropmethyl and carboxy methyl cellulose

2008 ◽  
Vol 62 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Jaroslav Katona ◽  
Verica Sovilj ◽  
Lidija Petrovic
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Binary Mixtures ◽  
Methyl Cellulose ◽  
Mass Ratio ◽  
Positive Deviation ◽  
Flow Properties ◽  
Concentration Changes ◽  
Overlap Concentration ◽  
Carboxy Methyl

Rheology modifiers are common constituents of food, cosmetic and pharmaceutic products. Often, by using two or more of them, better control of the product rheological properties can be achieved. In this work, rheological properties of hydroxypropymethyl cellulose (HPMC) and sodium carboxymethyl cellulose (NaCMC) solutions of different concentrations were investigated and compared to the flow properties of 1% HPMC/NaCMC binary mixtures at various HPMC/NaCMC mass ratios. Solutions of HPMC and NaCMC were found to be pseudoplastic, where pseudoplasticity increases with increase in the macromolecules concentration. Changes of the degree of pseudoplasticity, n as well as the coefficient of consistency, K with the concentration are more pronounced in HPMC solutions when compared to the NaCMC ones. This is mostly due to the ability of HPMC molecules to associate with each other at concentrations above critical overlap concentration, c , and greater flexibility of macromolecular chains. Binary mixtures of HPMC/NaCMC were also found to be pseudoplastic. Experimentally obtained viscosities of the mixture were proved to be larger than theoretically expected ones, indicating viscosity synergism as a consequence of HPMC-NaCMC interaction. Maximum in synergy was observed when HPMC/NaCMC mass ratio was 0.4/0.6, no matter of the shear rate applied. On the other hand, it was found that relative positive deviation, RPD decreases when shear rate is increased.

scholarly journals Challenging a bioinformatic tool’s ability to detect microbial contaminants usingin silicowhole genome sequencing data

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3729 ◽  
Author(s):  
Nathan D. Olson ◽  
Justin M. Zook ◽  
Jayne B. Morrow ◽  
Nancy J. Lin
Keyword(s):  
Binary Mixtures ◽  
Genome Sequencing ◽  
Pathogen Detection ◽  
A Priori ◽  
High Sensitivity ◽  
False Positives ◽  
Sequencing Data ◽  
Materials Used ◽  
The Individual ◽  
Genome Assemblies

High sensitivity methods such as next generation sequencing and polymerase chain reaction (PCR) are adversely impacted by organismal and DNA contaminants. Current methods for detecting contaminants in microbial materials (genomic DNA and cultures) are not sensitive enough and require either a known or culturable contaminant. Whole genome sequencing (WGS) is a promising approach for detecting contaminants due to its sensitivity and lack of need fora prioriassumptions about the contaminant. Prior to applying WGS, we must first understand its limitations for detecting contaminants and potential for false positives. Herein we demonstrate and characterize a WGS-based approach to detect organismal contaminants using an existing metagenomic taxonomic classification algorithm. Simulated WGS datasets from ten genera as individuals and binary mixtures of eight organisms at varying ratios were analyzed to evaluate the role of contaminant concentration and taxonomy on detection. For the individual genomes the false positive contaminants reported depended on the genus, withStaphylococcus,Escherichia, andShigellahaving the highest proportion of false positives. For nearly all binary mixtures the contaminant was detected in thein-silicodatasets at the equivalent of 1 in 1,000 cells, thoughF. tularensiswas not detected in any of the simulated contaminant mixtures andY. pestiswas only detected at the equivalent of one in 10 cells. Once a WGS method for detecting contaminants is characterized, it can be applied to evaluate microbial material purity, in efforts to ensure that contaminants are characterized in microbial materials used to validate pathogen detection assays, generate genome assemblies for database submission, and benchmark sequencing methods.

scholarly journals Assessment of wood microstructural changes after one-stage thermo-hydro treatment (THT) by micro X-ray computed tomography

Holzforschung ◽  
2016 ◽  
Vol 70 (2) ◽  
pp. 167-177 ◽  
Author(s):  
Vladimirs Biziks ◽  
Jan Van den Bulcke ◽  
Juris Grinins ◽  
Holger Militz ◽  
Bruno Andersons ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cell Types ◽  
Volume Reduction ◽  
Fiber Volume ◽  
Microstructural Changes ◽  
X Ray ◽  
Lumen Volume ◽  
Before And After ◽  
X Ray Computed ◽  
The Individual

AbstractThe microstructural changes in a selection of softwoods and hardwoods resulting from thermo-hydro treatment (THT) at 160°C were examined by means of a state-of-the-art micro X-ray computed tomography. A dedicated X-ray scanning and volumetric processing protocol was developed. All reconstructed volumes had an approximate voxel pitch between 0.8 and 1.2 μm3. The microstructures of the same needle-shaped specimens before and after THT were visualized, and the individual parameters (maximum opening and lumen volume) for various cell types were quantified and compared. The highest values of substance volume were recorded for the ash sapwood (81%) and spruce specimens (72%). After THT, a significant correlation was found between the mass loss determined by gravimetry and the X-ray volume loss. The largest change occurred in the lumen volume of several tissue components, such as libriform fibers, tracheids, and ray parenchyma. The average aspen fiber volume reduction after THT was 31%, a value 2.6 times higher than the volume reduction of the average vessels. The porosity of ash sapwood increased from 41 to 56%, whereas the porosity of birch decreased from 34 to 29%.

INDUCED INFRARED ABSORPTION OF DEUTERIUM IN DEUTERIUM – FOREIGN GAS MIXTURES

1966 ◽  
Vol 44 (11) ◽  
pp. 2893-2903 ◽  
Author(s):  
S. T. Pai ◽  
S. Paddi Reddy ◽  
C. W. Cho
Keyword(s):  
Absorption Band ◽  
Binary Mixtures ◽  
Infrared Absorption ◽  
Room Temperature ◽  
The Other ◽  
Absorption Profile ◽  
Absorption Coefficients ◽  
Helium Mixtures ◽  
Experimental Values ◽  
The Individual

The pressure-induced fundamental infrared absorption band of deuterium was studied in deuterium–helium, deuterium–argon, and deuterium–nitrogen mixtures at pressures up to 1 200 atm at room temperature. The enhancement absorption profile of each mixture shows a well-resolved splitting of the Q branch into two components QP and QR. While the enhancement contours of deuterium–helium mixtures do not exhibit any absorption peaks corresponding to the O and S branches, those of the other two binary mixtures show a pronounced S(2) peak and an indication of several other O and S peaks of the band. Integrated absorption coefficients of the band have been measured for all the mixtures, and the binary and ternary absorption coefficients were determined. The theory of Van Kranendonk and the available molecular parameters of deuterium and the perturbing gases were used to calculate the binary absorption coefficients of the individual lines of the O and S branches and of the quadrupole part of the Q branch of the band in all three binary mixtures. Using these calculated values and the experimental values of the total binary absorption coefficients of these mixtures, the overlap parts of the binary absorption coefficients of the Q branch were estimated.

THE RHEOLOGICAL PROPERTIES OF SOME SOAP–OIL SYSTEMS

1951 ◽  
Vol 29 (11) ◽  
pp. 996-1009 ◽  
Author(s):  
G. B. Moses ◽  
I. E. Puddington
Keyword(s):  
Rheological Properties ◽  
Solid Phase ◽  
Viscosity Data ◽  
Flow Properties ◽  
Abrupt Changes ◽  
Theoretical Predictions ◽  
The Individual

The flow properties of dispersions of sodium, lithium, and aluminum soaps in hydrocarbon oils have been measured over a range of temperature, concentration, and rate of shear using an extrusion plastometer. The variations of residual viscosity and coefficient of thixotropy, with temperature, are similar for all of these soaps. Abrupt changes occur at temperatures that are characteristic of the individual soaps. The variation of thixotropy with concentration is in accord with theoretical predictions, and axial ratios of the solid phase particles, calculated from viscosity data, are in agreement with observed values.

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