China
Africa
Explore chapters and articles related to this topic
Parenteral Product Specifications and Stability
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Michael Bergren, Nanda Subbarao
ICHQ6A recommends “acceptance criteria should be set based on the observed ranges of variation and should take into account the dissolution profiles of the batches that showed acceptable performance in vivo and the intended use of the product.” While it would be uncommon to include acceptance criteria for particle size in specifications for early clinical batches, the measurement of particle sizes at this stage would provide important data for subsequent justification of acceptance criteria. In some cases, specific clinical studies may need to be designed to establish the limits of an acceptable range of particle sizes. Particle size must be assessed during stability studies since it is a stability-indicating attribute. The particle size distribution may change through dissolution and regrowth or through aggregation/agglomeration.
Particle Management
Published in Debasish Sarkar, Ceramic Processing, 2019
Particle size distribution is statistical data representing the relative amount of mass or volume of particles present corresponding to the respective size or range of size or in other words, it is the quantity of material in terms of the function of size. Various types of distribution can be represented, subject to property used as a basis for measurement. Particle size analysis is typically assessed in terms of the quantity of individual particles and the quantity of particles in each pre-determined size fraction is used to obtain the particle size distribution [41]. Prior to a discussion of such particle size distribution analysis, one can pick up the different characterization protocols, apart from sieve analysis, used to collect the particle size data (see Table 2.4).
Bulk Solids: Properties and Characterization
Published in Enrique Ortega-Rivas, Unit Operations of Particulate Solids, 2016
Particle size distribution measurement is a common method in any physical, mechanical, or chemical process because it is directly related to material behavior and/or physical properties of products. The bulk density, compressibility, and flowability of an industrial powder are highly dependent on particle size and its distribution. Segregation will take place in a free-flowing powder mixture because of the differences in particle sizes. There are many other properties of particulate systems that strongly depend on particle size, for example, activity of drugs, setting time of cement, and hiding power of pigments. Characterization of solid particles, which are in practice mostly irregular in shape, is usually done by analyzing particle size and its distribution. Other characteristic properties of the solid material may be included in the type of size measured; for example, Stoke’s diameter combines size, density, and shape all in one parameter. Quantitative measure of particle shape can be obtained indirectly by analyzing two or more types of particle size and looking at different “shape coefficients” that relate to those sizes. There are many different types of instruments available for measuring particle size distribution but most of them would fall into four general methods: sieving, microscope counting techniques, sedimentation, and stream scanning.
Experimental study to reduce the emission of carbon dioxide from cement plants: a case study on Asiabar local mineral pozzolan
Published in European Journal of Environmental and Civil Engineering, 2023
Mojtaba Rangrazian, Reza Mahjoub, Rahmat Madandoust, Mehdi Raftari
The particle size distribution is a mathematical function that usually expresses the mass of particles in terms of their size. The Asiabar pozzolan is a soft pozzolan that can physically fill the pores and cavities between cement grains to create a higher relative density for the concrete. Based on the measured results, the specific surface area of ordinary Portland cement and natural Asiabar pozzolan was equal to 0.35 and 1.23 m2/gr, respectively. Also, the average particle sizes of ordinary Portland cement and Asiabar pozzolans were measured as 9.34 μm and 3.55 μm, respectively. According to laboratory reports, the size of natural pozzolans’ particles is better than that of ordinary Portland cement. Some superplasticiser (M110 carboxylic) with a density of 1.03 g/cm3 (at 20 °C) was added to each mortar mixture aimed at increasing the flowability of the mixture and helping disperse the particles.
Experimental investigation on filtration characteristic with different filter material of bag dust collector for dust removal
Published in International Journal of Coal Preparation and Utilization, 2022
Xi Chen, Yanjun Mao, Chaonan Fan, Yucheng Wu, Shaocheng Ge, Yi Ren
The particulate matters used in this experiment were taken from Datang International Xilinhot Mining Company Coal Mine, and the bulk coal was processed into pulverized coal with different particle sizes less than 48 μm by crushing and sieving. The particle size distribution of was measured by laser diffraction particle size analyzer (Mastersizer 2000). According to the requirements, add an appropriate amount of purified water, use a concrete curing box with constant temperature and humidity, set the temperature to room temperature and the humidity to 6%, turn and vibrate every 2 hours, and cure for 24 hours to prepare a pulverized coal sample with a moisture content of 6%. Then, separate the pulverized coal according to the particle size with a sieve with different pore sizes. It is divided into 48 > d ≥ 38 μm, 38 > d ≥ 25 μm, 25 > d ≥ 23 μm, 23 > d ≥ 18 μm, 18 > d ≥ 13 μm, 13 > d ≥ 10 μm, 10 > d ≥ 6.5 μm, 6.5 > d ≥ 2.6 μm, 2.6 > d ≥ 1.6 μm, d < 1.6 μm and a total of ten granularities, where d is the particle size of pulverized coal. Weigh several grams of dust of each particle size with an electronic balance, put it in a sealed bag and label it. As shown in Figure 2.
Friction and Wear Behavior of Graphene and Graphite Oxide–Reinforced Epoxy Composites
Published in Tribology Transactions, 2022
Karthik Srinivas Venkataraman, Albert E. Segall, Koki Urita, Cira Feeney, Ron Sherant, Chiharu Urita, Ben Madden, Matthew Krohn, Fernando Vallejos-Burgos
Sanning electron microscopy (SEM) was used for morphological imaging of the samples. Initialy, the graphene particles were loaded on a double-sided carbon tape centered on the stub using a small spatula; an air gun was used to disperse the particles not adhered to the surface. SEM images were then taken at different accelerating voltages ranging from 1 to 20 keV. Brinell hardness values were obtained using a stainless steel ball of 1 mm diameter and a load range from 2.5 to 30 kg. Particle size distribution was measured using a laser diffraction particle size analyzer. Measurements were made using both red (633 nm) and blue light laser (470 nm) sources to cover particle sizes ranging from 10 nm to 3.5 mm. All measurements were carried out in five replicates and the average value of the five was reported. The Raman spectra of the samples were measured using a 532-nm laser with 600 gratings/mm and an incident power of 4.1 mW to obtain insights on the fillers. Fourier transform infrared (FTIR) measurements were made on a infrared microscope attached to a spectrometer. Measurements were made in attentuated total reflectance geometry using a Ge attenuated total reflection objective with a 100-μm-diameter tip. A total of 500 scans were averaged per spectrum and absorbance was calculated by referencing to a clean bare Ge tip.