Powder performance characterization

Powder X-Ray diffraction was employed to identify the crystalline phase of the prepared powder samples. Rietveld refinement was then performed on the XRD data to obtain the lattice constants. The electrochemical properties of LiCo,YyMn2 x.y04 powders were characterized in Li/LiCo,.YyMn2.,..y04 cells. The working electrodes were prepared by mixing polyvinylidene fluoride(PVDF), carbon black and LiCo,YyMn2.x.y04 powders in the ratio of 8 12 80% w/w, respectively. Electrochemical measurements were performed using lithium metal as counter and reference electrodes. The electrolyte was 1. OM anhydrous LiC104 dissolved in a 1 1 v/v ethylene carbonate and dimethyl carbonate mixture. The cell was cycled at a current rate of 0.2C between 3.6 and 4.3V, unless otherwise specified. 

LSM, SEKZ and LSCF powders were characterized by XRD using a Shimadzu XDR-7000 diffractometer and scanning electron microscopy (SEM-SSX 550, Shimadzu). Infrared spectra were also recorded with FTIR (IR Prestige-21, Shimadzu) in the 400 - 4600 cm"i spectral range. Specific surface area measurements were performed only for the LSM powders. An infrared reflectance spectrum of a LSM pellet prepared from a powder calcined at 900 °C was recorded with a Fourier-transform spectrometer (Bomem DA 8-02) equipped with a fixed-angle specular reflectance accessory (external incidence angle of 11.5°). 

A comparative study of the spray-dried nanoparticulate budesonide versus micronized budesonide was performed Each powder was blended with lactose and then filled into a Clickhaler (ML Laboratories) DPL and the aerodynamic diameters of the dehvered powders were characterized on an Andersen eight-stage cascade impactor. The results, which are summarized grcq)hically in the following section, show that the MMAD of the nanoparticulate aggregate aerosol was much smaller than the MMAD of the micronized drug aerosol. A substantial fraction of... 

The CuCr02 powders were characterized using various techniques The crystalline phase analysis of the powders was performed using an X-ray diffractometer (XRD) (Bruker, D2) with Cu K radiation ( l = 1.540 A). A scanning electron microscope (SEM) (Hitachi, S-4700) was used to determine the morphology and the state of agglomerates in the powder. The BET (Micrometries ASAP2010) method was applied to measure the surface area. 

Analysis. Excellent reviews of phosphate analysis are available (28). SoHds characterization methods such as x-ray powder diffraction (xrd) and thermal gravimetric analysis (tga) are used for the identification of individual crystalline phosphates, either alone or in mixtures. These techniques, along with elemental analysis and phosphate species deterrnination, are used to identify unknown phosphates and their mixtures. Particle size analysis, surface area, microscopy, and other standard soHds characterizations are useful in relating soHds properties to performance. SoHd-state nmr is used with increasing frequency. 

In the second part of the 20th century, the tantalum capacitor industry became a major consumer of tantalum powder. Electrochemically produced tantalum powder, which is characterized by an inconsistent dendrite structure, does not meet the requirements of the tantalum capacitor industry and thus has never been used for this purpose. This is the reason that current production of tantalum powder is performed by sodium reduction of potassium fluorotantalate from molten systems that also contain alkali metal halides. The development of electronics that require smaller sizes and higher capacitances drove the tantalum powder industry to the production of purer and finer powder providing a higher specific charge — CV per gram. This trend initiated the vigorous and rapid development of a sodium reduction process. 

Burford, R.P. and Pittolo, M., Characterization and performance of powdered ruhher, Rubber Chem. 

The boron nitride obtained in this study was characterized by infrared spectroscopy, powder x-ray diffractometry and transmission electron microscopy. Trace elemental analyses were also performed by energy dispersive x-ray analysis and carbon arc emission spectroscopy. Representative spectra are displayed in Figures 2-4. 

V-Mo-Zeolite catalysts prepared by solid-state ion exchange were studied in the selective catalytic reduction of NOx by ammonia. The catalysts were characterized by chemical analysis, X-ray powder diffraction, N2 adsorption (BET), DRIFT, UV-Vis and Raman, spectroscopy and H2 TPR. Catalytic results show that upon addition of Mo to V-ZSM-5, catalytic performance was enhanced compared to V-ZSM-5. 

X-ray diffraction studies are usually carried out at room temperature under ambient conditions. It is possible, however, to perform variable-temperature XPD, wherein powder patterns are obtained while the sample is heated or cooled. Such studies are invaluable for identifying thermally induced or subambient phase transitions. Variable-temperature XPD was used to study the solid state properties of lactose [20], Fawcett et al. have developed an instrument that permits simultaneous XPD and differential scanning calorimetry on the same sample [21], The instrument was used to characterize a compound that was capable of existing in two polymorphic forms, whose melting points were 146°C (form II) and 150°C (form I). Form II was heated, and x-ray powder patterns were obtained at room temperature, at 145°C (form II had just started to melt), and at 148°C (Fig. 2 one characteristic peak each of form I and form II are identified). The x-ray pattern obtained at 148°C revealed melting of form II but partial recrystallization of form I. When the sample was cooled to 110°C and reheated to 146°C, only crystalline form I was observed. Through these experiments, the authors established that melting of form II was accompanied by recrystallization of form I. 

In 1976, an X-ray powder diffraction analysis of a substance obtained from Te02, dissolved in concentrated hydrofluoric acid, was performed (96). The orthorhombic crystals had the composition H2Te203F4. The structure was shown to be characterized by... 

Performance and Regulatory Requirements describes various ways of characterizing the dry powder aerosols and provides information on product quality performance requirements and how these attributes must be reflected in registration applications. 

The respirable powders of a DPI cannot be characterized adequately by single-particle studies alone bulk properties must also be assessed since they contribute to ease of manufacture and affect system performance. Primary bulk properties include particle size, particle size distribution, bulk density, and surface area. These properties, along with particle electrostatics, shape, surface morphology, etc., affect secondary bulk-powder characteristics such as powder fiow, handling, consolidation, and dispersibility. 

X-Ray powder diffraction is a powerful tool for characterization of zeolites. The basic experiment is relatively easy to perform and can be done in most labs on standard diffractometers and the data obtained is easy to analyze for many applications. Powder diffraction can be used to determine whether a new zeolite has been synthesized, whether a desired zeolite has been made or whether a crystallization process has completed. As noted in Section 4.2, X-ray powder diffraction can be an integral tool in determining the details of the structure of a newly synthesized zeolite. In addition, it is a critical characterization technique that can be routinely used, for example, to identify contaminants present in a synthesis, to determine how much zeolite has been bound into a catalyst or adsorbent pellet, or to ascertain if heat treatment alters the zeolite structure. Of the techniques described in this chapter, powder diffraction is probably the most commonly used. Additional details can be found elsewhere [15-19]. 

Table 3.4 summarizes the major properties of powders which need to be characterized in pre-formnlation. The effect of micronization (or other high energy processes), which is often applied to the powder (surface), should also be investigated as this may alter the properties of the powder during processing [64]. This may also alter the performance of the formulation. 

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