scholarly journals Influence of Mie scattering on nanoparticles with different particle sizes and shapes: Photometry and analytical ultracentrifugation with absorption optics

2005 ◽  
Vol 70 (3) ◽  
pp. 361-369 ◽  
Author(s):  
M.D. Lechner
Keyword(s):  
Analytical Ultracentrifugation ◽  
Mie Scattering ◽  
Precise Determination ◽  
Core Shell ◽  
Particle Sizes ◽  
Wide Range ◽  
Photometric Measurements ◽  
Shell Particles ◽  
Reliable Methods

Nanoparticles are used in large quantities for very different applications. A precise determination of the diameter and the particle size distribution which is responsible for the application properties is therefore essential. Reliable methods for measuring the above mentioned quantities are photometric measurements and analytical ultracentrifugation with an UV optics detector. Both methods are ruled by the Mie effect, that is scattering and absorption of the particles as function of the diameter, the wavelength, and the shape of the particles. The extinction coefficients ?=?/c for spheres, rods, and core shell particles have been calculated and plotted over a wide range of the size parameter ?d/?. Two examples for multimodal latex particles and core shell particles have been given and demonstrate the applicability of the method.

Characterization of Fluidization Quality in Fluidized Beds of Wet Particles

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Steven L McDougall ◽  
Mohammad Saberian ◽  
Cedric Briens ◽  
Franco Berruti ◽  
Edward W Chan
Keyword(s):  
Fluidized Bed ◽  
Fine Particles ◽  
Reactor Performance ◽  
Wide Range ◽  
Ball Velocity ◽  
Wet Particles ◽  
Fluid Coking ◽  
Reliable Methods

Monitoring the fluidization quality represents an operating challenge for many processes in which a liquid is sprayed into a gas-fluidized bed, such as fluid coking, fluid catalytic cracking, gas-phase polymerization, agglomeration and drying. Although the presence of liquid will generally have an adverse effect on fluidization, there are often strong incentives in operating with high liquid loadings. For the fluid coking process, for example, operating at lower reactor temperature increases yield and reduces emissions but increases the bed wetness, which may lead to local zones of poor mixing, local defluidization and a reduction in fluidization quality, compromising the reactor performance and stability. The objective of this study is to develop reliable methods to quantify the effects of liquids on fluidized beds.This study examined several methods to evaluate the fluidization quality. Each method was tested in a 3 m tall column, 0.3 m in diameter. Bed wetness was achieved with an atomized spray of various liquids, spanning a wide range of liquid properties.The introduction of liquid in a fluidized bed may result in the formation of wet agglomerates that settle at the bottom of the bed. The liquid may also spread on the particles, increasing their cohesivity and reducing the bed fluidity.Several experimental methods were developed to characterize the effect of liquids on fluidization. Some methods such as the falling ball velocity or the detection of micro-agglomeration from the entrainment of fine particles, are unaffected by agglomerates and detect only the change in bed fluidity. Other methods, such as deaeration or the determination of bubble size from the TDH, are affected by agglomerate formation and changes in bed fluidity.

Atomic Absorption Methods for the Direct Analysis of Metals and Alloys

1973 ◽  
Vol 27 (5) ◽  
pp. 335-341 ◽  
Author(s):  
Alan Walsh
Keyword(s):  
Atomic Absorption ◽  
Direct Analysis ◽  
Precise Determination ◽  
Metals And Alloys ◽  
Spectrochemical Analysis ◽  
Solid Samples ◽  
Trace Impurities ◽  
Wide Range

While atomic absorption methods of spectrochemical analysis have found a wide range of application, they have been almost entirely confined to the analysis of solutions. Solid samples for analysis have required prior solution. In recent months the situation has been transformed, and it has been demonstrated that some important metals and alloys can be analyzed directly by atomic absorption methods, which can be applied to the precise determination of major constituents and of trace impurities.

scholarly journals Bioanalytical Method Optimization for the Therapeutic Drug Monitoring of Vancomycin

2017 ◽  
Vol 2 (2) ◽  
pp. 89-95
Author(s):  
Maria Mercedes De Zan
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
High Performance ◽  
European Medicines Agency ◽  
Therapeutic Drug ◽  
Core Shell ◽  
Sample Treatment ◽  
Method Optimization ◽  
Shell Particles

Chemometric optimization and validation of a method based on High Performance Liquid Chromatography (HPLC) using core – shell particles for the determination of Vancomycin (VMC) in human plasma is reported. The combination of the efficiency of the core-shell particles and the benefits of the design of experiments allowed the successful determination of VCM, even in presence of several interferents. Selectivity, linearity, accuracy and precision were accomplished according to the European Medicines Agency (EMA) guideline, within the concentration range of 1.00 – 60.0 μg/mL of VCM. It is noteworthy that this method requires small amount of sample and solvents, and the sample treatment is simple and no time-consuming. Thus, this method becomes a simple and high-throughput alternative to therapeutic drug monitoring in treated patients, as well as an analytical procedure that conforms to the principles of the green chemistry.

Chosen applications and approaches to modeling lasers in dentistry

2021 ◽  
pp. 2150329
Author(s):  
Vladan Mirjanić ◽  
Milesa Srećković ◽  
Ðorđe Mirjanić ◽  
Aleksandar Bugarinović ◽  
Dragan Druzijanić ◽  
...  
Keyword(s):  
Short Pulse ◽  
Precise Determination ◽  
Living Tissue ◽  
Software Support ◽  
Dental Tissues ◽  
Wide Range ◽  
Laser Techniques ◽  
Therapeutic Doses ◽  
Tooth Tissue

Historically, although the first indications for the use of lasers in general were in dentistry, coming as a relief from the sound of the drill and mechanical contacts, it still seems somewhat that the entry in various ways of lasers in dentistry has been slower. This is somewhat true for the situation at the continents (e.g. USA much later approved the application relative to Europe). This paper analyzes the potential and existing applications of lasers in dentistry in a wide range of existing types, including interaction with dental tissues, in terms of surgical applications, on living tissue, the prosthetic area of applications and therapeutic doses. There is another special feature that can be recognized is the precise determination of the color of the material (teeth and prosthetics) and in general the determination of the composition of the material including classic, but also modern laser techniques (LIBS, complimentary techniques, tooth tissue, bone) and especially in the case of the first Q switch systems related to pain reduction, because the short pulse favors the intervention rate (ns, ps and fs). Special attention should be paid to modeling of interaction and analysis with the appropriate software support.

scholarly journals Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Raffaella Preti
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Food Analysis ◽  
High Performance ◽  
Separation Efficiency ◽  
New Technology ◽  
Core Shell ◽  
Shell Particles

The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis.

DISTANCE MEASUREMENTS USING FREQUENCY STABILIZED Nd:YAG LASERS

1996 ◽  
Vol 05 (03) ◽  
pp. 543-550
Author(s):  
VERED MAHAL ◽  
ADY ARIE
Keyword(s):  
Frequency Stability ◽  
Precise Determination ◽  
Phase Shifting ◽  
Distance Measurements ◽  
Fringe Contrast ◽  
Nd:Yag Lasers ◽  
Wide Range ◽  
Diode Pumped ◽  
Selection Of

Two diode-pumped tunable Nd:YAG lasers locked to sub-Doppler transitions of 127I2 and 133 Cs 2 are used as a source for two-wavelength interferometry. The synthetic wavelength, Λ=c/∆ν, is highly stable and accurate, owing to the frequency stability of the locked lasers and the precise determination of the frequency difference Δν between Cs 2 and I 2 transitions. The dense spectra of these molecules allows selection of Λ over a wide range, between 8.5 mm and several meters, thus enabling distance measurements with a large non-ambiguity range. Fringe contrast and phase-shifting methods are used to measure the phase difference. An accuracy of 70 μm is achieved for Λ~19 mm, i.e. Λ/260.

Real-Time Particle Size Measurements in Laser-Generated Plumes by Mie Scattering

1989 ◽  
Vol 43 (7) ◽  
pp. 1248-1251 ◽  
Author(s):  
Sandra M. Kimbrell ◽  
Edward S. Yeung
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Pyrolytic Carbon ◽  
Mie Scattering ◽  
Particle Sizes ◽  
Carbon Particles ◽  
Scattering Technique ◽  
Light Scattering Technique ◽  
Dissymmetry Ratio

We report the application of a light scattering technique for the determination of particle sizes in a laser-generated plume. This procedure is based on the dissymmetry ratio obtained for observation at different angles relative to the excitation source. Good spatial and temporal resolution is achieved. The plume can be probed repeatedly during its lifetime. Large carbon particles, on the order of 85 nm and larger, are observed in a plume generated from pyrolytic carbon.

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