Particle and Particle Systems Characterization (Part Part Syst Char)

Publications in this journal

• Article: Reciprocal response of human oral epithelial cells to internalized silica nanoparticles.

  Tay CY, Fang W, Setyawati MI, Sum CP, Chen X, Hong CHL, Leong DT
  Particle and Particle Systems Characterization 04/2013;
• Article: Visible-Light-Induced Directed Gold Microwires by Self-Organization of Nanoparticles on Aspergillus Niger

  Aneeqa Sabah, Prabhat Kumar, Waleed S Mohammed, Joydeep Dutta
  Particle and Particle Systems Characterization 01/2013;
• Article: Tunable Visible Emission of Luminescent Hybrid Nanoparticles Incorporating Two Complementary Luminophores: ZnO Nanocrystals and [Mo6Br14](2-) Nanosized Cluster Units

  T. Aubert, N. Nerambourg, N. Saito, H. Haneda, N. Ohashi, M. Mortier, S. Cordier, F. Grasset
  Particle and Particle Systems Characterization 01/2013; 30(1):90-95.
• Article: Multifunctional Polymer-Coated Carbon Nanotubes for Safe Drug Delivery

  Thomas L. Moore, Joshua E. Pitzer, Ramakrishna Podila, Xiaojia Wang, Robert L. Lewis, Stuart W. Grimes, James R. Wilson, Even Skjervold, Jared M. Brown, Apparao Rao, Frank Alexis
  Particle and Particle Systems Characterization 01/2013;
• Article: A Colloidal Silica Reference Material for Nanoparticle Sizing by Means of Dynamic Light Scattering and Centrifugal Liquid Sedimentation

  Olivier Couteau, Jean Charoud-Got, Hubert Rauscher, Fabio Franchini, François Rossi, Vikram Kestens, Katrin Franks, Gert Roebben
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  ABSTRACT: IRMM-304 is a new nanoparticle reference material (RM) consisting of silica nanoparticles suspended in an aqueous solution, of which the particle size was characterized by dynamic light scattering (DLS) and centrifugal liquid sedimentation (CLS). The homogeneity and stability of IRMM-304 were confirmed and three method-specific mean particle sizes around a nominal particle size of 40 nm were assigned to the material. The characterization tests have revealed a systematic deviation between the measurement results obtained with DLS and CLS. The availability of IRMM-304 makes it possible to study this difference between methods. Several possible causes for differences between the DLS and CLS results are suggested and preliminarily investigated, such as the interaction between particle and suspending medium, the particle shape and the effect of polydispersity on the size averaging procedure. These investigations are one illustration of the potential role of IRMM-304 and other nanoparticle RMs in the development, comparison, improved understanding, and quality assurance of nanoparticle sizing methods.
  Particle and Particle Systems Characterization 08/2011; 27(3‐4):112 - 124.
• Article: Oxidation of Nanometer‐Sized Titanium Nitride and Micrometer‐Sized Titanium Particles with Titanium Nitride Traces up to 1473 K in Air

  Olga Schulz, Norbert Eisenreich, Harald Fietzek, Maria del Mar Juez-Lorenzo, Evgenii Kondratenko
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  ABSTRACT: This study compares the oxidation behaviour of TiN particles (nanometer-sized to micrometer-sized) to titanium particles with traces of titanium nitride (micrometer-sized) regarding the similarities of the formation of the products. These particles were investigated between 323 K and 1473 K in air using high-temperature X-ray diffraction, SEM, and the methods of thermal analysis (TG and DSC). The oxidation of the nanometer-sized TiN particles forms anatase and rutile in two partially overlapping successive steps, whereas the anatase transforms completely to rutile at higher temperatures. The investigated titanium particles directly transform to rutile. Traces of TiN in titanium particles induce the formation of traces of anatase phase which similar to the oxidation of TiN particles transforms to rutile phase. A Jander model for three-dimensional diffusion was utilized for describing the oxidation kinetics of the both oxidation steps occurring with TiN. A least squares fit procedure gives good agreement of the calculated curves to measured TG and DSC curves and adequate approximation to intensities of X-ray measurements. The amount of TiN oxidized to anatase was found to be about 46 %. The kinetic parameters were determined: for the first step of TiN oxidation, the pre-exponential factor was 1.33 · 106 μm2/s and the activation energy was 180.5 kJ/mol as well as for the second step 5.51 · 103 μm2/s and 197.6 kJ/mol, respectively.
  Particle and Particle Systems Characterization 12/2010; 27(1‐2):48 - 58.
• Article: Mean Particle Diameters. Part VI: Fundamental Distinction between Statistics Based (ISO/DIN) and Physics Based (Moment‐Ratio) Definition Systems

  Maarten Alderliesten
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  ABSTRACT: Two methods to define mean particle diameters exist, viz., the statistics based ISO/DIN method and the physics based Moment-Ratio (M-R) method. The ISO/DIN method characterizes a size distribution by an average particle diameter of that distribution. The M-R method expresses mean diameters as ratios of two moments of a size distribution. The M-R method enables the user to derive mathematically or select empirically the type of mean diameter from the physical product or process property to be described by that mean diameter, irrespective the shape of the size distribution. The application of both definition methods to theoretical derivation and to empirical selection of that type of mean diameter is evaluated. The statistical character of the ISO/DIN system hampers its application to theoretical derivation and empirical selection of mean particle diameter types describing product or process properties. Although the ways of defining mean particle diameters according to both methods differ mathematically, a clear mathematical relationship exists.
  Particle and Particle Systems Characterization 12/2010; 27(1‐2):7 - 20.
• Article: Distortion of Single‐Particle Optical Sensing (SPOS) Particle Count by Sub‐Countable Particles

  Bruno Tolla, David Boldridge
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  ABSTRACT: Single particle optical sensing (SPOS) is a highly sensitive particle characterization technique for the measurement of the large particle (> 0.5 μm) tail of a submicron particle size distribution. We have examined the SPOS technique for fumed silica dispersions which have a mass mean particle size of ~140 nm. The reported large particle population varies as a highly non-linear function of sample concentration and is accompanied by the distortion of the particle size distribution. A similar response is also demonstrated for monodisperse polystyrene latex spheres. The source of spurious particle counts and the distortion of the particle size distribution is shown to be secondary coincidence. Model calculations indicate that the primary contributors to spurious counts are particles near the peak of the size distribution. These particles are substantially smaller than the nominal minimum 0.5 μm diameter. These findings establish the limited range of reliability for SPOS measurements when used to measure a small fraction of the total particle size distribution and establish the need for new particle characterization metrologies.
  Particle and Particle Systems Characterization 12/2010; 27(1‐2):21 - 31.
• Article: A Heuristic Model of Twin Fluid Internally Mixed Atomization using Distributed Weber Number Criterion

  Abhijit Kushari
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  ABSTRACT: This paper describes the development and predictions of a model that depicts the two-phase flow within an internally mixed air-assisted liquid atomizer using a statistical Weber number criterion. The main objective of this study is to develop an analytical tool that could be used in the design of internally mixed injectors and to predict the injector's flow and spray characteristics under different operating conditions. Basic conservation equations, along with appropriate boundary conditions, are used to model the two-phase air-liquid flow inside the injector. A statistically distributed Weber number criterion is used to estimate the sizes of the droplets being produced in the process. The liquid flow rates and mean droplet sizes, predicted by the model, are compared with the experimental data and they are found to be in fair agreement with each other.
  Particle and Particle Systems Characterization 12/2010; 27(1‐2):32 - 41.
• Article: Evaluation of Digital Image Discretization Error in Droplet Shape Measurement Using Simulation

  Sina Ghaemi, Payam Rahimi, David S. Nobes
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  ABSTRACT: Droplet shape measurement using image based techniques can be conducted using shape parameters which consist of a number of geometric features of a droplet image. The accuracy of calculating these shape parameters and their capability in revealing shape deviation is considerably affected by the discretization of the image with a camera CCD. In this paper, a simulation of digital images is conducted to investigate the error caused by image discretization. The effect of this error on calculating area, perimeter, and also a selected number of shape parameters are investigated. Digital images of circular and elliptical discs at different image/pixel size ratio and locations relative to the pixel grid have been generated to simulate the projected view. Results show that the shape parameters demonstrate different levels of sensitivity to the desirable factor of shape deviation and the undesirable factor of image discretization. A “clearance factor” has been suggested and used to rank the shape parameters based on their compensation between sensitivity to shape deviation and image discretization.
  Particle and Particle Systems Characterization 05/2010; 26(5‐6):243 - 255.
• Article: Determination of the Mechanical Properties of Powdered Agricultural Products and Sugar

  Alvaro Ramírez, Manuel Moya, Francisco Ayuga
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  ABSTRACT: Grain, forage cereals and different types of flour are commonly stored in silos. Their behavior within these structures is mainly governed by their mechanical properties. Since their advent, numerical methods have increasingly been used in silo design. However, the results obtained using these methods strongly depend on the variables employed to define the materials stored. Since the literature provides little information on the variables required for modeling the behavior of agricultural powdered materials, the goals of the present work were to: i) provide values for the different variables that are needed when designing silos using numerical methods (e.g., the Poisson ratio, the dilatancy angle and the modulus of elasticity, etc.), and ii) investigate the suitability of tests used in soil mechanics for powdered materials (e.g., the direct shear and the oedometric and triaxial test). Recommended values for these variables are proposed.
  Particle and Particle Systems Characterization 01/2010; 26(4):220 - 230.
• Article: Deconvolution with Maximum Entropy Solution to Determine Local Extinction Coefficient and Local Volume Concentration Values from Laser Diffraction Data

  Pisit Yongyingsakthavorn, Christophe Dumouchel, Pumyos Vallikul, Bundit Fungtammasan
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  ABSTRACT: The traditional use of the laser diffraction technique provides line-of-sight liquid spray drop-size distribution. However, deconvolution of the measurements can be performed for axisymmetric spray in order to determine local spray characteristics. In a previous publication, a new deconvolution technique making use of the maximum entropy principle was established and applied to determine the local drop-size distributions. The entire approach was experimentally validated. In this work, the technique is employed to determine local extinction coefficient values. As in the previous investigation, the measurement procedure consists of scanning a laser beam through the spray cross-section from the center to the edge of the spray. By use of the transmittance theory, the local extinction coefficients allow the local volume concentrations to be calculated. This theory introduces the mean scattering coefficient. The results show that this coefficient must be determined as a function of the Sauter mean diameter in order to avoid overestimation of the volume concentration. Although no proper validation is presented, the coherence of the overall approach is discussed in detail and solutions for improving the spatial resolution are presented. Finally, the local volume concentrations are combined with the local drop-size distribution to provide local volume-weighted, drop-size distributions. These distributions provide information on the localization of the drops according to their diameter as well as on the spatial liquid distribution. This work illustrates applications and performances of laser diffraction technique that are rarely used.
  Particle and Particle Systems Characterization 01/2010; 26(4):187 - 198.
• Article: Flow Dynamic Characterization of Cylindrical Particles

  Mohammad Asif
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  ABSTRACT: A detailed experimental characterization of the flow dynamics of a closely sized sample of cylindrical particles is reported here. Issues relevant to the design of reacting and nonreacting fluid-solid contacting devices, e.g., pressure drop behavior, fluidization behavior and settling behavior, both in Stokes law as well as the intermediate region, were investigated. The common approach of extending correlations meant for predicting the fluid dynamic parameters of spherical particles to nonspherical particles, with the help of the sphericity shape factor, such that particle diameter is the product of the equivalent volume diameter and the sphericity of the nonspherical particle, was examined here. Notwithstanding the simplicity of this approach, caution must be exercised as far as fluid dynamic parameters thus obtained are concerned. Significant error was observed here in all cases. However, improved predictions were obtained using available correlations whose parameters were optimized using a database of nonspherical particles.
  Particle and Particle Systems Characterization 12/2009; 26(4):210 - 219.
• Article: Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis

  Kumar Patchigolla, Derek Wilkinson
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  ABSTRACT: A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi-automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L-glutamic acid which crystallises into α (prismatic) or β (needle) form and the non-polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies.In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non-spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques.
  Particle and Particle Systems Characterization 12/2009; 26(4):171 - 178.
• Article: Real‐Time Measurement of the Size Distribution of Diesel Exhaust Particles using a Portable 4‐stage Electrical Low Pressure Impactor

  Dongho Park, Nak‐Kyoung Choi, Sang‐Gu Lee, Jungho Hwang
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  ABSTRACT: For this study, a 4 stage electrical low pressure impactor was designed to measure the real-time size distribution of diesel particulate matter (DPM). For the performance evaluation, sodium chloride (NaCl) particles and dioctyl sebacate (DOS) particles were used. After evaluating the collection efficiency of each stage of the impactor, the size distributions of test particles were estimated using electrical current data and their inversion algorithm, and this was found to agree with the results obtained by a scanning mobility particle sizer (SMPS). For measurement of DPM, a common-rail direct injection (CRDI) diesel engine, for engine speeds of 1,200 rpm and 1,500 rpm at 2.7 kgf·m, was used.Therefore, it was found that the size distribution of the DPM could be easily obtained, with the currents measured by the impactor and the data inversion algorithm, in less than 5 seconds. Furthermore, the effective density of the DPM could be obtained using the calculated results and the SMPS data.
  Particle and Particle Systems Characterization 11/2009; 26(4):179 - 186.
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  Available from: ku.edu

  Article: Transient Response of Particle Distribution in a Chamber to Transient Particle Injection

  Ning Zhang, Zhongquan Zheng, Steven Eckels, Venkata B. Nadella, Xiaoyang Sun
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  ABSTRACT: We inject a large number of newly created nano-particle aggregates into a chamber for the purpose of removing harmful contents in an indoor environment. This study is to experimentally and numerically investigate transient response of particle distributions to particle injections. A room-sized chamber of 4 m × 2.1 m × 2.4 m is connected to a specially designed particle-injection system, with two Optical Particle Counters used to simultaneously measure particle-number densities with the size range from 0.3 μm to 10 μm at the inlet and in the chamber. A velocity probe measures the flow that is up to 1 m/s. An Euler-type particulate-phase-transport model is developed and validated by comparing with experimental data. The study shows that the transient behavior of particle distributions is determined by many factors, including particle size, particle settling speed, sampling location, and velocity distribution. Particle number densities decrease in time more quickly for large particles than for small particles, and locations farther downstream in the chamber correlate more weakly with the inlet injection.
  Particle and Particle Systems Characterization 11/2009; 26(4):199 - 209.