Bimodal Particle Size Distribution Research Articles

Improving dirt pickup resistance in waterborne coatings using latex blends of acrylic/PDMS polymers

Abstract Improving dirt pickup resistance especially in waterborne coatings is critical to future coating innovations. This article focuses on resins used in the coatings with the aim of enhancing dirt pick up resistance. It presents initially optimization of an acrylic (BA-St-AA) copolymer synthesized through free-radical emulsion polymerization and also, a polydimethylsiloxane (PDMS) homopolymer via cationic ring opening macro-emulsion polymerization of octamethyl cyclotetrasiloxane (D4). Concentration of monomers, Type of anionic emulsifiers, impeller stirrer speed and reaction temperature were considered as variables in order to reach a high yield of conversion and colloidal stability. The polymers were characterized using fourier transfer infrared spectroscopy, gel permeation chromatography and particle size analysis. The optimized latexes were then blended in different ratios (0/100–100/0) and the properties of the films were assessed using optical microscopy, Si-mapping EDX analysis, contact angle measurement, water up-take, and color measuremets as well as stress strain analysis. The characterization results revealed latexes with optimized conversion and uni-modal particle size distribution (PSD) were synthesized (PDMS: PSD 25–250 nm, M n 129000, PDI 2.23 and Acrylic: PSD 75–400 nm, M n 61,000, and PDI 4.95). It was found that 10–28 wt% PDMS in blends provides continuous and clear films with low dirt pickup properties. The optimized latex blend film showed a drying time of 25 min, contact angle of 96°, water uptake of 27% after 6 days, tensile strength of 7 MPa, and elongation at break of 690%. The results confirmed that blending acrylic and silicone latexes in bi-modal PSD and optimized ratios leads to a good performance exterior and uniform hydrophobic coating.

Effect of Gd doping on the structural, optical band-gap, dielectric and magnetic properties of ZnO nanoparticles

Nanostructured Zn1−xGdxOδ (0≤x⩽0.02) powders were synthesized by the combustion reaction method (CR) with the purpose to investigate the effect of Gd doping on the structural, optical band-gap, dielectric and magnetic properties at room temperature. The structure and morphology of all samples were characterized by X-ray diffraction (XRD), and transmission electron microscope (TEM). The XRD patterns of all samples exhibited sharp and intensive peaks of hexagonal wurtzite structure of ZnO without any evidence of spurious crystalline phases. The nanoparticles crystalized in roughly spherical morphology with bimodal particle size distribution centered at ∼30, ∼100 and ∼70, ∼160nm for undoped and Gd – doped ZnO (x=0.02), respectively. Diffuse reflectance spectrum of each sample was obtained by using a UV/VIS/Near spectrometer and the optical band-gap, Eg, values decreased with increasing Gd doping concentration; being ∼3.23, and ∼3.17eV for x=0 and 0.02, respectively at room temperature. This red shift on the band-gap was discussed in terms of new band levels below the conducting band. Also, the dielectric permittivity data of all samples could be evaluated by the Cole– Cole model. Seems that both oxygen vacancies (VO) or/and interstitial oxygen (O″ı¨) defects present in the Gd – doped ZnO samples play an important rule in the dielectric permittivity at room temperature. Furthermore, all Gd – doped ZnO samples exhibited typical paramagnetic behavior at rom temperature.

Response of suspended sediment particle size distributions to changes in water chemistry at an Andean mountain stream confluence receiving arsenic rich acid drainage

AbstractAcid drainage is an important water quality issue in Andean watersheds, affecting the sustainability of urban, agricultural, and industrial activities. Mixing zones receiving acid drainage are critical sites where changes in pH and chemical environment promote the formation and dissolution of iron and aluminum oxy/hydroxides. These particles can significantly change the speciation of toxic metals and metalloids throughout drainage networks via sorption, desorption, and settling processes. However, little is known about the behavior of particle size distributions (PSDs) in streams affected by acid drainage and their relationship to metal speciation. This work studied: (a) the PSDs for a wide range of mixing ratios found at a fluvial confluence affected by acid drainage, and (b) the response of PSDs and arsenic speciation to environmental changes found when the particles approach complete mixing conditions. The confluence between the Azufre River (pH ~ 2, high concentration of dissolved metals) and Caracarani River (pH = 8.6, low concentration of dissolved metals) was used as a representative model for study. Field measurements show a bimodal PSD with modal diameters of ~50 and 300 μm. At shorter distances from the junction, the smaller modes with smaller particle volumes were dominant across the stream cross‐sections. A systematic shift towards larger particle sizes and larger particle volumes occurred downstream. The analysis of laboratory PSDs for Azufre/Caracarani mixing ratios between 0.01 and 0.5 (pH from 6.2 to 2.3) showed a bimodal trend with ~15 and 50 μm characteristic diameters; larger particles formed at pH>4. When particle suspensions were transferred in laboratory experiments from very low pH to full mixing conditions (pH ~ 2.8 and mixing ratio ~ 0.25) particle sizes varied, and the dissolved arsenic concentration decreased. The observed reaction kinetics were slow compared to the time scale of advective transport, creating opportunities for engineered controls for arsenic. This work contributes to a better understanding of the chemical‐hydrodynamic interactions in watersheds affected by mining, and identifying opportunities to improve water quality at points of use.

Microphysical particle properties derived from inversion algorithms developed in the framework of EARLINET

Abstract. We present a summary on the current status of two inversion algorithms that are used in EARLINET (European Aerosol Research Lidar Network) for the inversion of data collected with EARLINET multiwavelength Raman lidars. These instruments measure backscatter coefficients at 355, 532, and 1064 nm, and extinction coefficients at 355 and 532 nm. Development of these two algorithms started in 2000 when EARLINET was founded. The algorithms are based on a manually controlled inversion of optical data which allows for detailed sensitivity studies. The algorithms allow us to derive particle effective radius as well as volume and surface area concentration with comparably high confidence. The retrieval of the real and imaginary parts of the complex refractive index still is a challenge in view of the accuracy required for these parameters in climate change studies in which light absorption needs to be known with high accuracy. It is an extreme challenge to retrieve the real part with an accuracy better than 0.05 and the imaginary part with accuracy better than 0.005–0.1 or ±50 %. Single-scattering albedo can be computed from the retrieved microphysical parameters and allows us to categorize aerosols into high- and low-absorbing aerosols. On the basis of a few exemplary simulations with synthetic optical data we discuss the current status of these manually operated algorithms, the potentially achievable accuracy of data products, and the goals for future work. One algorithm was used with the purpose of testing how well microphysical parameters can be derived if the real part of the complex refractive index is known to at least 0.05 or 0.1. The other algorithm was used to find out how well microphysical parameters can be derived if this constraint for the real part is not applied. The optical data used in our study cover a range of Ångström exponents and extinction-to-backscatter (lidar) ratios that are found from lidar measurements of various aerosol types. We also tested aerosol scenarios that are considered highly unlikely, e.g. the lidar ratios fall outside the commonly accepted range of values measured with Raman lidar, even though the underlying microphysical particle properties are not uncommon. The goal of this part of the study is to test the robustness of the algorithms towards their ability to identify aerosol types that have not been measured so far, but cannot be ruled out based on our current knowledge of aerosol physics. We computed the optical data from monomodal logarithmic particle size distributions, i.e. we explicitly excluded the more complicated case of bimodal particle size distributions which is a topic of ongoing research work. Another constraint is that we only considered particles of spherical shape in our simulations. We considered particle radii as large as 7–10 µm in our simulations where the Potsdam algorithm is limited to the lower value. We considered optical-data errors of 15 % in the simulation studies. We target 50 % uncertainty as a reasonable threshold for our data products, though we attempt to obtain data products with less uncertainty in future work.

Rheological behaviour and stability characteristics of biochar-water slurry fuels: Effect of biochar particle size and size distribution

The effect of particle size and size distribution on the rheological properties and stability characteristics of biochar-water slurry fuels was investigated. The biochar-water slurry fuels were prepared by dispersing biochar samples in water as the suspending medium. Slurries with varied median particle size (D50) of biochar, unimodal size distribution of biochar with varied D50, and bimodal size distribution with varied size ratio of coarse to fine fractions (λ) and varied fine particle fraction content (ξ) were prepared. The yield stress of the slurries prepared was measured using a Brookfield vane viscometer while the dependence of the apparent viscosity and shear stress on the shear rate was characterised using a Haake VT550 cone and plate viscometer. The stability of the slurry fuels was characterised using a “drop rod” method. At a given biochar loading, the yield stress of the slurry fuel first decreased slightly with increasing D50 for D50<~15μm and then increased dramatically with further increasing D50 due to the stronger water uptake capacity of larger biochar. The biochar of bimodal size distribution reduced the viscosity and thus increased maximum biochar loading. The viscosity was further reduced as λ decreased, being more profound at smaller ξ. The slurry fuels prepared with finer biochar were more stable. The stability of slurry fuels of bimodal particle size distribution was greater at higher ξ for a given λ.

Combining gas-phase electrophoretic mobility molecular analysis (GEMMA), light scattering, field flow fractionation and cryo electron microscopy in a multidimensional approach to characterize liposomal carrier vesicles

For drug delivery, characterization of liposomes regarding size, particle number concentrations, occurrence of low-sized liposome artefacts and drug encapsulation are of importance to understand their pharmacodynamic properties. In our study, we aimed to demonstrate the applicability of nano Electrospray Gas-Phase Electrophoretic Mobility Molecular Analyser (nES GEMMA) as a suitable technique for analyzing these parameters. We measured number-based particle concentrations, identified differences in size between nominally identical liposomal samples, and detected the presence of low-diameter material which yielded bimodal particle size distributions. Subsequently, we compared these findings to dynamic light scattering (DLS) data and results from light scattering experiments coupled to Asymmetric Flow-Field Flow Fractionation (AF4), the latter improving the detectability of smaller particles in polydisperse samples due to a size separation step prior detection. However, the bimodal size distribution could not be detected due to method inherent limitations. In contrast, cryo transmission electron microscopy corroborated nES GEMMA results. Hence, gas-phase electrophoresis proved to be a versatile tool for liposome characterization as it could analyze both vesicle size and size distribution. Finally, a correlation of nES GEMMA results with cell viability experiments was carried out to demonstrate the importance of liposome batch-to-batch control as low-sized sample components possibly impact cell viability.

Technical description of the microinjection pump (MIP®) and granulometric characterization of the aerosol applied for pressurized intraperitoneal aerosol chemotherapy (PIPAC).

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is gaining acceptance in clinical practice, but detailed information about the microinjection pump (MIP®), the generated aerosol and drug distribution is missing. Ex vivo granulometric analyses by means of laser diffraction spectrometry were performed for MIP® aerosol characterization. Beside the standard operation conditions, the impact of the volumetric liquid flow rate on the aerosol characteristics was investigated with different liquids. Granulometric results as well as the local drug distribution were verified by ex vivo gravimetric analyses. On the basis of determined MIP® characteristics, the aerosol droplet size, which is necessary for a homogenous intra-abdominal drug distribution, was calculated. Granulometric analyses showed that the MIP® aerosol consists of a bimodal volume-weighted particle size distribution (PSD3) with a median droplet diameter of x 50,3=25µm. Calculations reveal that the droplet size for a homogenous intra-abdominal drug distribution during PIPAC therapy should be below 1.2µm. We show that >97.5vol% of the aerosolized liquid is delivered as droplets with ≥3µm in diameter, which are primarily deposited on the surface beneath the MIP® by gravitational settling and inertial impaction. These findings were confirmed by ex vivo gravimetric analyses, where more than 86.0vol% of the aerosolized liquid was deposited within a circular area with a diameter of 15cm. The granulometric aerosol properties, as well as the aerodynamic conditions achieved by standard MIP® operation, do not support the idea of widespread or homogenous drug distribution in the abdominal cavity.

Investigation of optical, structural, morphological and antimicrobial properties of carboxymethyl cellulose capped Ag-ZnO nanocomposites prepared by chemical and mechanical methods

This study reports on preparation and investigation of novel Ag-ZnO nanocomposites with antimicrobial activity. Carboxymethyl cellulose (CMC) capped Ag-ZnO nanoparticles (NPs) were synthesized by chemical (CD) and mechanical deposition (MD) of Ag NPs on ZnO NPs. The samples were investigated by UV–Vis spectroscopy, FTIR, XRD, DLS, SEM, EDX, WDXRF and TEM analyses. The antimicrobial activity was assessed against a wide range of pathogenic microorganisms in planktonic and adherent state. Ag-ZnO nanocomposites exhibited maximum 0.64wt.% spherical Ag NPs deposited on hexagonal prism ZnO NPs with single surface plasmon absorption band ranging 398–424nm. The mechanism for obtaining CMC capped Ag-ZnO NPs by chemical synthesis was proposed. Ag-ZnO nanocomposites yielded average crystallite size of 56.1–64nm, mean effective diameter of 388–427nm, polydispersity of 0.193–0.286, and a bimodal volume-weighted particle size distribution. All nanomaterials exhibited good antimicrobial activity against planktonic and biofilm growing bacteria.

Compressive Behavior of Idealized Granules for the Simulation of Composition C‐4

AbstractIn the most common approach to detect trace explosives at security checkpoints, any illicit residues must first be removed from the surface of interest (contact sampling) before they are delivered to a detector, such as an ion mobility spectrometer. Contact sampling involves applying a compressive shearing load to dislodge the residue from a surface. Optimizing this step requires an understanding of the properties of the residues and their effect on residue behavior. This study seeks to evaluate the previously unstudied effect of the binder mechanical properties and particle size distributions on the behavior of Composition C‐4. Composition C‐4 demonstrates complex granular behavior, and contains a highly viscous, non‐Newtonian binder. In addition to studies of real C‐4, simulated C‐4 was created with mechanical properties very similar to the real composite. The results with the live and simulated C‐4 indicate that – while highly important – the binder is not the only driving parameter controlling granule deformation under load; to create an effective simulant the binder must be combined with particles of an appropriate bimodal particle size distribution.

The influence of mechanical activation on the morphological changes of Fe/BaTiO3 powder

Crystal structure and morphology of mechanically activated nanocrystalline Fe/BaTiO3 was investigated using a combination of spectroscopic and microscopic methods. These show that mechanical activation led to the creation of new surfaces and the comminution of the initial powder particles. Prolonged milling resulted in formation of larger agglomerates of BaTiO3 and bimodal particle size distribution, where BaTiO3 particles were significantly larger than those of iron-containing phases. Milling times of 210min and above lead to a significant decrease in temperature of the oxidation of iron in the sample, indicating abrupt change in reactivity. Raman spectroscopy analysis has revealed that activation had a pronounced influence on Fe/BaTiO3 lattice, thereby affecting both the stability of the crystal structure and the phase transition phenomena.

Effect of the particle size and the debinding process on the density of alumina ceramics fabricated by 3D printing based on stereolithography

In this study, Al2O3 ceramics were printed by stereolithography from particles with different particle size distributions, which are the micro-sized Al2O3, nano-sized Al2O3, and a mixture of both. The influence of the particle size and the debinding method on the density and morphology of the sintered bodies were investigated. The density of the samples containing both micro-sized and nano-sized alumina particles is highest among the three samples. Furthermore, the samples subjected to the vacuum debinding showed a higher density compared with the samples subjected to the traditional thermal debinding. The results suggest that the combination of a powder with a bimodal particle size distribution and the vacuum debinding process offers an effective way to print 3D ceramics with a good performance through stereolithography.

Indoor Nanoparticles Measurements in Workplace Environment: The Case of Printing and Photocopy Center.

In recent studies, laser printers and photocopy machines have been identified as important sources of indoor air pollution with fine and ultrafine particles. In this work, the indoor pollution of a printing and photocopy center in Ljubljana, Slovenia was investigated. The particle number concentration time series and the particle size distributions were measured continuously for a period of one month by a scanning mobility particle sizer (SMPS). Our measurements clearly showed that during operating hours the total number concentration of nanoparticles (size between 15 and 750 nm) increased in both working rooms with laser printers as well as in a room with photocopy machines. In rooms with laser printers the bimodal particle size distribution was frequently observed (i.e. max. at ca. 20 or 30 nm and at ca. 100 nm), with the aged particles persisted in the room over the night and over the weekend. In the photocopy room the situation was different, again with a sharp increase in concentration of small particles (ca 20 nm) and their growth to bigger sizes, but after closing a decrease to the background concentration. The results undoubtedly proved that the fast increase in nanoparticles (size below 50 nm) was associated with processes, the intense laser printing and photocopying activity. Our study also confirmed that the ventilation of the room is a very important factor which affects the life time of aged nanoparticle in the indoor environment.

Encapsulation of Vitamin B2 in solid lipid nanoparticles using supercritical CO2

Solid lipid nanoparticles (SLN) are spherical particles prepared from solid fats, which can be used as delivery systems by encapsulating bioactives. In this study, particles from gas-saturated solutions (PGSS) were produced by a modified process, using fully hydrogenated canola oil (FHCO) to encapsulate Vitamin B2, a hydrophilic bioactive. Four operating parameters were studied in terms of their influence on encapsulation efficiency, bioactive load and particle size: pressure (10.0–25.0MPa), Vitamin B2 concentration (0.25–2%, w/w), surfactant (sodium lauryl sulfate, SLS) concentration (1–7.5%, w/w) and stabilizer (polyethylene glycol, PEG) molecular weight (2,000–35,000Da). The optimal conditions were determined as 15.0MPa, 2% Vitamin B2, 5% SLS and 35,000Da PEG, resulting in an encapsulation efficiency of 12±0.03%, bioactive load of 0.54±0.05mg/g and bimodal particle size distribution with a main peak at 104±5.7nm, showing that it is possible to generate nano-scale solid lipid particles with a high content of a hydrophilic bioactive; however, further fine tuning is needed.

Influence of WC carbide particle size on the microstructure and abrasive wear behavior of WC–10Co–4Cr coatings for aircraft landing gear

WC–Co–Cr thermal spray coatings are possible replacements for hard chrome plating on aircraft landing gear because of their superior wear resistance and environmentally friendly properties. In this study, four HVOF spray WC–10Co–4Cr coatings were deposited. During deposition, WC (tungsten carbide) particles were mixed into the coating. These included two types of single particle size distributions and two types of bimodal particle size distributions. The microstructure and abrasive wear behavior of these coatings were studied. The relationship among WC particle distributions, the deposit microstructure, and the three-body abrasive wear rates by rounded quartz grains was determined. The coating that only contained single particle size distribution of 1.2μm-sized WC particles exhibited the best abrasive wear resistance.

Characterization and biological activities of cyclic (1→3, 1→6)-β-glucans from Bradyrhizobium japonicum.

To isolate cyclic(1→3, 1→6)-β-glucan from Bradyrhizobium japonicum MTCC120, to characterize its structure and to study its biological activities. The degree of polymerization of cyclic (1→3, 1→6)-β-glucan varied between 10 and 13 and with substituents acetyl, succinyl and phosphocholine. The cyclic glucans showed bimodal particle size distribution, with hydrodynamic diameters of 1.92 and 231nmcorresponding to monomeric and aggregated cyclic glucans, respectively. SEM and TEM images showed that the glucans formed aggregates of nanorods. The glucans were biocompatible, exhibited good antioxidant activity and had the abilities to bind to Aniline Blue dye to form a fluorescence complex which was concentration dependent. The glucans isolated are cyclic and have good antioxidant activities, hence have potential application in food and pharmaceutical industries. Their dye binding ability could be exploited in medical imaging to reduce the cytotoxicity of the dyes.

Structural, Thermal and Magnetic Properties of Nanocrystalline Co80Ni20 Alloy Prepared by Mechanical Alloying

Co80Ni20 powder mixture was mechanically alloyed by high-energy planetary ball milling, starting from elemental Co and Ni metal powders. The morphological, microstructural, thermal and magnetic properties of the milled powders were characterised respectively by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and vibratory sample magnetometry. In addition to a highly disordered phase, two face-centred cubic (FCC) and hexagonal close-packed (HCP), solid solutions, FCC Co(Ni), FCC Ni(Co) and HCP Co(Ni), are observed after 3 h of milling. Their grain sizes decrease with increase in milling time attaining, at 48 h of milling, 12 nm, 25 nm and 10 nm, respectively. Beyond a certain milling time, no further refinement of the microstructure occurs and the morphological equilibrium is usually given by a bimodal particle size distribution. Magnetic measurements of the milled Co80Ni20 alloy powder exhibit a soft ferromagnetic character where the magnetic parameters are sensitive to the milling time mainly due to the particle size refinement as well as the formation of Co(Ni) and Ni(Co) solid solutions. Both the saturation magnetisation ( Ms) and coercivity ( Hc) were found to decrease with milling time, attaining the values of Ms = 126 emu/g and Hc = 60 Oe after 48 h of milling.

Real-Time Measurement of Electronic Cigarette Aerosol Size Distribution and Metals Content Analysis.

Electronic cigarette (e-cigarette) use is increasing worldwide and is highest among both daily and nondaily smokers. E-cigarettes are perceived as a healthier alternative to combustible tobacco products, but their health risk factors have not yet been established, and one of them is lack of data on aerosol size generated by e-cigarettes. We applied a real-time, high-resolution aerosol differential mobility spectrometer to monitor the evolution of aerosol size and concentration during puff development. Particles generated by e-cigarettes were immediately delivered for analysis with minimal dilution and therefore with minimal sample distortion, which is critically important given the highly dynamic aerosol/vapor mixture inherent to e-cigarette emissions. E-cigarette aerosols normally exhibit a bimodal particle size distribution: nanoparticles (11-25nm count median diameter) and submicron particles (96-175nm count median diameter). Each mode has comparable number concentrations (10(7)-10(8) particles/cm(3)). "Dry puff" tests conducted with no e-cigarette liquid (e-liquid) present in the e-cigarette tank demonstrated that under these conditions only nanoparticles were generated. Analysis of the bulk aerosol collected on the filter showed that e-cigarette emissions contained a variety of metals. E-cigarette aerosol size distribution is different from that of combustible tobacco smoke. E-cigarettes generate high concentrations of nanoparticles and their chemical content requires further investigation. Despite the small mass of nanoparticles, their toxicological impact could be significant. Toxic chemicals that are attached to the small nanoparticles may have greater adverse health effects than when attached to larger submicron particles. The e-cigarette aerosol size distribution is different from that of combustible tobacco smoke and typically exhibits a bimodal behavior with comparable number concentrations of nanoparticles and submicron particles. While vaping the e-cigarette, along with submicron particles the user is also inhaling nano-aerosol that consists of nanoparticles with attached chemicals that has not been fully investigated. The presence of high concentrations of nanoparticles requires nanotoxicological consideration in order to assess the potential health impact of e-cigarettes. The toxicological impact of inhaled nanoparticles could be significant, though not necessarily similar to the biomarkers typical of combustible tobacco smoke.

Crystallization Behavior of Amorphous Si3N4 and Particle Size Control of the Crystallized α-Si3N4.

Amorphous silicon nitride powder prepared by low-temperature vapor-phase reaction was heat treated at various temperatures for different periods of time to examine the crystallization behavior. The effects of the heat-treatment temperature and duration on the degree of crystallization were investigated along with the effect of the heat-up rate on the particle size, and its distribution, of the crystallized α-phase silicon nitride powder. A phase transition from amorphous to α-phase occurred at a temperature above 1400 degrees C. The crystallization. process was completed after heat treatment at 1500 degrees C for 3 h or at 1550 degrees C for 1 h. The crystallization process starts at the surface of the amorphous particle: while the outer regions of the particle become crystalline, the inner part remains amorphous. The re-arrangement of the Si and N atoms on the surface of the amorphous particle leads to the formation of hexagonal crystals that are separated from the host amorphous particle. The particle size and size distribution can be controlled by varying the heat-treatment profile (namely, the heat-treatment temperature, heating rate, and heating duration at the specified temperature), which can be used to control the relative extent of the nucleation and growth. The completion of most of the nucleation process by lowering the heat-up rate can be used to achieve a singlet particle size distribution. Bimodal particle size distribution can be achieved by fast heat-up during the crystallization process.

Performance evaluation of a dense-medium cyclone using alternative silica-based media

The production of superior metallurgical-grade silicon requires the use of ultra-clean coal containing <1.5% ash with no iron contamination. The magnetite suspension utilized for coal cleaning in a dense-medium cyclone (DMC) is a detrimental impurity in the final coal product that dramatically diminishes the purity of silicon. A prior study has demonstrated that several silica-based materials may be suitable alternatives that eliminate iron contamination. To further improve the separation performance and evaluate the silica-based media, DMC separation tests were conducted based on a statistically designed program to identify the role of various operational parameters (i.e. medium relative density, silica media blend ratio, and cyclone apex diameter) in maximizing organic efficiency and minimizing low-density bypass. An ideal medium composition with a bimodal particle size distribution considerably improves medium stability properties while also eliminating the undesirable effects of apex diameter on the DMC separation efficiency. Low-density cutpoints (<1.35) are hindered by medium instability, but these issues can be rectified by increasing the amount of fine media particles or decreasing the apex diameter.

Effect of sieve particle size on functional, thermal, rheological and pasting properties of Indian and Turkish lentil flour

The influence of particle size (74–210 μm) on compositional, functional, rheological, thermal and pasting properties of two commercial lentil flour samples (Indian and Turkish) was investigated. Reduction of particle size significantly affected the composition of the flour. Turkish lentil flour fractions had higher bulk density (480–600 kg/m3) than Indian one. Particle size did not influence the water holding capacity of flour, however, the process temperature increased those parameters significantly. Instrumental color parameters a and b reduced abruptly and the lightness value, L increased while the particle size was reduced from 210 to 74 μm. Laser diffraction analysis showed bimodal particle size distributions of lentil flour. Two distinct thermal transitions exhibited by lentil samples and the glass transition temperature varied among samples. Non-isothermal heating of lentil particle dispersions demonstrated a gradual decrease in the peak complex viscosity with decreasing particle size. Pasting parameters and micrographs of lentil fractions showed a significant difference between two samples. The obtained results could be useful for the food industry to manufacture lentil-based food products with a defined particle size to obtain desirable functional and rheological characteristics.