Particle Crystalline Structure Research Articles

Fabrication, physicochemical properties and structural characteristics of nanoparticles from carrot pomace and its insoluble dietary fiber

Modifying insoluble dietary fiber (IDF) to improve its application has received a growing interest in the food industry. In this study, carrot pomace and extracted IDF nanoparticles (CPNPs and IDFNPs, respectively) were produced in the sequence of milling, homogenization, and ultrasonication which resulted in the breakdown of particles and subsequently, the formation of NPs with sizes of ∼200 nm. The results demonstrated that nanosizing treatment effectively pulverized the particle sizes of CP (279 μm–203 nm). As the particle size decreased, ζ-potential (−17.9 to −22.9 mV), WHC (17.1–19.7%), and OHC (3.7–19.3%) tended to increase significantly (p < 0.05), in which, the highest WHC (21.29 g/g), OHC (25.49 g/g), as well as the absolute value of the ζ-potential (−38.8 mV) and the smallest contact angle (23.795°) were detected for IDFNPs. SEM images also revealed an increment in surface porosity after nanosizing process. However, based on XRD analysis, the crystalline structure of particles was not obviously different, which was confirmed by the results of FTIR spectroscopy. The results revealed carrot pomace NPs could be suitable for typical nanoparticle applications, such as Pickering stabilizers, emulsifiers, thickeners, and even fat replacers.

Biosynthesis of zinc oxide nanoparticles using bacteria: a study on the characterization and application for electrochemical determination of bisphenol A

Biosynthesis of zinc oxide nanoparticles was carried out by two bacterial strains namely Lactococcus lactis NCDO1281(T) and Bacillus sp PTCC 1538. The produced particles were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Dispersive X-ray Spectroscopy (EDX) analyses. Pure hexagonal crystalline structure of particles was confirmed by XRD spectra and FTIR analysis confirmed the synthesis of zinc oxide. The SEM analysis revealed that zinc oxide produced by B. sp was nano-rods with an average diameter of 99 nm, whereas L. lactis produced nano-spheres with diameter sizes in the range of 55–60.5 nm. Electrochemical sensors based on the biosynthesized nanoparticles and modified carbon paste electrodes were developed for determination of bisphenol A, among which zinc oxide from B.sp exhibited the better performance than the other one. Bisphenol A (BPA) oxidation peak current was about 144.849 µA at the surface of the electrode which was modified with these nanoparticles that is about 5 times more than that of bare electrode. In order to evaluate the stability of nanoparticles, the powders were tested again after six months, and this time the ZnO nanoparticles produced by L. lactis had a better performance than the zinc oxide from B.sp. BPA oxidation peak current was about 75.82 µA at the surface of the electrode that is about 2.7 times more than that of bare electrode.

Solid lipid microparticles produced by spray chilling technique to deliver ginger oleoresin: Structure and compound retention

Ginger oleoresin (GO) is frequently used as a flavor ingredient in various foods. Besides flavoring, its bioactive compounds are known for antimicrobial and antioxidant properties. In this study, we investigated the formation and characterization of solid lipid microparticles (SLMs) loaded with GO by the spray chilling technique. Mixtures composed of palmitic acid with oleic acid or palm fat were used as carriers. DSC and X-ray diffraction showed that the particle crystalline structure was decreased by oleic acid. Retention of pungent and volatile compounds was higher than 96% and 75%, respectively, in the best formulations. FTIR spectroscopy revealed no chemical interaction between GO and carriers. The particles presented a spherical shape and rough surface, and GO was dispersed over the entire particles, as shown by confocal microscopy. High volatile and pungent compound retention have shown that spray chilling can be a very promising technique for the production of SLM loaded with GO.

Heat Transfer in Semitransparent Gas-Permeable Materials with the Spectral Dependence of Optical Properties

Introduction. Radiative heat transfer in porous insulating materials at high temperatures was investigated in [1–3], and compound heat transfer under unsteady-state conditions in a material was investigated in [4]. Radiation transfer in the gray medium approximation substantially limits the adequacy of the model used in [5]. The present work, which is a continuation of [5], was performed by us with a view to account for the dependence of the optical properties of gas-permeable materials on radiation wavelength. The article describes a computational investigation of compound heat and mass transfer in a semitransparent gas-permeable material in the presence of phase transition and oxygen chemisorption in pores. An innovation in the formulation of the problem is accounting for the interaction of the radiation fi elds of optical inhomogeneities (pores and the particles intruded into a material) when calculating the material�c s optical properties. The optical properties of particles are usually calculated by the Mie theory [6], but at high concentrations the radiation fi elds of individual particles overlap, which is not taken into account in the Mie theory and leads to a large error in the calculated properties. To avoid the occurrence of such an error, in the present work the optical properties at a high particle concentration are calculated by means of the Maxwell–Garnett approximation [7] that accounts for the interaction of the radiation fi elds of the indicated inhomogeneities. Physical Model. We studied quartz that contained pores fi lled with air and vanadium dioxide particles in which 2 nd -order dielectric–metal phase transformations occur with heat liberation during cooling and heat absorption upon heating. Heat exchange with the surrounding medium proceeds by radiation and convection. We consider the processes of heat and mass transfer in a thin gas-permeable plane layer in one-dimensional approximation under conditions where radiative heat transfer is comparable with heat conduction in the solid skeleton and gas convection in the pores. Under conditions of heating or cooling, 2 nd -order dielectric–metal phase transition occurs in the vanadium dioxide particles, which is accompanied by oxygen chemisorptions and by a change in the crystalline structure of particles, with simultaneous liberation or absorption of heat in the material. These processes can be modeled by volumetric heat and mass sources that are introduced into the effective heat capacity of the material [5]. The absence of large pressure gradients in the gas leads to a relatively slow gas fi ltration, which allows us to assume that thermal equilibrium was achieved between the solid skeleton and the gas. The problem formulated is solved in the following approximation: the material under study is considered as a set of three continua inserted into one another. The components of this set are the continua of air in the pores, quartz (the material skeleton), and of the vanadium dioxide particles introduced into the skeleton. The thermophysical properties of continuous components are the effective properties in relation to the corresponding properties of a real material. Gas fi ltration in a material is modeled as the motion of a continuous air component characterized by a velocity fi eld and by the fi eld of specifi c air fl ow rates. Radiative transfer in the system considered occurs through the solid skeleton and gas in the pores. In modeling the radiative transfer, we took into account the processes of the radiation absorption, emission, and scattering. We assumed that the optical properties of a material were dependent on the wavelength. The effective heat capacity of the material depends on temperature and

Study on Preparation and the Characteristics of Environment-Friendly Ce-Ti-Mn Conversion Coating on Aluminum Alloy 6061

Preparation and the characteristics of environment-friendly Ce-Ti-Mn conversion coating on aluminum alloy 6061 were investigated by XRD, FESEM, EDS, TEM and AFM in this paper. It is indicated that coating characteristics such as the surface morphologies, microstructure and corrosion resistance, are greatly influenced by the formation technology at room temperature. The constituents and their concentration, and pH value of the conversion solution have an important role on the feature of Ce-Ti-Mn conversion film, which will significantly influence on the continuity, compactness and the crystalline structure of particles of the film. The concentrations of the main salt K2TiF6and oxidizer KMnO4have significant effect on the characteristics of the conversion coating. The Ce-Ti-Mn film grows in a lamellar way, composing of oxide and/ or hydroxide phases of Ce, Ti and Mn, some of which are amorphous. The formation mechanism of the Ce-Ti-Mn conversion coating is discussed in detail.

Influence of Fuel and Condition in Combustion Synthesis on Properties of Copper (II) Oxide Nanoparticle

Copper oxide nanoparticles have been received attraction due to their unique properties and potential future applications. In present work nanostructure Copper (II) oxide (CuO) spherical nanoparticle synthesized by solution combustion method and the influence of different fuel and condition on the properties of CuO particle was investigated. Crystalline phase and size indicated by applying XRD and particle size distribution studied further using DLS. Scanning electron microscopy (SEM) was used for morphological study and EDAX analysis shows composition of CuO particles. Nanostructure of copper (II) oxide particle studied further by Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) applied for detail study on crystalline structure of particles.

Nonequilibrium plasma-chemical synthesis of nanosized particles of metal oxides

The results of investigation into the synthesis conditions and basic characteristics of nanoparticles of titanium dioxide and the mixed oxide (TiO2)x(SiO2)1−x from a gaseous mixture of oxygen, hydrogen, and titanium tetrachloride (or a mixture of titanium and silicon tetrachlorides) are reported. The synthesis was initiated by a pulsed electron beam and was a chain process in character. The geometric dimensions of oxide particles were measured and their X-ray diffraction, X-ray fluorescence, and IR spectrometric studies were performed. It was shown that the nonequilibrium character of the synthesis process induced by a pulsed electron beam allowed the temperature threshold for the formation of the crystalline structure of particles to be lowered.

Preparation of nanostructured Zn–Cr–O spinel powders by ultrasonic spray pyrolysis

Ultrasonic spray pyrolysis (1.7 MHz) has been applied for the generation of zinc chromium oxide submicronic (470 nm) particles from the corresponding metal nitrate solution. Heterogeneous gas–liquid/solid chemical reactions occurred in dispersed systems (aerosols) at 1173 K with the residence time ranging from 3 to 6 s. Such a synthesis method enables a high surface reaction and stoichiometric retention at the droplet scale that is of special importance when functional materials with sensing properties are considered. Consequently, homogeneous distributions of the constituting elements and zinc to chromium atomic ratio of about 0.7 are proved by EMAX analysis. The particle morphology, revealed mostly as a composite structure, comprised of primary crystallites smaller than 70 nm. The particle crystalline structure, phase content and decomposition behavior were analyzed in accordance with various methods of analysis (X-ray powder diffraction (XRD). differential scanning calorimetry (DSC). differential thermal analysis (DTA), scanning electron microscopy with X-ray microanalyser (SEM–EMAX)) and discussed in terms of precursor chemistry and process parameters.

Probing the structure of solids in a liquid environment: a recent in-situ crystallisation experiment using high energy wavelength scanning X-ray diffraction

Structural development associated with the crystallisation of n-eicosane is probed in-situ, using high energy wavelength scanning X-ray diffraction (HEWSXRD) at the synchrotron radiation source at HASYLAB, Germany. Preliminary data reveal confirmatory evidence for an undefined structural phase transformation close to the melting point, which is probably related to increased molecular disordering as a function of temperature. The experiment confirms that information on the structure of crystalline particles can be obtained in-situ as they form.

Structure of particles of very finely divided electrolytic iron

X-ray structural analysis and electron microscopy have been employed to study the sizes and crystalline structures of particles of very fine iron powders produced in a two-layer bath using direct and pulsed currents and in a bath with an ultrasound-emitting cathode. The study has demonstrated that the superposition of an additional perturbance (an ultrasonic field or a pulsed current supply) on the electrolysis process restricts the growth of microcrystals and decrease their size variation compared with particles produced by electrolysis using a direct current. The character of curves of some structural characteristics of very fine iron powders plotted against the parameters of electrolysis in a two-layer bath with the use of a direct current, an ultrasound emitting cathode, and a pulsed current is evidence that iron particle formation in these variants of the electrolytic process occurs through different mechanisms.