Mesoporous titania nanoparticles as photocatalyst for degradation of 2-chlorophenol

Mesoporous titania nanoparticles (MTN) was successfully prepared by microwave-assisted menthod. The performance of MTN was compared with degussa P25 (commercial TiO2) on photocatalytic degradation of 2-chlorophenol (2-CP). Both catalysts were characterized by XRD, FTIR, UV-Vis DRS and surface area analysis. The characterization data indicated that MTN has higher surface area and lower particle size than P25. The 2-CP was successfully degraded completely under UV light irradiation despite of having a slightly higher band-gap value compared with P25. This study demonstrated that MTN shows a good potential as a photocatalyst.

Valorisation of brewers’ spent grain in different particle size in yogurt production

The potential of brewers’ spent grain (BSG) as a functional food ingredient has been investigated for having high nutritional value. A high amount of dietary fiber of BSG shows a high ability to bind water; thus, it tends to solidify food mixture. This characteristic has a beneficial effect in the utilization of BSG as a filler and texturizer in yogurt. The study aims to evaluate the impact of the BSG addition in yogurt production and its quality. BSG was prepared in three different particle sizes, and an amount of 10% was added for yogurt fermentation. The impact of BSG addition was evaluated after 24 h of storage. The result shows that different particle sizes of BSG had no significant impact on pH and syneresis, while it significantly affected the amount of lactic acid and countable S. thermophilus. However, BSG increased the fermentation rate of yogurt, and had a positive impact on water holding capacity. A lower particle size had a higher amount of lactic acid and a lower S. thermophilus. The lower particle size lowered the lightness of the yogurt. Rheological analysis showed that a higher particle size of BSG increased the shear stress and viscosity of yogurt.

Different limestone particle sizes for soil acidity correction, Ca and Mg supply and corn yield

The aim of this study was to evaluate the soil acidity correction and the grain yield responses for the lime application in different granulometric particles. The limestone particle sizes incorporated into the distroferric red Oxisol were: 0.20 mm to 0.30 mm; 0.30 mm to 0.56 mm; 0.56 mm to 0.82 mm and 0.82 mm to 2.00 mm, at doses of 1.3 t ha-1; 2.6 t ha-1; 3.9 t ha-1 and 6.6 t ha-1 respectively, and a control respectively, and a control (no lime incorporation in the soil). The soil chemical characteristics pH, H+Al3+, Al3+, Ca2+ e Mg2+ were evaluated at 6 months and 18 months after the lime application. The corn yields were evaluated during the 2008/2009 and 2009/2010 crop years. Higher limestone contents and lower particle size resulted in the same effect on soil acidity correction, reducing Al3+ and increasing Ca2+ and Mg2+ in the soil when the 0.30 mm limestone was incorporated, with residual effect at 18 months. Highest corn yield was obtained when the 0.82 mm to 2.00 mm particle size was incorporated in the first crop year, when compared to the lowest limestone particle size used.

Sol-Gel Synthesis of Bioglasses: A Growth Kinetics Study by Dynamic Light Scattering

In this work, the nucleation of bioglasses particles was approached through Dynamic Light Scattering in order to analyze how different synthesis parameters influence on the particle growth. It was evaluated the following parameters: pH between 10 and 11; surfactant concentration (PEG) between 0 to 20g/L; Three different compositions were chosen based on the 47SiO2-(38 – x)Na2O-(9 + x)CaO-6P2O5 system ( x = 0, 10 and 20). For each experimental condition, the growth kinetics (Kc.t-1) was calculated, and the obtained values were analyzed by factorial design of experiments. The results evidence that higher pH, higher surfactant concentration and lower Na/Ca ionic ratio lead to lower values growth kinetics in which, in turn, are associated with lower particle size.

Physicochemical colourants effects on polymeric composites printing toner

Purpose – This paper aims to report on production of the colour digital printing toners cyan, magenta and yellow. Colour digital electrophotographic printing is currently in high demand. The provision of a large colour gamut depends on appropriate selection of precise colourants to produce toner capable of producing a thin layer on paper. Design/methodology/approach – Printing toners were synthesised by the emulsion aggregation method, and then evaluated for chemical constitution and effects of the colourant substituents. Findings – Results demonstrated that increasing the polarity of a pigment produced better dispersion and lower particle size with narrower distribution and even better colour reproduction. While, changing a pigment’s characteristics did not affect the toner shape or its thermal properties. Practical implications – The developed method provides a simple way to synthesise colour printing toner. Social implications – Emulsion aggregation toners provide less hazardous materials during printing. Originality/value – Evaluations of the influence of solid-state parameters and physicochemical properties of the pigments on printing toner characteristics were done for the first time.

Investigation of Particle Size Effects on the Magnetic Properties and Corrosion Behaviour of Mechanically Alloyed Nd-Fe-B Powder

Elemental powders of Nd, Fe and B were mechanically alloyed using a planetary ball mill. The change of structure and particle size was examined. XRD pattern revealed that with prolong milling, the mixture of the powders was transformed to nearly amorphous state. Smaller particle size was observed with prolong milling. Magnetization of the mixture of powders was studied using AGM. The saturation magnetization of the mixture was observed to increase initially and then decrease with increasing milling time. The reduction of the magnetic properties was suspected to be due to surface damage which was incurred by extensive milling. The corrosion rate was observed to be higher for larger particle size (low milling time). This indicated higher mass gain percentage of larger particle size compared to lower particle size. The magnetic properties however, did not should any significant improvement after corrosion effect.

The role of compactibility in liquid–solid separation of wastewater sludges

The dewaterability of sludges is generally evaluated by the measurement of specific resistance to filtration (SRF) and capillary suction time (CST). It is generally, but not truly, agreed that the lower figures of these parameters indicate the easiness of sludge dewatering. The biological sludges which have the lower particle size and EPS contents may be characterised as hard-to-filter sludges based on SRF and CST measures. However, cake solids concentration of such a kind of sludge can be unexpectedly higher when the centrifugation is used as the dewatering mechanism. This study introduces compactibility, which is cake solids concentration of sludges after centrifugation as a new measure of dewaterability of hard-to-filter sludges. The results of this study claim that although the filterability indexes (CST and SRF) are moderately high for hard-to-filter sludges, their compactibility might be high indicating particle packing characteristics.

Lorentz Microscopy and Electron Holography of Nanocrystalline Magnetic Materials

ABSTRACTThis paper employs an analytical model for the phase shifts imparted on a beam electron by a spherical particle with a uniform magnetization. Model image simulations of Fresnel and Foucault type Lorentz microscopy contrast are presented. Estimates of a lower particle size limit for which no magnetic information can be extracted from the images are given and compared to similar estimates for the electron holography observation method. It is concluded that conventional Lorentz methods have a lower particle size limit of around 30 nm (for cobalt particles), while electron holography can be used to even smaller sizes.

Comparing Particle Counters: Cost vs. Reproducibility

Particle counters are used in evaluating particle concentrations in liquids and gases and on surfaces. Even for the same purpose, several types are commercially available. Many factors will go into a decision about which to buy. These include upper and lower particle size detection limits; particle size subdivisions; data display, communication, and analysis capabilities; ease of use; reliability; accuracy; reproducibility (precision); and cost. A method is presented to allow comparisons based on reproducibility of measurements and cost.