Inertial microfluidics for continuous particle filtration and extraction

In this paper, we describe a simple passive microfluidic device with rectangular microchannel geometry for continuous particle filtration. The design takes advantage of preferential migration of particles in rectangular microchannels based on shear-induced inertial lift forces. These dominant inertial forces cause particles to move laterally and occupy equilibrium positions along the longer vertical microchannel walls. Using this principle, we demonstrate extraction of 590 nm particles from a mixture of 1.9 μm and 590 nm particles in a straight microfluidic channel with rectangular cross-section. Based on the theoretical analysis and experimental data, we describe conditions required for predicting the onset of particle equilibration in square and rectangular microchannels. The microfluidic channel design has a simple planar structure and can be easily integrated with on-chip microfluidic components for filtration and extraction of wide range of particle sizes. The ability to continuously and differentially equilibrate particles of different size without external forces in microchannels is expected to have numerous applications in filtration, cytometry, and bioseparations.     

Improvement of the quality of gluten‐free sponge cake using different levels and particle sizes of carrot pomace powder

In this study, carrot pomace powder (CPP) with particle sizes of 210 μm (CPP210) and 500 μm (CPP500) was added in the gluten‐free sponge cake recipe. Flour (rice and corn flour, 1:1, w/w) was replaced with 0, 10, 20 and 30% CPP. With increasing the level and particle size of CPP, batter density, viscosity, consistency and firmness increased. The control cake had a dense, hard texture, irregular shape and low sensory scores. These properties improved with addition of CPP so that the cake density, hardness and cohesiveness reduced, while symmetry index and sensory scores increased. Varying the particle size of CPP had no considerable effects on most of the batter and cake properties, while increasing the level of CPP had great positive effects on the quality of batter and cake. Overall, addition of 30% CPP with either of the particle sizes resulted in an acceptable gluten‐free cake.     

Physicochemical properties of cross-linked-annealed wheat starch

Starch in its native form, may not be able to provide functional properties such as high or low temperatures and shear forces bearings expected in modern industries. Therefore, it is usually modified to make it compatible for different applications. The main aim of this research was to study the effects of dual modification using cross-linking and annealing on physicochemical properties of wheat starch. Therefore, starch was first cross-linked using different levels of POCl₃ (0, 0.1, 0.2, 0.4?%, w/w, starch basis) and then annealed at 40?°C for 72?h. Scanning electron micrographs showed the presence of some spots on the granules of the dual-modified samples. The results of differential scanning calorimetry showed that the onset, peak and conclusion temperatures and enthalpy increased upon dual modification. The X-ray diffraction pattern of the modified samples remained unchanged while water solubility and swelling decreased. The results of rapid visco analyzing showed lower peak, setback, breakdown and final viscosities for the dual-modified samples. These samples produced stronger gels as determined using a texture analyzer. In total, annealing of the cross-linked starch could enhance some of its functional properties for further applications.     

Physicochemical assessment of fresh chilled dairy dessert supplemented with wheat germ

Wheat germ is an available and economical source of protein, vitamins and antioxidants with an increasing application in food products. The main aim of this study was to investigate the effects of different levels (0.0, 2.5, 5.0, 7.5 and 10.0%) and particle sizes (120, 210 and 354 μm) of wheat germ on physicochemical properties of fresh chilled dairy dessert. With increasing wheat germ level, dry matter of the dessert increased while the pH decreased. Particle size had no significant effect on these parameters. Increasing the wheat germ content and particle size enhanced darkness, hardness, cohesiveness and gumminess of the desserts while decreasing springiness and water release of the samples. Wheat germ level had greater effects on different quality aspects of the desserts than its particle size. The most acceptable dessert was produced with no more than 5.0% wheat germ with either of the particle sizes used in this study.     

Structural changes and stress relaxation behavior of κ‐carrageenan cold‐processed gels: Effects of ultrasonication time and power

Ultrasound has been used for cold gelation of κ‐carrageenan hydrocolloid. In this work, the effect of ultrasound conditions such as power (50–150 W) and time (20–240 s) of sonication has been investigated. The application of ultrasound to hydrocolloid dispersion caused an increase in water solubility. The texture profile analysis test was used in order to evaluate the mechanical properties of gels. Textural parameters of κ‐carrageenan gels, enhanced with increasing sonication time and power up to a certain level (usually 2.5 min) and longer sonication times had negative effects. In addition, intrinsic viscosities of sonicated specimens were measured to investigate the molecular characteristics of all samples. An increase in the process time and power reduced the intrinsic viscosity. The microstructural observation by scanning electron microscope determined that applying power ultrasound on κ‐carrageenan dispersions influenced the formation of gel networks significantly.     

Synthesis,Characterization, and Application of Hybrid Inorganic–Organic Composites (K/Na)ZrSi(R)O<Subscript>x</Subscript>

Hybrid inorganic–organic composites, (K/Na)ZrSi(R)O_x, were synthesized from the hydrolysis of the mixture of zirconium n-propoxide (Zr(OPrⁿ)₄) and 3-glycidyloxypropyltrimethoxy silane (GPTS) in 1:1 mol ratio. The hydrolysis reaction was carried out with 0.1 molar HCl in 150 ml of butanol. Then, the synthesized Zr(OPrⁿ)₄-GPTS-hydrolyzate reacted with KOBu^t and NaOSiMe₃ in 1:1 mol ratio at 40 and 50 °C for 24 h, respectively. After these stages, composites were washed and dried under vacuum. Composites and their oxide prepared at 1250 °C by calcinations were characterized by a combination of powder X-ray diffraction, scanning electron microscope, energy dispersive X-ray, Brunauer–Emmett–Teller analysis, Barrett–Joyner–Halenda analysis, and Fourier transform infrared spectroscopies. These hybrid inorganic–organic composites except oxides were used as catalysts in order to see their activities in the polymerization of ε-caprolactone (ε-CL). This study showed that new composite materials except their oxides were effective catalyst in ε-CL polymerization.     

Functionalized Hybrid Coatings on ABS Surfaces by PLD and Dip Coatings

It is important to give water-repellent and antibacterial properties to the acrylonitrile butadiene styrene (ABS) surfaces of the hearing aids. In this study, the sol–gel Si and sol–gel Ti solutions were prepared from the reactions of silicon ethoxide, titanium butoxide and methacrylic acid. The catalyst and Dynasylan F8815 were added to the sol–gel solutions to give hydrophobic properties onto the ABS surfaces. Additionally, silver nanoparticles were synthesized by nanosecond laser and added to the coating solutions to give extra antibacterial properties. The surfaces of the ABS targets were coated using the sol–gel dip coating and pulsed laser deposition techniques. The coatings with good adhesion between film and substrate and good water-repellent properties were achieved. The average contact angles for the coated ABS surfaces were measured in the range between 120 and 125 degrees. The obtained sol–gel materials and produced thin films onto the ABS surfaces were also analyzed in terms of the antibacterial properties. The highly antibacterial properties were observed in the sol–gel solutions and the thin films.