Screening physicochemical,microbiological and bioactive properties of fruit vinegars produced from various raw materials

Food Science and Biotechnology - In the present study, variety of fruit vinegars were investigated in terms of their physicochemical, microbiological and bioactive properties. Total phenolic and...     

Ytterbium (III) oxide reinforced novel TeO2–B2O3–V2O5 glass system: Synthesis and optical,structural, physical and thermal properties

Different samples of xTeO₂.(25-y)B₂O₃.zV₂O₅.yYb₂O₃ (or TBVY) new glass material were synthesized by the classical melt-quenching method. Structural, optical, physical, and thermal analyses of the synthesized glasses were performed in addition to Monte Carlo simulation to test radiation shielding properties. The results showed that increasing ratios of Yb₂O₃ (y = 0.0, 0.5, 1.0, and 1.5 mol%) produced monotonic density values of the synthesized glasses ranging from 4.70058 g cm^?3 to 5.01038 g cm^?3. XRD and FTIR analyses were used to confirm the glass structure of all samples. Optical transmittance and absorption parameters varied almost monotonically with increasing ratios of Yb₂O₃ indicating the ability to predict and control these properties using Yb₂O₃ additive. Furthermore, simulated radiation interaction parameters, such as attenuation coefficients and half-value layer, exhibited well-behaved dependence on the concentration ratio of the Yb₂O₃ additive. This approach to glass material synthesis demonstrate the useful synergetic effect of combining structural, optical, and radiation characteristics.     

Experimental and numerical investigation on particle–particle interaction of multi-particle separation in an alternating and repetitive microchannel

Inertial focusing plays a major role in size-based cell separation or enrichment for microfluidic applications in many medical areas such as diagnostics and treatment. These applications often deal with suspensions of different particles which cause interactions between particles with different diameters such as particle–particle collision. In this study, particle–particle interaction in a laminar flow through a low aspect ratio alternating and repetitive microchannel is investigated both numerically and experimentally. It is revealed that particle–particle collision affects high quality particle focusing. computational fluid dynamics simulations are conducted for demonstrating the effect of the flow field in the transverse cross-section on the focusing quality and position. The experiments and simulations both revealed that if the flow is seeded with a mixture of particles of 3.3 and 9.9 µm diameters, the quality of focusing intensity is degenerated compared to the focusing features obtained by particles with a diameter of 9.9 µm solely. The results clearly show that particle–particle collision between the 3.3 and 9.9 µm particles has a negative effect on particle focusing behavior of the 9.9 µm particles.

     

Structural,physical, and optical characterization of (Nd3+/Eu3+)-doped zinc-rich silica–borate glasses

In this study, zinc–silica–borate glass structures doped with rare earth (RE) oxides Eu₂O₃ and Nd₂O₃ were synthesized with classical melting–quenching technique. 60ZnO–10SiO₂–(30 – x)B₂O₃:xRE (x?=?0, 0.5, 1, 1.5 mol%) composition was chosen as the structure. The doping effect of two different rare earth oxides (individually) at different ratios was investigated according to the structural, physical, and optical properties of the glass structure. Structural properties of the synthesized glasses were determined with Fourier transform infrared (FTIR) device, and densities (ρ) and molar volumes (V_m) of the glasses were measured with Archimedes method, and optical properties were determined with UV–Visible (UV–Vis-NIR) device. FTIR results show that BO₃ units increased in all RE-doped glasses. While densities of the synthesized glasses varied between 3.755 and 3.941 g cm^??3, indirect bandgaps varied between 3.219 and 3.645 eV. The glass with the highest transmittance was the 1% Eu₂O₃-doped glass with a transmittance of 84%. While band edges shifted slightly toward short wavelengths in glasses doped with Nd₂O₃, they shifted to longer wavelengths in glasses doped with Eu₂O₃.

     

A hybrid CDAC-threshold configuring SAR ADC in 28nm FDSOI CMOS

In this paper, a 9-bit 1.3 GS/s single channel SAR ADC is presented. In conventional SAR ADCs, the capacitive DAC size grows exponentially with respect to converter resolution. This results in both signal bandwidth and conversion speed reduction. The proposed architecture implements binary search through a redundant capacitive DAC for the 5 first MSBs and through programmable comparator thresholds for the remaining 4 LSBs. The DAC capacitance at the front-end remains small enough to achieve high sampling rate with increased input bandwidth. Two asynchronously clocked alternate comparators are used additionally to improve conversion speed. The ADC is designed and simulated in 28 nm FD-SOI CMOS. It consumes 4.1 mW from a 1 V supply, while achieving a SNDR of 52.1 dB and a Figure-of-Merit of 11.4 fJ/conversion-step.     

Photocatalytic properties of ZnO nanoparticle coating on porous ceramic substrates with varying porosities produced from fly ash and red mud

In order to improve filtering efficacy, nanoparticles are often deposited as photocatalytic degrading agents onto porous ceramics. This study aimed to deposit ZnO nanoparticles on ceramic substrates produced from fly ash and red mud with adjustable porosity and investigate their photocatalytic properties. To achieve this goal, at first porous ceramics were produced and sintered at various temperature/time intervals. It was observed that sintering at 800°C for 120 min provided a proper structure and porosity. In addition, MgO replacement with MgCO₃ lowered the water absorption of the samples from 25.63% to 11.45%. The samples were then coated with ZnO nanoparticles using the sol–gel method and the ZnO structures obtained were micron-sized plates. It was observed that increasing porosity increased the ZnO amount and accordingly the photocatalytic properties of the products. During the adsorption tests conducted in the dark, the coated ceramic samples were stained with MB with a maximum MB adsorption ratio of ∼14%. On the other hand, no visible MB stain was observed on the samples that were exposed to UV irradiation, and the MB removal after the UV irradiation was 93.6%; therefore, it was concluded that the dominant MB removal mechanism was photocatalytic.     

Thermal fatigue testing of CuCrZr alloy for high temperature tooling applications

CuCrZr alloy offers good mechanical and thermal properties and was investigated in the present work for its potential as tooling material in thixoforming of steels. Samples of CuCrZr alloy were cycled thermally between 450 and 750 °C, every 60 s. The thermal conductivity of the CuCrZr alloy, nearly an order of magnitude higher with respect to that of the conventional hot work tool steel, proved to be very beneficial in terms of thermal stresses generated at the surface upon thermal cycling. The maximum compressive and tensile stresses produced at the front face of the CuCrZr alloy were estimated to be approximately 30 and 10 MPa, respectively, much smaller than those endured by the conventional hot work tool steel. The very favourable thermal stress state in the CuCrZr alloy die was largely negated, however, due to its inferior resistance to high temperature oxidation.     

Experimental Investigation of the Effect of Fire Protection Lobby on Stair Pressurization System in a High-Rise Building

In this study, the stair pressurization system in a 40-storey high office building in Istanbul is investigated through field tests, in order to understand the effect of the presence of a non-pressurized vestibule (fire protection lobby, FPL) before entering the stair at each floor. The building without FPL is simulated by keeping only one of the two doors (of the stair and FPL) open at each floor. This method gave an opportunity to fix other parameters affecting the stair pressurization system and check solely the effect of FPL. Two different cases are taken into account, where the first one (all doors closed) analyses the condition that all stair doors are kept closed and the second one (critical doors are open) is conducted when the stairwell is opened to the floor on a given level (fire floor) and the stair termination door at the discharge floor is kept open. For both cases, the availability of the FPL is investigated by using the aforementioned arrangement. Under the conditions with approximately the same pressurized air flow rate at all doors closed condition, it is found that the availability of FPL increases the pressure difference between the stairwell and the corridor by a factor of approximately 2.2. This is also justified by using empirical formulations available in literature, where this ratio is calculated as 2.0. The results of this study showed that the FPL arrangement improves the effectiveness of pressurization system in a very high-rise building, despite some tolerable drawbacks.     

Intermediate product selection and blending in the food processing industry

This study addresses a capacitated intermediate product selection and blending problem typical for two-stage production systems in the food processing industry. The problem involves the selection of a set of intermediates and end-product recipes characterising how those selected intermediates are blended into end products to minimise the total operational costs under production and storage capacity limitations. A comprehensive mixed-integer linear model is developed for the problem. The model is applied on a data set collected from a real-life case. The trade-offs between capacity limitations and operational costs are analysed, and the effects of different types of cost parameters and capacity limitations on the selection of intermediates and end-product recipes are investigated.