Turbulence damping above the cloud height in suspensions of concentrated slurries in stirred tanks

Poor mixing in the clear liquid layer above the cloud height has been reported by several authors. This study uses LDV measurements to quantify turbulence above the cloud using a liquid level of 1.5 T to remove the barrier of a free surface at H = T. A D = T/3, down-pumping PBT was used at an off-bottom clearance of C = T/3. Three slurries were tested at impeller speeds 0.8, 1, and 1.2N_js. The change in turbulence was quantified using the normalized root mean square (RMS) of the fluctuating velocity summed and averaged over each radial traverse. A significant difference between the fluctuating values of the cloud height—minimum, average, and maximum—was observed. The turbulence decays until the maximum cloud height. Beyond that, it remains constant and near zero. The effects of both particle size and solids concentration prove to be important.     

Fatty Acid Composition and Trans Fatty Acids in Crisps and Cakes in Turkey's Markets

In this study, trans fatty acid and fatty acid composition of 57 crisps and 50 cakes sold in the markets in Turkey were determined. C 18:1, oleic acid, was the major fatty acid in all crisps and cake samples. The percentages of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) ranged between 27.98–46.57, 35.73–47.57, and 9.86–35.90 g/100 g fatty acids in crisps and 35.41–54.03, 25.89–44.87, and 10.52–26.97 g/100 g fatty acids in cakes, respectively. Total trans fatty acids ranged from 0.02 to 1.35 g/100 g fatty acids in crisps and 0.00 to 5.05 g/100 g fatty acids in cakes, respectively.     

Fabrication of oriented electrospun cellulose nanocrystals–polystyrene composite fibers on a rotating drum

Nitrobenzene (CNC-1), trifluoromethyl benzene (CNC-2) modified and polystyrene-grafted (CNC-g) cellulose nanocrystals in polystyrene (PS)-N,N dimethylformamide (DMF) solutions were electrospun and collected as stretched and aligned fibers on a rotating drum. Scanning electron microscope pictures showed significant alignment in the case of unmodified and nitrobenzene-modified CNC-1/PS nanocomposite fibers once the linear speed of rotor reached to 15 m s⁻¹. Fiber diameter decrease was more strong with rotor speed increase in the case of trifluoromethyl benzene modified (CNC-2) and polystyrene-grafted (CNC-g) cellulose nanocrystals/PS systems. Dynamic mechanical analysis including storage and elastic modulus of electrospun-oriented fibers were performed on surface-modified and polymer-grafted CNC/PS samples. According to α transition peak, the increase in the glass-transition temperature with filler concentration was the highest in polymer-grafted CNC-g/PS composite fibers. It was due to the interpenetration of grafted polymer brushes and free polymer chains in continuous phase and resulted in restrictions of motions of polymer chains in the PS matrix. The elastic moduli of nitrobenzene (CNC-1) and trifluoromethyl benzene (CNC-2)-modified CNC-filled PS composite fibers agreed well with percolation model, which indicates the CNC–CNC interactions and network formation with an increase in concentration. Magnitude of the elastic modulus of polymer grafted CNC-g at 0.33 vol % in PS was significantly higher than the prediction from percolation theory. It was due the immobilized polymer chains around CNC-g particles. However, grafted polymer chains, at higher CNC concentrations acted like stickers among CNC particles and caused CNC agglomerates with entrapped free polystyrene from the matrix, thus caused a decrease in the elastic modulus. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48942.     

Investigation of Magnetic Properties of Phase Transformations in Copper-Based Alloys

In this study, the magnetic properties of both Cu_85.41Al_9.97Mn_4.62 and Cu_82.41Mn_13.81Al_3.78 (wt%) shape memory alloys were studied. The analysis of the magnetization as a function of applied field and temperature was conducted between ?10 to 10 T magnetic field ranges at constant temperature. Two alloys were examined using ac magnetic susceptibility measurements. The magnetic saturation values at room temperature were found to be approximately 1 and 70 emu/g for Cu_85.41Al_9.97Mn_4.62 (wt%) and Cu_82.41Mn_13.81Al_3.78 (wt%) alloys, respectively. The magnetic saturation and the coercivity values for the CuAlMn alloy are found smaller than those for the CuMnAl alloy. Moreover, from the magnetization curves, the typical ferromagnetic behavior were observed for both alloys. Details of the morphological properties and chemical composition have been examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively.     

Determination of important biochemical properties of honey to discriminate pure and adulterated honey with sucrose (Saccharum officinarum L.) syrup

The aims of the present study were to determine biochemical properties of honey samples and to discriminate pure and adulterated honey produced by the standard bee feeding method (control honey), the shaking method (pure blossom honey), and overfeeding (100 kg/colony syrup) with sucrose syrup (adulterated honey). The biochemical properties evaluated were moisture, ash, acidity, hydroxymethylfurfural (HMF), specific sugars (i.e. fructose, glucose, fructose–glucose, sucrose, and maltose), diastase activity, δ¹³C value (honey), δ¹³C value (protein), electrical conductivity, potassium, vitamin C, and proline. Fifteen honey samples were analyzed by discriminant analysis stepwise method. Proline, electrical conductivity and sucrose were found as discriminative characters of samples. Based on these three properties 100% of original group cases (samples) correctly classified in their real group. We found that the honey produced by feeding with 100 kg sucrose syrup per colony contained the sucrose as low as pure blossom honey. Therefore, the sugar (sucrose, fructose and glucose) content of honey cannot be used to distinguish between adulterated (sucrose syrup) and pure blossom honey.     

Quantification of Market Performance as a Function of System Security

The tight coupling between market and system operations in the restructured environment requires a thorough understanding of the interdependence between the market performance and the way the power systems are operated. In particular, we need to go beyond the qualitative characterization and to quantify the dependence of the market performance on the system security. Such studies are typically not performed in today's regional transmission organization, or RTO, structures. In this paper, we develop a general approach to quantify the monetary impacts of complying with a specified security criterion when the deployment of appropriate preventive and/or corrective security control actions is fully taken into account. This approach is deployed in the day-ahead electricity markets and is based on the emulation of the way the RTO currently operates the market and the grid, the latter in compliance with the security criterion. The proposed approach has a wide range of applications such as comparative market performance assessments of different security criteria and the cost/benefit analysis of network improvements to mitigate the market performance impacts of a set of specified contingencies. We illustrate the application of the proposed approach on the large-scale ISO-NE system to quantify the monetary impacts associated with changing from the current security criterion to two other criteria using the actual 2005 day-ahead data-the historical system model and the bids/offers submitted-with the actual market clearing methodology. These studies capture, in a meaningful way, the impacts of the changes with respect to the current security criterion. An important finding of this study is that the economic efficiency of electricity markets need not decrease when the system is operated under a stricter criterion.     

A Benchmark for Some Physical Properties of Zinc-Blende ZnS

Somephysical properties of zinc-blende polytype of ZnS were investigated via geometry optimization calculations. After employing a shell model interatomic potential to our computations, some physical parameters such as typical cubic elastic constants, young modulus, shear modulus, bulk modulus, poisson ratio, elastic wave velocities, static and high frequency dielectric constants, and static refractive index zinc-blende ZnS were deduced. Later, previous theoretical results and our current results with each other as well as with former experimental findings were evaluated. Present results exhibit a fair consistency with experiments and better than those of several recent density functional theory results for the considered parameters of related material.     

High resolution spherical microwave holography

A practical technique is developed to determine the electric and/or magnetic field on objects and sources inside a spherical measurement surface. The technique, known as spherical microwave holography (SMH), provides a nondestructive, nonintrusive method of point-by-point evaluation of antennas and radomes over their spatial extent. The resolution capability of SMH is developed and demonstrated by measurements. Resolution in SMH is only limited by the measurement system's capabilities. Dielectric and metallic obstacles on the surface of a radome are located and identified. Resolution as small as 0.33λ₀ is demonstrated