VLE calculation of carbon dioxide+n-alkanes binary mixtures with MHV2 mixing rule

Vapor-liquid equilibria for binary and asymetric systems include carbon dioxide+C₁-C₈, C₁₀ are calculated by using the Peng-Robinson-Stryjek-Vera equation of state coupled with the modified MHV2 mixing rule. The modified UNIFAC model is used for determining activity coefficient and excess Gibbs free energy. Calculated equilibrium pressures and mole fractions in vapor phase are compared with the experimental data. The average absolute deviation percent (AAD%)s indicates that the error involved in the application of the MHV2 mixing rule by optimized q₁ and q₂ is less than WS and PRSK mixing rules in most cases.     

Thermophysical and rheological properties of liquid egg white and yolk during thermal pasteurization of intact eggs

Thermophysical properties of eggs was studied in a temperature range of 5–60 °C, which could be used to optimize the thermal processing. The effective thermal conductivity of egg white was predicted by Krischer model (f_λ = 0.20), and for egg yolk, parallel model was in good agreement with the experimental data. Power law and Herschel–Bulkley models were used to describe rheological behavior of egg yolk and white, respectively. The differential scanning calorimeter showed that denaturation of white protein starts at 60 °C. Surface heat transfer coefficient increased with increasing temperature. Density decreased during thermal process and was in a good agreement with the predictive models, based on the chemical component.     

Contribution to Shear Wrinkling of GFRP Webs in Cell-Core Sandwiches

Glass-fiber-reinforced polymer (GFRP) cell-core sandwiches are composed of outer GFRP face sheets, a foam core, and a grid of GFRP webs integrated into the core to reinforce the shear load capacity. One of the critical failure modes of cell-core sandwich structures is shear wrinkling, a local buckling failure in the sandwich webs because of shear loading. The shear wrinkling behavior of GFRP laminates with different laminate sequences, stabilized by a polyurethane foam core, was experimentally and numerically investigated. Shear wrinkling was simulated by a biaxial compression–tension setup. The results show that an increasing transverse tension load significantly decreases the wrinkling load. The decreasing effect of tension is explained by the lateral contraction because of Poisson’s effect, which causes an increase in the initial imperfections and subsequent accelerated bending.     

Direct electron transfer from glucose oxidase immobilized on a nano-porous glassy carbon electrode

A pair of well-defined and reversible redox peaks was observed for the direct electron transfer (DET) reaction of an immobilized glucose oxidase (GOx) on the surface of a nano-porous glassy carbon electrode at the formal potential (E°′) of −0.439 V versus Ag/AgCl/saturated KCl. The electron transfer rate constant (k_s) was calculated to be 5.27 s⁻¹. The dependence of E°′ on pH indicated that the direct electron transfer of the GOx was a two-electron transfer process, coupled with two-proton transfer. The results clearly demonstrate that the nano-porous glassy carbon electrode is a cost-effective and ready-to-use scaffold for the fabrication of a glucose biosensor.     

Synthesis of high surface area nanocrystalline MgO by pluronic P123 triblock copolymer surfactant

Nanocrystalline magnesium oxide with high surface area was prepared by a simple precipitation method using pluronic P123 triblock copolymer (Poly(ethylene glycol)-block, Poly(propylene glycol)-block, Poly(ethylene glycol)) as surfactant. The prepared samples were characterized by X-ray Diffraction (XRD), N₂ adsorption (BET), Fourier transform infrared spectroscopy (FTIR), Thermal, differential thermal gravimetric and differential thermal analyses (TG/DTG/DTA) and Scanning electron microscopy (SEM). The obtained results revealed that the addition of surfactant is effective to prepare magnesium oxide with high surface area and affects the morphology of the prepared samples. The results showed that the magnesium oxide calcined at different temperatures ranging from 600 to 800 °C possessed a high surface area in the range of 133.9–78.1 m² g^?1. In addition, the magnesium oxide prepared with the addition of surfactant showed a narrower pore size distribution compared to the sample prepared without the addition of a surfactant.     

A New Criterion for Prediction of Hot Tearing Susceptibility of Cast Alloys

A new criterion for prediction of hot tearing susceptibility of cast alloys is suggested which takes into account the effects of both important mechanical and metallurgical factors and is believed to be less sensitive to the presence of volume defects such as bifilms and inclusions. The criterion was validated by studying the hot tearing tendency of Al-Cu alloy. In conformity with the experimental results, the new criterion predicted reduction of hot tearing tendency with increasing the copper content.     

Chemical Composition and Antibacterial Activity of Essential Oils of Iranian Herbs Against Staphylococcus Aureus Isolated from Milk

Chemical composition and antibacterial activity of essential oils from three endemic plants including, Thymus daenensis Celak, Dracocephalum multicaule Montbr & Auch., Satureja bachtiarica Bunge and one native plant, Tanacetum polycephalum Schultz-Bip were determined. Volatile oils analyzed using gas chromatography and gas chromatography-mass spectrometry. The in-vitro antibacterial activity was performed by agar disc diffusion and micro-dilution assays. The results revealed distinct differences in the compounds depending on sample plant. Among the plant species screened, essential oils of S. bachtiarica and T. daenensis showed highest antibacterial activity against Staphylococcus aureus.     

Data-driven process redesign: anticipatory shipping in agro-food supply chains

Anticipatory shipping uses historical order and customer data to predict future orders and accordingly ship products to the nearest distribution centres before customers actually place the orders. It is a method to meet the increasing customer requirements on delivery service and simultaneously to reduce operational costs. This paper presents a case of anticipatory shipping in the context of agro-food supply chains. The challenge in these chains is the product perishability that leads to product obsolescence in the case of un-balanced supply and demand. This study introduces a data-driven approach that integrates product quality characteristics in data analytics to identify suitable products for anticipatory shipping at the strategic level. It also proposes process redesigns concerning production and transportation at the operational level to realise anticipatory shipping. Finally, using historical data from a Dutch floriculture supplier as input for a multi-agent simulation, the proposed approach and process redesigns are verified. The simulation output shows that anticipatory shipping could increase delivery service level up to 35.3% and reduce associated costs up to 9.3%.     

Investigation of trajectory and rise velocity of loaded and bare single bubbles in flotation process using video processing technique

In flotation, among the key parameters that dictate the hydrodynamic characteristics are bubble rising velocity and trajectory. This study aims to investigate the trajectory and rise velocity of loaded and bare bubbles using an experimental setup and video processing technique. After acquiring the videos of rising bubbles, using the background subtraction algorithm, bubbles were detected and their rise velocity and trajectory were determined with regard to the changes in the coordinates of bubbles’ centers. It was shown that bare bubbles have a zigzag trajectory, while for loaded bubbles the trajectory was close to the straight vertical path. In addition, with increasing bubble size, the rise velocity and the deviation from the straight path increase.