Infrared thin layer drying of saffron (Crocus sativus L.) stigmas: Mass transfer parameters and quality assessment

Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures(60,70, …, 110 °C). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were determined by using the Dincer and Dost model. The diffusivity values varied from1.1103 × 10~(-10)m~2·s~(-1)to 4.1397 × 10~(-10)m~2·s~(-1) and mass transfer coefficient varied in the range of 2.6433 × 10~(-7)–8.7203 × 10~(-7)m·s~(-1). The activation energy was obtained to be 27.86 k J·mol~(-1). The quality assessment results showed that the total crocin content increased, when the temperature increased up to90 °C but, in higher temperatures, the amount of crocin decreased slightly. The total safranal content of the samples decreased slightly when drying temperature increased from 60 °C to 70 °C and then continuously increased up to 110 °C. Also, the amount of picrocrocin increased from 83.1 to 93.3 as the drying temperature increased from 60 °C to 100 °C.     

Quantitative characterization of carrier injection across metal–organic interfaces using Bardeen theory

We have investigated the contact between a metal and an organic/polymeric (o/p) material and we have introduced a relation for carrier injection using Bardeen theory. A series of narrow barriers is considered in the semiconductor side to account for the localized nature of the carriers in the o/p material. As an application of the model, we have calculated the hopping rate of carriers in terms of the contact parameters. Also, we have discussed the hopping of carriers deep into the organic dielectric. Finally, we have explored the hopping rate in practical contacts between polyfluorene-based polymers and different electrodes.     

Photometric stereo for strong specular highlights

Computational Visual Media - Photometric stereo is a fundamental technique in computer vision known to produce 3D shape with high accuracy. It uses several input images of a static scene taken from...     

Thermal Expansion,Elastic and Magnetic Properties of FeCoNiCu-Based High-Entropy Alloys Using First-Principle Theory

The effects of V, Cr, and Mn on the magnetic, elastic, and thermal properties of FeCoNiCu high-entropy alloy are studied by using the exact muffin-tin orbitals method in combination with the coherent potential approximation. The calculated lattice parameters and Curie temperatures in the face-centered-cubic structure are in line with the available experimental and theoretical data. A significant change in the magnetic behavior is revealed when adding equimolar V, Cr, and Mn to the host composition. The three independent single-crystal elastic constants are computed using a finite strain technique, and the polycrystalline elasticity parameters including shear modulus, Young’s modulus, Pugh ratio, Poisson’s ratio, and elastic anisotropy are derived and discussed. The effects of temperature on the structural parameters are determined by making use of the Debye–Grüneisen model. It is found that FeCoNiCuCr possesses a slightly larger thermal expansion coefficient than do the other alloys considered here.     

Consumer perception of boar meat as affected by labelling information,malodorous compounds and sensitivity to androstenone

This study aimed to assess the influence of two label conditions on the acceptance of boar meat. A central location test was conducted with 145 consumers each assessing 4 pieces of pork loin.     

Cement take estimation using neural networks and statistical analysis in Bakhtiari and Karun 4 dam sites,in south west of Iran

Bulletin of Engineering Geology and the Environment - Water seepage from dam foundations causes reservoir water loss and raises the risk of dam instability. One method of remediation for...     

Enzymatic polymerization of polythiophene by immobilized glucose oxidase

In this study ‘green’, environmentally friendly enzymatic reaction-based synthesis of conducting polymer polythiophene (PTP) is proposed. Glucose oxidase (GO_x) was shown as an effective catalyst, which, in the presence of glucose, produces hydrogen peroxide suitable for the oxidative polymerization of PTP under ambient conditions at neutral pH. Enzymatically induced formation of the PTP layer over GO_x-modified graphite rod electrode (GRE) was demonstrated and evaluated amperometrically and by attenuated total reflectance – Fourier transform infrared (ATR-FTIR) spectroscopy. Surface morphology of GO_x- and PTP-modified GR electrodes was characterized by atomic force microscopy. It was clearly shown that the apparent kinetic Michaelis constant (K_M(app.)) of GO_x/PTP-modified GRE increased by increasing the duration of polymerization reaction. Therefore, enzymatic polymerization could be applied in adjustment and/or tuning of K_M(app.) and other kinetic parameters of GO_x-based electrodes used in biosensor design.     

Synthesis and dissolution behavior of nanosized silicon and magnesium co-doped fluorapatite obtained by high energy ball milling

Nanosized hydroxyapatite (HA) powders exhibit a greater surface area than coarser crystals and are expected to show an improved bioactivity. In addition, properties of HA can be tailored over a wide range by incorporating different ions into HA lattice. The aim of this study was to prepare and characterize silicon and magnesium co-doped fluorapatite (Si–Mg–FA) with a chemical composition of Ca_9.5Mg_0.5 (PO₄)_5.5(SiO₄)_0.5F₂ by the high-energy ball milling method. Characterization techniques such as X-ray diffraction analysis (XRD), Fourier transformed infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) were utilized to investigate the structural properties of the obtained powders. Dissolution behavior was evaluated in simulated body fluid (SBF) and physiological normal saline solution at 37 °C for up to 28 days. The results of XRD and FTIR showed that nanocrystalline single-phase Si–Mg–FA powders were synthesized after 12 h of milling. In addition, incorporation of magnesium and silicon into fluorapatite lattice decreased the crystallite size from 53 nm to 40 nm and increased the lattice strain from 0.220% to 0.296%. Dissolution studies revealed that Si–Mg–FA in comparison to fluorapatite (FA), releases more Ca, P and Mg ions into SBF during immersion. 175 ppm Ca, 33.5 ppm P and 48 ppm Mg were detected in the SBF containing Si–Mg–FA after 7days of immersion, while for FA, it was 75 ppm Ca, 21.5 ppm P and 29 ppm Mg. Release of these ions could improve the bioactivity of the obtained nanopowder. It could be concluded that the prepared nanopowders have structural properties such as crystallite size (~40 nm), crystallinity degree (~40%) and chemical composition similar to biological apatite. Therefore, prepared Si–Mg–FA nanopowders are expected to be appropriate candidates for bone substitution materials and also as a phase in polymer or ceramic-based composites for bone regeneration in tissue engineering applications.     

Combustion of oil palm stone in a pilot-scale fluidised bed reactor

Biomass is being generated in vast amounts from oil palm plantations particularly in developing countries such as Malaysia, Thailand and Indonesia. Oil palm stone (OPS) is currently considered a waste material and has not previously been considered for energy purposes. The main objective of this study was to investigate the thermochemical conversion of OPS in a pilot-scale fluidised bed combustor. The net heating value of OPS was 24.93 MJ/kg. The effect of primary air flowrate and initial bed temperature were the main parameters investigated. The bed and bed's surface temperature were found to decrease as the primary air flowrate increased. In all tests CO emissions were less than 0.2%. The emissions of SO₂ and HCl ranged from 0.02 ppm to 0.05 ppm, significantly below the permitted levels set by legislation. Stable combustion was observed at a bed temperature of 950 °C. The most abundant elements found in the ash were Al, Ca, Fe, K, Mg, Mn, P, S and Si. However, due to the temperature regime used in the study fouling would not be an issue.