Extraction and identification of anthocyanin from purple corn (Zea mays L.)

An efficient extraction of anthocyanin from purple corn (Zea mays L.) was investigated in this paper. Tristimulus colourimetry was used to evaluate the process quantitatively and qualitatively. Purple corn anthocyanin was extracted with 1 n HCl–95% ethanol (15:85, v/v) at different extraction temperatures (30–70 °C), times (60–120 min) and solid–liquid ratio (1:20–1:40). The combined effects of extraction conditions on anthocyanin yield and colour attributes were studied using a three‐level three‐factor Box–Behnken design. The results showed that the highest yield of anthocyanin from purple corn (6.02 mg g^?1) were obtained at 70 °C, extraction time 73 min, and solid–liquid ratio 1:25. Three kinds of non‐acylated anthocyanins were detected and characterised as cyanidin‐3‐glucoside, pelargonidin‐3‐glucoside and peonidin‐3‐glucoside by HPLC‐MS.     

Rostering in a rail passenger carrier

In this paper we present an applied study, commissioned by the regional rail passenger carrier EuskoTren, into how the annual workload of drivers can be allocated in an egalitarian fashion. The allocation must meet the constraints arising from working conditions and the preferences of employees, as reflected in collective bargaining agreements. The workload varies over the five periods, into which the year is divided, and according to the day of the week. Moreover, not all morning, evening and night shifts are of equal duration. Reduced services on public holidays are also considered. The solution to the problem proposed is obtained in four linked steps, at each of which a binary programming problem is solved using commercial software. Step one is to build five lists of weekly multi-shift patterns, two of them rotating, that contain all the shifts in the week. Step two consists of the partially rotating annual assignment of patterns to drivers, step three involves the extraction of shifts by reduction of services on public holidays, and step four incorporates the durations in hours into the shifts already assigned. The final solution obtained is quite satisfactory: all drivers are assigned a similar number of morning, evening and night shifts and Sundays off, and they work practically the same number of days and hours per year. The results obtained, the adaptability of the system to new requirements and the computation time used are fully satisfactory to the firm, which has decided to implement the model.     

Surface wettability and spectroscopic studies on miscibility and ion adsorption of binary biomimetic self-assembled monolayers on gold surfaces

Binary self-assembled monolayers (SAMs) have been much studied due to their high applicable potential as a model of biomimetic surfaces. However, the research about miscibility of binary SAMs has not much been investigated yet. In this work, we focused on analyzing the binary SAMs composed of mercaptohexadecanoic acid (MHA)-hexadecanthiol (HDT) on gold surfaces with Cassie equation, Israelachvili equation, and FTIR spectroscopy to confirm that the binary SAMs are well mixed. As a result, MHA-HDT binary SAMs are considered miscible because the result obtained from FTIR spectra is in good agreement with that calculated by Israelachvili equation for the case that two different molecules are well mixed on the surface. Also, the adsorption of cadmium ions on binary SAMs was confirmed by the appearance of carboxylate stretching bands. This article is dedicated to Professor Chang Kyun Choi for celebrating his retirement from the School of Chemical and Biological Engineering, Seoul National University.     

Risk assessment for pipelines with active defects based on artificial intelligence methods

The paper provides another insight into the pipeline risk assessment for in-service pressure piping containing defects. Beside of the traditional analytical approximation methods or sampling-based methods safety index and failure probability of pressure piping containing defects will be obtained based on a novel type of support vector machine developed in a minimax manner. The safety index or failure probability is carried out based on a binary classification approach. The procedure named classification reliability procedure, involving a link between artificial intelligence and reliability methods was developed as a user-friendly computer program in MATLAB language. To reveal the capacity of the proposed procedure two comparative numerical examples replicating a previous related work and predicting the failure probabilities of pressured pipeline with defects were presented.     

Equilibrium liquidus temperatures of binary mixtures from differential scanning calorimetry

The measurements of solid-liquid phase diagrams for a binary mixture using a differential scanning calorimeter are revisited in this paper. A new method employing the DSC curves and a theoretical model to detect solid-liquid equilibrium temperature of the initial mixture before freezing is proposed. The liquidus temperatures for different compositions are found to be in good agreement with the available literature data.     

Modelling and optimisation the efficiency of crystalline silicon PV/T solar panel

In this research, a modelling of photovoltaic/thermal panel is carried out by using COMSOL. Compared to the literature, an ANOVA analysis is developed to find significant factors and interactions on the temperature of cells, electrical and thermal efficiency. From ANOVA analysis, it is found that significant factors are: convective heat coefficient, water velocity and solar power. Their second and third order interactions are also significant. From the test of two levels, it is found that in order to have a better performance of the system, solar power and convective heat coefficient should be at lower level. Optimal operating conditions are found by response surface methodology: the thickness of cells, convective coefficient, fluid velocity and solar power should be, respectively, of 0.04 m, 6.5 W/m²K, 0.5 m/s and 150 W/m². Thermal, electrical and overall efficiency are, respectively, of 69.54%, 12.54% and 82.08%. A mathematical model for the analysed responses is obtained.     

Binary nickel ferrite oxide (NiFe2O4) nanoparticles coated on reduced graphene oxide as stable and high-performance asymmetric supercapacitor electrode material

Transition metal oxides are nowadays one of the most important materials in the manufacture of capacitive electrodes. The most important problems with these materials for applied energy storage devices are low specific energy and poor electrical conductivity. In this research nickel ferrite nanoparticles (NiFe₂O₄) and also hybrid of NiFe₂O₄/rGO are synthesized by hydrothermal method and characterized by XRD, Raman, and XPS analysis. The amount of porosity and specific surface area is studied by BET analysis as and surface morphology is studied by SEM and TEM. To investigate the effect of adding rGO to NiFe₂O₄ nanoparticles, from a hybrid electrode superconducting electrochemical tests are performed, including CV, EIS, and charge-discharge. This electrode with a capacitance of 584.63 F/g and capacitance retention of 91% after 2000 consecutive cycles can be a tempting option for supercapacitor applications.     

Heat-acclimatised strains of Rhodopseudomonas palustris reveal higher temperature optima with concomitantly enhanced biohydrogen production rates

Temperature is a critical parameter for bioprocess performance, requiring careful optimisation for peak efficiency. Green biohydrogen production via photofermentation by purple nonsulfur bacteria including Rhodopseudomonas palustris has been extensively researched, yet realisation is limited by comparatively low productivity. We thus assessed the growth and hydrogen productivity of two closely-related strains of R. palustris acclimated to higher temperatures, revealing markedly increased strain-dependent optima than the 30 °C previously accepted. Strain CGA009 grew 53% faster at 35 °C, with 2.4-fold higher hydrogen production rate, while at 40 °C strain ATH 2.1.37 displayed 86% faster growth and 4-fold higher production rate, along with improved specific production and substrate conversion efficiency. These results reaffirm the necessity of pre-acclimation when verifying temperature optima and expand the feasible temperature range for advancement of high-rate biohydrogen production. Further, the superior heat resistance and production capability of strain ATH 2.1.37 raises the potential for further efficiency gains from thermotolerant environmental isolates.