Elucidation of key aroma enhancement in cloudy lemon juices by the addition of peel oil using GC–MS-Olfactometry

Volatile substances play a crucial role in the consumer preference of lemon juices. The effects of heat treatment and addition of lemon peel oil to lemon juice (Citrus limon Burm. cv. Kutdiken) on the aroma compounds were elucidated for the first time. Total phenolic, antioxidant activity, acidity, pH and colour properties were also studied. Results revealed that the aroma of the juice samples comprised mostly the terpene compounds. Limonene, γ-terpinene, β-pinene and α-pinene were the influential terpenes responsible for the distinctive odour of the lemon juice. The addition of the lemon peel oil increased the amounts of the aroma and aroma-active compounds. Besides, the heat treatment had a positive effect on the total phenolics and the antioxidant activity but it caused significant reduction of the aroma compounds. Sensory analysis revealed that the most preferred sample was the juice with lemon peel oil added after pasteurisation.     

A Hybrid Solar Absorber–Electrocatalytic N‐Doped Carbon/Alloy/Semiconductor Electrode for Localized Photothermic Electrocatalysis

Converting and storing intermittent solar energy into stable chemical fuels of high efficiency depend crucially on harvesting excess energy beyond the conventional ultraviolet light spectrum. The means of applying highly efficient solar–thermal conversion on practical electricity‐driven water splitting could be a significant stride toward this goal, while some bottlenecks remain unresolved. Herein, photothermic electrocatalytic oxygen and hydrogen evolution reactions are proposed, which bestow a distinctive exothermic activation and electrochemical reactivity in a reconstructed electrolyzer system, and which are poised for efficient renewable energy production. Attributed to the synergistic in situ coupling of the N‐doped carbon, metallic alloy and oxides, in view of their broadband light absorption, high electrochemical surface area, and efficient charge transfer attributes, the hybrid photothermal electrocatalytic electrode simultaneously satisfies efficient photon‐to‐heat conversion and augmented electrochemical catalytic activity. Finally, a system level design of an appropriate photothermally mediated electrolytic cell with close‐proximity light‐illumination window along with a low‐thermal‐emittance electrolyte separator that preserve an overall large localized thermal gradient and efficient mass transport is devised. Such a photothermally mediated electrocatalytic system presented here may open up new avenues for the development of solar–thermal energy utilization in other forms.     

Alkyd resins based on waste PET for water-reducible coating applications

Simultaneous glycolysis and neutral hydrolysis of waste PET flakes obtained from grinding post-consumer bottles was carried out in the presence of xylene and an emulsifier at 170 °C. The product was separated from ethylene glycol (EG), water, and xylene by filtration, and was extracted by water at boiling point thrice. The remaining solid was named water insoluble fraction (WIF). The filtrate was cooled to 4 °C, and the crystallized solid obtained by filtration was named water soluble crystallizable fraction (WSCF). These fractions were characterized by acid value (AV) and hydroxyl value (HV) determinations. WSCF and WIF were used for preparation of the water-reducible alkyd resins. Three long oil alkyd resins were prepared from phthalic anhydride (PA; reference alkyd resin) or depolymerization product of the waste PET (PET-based alkyd resin), glycerin (G), fatty acids (FA), and glycol (EG; reference alkyd resin) or depolymerization product of the waste PET (PET-based alkyd resin). Film properties and thermal degradation stabilities of these alkyd resins were investigated. Physical properties (drying times and hardness) and thermal degradation stabilities of the PET-based alkyd resin is better than these properties of the reference alkyd resin.     

Comparison of the mechanical,thermomechanical, thermal,and morphological properties of pumice and calcium carbonate‐filled poly(phenylene sulfide) composites

In this study, it was aimed to investigate the mechanical, thermal, thermomechanical, and morphological properties of pumice and calcium carbonate (CaCO₃)‐filled poly(phenylene sulfide) (PPS) composites and compare the effect of these filler materials on the properties of composites. Mechanical test results indicate that %1 pumice and CaCO₃ addition increased the tensile strength value of PPS. With the %1 loading level of pumice, tensile strain of composites remained unchanged, but for other loading levels of both fillers, tensile strain of composites decreased. Hardness of composites increased with the addition of pumice to PPS matrix for all loading levels of pumice. The lowest damping factor peak intensity was observed for %1 pumice included composites. Morphological analyses results revealed that pumice particles are clearly embedded in the PPS matrix and covered with matrix. On the other hand, there are a number of microvioids that can be observed in the tensile fracture surfaces of CaCO₃‐filled composites. POLYM. COMPOS., 37:3160–3166, 2016. © 2015 Society of Plastics Engineers     

Teaching with concrete and abstract visual representations: Effects on students' problem solving, problem representations, and learning perceptions.

In 3 experiments, we examined the effects of using concrete and/or abstract visual problem representations during instruction on students' problem-solving practice, near transfer, problem representations, and learning perceptions. In Experiments 1 and 2, novice students learned about electrical circuit analysis with an instructional program that included worked-out and practice problems represented with abstract (Group A), concrete (Group C), or abstract and concrete diagrams (Group AC), whereby the cover stories were abstract in Group A and concrete in Groups C and AC. Experiment 3 added a 4th condition (C-A) with a concrete cover story and abstract diagrams. Group AC outperformed Groups A and C on problem-solving practice in Experiments 1 and 2 and outperformed Group C on transfer across the 3 experiments; Group AC also outperformed Group C-A in Experiment 3. Further, Group A outperformed Group C on transfer in Experiments 2 and 3 and outperformed Group C-A in Experiment 3. Transfer scores were positively associated with the quality of the diagrams and the number of abstract representations drawn during the transfer test. Data on students' learning perceptions suggest that the advantage of Group AC relies on the combined cognitive support of both representations. Our studies indicate that problem solving is fostered when learners experience concrete visual representations that connect to their prior knowledge and are enabled to use abstract visual representations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Polybutylene Succinate (PBS) – Polycaprolactone (PCL) Blends Compatibilized with Poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) Copolymer for Biomaterial Applications

This study reports the preparation and characterization of Polybutylene Succinate (PBS)-Polycaprolactone (PCL) melt blends (10–40 wt.% PCL) in the presence of a compatibilizer, in order to explore their potential use as a biomaterial. The thermal transitions, as well as the crystallinity of the polymer blends were analyzed by Differential Scanning Calorimetry, the thermomechanical properties were analyzed via Dynamic Mechanical Analysis and phase morphologies were characterized by Scanning Electron Microscopy. Degradation profiles of the blends were analyzed in PBS buffer solution at pH 7.4 at 37°C via pH measurements. Cytotoxicity of the PBS/PCL films were tested by MTS assay.