Search results for " Thermal"
showing 10 items of 492 documents
Stability and extraction of bioactive sulfur compounds from Allium genus processed by traditional and innovative technologies
2017
Abstract Since ancient times, species from the Allium genus have been used in both culinary and medicinal applications. The health promoting properties, with well documented “evidence-based” studies, were attributed to the genus’ high content of bioactive organosulfur compounds. For these reasons, the organosulfur compounds have attracted interest in both food and pharmaceutical industries to be used as additives or supplements. Therefore, improvement in the extraction and stability during processing and storage of these molecules is crucial. The presented review documents the effects of traditional and innovative processing techniques on the extraction and stability of organosulfur compoun…
Effects of ultrasound and high pressure on physicochemical properties and HMF formation in Turkish honey types
2018
Abstract In industrial production, thermal processing of honey at 50 °C commonly induces liquefaction, i.e. it reduces the crystal count and viscosity and delays any subsequent crystallization. Unfortunately, thermal treatment can generate toxic 5-hydroxymethylfurfural (HMF), thereby resulting in quality reduction. Considering this, the present work aims at evaluating the influence of (two) processing technologies as alternatives to thermal processing of honey, namely high hydrostatic pressure (HHP; P = 220–330 MPa, T = 50/60 °C, t = 23/106 min), and ultrasound processing (US; at 24 kHz). The quality parameters evaluated for honey included liquefaction time, HMF content, diastase number, co…
Effect of Polyhydroxyalkanoate (PHA) Concentration on Polymeric Scaffolds Based on Blends of Poly-L-Lactic Acid (PLLA) and PHA Prepared via Thermally…
2022
Hybrid porous scaffolds composed of both natural and synthetic biopolymers have demonstrated significant improvements in the tissue engineering field. This study investigates for the first time the fabrication route and characterization of poly-L-lactic acid scaffolds blended with polyhydroxyalkanoate up to 30 wt%. The hybrid scaffolds were prepared by a thermally induced phase separation method starting from ternary solutions. The microstructure of the hybrid porous structures was analyzed by scanning electron microscopy and related to the blend composition. The porosity and the wettability of the scaffolds were evaluated through gravimetric and water contact angle measurements, respective…
Magma and volatile supply to post-collapse volcanism and block resurgence in Siwi caldera (Tanna Island, Vanuatu arc)
2011
Siwi caldera, in the Vanuatu arc (Tanna island), is a rare volcanic complex where both persistent eruptive activity (Yasur volcano) and rapid block resurgence (Yenkahe horst) can be investigated simultaneously during a post-caldera stage. Here we provide new constraints on the feeding system of this volcanic complex, based on a detailed study of the petrology, geochemistry and volatile content of Yasur-Siwi bulk-rocks and melt inclusions, combined with measurements of the chemical composition and mass fluxes of Yasur volcanic gases. Major and trace element analyses of Yasur-Siwi volcanic rocks, together with literature data for other volcanic centers, point to a single magmatic series and p…
Road Thermal Collector for Building Heating in South Europe: Numerical Modeling and Design of an Experimental Set-Up
2022
The combination/integration of renewable energy and storage systems appears to have significant potential, achieving high-energy results with lower costs and emissions. One way to cover the thermal needs of a building is through solar energy and its seasonal storage in the ground. The SMARTEP project aims to create an experimental area that provides for the construction of a road solar thermal collector directly connected to a seasonal low-temperature geothermal storage with vertical boreholes. The storage can be connected to a ground-to-water heat pump for building acclimatization. This system will meet the requirements of visual impact and reduction of the occupied area. Nevertheless, sev…
A Power Sector in Transition Understanding Transition Towards a Cleaner Grid and how Distributed Energy Resources Affect the Design and Operation of …
2018
Important changes in the supply and the demand side of electricity apparatus are now underway, triggered by a combination of drivers dramatically affecting the transmission sector of power systems: greenhouse gas emissions, distributed generation, energy efficiency and the full integration of the European energy market. A variety of accelerating factors - including active consumer, aggregators, energy storage, e-vehicles, etc..- are creating a new era for the many stakeholders, incl. system operators, regional entities, industry and consumer organizations, producers or their trade bodies, Regulators, public decision makers and the society at large. Entraining this background, ENTSO-E and th…
Application of solar energy to seawater desalination in a pilot system based on vacuum multi-effect membrane distillation
2020
Abstract The evaluation of a novel solar seawater desalination system implemented at the University of Almeria (Spain) is presented. It integrates a solar thermal field based on static collectors and a thermal desalination system based on the vacuum multi-effect membrane distillation technology. The distillation unit has a particular innovation to increase its thermal performance, using a seawater flow to condense the steam and preheat the feed. Experiments were made under different environmental conditions to assess the role of the thermal storage system for minimizing the effect of disturbances in solar radiation. Thermal energy could be delivered at a stable temperature to the distillati…
Phase transitions in some n-alkanes and petroleum waxes — investigation by photoacoustic and exoelectron emission techniques
2000
Abstract The use of the photoacoustic (PA) effect and photostimulated exoelectron emission (EEE) technique in the investigation of first- and second-order phase transitions in pure n -alkanes such as n -C 22 , n -C 28 and n -C 32 and in three petroleum waxes having different carbon number distributions, have been examined. Changes in the amplitude and phase of the PA signal with temperature and the temperature dependence of the intensity of photostimulated EEE across the phase transitions have been measured. These measurements have shown that both the polymorphic phase transitions and melting of these hydrocarbons are accompanied by jumps or peaks of the PA amplitude and phase and EEE inten…
Insights into catanionic vesicles thermal transition by NMR spectroscopy
2012
Oppositely charged ionic surfactants can self-assemble into hollow structures, called catanionic vesicles, where the anionic-cationic surfactant pair assumes a double-tailed zwitterionic attitude. In the present work, multilamellar- to-unilamellar thermal transition of a mixed aqueous system of sodium dodecyl sulphate (SDS) and cetyl trimethyl ammonium bromide (CTAB), with a slight excess of the anionic one, has been investigated by 1H, 2H, 14N NMR spectra and 23Na transverse relaxation measurements. It has been inferred that an increase of the temperature enhances the SDS counterion dissociation, which can be considered as one of the driving forces of the mentioned transition. Moreover, in…
Cooperative High-Temperature Spin Crossover Accompanied by a Highly Anisotropic Structural Distortion
2016
Spin transitions are a spectacular example of molecular switching that can provoke extreme electronic and structural reorganizations in coordination compounds. A new 3D cyanoheterometallic framework, [Fe(pz)(Au(CN)2)2], has been synthesized in which a highly cooperative spin crossover has been observed at 367 and 349 K in heating and cooling modes, respectively. Mössbauer spectroscopy revealed a complete transition between the diamagnetic and paramagnetic states of the iron centres. The low-spin-to-high-spin transition induced a drastic structural distortion involving a large one-directional expansion (ca. 10.6%) and contraction (ca. 9.6%) of the lattice. Negative thermal expansion along th…