scholarly journals Ανάπτυξη αυτόματων μικρο-τεχνικών προκατεργασίας δείγματος για τον προσδιορισμό μολύβδου και υδραργύρου με συνδυασμένες αναλυτικές τεχνικές

2016 ◽  
Author(s):  
Κωνσταντίνα Μητάνη
Keyword(s):  
Extraction Chamber

Με βάση τα πειραματικά δεδομένα της Διδακτορικής διατριβής προκύπτουν τα παρακάτω:1) Στην πρώτη πειραματική εργασία αναπτύχθηκε μια απλή και γρήγορη μέθοδος για την προσυγκέντρωση και τον προσδιορισμό μετάλλων με τη μικροτεχνική DLLME, σε συνδυασμό με την τεχνική FAAS. Στη μελέτη αυτή χρησιμοποιήθηκε, για πρώτη φορά, ως διαλύτης εκχύλισης, οργανικός διαλύτης ελαφρύτερος του νερού, όπως η DIBK, διευρύνοντας έτσι το σύνολο των διαθέσιμων αποτελεσματικών διαλυτών. Μελετήθηκε και σχεδιάστηκε ένα πρωτότυπο σύστημα προώθησης υγρών, το οποίο επιτρέπει την εν σειρά προώθηση μικρο-ποσοτήτων, διαλυτών ελαφρύτερων του νερού στη FAAS. 2) Στην δεύτερη πειραματική εργασία προτείνεται μια νέα αυτόματη μέθοδος μικροεκχύλισης υγρού -υγρού, το οποίο βασίζεται στην πλατφόρμα «σταγόνα σε έμβολο», χρησιμοποιώντας μια διάταξη SIA-LAV για τον προσδιορισμό μετάλλων σε συνδυασμό με την τεχνική FAAS. Για το σκοπό αυτό, κατασκευάστηκε και βελτιστοποιήθηκε ένας θάλαμος μικροεκχύλισης ροής, ο οποίος προσαρμόστηκε σε μία θύρα της βαλβίδας πολλαπλής επιλογής του συστήματος SIA. 3) Στην τρίτη πειραματική εργασία προτείνεται ένα νέο και ευέλικτο αυτόματο σύστημα εκχύλισης υγρού-υγρού, το οποίο βασίζεται στην εκχύλιση με αντιρροή σε συνδυασμό με την τεχνική FAAS για την προσυγκέντρωση και τον προσδιορισμό τοξικών μετάλλων. Η εκχύλιση βασίζεται στην αντίθετη ροή της υδατικής και της οργανικής φάσης, η οποία πραγματοποιείται σε ένα νέο ειδικά κατασκευασμένο θάλαμος μικροεκχύλισης (Extraction Chamber, EC) αντιρροής. Ο προτεινόμενος αυτός θάλαμος είναι κατάλληλος για χρήση οργανικών διαλυτών είτε ελαφρύτερων είτε βαρύτερων του νερού. 4) Στην τελευταία πειραματική μελέτη αναπτύχθηκε για πρώτη φορά ένα πρωτότυπο, πλήρως αυτοματοποιημένο σύστημα HS-SDME, το οποίο βασίζεται στην πλατφόρμα LIS για τον προσδιορισμό ανόργανου υδραργύρου, μέσω της επιτόπου παραγωγής ψυχρού ατμού υδραργύρου σε συνδυασμό με την τεχνική ETAAS. Στο προτεινόμενο σύστημα πραγματοποιείται ανάμιξη του δείγματος και του αναγωγικού αντιδραστηρίου εντός της σύριγγας, με αποτέλεσμα την απελευθέρωση των πτητικών ατμών υδραργύρο. Στο προτεινόμενο σύστημα, εφαρμόστηκαν για πρώτη φορά συνθήκες ελαττωμένης πίεσης σε LIS σύστημα για την αποτελεσματικότερη απελευθέρωση των ατμών του υδραργύρου.

scholarly journals Optimization of Pulsed Electric Field as Standalone “Green” Extraction Procedure for the Recovery of High Value-Added Compounds from Fresh Olive Leaves

Antioxidants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1554
Author(s):  
Vasileios M. Pappas ◽  
Achillia Lakka ◽  
Dimitrios Palaiogiannis ◽  
Vassilis Athanasiadis ◽  
Eleni Bozinou ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Pulse Duration ◽  
Value Added ◽  
Pulsed Electric Field ◽  
Fine Tuning ◽  
Olive Leaves ◽  
Extraction Technology ◽  
Extraction Chamber

Olive leaves (OLL) are reported as a source of valuable antioxidants and as an agricultural by-product/waste. Thus, a twofold objective with multi-level cost and environmental benefits arises for a “green” standalone extraction technology. This study evaluates the OLL waste valorization through maximizing OLL extracts polyphenol concentration utilizing an emerging “green” non-thermal technology, Pulsed Electric Field (PEF). It also provides further insight into the PEF assistance span for static solid-liquid extraction of OLL by choosing and fine-tuning important PEF parameters such as the extraction chamber geometry, electric field strength, pulse duration, pulse period (and frequency), and extraction duration. The produced extracts were evaluated via comparison amongst them and against extracts obtained without the application of PEF. The Folin-Ciocalteu method, high-performance liquid chromatography, and differential scanning calorimetry were used to determine the extraction efficiency. The optimal PEF contribution on the total polyphenols extractability (38% increase with a 117% increase for specific metabolites) was presented for rectangular extraction chamber, 25% v/v ethanol:water solvent, pulse duration (tpulse) 2 μs, electric field strength (E) 0.85 kV cm−1, 100 μs period (Τ), and 15 min extraction duration (textraction), ascertaining a significant dependence of PEF assisting extraction performance to the parameters chosen.

scholarly journals A new method for Espresso Coffee brewing: Caffè Firenze

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Alessandro Parenti ◽  
Lorenzo Guerrini ◽  
Piernicola Masella ◽  
Riccardo Dainelli ◽  
Paolo Spugnoli
Keyword(s):  
Visual Analysis ◽  
Water Pressure ◽  
Extraction Methods ◽  
Physical Parameters ◽  
Factors Affecting ◽  
New Device ◽  
Extraction Chamber ◽  
Gas Source ◽  
Espresso Coffee ◽  
Pressure Water

Espresso coffee is the most popular choice for Italian coffee consumers. It has been estimated that every day, in the world, over of 50 million of Espresso cups are taken. As a consequence of this success, a large number of devices to make Espresso have been developed. In this scenario, a new device has been recently developed and patented (Eu. Patent 06 023 798.9; US 2010/0034942 A1). This brew method, named “Caffè Firenze”, uses a sealed extraction chamber, where water and gas provides pressure higher than the other extraction methods. Three main parts compose the apparatus: the gas source, the extraction chamber and the heat exchanger. The gas source provides the pressured gas required to raise the pressure of the system. The extraction chamber is made with chrome-brass and accessorized with two heating glow plugs. Many are the factors affecting Espresso quality: it is known that, coffee type, roasting conditions and degree, grinding and storage strongly affect the obtained brew. Also, several studies have been carried out on the effect of the setting parameters on quality, for example water pressure, water temperature, and brew time. Among the characteristics that determine Espresso quality, the main attribute for the visual analysis is, without doubts, the foam, also called “crema”. Indeed, height, aspect, and persistency of foam are features much appreciates by consumers. Two distinguish Espresso foam parameters are the persistency and foam index. Equipping a commercial bar machine with the new designed extraction chamber makes feasible the comparison between the traditional way to brew Espresso and the new device. The comparison was made holding the previous mentioned conditions, and differences were evaluated in terms of physical parameters and aromatic profiles. Caffè Firenze shows pronounced differences compared with traditional Espresso in term of foam-related parameters. Also, the new extraction device produces coffees with higher values of body-related parameters, such density and viscosity. The two kinds of Espressos are perceived different at visual analysis and taste by a panel test.

A Numerical Study of Wave Energy Converter in the Form of an Oscillating Water Column Based on a Mixed Eulerian-Lagrangian Formulation

2010 ◽  
Author(s):  
Chunrong Liu ◽  
Zhenhua Huang ◽  
Adrian Law Wing Keung ◽  
Nan Geng
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Numerical Study ◽  
Integral Equation Method ◽  
Boundary Integral ◽  
Lagrangian Formulation ◽  
Oscillating Water Column ◽  
Extraction Chamber ◽  
Air Chamber ◽  
Air Turbine

A desingularized boundary integral equation method (DBIEM) is employed to study the wave energy extraction by an oscillating water column (OWC) device. The method is based on a mixed-Eulerian-Lagrangian formulation. We examine the effects of the relative draught on the efficiency of 2D OWC energy converters. The oscillating air pressure inside the OWC chamber is modeled by assuming that the air is incompressible and the air-turbine mass-flow rate is proportional to the pressure difference (a linear turbine). For shallow draughts the numerical results agree well with available analytical results. The wave-excited seiching inside the extraction chamber is discussed and the variation of extraction efficiency with dimensionless air-chamber width for different immersion depths is reported.

scholarly journals Performance comparison of microwave cavities used for extraction operations

2020 ◽  
Author(s):  
Giacinto d’Amore ◽  
Giuseppe D’Auria ◽  
Aldo Romano ◽  
Francesco Marra
Keyword(s):  
Energy Content ◽  
Vapour Phase ◽  
Performance Comparison ◽  
Calorimetric Analysis ◽  
Microwave Cavities ◽  
Extraction Chamber ◽  
Electromagnetic Power ◽  
Additional Process ◽  
Extraction Processes ◽  
The Mean

AbstractIn the agri-food industry world, billions of tons of waste are produced every year. This represents both a direct loss (due to the failure to exploit their potential value, and their nutritional and energy content) and indirect loss, due to their necessary treatment and/or disposal. Some substances contained in the wastes, of potential high value, can be recovered by means of extraction. Conventional extraction processes involve the use of solvents, which end up requiring an additional process of separation from the solute identified as the desired product. In recent years, extraction techniques have been proposed without the use of solvents. This work compares the performance of two microwave cavities used for extraction operations, both working at 2.45 GHz.A calorimetric analysis performed by following the heating rate and temperature evolution in rack of 25 beakers filled with 25 mL of water, coupled with the solution of the heat transfer balance in the system, allowed to build the spatial distribution of the electromagnetic power dissipated as heat in each of the beakers. Fluid-dynamics aspects related to the recovery of the vapour phase produced during the extraction were also analyzed, with particular emphasis on the mean residence time of the vapour fraction in the extraction chamber as a function of its configuration.

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