Flow, thermal and structural application of Ni-foam as volumetric solar receiver

Open-cell nickel foams with 92% porosity and uniform pore size and distribution were used in this study. The main objective of this work was to evaluate the behaviour of Ni-foam, when treated as volumetric receivers under concentrated solar radiation while improving their oxidation resistance, in order to make them attractive for such applications. The experimental investigation showed that their efficiency was depending on both materials parameters and flow conditions, the latter affecting the pressure drop and the heat transfer behaviour. The microstructural characterisation of oxide surface morphologies formed on the open-cell Ni foams exposed to concentrated solar radiation is investigated by the use of SEM and EDXS. SEM observations revealed a rapid homogeneous oxidation in the Ni-foam with three different surface oxide structures formed in relation with the process temperature. A novel slurry-based process for aluminising nickel foams while retaining their geometrical properties is applied in order to develop an aluminide-nickel intermetallic coating on a Ni foam thus enhancing the oxidation resistance. Scanning electron microscopy and X-ray diffraction were applied to assess the effectiveness of the aluminising process and determine the optimum parameters of the procedure (slurry composition, holding temperature and time).The authors would like to thank the PROcedes Materiaux et Energie Solaire (PROMES)–Centre National de la Recherche Scientifique (CNRS) for their support in the experimental procedure in the frame of the European Project SOLFACE.Publicad

Visualization of positive and negative sense viral RNA for probing the mechanism of direct-acting antivirals against hepatitis C virus

RNA viruses are highly successful pathogens and are the causative agents for many important diseases. To fully understand the replication of these viruses it is necessary to address the roles of both positive-strand RNA ((+)RNA) and negative-strand RNA ((-)RNA), and their interplay with viral and host proteins. Here we used branched DNA (bDNA) fluorescence in situ hybridization (FISH) to stain both the abundant (+)RNA and the far less abundant (-)RNA in both hepatitis C virus (HCV)- and Zika virus-infected cells, and combined these analyses with visualization of viral proteins through confocal imaging. We were able to phenotypically examine HCV-infected cells in the presence of uninfected cells and revealed the effect of direct-acting antivirals on HCV (+)RNA, (-)RNA, and protein, within hours of commencing treatment. Herein, we demonstrate that bDNA FISH is a powerful tool for the study of RNA viruses that can provide insights into drug efficacy and mechanism of action

REMOVAL OF LEAD (Pb ) AND ZINC (Zn ) FROM AQUEOUS SOLUTIONS BY ADSORPTION ON VERMICULITE FROM ASKOS AREA IN MACEDONIA (NORTHERN GREECE).

The lead and zinc removal from their aqueous solutions by vermiculite samples from Askos area, Northern Greece, was studied using a batch type method. Askos vermiculite is mainly consisted of mixed-layer phyllosilicates. A standard vermiculite sample from Kent, Connecticut was also used for comparison reasons. The concentration of the solutions used varied between 100 and 2000mg/L The maximum uptake capacity of the Askos vermiculite for lead and zinc was found to reach 95% and 96% from solutions containing 100mg/L, respectively. Much lower uptake capacities: 37% for lead and 76% for zinc were found for the Kent vermiculite. The experimental results showed that the Askos vermiculite exhibited an acceptable high capacity for removing metal ions from aqueous solutions. Thus, this untreated and low-cost mineral can find use in purifying heavy metal wastewaters. The uptake distribution coefficient (Kd) showed that the relative lead and zinc removal is higher for initial concentrations below 1000mg/L Batch adsorption experiments conducted at room temperature (22±1°C) showed that the adsorption patterns followed the Freundlich isotherm model. The heavy metal (Pb2+, Zn2+) removal is a rather complicated phenomenon related both to the aqueous chemistry of the elements and the interaction of their cationic species with the used materials. The removal procedure can be attributed to different processes such as ion exchange, adsorption, and precipitation

Spectroscopic and thermal study of bentonites from Milos Island, Greece

Ο μπεντονίτης, με πληθώρα εφαρμογών και χρήσεων, αποτελεί μια από τις σημαντικότερες βιομηχανικές πρώτες ύλες. Στις περισσότερες περιπτώσεις, ο μπεντονίτης αποτελείται κυρίως από μοντμοριλλονίτη, ένα 2:1 αργιλικό ορυκτό με δομή που αποτελείται από ένα οκτάεδρο αργιλίου που τοποθετείται μεταξύ δύο τετραέδρων πυριτίου. Τρία σύνθετα δείγματα μπεντονίτη (ΒΝ1, ΒΝ2, ΒΝ3) με διαφορές τόσο στην ορυκτολογική όσο και στην χημική σύσταση από το νησί της Μήλου, μελετήθηκαν με την μέθοδο της περιθλασιμετρίας ακτίνων-Χ (XRD), με την μέθοδο της φασματοσκοπίας ατομικής απορρόφησης (A.A.S.), με διαφορική θερμική (DTA) και θερμοσταθμική ανάλυση (TG), με φασματοσκοπία υπέρυθρης ακτινοβολίας με μετασχηματισμούς Fourier (FTIR) και με μετρήσεις της ειδικής επιφάνειας (BET). Ορυκτολογικά τα δείγματα χαρακτηρίζονται από υψηλό ποσοστό σμεκτίτη (>85%) και μικρά ποσοστά άλλων αργιλικών ορυκτών (ιλλίτης και καολινίτης). Προσδιορίστηκαν, επίσης, χαμηλά ποσοστά μη αργιλικών ορυκτών όπως χαλαζίας, ασβεστίτης και σιδηροπυρίτης. Το υπέρυθρο φάσμα των δειγμάτων επιβεβαίωσε την παρουσία του διοκταεδρικού σμεκτίτη ως κύριου συστατικού και του χαλαζία ως κύριας πρόσμιξης σε όλα τα δείγματα. Η δόνηση στα 3698cm-1 στο δείγμα ΒΝ3 αποδόθηκε στην παρουσία καολινίτη. Οι καμπύλες DTA/TG όλων των δειγμάτων μετρήθηκαν στο θερμοκρασιακό εύρος 75-100000oC. Οι συνολικές απώλειες βάρους προσδιορίστηκαν σε 16.25, 12.32 και 13.35% για τα δείγματα ΒΝ1, ΒΝ2 και ΒΝ3, αντίστοιχα.Bentonitic clays, currently in use in over hundred areas, are among the most important industrial raw materials. In most of the cases, bentonites predominantly consist of montmorillonite which is a 2:1 layer clay mineral formed by one alumina octahedral sheet placed between two silica tetrahedral sheets. Three bentonite composite samples (BN1, BN2, BN3) with some differences in mineralogical and chemical composition from Milos island (“Miloan”), Greece were investigated by X-ray diffraction (XRD), atomic absorption spectrometry (AAS), differential thermal analysis (DTA), thermogravimetric analysis (TG), Fourier transform infrared (FTIR) and surface area (BET) measurements techniques. Mineralogically, bentonite samples were characterized by high concentrations of smectite (>85%) and minor amounts of other clay minerals (illite and kaolinite). Nonclay minerals such as quartz, calcite and pyrite were also identified. The infrared spectrum of the bentonites also revealed the presence of dioctahedral smectite as the major component and quartz as the main impurity in all the samples. The stretching vibration at 3698cm-1 in the sample BN3 could be ascribed to kaolinite. DTA-TG curves of all samples were measured in the temperature range 75-1000oC. The total weight losses for the bentonite samples BN1, BN2 and BN3 were determined as 16.25, 12.32 and 13.35% respectively

Spectroscopic and thermal study of bentonites from Milos Island, Greece

Ο μπεντονίτης, με πληθώρα εφαρμογών και χρήσεων, αποτελεί μια από τις σημαντικότερες βιομηχανικές πρώτες ύλες. Στις περισσότερες περιπτώσεις, ο μπεντονίτης αποτελείται κυρίως από μοντμοριλλονίτη, ένα 2:1 αργιλικό ορυκτό με δομή που αποτελείται από ένα οκτάεδρο αργιλίου που τοποθετείται μεταξύ δύο τετραέδρων πυριτίου. Τρία σύνθετα δείγματα μπεντονίτη (ΒΝ1, ΒΝ2, ΒΝ3) με διαφορές τόσο στην ορυκτολογική όσο και στην χημική σύσταση από το νησί της Μήλου, μελετήθηκαν με την μέθοδο της περιθλασιμετρίας ακτίνων-Χ (XRD), με την μέθοδο της φασματοσκοπίας ατομικής απορρόφησης (A.A.S.), με διαφορική θερμική (DTA) και θερμοσταθμική ανάλυση (TG), με φασματοσκοπία υπέρυθρης ακτινοβολίας με μετασχηματισμούς Fourier (FTIR) και με μετρήσεις της ειδικής επιφάνειας (BET). Ορυκτολογικά τα δείγματα χαρακτηρίζονται από υψηλό ποσοστό σμεκτίτη (>85%) και μικρά ποσοστά άλλων αργιλικών ορυκτών (ιλλίτης και καολινίτης). Προσδιορίστηκαν, επίσης, χαμηλά ποσοστά μη αργιλικών ορυκτών όπως χαλαζίας, ασβεστίτης και σιδηροπυρίτης. Το υπέρυθρο φάσμα των δειγμάτων επιβεβαίωσε την παρουσία του διοκταεδρικού σμεκτίτη ως κύριου συστατικού και του χαλαζία ως κύριας πρόσμιξης σε όλα τα δείγματα. Η δόνηση στα 3698cm-1 στο δείγμα ΒΝ3 αποδόθηκε στην παρουσία καολινίτη. Οι καμπύλες DTA/TG όλων των δειγμάτων μετρήθηκαν στο θερμοκρασιακό εύρος 75-100000oC. Οι συνολικές απώλειες βάρους προσδιορίστηκαν σε 16.25, 12.32 και 13.35% για τα δείγματα ΒΝ1, ΒΝ2 και ΒΝ3, αντίστοιχα.Bentonitic clays, currently in use in over hundred areas, are among the most important industrial raw materials. In most of the cases, bentonites predominantly consist of montmorillonite which is a 2:1 layer clay mineral formed by one alumina octahedral sheet placed between two silica tetrahedral sheets. Three bentonite composite samples (BN1, BN2, BN3) with some differences in mineralogical and chemical composition from Milos island (“Miloan”), Greece were investigated by X-ray diffraction (XRD), atomic absorption spectrometry (AAS), differential thermal analysis (DTA), thermogravimetric analysis (TG), Fourier transform infrared (FTIR) and surface area (BET) measurements techniques. Mineralogically, bentonite samples were characterized by high concentrations of smectite (>85%) and minor amounts of other clay minerals (illite and kaolinite). Nonclay minerals such as quartz, calcite and pyrite were also identified. The infrared spectrum of the bentonites also revealed the presence of dioctahedral smectite as the major component and quartz as the main impurity in all the samples. The stretching vibration at 3698cm-1 in the sample BN3 could be ascribed to kaolinite. DTA-TG curves of all samples were measured in the temperature range 75-1000oC. The total weight losses for the bentonite samples BN1, BN2 and BN3 were determined as 16.25, 12.32 and 13.35% respectively

Path combinatorics and light leaves for quiver Hecke algebras

We recast the classical notion of standard tableaux in an alcove-geometric setting and extend these classical ideas to all reduced paths in our geometry. This broader path-perspective is essential for implementing the higher categorical ideas of Elias--Williamson in the setting of quiver Hecke algebras. Our first main result is the construction of light leaves bases of quiver Hecke algebras. These bases are richer and encode more structural information than their classical counterparts, even in the case of the symmetric groups. Our second main result provides path-theoretic generators for the Bott--Samelson truncation of the quiver Hecke algebra

MUNICIPAL WASTEWATER TREATMENT WITH BENTONITE FROM MILOS ISLAND, GREECE

Bentonite clay minerals belonging to the smectite group have a wide range of chemical and industrial uses. The structure and chemical composition, exchangeable ion type and small crystal size of smectite are responsible for several properties, including a large chemically active surface area and a high cation exchange capacity. A wastewater treatment using bentonite from Milos island, Greece, was investigated. Raw wastewater sample (influent) from the wastewater treatment plant (WTP) of the city of Kilkis, Northern Greece was treated using bentonite in conjunction with chemical coagulants (polyaluminium chloride-PAC and cationic polyelectrolyte), in batch type experiments. Theremoval of suspended solids (SS), chemical oxygen demand (COD), nitrate ion, ammonium ion, phosphate ion, and toxic metals were evaluated. The treatment gave overflowed clear water improved concerning the quality parameters. The bentonite adding prior to flocculation resulted in effective removal of heavy metals such as chromium and copper. Additionally, the bentonite removed nitrogen compounds with relatively high efficiency, while the clay presence highly improved the COD removal. The quality parameters after treatment were improved fulfilling the requirements for disposition as downstream, irrigation, swimming and fish waters