Spelling suggestions: "subject:"water soluble"" "subject:"later soluble""
71 |
New developments in main group and transition metal chemistry of water-soluble phospinesBerning, Douglas E. January 1997 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 240-150). Also available on the Internet.
|
72 |
Free radical polymerization of N-vinylformamide and novel comb structure polyelectrolytes /Gu, Leming January 2001 (has links)
Thesis ( Ph.D) -- McMaster University, 2001. / Includes bibliographical references. Also available via World Wide Web.
|
73 |
Αξιοποίηση της ερυθράς ιλύος στις βιομηχανίες τσιμέντουΒαγγελάτος, Ιωάννης 19 April 2010 (has links)
Στην παρούσα διατριβή εξετάστηκε η δυνατότητα χρήσης της σιδηραλούμινας, του προϊόντος που προέρχεται από την επεξεργασία της ερυθράς ιλύος, ως πρώτη ύλη και ως πρόσθετο στη διεργασία παραγωγής τσιμέντου.
Η ερυθρά ιλύς αποτελεί το παραπροϊόν της επεξεργασίας του βωξίτη για την παραγωγή αλούμινας μέσω της διεργασίας Bayer. Αποτελείται από το τμήμα του βωξίτη που δεν αντιδρά, το τμήμα του βωξίτη που έχει αντιδράσει προς το σχηματισμό άλλων ενώσεων, από συστατικά που εισάγονται στη διεργασία και από τα υδροξείδια του αργιλίου που δεν ανακτώνται.
Η απομάκρυνση του νερού από την ερυθρά ιλύ έχει ως αποτέλεσμα την παραγωγή ενός στερεού υπολείμματος, της σιδηραλούμινας. Αν και υπάρχουν αρκετές διαθέσιμες τεχνολογίες για απομάκρυνση του νερού, η χρήση πρέσας φίλτρων υψηλής πίεσης συγκεντρώνει πολλά προτερήματα. Η μελέτη απομάκρυνσης του νερού πραγματοποιήθηκε σε μια εργαστηριακής κλίμακας πρέσα φίλτρων, όπου και διαπιστώθηκε ότι είναι δυνατή η παραγωγή στερεού υπολείμματος (κέικ) με περιεκτικότητα ~35% σε νερό. Η έρευνα επεκτάθηκε σε πιλοτικής κλίμακας πρέσα φίλτρων όπου εξετάστηκαν περισσότερες παράμετροι, όπως ο τύπος του φίλτρου και το υλικό από το οποίο είναι φτιαγμένο. Τα αποτελέσματα έδειξαν ότι είναι δυνατή η παραγωγή στερεού υπολείμματος με σταθερό ποσοστό υγρασίας μεταξύ 27% και 32% και πυκνότητα περίπου 2g/cm3, οδηγώντας στην εγκατάσταση μιας βιομηχανικής πρέσας φίλτρων υψηλής πίεσης, η οποία λειτουργεί από την αρχή του 2006 με επιτυχία στο «Αλουμίνιο της Ελλάδας».
Η χημική ανάλυση της σιδηραλούμινας καταδεικνύει ότι πρόκειται για ένα υλικό που μπορεί να χρησιμοποιηθεί σαν δευτερεύουσα πρώτη ύλη στην βιομηχανία τσιμέντου ως φορέας σιδήρου. Η μελέτη της καταλληλότητάς
της πραγματοποιήθηκε με το σχεδιασμό μιγμάτων πρώτων υλών για την παραγωγή τσιμέντου τύπου Portland στα οποία η σιδηραλούμινα συμμετείχε σε ποσοστά έως 5%κ.β. Τα αποτελέσματα έδειξαν ότι τα παραγόμενα με σιδηραλούμινα τσιμέντα παρουσιάζουν ίδια ποιοτικά ορυκτολογική σύσταση με το αντίστοιχο αναφοράς ενώ οι φυσικές τους ιδιότητες όπως η απαίτηση σε νερό και ο χρόνος πήξης βρίσκονται στα ίδια επίπεδα. Όσον αφορά στις μηχανικές τους ιδιότητες, οι τιμές που ελήφθησαν κατατάσσουν όλα τα τσιμέντα στην κατηγορία των 42.5N. Ειδικότερα τα τσιμέντα με σιδηραλούμινα κατατάσσονται σε υψηλότερη κατηγορία (52.5N) λόγω των αυξημένων πρώιμων αντοχών (2 ημερών). Τέλος, τα παραγόμενα με σιδηραλούμινα τσιμέντα έδειξαν ότι απελευθερώνουν μεγαλύτερη ποσότητα υδατοδιαλυτού χρωμίου από το τσιμέντο αναφοράς, απόρροια του υψηλότερου αρχικού φορτίου ολικού χρωμίου που περιέχουν.
Οι βιομηχανικές δοκιμές που ακολούθησαν στις βιομηχανίες ΤΙΤΑΝ και ΑΓΕΤ ΗΡΑΚΛΗΣ έδειξαν ότι η προσθήκη σιδηραλούμινας σε επίπεδα 2.7%κ.β οδηγεί σε βελτίωση της εψησιμότητας του μίγματος λόγω της μείωσης του πυριτικού δείκτη. Επίσης η προσθήκη σιδηραλούμινας προς αντικατάσταση του χρησιμοποιούμενου πυρίτη στο μίγμα οδήγησε στη μείωση των ιχνοστοιχείων Mn, Pb, Zn και Cu στο μίγμα ενώ αύξησε το ποσοστό του Cr. Τα αποτελέσματα για το παραγόμενο κλίνκερ έδειξαν ότι η προσθήκη δεν επηρέασε ποιοτικά τις σχηματιζόμενες ορυκτολογικές φάσεις ενώ οι αντοχές που παρουσίασαν τα παραγόμενα τσιμέντα φτάνουν τα 27.7MPa για τις πρώτες 2 ημέρες και τα 51.6MPa μετά από 28 ημέρες. Η επίδραση της προσθήκης στους αέριους ρύπους των εργοστασίων ήταν μηδενική, καθώς οι τιμές αυτών παρέμειναν στα ίδια επίπεδα κατά τη διεργασία παραγωγής.
Προκειμένου να αξιολογηθεί η περιβαλλοντική συμπεριφορά των παραγόμενων με σιδηραλούμινα τσιμέντων, πραγματοποιήθηκαν δοκιμές εκπλυσιμότητας. Για τις δοκιμές χρησιμοποιήθηκαν δύο δείγματα τσιμέντου, ένα χωρίς σιδηραλούμινα (αναφορά) και ένα 2%κ.β σιδηραλούμινα. Οι ανωτέρω δοκιμές πραγματοποιήθηκαν υπό το πρίσμα δύο προτύπων, του NEN 7345-tank test που αναφέρεται σε μονολιθικά υλικά (service life scenario) και του prEN 14429-pH dependence test που αναφέρεται σε κοκκώδη υλικά (“second life” scenario). Σύμφωνα με τη χημική ανάλυση των δύο τσιμέντων, το τσιμέντο με σιδηραλούμινα παρουσιάζει μεγαλύτερο αρχικό φορτίο σε Cr, Ni και V από το αντίστοιχο αναφοράς. Το παραπάνω γεγονός δεν επηρεάζει την απελευθέρωση στην περίπτωση του μονολιθικού υλικού, όπου τόσο για την περίπτωση του Cr όσο και για αυτές των Ni και V παρατηρούνται ίδια επίπεδα απελευθέρωσης τόσο για το δοκίμιο αναφοράς όσο και για το δοκίμιο με σιδηραλούμινα. Στην περίπτωση του κοκκώδους (θραυσμένου) υλικού η απελευθέρωση των ιχνοστοιχείων στο περιβάλλον είναι ανάλογη του αρχικού τους φορτίου και εντείνεται καθώς η ισορροπία μετατοπίζεται προς χαμηλότερα pH.
Οι σύγχρονες τάσεις που αφορούν την εξοικονόμηση ενέργειας και την προστασία του περιβάλλοντος έστρεψαν την έρευνα στη δυνατότητα προσθήκης σιδηραλούμινας ως πρώτη ύλη για την παραγωγή τσιμέντων μπελιτικού τύπου. Η διαφορά των ανωτέρω τσιμέντων με τα τσιμέντα τύπου Portland είναι τα μειωμένα επίπεδα της φάσης του πυριτικού τριασβεστίου (C3S) απόρροια της χαμηλότερης θερμοκρασίας έψησης (~1350οC) γεγονός που τα κατατάσσει στην κατηγορία των φιλικών προς το περιβάλλον τσιμέντων. Τα αποτελέσματα έδειξαν ότι η χρήση σιδηραλούμινας για την παραγωγή μπελιτικών τσιμέντων είναι εφικτή αλλά και ότι τα τσιμέντα αυτού του τύπου έχουν ένα σαφές μειονέκτημα έναντι των Portland, τις χαμηλές πρώιμες αντοχές τους. Το μειονέκτημα αυτό αντιμετωπίστηκε με την εισαγωγή γύψου στο μίγμα των πρώτων υλών που είχε ως επακόλουθο τη δημιουργία της υδραυλικής ένωσης 4CaO.3Al2O3.SO3 κατά τη διαδικασία έψησης.
Τέλος εξετάστηκε η δυνατότητα της σιδηραλούμινας να δράσει ως υπόστρωμα για την ρόφηση του εξασθενούς χρωμίου (Cr(VI)) σε υδατικά διαλύματα προκειμένου να χρησιμοποιηθεί ως πρόσθετο στο τελευταίο στάδιο της παραγωγής τσιμέντου. Η μελέτη πραγματοποιήθηκε λαμβάνοντας υπ’ όψιν παραμέτρους όπως το pH του διαλύματος, ο χρόνος επαφής και η αναλογία υγρού προς στερεό (l:s ratio). Τα αποτελέσματα κατέδειξαν ότι η σιδηραλούμινα εμφανίζει ροφητικές ιδιότητες οι οποίες αυξάνονται εάν προηγηθεί ένα στάδιο χημικής και θερμικής επεξεργασίας αυτής. Αυτό οφείλεται στην αύξηση της ειδικής επιφάνειας της σιδηραλούμινας από τα 10m2 g-1 στα 70m2 g-1 λόγω της αύξησης του μικροπορώδους της. Τα επίπεδα ρόφησης χρωμίου για την επεξεργασμένη σιδηραλούμινα έφτασαν σε ιδανικές συνθήκες στα 0.82mg g-1. Ο μηχανισμός της ρόφησης περιγράφεται από την ισόθερμη Langmuir ενώ περιορίζεται σε μια στενή περιοχή τιμών του pH ανάμεσα στο 5 και στο 6. / In the present thesis the potential utilization of ferroalumina, a by-product that derives from the dewatering of red mud, as a raw material as well as an additive material in the cement production route is examined.
Red mud is the main by-product that derives from the digestion of bauxite ores during Bayer process in order to produce alumina. It comprises from the ore part that has not reacted, the part that has reacted and has formed other than the desired compounds, from supplementary materials that were introduced during the procedure and from aluminium hydroxides that were not recovered.
The removal of red mud’s water content leads to the production of ferroalumina. Although there are many ways of removing the water, the use of a filter press has many advantages. The laboratory study of the water removal from red mud by means of a filter press led to the formation of a cake with ~35%wt of water. Parameters, such as the filter type and the material that it comprises were examined with the further use of a pilot scale filter press. The results indicated that the filter press can produce a cake with constant water amount between 27% and 32%wt and density 2g/cm3. The latter results, led to the installation of an industrial high pressure filter press, which is in operation since the beginning of 2006, in the Aluminium Hellas industry.
Ferroalumina’s chemical analysis indicates that it can be used as a secondary material in the cement industry, mainly as an iron oxide carrier. The study for its suitability was performed by preparing Portland cement raw mixtures introducing ferroalumina up to 5%wt are a raw material. Consequently, the raw mixtures were fired up to 1550oC in order to produce clinker and co-grounded with gypsum in order to produce Portland cement. The results indicate that the produced ferroalumina cements presents similar mineralogical composition with the cements without ferroalumina whilst their physical properties such as the water demand and the setting time are at the same levels. Regarding their mechanical properties, the obtained compressive strength values are ranking all the cements in the 42.5N category. Especially the ferroalumina cements are falling into a higher category and more specifically in the 52.5N category due to their high early day strengths. Finally, the study indicate that the ferroalumina cements presents higher amounts of water soluble chromium than the cement without ferroalumina (reference), most probably due to their higher initial amount of total chromium.
The industrial trials that were performed by the Greek cement industries TITAN and AGET Heracles showed that the addition of ferroalumina up to 2.7%wt improves the burnability of the mixture due to the silica modulus reduction. The substitution of the raw material pyrite from the ferroalumina, led to the reduction of Mn, Pb, Zn and Cu on the raw mixture whilst it increased the Cr percentage. The results for the produced clinker indicate that the ferroalumina addition did not affect the formatted mineralogical phases. The compressive strength values of the obtained cements, was 27.7MPa after the first 2 days and 51.6MPa after 28 days of curing. The flue gas emissions were at the same levels during the cement production indicating that the ferroalumina addition does not affect that part of production either.
In order to evaluate the environmental behaviour of the ferroalumina cements, two types of leaching tests, which refer to different field scenarios, were employed. The NEN 7345-tank test which refers to monolithic materials (“service life” scenario) and the prEN 14429-pH dependence test, which concerns granular materials (“second life” scenario). Two different cement samples were used for the above mentioned tests. The first one was produced without ferroalumina (reference sample) whilst the second one was produced with a 2%wt ferroalumina addition. The chemical analysis of the cement with ferroalumina showed that it presents greater content of Cr, Ni and V than the reference cement. The latter does not affect leaching in the service life scenario. More specifically in the case of Cr the reference cement presents the same leaching amount with the ferroalumina cement whilst in the case of Ni and V no leaching is observed for any of the two cement samples. During the “second life” scenario the leaching is greater in the case of the ferroalumina cement. The latter is related to the greater initial content of the above mentioned cement in Cr, Ni and V. The leaching behaviour is for both cements pH sensitive as higher leaching values for Cr and Ni are observed while the pH shifts to lower values.
The new trends concerning the sustainable development through energy conversion and environmental protection have led the current study in the utilization of ferroalumina in the field of belite cements. The main difference of the above mentioned cements from the Portland cements is the low content in calcium silicate (C3S) mainly due to the lower firing temperature (~1350οC). The latter ranks the above mentioned cements in the environmental friendly cements category (green cements). The obtained results indicate that the use of ferroalumina as a raw material for the production of belite cements is possible as well as that the produced cements have a certain drawback when compared with the OPC. The lack of C3S leads to low early day strength. This drawback was confronted with the introduction of gypsum in the raw mixture which led to the formation of the hydraulic compound 4CaO.3Al2O3.SO3 (Klein’s compound) during the firing procedure.
The last chapter deals with the possibility of utilize ferroalumina as a substrate for the absorption of hexavalent chromium in order to use it as an additive material in the last stage of cement production. The study examined parameters such as the pH of the solution, the contact time and the liquid to solid ratio (l:s ratio). The results indicate that the ferroalumina is able to absorb chromium and that this ability increases if a stage of chemical and thermal treatment is employed before. The treatment enhances ferroalumina’s absorption ability due to an increase of specific surface from 10m2 g-1 to 70m2 g-1. The absorbance mechanism is described with the Langmuir model and the best results are obtained for pH 5 and contact time 1h. The amount of chromium that is absorbed from each grammar of ferroalumina in the above mentioned conditions is 0.82mg.
|
74 |
Characterization of Carbonaceous Aerosol over the North Atlantic OceanJanuary 2011 (has links)
abstract: Atmospheric particulate matter has a substantial impact on global climate due to its ability to absorb/scatter solar radiation and act as cloud condensation nuclei (CCN). Yet, little is known about marine aerosol, in particular, the carbonaceous fraction. In the present work, particulate matter was collected, using High Volume (HiVol) samplers, onto quartz fiber substrates during a series of research cruises on the Atlantic Ocean. Samples were collected on board the R/V Endeavor on West–East (March–April, 2006) and East–West (June–July, 2006) transects in the North Atlantic, as well as on the R/V Polarstern during a North–South (October–November, 2005) transect along the western coast of Europe and Africa. The aerosol total carbon (TC) concentrations for the West–East (Narragansett, RI, USA to Nice, France) and East–West (Heraklion, Crete, Greece to Narragansett, RI, USA) transects were generally low over the open ocean (0.36±0.14 μg C/m3) and increased as the ship approached coastal areas (2.18±1.37 μg C/m3), due to increased terrestrial/anthropogenic aerosol inputs. The TC for the North–South transect samples decreased in the southern hemisphere with the exception of samples collected near the 15th parallel where calculations indicate the air mass back trajectories originated from the continent. Seasonal variation in organic carbon (OC) was seen in the northern hemisphere open ocean samples with average values of 0.45 μg/m3 and 0.26 μg/m3 for spring and summer, respectively. These low summer time values are consistent with SeaWiFS satellite images that show decreasing chlorophyll a concentration (a proxy for phytoplankton biomass) in the summer. There is also a statistically significant (p<0.05) decline in surface water fluorescence in the summer. Moreover, examination of water–soluble organic carbon (WSOC) shows that the summer aerosol samples appear to have a higher fraction of the lower molecular weight material, indicating that the samples may be more oxidized (aged). The seasonal variation in aerosol content seen during the two 2006 cruises is evidence that a primary biological marine source is a significant contributor to the carbonaceous particulate in the marine atmosphere and is consistent with previous studies of clean marine air masses. / Dissertation/Thesis / M.S. Chemistry 2011
|
75 |
Synthesis, coordination chemistry, and reactivity of functionalized phosphines: Toward water-soluble macrocyclic phosphine complexesSwor, Charles D. (Charles David), 1982- 03 1900 (has links)
xx, 290 p. : ill. (some col.) / Macrocyclic phosphine compounds have long been sought as ligands for transition metal complexes because of their strong binding properties. Despite considerable effort in this field, no general methods for synthesizing phosphine macrocycles or their complexes have been developed. This dissertation describes attempts to synthesize an iron complex with a water-soluble macrocyclic tetraphosphine ligand for use in separating nitrogen from natural gas. Chapter I reviews previous syntheses of macrocyclic phosphine ligands and their complexes, focusing on ligand synthesis, coordination chemistry, and demetallation of the complexes.
Chapter II reports on the synthesis of water-soluble secondary bidentate phosphine ligands, their coordination chemistry with iron(II), and attempts to use these complexes as templates for forming a macrocyclic iron-phosphine complex by reactions with carbon electrophiles.
Over the course of treating these iron complexes with various carbon electrophiles, an interesting reaction between bromomaleic anhydride and proton sponge was discovered. Chapter III explores the product, 4-maleicanhydrido-1,8-bis-(dimethylamino)naphthalene (MAPS). Due to its conjugated donor-acceptor network, which is disrupted upon protonation, MAPS acts as a colorimetric version of a proton sponge. The attachment of MAPS to amine-functionalized solid supports, forming solid-supported proton sponge reagents, is also described.
Chapter IV discusses the synthesis of an iron(II) complex of the water-soluble phosphine 1,2-bis(di(hydroxymethyl)phosphino)ethane (DHMPE). Although unbound hydroxymethylphosphines commonly react with NH-functional amines via the phosphorus Mannich reaction, this and other complexes of DHMPE do not undergo this reaction. Further investigation with hydroxymethylphosphine-boranes suggests that the currently-accepted mechanism of the phosphorus Mannich reaction is incorrect, and an alternate mechanism is proposed.
Chapter V discusses the synthesis and functionalization of copper(I) complexes of water-soluble phosphines. Unlike the complexes described in Chapter I, these complexes readily react with α,ω-dihalides or di(acyl chloride)s, forming complexes whose mass spectra correspond to those with macrocyclic phosphine ligands. Unlike most macrocyclic tetraphosphine complexes, these complexes can be demetallated by treatment with sulfide. Finally, a new synthesis of water-soluble macrocycles, based on lessons learned during the course of these investigations, is proposed.
This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Dr. Michael M. Haley, Chairperson;
Dr. David R. Tyler, Advisor;
Dr. Darren W. Johnson, Member;
Dr. Shih-Yuan Liu, Member;
Dr. Mark H. Reed, Outside Member
|
76 |
Desenvolvimento, otimizaÃÃo e aceitabilidade de bebida de cafà com extrato hidrossolÃvel da amÃndoa de castanha de caju / Development and optimization of acceptability drink coffee with almond hydrosoluble extract chestnut cashewAna Caroline Pinheiro Xerez 23 August 2012 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O cafà à uma bebida bastante apreciada e consumida em todo o mundo, destacando-se tambÃm por sua relevÃncia econÃmica que gera renda e empregabilidade. No Brasil, o cultivo e o processamento de cafà sÃo realizados predominantemente na regiÃo Sudeste. Existem muitas Ãreas produtivas no estado do Cearà que estÃo ociosas devido à falta de estÃmulo dos produtores e incentivo do governo. Apesar disso, ainda hà alguns produtores no MaciÃo de BaturitÃ, CearÃ, Brasil, que mantÃm sua produÃÃo em cooperativismo. Diante disso, esta pesquisa objetivou elaborar e otimizar uma bebida de cafà utilizando grÃos de cafà 100% arÃbica, produzidos no MaciÃo de BaturitÃ, adicionada de um extrato hidrossolÃvel da amÃndoa de castanha de caju (EHACC), de forma a diversificar o mercado de bebidas e agregar valor Ãs matÃrias-primas produzidas no CearÃ. Inicialmente, realizaram-se anÃlise de perfil do consumidor e os testes sensoriais com a bebida de cafà elaborada com grÃos produzidos no CearÃ, a fim de selecionar a matÃria-prima deste estudo. A partir de um planejamento experimental, desenvolveram-se 12 formulaÃÃes de bebida de cafà adicionada de EHACC. No estudo de otimizaÃÃo da bebida considerou-se os fatores quantidade de aÃÃcar (g) e proporÃÃo de cafà (%) atravÃs do desenvolvimento de um delineamento experimental composto central que proporcionou a aplicaÃÃo da metodologia de superfÃcie de resposta (MSR). Esta metodologia foi aplicada Ãs variÃveis fÃsico-quÃmicas cor, pH, ÂBrix e viscosidade e Ãs variÃveis sensoriais impressÃo global, aroma, cor, sabor, amargor e corpo. Para todas as variÃveis foi realizada anÃlise descritiva por meio de tabela de frequÃncia e anÃlise grÃfica. De acordo com os dados do perfil do consumidor, o cafà coado e adicionado de leite foi preferido em relaÃÃo Ãs outras bebidas de cafà e mais de 50% dos consumidores responderam que comprariam uma bebida de cafà pronta para o consumo. A bebida produzida com grÃos de cafà do MaciÃo de Baturità foi classificada como dura atravÃs da âprova de xÃcaraâ. Os limites de restriÃÃo de cafà e aÃÃcar estabelecidos no planejamento definiram os nÃveis que levaram aos pontos Ãtimos das variÃveis fÃsico-quÃmicas cor (coordenadas L* e b*) e pH e das variÃveis sensoriais impressÃo global, aroma e cor da bebida de cafà adicionada de EHACC. Todas as variÃveis sensoriais avaliadas apresentaram boa aceitaÃÃo nas 12 formulaÃÃes testadas. / Coffee is a drink very much appreciated and consumed worldwide, especially also for its economic relevance that generates income and employability. In Brazil, the cultivation and processing of coffee are made predominantly in the Southeast. There are many productive areas in the state of Cearà who are idle due to lack of stimulation of producers and government incentive. Nevertheless, there are still some producers in the Massif BaturitÃ, CearÃ, Brazil to maintain its production cooperatives. Thus, this study aimed to develop and optimize a coffee beverage using coffee beans 100% Arabica, produced in Baturità Massif, added a water soluble extract of almond cashew (EHACC), in order to diversify the beverage market and add value to raw materials produced in CearÃ. Initially, there were consumer profile analysis and sensory tests with a coffee drink made with grain produced in CearÃ, in order to select the raw material of this study. From an experimental design, developed 12 formulations coffee drink with added EHACC. In the optimization study the beverage was considered factors quantity of sugar (g), and proportion of coffee (%) by developing an experimental compound central provided the application of Response Surface Methodology (RSM). This methodology was applied to the physico-chemical color, pH, ÂBrix and viscosity and sensory variables overall impression, aroma, color, flavor, bitterness and body. For all variables were analyzed descriptively by frequency table and graphical analysis. According to the data of the consumer profile, the brewed coffee and milk added was preferred over other coffee beverages and more than 50% of consumers who responded buy a coffee beverage ready for consumption. A drink made with coffee beans of the Massif Baturità was classified as hard through the "cup test". The constraint limits established coffee and sugar defined in planning levels that led to the optimal points of the physico-chemical color (L *, b *) variables, pH and sensory overall impression, color and aroma of the coffee beverage of added EHACC. All variables evaluated showed good sensory acceptance in the 12 formulations tested.
|
77 |
Determinação de íons solúveis em água no material particulado MP10 coletado na Cidade Universitária - São Paulo, 2003 / Water Soluble Ions in the Particulate Matter PM10 collected at Cidade Universitária, São Paulo city, 2003Simone Garcia de Avila 25 February 2011 (has links)
As partículas atmosféricas com diâmetro aerodinâmico menor que 10 µm são classificadas por MP10. Essas partículas podem ser subdivididas em partículas grossas (entre 2,5 e 10 µm) e finas (< 2,5 µm), sendo que as últimas apresentam poder de penetração maior no organismo, podendo atingir os alvéolos pulmonares. O objetivo deste trabalho foi estudar espécies solúveis em água no material particulado MP10, coletado na Cidade Universitária (São Paulo-SP) durante o ano de 2003, como também, investigar a variação sazonal destas espécies na atmosfera de São Paulo, caracterizando as principais fontes de emissões existentes no sítio de estudo, tais como possíveis formações de espécies secundárias e influências de transporte de massas de ar. As amostras foram coletadas no Instituto de Astronomia, Geofísica e Ciências Atmosféricas da USP, utilizando filtros de fibra de quartzo e um amostrador de grande volume. A amostragem ocorreu a cada quinze dias, entre os meses de abril/2003 e maio/2004 (n=28), sendo realizadas também duas amostragens durante dias consecutivos, uma ocorrendo em março/2003 (n=5) e outra em julho/2003 (n=10). Esses dois períodos correspondem a estudos de casos, no qual o primeiro é caracterizado pela ocorrência de precipitação nos dias amostrados, enquanto, o segundo representa dias de ausência de precipitação, característicos do inverno na região de estudo. O tempo de amostragem foi de 24 horas. A extração da fração solúveis em água foi feita por via aquosa e a quantificação por cromatografia de íons. O inverno/2003 representou a estação de maior concentração média de MP10 e também das espécies estudadas, entretanto, considerando o intervalo de concentração obtido em cada estação, no outono/2003 foram encontrados valores de MP10 tão elevados quanto no inverno/2003. Nenhuma amostra apresentou concentração de material particulado acima do limite recomendado pela legislação brasileira (150 µg m-3), porém, considerando o limite de MP10 recomendado pela Organização Mundial de Saúde (50 µg m-3), apenas a primavera/2003 e o verão 2003/2004 não apresentaram amostras acima deste limite. O sulfato representou a espécie mais abundante da fração solúvel em água do MP10, não apresentando grandes variações ao longo das estações do ano. A razão entre os ácidos fórmico e acético mostrou que as reações fotoquímicas contribuem mais intensamente para a presença destas espécies na atmosfera do sítio estudado. O estudo das trajetórias de massas de ar e também as correlações entre as espécies mostraram que o sítio de estudo recebe influência de aerossóis marinhos e também de locais provenientes de queima de biomassa. / PM10 is classified by the atmospheric particulate matter that present the diameter smaller than 10 µm. These particles may be divided in the coarse fraction (diameter between 2,5 and 10 µm) and fine fraction (<2,5 µm). The fine fraction presents high power penetration in the human organism. The objective of this study was to determinate the water-soluble ions in the PM10 collected in the Cidade Universitária (São Paulo, SP) during 2003 year and to investigate the seasonal variation of these species, characterizing the principal emissions sources in the studied site, secondary reaction and air mass transport. Samples were collected in the Instituto de Astronomia, Geofísica e Ciências Atmosféricas of USP, using the high volume sample and fiber quartz filter. The sampling occurred every 15 days, between April/2003 and May/2004 (n=28). It was done two sampling in consecutive days, during March/2003 (n=5) and July (n=10). The first period was characterizing by occurrence of precipitation during the sample days and the second period was characterizing by absence of precipitation. The sample time was 24 hours. The extraction of the water soluble ions was done using water and the quantification by ions chromatography. The winter/2003 presented the highest average concentration of PM10 and of the studied species. However, considering the range of the concentration, the autumn/2003 presented PM10 concentration as high as winter/2003. It was not noticed concentrations of PM10 above that established by Brazilian laws (150 µg m-3), but considering the limit of PM10 established by World Health Organization (50 µg m-3), only spring/2003 and summer 2003/2004 did not present concentration highest than this limit. Sulfate was the more abundant studied species. The concentration of that ion did not present variation each season of the year. The ratio between formic acid and acetic acid showed that the photochemical reaction is the principal responsible for the presence of these acids in the atmosphere of studied site. The study of back mass trajectories and the correlation between same species showed that the São Paulo receive influence of marine aerosol by air mass transported and aerosols by region of the biomass burning, too.
|
78 |
Construction de nouveaux Bodipys solubles pour la concentration d'énergie et les cellules photovoltaïques / Construction of new soluble Bodipys for energy concentration and organic solar cellsBura, Thomas 03 July 2013 (has links)
Les travaux réalisés durant ces années de doctorat ont été axés sur la conception de fluorophores pour diverses applications en fluorescence ou dispositifs de conversion d’énergie. Ainsi, plusieurs composés de la famille des Bodipys et triazatruxène ont été synthétisés, caractérisés et étudiés. En fonction des modifications structurales apportées à ces molécules, il est possible d’obtenir un panel de composés possédant une gamme d’absorption et d’émission pouvant s’étendre de 500 à 800 nm. La modulation de ses propriétés optiques a un intérêt dans un grand nombre d’applications. Ainsi, divers Bodipys ont été synthétisés en vue d’une éventuelle application pour le marquage biologique ou bien servant de support à l’étude du transfert d’énergie intramoléculaire. Le fort pouvoir absorbant de ces composés a été mis à contribution pour la réalisation de cellules solaires organiques originales et performantes. / The work undertaken during this PhD was focused on the design of fluorophores for several applications in fluorescence or energy conversion device. Several compounds from the Bodipy and Triazatruxene families were synthesized, characterized and studied. By structural modifications brought to these molecules, it was possible to obtain a panel of compounds those posses a range of absorption and emission properties which extend from 500 to 800 nm. The modulation of these optical properties has an interest in a large number of applications and field of research. Several Bodipys were synthesized for potential application in biological labeling and specific energy transfer processes. The strong absorption power and dedicated redox properties of these compounds was exploited for the preparation of solar
|
79 |
Development of a degreasing and anti-fogging formulation for wet wipe application for automotive glass surfacesBosch, Tanya January 2012 (has links)
It was the objective of this project to provide a glass cleaner formulation for a wet wipe application with cleaning and anti-fogging properties. This glass cleaner formulation was developed for automotive glass i.e. interior of windscreens. This formulation relates to a glass cleaner with a composition comprising of: (a) a blend of amphoteric surfactants; (b) a solvent system with a combination of glycol ethers; and (c) an aqueous solvent system. This glass formulation must provide good cleaning properties while also providing good wetting and sheeting properties to assist with anti-fogging properties. The objectives were obtained using 2 specific approaches: The first was by using a blend of 2 amphoteric surfactants in an alkaline medium, allowing the glass surface to become more hydrophilic which will also assist with reduction of surface tension on the glass surface. The second was by using the glycol ethers that have good coupling properties and surface tension reducing properties. The formulation was evaluated using commercial standard test methods as per the industry. A predictive model was successfully obtained for each of the five criteria that were evaluated using the 25 formulations derived from the statistical design. There were variables and variable interactions that were antagonistic for some of the criteria which were found to be synergistic for others. To achieve satisfactory cleaning, the fogging rating had to be compromised.
|
80 |
Degradation Of Water Soluble PolymersVijayalakshmi, S P 12 1900 (has links) (PDF)
No description available.
|
Page generated in 0.3525 seconds