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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Thermal behavior of spiral bevel gears

Handschuh, Robert Frederick January 1993 (has links)
No description available.
2

Estudo do polimorfismo dos edulcorantes artificiais sacarina, sacarina sódica, ciclamato de sódio e acesulfame-K / Study of polymorphism in artificial sweeteners saccharin, sodium saccharin, sodium cyclamte and acesulfame-K

Medina, Deyber Arley Vargas 27 August 2013 (has links)
O polimorfismo nos edulcorantes artificiais sacarina, sacarina sódica, ciclamato de sódio e acesulfame-K foi estudado a partir da obtenção de cristais mediante evaporação lenta de solvente, em diferentes temperaturas e sistemas solventes. As formas sólidas obtidas foram caracterizadas mediante o emprego de técnicas temoanalíticas e de difração de raios X. Estabeleceu-se a existência de três hábitos cristalinos isomórficos e uma forma semicristalina de sacarina, três formas pseudopolimórficas de sacarina sódica, duas formas pseudopolimórficas de ciclamato de sódio e duas formas polimórficas e uma amorfa de acesulfame-K. / The polymorphism in the artificial sweeteners saccharin, sodium saccharin, sodium cyclamate and acesulfame-K was studied from crystals obtained by slow evaporation of solvent at different temperatures. The solid forms obtained were characterized by thermoanalytical techniques and X-ray diffraction. It was established the existence of three isomorphic crystalline habits and one semicrystalline form of saccharin, three pseudopolymorphic forms of sodium saccharin, two pseudopolymorphic forms of sodium cyclamate and two polymorphic form and one amorphous acesulfame-K.
3

Avaliação do comportamento térmico de habitações em San Antonio de Los Baños, Cuba / Evaluating thermal behavior of houses in San Antonio de Los Baños, Cuba

Silva, Adeildo Cabral da 07 June 2005 (has links)
A presente investigação teve por objetivo a avaliação de comportamento térmico de 14 habitações econômicas na comunidade de Las Mercedes, município de San Antonio de Los Baños, província de Havana, Cuba. As moradias foram construídas pelos próprios usuários dentro do Programa Iberoamericano de Ciencia Y Tecnologia para El Desarrollo - (CYTED) - SubPrograma XIV Tecnología para Viviendas de Interés Social - (HABYTED) Proyecto XIV.5 \"Con Techo\" - Programa (10X10). Considerando-se a gênese do clima de Cuba, foram definidos: o episódio representativo do fato climático (período de 27/04 a 13/05/2002), devido ao registro das mais elevadas temperaturas em Las Mercedes, San Antonio de Los Baños e, também, o dia representativo experimental (extraído do episódio representativo citado), a saber, dia 03/05/2002, com registro de mais elevado valor para temperatura externa (36,2ºC). Como procedimento para avaliação, as 14 casas foram divididas em três blocos: Bloco nº 1 (casas de dois pisos), Bloco nº 2 (mistas, dois pisos e térreas), Bloco nº 3 (térreas), em função da orientação da trajetória do sol e da direção do vento. O monitoramento e aquisição automática dos dados de superfície foram obtidos por meio de estação meteorológica Campbell Scientific CR10, durante o período de janeiro a dezembro de 2002, associados às condições sinóticas do clima local. Foram monitoradas duas variáveis internas das habitações, por meio de 14 sensores para monitorar a temperatura de bulbo seco (tbs) e 9 sensores para temperatura superficial (tsi). Os resultados indicam que as moradias do piso superior, com cobertura expostas a radiação solar global direta encontravam-se em desconforto térmico, (casas 2, 4 e 6, do bloco 1), com temperaturas internas superiores à externa; 11 casas puderam ser consideradas adequadas, em virtude dos registros de valores das temperaturas internas se apresentarem abaixo dos 36,2ºC (bloco 1: casas 1, 3 e 5; bloco 2: casas 7, 8, 10 e 11 e bloco 3: casas 12, 13 e 14). Portanto, depreende-se que existe adequação da maioria dos sistemas construtivos utilizados em Las Mercedes, em relação ao comportamento térmico em situação de calor. / The present research have purpose of thermal behavior evaluation of 14 economic houses at Las Mercedes community, San Antonio de Los Baños city, province of Havana, Cuba. The houses had been constructed by their users inside of Program Iberoamerican of Science and Technology for Development - (CYTED) - Subprogram XIV Technology for Social Interest Houses - (HABYTED) Project XIV.5 \"Con Techo\" - Program (10X10). Considering Cuba climate genesis, had been defined: the representative episode of climatic fact (from 27/04 to 13/05/2002), due register of the most raised temperatures at Las Mercedes, San Antonio de Los Baños and, also, the experimental representative day (from mentioned representative episode), it means, day 03/05/2002, registering of higher value for outdoor temperature (36,2ºC). As procedure for evaluation, the 14 housings had been divided in three blocks: Building block nº 1 (houses of two floors), Building block nº 2 (mixing, two floors and grounds), Building block nº 3 (grounds), in function of sun trajectory orientation and winds direction. Monitoring and automatic acquisition of surface data, they had been gotten by means of meteorological station Campbell Scientific CR10, during period from January to December, year of 2002, associates to synoptic conditions of local climate. Two indoor variables of those houses had been ensured, by means of 14 sensors for monitoring dry bulb temperature (tbs) and 9 sensors for monitoring superficial temperature (tsi). The results indicate that housings with two floors, with coverage receiving direct global solar radiation, were in thermal discomfort, (houses 2, 4 and 6, of building block 1), with indoor temperatures higher to outdoor one; 11 houses could be considered adjusted, due their values of indoor temperatures were below of 36,2ºC (building block 1: houses 1, 3 and 5; building block 2: houses 7, 8, 10 and 11, and building block 3: houses 12, 13 and 14). Therefore, it is inferred that there is satisfactoriness of the majority constructive systems used in 14 houses at Las Mercedes, in relation to thermal behavior about warm condition.
4

Estudo do polimorfismo dos edulcorantes artificiais sacarina, sacarina sódica, ciclamato de sódio e acesulfame-K / Study of polymorphism in artificial sweeteners saccharin, sodium saccharin, sodium cyclamte and acesulfame-K

Deyber Arley Vargas Medina 27 August 2013 (has links)
O polimorfismo nos edulcorantes artificiais sacarina, sacarina sódica, ciclamato de sódio e acesulfame-K foi estudado a partir da obtenção de cristais mediante evaporação lenta de solvente, em diferentes temperaturas e sistemas solventes. As formas sólidas obtidas foram caracterizadas mediante o emprego de técnicas temoanalíticas e de difração de raios X. Estabeleceu-se a existência de três hábitos cristalinos isomórficos e uma forma semicristalina de sacarina, três formas pseudopolimórficas de sacarina sódica, duas formas pseudopolimórficas de ciclamato de sódio e duas formas polimórficas e uma amorfa de acesulfame-K. / The polymorphism in the artificial sweeteners saccharin, sodium saccharin, sodium cyclamate and acesulfame-K was studied from crystals obtained by slow evaporation of solvent at different temperatures. The solid forms obtained were characterized by thermoanalytical techniques and X-ray diffraction. It was established the existence of three isomorphic crystalline habits and one semicrystalline form of saccharin, three pseudopolymorphic forms of sodium saccharin, two pseudopolymorphic forms of sodium cyclamate and two polymorphic form and one amorphous acesulfame-K.
5

Electrical and thermal behavior of Im7/977-3 Carbon fiber polymer matrix composites subjected to time-varying and steady electric currents

Deierling, Phillip Eugene 01 December 2010 (has links)
Electrical and thermal behavior of the carbon fiber polymer matrix composites subjected to time-varying and steady electric currents is studied. A fully automated experimental setup for real time measurements of the electric current, resistance, voltage, and temperature in carbon fiber polymer matrix composites has been developed. A series of electrical characterization tests on IM7/977-3 unidirectional and symmetric cross-ply composite laminates have been performed and the effects of electric current magnitude and duration, electrical resistance, and associated thermal effects have been investigated. It is determined that voltage-current relationship stays ohmic for up to 50 A steady currents, electrical resistance exhibits time-dependent behavior. It is also found that application of an electric current leads to a significant temperature rise in the composites that is a result of the intense Joule heat produced in the electrically conductive carbon fibers as well as in the composite-electrode contact.
6

Ανάπτυξη πολυλειτουργικών ινωδών σύνθετων υλικών οργανικής μήτρας με χρήση νανο-εγκλεισμάτων για τροποποίηση θερμικής τους συμπεριφοράς

Μπόγρη, Παναγιώτα 06 December 2013 (has links)
Σκοπός της παρούσας εργασίας ειδίκευσης ήταν η παρασκευή νανοσύνθετων υλικών οργανικής μήτρας, καθώς και η θεωρητική πρόβλεψη της θερμικής τους αγωγιμότητας. Στα πλαίσια της εργασίας πραγματοποιήθηκε η παρασκευή σύνθετων πολυμερικών υλικών εποξειδικής μήτρας, ενισχυμένων με δύο είδη νανοσωματιδίων ίδιας φύσης και διαφορετικής δομής (πολυφλοιϊκοί νανοσωλήνες άνθρακα - MWCNTs και πολυστρωματικά γραφένια - GNPs) καθώς και ένα τρίτο είδος νανοσωματιδίων διαφορετικής φύσης (νανοκαρβίδιο του πυριτίου - NanoSiC). Επίσης, πραγματοποιήθηκε η παρασκευή ινωδών σύνθετων υλικών (CFRP μονής διεύθυνσης και διάταξης [0]16) ενισχυμένων με δύο είδη νανοσωματιδίων (GNPs και MWCNTs). Για την παρασκευή των δοκιµίων εφαρμόστηκε η μέθοδος του «masterbatch», σύμφωνα με την οποία παρασκευάζεται ένα μίγμα εποξειδικής ρητίνης και νανοσωματιδίων, υψηλής κατά βάρος περιεκτικότητας, που αναδεύεται σε αναµίκτη υψηλών στροφών, υπό συνθήκες κενού, ελεγχόμενης θερµοκρασίας και ταχύτητας ανάµιξης. Από το «masterbatch», προσθέτοντας κάθε φορά, την επιθυμητή ποσότητα ρητίνης προέκυψαν μίγματα διαφόρων κατά βάρος περιεκτικοτήτων (1, 3, 5, 10 και 15% κ.β. σε GNPs - 1 και 3% κ.β. σε MWCNTs - 1, 3, 5 και 10% κ.β. σε NanoSiC). Το τελικό µίγµα εγχύθηκε σε καλούπια σιλικόνης και εισήχθη σε φούρνο, όπου ακολούθησε η διαδικασία πολυµερισµού για 2h σε θερμοκρασία 120°C. Τέλος, παρασκευάστηκαν πολύστρωτες πλάκες [0]16 πολυστρωματικών γραφενίων και πολυφλοιϊκών νανοσωλήνων άνθρακα αντιστοίχων περιεκτικοτήτων. Τα δοκίµια που προέκυψαν από την παραπάνω διαδικασία, χρησιμοποιήθηκαν για το χαρακτηρισμό της θερμικής αγωγιμότητας, με τη βοήθεια του Mathis Tci Analyzer. Από τη μελέτη των πειραματικών αποτελεσμάτων προέκυψε ότι η θερμική αγωγιμότητα των συνθέτων αυξάνεται, αυξανομένης της συγκέντρωσης των νανοεγκλεισμάτων. Επίσης, τα πολυστρωματικά γραφένια αποτελούν τη βέλτιστη ενίσχυση, σε σχέση με τα υπόλοιπα είδη νανοσωματιδίων που χρησιμοποιήθηκαν, για την βελτίωση της θερμικής αγωγιμότητας τόσο των νανοενισχυμένων πολυμερών όσο και των ινωδών συνθέτων, γεγονός το οποίο οφείλεται κυρίως στη δομή και τη γεωμετρία του. Επίσης, πραγματοποιήθηκε εφαρμογή επιλεγμένων θεωρητικών μοντέλων πρόβλεψης της εγκάρσιας θερμικής αγωγιμότητας, προκειμένου να διαπιστωθεί τυχόν σύγκλιση των θεωρητικών τιμών με τις πειραματικές τιμές. Από την μελέτη των θεωρητικών αποτελεσμάτων προέκυψε ότι το μοντέλο Lewis – Nielsen προβλέπει με τον βέλτιστο δυνατό τρόπο τη θερμική αγωγιμότητα των νανοενισχυμένων πολυμερών, ενώ το μοντέλο που ανέπτυξε ο Hashin τη θερμική συμπεριφορά των ινωδών σύνθετων υλικών. / The purpose of the present master thesis was the experimental and modeling study on the through-thickness thermal conductivity of epoxy nanocomposites. The first step was the dispersion of three different nanoparticles (Graphite-Nanoplatelets - GNPs, Multi Walled Carbon Nanotubes – MWCNTs, Nano-Silicon Carbide - NanoSiC) in a high volume fraction mixture, which is called «masterbatch». The manufacturing technique that was applied was mechanical high speed shearing. Then, «masterbatch» was used for the preparation of epoxy polymers of various volume fractions, reinforced with GNPs, MWCNTs and NanoSiC. Silicon molds were used for the fabrication of the polymer specimens. The polymerization profile was consisted of two hours in temperature 120°C. Moreover, two different types of carbon fiber-reinforced nanocomposites (Unidirectional – UD [0]16) were prepared, which were reinforced with GNPs and MWCNTs in corresponding volume fractions to polymers. The through-thickness thermal conductivity characterization was materialized through Mathis Tci Analyzer. Next, multiple theoretical models were evaluated to predict through-thickness thermal conductivity of both composite systems, and then compared to the experimental results. The results showed that high filler volume fractions heighten thermal conductivity. Moreover, Graphite – Nanoplatelet nanoparticles showed greater thermal conductivity than Carbon Nanotubes and Nano-Silicon Carbide, thanks to its structure and morphology. Lewis –Nielsen model was the appropriate one for the prediction of epoxy polymers, reinforced both GNPs and MWCNTs. Hashin model predicted the through thickness thermal conductivity of carbon fiber reinforced nanocomposites, reinforced both GNPs and MWCNTs.
7

Avaliação do comportamento térmico de habitações em San Antonio de Los Baños, Cuba / Evaluating thermal behavior of houses in San Antonio de Los Baños, Cuba

Adeildo Cabral da Silva 07 June 2005 (has links)
A presente investigação teve por objetivo a avaliação de comportamento térmico de 14 habitações econômicas na comunidade de Las Mercedes, município de San Antonio de Los Baños, província de Havana, Cuba. As moradias foram construídas pelos próprios usuários dentro do Programa Iberoamericano de Ciencia Y Tecnologia para El Desarrollo - (CYTED) - SubPrograma XIV Tecnología para Viviendas de Interés Social - (HABYTED) Proyecto XIV.5 \"Con Techo\" - Programa (10X10). Considerando-se a gênese do clima de Cuba, foram definidos: o episódio representativo do fato climático (período de 27/04 a 13/05/2002), devido ao registro das mais elevadas temperaturas em Las Mercedes, San Antonio de Los Baños e, também, o dia representativo experimental (extraído do episódio representativo citado), a saber, dia 03/05/2002, com registro de mais elevado valor para temperatura externa (36,2ºC). Como procedimento para avaliação, as 14 casas foram divididas em três blocos: Bloco nº 1 (casas de dois pisos), Bloco nº 2 (mistas, dois pisos e térreas), Bloco nº 3 (térreas), em função da orientação da trajetória do sol e da direção do vento. O monitoramento e aquisição automática dos dados de superfície foram obtidos por meio de estação meteorológica Campbell Scientific CR10, durante o período de janeiro a dezembro de 2002, associados às condições sinóticas do clima local. Foram monitoradas duas variáveis internas das habitações, por meio de 14 sensores para monitorar a temperatura de bulbo seco (tbs) e 9 sensores para temperatura superficial (tsi). Os resultados indicam que as moradias do piso superior, com cobertura expostas a radiação solar global direta encontravam-se em desconforto térmico, (casas 2, 4 e 6, do bloco 1), com temperaturas internas superiores à externa; 11 casas puderam ser consideradas adequadas, em virtude dos registros de valores das temperaturas internas se apresentarem abaixo dos 36,2ºC (bloco 1: casas 1, 3 e 5; bloco 2: casas 7, 8, 10 e 11 e bloco 3: casas 12, 13 e 14). Portanto, depreende-se que existe adequação da maioria dos sistemas construtivos utilizados em Las Mercedes, em relação ao comportamento térmico em situação de calor. / The present research have purpose of thermal behavior evaluation of 14 economic houses at Las Mercedes community, San Antonio de Los Baños city, province of Havana, Cuba. The houses had been constructed by their users inside of Program Iberoamerican of Science and Technology for Development - (CYTED) - Subprogram XIV Technology for Social Interest Houses - (HABYTED) Project XIV.5 \"Con Techo\" - Program (10X10). Considering Cuba climate genesis, had been defined: the representative episode of climatic fact (from 27/04 to 13/05/2002), due register of the most raised temperatures at Las Mercedes, San Antonio de Los Baños and, also, the experimental representative day (from mentioned representative episode), it means, day 03/05/2002, registering of higher value for outdoor temperature (36,2ºC). As procedure for evaluation, the 14 housings had been divided in three blocks: Building block nº 1 (houses of two floors), Building block nº 2 (mixing, two floors and grounds), Building block nº 3 (grounds), in function of sun trajectory orientation and winds direction. Monitoring and automatic acquisition of surface data, they had been gotten by means of meteorological station Campbell Scientific CR10, during period from January to December, year of 2002, associates to synoptic conditions of local climate. Two indoor variables of those houses had been ensured, by means of 14 sensors for monitoring dry bulb temperature (tbs) and 9 sensors for monitoring superficial temperature (tsi). The results indicate that housings with two floors, with coverage receiving direct global solar radiation, were in thermal discomfort, (houses 2, 4 and 6, of building block 1), with indoor temperatures higher to outdoor one; 11 houses could be considered adjusted, due their values of indoor temperatures were below of 36,2ºC (building block 1: houses 1, 3 and 5; building block 2: houses 7, 8, 10 and 11, and building block 3: houses 12, 13 and 14). Therefore, it is inferred that there is satisfactoriness of the majority constructive systems used in 14 houses at Las Mercedes, in relation to thermal behavior about warm condition.
8

Experimental study of a quench process

Zajc, David January 1998 (has links)
No description available.
9

Thermographic Measurements of Hot Materials Using a Low- to High-speed RGB-camera : Prospect of RGB-cameras Within the Field of Thermographic Measurements

Berndtsson, Therese January 2019 (has links)
Monitoring the thermal behavior of material while heated or cooled is of great importance in order to understand the structural behavior of materials. This thesis aims to investigate the prospects for imaging hot materials using an RGB-camera. The main motivation of using an RGB-camera is the very simple set-up and, in comparison to thermal IR-cameras, low price. A method and code enabling thermographic measurements in the temperature range of 800°C up to 1500°C has been produced. Calibration of the RGB-camera was made, the accuracy was predicted to be poor within the temperature range of 1000°C up to about 1200°C. The poor accuracy of the calibration within this range has its source in the non-linear (and irregular) response of the CMOS sensor prohibiting a valid exposure time function to be accurately determined. The calibration is thus performed with different settings (i.e different exposure times and aperture settings) but without any correction for the setting change. The validation experiments were performed in (or very close to) the temperatures where the temperature error was predicted to be the largest. An under-estimation of approximately 30-50°C in the temperature range between 950°C and 1015°C could be seen corresponding to an absolute error of about 3-5% in this temperature range. The accuracy is however thought to increase with the temperature above a temperature of approximately 1250°C . It is possible to perform a temperature transform of target images with temperatures above 1500°C since the Look-up-table produced for the temperature transform extends to about 3000°C . However, the accuracy is unknown since no calibration or validation experiments within these ranges were performed. The result of the calibration and experiments along with the theoretical assessment within the thesis gave background to the discussion of optimal imaging system for thermographic measurements. In order to receive more accurate temperature measurements, a CCD-sensor is to prefer since producing more uniform images with a more linear and predictable response. This would most likely enable the implementation of the camera setting influence. To receive better color accuracy but mainly to prevent channel overlap a system using three sensors instead of one (as for the current imaging system) is to prefer. This would result in larger freedom of channel choice and thus, the temperature transform can somewhat be customized for the specific measured temperature ranges. A brief discussion concerning the overall choice of camera was also brought up. Since the temperature range is large and the red, green and blue channels are sensitive to temperature changes the demands on the sensor dynamic range will be high in order to receive a linear response, or even a fully predictable response, across the whole temperature range. A suggested option to the RGB-camera, still offering the very simple set up, is a dual-wavelength camera in the near (or medium wavelength) infrared range. / Kartläggning av materialförändringar vid uppvärmning eller nedkylning är av stor betydelse för förståelsen för ett materials strukturella beteende. Denna masteruppsatts syftar till att utforska utsikterna för termisk avbildning av varma material med en RGB-kamera. I detta inkluderas kalibrering av kamera, validerings experiment och teoretiska efterforskningar. Det huvudsakliga motivet för användning av en RGB-kamera är den enkla uppställningen (endast en kamera där de olika färg-lagren är alignerade) och det, i jämförelse med många IR-kameror, låga priset. En metod och en kod som möjliggör termografiska mätningar (både video och stillbild) inom temperaturområdet 800°C till 1500°C har tagits fram där kalibrering av kameran är inkluderat. Efter utförd kalibrering förutspåddes att noggrannheten av mätningarna mest troligt skulle vara bristfälliga i området 1000°C upp till cirka 1200°C.  Denna bristfälliga noggrannheten har sin grund i den icke-linjära (och i vissa fall oregelbundna) sensorresponsen vilket, i huvudsak, försvårade bestämning av exponeringstidens signalinflytande. Med anledning av detta gjordes en kalibrering med fixa inställningar, det vill säga; fixa exponeringstider och bländarinställningar för mätningar inom specifika temperaturområden, men utan korrigering vid förändring av kamerainställningar. Valideringsexperimenten som utfördes var i (eller mycket nära) det temperaturområde där de största temperaturavvikelserna förutspåddes vara.  Utförd validering av metod för temperaturavbildning visade att mätningen med RGB-kameran underskattade temperaturerna med cirka 30-50°C i temperaturområdet mellan 975-1015° motsvarar ett absolut fel på cirka 3-5% inom detta temperaturområde. Det är dock troligt att noggrannheten av mätningarna ökar då temperaturerna av det avbildade objektet är större än 1250°C då man i kalibreringsprocessen kunde se mindre avvikelser i detta område.  Med producerad look-up table (skapad i kalibreringsprocessen) är det möjligt att utföra temperaturtransformationer för avbildningar av objekt som har temperaturer över 1500°C, dock med okända osäkerheter då varken kalibrerings- eller valideringsexperiment har utförts för så pass höga temperaturer.  Resultatet av kalibreringen och experimenten, tillsammans med en teoretisk utredning av begränsningar och möjliga förbättringar vid termografiska mätningar, lade grunden till diskussion gällande optimalt bildsystem. Rekommendationer för att i framtiden utföra mer exakta termografiska mätningar med en RGB-kamera togs fram där en 3-CCD kamera föreslogs för att förbättra mätresultaten.  En CCD sensor är att föredra framför en CMOS sensor då de icke-verkliga pixel-avvikelserna inte är lika kritiska för en CCD-sensor som för en CMOS-sensor. CCD-sensorn är dessutom i många aspekter mer tillförlitlig vid vetenskapliga mätningar och har oftast mer linjär och förutsägbar respons vilket mest troligt skulle möjliggöra inkludering av exponeringstidens signalinflytande.  En kort diskussion gällande val av kanaler (våglängdsområden) som kan användas vid temperaturmätningar tas även upp i avhandlingen. Eftersom temperatur-mätområdet är stort och den röda, gröna och blå kanalen är känsliga för temperaturförändringar (liten förändring av temperatur ger stor förändring i uppmätt emission) så kommer kravet på det dynamiska omfånget av sensorn vara högt.  Ett alternativ till RGB-kameran, som fortfarande har en enkel uppställning, är en dubbel-sensor-kamera med ett dubbelt bandpass-filter i det när-infraröda (NIR) området. Detta kräver dock en utredning för hur sensorer i detta område påverkar den uppmätta signalen.
10

Caracterização da farinha e do amido isolado da semente de jaca e comportamento reológico de dispersões de amido / Characterization of flour and isolated starch from seeds of jackfruit and rheological behavior of starch dispersions

Luciano, Carla Giovana 18 February 2016 (has links)
O amido é um ingrediente com grande versatilidade de aplicação, e as sementes de jaca, fruto bem difundido, porém pouco aproveitado no Brasil, contêm uma quantidade considerável de amido, sendo ainda fonte de ferro e proteínas. Dessa maneira, os objetivos desse projeto foram a obtenção da farinha de sementes de jaca das variedades mole e dura, a extração do amido utilizando diferentes solventes, e a caracterização de suas propriedades físico-químicas, estruturais e funcionais, bem como a caracterização reológica de dispersões/géis de amido em cisalhamento estacionário e oscilatório. A extração alcalina do amido, além de reduzir significativamente o conteúdo de lipídeos e proteínas, deixando o amido mais puro, promoveu um aumento no teor de amilose e influenciou diretamente as características de inchamento e solubilidade, que apresentaram aumento significativo a partir da temperatura de 70 °C. O aumento da temperatura ocasionou aumento no poder de inchamento e solubilidade, que foi mais pronunciado para a variedade dura, porém esses valores ainda foram considerados baixos (< 17%). Os amidos de sementes de jaca apresentaram grânulos lisos, arredondados e em forma de sino, com formato mais truncado para o amido extraído com hidróxido de sódio. O diâmetro médio dos grânulos de amido foi menor para a extração alcalina, mas sempre com comportamento monomodal. Foi observado um padrão de difração de Raios-X do tipo A para todas as amostras estudadas, e o índice de cristalinidade foi maior para os amidos de sementes de jaca dura, com uma redução estimada em 70% para os amidos obtidos por extração alcalina. A temperatura de gelatinização dos amidos de semente de jaca foi considerada alta (70-100 °C). Os amidos de sementes de jaca dura obtidos na extração com água apresentaram maiores valores de viscosidade de pico e de Breakdown, que representa menor resistência mecânica. A extração com solução de NaOH 0,1 M aumentou a tendência a retrogradação de ~36% (extração aquosa) para 64% e 45% dos amidos de sementes de jaca das variedades mole e dura, respectivamente. Todas as amostras apresentaram comportamento pseudoplástico (n < 1) nas concentrações e temperaturas estudadas, e as dispersões e/ou géis de amido obtidos pela extração alcalina com NaOH apresentaram menor tixotropia e maiores valores de viscosidade. Os modelos Lei da Potência e Herschel Bulkley apresentaram ótimos ajustes aos pontos experimentais (R² ~0,998) para as amostras com 2 e 6 % de amido, respectivamente, porém para a concentração de 5%, o melhor modelo foi função da variedade do fruto usado na obtenção do amido. A dependência das propriedades reológicas com a temperatura foi analisada pela equação de Arrhenius e a energia de ativação foi baixa (15-25 kJ/mol). Quanto ao comportamento viscoelástico, as amostras com 5 e 6% de amido apresentaram comportamento de gel fraco e o aumento da concentração desse polissacarídeo produziu um aumento na elasticidade do material. Os módulos de armazenamento (G\') associados à elasticidade do gel de amido aumentaram durante o seu resfriamento nos ensaios de varredura de temperatura, o que pode ser relacionado à recristalização da amilose durante esse processo e mantiveram-se praticamente constantes no aquecimento isotérmico a 80 °C, sugerindo boa estabilidade térmica do gel. A farinha isolada da semente de jaca pode ser considerada fonte de fibras e apresentou elevados teores de proteínas (~14-16%) e ferro (~85-150 mg/kg). A distribuição do tamanho de partículas da farinha apresentou comportamento bimodal, com grânulos arredondados, presença de fibras e uma matriz proteica envolvendo os grânulos de amido. As propriedades de pasta revelaram maior pico de viscosidade para a farinha de semente de jaca mole. As características encontradas sugerem que os amidos de semente de jaca poderiam ser aplicados na produção de filmes biodegradáveis, e a farinha da semente de jaca poderia ser utilizada em substituição parcial à farinha convencional na fabricação de bolos e biscoitos. / Starch is an ingredient with great versatility of application, and the seeds of jackfruit, a well spread fruit but little exploited in Brazil, contain a considerable amount of starch, being a source of iron and proteins. Thus, the aimes of this project were to obtain the jackfruit seed flour of hard and soft varieties, extraction of starch using different solvents and characterization of its physicochemical, structural and functional properties, as the rheological characterization of dispersion/gels starch under steady and oscillatory shear. Alkaline extraction of starch significantly reduced the content of lipids and proteins, leaving to a purest starch, and promoted an increase in amylose content, besides, directly influenced the swelling and solubility characteristics, which showed a significant increase from the temperature of 70 ° C. The increase in temperature caused an increase in the power of swelling and solubility, which was more pronounced for the hard variety, but these values are still considered low (<17%). Jackfruit seeds starch granules showed smooth, rounded, bell-shaped, and they had more truncated form when starch was extracted with sodium hydroxide. The average diameter of the starch granules was lower for alkaline extraction, but always with monomodal behavior. It was observed diffraction pattern of X-rays of type A for all samples, and the crystallinity index was higher for the starches of hard jackfruit seeds with an estimated reduction of 70% to starches obtained by alkaline extraction. The gelatinization temperature of starches jackfruit seed was considered high (70-100 °C). The hard jackfruit seed starches obtained in the aqueous extraction had higher peak viscosities and Breakdown, what means lower mechanical strength. Extraction with 0.1 M NaOH solution increased the retrogradation of ~ 36% (aqueous extraction) to 64% and 45% of jackfruit seed starch varieties of soft and hard, respectively. All samples exhibited pseudoplastic behavior (n <1) at the concentrations and temperatures studied, and starch dispersions and /or gels obtained by alkaline extraction with NaOH showed lower thixotropy and higher viscosities. Power Law and Herschel Bulkley models showed great adjustments to the experimental points (R² ~ 0.998) for samples with 2 and 6% starch, respectively, but for the concentration of 5%, the best model was a function of the fruit variety used on starch extraction. The dependence of the rheological properties with temperature was examined by the Arrhenius equation and activation energy was low (15-25 kJ / mol). In concern to the viscoelastic behavior, samples of 5 and 6% of starch showed a behavior of weak gel and the increase in concentration of this polysaccharide produced an increase in the elasticity of the material. The storage modulus (G \') associated with the elasticity of the starch gel increased during its cooling in the temperature sweep tests, which may be related to the recrystallization of amylose during this process and remained practically constant in the isothermal heating at 80 °C, suggesting good thermal stability of the gel. The isolated jackfruit seed flour may be considered source of fiber and showed high levels of proteins (~ 14-16%) and iron (~ 85-150 mg / kg). Particle size distribution of the flour showed bimodal behavior with rounded beads, fibers and the presence of a protein matrix surrounding the starch granules. Pasting properties revealed higher peak viscosity for the soft jackfruit seeds flour. The characteristics found suggest that jackfruit seed starch could be applied in the production of biodegradable films, and jackfruit seed flour could be used in partial replacement of conventional flour in the manufacture of cakes and cookies.

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