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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.
171

Efeito da germinação de grão e temperatura de processamento na composição nutricional de dietas crudívoras / Effect of grain germination and processing temperature on the nutritional composition of raw food diets

Fiori, Carolina Bonfanti 18 July 2014 (has links)
A busca por um estilo de vida saudável tem motivado diversos indivíduos a mudanças em seus hábitos alimentares. O crudivorismo, também conhecido por alimentação viva ou alimentação crua (raw food) destaca-se dentre as demais dietas vegetarianas devido aos seus fundamentos, princípios e estilo de vida. Os crudívoros se abstêm de aplicação térmica, pois argumentam que as comidas cruas contem as próprias enzimas digestivas que facilitam a digestão dos alimentos no organismo. Para evitar possíveis deficiências e interferências nutricionais e manter dieta predominantemente crua, os crudívoros necessitam de planejamento adequado e seleção de alimentos apropriados. O presente estudo tem por objetivo verificar a adequação nutricional de uma dieta crudívora composta por vegetais, grãos germinados, alimentos de diferentes fontes lipídicas e submetidas a três temperaturas de processamento. O preparo das dietas crudívoras e as análises químicas foram realizados no laboratório de Nutrição Humana, do Departamento de Agroindústria, Alimentos e Nutrição da Escola Superior de Agricultura \"Luiz de Queiroz\". Para a elaboração das dietas crudívoras foi utilizado uma dieta base, constituído de batata com casca, tomate vermelho cru, couve crua com talos e suco de limão. A esta dieta base foram acrescidas lentilha germinada ou lentilha não germinada e a estas amostras, amendoim germinado ou azeite de oliva. Posteriormente foram submetidas a diferentes temperaturas de processamento, 25 ºC, 40 ºC e 80 ºC. Os grãos de lentilha e amendoim foram germinados por 24 horas sob ausência de luz. As dietas foram classificadas como D1 (dieta base; lentilha germinada; azeite de oliva), D2 (dieta base; lentilha germinada; amendoim germinado), D3 (dieta base; lentilha não germinada; azeite de oliva) e D4 (dieta base; lentilha não germinada; amendoim germinado). O processo de germinação e o tratamento térmico interferiram nos teores da maior parte dos nutrientes analisados. A inclusão de lentilha germinada nas dietas crudívoras proporcionou o incremento nos teores de umidade, cinzas, carboidrato, fibra solúvel, vitamina C, cálcio, ferro dialisável e níquel dialisável e redução nos teores de proteína, fibra insolúvel, taninos, capacidade antioxidante por DPPH e ABTS. As dietas crudívoras a 25ºC apresentaram maiores teores de cinzas, taninos e cálcio e menores concentrações de ácido fítico, em contra partida, as dietas a 80 ºC apresentaram teores superiores de fibra solúvel, ácido fítico, vitamina C, capacidade antioxidante por DPPH e ABTS, boro, manganês, ferro dialisável e cálcio dialisável. As dietas crudívoras submetidas a 80 ºC apresentaram valores de referência de Coliformes a 45 ºC, Bacillus cereus, Staphylococcus aureus e Samonella de acordo com resolução vigente. No entanto, as dietas a 25 ºC e 40 ºC apresentaram quantidade superior ao limite máximo estabelecidos dos microrganismos analisados. Pode ser observado que a inclusão de grãos germinados proporcionou maiores alterações nutricionais nas dietas crudívoras que o tratamento térmico. / The search for a healthy lifestyle has motivated many individuals to change their eating habits. The crudivorism, also known as living nourishment or raw food, stands out among the other vegetarian diets due to its fundaments and principles. The adepts of a raw food diet abstain from eating heated food, arguing that raw nutriment contains digestive enzymes that facilitate food digestion in the body. To avoid nutritional deficiencies, nutritional interferences and maintain a predominantly raw diet, proper planning is required, as well as a good selection of appropriate nourishment items. The present study aims at determining the nutritional adequacy of a raw food diet consisted of vegetables, germinated grains and foods of different lipid sources, which were subjected to three processing temperatures. The preparation of the raw food diets and its consequent chemical analyzes were performed in the Human Nutrition laboratory of the Department of Agroindustry, Food and Nutrition from the School of Agriculture \"Luiz de Queiroz\". For the formulation of such raw food diets, it was used a basis diet consisting of potato with peeling, raw tomato, raw kale with stalks and lemon juice. To this diet it was added germinated or non-germinated lentils and, to these samples it was added germinated peanuts or olive oil. Subsequently, they were subjected to different processing temperatures, 25º C, 40ºC and 80ºC. The lentil grains and peanuts had been germinated for 24 hours in absence of light. The diets were classified as D1 (basis diet; germinated lentils; olive oil), D2 (basis diet; germinated lentils, germinated peanuts), D3 (basis diet, nongerminated lentils, olive oil) and D4 (basis diet; non-germinated lentils, germinated peanuts). The germination process and heat treatment interfered on most of the compositions of the analyzed nutrients. The inclusion of germinated lentils into raw food diets provided the increase in moisture, ashes, carbohydrates, soluble fiber, vitamin C, calcium, dialyzable iron, dialyzable nickel as well as reduction of proteins, insoluble fiber, tannins and antioxidant capacity by DPPH and ABTS. Raw food diets at 25°C presented higher levels of ashes, tannins and calcium and lower levels of phytic acid. On the other hand, the diets at 80°C presented higher concentration of soluble fiber, phytic acid, vitamin C, antioxidant capacity by DPPH and ABTS, boron, manganese, dialyzable iron and dialyzable calcium. Raw food diets subjected to 80°C presented remarkable levels of Coliforms at 45ºC, Bacillus cereus, Staphylococcus aureus and Salmonella, according to the current resolution. Nevertheless, diets at 25ºC and at 40ºC presented levels that were higher than the established limits to the analyzed microorganisms. It could be observed that the inclusion of germinated grains to raw food diets yielded higher nutritional changes than did the submission to heat treatment.
172

Produção e caracterização de filmes finos de GeO2-PbO. / Production and characterization of thin films of GeO2-PbO.

Hora, Windson Gomes 05 November 2008 (has links)
Este trabalho apresenta a produção e a caracterização de filmes finos produzidos a partir da técnica de RF Magnetron Sputtering. Foram produzidos filmes finos sobre substrato de silício a partir de alvos vítreos de germânio de GeO2-PbO preparados com e sem os reagentes AgNO3 e Cu2O. Foi desenvolvida metodologia adequada para a obtenção de nanopartículas em filmes finos por meio de tratamento térmico. Os filmes foram caracterizados por técnicas de perfilometria, elipsometria, Microscopia de Força Atômica (AFM), Rutherford Backscattering (RBS), Microscopia Eletrônica de Transmissão (TEM) e medidas elétricas para a obtenção das curvas de capacitância e corrente em função da tensão. Os valores dos índices de refração medidos ficaram em torno de 1,9, isto é, próximo do valor do alvo vítreo utilizado para as deposições. Através do AFM foi observado que a rugosidade vale-pico variou de 2 a 4 nm. Através de TEM verificou-se em todos os filmes a presença de nanopartículas metálicas e também facetas cristalinas formadas pelos próprios elementos da matriz. Pelas medidas elétricas, foram obtidos os resultados das constantes dielétricas que variaram com o tratamento térmico. Os valores variaram de 8 a 15 superando o valor do SiO2 que é de 3,9. Com todos os resultados elétricos, foi notado que o filme preparado com o reagente CU2O foi o que apresentou maior estabilidade com o tratamento térmico o que é adequado para o preparo de dispositivos MOS. Neste caso o valor obtido para a constante dielétrica foi de 14. / This work presents the production and characterization of thin films produced by the RF Magnetron Sputtering technique. There were produced thin films on silicon substrate from vitreous targets of GeO2-PbO prepared with and without AgNO3 and Cu2O reagents. It was developed adequate methodology to obtain metallic nanoparticles in thin films by means of heat treatment. The films were characterized using perfilomitry, ellipsometry, Atomic Force Microscopy (AFM), Rutherford Backscattering (RBS), Transmission Electron Microscopy (TEM) techniques and electrical measurements in order to obtain the curves of current and capacitance as a function of the voltage. The values of refractive indices were measured around 1.9 next to the value of the vitreous target used for the deposition. Through the AFM, it was observed that the valley-peak roughness varied from 2 to 4 nm. Through TEM, it was observed in all films the presence of metallic nanoparticles and also some crystalline faces formed by the elements of the matrix. With the electrical measurements, there were obtained the dielectric constants that varied with the heat treatment. The values ranged from 8 to 15 surpassing the value of SiO2 which is 3.9. With all the electric results, it was noted that the film prepared with copper was the one that presented the highest stability with the heat treatment that is appropriate for the preparation of MOS devices.
173

Estudo das transições morfológicas na decomposição da austenita utilizando um par de difusão Fe-5%Ni/Fe-10%Ni. / Study of the morphological transitions in austenite decomposition using a Fe-5%Ni/Fe-10%Ni diffusion couple.

Eduardo Franco de Monlevade 18 December 2012 (has links)
No presente trabalho, foram estudados os aspectos morfológicos da decomposição da austenita em função da variação dos teores de níquel e carbono. Para a realização deste estudo, foi preparado um par de difusão composto de ligas Fe-5%Ni e Fe-10%Ni. O par foi feito por co-laminação a quente, e amostras deste par foram carburadas até teores de carbono de 0,1%, 0,3%, 0,5%C e 0,7%C. As amostras foram austenitizadas a 900°C por 20 minutos e tratadas isotermicamente por 10 minutos a temperaturas entre 400°C e 500°C por 10 minutos. Nas ligas hipoeutetóides, os produtos de decomposição da austenita predominantes são perlita degenerada, bainita inferior e ferrita degenerada. A perlita degenerada foi observada nas amostras tratadas a 500°C, nas regiões de baixo níquel, juntamente com a bainita superior. À medida em que se avança para regiões de mais alto níquel, a formação de perlita degenerada cessa, sendo a bainita o único produto de decomposição. A bainita dá então lugar à formação de ferrita degenerada, isenta de carbonetos, em regiões de teor de níquel próximo de 7%. Nas amostras tratadas a 400°C, o principal produto de decomposição da austenita é a bainita inferior, cuja escala se torna progressivamente mais grosseira com o aumento do teor de níquel. Foi observado um produto de decomposição eutetóide que pode ser caracterizado como bainita nodular, mas que só ocorre em estágios avançados dar reação de decomposição da austenita. Análises de difração de elétrons retroespalhados revelam que a ferrita degenerada é composta de múltiplas partículas de ferrita, que têm entre si uma diferença de orientação cristalográfica de até 8°. Nas ligas hipereutetóides, os produtos de decomposição da austenita são perlita e bainita inversa. Com a diminuição da temperatura de tratamento, nota-se uma diminuição na formação de perlita, sendo esta totalmente suprimida a 400°C. Em todas as amostras tratadas, a decomposição da austenita não foi completa após 10 minutos de tratamento térmico, independente da temperatura de tratamento. / In the present work, the morphological aspects of austenite decomposition were studied as related to Ni and C. To perform this study, a diffusion couple composed of Fe-5%Ni and Fe-10%Ni was produced. The couples were produced by hot co-rolling, and carburized to carbon contents of 0.1%C, 0.3%C, 0.5%C and 0.8%C. The samples were solution treated in the austenitic range at 900°C for 20 minutes, and held isothermally at temperatures between 400°C and 500°C for 10 minutes. In the hypoeutectoid alloys, the austenite decomposition products are degenerate pearlite, bainite (upper and lower), and degenerate ferrite. Degenerate pearlite was observed in the samples treated at 500°C and 450°C, and only in the low-nickel regions, along with upper bainite. With increasing nickel content, the formation of degenerate pearlite ceases, and bainite is the only decomposition product. Bainite is then replaced by degenerate ferrite, free of carbides, at nickel contents close to 7%. In the samples treated at 400°C, the main decomposition product is lower bainite, with a progressively coarser scale as the nickel content rises. A nodular decomposition product was observed, which can be identified as nodular bainite, occurring only at advanced stages of reaction in samples treated at 400°C. Electron backscatter diffraction analyses reveal that degenerate ferrite is characteristically composed of multiple ferrite particles, containing a crystallographic misorientation of up to 8°. In hypereutectoid alloys, the decomposition products are pearlite and inverse bainite. As the treatment temperature is diminished, a decrease in the amount of pearlite formed is observed, and pearlite is completely suppressed at 400°C. In all samples treated, the reaction was incomplete after 10 minutes, regardless of the temperature of isothermal hold.
174

Development of Computer Aided Heat Treatment Planning System for Quenching & Tempering (CHT - q/t) and Industrial Application of CHT-bf & CHT-cf

Singh, Amarjit Kumar 03 May 2006 (has links)
Heat treatment can be defined as a combination of heating and cooling operations applied to a metal or alloy in solid state. It is an important manufacturing process, which controls the mechanical properties of metals, therefore contributes to the product quality. Computerized Heat Treatment Planning System for Quenching and Tempering (CHT-q/t), a windows based stand alone software, is developed to assist the heat treatment process design. The goal of CHT-q/t is to predict the temperature profile of load in batch as well as continuous furnace during heating, quenching and tempering of steel, then to predict the mechanical properties as Quenched & Tempered, and finally to optimize the heat treatment process design. The thesis reviews existing heat treating simulation software and identifies the industrial need of a software tool which integrates part load and furnace model with heat treating process. The thesis discusses cooling curve of specimen and Time Temperature Transformation (TTT) diagram to determine the microstructure evolution and subsequently the mechanical properties of steel after quenching. An extensive database has been developed to support the various function modules. The thesis focuses mainly in the TTT and quenchant database development, property prediction after quenching and tempering and the implementation of software. The properties determined in the thesis are hardness, ultimate tensile strength, yield strength, toughness and percentage elongation. Hardness has been predicted by the use of some well known analytical equations and the TTT database, finally regression analysis has been used to give the value as a function of carbon percentage and volume fraction of martensite. The other mechanical properties are calculated based on a relation of hardness and volume fraction of martensite. Various case studies were performed to show the application of CHT-bf and CHT-cf at Bodycote Thermal Processing, Worcester & Waterbury. The objective behind the case studies was to study the effect of change in load arrangement, production rate and cycle time on the heat treated parts and finally to give recommendations in order to save energy and improve productivity and quality.
175

Investigation of the quench and heating rate sensitivities of selected 7000 series aluminum alloys

Nowill, Courtney Ann 13 August 2007 (has links)
"The quench sensitivity of AA7136 has been experimentally investigated using Jominy end quench and test coupons of various heat treatments. It was found that this alloy is not quench sensitive. In addition, the effects of heating rate on both solution and aging treatments on AA7136 and AA7075 were determined using a newly developed reverse Jominy heating test. It was observed that hardness was reduced after rapid heating during aging and hardness increased slightly after rapid heating during solutionizing. These results are discussed in terms of microstructural developments. "
176

The Effects of Rust on the Gas Carburization of AISI 8620 Steel

Wang, Xiaolan 31 July 2008 (has links)
"The effects of rust on the carburization behavior of AISI 8620 steel have been experimentally investigated. AISI 8620 steel samples were subjected to a humid environment for time of 1 day to 30 days. After the exposure, a part of the samples was cleaned by acid cleaning. Both cleaned and non-cleaned samples have been carburized, followed by quenching in mineral oil, and then tempered. To determine the effect of rust on gas carburizing, weight gained by the parts and the surface hardness were measured. Surface carbon concentration was also measured using mass spectrometry. Carbon flux and mass transfer coefficient have been calculated. The results show that acid cleaning removes the rust layer effectively. Acid cleaned samples displayed the same response to carburization as clean parts. Rusted parts had a lower carbon uptake as well as lower surface carbon concentration. The surface hardness (Rc) did not show a significant difference between the heavily rusted sample and clean sample. It has been observed that the carbon flux and mass transfer coefficient are smaller due to rust layer for the heavily rusted samples. These results are discussed in terms of the effects of carbon mass transfer on the steel surface and the resulting mass transfer coefficient."
177

De-lubrication during sintering of P/M compacts: Operative mechanism and process control strategy

Saha, Deepak 01 October 2004 (has links)
"De-lubrication is the first stage in a sintering operation, where the lubricants (higher weight hydrocarbons) are removed from the parts by controlled heating. Improper de-lubrication leads to defects such as blistering, sooting, micro-porosity etc in a sintered part. Most of these problems arise, as there exists a gap in the present understanding of de-lubrication. The primary motive of this work is to direct research towards the development of sensors and controls and thus, mitigate the various problems due to improper de-lubrication. Currently, there exists a myriad of lubricants being used during the process of compaction. They include metallic based lubricants, polymers and non-metallic lubricants. In this work, research was limited in understanding the de-lubrication of EBS (Ethylene Bisstearimide), as, it the most commonly used lubricant in the industry. It has replaced commonly used lubricant due to cleaner burnouts, absence of metallic residue and, cost effectiveness. The entire work is divided into three phases: • Phase 1: Ascertained the most important parameters that affect the kinetics of de-lubrication. • Phase 2: Investigated the type of gases released during the decomposition of EBS. • Phase 3: Recommended a control strategy. TGA (Thermo-gravimetric analysis) was used in the phase I, the results clearly show that the rate of heating is the most important parameter during de-lubrication. Identification of gases was performed using the FTIR (Fourier transform infrared spectroscopy) and DUV (Deep ultraviolet spectroscopy). This constituted the second phase of our experiments. The primary gases identified in Phase II were carbon dioxide and a hydrocarbon (hepta-decane). Finally, an empirical model for de-lubrication has been proposed in Phase III. The model was verified in an industrial furnace. It has been observed that there exists a very good correlation between the proposed empirical model and the experiments performed in Phase II of this study. This study lays down the following guidelines for the development of future sensors and controls: • The development of future sensors should focus in the detection of CO2 and hepta-decane. • Rate of heating determines how fast or slow the lubricant decomposes and finally escapes form the compacted part. • The empirical model may be used, as a means to determine the time a part should reside in a furnace for complete lubricant burnout at a given heating rate."
178

Quench Probe and Quench Factor Analysis of Aluminum Alloys in Distilled Water

Fontecchio, Marco 29 April 2002 (has links)
A 6061 aluminum probe was quenched with the CHTE probe-quenching system in distilled water while varying bath temperature and the level of agitation. Time vs. temperature data was collected during the quench by use of an ungrounded K-type thermocouple embedded inside the probe. Cooling rates and heat transfer coefficients, h, were calculated and Quench Factor Analysis (QFA) was also performed to quantitatively classify the quench severity. The data showed an increase in both maximum cooling rate and heat transfer coefficient and a decrease in the Quench Factor, Q, as bath temperature decreased and agitation level increased. Maximum heat transfer coefficient values ranged from 1000 W/m2K to 3900 W/m2K while maximum cooling rates of 50¡ÃƒÂ£C/s to 190¡ÃƒÂ£C/s were achieved. In addition, it was found that at higher levels of agitation, there was also an increase in the variation (i.e. standard deviation) of the cooling rate and therefore h and Q.
179

Caracterização físico-química de filmes finos de ftalocianinas metálicas / Physical-chemical characterization of fine films of metal phthalocyanines

Scheidt, Wanessa Fernanda 24 October 2018 (has links)
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2019-03-21T18:49:10Z No. of bitstreams: 1 Wanessa_Scheidt_2018.pdf: 2637303 bytes, checksum: fd114adf03634dc5d338b2141788ea64 (MD5) / Made available in DSpace on 2019-03-21T18:49:10Z (GMT). No. of bitstreams: 1 Wanessa_Scheidt_2018.pdf: 2637303 bytes, checksum: fd114adf03634dc5d338b2141788ea64 (MD5) Previous issue date: 2018-10-24 / The search for new materials with physicochemical properties for use in devices and sensors are reasons for the study of metal phthalocyanines. Phthalocyanines are highly conjugated macrocyclic compounds of blue or green color and high thermal and chemical stability. They are very used in the formation of fine films well ordered by the casting method. Generally, phthalocyanines exhibit ptype semiconductor properties, but substitutions in their peripheral rings may alter this n-type semiconductivity. Fluorinated phthalocyanines have presented films with good molecular organization, attracting attention to study in solar cells. This work deals with the formation of thin films, using the casting technique, of zinc hexadecafluorophthalocyanines (F16ZnPc) and cadmium (F16CdPc), and the investigation of crystallinity in these films. The objectives of the work were: to analyze the solubility of the compounds the solubility of the compounds in volatile organic solvents; prepare thin films on glass substrates coated with fluorine-doped tin oxide (FTO) and characterize them before and after the heating. Absorption spectroscopy in the ultraviolet-visible (UV-Vis.) region, for solutions of these compounds, have shown that the solvent may influence the observation of the monomeric or dimeric forms. The films show spectra with wider bands and formation of type J aggregates. Changes observed after the heat treatment, carried out at 300 oC for 3 h, suggest the reordering of the molecules on the substrates. Atomic force microscopy (AFM) images showed that there was an elongated preferential arrangement in F16CdPc films and some loss of material for F16ZnPc. Scanning electron microscopy (SEM) crystallites were observed for F16CdPc, but few changes have been observed for F16ZnPc. X-ray diffraction (XRD) results revealed crystalline films, where rings could have different orientations on the substrate. However, after heating, they may have adopted a single orientation, called face on, where the molecules would be in a horizontal position in relation to the substrate. / A busca por novos materiais com propriedades físico-químicas para uso em dispositivos e sensores são motivos para o estudo de ftalocianinas metálicas. As ftalocianinas são compostos macrocíclicos altamente conjugados de coloração azul ou verde e alta estabilidade térmica e química. São muito utilizadas na formação de filmes finos bem ordenados pelo método casting. Geralmente, as ftalocianinas apresentam propriedades semicondutoras do tipo-p, porém substituições em seus anéis periféricos podem alterar essa semicondutividade para tipo-n. Ftalocianinas fluoradas têm apresentado filmes com boa organização molecular, atraindo atenção para estudo em células solares. Este trabalho aborda a formação de filmes finos, usando a técnica casting, das hexadecafluoroftalocianinas de zinco (F16ZnPc) e cádmio (F16CdPc), e a investigação da cristalinidade nesses filmes. Os objetivos do trabalho foram analisar a solubilidade dos compostos em solventes orgânicos voláteis, preparar filmes finos sobre substratos de vidro recoberto com óxido de estanho dopado com flúor (FTO) e caracterizar os mesmos antes e após aquecimento. Espectroscopia de absorção na região do ultravioleta-visível (UV-Vis.), para soluções desses compostos, mostraram que o solvente pode influenciar na observação das formas monomérica ou dimérica. Os filmes apresentam espectros com bandas mais alargadas e formação de agregados tipo J. Alterações observadas após o tratamento térmico, realizado a 300 oC por 3 h, sugerem reordenamento das moléculas sobre os substratos. As imagens de microscopia de força atômica (AFM) mostraram que houve uma organização preferencial alongada em filmes da F16CdPc e alguma perda de material para a F16ZnPc. Nas imagens de microscopia eletrônica de varredura (MEV) foram observados cristalitos para a F16CdPc, porém poucas alterações foram observadas para a F16ZnPc. Resultados de difração de raio X (DRX) revelaram filmes cristalinos, onde anéis apresentariam diferentes orientações sobre o substrato, podendo ter passado para uma única orientação após aquecimento, denominada face on, onde as moléculas estariam em posição horizontal em relação ao substrato.
180

Paleocoastal Resource Use and Human Sedentism in Island Environments: A Case Study from California's Northern Channel Islands

Jew, Nicholas 03 October 2013 (has links)
The peopling of the Americas, including the possibility that maritime peoples followed a coastal route from Northeast Asia into the New World, is a topic of major interest in archaeology. Paleocoastal sites on California`s Northern Channel Islands (NCI), dating between ~13,000 and 8000 years ago, may support this coastal migration theory. Until recently, however, we knew little about Paleocoastal technologies, settlement, and lifeways on the islands. Combining traditional archaeological approaches with experimental and archaeometric techniques, I examine Paleocoastal settlement and resource use on San Miguel and Santa Rosa islands. Recently discovered Paleocoastal sites have produced sophisticated chipped stone technologies, with bifacially-flaked points and crescents of extraordinary craftsmanship. Exploring lithic raw material procurement strategies, I demonstrate a Paleocoastal preference for island cherts from sources centered on western Santarosae. Using experimental and archaeometric techniques, I show that Paleocoastal peoples systematically employed heat-treatment to manufacture finely crafted bifaces from island cherts. Using stable oxygen isotope (δ18O) analyses of marine shells from Paleocoastal sites, I examine paleo-sea surface temperatures, seasonality of shellfish collecting, and human sedentism. Evaluating whether such occupations were seasonal or year-round, I tested different sampling strategies for California mussel shells, showing that a method used by many California archaeologists provides erroneous seasonality interpretations for ~35 percent of sampled shells. Using a more intensive sampling strategy, I demonstrate that some Paleocoastal sites were used seasonally, but three substantial middens dating to 8200, 9000, and 10,000 cal BP produced evidence for shell harvesting during all four seasons. This suggests that the NCI were occupied more or less permanently and year-round by at least 10,000 years ago. My research suggests that Paleocoastal peoples had a strong commitment to maritime and island lifeways starting at least 12,000 years ago. From that time until ~8000 years ago, Paleocoastal peoples relied primarily on island resources despite their close proximity to the mainland. The presence of a relatively large, permanent, and distinctive Paleocoastal population on the NCI may also support the coastal migration theory and an even deeper antiquity of human settlement and sedentism on the NCI. This dissertation includes previously published and unpublished co-authored material.

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