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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.
121

Do extrativismo à domesticação: as possibilidades da castanha-do-pará / From extraction to domestication: the possibilities of Brazil nut

José Jonas Almeida 04 March 2015 (has links)
Uma das mais importantes atividades econômicas da Amazônia, a extração da castanha-do-pará foi o sustento de muitas populações tradicionais daquela região. Vários estudos têm destacado as suas qualidades nutritivas e as boas possibilidades de uso para esse produto. Desde a década de 1960, avançaram no Brasil as pesquisas para o aperfeiçoamento do cultivo da castanheira, algo que havia sido tentado pelos ingleses, desde a primeira metade do século XIX. Os institutos de pesquisas agrícolas do Brasil conseguiram, após décadas de estudos, desenvolver a técnica de plantio da espécie, que requer as condições de seu ambiente original, necessárias ao desenvolvimento da planta. Por outro lado, pouco foi feito no sentido de melhorar o beneficiamento e o aproveitamento do produto, ainda muito limitado ao uso da amêndoa. Atualmente, a castanha-do-pará é vista como um recurso que pode contribuir para a preservação da floresta amazônica e, ao mesmo tempo, gerar renda para as populações da região. / One of the most important economic activities in the Amazon, the extraction of Brazil nut, was responsible for the livelihood of many traditional peoples of that region. Several studies have highlighted the nuts nutritional qualities and its good possibilities of use. Since the 1960s, researches have increased in Brazil to improve the cultivation of Brazil nut trees, something that had already been tried by the Englishmen since the first half of the 19th century. Agricultural research institutes in Brazil have succeeded to develop the technique, which requires the plants original environmental conditions in order to thrive. On the other hand, little has been done to improve the products processing and use, which is still limited to the kernel. Today, Brazil-nut is seen as a resource that can contribute to the preservation of the Amazon rainforest and at the same time generate income for the people of the region.
122

Atividade de óleos essenciais sobre espécies de Aspergillus spp. aflatoxigênicas isoladas de castanha do Brasil / Activity of essential oils on aflatoxigenic species of Aspergillus spp. isolated from Brazil nuts

Possari, Camila Kopezky, 1987- 09 October 2014 (has links)
Orientador: Marta Cristina Teixeira Duarte / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-26T00:07:11Z (GMT). No. of bitstreams: 1 Possari_CamilaKopezky_M.pdf: 2524622 bytes, checksum: e715e6d4f298fb93b3325792c5427282 (MD5) Previous issue date: 2014 / Resumo: A castanha do Brasil (Bertholletia excelsa H.B.K.) é a segunda mais importante fonte extrativista da floresta amazônica. Desta forma, não são utilizados defensivos químicos e a produção da castanha do Brasil é considerada orgânica tendo sua extração ambientalmente correta, porém este baixo nível tecnológico favorece o crescimento de fungos potencialmente produtores de micotoxinas como os do grupo Aspergillus section flavi. Visando reduzir esta contaminação, uma das possibilidades é a utilização de óleos essenciais, que apresentam propriedades antimicrobianas. Assim, o objetivo do presente trabalho foi avaliar a atividade antifúngica de 11 óleos essenciais de espécies medicinais e aromáticas sobre cepas aflatoxigênicas de A. flavus, A. nomius e A. arachidicola isoladas de castanha do Brasil. O ensaio de microdiluição mostrou que os óleos que apresentaram melhor atividade antifúngica contra estes os isolados foram Cinnamomum burmannii e Eugenia caryophyllata, com MIC de 250 'mu'g/mL e 500 'mu'g/mL, respectivamente. A inibição do crescimento micelial dos fungos foi melhor quando estes foram submetidos à ação por contato com os óleos essenciais, do que por ação de seus compostos voláteis, sendo as concentrações referentes às de MIC capazes de inibir totalmente o crescimento dos fungos. A produção de aflatoxina por A. flavus foi inibida somente pelo óleo essencial de E. caryophyllata, na concentração de 500 'mu'g/mL. Ensaios in vivo conduzidos com a casca da castanha do Brasil mostraram que o óleo essencial de C. burmannii inibiu o fungo a 500 'mu'g/mL e propiciou maior redução na porcentagem de infecção pelos isolados de A. flavus. Quanto aos isolados de A. nomius e A. arachidicola, a menor porcentagem de infecção foi obtida após tratamento com o óleo essencial de E. caryophyllata na concentração de 1000 'mu'g/mL. Os óleos de E. caryophyllata e C. burmanni mostraram ser alternativas naturais para controle do crescimento de A. flavus, A. nomius e A. arachidicola e da produção de aflatoxinas por A. flavus, através da ação na redução da contaminação fúngica das castanhas do Brasi / Abstract: The Brazil nut (Bertholletia excelsa H.B.K.) is the second most important forest source of the Amazon rainforest. Thus, no chemical pesticides are used and the production of Brazil nuts is considered organic and an environmentally friendly extraction. However, this low technological level favors the growth of potentialy mycotoxin producing fungi such as Aspergillus section flavi. In order to reduce this contamination, one possibility is the use of essential oils that exhibit antimicrobial properties. The objective of this study was to evaluate the antifungal activity of 11 essential oils of medicinal and aromatic species on aflatoxigenics strains of Aspergillus flavus, A. nomius and A. arachidicola isolated from Brazil nuts. The microdilution assay showed that the oils from Cinnamomum burmannii and Eugenia caryophyllata presented the best antifungal activity against all isolates, with MIC of 250 'mu'g/mL and 500 'mu'g/mL, respectively. The inhibition of mycelial growth of the fungi was better when submitted to action by contact than by action of oils volatile compounds, with concentrations of MIC able to completely inhibit the growth of fungi. The aflatoxin production was inhibited only by E. caryophyllata essential oil at a concentration of 500 'mu'g/mL . In vivo assays conducted with shells of Brazil nut showed that the essential oil of C. burmannii at 500 'mu'g/mL provided greater reduction in the percentage of infection by A. flavus isolates. As the isolates of A. nomius and A. arachidicola, the infection rate was lower after the treatment with the essential oil of E. caryophyllata in the concentration of 1000 'mu'g/mL. The essential oils of E. caryophyllata and C. burmannii showed to be natural alternatives for controlling the growth of A. flavus, A. nomius and A. arachidicola and aflatoxin production by A. flavus, through the reduction of the fungal contamination of Brazil nuts / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos
123

The development of pictograms for use on food products containing nuts / Framtagning av piktogram för användning på livsmedelsprodukter som innehåller nötter

Emin, Yad, Nilsson, Victoria January 2014 (has links)
Denna studie undersöker hur märkning på livsmedelsförpackningar kan göras tydligare för personer med nötallergi. Tidigare studier visar att det finns brister i dagens märkningar och att detta i sin tur skapar problem. Därför har denna studie som avsikt att ta reda på hur allergeninformation för nötallergiker kan förbättras och göras tydligare. Detta tillämpas genom att studiens forskare tar fram ett designförslag som ska komplettera obligatorisk märkning på livsmedelsförpackningar. För att ta reda på hur detta designförslag ska utformas inleds designprocessen med en litteraturstudie och där en cross-case-analys genomförs. Genom denna analys hittas trender och mönster i tidigare studier. Därefter tillämpas en design space-analys där trenderna, olika designprinciper samt forskarnas egna kunskaper kombineras för att utforska olika designalternativ. Alternativ som i slutändan skapar en grund för en design. Studiens forskare skapar symboler, närmare bestämt piktogram. Eftersom jordnötsallergi och nötallergi är olika typer av allergier skapas två stycken piktogram. Piktogrammen, som är cirkelformade, får ett varnande budskap som förmedlas med hjälp av färgerna gul och svart. Piktogrammen utvärderas och testas genom att fem personliga intervjuer genomförs. Intervjuerna görs med personer som är allergiska mot jordnötter och/eller nötter. Forskarna testar piktogrammen genom att placera dem på en livsmedelsförpackning och ställer sedan frågor om bl.a. första intryck, färger och placering. Analysen visar att piktogram mycket väl kan användas som kompletterande märkning på livsmedelsförpackningar. Vidare konstateras det att valet av färg inverkar på den association som sändaren vill förmedla. Intervjuerna visar även att piktogrammen fördelaktigt kan placeras på förpackningens framsida. Studiens syfte har uppnåtts till viss mån, då intervjuerna visar att det ena piktogrammet behöver utvecklas för att tydligare kommunikation för nötallergiker ska kunna skapas.
124

The Optimization of the Nuclear Protein in Testis (NUT) Antibody and its Importance and Impact in the Pathology Lab

Martinez, Lindsey 03 April 2017 (has links)
Optimization in immunohistochemistry is often a time consuming and complex process. There are a varying array of moving parts to consider all while preserving the sensitivity and specificity of the test. When optimizing an antibody it is important to consider the fixation of the tissue and the type of epitope retrieval that would be best suited for the test. The dilution of the primary antibody is a key marker for the efficiency and effectiveness of the laboratory protocol. The purpose of this study was to produce an optimized antibody for the nuclear protein in testis to detect NUT midline carcinoma that provides a sensitive and specific test but is also efficient and can be useful for everyday pathological dedications. The midline carcinoma defined by the translocation of the NUT gene on chromosome 15q14 that bonds with BRD4 or BRD3 commonly known as NUT midline carcinoma (NMC) is a rapidly aggressive and fatal disease. Commonly a fluorescent in situ hybridization (FISH) test is used to diagnosis this carcinoma. This test takes longer than traditional IHC and can delay the treatment of the patient. Therefore this is why, irrespective of the levels of tumor markers, immunohistochemistry for the NUT marker should be performed in any case where there is poorly differentiated carcinomas that do not have glandular differentiation that come from midline structures.
125

Criação do banco de dados, simulação e análise energética do processo de produção do biodiesel de soja, mamona e pinhão manso / Datanbank creation, simulation and energetic analysis of biodiesel production process from soybean, castor and physic nut

Miranda, Júlio César de Carvalho, 1983- 18 August 2018 (has links)
Orientador: Rubens Maciel Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-18T13:17:05Z (GMT). No. of bitstreams: 1 Miranda_JulioCesardeCarvalho_M.pdf: 5447186 bytes, checksum: 673a48d41a839dc0293c2ea573c40fad (MD5) Previous issue date: 2011 / Resumo: O biodiesel é um combustível produzido a partir de fontes renováveis, atóxico e livre de enxofre. Apesar de ser uma alternativa possível aos combustíveis fósseis, os dados relacionados ao biodiesel e principalmente à simulação de processos são escassos. Para que isso fosse superado foi construído a partir de métodos de contribuição de grupos e dados experimentais um banco de dados próprio para a simulação do processo de produção do Biodiesel a partir dos óleos de Soja, Pinhão Manso e Mamona. A partir da composição inicial dos triacilgliceróis presentes nos três óleos foram calculadas propriedades como: Temperatura Crítica, Pressão Crítica, Pressão de Vapor, Energia Livre de Gibbs de Formação Padrão, Entalpia de Formação. Os óleos virtuais foram testados em um mesmo layout de simulação com o objetivo de comparar energeticamente as três fontes de matéria-prima, esse layout promoveu a inserção de um vaso flash para prover o reciclo do etanol para o sistema. Foram testadas também outras duas mudanças de layout de simulação. Nos casos da soja e da mamona, respectivamente, duas colunas de destilação e uma retirada lateral na coluna de destilação. Os resultados obtidos foram de grande significância, pois foi possível comparar as três matérias-primas e os três layouts de simulação de forma adequada, sendo os melhores resultados obtidos para a soja. No entanto, se pode desconsiderar tecnicamente o uso do Pinhão Manso e da Mamona, fontes que não competem com commodities alimentícias e possuem alta produtividade no Brasil / Abstract: Biodiesel is a fuel made from renewable sources, nontoxic and sulfur free. Despite being a possible alternative to fossil fuels, the data related to biodiesel and especially to the process simulation are scarce. To overcome this, was constructed, using group contribution methods and experimental data, a database suitable for the simulation of the production process of biodiesel from soybean oil, castor and physic nut oils. From the initial composition of triacylglycerols present in the three oils were calculated properties as: Critical Temperature, Critical Pressure, Vapor Pressure, Gibbs Free Energy of Formation of Standard Enthalpy of Formation. The virtual oils were tested within a same simulation layout in order to compare the energetically the three raw material sources, this layout has promoted the inclusion of a flash drum to provide the recycling of ethanol into the system. Were also tested two other changes on simulation layout in cases of soybean and castor oil, respectively, two distillation columns and one lateral withdraw in the distillation column. The results were especially significant because it was possible to compare the three raw materials and the three layouts simulated adequately, and the best results obtained for soybean, however, technically not disregarding the use of physic nut and castor, sources that do not compete with food commodities and have high productivity in Brazil / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
126

Estabilidade oxidativa de óleo extra-virgem de castanha do Pará com ervas aromáticas antioxidantes / Oxidative stability of crude Brazil nut oil whith antioxidant aromatic herbs

Cristiane Zago Zácari 11 August 2008 (has links)
Com a finalidade de inibir ou retardar a oxidação lipídica de óleos, gorduras e alimentos gordurosos são empregados compostos químicos conhecidos como antioxidantes. Recentemente, o interesse na adição de aditivos em alimentos derivados de plantas tem aumentado, deste modo, o uso de ervas e seus extratos têm mostrado possuir propriedades tanto para a preservação da saúde como dos alimentos . O emprego de ervas aromáticas como antioxidantes naturais tem se destacado na indústria de alimentos, quer na forma de extratos, quer in natura. Cinco ervas, desidratadas em escala laboratorial e industrial, de reconhecido poder antioxidante, orégano, Origanum vulgare; manjericão, Ocimum basilicum; coentro, Coriandrum sativum L.; salsa, Petrosolium sativum e tomilho, Tymus vulgaris, foram avaliadas quanto ao teor de compostos fenólicos, umidade e quanto à atividade antioxidante através de teste acelerado de oxidação, Schaal Oven Test, e armazenamento em temperatura ambiente, em óleo de castanha do Pará a partir da s análises de índice de peróxido, absortividade específica em 232 nm, índice de acidez, índice de iodo, estabilidade oxidativa e perfil de ácidos graxos. O teor de fenólicos e umidade encontrado variou entre as ervas. Orégano, coentro, salsa e manjericão s ecos industrialmente, apresentaram os maiores teores de compostos fenólicos. O tomilho não apresentou diferença entre as amostras. O tomilho e o orégano foram as ervas que apresentaram as maiores concentrações de compostos fenólicos independentemente do pr ocesso de secagem. Nos testes de estufa as ervas tomilho e orégano foram as que demonstraram maior atividade. Em relação aos testes de estufas todas as combinações apresentaram resultados satisfatórios, mas esses resultados não se repetiram quando o experi mento foi realizado em temperatura ambiente . Apesar de a atividade antioxidante das ervas poder ser relacionada à presença dos compost os fenólicos, poucos estudos têm considerado os efeitos da sua interação. / With the purpose to inhibit or to delay the lipid oxidation, oil, fats and fatty foods chemical composites are used known as anti oxidant. Recently, the interest in the additive addition in foods derived from plants has increased, in this way the us e of herbs and extracts has shown some preservation properties of health and foods. The rule of natural aromatic herbs as antioxidant has been detached in the food industry using the extract and in natura forms. Five herbs, dehydrated in laboratorial and industrial scale, of recognized antioxidant capability, oregano, Origanum vulgare; basil, Ocimum basilicum; sage, Coriandrum sativum L.; parsley, Petrosolium sativum and thyme, Tymus vulgaris, had been evaluated on phenolic contents levels, humidity and antioxidant activity through a sped up test of oxidation, Schaal Oven Test, and storage at ambient temperature added to Brazil nut oil by means of peroxide value, specific extinction in 232 nm, acid value, iodine index, oxidative stability and fatty acid composition. Phenolic levels and moisture found between herbs varied. Oregano, sage, parsley and basil industrially dried, had shown the highest phenolic composite levels. Thyme had not shown any difference between the samples. Thyme and oregano had been the herbs that have shown the highest phenolic composite concentrations independently of the drying process. In the oven stability tests thyme and oregano had been the ones that had demonstrated the highest activity. In relation to the tests of greenhouses all the combinations had presented satisfactory results, but these results had not occurred again when in ambient temperature. Although antioxidant activity of herbs is related to the presence of phenolic composites few studies has considered the effect of its interaction.
127

Lisímetros de pesagem direta para o estudo do consumo hídrico do pinhão-manso (Jatropha curcas L.) / Direct weighing lysimeters to study the crop water use by physic nut (Jatropha curcas L.)

Flumignan, Danilton Luiz 07 February 2012 (has links)
Nos últimos anos tem aumentado o interesse no uso do pinhão-manso (Jatropha curcas L.) como fonte de óleo para a produção de biodiesel. No entanto, o conhecimento atualmente disponível sobre o consumo hídrico desta cultura é escasso e constitui um dos principais fatores limitantes no seu uso como alternativa agroenergética. Somado a isso, acredita-se que o aumento da produção de biodiesel no mundo irá aumentar a pressão sobre os recursos hídricos, o que torna necessário utilizar a água na agricultura da forma mais eficiente possível. Assim, este estudo teve como objetivo construir seis lisímetros de pesagem direta que serão utilizados para estudar o consumo hídrico do pinhão-manso irrigado por pivô central, gotejamento e sem irrigação. Esses lisímetros foram calibrados e testados quanto a sua sensibilidade a temperatura do ar e vento. Além disso, comparou-se a influência do uso de duas células de carga diferentes na qualidade dos mesmos. Na área de cada tratamento foram instalados dois lisímetros, sendo um utilizando células de carga ALFA® e outro HBM®. Cada lisímetro foi constituído por tanques de aço carbono de 1,955 m de raio interno (12 m2) e 1,3 m de profundidade útil. Estes foram circundados por paredes de concreto, possuíam sistema de drenagem e se encontravam diretamente apoiados sobre três células de carga. Ambos os modelos das células apresentavam capacidade nominal de 10.000 kg, sendo a capacidade combinada do lisímetro de 30.000 kg. Os lisímetros foram calibrados adicionando e, depois, retirando 1.000 kg de massa dos mesmos. Os dados foram usados para ajustar um modelo de regressão linear entre a massa acumulada e a média do sinal de saída das três células de carga. No teste de sensibilidade à temperatura, a massa dos lisímetros foi monitorada por até dois dias consecutivos, sob condição de massa constante e com proteção para não haver interferência do vento. Os dados foram comparados com a temperatura registrada na estação meteorológica e, também, com a temperatura medida pelo datalogger e um termohigrômetro, os quais foram instalados no fosso dos lisímetros. Para a avaliação da sensibilidade ao vento, foram construídos protótipos de árvores usando tubos de PVC e lonas de ráfia. Em cada lisímetro instalou-se uma árvore e, sob condição de massa constante, a massa dos mesmos foi monitorada por seis dias consecutivos. Os dados obtidos foram comparados com a velocidade do vento medida na estação meteorológica. Todos os lisímetros construídos neste estudo apresentaram qualidade suficiente para serem usados na determinação da evapotranspiração em escala horária e diária. Nos lisímetros ALFA®, a resolução final das medidas foi de 0,0013 mm, sendo realizadas com boa precisão, apresentando histerese e baixa acurácia (erro padrão entre 0,27 e 1,04 mm). Os lisímetros HBM® apresentaram resolução final de 0,00088 mm, boa precisão, pouca ou nenhuma histerese e alta acurácia (erro padrão entre 0,03 e 0,1 mm). Todos os lisímetros demonstraram não sofrer influência da temperatura e do vento na determinação da evapotranspiração, embora, em ambos, ALFA® e HBM®, a precisão das medidas foi reduzida linearmente com o aumento da velocidade do vento. / Recently, there is an increasing interest in using physic nut (Jatropha curcas L.) as a source of oil for biodiesel production. However, currently knowledge regarding its crop water requirement is scarce and constitutes one of the main gaps that limit its use as an agroenergy alternative. In addition, there is a general agreement that an increase in biodiesel production worldwide will bring additional pressure to water resources, what provokes to use water in agriculture in a more efficient way. So, this study had as objective to construct six direct weighing lysimeter that will be used to study the water use of physic nut conducted under sprinkler and drip irrigation, and without irrigation. These lysimeters were calibrated and tested for its sensibility to air temperature and wind. Furthermore, there was also compared the influence of using two different load cells on their quality. Two lysimeters were installed for each treatment, one using ALFA® load cells and other using HBM®. Each lysimeter was constituted by a steel tank with 1.955 m inner radius (12 m2) and 1.3 m of usable depth. They were encompassed by concrete walls, have a drainage system and were directly supported by three load cells. Both load cell models has a nominal capacity of 10,000 kg, with a lysimeter summed capacity of 30,000 kg. Lysimeters calibration procedure was done by adding and, after it, removing 1,000 kg of mass from then. Data were used to fit a linear regression model between the accumulated mass and the mean output value of the three load cells. For testing the sensibility to temperature, lysimeters mass were monitored till two consecutive days, under constant mass and with a barrier for protecting against wind interference. Data were compared to the temperature measured by the weather station and, also, by that measured by a datalogger and a thermohygrometer, which were installed inside the lysimeters pit. For testing to wind sensibility, there were constructed some trees prototypes using PVC pipes and raffia tarpaulin. One tree was installed on each lysimeter and, under constant mass, lysimeters mass were monitored during six consecutive days. Data were compared to the wind velocity, as measured by the weather station. All the six lysimeters constructed in this study presented adequate quality to be used for the determination of evapotranspiration on hourly and daily basis. For ALFA® lysimeters, the final measurement resolution was 0.0013 mm, being obtained with good precision, hysteresis, and low accuracy (standard error of 0.27 to 1.04 mm). HBM® lysimeters presented a final resolution of 0.00088 mm, good precision, few or no hysteresis, and high accuracy (standard error between 0.03 and 0.1 mm). All lysimeters proved to be not influenced by air temperature and wind on the determination of evapotranspiration, in spite of, in both, ALFA® and HBM® lysimeters, their measurement precision was linearly reduced with an increase in wind velocity.
128

Synthesis, characterization and application of amine-modified Macadamia nutshell adsorbents and ion imprinted polymers for the sequestration of Cr(VI) ions from aqueous solution

Nchoe, Obakeng Boikanyo 08 1900 (has links)
M. Tech (Department of Chemistry, Faculty of Applied and Computer Sciences) Vaal University of Technology. / Persisting challenges associated with remediation of heavy metals from aqueous media have stirred the need for enhancement of current technologies. Cellulosic agro waste materials (AWM) as well as ion-imprinted polymers (IIP) have received ardent attention from researchers. These materials are often employed in the following industries: water and wastewater treatment, medical, pharmaceutical and packaging. Applications in water and wastewater treatment have gained significant interest due to desirable features they possess. In the case of AWM, these features include a tuneable surface area and poor porosity, basic surface functional groups and chemical stability. Some desired features in IIP include adsorption sites compatible for the ion imprint obtained after leaching with suitable reagents, rigidity and reusability. The efficacy of employing AWM and IIP for the remediation of toxic chromium from aqueous solution was explored. The current study is made up of part A and B. In part A, Macadamia nutshell powder was treated using HNO3, NaOH, as well as Fenton’s reagent. The three materials underwent a new modification which involved reacting treated adsorbents with cetyltrimethylammonium chloride (CTAC), followed by immobilization of 1,5' diphenylcarbazide (DPC) ligand. The adsorbents were ultimately washed, dried and stored for Cr(VI) batch adsorption experiments. Part B involved a synthesis of IIP and their non-imprinted polymer counterpart (NIP) for Cr(VI) sequestration in aqueous solution. This was done by precipitation polymerization of functional monomers, crosslinker and DPC-Cr(VI) complex as a template. Non-imprinted polymers were fashioned in a manner like that of IIP but with the exclusion of Cr(VI) ion template. Characterizations of the adsorbents were done using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray fluorescence (XRF), and carbon, hydrogen, nitrogen and sulphur (CHNS) analyzer. Batch adsorption experiments were done and parameters such as solution pH, adsorbent dosage, initial Cr(VI) concentration and contact time were optimized. Working solutions were analyzed using ultraviolet-visible (UV-Vis) and atomic absorption (AA) spectroscopy. Adsorption parameters found to be optimum for DPC immobilized cellulosic adsorbents were pH 1.4, adsorbent mass of 0.1 g, 100 mg/L initial concentration and 125 minutes of contact time. The adsorption parameters determined to be optimum for IIP and NIP were pH 2.6, 0.2 g adsorbent mass, 80 mg/L initial concentration and 240 minutes of contact time. Reusability studies demonstrated the potential of adsorbents to remove Cr(VI) ions from aqueous media after successive adsorption-desorption cycles. Selectivity studies indicated that DPC immobilized adsorbents as well as IIP were able to selectively adsorb Cr(VI) ions from aqueous media in the presence of Zn(II), Cu(II), Co(II) and NI(II) ions. Kinetic models revealed that DPC immobilized cellulosic adsorbents and synthetic IIP were most fitting for pseudo-second order and pseudo first order, respectively. On the other hand, adsorption isotherm studies demonstrated that DPC immobilized cellulosic adsorbents and synthetic polymers were best fit for Freundlich and Langmuir adsorption isotherm, respectively.
129

Macadamia nutshell powder grafted with 1,5’-diphenylcarbizide for enhanced removal of Cr(VI ) from aqueous solution

Maremeni, Londolani Charity 08 1900 (has links)
M. Tech (Department of Chemistry, Faculty of Applied and Computer Sciences) Vaal University of Technology. / Agricultural waste such as Macadamia nutshells are currently receiving more attention for removal of hexavalent chromium (Cr(VI)). However, they have low adsorption capabilities when used in their raw form. In this study, the efficiency of using Macadamia nutshell powder modified with different concentrations of hydrogen peroxide, grafted with 1,5’-diphenylcarbizide (DPC) for the removal of hexavalent chromium from aqueous solution was explored. The effects of various parameters controlling adsorption of Cr(VI) onto Macadamia adsorbents such as initial concentration, contact time, adsorbent concentration and pH were investigated. The optimal operating parameters for Macadamia nutshells treated with hydrogen peroxide (MHP) adsorbents were determined to be 75 mg/L, 3 h, 0.1 g and pH 1. The optimal operating parameters for Macadamia nutshells treated with hydrogen peroxide and grafted with 1,5’-diphenylcarbizide (MHPD) were determined to be 150 mg/L, 1 h, 0.1 g and pH 3. Fourier transform infrared (FTIR) spectroscopy of the adsorbents revealed that treated MHP showed amino groups attached to the adsorbents. Thermogravimetric analysis (TGA) revealed that the grafted material lowered the thermal stability from 180◦C to 300◦C due to volatile nature of DPC. The surface of the MHPD materials was rough due to grafting. The results showed that the 1,5’-diphenylcarbazide treatment improved the removal efficiency of Cr(VI).
130

Charakterizace sýrových analogů vyrobených s přídavkem ořechového oleje / Characterization of cheese analogues produced with addition of nut oil

Mitra, Michal January 2020 (has links)
This thesis deals with the production and characterization of cheese analogues, i.e. products where some of the dairy components are partially or completely replaced by a non-dairy component. Model samples – Eidam type cheese and analogue with the addition of pistachio oil, were produced by a conventional technological process at MENDELU in Brno. Free and bound fatty acids, volatile substances and sensory quality were selected and monitored as the main characterizing parameters of the sample quality. The aim was to characterize the differences between the samples caused by the addition of nut oil in the monitored parameters. The HS-SPME-GC-MS method was used for the identification and semi-quantification of volatiles. The extraction of fats from the samples was performed with a mixture of solvents (diethyl ether, petroleum ether), fatty acids were converted to methyl esters by acid esterification with methanolic solution of boron trifluoride as a catalyst and subsequently identified and quantified by GC-FID. Descriptive scales and comparisons with standard were used to sensory evaluate the appearance, color, texture, odor, taste, and overall acceptability of the samples. The structure was monitored by electron microscopy. The results show that the addition of pistachio oil affects the sensory properties, the maturation process (higher content of volatile substances), the nutritional value (increased content of unsaturated fatty acids) and the stability of the product.

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