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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

Extração supercritica dos oleos volateis de Achyrocline sautereioides (Macel) e Vetiveria zizanioides (Vetiver) : determinação da cinetica de estração e estimativa de custos de manufatura / Supercritical extraction of volatile oils from Achyrocline sautereioides (Macel) and Vetiveria zizanioides (Vetiver) : determination of extraction kinectics and cost of manufacturing estimation

Vasconcellos, Claudia Monica Cabral de 30 July 2007 (has links)
Orientador: Maria Angela de Almeida Meireles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T22:01:09Z (GMT). No. of bitstreams: 1 Vasconcellos_ClaudiaMonicaCabralde_M.pdf: 1343433 bytes, checksum: 8d0e348f337a691c19dd2508ad30b2f7 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho foi estudado o comportamento cinético e custos de manufatura de extratos vegetais processados por tecnologia supercrítica. Foram determinados os parâmetros cinéticos do processo em diferentes condições de temperatura e pressão, foi avaliada a composição química dos extratos e foram estimados os custos de manufatura. Foram estudadas duas plantas: Achyrocline satureioides (Macela) e Vetiveria zizanioides (Vetiver). O custo de manufatura do óleo de vetiver apresentou grande influência do tempo de extração, apresentando-se menor para menores ciclos de extração. Devido ao alto investimento na planta de extração e baixo custo das matérias primas, era esperado que o mínimo custo de manufatura coincidisse com o tCER. Dessa forma, como no caso do vetiver parte significativa do extrato é obtida nos primeiros minutos de extração, os menores custos de manufatura ocorrem com os menores ciclos de extração. A estimativa de custos obteve resultados de custos a partir de US$ 24 / kg de extrato / Abstract: In this work, the kinetic behavior and manufacture costs of vegetal extract processed by supercritical technology were studied. The kinetic parameters of the process in different conditions of temperature and pressure were determined, the chemical composition of extracts was evaluated and the manufacture costs were estimated. Two plants were studied: Achyrocline satureioides (Macela) and Vetiveria zizanioides (Vetiver). The manufacture cost of the vetiver oil presented great influence of the extraction time, resulting in lower costs for lower extraction cycles. Due to the high required investment in the extraction plant and low cost of the raw material, it was expected that the minimum cost of manufacture coincided with the tCER. Thus, as considering vetiver extraction process significant part of the extract it is obtained in the first minutes of the process, the lower costs of manufacture occur with lower cycles of extraction. The estimate of manufacture costs resulted in values as low as 24 US$/kg of extract / Mestrado / Mestre em Engenharia de Alimentos
2

Caractérisation chimique et biologique de trois huiles essentielles répulsives issues de la biodiversité régionale contre l'alphavirus du Ross River / Chemical and biological characterization of three repellent essential oils from regional biodiversity against Ross River alphavirus

Ralambondrainy, Miora 27 September 2017 (has links)
Les huiles essentielles de citronnelle (Cymbopogon citratus), de géranium (Pelargonium graveolens) et de vétiver (Vetiveria zizanioides) sont utilisées partout dans le monde pour leur activité répulsive contre les principaux vecteurs (moustiques, tiques) de maladies infectieuses chez l'Homme (paludisme, chikungunya, …). L'application cutanée de ces produits naturels pour éviter le contact avec un vecteur n'avait pas été encore envisagée comme moyen de limiter les premiers stades de l’infection par l'agent pathogène transmis par le vecteur. Pour vérifier cette hypothèse, les travaux ont été consacrés à la mise en place d'un cadre structuré pour la réévaluation chimique et biologique des trois huiles essentielles sur le modèle du virus du Ross River (alphavirus) de la même famille que le virus du Chikungunya. La caractérisation chimique des huiles essentielles avec une technique de haute résolution (GC×GC/TOF-MS) a permis d'établir leur profil chémotypique précis. L'utilisation de marqueurs spécifiques (clones moléculaires du virus) a permis d'établir l'inhibition de la réplication virale en fonction des conditions d'application des huiles essentielles de géranium et citronnelle. Ces résultats suggèrent l'intérêt d’une huile essentielle répulsive dans les premiers stades d'une infection par un vecteur. À ce titre, l'étude comparative établit la haute valeur ajoutée de l'huile essentielle de géranium et oriente la recherche de nouveaux anti-infectieux naturels vers des complexes riches en monoterpènes. / Essential oils of citronella (Cymbopogon citratus), geranium (Pelargonium graveolens) and vetiver (Vetiveria zizanioides) are used worldwide as topical repellent against the main vectors (mosquitoes, ticks) of human infectious diseases (Malaria, chikungunya, …). Skin treatment with these natural products, initially to avoid contact with the vector had not yet been considered as a way to disrupt the early stages of infection when the repelling action fails. To check this hypothesis, a structured framework has been performed for the chemical and biological re-evaluation of the three essential oils. The latter was tested against Ross River virus (alphavirus) that belongs to the same family of Chikungunya virus. Analysis of essential oils using a high-resolution technique (GC × GC / TOF-MS) resulted in a more accurate chemotypical profile of the local production. The use of specific markers (molecular clones of the virus, Saclay CEA) allowed to establish the inhibition of viral replication depending of the conditions of geranium and citronella essential oils application. These results suggest the great interest of an essential oil topical repellent in the early stages of a vector infection. The comparative study established the high value of geranium essential oil and gave future direction to the discovery of new anti-infectious solutions from monoterpenes-rich natural complexes.
3

Application of ecological technology for removal of COD, nitrogen and phosphorus from piggery wastewater after biogas production technology

Vu, Thi Nguyet, Tran, Van Tua, Dang, Dinh Kim, Bui, Thi Kim Anh, Vu, Hai Yen 07 January 2019 (has links)
Despite a positive contribution to economic – social development, the growth of piggeries has caused heavily environmental pollution. Currently, treated wastewater of pig farms unfortunately does not meet the national discharge standards yet. This paper presents some research results on the removing COD, nitrogen and phosphorus in piggery wastewater after anaerobic (biogas) process at pilot scale by the combined system using Phragmites australis, Cyperus alternifolius, Vetiveria zizanioides and Eichhornia crassipes. The experimental results showed that the wastewater loading rate of 47.35 l/m2.day with initial concentrations of 203.24 mg COD/l, 111.94 mgTN/l and 13.61 mgTP/l gave removal efficiency of 71.66 %, 79.26 % and 69.65 %, respectively. Thus, the removed quantity of total nitrogen (TN) and total phosphorus (TP) was of 4201.35 mg TN/m2.day và 448.76mg TP/m2.day. The obtained results indicated that the flow wetland system, using Phragmites australis, Cyperus alternifolius, Vetiveria zizanioides and Eichhornia crassipes has a rather high COD, TN and TP removal efficiency with simple operation so that it could be feasible if applied for treating pig wastewater. However, the system should be functioned longer for taking data and for evaluating its stability. / Mặc dù có những đóng góp tích cực cho sự phát triển kinh tế - xã hội, việc phát triển chăn nuôi lợn đã gây ô nhiễm môi trường nghiêm trọng. Hiện nay, nước thải chăn nuôi lợn từ các cơ sở chăn nuôi sau xử lý vẫn chưa đáp ứng được các tiêu chuẩn thải của quốc gia và tiêu chuẩn ngành. Bài báo này trình bày kết quả nghiên cứu về khả năng loại bỏ COD, nitơ (N) và phôtpho (P) trong nước thải chăn nuôi lợn đã qua xử lý bằng hầm biogas của hệ thống phối hợp cây Sậy, Thủy Trúc, cỏ Vetiver và Bèo Tây ở qui mô pilot. Kết quả thực nghiệm ở tải lượng 47,35 l/m2.ngày, với COD, tổng nitơ (TN) và tổng phôtpho (TP) đầu vào trung bình là 203,24 mg/l, 111,94 mg/l và 13,61 mg/l, tương ứng, thì hiệu suất xử lý lần lượt là 71,66 %; 79,26 % và 69,65 %. Như vậy lượng TN và TP loại bỏ là 4201,35 mgN/m2.ngày và 448,76 mgP/m2.ngày. Kết quả nhận được cho thấy hệ thống sử dụng cây Sậy, Thủy Trúc, cỏ Vetiver và Bèo Tây có hiệu quả loại bỏ COD, TN và TP khá cao trong khi vận hành đơn giản nên có triển vọng áp dụng trong điều kiện thực tế để xử lý nước thải chăn nuôi lợn. Tuy nhiên để đánh giá tính ổn định, hệ thống cần được hoạt động với thời gian lâu dài hơn.

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