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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.
131

Síntese e caracterização de biodiesel obtido via catálises homogênea e heterogênea de óleo extraído de sementes de Helianthus annuus / Synthesis and characterization of biodiesel produced via homogeneous and heterogeneous catalysis of oil extracted from the feel of Helianthus annuus

Viviane Fernandes da Silva 29 March 2011 (has links)
O biodiesel é definido como um mono alquil éster de ácidos graxos de cadeia longa derivado de fontes renováveis tais como óleos vegetais e gorduras animais. Sua importância esta associada ao uso como um combustível alternativo para motores do ciclo Diesel podendo ser utilizado puro ou em misturas com o diesel representando economia de petróleo e menor poluição ambiental. Em geral é obtido por meio da reação de transesterificação na qual os triacilgliceróis, principais constituintes dos óleos e gorduras reagem com álcool, em presença de um catalisador ácido ou básico, produzindo ésteres de ácidos graxos e glicerol. A transesterificação pode ser conduzida por catálise homogênea ou heterogênea. O grande desafio da indústria é otimizar o processo a fim de alcançar um produto e uma rota de produção tecnologicamente eficiente e ambientalmente correta. O objetivo desta pesquisa foi estudar a síntese do biodiesel utilizando o processo de transesterificação do óleo de girassol por catálises homogênea e heterogênea. Foram realizadas reações de transesterificação via rotas metílica e etílica, empregando como catalisador homogêneo alcóxido de potássio e como catalisador heterogêneo a resina comercial de troca iônica Amberlyst 26 / Biodiesel is defined as a long-chain mono alkyl (methyl, ethyl or propyl) ester of fat acids obtained from renewable sources, like vegetable oil and animal fat. It has been used as an alternative fuel of Diesel cycle engines. It can be used blended with diesel oil or in the pure form, decreasing the use of petroleum derivates, resulting in a less environmental pollution, diminishing the green house effect. Biodiesel is obtained by transesterification reactions (alcoholysis of triglycerides with ethanol or methanol) of triacylglycerides, the main constituents of oil and fats, with alcohols and acids or alkalines catalysts. The main obtained products are the esters of fat acids and glycerol. The transesterification can be carried out under homogeneous or heterogeneous catalysis systems. The industry biggest challenge is to create a technological synthetic route that produces a pure product without causing a major environmental pollution. The aim of this work was to obtain sunflower biodiesel by transesterifications reactions carried out under homogeneous and heterogeneous catalysts. The transesterification reactions were performed by methyl and ethyl route, using as homogeneous catalysts, potassium hydroxide and as heterogeneous catalysts the ion exchange commercial resin Amberlyst 26
132

Novos tensoativos catiônicos: efeitos da estrutura do grupo hidrofílico sobre adsorção e agregação em soluções aquosas / New cationic surfactants: effects of structure of the hydrophilic group on adsorption and aggregation in aqueous solutions

Susana Shimizu 06 October 2004 (has links)
Foram sintetizadas duas séries de tensoativos catiônicos de estruturas gerais RCONH(CH2)2-N+(CH3)3 Cl- e RCONH(CH2)2-N+(CH3)2-CH2-C6H5 Cl-, sendo RCO uma cadeia acílica contendo 10, 12, 14 e 16 átomos de carbono. Estes tensoativos foram sintetizados pela reação do ácido carboxílico puro com N,N-dimetiletilenodiamina resultando na amidoamina correspondente. A quaternização desta última foi feita pela reação com cloreto de benzila ou com iodeto de metila. Os iodetos foram convertidos nos correspondentes cloretos por troca-iônica. A localização média da interface micelar e a conformação do grupo hidrofílico na micela foram investigadas por IV e RMN. A adsorção na interface solução-ar e a micelização foram estudadas por diversas técnicas: calorimetria, condutância, FEM (força eletromotriz), IV de FT, RMN e tensão superficial. Os resultados foram comparados com os de tensoativos catiônicos comuns, como R\'N+(CH3)3R\" Cl-, sendo R\' = grupo alquílico contendo de 10 a 16 carbonos e R\" = um grupo metila ou benzila. A adsorção e a micelização dos tensoativos contendo o \"espaçador\" (CONH-CH2-CH2) são mais favoráveis. Os valores de ΔGºads e ΔGºmic mais negativos para estes tensoativos, refletem principalmente a transferência mais favorável do grupo polar da solução aquosa para a interface solução/ar e/ou para a micela. Isto ocorre devido à formação de ligações de H, diretas e/ou via água, entre os grupos amida dos monômeros de tensoativo na interface e micela. As diferenças nos valores de ΔGºcabeça+CH3 dos tensoativos com e sem o grupo amida na adsorção (ΔΔGº ads cabeça+CH3 = -17.2 kJ mol-1) e micelização (ΔΔGº ads cabeça+CH3 = -5 a -7 kJ mol-1) estão de acordo com a energia de ligações de H fracas. Os resultados de IV de FT e RMN de 1H comprovaram a formação destas ligações de H e indicaram que a carbonila está presente na interface e o grupo benzila está voltado para o interior da micela. / Two series of cationic surfactants have been synthesized: benzyl-(2acylaminoetil) dimethylammonium chlorides, RCONH(CH2)2-N+(CH3)3 Cl-, and (2-acylaminoethyl)dimethylammonium chlorides, RCONH(CH2)2-N+(CH3)2-CH2-C6H5 Cl-, where RCO refers to an acyl group with 10, 12, 14 and 16 carbon atoms. These surfactants were obtained by reacting chromatographically pure carboxylic acids with N,N-dimethylethylenediamine to give an intermediate amidoamine. The latter was quaternized with benzyl chloride or methyl iodide. Surfactants with iodide counter-ion were transformed into the corresponding chlorides by ion exchange on a macro-porous resin. The average position of micellar interface and conformation of the headgroup were studied by FTIR and NMR. A multi-technique approach has been employed in order to study the effects of the presence of the \"spacer\" group (-CONH- CH2-CH2) on the adsorption and aggregation of these surfactants. The techniques employed were: calorimetry, conductance and EMF measurements, FTIR, NMR, surface tension, and Iight scattering. Surfactants with the spacer group (CONH-CH2-CH2) have more favorable Gibbs free energies of adsorption and/or micellization due to the more favorable transfer of the head-group from bulk phase to the interface and/or the micelle. This is attributed to the formation of direct, and/or water-mediated H-bonding between the surfactant amide groups. Differences in values of ΔGºHead-group+CH3 of surfactants with and without spacer group (ΔΔGº ads Head-group+CH3 = -17.2 kJ mol-1 and ΔΔGº ads Head-group+CH3 = -5 a -7 kJ mol-1 for adsorption and/or micellization, respectively) are in agreement with weak hydrogen bonding. Additional evidence for H-bond formation and for the (average) conformation of the benzyl head-group in the micelle was provided by FTIR and NMR data. The former showed that the amide group is highly hydrated, whereas the latter showed shielding/deshielding of the methylene groups of the surfactant hydrophobic tail, in agreement with a conformation in which the benzyl group is \"bent\" toward the micellar interior.
133

Avaliação da estabilidade de derivação farmacêutica hospitalar de tizanidina

Gobetti, Caren January 2017 (has links)
O cloridrato de tizanidina é um relaxante muscular esquelético de ação central, utilizado no tratamento de espasticidade. Esse fármaco é comercializado apenas sob a forma de comprimidos, o que evidencia a necessidade do desenvolvimento de formulações líquidas orais. No ambiente hospitalar, este aspecto é contornado com a preparação de suspensões derivadas, de modo a permitir a administração em crianças e em adultos com deglutição prejudicada, mas não há dados sobre sua estabilidade. O objetivo deste trabalho foi avaliar a estabilidade físico-química e microbiológica de formas farmacêuticas líquidas preparadas em ambiente hospitalar a partir da derivação de comprimidos de cloridrato de tizanidina, empregando como metodologia a cromatografia líquida de alta eficiência (CLAE) e análise microbiológica. Um método simples e indicativo de estabilidade foi desenvolvido e validado por CLAE quanto a especificidade, linearidade, limite de detecção e quantificação, precisão, exatidão e robustez. As formulações líquidas foram preparadas em triplicata e acondicionadas em frasco de polietileno tereftalato (PET) âmbar e de vidro âmbar, que foram armazenados sob três diferentes condições: em temperatura ambiente, sob refrigeração e à 40 °C. Foram coletadas amostras a cada 7 dias por um período de 56 dias para a estabilidade físico-química. As formulações líquidas foram analisadas e demonstraram ser quimicamente estáveis durante 56 dias, permitindo um período de utilização prolongado. Entretanto, a determinação da estabilidade microbiológica mostrou que estas formulações estão propensas à contaminação microbiana, o que reduziu drasticamente a sua estabilidade para 7 dias, em ambos os frascos e em todas as temperaturas avaliadas. A qualidade microbiológica foi uma questão crítica, uma vez que as formulações foram produzidas apenas em água para injetáveis e não havia conservantes presentes na formulação. Os resultados deste estudo podem servir de referência para preparar derivações de cloridrato de tizanidina em uso hospitalar, uma vez que se demonstrou a confiabilidade do intervalo de tempo de armazenamento e as condições adequadas para o uso. De acordo com os resultados deste estudo de estabilidade, este fármaco pode ser incorporado na rotina de preparo das derivações dos hospitais, atendendo a uma demanda já há tempos sinalizada. / Tizanidine hydrochloride is a centrally acting skeletal muscle relaxant, used in the manegement of spasticity. This drug is sold only as tablets, which highlights the need to develop oral liquid formulations. In the hospital environment, this aspect is circumvented by the preparation of derived suspensions, to allow administration to children and adults with impaired swallowing, but there is no data regarding their stability. The objective of this work was to evaluate the physicochemical and microbiological stability of liquid dosage forms prepared in hospital environment from tizanidine hydrochloride tablets, applying high performance liquid chromatography (HPLC) and microbiological analysis. A simple and stability-indicating HPLC method was developed and validated for specificity, linearity, limits of detection and quantification, precision, accuracy and robustness. The liquid formulations were prepared in triplicate and placed in amber PET and glass bottles, which were stored under three different conditions: at room temperature, under refrigeration and at 40 °C. Samples were collected every 7 days along 56 days for physicochemical stability. The liquid formulations were analyzed and demonstrated chemical stability for 56 days, allowing the use for long period. However, the determination of microbiological stability showed that these formulations are prone to microbial contamination, which has dramatically reduced its stability to 7 days, in both bottles and all evaluated temperatures. Microbiological quality was a critical issue, since formulations were produced only in water for injectables and there was no preservatives present in the formulation. Results of this study could be applied as a reference for tizanidine hydrochloride derived preparation in hospital, once it was demonstrated the reliability of storage time interval and proper conditions for use. According to the results of this stability study, this drug could be incorporated into the routine of hospital derivations preparation, meeting a demand already indicated.
134

Caracterização do estado sólido de ganciclovir / Solid state characterization of ganciclovir

Roque Flores, Roxana Lili 24 July 2017 (has links)
O presente trabalho teve como objetivo o estudo do estado sólido do ganciclovir (GCV) e suas diferentes formas polimórficas. O GCV é um fármaco antiviral útil no tratamento de infecções por citomegalovírus (CMV). Embora seja um fármaco amplamente usado, poucos estudos têm sido realizados sobre seu estado sólido. Atualmente, o GCV é conhecido por apresentar quatro formas cristalinas, duas anidras (Forma I e II) e duas hidratas (III e IV). Neste trabalho, nós reportamos a solução da estrutura cristalográfica da Forma I do GCV, que foi encontrado durante o screening de cristalização do fármaco, em que nove ensaios de cristalização (GCV-1, GCV-A, GCV-B, GCV-C, GCV-D, GCV-E, GCV-F, GCV-G e GCV-H) foram realizados e os materiais resultantes foram caracterizados por Difratometria de raios X (DRX), análise térmica (DTA/TG) e Hot Stage Microscopy. De todas as cristalizações realizadas foram obtidas quatro formas sólidas, denominadas como Forma I (GCV-1, GCV-B e GCV-H), Forma III (GCV-C, GCV-D, GCV-F e GCV-G), Forma IV (GCV-A) e Forma V (GCV-E). Esta última está sendo descrita pela primeira vez na literatura e indica a presença de outra forma hidratada de GCV. As Formas I, III e IV corresponderam a forma anidra e as duas formas hidratadas do fármaco, respectivamente. Além disso, foi evidenciado por experimentos de conversão de slurry e análise térmica que o cristalizado de GCV-1 (Forma I) foi o mais estável entre os materiais obtidos, e este deu origem ao monocristal da Forma I de GCV, estrutura cristalina anidra do fármaco. Neste trabalho, pela primeira vez, a estrutura cristalina deste composto foi definida por cristalografia de raios X de monocristal. A análise estrutural mostrou que a Forma I do fármaco cristaliza no grupo espacial monoclínico P21/c e está composta por quatro moléculas de GCV na sua unidade assimétrica. Cada molécula está unida intermolecularmente por ligações de hidrogênio, que dão lugar à formação de cadeias infinitas e estas por sua vez se arranjam de maneira a formar uma estrutura tridimensional. / This presented work aims to study the solid state of ganciclovir (GCV) and its different polymorphic forms. GCV is an antiviral drug useful in the treatment of cytomegalovirus (CMV) infections. Although it is a widely-used drug, few studies have been conducted on its solid state. Currently, GCV is known to have four crystalline forms, two anhydrous (Form I and II) and two hydrates (III and IV). In this investigation, we report a successful preparation of GCV Form I and its crystallographic structure, which was found during the crystallization of the drug, in which nine crystallization tests (GCV-1, GCV-A, GCV-B, GCV- D, GCV-E, GCV-F, GCV-G and GCV-H) were performed and the resulting materials were characterized by X-ray diffractometry (XRD), thermal analysis (DTA/TG) and Hot Stage Microscopy. Of all the crystallizations performed, four solid forms were obtained, denoted as Form I (GCV-1, GCV-B and GCV- H), Form III (GCV-C, GCV-D, GCV-F and GCV-G), Form IV (GCV-A) and Form V (GCV-E). The latter is being described for the first time in the literature and indicates the presence of another hydrated form of GCV. Forms I, III and IV corresponded to the anhydrous form and the two hydrated forms of the drug, respectively. In addition, it was evident by both the slurry conversion and the thermal analysis methods that the GCV-1 crystallized (Form I) was indeed the most stable amongst the materials obtained. This gave rise to GCV Form I monocrystal, anhydrous crystalline structure of the drug. The compound was characterized by monocrystal X-ray crystallography. The structural analysis showed that Form I of the drug crystallized in the monoclinic system space group P21/c is composed of four molecules of GCV in its asymmetric unit. Each molecule is linked intermolecularly by hydrogen bonds, which give rise to the formation of infinite chains arranged in a way that form a three-dimensional structure.
135

Influência do pólen sobre o desenvolvimento de colônias de abelhas africanizadas (Apis mellifera L.) / Influence of pollen on the Africanized bee colonies development (Apis mellifera L.)

Modro, Anna Frida Hatsue 18 March 2011 (has links)
O conhecimento da qualidade do pólen apícola e a sua influência sobre o desenvolvimento de colônias pode contribuir, principalmente, para a melhoria da atividade apícola e para o controle de qualidade do pólen comercializado para o consumo animal e humano. O presente trabalho objetivou caracterizar o pólen quanto a origem botânica, determinar parâmetros físicoquímicos e, relacionar com o desenvolvimento de colônias de abelhas africanizadas (Apis mellifera L.), medido pelo tamanho da área ocupada com pólen, mel e cria dentro da colméia (cm²) e a assimetria flutuante das asas de abelhas operárias. O experimento de campo foi realizado no apiário do Departamento de Entomologia e Acarologia da Escola Superior de Agricultura Luiz de Queiroz em Piracicaba, SP, onde foram instaladas cinco colméias de A. mellifera com um coletor de pólen tipo frontal. As coletas foram realizadas nas quatro estações climáticas do ano: outono (02/abr. a 28/maio/2008), inverno (09/jul. a 03/set./2008), primavera (07/out. a 02/dez./2008) e verão (09/jan. a 06/mar./2009). O local de instalação do apiário apresenta domínio de vegetação de Floresta Estacional Semidecidual (Mata Atlântica), porém com amplas áreas antropizadas, onde existem cultivos agrícolas e canteiros ornamentais com árvores e ervas. Ao longo do ano foram encontrados 81 tipos polínicos nas cargas de pólen interceptadas, pertencentes a 32 famílias botânicas. Pão de abelhas apresentou 86 tipos polínicos, pertencentes a 34 famílias botânicas, sendo Fabaceae, Asteraceae e Malvaceae as famílias com maior freqüência de tipos polínicos ( 5 tipos polínicos) e, Myrtaceae, a família com alta freqüência de grãos de pólen. As médias anuais de matéria seca (67,41%), proteína bruta (27,02%), extrato etéreo (3,66%), matéria mineral (3,34%) e carboidratos totais (65,41%) de cargas e, matéria seca (78,80%) e proteína bruta (25,89%) de pão de abelhas estão de acordo com o regulamento técnico para comercialização do pólen no Brasil. A composição polínica apresentou relação com os valores de matéria seca (Piper sp. e Vernonia polyanthes), proteína bruta (Eucalyptus sp., Fabaceae tipo 2 e Myrcia sp.), extrato etéreo (Astrocaryum sp., Parthenium sp. e V. polyanthes), matéria mineral (Myrcia sp.) e, com carboidratos totais (Parthenium sp. e V. polyanthes). Proteína bruta e extrato etéreo tenderam em se relacionar com indivíduos mais simétricos. A área ocupada dentro da colméia esteve relacionada com a quantidade de pólen coletado, riqueza e equitabilidade da composição polínica (n=45; p-valor<0,05). Com base nos resultados obtidos, conclui-se que, as famílias botânicas Fabaceae, Asteraceae, Malvaceae e Myrtaceae são as mais importantes fontes poliníferas em Piracicaba. A origem botânica do pólen apícola tem efeito sobre a sua qualidade físico-química. Os valores de proteína bruta, extrato etéreo, quantidade de pólen coletado, riqueza e equitabilidade da composição polínica influenciam positivamente o desenvolvimento de colônias. / The knowledge of the apiarist pollen and its influence on the colonies development could contribute mainly for the improvement of the apiarist activity and for the quality control of the commercialized pollen for animal and human consumption. This assignment had as a goal to characterize the pollen in respect of the botanical origin, to determine physicochemical parameters and to relate it with the africanized bee colonies development (Apis mellifera L.), measured by the area size occupied with pollen, honey and breed inside the beehive (cm²) and the wings fluctuating asymmetry from the worker bees. The outside experiment was performed in the apiary of the Entomology and Acarology Department from the Agriculture College Luiz de Queiroz in Piracicaba, SP, where there were mounted five beehives of A. mellifera with a frontal pollen collector. The swabs were done in the four year seasons: fall (02/april to 28/may/2008), winter (09/july to 03/september/2008), spring (07/october to 02/december/2008) and summer (09/january to 06/march/2009). The apiary installation place presents predominance of Semidecidual Seasonal Forest vegetation (Atlantic Forest), but with wide cultivated areas, where it exist several agricultural crops and ornamental sites with trees and herbs. During the year, there were found 81 pollinical types in the intercepted pollen load, which belong to 32 botanical families. Bees bread presented 86 pollinical types, which belong to 34 botanical families, in that Fabaceae, Asteraceae and Malvaceae are the families with higher frequency of pollinical types ( 5 pollinical types) and, Myrtaceae, the family with high frequency of pollen seeds. The annual averages of dry matter (67.41%), crude protein (27.02%), ether extract (3.66%), mineral matter (3.34%) and total carbohydrates (65.41%) of loads and, dry matter (78.80%) and crude protein (25.89%) of bees bread are in accordance with the technical regulation for pollen commercialization in Brazil. The pollinical composition presented relation with the values of dry matter (Piper sp. and Vernonia polyanthes), crude protein (Eucalyptus sp., Fabaceae type 2 and Myrcia sp.), ether extract (Astrocaryum sp., Parthenium sp. and V. polyanthes), mineral matter (Myrcia sp.) and with total carbohydrates (Parthenium sp. and V. polyanthes). Crude protein and ether extract tended to relate to individuals more symmetrical. The area occupied within the hive was related to the amount of pollen collected, richness and evenness of pollen composition (n=45; p-value<0.05). According the results, it is concluded that the Fabaceae, Asteraceae, Malvaceae and Myrtaceae botanical families are the most important polliniferous sources in Piracicaba. The botanical origin of apiarist pollen has effect on its physicochemical quality. The values of crude protein, ether extract, collected pollen quantity, richness and evenness of pollinical composition have positive influence in the colonies development.
136

Percutaneous delivery of thalidomide and its N-alkyl analogues for treatment of rheumatoid arthritis / Colleen Goosen

Goosen, Colleen January 1998 (has links)
Thesis (PhD (Pharmaceutics))--PU for CHE, 1999.
137

Impact des rejets de la ville de Niamey (Niger) sur la qualité des eaux du fleuve Niger

ALHOU, Bassirou 22 February 2007 (has links)
Résumé Ce travail est un premier pas dans l’étude de la qualité des eaux du fleuve Niger à Niamey. Il est basé sur la physico-chimie et les macroinvertébrés de cet écosystème aquatique. L’approche physico-chimique met en évidence les changements de la qualité des eaux, le long des rives, en relation avec les rejets de la ville et en fonction du régime du fleuve. L’impact de ces rejets est très négligeable à l’échelle de l’écosystème à cause de la forte dilution. La demande chimique en oxygène, l’oxygène dissous, l’ammonium, les orthophosphates et le phosphore total sont les principaux facteurs environnementaux qui déterminent la pollution des eaux liée aux matières organiques et oxydables, aux matières azotées et phosphorées dans ce fleuve. L’étude des macroinvertébrés fait ressortir 83 taxons répartis le long du fleuve Niger à Niamey. La description des peuplements de macroinvertébrés montre une variation de structure des communautés, en passant de l’amont à l’aval des points de rejets, caractérisée par une baisse de la richesse et de la diversité taxonomique en aval immédiat des rejets. La présence, dans certaines stations en aval immédiat des rejets, des taxons tels que Chironomus gr. plumosus, Melania sp., les familles des Syrphidae et des Culicidae, est une indication de la dégradation de la qualité des eaux liée à la matière organique. Par contre, les taxons comme Thraulus sp., Elassoneuria sp., Afronurus sp., Centroptiloides sp., Adenophlebia sp., Dipseudopsis sp. et Neoperla sp., appartenant aux Ephéméroptères, Trichoptères et Plécoptères, reflètent une meilleure qualité de l’eau dans les stations de référence situées en amont de tous les points de rejets. L’importante diversité de la famille des Chironomidae (20 taxons) dans ce cours d’eau offre de bonnes perspectives pour son utilisation dans l’étude de la qualité des eaux du fleuve Niger à Niamey. Les descripteurs qui expliquent significativement la distribution des communautés de macroinvertébrés le long du fleuve Niger à Niamey sont la matière organique (demande chimique en oxygène) et les nutriments (ammonium, orthophosphates et phosphore total). La technique d’échantillonnage au filet troubleau explique beaucoup plus d’inertie que les substrats artificiels. Quant à la jacinthe d’eau, elle présente peu d’intérêt dans l’étude de la qualité des eaux du fleuve Niger à Niamey à cause de sa présence uniquement en période de crue. Summary This survey is a first step in the study of water quality of the River Niger in Niamey. It is based on physicochemical factors and the macroinvertebrates inhabiting this aquatic ecosystem. The physicochemical approach underlines the changes in water quality, along the banks, in relation with wastewater from the city of Niamey, and as a response to seasonal variations of water level. The impact of wastewater on the scale of the entire ecosystem appears very limited, because of the strong dilution. Chemical oxygen demand, dissolved oxygen, ammonium, phosphates and total phosphorus levels are the main environmental factors that determine both the pollution due to organic (and oxidizable) matter, and the pollution resulting from nitrogen and phosphorus-based chemicals in this river. In this survey 83 taxa of macroinvertebrates were found along the River Niger in Niamey. The description of macroinvertebrates shows a variation of community structure, from upstream to downstream, that is characterized by a decrease of taxonomic richness and diversity downstream wastewater discharges. The presence of Chironomus gr. plumosus, Melania sp., families of Syrphidae and Culicidae indicates a deterioration of water quality due to organic matter in some stations near wastewater discharges. However, taxa like Thraulus sp., Elassoneuria sp., Afronurus sp., Centroptiloides sp., Adenophlebia sp., Dipseudopsis sp. and Neoperla sp. reflect a better quality of water in the reference stations located upstream of all wastewater discharges. The high diversity of Chironomidae (20 taxa) in this river makes them a good candidate taxonomic group to be used for the assessment of water quality in the River Niger near Niamey. The factors which significantly explain the distribution of macroinvertebrates communities along the River Niger in Niamey are organic matter (chemical oxygen demand) and nutrients (ammonium, phosphates, total phosphorus). Results from net hand samples explain a higher fraction of total inertia than the ones obtained using artificial substrata. Water hyacinths play a limited role in the survey of water quality in the Niger near Niamey, because they are only present during floodperiods.
138

Influences of Firework Displays on Ambient Air Quality during the Lantern Festival in Kaohsiung City

Chien, Li-hsing 10 August 2010 (has links)
In recent years, the celebration activities of various types of folk-custom festivals in Taiwan have already been getting more and more attention from civilians. Festivities throughout the whole island are traditionally accompanied by loud and brightly colored firework displays. Among these activities, the firework display during the Chinese Lantern Festival in Kaohsiung City is one of the largest festivals in Taiwan every year. Therefore, it is important to investigate the influences of firework displays on ambient air quality during the Chinese Lantern Festival in Kaohsiung City. Field measurement of ambient gaseous pollutants and particulate matter (PM) was conducted on February 9-12, 2009, the Chinese Lantern Festival, in Kaohsiung City. Moreover, three kinds of firework powders obtained from the same factory producing Kaohsiung Lantern Festival fireworks were burned in a combustion chamber to determine the physicochemical properties of firework aerosols. Metallic elements were analyzed with an inductively coupled plasma-atomic emission spectrometer (ICP-AES). Ionic species and carbonaceous contents in the PM samples were analyzed with an ion chromatography (IC) and an elemental analyzer (EA), respectively. Finally, the source identification and apportionment of PM were analyzed by principal component analysis (PCA), enrichment factor (EF), and receptor modeling (CMB). For inorganic gaseous pollutants, the concentration peaks of NO, NO2, O3, CO were observed during the firework periods, and the concentration peak of NO was approximately 8.8 times higher than those during the non-firework periods. This study further revealed that, even at nighttime, ambient O3 could be reduced dramatically during the firework periods, whenas NO2 concentration increased concurrently, due to titration effects resulting from the prompt reaction of NO with O3 to form NO2 and O2. For organic gaseous pollutants, the concentration peak of toluene during the firework periods was approximately 2.2-4.1 times higher than those during the non-firework periods. Several metallic elements of PM during the firework display periods were obviously higher than those during the non-firework periods. On February 10, the concentrations of Mg, K, Pb, and Sr in PM2.5 were 10 times higher than those during the non-firework periods. Besides, the Cl-/Na+ ratio was slightly smaller than 1 in Kaohsiung Harbor, but it was approximately 3 during the firework display periods since Cl- came form chlorine content in firework aerosols at this time. Moreover, OC/EC ratio increased up to 2.8. In addition to the analysis of gaseous pollutants and PM during the Chinese Lantern Festival in Kaohsiung City, this study burned firework powders in a self-designed combustion chamber to measure the physicochemical properties of firework aerosols. In the results, K, Mg, Cl-, OC were major contents (<10%) in the aerosols produced from the burning firework powders. Moreover, Cl-/Na+ and OC/EC ratio were 15.0~23.4 and 2.9~3.2, respectively. Consequently, Cl-/Na+ and OC/EC ratio can be used as two important indicators of firework displays. Results obtained from PCA and CMB receptor modeling showed that the major sources of aerosols during the firework display periods were firework displays, motor/diesel vehicle exhanst, soil dusts, and marine aerosols. Besides, the firework displays on February 10 contributed approximately 25.2% and 16.6% of PM10 at two sampling sites, respectively.
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Influences of Sea-land Breezes and Northeastern Monsoon on the Transportation and Dispersion of Air Pollutants over Coastal Region in Southern Taiwan

Tsai, Hsieh-Hung 11 August 2010 (has links)
This study investigated the influences of sea-land breezes (SLBs) and northeastern monsoon (NEM) on the transportation and dispersion of air pollutants over coastal region in southern Taiwan. The physicochemical properties of particulate matter (PM) was simultaneously sampled and analyzed at both inland and offshore sites during eight intensive sampling periods. This study further used a SURFER 2-D plotting software, a backward trajectory model, a 3-D meteorological model (MM5), and a comprehensive air quality model (CAMx) to simulate surface wind fields and spatial distribution of air pollutants over the coastal region during the intensive sampling periods of SLBs and NEM. According to the meteorological condition and the synoptic weather patterns of the observation data showed that the SLBs sampling periods commonly occurred the weather patterns were zone of low pressure, pacific high pressure, and west stretch of the pacific high pressure when the main prevailing wind direction were west wind and southwest wind. During the NEM sampling periods, the weather patterns were strong northeastern monsoon, standard northeastern monsoon, and outflow rebound with high pressure in southern Taiwan, and then the main prevailing wind direction were northwest wind and northeast wind. However, during the MIX sampling periods, the weather patterns were outflow circulation of typhoon, weak northeastern monsoon, and outflow rebound with high pressure, while the wind directions didn¡¦t change regular. Thus, at coastal sites, the sea-land breezes induce an inland transport of air pollutants during the daytime and a seaward return of air pollutants at nighttime, causing a recirculation of air pollutants back to inland regions each day during the SLBs sampling periods. During the NEM sampling period was mainly brought from the northeastern wind which transported air pollutants from the northern region to Kaohsiung metropolitan area. The results of PM concentration and size distribution indicated that the inland sites had a higher fraction of fine particles (PM2.5), whereas the offshore sites had a higher fraction of coarse particles (PM2.5-10). These phenomena were attributed to the fact that marine aerosols are generally abundant in the coarse particles. PM concentration is relatively higher during the NEM sampling periods than during the SLBs and MIX sampling periods. For PM concentration, the order of secondary inorganic aerosols (SIA) was NEM > MIX > SLBs, while the SIA/Ions ratio of PM2.5 were approximately 50% during sampling periods. The [NO3-]/[SO42-] ratios of PM2.5 and PM2.5-10 during the SLBs sampling periods were always lowest than those during the NEM and MIX sampling periods. It is suggested that the PM concentrations during the SLBs sampling periods were highly influenced by stationary sources emissions. The crustal elements indicated that the Al, Ca, Fe, and K contributed major composition of particles. Artificial metals, such as Mg, Pb, V, and Zn were also enriched in the atmospheric PM during the NEM sampling periods. In addition, the higher concentration of Fe was attributed to local anthropogenic emission and weak northeastern monsoon during the MIX sampling periods. Regardless of inland or offshore sites, a high concentration of secondary organic carbon (SOC) during the NEM and MIX sampling periods was consistent with OC/EC ratio higher than 2.2 indicates the potential formation of secondary aerosols. Chloride deficit of PM at inland sites were lost easily for approximately 40.28% during the NEM sampling periods. Moreover, the lowest [Cl-]/[Na+] ratio occurred during the sampling periods when the chloride deficit was relative high at inland sites. According to the results of neutralization ratio (NR), regardless of the periods (SLBs, NEM, and MIX), the particulates of inland and offshore sites were both acid. During the NEM and MIX sampling periods, sulphur oxidation ratio (SOR) of PM2.5 over coastal region in southern Taiwan were above 0.25. It is suggested that the results of SOR during those sampling periods were highly influenced by long transportation. In addition, the nitrogen oxidation ratio was lower influenced than SOR over coastal region in southern Taiwan. It is suggested that air quality of Kaohsiung metropolitan area were influenced by the industrial source emissions. During the SLBs sampling period, sea breezes blown in the morning transported the offshore PM10 back to the inland sites in the Kaohsiung metropolitan area. In contrast, the air mass observed during the NEM sampling period was brought to the Kaohsiung metropolitan area mainly by a northerly wind which transported air mass originating in the northern region (i.e. Chiayi counties). The backward trajectory modeling of the MIX sampling periods suggested that the winds were dominated by the Northeastern Monsoon, and as such, likely inhibited the influences of sea-land breezes. Local surface air mass circulation over southern Taiwan obtained from MM5 model influenced by the southwestern monsoon during the SLBs sampling period. The weather in southern Taiwan during the NEM intensive sampling period was occasionally influenced by the Northeastern Monsoon as well as by complex terrain. During the MIX sampling periods, air mass recirculation was frequently observed in the coastal region of southern Taiwan. The results of CAMx model showed that air pollutions were occurred apparent sea breezes in the afternoon and land breezes at night during the SLBs sampling period. During the NEM sampling period, a strong Northeastern Monsoon blew air pollutions from the north to the southern region. We have compared the model simulation with field measured O3 and PM10 concentrations for inland and offshore regions. The order of correlation coefficients of &not;the model simulation and the measurement for O3&not; and PM10 in sampling periods is SLBs>MIX>NEM and NEM>MIX>SLBs, respectively. Overall, the correlation coefficients of the model simulation and the measurement were middle and high correlation.
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Diurnal Variation of Atmospheric Particles and their Source Fingerprint at Xiamen Bay

Wu, Chung-Yi 31 August 2011 (has links)
In recent years, the rapid development of economy and industry in Xiamen Bay causes serious environmental problems, particularly poor air quality and visibility impairment. There are no large-scale industrial emission sources in Kinmen Island, however, its ambient air quality is always the poorest in Taiwan. Moreover, ambient air quality monitoring data showed that PM10 concentrations varied in daytime and at nighttime. Consequently, this study tired to ascertain the potential causes for this phenomenon. This study selected ten particulate matter (PM) sampling sites at Xiamen Bay, including five sites at Kinmen Island and five sites at metro Xiamen. Particulate matter sampling was conducted in daytime (8:00-17:00) and at nighttime (17:00-8:00), which included regular and intensive sampling. Regular sampling was conducted to collect PM10 with high-volume samplers three times a month from April 2009 to April 2010, while intensive sampling was conducted to collect fine (PM2.5) and coarse (PM2.5-10) particles with dichotomous samplers and particle size distribution with a MOUDI at site B2 for consecutive 5 days in the spring and winter of 2009~2010. After sampling, the physicochemical properties of PM, including mass concentrations, particle size distribution, water- soluble ionic species, metallic elements, and carbonaceous contents were further analyzed. The level of atmospheric PM is affected by meteorological condition, thus PM10 concentrations in winter and fall was much higher than those in spring and summer. Results from backward trajectories showed that the concentrations of PM10 blown from the north were generally higher than those from the south. Furthermore, t-test analysis indicated that PM10 concentrations in daytime and at nighttime at site B3 were significantly different (p-value<0.05). During the intensive sampling periods, PM10 concentrations were mainly affected by coarse particles compared to fine particles. The highest concentration for fine and coarse particle modes occurred at the size ranges of 0.32~0.56 £gm and 3.2~5.6 £gm, respectively. The most abundant water-soluble ionic species of PM10 were secondary inorganic aerosols (SO42-, NO3-, and NH4+) which accounted for 85% of total ions. The daytime and nighttime PM10 concentration ratios (D/N) for Mg, K, Ca, Cr, Mn, Fe, Zn, Al, Cu, As, and V were in the same order of magnitude, however, the D/N ratios of Cd, Pb, Ni, and Ti in spring and summer varied higher than an order of magnitude, indicating that the emission sources of PM were different in daytime and at nighttime. Correlation analysis of OC and EC showed that OC and EC at nighttime had a higher correlation than those in daytime, while OC and EC had a higher correlation in Kinmen Island than those in metro Xiamen, indicating carbonaceous sources must be different in summer and winter at Xiamen Bay. Enrichment factor analysis revealed that ceramic industry, stone processing, and cement industry had higher correlation with PM10 concentration than utility power plants. Crustal dusts consisted of road dusts, farmland dusts, and constructive dusts, while biomass burning was not a negligible sources. Results obtained from PCA and CMB receptor modeling showed that major sources of PM in Xiamen Bay were secondary inorganic aerosols, fuel and biomass burning, marine aerosols, vehicular exhansts, and soil dusts. Besides, stone processing, cement industry, ceramic industry, and utility power plants had the highest contribution in winter. Their contributions in daytime and at nighttime were 38% and 45%, respectively.

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