Syftet med arbetet är att undersöka svängrelaterade aspekter i fyra olika spelsituationer i tre olika konstellationer där jag själv medverkat som basist. De fyra spelsituationerna är ett jam, en studioinspelning, ett rep inför konsert och en konsert. I arbetsprocessen beskriver jag min roll som jazzbasist och mitt förhållande till de andra musikerna när jag upplever att musiken svänger, respektive inte svänger. Jag har i arbetet ställt mig frågan: Vilken betydelse har soundet för svänget?    Jag har intervjuat tre personer, verksamma inom olika musikaliska områden; en dirigent, en jazztrumpetare, tillika storbandsledare, samt en jazzpianist, i huvudsak verksam inom frijazzen. Intervjufrågorna har kretsat kring hur personerna i fråga ser på svängbegreppet och vilken roll soundet har i förhållande till detta.   Efter mitt kandidatarbete fick jag en fråga om det var möjligt att ”mäta” svänget i musik. Jag har därför gjort ett mätningsförsök på en av de inspelade låtarna från studion där jag jämfört tidsförhållandet mellan trummornas ridecymbal och basens fjärdedelar i walkingen.   Jag har under arbetets gång analyserat inspelningarna och tittat närmare på sådant som jag bedömt höra till svängrelaterade aspekter. Parallellt med detta har jag knutit an till intervjusvaren, vilka visat många viktiga samband. I arbetet har jag undersökt samtliga beståndsdelar och begrepp i inspelningarna: sound, time, harmonik, rytmiska underdelningar samt tension and release. Jag kan efter studien konstatera att sväng är något högst subjektivt som ständigt varierar beroende på situation. Varje ny idé som vibrerar tillsammans med något annat skapar sitt unika sväng.   Jag har funnit i studien att jag spelade walkingen annorlunda i förhållande till musikens händelseförlopp, vilket intresserat mig att fördjupa mig i. Att frasera fjärdedelarna kortare eller längre utgör beroende på vad jag spelar detta mot på var sitt sätt ett driv, vilket påverkar svänget. Att spela akustiskt, respektive elektroniskt förstärkt i varierande akustiska miljöer påverkar soundet som i sin tur spelar en stor roll för svänget. Anpassningen som sker i basspelet i förhållande till soundet blev i denna studie ett nytt område att utforska.

Magister Pharmaceuticae - MPharm / Sutherlandia frutescens is a traditional plant medicine widely used in South Africa. Traditionally, the leaves of S. frutescens are mainly used as a tea, but these traditional dosage forms have several disadvantages, including that they are not particularly convenient to prepare and store, encourage dosage inaccuracy and are highly susceptible to microbial contamination. To solve these problems, dried aqueous extract forms, e.g. freeze dried aqueous extract (FDAE) of S. frutescens were prepared, but they, in turn, may still suffer from instability and contain mainly hydrophilic phytoconstituents that are poorly absorbed and delivered for in vivo activity. Modified forms of the FDAE, i.e. the active phytopharmaceutical ingredient (API), may be a better solution. Therefore this study sought to prepare liposomes and phytosomes of the freeze dried aqueous extract of Sutherlandia frutescens, as a means of increasing the total the surface area of the API, thus improving its release and dissolution in gastrointestinal fluids. Liposomes and phytosomes of the FDAE of Sutherlandia frutescens obtained were prepared using a thin film hydration method at ratios of lecithin: S. frutescens (3:1) and phosphatidylcholine: S. frutescens (2:1) respectively. The physical characteristics (i.e. particle size, size distribution, zeta potential, and morphology), of flavonoid glycosides (i.e. sutherlandins A to D; API) as well as content and release profiles of each dosage form (i.e. FDAE liposome or phytosomes) at pH 1.2 and pH 6.8 was determined. A validated HPLC assay was used to determine and compare the flavonoid glycoside content and release profiles of the liposomes and phytosomes. Both liposomes and phytosomes were successfully prepared, in moderate yields (± 30 %, and ± 50 %, respectively), using the thin film hydration method. The liposomes had a significantly smaller size, lower size distribution, higher zeta potential and better stability than the phytosomes (p < 0.05). The phytosomes, however, had significantly higher flavonoid glycoside encapsulation efficiency than the liposomes (±50 % vs ±26 %; p < 0.01). In addition, the release at 120 minutes, of flavonoid glycosides from the liposomes (63%, 58%, 76% and 46% % at pH 1.2, and 78%, 76%, 87% and 89 % at pH 6.8 for sutherlandins A, B, C and D, respectively) was significantly higher and faster than that of the phytosomes (52%, 41%, 51% and 39 % at pH 1.2, and 31% 31%, 33%and 45% % at pH 6.8, for sutherlandins A, B, C and D, respectively). The differences in release were likely due to differences in particle size and size distribution of the two modified API forms. Overall, liposomes and phytosomes can be considered promising vehicles for delayed delivery of herbal crude extracts. Based on its characteristics (i.e. narrower size distribution, and better stability), the liposomes were preferred compared to the phytosomes offering a better kinetic release profile. The phytosomes had higher encapsulation than the liposomes that may be due to complex formation between the API and the lipid.

Mini-matrix multiple unit dosage forms (MUDFs) of diclofenac sodium and S(+) ibuprofen have been prepared. Normal tabletting techniques were used to form the mini-matrices prior to their enclosure in hard gelatin capsules. Four natural hydrophilic gums, namely xanthan, karaya, locust bean and carrageenan gums as well as hydroxypropyl methylcellulose (HPMC) were used as the principle release-retarding agents. Various excipients - lactose, Encompress®, cellulose acetate phthalate (CAP), Veegum F® and Avicel PH101® - were added in different proportions to further modify drug release. The diclofenac sodium mini-matrices (4.5 mm in diameter) were produced by the wet granulation method. The release profiles from several encapsulated minimatrices in phosphate buffer solution (pH 7.0) showed that xanthan, karaya and locust bean gums could sustain the release of diclofenac sodium while the carrageenan gum did not produce a satisfactory sustaining effect. The rank order of decreasing swelling rate in both axial and radial dimensions was xanthan > karaya > locust bean gum and each of these gums showed almost Fickian swelling behaviour. The solvent penetration rates were consistent with the swelling rates. However, the order of decreasing drug release and erosion rates was locust bean> xanthan > karaya gum. For each of these gums, the release behaviour was anomalous indicating that both Fickian drug diffusion and polymer relaxation were involved in the release process. The dominant mechanism depended on the nature and content of the gum, as well as the stage in the dissolution period. The study involving xanthan gum showed that the diclofenac sodium release rate declined linearly with a progressive increase in the gumcontent, without changing the release behaviour. However, for high drug: xanthan gum ratio (2:1), the release kinetics changed to Super Case II. Solubility differences between the excipients did not affect the release rate, but increasing proportions of each excipient produced a faster release rate with the release mechanism changing from anomalous to Case II and then to Super Case II transport. Mini-matrices containing HPMC produced faster drug release than those containing the three natural gums. There was no synergistic effect between xanthan and locust bean gums on the release of diclofenac sodium from mini-matrices. Variation in the stirring speed (used in the dissolution apparatus) and matrix volume had little effect on drug release, whereas the pH of the dissolution medium greatly affected the release of diclofenac sodium. Following on from the studies involving diclofenac sodium, xanthan and karaya gums were used to produce mini-matrices of S(+) ibuprofen. Excipients with good compressibility characteristics such as lactose, Encompress® and Avicel PH101® were needed in the formulations. At pH 7, higher drug release rates were obtained with karaya gum (Super Case II mechanism) compared with xanthan gum (anomalous behaviour). Solubility differences between the excipients slightly affected the release rate. Compression forces (11 - 26 kN) slightly affected the crushing strength. The minimatrices were relatively stable to variation in temperature (5 - 37°C) and relative humidity (10 - 75%) over a 2 month time period. These studies have shown that near zero-order release of diclofenac sodium and S(+) ibuprofen can be achieved using encapsulated mini-matrices formulations. The release mechanisms and release rates can be adjusted by variation of the type and content of gums and/or excipients.

Sasol biological sludge, coal fine and gasification ash were the three waste streams involved in this study. The main concern is that on their own they are not suitable as growth mediums, the ash is alkaline (pH>12) with high salinity (total dissolved solids of 8000 mg ℓ-1). Fine ash is microporous (particle size diameter <250 μm) and forms cemented layers that can restrict root growth while, gasification ash in macroporous (most particle size diameter ranged between 1 and 75 mm) and has a low water holding capacity. Sludge is unstable and can inhibit gaseous exchange. However, these wastes potentially, have physical, biological and chemical attributes that make them suitable as hospitable growth medium. Sludge can promote micro-fauna activity and, provide plant available nitrogen (N) as well as phosphorus (P) the ash is poor in. On a short term bases and in the long term it can also contribute to cation exchange capacity (CEC). Fine ash can increase water holding capacity and gasification ash can improve gaseous exchange. It was hypothesized that if the ash was treated with sludge, pH will be reduced to between 5.5 and 8, and weathering will reduce salinity to less than 400 mSm-1, increase CEC and increase plant available N and P. Therefore, the main purpose of this laboratory column study was to establish combinations of these waste streams that hold promise as plant growth media, based on various chemical and physical criteria link to hospitable plant growth media, as well as the influence of weathering on the release of essential plant nutrients. A total of 51 mixtures (each weighing 2.6 kg) were formulated based on wet mass basis and divided into 6 groups based on sludge content (0, 10, 20, 30, 40 and 50%) and packed into columns, subjected to wetting and drying for 1 year (10 wetting and drying cycles) by passing through deionized water equivalent to the pore volume and allowing the mixtures to dry in between. The leachates were analysed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Kjeldahl procedures (for N release). Total elemental analysis was done using X-ray Fluorescence Spectroscopy (XRF) and acid digestion method. Particle size distribution was done using the sieve method. Cation exchange properties were assessed using ammonium acetate (NH4OAc), lithium chloride (LiCl) and potassium chloride (KCl) methods. Results indicated that sludge was critical for these mixtures,at a minimal content of 10% it increased the water holding capacity of the mixtures. In the mineralization of inorganic N at a lower limit of 20% sludgeenabled the production of plant available NH4+ and NO3- and less NO2-. Increasing sludge to 50% further reduced the production of NO2- in the mixtures. In terms of elemental release, mixtures without sludge were dominated by Na and the order of abundance was as follows; Na>K>Ca>Mg>P on mmol kg-1 but the introduction of sludge at a lower content limit of 10% changed the abundance of the elements as follows; P>Mg>Ca>Na>K on mmol kg-1. Sludge content as low as 10% reduced the pH of the mixtures to between 7.6 and 8 and EC to less than 400 mSm-1. However, increasing sludge to 50% increased the leachate EC dramatically and kept the EC high (415 mSm-1) till the end. Introduction of sludge at a low limit of 10 % content increased the CEC above 8 cmolc kg-1. The effects of fine ash on the water holding capacity of the mixtures were seen at the 10 % level, for example, mixture 13 with 10% fine ash had 0.3 mg kg-1, while mixture 12 with 0% fine ash had 0.27 mg kg-1. Increasing fine ash content above 40% increased pozzalanic properties, pH (>8), EC (>400 mSm-1), Na release and reduced CEC.Gasification ash is the biggest waste stream and utilizing these wastes as growth media will mean that it realistically will always dominate these mixtures. This study showed that on its own it will be a challenging environment. However, the amendent with sludge and fine ash resulted in some chemically and physically favourable changes in these media. It can be concluded that the main objective has been achieved and bio assay evalution of theses mixtures is recommended Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Plant Production and Soil Science / unrestricted

A capacidade de dispersão e parasitismo de D. longicaudata, proveniente de larvas de Ceratitis capitata (linhagem Ceratitis) e de Anastrepha fraterculus (linhagem Anastrepha) foi avaliada após liberação em pomar de goiaba. Onze liberações de cerca de 3.000 parasitoides foram realizadas entre março de 2014 e abril de 2015 no centro de um talhão de 15 ha de goiaba localizado no Projeto de Irrigação do Jaíba (15°14\'03.7\"S 43°56\'54.0\"W), em Jaíba, MG, Brasil. A dispersão foi monitorada, a partir de um ponto central de liberação, nas direções cardeais e colaterais, a uma distância de 6 m até 272 m, distantes 12 m entre si nas direções cardeais e 17 m nas colaterais. Em cada ponto uma \"unidade de parasitismo\", ou seja, um sache com cerca de 20 larvas de terceiro instar do hospedeiro mais dieta envoltos em tecido voile, foi pendurada. Larvas de C. capitata e de A. fraterculus foram oferecidas para recuperar os parasitoides em cinco liberações onde os parasitoides não tiveram escolha pelo hospedeiro e outras seis onde tiveram escolha. As \"unidades de parasitismo\" permaneceram 24 h no pomar quando foram substituídas por novas, também retiradas após 24h. Após sete e 15 dias novas \"unidades de parasitismo\" foram distribuídas e mantidas por 24 h. Foram verificadas a porcentagem de parasitismo, razão sexual, mortalidade das larvas hospedeiras e a direção de dispersão. Os dados foram analisados utilizando modelos lineares generalizados de efeito misto através do sistema estatístico R. A distância média de dispersão (DM) e a área de dispersão (S²) de D. longicaudata foram determinadas utilizando-se o modelo proposto por Dobzhansky e Wright. O total de 10.351 parasitoides foi recuperado, todos pertencentes à espécie D. longicaudata, 769 provenientes do hospedeiro A. fraterculus e 9.582 de C. capitata. A mortalidade das larvas foi maior para o hospedeiro A. fraterculus. A razão sexual foi preferencialmente (ou tendeu) para machos e diferiu apenas entre os hospedeiros, sendo maior em parasitoides recuperados de A. fraterculus (0,34), independente da linhagem liberada. Nenhuma variável climática analisada influenciou o parasitismo ou a mortalidade das larvas. A linhagem Ceratitis foi a que mais se dispersou e parasitou larvas até a distância máxima de 173 m e atingiu uma área de dispersão de até 34.067,17m². As duas linhagens do parasitoide se dispersaram em todas as direções, mas demonstraram uma tendência a se dispersar para a direção leste. As duas linhagens foram capazes de sobreviver e parasitar larvas de A. fraterculus e C. capitata por até 15 dias após sua liberação, mas, número maior de exemplares da linhagem Anastrepha foi recuperado após 15 dias parasitando larvas dos dois hospedeiros. A linhagem Anastrepha proporcionou os mais altos índices de parasitismo nas maiores distâncias do ponto de liberação e a linhagem Ceratitis em pontos mais próximos. Com base na maior capacidade de sobrevivência em condição de semiárido, maior capacidade de parasitismo em distâncias maiores do ponto de liberação e na área de dispersão média obtida (27.368,24 m²) recomenda-se a liberação de 3.000 parasitoides da linhagem Anastrepha a cada 2,7 ha de goiaba / The ability of dispersal and parasitism of Diachasmimorpha longicaudata reared with the larval host of Ceratitis capitata (Ceratitis strain) and Anastrepha fraterculus (Anastrepha strain) was evaluated in a guava orchard. Eleven releases of approximately 3,000 parasitoids were conducted between March 2014 and April 2015 at the center of a 15-ha guava orchard located in the Jaíba Irrigation Project area (15°14?03.7?S, 43°56?54.0?W) in Jaíba, State of Minas Gerais, Brazil. The dispersal of Diachasmimorpha longicaudata was monitored within a distance of 6 m to 272 m from a central point of release to the cardinal and collateral directions; each cardinal and collateral direction point was located at a distance of 12 m and 17 m from each other, respectively. At each point, a \"parasitism unit\", that comprised a sachet made of voile fabric containing 20 third instar larval host more diet was hung. Larvae of C. capitata and A. fraterculus were offered to recover the parasitoids into five releases where the parasitoids had no choice by the host and six where they had choice. The \"parasitism units\" remained for 24 hours in the orchard when they were replaced with new ones, also remained for 24 hours. After 7 and 15 days others \"parasitism units\" were distributed and maintained for 24 h. Observations on parasitism, sex ratio, mortality of host larvae, and the direction of dispersal were made for each time point. Data were analyzed using the general linear models and mixed effect models by the R statistical system. The average distance dispersion (DM) and the dispersion area (S²) of D. longicaudata were determined using the model proposed by Dobzhansky and Wright. A total of 10,351 parasitoids was recovered, all belonging to D. longicaudata, 769 from the host A. fraterculus and 9,582 from C. capitata. Larval mortality was higher in A. fraterculus. The sex ratio showed a tendency for males and differed between the hosts; the number of males was higher in the parasitoids recovered from A. fraterculus (0.34), regardless of the strain of D. longicaudata released. Parasitism or larval mortality was not influenced by any of the climatic variables analyzed. The Ceratitis strain was most dispersed and parasitized larvae up to a maximum distance of 173 m and scattering area of up to 34,067.17 m². Both parasitoid strains scattered in all directions, but showed a tendency to disperse toward the east. The two strains were able to survive and parasitize the larvae of A. fraterculus and C. capitata for up to 15 days after its release, but more number of the Anastrepha strain were recovered after 15 days of parasitizing the larvae of the two hosts. The Anastrepha strain showed the highest parasitism rate over larger distances from the point of release, while the Ceratitis strain parasitized the larval hosts close to the release points. Based on the highest survival in semiarid conditions, the higher parasitism capacity at greater distances from the point of release, and the average obtained dispersion area (27,368.24 m²), we recommend the release of 3,000 parasitoids of Anastrepha strain in every 2.7 ha of guava orchards

archives@tulane.edu / 1 / Olakunle Francis Ojo

Repellents play a key role in preventing mosquito-borne diseases such as malaria by reducing human-vector contact. The general mechanism of action relies on providing a repelling vapour around the applied area on the skin. Thus, the proper evaporation rate and consistency of the composition of the released vapour are factors determining the performance of repellent formulations. The formulation should evaporate fast enough to provide a sufficient level of repellence during its life time. However, if evaporation proceeds too fast, then it will be depleted rapidly so that activity is lost within a short period of time, which makes the repellent inefficient. Several controlled-release approaches have been developed to improve both the protection time and level. However, these techniques have inherent drawbacks from the industrial point of view. Moreover, these techniques mostly focus only on reducing the release rate, while the consistency of the vapour composition has not been addressed. In the present study, a novel approach towards controlling the evaporation behaviour of repellents is proposed. It is based on engineering the molecular interactions in order to design negative pseudo-azeotrope formulations. Negative pseudo-azeotrope mixtures are less volatile than the pure parent components and they do not undergo separation during evaporation. The feasibility of the idea was investigated by studying the molecular structure of generally available repellents. Among known molecular interactions, hydrogen bonding has the most likely impact on the formation of azeotropes and in particular pseudo-azeotropes. Thus, established repellents were classified based on their chemical structures and their capability to take part in hydrogen bonding. Next, a simple spectroscopic method for anticipating pseudoazeotropes formation was developed. Binary compositions of nonanoic acid and ethyl butylacetylaminopropionate (IR3535) showed a potential for forming pseudo-azeotrope mixtures. Hence R3535 and nonanoic acid were selected as model compounds to test the hypothesis. An experimental technique to confirm pseudo-azeotrope formation and to locate the composition of the probable pseudo-azeotrope point was required. To this end, an oven test was designed. The temporal mass loss, under an isothermal program, of a series of evaporating mixtures was measured. Simultaneously, the Fourier transform infrared (FTIR) spectra of the liquid remaining was recorded. Inverse analysis techniques were used to determine the composition of remaining liquid mixtures from the recorded FTIR spectra. The oven tests revealed that, as vaporisation progressed, the composition of the liquid remaining and the emitted vapour converged to a fixed IR3535 content of ca. 75 mol%. Mixtures close to this composition also featured the lowest volatility. Oven test also showed that the composition of the liquid mixtures diverged from the fixed IR3535 content of ca. 10 mol%. Mixtures close to this composition featured the highest volatility. These observations showed that IR3535 and nonanoic acid forms two pseudo-azeotrope compositions, i.e. a negative pseudo-azeotrope at an IR3535 content of ca. 75 mol%, and a positive pseudo-azeotrope at IR3535 content of ca. 10 mol%. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied to check these results. TGA confirmed that the negative pseudo-azeotrope mixture is less volatile while the positive pseudo-azeotrope is more volatile than the parent compounds. The DSC results revealed that in comparison with the pure compounds, negative pseudo-azeotrope had a lower boiling point onset while the positive pseudo-azeotrope had a higher boiling point. Although negative pseudo-azeotrope repellent formulations have the desired lower constant release rate, their repellent activity needed to be tested. This is due to the fact that mixing the ingredients to formulate a negative pseudo-azeotrope results in interactions among the components. As a consequence, the inherent repellence effect of the compounds might have been impaired in the mixture. The modified arm-in-cage test was used to test the repellence of the controlled-release repellent formulation i.e. the negative pseudo-azeotrope of the IR3535 + nonanoic acid system. Results showed that the mixture featured improved performance with respect to both repellence efficacy and persistence. Moreover, the negative pseudo-azeotrope also exhibited a knock down effect, even resulting in mortality of most of the test mosquitoes. The presence of two pseudo-azeotrope points at different composition in the IR3535 + nonanoic acid system is a rare occurrence, analogous to double azeotropy. Thus, molecular simulation techniques were used to explore the nature of system and the interactions responsible for this unique behaviour. Gibbs-Monte Carlo simulation results suggest that variations in the sizes of the molecular clusters present in the liquid at various compositions might be responsible. They revealed that IR3535 and nonanoic acid in neat form are both highly structured liquids. The break-down in the structure of IR3535 at high concentrations of the acid may be the origin of increased evaporation rate and formation of the positive pseudo-azeotrope. On the other hand, negative pseudo-azeotrope may be resulted from formation of bulkier clusters at the ration of 3:1 (IR3535: nonanoic acid). / Thesis (PhD (Chemical Technology))--University of Pretoria, 2016. / English / PhD (Chemical Technology) / Unrestricted

In this study, lanolin alcohol as well as lanolin alcohol-povidone films (1:1 . 5) were investigated as a potential drug delivery system. The in vitro drug release from these films was studied in terms of the effect of agitation, film thickness and drug concentration. The rate of release of Cortisol from lanolin alcohol films was not affected by the intensity of agitation. Moreover, the film matrix was found to remain essentially intact throughout the release process. Further analysis of the data revealed that Higuchi's diffusion-controlled granular matrix model explained the mechanism of Cortisol release from such films. The results of drug release from lanolin alcohol povidone films have shown that although Higuchi's release rate constant was found to be independent of film thickness, it was affected by the intensity of agitation, since the rate constant was found to increase as agitation speed was increased, especially at low speeds. In addition, povidone was found to leach out of the film matrix along with the drug. These factors, in conjunction with further analysis of the drug, explained the failure of this film system to conform to the matrix-controlled diffusion model. The release rate of Cortisol from this film system was found to follow first-order dependence on drug concentration. The drug was found to be completely insoluble in lanolin alcohol, and slightly soluble in povidone. Povidone was found to enhance the solubility of Cortisol in water.

Aim of thesis was to acquaint with architecture and process of signal in systems using broadband LTE wireless technology. Thesis in detail is described physical layer of system. Next there is described comparison of LTE and WiMAX and table with all present systems. Thesis also is contained information about tested LTE system in real traffic. Next aim was created simulation of LTE system in downlink and uplink. Interface was created for easier configuration of each characteristics of transfer and type of interference of useful signal. This interface is contained control of whole simulation and presentation of measured values. Measured data were processed into graphs, which show dependence of error rate BER on C/N of useful and interference signal.

Orientador: Luiz Francisco Malmonge / Resumo: Os fertilizantes de liberação modificada têm conquistado âmbitos cada vez maiores nas pesquisas e em utilizações agrícolas devido a suas principais características de menores perdas de nutrientes e por seu menor custo, que envolve menos aplicações no campo e menores quantidades de fertilizantes utilizados, comparado aos fertilizantes convencionais. Este trabalho teve como objetivo elaborar fertilizantes com possível comportamento de liberação modificada, através da incorporação do fosfato de potássio monobásico (KH2PO4) no polímero quitosana, contribuindo, dessa forma, com as três fontes de nutrientes primários essenciais requeridos pelas plantas: nitrogênio, fósforo e potássio, por apenas dois recursos. Foram elaboradas duas amostras diferentes para posterior comparação, análise e aplicação. Os métodos utilizados no preparo das amostras foram: gotejamento em solução básica coagulante e casting. Foram feitas soluções de 8% de quitosana (m/v) dissolvidas em soluções de 5% de ácido acético, e subsequentemente foi adicionado o KH2PO4 (em diferentes concentrações para análise e para aplicação agrícola, foi usada a concentração de 60% (m/m) em relação à massa de quitosana). Foram feitas Microscopia eletrônica de varredura (MEV) para análise morfológica das amostras, Energia dispersiva de raios-X (EDX) para constatação dos elementos contidos nas amostras, o estudo da liberação dos nutrientes em solução aquosa (em pHs 5,4 e 6,7) e por fim, as amostras foram aplicadas em mudas de alf... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Modified-release fertilizers have been increasingly used in research and in agricultural uses due to their main characteristics of lower nutrient losses and their lower cost, which involves fewer applications in the field and less quantities of utilized fertilizers, compared to the conventional ones. This work aimed to elaborate fertilizers with possible modified release behavior, through the incorporation of monobasic potassium phosphate (KH2PO4) in the chitosan polymer, thus contributing with the three sources of essential primary nutrients required by plants: nitrogen, phosphorus and potassium, from only two resources. Two different samples were prepared for later comparison, analysis and application. The methods used in preparing the samples were: dripping in a basic coagulant solution and casting. Solutions of 8% chitosan (w/v) were prepared dissolved in solutions of 5% acetic acid, and subsequently KH2PO4 was added (in different concentrations for analysis and for agricultural application, the concentration of 60% (w/w) in relation to the chitosan mass). Scanning electron microscopy (SEM) was performed for the morphological analysis of the samples, energy dispersive X ray (EDX) to verify the elements contained in the samples, the study of the release of nutrients in aqueous solution (at pH 5.4 and 6, 7) and finally, the samples were applied to lettuce seedlings for comparative effect and material efficiency. The results of the EDX spectra showed that in the samples made... (Complete abstract click electronic access below) / Mestre