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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.
721

Développement et évaluation de formulations pour inhalation à base d'anticancéreux dans le cadre du traitement des tumeurs pulmonaires / Development and evaluation of formulations for inhalation based on anticancer drugs for the treatment of lung tumors

Wauthoz, Nathalie 07 December 2011 (has links)
Les tumeurs pulmonaires, qu’elles soient primaires (principalement représentées par le cancer du poumon non-à-petites cellules) ou secondaires (métastases), causent la mort de plusieurs centaines de milliers de personnes par an à travers le monde. Malgré les modalités de traitements existantes, un plateau thérapeutique a été atteint avec un taux de survie à 5 ans de maximum 15%. Actuellement, il est connu que le cancer du poumon non-à-petites cellules ainsi que les métastases sont intrinsèquement résistants à l’apoptose.<p>Pour apporter des réponses aux principales problématiques rencontrées avec l’administration systémique de la chimiothérapie conventionnelle qui est principalement constituée d’agents pro-apoptotiques, nous avons développé des formulations à base d’agents antinéoplasiques aux propriétés anticancéreuses non pro-apoptotiques qui sont destinées à être administrées de manière localisée par la voie inhalée. Il faut savoir que l’inhalation est la voie d’administration préférentielle des principales affections respiratoires telles que l’asthme, la bronchopneumonie chronique obstructive et la mucoviscidose. <p>La première partie de ce travail a consisté à produire et à évaluer des formulations à base de témozolomide destinées à être administrées chez la souris porteuse de pseudo-métastases pulmonaires (issues d’un mélanome expérimental, le modèle B16F10), soit via la voie intraveineuse (iv) conventionnelle soit via la voie inhalée à l’aide d’un dispositif endotrachéal approprié. La suspension pour inhalation a été produite à l’aide de technique de réduction de taille et a été stabilisée à l’aide de phospholipides compatibles avec la voie pulmonaire. L’activité anticancéreuse in vitro a été vérifiée pour le témozolomide formulé sous forme de suspension pour inhalation et de solution intraveineuse par rapport à du témozolomide non formulé sur des lignées de cellules cancéreuses de cancer humain NSCLC A549, de glioblastome humain T98G et de mélanome murin B16F10. Cette dernière lignée a été utilisée pour générer les pseudo-métastases pulmonaires chez la souris en injectant les cellules de mélanomes dans la voie systémique via la veine caudale. La reproductibilité de la dose et de l’aérosol générés à partir de la suspension pour inhalation à l’aide du dispositif d’administration endotrachéal et la déposition des gouttelettes dans les poumons de la souris ont pu être respectivement évaluées avec précision par une méthode de quantification du témozolomide qui a été validée par nos soins, par des techniques de diffraction laser et par des techniques de microscopie à fluorescence et d’analyse d’images histologiques. Enfin, l’activité antitumorale in vivo et la tolérance des traitements conventionnels ou localisés ont été vérifiées chez la souris porteuse de ces pseudo-métastases pulmonaires B16F10. Les résultats ont montré que le dispositif endotrachéal utilisé permettait de produire des doses et des aérosols reproductibles et de déposer les gouttelettes d’aérosol profondément dans les poumons des souris. De plus, lors de l’étude in vivo, les traitements administrés étaient bien tolérés et la dose de témozolomide administré sous forme de suspension pour inhalation à l’aide du dispositif endotrachéal avait permis d’obtenir une efficacité antitumorale similaire à une dose similaire de témozolomide administrée par la voie iv conventionnelle. De plus, 11% (3/27) de souris « long-survivantes » avaient été observées avec le groupe traité par inhalation trois fois par semaine pendant trois semaines consécutives et les poumons de ces long-survivants avaient présenté une éradication quasi complète des tumeurs pulmonaires. Ce phénomène n’avait pas été observé dans les groupes de souris traitées de manière conventionnelle.<p>Ensuite, la seconde partie de notre travail a consisté en l’élaboration du témozolomide sous forme de poudres sèches pour inhalation destinées à être délivrées à l’aide d’un dispositif à poudre sèche à usage humain. Pour ce faire, nous avons développé les poudres sèches pour inhalation à l’aide de techniques de réduction de taille pour microniser la poudre de départ et d’atomisation pour évaporer le solvant et élaborer un enrobage autour des particules micronisées. La nature de l’enrobage était soit hydrophile soit lipophile. Ensuite les caractéristiques physicochimiques telles que les propriétés thermiques, les propriétés cristallines, la distribution de taille particulaire et la morphologie des formulations de poudre sèche pour inhalation ont été évalués à l’aide de techniques appropriées telles que la calorimétrie différentielle à balayage, la diffraction des rayons X sur poudre, la diffraction de la lumière laser et la microscopie électronique à balayage. Les profils de déposition pulmonaire et de dissolution ont été respectivement déterminés in vitro à l’aide de l’essai de la pharmacopée européenne utilisant l’impacteur à cascade multi-étages et d’un test de dissolution adapté aux formes pulmonaires. Les quatre formulations élaborées présentaient des caractéristiques physicochimiques intéressantes pour la stabilité à long-terme de la substance active et des formulations. De plus, deux formulations de poudre sèche pour inhalation (les formulations F1 et F2) présentaient des propriétés aérodynamiques tout à fait attrayantes avec une fraction minimale de poudre déposée au niveau du tractus respiratoire supérieure et une fraction maximale de poudre déposée au niveau du tractus respiratoire inférieur où se localisent les tumeurs pulmonaires. De plus, l’ensemble des formulations ont montré que la fraction sélectionnée des particules fines des poudres sèches pour inhalation libérait 75% du témozolomide dans le liquide simulant le fluide pulmonaire endéans les dix premières minutes du test de dissolution in vitro adapté aux formes pulmonaires. <p>Enfin, nous avons comparé l’efficacité et la tolérance in vivo d’une de nos formulations de poudre sèche de témozolomide pour inhalation administrée soit sous forme de suspension, soit sous forme de poudre sèche, à l’aide du dispositif endotrachéal approprié chez la souris porteuse de pseudo-métastases pulmonaires. L’uniformité de la dose délivrée par les différents dispositifs a été évaluée à l’aide d’une technique quantitative validée. Les résultats de cette étude ont montré qu’en administrant une formulation de poudre sèche sous forme d’un mélange de poudres plutôt que sous forme d’une suspension liquide, les doses en témozolomide à administrer pour obtenir une efficacité comparable était au moins deux fois moins élevées. Cependant, le dispositif endotrachéal pour les formulations de poudre présentait plus de variabilité au niveau de la dose délivrée que le dispositif endotrachéal pour les formulations liquides ce qui induit une variabilité dans les doses délivrées. Pour clôturer ce travail, nous avons appliqué certaines techniques que nous avons développées pour le témozolomide à une nouvelle molécule de synthèse, le trivanillate polyphénolique 13c, qui montre des propriétés anticancéreuses intéressantes dans le cadre des tumeurs pulmonaires. En effet, une méthode quantitative a été développée et a été validée. Une étude de pré-formulation et des essais de formulation pour produire une suspension, des complexes d’inclusion et des microparticules lipidiques ont été entrepris avec de relativement bons résultats pour les complexes d’inclusion élaborés avec des gamma cyclodextrines qui permettaient d’augmenter la solubilité dans l’eau de la molécule de 13c d’un facteur d’au moins 1,5×106. De plus, les particules de 13c montraient la particularité de se solubiliser dans un mélange dichlorométhane/éthanol (1 :1 v/v) ce qui nous a permis d’élaborer des microparticules lipidiques pour lesquelles les propriétés de mouillage devront être améliorées dans l’avenir./<p>Primary lung tumors, mainly represented by non-small-cell lung cancers (cancers NSCLC), or secondary lung tumors (metastasis) cause the death of hundred thousand human beings worldwide. Despite the therapeutic modalities used, the five-year survival rate reaches only 15%. Nowadays, it is known that cancers NSCLC and metastasis are intrinsically resistant to apoptosis.<p>To overcome the main problems occurring with the systemic delivery of conventional chemotherapy which are mainly constituted of non-specific and non selective pro-apoptotic agents, we have developed some formulations based on non pro-apoptotic antineoplasic drugs which are designed to be delivered by a localized administration, the inhalation. Indeed, inhalation is the preferential route to treat the main pulmonary affections such as asthma, chronic obstructive pulmonary disease or cystic fibrosis.<p>The first part of this work consisted to produce and evaluate temozolomide-based formulations designed to be delivered to mice bearing pulmonary pseudo-metastases (using a experimental melanoma, the B16F10 model), either by the conventional intravenous (iv) route or by inhalation using an endotracheal device appropriate to mice. The suspension for inhalation was produced by means of a high pressure homogenizing technique using phospholipids compatible with the lungs to stabilize the suspension. The in vitro anticancer activity was evaluated for both temozolomide-based formulations in comparison with non-formulated temzolomide on three cancer cell lines, a human NSCLC cancer cells (A549), a human glioblastoma cancer cells (T98G) as positive control and a murine melanoma cancer cells (B16F10). The latter was used to generate lung tumors in mice by injecting the melanoma cells by iv. Reproducibility of delivered dose and generated aerosol by the endotracheal device from the suspension for inhalation and the deposition of droplets in the mouse lungs were precisely evaluated by means of a validated HPLC determination method, a laser diffraction technique and fluorescent microscopy and histological image analysis, respectively. Then, the tolerance and the antitumor efficacy of iv or inhaled temozolomide-based treatments were evaluated on mice bearing pulmonary pseudo-metastases B16F10. The results showed that endotracheal device produced reproducible doses and aerosols and that the aerosol droplets were deposited deeply in the mouse lungs. Moreover, the temozolomide-based treatments were well tolerated in terms of weight evolution and the inhaled based-temozolomide treatments were able to get the same antitumor efficacy in terms of median survival rate as the conventional iv based-temozolomide treatments delivered at a same frequency. Moreover with the group treated by inhalation three times a week during three consecutive weeks, 11% (3/27) mice survived with an almost complete eradication of lung tumors which was not observed with the groups treated by conventional route.<p>Then, the second part of our work consisted to produce temozolomide-based dry powders for inhalation able to be delivered with a dry powder inhaler for human use. We developed the dry powders for inhalation using a high-pressure homogenizing technique to micronize temozolomide particles and then spray-drying technique to coat temozolomide microparticles. The coating was either hydrophilic or lipophilic. Then, the physicochemical characteristics such as thermal or crystalline properties, the particle size distribution and the particle morphology were evaluated for the four dry powders for inhalation by means of differential scanning calorimetry, x-ray powder diffraction, laser light scattering and scanning electron microscopy, respectively. The in vitro pulmonary deposition and dissolution were respectively determined by European pharmacopeia assay for the aerodynamic assessment of fine particles using a multi-stage liquid impinger and by dissolution test optimized for inhaler products. The four formulations produced presented physicochemical properties promoting long-term stability of temozolomide and formulations.Moreover, two of them (dry powder without coating or with a thin lipid coating) showed attractive aerodynamic properties with a minimal fraction of powder deposited in the oropharyngeal and tracheal zones and maximal fraction deposited in the lungs (almost 50% of the nominal dose) where the lung tumors are localized. Moreover, fine particle fraction of all formulations showed a fast release and dissolution of temozolomide with more than 75% of temozolmide dissolved within 10 minutes in the simulated lung fluid during the in vitro dissolution test optimized for dry powders for inhalation.<p>Then, we compared the in vivo antitumor efficacy and tolerance of one of dry powders for inhalation on mice bearing pulmonary pseudo-metastases B16F10. The dry powder for inhalation was administered either by dispersing it as a extemporaneous suspension able to be delivered by the endotracheal device for liquid forms or by mixing it with a spray-dried diluent able to be delivered by the endotracheal device for dry powders. The uniformity of delivered dose by the different endotracheal device was evaluated by a validated quantitative method. The results showed that the delivery of the powder mixture presented the same antitumor efficacy as the extemporaneous suspension but for a half dose of temozolomide. However, the endotracheal device for dry powders presented a higher variability of delivered dose than the endotracheal device for liquid forms.<p>Finally, we apply the pulmonary application on a polyphenol developed in the Faculty of Pharmacy, the molecule 13c, that showed very interesting in vitro anticancer properties against lung tumors. So, a quantitative method was developed and was validated. A preformulation studie was performed and formulation developements are on-going.<p> / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished
722

Gecko-Inspired Electrospun Flexible Fiber Arrays for Adhesion

Najem, Johnny F. 19 July 2012 (has links)
No description available.
723

En utvärdering av Non-Invasive Break-Up Time och Tear Break-Up Time hos heltidsstuderande vid Linnéuniversitetet / An evaluation of Non-Invasive Break-Up Time and Tear Break-Up Time in full-time students at Linnaeus University

Svedin, Lina, Norrby, Rebecka January 2024 (has links)
Syfte: Syftet med studien var att utvärdera NIBUT (Non-Invasive Break-Up Time) och TBUT (Tear Break-Up Time) hos heltidsstuderande vid Linnéuniversitetet samt bidra till en ökad förståelse av ögonhälsan hos denna grupp. Metod: Tårfilmens stabilitet kontrollerades med NIBUT och TBUT, tiden mättes direkt efter en blinkning till första uppsprickningen av tårfilmens yta eller ny blinkning. NIBUT utfördes icke invasivt i Sirius och TBUT mättes i biomikroskop med fluorescein. Deltagarna fick inledningsvis svara på en enkät som gjorde det möjligt att analysera insamlad data utifrån ålder, kön, termin, skärmtid och poäng på DEQ-5 (5-Item Dry Eye Questionnaire). Svaren från DEQ-5 möjliggjorde att resultaten från NIBUT och TBUT mätningarna kunde jämföras mot upplevda symtom på torra ögon. Resultat: Studien inkluderade 36 studenter i åldersspannet 18–39 år (medianålder 23 år, IQR 5,25 år). NIBUT och TBUT visade en positiv signifikant korrelation (p &lt;0,001). En kortare TBUT korrelerade negativt med en högre totalpoäng på DEQ-5 (p = 0,004) samt antalet terminer som studerats (p = 0,025). NIBUT visade inte några liknande samband. Referensvärdet för torra ögon diagnostisering med hjälp av NIBUT och TBUT är en tid &lt;10 sekunder. Över hälften av deltagarna i studien, NIBUT 58% och TBUT 53%, hade en nedsatt break-up time &lt;10 sekunder. Vilket kan vara en indikation för torra ögon problematik. Slutsats: Denna studie visar att det finns ett signifikant samband mellan NIBUT och TBUT mätningarna. Kortare TBUT har visat en signifikant korrelation med högre totalpoäng på DEQ-5, likaså har signifikanta samband mellan TBUT och fler lästa terminer konstaterats. Trots korrelationen mellan NIBUT och TBUT påverkades resultaten av skillnader mellan de två mätmetoderna. / Purpose: The purpose of the studies was to evaluate NIBUT (Non-Invasive Break-Up Time) and TBUT (Tear Break-Up Time) in full-time students at Linnaeus University and to contribute to an increased understanding of the eye health of this group. Method: The stability of the tear film was checked with NIBUT and TBUT, the time was measured directly after a blink to the first break-up of the tear film surface or a new blink. NIBUT was performed non-invasively in Sirius and TBUT was measured in a biomicroscope with fluorescein. The participants initially had to answer a questionnaire that made it possible to analyze collected data based on age, sex, number of semesters studied, screen time and score on the DEQ-5 (5-Item Dry Eye Questionnaire). The responses from the DEQ-5 allowed the results from the NIBUT and TBUT measurements to be compared against perceived symptoms of dry eye. Results: The study included 36 students in the age range 18–39 years (median age 23 years, IQR 5.25 years). NIBUT and TBUT showed a positive significant correlation (p &lt;0.001). A shorter TBUT correlated negatively with a higher DEQ-5 total score (p = 0.004) as well as the number of semesters studied (p = 0.025). NIBUT did not show any similar correlations. The reference value for dry eye diagnosis using NIBUT and TBUT is a time &lt;10 seconds. Over half of the participants in the study, NIBUT 58% and TBUT 53%, had a reduced break-up time &lt;10 seconds. Which can be an indication of dry eye problems. Conclusion: This study shows that there is a significant connection between the NIBUT and TBUT measurements. Shorter TBUT has shown a significant correlation with higher total scores on the DEQ-5, likewise significant connections between TBUT and more semesters read have been established. Despite the correlation between NIBUT and TBUT, the results were influenced by differences between the two measurement methods.
724

Characterizing quality and composition of beef derived from cattle fed steam-flaked corn diets with combinations of dry-rolled corn and dried distiller’s grains with solubles

Black, Patricia Lynne January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / A trial was conducted replacing portions of steam-flaked corn with either dry-rolled corn or dried distiller’s grains with solubles to evaluate effects on performance, carcass characteristics, carcass composition, meat color stability, and meat sensory attributes. Seven hundred crossbred yearling heifers (302 ± 65 kg initial BW) were used in a randomized complete block experiment with a 2 x 2 factorial arrangement of treatments. All diets contained steam-flaked corn (SFC), and factors consisted of the levels of dry-rolled corn (DRC; 0 or 25%) and dried corn distiller’s grains with solubles (DDGS; 0 or 25%). Results revealed no interactions between DRC and DDGS in terms of effects on feedlot performance, and only minor interactive effects were observed for carcass characteristics and meat quality attributes. Feedlot performance and carcass characteristics were not affected by the addition of DRC or DDGS (P > 0.05). Carcass composition and meat quality attributes were measured to determine if fat content of carcasses was altered by feeding DDGS. Diet had no significant effects, as carcasses from the four treatments contained similar amounts of separable portions of muscle, adipose, and bone; and similar percentages of protein, moisture, and ether extract. Compositions of both adipose and muscle tissue were evaluated to assess differences in fatty acid profile. Minimal effects were noted on the fatty acid profiles of the muscle and adipose tissue from cattle fed DDGS or DRC. Feeding cattle DDGS decreased alpha tocopherol (vitamin E) content of meat (P < 0.05). Meat quality attributes were largely unaffected by addition of DRC or DDGS to the diet, as retail color display life, lipid oxidation, sensory attributes, and heterocyclic amine concentrations were not different among treatments. Overall, DRC or DDGS can replace portions of SFC without negatively altering feedlot performance, carcass characteristics, meat composition, or meat quality attributes.
725

Strategy for developing an ecological sanitation system at the Barrage informal settlement

Mokoena, Mita January 2015 (has links)
The Barrage informal settlement (BIS) is a peri-urban community of about 300 people resident on private land close to the banks of the Vaal River in Gauteng South Africa. The study focuses on the living and sanitation conditions in which people find themselves. Measured against the Millennium Development Goals (MDGs) BIS and its residents clearly are far from meeting MDG 7 target 7 C. For the purposes of this study the researcher investigated ecological sanitation (EcoSan) as an alternative solution for the current local sanitation conundrum. Residents either use the veld or a dysfunctional pit system. The data used for the project was generated both in a qualitative and quantitative mode. Semi-structured interviews were randomly conducted. Participants were requested and subsequently assisted in completing a questionnaire. There were also several focus group discussions for gathering relevant data. The researcher tried to form an impression of the perceptions of community members in terms on the type of sanitation system they wished to use. Community members actively engaged in strategies aimed to find out how they perceive sanitation, potable water supply and matters of hygiene. The findings revealed dissatisfaction regarding to current conditions in BIS. Residents are uncertain because the land on which they reside on does not belong to them. This, in turn, creates uncertainty and feelings of insecurity, about the relevance of a potential water-based sanitation system. At the same time members of the community indicated they had no interest in a dry toilet system. Neither are they keen on the use of community ablution blocks (CABs) as alternative. Residents showed no willingness and are also not prepared to pay for sanitation because they cannot afford it. The dilemma is that residents are at the mercy of Emfuleni Local Municipality (ELM) and the private owners of the land on which they reside. Where do we find the solution to all of the issues? Participatory deliberation strategies were used to determine which system of sanitation local residents preferred. They clearly came out in favour of the Water Bank concept as a feasible sanitation system option. However, as a result of the unfulfilled promises of Emfuleni Local Municipality (ELM) and landowners the community remains in a state of uncertainty about the permanence of the BIS.
726

Strategy for developing an ecological sanitation system at the Barrage informal settlement

Mokoena, Mita January 2015 (has links)
The Barrage informal settlement (BIS) is a peri-urban community of about 300 people resident on private land close to the banks of the Vaal River in Gauteng South Africa. The study focuses on the living and sanitation conditions in which people find themselves. Measured against the Millennium Development Goals (MDGs) BIS and its residents clearly are far from meeting MDG 7 target 7 C. For the purposes of this study the researcher investigated ecological sanitation (EcoSan) as an alternative solution for the current local sanitation conundrum. Residents either use the veld or a dysfunctional pit system. The data used for the project was generated both in a qualitative and quantitative mode. Semi-structured interviews were randomly conducted. Participants were requested and subsequently assisted in completing a questionnaire. There were also several focus group discussions for gathering relevant data. The researcher tried to form an impression of the perceptions of community members in terms on the type of sanitation system they wished to use. Community members actively engaged in strategies aimed to find out how they perceive sanitation, potable water supply and matters of hygiene. The findings revealed dissatisfaction regarding to current conditions in BIS. Residents are uncertain because the land on which they reside on does not belong to them. This, in turn, creates uncertainty and feelings of insecurity, about the relevance of a potential water-based sanitation system. At the same time members of the community indicated they had no interest in a dry toilet system. Neither are they keen on the use of community ablution blocks (CABs) as alternative. Residents showed no willingness and are also not prepared to pay for sanitation because they cannot afford it. The dilemma is that residents are at the mercy of Emfuleni Local Municipality (ELM) and the private owners of the land on which they reside. Where do we find the solution to all of the issues? Participatory deliberation strategies were used to determine which system of sanitation local residents preferred. They clearly came out in favour of the Water Bank concept as a feasible sanitation system option. However, as a result of the unfulfilled promises of Emfuleni Local Municipality (ELM) and landowners the community remains in a state of uncertainty about the permanence of the BIS.
727

Experimental and computational study of multiphase flow in dry powder inhalers

Fouda, Yahia M. January 2014 (has links)
Dry Powder Inhalers (DPIs) have great potential in pulmonary drug delivery; the granular powder, used as active ingredient in DPIs, is ozone friendly and the operation of DPIs ensures coordination between dose release and patient inhalation. However, the powder fluidisation mechanisms are poorly understood which leads to low efficiency of DPIs with 10-35 % of the dose reaching the site of action. The main aim of this thesis is to study the hydrodynamics of powder fluidisation in DPIs, using experimental and computational approaches. An experimental test rig was developed to replicate the process of transient powder fluidisation in an impinging air jet configuration. The powder fluidisation chamber was scaled up resulting in a two dimensional particle flow prototype, which encloses 3.85 mm glass beads. Using optical image processing techniques, individual particles were detected and tracked throughout the experimental time and domain. By varying the air flow rate to the test section, two particle fluidisation regimes were studied. In the first fluidisation regime, the particle bed was fully fluidised in less than 0.25 s due to the strong air jet. Particle velocity vectors showed strong convective flow with no evidence of diffusive motion triggered by inter-particle collisions. In the second fluidisation regime, the particle flow experienced two stages. The first stage showed strong convective flow similar to the first fluidisation regime, while the second stage showed more complex particle flow with collisional and convective flow taking place on the same time and length scales. The continuum Two Fluid Model (TFM) was used to solve the governing equations of the coupled granular and gas phases for the same experimental conditions. Sub-models for particle-gas and particle-particle interactions were used to complete the model description. Inter-particle interactions were resolved using models based on the kinetic theory of granular flow for the rapid flow regime and models based on soil mechanics for the frictional regime. Numerical predictions of the first fluidisation regime showed that the model should incorporate particle-wall friction and minimise diffusion, simultaneously. Ignoring friction resulted in fluidisation timing mismatch, while increasing the diffusion resulted in homogenous particle fluidisation in contrast to the aggregative convective fluidisation noticed in the experiments. Numerical predictions of the second fluidisation regime agreed well with the experiments for the convection dominated first stage of flow up to 0.3 s. However, later stages of complex particle flow showed qualitative discrepancies between the experimental and the computational approaches suggesting that current continuum granular models need further development. The findings of the present thesis have contributed towards better understanding of the mechanics of particle fluidisation and dense multiphase flow in DPI in particular, and particle bed fluidisation using impinging air jet in general. The use of TFM for predicting high speed convective granular flows, such as those in DPIs, is promising. Further studies are needed to investigate the form of particle-particle interactions within continuum granular flow models.
728

Intensifying rice-fallow systems in Southeast and South Asia with grain legumes and/or dry season crops: analysis using field experiment and simulation

Dewi, Elsa Rakhmi 06 July 2016 (has links)
No description available.
729

Enquiry into sewage pump station problems with specific focus on removing solids

Tulleken, Joubert 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: There is a general lack of published research on sewage pump station problems and the removal of solids in South African sanitary sewers. Research was undertaken to investigate the problems at sewage pump stations by means of site visits, interviews, literature reviews and laboratory experiments. An in-depth literature study is presented on sewage pump stations, pump station problems and solids in sewers. The problems at sewage pump stations were categorised into identifiable groups with possible generalised solutions. The site visits and literature review indicated a specific lack of knowledge regarding screening baskets used to remove solids at sewage pumping stations. This led to the experimental testing of a screening basket on full scale in a controlled environment to develop an efficiency index for screening baskets. The efficiency index was determined using fuzzy logic methodology with predetermined solids load, basket height above the sump level and solids retention time. The fuzzy logic proved that the basket is best operated halfway submerged, after one hour retention time and with degradable solids in the system. The literature compiled and problems identified in this study were used as the backbone for the development of a conceptual Decision Support Tool (DST) for sewage pump stations. The DST is aimed at requiring limited inputs and providing maximum knowledge output and is presented as a software tool in MS Excel format. The functionality was added by applying visual basic applications in MS Excel user forms. The idea of developing a DST is to assist designers, sewage service providers and operators with understanding the various components and for problem identification pertaining to sewage pump stations in the future. The DST is relatively self-explanatory with a user friendly visual interface that is easy to operate. This study sets the scene for further research into efficiency indices pertaining to different components of sewage pump stations and their application in comprehensive sewage pump decision support tools. / AFRIKAANSE OPSOMMING: Daar is 'n algemene gebrek aan gepubliseerde navorsing oor probleme met rioolpompstasies en die verwydering van ongewenste voorwerpe in Suid-Afrikaanse sanitêre rioolsisteme. Navorsing is gedoen om die probleme by rioolpompstasies te ondersoek deur middel van terreinbesoeke, onderhoude, literatuurstudie en eksperimente in „n laboratorium. 'n Omvattende literatuurstudie is op rioolpompstasies, probleme by pompstasies en ongewenste voorwerpe in rioolnetwerke gedoen. Die probleme by rioolpompstasies is verdeel in identifiseerbare groepe met moontlike oplossings. Die terreinbesoeke en literatuuroorsig het 'n spesifieke gebrek aan kennis met betrekking tot skermmandjies, wat gebruik word om ongewenste voorwerpe by rioolpompstasies te verwyder, aangedui. Dit het gelei tot die eksperimentele toetsing van 'n skermmandjie deur die volskaalse opstelling in 'n beheerde omgewing om 'n doeltreffendheidsindeks vir skermmandjies in die praktyk te ontwikkel. Die doeltreffendheidsindeks is bepaal deur gebruik te maak van “fuzzy logic” metodologie met voorafbepaalde insette naamlik, die mandjie se hoogte bo die watervlak, soort ongewenste voorwerpe en die tyd wat die voorwerpe aan water blootgestel is. Die “fuzzy logic” bewys dat die mandjie die beste werking toon, halfpad onder die water, na „n een uur van blootstelling aan water en met degradeerbare voorwerpe in die stelsel. Die literatuur wat saamgestel is en probleme wat in hierdie studie geïdentifiseer is, is gebruik as die inhoud vir die konseptuele “Decision Support Program” (DST) vir rioolpompstasies. Die DST het ten doel om met beperkte insette die maksimum kennis te verskaf en word aangebied as 'n sagteware instrument in MS Excel formaat. Die funksionaliteit is bygevoeg deur die toepassing van die “visual basic applications” in MS Excel gebruikersvorms. Die doel van die ontwikkeling van 'n DST is om ontwerpers, riooldiensverskaffers en operateurs te help om die verskillende funksies en probleem-identifikasie met betrekking tot rioolpompstasies te begryp. Die DST is relatief selfverduidelikend met 'n gebruikers vriendelike visuele koppelvlak wat maklik is om te bedryf. Hierdie studie bied die basis vir verdere ondersoek na die doeltreffendheidsindekse met betrekking tot die verskillende komponente van rioolpompstasies en die toepassing daarvan in omvattende rioolpomp “DSTs”.
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Environmental impact assessment (water pollution) of a floating dock in Yam O

Cho, Tat-wing, Asam., 曹達榮. January 1997 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

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