• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 6
  • 6
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Photocatalytic Properties of Zinc Selenide/Cadmium Sulfide Core-shell Nanoparticles

Perera, Jayalath Pathirannehelage Dimuthu Nuwan 30 August 2013 (has links)
No description available.
2

Granulometria do calcÃrio para podeiras comerciais submetidas ou nÃo à iluminaÃÃo artificial / Limestone particle size subjected to commercial podeiras or not will floodlit

Regina PatrÃcia de Souza Xavier 04 March 2013 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / The experiment was conducted to evaluate the effects of particle size of the limestone and the use of artificial light on feeding behavior, performance, egg quality and bone of laying hens. A total of 300 Hisex White hens at 18 weeks of age, distributed in a completely randomized design in factorial 5 x 2, with 5 replicates of 6 birds. The factors studied were 5 granulometries obtained by increasing the proportion of coarse limestone (0, 25, 50, 75 and 100%) compared to 2 types of thin and light, with and without artificial light. No significant interaction between factors (size x lighting program) for all parameters evaluated on performance, egg quality and bone. There was also no significant effect on the level of coarse limestone in diets on performance and egg quality, however had an effect on bone quality. Among the light programs, showed that the use of artificial light showed eggs with higher Haugh Units compared to birds that received only natural light. With respect to feeding behavior no significant interaction between factors limestone, light and time. However, significant effects of the interaction (light and time), there was a higher consumption in birds without artificial light in relation to artificial light during the hours of 6am to 9h40min and 12:40 to 17:40 and the interaction effect (limestone and time) , it was observed that at the time of 6am to 9h40min, increased consumption, corresponded to the gradual increase in the ration of coarse limestone. For laying hens in the first laying cycle, created in geographic coordinates that developed in the research, changes in particle size of limestone provided an improvement in bone quality of the birds and the use of artificial light may favor albumen quality as Haugh unit. / O experimento foi realizado com o objetivo de avaliar os efeitos da granulometria do calcÃrio e do uso da luz artificial sobre o comportamento alimentar, desempenho, qualidade do ovo e Ãssea de poedeiras comerciais. Foram utilizadas 300 poedeiras Hisex White com 18 semanas de idade, distribuÃdas em um delineamento inteiramente casualizado, em esquema fatorial 5 x 2, com 5 repetiÃÃes de 6 aves. Os fatores estudados foram 5 granulometrias obtidas pelo aumento da proporÃÃo de calcÃrio grosso (0, 25, 50, 75 e 100%) em relaÃÃo ao fino e 2 tipos de iluminaÃÃo, com e sem luz artificial. NÃo houve interaÃÃo significativa entre os fatores (granulometria x programa de luz) para os parÃmetros avaliados sobre desempenho, qualidade do ovo e Ãssea. TambÃm nÃo houve efeito significativo do nÃvel de calcÃrio grosso na raÃÃo sobre o desempenho e qualidade do ovo, entretanto apresentou efeito sobre a qualidade Ãssea. Entre os programas de luz, observou-se que o uso de luz artificial apresentou ovos com maiores valores de unidade Haugh em relaÃÃo Ãs aves que receberam apenas luz natural. Com relaÃÃo ao comportamento alimentar nÃo houve interaÃÃo significativa entre os fatores calcÃrio, luz e horÃrio. Contudo, houve efeito significativo entre a interaÃÃo (luz e horÃrio), observou-se um maior consumo nas aves sem luz artificial em relaÃÃo aos com luz artificial nos horÃrios de 6h Ãs 9h40min e 12h40min Ãs 17h40min e efeito na interaÃÃo (calcÃrio e horÃrio), observou-se que no horÃrio de 6h Ãs 9h40min, o aumento do consumo, correspondeu ao aumento gradativo do calcÃrio grosso na raÃÃo. Para poedeiras comerciais no primeiro ciclo de postura, criadas nas coordenadas geogrÃficas em que se desenvolveu a pesquisa, as mudanÃas na granulometria do calcÃrio proporcionou uma melhora na qualidade Ãssea das aves e a utilizaÃÃo da luz artificial pode favorecer a qualidade do albÃmen medida em unidade Haugh.
3

Optimal strength of carbon fibre overwrapped composite high-pressure vessels

Numbi, M. N. 08 December 2021 (has links)
M. Tech. (Mechanical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / The purpose of this study was to design a composite overwrapped pressure vessel by combining the best optimal structural options. This study investigated the effects of constituents such as fibre and shell thickness, on the bursting strength. Thereafter, these constituents were combined in order to achieve optimization of strength for an improved sustainable composite pressure vessel. The analytical method was carried out using the Tsai-wu failure theorem. The developed analytical equations were solved with Matlab 2016 software to determine composite fibre and shell thickness. With variation of the vessel’s liner, a total of 56 parts were created on two different profiles with purpose of generating of vessels resistant to bursting failure. Henceforth, the structural integrity of fibre imparted into the design was optimally analyzed at an angle of 55⁰, through the negative and positive directions. The shell thickness overwrapping the liner, being as well an influential factor to this optimization, was, therefore, analyzed on symmetrical and asymmetrical lamination patterns. The optimal fibre and shell thickness range were thereafter determined on a first ply failure and hoop stress threshold approach. Additionally, the identified optimal range of pressure vessel constituents were numerically validated, on Abaqus/CAE software, to have a degree of reassurance on the result generated, using Hashin failure criteria. Optimal design with improved strength and weight factor was therefore achieved by combining the generated optimal vessel constituents yielded from Minitab software version 2016. The generated results of the study revealed no change on the fibre thickness determined with respect to direction. For shell thickness on the other hand, asymmetrical pattern was identified as the desired sequence of lamination. In addition, with two profiles considered in the research, the composite constituents were found for a p value of 0.066, to be optimal on profile 1 at 0.0048 mm of liner, 0.0005 mm of fibre and 0.0027 mm of shell. The profile 2 on the other hand, revealed optimization of liner at 0.0095 mm, fibre at 0.0021 mm and shell at 0.0055 mm. Through combination of these ultimate constituents the response optimizer on Minitab software generated optimal bursting strength with factor of 4% improvement with a weight reduction of 33% compared to the stainless steel vessel. It was, therefore, concluded that profile 1 was the most optimal with hoop strength of 123.43 MPa, Von Mises of 178.56 MPa and Tresca of 179.48 MPa.
4

Värme- och massflöde i precisionsgjuteri : Optimering och undersökning av simuleringsparametrar för precisionsgjutning

Kuivamäki, Daniel, Mohseni, Mohammad January 2019 (has links)
För att kunna prediktera fel under processen precisionsgjutning, används simulering som ett verktyg att bestämma hur detaljer skall gjutas. Det finns flertalet parametrar som är möjliga att manipulera eller ändra. För att komma så nära ett verkligt scenario som möjligt behöver dessa parametrar optimeras mot verkligheten. Syftet med detta arbete är att analysera faktorer som påverkar värmeöverföring för att sedan presentera optimeringsförslag åt TPC Components AB mot de gjorda mätningarna. Detta görs för att kunna förutsäga till exempel hur snabbt ett föremål kyls i processen och hur det påverkar det slutgiltiga resultatet. Resultat från de optimerade simuleringarna jämförs mot ett praktiskt försök och även TPC Components tidigare standard utvärderas mot arbetets optimerade simuleringar. En viktig fråga är att undersöka varför simuleringsprogrammet inte blir identiskt med verkligheten och hur detta undersöks. Känslighetsanalyser utgör därmed en stor del av arbetet och det är av vikt att undersöka enskilda parametrar för att få en uppfattning om vad som påverkar resultatet och vad som går att bortse från. Resultatet av arbetet visar att ändrade parametrar för indata vid precisionsgjutning i TPC Components AB:s vakuumprocess har resulterat i en mer pålitlig simulering. Simuleringen bygger nu på vetenskapliga bevis och faktiska uppmätningar under processen för att kunna simulera så likt verkligheten som möjligt. Arbetet resulterar i att färre gjutförsök innan godkänt tillvägagångssätt för nya detaljer behövs, då simulering kommer att visa resultat närmare verkligheten. Arbetet har förbättrat TPC Components simuleringsarbete vilket kommer påverka både arbetstid, kostnader och miljö på ett positivt sätt. / Simulation of investment casting play a big role for prediction of problems in the process. TPC Components AB need their simulations to be optimised against the practical process in order to get results as close as possible to the results from real practice. This thesis is mapping the parameters sensitivity against TPC’s earlier standards to put forward what parameters the result is depending on. The optimization of the parameters is towards measurement of heat and time and practical trial in order to get a scientific ground. The heat transfer for complicated structure needs to be simulated in order to get a reasonable value to work with. Results shows that TPC’s earlier model of simulation have lack of measurement and important parameters are based on assumptions. The work done gave TPC a model closer to the real practice which can both mean faster decisions of how to cast new products and less costly practical trials.
5

Granulometria do calcário para podeiras comerciais submetidas ou não á iluminação artificial / Limestone particle size subjected to commercial podeiras or not will floodlit

Xavier, Regina Patrícia de Souza January 2013 (has links)
XAVIER, Regina Patrícia de Souza. Granulometria do calcário para podeiras comerciais submetidas ou não á iluminação artificial. 2013. 51 f. : Dissertação (Mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Zootecnia, Programa de Pós-Graduação em Zootecnia. Fortaleza-CE, 2013. / Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-08-10T15:43:45Z No. of bitstreams: 1 2013_dis_rpsxavier.pdf: 489341 bytes, checksum: 41b075add288fff4301df196cba6837d (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-12T12:21:58Z (GMT) No. of bitstreams: 1 2013_dis_rpsxavier.pdf: 489341 bytes, checksum: 41b075add288fff4301df196cba6837d (MD5) / Made available in DSpace on 2016-08-12T12:21:58Z (GMT). No. of bitstreams: 1 2013_dis_rpsxavier.pdf: 489341 bytes, checksum: 41b075add288fff4301df196cba6837d (MD5) Previous issue date: 2013 / The experiment was conducted to evaluate the effects of particle size of the limestone and the use of artificial light on feeding behavior, performance, egg quality and bone of laying hens. A total of 300 Hisex White hens at 18 weeks of age, distributed in a completely randomized design in factorial 5 x 2, with 5 replicates of 6 birds. The factors studied were 5 granulometries obtained by increasing the proportion of coarse limestone (0, 25, 50, 75 and 100%) compared to 2 types of thin and light, with and without artificial light. No significant interaction between factors (size x lighting program) for all parameters evaluated on performance, egg quality and bone. There was also no significant effect on the level of coarse limestone in diets on performance and egg quality, however had an effect on bone quality. Among the light programs, showed that the use of artificial light showed eggs with higher Haugh Units compared to birds that received only natural light. With respect to feeding behavior no significant interaction between factors limestone, light and time. However, significant effects of the interaction (light and time), there was a higher consumption in birds without artificial light in relation to artificial light during the hours of 6am to 9h40min and 12:40 to 17:40 and the interaction effect (limestone and time) , it was observed that at the time of 6am to 9h40min, increased consumption, corresponded to the gradual increase in the ration of coarse limestone. For laying hens in the first laying cycle, created in geographic coordinates that developed in the research, changes in particle size of limestone provided an improvement in bone quality of the birds and the use of artificial light may favor albumen quality as Haugh unit. / O experimento foi realizado com o objetivo de avaliar os efeitos da granulometria do calcário e do uso da luz artificial sobre o comportamento alimentar, desempenho, qualidade do ovo e óssea de poedeiras comerciais. Foram utilizadas 300 poedeiras Hisex White com 18 semanas de idade, distribuídas em um delineamento inteiramente casualizado, em esquema fatorial 5 x 2, com 5 repetições de 6 aves. Os fatores estudados foram 5 granulometrias obtidas pelo aumento da proporção de calcário grosso (0, 25, 50, 75 e 100%) em relação ao fino e 2 tipos de iluminação, com e sem luz artificial. Não houve interação significativa entre os fatores (granulometria x programa de luz) para os parâmetros avaliados sobre desempenho, qualidade do ovo e óssea. Também não houve efeito significativo do nível de calcário grosso na ração sobre o desempenho e qualidade do ovo, entretanto apresentou efeito sobre a qualidade óssea. Entre os programas de luz, observou-se que o uso de luz artificial apresentou ovos com maiores valores de unidade Haugh em relação às aves que receberam apenas luz natural. Com relação ao comportamento alimentar não houve interação significativa entre os fatores calcário, luz e horário. Contudo, houve efeito significativo entre a interação (luz e horário), observou-se um maior consumo nas aves sem luz artificial em relação aos com luz artificial nos horários de 6h às 9h40min e 12h40min às 17h40min e efeito na interação (calcário e horário), observou-se que no horário de 6h às 9h40min, o aumento do consumo, correspondeu ao aumento gradativo do calcário grosso na ração. Para poedeiras comerciais no primeiro ciclo de postura, criadas nas coordenadas geográficas em que se desenvolveu a pesquisa, as mudanças na granulometria do calcário proporcionou uma melhora na qualidade óssea das aves e a utilização da luz artificial pode favorecer a qualidade do albúmen medida em unidade Haugh.
6

Návrh separátoru / Design of separator

Bukal, Oldřich January 2013 (has links)
Diploma thesis is focused on design and strenght calculation of the separator according to ČSN EN 13 445. Introductory part introduce problems with design of separators, in the other parts there is a design and strenght calculation of separator according to ČSN EN 14 445, unfired pressure vessels, part 3 - Design, FEM analysis in ANSYS Workbench and stress categorization of the results.

Page generated in 0.0516 seconds