1000 resultados para Salminen, Timo
Resumo:
A goiabeira (Psidium guajava L.) é uma espécie que vem se tornando de grande importância em diversas regiões do Brasil, principalmente no Estado de São Paulo, maior produtor nacional. Desde 1985, a UNESP/FCAV, Câmpus de Jaboticabal, vem desenvolvendo um programa de melhoramento genético da goiabeira, com o objetivo de obter plantas com boas características agronômicas e com frutos que possam ser destinados tanto à industrialização quanto ao consumo na forma de fruta fresca. Partindo-se de 219 plantas, oriundas de diversos cruzamentos, e após dez anos de avaliação, chegou-se à cultivar Século XXI, cujas principais características são: planta muito produtiva com ciclo precoce (130 dias da floração à colheita), frutos grandes, com polpa espessa, róseo-avermelhada, ótimo sabor e com poucas e pequenas sementes.
Resumo:
This thesis gives an overview of the validation process for thermal hydraulic system codes and it presents in more detail the assessment and validation of the French code CATHARE for VVER calculations. Three assessment cases are presented: loop seal clearing, core reflooding and flow in a horizontal steam generator. The experience gained during these assessment and validation calculations has been used to analyze the behavior of the horizontal steam generator and the natural circulation in the geometry of the Loviisa nuclear power plant. The cases presented are not exhaustive, but they give a good overview of the work performed by the personnel of Lappeenranta University of Technology (LUT). Large part of the work has been performed in co-operation with the CATHARE-team in Grenoble, France. The design of a Russian type pressurized water reactor, VVER, differs from that of a Western-type PWR. Most of thermal-hydraulic system codes are validated only for the Western-type PWRs. Thus, the codes should be assessed and validated also for VVER design in order to establish any weaknesses in the models. This information is needed before codes can be used for the safety analysis. Theresults of the assessment and validation calculations presented here show that the CATHARE code can be used also for the thermal-hydraulic safety studies for VVER type plants. However, some areas have been indicated which need to be reassessed after further experimental data become available. These areas are mostly connected to the horizontal stem generators, like condensation and phase separation in primary side tubes. The work presented in this thesis covers a large numberof the phenomena included in the CSNI code validation matrices for small and intermediate leaks and for transients. Also some of the phenomena included in the matrix for large break LOCAs are covered. The matrices for code validation for VVER applications should be used when future experimental programs are planned for code validation.
Resumo:
This study compares different rotor structures of permanent magnet motors with fractional slot windings. The surface mounted magnet and the embedded magnet rotor structures are studied. This thesis analyses the characteristics of a concentrated two-layer winding, each coil of which is wound around one tooth and which has a number of slots per pole and per phase less than one (q < 1). Compared to the integer slot winding, the fractional winding (q < 1) has shorter end windings and this, thereby, makes space as well as manufacturing cost saving possible. Several possible ways of winding a fractional slot machine with slots per pole and per phase lessthan one are examined. The winding factor and the winding harmonic components are calculated. The benefits attainable from a machine with concentrated windingsare considered. Rotor structures with surface magnets, radially embedded magnets and embedded magnets in V-position are discussed. The finite element method isused to solve the main values of the motors. The waveform of the induced electro motive force, the no-load and rated load torque ripple as well as the dynamic behavior of the current driven and voltage driven motor are solved. The results obtained from different finite element analyses are given. A simple analytic method to calculate fractional slot machines is introduced and the values are compared to the values obtained with the finite element analysis. Several different fractional slot machines are first designed by using the simple analytical methodand then computed by using the finite element method. All the motors are of thesame 225-frame size, and have an approximately same amount of magnet material, a same rated torque demand and a 400 - 420 rpm speed. An analysis of the computation results gives new information on the character of fractional slot machines.A fractional slot prototype machine with number 0.4 for the slots per pole and per phase, 45 kW output power and 420 rpm speed is constructed to verify the calculations. The measurement and the finite element method results are found to beequal.
Resumo:
In this study, a model for the unsteady dynamic behaviour of a once-through counter flow boiler that uses an organic working fluid is presented. The boiler is a compact waste-heat boiler without a furnace and it has a preheater, a vaporiser and a superheater. The relative lengths of the boiler parts vary with the operating conditions since they are all parts of a single tube. The present research is a part of a study on the unsteady dynamics of an organic Rankine cycle power plant and it will be a part of a dynamic process model. The boiler model is presented using a selected example case that uses toluene as the process fluid and flue gas from natural gas combustion as the heat source. The dynamic behaviour of the boiler means transition from the steady initial state towards another steady state that corresponds to the changed process conditions. The solution method chosen was to find such a pressure of the process fluid that the mass of the process fluid in the boiler equals the mass calculated using the mass flows into and out of the boiler during a time step, using the finite difference method. A special method of fast calculation of the thermal properties has been used, because most of the calculation time is spent in calculating the fluid properties. The boiler was divided into elements. The values of the thermodynamic properties and mass flows were calculated in the nodes that connect the elements. Dynamic behaviour was limited to the process fluid and tube wall, and the heat source was regarded as to be steady. The elements that connect the preheater to thevaporiser and the vaporiser to the superheater were treated in a special way that takes into account a flexible change from one part to the other. The model consists of the calculation of the steady state initial distribution of the variables in the nodes, and the calculation of these nodal values in a dynamic state. The initial state of the boiler was received from a steady process model that isnot a part of the boiler model. The known boundary values that may vary during the dynamic calculation were the inlet temperature and mass flow rates of both the heat source and the process fluid. A brief examination of the oscillation around a steady state, the so-called Ledinegg instability, was done. This examination showed that the pressure drop in the boiler is a third degree polynomial of the mass flow rate, and the stability criterion is a second degree polynomial of the enthalpy change in the preheater. The numerical examination showed that oscillations did not exist in the example case. The dynamic boiler model was analysed for linear and step changes of the entering fluid temperatures and flow rates.The problem for verifying the correctness of the achieved results was that there was no possibility o compare them with measurements. This is why the only way was to determine whether the obtained results were intuitively reasonable and the results changed logically when the boundary conditions were changed. The numerical stability was checked in a test run in which there was no change in input values. The differences compared with the initial values were so small that the effects of numerical oscillations were negligible. The heat source side tests showed that the model gives results that are logical in the directions of the changes, and the order of magnitude of the timescale of changes is also as expected. The results of the tests on the process fluid side showed that the model gives reasonable results both on the temperature changes that cause small alterations in the process state and on mass flow rate changes causing very great alterations. The test runs showed that the dynamic model has no problems in calculating cases in which temperature of the entering heat source suddenly goes below that of the tube wall or the process fluid.
Resumo:
O presente trabalho teve por objetivo avaliar o efeito do anelamento do tronco realizado em diferentes épocas, sobre a antecipação da maturação dos cachos da videira 'Rubi', na região noroeste do Paraná. Foram estudados os seguintes tratamentos: testemunha sem anelamento; anelamento com 5-6ºBrix de sólidos solúveis totais (SST) no suco das bagas; anelamento com 7-8ºBrix de SST no suco das bagas, e anelamento com 9-10ºBrix de SST no suco das bagas. O delineamento experimental foi o de blocos ao acaso, com quatro tratamentos e cinco repetições, sendo cada parcela composta por uma planta. O anelamento consistiu na remoção de uma porção da casca do tronco, de aproximadamente 3-4 mm de largura, utilizando-se de um incisor de lâmina dupla, a uma altura de 1,5 m do solo. Foram avaliados semanalmente, a partir da instalação do experimento, o teor de SST e a acidez titulável (AT) do suco. Por ocasião da colheita, compararam-se o peso e o comprimento dos cachos, e o peso, a largura e o comprimento das bagas. Para a estimativa do período ótimo para maturação de cada tratamento, empregou-se análise de regressão, tendo como parâmetro a relação SST/AT = 20. O maior período de antecipação da maturação em relação à testemunha sem anelamento foi obtido quando o suco das bagas apresentava teor de SST entre 5-6ºBrix, ou seja, 8 dias. Não foram observadas diferenças entre os tratamentos quanto às características físicas dos cachos e das bagas.
Resumo:
Mushroom picking has become a widespread autumn recreational activity in the Central Pyrenees and other regions of Spain. Predictive models that relate mushroom production or fungal species richness with forest stand and site characteristics are not available. This study used mushroom production data from 24 Scots pine plots over 3 years to develop a predictive model that could facilitate forest management decisions when comparing silvicultural options in terms of mushroom production. Mixed modelling was used to model the dependence of mushroom production on stand and site factors. The results showed that productions were greatest when stand basal area was approximately 20 m2 ha-1. Increasing elevation and northern aspect increased total mushroom production as well as the production of edible and marketed mushrooms. Increasing slope decreased productions. Marketed Lactarius spp., the most important group collected in the region, showed similar relationships. The annual variation in mushroom production correlated with autumn rainfall. Mushroom species richness was highest when the total production was highest.
Resumo:
Um substrato composto por resíduos da agroindústria canavieira vem sendo utilizado com êxito para a produção de mudas de algumas espécies frutíferas e florestais. Assim, o objetivo deste trabalho foi avaliar o uso deste substrato comparando-o com outros recomendados para a produção de mudas de maracujazeiro-amarelo. Foram avaliados sete substratos: 1- Bagaço de cana + torta de filtro (3:2; v:v); 2- Bagaço de cana + torta de filtro (3:2; v:v) + pulverização foliar semanal com NPK; 3- Bagaço de cana + torta de filtro (3:2; v:v) + 7,3 kg m-3 de Osmocote® (14-14-14); 4- Plantmax®; 5- Plantmax® + pulverização foliar semanal com NPK; 6- Plantmax® + 7,3 kg m-3 Osmocote® (14-14-14), e 7- Areia + esterco bovino + vermiculita (1:1:1; v:v:v) + NPK. De modo geral, as mudas cultivadas no substrato composto por resíduos da agroindústria canavieira e no substrato comercial, ambos fertilizados com adubo de liberação lenta, foram as que apresentaram melhor estado nutricional, comprovado pelos teores de nutrientes associados ao ótimo crescimento. Portanto, o substrato composto pela mistura bagaço de cana e torta de filtro (3:2; v:v) fertilizado com 7,3 kg m-3 de Osmocote® (14-14-14) pode ser utilizado para a produção de mudas de maracujazeiro-amarelo.
Resumo:
Tutkimuksen tavoitteena on selvittää epänormaalien tuottojen esiintymistä Suomen osakemarkkinoilla. Kiinnostuksen kohteena ovat erityisesti lyhyen aikavälin tuotot. Tutkimusongelman taustalla on käsitys, että osingonilmoitus vaikuttaa osakekursseihin joko negatiivisesti tai positiivisesti.
Resumo:
Työn päätavoitteena on ennakkoluulottomasti etsiä uudenlaista ratkaisua Mantsinen -lastausnosturin taittopuomiin ja pyrkiä löytämään kevyempi tarkoitukseen sopiva rakenne hyödyntämällä lujia teräksiä. Työ painottuu eri ratkaisuvaihtoehtojen kartoittamiseen ja niiden arviointiin elementtimenetelmää hyödyntäen. Arvioinnissa painotettiin tarkoituksen mukaisuutta ja väsymiskestävyyttä. Tutkimus suoritetaan vertailemalla vanhaa ja uutta ratkaisua keskenään. Työssä havaittiin, että ottamalla huomioon hitsattujen lujien terästen väsymisominaisuudet jo suunnittelussa, voidaan saada aikaan kevyempiä ja väsymisen kannalta kestävämpiä ratkaisuja.
Resumo:
Artikkelissa kerrotaan Jyväskylän yliopiston erityispedagogiikan laitoksella valmistuneesta Ulla Ojalammin ja Marjatta Leppäsen pro gradu -tutkielmasta "Fasilitointi - faktaa, fiktiota vai filunkia?, joka esittelee huolellisesti valmistellun kokeellisen tutkimuksen fasilitoidun kommunikaation toimivuudesta.