Typescript. / Bibliography: leaves [180]-190. / xviii, 218 l illus

A greenhouse study was carried out to investigate the effectiveness of soil-applied silicon (Si) with that of foliar applications for sorghum growth. Silicon sources were soil-applied as calmasil (calcium silicate) at two rates (4 and 8t/ha) and foliar applied Si including pure K-silicate, K-humate and K-fulvate (all three foliar treatments at rates of 300 and 600 ppm). Another treatment included soil applied calmasil plus low rate of foliar applied K-humate. The soils used for the greenhouse trial were Cartref, Glenrosa, Nomanci and Fernwood. Results indicated that application of calcium silicate to the soil before planting increased sorghum yield and Si uptake in three of the four soils. Silicon uptake from different experimental treatments followed the order: Calmasil 8t/ha > calmasil 4t/ha ~ calmasil + 300 ppm K-humate> K-humate = K-fulvate = pure-K silicate = control. Foliar sprays were ineffective at increasing yield, Si content of the plant tissues or Si uptake. The concentrations of exchangeable Ca, Mg as well as soil pH were significantly increased by calmasil treatments. Extractable AI concentrations were also reduced due to the Iiming effect of calcium silicate and also possibly formation of insoluble aluminosilicates. The yield response to applied calmasil seemed to be primarily related to its Iiming effect and reductions in extractable AI in the Cartref, Glenrosa and Nomanci soils. The dry matter yield was highest in Fernwood and lowest in Cartref soil. However, there was no significant yield response to calmasil in Fernwood soil which had an initial pH of 5.8 and insignificant extractable AI concentrations. Therefore application of calcium silicate had no significant effect on extractable AI concentration in this soil. Yield response to calmasil may also have been partly due to direct positive effects of applied Si on crop growth through mechanisms such as increased photosynthetic rate and reduced transpiration rate, Addition of calmasil increased the concentrations of Si in the plant tissues and reduced those of N, P and Kin Nomanci and Fernwood soils respectively. This indicates that nutrient interactions were occurring in the plant. It was concluded that foliar-application is not an effective way of applying Si to a Siresponsive crop such as sorghum when growing in soils low in extractable soil Si. This is because Si is accumulated in plant tissues in similar amounts to macronutrients. It was also concluded that in future, studies of crop response to applied Si should include the use of non-Iiming source of Si (e.g. silicic acid) so as to separate a liming effect of calcium silicate from effect of applied Si. In a laboratory study, the effects of applied silicic acid, calcium silicate and calcium hydroxide on levels of extractable P in two Si-deficient soils were investigated. Two soils (Fernwood and Nomanci soils) were treated with two rates of P and three soil amendments (calcium silicate, calcium hydroxide and silicic acid) and incubated for six weeks at room temperature. Phosphorus was extracted using Truog, AMBIC and resin methods, and levels of exchangeable and solution AI and extractable and solution Si were also measured. Application of calcium silicate and calcium hydroxide increased soil pH in both soils while silicic acid additions had no significant effect compared with the control. The pH increase was much greater in the Fernwood than Nomanci soil because of the low buffering capacity of the sandy Fernwood soil. Exchangeable AI and concentrations of monomeric and total AI in soil solution generally followed the order: control ~ silicic acid> calcium silicate> calcium hydroxide. The lowering of soluble AI concentrations in the silicic acid treatments was attributed to formation of insoluble aluminosilicate compounds while that in the calcium silicate and calcium hydroxide treatments was attributed to their Iiming effects causing a rise in pH. Concentrations of Si in soil solution were lower in the calcium hydroxide than the control treatment suggesting the solubility of Si decreased with increased pH. Additions of both Si sources increased Si concentrations in solution and the effect was more marked for the calcium silicate treatment. This was attributed to formation of insoluble aluminosilicates in the silicic acid treatment. Concentrations of H2S04extractable Si with treatment did not closely follow the same trends as those for Si concentrations in soil solution. That is, levels of extractable Si were very much higher in the calcium silicate than silicic acid treatment in both soils. In addition, concentrations of extractable Si in the calcium hydroxide treatment were similar to control in the Nomanci soil, while for the Fernwood soil, concentrations in the calcium hydroxide treatment were exceptionally high. It was suggested that liming with calcium silicate or calcium hydroxide had rendered some Si-containing compounds in the soil acid-extractable and that the nature of acid-extractable Si fraction need further study in future. The quantities of P extracted from the two soils by the various extractants followed the order: Truog> AMBle> resin. The greatest increase in extractable P induced by additions of P was recorded for Truog P and the least for resin P. The effects of Iiming (addition of calcium silicate or calcium hydroxide) on extractable P levels differed depending on the soil and extractant used with increase, decrease or no effect being recorded. Such results confirm the complexity of lime and P interactions which occur in acid soils. Additions of silicic acid had no effect on levels of extractable P, compared to control. It was suggested that the reason for this was that phosphate is adsorbed to AI and Fe oxide surfaces much more strongly than silicate. As a result, additions of Si are ineffective at increasing extractable P levels. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Although silicon (Si) has not yet been recognized as an essential nutrient element, its application to sugarcane (Saccharum officinarum L.) has proved to be beneficial. Since optimum crop production depends on the maintenance of adequate plant nutrients in the soil, there is a need in the South African sugar industry for a reliable index for assessing the requirement for supplemental silicon (Si) in soils, particularly in reducing the risk of Eldana saccharina stalk borer infestation in cane. The objective of this study was to assess Si availability in soils, to select a suitable Si extraction method and a critical value for determining when a response is likely. For this purpose, five acid soils (representing. some of the most important agricultural soil groups used for sugarcane production in the sugar belt) were used in October 2004, in the lAKE WILSON glasshouse of the South African Sugarcane Research Institute (SASRI) based at Mount Edgecombe. Except for the Arcadia form soil with an initial Si content of 1.2 mmol kg- I as estimated using the O.OlM H2S04 + (NH4)zS04) extractant, soils representing the other five soil forms namely Cartref, Glenrosa, Longlands and Nomanci; exhibited a sub-optimal Si content of not more than 4.0 mmol kg-I. Sorghum was used as a plant crop and sugarcane as a ratoon crop because of their Si accumulator status. Three different Si sources: calmasil, slagment and wollastonite; with respectively 9.85, 15.20, and 5.25% Si content were applied at increasing rates of 0, 3 and 6 tons ha- 1 as Si fertilizers. Silicon (Si) was extracted from untreated and treated soils by utilizing six different extractants, (1) O.OlM H2S04 + (NH4)2S04; (2) Distilled water; (3) 0.025M H2S04; (4) 0.5M CH3COOH; (5) 0.5M CH3COONH4pH 4.8; and (6) O.OlM CaCh.2H20. The amount of soil Si extracted followed the order: 0.025M H2S04 > 0.5M CH3COOH > O.OlM H2S04 + (NH4)2S04 > O.OlM CaCh.2H20 > 0.5M CH3COON~ pH 4.8 > distilled water. Soil Si extracted by 0.025M H2S04 was significantly correlated with soil exchangeable cations,. CEC, clay content, cane biomass yield, cane Si uptake and increasing rates of applied Si. Averaged over all soil forms investigated, the increases in dry biomass yield and Si uptake ranged. from 18% to 154% for sorghum; and from 23% to 85% for cane respectively. Even though the highest increases (%) in cane biomass yield and Si uptake were obtained on a Nomanci form soil with initial poor fertility status, the highest means were obtained on an Arcadia form soil with the highest Si initial content. There was no difference between different Si sources in their ability to influence cane biomass yield and Si uptake, and therefore the supply to the soils. Even though the lower and higher Si source rates were not different from each other, they increased cane yield and Si uptake, indicating that Si was undoubtedly beneficial for sugarcane. The Si critical levels for different soils as estimated by 0.025M H2S04 were 6.0 mmol kg-1 (168 mg kg-I) for Arcadia; 2.6 mmol kg-I (64 mg kg-I) for Cartrel; 2.5 mmol kg-I (64 mg kg-I) for Glenrosa; 1.6 mmol kg-I (45 mg kg-I) for Longlands; and 2.4 mmol kg-I (67 mg kg-i) for Nomanci form soils. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

The constantly tightening emission regulations demand the engines to be moreefficient, to get more power out of smaller engines. Higher engine loads andcomponent temperatures are causing more stresses to engine components. Therefore,a company that produces engines wanted to study if it would be possible to increasethe capabilities of the components by optimising the used material. In this final project work, a cylinder head will be studied. The cylinder heads for theengines are made of ductile cast iron. The limits of that material are near safety limits,and therefore a better material is needed. In this work are some previous studiesanalysed and tried to find how to optimise the used material. The optimised materialshould have better thermal conductivity properties combined with sufficient strengthproperties. Previous studies were analysed to gather knowledge of the elements that affect thematerial parameters. Those studies showed that copper, silicon, pearlite fraction, andthe use of chills are the elements to be optimised. Silicon and pearlite fraction waschosen as optimisation parameters because of their effect on the thermal conductivityand strength properties. Copper was chosen as an optimisation variable due to its effecton the pearlite formation. Chills were used to affect the cooling rate and thereby thepearlite formation. The work was made using MAGMASOFT™ simulation software to simulate cylinderhead casting. The simulated cylinder head was divided into 4 parts for the simulations.For those sections were then set targets for pearlite fraction according to previousstudies. The silicon content was kept constant in the simulation, based on the studiespresented in this work. Copper content was simulated with variations from 0 to 0.7weight-%, and chill heights were simulated from 20 to 60 mm and without chills. After simulating the different variables, the results were analysed. Then the selectedcasting simulation result was mapped to finite element simulation mesh to include thelocal material parameters to finite element simulation. With the finite elementsimulation, the estimated lifetime of the component was simulated. By analysing the casting simulation results, an optimal combination was found. Theoptimal material parameters for a cylinder head casting would be copper 0.5weight-%, silicon 1.9 weight-% and chills thicker than 40 mm on the flame plate. Theoptimised material gives more possibilities to develop engines even further when thecomponent demands are growing.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-09T21:25:32Z No. of bitstreams: 1 EWERTON GONÇALVES DE ABRANTES - DISSERTAÇÃO PPGHT 2014..pdf: 742061 bytes, checksum: fb0ea15cd43e74db00440e44ab2d3d33 (MD5) / Made available in DSpace on 2018-05-09T21:25:32Z (GMT). No. of bitstreams: 1 EWERTON GONÇALVES DE ABRANTES - DISSERTAÇÃO PPGHT 2014..pdf: 742061 bytes, checksum: fb0ea15cd43e74db00440e44ab2d3d33 (MD5) Previous issue date: 2014-02-26 / Capes / A berinjela (Solanum melongena L.) é uma hortaliça de fruto pertencente à família solanácea considerada exigente em nitrogênio para uma produção adequada. Dessa forma, o fornecimento de silício (Si) pode aumentar a eficiência da adubação nitrogenada e reduzir as doses a serem aplicadas. O trabalho teve por objetivo avaliar o efeito da adubação com N e Si e da interação N x Si sobre o crescimento, aspectos fisiológicos, nutrição nitrogenada e silicatada, visando ao aumento da eficiência da adubação nitrogenada, o aumento da produtividade e da qualidade dos frutos da berinjela. Dois experimentos, em delineamento inteiramente casualizado, foram conduzidos no Centro de Ciências e Tecnologia Agroalimentar (CCTA/UFCG), Campus de Pombal-PB, com plantas de berinjela, cultivar “Embú”. No primeiro, os tratamentos foram constituídos por um arranjo fatorial 5 x 4, compreendendo 5 doses de N (25; 125; 250; 350 e 500 mg dm-3) e 4 doses de Si (0; 75; 150 e 200 mg dm-3) aplicados via radicular com quatro repetições. No segundo, os tratamentos foram constituídos por um arranjo fatorial 5 x 2, sendo 5 doses N (25; 125; 250; 350 e 500 mg dm-3) e 2 doses de Si (sem silício e aplicação foliar de uma solução 10 mmol L-1 de Si) e seis repetições. Na fase de pré-florescimento foram avaliados o crescimento (produção de matéria seca das folhas, caule e de raízes e o índice de área foliar); as trocas gasosas, quais sejam taxa fotossintética, condutância estomática, taxa de transpiração e concentração intercelular de CO2; os teores e acúmulos das frações de nitrogênio (NO3-, NH4+, total e orgânico), a estimativa da eficiência de utilização do N (EUN) e o teor de Si nas folhas. No segundo experimento, além das variáveis citadas, foram avaliados também o número de frutos por planta, produção por planta, o peso médio dos frutos, o diâmetro longitudinal e transversal, a firmeza, °Brix, o pH da polpa, o teor de vitamina C e a acidez titulável. A adubação nitrogenada proporcionou aumentos na produção de matéria seca, nas trocas gasosas, nos teores das frações de N assim como seus respectivos acúmulos, elevou os atributos de qualidade dos frutos, porém diminuiu o teor de Si nas folhas e a eficiência de utilização de N (EUN). A adubação silicatada aplicada via radicular elevou o teor e acúmulo de N-NH4+ nas folhas, o acúmulo de N-NH4+ nas raízes, e o teor de Si nas folhas, o teor e o acúmulo de N-NO3- nas raízes, e diminuiu o teor e o acúmulo de N-NO3- nas folhas, sem influenciar no crescimento e nas trocas gasosas. A adubação silicatada aplicada via foliar influenciou negativamente nas taxas de transpiração e fotossintética; diminuiu os teores de N-NH4+ nas folhas, N-NO3-, Norgânico e N-total no caule, e aumentou o teor de N-NO3- nas raízes; influenciou positivamente na EUN; proporcionou aumentos no tamanho dos frutos, no °Brix, e diminuiu a acidez titulável dos frutos. Concluiu-se que a berinjela respondeu positivamente a adubação nitrogenada, proporcionando aumentos no crescimento, nas trocas gasosas, nos teores das frações de N, porém com efeito negativo na EUN e no teor foliar de Si. O silício exerceu influência nos teores foliares das frações de N e nitrato nas raízes, e na qualidade dos frutos. / The eggplant (Solanum melongena L.) is a vegetable fruit that belongs to the solanaceous family,considered demanding in nitrogen for adequate production. So, the supply of silicon (Si) may increase the efficiency of nitrogen fertilization and reduces the doses to be applied. The study aimed to evaluate the fertilization effect with N and Si, and Si x N interaction on growth, physiological aspect, silicon and nitrogen nutrition, aiming at increasing the nitrogen efficiency fertilizer, and also increasing of productivity and eggplant fruit quality. Two experiments in completely randomized design were conducted at the Centro de Ciências e Tecnologia Agroalimentar (CCTA/UFCG), Campus Pombal - PB, with eggplants cultivate "Embu". In the first experiment, treatments consisting of a 5 x 4 factorial arrangement, comprising 5 N rates (25, 125, 250, 350 and 500 mg dm-3) and 4 Si rates (0, 75, 150 and 200 mg dm-3) applied via root with four replications. In the second experiment, treatments consisting of a 5 x 2 factorial arrangement, with 5 N rates (25, 125, 250, 350 and 500 mg dm-3) and 2 Si rates (silicon and without foliar application of a 10 mmol L-1 Si) and six replications. During pre-flowering, were evaluated growth (dry matter production of leaves, stems and roots, and leaf area index); gas exchanges, which are photosynthetic rate, stomatal conductance, transpiration rate and intercellular CO2 concentration; the contents and accumulation of fractional nitrogen (NO3-, NH4+, and total and organic), the estimated N use efficiency (NUE) and Si content in the leaves. In the second experiment, in addition to the aforementioned variables were also evaluated the number of fruits per plant, yield per plant, average fruit weight, the longitudinal and transverse diameter, firmness, °Brix, the pH of the pulp, the vitamin content C and titratable acidity. Nitrogen fertilization increased the yield in dry matter production, gas exchange, the levels of N fractions as well as their accumulation, increased the quality attributes of the fruit, but decreased the Si content in leaves and N utilization efficiency (EUN). Silicon fertilization applied via roots elevated the content and accumulation of N-NH4+ in the leaves , the accumulation of N-NH4+ in the roots , and the Si content in the leaves , the concentration and accumulation of N-NO3- in roots and decreased and N-NO3- accumulation in leaves without influence on growth and gas exchange. Silicon fertilization foliar applied negatively influenced the rates of transpiration and photosynthesis; decreased levels of N-NH4+ in leaves , N-NO3-, N-organic and N-total in the stem, and increased the content of N-NO3- in roots; positively influenced the NUE; yielded increases in fruit size, in °Brix, and decreased acidity of the fruits. It was concluded that eggplant responded positively to nitrogen fertilization, providing increases in growth, gas exchange, the levels of N fractions, but with a negative effect on NUE and leaf content in Si. Silicon exerted influence on foliar concentrations of fractions N and nitrate in roots, and fruit quality.

Kontroll av zinkskikt på monterat räckesmaterial som görs ute i fält saknar en fastställd metod. Zinktjockleken har ett minimum tjocklekskrav enligt den svenska standarden ISO 1461:2009, som bestäms av dimensionen på ståldetaljens tjocklek. Trafikverket begär att med hjälp av detta examensarbete kunna begränsa antal mätningar på plats, då kan det ta allt för mycket tid och arbetsresurser i fall det skulle behövas kontroll av väg-och bro räckesanläggningar från beställaren. Sannolikhetsläran och stickprov i statistik hjälper oss att begränsa antalet mätningarna på skyddsanordningarna som görs ute i fält. Med hjälp av normalfördelning kommer man fram till den efter strävade metoden, som med en rimlig arbetsinsats ger en rättvisbild av skikttjockleken på monterat räckesmaterial. Vid variation av varmförzinkaren på vägräckesanläggningar undersöker man varje leverantörs räckesdel för sig, alltså man mäter zinktjockleken på en varmförzikare för sig, kontrollerar zinkskiktstjockleken på de och tar slutsatser sedan går man vidare till nästa tillverkare. Om vägräckena är mindre än 30 stycken mäter man zinktjockleken på respektive anläggning. För beräkning av zinkskiktstjockleken på monterad räckesmaterial börjar man med 30 mätningar och användning av den centrala gränsvärde satsen för att approximera till normalfördelning och analysera resultatet. Det slutliga resultatet av examensarbetet är ett Excelprogram med inmatade formler. Excel programmet är ett hjälpmedel för framtagning av 95 % konfidensintervall. Med hjälp av detta intervall kan man ta slutsatser om zinkskiktet på vägräckena uppfyller kravet eller inte och kunna komma fram till ett resultat. Om kravet ligger i intervallet eller store än intervallet är materialet godkänt. / Control of zinc coating on assembled railing materials made on site lacks a common methodology. Zinc coating should have a minimum thickness requirements according to the Swedish standard ISO 1461:2009, which is determined by the dimension of the steel thickness. Trafikverket expects that with help from this thesis it could limit the number of measurements on site, otherwise it will take too much time and labor resources, in case control of road and bridge railing systems are required from the customer.  Probabilities and sampling in statistics helps us to limit the number of measurements of the protective devices that are made in the field. Using normal distribution, one arrive at the element of method that with reasonable effort gives a fair picture of the layer thickness of the assembled railing materials. Upon variation of the galvanizers on road barrier systems, each part is investigated separately by measuring zinc thickness of a galvanizers, checking the zinc coating thickness on them, take conclusions and later on investigate the next manufacturer. If a crash barrier is less than 30 pieces, the zinc coating thickness is measured at each facility by itself. For calculation of the zinc coating thickness on a mounted railing material one begins with 30 measurements and the use of the central limit theorem to approximate it to normal distribution and analyze the results. The final result of the thesis is an Excel program with input formulas. The Excel program is a tool for producing 95% confidence interval. Using this interval, one can make conclusions that if the zinc coating on a crash barrier fulfills the requirement or not and later on be able to come up with a result. If the requirement is in the interval or larger than the interval, the material is approved.