This thesis is aimed at biology, presence and methods of weeds regulation on a land planted with permanent grasses. Lately, ruderal weed species have been spreading uncontrollably throughout the lawns. It is very difficult to control their occurrence and also very economically challenging. Therefore, the farms should focus more on the possibilities of preventing excessive weed infestation and they should also define and apply the cheapest and the most favorable precautions. On the grassland, which belongs to the ZD Třebelovice, were observed the most abundant weed species. The weeds which occurred the most were: Taraxacum Officinale, Rumex Obtusifolius L, Ranunculus Repens L., Geranium Pratense L., and Urtica dioica L. The influence of the individual hay cuts on the occurrence of the chosen weed species was monitored. The influence of various herbicides was also the matter of observance. The componential task was to appraise the achieved effect after applying chosen herbicides on the weed species.

This dissertation presents novel vibrational control strategies for mechanical control-affine systems with high-frequency, high-amplitude inputs. Since these control systems use high-frequency, zero-mean, periodic inputs, averaging techniques are widely used in the analysis of their dynamics. By studying their time-averaged approximations, new properties of the averaged dynamics of this class of systems are revealed. Using these properties, the problem of input optimization of vibrational control systems was formulated and solved by transforming the problem to a constrained optimization one. Geometric control theory provides powerful tools for studying the control properties of control-affine systems. Using the concepts of vibrational and geometric controls and averaging tools, a closed-loop control strategy for trajectory tracking of a class of underactuated mechanical control-affine systems is developed. In the developed control law, the fact that for underactuated systems, the actuated coordinates together with the corresponding generalized velocities can be considered as generalized inputs for the unactuated dynamics plays the main role. Using the developed control method, both actuated and unactuated coordinates of the system are able to follow slowly time-varying prescribed trajectories on average. The developed control method is applied for altitude control of flapping wing micro-air vehicles by considering the sweeping (flapping) angle of the wings as the inputs. Using the feathering (pitch) angles of the wings as additional inputs, and using non-symmetric flapping, the control method is then extended for three-dimensional flight control of flapping wing micro-air vehicles. / Ph. D.

Perennial weed creeping thistle and couch-grass were controlled for tree year period in Prepychy village (Rychnov nad Kneznou district). Stubble breaking had cardinal effect on regeneration of hypogenous vegetative organs both wedd and endorsed their appearance. Following ploughing and ground reproduction before seeding didn´t control these weed. In chemical control section was tested an effectiveness of 22 herbicides. Creeping thistle showed the highest sensitivity against the majority of herbicides in growth phase F4 (stalk height 20 cm). Results of experiments showed an importance of application a.i. glyphosate in perennial weed control system. In winter wheat vegetation showed herbicides Husar and Lontrel 300 the highest effect against creeping thistle. Broad-leaved crops give a possibility to use graminicides against couch-grass. Graminicides Fusilade Forte 150 EC and Gallant Super shown the highest effect against couch-grass.

3D printing technology, which has its origins in rapid prototyping, is increasingly used to build functional devices. Although 3D printing technology has been well developed for thermoplastic polymers and metals, it is still in the research phase for soft polymeric materials such as silicones. Silicones are an industrially vital polymer characterized by a broad spectrum of chemical and physical properties for several smart applications, including on skin printing, smart sensors, multigradient material, and soft actuators. Extrusion-based multimaterial printing is one of the 3D printing techniques that have been adapted due to its compatibility to process silicone-based materials for constructing various functional devices. However, there are several challenges such as achieving on the fly mixing at low Reynolds numbers regime, achieving fast switching while using Newtonian/non-Newtonian inks, and achieving multimaterial printing on nonplanar surfaces. The development of suitable and robust printheads that are able to tackle those challenges can expand the application of this technology to a wide range of fields. In this thesis, several deposition-controlled printhead designs have been created for 3D printing multifunctional devices using an understanding of microfluidics. The established printhead can be controlled to formulate different multigradient structures through on the fly mixing during the material printing. Moreover, the developed printhead can be adapted to print multi viscous inks with high switching rates up to 50 Hz. Through the developed system, the printhead was able to track topologies in real-time, allowing objects to be printed over complex substrates. These new capabilities were applied to fabricate functional structures in order to demonstrate the potential of the developed printhead approaches that can be used in various applications, including smart sensors, soft robotics and multigradient objects. / Thesis / Doctor of Philosophy (PhD) / 3D printing techniques, such as extrusion-based multimaterial printing, have recently been utilized to process silicones due to their versatility in different smart applications, including multigradient material and soft actuators. Although it represents significant progress, there are still several challenges, including the proper mixing during printing with a laminar flow regime, the fast switching between different inks, and the printing over complex topographies. Therefore, various printhead designs have been developed in this thesis to tackle these challenges. In particular, a mixer printhead has been designed to allow mixing during printing for building multigradient objects. Also, a scalable printhead has been developed to allow fast switching for creating pixelated structures. Finally, a simple mechanical system has achieved multimaterial printing over various nonplanar surfaces. To the best of the author's knowledge, the developed printheads can be used in many fields, such as soft robotics and smart devices.

Made available in DSpace on 2015-03-26T13:40:01Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1204733 bytes, checksum: b4e6a304ba4ac7b2d9690d080936613d (MD5) Previous issue date: 2013-07-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The interference of the species Urochloa brizantha and Urochloa decumbens can cause irreversible damages to eucalypts plants. With this, it is necessary to handle them correctly in order to favor the growth of the culture. In this study, the objective was to evaluate the silvicultural and physiological characteristics, the levels of nutrients in the leaves, and the microbiological activity of the eucalypts rhizosphere, submitted to methods of control of the Urochloa species. The experiment was conducted in a protected environment, used a randomized outline with five repetitions, in a factorial scheme (5 x 2) +1, with five groups of Urochloa spp (no control; chemical control maintain the waste of weeds in the pot; chemical control removing the waste of weeds from the pot; mechanical control maintaining the weed waste in the pot; and mechanical control removing the weed waste from the pot), two species of weed plants (U. brizantha e U. decumbens) and a control (eucalypts without a weed plant). The experimental units had pots with 110 dm3 with one plant of eucalypts and 10 plants of U. brizantha or of U. decumbens, 50 plants -2. The growth of eucalypts was measured every 10 days using the height of the plant (cm) and root collar diameter. At the days 18, 38, 48 and 105, after the transplanting (DAT), the photosynthetic level, the transpiration level, the consumption of CO2, the stomatal conductance, the efficiency in the use of water, the concentration of internal CO2, the ratio between the concentrations of internal carbon and of atmospheric carbon, and the leaf temperature were evaluated. After 107 DAT, leaves, stem, branches and the root system of the eucalyptus were collected separately for the determination of dry matter and of the foliar area. Foliar samples of the eucalypts were also collected for the ascertainment of the level of nutrients and ground rhizosphere for the ascertainment of the microbiological activity. The results were submitted to the Dunnett test, with a 5% probability and only the management had significant relevance for the silvicultural, physiological, basal respiratory level, and the microbiological biomass carbon variables. The eucalypts plants in competition presented stagnation in the root collar diameter at 20 DAT and decreasing photosynthetic levels at 48 DAT, indicating the necessity of controls, made at 50 DAT. The height of the plants was not affected by the presence of the competitor species until the control, however, after the control the treatments where there was chemical control (keeping or removing the residues of weeds of the species Urochloa in/from the pot) and in the treatment where there was mechanical control keeping the weed residues of Urochloa spp. in the pot, the eucalypts presented greater increase in height, deferring from the other arrangements and the control. Living with the species Urochloa for 107 days affected the root collar diameter, influencing negatively in the dry matter of the eucalypts. The same was observed for the foliar area, photosynthetic level and foliar levels of nitrogen, manganese and iron of the eucalypts plants. In the presence of U. brizantha, the eucalypts presented smaller foliar levels of phosphorus for the chemical management, keeping or removing the weed residues of the competitor agents, and higher foliar levels of copper in the chemical treatment, keeping the weed residues of Urochloa spp. in the pot. There was no significant impact in the microbiota of the soil because of the plants. One concludes that, the presence of the species Urochloa, for 107 days, affects the silvicultural and physiological variables negatively. A difference between chemical and mechanical management of the plants was not observed, maintaining or not weed residue in the pot. This shows that all of the controls were effective and did not cause disturbances to micro-organisms of the eucalypts. / A interferência das espécies Urochloa brizantha e Urochloa decumbens pode causar danos irreversíveis as plantas de eucalipto. Com isso, torna-se necessário manejá-las corretamente a fim de favorecer crescimento da cultura. Neste trabalho, objetivou-se avaliar o crescimento inicial, as características silviculturais, as características fisiológicas, os teores de nutrientes nas folhas e a atividade microbiológica da rizosfera do eucalipto submetido a métodos de controle das espécies de Urochloa. O experimento foi conduzido em ambiente protegido, em DBC com cinco repetições, no esquema fatorial (5 x 2) +1, sendo cinco manejos de Urochloa spp. (sem controle; controle químico mantendo os resíduos da capina no vaso; controle químico retirando os resíduos da capina do vaso; controle mecânico mantendo os resíduos da capina no vaso e controle mecânico retirando os resíduos da capina do vaso), duas espécies de plantas daninhas (U. brizantha e U. decumbens) e uma testemunha (eucalipto isento de planta daninha). As unidades experimentais consistiram de vasos de 110 dm3 com uma planta de eucalipto e dez plantas de U. brizantha ou de U. decumbens, 50 plantas m-2. O crescimento do eucalipto foi mensurado a cada 10 dias por meio da altura de planta (cm) e do diâmetro do coleto (mm). Aos 18, 38, 48 e 105 dias após o transplantio (DAT) avaliou-se a taxa fotossintética, a taxa transpiratória, o consumo de CO2, a condutância estomática, a eficiência do uso de água, a concentração de CO2 interno, a razão entre as concentrações de carbono interno e de carbono atmosférico e a temperatura foliar. Após 107 DAT, coletaram-se separadamente folhas, caule, ramos e o sistema radicular do eucalipto para a determinação da matéria seca e área foliar. Amostras foliares do eucalipto também foram coletadas para a determinação dos teores de nutrientes e solo rizosférico para determinação da atividade microbiológica. Os resultados foram submetidos ao teste Dunnett, a 5% de probabilidade, sendo que apenas o manejo apresentou significância para as variáveis silviculturais, fisiológicas, taxa respiratória basal e o carbono da biomassa microbiana. Para a análise de nutrientes e quociente metabólico observou-se interação significativa para manejos e espécies. As plantas de eucalipto em competição apresentaram estagnação do diâmetro do coleto aos 20 DAT e decréscimos nas taxas fotossintéticas aos 48 DAT, indicando a necessidade da realização dos controles, que foram realizados aos 50 DAT. A altura de plantas não foi afetada pela presença das espécies competidoras até o momento do controle controle, porém, após o mesmo os tratamentos onde houve controle químico (mantendo ou retirando os resíduos da capina das espécies de Urochloa do vaso) e no tratamento onde houve controle mecânico mantendo os resíduos da capina das Urochloa spp. no vaso, o eucalipto apresentou maior ganho em altura, diferindo dos demais manejos e da testemunha. A convivência das espécies de Urochloa por 107 dias afetou o diâmetro do coleto, influenciando negativamente na matéria seca do eucalipto. O mesmo foi observado para a aérea foliar e taxa fotossintética e teores foliares de nitrogênio, manganês e ferro das plantas de eucalipto. Na presença de U. brizantha, o eucalipto apresentou menores teores foliares de fósforo para os manejos químicos, mantendo ou retirando os resíduos da capina dos agentes competidores, e maiores teores foliares de cobre no tratamento químico, mantendo os resíduos da capina de Urochloa spp. no vaso. Não houve impacto significativo na atividade da microbiota do solo pelos manejos. Conclui-se que a presença das espécies de Urochloa, por 107 dias, afetou negativamente as variáveis silviculturais e fisiológicas. Não observou-se diferenças entre os manejos químico e mecânico, mantendo ou retirando os resíduos da capina das espécies de Urochloa, evidenciando que todos os controles se mostraram eficientes e não causaram distúrbios aos micro-organismos da rizosfera do eucalipto.

Begreppet gaseller har fått en allt större betydelse sedan det introducerades av Birch år 1979. Gasellföretags utmaning är att de arbetar under en hög tillväxt. Att ständigt bibehålla en snabb tillväxt och hög prestanda blir allt svårare när det sker i en oförutsebar miljö. Beslut angående organisatoriska förändringar måste tas i en snabbare takt än i andra företag. Eftersom gasellföretag skiljer sig från andra företag innebär det även att organisationens hantering av styrsystem kan vara annorlunda. Syftet med uppsatsen är att studera gasellföretags användning av formella styrsystem. Med vår studie vill vi undersöka om gasellföretags styrsystem har en mer organisk eller mekanisk karaktär. Vi vill även belysa vilken typ av tillväxt som gasellföretag har.Vi har använt en kvalitativ forskningsmetod med en abduktiv forskningsansats. Specifika urval gjordes angående teori, företag samt intervjudeltagare. Primärdatan som användes var besöksintervjuer samt skypeintervjuer med gasellföretag, forskningsfrågorna operationaliserades. Uppsatsen är utformad så att kvalitetsmåttens validitet och reliabilitet är goda. Hänsyn till forskningsetik togs för att uppfylla etikkraven. Vårt utfall blev att majoriteten av studerade gasellföretag planerade sina strategier, vilket går emot en teori att företag i oförutsebara miljöer inte använder planerade strategier. Vi anser att det inte är företags handlingsplan som skapar tillväxt utan företags platta struktur med horisontell kommunikation och god företagskultur. Fem av sex gasellföretag använder budget samt alla använder rullande prognoser, vilket innebär att gasellföretag utformar formella styrsystem trots en hög tillväxt och oförutsebara miljöer. Karaktären av budgeten var skiljaktig, både organisk och mekanisk. Gasellföretag växer främst genom organisk tillväxt och inte genom en förvärvad tillväxt. Någon exakt slutsats angående var gasellföretag befinner sig i tillväxtens fem faser kan inte fastslås. Det vi fann var att ingen av de studerade gasellföretagen befann sig högre än tredje fasen. / The concept of gazelle has become increasingly important since it was introduced by Birch in 1979. The largest challenge for a gazelle company is that they are working under high growth. Constantly maintaining a rapid growth and high performance becomes increasingly difficult when it happens in an unforeseeable environment. Decisions regarding organizational changes must be taken at a faster pace than within other companies. Because gazelle-companies often varies from other companies, their organizational control systems may also differ. The purpose of the essay is to study the use of formal control systems by gazelle-companies. We want to investigate whether the gazelle-companies control systems have a more organic or mechanical character. We also want to highlight what kind of growth a gazelle-company has. We have used a qualitative research method with an abductive research approach. Specific selection was made regarding theory, company and interviewee. The primary data used was physical interviews and skype interviews with gazelle-companies, the research questions were operationalized. The essay is designed so that the quality measurements validity and reliability are correct. Consideration of research ethics was taken to fulfil the ethics requirement. The majority of our researched gazelle-companies plan their strategies, which is the opposite to the theory that companies in unforeseeable environments don’t use planned strategies. We believe that it’s not the companies action plan that creates growth, instead it is because these companies have a flat structure with horizontal communication and a good corporate culture. Five out of six gazelle-companies use a budget and all companies use rolling forecasts, which means that gazelle-companies design formal control systems despite high growth and unforeseeable environments. The character of the budget was both organic and mechanical. Gazelle-companies grow mainly through organic growth and not through acquired growth. The exact conclusion about where a gazellecompany is in the five phases of growth can’t be determined. We found that none of the gazelles where higher than the third phase.

Disturbance is one of most important selective factor causing removal of plant biomass. Man-made habitats are characterized by strong and unpredictable disturbances, providing bare soil surface colonized by plants with short life cycle. Populations of the short-lived plants are, however, vulnerable to the strong disturbance removing all stem parts with reserve axillary meristems in the case it occurs before plant flowering and fruiting. Nevertheless, 2 % of annual and 14 % of biennial plants are able to overcome meristem limitation by adventititous sprouting from hypocotyle or/and roots. This thesis is composed of four original studies describing the occurrence of adventitious sprouting in natural populations of 22 monocarpic weeds of Central Europe and one species in Indonesia. The studied phenomenon was analyzed in relation to various environmental factors and plant traits in the field and in experimental conditions.