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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.
1

Controle do desenvolvimento das hastes no capim Tanzânia: um desafio. / Stems production control on Tanzania grass: a challenge.

Santos, Patricia Menezes 22 March 2002 (has links)
O capim Tanzânia (Panicum maximum Jacq. cv. Tanzânia) tem sido amplamente utilizado em áreas de pastagem no Brasil. O aumento da participação das hastes na produção, no entanto, têm efeito negativo sobre a qualidade da forragem e a eficiência do pastejo, principalmente durante o florescimento. O objetivo deste trabalho foi gerar informações sobre o perfilhamento e a dinâmica interna de nitrogênio, de modo a permitir a proposição de estratégias de manejo visando o controle do desenvolvimento das hastes. Para isso foram realizados dois experimentos. O primeiro em área de capim Tanzânia irrigado na ESALQ/USP, em Piracicaba-SP, entre outubro/1999 e junho/2000. O delineamento experimental foi de blocos ao acaso com três tratamentos (intensidade de pastejo alta, média e baixa) e quatro repetições. Foram avaliados: número; peso; porcentagem de folhas; participação na produção total, de folhas e de hastes; e a DIVMO das gerações de perfilhos. O segundo experimento foi realizado em câmaras de crescimento no MLURI, em Aberdeen-Escócia. O capim Tanzânia foi cultivado em vasos, recebendo solução nutritiva completa até que a 7a folha estivesse expandida. A partir de então, passou a receber solução nutritiva semelhante, alguns com 15N e outros com zero N. As plantas foram coletadas no momento da completa expansão das folhas 7, 8 e 9, e separadas em suas partes constituintes. As amostras foram secadas, pesadas, moídas e depois analisadas quanto às concentrações de N total e de 15N, utilizando-se espectrômetro de massa de fluxo contínuo. Nenhuma geração de perfilhos destacou-se em termos de participação na massa de forragem total, não sendo possível programar o manejo do capim Tanzânia com base nas caraterísticas de uma única geração. A porcentagem de folhas dependeu, principalmente, do estádio de desenvolvimento do capim e do ciclo de pastejo. Não é possível, portanto, controlar o desenvolvimento das hastes através de cortes estratégicos que eliminem determinadas gerações de perfilhos. A participação das gerações de perfilhos na produção de hastes dependeu da intensidade de pastejo, sendo a participação das gerações mais novas maior no pastejo mais intenso. A DIVMO das gerações diminuiu com a idade e, de modo geral, foi maior nas áreas submetidas a alta intensidade de pastejo. Estratégias de manejo que promovam maior renovação de perfilhos a partir de fevereiro parecem boas alternativas para reduzir os efeitos negativos do florescimento. No entanto, é preciso observar suas conseqüências sobre a produção animal e a perenidade do pasto. No capim Tanzânia, os principais drenos de nitrogênio foram as folhas em expansão, seguidas dos perfilhos laterais e raízes. As folhas expandidas mais novas representaram a principal fonte de nitrogênio para mobilização. A alocação da maior parte do nitrogênio em órgãos de fácil acesso à colheita demonstra a necessidade de estudos sobre a dinâmica de nitrogênio em plantas submetidas a desfolha. Este processo pode limitar a adoção de práticas de manejo que promovam maior renovação na população de perfilhos. A absorção radicular foi a principal fonte de N, demonstrando a necessidade de estudos sobre o sistema radicular e a dinâmica de nitrogênio no sistema solo-planta. / Tanzânia grass (Panicum maximum Jacq. cv. Tanzânia) is widely used for grazing in Brazil. The increase in stem production, mainly during flowering, has a negative impact over forage quality and grazing efficiency. The aim of this work was to study tillering and nitrogen dynamics in order to propose management alternatives for the control of stem production. Two experiments were done. The first was on an irrigated Tanzânia grass pasture at ESALQ/USP, in Piracicaba-SP, between October/1999 and June/2000. The experiment was on a complete block design with three treatments (high, medium and low grazing intensities) and four replicates. Tiller cohorts were identified by coloured plastic coated wire. The number weight leaf percentage contribution to total production and to leaf and stem production, and IVOMD of each cohort were evaluated throughout the experiment. The second experiment was conducted on the MLURI, in Aberdeen-Scotland. Tanzânia grass plants were grown in sand culture in controlled environment rooms and supplied with a complete nutrient solution until the 7th leaf was fully expanded. From then on, the plants received either an identical solution containing 15N or a complete nutrient solution containing zero N. They were destructively harvested and separated into various components when the 7th, 8th and 9th leaves were fully expanded. All plant material was weighted after oven drying at 65oC, and then ball-milled prior to analysis. The total N and 15N concentrations of the samples were determined using a continuous flow mass spectrometer. No tiller cohort was identified as responsible for most of dry mass production, so it is not possible to base Tanzânia grass management on the characteristics of a single cohort. The percentage of leaves was mainly related to plant development stage and grazing cycle. The contribution of tiller cohorts to stem production was influenced by grazing intensities: the participation of the youngest cohorts was higher on heavily grazed areas. The IVOMD of tiller cohorts decreased over the grazing cycles and was higher on heavily grazed areas. Obtaining a higher tiller turnover through management practices seems to be the best way to reduce the negative effects of flowering over forage quality and grazing efficiency. The consequences of these management strategies over pasture persistence and animal production need to be established. The main sinks of nitrogen on Tanzânia grass were expanding leaves, followed by side tillers and roots. The youngest fully expanded leaves were the main sources of nitrogen for mobilisation. As most nitrogen is allocated to plant compartments easily harvested by grazing, studies about nitrogen dynamics on defoliated plants are necessary to verify these effects over pasture regrowth and persistence. This process may limit the adoption of management strategies that increase tiller turnover. Root uptake was the main source of nitrogen for new growth, indicating the necessity of more studies on root development and nitrogen dynamics on soil-plant system.
2

Controle do desenvolvimento das hastes no capim Tanzânia: um desafio. / Stems production control on Tanzania grass: a challenge.

Patricia Menezes Santos 22 March 2002 (has links)
O capim Tanzânia (Panicum maximum Jacq. cv. Tanzânia) tem sido amplamente utilizado em áreas de pastagem no Brasil. O aumento da participação das hastes na produção, no entanto, têm efeito negativo sobre a qualidade da forragem e a eficiência do pastejo, principalmente durante o florescimento. O objetivo deste trabalho foi gerar informações sobre o perfilhamento e a dinâmica interna de nitrogênio, de modo a permitir a proposição de estratégias de manejo visando o controle do desenvolvimento das hastes. Para isso foram realizados dois experimentos. O primeiro em área de capim Tanzânia irrigado na ESALQ/USP, em Piracicaba-SP, entre outubro/1999 e junho/2000. O delineamento experimental foi de blocos ao acaso com três tratamentos (intensidade de pastejo alta, média e baixa) e quatro repetições. Foram avaliados: número; peso; porcentagem de folhas; participação na produção total, de folhas e de hastes; e a DIVMO das gerações de perfilhos. O segundo experimento foi realizado em câmaras de crescimento no MLURI, em Aberdeen-Escócia. O capim Tanzânia foi cultivado em vasos, recebendo solução nutritiva completa até que a 7a folha estivesse expandida. A partir de então, passou a receber solução nutritiva semelhante, alguns com 15N e outros com zero N. As plantas foram coletadas no momento da completa expansão das folhas 7, 8 e 9, e separadas em suas partes constituintes. As amostras foram secadas, pesadas, moídas e depois analisadas quanto às concentrações de N total e de 15N, utilizando-se espectrômetro de massa de fluxo contínuo. Nenhuma geração de perfilhos destacou-se em termos de participação na massa de forragem total, não sendo possível programar o manejo do capim Tanzânia com base nas caraterísticas de uma única geração. A porcentagem de folhas dependeu, principalmente, do estádio de desenvolvimento do capim e do ciclo de pastejo. Não é possível, portanto, controlar o desenvolvimento das hastes através de cortes estratégicos que eliminem determinadas gerações de perfilhos. A participação das gerações de perfilhos na produção de hastes dependeu da intensidade de pastejo, sendo a participação das gerações mais novas maior no pastejo mais intenso. A DIVMO das gerações diminuiu com a idade e, de modo geral, foi maior nas áreas submetidas a alta intensidade de pastejo. Estratégias de manejo que promovam maior renovação de perfilhos a partir de fevereiro parecem boas alternativas para reduzir os efeitos negativos do florescimento. No entanto, é preciso observar suas conseqüências sobre a produção animal e a perenidade do pasto. No capim Tanzânia, os principais drenos de nitrogênio foram as folhas em expansão, seguidas dos perfilhos laterais e raízes. As folhas expandidas mais novas representaram a principal fonte de nitrogênio para mobilização. A alocação da maior parte do nitrogênio em órgãos de fácil acesso à colheita demonstra a necessidade de estudos sobre a dinâmica de nitrogênio em plantas submetidas a desfolha. Este processo pode limitar a adoção de práticas de manejo que promovam maior renovação na população de perfilhos. A absorção radicular foi a principal fonte de N, demonstrando a necessidade de estudos sobre o sistema radicular e a dinâmica de nitrogênio no sistema solo-planta. / Tanzânia grass (Panicum maximum Jacq. cv. Tanzânia) is widely used for grazing in Brazil. The increase in stem production, mainly during flowering, has a negative impact over forage quality and grazing efficiency. The aim of this work was to study tillering and nitrogen dynamics in order to propose management alternatives for the control of stem production. Two experiments were done. The first was on an irrigated Tanzânia grass pasture at ESALQ/USP, in Piracicaba-SP, between October/1999 and June/2000. The experiment was on a complete block design with three treatments (high, medium and low grazing intensities) and four replicates. Tiller cohorts were identified by coloured plastic coated wire. The number weight leaf percentage contribution to total production and to leaf and stem production, and IVOMD of each cohort were evaluated throughout the experiment. The second experiment was conducted on the MLURI, in Aberdeen-Scotland. Tanzânia grass plants were grown in sand culture in controlled environment rooms and supplied with a complete nutrient solution until the 7th leaf was fully expanded. From then on, the plants received either an identical solution containing 15N or a complete nutrient solution containing zero N. They were destructively harvested and separated into various components when the 7th, 8th and 9th leaves were fully expanded. All plant material was weighted after oven drying at 65oC, and then ball-milled prior to analysis. The total N and 15N concentrations of the samples were determined using a continuous flow mass spectrometer. No tiller cohort was identified as responsible for most of dry mass production, so it is not possible to base Tanzânia grass management on the characteristics of a single cohort. The percentage of leaves was mainly related to plant development stage and grazing cycle. The contribution of tiller cohorts to stem production was influenced by grazing intensities: the participation of the youngest cohorts was higher on heavily grazed areas. The IVOMD of tiller cohorts decreased over the grazing cycles and was higher on heavily grazed areas. Obtaining a higher tiller turnover through management practices seems to be the best way to reduce the negative effects of flowering over forage quality and grazing efficiency. The consequences of these management strategies over pasture persistence and animal production need to be established. The main sinks of nitrogen on Tanzânia grass were expanding leaves, followed by side tillers and roots. The youngest fully expanded leaves were the main sources of nitrogen for mobilisation. As most nitrogen is allocated to plant compartments easily harvested by grazing, studies about nitrogen dynamics on defoliated plants are necessary to verify these effects over pasture regrowth and persistence. This process may limit the adoption of management strategies that increase tiller turnover. Root uptake was the main source of nitrogen for new growth, indicating the necessity of more studies on root development and nitrogen dynamics on soil-plant system.
3

GPS mapování geomorfologicky zajímavých lokalit Novohradských hor / GPS mapping of geomorphologicaly interesting localities in the Novohradské Mountains

KADUBEC, Josef January 2008 (has links)
Novohradské Mountains are an unique area, that it has been little searched, not only in term of geomorphology. The aim of this diploma thesis is to map geomorphologicly the most interesting localities by the help of GPS technology. Further on the basis of mapping to create the detailed geomorphologic plans in the application ArcGIS 9.1. and to write a text, that describes single forms of the relief on the chosen localities. There is also brief physical-geographic characteristic of the monitored area. The GPS mapping was in progress in the years 2006 and 2007. This work was particularly supported by grant AVČR KJB 300460501.
4

APPLYING UAVS TO SUPPORT THE SAFETY IN AUTONOMOUS OPERATED OPEN SURFACE MINES

Hamren, Rasmus January 2021 (has links)
Unmanned aerial vehicle (UAV) is an expanding interest in numerous industries for various applications. Increasing development of UAVs is happening worldwide, where various sensor attachments and functions are being added. The multi-function UAV can be used within areas where they have not been managed before. Because of their accessibility, cheap purchase, and easy-to-use, they replace expensive systems such as helicopters- and airplane-surveillance. UAV are also being applied into surveillance, combing object detection to video-surveillance and mobility to finding an object from the air without interfering with vehicles or humans ground. In this thesis, we solve the problem of using UAV on autonomous sites, finding an object and critical situation, support autonomous site operators with an extra safety layer from UAVs camera. After finding an object on such a site, uses GPS-coordinates from the UAV to see and place the detected object on the site onto a gridmap, leaving a coordinate-map to the operator to see where the objects are and see if the critical situation can occur. Directly under the object detection, reporting critical situations can be done because of safety-distance-circle leaving warnings if objects come to close to each other. However, the system itself only supports the operator with extra safety and warnings, leaving the operator with the choice of pressing emergency stop or not. Object detection uses You only look once (YOLO) as main object detection Neural Network (NN), mixed with edge-detection for gaining accuracy during bird-eye-views and motion-detection for supporting finding all object that is moving on-site, even if UAV cannot find all the objects on site. Result proofs that the UAV-surveillance on autonomous site is an excellent way to add extra safety on-site if the operator is out of focus or finding objects on-site before startup since the operator can fly the UAV around the site, leaving an extra-safety-layer of finding humans on-site before startup. Also, moving the UAV to a specific position, where extra safety is needed, informing the operator to limit autonomous vehicles speed around that area because of humans operation on site. The use of single object detection limits the effects but gathered object detection methods lead to a promising result while printing those objects onto a global positions system (GPS) map has proposed a new field to study. It leaves the operator with a viewable interface outside of object detection libraries.

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