Avaliação de sensor capacitivo para o monitoramento do teor de água do solo

Este trabalho teve como objetivo avaliar sensores capacitivos desenvolvidos para monitorar o teor de água do solo. Os sensores foram submetidos a testes para avaliar o efeito da temperatura, o tempo de resposta, obter a equação de calibração e determinar a sua sensibilidade. Foram analisados em diferentes situações (solo, água e ar) e temperaturas (25 ºC; 20 ºC; 15 ºC; 10 ºC; 5º C e 0 ºC). A calibração foi efetuada com um dos sensores capacitivos instalado em uma coluna de solo (indeformada) contida em um tubo de PVC (0,015066 m³) e suspensa em um dos lados de uma balança de braços. Na outra extremidade da balança, havia uma célula de carga conectada a um sistema de aquisição de dados. Os resultados indicaram redução na frequência do sensor capacitivo com o aumento da temperatura. O sensor capacitivo apresentou alta velocidade de resposta (menos de um segundo) ao imergi-lo na água e às variações da quantidade de água na amostra de solo e detectou as mudanças de perda de água pela coluna de solo no decorrer deste experimento, apresentando maior sensibilidade à medida que se diminui o conteúdo de água no solo. Portanto, o sensor capacitivo pode ser utilizado para determinar o teor de água do solo de forma adequada.

Design and development of the architecture of an agricultural mobile robot

Parameters such as tolerance, scale and agility utilized in data sampling for using in Precision Agriculture required an expressive number of researches and development of techniques and instruments for automation. It is highlighted the employment of methodologies in remote sensing used in coupled to a Geographic Information System (GIS), adapted or developed for agricultural use. Aiming this, the application of Agricultural Mobile Robots is a strong tendency, mainly in the European Union, the USA and Japan. In Brazil, researches are necessary for the development of robotics platforms, serving as a basis for semi-autonomous and autonomous navigation systems. The aim of this work is to describe the project of an experimental platform for data acquisition in field for the study of the spatial variability and development of agricultural robotics technologies to operate in agricultural environments. The proposal is based on a systematization of scientific work to choose the design parameters utilized for the construction of the model. The kinematic study of the mechanical structure was made by the virtual prototyping process, based on modeling and simulating of the tension applied in frame, using the.

Development of capacitive sensor for measuring soil water content

The irrigation management based on the monitoring of the soil water content allows for the minimization of the amount of water applied, making its use more efficient. Taking into account these aspects, in this work, a sensor for measuring the soil water content was developed to allow real time automation of irrigation systems. This way, problems affecting crop yielding such as irregularities in the time to turn on or turn off the pump, and excess or deficit of water can be solved. To develop the sensors were used stainless steel rods, resin, and insulating varnish. The sensors measuring circuit was based on a microcontroller, which gives its output signal in the digital format. The sensors were calibrated using soil of the type “Quartzarenic Neosoil”. A third order polynomial model was fitted to the experimental data between the values of water content corresponding to the field capacity and the wilting point to correlate the soil water content obtained by the oven standard method with those measured by the electronic circuit, with a coefficient of determination of 93.17%, and an accuracy in the measures of ±0.010 kg kg-1. Based on the results, it was concluded that the sensor and its implemented measuring circuit can be used in the automation process of irrigation systems.

Experimental evaluation of the performance of a wireless sensor network in agricultural environments

The aim of this study was to perform an experimental study to evaluate the proper operation distance between the nodes of a wireless sensor network available on the market for different agricultural crops (maize, physic nut, eucalyptus). The experimental data of the network performance offers to farmers and researchers information that might be useful to the sizing and project of the wireless sensor networks in similar situations to those studied. The evaluation showed that the separation of the nodes depends on the type of culture and it is a critical factor to ensure the feasibility of using WSN. In the configuration used, sending packets every 2 seconds, the battery life was about four days. Therefore, the autonomy may be increased with a longer interval of time between sending packets.

Seasonality of net radiation in two sub-basins of Paracatu by the use of modis sensor products

The net radiation (Rn) represents the main source of energy for physical and chemical processes that occur in the surface-atmosphere interface, and it is used for air and soil heating, water transfer, in the form of vapor from the surface to the atmosphere, and for the metabolism of plants, especially photosynthesis. If there is no record of net radiation in certain areas, the use of information is important to help determine it. Among them we can highlight those provided by remote sensing. In this context, this work aims to estimate the net radiation, with the use of products of MODIS sensor, in the sub-basins of Entre Ribeiros creek and Preto River, located between the Brazilian states of Goiás and Minas Gerais. The SEBAL (Surface Energy Balance Algorithm for Land) was used to obtain the Rn in four different days in the period of July to October, 2007. The Rn results obtained were consistent with others cited in the literature and are important because the orbital information can help determine the Rn in areas where there are not automatic weather stations to record the net radiation.

Uso de imagens do sensor orbital modis na estimação de datas do ciclo de desenvolvimento da cultura da soja para o estado do Paraná – Brasil

RESUMO O Estado do Paraná caracteriza-se por uma grande variabilidade de épocas de semeadura (DS) e, consequentemente, pelo desenvolvimento máximo vegetativo (DMDV), colheita (DC) e ciclo (CI) para a cultura da soja. O objetivo deste trabalho foi estimar essas datas para o período de primavera-verão do ano-safra de 2011/2012, por meio de séries temporais de imagens do Índice de Vegetação Realçado (do inglês Enhanced Vegetation Index - EVI) do sensor Modis (Moderate Resolution Imaging Spectroradiometer). Gerou-se um perfil espectrotemporal médio de EVI, considerando todos os pixels mapeados como soja dentro de cada município. Estes dados serviram de entrada no software Timesat para estimar os decêndios do ciclo da cultura (DS, DMDV, DC e CI) por municípios. Os resultados mostraram que existe grande variabilidade de datas de plantio em diferentes mesorregiões do Estado. Verificaram-se também divergências entre os resultados encontrados e os dados oficiais de DS e DC. A maior parte da semeadura (65,16%) esteve entre o terceiro decêndio de outubro e o primeiro decêndio de novembro. A maior parte da área de soja do Estado do Paraná (65,46%) teve seu DMDV em janeiro e colheita em março (53,92%).

Virtual Battlespace 2 Panssarikoulun opetuksessa : tapaustutkimus sotilaspedagogiikan näkökulmasta

Tutkielmani tavoitteena oli tutkia tapauksena Bohemia Interactive Simulationsin valmistaman Virtual Battlespace 2 (VBS2) -tietokonepelisimulaattorin käyttöönottoa Panssariprikaatin Panssarikoulun varusmieskoulutuksessa. Tutkimuskysymysten avulla oli tarkoituksena selvittää, mitkä tekijät ja tapahtumat vaikuttivat siihen, että VBS2 otettiin käyttöön, minkälaisin perustein koulutus suunniteltiin ja järjestelmän käyttö varusmieskoulutuksessa käynnistettiin. Lisäksi ajatuksena oli aineiston mahdollistamissa puitteissa tutkia VBS2:n käytöstä tähän mennessä kertyneitä kokemuksia kouluttajien näkökulmasta, tavoitteena tuottaa myös perustietoa tulevaisuuden VBS2-koulutuksen suunnittelua ja toteuttamista varten. Tutkimusmenetelmänä oli tapaustutkimus, jonka aineisto kerättiin toteuttamalla teemahaastatteluita. Tutkimusta varten haastateltiin kahta VBS2-järjestelmää ensimmäisenä varusmieskoulutuksessa käyttänyttä kouluttajaa. Haastatteluaineisto käsiteltiin aineistolähtöisen sisällönanalyysin menetelmin. Tuloksia tarkasteltiin sotilaspedagogiikan näkökulmasta ja suhteessa oppimisympäristöjen sekä oppimisprosessin suunnittelun teorioihin. Tutkielma rakentuu johdannosta, menetelmäluvusta, yhdistetystä teoria- ja tulosluvusta sekä johtopäätös- ja pohdintaluvusta. Tutkimuksen tuloksina ilmeni, että Virtual Battlespace 2:n käyttöönotto Panssarikoulussa oli aktiivisten ja innovatiivisten henkilöiden aikaansaannosta, jossa spontaanin, ennakkoluulottoman ja opetuksen laadun kehittämiseen tähtäävän kokeilun myötä otettiin käyttöön uudenlainen koulutusväline. Samalla saatiin aikaan myönteisiä oppimistuloksia ja kiinnostavia muutoksia yhden joukkoyksikön koulutuskulttuuriin ja totunnaisiin koulutuksen käytäntöihin. VBS2:n käyttöön liittyviä keskeisiä teemoja ovat oppimisprosessin kokonaisvaltainen hallinta, eli VBS2-koulutuksen huolellinen suunnittelu ja integrointi osaksi muuta koulutusta, koulutustapahtumien valmistelujen ja kouluttajien ammattitaidon merkitys, koulutustapahtumien johtamisen paikoin muusta sotilaskoulutuksesta poikkeavat käytännöt sekä VBS2:n aikaansaaman oppimisen ymmärtäminen. Kouluttajien kokemusten perusteella VBS2 on avoin oppimisympäristö, joka ei korvaa mitään olemassa olevista koulutusmuodoista, mutta täydentää niitä tehokkaasti tarjoten uudenlaisia ulottuvuuksia sotilaskoulutukseen. Sen avulla voidaan tehokkaasti kehittää erityisesti sotilaan henkistä ja sosiaalista toimintakykyä sekä siirtää koulutuksen painopistettä soveltaviin maastoharjoituksiin. Tutkielma avaa näkökulmia VBS2:n ja muiden virtuaalisten oppimisympäristöjen pedagogiselle pohtimiselle ja tuleville aiheeseen syventyville tutkimuksille. Lisäksi se herättää keskustelua varusmieskoulutuksemme parhaista käytänteistä ja kehitystrendeistä.

Realidade virtual e robótica em cirurgia: aonde chegamos e para onde vamos?

Minimally Invasive Surgery, Telesurgery, Robotics and Virtual Reality represent the technological frontiers that have revolutionized operating practices nowadays. These new technologies aim at improving the quality of assistance offered to patients; thus, they demand from the medical staff more effective measures as far as scientific research, training and expenditure of time and financial resources are concerned. In the past, surgeons have led several medical revolutions, such as the use of antiseptic surgical methods by Semelweiss, the use of anesthesia by Warren, antibiotic therapy, the transplants and the onset of the minimally invasive surgery by Mouret and Perissat. The objective of this article is to present the outreach of this new technology which comprises minimal access, computing, robotics and teletransmission. We have concluded that the new technologies developed in the medical field in the last decades, will offer new options and challenges for the treatment of the surgical patient, leading the scientific knowledge to a new era, the one of the virtual environment.

Value co-creation through virtual community participation

Consumers create a great deal of content in the Internet. As they do not get a monetary compensation for doing so, it seems apparent that other types of reward are derived from giving up one's time and other resources. The purpose of this study is to describe value creation and user participation in a virtual community. It can be broken down into three research questions. 1. What is the value creation logic of a virtual community? 2. What value is perceived by virtual community users? 3. What is the association between value perceived by virtual community users and their participation in a community? The study employs the discussion on value co-creation as well as perspectives on the notion of value for consumers to create a theoretical framework for value creation. To understand value creation in the context of virtual communities and to create a theoretical framework for user participation, existing literature and research on virtual communities is discussed. The empirical part of the study employs quantitative methodology to analyze data collected by sending a survey questionnaire to the users of a Finnish wellbeing-based virtual community. The results indicate that virtual community users perceive self-development, enjoyment, reputation-building and community commitment value when using the service and that value perceptions are associated with community participation. Moreover, it was found that different types of value are associated with different forms of participation. Based on the findings, it is suggested that the four types of value make up a considerable share of value for virtual community users. Moreover, as the results indicate that different value types are associated with different forms of participation, it suggested that virtual community organizers consider what forms of participation they want to promote and design their virtual communities to support creation of the different types of value accordingly.

Heat flux measurement inside internal combustion engine with gradient heat flux sensor.

This master’s thesis is devoted to study different heat flux measurement techniques such as differential temperature sensors, semi-infinite surface temperature methods, calorimetric sensors and gradient heat flux sensors. The possibility to use Gradient Heat Flux Sensors (GHFS) to measure heat flux in the combustion chamber of compression ignited reciprocating internal combustion engines was considered in more detail. A. Mityakov conducted an experiment, where Gradient Heat Flux Sensor was placed in four stroke diesel engine Indenor XL4D to measure heat flux in the combustion chamber. The results which were obtained from the experiment were compared with model’s numerical output. This model (a one – dimensional single zone model) was implemented with help of MathCAD and the result of this implementation is graph of heat flux in combustion chamber in relation to the crank angle. The values of heat flux throughout the cycle obtained with aid of heat flux sensor and theoretically were sufficiently similar, but not identical. Such deviation is rather common for this type of experiment.

Virtual technology and haptic interface solutions for design and control of mobile working machines

Commercially available haptic interfaces are usable for many purposes. However, as generic devices they are not the most suitable for the control of heavy duty mobile working machines like mining machines, container handling equipment and excavators. Alternative mechanical constructions for a haptic controller are presented and analysed. A virtual reality environment (VRE) was built to test the proposed haptic controller mechanisms. Verification of an electric motor emulating a hydraulic pump in the electro-hydraulic system of a mobile working machine is carried out. A real-time simulator using multi-body-dynamics based software with hardware-in-loop (HIL) setup was used for the tests. Recommendations for further development of a haptic controller and emulator electric motor are given.

Value Co-Creation Through Virtual Community environment, Case: Oma Olivia

The purpose of this thesis is to examine what elements of value co-creation create value for participants of Oma Olivia magazine through Olivia magazine’s virtual community environment. Furthermore the aim is to discover why readers take part in creating Oma Olivia in order to discover is Oma Olivia worth publishing in the future. The data is collected from secondary and primary sources by scanning the existing academic literature and by conducting interviews and surveys. The empirical results state that the hypothesis model created from the academic literature is statistically significant and the elements of value co- creation process create value for readers. Magazine publishing organization may want to consider publishing Oma Olivia also in the future due to its nature of creating value for customers.