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Este trabalho apresentada um estudo experimental do fenômeno de biestabilidade que ocorre na geometria simplificada de dois tubos dispostos lado a lado submetidos a um escoamento cruzado turbulento. Na análise consideram-se a condição de tubos fixos e com um grau de liberdade (rotacional), submetidos a diferentes números de Reynolds. A técnica experimental consiste na medição de flutuações de velocidade do escoamento através da anemometria de fio quente em canal aerodinâmico, na avaliação dos esforços do escoamento sobre os tubos com o uso de uma célula de carga e na visualização dos efeitos do fenômeno biestável sobre os tubos livres para rotacionar. Os dados obtidos da medição no canal são tratados com o uso de ferramentas estatísticas, espectrais e de ondaletas. Os resultados das visualizações do escoamento são apresentados através de imagens obtidas das filmagens realizadas com uma câmera digital. A investigação experimental consiste de ensaios de cilindros rígidos elasticamente montados e pivotados na base e posteriormente liberados para oscilar e/ou rotacionar em um eixo central aos dois tubos, submetidos ao escoamento perpendicular permanente de ar no canal Nos resultados experimentais observam-se a presença da biestabilidade e nota-se o comportamento não simultâneo deste fenômeno ao longo dos cilindros. A formação assimétrica das esteiras também é estudada e atribuída à interação entre os vórtices das esteiras, já que, inicialmente, o desprendimento dos vórtices atrás dos cilindros é simétrico. Na avaliação dos esforços por extensiometria, as etapas de condicionamento e aquisição do sinal foram elaboradas e os resultados de deformação mecânica apresentaram similaridade com o fenômeno observado na anemometria experimental. Para um número de Reynolds de 27635 encontrou-se uma força de 26,1 mN com um torque desenvolvido na célula de carga de 84,95Nmm. A técnica de visualização do fenômeno empregada corrobora a interpretação dos resultados obtidos através da técnica de anemometria de fio quente e extensiometria em canal aerodinâmico. / This paper presents an experimental study of the bistability phenomenon that occurs in the simplified geometry of two tubes arranged side by side submitted to a turbulent cross flow. In the analysis we consider the condition of fixed tubes and with a degree of freedom (rotational), submitted to different Reynolds numbers. The experimental technique consists in the measurement of velocity fluctuations through the aerodynamic channel with the hot wire anemometry technique, the evaluation of the stresses of the flow on the tubes with the use of a load cell and the visualization of the effects of the bistable phenomenon on the tubes free to rotate. The data obtained from the measurement in the channel are treated with the use of statistical, spectral and wavelet tools. The results of the flow visualizations are presented through images obtained with a high speed digital camera. The experimental investigation consists of tests of rigid cylinders mounted elastically and pivoted at the base and later released to oscillate and / or to rotate in a central axis to the two tubes, submitted to the flow of air in the channel In the experimental results we observe the presence of bistability and note the non-simultaneous behavior of the phenomenon along the cylinders. The asymmetric formation of the wakes is also studied and attributed to the interaction between the vortices from wakes behind the cylinders, since, initially, the wake detachments is symmetrical. In the evaluation of the forces by means of the extensiometry technique, the steps of conditioning and acquisition of the signal were elaborated and the results of mechanical deformation presented similarity with the phenomenon observed in the experimental anemometry. For a Reynolds number of 27635 a force of 26.1 mN was found with a torque developed in the load cell of 84.95 Nmm. The technique used for the visualization of the phenomenon corroborates the interpretation of the results obtained through hot wire anemometry and extensiometry in aerodynamic channel.

Neste trabalho foram desenvolvidos sistemas de aquisição portáteis de formato esférico, capazes de sensoriar forças de compressão e impacto ao longo dos três eixos cartesianos. Os instrumentos desenvolvidos foram utilizados em diferentes experimentos feitos em estabelecimentos de beneficiamento de frutas (packinghouses) durante o processo de pós-colheita a fim de verificar os danos mecânicos sofridos pelas mesmas. Os instrumentos são sistemas microcontrolados compostos por quarto sensores (acelerômetros, célula de carga, temperatura e umidade), memória Flash para o armazenamento dos dados, transceptor de rádio freqüência e uma porta de comunicações serial universal (USB). A coleta, apresentação e processamentos dos dados obtidos foram feitos por um software desenvolvido em ambiente C++ para o sistema operacional Windows. Fortes forças de compressão e impacto foram registradas, sugerindo a necessidade de mudanças no processo de seleção (mecânica e manual), empacotamento e transporte de frutas. Quatro protótipos diferentes foram desenvolvidos, dois com cabos e dois sem. Os dispositivos provaram ser úteis, funcionando como esperado e o seu projeto modular permite o desenvolvimento de diferentes instrumentos. Os resultados obtidos propiciaram pesquisas relativas aos danos sofridos por frutas durante o processo de pós-colheita. / In this work, spherical shape portable data acquisition systems that are capable of sensing compression and impact forces along the three Cartesian axes were developed. The developed instruments were utilized in several different experiments done in fruit packinghouses during the post harvest process in order to check the mechanical damages they suffer. They are microcontrolled systems composed by four sensors (accelerometers, load cell, temperature and humidity), Flash memory for data storage, radio frequency transceiver and a universal serial bus (USB) communication port. The download, presentation and data processing were done by developed C++ software that runs in a Windows environment. Strong compression and impact forces were recorded, suggesting a need for changes in the mechanical and manual selection, packing and transportation of fruits. Four different prototypes were developed, two corded and two wireless versions. The devices developed were proven to be useful, worked as expected and their modular design permit future developments. The results allowed for different research concerning the damages suffered by the fruits, during the post harvest process.

Este trabalho apresentada um estudo experimental do fenômeno de biestabilidade que ocorre na geometria simplificada de dois tubos dispostos lado a lado submetidos a um escoamento cruzado turbulento. Na análise consideram-se a condição de tubos fixos e com um grau de liberdade (rotacional), submetidos a diferentes números de Reynolds. A técnica experimental consiste na medição de flutuações de velocidade do escoamento através da anemometria de fio quente em canal aerodinâmico, na avaliação dos esforços do escoamento sobre os tubos com o uso de uma célula de carga e na visualização dos efeitos do fenômeno biestável sobre os tubos livres para rotacionar. Os dados obtidos da medição no canal são tratados com o uso de ferramentas estatísticas, espectrais e de ondaletas. Os resultados das visualizações do escoamento são apresentados através de imagens obtidas das filmagens realizadas com uma câmera digital. A investigação experimental consiste de ensaios de cilindros rígidos elasticamente montados e pivotados na base e posteriormente liberados para oscilar e/ou rotacionar em um eixo central aos dois tubos, submetidos ao escoamento perpendicular permanente de ar no canal Nos resultados experimentais observam-se a presença da biestabilidade e nota-se o comportamento não simultâneo deste fenômeno ao longo dos cilindros. A formação assimétrica das esteiras também é estudada e atribuída à interação entre os vórtices das esteiras, já que, inicialmente, o desprendimento dos vórtices atrás dos cilindros é simétrico. Na avaliação dos esforços por extensiometria, as etapas de condicionamento e aquisição do sinal foram elaboradas e os resultados de deformação mecânica apresentaram similaridade com o fenômeno observado na anemometria experimental. Para um número de Reynolds de 27635 encontrou-se uma força de 26,1 mN com um torque desenvolvido na célula de carga de 84,95Nmm. A técnica de visualização do fenômeno empregada corrobora a interpretação dos resultados obtidos através da técnica de anemometria de fio quente e extensiometria em canal aerodinâmico. / This paper presents an experimental study of the bistability phenomenon that occurs in the simplified geometry of two tubes arranged side by side submitted to a turbulent cross flow. In the analysis we consider the condition of fixed tubes and with a degree of freedom (rotational), submitted to different Reynolds numbers. The experimental technique consists in the measurement of velocity fluctuations through the aerodynamic channel with the hot wire anemometry technique, the evaluation of the stresses of the flow on the tubes with the use of a load cell and the visualization of the effects of the bistable phenomenon on the tubes free to rotate. The data obtained from the measurement in the channel are treated with the use of statistical, spectral and wavelet tools. The results of the flow visualizations are presented through images obtained with a high speed digital camera. The experimental investigation consists of tests of rigid cylinders mounted elastically and pivoted at the base and later released to oscillate and / or to rotate in a central axis to the two tubes, submitted to the flow of air in the channel In the experimental results we observe the presence of bistability and note the non-simultaneous behavior of the phenomenon along the cylinders. The asymmetric formation of the wakes is also studied and attributed to the interaction between the vortices from wakes behind the cylinders, since, initially, the wake detachments is symmetrical. In the evaluation of the forces by means of the extensiometry technique, the steps of conditioning and acquisition of the signal were elaborated and the results of mechanical deformation presented similarity with the phenomenon observed in the experimental anemometry. For a Reynolds number of 27635 a force of 26.1 mN was found with a torque developed in the load cell of 84.95 Nmm. The technique used for the visualization of the phenomenon corroborates the interpretation of the results obtained through hot wire anemometry and extensiometry in aerodynamic channel.

Neste trabalho foram desenvolvidos sistemas de aquisição portáteis de formato esférico, capazes de sensoriar forças de compressão e impacto ao longo dos três eixos cartesianos. Os instrumentos desenvolvidos foram utilizados em diferentes experimentos feitos em estabelecimentos de beneficiamento de frutas (packinghouses) durante o processo de pós-colheita a fim de verificar os danos mecânicos sofridos pelas mesmas. Os instrumentos são sistemas microcontrolados compostos por quarto sensores (acelerômetros, célula de carga, temperatura e umidade), memória Flash para o armazenamento dos dados, transceptor de rádio freqüência e uma porta de comunicações serial universal (USB). A coleta, apresentação e processamentos dos dados obtidos foram feitos por um software desenvolvido em ambiente C++ para o sistema operacional Windows. Fortes forças de compressão e impacto foram registradas, sugerindo a necessidade de mudanças no processo de seleção (mecânica e manual), empacotamento e transporte de frutas. Quatro protótipos diferentes foram desenvolvidos, dois com cabos e dois sem. Os dispositivos provaram ser úteis, funcionando como esperado e o seu projeto modular permite o desenvolvimento de diferentes instrumentos. Os resultados obtidos propiciaram pesquisas relativas aos danos sofridos por frutas durante o processo de pós-colheita. / In this work, spherical shape portable data acquisition systems that are capable of sensing compression and impact forces along the three Cartesian axes were developed. The developed instruments were utilized in several different experiments done in fruit packinghouses during the post harvest process in order to check the mechanical damages they suffer. They are microcontrolled systems composed by four sensors (accelerometers, load cell, temperature and humidity), Flash memory for data storage, radio frequency transceiver and a universal serial bus (USB) communication port. The download, presentation and data processing were done by developed C++ software that runs in a Windows environment. Strong compression and impact forces were recorded, suggesting a need for changes in the mechanical and manual selection, packing and transportation of fruits. Four different prototypes were developed, two corded and two wireless versions. The devices developed were proven to be useful, worked as expected and their modular design permit future developments. The results allowed for different research concerning the damages suffered by the fruits, during the post harvest process.

Este trabalho apresentada um estudo experimental do fenômeno de biestabilidade que ocorre na geometria simplificada de dois tubos dispostos lado a lado submetidos a um escoamento cruzado turbulento. Na análise consideram-se a condição de tubos fixos e com um grau de liberdade (rotacional), submetidos a diferentes números de Reynolds. A técnica experimental consiste na medição de flutuações de velocidade do escoamento através da anemometria de fio quente em canal aerodinâmico, na avaliação dos esforços do escoamento sobre os tubos com o uso de uma célula de carga e na visualização dos efeitos do fenômeno biestável sobre os tubos livres para rotacionar. Os dados obtidos da medição no canal são tratados com o uso de ferramentas estatísticas, espectrais e de ondaletas. Os resultados das visualizações do escoamento são apresentados através de imagens obtidas das filmagens realizadas com uma câmera digital. A investigação experimental consiste de ensaios de cilindros rígidos elasticamente montados e pivotados na base e posteriormente liberados para oscilar e/ou rotacionar em um eixo central aos dois tubos, submetidos ao escoamento perpendicular permanente de ar no canal Nos resultados experimentais observam-se a presença da biestabilidade e nota-se o comportamento não simultâneo deste fenômeno ao longo dos cilindros. A formação assimétrica das esteiras também é estudada e atribuída à interação entre os vórtices das esteiras, já que, inicialmente, o desprendimento dos vórtices atrás dos cilindros é simétrico. Na avaliação dos esforços por extensiometria, as etapas de condicionamento e aquisição do sinal foram elaboradas e os resultados de deformação mecânica apresentaram similaridade com o fenômeno observado na anemometria experimental. Para um número de Reynolds de 27635 encontrou-se uma força de 26,1 mN com um torque desenvolvido na célula de carga de 84,95Nmm. A técnica de visualização do fenômeno empregada corrobora a interpretação dos resultados obtidos através da técnica de anemometria de fio quente e extensiometria em canal aerodinâmico. / This paper presents an experimental study of the bistability phenomenon that occurs in the simplified geometry of two tubes arranged side by side submitted to a turbulent cross flow. In the analysis we consider the condition of fixed tubes and with a degree of freedom (rotational), submitted to different Reynolds numbers. The experimental technique consists in the measurement of velocity fluctuations through the aerodynamic channel with the hot wire anemometry technique, the evaluation of the stresses of the flow on the tubes with the use of a load cell and the visualization of the effects of the bistable phenomenon on the tubes free to rotate. The data obtained from the measurement in the channel are treated with the use of statistical, spectral and wavelet tools. The results of the flow visualizations are presented through images obtained with a high speed digital camera. The experimental investigation consists of tests of rigid cylinders mounted elastically and pivoted at the base and later released to oscillate and / or to rotate in a central axis to the two tubes, submitted to the flow of air in the channel In the experimental results we observe the presence of bistability and note the non-simultaneous behavior of the phenomenon along the cylinders. The asymmetric formation of the wakes is also studied and attributed to the interaction between the vortices from wakes behind the cylinders, since, initially, the wake detachments is symmetrical. In the evaluation of the forces by means of the extensiometry technique, the steps of conditioning and acquisition of the signal were elaborated and the results of mechanical deformation presented similarity with the phenomenon observed in the experimental anemometry. For a Reynolds number of 27635 a force of 26.1 mN was found with a torque developed in the load cell of 84.95 Nmm. The technique used for the visualization of the phenomenon corroborates the interpretation of the results obtained through hot wire anemometry and extensiometry in aerodynamic channel.

Neste trabalho foram desenvolvidos sistemas de aquisição portáteis de formato esférico, capazes de sensoriar forças de compressão e impacto ao longo dos três eixos cartesianos. Os instrumentos desenvolvidos foram utilizados em diferentes experimentos feitos em estabelecimentos de beneficiamento de frutas (packinghouses) durante o processo de pós-colheita a fim de verificar os danos mecânicos sofridos pelas mesmas. Os instrumentos são sistemas microcontrolados compostos por quarto sensores (acelerômetros, célula de carga, temperatura e umidade), memória Flash para o armazenamento dos dados, transceptor de rádio freqüência e uma porta de comunicações serial universal (USB). A coleta, apresentação e processamentos dos dados obtidos foram feitos por um software desenvolvido em ambiente C++ para o sistema operacional Windows. Fortes forças de compressão e impacto foram registradas, sugerindo a necessidade de mudanças no processo de seleção (mecânica e manual), empacotamento e transporte de frutas. Quatro protótipos diferentes foram desenvolvidos, dois com cabos e dois sem. Os dispositivos provaram ser úteis, funcionando como esperado e o seu projeto modular permite o desenvolvimento de diferentes instrumentos. Os resultados obtidos propiciaram pesquisas relativas aos danos sofridos por frutas durante o processo de pós-colheita. / In this work, spherical shape portable data acquisition systems that are capable of sensing compression and impact forces along the three Cartesian axes were developed. The developed instruments were utilized in several different experiments done in fruit packinghouses during the post harvest process in order to check the mechanical damages they suffer. They are microcontrolled systems composed by four sensors (accelerometers, load cell, temperature and humidity), Flash memory for data storage, radio frequency transceiver and a universal serial bus (USB) communication port. The download, presentation and data processing were done by developed C++ software that runs in a Windows environment. Strong compression and impact forces were recorded, suggesting a need for changes in the mechanical and manual selection, packing and transportation of fruits. Four different prototypes were developed, two corded and two wireless versions. The devices developed were proven to be useful, worked as expected and their modular design permit future developments. The results allowed for different research concerning the damages suffered by the fruits, during the post harvest process.

The purpose of this bachelor’s thesis is to investigate and construct a computerized electric control handle for a lifting system. The goal is to construct a prototype that can enable lifts with a weightless feeling. Initially, a literature study was conducted to investigate different possible solutions. Three different sensors were evaluated in the literature study. A load cell proved to be best suited for this project. Furthermore, a prototype was constructed where a signal from a load cell could regulate the speed and direction of an electric DC motor with a worm gear. After the prototype was constructed, it was assessed by 17 people. Overall, they all agreed that the lifting experience was good or decent. Finally, it was found that it is possible to create an electric lifting system that enables lifting with a feeling of weightlessness with the help of a load cell and an electric DC motor with a worm gear. There are also opportunities for further development such as better regulation with control engineering theories. Since this project had both a strict schedule and a tight budget to relate to, it has been difficult to develop the concept to its full potential. / Syftet med denna kandidatuppsats är att undersöka och konstruera ett datoriserat elektriskt manöverhandtag för ett lyftsystem. Målet är att konstruera en prototyp som kan möjliggöra lyft med en viktlös känsla. Inledningsvis gjordes en litteraturstudie för att undersöka olika möjliga lösningar. Tre olika sensorer utvärderades i litteraturstudien. En lastcell visade sig vara bäst lämpad för detta projekt. Vidare konstruerades en prototyp där en signal från en lastcell kunde reglera hastighet och riktning på en elektrisklik strömsmotor med snäckväxel. Efter att prototypen konstruerats bedömdes den av 17 personer. Sammantaget var de alla överens om att lyftupplevelsen var bra eller okej. Slutligen fann man att det går att skapa ett elektriskt lyftsystem som möjliggör lyft med en känsla av viktlöshet med hjälp av en lastcell och en elektrisk likströmsmotor med snäckväxel. Det finns också möjligheter till vidareutveckling såsom bättre reglering med reglertekniska teorier. Eftersom detta projekt haft både ett strikt schema och en stram budget att förhålla sig till har det varit svårt att utveckla konceptet till sin fulla potential.

The aim of this thesis is to investigate the potential of replacing the material 1.4418 (R87), currently used in ABB's PFCL201 load cells, with the material 1.402 (R03). Both materials possess desirable properties, including high strength, toughness and magnetoelastic characteristics, making them suitable for force transducer applications in strip tension systems. However, the scarcity and high cost of R87 necessitate exploring the feasibility of utilizing the more affordable and easily obtainable R03. The research methodology involved a combination of mechanical and thermal simulations, as well as the evaluation of prototype measurements made from R03. Mechanical simulations were conducted to identify a new load cell geometry that would facilitate the use of R03, while thermal simulations focused on comparing the thermal properties of R03 with real-life measurements. Furthermore, prototypes made from R03 were tested to investigate the transducer characteristics of the material. Lastly, a cost analysis was performed, comparing the manufacturing costs associated with R87 and R03. The study yielded promising results. R03 improves the manufacturing process and significantly reduces the costs related to it. A new load cell geometry was identified, which could be manufactured using existing resources at the factory. Thermal simulations demonstrated improvements in the thermal properties when employing R03. However, measurements of the PFCL201-20 kN load cell made from R03, indicated that to maintain the same accuracy class and commutation angle as the current R87 load cells, the nominal load would need to be adjusted to 12 kN instead of 20 kN. Nonetheless, with the identified geometric modifications, R03 load cells could still be utilized as 20 kN load cells. Alternatively, by changing either the accuracy class or commutation angle. This research provides valuable insights into the possibility of replacing the expensive and scarce R87 material with the more cost-effective and readily available R03 in ABB's PFCL201 load cells. The findings offer a foundation for future studies and potential business decisions regarding material selection and load cell design optimization.

Snabbmatsrestauranger har svårt att hålla en bra lagerstyrning på grund av föråldrade inventeringsmetoder. Där manuell inventering sker varje dag för att kontrollera vad som finns i lager. Detta är en tidskrävande process som kräver arbetskraft att utföra. Det uppstår ofta fel i lagersaldo på grund av manuell kontroll, då det handlar om många varor på en liten yta och med en hög lageromsättningshastighet. I andra lagermiljöer används vägning som inventeringsmetod för att underlätta lagerstyrningen. Syftet med denna studie är att undersöka om vägningen är en lämplig metod för att kontrollera lagersaldo i små manuella lager med hög omsättningshastighet hos snabbmatsrestauranger. En empirisk studie genomfördes i form av semistrukturerade intervjuer. Två snabbmatsrestauranger var inblandade, där fyra personer intervjuades, alla respondenterna jobbade inom forskningsområdets specifika lagermiljö och har hand om lagerstyrningen för dessa lager. Två forskningsfrågor besvarades utifrån intervjuerna, vilket bidrog till att uppfylla syftet med studien. En innehållsanalys utfördes på den empiriska datan som samlades in från intervjuerna, för att underlätta bearbetningen av datan och få ut information som kan besvara forskningsfrågorna och syftet med studien. Tidigare forskning visar att vägning är en användbar metod för att kontrollera lagersaldo. Den empiriska studien gav en bättre uppfattning om tekniken skulle kunna användas i små manuella lager med hög omsättningshastighet hos snabbmatsrestauranger. Där svarade respondenterna att denna lagermiljö inte är anpassad för att kunna införa ett fungerande vägningssystem som kan ge ett korrekt lagersaldo. Då det finns många hinder som kan uppstå med att implementera ett fungerande vägningssystem. Ett hinder är att det förvaras många olika artiklar i lagret på en liten yta, vilket leder till problem vid vägningen av varorna. Att det skulle vara svårt att kunna urskilja alla olika artiklar och få ett korrekt vägningsresultat. Ur intervjuerna kom det även fram att förvaring av artiklarna i lagren inte förvaras likadant, vissa produkter staplas på backvagnar, en del förvaras på hyllor medan vissa artiklar är staplade på varandra från marknivå. Vilket försvårar användningen av ett vägningssystem. Under höga försäljningsperioder kan det bli problematiskt med ett vägningssystem, då det kan krävas att artiklar lagras i andra utrymmen än i lagren. Vilket gör ett sådant system irrelevant om den inte kan väga alla artiklar och ge ett korrekt lagersaldo. / Today, fast food restaurants find it difficult to maintain good inventory management due to outdated inventory methods. Where manual inventory takes place every day to check what is in stock. This is a time-consuming process that requires manpower to perform. There are often errors in the stock balance due to manual control, as it involves many goods in a small area and with a high stock turnover rate. In other warehouse environments, weighing is used as an inventory method to facilitate inventory control. The purpose of this study is to investigate whether weighing is a suitable method for controlling inventory balance in small manual warehouses with high turnover rates in the fast foodindustry. An empirical study was conducted in the form of semi-structured interviews. Two fast food restaurants were involved, where four people were interviewed and all the respondents worked within the specific warehouse environment of the research area and are in charge of inventory control for these warehouses. Two research questions were answered based on the interviews, which contributed to fulfilling the purpose of the study. A content analysis was performed on the empirical data collected from the interviews. To facilitate the processing of the data and obtain information that can answer the research questions and the purpose of the study. Previous research shows that weighing is a useful method of controlling inventory balance. The empirical study gave a better idea of whether the technology could be used in small manual warehouses with a high turnover rate. There, the respondents answered that this warehouse environment is not necessarily adapted to be able to introduce a functioning weighing system that can provide an accurate inventory balance. As there are many obstacles that can arise in implementing a functioning weighing system. An obstacle is that many different articles are stored in the warehouse on a small surface, which leads to problems when weighing the goods. That it would be difficult to distinguish all the different articles and get a correct weighing result. The interviews also revealed that the storage of the articles in the warehouses is not the same, some products are stacked on back carts, some are stored on shelves while some articles are stacked on top of each other from ground level. Which complicates the use of a weighing system. During high sales periods, it can become problematic with a weighing system in the warehouse as it may sometimes be required that items be stored in areas other than the warehouses. Which makes such a system irrelevant if it cannot weigh all items and provide an accurate inventory balance.