Academic literature on the topic 'Low-cost testbed'
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Journal articles on the topic "Low-cost testbed"
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Rainer, Benjamin, Daniel Posch, Andreas Leibetseder, Sebastian Theuermann, and Hermann Hellwagner. "A low-cost NDN testbed on banana pi routers." IEEE Communications Magazine 54, no. 9 (September 2016): 105–11. http://dx.doi.org/10.1109/mcom.2016.7565256.
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Murillo, Yuri, Brecht Reynders, Alessandro Chiumento, and Sofie Pollin. "A Multiprotocol Low-Cost Automated Testbed for BLE Mesh." IEEE Communications Magazine 57, no. 3 (March 2019): 76–83. http://dx.doi.org/10.1109/mcom.2019.1800122.
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Shang, Gui-yang, Zheng-ping Feng, and Lian Lian. "A low-cost testbed of underwater mobile sensing network." Journal of Shanghai Jiaotong University (Science) 16, no. 4 (January 7, 2011): 502–7. http://dx.doi.org/10.1007/s12204-010-1084-1.
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Attaby, Abdelhamid, Nada Osman, Mustafa Elnainay, and Moustafa Youssef. "Wipi: A Low-Cost Large-Scale Remotely-Accessible Network Testbed." IEEE Access 7 (2019): 167795–814. http://dx.doi.org/10.1109/access.2019.2953356.
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Vedder, Benjamin, Jonny Vinter, and Magnus Jonsson. "A Low-Cost Model Vehicle Testbed with Accurate Positioning for Autonomous Driving." Journal of Robotics 2018 (November 18, 2018): 1–10. http://dx.doi.org/10.1155/2018/4907536.
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Accurate positioning is a requirement for many applications, including safety-critical autonomous vehicles. To reduce cost and at the same time improving accuracy for positioning of autonomous vehicles, new methods, tools, and research platforms are needed. We have created a low-cost testbed consisting of electronics and software that can be fitted on model vehicles allowing them to follow trajectories autonomously with a position accuracy of around 3 cm outdoors. The position of the vehicles is derived from sensor fusion between Real-Time Kinematic Satellite Navigation (RTK-SN), odometry, and inertial measurement and performs well within a 10 km radius from a base station. Trajectories to be followed can be edited with a custom GUI, where also several model vehicles can be controlled and visualized in real time. All software and Printed Circuit Boards (PCBs) for our testbed are available as open source to make customization and development possible. Our testbed can be used for research within autonomous driving, for carrying test equipment, and other applications where low cost and accurate positioning and navigation are required.
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Guo, Cheng, R. Venkatesha Prasad, Jiang Jie He, Martin Jacobsson, and Ignas G. M. M. Niemegeers. "Designing a flexible and low-cost testbed for Wireless Sensor Networks." International Journal of Ad Hoc and Ubiquitous Computing 9, no. 2 (2012): 111. http://dx.doi.org/10.1504/ijahuc.2012.045554.
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Papakonstantinou, Charalampos, Georgios Moraitis, Vaios Lappas, and Vassilis Kostopoulos. "Design of a Low-Cost Air Bearing Testbed for Nano CMG Maneuvers." Aerospace 9, no. 2 (February 12, 2022): 95. http://dx.doi.org/10.3390/aerospace9020095.
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In this paper, a low-cost, miniature spacecraft attitude control simulator is presented for testing miniature actuators such as Nano Control Moment Gyroscopes (CMGs) for simple maneuvers. The experimental setup is composed by an attitude control system (ACS) that mainly consists of a four-CMG cluster in a pyramid configuration and a custom-made air bearing. The one-degree-of-freedom (DoF) air bearing is fabricated to reproduce the frictionless conditions of a nano-satellite in orbit. The ACS is made exclusively using low-cost commercial-off-the-shelf (COTS) components, whilst the air bearing is made using 3D-printed parts. Both hardware and software implementations are described in detail and the performance of the developed simulator is evaluated by two maneuver experiments. Despite the manufacturing imperfections, the ACS is capable of providing higher angular velocities than previously presented in the literature while following the theoretical or simulation data. The results indicate that it is possible to manufacture a low-cost, miniature actuator such as a CMG, using COTS components to demonstrate the operation of an agile nano-satellite. Any deviations from the theoretical values are addressed and several improvements are discussed to further enhance the performance of the air bearing testing platform.
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Said, Ibrahim A., Naomi Fuentes, Ze He, Ruikun Xin, Kuichang Zuo, and Qilin Li. "Low-cost desalination of seawater and hypersaline brine using nanophotonics enhanced solar energy membrane distillation." Environmental Science: Water Research & Technology 6, no. 8 (2020): 2180–96. http://dx.doi.org/10.1039/d0ew00254b.
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Calero, D., E. Fernandez, and M. E. Parés. "AUTONOMOUS WHEELED ROBOT PLATFORM TESTBED FOR NAVIGATION AND MAPPING USING LOW-COST SENSORS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W8 (November 13, 2017): 67–74. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w8-67-2017.
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This paper presents the concept of an architecture for a wheeled robot system that helps researchers in the field of geomatics to speed up their daily research on kinematic geodesy, indoor navigation and indoor positioning fields. The presented ideas corresponds to an extensible and modular hardware and software system aimed at the development of new low-cost mapping algorithms as well as at the evaluation of the performance of sensors. The concept, already implemented in the CTTC's system ARAS (Autonomous Rover for Automatic Surveying) is generic and extensible. This means that it is possible to incorporate new navigation algorithms or sensors at no maintenance cost. Only the effort related to the development tasks required to either create such algorithms needs to be taken into account. As a consequence, change poses a much small problem for research activities in this specific area. This system includes several standalone sensors that may be combined in different ways to accomplish several goals; that is, this system may be used to perform a variety of tasks, as, for instance evaluates positioning algorithms performance or mapping algorithms performance.
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Adetona, S., L. Ahemba, and A. L. Imoize. "Design and implementation of a low cost experimental testbed for wireless sensor networks." Nigerian Journal of Technology 37, no. 1 (January 17, 2018): 226. http://dx.doi.org/10.4314/njt.v37i1.30.
Full textDissertations / Theses on the topic "Low-cost testbed"
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Ng, Jennifer. "Investigation of a low-cost coaxial helicopter testbed for planetary remote sensing." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/228525/1/Jennifer_Ng_Thesis.pdf.
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This project was a step forward in designing and testing a low-cost coaxial UAV with an optical flow sensor. The research is based on the Mars Helicopter Ingenuity used in planetary remote sensing. The thesis investigated how accurately the UAV can maintain altitude using VICON, LIDAR, and the optical flow sensor.
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Negreiros, Marcelo. "Low cost BIST techniques for linear and non-linear analog circuits." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/6225.
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Com a crescente demanda por produtos eletrônicos de consumo de alta complexidade, o mercado necessita de um rápido ciclo de desenvolvimento de produto com baixo custo. O projeto de equipamentos eletrônicos baseado no uso de núcleos de propriedade intelectual ("IP cores") proporciona flexibilidade e velocidade de desenvolvimento dos chamados "sistemas num chip". Entretanto, os custos do teste destes sistemas podem alcançar um percentual significativo do valor total de produção, principalmente no caso de sistemas contendo "IP cores" analógicos ou "mixed-signal". Técnicas de teste embarcado (BIST e DFT) para circuitos analógicos, embora potencialmente capazes de minimizar o problema, apresentam limitações que restringem seu emprego a casos específicos. Algumas técnicas são dependentes do circuito, necessitando reconfiguração do circuito sob teste, e não são, em geral, utilizáveis em RF. No ambiente de "sistemas num chip", como recursos de processamento e memória estão disponíveis, eles poderiam ser utilizados durante o teste. No entanto, a sobrecarga de adicionar conversores AD e DA pode ser muito onerosa para a maior parte dos sistemas, e o roteamento analógico dos sinais pode não ser possível, além de poder introduzir distorção do sinal. Neste trabalho um digitalizador simples e de baixo custo é usado ao invés de um conversor AD para possibilitar a implementação de estratégias de teste no ambiente de "sistemas num chip". Graças ao baixo acréscimo de área analógica do conversor, múltiplos pontos de teste podem ser usados. Graças ao desempenho do conversor, é possível observar características dos sinais analógicos presentes nos "IP cores", incluindo a faixa de freqüências de RF usada em transceptores para comunicações sem fio. O digitalizador foi utilizado com sucesso no teste de circuitos analógicos de baixa freqüência e de RF. Como o teste é baseado no domínio freqüência, características nãolineares como produtos de intermodulação podem também ser avaliadas. Especificamente, resultados práticos com protótipos foram obtidos para filtros de banda base e para um mixer a 100MHz. A aplicação do conversor para avaliação da figura de ruído também foi abordada, e resultados experimentais utilizando amplificadores operacionais convencionais foram obtidos para freqüências na faixa de áudio. O método proposto é capaz de melhorar a testabilidade de projetos que utilizam circuitos de sinais mistos, sendo adequado ao uso no ambiente de "sistemas num chip" usado em muitos produtos atualmente.With the ever increasing demands for high complexity consumer electronic products, market pressures demand faster product development and lower cost. SoCbased design can provide the required design flexibility and speed by allowing the use of IP cores. However, testing costs in the SoC environment can reach a substantial percent of the total production cost. Analog testing costs may dominate the total test cost, as testing of analog circuits usually require functional verification of the circuit and special testing procedures. For RF analog circuits commonly used in wireless applications, testing is further complicated because of the high frequencies involved. In summary, reducing analog test cost is of major importance in the electronic industry today. BIST techniques for analog circuits, though potentially able to solve the analog test cost problem, have some limitations. Some techniques are circuit dependent, requiring reconfiguration of the circuit being tested, and are generally not usable in RF circuits. In the SoC environment, as processing and memory resources are available, they could be used in the test. However, the overhead for adding additional AD and DA converters may be too costly for most systems, and analog routing of signals may not be feasible and may introduce signal distortion. In this work a simple and low cost digitizer is used instead of an ADC in order to enable analog testing strategies to be implemented in a SoC environment. Thanks to the low analog area overhead of the converter, multiple analog test points can be observed and specific analog test strategies can be enabled. As the digitizer is always connected to the analog test point, it is not necessary to include muxes and switches that would degrade the signal path. For RF analog circuits, this is specially useful, as the circuit impedance is fixed and the influence of the digitizer can be accounted for in the design phase. Thanks to the simplicity of the converter, it is able to reach higher frequencies, and enables the implementation of low cost RF test strategies. The digitizer has been applied successfully in the testing of both low frequency and RF analog circuits. Also, as testing is based on frequency-domain characteristics, nonlinear characteristics like intermodulation products can also be evaluated. Specifically, practical results were obtained for prototyped base band filters and a 100MHz mixer. The application of the converter for noise figure evaluation was also addressed, and experimental results for low frequency amplifiers using conventional opamps were obtained. The proposed method is able to enhance the testability of current mixed-signal designs, being suitable for the SoC environment used in many industrial products nowadays.
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Al, Daher Nour El Huda. "Performance analysis and market evaluation of a low cost spectrum analyzer for IOT testing platform." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22580/.
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This project is about designing, developing and controlling an electromechanical test bench which will be used for parallel radio spectrum measurements of company produced devices. In general the aim is to utilize all the available tools to decrease the time of testing and optimize it.
The created application was developed in python language over Linux, and has the role to check, process, and send information feedback for instance power and frequency for LoRa Devices using spectrum analyzer “LTDZ”.
In order to read the signal we needed to setup the right parameters that match the SA, and define in my software the samples number, step size, frequency range and others. In addition in the way how to translate the data received in a readable values.
If the signal as expected we continue the process to assign specification for the device, and print them to be delivered to users with each LoRa device. Otherwise a warning led is turning under the desire device using the GPIO in the BeagleBone Black.
This single process must be integrated to test an array of LoRa devices using multiple LTDZ spectrum analyzers in order to check the signals in parallel and simultaneously.
The achieved goal after testing was positive, even though the spectrum analyzer had some limitations needed to be solved. In conclusion we are able to get the desired power in the specified frequency.
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Nascimento, Thiago Mazzú do. "Plataformas de baixo custo à base de papel para testes imunodiagnósticos e enzimáticos." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-13032017-090102/.
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Os imunoensaios e os ensaios bioquímicos são amplamente utilizados em clinica médica. Os dispositivos fabricados em papel devido ao seu baixo custo, portabilidade, todas as etapas serem realizadas em temperatura ambiente, e possibilidade da produção local dos dispositivos, tornam-se ideais para serem aplicados em regiões carentes. Assim, desenvolvemos um ensaio imunocromatográfico que permitiu a detecção de IgG de coelho em um dispositivo com uma única camada de papel impressa por cera, mostrando que esse protótipo tem potencial de ser aplicado em diferentes ensaios imunológicos. Pela primeira vez foi utilizado um teste enzimático colorimétrico (sarcosina oxidase, peroxidase e o indicador redox (ABTS) em plataforma de papel, impressa por cera, para detecção de sarcosina, o qual detectou um potencial marcador de tumor de câncer de próstata, a sarcosina, com limite de detecção (LD) = 0,21 mmol L-1 e limite de quantificação (LQ) = 0,61 mmol L-1, constatando que a intensidade da cor formada foi proporcional a concentração de sarcosina presente na amostra. Os imunoensaios em papel se mostraram extremamente versáteis, capazes de detectar diferentes analitos. O primeiro dispositivo foi capaz de detectar toxoplasmose (IgG contra T. gondii presente nas amostras). A avaliação da performance do teste nos forneceu um cut-off =21,73 U.A, sensibilidade = 0,96, especificidade = 0,87, AUC = 0,97, além de uma criação de uma zona cinza utilizando uma tolerância em porcentagem sobre a o cut-off de 15%. Desenvolvemos também uma macro no excel qye calcula a acurácia, m-Acuraccy, a qual nos forneceu um valor de 0,88 U.A. O segundo dispositivo permitiu a detecção do marcador tumoral CEA, através de um ensaio do tipo sanduíche, com um cut-off =68,28 U.A, sensibilidade = 0,86, especificidade = 1, AUC = 0,97. A tolerância em porcentagem sobre a o cut-off para a criação da zona cinza foi de 12%, e a m-Acuraccy calculou uma acurácia de 0,90 U.A. Pela primeira vez, foi aplicada essa completa avaliação estatística em testes em papel. Mais do que isso, trazemos com a m-Acuraccy uma nova forma de calcular a acurácia, com grande inovação na clínica médica. Portanto, torna-se evidente o grande potencial que os dispositivos fabricados em papel possuem para ser aplicados como ferramentas diagnósticas.Immunoassays and bioassays are broadly used in clinical medicine. Paper-based devices are ideal to be used in remote regions due to their low-cost, portability and the possibility of in loco manufacture. Paper-based immunoassays are extremely versatile, capable of detecting distinct analytes: initially we have developed an immunochromatographic assay to detect rabbit IgG in a paper-based device fabricated using wax printing technology, and we have shown that this prototype has potential to be applied in distinct immunoassays. The second developed paper-based device was an enzymatic colorimetric assay for the detection of a potential prostate cancer biomarker - sarcosine (sarcosine oxidase, peroxidase and redox indicator (ABTS)), obtaining good figures or merit (LOD = 0.21 mmol L-1; LOQ = 0.61 mmol L-1, r² = 0.890). The third developed paper-based device was capable of detecting toxoplasmosis (IgG against Toxoplasma gondii in human serum samples). The performance evaluation showed a cut-off = 21.73 A.U., sensitivity = 0.96, specificity = 0.87, AUC = 0.97, besides defining the gray zone as the zone comprehended in-between 15% over the cut-off value. We also have developed a Microsoft Excel® macro to calculate diagnostic test\'s accuracy - m-Accuracy - that is a new way to calculate accuracy with great innovation for clinical medicine, which resulted in an accuracy of 0.88. for toxoplasmosis assay. The fourth developed paper-based device was used to detect CEA tumor biomarker using a sandwich ELISA assay, with a cut-off = 68.28 A.U., sensitivity = 0.86, specificity = 1.0, AUC = 0.97. The defined gray zone to this test was the zone comprehended in-between 12% over the cut-off value, with an accuracy of 0.90. To the best of our knowledge, this is the first complete statistical evaluation of paper-based diagnostic devices, which showed the great potential of this technology to be used as a new point-of care diagnostic tool.
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Silva, Nathalia Priscila Oliveira. "Validade e reprodutibilidade do Wii Balance Board para avalia??o do equil?brio vertical est?tico: um novo m?todo de avalia??o." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16750.
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The Wii Balance Board (WBB) began to be investigated as a low-cost alternative for assessing static balance in vertical posture. However, studies employed methodological procedures that did not eliminate result variability between the tests and equipment used. Objective: Determine the validity and reproducibility of the WBB as an instrument for assessing static balance in the vertical position, using simultaneous data analysis and superimposed equipment. Methods: This is an accuracy study of 29 healthy young individuals of both sexes aged 18 to 30 years. Subjects were assessed 24h apart (test-retest), using unipodal and bipodal support tests, with eyes closed and open. To that end the WBB was placed on top of a force platform (FP) and data (postural sway) were collected simultaneously on both devices. Validity and reproducibility were analyzed using the interclass correlation coefficient (ICC). Finally, Bland-Altman analysis was applied to assess agreement. Results: The sample was composed of 23 women and 6 men, with mean age of 24.2?6.3 years, 60.7?6.3 kg and 1.64?4.2 m. The validity of the WBB compared to the FP was excellent for all 4 tasks proposed (ICC = 0.93 0.98). The reproducibility analyzed by test-retest was excellent for the bipodal support tasks (ICC = 0.93-0.98) and only moderate for the unipodal support tests (ICC = 0.46 0.70). Graphic analysis exhibited good agreement between the devices, since most of the measures were within the limits of agreement. Conclusion: this study proved the validity and reproducibility of the Wii Balance Board as an instrument for assessing static balance in vertical posture, using simultaneous analysis with superimposed equipment. Thus, the WBB has been increasingly used by physical therapists and other health professionals in their clinical practice, as both a rehabilitation and assessment tool
O Wii Balance Board (WBB) passou a ser investigado como uma alternativa de baixo custo para avalia??o do equil?brio est?tico na postura vertical. No entanto, as pesquisas utilizaram procedimentos metodol?gicos que n?o eliminaram a variabilidade de resultados existente entre os testes e equipamentos utilizados. Objetivo: Averiguar as propriedades de validade e reprodutibilidade do WBB como instrumento para avalia??o do equil?brio est?tico na postura vertical, por meio do m?todo de an?lise simult?nea de dados com a sobreposi??o de equipamentos. M?todos: Trata-se de um de estudo de acur?cia, no qual foram avaliados 29 jovens saud?veis de ambos os sexos de 18-30 anos. Os inviv?duos foram avaliados em 2 momentos distintos com intervalo de 24h (teste-reteste), atrav?s de testes de apoio unipodal e bipodal com olhos fechados e abertos. Para isso o WBB foi colocado sobre a Plataforma de for?a (PF) e a coleta dos dados (deslocamento total do Centro de Press?o) foi feita simultaneamente em ambos equipamentos. A validade e reprodutibilidade foram analisadas atrav?s do coeficiente de correla??o intraclasse (CCI). Por fim, foi feita uma an?lise de concord?ncia por meio do m?todo de Bland-Altman. Resultados: A amostra foi composta por 23 mulheres e 6 homens, com idade m?dia de 24,2?6,3 anos, 60,7?6,3 kg e 1,64?4,2 m. A validade do WBB em compara??o com a PF mostrou-se excelente para todas as 4 tarefas propostas (CCI = 0,93 0,98). A reprodutibilidade analisada atrav?s do teste-reteste mostrouse excelente para as tarefas de apoio bipodal (CCI = 0,93 0,88) e apenas moderada para os testes de apoio unipodal (CCI = 0,46 0,70). Na an?lise gr?fica, viu-se uma boa concord?ncia entre os dispositivos, j? que a maioria das medidas encontra-se dentro dos limites concord?ncia. Conclus?o: esta pesquisa provou a validade e reprodutibilidade do Wii Balance Board como um instrumento para avalia??o do equil?brio est?tico na postura vertical, atrav?s da an?lise simult?nea com sobreposi??o de equipamentos. Tornando o WBB cada vez mais vi?vel para sua utiliza??o na pr?tica cl?nica pelos fisioterapeutas e diversos profissionais de sa?de, n?o apenas como uma ferramenta de reabilita??o mas tamb?m de avalia??o
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Syu, Jia-Hao, and 許家豪. "Implementation of a Low-cost Breath Alcohol Tester." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/w5mg52.
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碩士國立高雄第一科技大學
電子工程研究所
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In this study, a low-cost breath alcohol tester based on gas concentration measurement technology was proposed and a human breathing simulation and correction system was developed. A high-precision police-grade alcohol tester was developed at a low cost by using semiconductor and electrochemical gas sensors, and was compared with a police-grade alcohol content detector and the human breathing simulation and correction system. The test results show that a statistical regression curve is required for the semiconductor sensor to perform data correction in order to achieve high accuracy. On the other hand, the accuracy of the electrochemical sensor depends on the precision of the chemical reactions within the sensor. Therefore, the electrochemical sensor has the advantages of little interference imposed by environmental variables and high precision. However, chemical reactions lead to a decrease in the service life of the sensor; moreover, the sensor needs to be periodically recalibrated. In this study, two types of sensors were used to develop a police-grade alcohol tester system with high precision and stability. Further, the characteristics of the alcohol tester system were analyzed. This study provides the basis for rapid construction of an alcohol tester system at low cost.
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Low, William. "An integrated low-cost functional tester for CMOS logic." Thesis, 1993. http://hdl.handle.net/2429/4946.
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This thesis focuses on improving the quality of tests performed by low-cost testers for Very Large
Scale Integration (VLSI) chips. The testing of timing parameters become increasingly important
with higher performance technology. Circuits that operate correctly at low speeds may fail at higher
speeds because of timing problems. Most low-end test systems lack the performance required to
conduct the timing diagnostics needed to perform more advanced testing of modern VLSI chips.
Areas of improvement in low-cost test systems include increasing vector memory, test speed,
or I/O timing and wave formatting capability. Increasing I/O timing and wave formatting capability
provides a good compromise of improved tester functionality at a reasonable cost. These features
provide considerably more improvements in test quality than simply increasing the raw test speed
(or test pattern rate).
A test strategy was developed that exploits this improved timing and I/O waveform for
matting capability to generate short high-speed clock bursts which can be used to perform testing
at speeds equivalent to a much higher rate than the tester’s pattern rate. This strategy can be
used to test many digital designs. However, using this strategy for “high-speed” testing requires
more effort in test pattern development and more test vectors than an equivalent test performed
on a high-speed tester. This approach can also be used in existing high-end testers that already
have the required timing and waveform formatting capabilities.
A functional tester system for CMOS logic was developed that provides these improved
timing and I/O formatting features. This system integrates most of tester circuits into modular
functional tester chips (FTCs) which are used in parallel to form a tester. Vector encoding combined
with an internal lookup table was used to reduce the memory bandwidth required to support the
increased functionality.
A single-channel FTC was designed and implemented on a 3.8mm x 2.9mm die and requires
only 40-pins which gives considerable allowance for future increases in memory width and channels.
Measurements from earlier prototypes of the FTC waveform formatter give worst case timing
resolutions of 1ns and maximum rise-fall skews of 1.2ns. Worst case skews between devices were on
the order of 1ns. These results are very reasonable considering the relatively conservative standard
cell design using 1.2m CMOS.
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Soares, Angelo Roldão. "Desenvolvimento e teste de um protótipo móvel com sensores low cost." Master's thesis, 2018. http://hdl.handle.net/10451/35294.
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Tese de mestrado integrado em Engenharia da Energia e do Ambiente, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, em 2018Apesar de grande parte da poluição ter lugar no exterior, o ambiente interior não está incólume às movimentações de ar que a trazem para dentro dos edifícios, poluição essa nas grandes cidades com origem nos produtos da combustão ou operações industriais. Casos extremos de poluição são, por exemplo, cidades como Beijing com graves casos de smog nos últimos anos. A juntar à poluição exterior que inevitavelmente contamina os espaços interiores, temos também a própria habitação do edifício que gera a produção de CO2 por parte dos ocupantes, o que também afeta a qualidade do ar. Todos estes fatores levam a uma preocupação acrescida na compreensão e monitorização de determinados gases e os seus impactos na saúde humana. Para se poder afirmar que existem impactos e que existe presença de gases nocivos no ar ambiente, é preciso instrumentação capaz de os detetar. A ideia para esta dissertação surge no contexto da campanha Breathable Cities World Campaign, uma campanha filantrópica que visa contribuir para a melhoria da qualidade de vida do homem em completa harmonia com o ambiente. Com o intuito de quantificar os poluentes, a iniciativa Breathable Cities Campaign utilizou equipamentos extremamente dispendiosos na ordem dos milhares de euros. Esta dissertação procura obter o mesmo tipo de informação quantitativa dos gases, mas através de aparelhos low cost na ordem das dezenas de euros utilizando uma placa Arduíno que faz de interface entre uma cloud network e os sensores DHT11, MQ-131 e MG-811, servindo assim como plataforma de motivação da dissertação, sendo o principal desafio a construção e teste do protótipo. Com esta dissertação disponibilizam-se as ferramentas para qualquer académico recrear esta experiência e criar uma estação de monitorização de gases com um peso financeiro menor, o preço de todos os componentes totalizou 158.3 euros e o protótipo tem um peso de cerca de 442 gramas. O foco na instrumentação foi alvo de grande ponderação, pois é necessário estudar aprofundadamente toda a temática dos sensores e os seus métodos de comunicação, assim como a melhor forma de proceder à construção e teste do aparelho. Para se testar o funcionamento do protótipo foi prudente considerar dois tipos de calibrações possíveis dos sensores de CO2 e O3, porém, o método dos mínimos quadrados revelou-se superior às metodologias de fábrica propostas devido à sua simplicidade. Os dados obtidos foram satisfatórios, no entanto é preciso relembrar que estamos a falar de sensores extremamente low cost e que deverão ser efetuados testes mais extensos em melhores condições de calibração. Foi possível concluir esta dissertação com um protótipo funcional capaz de fazer medições rudimentares e efetuar comunicação por cloud network. É um proof-of-concept com espaço para melhorias como a redução das dimensões e do peso investindo em circuitos integrados ou placas PCB. É possível também testar-se a utilização de sensores mais robustos que podem teoricamente proporcionar melhores resultados de calibração ao depender menos de fatores como a temperatura e a humidade, ou simplesmente assegurar melhores condições de calibração com os sensores que foram testados.
Despite a big portion of pollution being generated outdoors, indoor environment is not unaffected by air mass movements that bring that pollution inside. In big cities pollution has its origins in combustion or industrial operations and can be observed, in extreme, in cities like Beijing, with severe cases of smog in the past years. Besides outdoor pollution that inevitably contaminates indoor environments, we also have the CO2 production associated with the presence of users in indoors spaces, which by itself also affects air quality. All these factors further the necessity of monitoring and comprehending pollutants and their impacts on human health. In order to make affirmations about the impact of air pollutants and measure the presence of such pollutants in ambient air, we need instrumentation that is capable of detecting them. The idea for this dissertation comes about in the context of the Breathable Cities World Campaign, a philanthropic campaign whose objective is to promote a better quality of life for mankind and the balance between man and nature. The Breathable Cities World Campaign, with the purpose of quantifying air pollutants, used extremely expensive equipment with values in the range of thousands of euros. This dissertation procures to obtain the same type of quantifying information, but with low cost devices with a price in the dozens of euros by making use of an Arduino Board, which acts as an interface between a cloud network and a DHT11, MQ-131 and MG-811 sensors. This served as the motivational platform for this dissertation making the construction and testing of a low cost prototype the main focus. This dissertation gives the tools necessary for any academic to recreate the experience and create a cheap air quality monitoring station. The prototype which weighs about 442 grams has amounted to a total expenditure of 158.3 euros. The focus on instrumentation was target of great analysis as it’s necessary to deeply study the whole thematic of sensors and how they operate. It was also important to understand their methods of communication and how we should proceed with the construction and test of the device. A cautious approach was taken with the calibration of the CO2 and O3 sensors taking two different methods into consideration. The minimum squares method revealed itself as the superior approach when compared with factory methodologies, due to its simplicity. The data gathered from the sensors was satisfactory though it should be noted that we’re discussing extremely low cost sensors and we should be careful with taking conclusions without making more extensive tests with better calibration conditions. It was possible to conclude this dissertation with a functional prototype that was capable of making rudimentary measurements and communicate through cloud networking. It’s a proof-of-concept prototype with room for improvement, such as reducing the dimensions and weight by investing in integrated circuits or PCB boards. It’s also possible to theoretically obtain better results in calibration tests by testing more robust sensors that have less dependency of factors such as temperature and humidity, or we could use the same sensors in this dissertation but with better calibration conditions.
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Chen, Yu-Lang, and 陳玉郎. "The Study of PLL and DLL and Its Application to Low Cost Tester." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/22954784925474425620.
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碩士國立交通大學
電資學院學程碩士班
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A timing generator (TG) is the most important part on the tester timing control system. It is the key factor for speeding up tester's cycle rate. Here, This research uses an alternative way to build our tester timing generator. It is different from the traditional methodology, and they used to build timing generator by current steering DAC, capacitor and comparator. In this thesis, it uses a phase locked loop to multiply the input clock rate by 4, and then use a delay locked loop to divide the clock period into 4 equal sections again. The PLL and DLL simulation have been accomplished by using lower level and lower cost technology, TSMC .6U CMOS technology. Its performance could have PLL output 400MHZ clock, and the DLL output minimum stable phase delay reach 0.625ns. 0.625ns is the minimum resolution to a tester's timing generator. We could use this circuit to supply 100MHZ data rate on a tester's TG. This methodology uses extern clock to adjust PLL and DLL output. They both used the feedback loop to control their output. So the immunity to the deviation of power supply and temperature is better than the traditional design. Although its resolution is larger, its' accuracy is still better, typical RMS accuracy < 3ps.
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Lin, Gong-Yi, and 林功藝. "Design and implementation of a PC-based low-cost general-purpose digital IC function tester." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/25503064018600733214.
Full textBooks on the topic "Low-cost testbed"
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Low-cost marketing strategies: Field-tested techniques for tight budgets. New York: Praeger, 1987.
Find full textBook chapters on the topic "Low-cost testbed"
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Doddavenkatappa, Manjunath, Mun Choon Chan, and A. L. Ananda. "Indriya: A Low-Cost, 3D Wireless Sensor Network Testbed." In Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 302–16. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29273-6_23.
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Šolc, Tomaž, Carolina Fortuna, and Mihael Mohorčič. "Low-Cost Testbed Development and Its Applications in Cognitive Radio Prototyping." In Cognitive Radio and Networking for Heterogeneous Wireless Networks, 361–405. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-01718-1_13.
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Sanchez-Lopez, Jose Luis, Changhong Fu, and Pascual Campoy. "FuSeOn: A Low-Cost Portable Multi Sensor Fusion Research Testbed for Robotics." In Advances in Intelligent Systems and Computing, 57–68. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-27146-0_5.
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Guo, Cheng, R. Venkatesha Prasad, JiangJie He, and Martin Jacobsson. "FIST: A Framework for Flexible and Low-Cost Wireless Testbed for Sensor Networks." In Communication and Networking, 216–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-10844-0_27.
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Nsunza, Watipatsa W., Samuel Rutunda, and Xiaojun Hei. "Design and Implementation of a Low-Cost Software Defined Wireless Network Testbed for Smart Home." In Security, Privacy, and Anonymity in Computation, Communication, and Storage, 379–88. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-72395-2_35.
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Le-Viet, Hung, Dang Huynh-Van, and Quan Le-Trung. "UiTiOt-Vlab: A Low Cost Physical IoTs Testbed Based on Over-The-Air Programming Approach." In Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 181–92. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-30149-1_15.
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Bezunartea, Maite, Marie-Paule Uwase, Jacques Tiberghien, Jean-Michel Dricot, and Kris Steenhaut. "Demonstrating the Versatility of a Low Cost Measurement Testbed for Wireless Sensor Networks with a Case Study on Radio Duty Cycling Protocols." In Internet of Things. IoT Infrastructures, 222–30. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-47063-4_20.
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Ariya, George. "Towards a symbiotic wildlife tourism destination attractiveness and sustainability framework for national parks in Kenya." In Managing visitor experiences in nature-based tourism, 164–78. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789245714.0013.
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Abstract This chapter presents a wildlife tourism destination attractiveness and sustainability framework based on relevant destination attractiveness attributes and sustainability indicators. The framework was tested at Lake Nakuru National Park (LNNP) in Kenya. Attractiveness was categorized into four dimensions that included wildlife resources, park accessibility, cost of attractions and park image. As the findings indicated, there was direct positive effect of all four dimensions. A relatively low effect was recorded with regard to park image, which is likely to have contributed to low satisfaction experience, future behavioural intentions and park ecological value. In addition, among the repeat visitors' responses, the majority agreed there was increased wildlife disappearance, increased difficulty in sightseeing key wildlife attractions at LNNP, invasive new species within the park, changes in wildlife grazing grounds, infrastructure damage and increased visibility of litter inside the park.
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Ariya, George. "Towards a symbiotic wildlife tourism destination attractiveness and sustainability framework for national parks in Kenya." In Managing visitor experiences in nature-based tourism, 164–78. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789245714.0164.
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Abstract This chapter presents a wildlife tourism destination attractiveness and sustainability framework based on relevant destination attractiveness attributes and sustainability indicators. The framework was tested at Lake Nakuru National Park (LNNP) in Kenya. Attractiveness was categorized into four dimensions that included wildlife resources, park accessibility, cost of attractions and park image. As the findings indicated, there was direct positive effect of all four dimensions. A relatively low effect was recorded with regard to park image, which is likely to have contributed to low satisfaction experience, future behavioural intentions and park ecological value. In addition, among the repeat visitors' responses, the majority agreed there was increased wildlife disappearance, increased difficulty in sightseeing key wildlife attractions at LNNP, invasive new species within the park, changes in wildlife grazing grounds, infrastructure damage and increased visibility of litter inside the park.
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Belcore, Elena, Vincenzo Di Pietra, Nives Grasso, Marco Piras, Francesco Tondolo, Pierclaudio Savino, Daniel Rodriguez Polania, and Anna Osello. "Towards a FOSS Automatic Classification of Defects for Bridges Structural Health Monitoring." In Communications in Computer and Information Science, 298–312. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94426-1_22.
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AbstractBridges are among the most important structures of any road network. During their service life, they are subject to deterioration which may reduce their safety and functionality. The detection of bridge damage is necessary for proper maintenance activities. To date, assessing the health status of the bridge and all its elements is carried out by identifying a series of data obtained from visual inspections, which allows the mapping of the deterioration situation of the work and its conservation status. There are, however, situations where visual inspection may be difficult or impossible, especially in critical areas of bridges, such as the ceiling and corners. In this contribution, the authors acquire images using a prototype drone with a low-cost camera mounted upward over the body of the drone. The proposed solution was tested on a bridge in the city of Turin (Italy). The captured data was processed via photogrammetric process using the open-source Micmac solution. Subsequently, a procedure was developed with FOSS tools for the segmentation of the orthophoto of the intrados of the bridge and the automatic classification of some defects found on the analyzed structure. The paper describes the adopted approach showing the effectiveness of the proposed methodology.
Conference papers on the topic "Low-cost testbed"
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Fergnani, F., and G. Mazzini. "A Low Cost and Flexible Network Testbed." In 2006 3rd Annual IEEE Communications Society on Sensor and Ad Hoc Communications and Networks. IEEE, 2006. http://dx.doi.org/10.1109/sahcn.2006.288552.
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Marques, Paulo, Inene Dias, and Elio Fernandes. "A low cost testbed for synthetic aperture techniques." In 2007 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2007. http://dx.doi.org/10.1109/igarss.2007.4423272.
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Muchtar, Farkhana, Pradeep Kumar Singh, Yugal Kumar, Asma Hanee Ariffin, Suzi Iryanti Fadilah, and Mohd Najwadi Yusoff. "ToMRobot: A Low-Cost Robot for MANET Testbed." In 2018 Fifth International Conference on Parallel, Distributed and Grid Computing (PDGC). IEEE, 2018. http://dx.doi.org/10.1109/pdgc.2018.8745838.
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"Low Cost Adaptive Optics Testbed for Small Telescopes." In International Conference on Photonics, Optics and Laser Technology. SciTePress - Science and and Technology Publications, 2013. http://dx.doi.org/10.5220/0004337900450051.
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Banaszek, Mateusz, Wojciech Dubiel, Jacek Łysiak, Maciej Dębski, Maciej Kisiel, Dawid Łazarczyk, Ewa Głogowska, et al. "1KT: A Low-Cost 1000-Node Low-Power Wireless IoT Testbed." In MSWiM '21: 24th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems. New York, NY, USA: ACM, 2021. http://dx.doi.org/10.1145/3479239.3485708.
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Blom, Koen C. H., Rinse Wester, Andre B. J. Kokkeler, and Gerard J. M. Smit. "Low-cost multi-channel underwater acoustic signal processing testbed." In 2012 IEEE 7th Sensor Array and Multichannel Signal Processing Workshop (SAM). IEEE, 2012. http://dx.doi.org/10.1109/sam.2012.6250551.
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Guntaka, Madhu Lekha, Dharmendra Saraswat, and Petrus Langenhoven. "IoT based low-cost testbed for precision indoor farming." In 2021 ASABE Annual International Virtual Meeting, July 12-16, 2021. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2021. http://dx.doi.org/10.13031/aim.202100617.
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Zubow, Anatolij, and Robert Sombrutzki. "A low-cost MIMO mesh testbed based on 802.11n." In 2012 IEEE Wireless Communications and Networking Conference (WCNC). IEEE, 2012. http://dx.doi.org/10.1109/wcnc.2012.6214352.
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Wilson, Christopher G., and Thaddeus Roppel. "Low-cost wireless mobile ad-hoc network robotic testbed." In 2009 5th International Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities and Workshops. IEEE, 2009. http://dx.doi.org/10.1109/tridentcom.2009.4976222.
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Zhengping Feng, Guiyang Shang, and Lian Lian. "A low-cost testbed of underwater mobile sensing network." In OCEANS 2010 IEEE - Sydney. IEEE, 2010. http://dx.doi.org/10.1109/oceanssyd.2010.5603608.
Full textReports on the topic "Low-cost testbed"
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Ebeling, Carl, and Neil McKenzie. MacTester: A Low-Cost Functional Tester for Interactive Testing and Debugging. Fort Belvoir, VA: Defense Technical Information Center, October 1991. http://dx.doi.org/10.21236/ada241891.
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Rodier, Caroline, Andrea Broaddus, Miguel Jaller, Jeffery Song, Joschka Bischoff, and Yunwan Zhang. Cost-Benefit Analysis of Novel Access Modes: A Case Study in the San Francisco Bay Area. Mineta Transportation Institute, November 2020. http://dx.doi.org/10.31979/mti.2020.1816.
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The first-mile, last-mile problem is a significant deterrent for potential transit riders, especially in suburban neighborhoods with low density. Transit agencies have typically sought to solve this problem by adding parking spaces near transit stations and adding stops to connect riders to fixed-route transit. However, these measures are often only short-term solutions. In the last few years, transit agencies have tested whether new mobility services, such as ridehailing, ridesharing, and microtransit, can offer fast, reliable connections to and from transit stations. However, there is limited research that evaluates the potential impacts of these projects. Concurrently, there is growing interest in the future of automated vehicles (AVs) and the potential of AVs to solve this first-mile problem by reducing the cost of providing these new mobility services to promote access to transit. This paper expands upon existing research to model the simulate the travel and revenue impacts of a fleet of automated vehicles that provide transit access services in the San Francisco Bay Area offered over a range of fares. The model simulates a fleet of AVs for first-mile transit access at different price points for three different service models (door-to-door ridehailing and ridesharing and meeting point ridesharing services). These service models include home-based drop-off and pick-up for single passenger service (e.g., Uber and Lyft), home-based drop-off and pick-up for multi-passenger service (e.g., microtransit), and meeting point multi-passenger service (e.g., Via).
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Redmond, Paul, Seamus McGuinness, and Klavs Ciprikis. A universal basic income for Ireland: Lessons from the international literature. ESRI, December 2022. http://dx.doi.org/10.26504/rs146.
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A universal basic income (UBI) is defined as a universal, unconditional cash payment that is made regularly, is sufficient to live on, is not means tested, carries no work requirements and is paid on an individual basis. This study examines the international evidence on universal basic incomes and identifies key issues for consideration in the design of any UBI pilot for Ireland. Despite the mainstream interest in UBI as a potential policy tool, relatively little is known about the associated consequences of such policies. Even the definition of a UBI appears to be poorly understood and is often misused in the public discourse. Several pilot studies have been recently implemented across different countries. However, some pilot studies depart from the accepted definition of UBI. For example, some are not universal, in that they only target a specific subgroup of the population and/or have eligibility restrictions based on earnings. Others provide a relatively low level of payment, which may fall short of what an individual could reasonably be expected to live on. There are a number of potentially positive impacts associated with a UBI. A universal, unconditional payment could eliminate the stigma associated with welfare receipt. If replacing existing welfare payments, a UBI would also involve lower transaction costs, both on the recipient (in terms of the application procedure) and on Government (in terms of administering the payment). Universal, unconditional payments would also avoid situations where people choose not to work in order to retain means-tested benefits. UBI could give individuals the freedom to turn down or leave insecure, exploitative or low-paid work in pursuit of better or improved work opportunities. In addition, it would mean that persons in informal and often unpaid work, such as childcare and eldercare, which is mostly done by women, receive some compensation for their labour. Empirical results from several pilot studies have found evidence of positive health impacts following the implementation of a UBI. In terms of potential disadvantages, a UBI, by definition, may not target those that are most in need, as a large percentage of recipients will be high-earning individuals. Furthermore, the cost of a UBI is likely to be very expensive, even if other existing benefits (such as unemployment benefits) are no longer required. The net impacts of a UBI on labour supply are unclear, with both positive and negative influences on labour market participation potentially arising as a consequence of a UBI. In this study, we undertake some basic calculations relating to four possible UBI approaches, all of which would involve an unconditional payment to every individual aged over 18 in Ireland.
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Johra, Hicham. Performance overview of caloric heat pumps: magnetocaloric, elastocaloric, electrocaloric and barocaloric systems. Department of the Built Environment, Aalborg University, January 2022. http://dx.doi.org/10.54337/aau467469997.
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Heat pumps are an excellent solution to supply heating and cooling for indoor space conditioning and domestic hot water production. Conventional heat pumps are typically electrically driven and operate with a vapour-compression thermodynamic cycle of refrigerant fluid to transfer heat from a cold source to a warmer sink. This mature technology is cost-effective and achieves appreciable coefficients of performance (COP). The heat pump market demand is driven up by the urge to improve the energy efficiency of building heating systems coupled with the increase of global cooling needs for air-conditioning. Unfortunately, the refrigerants used in current conventional heat pumps can have a large greenhouse or ozone-depletion effect. Alternative gaseous refrigerants have been identified but they present some issues regarding toxicity, flammability, explosivity, low energy efficiency or high cost. However, several non-vapour-compression heat pump technologies have been invented and could be promising alternatives to conventional systems, with potential for higher COP and without the aforementioned refrigerant drawbacks. Among those, the systems based on the so-called “caloric effects” of solid-state refrigerants are gaining large attention. These caloric effects are characterized by a phase transition varying entropy in the material, resulting in a large adiabatic temperature change. This phase transition is induced by a variation of a specific external field applied to the solid refrigerant. Therefore, the magnetocaloric, elastocaloric, electrocaloric and barocaloric effects are adiabatic temperature changes in specific materials when varying the magnetic field, uniaxial mechanical stress, electrical field or hydrostatic pressure, respectively. Heat pump cycle can be built from these caloric effects and several heating/cooling prototypes were developed and tested over the last few decades. Although not a mature technology yet, some of these caloric systems are well suited to become new efficient and sustainable solutions for indoor space conditioning and domestic hot water production. This technical report (and the paper to which this report is supplementary materials) aims to raise awareness in the building community about these innovative caloric systems. It sheds some light on the recent progress in that field and compares the performance of caloric systems with that of conventional vapour-compression heat pumps for building applications.
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Lehotay, Steven J., and Aviv Amirav. Fast, practical, and effective approach for the analysis of hazardous chemicals in the food supply. United States Department of Agriculture, April 2007. http://dx.doi.org/10.32747/2007.7695587.bard.
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Background to the topic: For food safety and security reasons, hundreds of pesticides, veterinary drugs, and environmental pollutants should be monitored in the food supply, but current methods are too time-consuming, laborious, and expensive. As a result, only a tiny fraction of the food is tested for a limited number of contaminants. Original proposal objectives: Our main original goal was to develop fast, practical, and effective new approaches for the analysis of hazardous chemicals in the food supply. We proposed to extend the QuEChERS approach to more pesticides, veterinary drugs and pollutants, further develop GC-MS and LC-MS with SMB and combine QuEChERS with GC-SMB-MS and LC-SMB-EI-MS to provide the “ultimate” approach for the analysis of hazardous chemicals in food. Major conclusions, solutions and achievements: The original QuEChERS method was validated for more than 200 pesticide residues in a variety of food crops. For the few basic pesticides for which the method gave lower recoveries, an extensive solvent suitability study was conducted, and a buffering modification was made to improve results for difficult analytes. Furthermore, evaluation of the QuEChERS approach for fatty matrices, including olives and its oil, was performed. The QuEChERS concept was also extended to acrylamide analysis in foods. Other advanced techniques to improve speed, ease, and effectiveness of chemical residue analysis were also successfully developed and/or evaluated, which include: a simple and inexpensive solvent-in-silicone-tube extraction approach for highly sensitive detection of nonpolar pesticides in GC; ruggedness testing of low-pressure GC-MS for 3-fold faster separations; optimization and extensive evaluation of analyte protectants in GC-MS; and use of prototypical commercial automated direct sample introduction devices for GC-MS. GC-MS with SMB was further developed and combined with the Varian 1200 GCMS/ MS system, resulting in a new type of GC-MS with advanced capabilities. Careful attention was given to the subject of GC-MS sensitivity and its LOD for difficult to analyze samples such as thermally labile pesticides or those with weak or no molecular ions, and record low LOD were demonstrated and discussed. The new approach of electron ionization LC-MS with SMB was developed, its key components of sample vaporization nozzle and flythrough ion source were improved and was evaluated with a range of samples, including carbamate pesticides. A new method and software based on IAA were developed and tested on a range of pesticides in agricultural matrices. This IAA method and software in combination with GC-MS and SMB provide extremely high confidence in sample identification. A new type of comprehensive GCxGC (based on flow modulation) was uniquely combined with GC-MS with SMB, and we demonstrated improved pesticide separation and identification in complex agricultural matrices using this novel approach. An improved device for aroma sample collection and introduction (SnifProbe) was further developed and favorably compared with SPME for coffee aroma sampling. Implications, both scientific and agricultural: We succeeded in achieving significant improvements in the analysis of hazardous chemicals in the food supply, from easy sample preparation approaches, through sample analysis by advanced new types of GC-MS and LCMS techniques, all the way to improved data analysis by lowering LOD and providing greater confidence in chemical identification. As a result, the combination of the QuEChERS approach, new and superior instrumentation, and the novel monitoring methods that were developed will enable vastly reduced time and cost of analysis, increased analytical scope, and a higher monitoring rate. This provides better enforcement, an added impetus for farmers to use good agricultural practices, improved food safety and security, increased trade, and greater consumer confidence in the food supply.
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Pullammanappallil, Pratap, Haim Kalman, and Jennifer Curtis. Investigation of particulate flow behavior in a continuous, high solids, leach-bed biogasification system. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600038.bard.
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Recent concerns regarding global warming and energy security have accelerated research and developmental efforts to produce biofuels from agricultural and forestry residues, and energy crops. Anaerobic digestion is a promising process for producing biogas-biofuel from biomass feedstocks. However, there is a need for new reactor designs and operating considerations to process fibrous biomass feedstocks. In this research project, the multiphase flow behavior of biomass particles was investigated. The objective was accomplished through both simulation and experimentation. The simulations included both particle-level and bulk flow simulations. Successful computational fluid dynamics (CFD) simulation of multiphase flow in the digester is dependent on the accuracy of constitutive models which describe (1) the particle phase stress due to particle interactions, (2) the particle phase dissipation due to inelastic interactions between particles and (3) the drag force between the fibres and the digester fluid. Discrete Element Method (DEM) simulations of Homogeneous Cooling Systems (HCS) were used to develop a particle phase dissipation rate model for non-spherical particle systems that was incorporated in a two-fluid CFDmultiphase flow model framework. Two types of frictionless, elongated particle models were compared in the HCS simulations: glued-sphere and true cylinder. A new model for drag for elongated fibres was developed which depends on Reynolds number, solids fraction, and fibre aspect ratio. Schulze shear test results could be used to calibrate particle-particle friction for DEM simulations. Several experimental measurements were taken for biomass particles like olive pulp, orange peels, wheat straw, semolina, and wheat grains. Using a compression tester, the breakage force, breakage energy, yield force, elastic stiffness and Young’s modulus were measured. Measurements were made in a shear tester to determine unconfined yield stress, major principal stress, effective angle of internal friction and internal friction angle. A liquid fludized bed system was used to determine critical velocity of fluidization for these materials. Transport measurements for pneumatic conveying were also assessed. Anaerobic digestion experiments were conducted using orange peel waste, olive pulp and wheat straw. Orange peel waste and olive pulp could be anaerobically digested to produce high methane yields. Wheat straw was not digestible. In a packed bed reactor, anaerobic digestion was not initiated above bulk densities of 100 kg/m³ for peel waste and 75 kg/m³ for olive pulp. Interestingly, after the digestion has been initiated and balanced methanogenesis established, the decomposing biomass could be packed to higher densities and successfully digested. These observations provided useful insights for high throughput reactor designs. Another outcome from this project was the development of low cost devices to measure methane content of biogas for off-line (US$37), field (US$50), and online (US$107) applications.
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Gerstl, Zev, Thomas L. Potter, David Bosch, Timothy Strickland, Clint Truman, Theodore Webster, Shmuel Assouline, Baruch Rubin, Shlomo Nir, and Yael Mishael. Novel Herbicide Formulations for Conservation-Tillage. United States Department of Agriculture, June 2009. http://dx.doi.org/10.32747/2009.7591736.bard.
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The overall objective of this study was to develop, optimize and evaluate novel formulations, which reduce herbicide leaching and enhance agronomic efficacy. Numerous studies have demonstrated that CsT promotes environmental quality and enhances sustainable crop production, yet continued use of CsT-practices appears threatened unless cost effective alternative weed control practices can be found. The problem is pressing in the southern portion of the Atlantic Coastal Plain region of the eastern USA where cotton and peanut are produced extensively. This research addressed needs of the region’s farmers for more effective weed control practices for CsT systems. HUJI: CRFs for sulfentrazone and metolachlor were developed and tested based on their solubilizion in cationic micelles and adsorption of the mixed micelles on montmorillonite. A better understanding of solubilizing anionic and nonionic organic molecules in cationic micelles was reached. Both CRFs demonstrated controlled release compared to the commercial formulations. A bioassay in soil columns determined that the new sulfentrazone and metolachlor CRFs significantly improve weed control and reduced leaching (for the latter) in comparison with the commercial formulations. ARO: Two types of CRFs were developed: polymer-clay beads and powdered formulations. Sand filter experiments were conducted to determine the release of the herbicide from the CRFs. The concentration of metolachlor in the initial fractions of the effluent from the commercial formulation reached rather high values, whereas from the alginate-clay formulations and some of the powdered formulations, metolachlor concentrations were low and fairly constant. The movement of metolachlor through a sandy soil from commercial and alginate-clay formulations showed that the CRFs developed significantly reduced the leaching of metolachlor in comparison to the commercial formulation. Mini-flume and simulated rainfall studies indicated that all the CRFs tested increased runoff losses and decreased the amount of metolachlor found in the leachate. ARS: Field and laboratory investigations were conducted on the environmental fate and weed control efficacy of a commercially available, and two CRFs (organo-clay and alginate-encapsulated) of the soil-residual herbicide metolachlor. The environmental fate characteristics and weed control efficacy of these products were compared in rainfall simulations, soil dissipations, greenhouse efficacy trials, and a leaching study. Comparisons were made on the basis of tillage, CsT, and conventional, i.e no surface crop residue at planting (CT). Strip-tillage (ST), a commonly used form of CsT, was practiced. The organo-clay and commercial metolachlor formulations behaved similarly in terms of wash off, runoff, soil dissipation and weed control efficacy. No advantage of the organo-clay over the commercial metolachlor was observed. Alginate encapsulated metolachlor was more promising. The dissipation rate for metolachlor when applied in the alginate formulation was 10 times slower than when the commercial product was used inferring that its use may enhance weed management in cotton and peanut fields in the region. In addition, comparison of alginate and commercial formulations showed that ST can effectively reduce the runoff threat that is commonly associated with granular herbicide application. Studies also showed that use of the alginate CRF has the potential to reduce metolachlor leaching. Overall study findings have indicated that use of granular herbicide formulations may have substantial benefit for ST-system weed management for cotton and peanut production under Atlantic Coastal Plain conditions in the southeastern USA. Commercial development and evaluation at the farm scale appears warranted. Products will likely enhance and maintain CsT use in this and other regions by improving weed control options.
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Pesis, Edna, Elizabeth J. Mitcham, Susan E. Ebeler, and Amnon Lers. Application of Pre-storage Short Anaerobiosis to Alleviate Superficial Scald and Bitter Pit in Granny Smith Apples. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7593394.bard.
Full textAbstract:
There is increased demand for high quality fruit produced and marketed with reduced chemical inputs to minimize toxic effects on human health and the environment. Granny Smith (GS) apple quality is reduced by two major physiological disorders, superficial scald and bitter pit (BP). These disorders cause great loss to apple growers worldwide. Superficial scald is commonly controlled by chemical treatments, mainly the antioxidant diphenylamine (DPA) and/or the ethylene action inhibitor, 1-methylcyclopropene (1–MCP). Both chemicals are ineffective in controlling bitter pit incidence. We proposed to investigate the beneficial use of non-chemical, abiotic stress with low O2 (LO2) applied for 10d at 20°C on GS apple fruit. During the project we expanded the treatment to more apple cultivars, Golden Delicious (GD) and Starking Delicious (SD) and another pome fruit, the pear. Apple and pear have similar physiological disorders that develop during cold storage and we examined if the LO2 treatment would also be effective on pear. Application of 0.5% LO2 atmosphere for 10d at 20°C or 500ppb 1-MCP at 20°C prior to cold storage at 0°C, was effective in reducing superficial scald in GS apple. Moreover, LO2 pretreatment was also effective in reducing bitter pit (BP) development in California GS and Israeli GD and SD apples The BP symptoms in GS from California were much more prominent, so the effect of LO2 was more dramatic than the effect on the Israeli cvs. GD and SD, nevertheless the LO2 treatment showed the same trend in all cultivars in reducing BP. The LO2 and 1-MCP -treated fruit exhibited lower levels of ethylene, - farnesene and its oxidation product, 6-methyl-5-hepten-2-one (MHO), as determined by SPME/GC-MS analysis. In addition, LO2 pretreatment applied to California Bartlett or Israeli Spadona pears was effective in reducing superficial scald, senescent scald and internal breakdown after 4 m of cold storage at 0°C. For GS apple, low-temperature storage resulted in oxidative stress and chilling injury, caused by increased production of superoxide anions which in turn led to the generation of other dangerous reactive oxygen species (ROS). Using confocal laser-scanning microscopy and H2O2 measurements of apple peel, we observed ROS accumulation in control fruit, while negligible amounts were found in LO2 and 1-MCP treated fruit. Gene-expression levels of ROS-scavenging enzymes were induced by the various pretreatments: catalase was induced by LO2 treatment, whereas Mn superoxide dismutase was induced by 1-MCP treatment. We assume that LO2 and 1-MCP pretreated fruit remained healthier due to reduced production of ethylene and reactive oxygen substances, such as MHO, during cold storage. The LO2-treated apple exhibited greener peel and firmer fruit after 6 m of cold storage, and the fruit had high crispiness leading to high taste preference. In both pear cultivars, the LO2 treatment led to a reduction in internal breakdown and browning around the seed cavity. We tested the LO2 pre-storage treatment on a semi-commercial scale that would be applicable to a small organic grower by sealing the fruit within the plastic field bins. The treatment was most effective with a continuous flow of nitrogen through the bins; however, a single 6 hour flush of nitrogen was also fairly effective. In addition, we determined that it was very important to have the oxygen levels below 0.5% for approximately 10 days to achieve good scald control, not counting the time required to reduce the oxygen concentration. Our LO2 technology has been proven in this project to be effective in reducing several physiological disorders developed in pome fruit during cold storage. We hope that our non-chemical treatment which is friendly to the environment will be used in the near future for the organic apple and pear industry. The next step should be an analysis of the cost-benefits and commercial feasibility.
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Lahav, Ori, Albert Heber, and David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, March 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
Full textAbstract:
The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Attracting youth to voluntary counseling and testing services in Uganda. Population Council, 2004. http://dx.doi.org/10.31899/hiv15.1009.
Full textAbstract:
Little is known about the use of voluntary counseling and testing (VCT) by youth, a group that comprises more than half of those newly infected with HIV. An exploratory study conducted in Nairobi, Kenya, and Kampala and Masaka in Uganda revealed that young people want information, confidentiality, low-cost HIV testing, and friendly, professional counseling. Two facilities in Kampala, the AIDS Information Center (AIC) and Naguru Teenage Information and Health Center (NTIHC), implemented new youth-oriented strategies to increase VCT utilization and satisfaction with services among young people. In 2001, AIC established a youth corner behind the regular adult clinic with a separate gate so youth could enter in privacy. In 2002, NTIHC began offering VCT two days per week. This brief presents findings from exit interviews conducted with youth 14–21 years old leaving services at AIC and NTIHC. It also draws on in-depth interviews with exit interview participants and on focus groups conducted with tested and untested youth.