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1
Edmark, Marcus, and Olle Benzler. "Measurement Method Analysis of Photonic CO2 Sensor." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200580.
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Zhu, Yongming [Verfasser]. "CO2 sensor based on lithium ion conductor / Yongming Zhu." Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019813350/34.
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Válek, Vít. "Flexibilní bezdrátový systém pro měření CO2 v budově." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442452.
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Monitoring of the carbon dioxide concentration in the building is carried out for several reasons. One is to ensure hygiene conditions. With the advent of Bluetooth 5.0 came the support of mesh network technology, which is defined by the Bluetooth Mesh standard. By implementing this standard, we can create an extensive network of devices monitoring the concentration of carbon dioxide in the building. Based on the monitored concentration, we can control the air conditioning and ventilation of the spaces, ensuring that the hygiene conditions are met. Thanks to the compatibility of Bluetooth Mesh with Bluetooth Low Energy, it is possible to access individual nodes, e.g. from a mobile phone. The aim of this work is to design and implement a measuring system whose elements will communicate with each other using Bluetooth Mesh wireless technology.
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Nygård, Skalman Jonas. "CO2 Sensor Core on FPGA : ASIC prototyping and cost estimates." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35963.
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Demand of CO2 gas sensors is expected to continue to increase in the foreseeable future, due to an increasing awareness of air pollution and fossil fuel emissions. A truly low cost and accurate NDIR sensor has the potential of greatly benefiting the environment by an increased human awareness due to CO2 measurements. In the objective to reach these goals, a CO2 sensor core on an ASIC needs to be investigated. In this study an ASIC prototype design is tested on an FPGA and evaluated towards logic resource requirements, power analysis and estimated cost impacts towards a full ASIC. The results show that a potential ASIC implementation would have a very small cost impact on a full system design if the use of a preexisting ASIC design is utilized. Using a manufacturing process of 180 nm, the total logic implementation would require between 0.54-0.76 mm2. The cost impact of such a logic area would be around $0.025 USD per chip. The power consumption of the logical part would also be very small when compared to the various analog components of a full system design.
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Schaeffer, Robson Dagmar. "Estudo e desenvolvimento de um sensor de CO2 de baixo custo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2004. http://hdl.handle.net/10183/4199.
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Este trabalho descreve um estudo e desenvolvimento de um sensor de dióxido de carbono (CO2), de baixo custo, para monitoramento da qualidade do ar em ambientes climatizados. O sensor aqui proposto baseia-se na técnica de absorção em infravermelho não dispersivo (NDIR). Este trabalho avalia alguns métodos já empregados e propõe um modelo alternativo visando uma solução de baixo custo que possa ser incorporada a sistemas de monitoramento e/ou condicionamento existentes, permitindo o controle do teor de CO2. A metodologia inclui o estudo dos diferentes tipos de sensores de CO2, a seleção da técnica mais apropriada para medição, o estudo das alternativas para implementação da técnica selecionada, o desenvolvimento, testes e avaliações da solução. Especificamente desenvolveu-se uma solução em termos de sensor de CO2 que utiliza componentes comerciais, sendo facilmente reprodutível e de custo reduzido. O sensor desenvolvido tem faixa de medição entre 330 a mais de 10000 ppm, com resolução estimada em torno de 20 a 30 ppm, com erro em relação ao padrão menor que 10% da medição ou 150 ppm,o que for maior.
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Kuutmann, Hanna, and Emelie Rosén. "Smartphone Capnography : Evaluation of the concept and the associated CO2 indicating sensor." Thesis, KTH, Medicinsk teknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152640.
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Smartphone capnography is a new concept for respiratory monitoring using a colorimetric sensor in combination with a smartphone and an Android application. Compared to using an infrared spectrophotometric carbon dioxide analyzer (IR-analyzer), the gold standard for respiratory carbon dioxide monitoring, smartphone capnography offers a cheaper and less bulky solution. This master thesis evaluates the performance of smartphone capnography and the colorimetric sensor engineered for this concept. Three different techniques (side stream, shunt stream and main stream) were tested. Additionally, an iPhone application was developed as a proof of concept when using an iPhone for smartphone capnography. An experimental set-up simulating human breathing was assembled and measurements, at different breathing rates (6-30 breaths/min) and carbon dioxide levels (2-7vol%), were performed with an IR-analyzer as reference. Results showed that capnograms from smartphone capnography was comparable to those from the IR-analyzer and that the approximate accuracy was ±0.25vol% for up to 6 days of use. Results strongly motivate further elaboration of the concept and the three different techniques for measuring.<br>”Smartphone capnography” är ett nytt koncept för att monitorera andning. Principen är en kombination av en kolorimetrisk sensor, en smartphone samt en Androidapplikation. Jämfört med den dominerande tekniken, en IR-spektrofotometrisk koldioxidanalysator (IR-analysator), så är “smartphone capnography” både billigare och mindre skrymmande. Detta examensarbete utvärderar konceptet ”smartphone capnography” och en kolorimetrisk sensor speciellt utvecklad för ändamålet. Tre olika tekniker (side stream, shunt stream och main stream) har utvärderats. Slutligen utvecklades en iPhoneapplikation för att visa att konceptet ”smartphone capnography” kan användas även med denna typ av smartphone. Utvärderingen bestod i att göra mätningar i en experimentell uppställning som simulerar andning. Mätningar gjordes vid varierande andningsfrekvenser (6-30 andetag/min) och koldioxidnivåer (2-7vol%). Mätdata från ”smartphone capnography” jämfördes med mätdata från en IR-analysator. Resultaten visar att kapnogram från ”Smartphone capnography” är jämförbara med kapnogram från IR-analysatorn och att den uppskattade noggrannheten är ±0,25vol% för upp till 6 dagars användning. De goda resultaten motiverar fortsatt utveckling av konceptet smartphone capnography samt de olika mätteknikerna.
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Zuo, Ziwei. "Fabrication of intensity-based Long-Period-Gratings fiber sensor with CO2 Laser." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54599.
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This thesis investigates the fabrication technique and procedures for producing long period grating (LPG) fiber sensors with point-by-point irradiation under a CO2 laser beam. The type of fiber sensor under examination is desirable to be highly sensitive to the variation of the thickness and refractive index of a thin film deposited on the LPGs, making it a promising candidate as a core sensor component in a biosensor system developed for detection and verification of pathogenic bacteria, such as Methicillin-resistant Staphylococcus aureus (MRSA), Francisella tularensis, and so on.
We have previously demonstrated that a UV-induced long-period-grating (LPG) based fiber sensor is extremely sensitive to small variation of refractive index (RI) and thickness of the surrounding medium. In this thesis, we will present a CO2 laser and step- stage system that operate automatically under control of a Matlab program to inscribe LPGs with desired grating period and fabrication conditions.
Examples of CO2 laser induced LPGs have been found to exhibit high sensitivity, with transmissive power attenuation of more than 15 dB at the resonant peak of 1402 nm under deposition of Ionic Self-Assembled Monolayer (ISAM) thin film that is around 50 nm in thickness. When tuned to its maximum sensitivity region, this LPG has shown a transmission power reduction of 79% with the deposition of only 1 bilayer of ISAM thin film at the monitored wavelength. This result is comparable in sensitivity with the UV-induced LPGs, yet with the advantage of lower fabrication cost and simplified fabrication procedure.<br>Master of Science
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Bellancini, Michele <1989>. "Development and Validation of a CO2 Sensor for Extra Corporeal Life Support Applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9755/1/Development_and_Validation_of_a_CO2_Sensor_for_Extracorporeal_Life_Support_Applications.pdf.
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Measurement of carbon dioxide (CO2) in medical applications is a well-established method for monitoring patient’s pulmonary function in a noninvasive way widely
used in emergency, intensive care, and during anaesthesia.
Even in extra corporeal life support (ECLS) applications, such as Extra corporeal Carbon Dioxide Removal (ECCO2R), Extra corporeal Membrane Oxygenation (ECMO), and cardiopulmonary by-pass (CPB), measurement of the CO2 concentration in the membrane oxygenator exhaust gas is proven to be useful to evaluate the treatment progress as well as the performance of the membrane oxygenator.
This thesis presents the development of a new optical sensor specifically designed for the measurement of CO2 concentration in the oxygenator exhaust gas. The project’s goal is to develop a sensor with Technology Readiness Level of 9, meaning that the developed sensor
shall also be proven and validated in the operational environment.
Initially, to allow a better comprehension of the application for which the developed sensor is intended, an overview of the ECLS application scenario is given, describing the key components of an ECLS device, as well as the most used ECLS procedures. Further, considerations about the importance of CO2 concentration measurement in the membrane oxygenator exhaust gas are reported. Then, the measurement principle for carbon dioxide concentration is described, as well as state-of-the-art technologies used in this field. Moreover, design requirements that the developed sensor should meet are analyzed and disclosed. Sensor architecture is described, focusing on the method implemented to prevent condensation of the water vapour in the membrane oxygenator’s exhaust gas. Effects of temperature on the sensor optical elements performance are addressed through theoretical and experimental analysis, and methods to avoid signal–temperature dependency are described. Finally, the results of the test performed on the developed sensor both in-vitro and in-vivo conditions are reported and discussed.
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Lee, Chong-Hoon. "Study of reversible electrode reaction and mixed ionic and electronic conduction of lithium phosphate electrolyte for an electrolchemical co2 gas sensor." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1073047249.
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Borkar, Chirag. "Development of Wireless Sensor Network System for Indoor Air Quality Monitoring." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc177181/.
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This thesis describes development of low cost indoor air quality (IAQ) monitoring system for research. It describes data collection of various parameters concentration present in indoor air and sends data back to host PC for further processing. Thesis gives detailed information about hardware and software implementation of IAQ monitoring system. Also discussed are building wireless ZigBee network, creating user friendly graphical user interface (GUI) and analysis of obtained results in comparison with professional benchmark system to check system reliability. Throughputs obtained are efficient enough to use system as a reliable IAQ monitor.
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Yoon, Junro. "A Study of Interface Reaction of Li0.35La0.55TiO3-Li2CO3 and Its Effect on Potentiometric CO2 Gas Sensors." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354666091.
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Peňák, Vlastimil. "Návrh kontrolního přípravku pro plastový výrobek interiéru osobního vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241711.
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This diploma thesis deals with the development, disign and manufacturing inspection device that is able to detect the presence of components in the assembly of the plastic molding. Evaluation of information are indicated by the operator device and sent for further processing. Rechecked product will be marked with a uniquemark.
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Lander, Jasmine. "Cost-efficient approaches to measure carbon dioxide (CO2) under different environmental factors such as temperature and humidity using mini loggers." Thesis, Linköpings universitet, Institutionen för tema, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165993.
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Fluxes of carbon dioxide (CO2), being a major greenhouse gas, are of great importance to understand and monitor. Findings have shown that while CO2 emissions enhanced by humans triggered the greenhouse gas effect, several significant CO2 fluxes in nature that are climate sensitive may still be poorly constrained, especially those from inland waters and its surrounding soils and sediments. This including different processes such as decomposers degrading organic material. At present, direct measurements of CO2 from soils, waters or CO2 concentrations in surface water, are typically labour intensive or require costly equipment. Therefore, small inexpensive CO2 mini loggers, originally made for indoor air quality monitoring, are for this project being developed further for field use, as a convenient equipment to measure CO2 emissions. However, a requirement is that the mini loggers are stable and robust against interference by other air components, including water vapour, and physical factors such as temperature. Therefore, the mini loggers were for this project studied further under different environmental conditions such as temperature and humidity in a controlled environment. The results were analysed using multiple regression analysis where the CO2 concentration (CO2), measured by the LGR instrument, versus the logger IR signal (IR), temperature (T) and relative humidity (RH) were studied. Unlike some previous studies, this project studied a large CO2 concentration interval (400 – 10 000 ppm). The results show that there was a strong regression for IR versus CO2. The regression for both RH and the T was on the other hand very weak. However, there were factors that could have affected the mini logger. This since it was noticed that the mini loggers’ ability to calculate the CO2 concentration was worsened when the humidity was increased during the experiments. It is believed that the cause was condensed water, gathering in the inner parts of the mini logger. This because the sensor chamber had a lower temperature than the hot air entering the sensor chamber from the humidity bottle, together with the CO2, leading to condensation. Hence, prevention of condensation inside the measurement cell is important. However, the results from the analysis shows that the factors; RH and T do not need to be taken into account when studying the CO2 concentration over a larger interval, as long as the conditions are not condensing.
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ILIE, Ana Maria Carmen. "Smart Sensor Technology for Environmental Monitoring Applications." Doctoral thesis, Università degli studi di Ferrara, 2018. http://hdl.handle.net/11392/2487882.
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Research Project focused on developing innovative devices using the low-cost sensors to obtain the concentrations of greenhouse gases (GHGs) such as carbon dioxide (CO2) and methane (CH4) as well as obtain a good water quality as a 2nd treatment in the Wastewater Treatment Plant. In addition to sensor calibration, the multi-parameter monitor prototype were tested in several contexts: a) Laboratory scale with natural soil columns, to figure out the sensor response under controlled conditions, calibration and validation; b) Field scale in many geological contexts, for Air-Soil quality (methane and carbon dioxide measurements): Natural Gas Storage Site in Minerbio, Italy; Drilling and Hydraulic Fracturing activities in Greeley, CO, USA; for Water Quality: Wastewater Treatment Plant in Algarve, Portugal. The monitoring system provided a huge set of data for which can be used statistical analysis, management and processing (Big DATA). The source identification of greenhouse gas emissions is identified in several IPCC reports that climate change is the major emergency for the socio / economic / environmental equilibrium of Earth planet. No outliers were identified as methane gas concentrations at Minerbio gas storage site, Italy and at Hydraulic activities in Greeley, Colorado. The soil column experiments for infiltration basins in the Wastewater treatment plant in Algarve, Portugal, gave us good results, the water quality was improved after the 2nd treatment. The low-cost sensors (gas – water) gave as a good calibration and validation with r2 coefficient of correlation of 0.70 – 0.96.<br>Il progetto di ricerca si è concentrato sullo sviluppo di dispositivi innovativi utilizzando i sensori a basso costo per ottenere le concentrazioni di gas (GHG) quali anidride carbonica (CO2) e metano (CH4) e ottenere una buona qualità dell'acqua come secondo trattamento nelle acque reflue nell’impianto di trattamento. Oltre alla calibrazione del sensore, il prototipo di monitoraggio multiparametro è stato testato in diversi contesti: a) Nel laboratorio con colonne di terreno naturali, suoli, per determinare la risposta del sensore in condizioni controllate, calibrazione e validazione; b) Scala di campo in molti contesti geologici, per la qualità Aria-suolo (misure di metano e anidride carbonica, radon) nel sito di stoccaggio di gas naturale a Minerbio, Italia; Attività di perforazione e fratturazione idraulica in Greeley, Colorado, USA; per la qualità dell'acqua: impianto di trattamento delle acque reflue in Algarve, Portogallo. Il sistema di monitoraggio ha fornito un enorme set di dati per i quali è stato possibile utilizzare analisi statistiche, gestione ed elaborazione (Big DATA). L'identificazione della fonte delle emissioni di gas è stata identificata in diversi rapporti dell'IPCC secondo cui i cambiamenti climatici rappresentano l'emergenza principale per l'equilibrio socio / economico / ambientale del pianeta Terra. Non sono stati identificati valori anomali come concentrazioni di gas metano nel sito di stoccaggio di Minerbio (Italia) e nelle attività di perforazione in Greeley, Colorado, USA. Gli esperimenti con la colonna di terreno per i bacini di infiltrazione nell'impianto di trattamento delle acque reflue in Algarve, in Portogallo, ci hanno dato buoni risultati, la qualità dell'acqua è stata migliorata dopo il 2 ° trattamento. I sensori a basso costo (gas - acqua) per la qualita’ dell’aria e del suolo, hanno fornito una buona calibrazione e validazione con coefficiente di correlazione r2 di 0,70 - 0,96.
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Machýček, David. "Konstrukce bioinkubátoru pro transport buněčných kultur." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230378.
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In a research part, this diploma thesis deals with dividing incubators into groups according to their kind of use. From the groups biological incubators have been chosen to describe their construction, to explain possibilities of doing sampling and temperature and CO2 control. The research part is concluded by an overview of biological transport incubators for a transfer of cell cultures. In the part of the thesis which deals with a new construction solution some variations are suggested. The most suitable variation has been chosen after a structural technological description, and it is further described in a constructional solution. The frame of the incubator is made from aluminium alloy and is controlled by FEM. There are individual structural nodes being explained and visualised step by step in the construction solution. In the end of the construction solving some information about making the construction and prices of all continuing manufacture are stated.
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ABATE, MOLLA TADESSE. "Supercritical CO2 technology in resource-effective production of functional and smart textiles." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2858353.
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Bučko, Ondrej. "Efektivní řízení technologií budov s důrazem na měření vlhkosti a koncentrace CO2." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442540.
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The diploma thesis deals with automated measurement of humidity and CO2 concentration inside buildings. Results of this measurement form the input parameters for the effective management of technologies reducing the energy performance of buildings. In the introduction, the issue of indoor air quality of buildings and indicators characterizing this quality are approached. The technical part of the thesis consists of making a measuring device which contains two prototype sensors provided by Teco Inc. with online access to measured data. The measurement of relative humidity, CO2 concentration and temperature in the interior of the building with the made device is compared with commercially available devices for measuring selected parameters. For unambiguous interpretation of online data, the virtual machine with an online database is configured for the created measuring device. The possibilities of using the prepared measuring device to achieve a reduction in the energy performance of buildings are discussed in the final part.
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Sebem, Renan. "Customização de sensibilidade de sensores a redes de período longo em fibras ópticas monomodo padrão e aplicações." Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/2086.
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Previous issue date: 2015-09-21<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>This work explores the potential and shows the implementation of the long period gratings as refractive index sensors. It is proposed a sensor design where the refractive index sensitivity is improved. The design includes the use of the sensor with simple and low cost interrogation. Several manufacturing parameters are investigated and the process is enhanced to meet the design specifications, and also to obtain repeatability in the process. New ideas were proposed to manufacture tilted gratings and to control the index modulation duty cycle in a practical way with inexpensive equipment. The inscription of the fiber sensor is made by CO2 laser, point to point, with a uniform index modulation. The gratings were interrogated by an optical spectrum analyzer and also by edge filter demodulation in the 1550 nm region through an electronic board, developed in this work with automatic normalization of the signal. Results show that the refractive index sensitivity is influenced by several design and manufacturing parameters of the fiber grating. Performed experiments show a considerable increase in the refractive index sensitivity of the grating.<br>Este trabalho explora o potencial e demonstra a implementação das redes de período longo em fibra como sensores de índice de refração. É proposto um projeto do sensor em que a sensibilidade ao índice de refração é aperfeiçoada. O projeto contempla a utilização do sensor com interrogação de maneira simples e de baixo custo. Diversos parâmetros de fabricação são investigados e o processo é aprimorado para atingir as especificações de projeto, e também a fim da obtenção de repetibilidade no processo. Novas ideias foram propostas para fabricação de redes inclinadas e para o controle do duty cycle da modulação de índice da rede de maneira prática com equipamentos de baixo custo. A fabricação do sensor em fibra é feita através de laser de CO2, ponto a ponto, e com modulação de índice uniforme. As redes foram interrogadas através de analisador de espectro óptico e também por demodulação de borda de filtro na região de 1550 nm através de uma placa eletrônica, desenvolvida neste trabalho com normalização automática do sinal. Resultados mostram que a sensibilidade ao índice de refração é influenciada por alguns parâmetros de projeto e fabricação da rede em fibra. Experimentos realizados mostraram um aumento considerável na sensibilidade da rede ao índice de refração.
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Aiyar, Avishek R. "Microfabrication of a MEMS piezoresistive flow sensor - materials and processes." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24696.
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Canning, Anna [Verfasser], Arne [Akademischer Betreuer] Körtzinger, and Bernhard [Gutachter] Wehrli. "Greenhouse gas observations across the Land-Ocean Aquatic Continuum: Multi-sensor applications for CO2, CH4 and O2 measurements / Anna Canning ; Gutachter: Bernhard Wehrli ; Betreuer: Arne Körtzinger." Kiel : Universitätsbibliothek Kiel, 2020. http://d-nb.info/1211649261/34.
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Lan, Lijuan [Verfasser], Jia [Akademischer Betreuer] Chen, Jia [Gutachter] Chen, and Mark [Gutachter] Wenig. "Development of a CO2 sensor using TDLAS-WMS and its application for emission analysis in Munich / Lijuan Lan ; Gutachter: Jia Chen, Mark Wenig ; Betreuer: Jia Chen." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1212178173/34.
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Chahal, Radwan. "Capteurs optiques en fibres de verre de chalcogénure dopées terres rares appliqués à la surveillance du stockage géologique de CO2." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S066/document.
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L'augmentation des émissions de CO2 entraîne un réchauffement de la planète préjudiciable aux équilibres écologiques terrestres. Dans ce contexte, le stockage de CO2 dans des formations géologiques terrestres et sous-marines se pose comme un moyen intéressant de limiter les conséquences de ces émissions. Cependant cette solution nécessite une surveillance continue afin de détecter d'éventuelles fuites au niveau d'une zone de stockage. Les travaux de thèse présentés concernent le développement d'un capteur optique en fibre de chalcogénures pour la détection de CO2 gazeux fonctionnant dans le moyen infrarouge. Cette détection est basée sur un phénomène de luminescence, jouant le rôle de source déportée et partiellement absorbée en présence de CO2. Le développement de ces fibres optiques a demandé un important travail en sciences des matériaux et en caractérisation spectroscopique. Un prototype a été fabriqué et utilisé avec succès sur le terrain lors de campagnes de mesure menées in-situ<br>The increase of CO2 emissions causes global warming harmful to ecological balances in earth. In this context, CO2 storage in geological formations is an interesting way to limit the consequences of these emissions. However, this solution requires continuous monitoring to detect possible leaks at storage area. The presented work involves the development of an optical fiber sensor based on chalcogenide glasses for the CO2 gas detection operating in the infrared. This detection is based on a luminescent phenomenon, acts as a remote source and partly absorbed in the presence of CO2. The development of these fiber optic asked important work in materials science and spectroscopic characterization. A prototype was manufactured and successfully used in the field during measurement campaigns in situ
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Лазаренко, С. М. "Програмно-апаратна реалізація припливно витяжної установки й управління елементами вентиляції як частина системи «розумного дому»". Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/22992.
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Лазаренко, С. М. Програмно-апаратна реалізація припливно витяжної установки й управління елементами вентиляції як частина системи «розумного дому» : дипломна робота : 123 - Комп’ютерна інженерія / С. М. Лазаренко ; керівник роботи Є. В. Риндич ; НУ "Чернігівська політехніка", кафедра Інформаційних та комп’ютерних систем. - Чернігів, 2021. - 98 с.<br>Роботу присвячено розгляду і розробці системи припливно-витяжної
вентиляції з рекуперацією тепла і вологи у приватному будинку як частини
системи «розумного дому». Створено класифікації функціональних і
структурних особливостей систем «розумного дому» й описано комплекси
функцій, які здатні виконувати його різноманітні підсистеми.
«Розумний дім» розглядається в роботі як високотехнологічне
устаткування сучасного житлового будинку, система елементів
комп’ютерного управління сукупністю відповідних підсистем, що разом
реалізують низку функцій, пов’язаних із створенням безпечних і комфортних
умов проживання людини.
Для створення програмно-апаратної частини системи припливно витяжної вентиляції обрано мікропроцесорну плату Arduino і систему
автоматизації «MajorDoMo», з дротовим способом підключення.
Передбачено, що контролер працюватиме як в автоматичному, так і в
ручному режимах. Файли розробленої програми, пов'язані з різними
елементами обладнання, було вирішено підключати індивідуально.
У межах механічної частини системи вентиляції у приватному будинку
вирішено використати систему з примусовим спонуканням, до яких входить
вентилятор, гексагональний і ентальпійний теплообмінники, повітроводи та
вентиляційні решітки. Було створено корпус рекупераційної установки,
виготовлено шумоглушники і придбано заслінки для регулювання потоку
повітря сервоприводами.
Апаратну частину системи було вкомплектовано контролером Arduino
Mega 2560 Rev3, платою розширення W5500 Ethernet Shield, сукупністю
датчиків, сервоприводів, реле, димерів, LCD екраном, енкодером /
потенціометром тощо. Для її монтажу було створено схему розташування
пристроїв на плані приватного будинку.
Роботу системи припливно-витяжної вентиляції було представлено на
основі макетної плати, для створення якої використано сервоприводи та
датчики. Перевірка показала, що все обладнання працює згідно з
передбаченими для нього алгоритмами, а розроблена програма може
ефективно застосовуватися для експлуатації системи припливно-витяжної
вентиляції у приватному будинку<br>The paper focuses on the review and analysis of the supply-and-exhaust
ventilation with the recovery of heat and moisture in a detached house as a part of the
Intelligent building system. The classification of functional and structural features of
Intelligent building systems is presented, and complexes of functions which their
various subsystems are able to fulfil are described.
In the paper the Intelligent building is viewed as state-of-art equipment of a
modern detached house, a software system controlling the work of the relevant
subsystems which jointly carry out a set of functions, connected with the provision
of safe and comfortable living conditions for the residents of the house.
A microprocessor card Arduino and MajorDoMo automation system with
wired connection were chosen to create the software and hardware parts of the
supply-and-exhaust ventilation. The controller is supposed to work in both automatic
and manual modes. Software files related to different hardware components are
connected independently.
A decision was made that an induced natural ventilation system comprising
a fan, hexagonal and enthalpy heat exchangers, air ducts and air grids would be
used in the mechanical part of the detached house ventilation. The frame of the
recovery facility and mufflers were constructed, and shutters were purchased for
servodrives to be able to regulate the air flow.
The hardware part of the system is comprised of Arduino Mega 2560 Rev3
controller, W5500 Ethernet Shield expansion card, a complex of sensors,
servodrives, relays, dimmers, an LCD screen, an encoder / potentiometer, etc. A
scheme of the equipment layout was drafted on the detached house plan.
The work of the supply-and-exhaust ventilation system was demonstrated
with the help of a model board on which servodrives and sensors were installed.
The check demonstrated that the equipment can work according to the
predetermined algorithms, and the developed software can be effectively used for
the maintenance of the supply-and-exhaust ventilation in a detached house.
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Khunou, Ramotseng. "Gas sensing properties of Ceo2 nanostructures." University of the Western Cape, 2020. http://hdl.handle.net/11394/7909.
Full textAbstract:
>Magister Scientiae - MSc<br>The industrial safety requirements and environmental pollution have created a high demand to develop gas sensors to monitor combustible and toxic gases. As per specifications of World Health Organization (WHO) and Occupational Safety and Health Administration (OSHA), lengthy exposure to these gases lead to death which can be avoided with early detection. Semiconductor metal oxide (SMO) has been utilized as sensor for several decades. In recent years, there have been extensive investigations of nanoscale semiconductor gas sensor.
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Haensch, Alexander [Verfasser]. "CO2 gas sensors based on rare earth oxycarbonates / Alexander Haensch." Aachen : Shaker, 2016. http://d-nb.info/111825869X/34.
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Graham, Cathy D. "Chemosensitive Neurons of the Locus Coeruleus and the Nucleus Tractus Solitarius: Three Dimensional Morphology and Association with the Vasculature." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1409665728.
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da, Silva Falcao Bruno. "CO2-rock interaction during CO2-enriched brine injection into storage reservoirs using NMR integrated with fiber optic sensors." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2505.
Full textAbstract:
The combustion of fossil fuels has led to a global temperature increase due to the emission of carbon dioxide, which is the major contributor to global warming. The mitigation of CO2 emissions into the atmosphere is therefore critical, where new technologies need to be urgently developed and employed on a large scale. One promising method is to capture anthropogenic CO2 and store it in geological formations, e.g. depleted oil and gas reservoirs and saline aquifers. This process is referred to as carbon capture and storage (CSS).
The storage of CO2 in depleted oil and gas reservoirs that have trapped hydrocarbons for millions of years, requires the evaluation of their storage capacity as well as CO2 leakage risks to ensure long-term safety. Therefore, reservoir conditions need to be monitored, namely pressure and strain changes to avoid compromising the geo-mechanical strength of the reservoir rock, which could reactivate faults and lead to pathways for CO2 leakages. Rock strain is conventionally evaluated by linear variable differential transformers (LVDT) and electrical resistance strain gauges (ESG) that are attached to a rock sample’s surface. However, the geo-mechanical response obtained under laboratory conditions often mismatches with the response of an underground rock formation due to heterogeneity and anisotropy that are not captured by LVDT and ESG. Therefore, Fiber Bragg Grating (FBG) sensing has become a promising alternative due to its various advantages, such as resistance to electromagnetic interference, high-pressure and -temperature, small size, multiplexing capability, amongst others. In this study, FBG sensing technology was applied to measure strain changes in uniaxial compressive strength (UCS) and hydrostatic compressive tests of a standard plexiglass (PMMA) and limestone rock samples. The FBG fiber was wrapped around the samples in a helix with circumferential loops alongside the sample. To allow strain transfer, the fiber was glued onto the sample surface using Loctite Super Glue. The results showed that the FBG sensors were capable of accurately monitoring strain changes during UCS and hydrostatic compressive tests. Conventional methods were employed for comparison. The measured strain changes by FBG showed significantly higher precision and lower noise compared to the results obtained by LVDT and ESG.
Rock permeability, porosity, fluid saturation and flow characteristics are essential information required to design any CCS project, and are commonly measured by core flooding experiments using nuclear magnetic resonance (NMR). However, NMR is not capable of measuring rock deformation caused by fluid migration. Therefore, the evaluation of the rock sample surface deformation during core flooding has been investigated by associating NMR with FBG sensing technology. An optical fiber with 8 FBG sensors was attached to a Savonnières limestone sample and subsequently mounted to a GeoSpec2 (Oxford Instruments) NMR core analyzer. Brine was injected into the sample at 0.1 cc/min, whilst obtaining saturation profiles by the NMR and simultaneously measuring strain changes by the FBG. The results showed the FBG sensors to be capable of tracking the fluid migration through the sample at a high resolution, and to be in excellent agreement with the saturation profiles measured by NMR. As a result, the association of NMR and FBG has been demonstrated as a very promising tool to monitor fluid injection and strain changes during core flooding experiments.
Tests were conducted to monitor interactions between CO2 and the rock samples. The injected CO2 produces a weak carbonic acid in the presence of formation water that can react with calcite within the rock causing ion dissolution and the formation of secondary minerals. This can in turn lead to significant changes in the geo-mechanical strength of the rock, where it is extremely important for CCS projects to ensure safe long-term CO2 storage. Two sandstone rock samples were used to investigate the injection of live brine – CIPS-2 and CIPS-3. CIPS is an artificial sample consisting of quartz with cement composed by calcite. The CIPS-2 sample was used for the static aging process to evaluate the effect of the CO2 far from the injection point. The CIPS-3 sample was used for the dynamic aging to appraise the CO2 effects near the injection point. The aging process ran for approximately 40 hours, which was long enough to demonstrate that the reaction occurred in the bottom of the samples, with CIPS-3 presenting a stronger mineral dissolution. The changes in the samples internal structure were confirmed by CT scan images and NMR measurements. The FBG sensors were able to track strain changes at this specific location of the sample, allowing for quantification of changes in the geo-mechanical strength of the rock sample caused by the reaction of CO2 with calcite.
Overall, FBG sensing technology has been used in this study to accurately measure geo-mechanical rock strain properties at a significantly lower noise level and higher precision than conventional sensors. Further, the association of NMR with FBG sensing technology has been demonstrated in the study. Strain changes were measured at high accuracy during the core flooding process, allowing for tracking of fluid migration within a rock sample. In addition, the strain changes were shown to be related to the rock structure, confirmed by CT scanning images prior to and after the experiment. Possible changes to the rock structure caused by the reaction of dissolved CO2 and the rock were also tracked via FBG technology, allowing for monitoring of the reservoir’s geo-mechanical strength. This is an essential property to ensure the long-term safety of CO2 storage reservoirs.
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Suzuki, Takuya [Verfasser], and Udo [Akademischer Betreuer] Weimar. "Rare-earth based Chemoresistive CO2 Sensors / Takuya Suzuki ; Betreuer: Udo Weimar." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1206933836/34.
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Zhu, Yurong. "A Study of Smart Ventilation System to Balance Indoor Air Quality and Energy Consumption : A case study on Dalarnas Villa." Thesis, Högskolan Dalarna, Mikrodataanalys, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:du-34431.
Full textAbstract:
It is a dilemma problem to achieve both these two goals: a) to maintain a best indoor air quality and b) to use a most efficient energy for a house at the same time. One of the outstanding components involving these goals is a smart ventilation system in the house. Smart ventilation strategies, including demand-controlled ventilation (DCV), have been of great interests and some studies believe that DCV strategies have the potential for energy reductions for all ventilation systems. This research aims to improve smart ventilation system, in aspects of energy consumption, indoor CO2 concentrations and living comfortness, by analyzing long-term sensor data. Based on a case study on an experimental house -- Dalarnas Villa, this research investigates how the current two ventilations modes work in the house and improves its ventilation system by developing customized ventilation schedules. A variety of data analysis methods were used in this research. Clustering analysis is used to identify the CO2 patterns and hence determine the residents living patterns; correlation analysis and regression analysis are used to quantify a model to estimate fan energy consumption; a mathematical model is built to simulation the CO2 decreasing when the house is under 0 occupancy. And finally, two customized schedules are created for a typical workday and holiday, respectively, which show advantages in all aspects of energy consumption, CO2 concentrations and living comfortness, compared with the current ventilation modes.
30
Kang, Donghyeon. "Control of a hexapod robot equipped with proximity, anemoscope, and CO2 sensors." Kyoto University, 2008. http://hdl.handle.net/2433/136632.
Full textAbstract:
Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第13905号<br>農博第1720号<br>新制||農||957(附属図書館)<br>学位論文||H20||N4372(農学部図書室)<br>UT51-2008-C821<br>京都大学大学院農学研究科地域環境科学専攻<br>(主査)教授 梅田 幹雄, 教授 近藤 直, 准教授 中嶋 洋<br>学位規則第4条第1項該当
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Warburton, P. R. G. "An amperometric sensor for carbon dioxide." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233047.
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CATINI, ALEXANDRO. "Sviluppo di sistemi sensoriali per il monitoraggio della qualità dell'aria e per la sicurezza in ambienti esterni e confinati: i casi del CH4, CO2, CO." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/939.
Full textAbstract:
Questo lavoro di ricerca è mirato allo sviluppo di sistemi sensoriali per il monitoraggio della qualità dell'aria. Infatti quando si considera che il rischio di inquinamento può causare grossi problemi di salute anche in un breve periodo di tempo, si evince che il monitoraggio preciso di emissioni inquinanti risulta di fondamentale importanza per la sicurezza e la salute dell'uomo. Gli strumenti convenzionali di monitoraggio della qualità dell'aria non sono molto popolari a causa del fatto che essi risultano essere ingombranti e soprattutto molto costosi. Da qui la necessità di sviluppare un sistema sensoriale economico, compatto, affidabile e soprattutto accurato in grado di poter essere installato in qualunque abitazione ed in qualunque altro luogo ove ci sia bisogno di monitorare una determinata specie gassosa. Inoltre il crescente desiderio di vivere in un ambiente sicuro e confortevole spinge la ricerca verso lo sviluppo di sistemi sensoriali per il monitoraggio di gas tossici, esplosivi ed inquinanti sempre più performanti. In questo contesto vengono presentati due sistemi sensoriali per la rilevazione di gas: un sensore elettro-ottico ed un array capacitivo. Il principio di funzionamento del sensore elettro-ottico si basa sulla legge di Lambert Beer. Il sistema è costituito da un microriscaldatore su membrana (utilizzato come sorgente di radiazione infrarossa), da una cella multipasso (necessaria per aumentare il cammino ottico tra sorgente e rivelatore) e da un array di termopile con filtri ottici centrati nella regione di massimo assorbimento dei gas. Inoltre è stata sviluppata un’elettronica di condizionamento al fine di pilotare in regime sinusoidale il corpo nero ed un’elettronica di rivelazione per acquisire, amplificare, filtrare e visualizzare su un display grafico i segnali in uscita. I risultati sperimentali mostrano un limite di rivelazione di 100 ppm per il CH4, di 20 ppm per il CO ed inferiore a 50 ppm per la CO2.
Il sensore chimico basato su un array di 300x256 micro-capacità è stato realizzato utilizzando un fingerprint sensor commerciale. Sulla superficie del sensore sono state depositate differenti metallo-porfirine; in questo modo i composti volatili presenti nell’ambiente circostante che interagiscono con il materiale sensibile possono essere rivelati dal dispositivo attraverso la misura della variazione della costante dielettrica delle celle che compongono l’array. La variazione della costante dielettrica relativa provoca una variazione della capacità di ogni elemento dell’array. Le misure preliminari hanno evidenziato un limite di rivelazione di 30 ppm per il CO.
In questa tesi verranno descritte e commentate in dettaglio le caratteristiche di entrambi i sistemi, i risultati sperimentali ed i possibili sviluppi futuri.<br>Due to the dramatic growth in industrial development and population, the natural atmospheric environment has become polluted. In fact, when the hazards of environmental pollution that can cause severe injury within a short time period is considered, the precise monitoring of pollutant emissions becomes rather important. Conventional instruments for monitoring the environment are not so popular because they are bulky, time consuming, and expensive. As a consequence, compact, robust, and inexpensive solid-state gas sensors are required as an effective alternative for environmental monitoring.
In this work we present two systems suitable for the detection of volatile compounds: an electro-optical infrared sensor and a capacitive chemical sensor array. The working principle of the electro-optical system is based on the absorption of infrared energy by gas molecules at their characteristic absorption bands; the absorbance is proportional to the concentration according to Lambert-Beer law. The system comprises a micro-heater (used as an infrared source), a multipass cell (required to direct the radiation toward the detector), a thermopile array (detector) with three different filters centered on the absorption peaks of CH4, CO2, CO, and a reference filter. Furthermore, an electronic system has been developed to drive the micro-heater with a sine modulation and to acquire, amplify, filter, and show on a graphic display the output signal.
The results show a limit of detection of 100 ppm for methane, 20 ppm for carbon monoxide and <50 ppm for carbon dioxide.
The capacitive chemical sensor array is based on a commercial fingerprint detector. The device is an array of 300x256 micro-capacitors. Chemical sensors were made by deposition of different metallo-porphryins on the device surface. The volatile compounds present in the close environment and interacting with the sensing materials are detected through the measure of the dielectric constant variation of the cells composing the array. The variation of the relative dielectric constant causes the variation of the capacitance of each element. Tests were performed exposing the sensor to CO with a limit of detection of 30 ppm.
In this thesis are described and commented with details the characteristics of both systems, the experimental results and the future developments.
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Maxwell, Andrew Douglas. "A CO2 measurement system for low-cost applications using chemical transduction." University of Southern Queensland, Faculty of Engineering and Surveying, 2002. http://eprints.usq.edu.au/archive/00001468/.
Full textAbstract:
It is demonstrated that by using a miniature chemical reaction vessel under adaptive mechatronic control, it is possible to design and construct a low-cost carbon dioxide measurement system. With further development such a system would be potentially suitable for low-cost commercial application, in particular as sacrificial, single-mission instrumentation packages in horticultural cargo monitoring. Current instrumentation systems for carbon dioxide (CO2) gas measurement are reviewed and their limitations with respect to low cost commercial applications determined. These utilise technology intended for laboratory measurements. In particular the optical energy absorbance of CO2 in the infra-red electromagnetic spectrum. These systems require large optical paths (typically 10cm) in order to measure small CO2 concentrations. This in turn has a large impact on the physical size of the sensing system. Of the many applications requiring online CO2 sensing packages (such as medical, petroleum, environmental and water treatment)the horticultural industry is the primary focus for this research. CO2 sensing systems are primarily used in horticulture to monitor the produce environment and help extend storage time. For these applications CO2 concentrations are typically low (in the range 0 to 1%) and the paramount need is for low-cost (and possibly disposable) sensing packages. The basis of the measurement technique is the use of bulk (but small volume) aqueous chemical reaction under mechatronic control. Unlike thin film technologies where very thin membranes are passively exposed to the gaseous sample, here a small volume (approximately 2mL) of simple and very cheap liquid chemical indicator (calcium hydroxide solution) is used to produce an opaque precipitate. CO2 concentration is then assessed by low-cost optical attenuation measurements of the developing opacity of the solution. The instrumentation package comprises pumps, flowmeter, reaction cell and infra-red optics for the turbidity measurement, plus reagent and waste vessels, pipelines and electronics. During each measurement cycle, the reaction cell is flushed, with fresh chemical indicator and a sample of gas admitted. The indicator and the sample gas are then vigorously mixed and the change in the indicators optical properties measured at regular intervals. An embedded 8-bit microcontroller performs the necessary analysis to deduce the CO2 concentration (as percentage by volume) for the sample gas by reference to one or more of five ``Time-To-Threshold'' calibration models. These models evaluate the trend in turbidity development as precipitate is formed. First and second prototypes of the measurement system have been constructed and their (low-cost) components and overall performance evaluated, the first a `proof-of-concept' and the second to investigate methodology shortcomings. As a result the design of a third prototype is outlined. The measurement systems have been shown to work adequately well within expected limitations, resulting in a usable low-cost measurement technique. The current prototypes have a useful range of at least 5% to 100% CO2 with a discrimination of typically +-6%. Deficiencies, particularly performance at low concentrations, are identified and potential enhancements for future prototypes proposed.
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Clark, D. "Electrochemical sensors for medical gases." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382605.
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Arshad, Fasiha. "A Study of Smart Ventilation System for Maintaining Healthy Living by Optimal Energy Consumption : A case study on Dalarnas Villa." Thesis, Högskolan Dalarna, Mikrodataanalys, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:du-35967.
Full textAbstract:
Indoor air quality is a measure of clean air with comfort conditions and depiction of lower concentration of air pollutants. It is tedious task to achieve all quality measures at a time with smart energy consumption. This research aims to come up with a solution of how to improve smart ventilation system in order to get clean indoor air with less consumption of electric energy. Many studies showed that scheduled ventilation system has proven to be a good solution to this problem. For this purpose, a long-term sensor data of smart ventilation system Renson healthbox and Luvians data is studied which is operated in Dalarnas villa. This research investigates how this system works in two modes and to improve it by customized scheduling.A regression model is constructed in which the relationship between airflow and CO2 is shown. For this purpose, correlation analysis is used in which the connection of bonds between each data features are analyzed. After the feature selection, as a result from correlation matrix, regression analysis is used to find out whether the selected features are linearly related or not. Regression analysis also used for the intent to quantify a model to estimate the flowrate and CO2. A mathematical model is also build to simulate the flowrate and CO2 with energy consumption.The results showed that, in order to provide better indoor air quality with efficient energy consumption, a necessary modification of the fan schedule should be done in a way that fan must be started little bit earlier to avoid harmful particles reach their upper threshold limits. This can result in reduction of fan’s maximum speed hence consumption of less energy is achieved.
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Sánchez-Cañete, Enrique P., Russell L. Scott, Haren Joost van, and Greg A. Barron-Gafford. "Improving the accuracy of the gradient method for determining soil carbon dioxide efflux." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/623105.
Full textAbstract:
Soil CO2 efflux (F-soil) represents a significant source of ecosystem CO2 emissions that is rarely quantified with high-temporal-resolution data in carbon flux studies. F-soil estimates can be obtained by the low-cost gradient method (GM), but the utility of the method is hindered by uncertainties in the application of published models for the diffusion coefficient. Therefore, to address and resolve these uncertainties, we compared F-soil measured by 2 soil CO2 efflux chambers and F-soil estimated by 16 gas transport models using the GM across 1year. We used 14 published empirical gas diffusion models and 2 in situ models: (1) a gas transfer model called Chamber model obtained using a calibration between the chamber and the gradient method and (2) a diffusion model called SF6 model obtained through an interwell conservative tracer experiment. Most of the published models using the GM underestimated cumulative annual F-soil by 55% to 361%, while the Chamber model closely approximated cumulative F-soil (0.6% error). Surprisingly, the SF6 model combined with the GM underestimated F-soil by 32%. Differences between in situ models could stem from the Chamber model implicitly accounting for production of soil CO2, while the conservative tracer model does not. Therefore, we recommend using the GM only after calibration with chamber measurements to generate reliable long-term ecosystem F-soil measurements. Accurate estimates of F-soil will improve our understanding of soil respiration's contribution to ecosystem fluxes.
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Huo, Wei. "Controlled Fabrication System of Fabry-Perot Optical Fiber Sensors." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/10033.
Full textAbstract:
The use of optical fiber sensors is increasing widely in industry, civil, medicine, defense and research. Among different categories of these sensors is the Extrinsic Fabry-Perot interferometer (EFPI) sensor which is inherently simple and requires only modest amount of interface electronics. These advantages make it suitable for many practical applications. Investigating a cost-effective, reliable and repeatable method for optical fiber sensor fabrication is challenging work. In this thesis, a system for controlled fabrication of Fabry-Perot optical fiber sensors is developed and presented as the first attempt for the long-term goal of automated EFPI sensor fabrication. The sensor fabrication control system presented here implements a real-time control of a carbon dioxide (CO₂) laser as sensor bonding power, an optical fiber white light interferometric subsystem for real-time monitoring and measurement of the air gap separation in the Fabry-Perot sensor probe, and real-time control of a piezoelectric (PZT) motion subsystem for sensor alignment. The design of optoelectronic hardware and computer software is included. A large number of sensors are fabricated using this system and are tested under high temperature and high pressure. This system as a prototype system shows the potential in automated sensor fabrication.<br>Master of Science
38
Jin, Xin. "Regulation of Ca2+ activated Cl- channel ANO1 (TMEM16A) by different Ca2+ sources in sensory neurons." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/9246/.
Full textAbstract:
Proteins of anoctamin (TMEM16) family are the candidate subunits for Ca2+- activated Cl- channels (CaCC). In recent years, studies have shown that anoctamin-1 (TMEM16A or ANO1) plays important physiological roles in processes including epithelial fluid secretion, muscle contraction and olfactory transduction. How the Ca2+ regulates the activity of ANO1 in different tissue is still not clear. In this study, I showed that the excitatory CaCC in nociceptors (small-diameter sensory neurons that are responsible for transmission of painful stimuli) was activated by the release of Ca2+ from the 1, 4, 5-trisphosphate (IP3)-sensitive intracellular stores in response to bradykinin (BK) or proteases (through protease activated receptor 2). Interestingly, while in the majority of nociceptors, CaCC was induced by Ca2+ release from the stores, only in a few neurons CaCC was activated by the Ca2+ influx through the voltage-gated Ca2+ channels (VGCC). Chelating intracellular Ca2+ with the slow Ca2+ buffer EGTA did not affect CaCC activation by protease activated receptor 2 (PAR2), while BAPTA abolished such activation, suggesting a close proximity of the Ca2+ release sites and CaCC. Membrane fractionation demonstrated that in the dorsal root ganglion (DRG), ANO1, bradykinin receptor 2 (B2R) or PAR2, were co-purified with lipid raft marker caveolin-1. Using various biochemical approaches I further demonstrated that ANO1 physically interacted with the IP3 receptor 1 (IP3R1) in DRG. Moreover, IP3R1, ANO1, B2R, and/or PAR2 were all assembled into functional signalling complexes and the plasma membrane components of the complex which contained ANO1 and GPCRs were tethered to the juxtamembrane regions of the endoplasmic reticulum. Disruption of the membrane microdomains by methyl-beta-cyclodextrin (MβCD) or competitive peptides partially restored coupling of CaCC to VGCC but disrupted coupling between B2R or PAR2 signaling and ANO1. Thus, such molecular complexes dichotomize different Ca2+ sources to provide ANO1-mediated excitation in response to specific ambient signals but protect the channels from global changes in intracellular Ca2+ and prevent sensory neurons from overexcitability.
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Wilzewski, Jonas S. [Verfasser], and Bernhard [Akademischer Betreuer] Mayer. "Towards CO2 emission monitoring with passive air- and space-borne sensors / Jonas S. Wilzewski ; Betreuer: Bernhard Mayer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1238017126/34.
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Santos, Camila Paixão [UNESP]. "Fabricação e caracterização de filmes espessos de CeO2 puro para aplicação em sensores de gás." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/144639.
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Previous issue date: 2016-09-03<br>Não recebi financiamento<br>Este trabalho apresenta e discute o uso do óxido de cério na fabricação de filmes espessos por “screen printing” para aplicações em sensores de gás. Nesse estudo o CeO2 puro foi obtido pelo método dos precursores poliméricos utilizando como resina precursora o citrato de céria. O “puff” – espuma resultante da primeira fase do tratamento térmico da resina- foi calcinado a 550, 600, 700 e 750°C. O pó foi caracterizado por termogravimetria (TG) e as propriedades estruturais, morfológicas foram avaliadas por difratometria de raios X (DRX), espectroscopia Raman, área de superfície por isotermas Brunauer, Emmett e Taller (BET) e microscopia eletrônica de varredura (MEV). A resposta sensora foi estudada em uma câmara de teste construída no Laboratório de Catálise e Superfícies do Instituto de Ciência de Tecnologia de Materiais (INTEMA) da Universidade de Mar del Plata. A TG mostrou a formação de óxido de cério a 550°C, temperatura relativamente baixa quando comparada com outros métodos. Mediante DRX todas as amostras mostraram picos correspondentes à fase pura de CeO2 o qual cristaliza em uma estrutura cúbica do tipo fluorita, entretanto, maiores temperaturas de calcinação mostraram aumento da cristalinidade e tamanho do cristalito. No espectro Raman, um forte pico em torno do 461 cm-1 foi detectado, atribuído às vibrações simétricas do Ce-O. A área de superfície BET dos pós foi de 301, 77 m2/g o que evidencia a formação de partículas muito pequenas e altamente reativas. As micrografias obtidas por MEV mostram a presença de diferentes tamanhos na forma de aglomerados. A caracterização da resposta sensora mostrou que o sensor fabricado a partir de pós de CeO2 puro apresenta um bom tempo de resposta, alcançando a melhor performance com temperatura de trabalho de 400 °C, tanto em atmosferas redutoras e oxidantes. A característica principal observada foi que os resultados são dependentes dos ciclos anteriores, a reprodutibilidade do sistema é garantida quando se apaga a “memória” do sistema, expondo-o ao vácuo.<br>This paper presents and discusses the use of cerium oxide in the production of thick films for "screen printing" for applications in gas sensors. In this study the pure CeO2 was obtained by the polymeric precursor method using as a precursor resin citrate ceria. The "puff" - resulting foam from the first stage of thermal treatment of the resin-calcined at 550, 600, 700 and 750 °C. The powder was characterized by thermogravimetry (TG) and structural, morphological were evaluated by X-ray diffraction (XRD), Raman spectroscopy, isothermal Brunauer surface area, Emmett and Taller (BET) and scanning electron microscopy (SEM) . The sensor response was studied in a test chamber built in the Laboratory of Catalysis and Surface Materials Technology Institute of Science (INTEMA), University of Mar del Plata. The thermogravimetry showed the formation of cerium oxide at 550° C, relatively low temperature compared with other methods. Upon XRD all samples showed peaks corresponding to pure CeO2 phase which crystallizes in a cubic fluorite type structure, however, higher calcination temperatures showed increased crystallinity and crystallite size. In the Raman spectrum, a strong peak around 461 cm-1 was detected, assigned to symmetric vibrations of the Ce-O. The BET surface area of the powders was 301, 77 m2 /g which shows the formation of very small and highly reactive particles. The SEM micrographs show the presence of different sizes in the form of agglomerates. The characterization of the sensor response showed that the sensors manufactured from pure CeO2 powder has a good response time, achieving better performance at 400 °C working temperature in both reducing and oxidizing atmospheres. The main feature observed was that the results are dependent on previous cycles, the system reproducibility is guaranteed when it deletes the "memory" of the system, exposing it to vacuum.
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Nunes, Bruno Rios Patriarca. "Maximum lifetime broadcast problem in wireless sensor networks." Escola Politécnica / Instituto de Matemática, 2013. http://repositorio.ufba.br/ri/handle/ri/21338.
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Dissertacao de Mestrado - Bruno Rios Patriarca Nunes.pdf: 1161824 bytes, checksum: ad90a85de8a47398b1ead19074bc473d (MD5)<br>Redes de sensores sem o (RSSF) são compostas por um conjunto de dispositivos, geralmente de baixa capacidade de processamento e autonomia de energia limitada, com o objeto de coletar dados sobre a area onde foi instalada e envia-los ate as unidades de processamento chamadas de estações base. Dentre os recursos de um no sensor, pode-se considerar como um dos mais críticos a carga de bateria, ja que ela de ne em ultimo caso o tempo de vida util do no. Por conta disso, e necessario que os protocolos e aplicações otimizem o uso de energia a m de prolongar o tempo de vida do no sensor e, consequentemente, de toda a RSSF.Este trabalho dedica-se a estudar o problema da maximiza¸c˜ao do tempo de vida da
rede durante uma s´erie de opera¸c˜oes de broadcast. Para o escopo desta pesquisa, o tempo
de vida da rede de sensor ´e definido como o tempo at´e a falha do primeiro n´o por falta
de energia. H´a diversos protocolos na literatura que buscam minimizar o consumo de
energia durante a dissemina¸c˜ao de mensagens na rede, por´em neles n˜ao s˜ao considerados
aspectos como o custo de recep¸c˜ao ou a presen¸ca de links assim´etricos entre os n´os. Neste
trabalho, propomos o algoritmo DLMCA para o problema de maximiza¸c˜ao do tempo de
vida da rede. O algoritmo DLMCA baseia-se na constru¸c˜ao de arborescˆencias de custo
m´ınimo, ´e localizado e considera redes com custos de comunica¸c˜ao assim´etricos, o que ´e
especialmente importante em casos em que a RSSF ´e composta por dispositivos diferentes.
Os experimentos realizados mostraram que o DLMCA ´e mais eficiente que solu¸c˜oes alternativas
propostas na literatura. A heur´ısitca oferecida pelo DLMCA para redes est´aticas
foi levemente adaptada e o problema tamb´em foi analisado para redes m´oveis. Para estas
redes, os experimentos demonstraram que a solu¸c˜ao baseada no DLMCA tamb´em foi
superior em rela¸c˜ao a outras propostas tanto em rela¸c˜ao `a energia total gasta em cada
operação de broadcast quanto em relação ao tempo de vida da rede.
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Hwang, Ji-Young. "Biochemical and biophysical studies on guanylate cyclase activating protein 1, a Ca2+-sensor in Phototransduction." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962777412.
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Talley, Sharon. "A Sensory Tour of Cape Cod: Thoreau's Transcendental Journey to Spiritual Renewal." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc2264/.
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Predominantly darker than his other works, Cape Cod depicts Henry David Thoreau's interpretation of life as a struggle for survival and a search for salvation in a stark New England setting. Representing Thoreau's greatest test of the goodness of God and nature, the book illustrates the centrality of the subject of death to Thoreau's philosophy of life. Contending that Thoreau's journey to the Cape originated from an intensely personal transcendental impulse connected with his brother's death, this study provides the first in-depth examination of Thoreau's use of the five senses in Cape Cod to reveal both the eccentricities inherent in his relationship with nature and his method of resolving his fears of mortality. Some of the sense impressions in Cape Cod--particularly those that center around human death and those that involve tactile sensations--suggest that Thoreau sometimes tried to master his fears by subconsciously altering painful historical facts or by avoiding the type of sensual contact that aggravated the repressed guilt he suffered from his brother's death. Despite his personal idiosyncrasies, however, Thoreau persisted in his search for truth, and the written record of his journey in Cape Cod documents how his dedication to the transcendental process enabled him to surmount his inner turmoil and reconfirm his intuitive faith. In following this process to spiritual renewal, Thoreau begins with subjective impressions of nature and advances to knowledge of objective realities before ultimately reaching symbolic and universal truth. By analyzing nature's lessons as they evolve from Thoreau's use of his senses, this dissertation shows that Cape Cod, rather than invalidating Thoreau's faith, actually expands his transcendental perspective and so rightfully stands beside Walden as one of the fundamental cornerstones of his canon. In addition, the study proffers new support for previous psychoanalytical interpretations of Thoreau and his writings, reveals heretofore unrecognized historical inaccuracies in his account of the shipwreck that frames the book's opening, and provides the first detailed consideration of the linguistic implications of Cape Cod.
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Kim, Man Su. "Regulatory mechanisms of the Ca2+-dependent transcription factor NFAT in sensory neurons." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/832.
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Ca2+-mediated regulation of gene expression plays an important role in neuronal plasticity. NFAT (Nuclear Factor of Activated T-cells) is a Ca2+/calcineurin (CaN)-dependent transcription factor that has been implicated in a number of neuronal functions including axon outgrowth, presynaptic remodeling and neural survival. NFAT is activated by Ca2+/CaN-dependent dephosphorylation, whereas re-phosphorylation by glycogen synthase kinase-3β (GSK3β) and several other protein kinases deactivates NFAT and triggers its export from the nucleus. In addition to electrically-mediated Ca2+ signals, neurotrophins can potently regulate NFAT function in neurons as well. However the mechanisms of NFAT activation by electrical activity and neurotrophins are not completely understood.
In aim 1, I found that electrical stimulation produced a mitochondrial Ca2+ cycling-mediated prolonged [Ca2+]i elevation (plateau), which profoundly affected NFAT activity. The elimination of the [Ca2+]i plateau by blocking mitochondrial Ca2+ uptake or release strongly reduced nuclear import of NFAT. Furthermore, preventing Ca2+ mobilization from mitochondria diminished NFAT-mediated transcription. In aim 2, I found that NGF, a family of neurotrophins, potentiated NFAT-dependent transcription triggered by electrical activity through the TrkA-PI3K-Akt-GSK3β pathway and this effect was mediated primarily by NFATc3. Monitoring NFATc3 movement in DRG neurons in real time showed that NGF slowed the rate of NFATc3 nuclear export, which was mimicked by inhibiting GSK3β, whereas blockade of PI3K prevented this effect. Taken together, I proposed that mitochondrial Ca2+ cycling functions as a novel regulatory mechanism for NFAT activation and NFATc3 serves as an integrator of electrical activity and neurotrophin signaling in the regulation of gene expression in DRG neurons.
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El, Younsi Imane. "Elaboration et caractérisation de nouvelles couches sensibles pour la réalisation de capteurs de CO2." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30344/document.
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La mesure du taux de CO2 est un besoin relativement récent. Les travaux sur l'utilisation de nouveaux matériaux pour la réalisation de capteurs de gaz, efficaces et peu chers, suscitent des intérêts scientifique et technologique croissants. L'objectif de ces travaux de thèse est l'élaboration et la caractérisation de nouvelles couches sensibles obtenues par pulvérisation cathodique radiofréquence pour la réalisation de capteurs de CO2. Les films minces ont été déposés à partir d'une cible céramique de CuO, dans diverses conditions de dépôt, en variant la pression d'argon dans l'enceinte et la puissance RF appliquée. Dans un premier temps, nous avons caractérisé la structure et la microstructure des films bruts et recuits sous air par DRX, MEB, AFM et spectroscopie Raman. Nous avons également étudié les propriétés physiques des films minces ainsi que leur surface accessible par adsorption de gaz krypton (méthode de Brunauer, Emmett et Teller). Le traitement thermique à 450°C n'affecte pas la structure cristalline des couches, en revanche il tend à faire chuter fortement la surface accessible entre les colonnes. Après l'optimisation des paramètres de fonctionnement de la cellule de mesure, nous avons caractérisé les performances des films de CuO pour la détection du CO2. La meilleure réponse (?R/R=51 %) a été obtenue pour une couche élaborée à 2 Pa avec une puissance RF de 30W. De plus, la température optimale de mesure est relativement basse (T= 250°C). Le contrôle de la microstructure et plus particulièrement de la taille des grains s'est avéré être le paramètre principal qui impacte la réponse sous CO2. Les meilleurs résultats ont été obtenus avec des tailles de grains proches d'une vingtaine de nanomètres de diamètre. Une bonne modélisation de la réponse électrique en fonction de la taille des grains a pu être réalisée en prenant en compte un circuit électrique équivalent comportant une zone enrichie en porteur de type trous à la surface des grains et dont l'épaisseur est de l'ordre de la longueur de Debye<br>The measure of the rate of CO2 is a recent need. The works on the use of new materials for the conception of gas sensors based semiconductor oxides, effective and not expensive; arouse a huge interest in our society. The objective of this thesis is the elaboration and the characterization of new sensitive layers obtained by RF sputtering for the realization of the sensors of CO2. Thin films were deposited using two targets: CuFeO2 and CuO, under three conditions by varying argon pressure and RF power. First of all, the structure and the microstructure were studied for the as-deposited samples. Surface investigations carried out by Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), Raman spectroscopy, BET measurements and MEB-FEG images have shown a strong influence of deposition technique parameters on film surface topography and morphology. In a second step, the thin films were annealed in air in order to oxidize the phase. For the composite CuO/CuFe2O4, Glow discharge optical emission spectrometry technique showed a structure in two layers stacked on top of each other for the thinner films. For the cupric films, no changes on both structure and microstructure have been revealed. Our films have then been evaluated for CO2 detection. The sensitive layers with different thicknesses were sensitive to 5000 ppm of CO2. The deposition parameters are optimized to obtain microstructure features which can enhance the sensitivity of the thin films as gas sensors. Best response was obtained for a cupric sample deposited in P2 30W conditions and was close to 50% at T = 250°C. We have demonstrates that cupric oxide alone can detect the CO2 gas and that the growth conditions determine the film surface characteristics. The gas sensing characteristics of these films are strongly influenced by both surface morphology and microstructure
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Menghini, Massimiliano. "Sviluppo e sperimentazione di sensori per il monitoraggio della qualità dell'aria." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10249/.
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Individuare e conoscere la natura degli inquinanti atmosferici e disporre dei dati delle emissioni sono azioni fondamentali per formulare politiche ambientali incentrate sul miglioramento della qualità dell'aria e monitorarne l'efficacia. Sorge l'esigenza di un controllo costante della qualità dell'aria, processo che avviene utilizzando delle centraline di monitoraggio fisse sparse nelle vie delle maggiori città o nei pressi dei principali insediamenti industriali.
Lo scopo di questo progetto è quello di realizzare una stazione di monitoraggio mobile al fine di aumentare la superficie di controllo, realizzando un oggetto dinamico capace di acquisire dati sull'inquinamento. Questo è stato fatto applicando ad un drone un sistema di sensori capaci di rilevare le variazioni dei livelli di concentrazione degli agenti inquinanti. Ciò permette di eliminare le stazioni di monitoraggio fisse, le quali rappresentano una spesa ingente. Inoltre, attraverso l'utilizzo di un drone, è possibile monitorare siti più vasti, permettendo un monitoraggio costante e ripetuto nel tempo.
La prima parte dell'elaborato analizza il sistema Embedded utilizzato per l'acquisizione dei dati, concentrando l'attenzione prevalentemente sui moduli utilizzati.
La seconda descrive quali sono i primi passi per cominciare ad utilizzare i sensori posti sulla Gases Board 2.0 e risponde ai dubbi più comuni su quali parametri di configurazione adottare per un avere una risposta adeguata, quale processo di calibrazione seguire o come trasformare i dati acquisiti, espressi in tensioni, in valori di concentrazione di gas.
La terza parte illustra i test effettuati per verificare il corretto funzionamento del sistema completo, con l’esposizione delle problematiche individuate, e una presentazione delle alternative più valide per superarle.
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Sutton, Kathy Gayle. "Action of polyamine and polypeptide toxins CA2+channel and CA2+-dependent chloride currents from rat central and sensory neurones in culture." Thesis, St George's, University of London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265354.
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Králová, Petra. "Přídavek oxidu uhličitého do mléka pro výrobu sýrů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216613.
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This work deals with the addition of carbon dioxide to milk for cheese production. The first aim was to elaborate a literary search focused on chemical composition of milk and its changes after addition of carbon dioxide and to describe production processes, with or without addition of carbon dioxide. The opening part was in particular focused on production of cheese with carbon dioxide and what all this gas causes during production. Carbon dioxide significantly decreases pH, thereby preventing from multiplication of undesirable microorganisms, it is also very important for shortening of production time, because it shortens the coagulation time. The main aim of experimental part was to determine the optimum addition of carbon dioxide to milk for production of Balkan cheese and using several analytical methods to compare cheese produced with and without addition of carbon dioxide. The sensory methods suitable for following of sensory differences of produced cheeses were also chosen and applied. By request of Dairy in Polná Ltd., the operation economy was calculated, which revealed that production with carbon dioxide is very useful and can reduce production costs of Balkan cheese, which would certainly be positive. The advantages and disadvantages of cheese production with carbon dioxide for consumers as well as for producer are evaluated as conclusion of this work.
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DE, NADAI ANDREA. "Sintesi e caratterizzazione di sensori chimici fluorescenti per l'imaging di Ca2+ in sistemi viventi." Doctoral thesis, Università degli studi di Padova, 2022. http://hdl.handle.net/11577/3459750.
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I segnali di calcio (Ca2+) regolano molti processi biologici. L’alta versatilità del Ca2+ come messaggero intracellulare si basa sulla capacità che ha la cellula di controllare accuratamente l’ampiezza e la durata delle fluttuazioni della sua concentrazione. Molti sforzi sono stati profusi per lo sviluppo di strumenti per la misurazione della concentrazione intracellulare di Ca2+ ([Ca2+]).
Recentemente, l’attenzione dei ricercatori si è focalizzata sulla comprensione delle dinamiche del Ca2+ all’interno dei singoli compartimenti subcellulari, e di conseguenza si è reso necessario lo sviluppo di sensori organello-specifici. Infatti, gli organelli, internalizzando e rilasciando Ca2+, rivestono un ruolo chiave nella modulazione della [Ca2+] citosolica.
Diversi indicatori per il Ca2+ geneticamente codificati (GECIs) per l’espressione in specifici organelli sono stati sviluppati. Questa tipologia di indicatori, tuttavia, soffre di diversi svantaggi: ad esempio risultano necessarie complesse procedure di trasfezione per il loro utilizzo, rendendoli non applicabili a tutte le tipologie cellulari.
Gli indicatori chimici per il Ca2+ (CCIs) rappresentano una valida alternativa ai GECIs. I CCIs sono tipicamente basati su un fluoroforo organico covalentemente legato al dominio chelante del Ca2+ del BAPTA. Il gruppo acetossimetil (AM) estere viene usato per proteggere bio-reversibilmente le funzionalità carbossiliche poiché la forma acida del BAPTA non è in grado di permeare le membrane cellulari.
L’obiettivo di questo progetto è lo sviluppo e la caratterizzazione di nuovi CCIs capaci di monitorare in vivo in tempo reale la [Ca2+] in specifici compartimenti cellulari. Tale scopo può essere conseguito con lo sviluppo di nuovi sensori basati su indicatori raziometrici fluorescenti con un’affinità per il Ca2+ adeguatamente modulata, funzionalizzati con domini molecolari che ne conferiscano una specifica localizzazione subcellulare.
Tre nuovi sensori mitocondriotropici per il Ca2+ sono stati sviluppati sfruttando l’abilità di targeting dei cationi lipofilici di trifenilfosfonio. Tali sensori hanno dimostrato la loro capacità nel permeare la membrana plasmatica e accumulare selettivamente nei mitocondri e di rispondere in modo coerente alle variazioni di [Ca2+] nella matrice mitocondriale, anche in sistemi cellulari dove l’utilizzo dei GECIs è problematico.
Per veicolare i CCIs nel lume dell’ER è stata sfruttata la coniugazione con cicloesil sulfonil urea o toluen sulfonammide. Nonostante l’approccio di targeting ha dimostrato di veicolare i due precursori sintetizzati nell’ER, la forma AM estere non è stata in grado di attraversare la membrana plasmatica. Un terzo sensore è stato quindi sintetizzato per superare i problemi di diffusione.
Sono stati inoltre sviluppati tre CCIs fluorescenti e raziometrici, aventi diverse affinità per il Ca2+ e capaci di emettere fluorescenza nella porzione rossa dello spettro elettromagnetico per evitare l’eccitazione dei sensori con radiazione UV. Questi nuovi indicatori hanno inoltre mostrato un interessante accumulo selettivo nei lisosomi, dove il pH acido ostacola l’accurata determinazione della [Ca2+].
Infine, un approccio basato sulla coniugazione del peptide NLS (Nuclear Localization Sequence) è stato sperimentato come proof-of-principle di CCIs veicolati al nucleo di cellule viventi. Questi sensori non hanno tuttavia dimostrato un’adeguata permeabilità alla membrana plasmatica.
La disponibilità di strumenti affidabili per misurare direttamente la [Ca2+] negli organelli cellulari è fondamentale per una comprensione completa dei meccanismi biologici. Oltre a fornire nuovi strumenti per questo importante obiettivo, questo progetto di dottorato ha posto le basi per lo sviluppo di nuove sonde per la misurazione, in principio, di qualsiasi analita in precisi compartimenti subcellulari.<br>Calcium (Ca2+) signaling triggers essential biological processes. The high versatility of Ca2+ as an intracellular messenger relies on the possibility of finely tuning both the amplitude and time course of Ca2+ waves, which contribute to the specification of downstream effects. Starting from the ‘80s, many efforts have been devoted to the generation of tools to measure intracellular Ca2+ concentration ([Ca2+]).
In recent years, the attention of researchers moved to Ca2+ dynamics inside subcellular compartments, and the need for organelle-targeted indicators has become critical. Indeed, by taking up and releasing Ca2+, intracellular organelles are fundamental players in shaping cytosolic Ca2+ signals. Several organelle-targeted genetically-encoded Ca2+ indicators (GECIs) have been developed so far. However, they suffer from different drawbacks, e.g., the need of transfection procedures to be delivered and the Ca2+-affinity not readily controllable.
Chemical Ca2+ indicators (CCIs) represent a valid alternative to GECIs. They are typically based on an organic fluorophore covalently linked to the Ca2+ chelating domain 1,2-bis(o-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid (BAPTA), with high selectivity for Ca2+ over Mg2+. Acetoxymethyl (AM) esters groups are used to bio-reversibly protect the carboxylic moieties since the free acid form of BAPTA is unable to cross cell membranes. Despite the invaluable impact of CCIs, their organelle-targeting has so far been poorly exploited.
The project goal was to develop new CCIs to monitor in vivo real-time [Ca2+] in specific subcellular compartments. To this end, fluorescent ratiometric dyes with suitably tuned Ca2+-affinity have been combined with molecular features that confer specific subcellular localization. Three primary components constitute the resulting probes: i) a BAPTA-based fluorescent CCI; ii) a specific organelle-targeting moiety; iii) a spacer that covalently joins the two.
Three new mitochondriotropic Ca2+ probes have been developed by exploiting the targeting ability of triphenylphosphonium lipophilic cations. They all demonstrated capabilities to permeate plasma membrane (PM), to selectively accumulate within mitochondria, and to respond consistently to [Ca2+] variations in the mitochondrial matrix, also in cell systems where the delivery of GECIs is troublesome. This represents a major breakthrough in the field of Ca2+ imaging techniques, as the synthesized probes represent the first mitochondria-targeted ratiometric CCIs ever developed.
To deliver CCIs to the ER lumen, conjugation with cyclohexyl sulfonylurea or toluene sulfonamide has been exploited. Despite the targeting approach proved successful to target the two synthesized precursors to the ER, their AM-protected form was unable to cross the PM. A 3rd probe was therefore synthesized to overcome the diffusion problem.
Furthermore, three new red-shifted ratiometric fluorescent CCIs with different Ca2+-affinities have been developed to avoid toxicity due to UV excitation. Interestingly, these dyes showed selective accumulation in lysosomes, where acidic lumenal pH values hamper the accurate determination of [Ca2+] with CCIs, due to protonation of their carboxyl functionalities that influence their Ca2+-affinities.
Finally, a NLS (Nuclear Localization Sequence) peptide-based conjugation approach has been explored as proof-of-principle for Ca2+-sensors delivery inside the nucleus of living cells. Unfortunately, they do not demonstrate adequate PM permeability.
The availability of reliable tools to directly measure [Ca2+] in intracellular organelles is critically important for a comprehensive understanding of biological mechanisms. In addition, this doctoral project has laid the groundwork for the development of new probes for the measurement, in principle, of any analyte in precise subcellular compartments.
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Photinon, Kanokorn. "DEVELOPMENT OF DIMETHYL ETHER (DME) AND CARBON DIOXIDE SENSORS USING PLATINUM NANOPARTICLES AND THICK FILM TECHNOLOGY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=case1164899809.
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