Littérature scientifique sur le sujet « Sensori di gas »
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Articles de revues sur le sujet "Sensori di gas"
1
Hidayat, Nurul, Samsul Hidayat, Nugroho Adi Pramono et Ulfa Nadirah. « Sistem Deteksi Kebocoran Gas Sederhana Berbasis Arduino Uno ». Rekayasa 13, no 2 (1 août 2020) : 181–86. http://dx.doi.org/10.21107/rekayasa.v13i2.6737.
Texte intégralRésumé :
Penggunaan gas di berbagai sendi kehidupan manusia sekarang ini tidak dapat terhindarkan, mulai dari kebutuhan skala rumah tangga hingga industri. Dalam upaya meningkatkan pencegahan terjadinya kecelakaan kerja akibat kebocoran gas, kontrol terhadap kebocoran gas merupakan sebuah tindakan yang vital. Oleh karena itu, makalah ini membahas respon sensor gas MQ2, MQ3, dan MQ5 terhadap gas dan asap. Ketiga sensor gas tersebut dijalankan oleh mikrokontroler ATMega328 dengan modul Arduino Uno. Sebagai aktuator, buzzer digunakan sebagai pengirim sinyal audio dan LED sebagai basis informasi visual terkait pengingat adanya gas berlebih yang terdeteksi oleh MQ2, MQ3, dan MQ5. Secara mekanisme fisis, ketika sensor gas mendeteksi adanya gas berlebih, maka sinyal suara dari buzzer akan aktif sedemikian rupa sehingga dapat digunakan sebagai indikasi dini terhadap keberadaan atau kebocoran gas. Secara umum, sensor gas MQ2, MQ3, dan MQ5 memiliki respon yang sedikit berbeda pada jenis asap dan gas yang berbeda. Pada gilirannya nanti, hasil dari penelitian ini dirancang sebagai informasi penting dalam pemilihan jenis sensor gas sesuai kebutuhan. Simple Gas Leakage Detection System Based on Arduino UnoAbstractThe use of gas in various aspects of human life nowadays is inevitable, ranging from the needs of household scales to industries. As an effort to increase the prevention of occupational accidents due to gas leakage, control of gas leakage becomes a vital action. Therefore, this paper discusses the response of MQ2, MQ3, and MQ5 gas sensors to gases and smokes. The ATMega328 microcontroller ran the three gas sensors with the Arduino Uno module. As an actuator, buzzers were used as audio signal senders and LEDs as a basis for visual information related to reminders of excess gas detected by MQ2, MQ3, and MQ5. The physical mechanism, when the gas sensor detects the presence of excess gas, then the sound signal from the buzzer could be activated in such a way that it can be used as an early indication of the presence of leakage of gas. Generally, MQ2, MQ3, and MQ5 gas sensors performed slightly differently in responding to the presence of gases and smokes. In turn, the results of this study are designed as relevant information in selecting the type of gas sensor as needed.Keywords: Gas sensor, Microcontroller, MQ2, MQ3, MQ5, Simple instrumentation.
2
Indra Ava Dianta, Moh Muthohir, Ilham Ramasyahdani et Fatkhul Amin. « Perancangan Alat Pendeteksi Asap dan Suhu Ruangan Berbasis Internet Of Think di PT. APAC Inti Corpora ». Elkom : Jurnal Elektronika dan Komputer 15, no 2 (5 décembre 2022) : 450–55. http://dx.doi.org/10.51903/elkom.v15i2.859.
Texte intégralRésumé :
In this final project the author discusses the problem entitled "Design of Smoke Detector and Room Temperature of SAP ERP Server at PT Apac Inti Corpora". This design aims to support the improvement of the security system in the server room with smoke and temperature detectors and microcontroller-based automatic countermeasures. Against the background of problems with sensors and countermeasures systems in the server room and lack of insight into sensor installation. This tool uses a gas sensor MQ-2 as a smoke detector, a DHT-11 sensor as a temperature detector, Arduino as a microcontroller that controls I/O, buzzer and LED as an alarm, a fan as a temperature controller, and an LCD to display conditions in the room. The output of the MQ-2 and DHT-11 sensors will be processed in a programmed microcontroller so that it can display conditions on the LCD. This tool will turn on the alarm and fan if smoke and high temperature are detected at the specified conditions.
3
Magna, Gabriele, Manuela Stefanelli, Roberto Paolesse et Corrado Di Natale. « The Chemical Sensitivity of Hybrid Porphyrin Materials ». ECS Meeting Abstracts MA2022-01, no 14 (7 juillet 2022) : 939. http://dx.doi.org/10.1149/ma2022-0114939mtgabs.
Texte intégralRésumé :
Porphyrins and corroles have been used in the last two decades to prepare sensor arrays for a variety of applications [1]. The wide chemical interactivity of these porphyrinoids sustains these applications making possible the measurement of complex patterns of volatile compounds. The interplay between the metal ion, the aromatic ring and the peripheral compounds establishes unique selectivity patterns which are fundamental elements for sensor array design and development. Films of porphyrins and corroles can be adequately applied to inorganic surfaces making possible the preparation of different kinds of chemical sensors. Among them mass transducers, such as Quartz Microbalances (QMBs), have been found particularly suitable for several applications. QMBs do not select the different interaction mechanisms, thus this transducer offer the unique chance to investigate the whole bouquet of interactions established between the volatile compounds and the sensitive layers. Porphyrins and corroles coated QMB sensor arrays have been successfully used in several application in particular to investigate in humans the relationships between volatilome and pathologies. Results include the diagnosis of lung cancer from breath [2], kidney cancer from urines [3], and COVID-19 from blood serum [4]. In the last years, we have been interested in replicating the behavior of QMB sensor arrays with other transduction principle which enables a more simple sensor system design and even the integration of sensors in wearable supports. To this regard the simplest sensor is that based on electric impedance variation. For this scope porphyrins have been grafted onto the surface of nanostructures that can provide a change of impedance as a result of the chemical interaction between porphyrinoids and volatile compounds. For instance, layers of porphyrinoids coated ZnO nanoparticles shown sensitivity towards a large spectra of compounds [5]. Exploiting the optical properties of porphyrins, the sensitivity of this sensors can be triggered by light. As a result, these devices show a negative sensitivity to electron donor compounds (e.g. amines) and a positive sensitivity respect to other compounds. This property can be fruitfully exploited in sensor arrays configuration to classify complex samples such as foods and furthermore to detect spoilage processes. Another example is provided by porphyrnoids coated silica nanoparticles. In this case, the dielectric properties of silica are exploited to develop capacitive sensors whose capacitance is modulated by the absorption of volatile compounds. These sensors retains the chemical sensitivity properties of porphyrins allowing for instance to reproduce the results of the QMB sensors in the identification of COVID-19 blood serum sample. References [1] R. Paolesse, S. Nardis, D. Monti, M. Stefanelli, C. Di Natale, Porphyrinoids for Chemical Sensor Applications, Chem. Rev. 117 (2017) 2517–2583. [2] R. Gasparri, M. Santonico, C. Valentini, G. Sedda, A. Borri, F. Petrella, P. Maisonneuve, G. Pennazza, A. D’Amico, C. Di Natale, R. Paolesse, L. Spaggiari, Volatile signature for the early diagnosis of lung cancer, J. Breath Res. 10 (2016). [3] M. Murdocca, F. Torino, S. Pucci, M. Costantini, R. Capuano, C. Greggi, C. Polidoro, G. Somma, V. Pasqualetti, Y.K. Mougang, C. Di Natale, F.C. Sangiuolo, Urine lox-1 and volatilome as promising tools towards the early detection of renal cancer, Cancers. 13 (2021). [4] Y.K. Mougang, L. Di Zazzo, M. Minieri, R. Capuano, A. Catini, J.M. Legramante, R. Paolesse, S. Bernardini, C. Di Natale, Sensor array and gas chromatographic detection of the blood serum volatolomic signature of COVID-19, IScience. 24 (2021) 102851. [5] G. Magna, M. Muduganti, M. Stefanelli, Y. Sivalingam, F. Zurlo, E. Di Bartolomeo, A. Catini, E. Martinelli, R. Paolesse, C. Di Natale, Light-Activated Porphyrinoid-Capped Nanoparticles for Gas Sensing, ACS Appl. Nano Mater. 4 (2021) 414–424.
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Helmi, Fauzan. « Deteksi Kadar Asap Rokok di Dalam Ruangan Menerapkan Metode Fuzzy Logic Mamdani ». BEES : Bulletin of Electrical and Electronics Engineering 2, no 2 (30 novembre 2021) : 53–62. http://dx.doi.org/10.47065/bees.v2i2.893.
Texte intégralRésumé :
The number of sufferers of respiratory disorders, both young and adult caused by cigarette smoke, has increased every year, from 192 countries it is stated that around 40% of children in the world are exposed to cigarette smoke and more than 30% of adults become passive smokers. Cigarette smoke using an Arduino equipped with a gas sensor makes it easy for early detection when someone wants to smoke in the room, the room should be clean of cigarette smoke and equipped with a temperature sensor if too much smoke can make the temperature in the room it changes. The design of the smoke level detector in cigarettes with smoke sensors and temperature sensors uses the mandani fuzzy logic algorithm, equipped with red and white led indicators, a buzzer to provide information in the form of sound, an LCD display that functions to display smoke and temperature information that can be obtained in the room. , as well as a fan as an output to remove cigarette smoke and cool the room temperature
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Pakdee, Udomdej, Patipak Phunudom, Surawit Nantakarat, Ananya Thaibunnak, Prapaporn Roipromma, Suvanna Rungruang, Piewpan Prajansri et Gun Chaloeipote. « Room Temperature Gas Sensor Based on Helical Carbon Coils ». Key Engineering Materials 798 (avril 2019) : 105–10. http://dx.doi.org/10.4028/www.scientific.net/kem.798.105.
Texte intégralRésumé :
Growth of helical carbon coils can be achieved by sputtered Inconel® 600 films on silicon (Si) substrates followed by thermal chemical vapor deposition (CVD) using acetylene as a carbon source along with the injection of sulfur hexafluoride (SF6). The coils were used to prepare electronic ink for fabrication of flexible room temperature gas sensors. The ink as a sensing film was deposited onto silver-screen printed plastic substrates using a droplet coating technique. Before dripping the sensing film, the coils were purified using oxidation and acid treatments. The purified coils were then dispersed in different solvents such as deionized water (DI water), ethanol and dimethyl sulfoxide (DMSO) for comparisons. The performance of sensors was investigated for its response to ammonia (NH3) and volatile organic compounds (VOCs) including ethanol, methanol, and dimethylformamide (DMF) in concentration of 1000 ppm at room temperature. Because the baseline resistance of sensor falls within the working range (i.e. kΩ), the coils dispersed in DI water are performed to show the highest selectivity and sensitivity to NH3. The sensing mechanism of helically coiled carbon gas sensors has been also discussed based on the reducing reaction process between NH3 and chemisorbed oxygen on the surface of purified carbon coils.
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Akbar, Said Ali. « Sensor Gas Amonia Berbasis Polimer Konduktif Polianilina : Sebuah Review ». QUIMICA : Jurnal Kimia Sains dan Terapan 3, no 2 (2 février 2022) : 1–8. http://dx.doi.org/10.33059/jq.v3i2.4678.
Texte intégralRésumé :
Artikel review ini memberikan informasi tentang aplikasi polianilina (PANI) dan kompositnya sebagai sensor gas berbahaya khususnya amonia (NH3). Kajian yang dibahas pada artikel ini meliputi sifat gas NH3, material komposit, kinerja sensor, serta limit deteksi. Tinjauan sensor gas amonia berbasis polimer konduktif polianilina secara menyeluruh diambil dari referensi sepuluh tahun terakhir. Sebagai contoh, komposit polianilina dengan turunan karbon seperti reduced Graphene Oxide (rGO) dan Carbon Nanotube menunjukkan limit deteksi hingga 46 ppb dengan waktu pemulihan hanya 75 detik. Selain itu, komposit PANI dengan logam seperti Ag, Sr dan sebagainya, menunjukkan limit deteksi yang lebih besar yaitu 1 ppm, namun terdapat keunggulan dimana waktu pemulihan hanya 4 deti. Oleh sebab itu, polimer konduktif polianilina menjadi material yang sangat menjanjikan untuk mendeteksi keberadaan gas NH3. Terakhir, mekanisme penginderaan gas amonia terhadap material PANI juga dibahas pada tulisan ini.
Referensi:
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Stevanus Susilo, Willy, Chyquitha Danuputri, Lukman Hakim et Angelina Pramana Thenata. « RANCANG BANGUN ALAT DETEKSI GAS BERACUN DENGAN ALGORITMA SIMPLE ADDITIVE WEIGHTING ». ZONAsi : Jurnal Sistem Informasi 5, no 1 (23 janvier 2023) : 1–15. http://dx.doi.org/10.31849/zn.v5i1.12706.
Texte intégralRésumé :
Dengan pesatnya perkembangan teknologi, membuat umat manusia menghasilkan semakin banyak emisi gas polutan. Kualitas udara terutama di perkotaan dan permukiman penduduk yang semakin memburuk juga berdampak serius bagi kesehatan paru-paru yang dapat menyebabkan penyakit pernapasan fatal hingga meninggal. Penelitian ini berfokus membangun sistem untuk mendeteksi dan memberi notifikasi berupa peringatan jika udara di sekitar sudah diatas ambang batas aman dan berbahaya berdasarkan 2 jenis gas yaitu karbon monoksida dan ozon dengan implementasi algoritma Simple Additive Weighting. Tak hanya itu, alat ini dirancang dengan fleksibilitas dan skalabilitas yang tinggi agar mudah dikembangkan lebih jauh. Hasil perancangan dan pengembangan dari alat dalam penelitian ini menunjukkan alat dapat bekerja dengan baik dari sisi perangkat keras maupun perangkat lunak dan algoritma yang diterapkan. Namun, untuk mendapatkan pembacaan sensor gas yang akurat, diperlukan proses kalibrasi dengan alat khusus yang hanya ada di laboratorium BSN (Badan Standar Nasional) dan BRIN (Badan Riset dan Inovasi Nasional) di Puspitek. Akhirnya, peneliti memutuskan untuk melakukan penyesuaian nilai pembacaan sensor dengan sensor di stasiun kualitas udara milik KLHK (Kementerian Lingkungan Hidup dan Kehutanan). Hasilnya, sensor gas karbon monoksida memiliki selisih sebesar ± 8,65% jika dibandingkan dengan nilai dari sensor milik KLHK, sedangkan pada sensor gas ozon memiliki selisih sebesar ± 14,61%.
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Ashari, Imam Ahmad, Retno Agus Setiawan et Khoirun Nisa. « Sistem Informasi Deteksi Dini Gas Amonia di Lingkungan Peternakan menggunakan Perangkat Wireless Sensor Network ». Jurnal Ilmu Komputer dan Teknologi 1, no 2 (28 novembre 2020) : 7–10. http://dx.doi.org/10.35960/ikomti.v1i2.573.
Texte intégralRésumé :
Amonia merupakan gas berbahaya yang di hasilkan oleh kotoran unggas di lingkungan peternaan. Ketika mencapi kadar konsentrasi tertentu gas ammonia dapat menyebabkan kematian bagi unggas bahkan untuk peternaknya sendiri. Untuk mengatasi hal tersebut perlu adanya tindakan untuk mengetahui lebih dini kadar konsentrasi gas ammonia yang ada di lingkungan peternakan. Wireless Sensor Network (WSN) merupakan solusi dari masalah itu, dengan perangkat WSN kadar konsentrasi gas ammonia di lingkungan peternakan dapat di monitoring secara realtime. Untuk menampilkan data yang di ambil dari perangkat WSN pada penelitian ini interface menggunkan visualisasi grafik berbasis web. Adapun perancangan wireless sensor network berjalan dengan baik. Data dapat di ambil secara realtime dan di tampilkan dalam system informasi berbasis web dengan visualisasi berbentuk grafik.
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Sokibi, Petrus, et Riza Abdi Nugraha. « PERANCANGAN PROTOTYPE SISTEM PERINGATAN INDIKASI KEBAKARAN DI DAPUR RUMAH TANGGA BERBASIS ARDUINO UNO ». Jurnal Digit 10, no 1 (27 mai 2020) : 11. http://dx.doi.org/10.51920/jd.v10i1.152.
Texte intégralRésumé :
Menggunakan sistem untuk mendeteksi kebakaran adalah suatu pilihan yang berguna untuk memberikan keamanan ketika terjadi bencana kebakaran. Kemajuan teknologi di bidang elektronika berkembang sangat pesat dalam pembuatan alat-alat yang canggih, yaitu alat yang dapat memberikan banyak manfaat dan mempermudah pekerjaan manusia. Munculnya masalah seperti ketika terjadi kebocoran gas LPG yang dapat menjadi pemicu kebakaran, atau ketika munculnya kobaran api yang bisa menyebabkan kebakaran yang lebih besar. Dalam penulisan ini dijelaskan perancangan sistem peringatan indikasi kebakaran di dapur rumah tangga berbasis Arduino Uno yang berfungsi sebagai pemberi peringatan ketika terdeteksi kebocoran gas LPG atau kobaran api. Berdasarkan permasalahan tersebut kemudian muncul gagasan untuk membuat sistem yang dapat memberikan alarm pemberitahuan. Sistem ini terdiri dari Arduino Uno sebagai pengendali utama dari sistem, Sensor Gas MQ2 sebagai pendeteksi kebocoran gas LPG, Sensor Api sebagai pendeteksi nyala api, Buzzer untuk mengeluarkan bunyi peringatan ketika terdeteksi kebocoran LPG atau kobaran api, dan Modul SIM800L yang berguna untuk mengirimkan pemberitahuan melalui SMS ke nomor yang didaftarkan sebelumnya. Untuk pemrograman Arduino menggunakan aplikasi Arduino IDE. Sistem ini nantinya ketika sensor gas atau sensor api mendeteksi kebocoran gas LPG atau kobaran api, data dari sensor tersebut diproses oleh Arduino Uno, kemudian Arduino Uno menyalakan Buzzer dan mengirimkan pemberitahuan melalui SMS ke nomor penerima yang dituju. Hasil dari penelitian ini adalah sistem peringatan indikasi kebakaran di dapur rumah tangga berbasi Arduino Uno.
Kata kunci : Arduino , Sensor Gas, Sensor Api, Buzzer, Modul SIM800L
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Rahman, Budi, Frengki Pernando et Noviar Indriawan. « Sistem Monitoring Kebocoran Gas Dan Api Menggunakan Sensor MQ-2 Dan Flame Sensor Berbasis Android ». Journal Sensi 8, no 2 (26 août 2022) : 209–22. http://dx.doi.org/10.33050/sensi.v8i2.2429.
Texte intégralRésumé :
Berkembangnya ilmu pengetahuan teknologi informasi yang pesat saat ini telah memberikanbanyak manfaat pada masyarakat umum. Dengan adanya teknologi informasi akan mempermudahmanusia dalam melakukan segala hal. Perkembangan yang pesat pada teknologi hardware pun terjadipada perkembangan mikrokontroler Nodemcu ESP8266, suatu alat yang mampu mengkomunikasikanantara bahasa pemrograman dengan modul sensor MQ-2, Flame sensor, Buzzer, Water Pump danKipas DC sehingga dapat membantu memberikan informasi yang dibutuhkan. Denganberkembangannya teknologi software maupun hardware tersebut dapat dimanfaatkan untukmemberikan informasi berupa pemantauan dalam pencegahan bencana, khususnya bencanakebakaran. Oleh karena itu, dengan alat tersebut dibuat sebuah sistem monitoring kebocoran gas danapi yang dihubungkan melalui aplikasi Android, dan pada aplikasi tersebut mempunyai fitur untukmemonitoring kondisi sensor gas MQ-2 dan Flame sensor untuk memastikan kondisi di dalam kantortersebut aman. Dari hasil pengujian, bahwa implementasi Sistem Monitoring Kebocoran Gas dan Apiini dapat berjalan sesuai fungsi. Percobaan dilakukan masing-masing 5 kali pada sensor MQ-2 danFlame Sensor. Pada saat dilakukan pengujian pada sensor MQ-2 di percobaan ke 5 dengan jarakobjek asap atau gas dengan radius 30cm data pada sensor menunjukan angka 424, oleh sebab itudinyatakan aman, lalu saat pengujian Flame sensor di percobaan ke 5 radius objek 30cm dan datapada sensor adalah 1 ini menunjukan kondisi aman.
Thèses sur le sujet "Sensori di gas"
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LONGATO, ALESSANDRO. « Materiali nanostrutturati per sensori di gas ». Doctoral thesis, Università degli studi di Padova, 2022. https://hdl.handle.net/11577/3460976.
Texte intégralRésumé :
Il mio lavoro di ricerca durante il dottorato è stato dedicato allo sviluppo di sensori ottici di gas per due importanti costituenti del gas naturale: odorizzanti e idrogeno.
Gli odorizzanti vengono aggiunti al gas naturale perché quest’ultimo è naturalmente incolore inodore. Pertanto, prima di essere distribuito, vengono aggiunte piccole quantità di tioli per facilitare il rilevamento delle perdite. I due odorizzanti più utilizzati nelle condutture italiane sono il TBM e il THT. È fondamentale misurare questi odorizzanti: una concentrazione troppo bassa non permette di rilevare se c'è una perdita, una concentrazione troppo alta potrebbe allarmare invano. Poiché sia THT che TBM hanno un caratteristico spettro di assorbimento UV, durante il dottorato è stato fabbricato un prototipo chiamato MUDO (Mid-UV Detector for Odorants) che si basa dalla spettrometria UV. Il prototipo è costituito da una lampada al deuterio come sorgente di luce UV, due fibre ottiche, due collimatori, una cella a flusso di gas e uno spettrometro UV. Inoltre, sono stati scritti due programmi in Python per far funzionare l'hardware, raccogliere gli spettri e calcolare le concentrazioni. Con MUDO sono stati effettuati due test in campo, uno a Vicenza, dove la rete del gas è odorizzata con THT, e uno a Milano, dove la rete del gas è odorizzata con TBM. Questi test sono stati eseguiti in parallelo ad un GC per confrontare le misurazioni. I risultati hanno riconosciuto MUDO come un metodo valido per misurare la concentrazione di odorizzante nel gas naturale, in quanto la differenza tra i valori misurati da MUDO e GC è stata sempre sotto al 10%.
Il gas naturale è una parte considerevole del fabbisogno energetico totale mondiale. Tuttavia, negli ultimi anni, particolare attenzione è stata però dedicata al passaggio alle energie rinnovabili, tra cui l’uso dell’idrogeno. Infatti, per ridurre gli effetti del cambiamento climatico, il ruolo dell'idrogeno sarà molto importante. Un utilizzo immediato dell'idrogeno è la decarbonizzazione della rete del gas: essendo una molecola gassosa a condizioni atmosferiche, può essere utilizzato come diretto sostituto del gas naturale. In vari paesi sono iniziate delle sperimentazioni per implementare l'idrogeno nei gasdotti fino a una percentuale del 20%, consentendo una minore emissione di CO2. Con questo nuovo percorso delineato, emerge una nuova esigenza: la necessità di determinare la concentrazione di idrogeno nel gasdotto. Durante il dottorato è stato sviluppato un sensore gasocromico per idrogeno basato su film sottili di ossido di tungsteno ricoperti da nanoparticelle di metalli nobili (Au, Pt). È stato appurato che sensori costituiti da film cristallini ricoperti da nanoparticelle di platino mostrano le migliori prestazioni. Inoltre, specialmente nel caso dell'oro, nanoparticelle più piccole mostrano una migliore risposta all’idrogeno. Calcoli computazionali basati su calcoli DFT (Density Functional Theory) suggeriscono che ciò potrebbe essere correlato ai processi che si verificano all'interfaccia tra nanoparticella e WO3. Mentre il platino sembra catalizzare l'adsorbimento dissociativo dell'idrogeno sia eterolitico che omolitico, l'oro può catalizzare solo l'adsorbimento eterolitico. Queste evidenze, in combinazione con un'analisi della distribuzione delle cariche, spiegano sia l’inferiorità dell’oro rispetto al platino come catalizzatore, sia la dipendenza delle performance dalle dimensioni delle nanoparticelle. Infine, film cristallini di ossido di tungsteno rivestiti con nanoparticelle di platino hanno mostrato ottime prestazioni nel misurare idrogeno in metano. Con vari test, i sensori prodotti hanno dimostrato di avere eccellente accuratezza, ripetibilità e stabilità a lungo termine, con prestazioni indipendenti dal flusso di gas o dall'atmosfera utilizzata.My research work during the PhD was devoted to the development of optical gas sensors for two important constituents of natural gas: odorants and hydrogen. Odorants are added in natural gas because it is naturally colorless, tasteless and odorless. Therefore, before it is distributed to end-users, small amounts of thiols are added to assist in leak detection. The two most used odorants in Italian pipelines are TBM and THT. It is very important to measure these odorants: a too low concentration does not allow a person to detect if there is a leak, a too high concentration might alarm in vain. Currently, odorants in natural gas are measured with gas chromatography (GC). GC, however, has several flaws, such as high cost, routine maintenance and it requires a skilled technician to operate. Since both THT and TBM have a characteristic UV absorption spectrum, during this PhD project, a working prototype called MUDO (Mid-UV Detector for Odorants) that relies on UV absorption has been fabricated. The prototype comprises a deuterium lamp as a source of UV light, two optical fibers, two collimators, a gas flow cell and a UV Spectrometer. Moreover, two programs were written in python to operate the hardware, to collect spectra and to compute the concentrations. With MUDO, two on-site tests were made, one in Vicenza, where the gas network is odorized with THT, and one in Milan, where the gas network is odorized with TBM. These tests were performed in parallel to a GC, used as a reference. The results acknowledged MUDO as a valid method to measure odorant concentration in natural gas, as the difference between the values measured by MUDO and by GC managed to always stay between ±10%. Natural gas is a considerable portion of the world’s total energy supply. However, in the last few years, particular attention has been given to the transition to renewable energy, including the use of hydrogen. Indeed, to reduce the effects of climate change, the role of hydrogen will be very important. An immediate use for hydrogen is the decarbonization of heat: as it is a gaseous molecule at atmospheric conditions, it can be used as a direct replacement for natural gas within the gas grid. In various countries, trials have started to implement hydrogen in natural gas pipelines up to a percentage of 20% mol. This enables a lower carbon emission, without customers requiring disruptive and expensive changes in their homes. With this new path outlined, a new need emerges: the need to correctly determine the concentration of hydrogen in the natural gas pipeline. During this PhD, a gasochromic sensor for hydrogen based on noble metal (Au, Pt) nanoparticles covered Tungsten Oxide thin film was developed. Sensing performances are strongly influenced by the crystal structure and the catalyst used, with Pt coated crystalline tungsten oxide resulting as best. Nanoparticle’s dimensions, especially in the case of gold, seem to play a role in the mechanism, with smaller NPs displaying better H2 intake. Computational insights based on Density Functional Theory calculations suggest that this could be related to the processes occurring at the nanoparticle-WO3 interface. While platinum allows both heterolytic (i.e. at the interface) and homolytic (i.e. only on the metal) hydrogen dissociative adsorption, gold can catalyze only heterolytic absorption. These evidences, in combination with an analysis of the charges distribution, explain both the inferior sensing performances of Au compared to Pt and the strong dependance of sensing performances on nanoparticle size, which dictates the extension nanoparticle-WO3 interface. Finally, Pt NPs coated crystalline tungsten oxide thin films displayed excellent hydrogen sensing performances in methane. With various tests, the sensor proved to have excellent accuracy, repeatability and long term stability, with performances relatively independent from gas flow or atmosphere.
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Savadori, Simone. « Implementazione di una rete di sensori per il controllo di gas inquinanti nell'ambiente ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4390/.
Texte intégralRésumé :
Negli ultimi anni i progressi tecnologici in termini di miniaturizzazione elettronica, hanno permesso la realizzazione di componenti hardware ed in particolare di microprocessori e sensori dalle dimensioni ridottissime. Questo ha favorito la recente diffusione di reti di sensori wireless (Wireless Sensor Network) basate su sistemi embedded più o meno complessi ed applicate a settori di
mercato che vanno dalla domotica alle applicazioni industriali, fino al monitoraggio dei pazienti.
Lo scopo di questa tesi, svolta in collaborazione con la società Rinnova di Forlì, consiste nell’implementazione di un dimostratore che mostri la reale capacità di realizzare una rete WS che si appoggia su di un sistema embedded commerciale ed ampiamente diffuso come la piattaforma Arduino ed in grado di rilevare il livello di ammoniaca presente negli allevamenti di pollame. Tale gas infatti, se
presente in quantità notevole, provoca una dannosa alterazione comportamentale dei polli e risulta quindi un parametro molto importante da monitorare. Oltre al
sensore di ammoniaca, misurazione principale richiesta dal progetto, ne sono stati aggiunti uno per la temperatura ed uno per l’umidità.
L’architettura finale implementata è quella tipica di una rete a stella, in cui il master centrale colleziona a polling i dati provenienti dai sensori collegati agli
slave e li invia ad un server web, rendendoli accessibili mediante la rete Internet.
L’utente finale può così accedere alla pagina web da un qualunque PC dotato di connessione Internet, monitorare i dati dei sensori e soprattutto verificare quando il livello di ammoniaca supera la soglia di attenzione, potendo così intervenire immediatamente nell’allevamento per effettuare le dovute operazioni di pulizia.
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FREDDI, SONIA. « Sviluppo di piattaforme a base di carbonio nanostrutturato per applicazioni avanzate di gas sensing ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2022. http://hdl.handle.net/10280/117007.
Texte intégralRésumé :
Tra le applicazioni all'avanguardia di materiali a base di carbonio nanostrutturato, come grafene e nanotubi di carbonio (CNTs), l'analisi del respiro (i.e. breathomics), il monitoraggio ambientale e l'industria alimentare stanno oggigiorno sfidando la fisica, la chimica e l’ingegneria dei materiali a sviluppare piattaforme di sensori estremamente sensibili, affidabili e stabili, che siano in grado di rilevare piccolissime quantità (ordine dei ppb) di molecole di gas nell’ambiente che le circonda. In questa tesi, verrà presentato lo sviluppo di 6 piattaforme di sensori di gas. Queste piattaforme saranno sviluppate con carbonio nanostrutturato e avranno come scopo principale quello di discriminare potenziali patologie attraverso il riconoscimento di pattern molecolari presenti nel respiro esalato, nonché la loro possibile applicazione nel monitoraggio ambientale degli inquinanti e nell’industria alimentare.
Questo obbiettivo verrà realizzato sviluppando dapprima piattaforme a base di CNTs su un substrato di plastica o su silicio/ossido di silicio e successivamente a base di grafene su nitruro di silicio.
Verranno esplorati diversi metodi di funzionalizzazione sia per i CNTs che per il grafene, per aumentarne la sensitività, e verranno utilizzati diversi materiali per la funzionalizzazione, incluse nanoparticelle, molecole organiche o sali di diazonio.
Tecniche di spettroscopie Raman ed elettroniche unitamente a microscopia a forza atomica verranno utilizzare per caratterizzare i campioni, mentre le esposizioni di gas verranno effettuate in aria, condizione più simile a quella delle applicazioni finali dei sensori, cercando di indagare concentrazioni dei gas selezionati nel sub-ppm o di poche decine di ppm. L’analisi delle componenti principali (PCA) verrà utilizzata per testare le capacità di discriminazione dei gas delle piattaforme sviluppate.
Infine, uno dei nasi elettronici sviluppati verrà testato con il respiro esalato di soggetti sani o affetti da broncopneumopatie cronico ostruttive (COPD), dimostrando un’ottima capacità di discriminare e riconoscere le due classi di pazienti.Among forefront applications of nanostructured carbon materials such as graphene and nanotubes, breathomics, environmental monitoring and food industry are challenging physics, chemistry and device engineering to develop extremely sensitive, selective, and stable platform to recognize ppb amount of target molecules in the environment. In this thesis, the development of 6 platforms will be presented. The platforms are based on nanostructured carbon aimed mostly to discriminate potential pathologies through pattern recognition in molecular fingerprint of breath samples, but also for environmental monitoring or food industry applications. This objective will be realized through properly developed devices based first on CNTs on a plastic substrate or on silicon/silicon oxide substrate and then on graphene on silicon nitride. Different kinds of functionalization techniques of graphene and CNTs will be explored to enhance the sensitivity of the pristine layers, as well as different functionalization materials, going from nanoparticles to organic molecules or diazonium salt precursors. The characterization of the materials involves electron and Raman spectroscopies, as well as atomic force microscopy, while gas exposures are carried out in the lab environment, which is much closer to the destination of the developed sensors, trying to investigate a low-ppm range or sub-ppm range of the considered gases. The gas discrimination is assessed through principal component analysis (PCA). Finally, one of the developed devices is exposed to the exhaled breath of healthy subjects or patients affected by chronic obstructive pulmonary diseases (COPD), demonstrating a remarkable capability to discriminate between healthy and sick patients.
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Cortellazzi, Daniele. « Progetto e calibrazione di un dispositivo portatile per il monitoraggio della qualita dell'aria ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7549/.
Texte intégralRésumé :
Sviluppo di un prodotto per la misurazione di parametri ambientali legati alla qualità dell’ambiente in cui viviamo. Il dispositivo si struttura in moduli: una base comune comprendente tutti i componenti di elaborazione, visualizzazione, trasmissione e memorizzazione, unito a vari moduli sensore da collegare in base ai parametri che si vogliono monitorare.
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DOMAKOSKI, ANA CAROLINA. « Impiego di un array di sensori di gas e di tecniche gascromatografiche per lo studio di patologie e forme cellulari attraverso l'analisi di composti volatili rilasciati dai fluidi biologici ». Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2016. http://hdl.handle.net/2108/201857.
Texte intégralRésumé :
The present thesis describes the potentials that the volatile organic compounds (VOCs) have in diagnostics as well as the results achieved by using innovative analytical systems (such as SPME-GC/MS spectrometer and electronic nose instruments) to reveal pathologies, inflammatory processes, metabolic disorders, infections and degenerative cellular processes, also occurring in the early stages. Therefore, in collaboration with both clinicians and research groups of medicine and biology, chemistry and electronic engineering, three different experiments were carried out and here described. The first one was related to the application of both a homemade electronic nose (Department of Electronic Engineering of “Tor Vergata” University), based quartz crystal microbalances (QCM) differently coated with metal porphyrins (synthesized in the Laboratory of Chemistry of “Tor Vergata” University), and a SPME-GC/MS spectrometer to investigate the pattern of the volatile compounds of synovial fluids coming from several patients suffering from two different knee‟s rheumatic diseases (“Tor Vergata” General Hospital, Medicine Department). In this case a greater abundance of volatile compounds in OA than RA. The biomarkers for differential diagnosis between OA and RA are still defective. Through the analysis of the head space of the synovial fluid by NE, good discrimination was obtained between the different pathologies considered the results indicate that the VOC mixture in the synovial fluid of patients with OA is different from that of patients with RA. The second one involved a similar equipment, whereas the electronic nose contained an increased number of sensors, to investigate VOCs from living mice (i.e. breath, skin, urine, faeces) infected with erythrocytes containing different strains of plasmodium (Higher Health Institute, ISS). The results by Plasmodium berghei infection alters the profile of VOCs released, NE analysis of the entire murine volatiloma has led to a good discrimination between a group of healthy mice and one of malaria-affected rats. The GC/MS was detected by a set of VOCs whose concentration was statistically different between infected and uninfected mice. The last one provided an intriguing investigation, using the same instrumentation, on the pattern of volatile compounds from stem cell (specifically Induced Pluripotent Stem cell) in the different stages of differentiation (Department of Genetics). In each application, a suitable measurement protocol was arranged. All the results were treated with statistical analysis and multicomponent analysis. The results support the hypothesis that the volatile fraction of the metabolic profile changes along the differentiation process as a reflection of the variations occurring in the cells. The GC/MS shows a number of compounds that can discriminate between the various stages of differentiation. The NE shows good ability to discriminate between different cellular stages, from pluripotency to differentiated cells.
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DELLA, CIANA Michele. « Design, validation and future perspectives of a setup for operando DRIFT spectroscopy measurements on chemiresistive gas sensors ». Doctoral thesis, Università degli studi di Ferrara, 2022. http://hdl.handle.net/11392/2481665.
Texte intégralRésumé :
In questa tesi di dottorato è presentato lo sviluppo di un sistema operando per la caratterizzazione di sensori di gas chemiresistivi utilizzando spettroscopia di luce infrarossa (IR) diffusa (DRIFT).
L'attività di ricerca è stata focalizzata sullo sviluppo parallelo della camera test da implementare nello spettrometro e dell'elettronica associata per l'acquisizione e l'elaborazione dei segnali.
La camera di misura è stata progettata per essere compatibile con lo spettrometro a trasformata di Fourier IR Vertex V70 (Bruker) dotato di accessorio DRIFT Praying Mantis (Harrick Scientific).
Per il design meccanico della camera test si è fatto utilizzo sia delle tecnologie di stampa 3D, sia delle tecniche di lavorazione tradizionali di fresatura a controllo numerico.
L'elettronica del sistema è stata progettata per caratterizzare elettricamente sensori di gas chemiresistivi in un ampio intervallo dei parametri di misura (i.e., resistenza e temperatura operativa del film sensibile, umidità e temperatura dell'ambiente di lavoro).
Al sistema è associato un software, sviluppato in Java, che semplifica la caratterizzazione elettrica dei sensori, automatizzando alcune procedure di misura, come l'acquisizione della caratteristica corrente-tensione e della caratteristica corrente-temperatura.
Un sensore chemiresistivo è normalmente approssimato ad una resistenza ideale. L'implementazione di queste caratterizzazioni nell'elettronica di misura permette quindi di tenere in considerazione la non linearità di questa tipologia di dispositivi.
Il setup è stato validato sia utilizzando un sensore a base di un ossido metallico ampiamente utilizzato (ossido di stagno), sia caratterizzando un sensore basato su un innovativo semiconduttore non-ossido (carburo di silicio).
Nel primo caso il sensore a base di ossido di stagno è stato esposto a monossido di carbonio (CO) e idrogeno (H_2) in differenti condizioni termodinamiche (e.g. temperatura di lavoro, potenziale applicato al film sensibile e composizione dell'atmosfera) ed è stata studiata la correlazione fra lo spettro DRIFT e le proprietà elettriche del film sensibile.
L'analisi ha dimostrato la conformità del sistema operando per studiare l'interazione solido-gas, approfondendo la cinetica sulla superficie del film sensibile.
Il successivo studio riguardante dispositivi a base di carburo di silicio ha permesso di investigare il meccanismo di sensing nel rilevamento dell'anidride solforosa in condizioni di umidità controllata, monitorando lo stato di ossidazione che porta alla formazione di una core-shell SiC-SiO_xC.
Infine sono presentate due estensioni al sistema che permettono rispettivamente di effettuare misure operando DRIFT sia direttamente su polveri funzionali nano-strutturate in temperatura e sia su un sensore foto-attivato.This Ph.D. thesis presents the development of an operando setup for the characterization of chemiresistive gas sensors using diffused infrared light spectroscopy (DRIFT). The research activities were focused on the parallel development of a testing chamber to include in the spectrometer and the coupled electronics for the acquisition and the analysis of the electric signals. The measuring chamber was designed to be compatible with a Fourier transform IR spectrometer Vertex V70 (Bruker) equipped with the DRIFT praying Mantis accessory (Harric scientific). For the mechanical design of the chamber, it was exploited both 3D printing technologies and traditional numerical control manufacturing techniques. The electronics of the system was designed to electrically characterize chemiresistive gas sensors in a wide range of parameters (i.e., resistance and working temperature of the sensing film, relative humidity and temperature of the measuring environment). The system is managed by a software, written in Java, that simplifies the electrical characterization of the sensors, automating some measurement procedures, such as the acquisition of the current-voltage and current-temperature characteristics of the devices under test. A chemiresistive gas sensor is usually approximated by an ideal resistor, and the implementation of these characteristics in the measuring electronics allows to consider the non-linearity of this type of devices. The setup was validated both characterizing a metal-oxide based gas sensor (tin dioxide) and investigative a innovative gas sensor based on a non-oxide semiconductor (silicon carbide). In the first case, the sensor based on tin dioxide was exposed to carbon monoxide (CO) and hydrogen (H_2) in different thermodynamic conditions (e.g., working temperature and potential applied to the sensing film, composition of the atmosphere). It was studied the correlation between the DRIFT spectrum and the electrical properties of the sensing film. This analysis has demonstrated the compliance of the operando system to study the gas-solid interactions by deepening the kinetics on the surface of the sensing film. Afterward, the investigation on the devices based on silicon carbide nanoparticles allowed to understand the sensing mechanism of the sulfur dioxide detection under controlled humidity conditions. It was also monitored the oxidation state of the film, which leads to the formation of a SiC-SiO_xC core-shell. Finally, two extensions to the system are presented, that allow to perform operando DRIFT measurements at high temperature directly on powders and on photo-activated sensors, respectively.
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CICIOTTI, FULVIO. « Oscillator-Based CMOS Readout Interfaces for Gas Sensing Applications ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/241089.
Texte intégralRésumé :
Il rilevamento di gas tossici e pericolosi è sempre stato necessario per motivi di sicurezza. Negli ultimi anni, in particolare, l’attenzione per lo sviluppo di sistemi portatili e a basso costo per il rilevamento dei gas è aumentata notevolmente. Questa tesi presenta circuiti CMOS versatili, veloci, ad alta precisione e basso consumo per applicazioni portatili di rilevamento di gas. I sensori target sono i Metal Oxide Semiconductor (MOX). Questi sensori sono ampiamente utilizzati per la loro intrinseca compatibilità con le tecnologie MEMS integrate. Le tipologie di lettura scelte sono basate su un oscillatore controllato dalla resistenza del sensore stessa, in modo da ottenere una conversione resistenza-tempo. Ciò garantisce un ampio range dinamico, una buona precisione e la capacità di far fronte alle grandi variazioni di resistenza del sensore MOX. Quattro diversi prototipi sono stati sviluppati e testati con successo. Sono state anche eseguite misurazioni chimiche con un vero sensore SnO2 MOX, validando i risultati ottenuti. Le misure hanno mostrato come il sensore e l’interfaccia sia in grado di rilevare fino a 5ppm di CO in aria. Gli ASIC sono in grado di coprire 128 dB di DR a 4Hz di output data rate digitale, o 148 dB a 0.4Hz, garantendo un errore relativo percentuale sempre migliore dello 0,4% (SNDR> 48 dB). Le prestazioni target sono state raggiunte con aggressive strategie di progettazione e ottimizzazione a livello di sistema. È stata utilizzata una tecnologia CMOS a 130nm fornita da Infineon Technologies AG. La scelta di un nodo tecnologico così scalato (rispetto alle tipiche implementazioni in questo settore) ha consentito di ridurre ulteriormente i consumi fino a circa 450 μA. Inoltre, questo lavoro introduce la possibilità di utilizzare la stessa architettura basata su oscillatore per eseguire la lettura di sensori capacitivi. I risultati delle misurazioni con sensori capacitivi MEMS hanno mostrato 116 dB di DR, con un SNR di 74 dB a 10Hz di velocità di trasmissione dati digitale. Le architetture sviluppate in questa tesi sono compatibili con gli standard moderni nel settore del rilevamento del gas per dispositivi portatili.Detection of toxic and dangerous gases has always been a need for safety purpose and, in recent years, portable and low-cost gas sensing systems are becoming of main interest. This thesis presents fast, high precision, low-power, versatile CMOS interface circuits for portable gas sensing applications. The target sensors are Metal Oxide Semiconductor (MOX) sensors which are widely used due to their inherent compatibility with integrated MEMS technologies. The chosen readout typologies are based on the time-domain Resistor-Controlled Oscillator. This guarantees wide dynamic range, good precision and the ability to cope with the large MOX sensor resistance variations. Four different prototypes have been successfully developed and tested. Chemical measurements with a real SnO2 MOX sensor have also been performed to validate the results, showing a minimum CO detection capability in ambient air of 5 ppm. The ASICs are able to cover 128 dB of DR at 4 Hz of digital output data rate, or 148 dB at 0.4 Hz, while providing a relative error always better than 0.4% (SNDR >48 dB). Target performances have been achieved with aggressive design strategies and system-level optimization, and using a scaled (compared to typical implementations in this field) 130nm CMOS technology provided by Infineon Technologies AG. Power consumption is about 450 μA. Moreover, this work introduces the possibility to use the same oscillator-based architecture to perform capacitive sensors readout. Measurement results with capacitive MEMS sensors have shown 116 dB of DR in CSENS mode, with an SNR of 74 dB at 10 Hz of digital output data rate. The architectures developed in this thesis are compatible with the modern standards in the portable gas sensing industry.
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CERVI, Alan. « CARATTERIZZAZIONE ELETTRICA E SPETTROSCOPICA AD IMPEDENZA DI OSSIDI METALLICI NANOSTRUTTURATI PER IL RILEVAMENTO DI ALCANI VOLATILI ». Doctoral thesis, Università degli studi di Ferrara, 2009. http://hdl.handle.net/11392/2389138.
Texte intégralRésumé :
Chemoresistive gas sensors using semiconductor metal-oxides have proven to be excellent in important characteristics such as sensitivity, long-term stability, robustness and price. Solid solutions of mixed Sn and Ti oxides have shown promising results in combining the properties of the separate components. Basic science of these mixed oxides is far from being satisfactorily elucidated. Further progress in basic understanding is required to establish the principles to operate them as gas sensors.
Knowledge of the space charge width of the nanostructured powder grains is needed for the comparison of the mean grain radius to determine sensing properties of the nanostructure. A new method has been addressed using impedance spectroscopy technique to estimate the electric permittivity of these Sn and Ti oxides, which is fundamental for the determination of the space charge width and capacitive response.
A study of the sensing properties of chemoresistive metal-oxides vs. light alkanes has been undertaken under dry and wet conditions and even in presence of ethanol. Screen-printed films of pure Sn and Ti oxides and solid solutions of mixed Sn and Ti oxides have been selected for the purpose. It has been demonstrated that the films are capable of detecting 500ppm of methane or 100ppm of other light alkanes under either dry or wet condition, i.e. concentrations two levels by far lower than the alarm thresholds for such gases. Information about the working mechanism of chemical reactions on the surface has been discussed under either dry or wet condition. Ethanol is known to be a harmful interfering gas, though its concentration can be reduced to values lower than 10ppm by proper activated carbon filtering. It has been shown that, even in presence of 10ppm of ethanol, the films steadily responded to alkanes.
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Angelini, Ares. « Misura UHF (Ultra High Frequency) delle scariche parziali nei sistemi isolati a gas : metodologie per la verifica della sensibilità di misura ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11619/.
Texte intégralRésumé :
Le apparecchiature di manovra tramite isolamento a gas (GIS) sono in funzione da più di 45 anni e hanno dimostrato un alto livello di affidabilità, con tassi di difetto molto bassi.
Tuttavia, il riscontro pratico indica che alcuni dei guasti che si verificano durante il servizio sono legati a difetti del sistema di isolamento. Molti di questi difetti possono essere rilevati tramite diagnostica con scariche parziali (PD).
Per la rilevazione PD, viene utilizzato il metodo UHF perché meno sensibile ai disturbi e quindi più facile da gestire in confronto al metodo convenzionale secondo IEC 60270.
Un rapporto di Electra pubblicato nel 1999 dal CIGRE Task Force 15/33.03.05 descrive la procedura in due fasi per la verifica della sensibilità del sistema UHF in modo molto generale. Dopo 15 anni dalla sua applicazione, è diventata necessaria una descrizione più dettagliata, sia su misure necessarie al test di laboratorio (Passaggio 1) che sul test in loco (Passaggio 2).
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MAZZONE, EMILIANO. « Un approccio completo alla rilevazione di gas nocivi ». Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/480.
Texte intégralRésumé :
Il progetto di ricerca discusso in questa tesi è suddiviso in due line principali:
• la realizzazione di un database sullo stato dell’arte dei sensori di gas;
• lo Sviluppo di prototipi di sensori innovativi per la rilevazione del monossido di carbonio e
del DMMP.
La suddivisione delle attività è mirata a fornire una descrizione completa delle tecniche di
rilevazione di gas nocivi, partendo dall’analisi dello stato dell’arte e dei principi di funzionamento
fino al progetto, realizzazione e test di prototipi basati su tecniche di traduzione innovative.
Lo sviluppo del database, iniziato con la definizione di un modello dell’informazione e proseguito
con la realizzazione dell’architettura, ha portato alla realizzazione di oltre 1000 file che descrivono i
vari aspetti delle più comuni tecniche di traduzione utilizzate nella rilevazione di gas.
La seconda linea di ricerca ha portato allo Sviluppo di prototipi di sensori per la rilevazione di CO e
DMMP.
La scelta del monossido di carbonio come gas target è stata dettata dalla elevata tossicità del
composto e dalla necessità di sviluppare sensori più efficienti rispetto a quelli attualmente presenti
sul mercato.
Lo strato sensibile è stato realizzato con Porfirine di Ferro, di composizione analoga a quelle
presenti nella molecola dell’emoglobina, per utilizzare un meccanismo di interazione simile a
quello che in natura porta ai fenomeni di avvelenamento da CO.
La tecnica di trasduzione scelta è basata su microbilance al quarzo (QMB), per poter rilevare il gas
di interesse attraverso variazioni di massa del dispositivo sensibile.
La qualità dei primi risultati ottenuti ha spinto verso la realizzazione di un dimostratore, punto di
partenza per un futuro Sviluppo a livello di produzione industriale.
Le possibili aree di applicazione di un sensore di questo tipo possono essere individuate in quei
settori in cui è necessario stimare i livelli di esposizione al monossido di carbonio durante le attività
lavorative.
Il secondo composto di interesse è stato scelto in base a due considerazioni fondamentali: in primo
luogo a causa del massiccio impiego a livello industriale, poi per le proprietà chimico-fisiche che lo
rendono simulante del Sarin.
La scelta dello strato sensibile (complessi di ioni lantanidi) è basata su studi preliminari
sull’interazione tra questo tipo di complessi e sostanze chimiche che contengono gruppi P=O.
La tecnica di trasduzione, anche in questo caso a variazione di massa, è stata implementata
utilizzando dispositivi ad onda acustica superficiale (SAW).
I risultati di questo studio sono stati molto incoraggianti, anche se un futuro sviluppo di tipo
commerciale non può prescindere da un maggiore controllo delle condizioni sperimentali.
Infine, è stato condotto uno studio di fattibilità sulla possibilità di realizzare biosensori basati su
aminoacidi e microbalance al quarzo per la rilevazione di monossido di carbonio e DMMP.
La fase sperimentale è stata condotta utilizzando un naso elettronico ed ha dimostrato che questo
tipo di approccio potrà portare in futuro alla realizzazione di sensori dotati di ottime caratteristiche
di sensibilità, selettività e stabilità.
In conclusione, gli obiettivi perseguiti durante il periodo del Corso di Dottorato sono stati raggiunti
con risultati soddisfacenti, tanto che è possible pensare ad un utilizzo a livello industriale sia del
database che dei sensori di gas.
Le attività svolte durante il Corso di Dottorato sono inserite nell’ambito del Progetto di Innovazione
Industriale “Materiali e Tecnologie Innovative per Settori Avanzati”, in collaborazione con il
Centro Sviluppo Materiali S.p.A.The research project discussed within this thesis was split into two main lines: • realization of a database on the state of the art of gas sensors; • development of innovative sensors prototypes for carbon monoxide and DMMP detection. The strategy behind the above separation was to perform a comprehensive approach to dangerous gases detection, starting from a profound analysis of the state-of-the-art to designing and testing prototypes to implement new transduction techniques for detecting the analytes with high sensibility. Realization of the database required defining the model of information and implementing the architecture that up to now contains more that 1000 descriptive files concerning the most popular transduction techniques for gas analysis. The second activities line was aimed at developing CO and DMMP sensors prototypes. Carbon Monoxide was selected as a target mainly due to its high toxicity, which claims for better detecting systems. The innovative approach to CO sensing was based on a biomimetic technology which uses the high affinity of iron ions towards CO molecules for enhancing the sensor’s sensitivity and selectivity. The sensing layers were Fe-porphyrins, analogous the basic compounds of haemoglobin. Then, the research line intended to use the biological effect of CO poisoning to develop a new kind of sensor. The selected transduction technique is based on mass changes, thus using QMB devices for sensing. The preliminary results where good enough that an industrial demo unit has been realized with the objective of becoming the starting point for further industrial development. One of the main application areas of such a device can be envisaged in assessing the exposure to unknown amounts of CO during work activities. The second target compound was chosen according to two main considerations: first of all because of its large industrial use, then because of its chemical properties a simulant of the nerve agent Sarin. The composition of the sensitive layers (complexes of lanthanide ions), was chosen as a consequence of preliminary studies of the interaction mechanisms between lanthanide complexes and chemical compounds containing a P=O group. The transduction elements were Surface Acoustic Wave devices (SAW) that allowed implementing a mass change technique. Also the results of this study were encouraging enough, even though some additional work on controlling the environmental parameters and experimental conditions should be done. Then, great attention was devoted to studying the feasibility of biosensors based on amino acids and QMB, for detecting CO and DMMP. These experiments, carried out using an electronic nose, showed that this approach is promising for obtaining highly sensitive, selective and stable sensors. Finally, the goals have been reached with satisfactory results and a commercial exploitation of the prototypes, from the database to the biosensing devices, can be envisaged with a certain degree of confidence. The activities developed during this PhD course have been carried out within the frame of the “Innovative Materials and Technologies for Advanced Sectors” Industrial innovation project, in cooperation within the Centro Sviluppo Materiali S.p.A.
Livres sur le sujet "Sensori di gas"
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Zhan chang jian shi di mian chuan gan qi xi tong ji shu yu ying yong. Beijing : Beijing li gong da xue chu ban she, 2011.
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editor, Peng Wenfu, et Zeng Qiongyi editor, dir. Xiang xiang li da bao fa ! : Hai zi de di yi tang wu gan ti yan ke = Imagination burst : sensory play. Xinbei Shi : Jiao yu zhi you wen hua, 2015.
Trouver le texte intégralActes de conférences sur le sujet "Sensori di gas"
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Ghosh, P. K., et A. Sarkar. « Biomaterial based sulphur di oxide gas sensor ». Dans PROCEEDING OF INTERNATIONAL CONFERENCE ON RECENT TRENDS IN APPLIED PHYSICS AND MATERIAL SCIENCE : RAM 2013. AIP, 2013. http://dx.doi.org/10.1063/1.4810647.
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Ebrahimpour Tolouei, Nadia, Md Ebrahim Khalil Bhuiyan, Michael Hankins et Mohammad Shavezipur. « Development of a MEMS Chemical Sensor for Detection of Phthalates in Juice Using Electrochemical Impedance Spectroscopy ». Dans ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22185.
Texte intégralRésumé :
Abstract Presence of toxic chemicals in food products due to the use of different synthetic materials in food packages may cause long-term health hazard. Addition of chemical components such as phthalate family (for instance, Di(2-ethylhexyl) phthalate, DEHP) to plastics may result in diffusion of these materials in food specially in liquids such as bottled soft drink, water and juice. In this work, we present a chemical sensor that can detect DEHP in orange juice at extremely low concentrations. The sensor is made of two interdigitated electrodes, and electrochemical impedance spectroscopy (EIS) is used for the detection. Sensors with different overall dimensions and finger/gap sizes were fabricated using a polycrystalline silicon standard foundry. For simplification of the experiments, low concentration of citric acid in water (similar to orange juice) is used to represent the orange juice. The sensors are exposed to different concentrations of DEHP and their Nyquist and impedance-frequency plots are studied. The experimental data shows that the sensors can distinctly capture low concentrations of DEHP in the juice solution. An electrical model is developed that can simulate the frequency response of the system containing the sensor and the solution. The model includes dynamic physical parameters such as double-layer capacitance, solution resistance and Warburg impedance that can be used in detection. EIS curves fit to experimental data shows that the model well fits the experimental data.
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Ebrahimpour Tolouei, Nadia, Shima Ghamari et Mohammad Shavezipur. « Investigation of the Effect of Native Oxide Layer on Performance of Interdigitated Impedance-Based Silicon Biochemical Sensors ». Dans ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22207.
Texte intégralRésumé :
Abstract Chemical and biological detection using Electrochemistry Impedance Spectroscopy (EIS) highly depends on the electrical characteristics of the electrodes used in the measurement process. In this work, the effect of surface coating on behavior of interdigitated impedance-based biochemical sensors is studied. Two interdigitated sensors with the same geometry and different electrode materials are fabricated using a standard process. One electrode is made of gold and the other electrode is made of polycrystalline silicon covered with a thin layer of native silicon dioxide. Different concentrations of di(2-ethylhexyl) phthalate (DEHP) in water are used and the Nyquist responses of the two sensors exposed to these solutions are obtained. The measurement results show that at high frequency both sensors form double-layer capacitance values on their electrode surfaces, however, the silicon sensor has a much lower double-layer capacitance values, because formation of oxide layer adds to the gap between charges at the interface of the electrode and the solution. Moreover, comparing the low frequency regions of the Nyquist plots for two sensors shows that the presence of oxide layer affects the Warburg effect and the charge diffusion near the surface of the electrode, creating an extra capacitive element in series with the diffusion effect. The results of this work may be extended to other interdigitated biochemical sensors that may have other sources of contamination on their surfaces.
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Wang, Jianjing, Mohammad H. Hedayati, Dawei Liu, Salah-Eddine Adami, Harry C. P. Dymond, Jeremy J. O. Dalton et Bernard H. Stark. « Infinity Sensor : Temperature Sensing in GaN Power Devices using Peak di/dt ». Dans 2018 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2018. http://dx.doi.org/10.1109/ecce.2018.8558287.
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Dutta, Prashanta. « A Conductivity Based Microfluidic Flow Sensor ». Dans ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13636.
Texte intégralRésumé :
A conductivity based on-chip flow sensor is introduced to measure the velocity of liquid-gas interface in microchannels for lab-on-a-chip applications. This sensor is used to evaluate the performance of planar electrokinetic micropumps formed on hybrid poly-di-methyl-siloxane (PDMS)-glass platform. In this study, the micropump thickness is varied between 3.5 and 10 microns, and the externally applied electric field of electrokinetic pump is ranged from 100 V/mm to 200 V/mm. For all channel dimensions and for all electric fields, fairly repeatable flow results are obtained from the speed of liquid-gas interface. Flow results obtained from this interface tracking method are compared to those of other existing flow measuring technique. The maximum error of this micro flow sensor is less than 5%, even in ultra low flow velocity.
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Gaetani, P., G. Persico, V. Dossena et C. Osnaghi. « Investigation of the Flow Field in a HP Turbine Stage for Two Stator-Rotor Axial Gaps : Part I — 3D Time-Averaged Flow Field ». Dans ASME Turbo Expo 2006 : Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90553.
Texte intégralRésumé :
An extensive experimental analysis on the subject of unsteady flow field in high pressure turbine stages was carried out at the Laboratorio di Fluidodinamica delle Macchine (LFM) of Politecnico di Milano. The research stage represents a typical modern HP gas turbine stage designed by means of 3D techniques, characterised by a leaned stator and a bowed rotor and operating in high subsonic regime. The first part of the program concerns the analysis of the steady flow field in the stator-rotor axial gap by means of a conventional five-hole probe and a temperature sensor. Measurements were carried out on eight planes located at different axial positions allowing the complete definition of steady flow field both in absolute and relative frame of reference. The evolution of the main flow structures, such as secondary flows and vane wakes, downstream of the stator are here presented and discussed in order to evidence the stator aerodynamic performance and, in particular, the different flow field approaching the rotor blade row for the two axial gaps. This results set will support the discussion of the unsteady stator-rotor effects presented in paper Part II. Furthermore, 3D time-averaged measurements downstream of the rotor were carried out at one axial distance and for two stator-rotor axial gaps. The position of the probe with respect to the stator blades is changed by means of rotating the stator in circumferential direction, in order to describe possible effects of the non-uniformity of the stator exit flow field downstream of the stage. Both flow fields, measured for the nominal and for a very large stator-rotor axial gap, are discussed and results show the persistence of some stator flow structures downstream of the rotor, in particular for the minimum axial gap. Eventually the flow fields are compared to evidence the effect of the stator-rotor axial gap on the stage performance from a time-averaged point of view.
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Ling, Kuok Hsu, et Hapiz Zulkiply. « Hydrocarbon Saturation Determination in Case of Total Losses : Invasion Profile Modelling with Dual Resistivity – A Possible Application in PMCD Drilling ». Dans Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31353-ms.
Texte intégralRésumé :
Abstract Objectives/Scope Formation evaluation and appraisal in Central Luconia carbonate reef is challenging when drilling operation change from conventional drilling to pressurised mud cap drilling (PMCD). PMCD drilling has always been the choice to deal with unmanageable losses condition. It is normally applied in carbonate reservoir with karst and vugs. Under this drilling condition, annular pressure and surface pressure is maintained above the formation that is able to take the cuttings and fluids. At the same time, light annular fluid is pumped down the annulus to maintain hole fill and avoid gas migration. Seawater, acts as sacrificial mud is pumped down the drill string to cool the bit and to transport the cuttings to loss zones. Meanwhile, for an exploration well, the primary objective is to prove hydrocarbon presence and hydrocarbon fluid contact through logging while drilling (LWD) as wireline logging is not favourable from operational perspective. One of the key challenges of interpreting hydrocarbon saturation in PMCD operation is suppression of resistivity value due to sea-water invasion. Indeed, with PMCD, the well is appeared to have high water saturation even though 1 MHz phase shift 36" spacing deep phase resistivity is used in the interpretation. However, this is inconsistent with gas kick occurred at the top of carbonate or gas shows prior to conversion from conventional drilling to PMCD operation. Another observation of resistivity log response in PMCD drilling is that the phase shift resistivity from different sensor spacing (6", 12", 24" and 36", with smaller number indicate shallower depth of investigation, and higher number indicate deeper depth of investigation) appears to have separation, which indicates invasion profile which happens at one time-frame. Although 1D inversion for true resistivity (Rt) can be carried out with multiple sensor spacing phase resistivity and invasion diameter (Di) as inputs, the inversion result does not yield satisfactory result that match pre-PMCD resistivity value. The objective of the paper/ abstract is to highlight the benefits or running dual – resistivity in LWD bottom-hole assembly (BHA) in PMCD well to capture time-lapse resistivity measurement, estimate Rt which is time-dependant and pin-pointing gas-water contact in the exploration/ appraisal wells. This new proposed concept and methodology is still at its early stage, yet designed to make better decision during operational time. Such an approach will provide benefits to petrophysics community in the PMCD well interpretation with minimal incremental cost.
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Sammartano, Giulia, Mattia Previtali et Fabrizio Banfi. « PARAMETRIC GENERATION IN HBIM WORKFLOWS FOR SLAM-BASED DATA : DISCUSSING EXPECTATIONS ON SUITABILITY AND ACCURACY ». Dans ARQUEOLÓGICA 2.0 - 9th International Congress & 3rd GEORES - GEOmatics and pREServation. Editorial Universitat Politécnica de Valéncia : Editorial Universitat Politécnica de Valéncia, 2021. http://dx.doi.org/10.4995/arqueologica9.2021.12155.
Texte intégralRésumé :
In the wide framework of Scan-to-BIM 3D modelling procedures, the complexity of the architectural heritage and its components is evidencing a gap of best practices and specification in the HBIM-modeling and thus it is requiring important considerations about the modelling strategies and protocols between the requested level of detail (LOD), the expect accuracy and above all the actual use-oriented requirements. Several works are largely focusing on developing workflows for traditional static LiDAR scanning sensors. However, the chance to benefit from on-site faster data acquisition is needful at times, and procedures are directing toward rapid mapping 3D approaches, evolving from traditional static scanning toward MMS (Mobile Mapping Systems) based on SLAM technology (Simultaneous Localization and Mapping) algorithms implemented in portable devices. The potential of these solutions can contribute to increase a massive cost-effective documentation, and also in view of BIM-HBIM modelling generation, and this needs further researches. At the same time, the descriptive capabilities of this class of portable scanners do not reach the precision of the static solutions. Many time-cost balance evaluations towards an analysis of geometry, grade of generation (GOG) and details can be thus conducted. This paper presents a first comparison between TLS (Faro Focus 3D) and hand-held scanner Zeb Revo (by GeoSLAM) of the entire workflow (from raw data acquisition up to parametric modeling) focusing on the Bramante’s Canonica Court in the Basilica di Sant’Ambrogio. First, the two raw data are compared, considering geometric features (data density, precision, possibility to detect edges, details and accurate curvature). Then, some well-established modelling procedures developed for TLS data, as triangulation mesh and NURBS generation, are applied to MMS point cloud to identify their suitability. Different elements belonging to the architectural structure hierarchy are considered in a multi-scale perspective: the vaulted system of the porch, the columns and the arches of the porch with their different architectural elements.
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Jella, Sandeep, Gilles Bourque, Pierre Gauthier, Philippe Versailles, Jeffrey Bergthorson, Ji-Woong Park, Tianfeng Lu, Snehashish Panigrahy et Henry Curran. « Analysis of Autoignition Chemistry in Aeroderivative Premixers at Engine Conditions ». Dans ASME Turbo Expo 2020 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15697.
Texte intégralRésumé :
Abstract The minimization of autoignition risk is critical to the design of premixers of high power aeroderivative gas turbines as an increased use of highly reactive future fuels (for example, hydrogen or higher hydrocarbons) is anticipated. Safety factors based on ignition delays of homogeneous mixtures, are generally used to guide the choice of a residence time for a given premixer. However, autoignition chemistry at aeroderivative conditions is fast (0.5–2 milliseconds) and can be initiated within typical premixer residence times. The analysis of what takes place in this short period necessarily involves the study of low-temperature autoignition precursor chemistry, but precursors can change with fuel and local reactivity. Chemical Explosive Modes are a natural alternative to study this as they can provide a measure of autoignition risk by considering the whole thermochemical state in the framework of an eigenvalue problem. When transport effects are included by coupling the evolution of the Chemical Explosive Modes to turbulence, it is possible to obtain a measure of spatial autoignition risk where both chemical (e.g. ignition delay) and aerodynamic (e.g. local residence time) influences are unified. In this article, we describe a method that couples Large Eddy Simulation to newly developed, reduced autoignition chemical kinetics to study autoignition precursors in an example pre-mixer representative of real life geometric complexity. A blend of pure methane and dimethyl ether (DME), a common fuel used for experimental autoignition studies, was transported using the reduced mechanism (38 species / 238 reactions) at engine conditions at increasing levels of DME concentration until exothermic autoignition kernels were formed. The resolution of species profiles was ensured by using a thickened flame model where dynamic thickening was carried out with a flame sensor modified to work with multi-stage heat release. The paper is outlined as follows: First, a reduced mechanism is constructed and validated for modeling methane as well as di-methyl ether (DME) autoignition. Second, sensitivity analysis is used to show the need for Chemical Explosive Modes. Third, the thickened flame model modifications are described and then applied to an example premixer at 25 bar / 890K preheat. The Chemical Explosive Mode analysis closely follows the large thermochemical changes in the premixer as a function of DME concentration and identifies where the premixer is sensitive and flame anchoring is likely to occur.