Call number: LD2668 .T4 1959 B87

No description available.

New millimeter wave interferometric, multifunctional sensors have been studied for industrial sensing applications: displacement measurement, liquid-level gauging and velocimetry. Two types of configuration were investigated to implement the sensor: homodyne and double-channel homodyne. Both sensors were integrated on planar structure using MMIC (Microwave Monolithic Integrated Circuit) and MIC (Microwave Integrated Circuit) technology for light, compact, and low-cost design. The displacement measurement results employing homodyne configuration show that sub-millimeter resolution in the order of 0.05 mm is feasible without correcting the non-linear phase response of the quadrature mixer. The double-channel homodyne configuration is proposed to suppress the nonlinearity of the quadrature mixer and to estimate the effect of frequency stability of a microwave signal source without the help of additional test equipment, at the loss of a slight increase of circuit complexity. The digital quadrature mixer is constituted by a quadrature-sampling signal processing technique and takes an important role in the elimination of conventional quadrature mixer's nonlinear phase response. Also, in the same displacement measurement, the radar sensor with the double-channel homodyne configuration provided a better resolution of 0.01mm, the best-reported resolution to date in terms of wavelength in the millimeter wave range, than the sensor employing simple homodyne configuration. Short-term stability of a microwave signal source, which is an important issue in phase sensitive measurement, is also considered through phase noise spectrum obtained by FFT spectral estimator at Intermediate Frequency (IF). The developed sensors demonstrate that displacement sensing with micron resolution and accuracy and high-resolution low-velocity measurement are feasible using millimeter-wave interferometer, which is attractive not only for displacement and velocity measurement, but also for other industrial sensing applications requiring very fine resolution and accuracy.

The project deals with a theoretical design of passive ultra-high frequency radio identification (UHF RFID) tag for the measurement of liquid levels. Liquid level has an influence on the input impedance of an RFID tag antenna. The changes of input impedance have been used to distinguish individual liquid levels. Furthermore, this project presents optimization methods for the highest efficiency of an UHF RFID tag in Matlab and it aims to design a suitable antenna within CST MICROWAVE STUDIO.

No / Tank flooding have become major causes of pollution both in residential and industrial areas majorly caused by overflows of water(mostly residential) and volatile poisonous industrial liquids from the storage tanks. An effective way of avoiding this problem will be by deploying some mechanism to monitor liquid level at each point in time and escalating unusual liquid levelsto a pump control circuit or to the relevant authorities for prompt action to avoid a flooding occurrence. This paper presents a low cost power efficient liquid level monitoring technique. Passive RFID tags are designed modelled and deployed, the signal variation from the Alien Reader Software are used to effectively estimate the level of liquid in any surface or underground tank. The experimental set up is presented and an expository presentation is made of the passive tag design, modelled and simulated and adopted for same application.

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Šio darbo tikslas – suprojektuoti ir išanalizuoti skysčio lygio valdymo sistemas su PI reguliatoriumi bei neraiškiosios logikos reguliatoriumi, atlikti imitacijas ir palyginti gautus rezultatus. Teorinėje dalyje apžvelgiamos skysčio lygio valdymo sistemos, jų pagrindiniai elementai. Taip pat išnagrinėjami sistemų valdymo ypatumai, naudojant neraiškiosios logikos ir PI reguliatorius. Tiriamojoje dalyje sudaryta: sistemos funkcinė schema, sistemos matematinis ir kompiuterinis modeliai. Atlikus procesų imitaciją nustatyta, kad sistemoje su PI reguliatoriumi pakeitus nuostatą dėl perreguliavimo gaunamos nepageidaujamos slėgio aukščio ir debito vertės. To išvengiama, naudojant neraiškiosios logikos reguliatorių. Darbo pabaigoje pateikiamos išvados. Darbą sudaro 7 dalys: įvadas, literatūros apie skysčio lygio valdymo sistemas analizė, tyrimo tikslas ir uždaviniai, teorinė dalis, tiriamoji dalis, išvados, literatūra. Darbo apimtis - 71 puslapiai be grafinės dalies, 53 iliustracijos, 6 lentelės, 40 bibliografinių šaltinių ir 4 internetinės prieigos. / The main goal of the thesis is to design and analyze liquid level control systems with a PI controller and a fuzzy logic controller, perform simulations and to compare the results. In the analytical part, liquid level control systems and main elements of liquid level control systems are overviewed. Also system control using PI and Fuzzy logic regulators is overviewed. In research part liquid level control system is projected practically. The research chapter consists of a functional scheme, mathematical and computer models design. The simulation of the system shows that changing the step size in the system with a PI controller results in unwanted total head and flow rate values because of an overshoot. This is avoided in the system with a fuzzy controller. At the end of the thesis there is a conclusions part. The work consists of seven parts: introduction, analysis of liquid level control system literature, main goal of the research, theory part, design part, conclusions, references. Work volume – 71 pages of text without appendixes, 53 illustrations, 6 tables, 40 bibliographical and 4 internet entries.

Idag är de flesta kemiska industrier försedda med system för nivåreglering. Dessa system syftar till att kontrollera vätskenivån i en behållare, trots störningar i form av smuts och skum. För denna process finns olika modeller av nivågivare på marknaden, men de flesta är antingen dyra eller kräver mycket rengöring och underhåll. Denna studie syftar till att undersöka om det är möjligt att mäta vätskenivån i en behållare som kan produceras till låg kostnad, och har en tillräcklig precision för att kunna användas som ett larm för att skydda doppvärmaren mot överhettning. Därför har ett konceptprov av kapacitiva nivågivare utförts där två varianter av kapacitiva nivågivare, etsad och tråd, har konstruerats och verifierats. Etsade varianter innefattar ett kopparlaminat med konfiguration av två fingerelektroder som rullats i ett PVDF-rör. Trådvarianten består av en partvinnad teflontråd som dragits på ett PVDF-rör. I både varianter varieras kapacitans med vattennivån beroende av avståndet mellan fingerelektroder i den etsade varianten och avståndet mellan teflontrådar i trådvarianten. Kapacitansen har beräknats för avståndet mellan fingerelektroder och mellan teflontrådar i form av en urladdningstid korrelerad med vattennivån. För denna process används en generatorkrets för fyrkantsvåg som byggts på en PCB. Resultatet av nivåmätning med båda varianter blev inte det önskade, men nivåmätningsfelet ligger inom ett acceptabelt intervall. Intervallet ligger mellan [+0,80,-0,52] för den etsade varianten och mellan [+1,02,-1,10] för trådvarianten. Det visar att den etsade varianten ger ett mindre nivåmätningsfel än trådvarianten. Nivåmätningsfelet kan minimeras genom att välja en lämpligare krets. / Today, most chemical industries have systems for level control. These systems aim to control the fluid level in a tank, despite dirt and foam disturbances. For this process there are different models of level sensors on the market, but most are either expensive or require a lot of cleaning and maintenance. This study aims to investigate whether it is possible to measure the level of fluid in a tank which can be produced at low cost and has sufficient precision to be used as an alarm to protect the immersion heaters from overheating. Therefore, a conceptual level of capacitive level sensors has been performed in which two variants of capacitive level sensors, etch and wire have been designed and verified. Etched variants include a copper-laminate with two finger electrode configurations rolled in a PVDF tube. The wire variant consists of a twisted Teflon wire drawn on a PVDF pipe. In both variations, capacitance with the water level varies depending on the distance between finger electrodes in the etched variant and the distance between the Teflon wires in the wire variant. The capacitance has been calculated for the distance between finger electrodes and between Teflon threads in the form of a discharge time correlated with the water level. For this process, a square wave generator circuit is built on a PCB. The result of level measurement with both variants did not get the desired, but the level measurement error is within an acceptable range. The interval is between [+ 0.80, -0.52] for the etched variant and between [+ 1.02, -1.10] for the wire variant. It shows that the etched variant gives a smaller level measurement error than the wire variant. The level measurement error can be minimized by selecting a more appropriate circuit.

Unconventional gas reservoirs in carbon dioxide sequestration activities is a relatively new and unexplored concept currently undergoing pilot scale testing. Sequestration has the potential for enhancing gas recovery while mitigating carbon dioxide to long term storage structures. Due to the extremely complex systems associated with these unconventional reservoirs, modeling becomes difficult to predict accurately. This thesis presents methods to increase the confidence of inferred parameter testing for unconventional reservoir sequestration in both seam coal bed methane wells and a shale wells. Various tests include the use of computed tomography coupled with Avizo modeling software, inductively coupled mass spectrometer fluid transport analysis, pressure transient build tests, liquid level detection, and desorption analysis coupled with cleat image analysis. Analyses of coals performed by both environmental scanning electron microscope (ESEM) and micro CT demonstrate that distributions of cleat porosity in coals are anisotropic and not correlated to the seam depth or location. ESEM is used with micro CT scanning to verify the results before and after the impregnation of the carbonic acid. The micro CT data in Avizo Fire© was used calculate an increase in cleat permeability by 25%. The increase of major flow pathways is caused by the dissolution of carbonates. Changes in the structures were observed qualitatively through ESEM and micro CT and quantitatively through Avizo and inductively coupled mass spectrometry. The results of comparative study between the cleat structures and the desorption of various seams indicate a trend in the cleat porosity and the desorption rate of the coals as well as the cleat porosity and the total gas in various seams. / Master of Science

The subject of this master‘s thesis is the issue of design of fiber optic sensor for min/max and continuous measurement of liquid level, which could be used for laboratory measurement of optoelectronics. The thesis is divided into the three parts, the first part deals with methods of retrieval level measurement using fiber optic sensors. The second part is made of plant design of optical fiber sensors, it is shown the implementation of measuring devices for liquid level measurement and measured transfer characteristics of the sensors developed. The last part is proposed for laboratory typing tasks using established preparation for teaching in the subject Optoelectronic sensors.