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Search results for: RESONANT SENSORS/ACTUATORS
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On the problem of optimised allocation of water quality sensors and actuators in DWDS
PublicationThe problems of water quality sensors and actuators placement in drinking water distribution systems (DWDSs) are addressed as separate, primarily. However, against the background of control systems theory, the nature of DWDSs dynamics indicates that these both problems are interdependent and impact the design of related water quality monitoring and control structures and algorithms. The research work presented in this paper is...
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Automatic tuning of a resonant circuit in wireless power supply systems for biomedical sensors
PublicationIn this paper, a tuning method of a resonant circuit suited for wireless powering of miniature endoscopic capsules is presented and discussed. The method allows for an automatic tuning of the resonant frequency and matching impedance of a full wave rectifier loading the resonant circuit. Thereby, the receiver tunes so as to obtain the highest power efficiency under given conditions of transmission. A prototype receiver for wireless...
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Time-domain measurement methods for R, L and C sensors based on aversatile direct sensor-to-microcontroller interface circuit
PublicationtIn the paper new time-domain measurement methods for determining values of resistive (R), inductive(L) and capacitive (C) sensors based on a versatile direct sensor-to-microcontroller interface for microcon-trollers with internal analog-to-digital converters (ADCs) and analog comparators (ACs) are presented.The interface circuit consists of a reference resistor Rrworking as a voltage divider, a given R, L or C sensorand a microcontroller...
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Interface circuit for impedance sensors using two specialized single-chip microsystems
PublicationW artykule przedstawiono obwód interfejsu przeznaczony do pomiaru parametrów impedancyjnych czujników lub celek pomiarowych instalowanych na obiektach technicznych. Umożliwia on pomiar modułu i argumentu impedancji w zakresie 10ohm
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A microcontroller system for measurement of three independent components in impedance sensors using a single square pulse
PublicationOpracowano nową metodę pomiaru w dziedzinie czasu i wyznaczania trzech składowych elementów modelu czujnika impedancyjnego oraz zaimplementowano ją w inteligentnym czujniku impedancji sterowanym 8-bitowym mikrokontrolerem. Metoda bazuje na pobudzeniu dzielnika napięciowego składającego się z rezystora pełniącego funkcję konwertera prąd na napięcie i z czujnika impedancji pojedynczym impulsem prostokątnym o czasie trwania T bezpośrednio...
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ZnO coated fiber optic microsphere sensor for the enhanced refractive index sensing
PublicationOptical fiber-based sensors are expected to become key components in the control of industrial processes,and the tuning and the enhancement of their sensing properties are crucial for the further developmentof this technology. Atomic Layer Deposition (ALD), a vapor phase technique allowing for the deposition ofconformal thin films, is particularly suited for the deposition of controllable thin films on challenging sub-strates....
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Polarization sensitive optical coherence tomography for technical materials investigation
PublicationZaprezentowano system optycznej tomografii koherentnej z analizą stanu polaryzacji światła. System umożliwia nieniszczące i bezkontaktowe badanie wewnętrznej struktury materiałów warstwowych. Przedstawiono zastosowaną metodę analizy stanu polaryzacji promieniowana wstecznie rozproszonego od badanego obiektu.
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ALD thin ZnO layer as an active medium in a fiber-optic Fabry-Perot interferometer
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Spectroscopic wireless sensor of hematocrit level
PublicationAn optical method for hematocrit measurement is presented. The sensor, designed and developed by authors, consists of a spectroscopic set-up and a microcontroller. The work of the sensor is based on measurement of intensity of two selected spectral bands. Tests confirmed the ability of the sensor to determine the hematocrit level with appropriate measurement accuracy. Measurement results can be transmitted via wireless module to...
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Polarization sensitive optical coherence tomography for technical materials investigation
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ALD thin ZnO layer as an active medium in a fiber-optic Fabry–Perot interferometer
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Synthetic jet actuator efficiency based on the reaction force measurement
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Analytical fluctuation enhanced sensing by resistive gas sensors
PublicationResistance fluctuations across polarised resistive gas sensors were studied in detail to evaluate sensor working conditions for detecting methane and ammonia at various concentrations. The 1/f noise component typically dominates other noise sources up to a few kHz and can be utilised to improve gas selectivity when compared with measurements of the sensor DC resistance. The Arrhenius plot was created and the activation energy for...
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Exhaled breath gas sensing using pristine and functionalized WO3 nanowire sensors enhanced by UV-light irradiation
PublicationThe development of advanced metal-oxide-semiconductor sensing technologies for the detection of Volatile Organic Compounds (VOCs) present in exhaled breath is of great importance for non-invasive, cheap and fast medical diagnostics. Our experimental studies investigate the effects of operating temperature selection and UV-light irradiation on improving the response of WO3 nanowire sensors towards exhaled breath exposure. Herein,...
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Gas selectivity enhancement by sampling-and-hold method in resistive gas sensors
PublicationCommercial resistive gas sensors exhibit various sensitivity to numerous gases when working at different elevated temperatures. That effect is due to a change in velocity of adsorption and desorption processes which can be modulated by temperature. Thus, to reach better selectivity of gas detection, we propose to apply a known method (called the sampling-and-hold method) of cooling down the gas sensor in the presence of the investigated...
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Fluctuation enhanced gas sensing with WO3-based nanoparticle gas sensors modulated by UV light at selected wavelengths
PublicationThe sensitivity and selectivity of WO3-based gas sensors can be enhanced by UV-irradiation-induced modulation, especially if different wavelengths are employed. We used fluctuation-enhanced gas sensing, based on measurements of resistance fluctuations in the gas sensor, to study the effects of such modulation on the noise intensity for ambient atmospheres of synthetic air without and with additions of small amounts of ethanol,...
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Formaldehyde detection with chemical gas sensors based on WO3 nanowires decorated with metal nanoparticles under dark conditions and UV light irradiation
PublicationWe report results of formaldehyde gas (CH2O) detection under dark conditions and UV light irradiation with pristine tungsten trioxide nanowires (WO3 NWs) and metal nanoparticles decorated WO3 NWs gas sensing layers. The resistive layers were deposited by one step aerosol assisted chemical vapor deposition (AACVD) on commercial alumina substrates with 10-pair interdigitated platinum electrodes. The elaborated gas sensors, based...
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Investigation of sensing mechanism of Nasicon electrocatalytic sensors in nitrogen dioxide and ammonia
PublicationIn this paper a sensing mechanism of Nasicon electrocatalytic sensor in nitrogen dioxide and ammonia is investigated. Both gases are environmentally hazardous and contain nitrogen atom in the molecule. However, it seems that their sensing mechanism in electrocatalytic sensor could be totally different. Namely, the maximum sensitivity for each gas was obtained at different temperatures. Also, different auxiliary layers are formed...
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An NO2 sensor based on WO3 thin films for automotive applications in the microwave frequency range
PublicationA microwave system dedicated to the detection of nitrogen dioxide in the harsh environment of the Norway highways is proposed. An optimized transmission line type of sensor coated with a tungsten trioxide thin film that changes its electrical properties under NO2 gas exposure is developed. The sensors' response (S) is given in °/GHz and it is calculated based on wideband measurements. The advantage of wideband measurements in comparison...
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Fluctuation-enhanced scent sensing using a single gas sensor
PublicationScent or aroma sensing during aromatherapy can be carried out by applying only a single resistance gas sensor (TGS - Taguchi Gas Sensors). This paper considers the efficiency of detection of essential oils by DC resistance and its fluctuations observed in TGS sensors. A detailed study has been conducted for scents emitted by five popular essential oils using three sensor types (TGS 2600, TGS 2602, TGS 823). The research was focused...
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Enhanced gas sensing by graphene-silicon Schottky diodes under UV irradiation
PublicationThe effect of ultraviolet (UV) or blue irradiation on graphene/n-doped silicon Schottky junctions toward gas sensing was investigated. Schottky diodes were subjected to oxidizing nitrogen dioxide (NO2, 1–3 ppm) and reducing tetrahydrofuran (THF, 50–200 ppm), showing significantly different responses observed on the currentvoltage (I-V) characteristics, especially under UV light (275 nm). NO2 affected the resistive part of the forward region...
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Oxygen biosensor based on carbon nanotubes directly grown on graphitic substrate
PublicationFilms of carbon nanotubes were synthesized on the graphitic substrates by CVD method in the presence of catalyst. Two different catalysts were used, that is nickel and iron, supported on graphitic substrates. The as-obtained nanotubes were analyzed by SEM imaging with EDX and Raman spectroscopy. The results revealed their multi-walled morphology. Free radical reaction was carried out in order to chemically functionalize synthesized...
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Functional fluorine-doped tin oxide coating for opto-electrochemical label-free biosensors
PublicationSensors operating in multiple domains, such as optical and electrochemical, offer properties making biosensing more effective than those working in a single domain. To combine such domains in one sensing device, materials offering a certain set of properties are required. Fluorine-doped tin oxide (FTO) thin film is discussed in this work as functional optically for guiding lossy modes and simultaneously electrochemically, i.e....
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Study of the NO2 sensing mechanism of PEDOT-RGO film using in situ Raman Spectroscopy
PublicationIn this work, the mechanism of the NO2 reaction with PEDOT-RGO composite film has been investigated via in situ Raman spectroscopy. Reduced graphene oxide (RGO), poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO) and poly(3,4-ethylenedioxytiophene)/ClO4− (PEDOT/ClO4−) films were fabricated using an electrodeposition method and used as resistance sensors of gaseous nitrogen dioxide. The experimental results indicate...
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Optical investigations of electrochemical processes using a long-period fiber grating functionalized by indium tin oxide
Publicationhe growing needs for fast and reliable sensing devices stimulate development of new technological solutions. In this work a new multi-domain sensing method is demonstrated where optical sensing device has been applied to enhance amount of data received during electrochemical analysis. Thin, optically transparent, high-refractive-index, and electrically conductive indium tin oxide (ITO) film was deposited using magnetron sputtering...
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Effects of UV light irradiation on fluctuation enhanced gas sensing by carbon nanotube networks
PublicationThe exceptionally large active surface-to-volume ratio of carbon nanotubes makes it an appealing candidate for gas sensing applications. Here, we studied the DC and low-frequency noise characteristics of a randomly oriented network of carbon nanotubes under NO2 gas atmosphere at two different wavelengths of the UV light-emitting diodes. The UV irradiation allowed to sense lower concentrations of NO2 (at least 1 ppm) compared to...
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Amperometric sensing of chemical oxygen demand at glassy carbon and silicon electrodes modified with boron-doped diamond
Publication.A boron-doped diamond (BDD) sensor is proposed for effective detection of chemical oxygen demand (COD) by means of amperometric technique. Boron-doped diamond thin films, acting as active sensors, were deposited on both silicon wafer and glassy carbon (GC) substrates by microwave plasma assisted chemical vapour deposition. SEM micrographs showed that BDD–Si displays triangle-faceted crystallites ca. 0.5–3 μm in size, while BDD–GC...
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Impedimetric sensing of α-amino acids driven by micro-patterned 1,8-Diazafluoren-9-one into titania- boron- doped maze-like nanocarbons
PublicationThe development of impedimetric, non-faradaic label-free sensors for the detection of α-amino acids constitutes a trailblazing technology for the fast and inexpensive quantification of such biomarkers. Since α-amino acids, such as glycine and sarcosine, are basic constituents in biological processes, a variation in their concentration may be an indicator of cardiovascular diseases and metabolic disorders or neurological conditions....
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Functionalized azobenzocrown ethers as sensor materials—The synthesis and ion binding properties
PublicationNew 13- and 16-membered azobenzocrown ethers with aromatic amino, amide, ether–ester or ether–amide residue in para position to an azo moiety were obtained. Acid–base properties and ion binding ability of the colored compounds were studied by spectroscopic methods: UV–vis, fluorimetry and 1H NMR spectroscopy. Selected azobenzocrowns were tested as ionophores in ion-selective membrane electrodes (ISEs) – classic and miniature all...
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Measurement of sub-nanometer molecular layers with ISFET without a reference electrode dependency
PublicationA new method of detection and measurement with sub-nanometer resolution of layers adsorbed or bonded to the ISFET's gate dielectric was presented. The sensitivity of this method is high enough to detect even partial mono-layer covering. The transconductance measurement of the ISFET provides independence of the output signal from pH changes and the driving electrode electrochemical potential instabilities. The stable reference electrode...
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Prototype of electrochemical sensor for measurements of volatile organic compounds in gases
PublicationThe paper presents a laboratory prototype of an electrochemical sensor for measurements of volatile organic compounds (VOCs) in gases, utilizing ionic liquids and commercial screen printed electrodes by DropSens. The following ionic liquids have been tested as the electrolyte and redox reaction environment: 1-butyl, 3-methylimidazolium dicyanoamide ([BMIM][N(CN)2]), 1-octyl, 3-methylimidazolium tetrafluoroborate ([OMIM][BF4]),...
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Metrological parameters of sulphur dioxide amperometric sensor containing addition of aprotic solvents
PublicationW publikacji zaprezentowano wyniki badań nad dodatku rozpuszczalnika aprotycznego do roztworu elektrolitu wewnętrznego czujnika na parametry metrologiczne prototypowego czujnika ditlenku siarki z membraną nafionową. Porównywano właściwości pięciu czujników różniących się składem elektrolitu. W każdym przypadku elektroda pracująca wykonana była ze złota, próżniowo napylonego na powierzchnię membrany. Roztwory elektrolitów zawierały...
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Fluctuation-enhanced scent sensing using a single gas sensor
PublicationWykrywanie zapachów podczas aromaterapii może być przeprowadzone za pomocą pojedynczego sensora gazów. W pracy rozważono efektywność detekcji zapachów olejków eterycznych za pomocą rezystancji DC oraz zjawisk fluktuacyjnych w tych sensorach, typu TGS2600,TGS2602,TGS823. Badania koncentrowały się na praktycznym zastosowaniu w aromaterapii do określania intensywności emitowanego zapachu. Opisano szczegółowo system do emisji zapachów.
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Multi-sensor monitoring of the corrosion rate and the assessment of the efficiency of a corrosion inhibitor in utility water installations
PublicationThis paper presents an implementation of the monitoring of the corrosion rate and the assessment of the efficiency of a corrosion inhibitor in a utility water installation using an automated corrosion monitoring system. Due to the fact that the corrosion inhibitor was added to water intended for human consumption, it was necessary to build a multi-sensor monitoring system. In order to implement corrosion monitoring using a linear...
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A method to monitor urinary carbon dioxide in patients with septic shock
PublicationSevere sepsis and septic shock are life-threatening conditions with mortality rates exceeding 31% (Levy et al., 2012) [1]. Septicemia was the most expensive US hospital condition in 2011 (Torio and Andrews, 2006)[2]. Urinary carbon dioxide may provide rapid, clinically useful information about a patient’s status, empowering physicians to intervene earlier and improve septic shock mortality. The objective of this paper is to validate...
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Laser patterned platform with PEDOT–graphene composite film for NO2 sensing
PublicationThis work presents a simple and fully electrochemical route used for fabricating of a NO2 gas sensor made of reduced-graphene-oxide-poly(3,4-ethylenedioxythiophene) composite film. The sensing platform was fabricated from alumina substrate and equipped with gold interdigitated electrodes and built-in heater.The temperature distribution on the surface of interdigitated electrodes was investigated by a thermalimaging camera and compared...
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Synthesis and application of tetrazole di and triamide derivatives in ion-selective membrane electrodes
PublicationA number of tetrazole diamides and triamides have been synthesized and applied as ion carries in ion-selective membrane electrodes. Their selectivity and sensitivity were studied towards alkali, alkaline earth, transition and heavy metal cations. it was found that membranes doped with 3 and 2-nitrophenyl octyl ether exhibit an almost theoretial Nernstian response for NH+ over relatively wide concentration range. Elestrodes with...
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Luminescence recognition material as an INHIBIT logic gate in presence of Pb2+ and Cu2+ ions in aqueous solutions
PublicationA recognition material consisting of silica xerogel with amino-modified surface selectively recognizes Pb2+ and Cu2+ (but only in presence of Pb2+ ions) in aqueous solutions of other metal ions. The analytical action of the material is based on a significant change in luminescence emission spectra of the material after chemisorption of Pb2+ ions. In the presence of Pb2+ in octahedral coordination environment, a new broad and strong...
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Solid-contact lead(II) ion-selective electrodes for potentiometric determination of lead(II) in presence of high concentrations of Na(I), Cu(II), Cd(II), Zn(II), Ca(II) and Mg(II)
PublicationLead and its compounds are a serious threat to the environment. Monitoring of this toxic heavy metal is a driving force for the continuous development of novel lead(II) ionophores to be applied in ion-selective electrodes. In this work a highly selective lead(II) ionophore, namely 25,26,27,28-tetrakis(piperidinylthiocarbonylmethylene)-p-tert-butylcalix[4]arene, was used in solid-contact ion-selective electrodes for determination...
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Gold-modified paper as microfluidic substrates with reduced biofouling in potentiometric ion sensing
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Multi-sensor monitoring of the corrosion rate and the assessment of the efficiency of a corrosion inhibitor in utility water installations
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Assessment of water quality based on multiparameter fiber optic probe
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Efficient reagent immobilization procedure for ion-sensitive optomembranes
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Application of optical fibres in oxidation-reduction titrations
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Novel usage of perinone polymer as solid contact in ion-selective electrodes
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Amperometric sensing of chemical oxygen demand at glassy carbon and silicon electrodes modified with boron-doped diamond
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Ordering of bacteriophages in the electric field: Application for bacteria detection
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Comparison of classical and fluctuation-enhanced gas sensing with PdxWO3 nanoparticle films
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TeSen – tool for determining thermometric parameters in ratiometric optical thermometry
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Influence of aprotic solvent on a signal of an amperometric sensor with Nafion membrane
PublicationW pracy przedstawiono wyniki badań charakterystyk analitycznych amperometrycznego czujnika ditlenku siarki wyposażonego w mebranę nafionową i wypełnionego roztworami elektrolitów o różnej zawartości dimetylosulfotlenku. Ocenie poddany został wpływ zawartości DMSO w roztworze elektrolitu wewnętrznego czujnika oraz prędkości przepływu gazu na czułość czujnika i czas odpowiedzi na zmiany stężenia ditlenku siarki.