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Vägkorsningar har ofta visat sig vara hotspots för höga luftföroreningshalter på grund av ökad acceleration och inbromsning i samband med korsningen samt på grund av den ökade trafiken där flera vägar möts. Det finns få luftkvalitetsmätningar utförda i korsningar eftersom dessa miljöer är svårtolkade och sällan representativa. Mer kunskap behövs om korsningars påverkan på luftföroreningar exempelvis för att kunna utforma korsningar för att minska exponeringen för gående och cyklister. En möjlighet vore att införa ett korsningstillägg i emissions- eller luftkvalitetsmodeller för att kunna ta hänsyn till detta. För att öka kunskapen kring partikelhalter i korsningar har två mätkampanjer utförts i anslutning till korsningen Hornsgatan–Ringvägen i Stockholm. Under den första mätkampanjen mättes partikelhalter på två punkter: i korsningen och cirka 90 meter in på länken. Resultaten visade att det i genomsnitt var högre halter på länken än i korsningen och att halternas inbördes variation till största delen var beroende av vinden. Under den andra mätkampanjen mättes partikelhalter med 12 mikrosensorer placerade längs med Hornsgatan för att undersöka hur halterna varierade på olika avstånd från korsningen. Inga tydliga skillnader mellan halterna på olika avstånd från korsningen kunde dock ses, vilket kan tyda på att mikrosensorerna inte kunde registrera de trafikinducerade partiklarna med önskvärd noggrannhet. Högre halter kunde dock ibland registreras på den södra sidan av vägen, där fordonen bromsar inför korsningen och det är svagt nedåtlut, vilket kan tyda på att halterna påverkas av en ökad mängd bromspartiklar eller på grund av något vindmönster., Intersections are often considered hotspots of air pollution due to the increased acceleration and braking and due to the increased traffic where two ore several roads cross. There are few air quality measurements in intersections because these environments are complicated and seldom representative. More knowledge on how intersections affect air pollution is needed, for example to understand the optimal design to decrease the exposure to air pollution for pedestrians or cyclists. There is also a possibility to introduce add an extra “intersection-constant” in emission or air quality models to take the possible increase into account. To improve the knowledge on particle concentrations in intersections, two measurement campaigns have been performed in the intersection between Hornsgatan and Ringvägen in Stockholm. During the first measurement campaign, particle concentration was measured in two locations: in the intersection and in a street canyon at around 90 m distance from it. The results showed that the average concentration was higher in the street canyon than in the intersection and that the main cause of the concentration differences was explained by the wind. During the second campaign, the particle concentration was measured with 12 micro-sensors placed along the street canyon to investigate how the concentration varied with distance from the intersection. However, no clear differences between sensors at different distances was observed. This could be due to a lack of sensitivity in the sensors to traffic-related particles. Nevertheless, some differences could be seen between the two sides of the street canyon, often with higher values on the south side where the vehicles were reducing their speed to enter the intersection and where there is a slight downwards slope. The increase could be due to an increased amount of brake wear emissions or due to some wind pattern, Korsningar och deras påverkan på partikelemissioner/Traffic intersections and their effect on particle emissions

Raw data for Method development of application for microsensors in (bio)electrochemical systems to measure pH, H2 and ORP in 3D graphite cathodes

The operating principle of Pirani pressure sensors is based on the pressure dependence of a suspended strip's electrical conductivity, caused by the thermal conductance of the surrounding gas which changes the Joule heating of the strip. To realize such sensors, not only materials with high temperature dependent electrical conductivity are required, but also minimization of the suspended strip dimensions is essential to maximize the responsivity and minimize the power consumption. Due to this, nanomaterials are especially attractive for this application. Here, we demonstrate the use of a multi-layer suspended graphene strip as a Pirani pressure sensor and compare its behavior with existing models. A clear pressure dependence of the strip's electrical resistance is observed, with a maximum relative change of 2.75% between 1 and 1000 mbar and a power consumption of 8.5 mW. The use of graphene enables miniaturization of the device footprint by 100 times compared to state-of-the-art. Moreover, miniaturization allows for lower power consumption and/or higher responsivity and the sensor's nanogap enables operation near atmospheric pressure that can be used in applications such as barometers for altitude measurement. Furthermore, we demonstrate that the sensor response depends on the type of gas molecules, which opens up the way to selective gas sensing applications. Finally, the graphene synthesis technology is compatible with wafer-scale fabrication, potentially enabling future chip-level integration with readout electronics., Electronic Components, Technology and Materials, Photovoltaic Materials and Devices, QN/van der Zant Lab, Dynamics of Micro and Nano Systems, QN/Steeneken Lab

In this work, we report on the development of a catheter-based sensor designed for measuring the concentration of histamine in the human duodenum. Certain gut disorders, such as the irritable bowel syndrome (IBS), are associated with elevated levels of intestinal histamine due to chronic immune activation. As it is still impossible to determine histamine concentrations in vivo, a nasointestinal catheter with histamine-sensing capabilities has the potential to become a valuable diagnostic instrument. Regarding the sensing principle, we selected impedance spectroscopy using voltages that are compatible with intra-body applications with molecularly imprinted polymers (MIPs) as recognition elements. MIPs are synthetic receptors that offer the advantages of robustness, high specificity and selectivity for histamine as a target. In this specific case, the MIPs were synthesized from acryclic acid monomers, which guarantees a uniform binding capacity within the pH range of intestinal fluid. We have validated the catheter sensor on human intestinal liquids spiked with histamine in a testing setup that mimics the environment inside the duodenum. The dose-response curves show an analytical range between 5 and 200 nM of histamine, corresponding to physiologically normal conditions while higher concentrations correlate with disease. The key output signal of the sensor is the resistive component of the MIP-functionalized titanium electrodes as derived from the equivalent-circuit modelling of full-range impedance spectra. Future applications could be catheters tailored to cardiovascular, urological, gastrointestinal, and neurovascular applications. This, in combination with the versatility of the MIPs, will make this sensor platform a versatile diagnostic tool.

This study aimed to develop a wearable sensor system, using machine‐learning models, capable of accurately estimating peak ground reaction force (GRF) during ballet jumps in the field. Female dancers (n = 30) performed a series of bilateral and unilateral ballet jumps. Dancers wore six ActiGraph Link wearable sensors (100 Hz). Data were collected simultaneously from two AMTI force platforms and synchronised with the ActiGraph data. Due to sensor hardware malfunctions and synchronisation issues, a multistage approach to model development, using a reduced data set, was taken. Using data from the 14 dancers with complete multi‐sensor synchronised data, the best single sensor was determined. Subsequently, the best single sensor model was refined and validated using all available data for that sensor (23 dancers). Root mean square error (RMSE) in body weight (BW) and correlation coefficients (r) were used to assess the GRF profile, and Bland–Altman plots were used to assess model peak GRF accuracy. The model based on sacrum data was the most accurate single sensor model (unilateral landings: RMSE = 0.24 BW, r = 0.95; bilateral landings: RMSE = 0.21 BW, r = 0.98) with the refined model still showing good accuracy (unilateral: RMSE = 0.42 BW, r = 0.80; bilateral: RMSE = 0.39 BW, r = 0.92). Machine‐learning models applied to wearable sensor data can provide a field‐based system for GRF estimation during ballet jumps.

In this work, we propose an interferometric humidity sensor based on a polymer micro-cap bonded off-center on the polished end of a standard single mode fiber (SMF). In our sensor, the sensitive part is the micro-cap. In the interferometer fabrication process, we can adjust the misalignment between the core and the micro-cap. It allowed us to control the visibility of the interference pattern. In our device, water molecules absorbed by the polymer microcap causes changes in the height of the microcap. This results in measurable shifts of the interference pattern. The fabricated samples were tested in a calibrated climatic chamber in the range from (similar to)10 to (similar to)95% of relative humidity (RH). The sensitivity and resolution of our device was found to be 148 pm per %RH and 0.04% RH, respectively. The obtained results suggest that our sensors can be useful to monitor relative humidity (RH) in miniature spaces.

We address noise and stability of adsorptionbased sensing of ternary gas mixtures in affinity-based MEMS, NEMS and NOEMS sensors. We investigate mechanisms of such chemical sensing in diverse industrial environments where ternary gas mixtures are of importance. In all existing sensing devices signal fluctuations determine their ultimate performance, and in affinity-based nanodevices the prevailing noise is caused by adsorption and desorption of different species at the sensor surface. We consider analytically and numerically detection of three-component gas mixtures. We present results obtained by applying the conventional method for assessing stability of chemical reactions to three component monolayer adsorption. Gas molecules modeling as spherical particles is suitable for applying any model regarding population dynamics, but taking molecular dimension and orientation into account is more realistic. Noise analysis in time and frequency domain is performed for two different classes of ultrahigh sensitivity adsorption based gas sensors: (nano) plasmonic sensors (refractometric devices) and MEMS/NEMS resonator-based devices.

We demonstrate a portable multisensor fusion system for the automated analysis of multiple beverages. The system makes use of compact and low-power-consumption electronic equipment to simultaneously read out an array of microsensors formed by six ion-selective field-effect transistors (ISFETs), one conductivity sensor, one redox potential sensor, and two amperometric microelectrodes. A custom Python application running on a laptop computer receives real-time multivariate data via USB, and provides chemometric models to classify different varieties and to quantify relevant parameters of mineral water and wine. The software also includes a graphical user interface (GUI) to visualize readouts and analytical estimates.

We report on microscopic polymer spherical caps bonded onto the cleaved end of a single-mode fiber (SMF) for fast, accurate, and sensitive temperature sensing. The microcaps were fabricated by dispensing sub nano-liter amounts of UV-curable polymer onto the end face of a standard SMF that was cleaved at a small angle. A reflection from the SMF-polymer interface combined with a reflection from the polymer-external medium interface gives rise to a well-defined interference pattern. The high thermal expansion coefficient of the polymer used to build the micro-caps allowed us to achieve temperature sensitivity up to 270 pm/°C, resolution of 0.04 °C, and thermal response time of around 2.5 s. The simple fabrication process and the broad operating wavelength (from 800 to 1600 nm, approximately) of our devices along with the diversity of polymers currently available, make the concept and approach proposed here appealing for diverse sensing applications.

Bottom hypoxia and consequential hydrogen sulfide (H2S) release from sediment in eutrophic estuaries is a major global environmental issue. We investigated dissolved oxygen, pH and H2S concentration profiles with microsensors and by sectioning sediment 2 cores followed by colorimetric analysis. The results of these analyses were then compared with the physicochemical properties of the bottom water and sediment samples to determine their relationships with H2S production in sediment. High organic matter and fine particle composition of the sediment reduced the oxidation-reduction potential, stimulating H2S production. Use of a microsensor enabled measurement of H2S concentration profiles with submillimeter resolution, whereas the conventional sediment-sectioning method gave H2S measurements with a spatial resolution of 10 mm. Furthermore, microsensor measurements revealed H2S consumption occurring at the sediment surface in both the microbial mat and the sediment anoxic layer that were not observed with sectioning. This H2S consumption prevented H2S release into the overlying water. However, the microsensor measurements had the potential to underestimate H2S concentrations. We propose that a combination of several techniques to measure microbial activity and determine its relationships with physicochemical properties of the sediment is essential to understanding the sulfur cycle under hypoxic conditions in eutrophic sediments.

The purpose of this thesis has been to learn and describe the main concepts about gas sensors based on metal oxides, in order to apply them to real life problems by performing experiments in the framework of an international project. This thesis is divided in two blocks: first, a theoretical part, which offers a review of the working principles of gas sensors based on metal oxides (one of the most used technologies for gas sensing), their historical development and current state of the art. The second part describes the practical work carried out in the framework of a joint project by the Slovak Technical Support, the Technical University of Ilmenau and commercial companies such as LOX Technologies, in which a new type of gas sensor is being developed., Trabajo de final de grado realizado durante una estancia de movilidad en la Universitad Técnica de Eslováquia (STU-FEI), trabajando en el departamento de sensores del instituto de fotónica (UEF). El trabajo està bien dividido en una parte teórica, necesaria para la posterior parte práctica, gracias a la qual he aprendido toda una serie de conceptos sobre los sensores de gas basados en óxidos metálicos, una de las tecnologías más utilizadas para medir gases. El trabajo práctico ha consistido en ciertos experimentos donde se ha analitzado la respuesta de un nuevo tipo de sensor al estar bajo la influencia de diferentes gases, así como la dependencia de la resistencia de los sensores en función de la distancia, entre otros. Este trabajo se ha desarrollado en el marco de un proyecto de cooperación europeo entre la STU, la Universitad Técnica de Ilmenau (TUI) y compañías comerciales como LOX Technologies., Treball de final de grau realitzat durant una estada de mobilitat a la Universitat Tècnica de Eslovàquia (STU-FEI), treballant al departament de sensors de l'institut de fotònica (UEF). El treball està ben dividit en una part teòrica, necessària per a la posterior part pràctica, i gràcies a la qual he aprés tota una serie de conceptes sobre els sensors de gas basats en òxids metàl·lics, una de les tecnologies més utilitzades al mesurar gasos, a més de resumir la seva evolució històrica i la situació en que es troba el sector. El treball pràctic ha consistit en certs experiments on s'ha analitzat la resposta d'un nou tipus de sensor al estar sota l'influència de diferents gasos, així com la dependencia de la resistència dels sensors en funció de la distancia, entre altres. La part pràctica s'ha realitzat en el marc d'un projecte de cooperació europeu entre la STU, l'Universitat Tècnica de Ilmenau (TUI) i companyies comercials com ara LOX Technologies.

To target a wide range of high-temperature applications [1-4], the Ångström Space Technology Centre has added High-Temperature Co-fired Ceramics, HTTC, technology to its repertoire. Usually, this technology follows a processing scheme where thin sheets of green-body ceramics are metallized through screen printing and structured by embossing, punching or milling, before they are laminated and sintered to form components. A limitation with this, is the difficulty of realizing freely suspended metal structures, which is a disadvantage in, e.g., the fabrication of calorimetric sensors or electric field probes. In this work, the embedding of platinum wires in HTCC is explored experimentally, and demonstrated for use in pressure and plasma I-V sensing.

The 1st EuNetAir Air Quality Joint Intercomparison Exercise organized in Aveiro (Portugal) from 13th–27th October 2014, focused on the evaluation and assessment of environmental gas, particulate matter (PM) and meteorological microsensors, versus standard air quality reference methods through an experimental urban air quality monitoring campaign. The IDAD-Institute of Environment and Development Air Quality Mobile Laboratory was placed at an urban traffic location in the city centre of Aveiro to conduct continuous measurements with standard equipment and reference analysers for CO, NOx, O3, SO2, PM10, PM2.5, temperature, humidity, wind speed and direction, solar radiation and precipitation. The comparison of the sensor data generated by different microsensor-systems installed side-by-side with reference analysers, contributes to the assessment of the performance and the accuracy of microsensor-systems in a real-world context, and supports their calibration and further development. The overall performance of the sensors in terms of their statistical metrics and measurement profile indicates significant differences in the results depending on the platform and on the sensors considered. In terms of pollutants, some promising results were observed for O3 (r2: 0.12–0.77), CO (r2: 0.53–0.87), and NO2 (r2: 0.02–0.89). For PM (r2: 0.07–0.36) and SO2 (r2: 0.09–0.20) the results show a poor performance with low correlation coefficients between the reference and microsensor measurements. These field observations under specific environmental conditions suggest that the relevant microsensor platforms, if supported by the proper post processing and data modelling tools, have enormous potential for new strategies in air quality control.

Micro-optical sensors based on optical waveguides are widely used to measure temperature, force and strain but also to detect biological and chemical substances such as explosives or toxins. While optical micro-sensors based on silicon technology require complex and expensive process technologies, a new generation of sensors based completely on polymers offer advantages especially in terms of low-cost and fast production techniques. We have developed a process to integrate micro-optical components such as embedded waveguides and optical interconnects into polymer foils with a thickness well below one millimeter. To enable high throughput production, we employ hot embossing technology, which is capable of reel-to-reel fabrication with a surface roughness in the optical range. For the waveguide fabrication, we used the thermoplastic polymethylmethacrylate (PMMA) as cladding and several optical adhesives as core materials. The waveguides are characterized with respect to refractive indices and propagation losses. We achieved propagation losses are as low as 0.3 dB/cm. Furthermore, we demonstrate coupling structures and their fabrication especially suited to integrate various light sources such as vertical-cavity surface-emitting lasers (VCSEL) and organic light emitting diodes (OLED) into thin polymer foils. Also, we present a concept of an all-polymer and waveguide based deformation sensor based on intensity modulation, which can be fabricated by utilizing our process. For future application, we aim at a low-cost and high-throughput reel-to-reel production process enabling the fabrication of large sensor arrays or disposable single-use sensing structures, which will open optical sensing to a large variety of application fields ranging from medical diagnosis to automotive sensing. © 2016 SPIE.

The 1st EuNetAir Air Quality Joint Intercomparison Exercise organized in Aveiro (Portugal) from 13th–27th October 2014, focused on the evaluation and assessment of environmental gas, particulate matter (PM) and meteorological microsensors, versus standard air quality reference methods through an experimental urban air quality monitoring campaign. The IDAD-Institute of Environment and Development Air Quality Mobile Laboratory was placed at an urban traffic location in the city centre of Aveiro to conduct continuous measurements with standard equipment and reference analysers for CO, NOx, O3, SO2, PM10, PM2.5, temperature, humidity, wind speed and direction, solar radiation and precipitation. The comparison of the sensor data generated by different microsensor-systems installed side-by-side with reference analysers, contributes to the assessment of the performance and the accuracy of microsensor-systems in a real-world context, and supports their calibration and further development. The overall performance of the sensors in terms of their statistical metrics and measurement profile indicates significant differences in the results depending on the platform and on the sensors considered. In terms of pollutants, some promising results were observed for O3 (r2: 0.12–0.77), CO (r2: 0.53–0.87), and NO2 (r2: 0.02–0.89). For PM (r2: 0.07–0.36) and SO2 (r2: 0.09–0.20) the results show a poor performance with low correlation coefficients between the reference and microsensor measurements. These field observations under specific environmental conditions suggest that the relevant microsensor platforms, if supported by the proper post processing and data modelling tools, have enormous potential for new strategies in air quality control. © 2016 Elsevier Ltd

This paper reports the permanent frequency mismatch reduction of the primary wineglass modes in a planar axisymmetric resonator by strategic mass loading. The resonator consists of a set of concentric rings that are affixed to neighboring rings by a staggered system of spokes. The outer layers of spokes are targets for mass deposition. This paper develops modified ring equations that guide the mass perturbation process, and despite the fact that the deposited mass and deposition locations are quantized, it is possible to systematically reduce the frequency difference of the wineglass modes to effective degeneracy such that two modes cannot be distinguished in a frequency response plot. Results on five resonators are reported with nominal wineglass modes near 14 kHz, quality factors of 50k, and frequency mismatches exceeding 30 Hz in some cases, but with postperturbation mismatches smaller than 80 mHz. Furthermore, it is also shown that the quality factors remain unchanged. [2014-0227]

Advances in microsensors, microprocessors and microdisplays are creating new opportunities for improving vision in degraded environments through the use of head-mounted displays. Initially, the cutting-edge technology used in these new displays will be expensive. Inevitably the cost of providing the additional sensor and processing required to support binocularity brings the value of binocularity into question. The value of binocularity in human vision is well documented, yet the value of binocularity in sensor/display systems for aided vision is controversial. Several assessments comparing binocular, biocular and monocular head-mounted displays for aided vision have concluded that the additional performance, if any, provided by binocular head-mounted displays does not justify the cost. It is possible that the human binocularity advantage doesn?t carry over to the aided vision application, but more likely the experimental approaches used in the past have been too coarse to measure its subtle but important benefits. Evaluating the value of binocularity in aided vision applications requires an understanding of the characteristics of both human vision and head-mounted displays. With this understanding, the value of binocularity in aided vision can be estimated and experimental evidence can be collected to confirm or reject the presumed binocular advantage, enabling improved decisions in aided vision system design. This paper describes four models; stereopsis, modulation transfer function area for stereopsis, probability summation and binocular summation, that may be useful in assessing the advantage of binocularity in aided vision.

Knowledge of bacterial activity inside biofilms is key to the optimization of applied biotechnologies. A novel dissolved oxygen microelectrode array (DO-MEA) sensor has been designed and fabricated on a needle using microelectromechanical systems technology, in order to provide a multipoint, simultaneous dissolved oxygen snapshot profile inside a biofilm. The sensor consisted of eleven gold disk electrodes with integrated counter (CE) and pseudo-reference (RE) electrodes. Three different sensor designs are fabricated, and their responses are fully characterized and evaluated under different environmental conditions. The developed sensor is validated against a commercial Clark-type microelectrode overcoming its drawbacks, by profiling a heterotrophic biofilm cultivated in a flat-plate bioreactor. The DO-MEA sensor will be improved with the protection of the electrodes and will be fabricated on a thinner substrate, for becoming a powerful tool for the research of many similar biological-based processes and applications., Peer Reviewed, Pòster

This paper presents analysis of the noise spectra of closed-loop mode-matched vibratory gyros. Closed-form expressions for the noise-equivalent angular rate spectrum as well as the integrated angular rate (angle) variance are derived to explore the effects of modal frequency mismatch, closed-loop bandwidth, and the spectra of noise sources appearing at the sensor's input and output. It is shown that noise sources located at the output of the sensor's electromechanical transfer function create angle white noise in the closed-loop sensor. The angle white noise dominates the integrated rate behavior until it crosses the angle random walk asymptote at integration times exceeding the sensor's open-loop time constant. Even though the closed-loop sensor asymptotically recovers the angle random walk figure associated with the mode-matched open-loop sensor, the results can be used to quantify the larger integrated rate variance that is produced as a consequence of extending the sensor's bandwidth through feedback. A parameter, called the effective bandwidth, is introduced to capture the relative importance of the input noise versus output noise in determining the noise-equivalent rate spectrum. It is shown that the rate noise spectrum is robust to frequency mismatch as long as it does not exceed the effective bandwidth parameter. Empirical data obtained with a high performance MEMS vibratory gyro shows excellent agreement with the model predictions for a variety of sensor configurations including frequency-matched, frequency-mismatched, modified bandwidth, and manipulated input noise intensity cases. © 2013 IEEE.

An analytical model of the thermal flow sensor has been developed. The results of analytical model application are utilized to develop a thermal flow microsensor with optimal functional characteristics. The technology to manufacture the microsensor is described. A prototype of the microsensor suitable to be used in the mass air flow meter has been designed. The basic characteristics of the microsensor are presented. © 2013 Elsevier Ltd.

This paper presents an energy-efficient readout circuit for resonant sensors that operates based on a transient measurement method. The resonant sensor is driven at a frequency close to its resonance frequency by an excitation source that can be intermittently disconnected, causing the sensor to oscillate at its resonance frequency with exponentially decaying amplitude. By counting the zero crossings of this ring-down response, the interface circuit can detect the resonance frequency. In contrast with oscillator-based readout, the presented readout circuit is readily able to detect quality factor (Q) of the resonator from the envelope of the ring-down response, and can be used even in the presence of large parasitic capacitors. A prototype of the readout circuit has been integrated in 0.35 ?m CMOS technology, and consumes only 36 ?A from a 3.3 V supply during a measurement time of 2 ms. The resonance frequency and quality factor of a micro-machined SiN resonator obtained using this prototype are in good agreement with results obtained using impedance analysis. Furthermore, a clear transient response is observed to ethanol flow using the presented readout, demonstrating the use of this technique in sensing applications., Microelectronics, Electrical Engineering, Mathematics and Computer Science

Microscale strain gauges are widely used in micro electro-mechanical systems (MEMS) to measure strains such as those induced by force, acceleration, pressure or sound. We propose all-optical strain sensors based on micro-ring resonators to be integrated with MEMS. We characterized the strain-induced shift of the resonances of such devices. Depending on the width of the waveguide and the orientation of the silicon crystal, the linear wavelength shift per applied strain varies between 0.5 and 0.75 pm/microstrain for infrared light around 1550 nm wavelength. The influence of the increasing ring circumference is about three times larger than the influence of the change in waveguide effective index, and the two effects oppose each other. The strong dispersion in 220 nm high silicon sub-wavelength waveguides accounts for a decrease in sensitivity of a factor 2.2 to 1.4 for waveguide widths of 310 nm to 860 nm. These figures and insights are necessary for the design of strain sensors based on silicon waveguides., ImPhys/Imaging Physics, Applied Sciences

If driven sufficiently strongly, superconducting microresonators exhibit nonlinear behavior including response bifurcation. This behavior can arise from a variety of physical mechanisms including heating effects, grain boundaries or weak links, vortex penetration, or through the intrinsic nonlinearity of the kinetic inductance. Although microresonators used for photon detection are usually driven fairly hard in order to optimize their sensitivity, most experiments to date have not explored detector performance beyond the onset of bifurcation. Here, we present measurements of a lumped-element superconducting microresonator designed for use as a far-infrared detector and operated deep into the nonlinear regime. The 1?GHz resonator was fabricated from a 22?nm thick titanium nitride film with a critical temperature of 2?K and a normal-state resistivity of 100????cm. We measured the response of the device when illuminated with 6.4 pW optical loading using microwave readout powers that ranged from the low-power, linear regime to 18 dB beyond the onset of bifurcation. Over this entire range, the nonlinear behavior is well described by a nonlinear kinetic inductance. The best noise-equivalent power of 2×10?16?W/Hz1/2 at 10 Hz was measured at the highest readout power, and represents a ?10 fold improvement compared with operating below the onset of bifurcation., Microelectronics, Electrical Engineering, Mathematics and Computer Science

Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern since N2O is a major stratospheric ozone-depleting substance and an important greenhouse gas. The emission of N2O from a lab-scale granular sequencing batch reactor (SBR) for partial nitrification (PN) treating synthetic wastewater without organic carbon was therefore determined in this study, because PN process is known to produce more N2O than conventional nitrification processes. The average N2O emission rate from the SBR was 0.32 ± 0.17 mg-N L−1 h−1, corresponding to the average emission of N2O of 0.8 ± 0.4% of the incoming nitrogen load (1.5 ± 0.8% of the converted NH4+). Analysis of dynamic concentration profiles during one cycle of the SBR operation demonstrated that N2O concentration in off-gas was the highest just after starting aeration whereas N2O concentration in effluent was gradually increased in the initial 40 min of the aeration period and was decreased thereafter. Isotopomer analysis was conducted to identify the main N2O production pathway in the reactor during one cycle. The hydroxylamine (NH2OH) oxidation pathway accounted for 65% of the total N2O production in the initial phase during one cycle, whereas contribution of the NO2− reduction pathway to N2O production was comparable with that of the NH2OH oxidation pathway in the latter phase. In addition, spatial distributions of bacteria and their activities in single microbial granules taken from the reactor were determined with microsensors and by in situ hybridization. Partial nitrification occurred mainly in the oxic surface layer of the granules and ammonia-oxidizing bacteria were abundant in this layer. N2O production was also found mainly in the oxic surface layer. Based on these results, although N2O was produced mainly via NH2OH oxidation pathway in the autotrophic partial nitrification reactor, N2O production mechanisms were complex and could involve multiple N2O production pathways.

The broad goal of this project is to develop new computational processes for leveraging visual cues for image-based scene understanding, and we seek to achieve this goal through a careful analysis of reflectance, light transport, and imaging. During the past year, we have continued our exploration of micro computer vision systems, meaning those that can accomplish useful visual tasks within the power and size constraints of micro-scale platforms like micro air vehicles and micro sensor nodes. We have also developed a passive method for simultaneous depth and color imaging that exploits a new statistical model of joint spatial and spectral structure in natural images.

This study demonstrated the use of a unique prototype gas chromatograph with sensor array detection, the analytical components of which are microfabricated from Si (micro-GC), for analysis of indoor air concentrations of trichloroethylene (TCE) at low- and sub ppb levels, related to vapor intrusion (VI) applications. The objectives of this study were to demonstrate the performance of the prototype micro-GC in two operating modes: portable mode for forensic and spatial monitoring; and fixed location mode for longer term temporal monitoring (exposure estimation). Results from the micro GC and from TO -15 reference samples were compared. Above the mitigation action level (MAL; 2.3 ppb), the micro-GC accurately determined TCE under complex field matrix conditions. Below the MAL, TCE micro GC determinations were positively biased due to unresolved interferences. This study stands as the first of its kind, where micro-GC instrumentation was shown capable of sustained, reliable, automated measurements of a trace-level component (TCE) in a complex VOC mixture in real-world environments., Prepared in cooperation with the School of Public Health, University of Michigan, Ann Arbor, Ml. Engineering Research Centers Program of the National Science Foundation under Award Number ERC-9986866 (University of Michigan s Center for Wireless Integrated MicroSystems) also supported this project. The micro-fabricated devices described in this report were made at University of Michigan's Lurie Nanofabrication Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation. The original document contains color images.

Presented at the 2nd Multifunctional Materials for Defense Workshop in conjunction with the 2012 Annual Grantees'/Contractors' Meeting for AFOSR Program on Mechanics of Multifunctional Materials & Microsystems Held 30 July - 3 August 2012 in Arlington, VA. Sponsored by AFRL, AFOSR, ARO, NRL, ONR, and ARL. U.S. Government or Federal Rights License

This paper describes the design, fabrication, sim- ulation, and experimental results of an improved miniaturized two-axis sun sensor for industrial applications, created by adapt- ing a technology used previously in satellite applications. The sensor for each axis is composed of six photodiodes integrated in a crystalline-silicon substrate and a layer of cover glass, which is used to protect the silicon and to hold the windows. The high precision is obtained by the subdivision of the field of view, which is ± 60 ◦ , with a resolution of 0.1 ◦ . Each region is controlled by an independent high-precision solar sensor. The sensor can be used for sun-tracking applications in a photovoltaic system, heliostat concentration plants, and lighting applications.

Bakalářské práce pojednává o principech mikroelektromechanických systémů (MEMS) a jejich využitelností. Teoretická část objasňuje principy a výrobní technologie MEMS systémů. Dále je zde rozebráno jejich obecné použití. Praktická část práce se zabývá využitím systémů v průmyslu komerční bezpečnosti, kde všude lze tyto systémy nalézt a další možné aplikace, které mohou sloužit pro bezpečnostní průmysl. Závěrečná část práce obsahuje výsledky praktického měření s konkrétním čidlem MEMS, a to akcelerometrem. Podrobně je rozebrán postup měření a provedeno vyhodnocení dosažených výsledků., The aim of this thesis is to explain the principles of microelectromechanical systems (MEMS) and indicate the applicability of these systems. The theoretical part explains the principles and manufacturing technology of MEMS systems. There is also stated their general use. The practical part deals with using of these systems in the commercial security industry and where can be all these systems found. There are stated other possible applications that can be used for the security industry too. The final part of this thesis contains results of practical measurement with MEMS sensor, an accelerometer. There is analyzed measurement procedure and evaluation of achieved results in detail., Ústav bezpečnostního inženýrství, obhájeno

In the underground rock characterization facility tunnel "ONKALO" in Finland massive biofilms were observed attached to the fractured bedrock at a depth of 70 m. Experiments were performed in the laboratory to study the effect on the behavior of uranium in biofilms by adding uranium to the fracture water with a final uranium concentration (4 x10-5 M) relevant for what can be expected from an injured and leaking waste canister in the far-field during a nuclear event in a HLW repository. The results obtained by analysis, microsensor measurements, TRLFS investigation, EF-TEM/EELS studies and thermodynamic calculations clearly indicate that biofilms have to be considered as microenvironments, which differ significantly from the surrounding medium. Inside the biofilm a pH of 5.37 was recorded, which is about 3.5 units lower than the pH of the surrounding fracture water. Similarly, the redox potential of +73 mV is approximately 420 mV lower than the redox potential measured in the fracture water. The addition of uranium results in an increase of the pH in the biofilm to 7.27 and a decrease of the redox potential to -164 mV mV. The changes of redox potential and pH are influencing the bioavailability of uranium since microbial metabolic processes are sensitive to metals and their speciation. EF-TEM investigations showed that in the biofilm uranium was immobilized intracellular in bacteria by a biologically mediated uranyl phosphate formation similar to needle-shaped Autunite (Ca[UO2]2[PO4]2•2-6H2O) or meta-Autunite (Ca[UO2]2[PO4]2•10-12H2O). In contrast, TRLFS studies of the contaminated fracture water showed aqueous uranium carbonate species, most likely Ca2UO2(CO3)3, which was formed using the available high amount of carbonate from the water. The results are in agreement with the thermodynamic calculation of the theoretical predominance field of uranium species, formed in the uranium contaminated fracture water at the measured geochemical parameters. Our studies clearly

Photosynthesis, respiration, N(2) fixation and ammonium release were studied directly in Nodularia spumigena during a bloom in the Baltic Sea using a combination of microsensors, stable isotope tracer experiments combined with nanoscale secondary ion mass spectrometry (nanoSIMS) and fluorometry. Cell-specific net C-and N(2)-fixation rates by N. spumigena were 81.6 +/- 6.7 and 11.4 +/- 0.9 fmol N per cell per h, respectively. During light, the net C: N fixation ratio was 8.0 +/- 0.8. During darkness, carbon fixation was not detectable, but N(2) fixation was 5.4 +/- 0.4 fmol N per cell per h. Net photosynthesis varied between 0.34 and 250 nmol O(2) h(-1) in colonies with diameters ranging between 0.13 and 5.0 mm, and it reached the theoretical upper limit set by diffusion of dissolved inorganic carbon to colonies (>1 mm). Dark respiration of the same colonies varied between 0.038 and 87 nmol O(2) h (1), and it reached the limit set by O(2) diffusion from the surrounding water to colonies (>1 mm). N(2) fixation associated with N. spumigena colonies (41mm) comprised on average 18% of the total N(2) fixation in the bulk water. Net NH(4)(+) release in colonies equaled 8-33% of the estimated gross N(2) fixation during photosynthesis. NH(4)(+) concentrations within light-exposed colonies, modeled from measured net NH(4)(+) release rates, were 60-fold higher than that of the bulk. Hence, N. spumigena colonies comprise highly productive microenvironments and an attractive NH(4)(+) microenvironment to be utilized by other (micro) organisms in the Baltic Sea where dissolved inorganic nitrogen is limiting growth., authorCount :7

Thermomechanical analysis (TMA) is widely used to characterize materials and determine transition temperatures and thermal expansion coefficients. Atomic-force microscopy (AFM) microcantilevers have been used for TMA. We have developed a micromachined probe that includes two embedded sensors: one for measuring the mechanical movement of the probe (deflection) and another for providing localized heating. The new probe reduces costs and complexity and allow for portability thereby eliminating the need for an AFM. The sensitivity of the deflection element ((?R/R)/deflection) is 0.1 ppm/nm and its gauge factor is 3.24. The melting temperature of naphthalene is measured near 78.5 ºC., Electrical Engineering, Mathematics and Computer Science

Microsensors were used in order to perform profiles of redox potential and pH within biofilms, which have formed in small drainage channels of uranium contaminated acidic mine drainage (AMD) waters from an underground uranium mine in Saxony (Germany). The results clearly showed significant differences between the redox potential and pH of the AMD water in comparison to the measured values in the biofilm, indicating that the biofilms have built up their own microenvironment. The redox potential of 921 ± 17 mV inside the biofilm was approximately 200 mV higher than in the surrounding water. The pH of the biofilm was characterized by a pH of 1.9 ± 0.1, whereas the pH of the AMD water showed a higher pH of 2.6 ± 0.1. The results were plotted into the pH-Eh diagram for the U-S-O-H-C system, which was constructed by using the analytical data of the drainage water for the calculation of the predominance fields of different uranium species. It clearly shows that an aqueous uranium(VI) sulfate complex exists in the biofilm as well as in the water under the ambient conditions. Laboratory experiments, simulating the first state of flooding of the uranium mine by increasing the pH of the AMD water, showed the influence of the Ferrovum myxofaciens dominated biofilms on the migration of uranium. Due to homeostatic mechanisms the microbes maintain their intracellular pH even when the pH of the water is increased. Consequently, an immobilization of uranium in the biofilms as well as in the AMD water is inhibited as long as Ferrovum myxofaciens will be the dominant bacteria of the biofilms.