Use of a Single Multiplexed CMOS Oscillator as Direct Frequency Read-Out for an Array of Eight AlN Contour-Mode NEMS Resonant Sensors

This paper reports on the first demonstration of a single multiplexed CMOS oscillator circuit employed as direct frequency readout for an array of 8 nanoscaled aluminum nitride Contour-Mode Resonant Sensors (CMR-S). In this first prototype 8 thin-film (250 nm) AlN CMR-S operating at 186 MHz were fabricated on the same chip and simultaneously wire-bonded to a Pierce-like oscillator circuit (fabricated in the ON Semiconductor 0.5 µm CMOS process) by means of 8 CMOS transmission gates addressed via a 3 bit on-chip decoder. The 8 CMR-S were simultaneously exposed to different concentrations of methanol (0.1–1% of the saturated vapor pressure) and their response was monitored in a time-multiplexed mode. Frequency shifts of 300 Hz corresponding to changes of mass per unit area of 7 ag/µm2 were experimentally detected. Values of phase noise derived Allan deviation as low as 0.9 Hz were measured. Such Allan deviation translates in an estimated limit of detection of 21 zg/µm2

ss-DNA Functionalized Ultra-Thin-Film AlN Contour-Mode Resonators with Self-Sustained Oscillator for Volatile Organic Chemical Detection

This paper reports on the design and experimental verification of a new class of nanoscale gravimetric sensors based on ultra-thin-film AlN Contour-Mode Resonant Sensor (CMR-S) functionalized with ss-DNA and connected to a chip-based self-sustaining oscillator loop (fabricated in the ON Semiconductor 0.5 μm CMOS process) for direct frequency read-out. The 220 MHz oscillator based on the ultra-thin AlN CMR-S exhibits an Allan Variance of ∼20 Hz for 100 ms gate time. The sensor affinity for the adsorption of volatile organic chemicals such as 2,6 dinitroluene (DNT, a simulant for explosive vapors) is enhanced by functionalizing the top gold electrode of the device with a thiol-terminated single stranded DNA sequence (Thiol - 5’ CTT CTG TCT TGA TGT TTG TCA AAC 3’) enabling the detection of concentrations as low as 1.5 part per billion (ppb)

Birmingham Urban Climate Laboratory - A high density, urban meteorological dataset, from 2012 -2014

There is a paucity of urban meteorological observations worldwide, hindering progress in understanding and mitigating urban meteorological hazards and extremes. High quality urban datasets are required to monitor the impacts of climatological events, whilst providing data for evaluation of numerical models. The Birmingham Urban Climate Laboratory was established as an exemplar network to meet this demand for urban canopy layer observations. It comprises of an array of 84 wireless air temperature sensors nested within a coarser array of 24 automatic weather stations, with observations available between June 2012 and December 2014. data routinely underwent quality control, follows the ISO 8601 naming format and benefits from extensive site metadata. The data have been used to investigate the structure of the urban heat island in Birmingham and its associated societal and infrastructural impacts. The network is now being repurposed into a testbed for the assessment of crowd-sourced and satellite data, but the original dataset is now available for further analysis, and an open invitation is extended for its academic use

The Birmingham Urban Climate Laboratory: an open meteorological test bed and challenges of the smart city

Existing urban meteorological networks have an important role to play as test beds for inexpensive and more sustainable measurement techniques that are now becoming possible in our increasingly smart cities. The Birmingham Urban Climate Laboratory (BUCL) is a near-real-time, high-resolution urban meteorological network (UMN) of automatic weather stations and inexpensive, nonstandard air temperature sensors. The network has recently been implemented with an initial focus on monitoring urban heat, infrastructure, and health applications. A number of UMNs exist worldwide; however, BUCL is novel in its density, the low-cost nature of the sensors, and the use of proprietary Wi-Fi networks. This paper provides an overview of the logistical aspects of implementing a UMN test bed at such a density, including selecting appropriate urban sites; testing and calibrating low-cost, nonstandard equipment; implementing strict quality-assurance/quality-control mechanisms (including metadata); and utilizing preexisting Wi-Fi networks to transmit data. Also included are visualizations of data collected by the network, including data from the July 2013 U.K. heatwave as well as highlighting potential applications. The paper is an open invitation to use the facility as a test bed for evaluating models and/or other nonstandard observation techniques such as those generated via crowdsourcing techniques

Local-scale urban meteorological parameterization scheme (LUMPS): longwave radiation parameterization and seasonality-related developments

Recent developments to the Local-scale Urban Meteorological Parameterization Scheme (LUMPS), a simple model able to simulate the urban energy balance, are presented. The major development is the coupling of LUMPS to the Net All-Wave Radiation Parameterization (NARP). Other enhancements include that the model now accounts for the changing availability of water at the surface, seasonal variations of active vegetation, and the anthropogenic heat flux, while maintaining the need for only commonly available meteorological observations and basic surface characteristics. The incoming component of the longwave radiation (L↓) in NARP is improved through a simple relation derived using cloud cover observations from a ceilometer collected in central London, England. The new L↓ formulation is evaluated with two independent multiyear datasets (Łódź, Poland, and Baltimore, Maryland) and compared with alternatives that include the original NARP and a simpler one using the National Climatic Data Center cloud observation database as input. The performance for the surface energy balance fluxes is assessed using a 2-yr dataset (Łódź). Results have an overall RMSE < 34 W m−2 for all surface energy balance fluxes over the 2-yr period whe

SmartAQnet – neuer smarter Weg zur räumlichen Erfassung von Feinstaub

Mit dem Forschungsprojekt SmartAQnet wird ein smarter Weg zur räumlichen Bestimmung von Feinstaub untersucht und am Modellstandort Augsburg erprobt. Forschungsansatz ist die Erfassung und Zusammenführung unterschiedlicher Qualitäten von Feinstaubmesswerten mit Fernerkundungsdaten. Feinstaubmesswerte können hierbei von Jedermann (z. B. mit Ultra-Low-Cost-Sensoren) bis hin zu offiziellen Messnetzen (mit hochpräziser Messtechnik) in die Datenarchitektur eingespeist werden. Eine neuartige Internet-of-Things-Analyseplattform soll Daten zur Anwendung sowohl für Planer als auch für den Bürger bieten, welche der nachhaltigen Gesundheitsvorsorge dienen können (z. B. App für eine luftqualitätsbezogene Navigation)