A wireless reference node to provide self-calibration capability to wireless sensors networks

Wireless sensors networks (WSNs) are constantly expanding their application field, from simple two-state measurements (e.g., on/off, proximity detection, etc.) to distributed many-parameter measurements. Commercial WSNs offer a wide range of functions and performance with sensors sometimes achieving accuracy comparable with desktop instrumentation. However, the advantage of using such sensors for in-situ monitoring is often offset by the need of partially dismantling the network at the time of periodic network nodes calibration. As a result, new reference standards suitable for automatic and in-situ calibration of such sensors networks are needed in order to reduce the calibration cost, the inherent inefficiency and the logistic problems of a laboratory calibration, further exploiting the communication capabilities of a WSN. This work discusses the development of a wireless reference node (WRN) for the measuring of environment quantity such as air temperature (T) and relative humidity (RH). The module was developed for accurate measurements of additional environmentrelated quantities whose principle is based on a capacitive sensing mechanism (e.g. pressure, air-flow, moisture, etc…). The WRN performance was investigated in the temperature range from 0 °C to 40 °C and in the relative humidity range from 10 %rh to about 90 %rh for its potential use as a transfer standard for automatic in-situ calibrations. Some of novelties here reported were patented and are now available to upgrade a basic WSN with an automatic in-situ calibration capability

Vapor pressure measurements over supercooled water in the temperature range from −10 1 °C to +10 −2 °C

An accurate measurement of saturation vapor pressure of supercooled water is a strong challenge in metrology, mainly due to difficulties concerning keeping water at a liquid state at temperatures well below the melting point; thus few experimental data covering limited temperature ranges (down to about 253 K) are reported in literature. For this reason, an investigation of the water vapor – supercooled water equilibrium along the saturation line is carried out at Istituto Nazionale di Ricerca Metrologica (INRIM). Measurements cover the temperature range from 261.26 K to 273.25 K, corresponding to a saturation vapor pressure from about 244 Pa to 611 Pa. The experimental apparatus includes a borosilicate glass sample cell, kept in a liquid bath at a constant temperature with millikelvin stability and connected to a manifold where the pressure is measured using a capacitive diaphragm pressure gauge. In this work, the water sample preparation, the measuring method and measurement corrections are reported; moreover, a comparison between experimental and literature data is conducted along with the most used vapor pressure formulations. Measurement results are discussed and uncertainty sources estimated. The resulting expanded relative uncertainty (k = 2) varies from 0.085% at 261.26 K to 0.039% at 273.25 K

Whispering Gallery Mode Resonators for Precision Temperature Metrology Applications

In this work, the authors exploited the whispering gallery mode (WGM) resonator properties as a thermometer. The sensor is made of a cylindrical sapphire microwave resonator in the center of a gold-plated copper cavity. Two coaxial cables act as antennas and excite the WGM standing waves in the cylindrical sapphire at selected resonance frequencies in the microwave range. The system affords a high quality factor that enables temperature measurements with a resolution better than 15 mu K and a measurement standard uncertainty of 1.2 mK, a value approximately three times better than that achieved in previous works. The developed sensor could be a promising alternative to platinum resistance thermometers, both as a transfer standard in industrial applications and as an interpolating instrument for the dissemination of the kelvin

Development of a low-frost point generator operating at sub-atmospheric pressure

A low frost point generator (INRIM 03) operating at sub-atmospheric pressure has been designed and constructed at the Istituto Nazionale di Ricerca Metrologica (INRiM) as part of a calibration facility for upper-air sounding instruments. This new humidity generator covers the frost point temperature range between -99 °C and -20 °C and works at any controlled pressure between 200 hPa and 1100 hPa, achieving a complete saturation of the carrier gas (nitrogen) in a single passage through a stainless steel isothermal saturator. The generated humid gas contains a water vapour amount fraction between 14bold dot10-9 mol/mol and 5bold dot10-3 mol/mol. In this work the design of the generator is reported together with characterisation and performance evaluation tests. A preliminary validation of the INRIM 03 against one of the INRIM humidity standards in the common region is also included. Basing on experimental test results, an initial uncertainty evaluation of the generated frost-point temperature, Tfp, and water vapour amount fraction, xw, in the limited range down to -75 °C at atmospheric pressure is reported. For the frost-point temperature, the uncertainty budget yields a total expanded uncertainty (k=2) of less than 0.028 °C, while for the mole fraction the budget yields a total expanded uncertainty of less than 10-6 mol/mol

Assuring measurement traceability to ATE systems for MEMS temperature sensors testing and calibration

In the framework of an EMPIR joint research project (MET4FoF - Metrology for Factory of Future), a facility is being developed to provide in-situ measurement traceability to next-generation of Automated Test Equipment (ATE) systems used in MEMS temperature sensors testing and calibration. The above measurement traceability concepts are demonstrated in a testbed developed by SPEA in collaboration with INRIM and IPQ. The experimental work comprises both the factory-side implementation and the laboratory-side developments of a special calibration facility, to cover the temperature range between approximately -60 °C and 200 °C. On the factory side, SPEA develops a novel ATE prototype system, based on the concepts of good metrology practice, with the possibility to calibrate/validate in-situ the electronic circuitry and the on-board reference temperature sensors. The novel ATE prototype implements: • An improved temperature control system, with a new design of heaters, temperature sensors and MEMS temperature conditioning features. • A CPU software/firmware improvements to store sensors’ calibration coefficients and allow a “one-touch calibration” feature (i.e. a fully automatic process able to perform a comparison calibration of the ATE on-board reference temperature sensors). • An assessment of thermal conditions (homogeneity, heat losses, boundary effects) to estimate temperature calibration uncertainty. • A so-called “reference fixture”, i.e. an instrumented sensor socket equipped with a network of laboratory-calibrated reference sensors. On the laboratory side, INRIM develops calibration facilities and measurements methods to provide traceable temperature and electrical measurements to the above ATE systems. A custom equipment is developed to accommodate the sensors belonging to the reference fixture in order to calibrate them by comparison in a thermostatic bath. IPQ deals with the numerical simulation, by means of a 3D model of the temperature uniformity of the thermal chuck i.e. the ATE component providing the thermal stimulus to the MEMS under test. The simulation data will be used to help the SPEA hardware designer to improve the type, number and position of reference sensors on the thermal chuck to provide a more reliable and metrologically characterized thermal stimulus. The final paper will describe how an ATE machine works and in which parts it consists and how it is modified to reach the final goal. Furthermore, simulation data will be cross-compared with experimental data coming from metrological characterization before and after the ATE improvements in order to demonstrate their effectiveness. Also the method to assure traceability in large-scale temperature MEMS testing will be detailed and an example of application will be reported. Finally, it is expected that the outcome of this work will impact the quality and reliability of the MEMS sensors largely used in consumer electronics and will extend the calibration capability provided by INRIM to such an expanding industrial sector

Application of plate heat exchangers to the development of portable high-pressure humid gas generators

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The preliminary design and testing of a portable, high-pressure humidity generator based on a corrugated-plate heat exchanger (PHE) is described. It resulted in a very simple system, consisting of a bubbling pre-saturator followed by the PHE used as a condenser. The PHE does not need to be hosted in a liquid bath, resulting in a very compact design whose operation is largely independent from a specific bath - which may be available on site – used to condition the temperature of a circulating counter-flow fluid. Experimental tests were performed on a prototype in order to demonstrate the principle and validate at an early stage the system operation. The efficiency of the PHE as condenser was assessed over a temperature range from 0 °C to 65 °C by varying input and influence parameters, such as the dew point temperature, the gas flow rate and its pressure up to 0.5 MPa. The saturation temperature of the humid gas flow compared favourably with the dew-point temperature as measured by a chilled-mirror hygrometer calibrated against a primary humidity standard. The temperature deviations were below 0.02 °C, with a maximum deviation of 0.04 °C, over the whole range of investigated temperatures and pressures.cf201

Development and preliminary investigation of a modular chamber for calibration of relative humidity instruments

In the scope of the project HUMEA – Expansion of European research capabilities in humidity measurement within the EURAMET EMPIR program, the modular chamber for calibration of relative humidity instruments was designed, manufactured and characterized. The modular chamber consists of arbitrary numbers of aluminum blocks each of which provides accommodation for the one relative humidity probe and also has the fittings for pressure and temperature probes as well as ports for gas sampling and/or supplying. The gas can be supplied from the dew/frost point generator or the larger climatic chamber. In the latter case, the airflow through the chamber can be enhanced by using an additional fan. The preliminary study was carried out to investigate the improvement in temperature uniformity using a new chamber in combination with two climatic chambers. The investigation results show significant improvement in temperature uniformity thus lowering the uncertainties of the calibration of relative humidity instruments

VOICE–Validating Outcomes by Including Consumer Experience: A Study Protocol to Develop a Patient Reported Experience Measure for Aboriginal and Torres Strait Islander Peoples Accessing Primary Health Care

Aboriginal and Torres Strait Islander peoples’ (hereafter respectfully referred to as Indigenous Australians) experiences of health care are shaped by historical, social and cultural factors, with cultural security critical to effective care provision and engagement between services and community. Positive patient experiences are associated with better health outcomes. Consequently, it is an accreditation requirement that primary health care (PHC) services must formally gather and respond to patient feedback. However, currently available patient feedback tools were not developed with Indigenous Australians, and do not reflect their values and world views. Existing tools do not capture important experiences of care of Indigenous Australians in PHC settings, nor return information that assists services to improve care. Consistent with the principles of Indigenous Data Sovereignty, we will co-design and validate an Indigenous-specific Patient Reported Experience Measure (PREM) that produces data by and for community, suitable for use in quality improvement in comprehensive PHC services. This paper presents the protocol of the study, outlining the rationale, methodologies and associated activities that are being applied in developing the PREM. Briefly, guided by an Aboriginal and Torres Strait Islander Advisory Group, our team of Indigenous and non-Indigenous researchers, service providers and policy makers will use a combination of Indigenous methodologies, participatory, and traditional western techniques for scale development. We will engage PHC service staff and communities in eight selected sites across remote, regional, and metropolitan communities in Australia for iterative cycles of data collection and feedback throughout the research process. Yarning Circles with community members will identify core concepts to develop an “Experience of Care Framework”, which will be used to develop items for the PREM. Staff members will be interviewed regarding desirable characteristics and feasibility considerations for the PREM. The PREM will undergo cognitive and psychometric testing

Takotsubo syndrome in a patient with atrial fibrillation after electrical cardioversion: a case report

The paper presents a description of the diagnosis and treatment of takotsubo syndrome in a patient with paroxysmal atrial fibrillation after electrical cardioversion. A case report clearly reflects the need for an integrated diagnostic approach to verify the diagnosis using dynamic echocardiography, electrocardiography, angiographic and tomographic investigations. The complexity of differential diagnosis in this case was an atypical variant of myocardial dysfunction. Follow-up made it possible to track the clinical improvement of the patient and the almost complete normalization of myocardial contractility in terms characteristic of takotsubo syndrome

Expansion of European research capabilities in humidity measurement

Humidity is among the most important measured parameters related to HVAC applications, the storage of food products, industrial and medical gases, textile, paper and many other products requiring humidity measurement and control within certain limits. Humidity measurement techniques are diverse and each presents different challenges for use and calibration for a range of pressures and gases. Over the past few years, the development of humidity sensors and apparatus has matured to a level where traceable calibration is beneficial to all industries in which humidity and moisture measurement and control are important