Portable Prototype Research Articles

Assessment of soil properties in situ using a prototype portable MIR spectrometer in two agricultural fields

Mid-infrared (MIR) soil spectroscopy has shown applicability to predict selected properties through various laboratory studies. However, reports on the successful use of MIR instruments in field conditions ( in situ ) have been limited. In this study, a small portable prototype MIR (898–1811 cm −1 ) spectrometer was used to collect soil spectra from two agricultural fields (predominantly organic and mineral soils). Both fields were located at Macdonald Campus of McGill University in Ste-Anne-de-Bellevue, Quebec, Canada. In each of the 120 predefined field locations, in situ spectroscopic measurements were repeated three times and one representative soil sample was analyzed following conventional laboratory procedures. For every soil property, a field-specific partial least squares regression (PLSR) model was developed and evaluated using a leave-one-out cross-validation routine. Each soil property was evaluated in terms of the accuracy and reproducibility of model predictions. Among tested soil properties, soil organic matter, water content, bulk density, cation exchange capacity (CEC), Ca and Mg yielded higher model performance indicators (R 2 > 0.50 and RPD > 1.40) as compared to soil pH, Fe, Cu, phosphorus, nitrate-nitrogen, K or Na. In most instances, the error estimate representing the prediction reproducibility was found to be as high as 50% of the overall prediction error. This was due to the combination of optical and electrical noise and soil micro-variability causing soil spectra representing the same field location to yield different predictions.

THE GENERATION OF BUILDING FLOOR PLANS USING PORTABLE AND UNMANNED AERIAL VEHICLE MAPPING SYSTEMS

Indoor navigation or positioning systems have been widely developed for Location-Based Services (LBS) applications and they come along with a keen demand of indoor floor plans for displaying results even improving the positioning performance. Generally, the floor plans produced by robot mapping focus on perceiving the environment to avoid obstacles and using the feature landmarks to update the robot position in the relative coordinate frame. These maps are not accurate enough to incorporate to the indoor positioning system. This study aims at developing Indoor Mobile Mapping System (Indoor MMS) and concentrates on generating the highly accurate floor plans based on the robot mapping technique using the portable, robot and Unmanned Aerial Vehicles (UAV) platform. The proposed portable mapping system prototype can be used in the chest package and the handheld approach. In order to evaluate and correct the generated floor plans from robot mapping techniques, this study builds the testing and calibration field using the outdoor control survey method implemented in the indoor environments. Based on control points and check points from control survey, this study presents the map rectification method that uses the affine transformation to solve the scale and deformation problems and also transfer the local coordinate system into world standard coordinate system. The preliminary results illustrate that the final version of the building floor plan reach 1 meter absolute positioning accuracy using the proposed mapping systems that combines with the novel map rectification approach proposed. These maps are well geo-referenced with world coordinate system thus it can be applied for future seamless navigation applications including indoor and outdoor scenarios.

Micro-optical prototyping of a surface acoustic wave-based point-of-care coagulation assay and first application in anticoagulated patients.

Clinicians demand for methods to monitor effects of direct anticoagulants in the emergency setting. We recently described a coagulation assay based on surface acoustic waves (SAW) technology, which quantifies anticoagulant effects by image processing. Here we describe the first step in miniaturizing this laboratory method and provide a portable prototype that contains the optical illumination and automatic on-board image processing. A device about the size of a shoebox was realized that contains the SAW-chip, the signal generator, the LED illumination, as well as the necessary lenses, aperture, and CCD sensor. The microspheres in the blood were mixed by SAW, and the movement of the microspheres was quantified by on-board image processing. Upon contact with activation induced coagulation, this movement ceases, and coagulation times were measured and compared to the manual methods obtained by standard fluorescent microscopy. A major advantage of our method is the low amount of blood (~ 6 μL) necessary for testing. Results from the prototype correlated accurately with manual methods (Pearson correlation coefficient r = 0.9644). SAW-induced clotting time under anticoagulant treatment with dabigatran or rivaroxaban was well correlated with physicochemically determined plasma concentrations of these DOACs in anticoagulated patients. Compared to manual alignment of the chip under the fluorescence microscope, the prototype had a lower coefficient of variation. The last evolution step towards a point-of-care (POC)-device would be the development of a cartridge (containing calcium chloride and fluorescent label) such that a drop of blood can be introduced into the reaction vessel by a fluid actuator system.

The Feasibility of Flat, Portable and Wireless Device for Non-Invasive Peripheral Oxygenation Measurement over the Entire Body

Peripheral oxygenation level (SpO2) can provide vital information on body functions. Continuous monitoring facilitates effective diagnosis and treatment and can even be lifesaving. Clinical device monitor SpO2 using a clip, and measure light transmission through the tissue. This method limits the body locations of the clip’s placement and is sensitive to body movement, which hampers continuous SpO2 monitoring during wakefulness or sleep, thus decreasing its usability in clinics and its accessibility in homecare usage. We developed a portable, wireless, flat and low cost prototype for continuous monitoring of SpO2 that overcomes those limitations. The prototype enables convenient measurement in larger variety of body locations by spectrophotometric measurements of changes in the optical reflectance unlike other device that measure absorption through the tissue. The original design and signal processing enable reliable signal acquisition, synchronization and control. An Android’s application was developed to provide a user friendly interface for results display on smartphones. The prototype’s measurements were compared to commercial device that simultaneously measured heart rate frequency, transcutaneous oxygen tension (tcPO2) and SpO2. The prototype’s measurements accurately reflected changes caused by blood pulses, were correlated to the heart rate, and were sensitive to changes in oxygen saturation. Excellent real time behavior and synchronization were demonstrated between the hardware and smartphone software. Our prototype thus enables convenient SpO2 measurement over the entire body, while maintaining accuracy comparable to commercial device. Its smartphone application enables accessible and understandable results display to patients, care-givers and healthcare professionals. The application’s display and alert calibration flexibility facilitates the prototype’s usage in changing medical requirements and for various disease and conditions. A device based on this prototype can monitor continuously and accurately patients’ SpO2 without limiting their everyday activities or disturbing their sleep and can thus significantly im-prove their medical care in both clinics and home.

Monitoring breath markers under controlled conditions

Breath analysis has the potential to detect and monitor diseases as well as to reduce the corresponding medical costs while improving the quality of a patient’s life. Herein, a portable prototype, consisting of a commercial breath sampler modified to work as a platform for solid-state gas sensors was developed. The sensor is placed close to the mouth (<10 cm) and minimizes the mouth-to-sensor path to avoid contamination and dilution of the target breath marker. Additionally with an appropriate cooling concept, even high sensor operating temperatures (e.g. 350 °C) could be used. Controlled sampling is crucial for accurate repeatable analysis of the human breath and these concerns have been addressed by this novel prototype. The device helps a subject control their exhaled flow rate which increases reproducibility of intra-subject breath samples. The operation of this flame-made selective chemo-resistive gas sensor is demonstrated by the detection of breath acetone.

Optomechanical reference accelerometer

We present an optomechanical accelerometer with high dynamic range, high bandwidth and readout noise levels below m s−2/. The straightforward assembly and low cost of our device makes it a prime candidate for on-site reference calibrations and autonomous navigation. We present experimental data taken with a vacuum sealed, portable prototype and deduce the achieved bias stability and the accuracy of the sensitivity. Additionally, we present a comprehensive model of the device physics that we use to analyze the fundamental noise sources and accuracy limitations of such devices.

Adaptative ECT system based on reconfigurable electronics

In this work we present a novel scheme for the design of electrical capacitance tomography systems that is based on the use of reconfigurable electronics. The objective of this strategy is to generate an adaptable and portable prototype for the processing electronics, i.e., an instrument suitable to be easily transported and applied to different ECT sensors and scenarios with no need of hardware redesign. In order to show the benefits of this approach, a prototype of the processing electronics for the readings of the inter-electrode capacitance values has been implemented using a Programmable System on Chip (PSoC) that allows configuring both analog and digital blocks included in the design. The result is a compact and portable instrument that can work with any ECT sensor up to 8 electrodes. The measurements are sent through a wireless Bluetooth link to an external smart-device such as smartphone, where the permittivity distribution is reconstructed using a custom-developed Android application.

EyeSelfie

Eye alignment to the optical system is very critical in many modern devices, such as for biometrics, gaze tracking, head mounted displays, and health. We show alignment in the context of the most difficult challenge: retinal imaging. Alignment in retinal imaging, even conducted by a physician, is very challenging due to precise alignment requirements and lack of direct user eye gaze control. Self-imaging of the retina is nearly impossible. We frame this problem as a user-interface (UI) challenge. We can create a better UI by controlling the eye box of a projected cue. Our key concept is to exploit the reciprocity, "If you see me, I see you", to develop near eye alignment displays. Two technical aspects are critical: a) tightness of the eye box and (b) the eye box discovery comfort. We demonstrate that previous pupil forming display architectures are not adequate to address alignment in depth. We then analyze two ray-based designs to determine efficacious fixation patterns. These ray based displays and a sequence of user steps allow lateral (x, y) and depth (z) wise alignment to deal with image centering and focus. We show a highly portable prototype and demonstrate the effectiveness through a user study.

Wearable System for Monitoring of Oxygen Concentration in Breath Based on Optical Sensor

This paper reports the development of a compact, portable prototype for the determination of gaseous oxygen in breath. This system is fully wearable, it can be worn by the user as an armband where the electronics are placed, i.e., connected to a mouthpiece where the breath is sensed. The prototype is based on an optical luminescent sensor consisting of a stabilized porphyrin dye directly deposited onto a color detector. The sensor response, when it is optically excited, is quenched by the surrounding oxygen. The intensity of the generated luminescence is registered by means of a digital color detector whose output data correspond to the coordinates of the RGB color space. For this particular optical sensor, the red coordinate is directly related to the concentration of O2, and it is sent to a remote device such as a smartphone or tablet by a Bluetooth link. An application for Android operative system has also been developed for data visualization and analysis. Employing this novel system, a high resolution in the range of few parts per billion in the determination of oxygen can be achieved.

Designing and testing of a portable filter for groundwater defluoridation and desalination, equipped with non-woven geotextiles

Using non-woven polypropylene geotextile, a filtration unit was designed for portable prototype filter capable of defluoridation and desalination. The filtration unit contains geotextile bag filled with mica and graphite sand. Emphasis was given to make the filter design as simple as possible that is suitable for rural areas. The designed filter was continuously tested for three months along with ceramic (Candle) filter and Pureit filter for comparative studies. The performance of the filters was evaluated on the basis of the percentage of residue removed by the individual filters and cleaning period of the filters. The results of the improvement in the water quality made by prototypes filter without cleaning show reduction in concentration of fluoride and electrical conductivity (EC) by 83.06 and 45.75%, respectively. While the other two filters despite weekly cleaning shows reduction in concentration of fluoride and EC by 74.20 and 30.04%, (ceramic filter) and 93.68 and 86.37% (Pureit filter), respectively. The prototype filter with very simple in design has performed better than other filters with complex designs. The test shows that uses of non-woven geotextiles (polypropylene) along with sand can provide an alternate solution to the expensive defluoridation and desalination processes.

A Digitalized Implementation of Time-of-Flight Measurement for Cable Fault Location

The major technical difficulty of time domain reflectometry (TDR) based cable fault location lies in the accurate measurement of the time of flight (TOF). The measurement of such time intervals is realized by a digital counter together with a reference clock. Theoretical analysis is established to prove that the resolution can be refined to nanosecond by averaging the counting results from a massive number of repetitive measurements. A microcontroller is used to generate a repetitive step signal in order to perform the repetitive test. 8 MHz clock and 8-bit digital counter are used to measure the time of flight. Experimental results showed that the timing resolution of the counter method is improved to nanosecond using the mean of 30,000 times of measurement results. A portable prototype for cable fault location is made to verify such a configuration. Test results showed that the position of the cable fault can be located with error of less than 0.1m.

Environmental Impact Assessment of Hydrometallurgical Processes for Metal Recovery from WEEE Residues Using a Portable Prototype Plant

Life cycle assessment (LCA) was applied to hydrometallurgical treatments carried out using a new portable prototype plant for the recovery of valuable metals from waste electrical and electronic equipment (WEEE). The plant was fed with the WEEE residues from physical processes for the recycling of fluorescent lamps, cathode ray tubes (CRTs), Li-ion accumulators and printed circuit boards (PCBs). Leaching with sulfuric acid was carried out, followed by metal recovery by selective precipitation. A final step of wastewater treatment with lime was performed. The recovered metals included yttrium, zinc, cobalt, lithium, copper, gold, and silver. The category of global warming potential was the most critical one considering the specifications for southern European territories, with 13.3 kg CO(2)/kg recovered metal from the powders/residues from fluorescent lamps, 19.2 kg CO(2)/kg from CRTs, 27.0 kg CO(2)/kg from Li-ion accumulators and 25.9 kg CO(2)/kg from PCBs. Data also show that metal extraction steps have the highest load for the environment. In general, these processes appear beneficial for the environment in terms of CO(2) emissions, especially for metal recovery from WEEE residues from fluorescent lamps and CRTs.

Chemiluminescence detector based on a single planar transparent digital microfluidic device

We report on a compact and portable prototype of chemiluminescence detector based on a single planar single polar transparent electrowetting-on-dielectrics (EWOD) device. The coupling ground model was proposed to build the EWOD device, which could be driven under a single polar voltage. Such a design not only simplified the chip construction and control circuit, but also had the potential for the ball-like droplet to focus the fluorescence and enhance the detection sensitivity. Simulations and experiments both confirmed that the greater the contact angle, the stronger the detected optical signal, and thus the higher the sensitivity. The sensitivity of the prototype detector to H2O2 was 5.45 mV (mmol L(-1))(-1) and the detection limit was 0.01 mmol L(-1) when the contact angle of the EWOD surface was 120°. To further increase the sensitivity and decrease the detection limit, the contact angle of the EWOD device could be increased and the dark current of the photomultiplier decreased. The prototype shows potential applications as highly sensitive, cost effective and portable immuno-detectors, especially as a blood glucose monitor.

An enclosed in-gel PCR amplification cassette with multi-target, multi-sample detection for platform molecular diagnostics

This work describes a self-contained, simple, disposable, and inexpensive gel capillary cassette for DNA amplification in near point of care settings. The cassette avoids the need for pumps or valves during raw sample delivery or polymerase chain reaction (PCR) amplification steps. The cassette contains capillary reaction units that can be stored at room temperature for up to 3 months. The current cassette configuration format simultaneously tests up to 16 patients for two or more targets, accommodates different sample types on the same cassette, has integrated positive and negative controls and allows flexibility for multiple geometries. PCR reagents in the cassette are desiccated to allow storage at room temperature with rehydration by raw sample at the time of testing. The sample is introduced to the cassette via a transfer pipette simply by capillary force. DNA amplification was carried out in a portable prototype instrument for PCR thermal cycling with fluorescence detection of amplified products by melt curve analysis (MCA). To demonstrate performance, raw genital swabs and urine were introduced to the same cassette to simultaneously detect four sexually transmitted infections. Herpes Simplex Viruses (HSV-1 and HSV-2) were detected from raw genital swabs. Ureaplasma urealyticum (UU) and Mycoplasma homonis (MH) were detected from raw urine. Results for multiple patients were obtained in as little as 50 min. This platform allows multiparameter clinical testing with a pre-assembled cassette that requires only the introduction of raw sample. Modification of the prototype device to accommodate larger cassettes will ultimately provide high throughput simultaneous testing of even larger numbers of samples for many different targets, as is required for some clinical applications. Combinations of wax and/or polymer cassettes holding capillary reaction units are feasible. The components of the cassette are suited to mass production and robotic assembly to produce a readily manufactured disposable reaction cassette that can be configured for disease-specific testing panels. Rapid testing with a disposable reaction cassette on an inexpensive instrument will enable on the spot evaluation of patients in the clinic for faster medical decision-making and more informed therapeutic choices.

Long term structural health monitoring by Brillouin fibre-optic sensing: a real case

We report the results of a long term structural health monitoring (SHM) test campaign performed on a concrete bridge. A one-year test campaign was performed by a portable prototype instrument based on stimulated Brillouin scattering in a single-mode optical fibre. The optical fibre sensor was attached along one arch of the bridge using two types of adhesive for comparison purposes. The attached fibre was able to provide the strain distribution along the structure during the one-year test campaign, with a spatial resolution of 1 m. A crack was revealed and correctly localized by the distributed sensor.

Evaluation of a portable ambulatory prototype for automated overnight closed-loop insulin delivery in young people with type 1 diabetes.

To evaluate an ambulatory, portable prototype, overnight automated closed-loop (CL) system and to explore optimal time of CL initiation. We performed a randomized crossover study and compared automated overnight glucose control started at the time of an evening-meal or at bedtime. Eight young people with type 1 diabetes (T1D) on insulin pump therapy [M = 4; age = 14.3 (1.7) yr; HbA1c = 8.2 (1.3)%; mean (SD)] were studied on two occasions at clinical research facility. A standardized self-selected evening meal [70 (11)g CHO] and snack [22 (4)g CHO] accompanied by prandial insulin boluses were given at 18:00 and 21:00 hours, respectively. In random order, automated CL was started at 18:00 or 21:00 hours and ran until 8:00 hours the next day. Basal insulin delivery was automatically adjusted by a model predictive control algorithm based on real-time continuous glucose monitor readings. Overnight plasma glucose levels (between 21:00 and 08:00 hours) were within the target range (71-145 mg/dL) for 82 (59, 98)% of time when CL started at 18:00 hours and 64 (48, 70)% when CL started at 21:00 hours [median (IQR), p = 0.036]. Time spent above 180 mg/dL [8 (0, 17) vs. 13 (3, 26)%, p = 0.310] or below 70 mg/dL [0 (0,7) vs. 0 (0, 8)%, p = 1.000] did not differ between the two occasions. Mean overnight glucose [121 (14) vs. 137 (13) mg/dL, p = 0.731) was also similar. Overnight insulin infusion rates were comparable [0.8 (0.5, 1.3) vs. 0.8 (0.6, 1.4) U/h, p = 0.263]. No interruptions to CL delivery were observed. Automated CL delivery can be applied reliably and safely to control glucose levels overnight in young people with T1D. Tighter glucose levels may be achieved with an earlier time of CL initiation.

Using capacitive deionisation for inland brackish groundwater desalination in a remote location

In this work, a portable prototype of capacitive deionisation (CDI) unit has been used first time in Wilora, a community in a remote area in Northern Territory, Australia, to remove salt from the brackish groundwater. The CDI unit has demonstrated sufficient salinity and hardness removal ability at the remote brackish water source. It was found that increased flow rate resulted in a decrease of the overall total dissolved solids removal efficiency. However, in terms of energy efficiency, a higher flow rate tended to be favourable. With the current CDI unit configuration and local water conditions, 7L/min is recommended as the optimal operational parameter, with an energy consumption of around 1.89kWh/m3 of treated water. The total water recovery rate was between 75 and 80%. The electrosorption of NaCl onto the CDI cell assembly of 100 pair electrodes follows Langmuir adsorption isotherm and the pseudo-first-order adsorption kinetics. The portable CDI unit proves to be a viable alternative solution to brackish water treatment, especially in communities in remote areas where building a reverse osmosis treatment plant is not practical. The data and results shown in this work can be used as guidance for the on-site operation using this emerging technology.

Towards a Portable Prototype Based on Electrochemical Cholinesterase Biosensor to be Assembled to Soldier Overall for Nerve Agent Detection

AbstractIn a previous work we have developed a biosensor able to detect the Sarin gas at a concentration of 0.1 mg/m3 with only 30 s of incubation time [1]. In this work, we modified the biosensor in order to integrate it into a miniaturized prototype. The prototype is composed of the cell in which is inserted the biosensor, a little fan able to sampling air and an electronic circuit. The circuit is able to apply the potential, to register the current, to turn on‐off the fan and eventually give an alarm. The system was tested with paraoxon with satisfactory results.

Mixtures of Essential Oils in an Air Conditioning Prototype to Reduce the Prevalence of Airborne Pathogenic Bacteria

The rationale for this work was to test the possibility of creating a protective atmosphere by using natural compounds to minimize hazards from chemicals and to control the risk of common infections. The antimicrobial activities of essential oils of Agronis fragrans, Cinnamomum zeylanicum, Lavandula angustifolia, Melaleuca alternifolia (tea tree), Melaleuca nesophila (honey myrtle), Pelargonium x asperum (geranium), Pogostemon cablin (patchouli), Thymus serpyllum, and Thymus vulgaris were evaluated against an array of environmental-borne pathogenic bacteria. Gram-positive bacteria included Bacillus subtilis and Staphylococcus aureus; four Gram-negative bacteria covered Acinetobacter baumanii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In addition, eleven isolates of methicillin-resistant S. aureus (MRSA) and a multidrug-resistant A. baumanii were incorporated. In agar disc diffusion tests, cinnamon had shown the strongest activity that could inhibit all pathogens, followed by lemon thyme, honey myrtle and lavender, while pachouli exhibited the weakest inhibition. Though fragonia possessed a broad range of activity against all pathogens, it did not inhibit some of the MRSA isolates. Cinnamon and lemon thyme demonstrated strong activity measured by minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations. In disk volatilization assay, thyme oil demonstrated the greatest inhibition, followed by lemon thyme, while no inhibition from patchouli was observed. Subsequently, the composition of the atmosphere generated by three different oil blends in our invented portable air-conditioning prototype was assessed. The results showed that mixture of oil blend No. 2 can produce good synergistic effect in reducing the prevalence of airborne pathogens, and thus preventing the spreading of infections.

Bridge Monitoring Using Brillouin Fiber-Optic Sensors

We report the results of a static load test performed on a road-bridge with a span length of 44.40 m. The tests were performed by a portable prototype instrument exploiting stimulated Brillouin scattering in optical fibers for deformation and temperature measurements. The optical fiber sensor was able to provide the strain distribution along a supporting beam of the bridge with a spatial resolution of 3 meters and a strain resolution of ±15 με. Comparison of fiber-optic measurements with finite-elements-method (FEM) simulations, as well as with data collected by vibrating wire strain gauges, confirmed the validity of the SBS-based approach in monitoring the deformation of large structures.