Surface acoustic wave hydrogen sensor

The present invention provides a delay line SAW device fabricated on a lithium niobate substrate and coated with a bilayer of nanocrystalline or other nanomaterials such as nanoparticles or nanowires of palladiumn and metal free pthalocyanine which will respond to hydrogen gas in near real time, at low (room) temperature, without being affected by CO, O.sub.2, CH.sub.4 and other gases, in air ambient or controlled ambient, providing sensitivity to low ppm levels

Atmospheric Plasma Treatment Enhances the Biosensing Properties of Graphene Oxide-Silver Nanoparticle Composite

This work presents an approach to tailor the properties of the graphene oxide- silver nanoparticle (GO-AgNPs) composite using room temperature atmospheric plasma treatment. In particular, the aerosolized deposition of graphene oxide-silver nanoparticle composite (GO-AgNPs), the rapid reduction of GO at room temperature, and AgNPs surface excitation are investigated in this work. The plasma treatment of aerosolized GO leads to the reduced graphene oxide (rGO) formation which is observed from the increase in D to G band ratio from 0.65 for GO to 1.2 for rGO in the Raman spectra. Scanning Electron Microscopy, Transmission Electron Microscopy, and Selected Area Electron Diffraction patterns show that the plasma treatment leads to the morphological changes and the Electrochemical Impedance spectroscopy results show the improvement in the conductivity of the rGO-AgNP composite. To demonstrate the efficacy of the technique, plasma treated GO and silver nanoparticles (AgNPs) composite is used for the electrode surface modification of the commercial screen-printed electrodes for the cortisol detection. The cyclic voltammetry scans to detect cortisol shows that the sensitivity of the surface modified electrodes is increased after plasma treatment. This room temperature atmospheric plasma annealing technique is of specific interest for rapid processing of nanoparticles on flexible surfaces without subjecting them to elevated temperatures

Rectifying antenna and method of manufacture

In accordance with the present invention, an aperture rectenna is provided where the substrate is transparent and of sufficient mechanical strength to support the fabricated structure above it. An aperture antenna is deposited on the transparent substrate and a metal-insulator-metal (MIM) diode is constructed on top of the aperture antenna. There is an insulating layer between the aperture antenna metal and the metal ground plane optimized to maximize the collection of incident radiation. The top of the structure is capped with a metal ground plane layer, which also serves as the DC connection points for each rectenna element

Impedance-Based Miniaturized Biosensor for Ultrasensitive and Fast Prostate-Specific Antigen Detection

This paper reports the successful fabrication of an impedance-based miniaturized biosensor and its application for ultrasensitive Prostate-Specific Antigen (PSA) detection in standard and real human plasma solution, spiked with different PSA concentrations. The sensor was fabricated using photolithographic techniques, while monoclonal antibodies specific to human PSA were used as primary capture antibodies. Electrochemical impedance spectroscopy (EIS) was employed as a detection technique. The sensor exhibited a detection limit of 1 pg/ml for PSA with minimal nonspecific binding (NSB). This detection limit is an order of magnitude lower than commercial PSA ELISA assays available on the market. The sensor can be easily modified into an array for the detection of other biomolecules of interest, enabling accurate, ultrasensitive, and inexpensive point-of-care sensing technologies

Review—Machine Learning Techniques in Wireless Sensor Network Based Precision Agriculture

The use of sensors and the Internet of Things (IoT) is key to moving the world\u27s agriculture to a more productive and sustainable path. Recent advancements in IoT, Wireless Sensor Networks (WSN), and Information and Communication Technology (ICT) have the potential to address some of the environmental, economic, and technical challenges as well as opportunities in this sector. As the number of interconnected devices continues to grow, this generates more big data with multiple modalities and spatial and temporal variations. Intelligent processing and analysis of this big data are necessary to developing a higher level of knowledge base and insights that results in better decision making, forecasting, and reliable management of sensors. This paper is a comprehensive review of the application of different machine learning algorithms in sensor data analytics within the agricultural ecosystem. It further discusses a case study on an IoT based data-driven smart farm prototype as an integrated food, energy, and water (FEW) system

Exploring Wireless Sensor Network Technology In Sustainable Okra Garden: A Comparative Analysis Of Okra Grown In Different Fertilizer Treatments

The goal of this project was to explore commercial agricultural and irrigation sensor kits and to discern if the commercial wireless sensor network (WSN) is a viable tool for providing accurate real-time farm data at the nexus of food energy and water. The smart garden consists of two different varieties of Abelmoschus esculentus (okra) planted in raised beds, each grown under two different fertilizer treatments. Soil watermark sensors were programed to evaluate soil moisture and dictate irrigation events up to four times a day, while soil temperature and photosynthetic solar radiation sensors also recorded data every six hours. Solar panels harvested energy to power water pump and sensors. The objectives of the experiments were to evaluate and compare plant and soil parameters of the two okra varieties grown under two different fertilizer treatments. The plant parameters evaluated and compared were basal diameter, plant height, fruit production, and fruit size. Soil parameters measured were soil moisture, soil temperature, and soil nitrate concentration. The commercial sensors were evaluated on efficiency, accuracy, ease of use and overall practicality. Clemson spineless produced larger okra plants with the highest plant parameter values, followed by Emerald okra. However, they both averaged nearly the same yield and length of okra fruit. Nature’s Care fertilizer leached more in beds containing Clemson spineless, while Garden-tone leached more in beds containing Emerald okra. When the WSN is installed properly, the system’s great performance undoubtedly aides the farmer by providing real time field data. However, a properly installed apparatus does not promise a stable system. There are numerous challenges and limitations of which can diminish the performance quality of the WSN, those being battery power, data transmission, and data storage. Data storage is also an issue depending on the amount of data collected, rate of data collection, and size of storage unit. These issues can hinder the decision making for precision farmers

New dynamic microreactor system to mimic biofilm formation and test anti-biofilm activity of nanoparticles

Microbial bioflms are composed of surface-adhered microorganisms enclosed in extracellular polymeric substances. The bioflm lifestyle is the intrinsic drug resistance imparted to bacterial cells protected by the matrix. So far, conventional drug susceptibility tests for bioflm are reagent and time-consuming, and most of them are in static conditions. Rapid and easyto-use methods for bioflm formation and antibiotic activity testing need to be developed to accelerate the discovery of new antibioflm strategies. Herein, a Lab-On-Chip (LOC) device is presented that provides optimal microenvironmental conditions closely mimicking real-life clinical bioflm status. This new device allows homogeneous attachment and immobilization of Pseudomonas aeruginosa PA01-EGFP cells, and the bioflms grown can be monitored by fuorescence microscopy. P. aeruginosa is an opportunistic pathogen known as a model for drug screening bioflm studies. The infuence of fow rates on bioflms growth was analyzed by fow simulations using COMSOL® 5.2. Signifcant cell adhesion to the substrate and bioflm formation inside the microchannels were observed at higher fow rates>100 µL/h. After bioflm formation, the efectiveness of silver nanoparticles (SNP), chitosan nanoparticles (CNP), and a complex of chitosan-coated silver nanoparticles (CSNP) to eradicate the bioflm under a continuous fow was explored. The most signifcant loss of bioflm was seen with CSNP with a 65.5% decrease in average live/dead cell signal in bioflm compared to the negative controls. Our results demonstrate that this system is a user-friendly tool for antibioflm drug screening that could be simply applied in clinical laboratories.Fil: Bourguignon, Natalia. Universidad Tecnológica Nacional; Argentina. Florida International University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kamat, Vivek. Florida International University; Estados UnidosFil: Perez, Maximiliano. Universidad Tecnológica Nacional; Argentina. Florida International University; Estados UnidosFil: Mathee, Kalai. Florida International University; Estados UnidosFil: Lerner, Betiana. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Florida International University; Estados UnidosFil: Bhansali, Shekhar. Florida International University; Estados Unido

Hydrothermal Growth of Zinc Oxide (ZnO) Nanorods (NRs) on Screen Printed IDEs for pH Measurement Application

There is considerable interest in nanostructured materials with interdigitated electrodes (IDEs) platforms to detect and monitor the level of various ions in numerous applications. Herein, we report the design and fabrication of IDEs based pH sensor by using hydrothermal growth of ZnO nanorods (NRs). A four-step deposition of ZnO seed layer followed by a hydrothermal treatment lead to the heavily ordered ZnO NRs patterns on the screen printed IDEs. The structural, chemical compositional and electrical properties of the NRs were investigated and examined by using field emission scanning electron microscopy (FeSEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) technique and Keithley 4200 semiconductor characterization system respectively. The sensor capacitance and pH were found to be inversely proportional at a working frequency of 1 kHz. The sensor displayed sensitivity of 1.06 nF/pH in the range of pH 4−10

Electrochemical sensing method for point-of-care cortisol detection in human immunodeficiency virus-infected patients

A novel electrochemical sensing method was devised for the first time to detect plasma cortisol, a potential psychological stress biomarker, in human immunodeficiency virus (HIV)-positive subjects. A miniaturized potentiostat (reconfigured LMP91000 chip) interfaced with a microfluidic manifold containing a cortisol immunosensor was employed to demonstrate electrochemical cortisol sensing. This fully integrated and optimized electrochemical sensing device exhibited a wide cortisol-detection range from 10 pg/mL to 500 ng/mL, a low detection limit of 10 pg/mL, and sensitivity of 5.8 μA (pg mL)-1, with a regression coefficient of 0.995. This cortisol-selective sensing system was employed to estimate plasma cortisol in ten samples from HIV patients. The electrochemical cortisol-sensing performance was validated using an enzyme-linked immunosorbent assay technique. The results obtained using both methodologies were comparable within 2%–5% variation. The information related to psychological stress of HIV patients can be correlated with disease-progression parameters to optimize diagnosis, therapeutic, and personalized health monitoring