▶ Present work shows design, fabrication and functional characterization of a very low cost energy autonomous, maintenance free, flexible and wearable micro thermoelectric generator (μTEG). ▶ The ...preliminary prototype integrates an array of 100 thin films thermocouples of Sb2Te3 and Bi2Te3. ▶ At real operation conditions (thermal gradient of 15°C), device generates an open circuit output voltage of about 160mV, electrical output power up to 4.18nW. ▶ Deposition investigation of Sb2Te3 and Bi2Te3 thin films alloys on Kapton HN polyimide foil by RF magnetron co-sputtering technique is discussed. ▶ Deposition parameters have been optimized to gain perfect stoichiometric ratio and high thermoelectric power factor.
In this work we proposed design, fabrication and functional characterization of a very low cost energy autonomous, maintenance free, flexible and wearable micro thermoelectric generator (μTEG), finalized to power very low consumption electronics ambient assisted living (AAL) applications. The prototype, integrating an array of 100 thin films thermocouples of Sb2Te3 and Bi2Te3, generates, at 40°C, an open circuit output voltage of 430mV and an electrical output power up to 32nW with matched load. In real operation conditions of prototype, which are believed to be very close to a thermal gradient of 15°C, the device generates an open circuit output voltage of about 160mV, with an electrical output power up to 4.18nW.
In the first part of work, deposition investigation Sb2Te3 and Bi2Te3 thin films alloys on Kapton HN polyimide foil by RF magnetron co-sputtering technique is discussed. Deposition parameters have been optimized to gain perfect stoichiometric ratio and high thermoelectric power factor; fabricated thermogenerator has been tested at low gradient conditioned to evaluate applications like human skin wearable power generator for ambient assisted living applications.
► This is the first systematic study on the volatile profile of Negroamaro wines. ► This work identified and quantified all the wine volatile compounds. ► The calculated odourant concentrations were ...correlated to wine sensory features. ► For the first time aromatic patterns typical of Negroamaro wine were identified. ► The paper contributes to the discussion about wine geographical origin and variety.
Volatile composition of monovarietal young red wines made from Negroamaro cultivar, an autochthonous grape variety of Vitis vinifera grown exclusively in Salento area (southeast of Italy in Apulia region), was investigated. Volatile compounds were extracted following a solid phase extraction (SPE) method, and then analysed by gas chromatography–mass spectrometry (GC/MS). Results showed a complex aroma profile rich in alcohols, esters and fatty acids, with a minor contribute from aldehydes, lactones, volatile phenols and sulphur compounds. For the first time, aromatic patterns that characterise wines produced from Negroamaro autochthonous grape variety were established, starting a fundamental register of typicity and geographical identity of Apulians wines. Statistical data analysis techniques (Principal component analysis (PCA) and ANOVA) showed the structure of the experimental data and the significant differences for each compound in the different wines.
•Sensorized Si-based water-propellant Vaporizing Liquid Microthurster.•Embedded Temperature and Vapor Fraction Sensors for flow instability control.•Sensor signals correlated to optical acquisition ...of flow within the microchannels.•In-channel water vaporization enhanced by microtextured substrate.•Reliable measurement of vaporization level inside each channel.
Rapid advances in micro/nanotechnology have enabled to achieve high levels of miniaturization, promoting the development of low cost and highly efficient microsystems for specific applications. In the space sector, the miniaturization of satellites has led to a renewed interest in the research and development of advanced micro-propulsion technologies able to generate small and accurate thrust forces and high specific impulse.
This work presents the design and fabrication of a silicon-based water-propellant Vaporizing Liquid Microthurster (VLM) equipped with embedded microsensors for real-time monitoring of in-channel vapor/liquid fraction and fluid temperature during its operation. Anisotropic dry etching of silicon wafer and thermo-compressive bonding were chosen as key fabrication steps: the former process was used to better control the surface roughness on microchannels inner walls, the latter was used to guarantee the fluidic tightness and complete the fabrication process of the device. Borofloat 33 glass, used to seal the micromachined silicon wafer, allows the optical inspection of the fluid flow and vaporization within the different chambers during the device operation. A platinum resistive heater placed on the bottom of the chip was exploited for the heating of the propellant. A set of Resistive Temperature Detectors (RTDs) and, for the first time, capacitive sensors were designed and integrated inside the microthruster chip to add distributed sensing capabilities for flow instability control. Further, a secondary low-power platinum thin film resistive heater was placed inside each of the eight channels, in order to allow for localized precision fluid heating and flow control. The operational feasibility of the fabricated microthruster was assessed by means of a preliminary characterization of the embedded sensors, based on experimental tests supported by numerical investigations; the results demonstrated that the designed microsensor devices are able to maximize the microthruster efficiency, in terms of microtexture-enhanced in-channel water vaporization and reduced power consumption.
Oncostatin M (OSM) is an interleukin-6 (IL-6) member family cytokine implicated in the pathogenesis of chronic diseases including inflammatory bowel disease (IBD). OSM is a novel diagnostic biomarker ...over-expressed in the serum of IBD patients. This paper reports on the first electrochemical OSM immunosensor, developed using a multistep fabrication process aimed at covalently immobilizing OSM antibodies on a mixed self-assembled monolayer coated gold working electrode. Cyclic voltammetry, atomic force microscopy (AFM), IR spectroscopy and optical characterizations were used to validate the sensor functionalization protocol. Electrochemical impedance spectroscopy (EIS) measurements were performed to assess the reliability of the immunosensor preparation and to verify the antibody-antigen complexes formation. The label-free immunosensor showed high sensitivity identifying OSM at clinically relevant concentrations (37–1000 pg mL−1) with low detection limit of 2.86 pg mL−1. Both sensitivity and selectivity of the proposed immunosensor were also demonstrated in human serum in the presence of interfering biomarkers, making it an innovative potential platform for the OSM biomarker detection in IBD patients’ serum.
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•First electrochemical immunosensor developed to detect OSM biomarker in serum.•A covalently immobilization of OSM antibodies was performed on gold electrodes.•The immunosensor exhibited a low detection limit by EIS measurements.•Detection in serum in the presence of interfering species was performed.•The immunosensor represents a potential tool for early diagnosis of IBD.
Fe3O4/γ-Fe2O3 nanoparticles (NPs) based thin films were used as active layers in solid state resistive chemical sensors. NPs were synthesized by high temperature solution phase reaction. Sensing NP ...monolayers (ML) were deposited by Langmuir–Blodgett (LB) techniques onto chemoresistive transduction platforms. The sensing ML were UV treated to remove NP insulating capping. Sensors surface was characterized by scanning electron microscopy (SEM). Systematic gas sensing tests in controlled atmosphere were carried out toward NO2, CO, and acetone at different concentrations and working temperatures of the sensing layers. The best sensing performance results were obtained for sensors with higher NPs coverage (10 ML), mainly for NO2 gas showing interesting selectivity toward nitrogen oxides. Electrical properties and conduction mechanisms are discussed.
This study reports on the fabrication and characterization of an event detection subsystem composed of a flexible piezoelectric pressure sensor and the electronic interface to be integrated into an ...implantable artificial pancreas (IAP) for diabetic patients. The developed sensor is made of an AlN layer, sandwiched between two Ti electrodes, sputtered on Kapton substrate, with a preferential orientation along c-axis which guarantees the best piezoelectric response. The IAP is made of an intestinal wall-interfaced refilling module, able to dock an ingestible insulin capsule. A linearly actuated needle punches the duodenum tissue and then the PDMS capsule to transfer the insulin to an implanted reservoir. The device is located at the connection of the needle with the linear actuator to reliably detect the occurred punching of the insulin-filled capsule. Finite Element Analysis (FEA) simulations were performed to evaluate the piezoelectric charge generated for increasing loads in the range of interest, applied on both the sensor full-area and footprint area of the Hamilton needle used for the capsule punching. The sensor-interface circuit was simulated to estimate the output voltage that can be obtained in real operating conditions. The characterization results confirmed a high device sensitivity during the punching, in the low forces (0-4 N) and low actuator speed (2-3 mm/s) ranges of interest, meeting the requirement of the research objective. The choice of a piezoelectric pressure sensor is particularly strategic in the medical field due to the request of self-powered implantable devices which do not need any external power source to output a signal and harvest energy from natural sources around the patient.
The cellulose industry depends heavily on water owing to the hydrophilic nature of cellulose fibrils and its potential for sustainable and innovative production methods. The emergence of ...nanocellulose, with its excellent properties, and the incorporation of nanomaterials have garnered significant attention. At the nanoscale level, nanocellulose offers a higher exposure of hydroxyl groups, making it more intimate with water than micro- and macroscale cellulose fibers. Gaining a deeper understanding of the interaction between nanocellulose and water holds the potential to reduce production costs and provide valuable insights into designing functional nanocellulose-based materials. In this review, water molecules interacting with nanocellulose are classified into free water (FW) and bound water (BW), based on their interaction forces with surface hydroxyls and their mobility in different states. In addition, the water-holding capacity of cellulosic materials and various water detection methods are also discussed. The review also examines water-utilization and water-removal methods in the fabrication, dispersion, and transport of nanocellulose, aiming to elucidate the challenges and tradeoffs in these processes while minimizing energy and time costs. Furthermore, the influence of water on nanocellulose properties, including mechanical properties, ion conductivity, and biodegradability, are discussed. Finally, we provide our perspective on the challenges and opportunities in developing nanocellulose and its interplay with water.
Wood is one of the most abundant biomaterials on Earth, which has been used for centuries in construction applications including furniture, roofing, flooring, and cabinetry. However, wood chips—which ...are a low-quality and plentiful waste byproduct of lumber milling, woodworking, and shipping operations—have low economic value and complicated disposal methods. In this paper, we propose a strategy for wood chip reuse through the fabrication of bio-based building insulation foam. Through a high-temperature chemical treatment delignification process, we introduced additional small pores within the wood chips, effectively lowering their thermal conductivity, and used them in combination with a binding agent to produce a porous insulation foam. The porous insulation foam achieved a low thermal conductivity of 0.038 W/(m·K) and a high compressive strength of 1.1 MPa (70% strain). These characteristics demonstrate that wood waste can be repurposed into an effective building material, addressing challenges in both waste management and sustainable construction.
Preventing the flow separation could enhance the performance of propulsion systems and future civil aircraft. To this end, a fast detection of boundary layer separation is mandatory for a sustainable ...and successful application of active flow control devices, such as plasma actuators. The present work reports on the design, fabrication and functional tests of low-cost capacitive pressure sensors coupled with dielectric barrier discharge (DBD) plasma actuators to detect and then control flow separation. Finite element method (FEM) simulations were used to obtain information on the deflection and the stress distribution in different-shaped floating membranes. The sensor sensitivity as a function of the pressure load was also calculated by experimental tests. The results of the calibration of different capacitive pressure sensors are reported in this work, together with functional tests in a wind tunnel equipped with a curved wall plate on which a DBD plasma actuator was mounted to control the flow separation. The flow behavior was experimentally investigated by particle image velocimetry (PIV) measurements. Statistical and spectral analysis, applied to the output signals of the pressure sensor placed downstream of the profile leading edge, demonstrated that the sensor is able to discriminate different ionic wind velocity and turbulence conditions. The sensor sensitivity in the 0-100 Pa range was experimentally measured and it ranged between 0.0030 and 0.0046 pF Pa−1 for the best devices.
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