Functional-Material-Based Touch Interfaces for Multidimensional Sensing for Interactive Displays: A Review

Multidimensional sensing is a highly desired attribute for allowing human-machine interfaces (HMIs) to perceive various types of information from both users and the environment, thus enabling the advancement of various smart electronics/applications, e.g., smartphones and smart cities. Conventional multidimensional sensing is achieved through the integration of multiple discrete sensors, which introduces issues such as high energy consumption and high circuit complexity. These disadvantages have motivated the widespread use of functional materials for detecting various stimuli at low cost with low power requirements. This work presents an overview of simply structured touch interfaces for multidimensional (x-y location, force and temperature) sensing enabled by piezoelectric, piezoresistive, triboelectric, pyroelectric and thermoelectric materials. For each technology, the mechanism of operation, state-of-the-art designs, merits, and drawbacks are investigated. At the end of the article, the author discusses the challenges limiting the successful applications of functional materials in commercial touch interfaces and corresponding development trends

Development of sensors and non-destructive techniques to determine the performance of coatings in construction

The primary objective of this work was to examine and develop techniques for monitoring the degradation of Organically Coated Steel (OCS) in-situ. This included the detection of changes associated with the weathering to both the organic coating and metallic substrate. Initially, a review of current promising techniques was carried out however many were found to be unsuitable for this application and the adaptation of current techniques and the development of new techniques was considered. A brief concept investigation, based on initial testing and considerations, was used to determine a number of sensing techniques to examine. These included embedded, Resonant Frequency Identification (RFID), Magnetic Flux Leakage (MFL) and dielectric sensing. Each of these techniques were assessed for the application, prototyped, and tested against a range of samples to determine the accuracy and sensitivity of degradation detection provided. A range of poorly and highly durable coated samples were used in conjunction with accelerated weathering testing for this aim. Track based electronic printed sensors were presented as both a cut edge corrosion tracking and coating capacitance measurement method. While suffering somewhat from electrical paint compatibility issues both concepts showed merit in initial trials however the capacitive sensor ultimately proved insufficiently responsive to coating changes. The embedded, progressive failure-based, cut edge corrosion sensor was produced and tested in modern coating systems with moderate success. Novel applications of RFID and MLF techniques were considered and proved capable of detecting large changes in substrate condition due to significant corrosion. However, there was a lack of sufficient sensitivity when considering early-stage corrosion of durable modern OCS products. Finally, it was shown that a chipless antenna could be designed and optimised for novelly monitoring the changes to the dielectric properties of a paint layer due to degradation. However, ultimately this test, due to equipment requirements, lent itself more to lab testing than in-situ. Due to some of these limitations a different approach was considered in which the environmental factors influencing degradation were examined with the aim of relating these to performance across a building. It was observed that a combination of high humidity and the build-up of aggressive natural deposits contributed to high degradation rates in sheltered regions, such as building eaves, where microclimates were created. The build-up of deposits and their effect was presented as a key degradation accelerant during in-use service. A unique numerical simulation approach was developed to predict the natural washing, via rain impact and characteristics of the building analysed. This approach showed promise for determining areas unlikely to be naturally washed, and therefore subjected to a degradation accelerating, build-up of deposits. Given these understandings coated wetness sensors were considered as a realistic live-monitoring device capable of determining deposit build up and ultimately OCS lifetime

Embedded Sensors to Monitor Production of Composites : From Infusion to Curing of Resin

The need for using light-weight and high-strength fibre reinforced polymer in different applications has increased in the past few decades. The ideal product offers excellent mechanical and chemical properties with much lower weight compared to traditionally used metals. Initially, the fibre-reinforced polymers are being produced by trial and error iterations. This causes a very expensive product, with random quality and lack of reproducibility. There is a need to replace trial and error experiments with knowledge-based approaches. Using sensors for in-situ production to monitor the results in a reliable and repeatable way gives a high-quality composite product and optimizes the time and cost of the process. One of the common manufacturing processes of fibre-reinforced polymer composite is resin infusion in dry fabrics. The resin impregnates the fibrous textile through the existence of a pressure gradient in the fibrous mat, which is generated by a vacuum pump or by a resin injection at high pressure. The impregnation of the dry textile is a result of the pressure gradient between resin inlet and venting point in the mold. Therefore, the most relevant measurement to detect the resin front and the changes of resin hydrostatic pressure is measuring the pressure directly inside the laminate. In this study, pressure sensors provide real-time information about the resin front in laminate and the changes of resin hydrostatic pressure during the infusion. Different pressure sensors and interconnection techniques were examined to minimize the size of the sensing element in the composite. After complete impregnation of the fibres, the curing degree of the resin has to be measured. Microscale interdigital capacitive sensors with a perforated substrate of polyimide are designed and fabricated. The sensors are fabricated on polyimide substrate with a thickness of about 5 micrometers. The polyimide is thermally stable up to 450 degree celsius. Therefore, the sensor can be used for a variety of processes even with high-temperature curing requirements. They have a volume of around 0.1 mm3. The miniaturized dimensions of the sensor enables it to remain in the composite product with the negligible diminishing of mechanical properties. The metallization of the sensor is insulated with metal oxide built up from the metallization itself. This insulation layer enables measurement in electrically conductive carbon fibres. The sensors will remain inside the composite material for structural health monitoring during the life-time of composite. Ideally, the sensors for online process monitoring of composites should be made of the identical fibres or resin in that composite. This will eliminate the wound effect in the host material. To obtain sensorial material, a high-performance resin for aerospace application, type RTM6, is mixed with different plasticizers. The cured mixture of the resin is thin and flexible. An interdigital comb structure is screen-printed on the newly developed substrate. The curing degree of the RTM6 resin in glass and carbon fibres is measured by screen-printed planar interdigital sensor on flexible RTM6. Having sensors for online process monitoring is important for industry 4.0 to autonomously produce fibre reinforced composites in a so-called smart factory . Both, pressure sensors and interdigital capacitive sensors in this thesis can be used for online process monitoring. They will provide a knowledge-based approach for high-quality and low-cost products

Integrated silicon pressure sensors using wafer bonding technology

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 151-156).by Lalitha Parameswaran.Ph.D

Improvements for the 3D printing process based on an FDM printer

El TFG esta realizado sobre una impresora 3D de la marca Ultimaker. Consta de 3 partes diferentes. La primera es la búsqueda y creación de un sistema de auto calibrado de la base sobre la que se imprime. La segunda analiza los diferentes parámetros que influyen en el proceso de impresión. Por ultimo se analizan los fallos que aparecen al imprimir paredes delgadas en diferentes materiales plásticos, buscando posibles soluciones.Departamento de Química AnalíticaGrado en Ingeniería Mecánic

NASA Tech Briefs, November 2010

Topics covered include: Portable Handheld Optical Window Inspection Device; Salience Assignment for Multiple-Instance Data and Its Application to Crop Yield Prediction; Speech Acquisition and Automatic Speech Recognition for Integrated Spacesuit Audio Systems ; Predicting Long-Range Traversability from Short-Range Stereo-Derived Geometry; Browser-Based Application for Telemetry Monitoring of Robotic Assets; Miniature Low-Noise G-Band I-Q Receiver; Methods of Using a Magnetic Field Response Sensor Within Closed, Electrically Conductive Containers; Differential Resonant Ring YIG Tuned Oscillator; Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines; Reducing Seal Adhesion in Low Impact Docking Systems; Optimal Flow Control Design; Corrosion-Resistant Container for Molten-Material Processing; Reusable Hot-Wire Cable Cutter; Deployment of a Curved Truss; High-Volume Airborne Fluids Handling Technologies to Fight Wildfires; Modeling of Alkane Oxidation Using Constituents and Species; Fabrication of Lanthanum Telluride 14-1-11 Zintl High-Temperature Thermoelectric Couple; A Computer Model for Analyzing Volatile Removal Assembly; Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature; Optical Sidebands Multiplier; Single Spatial-Mode Room-Temperature-Operated 3.0 to 3.4 micrometer Diode Lasers; Self-Nulling Beam Combiner Using No External Phase Inverter; Portable Dew Point Mass Spectrometry System for Real-Time Gas and Moisture Analysis; Maximum Likelihood Time-of-Arrival Estimation of Optical Pulses via Photon-Counting Photodetectors; Handheld White Light Interferometer for Measuring Defect Depth in Windows; Decomposition Algorithm for Global Reachability on a Time-Varying Graph; Autonomous GN and C for Spacecraft Exploration of Comets and Asteroids; Efficient Web Services Policy Combination; Using CTX Image Features to Predict HiRISE-Equivalent Rock Density; Isolation of the Paenibacillus phoenicis, a Spore-Forming Bacterium; Monolithically Integrated, Mechanically Resilient Carbon-Based Probes for Scanning Probe Microscopy; Cell Radiation Experiment System; Process to Produce Iron Nanoparticle Lunar Dust Simulant Composite; Inversion Method for Early Detection of ARES-1 Case Breach Failure; Use of ILTV Control Laws for LaNCETS Flight Research;and Evaluating Descent and Ascent Trajectories Near Non-Spherical Bodies

Production accompanying testing of the ATLAS Pixel module

The ATLAS Pixel detector, innermost sub-detector of the ATLAS experiment at LHC, CERN, can be sensibly tested in its entirety the first time after its installation in 2006. Because of the poor accessibility (probably once per year) of the Pixel detector and tight scheduling the replacement of damaged modules after integration as well as during operation will become a highly exposed business. Therefore and to ensure that no affected parts will be used in following production steps, it is necessary that each production step is accompanied by testing the components before assembly and make sure the operativeness afterwards. Probably 300 of about total 2000 semiconductor hybrid pixel detector modules will be build at the Universität Dortmund. Thus a production test setup has been build up and examined before starting serial production. These tests contain the characterization and inspection of the module components and the module itself under different environmental conditions and diverse operating parameters. Once a module is assembled the operativeness is tested with a radioactive source and the long-time stability is assured by a burn-in. A fully electrical characterization is the basis for module selection and sorting for the ATLAS Pixel detector. Additionally the charge collection behavior of irradiated and non irradiated modules has been investigated in the H8 beamline with 180 GeV pions