There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

In this Progress Report we provide an update on recent developments in inkjet printing technology and its applications, which include organic thin-film transistors, light-emitting diodes, solar cells, conductive structures, memory devices, sensors, and biological/pharmaceutical tasks. Various classes of materials and device types are in turn examined and an opinion is offered about the nature of the progress that has been achieved.

Inkjet Printing—Process and Its Applications

Human skin is a remarkable organ. It consists of an integrated, stretchable network of sensors that relay information about tactile and thermal stimuli to the brain, allowing us to maneuver within our environment safely and effectively. Interest in large-area networks of electronic devices inspired by human skin is motivated by the promise of creating autonomous intelligent robots and biomimetic prosthetics, among other applications. The development of electronic networks comprised of flexible, stretchable, and robust devices that are compatible with large-area implementation and integrated with multiple functionalities is a testament to the progress in developing an electronic skin (e-skin) akin to human skin. E-skins are already capable of providing augmented performance over their organic counterpart, both in superior spatial resolution and thermal sensitivity. They could be further improved through the incorporation of additional functionalities (e.g., chemical and biological sensing) and desired properties (e.g., biodegradability and self-powering). Continued rapid progress in this area is promising for the development of a fully integrated e-skin in the near future.

25th Anniversary Article: The Evolution of Electronic Skin (E-Skin): A Brief History, Design Considerations, and Recent Progress

Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption

Fiber‐Based Wearable Electronics: A Review of Materials, Fabrication, Devices, and Applications

A sensor comprises a substrate having nanoparticles of a conducting polymer such as polyanaline printed thereon. Also described is a printing composition for printing onto a substrate, the composition comprising nanoparticles of a conducting polymer such as polyanaline.

Sensor comprising conducting polymer materials

A miniaturized, flexible, and low-cost capillary ion chromatography system has been developed for anion analysis in water. The ion chromatography has an open platform, modular design, and allows for ease of modification. The assembled platform weighs ca. 0.6 kg and is 25 × 25 cm in size. Isocratic separation of common anions (F- , Cl- , NO2- , Br- , and NO3- ) could be achieved in under 15 min using sodium benzoate eluent at a flow rate of 3 μL/min, a packed capillary column (0.150 × 150 mm) containing Waters IC-Pak 10 μm anion exchange resin, and light-emitting diode based indirect UV detection. Several low UV light-emitting diodes were assessed in terms of sensitivity, including a new 235 nm light-emitting diode, however, the highest sensitivity was demonstrated using a 255 nm light-emitting diode. Linear calibration ranges applicable to typical natural water analysis were obtained. For retention time and peak area repeatability, relative standard deviation values ranged from 0.60-0.95 and 1.95-3.53%, respectively. Several water samples were analysed and accuracy (recovery) was demonstrated through analysis of a prepared mixed anion standard. Relative errors of -0.36, -1.25, -0.80, and -0.76% were obtained for fluoride, chloride, nitrite, and nitrate, respectively.

Miniaturized capillary ion chromatograph with UV light-emitting diode based indirect absorbance detection for anion analysis in potable and environmental waters

Herein we present a novel sensor for the detection of monosaccharides (e.g. glucose, fructose) in solution, using electrical impedance spectroscopy. The sensor is based on carbon interdigitated electrodes, printed on paper using screen printing. The surface of the electrodes was modified with a thin layer of hydrogel containing acrylamide copolymerised with 20 mol% 3-(Acrylamido)phenylboronic acid (PBA). It was observed that the hydrogel layers containing 20 mol% PBA swell considerably in the presence of glucose and fructose. This in turn changes the measured impedance across the electrodes, making it a suitable sensor for the quantitative detection of saccharides. We investigated the impedance and capacitance variations with different concentrations of glucose and fructose (0–5 mM) in aqueous phosphate buffer solutions. Variations in impedance were attributed to changes in the dielectric properties of the hydrogel under an applied electric field, due to swelling of the hydrogel layer induced by uptake and binding of sugar molecules to the boronate species within the gel. Impedance measurements at 1 kHz demonstrated that hydrogel swelling leads to an increased mobility of ions within the swollen hydrogel layer. The impedance decreased with increasing sugar concentration and the relative capacitance curves are markedly different for fructose and glucose, as the hydrogel exhibits greater swelling in the presence of fructose than glucose over the same concentration range. As the proposed sensor was shown to be suitable for the detection of glucose at concentration levels found in human sweat, future work will focus on the incorporation of these modified paper-based electrodes into wearable skin patches for non-invasive sugar monitoring in sweat.

/pdf/impedance-spectroscopy-for-monosaccharides-detection-using-59pmpyolt5.pdf

Impedance spectroscopy for monosaccharides detection using responsive hydrogel modified paper-based electrodes.

The development and characterisation of a screen-printed tattoo sensor for the non-invasive assessment of the skin barrier is presented. A screen-printed silver tattoo sensor comprising two concentric circle electrodes was fabricated and applied and characterised initially on a soft tissue mimic. It was shown that the tattoo was capable of tracking changes in water content in the soft tissue mimic using impedance spectroscopy. The tattoo sensors were then applied to porcine and human skins and impedance spectroscopy was used to interrogate the skin at the outer stratum corneum (SC). The SC is a layer of great interest from a dermatological point of view since it plays a critical role in the barrier function of the skin by protecting underlying tissue from infection, dehydration, chemical irritants and mechanical stress. Hydration changes were tracked in the skin using the impedance approach and validated against a tissue dielectric constant (TDC) measurement taken with the MoistureMeterD (MMD, Delfin Technologies). The impedimetric results obtained using the tattoo sensor were modelled into proposed circuit models representative of the systems measured. From this study, the potential of using wearable tattoo electrodes coupled with impedance spectroscopy as a transduction technique, to investigate skin barrier status offers considerable promise towards the monitoring and self-management of skin health.

Screen‐printed Tattoo Sensor towards the Non‐invasive Assessment of the Skin Barrier

The subject of electrochemical sensors is broad, spanning many aspects of physical and analytical chemistry, materials science, biochemistry, solid-state physics, device fabrication, electrical engineering, and even statistical analysis. Thus, the field of electrochemical sensors cannot be dealt with holistically in a single chapter. Here, we will focus on electrochemical sensor technology from an analytical perspective, where the rigours of sensor behaviour will be discussed as they relate to the quality of the quantitative information that can be derived. The definition of analytical chemistry was given by the Federation of European Chemical Societies (FECS) in 1993 [1] and adopted by IUPAC:

/pdf/electroanalytical-sensor-technology-2a6aod8a37.pdf

Aoife Morrin

Papers

Sensor comprising conducting polymer materials

Miniaturized capillary ion chromatograph with UV light-emitting diode based indirect absorbance detection for anion analysis in potable and environmental waters

Impedance spectroscopy for monosaccharides detection using responsive hydrogel modified paper-based electrodes.

Screen‐printed Tattoo Sensor towards the Non‐invasive Assessment of the Skin Barrier

Electroanalytical Sensor Technology