Experimental Analysis of Modified CNTs-Based Gas Sensor

As a significant equipment in power system, the operation condition of transformers directly determines the safety of power system. Therefore, it has been an indispensable measure to detect and analyze the dissolved gases in transformers, aiming to estimate the early potential faults in oil‐insulated transformers. In this chapter, the adsorption processes between modified carbon nanotubes (CNTs) (CNTs‐OH, Ni‐CNTs) and dissolved gases in transformers oil including C2H2, C2H4, C2H6, CH4, CO, and H2 have been simulated based on the first principle theory. Meanwhile, the density of states (DOS), adsorption energy, charge transfer amount, and adsorption distance of adsorption process between CNTs and dissolved gases were calculated. Moreover, two kinds of sensors, mixed acid‐modified CNTs and NiCl2‐modified CNTs, are prepared to conduct the dissolved gases response experiment. Then, the gas response mechanisms were investigated. Finally, the results between response experiment and theoretical calculation were compared, reflecting a good coherence with each other. The CNTs gas sensors possess a relatively high sensitivity and fine linearity, and could be employed in dissolved gas analysis equipment in transformer

Adsorption Properties of Typical Lung Cancer Breath Gases on Ni-SWCNTs through Density Functional Theory

A lot of useful information is contained in the human breath gases, which makes it an effective way to diagnose diseases by detecting the typical breath gases. This work investigated the adsorption of typical lung cancer breath gases: benzene, styrene, isoprene, and 1-hexene onto the surface of intrinsic and Ni-doped single wall carbon nanotubes through density functional theory. Calculation results show that the typical lung cancer breath gases adsorb on intrinsic single wall carbon nanotubes surface by weak physisorption. Besides, the density of states changes little before and after typical lung cancer breath gases adsorption. Compared with single wall carbon nanotubes adsorption, single Ni atom doping significantly improves its adsorption properties to typical lung cancer breath gases by decreasing adsorption distance and increasing adsorption energy and charge transfer. The density of states presents different degrees of variation during the typical lung cancer breath gases adsorption, resulting in the specific change of conductivity of gas sensing material. Based on the different adsorption properties of Ni-SWCNTs to typical lung cancer breath gases, it provides an effective way to build a portable noninvasive portable device used to evaluate and diagnose lung cancer at early stage in time

Morphology Control of Tin Oxide Nanostructures and Sensing Performances for Acetylene Detection

Morphology Control plays an important role in gas sensing properties of metal oxide semiconductor based gas sensors. In this study, various morphologies of SnO2 nanostructures including nanobulks, nanospheres, nanorods, and nanowires were successfully synthesized via a simple hydrothermal method assisted with different surfactants. X-ray powder diffraction and scanning electron microscopy were employed to characterize the prepared products. Gas sensors were fabricated by screen-printing the as-prepared SnO2 nanostructures onto planar ceramic substrates. Moreover, their gas sensing properties were systematically investigated towards acetylene gas (C2H2), an important fault hydrocarbon dissolved in power transformer oil. Experiments indicate that the SnO2 nanowires based sensor exhibits excellent gas sensing properties, such as lower operating temperature, higher gas response, quicker response-recovery time and good stability than those of SnO2 nanobulks, nanospheres and nanorods. These results imply SnO2 nanowires a promising sensing morphology for C2H2 detection and provide us a feasible way to develop high-performance gas sensor by tailoring the microstructures and morphologies of the materials in further

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry was held on 1–15 July 2021. The scope of this online conference was to gather experts that are well-known worldwide who are currently working in chemical sensor technologies and to provide an online forum for the presention and discussion of new results. Throughout this event, topics of interest included, but were not limited to, the following: electrochemical devices and sensors; optical chemical sensors; mass-sensitive sensors; materials for chemical sensing; nano- and micro-technologies for sensing; chemical assays and validation; chemical sensor applications; analytical methods; gas sensors and apparatuses; electronic noses; electronic tongues; microfluidic devices; lab-on-a-chip; single-molecule sensing; nanosensors; and medico-diagnostic testing

Applications of Molecularly Imprinted Films

Molecularly imprinted polymers are materials that have voids that are complementary in shape, size, and electronic environment to a specific molecule used for preparation, known as the template. These voids are specific recognition sites that bind the templates preferentially and are used specifically for biomimetic sensors and for solid-phase extraction. Because the specific surface is very important during this process, the use of films and membranes is preferred. This book contains four articles dedicated to sensor application (three research articles and one review) and one research article dedicated to solid-phase extraction

Fabrication and Characterization of Hybrid Nanocomposites by Matrix Assisted Pulsed Laser Evaporation

Different methods have been applied to deposit hybrid nanocomposites which can be applied in various fields due to their light weight and multifunctional properties. Here, matrix assisted pulsed laser evaporation (MAPLE) equipment with 532 nm Nd:YAG laser is applied to fabricate three types of hybrid nanocomposites on different substrates. Chemical synthesized FeCo nanoparticles were deposited on graphene sheets by MAPLE technique (laser fluence: 300 mJ/cm2). The effects of deposition time (t) on particle amount, shape and size have been investigated. Yttrium barium copper oxide (YBCO) materials are one type of high-temperature superconductive materials and could be applied in transportation. To fabricate superconductive materials/graphene hybrid nanocomposites, YBCO nanoparticles were deposited on graphene sheets by MAPLE techniques with a laser fluence at 150 mJ/cm2. The microstructures in terms of particle size, size distribution, and particle shape are studied as functions of the deposition time (t). In addition, up-conversion nanoparticles (NaGdF4: Yb3+, Er3+) which are able to be excited by low energy photons (λex = 980 nm) and emit high energy photons were deposited through MAPLE technique. Results indicate that 2 hours’ deposition can result in high-quality samples in terms of particle size and particle amount. No toxic effect is imposed on the cells by the deposited up-conversion nanoparticles with/without protein modification. Our results indicate that the MAPLE deposition technique demonstrates the good versatility of depositing different nanoparticles and preserving their chemical composition

Proceedings of the Scientific-Practical Conference "Research and Development - 2016"

talent management; sensor arrays; automatic speech recognition; dry separation technology; oil production; oil waste; laser technolog

Polymer Processing and Surfaces

This book focuses on fundamental and applied research on polymer processing and its effect on the final surface as the optimization of polymer surface properties results in the unique applicability of these over other materials. The development and testing of the next generation of polymeric and composite materials is of particular interest. Special attention is given to polymer surface modification, external stimuli-responsive surfaces, coatings, adhesion, polymer and composites fatigue analysis, evaluation of the surface quality and microhardness, processing parameter optimization, characterization techniques, among others