Search

Tubular structures are critical components in infrastructure such as power plants. Throughout their life, they are subjected to extreme conditions or suffer from defects such as corrosion and cracks. Although regular inspection of these components is necessary, such inspection is limited by safety-related risks and limited access for human inspection. Robots can provide a solution for automatic inspection. The main challenge, however, lies in integrating sensors for nondestructive evaluation with robotic platforms. As part of developing a versatile lizard-inspired tube inspector robot, in this study the authors propose to integrate electromagnetic acoustic transducers into a modular robotic gripper for use in automated ultrasonic inspection. In particular, spiral coils with cylindrical magnets are integrated into a novel friction-based gripper to excite Lamb waves in thin cylindrical structures. To evaluate the performance of the integrated sensors, the gripper was attached to a robotic arm manipulator and tested on pipes of different outer diameters. Two sets of tests were carried out on both defect-free pipes and pipes with simulated defects, including surface partial cracking and corrosion. The inspection results indicated that transmitted and received signals could be acquired with an acceptable signal-to-noise ratio in the time domain. Moreover, the simulated defects could be successfully detected using the integrated robotic sensing system.

The article reports an innovative optical system that is designed to interrogate the health condition of macroscopically intact rail specimens by measuring its inherent nonlinearity using the narrowband Rayleigh waves. A line-arrayed pattern is developed through the optical system that generates narrowband Rayleigh waves with high power on the surface of the rail. As a result of lattice-anharmonicity, a second harmonic is produced in the wave that is sensed by a scanning laser Doppler vibrometer. The spectral amplitudes of the first and generated second harmonics are used to calculate the inherent nonlinearity using an amplitude-based nonlinearity equation. These measurements are carried out on the head, web, and foot of the rail. The performance of the non-contact experiment is also compared with that of a contact experiment carried out using wedge transducers. The experimentally evaluated nonlinearity of the rail steel is further compared with that obtained using a physics-based nonlinearity equation that relies on the higher-order elastic constants. Agreement of the results shows that the new optical system is effective in generating Rayleigh waves in rails and thereby measuring the inherent nonlinearity of the rail track. The estimation of inherent nonlinearity may help in diagnosing the health status of the macroscopically intact rail specimens in terms of their microstructural consistency and level of dissolved impurities before fixing them on a track.

Field Effect Transistor (FET)-based electrochemical biosensor is gaining a lot of interest due to its malleability with modern fabrication technology and the ease at which it can be integrated with modern digital electronics. To increase the sensitivity and response time of the FET-based biosensor, many semiconducting materials have been categorized, including 2 dimensional (2D) nanomaterials. These 2D materials are easy to fabricate, increase sensitivity due to the atomic layer, and are flexible for a range of biomolecule detection. Due to the atomic layer of 2D materials each device requires a supporting substrate to fabricate a biosensor. However, uneven morphology of supporting substrate leads to unreliable output from every device due to scattering effect. This review summarizes advances in 2D material-based electrochemical biosensors both in supporting and suspended configurations by using different atomic monolayer, and presents the challenges involved in supporting substrate-based 2D biosensors. In addition, we also point out the advantages of nanomaterials over bulk materials in the biosensor domain.

Lateritic bauxite are the products of intense subareal weathering of rocks. It is characterised by a particular enrichment of aluminium-hydroxide minerals such as gibbsite, boehmite and diaspore. Based on geological occurrences, bauxite is classified as lateritic, karstic, tikhvin type and about 86% deposits of the world are lateritic bauxite deposits. They typically are in stable areas of plateaux, where they had sufficient geological time to form and were protected from erosion. India is endowed about 3896 million tons of bauxite resources and Maharashtra state constitutes about 5 % of the total assets. The medium to high grade lateritic bauxite occurrences are located in western Maharashtra which spread up in two distinct belts, viz. high level and low-level coastal areas. The coastal bauxite deposits in Raigad, Ratnagiri and Sindhudurg districts are located at altitude varying between 50 to 350 m above mean sea level (msl), while high level bauxite deposits of Kolhapur, Satara and Sangli districts occur on the plateaus with an elevation 900 to 1300 m above msl. Most of the laterite of the western Maharashtra overlies the Deccan Trap basalt, except in some part of coastal areas, it either caps the Kaladgi sandstone or overlie the Dharwar pebble beds. The lateritic bauxite deposits of the western Maharashtra have been studied with reference to its geology, chemico-mineralogy and petrological characteristics. Field studies indicate the following successive stages developed during in-situ weathering: Deccan trap basalt (parent rock) → weathered basalt → saprolite/lithomargic clay → bauxite → duricrust (ferruginous, aluminous laterites). The geological, physical and chemico-mineralogical characteristics of the bauxite and laterite located in two belts is distinguished from one another. For the present study, two bauxite deposits namely Ringewadi and Velas located in Kolhapur (high-level) and Raigad (coastal) district of western Maharashtra respectively have been selected. The representative samples of bauxite, laterite, saprolite, parent rock have been collected. In present paper, comparative study has been done and the geological, geomorphological, geochemical, mineralogical, petrographic and physical characteristics of low level (coastal) and high-level lateritic bauxite deposits are highlighted.

The uneven morphology and the trapped charges at the surface of the traditionally used supporting substrate-based 2D biosensors produces a scattering phenomenon, which leads to irregular signal from individually fabricated device. Though suspended 2D channel material has the potential to overcome scattering effects from the substrates but achieving reliability and selectivity, have been limiting the biosensor technology. Here, we have demonstrated nanogap electrodes fabrication by using the self-assembly technique, which provides suspension to the 2D-MoS2. These nano-spacing electrodes not only give suspension but also provide robust strength to the atomic layer, which remains freestanding after coating of the Hafnium oxide (HfO2) as well as linkers and antibodies. For evaluating the electrical characteristics of suspended MoS2 FET, gating potential was applied through electrolyte on suspended MoS2 transistor, which achieved lower subthreshold swing 70 mV/dec and ON/OFF ratio 107. Afterward, pH detection has demonstrated at room temperature, which shows an impressive sensitivity of ∼880 by changing 1 unit of pH. Besides, we have successfully shown Escherichia coli (E. coli) bacteria sensing from suspended MoS2 transistor by functionalizing dielectric layer with E. coli antibodies. The reported biosensor has shown the ∼9% of conductance changes with a lower concentration of E. coli (10 CFU/mL; colony-forming unit per mL) as well as maintain the constant sensitivity in three fabricated devices. This type of the architecture has a potential to detect range of biomolecules such as COVID-19 viruses also by altering the oxide surface., Highlights • A suspended MoS2 atomic layer field-effect transistors is reported. • Self-assembled nanogap electrodes provide remarkable robust strength to the MoS2 atomic layer. • Suspended MoS2 field-effect transistor device exhibits impressive pH sensitivity and Escherichia coli bacteria detection. • The sensing mechanism highly selective to Escherichia coli bacteria.

The present study focuses on critical analysis of various aspects related to the evaluation of amplitude based material nonlinearity parameter γ amp through the numerical simulations and theoretical justifications. Two different materials with distinct nonlinearities are interrogated using Lamb waves in the numerical simulations. The effects of input force amplitude, number of cycles in the tone burst, tone burst windowing functions, material model parameters, excitation frequency, and wave propagation distance on γ amp are studied in detail. Also, γ amp estimated for the data obtained from the numerical simulations considering S 0 - S 0 mode pair at low frequencies and resonant S 1 - S 2 mode pair at higher frequencies are compared with the physics based material nonlinearity parameter γ phy . The difference between the results is marginal. Thus, the nonlinear Lamb wave technique can be effectively used even at low frequencies to estimate the actual material nonlinearity of the (metallic) plate materials with fair accuracy using the proposed nonlinearity models.

Continuously growing and miniaturizing autonomous electronic devices and sensors for large temperature window is mostly depends on stability and performance of power-up systems. The net achievable power and energy densities of such miniatured rechargeable energy storage systems are largely dominated by internal hardware and external packaging materials. Similarly, temperature stability of electrochemically active materials and packaging components is also crucial to realize desired activity at few millimeter scale devices. Herein, we explore energy storage devices at tunable miniatured scale by selecting optimal electroactive materials, thermally stable packaging components, and their fabrication process. Further, an assembled device is subjected to evaluate its energy and power density per foot-print-area along with other key electrochemical parameters such as internal resistance, self-discharge, and thermal stability. Detailed studies reveal that the presently packaged millimeter size rechargeable batteries (2 mm–5 mm) have the ability to work up to 120 °C with minimal load loss and compatible with energy harvesting renewable source of the solar cell.

Due to its unique electronic band characteristics (presence of d-orbital in both Mo and Se atoms), MoSe2 has potential to exhibit high electrical conductivity and superior hydrogen evolution reaction (HER) kinetics when compared to other transition-metal dichalcogenides. Though various strategies were employed earlier to obtain MoSe2 structure with different shapes and morphologies, precise control on achieving both Mo- and Se-edge sites and understanding their interaction with reactants in HER remains to be challenging. Here, we successfully demonstrate the vapor diffusion method to grow highly crystalline MoSe2 nanoflowers on carbon cloth in a vertical orientation. Uniformly dispersed nanoflowers with Mo- and Se-edge sites exhibited remarkable electrocatalytic activity on hydrogen reduction in terms of low Tafel slope and high exchange current density. The existence of a strong interaction between MoSe2 and carbon cloth assists in long-term hydrogen production and confirms the exceptional durability of the catalyst. A comprehensive evidence for hydrogen adsorption on dual active sites, viz., Mo- and Se-edges of MoSe2, is provided using X-ray photoelectron spectroscopy and in situ Raman spectroscopy containing a specially designed liquid immersion objective lens.

Previous studies carried out for quantifying the material nonlinearity of plate materials have used a nonlinearity parameter β which is derived for longitudinal waves. When Lamb waves are used as the probing waves, a relative nonlinearity parameter β ′ is used. This relative nonlinearity parameter β ′ is a non dimensionless parameter and gives the relative estimate of the material nonlinearity. In spite of these shortcomings, β ′ is widely used for quantifying the material nonlinearity using Lamb waves. Therefore, in the present study, firstly a physics based equation giving the nonlinearity parameter γ phy in terms of higher order elastic constants is derived considering the Lamb wave motion. The parameter γ phy gives an actual estimate of the material nonlinearity. This equation has its elastic component γ e resulting from the lattice anharmonicity and plastic component γ p resulting from the dislocations formed during fatigue or elastoplastic loading of the plate material. Secondly, a novel equation is derived to estimate the material nonlinearity γ amp , which uses the amplitudes of the fundamental harmonic and second harmonic of Lamb waves generated because of the material nonlinearity. With the help of this equation, the actual inherent material nonlinearity can be estimated and it can also be used to quantify the density of dislocations once the amplitudes of the fundamental and second harmonics of Lamb waves in a specimen are made available from the experiments or simulation. Therefore, this equation is practically useful. In order to validate the model, a literature based experimental verification is used here. In the first part, the inherent material nonlinearities of two different materials are estimated and values of β ′ and γ amp are compared qualitatively and quantitatively. In the second part, the density of dislocations is quantified using γ p as well as γ p / γ e . The agreement of results among γ amp and γ phy for virgin as well as plastically loaded specimens, confirms the validity of the proposed models.

We report a receiver using a single-polarization optical low-noise pre-amplifier and a burst-mode, time-gated clock recovery unit (CRU). Timing jitter and bit-error-ratio (BER) measurements are presented for data rates from 72 Mb/s to 2.880 Gb/s, both with and without atmospheric fading. At the lowest burst-mode data rate of 72 Mb/s, temporal gating improves the recovered clock’s timing jitter below receive power levels of −65 dBm, enabling comm-limited performance as opposed to CRU-limited performance. Gating extends the CRU and receiver range down to −88 dBm, a 3-dB sensitivity improvement over the non-gated case. For all data rates and channels measured, jitter values remain below 9 ps (3% of the clock period) with gating enabled. The BER performance is

This paper addresses the studies carried out on an I-beam to reveal the wave propagation characteristics and tackle the multi-mode propagation of Lamb waves. The experimental setup consisted of a new 3D Scanning Laser Doppler Vibrometer manufactured by Polytec (3D-SLDV) and was used to acquire high resolution time-space Lamb waves that were propagating in the I-beam. A high power and pulsed Nd:YAG laser was used to emit the required Lamb waves. The emission and sensing of the waves were carried out simultaneously. The wave propagation data was recorded by scanning the surface of the I-beam in a sequential manner. The measured data was used to construct the wave patterns that were propagating in the I-beams at different time instants. Furthermore, as the waves in an I-Beam propagate with multiple modes even at low frequency range, filtering was carried out in the frequency-wavenum- ber domain in order to decompose the modes. The results presented thereby confirm that the new 3D-SLDV possesses tremendous capability in revealing the wave propagation characteristics and its interaction with defect. The results could be the first time that the waves propagating in a real I-beam can be visually observed, whilst in the past, it can only be visualized through simulation. The capability of using such totally laser-based 3D inspection system to reveal the characteristics of Lamb wave and its interaction with defects are substantial.

Nowadays, false smut of rice, caused by Ustilaginoidea virens, is a disease of interest in the world. Presently, its traditional status as ‘minor disease’ has changed with widespread reports of severity from all the rice growing countries of the world. While many reports are available on the yield loss from the disease, little is known of its effect on grain quality. The present study is planned mainly to evaluate the effect of false smut disease on grain quality of different rice varieties from India. False smut had significant effect on yield (loss of 0.7–8.6%), cooking and nutritional qualities of many popular Indian varieties. Significant changes (p

The controlled introduction of impurities into the crystal lattice of solid-state compounds is a cornerstone of materials science. Intercalation, the insertion of guest atoms, ions or molecules between the atomic layers of a host structure, can produce novel electronic, magnetic and optical properties in many materials. Here we describe an intercalation compound in which the host [Co6Te8(PnPr3)6][C60]3, formed from the binary assembly of atomically precise molecular clusters, is a superatomic analogue of traditional layered atomic compounds. We find that tetracyanoethylene (TCNE) can be inserted into the superstructure through a single-crystal-to-single-crystal transformation. Using electronic absorption spectroscopy, electrical transport measurements and electronic structure calculations, we demonstrate that the intercalation is driven by the exchange of charge between the host [Co6Te8(PnPr3)6][C60]3 and the intercalant TCNE. These results show that intercalation is a powerful approach to manipulate the material properties of superatomic crystals. Intercalation — a cornerstone of materials science with wide-ranging applications — has now been demonstrated in a superatomic crystal. A redox-active tetracyanoethylene guest was inserted into the lattice of a material consisting of alternate layers of {Co6Te8} clusters and C60 fullerenes, leading to a single-crystal-to-single-crystal transformation that significantly modulates the material's optical and electrical transport properties.

In the present study, experiments are carried out on an Aluminium (Al) plate with and without damage, using Lamb waves and an array of four Piezoelectric Wafer (PW) transducers bonded onto it. The PW transducers are used to actuate and sense Lamb waves. These transducers are very compact, cheap, and can be easily bonded onto the structure. The responses recorded from the experiments, are further analyzed using a new algorithm developed by the authors, in order to localize the damage. The damage location is obtained as a small enclosed area formed by the intersection of various curves generated by an algorithm proposed by the authors. The damage location is further refined within this enclosed area using the optimization methods. Three different types of damages are considered in the present work. The case of multiple damage localization is also reported here. The results obtained by the algorithm are in excellent agreement with the actual location of damage. Thus, the present method has the capability of locating single as well as multiple damages in plate structures using minimal number of transducers.

Lithium-sulfur (Li-S) chemistry is projected to be one of the most promising for next-generation battery technology, and controlling the inherent "polysulfide shuttle" process has become a key research topic in the field. Regulating intermediary polysulfide dissolution by understanding the metamorphosis is essential for realizing stable and high-energy-density Li-S batteries. As of yet, a clear consensus on the basic surface/interfacial properties of the sulfur electrode has not been achieved, although the catalytic phenomenon has been shown to result in enhanced cell stability. Herein, we present evidence that the polysulfide shuttle in a Li-S battery can be stabilized by using electrocatalytic transition metal dichalcogenides (TMDs). Physicochemical transformations at the electrode/electrolyte interface of atomically thin monolayer/few-layer TMDs were elucidated using a combination of spectroscopic and microscopic analysis techniques. Preferential adsorption of higher order liquid polysulfides and subsequent conversion to lower order solid species in the form of dendrite-like structures on the edge sites of TMDs have been demonstrated. Further, detailed electrochemical properties such as activation energy, exchange current density, rate capabilities, cycle life, etc. have been investigated by synthesizing catalytically active nanostructured TMDs in bulk quantity using a liquid-based shear-exfoliation method. Unveiling a specific capacity of 590 mAh g

Protein subcellular localization of the human cell is an important step to analyze the distribution and functioning of proteins. Over the decades different sources have been utilized to gain insights into protein function. One of them is HTI (High Throughput Imaging) microscopy used by Human Protein Atlas(HPA). Anti-body staining techniques using fluorescent markers provide a high-resolution spatial visualization of proteins in human cells. HPA provides 4 channels for every image sample out of which green depicts protein distribution. This work is focused on localizing proteins into 14 distinct organelles in human cells. The task is to identify in which cell organelle are the protein present. Deep learning methods are validated for pattern recognition tasks in microscopy images. The architecture of Mobilenet is light-weight and results in reduced number of computation. The convolutional part of the network was used to extract image features while the top or fully connected layers of the model were replaced with a single softmax layer. Validation accuracy of 96% while a test accuracy of 91% was achieved.

The performance of devices from organic semiconductors is often governed by charge transfer phenomena at structurally and electronically complex interfaces, which remain challenging to access and study with excellent chemical and temporal resolution. Herein, we report the preparation and X-ray spectroscopic characterization of well-defined model organic-inorganic interfaces. We discover an unexpected trend for our systems' associated charge transfer times, and we rationalize this trend with density functional theory calculations. Our findings hold relevance for understanding interfacial charge transfer phenomena in a variety of organic, biological, and bioinspired systems.

Resistive chemical sensors were developed having as sensitive film graphene oxide (GO) spin-coated on glass. Sensor electrical behaviour to room temperature relative humidity was evaluated. High sensitivity characterizes GO sensor. However, it lacks repeatability and long term stability. To this end, we developed spin-coated GO sensors with different active layer thickness, which were subjected to subsequent thermal annealing steps. It was found that the resulting reduced GO (rGO) sensors demonstrate excellent stability compromising, though, the sensitivity which mainly depends on the number of annealing steps and film thickness. Finally, we propose a rapid, transparent, low-power consumption rGO sensor, enabling its use in relevant applications.

The focus of this study is on locating surface and sub-surface defects that occur in rail tracks using Rayleigh waves that were emitted and sensed by a fully non-contact laser transduction system. As the quality of received signals varies with respect to the rail surface characteristics, spotting the reflection from a defect can be extremely challenging. These signals are in general contaminated with noise and have low repeatability that could hinder the proper identification of the defect signal. In view of this, an innovative signal processing technique called a self-adaptive-smart algorithm (SASA) was designed and developed. In SASA, the incident wave that is the first coming wave-packet is taken as a mother wavelet. A library of possible mother wavelets was designed based on the experimental data. As the incident wave for each sensing point varies because of the physical condition of the rail surface and the laser excitation, the algorithm automatically picks the mother wavelet from the library that generates the largest absolute cross-correlation with the incident wave. SASA is found to be able to suppress the unwanted wave packets from the overall signal leaving behind only the incident wave for a healthy specimen, and the incident wave and its reflection from the defect for a damaged specimen. The functioning of the algorithm was successfully tested by carrying out extensive experiments on a real rail track in the presence of different types of surface and sub-surface defects on its head and web. The obtained results prove the effectiveness of using SASA in localizing defects in rails with a marginal error. Notably, the proposed method has benefits such as being self-adaptive, can help suppress high levels of noise, bring the peak of defect reflected wave in the center, and distinguish between a healthy and damaged sample.

We present a novel methodology to synthesize two-dimensional (2D) lateral heterostructures of graphene and MoS2 sheets with molecular carbon nanomembranes (CNMs), which is based on electron beam induced stitching. Monolayers of graphene and MoS2 were grown by chemical vapor deposition (CVD) on copper and SiO2 substrates, respectively, transferred onto gold/mica substrates and patterned by electron beam lithography or photolithography. Self-assembled monolayers (SAMs) of aromatic thiols were grown on the gold film in the areas where the 2D materials were not present. An irradiation with a low energy electron beam was employed to convert the SAMs into CNMs and simultaneously stitching the CNM edges to the edges of graphene and MoS2, therewith forming a heterogeneous but continuous film composed of two different materials. The formed lateral heterostructures possess a high mechanical stability, enabling their transfer from the gold substrate onto target substrates and even the preparation as freestanding sheets. We characterized the individual steps of this synthesis and the structure of the final heterostructures by complementary analytical techniques including optical microscopy, Raman spectroscopy, atomic force microscopy (AFM), helium ion microscopy (HIM), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) and find that they possess nearly atomically sharp boundaries.

The Letter presents a new design of Sagnac interferometer-based optical system (SIOS) that emits a line-arrayed pattern generating narrowband high-energy waves in a specimen. The SIOS is further used to excite Rayleigh waves in a pristine rail specimen to evaluate its intrinsic nonlinearity resulting from the lattice anharmonicity and dissolved impurities. Such a nonlinearity appears in the response in the form of a second harmonic that is sensed in this Letter using a scanning laser Doppler vibrometer. In addition to this noncontact measurement, a contact measurement of the nonlinearity of rail steel using wedge transducers is also carried out to compare the performance of the SIOS. Both experimentally evaluated nonlinearities are compared with those obtained using the nonlinear elasticity equations. The close agreement with the theoretically estimated nonlinearity and higher repeatability shows that the SIOS is effective in measuring the intrinsic nonlinearity of the rail steel and, thereby, predicting the health status of the rail specimens before fixing them on the track.

Overview Bottom-contact (BC) organic field-effect transistors (OFETs), though more industry-relevant than top-contact (TC) OFETs, are prone to low source-drain currents. The underlying mechanisms behind this remain debated. Thus, our work uses photocurrent microscopy (PCM) to examine charge injection in BC and TC geometries. PCM maps were generated first for OFETs with no electrode or gate dielectric treatments. Potential plots were quantitatively derived from the results using a method from previous work. [1] PCM maps were then collected for devices treated with 1. pentafluorobenzenethiol (PFBT), known to improve semiconductor morphology [2], and 2. UV-ozone, which is thought to enhance trap-assisted carrier transport. [3] These treatments were chosen, because they significantly increase source-drain current in BC devices, but in vastly different ways. In addition, unlike other photocurrent studies, we used a range of illumination wavelengths so as to probe various exciton states.

Ionizing radiation challenges the operation and reliability of electronic devices. While bulk devices have been well studied in the presence of ionizing radiation, there is limited information on the performance of 2D materials such as graphene in radiation harsh environments.1 Despite the expectation of a low radiation cross-section due to its single-atom thickness and low atomic number, prior work has shown that radiation has an effect on graphene-based devices, creating electrically active defects and degrading device performance.2 We demonstrate that a primary effect of gamma radiation on graphene field-effect transistors (GFETs) is degradation associated with activated atmospheric oxygen, and further improvement of device radiation hardness can be achieved by developing a charge shielded back-gated GFET architecture that protects against substrate charging effects. This represents a clear demonstration of radiation-hardened graphene devices.

Despite the massive success for high energy density, the charge–discharge current rate performance of the lithium-ion batteries are still a major concern owing to inherent sluggish Li-ion kinetics. Herein, we demonstrate three-dimensional porous electrodes engineered on highly conductive graphene current collectors to enhance the Li-ion conductivity, thereby c-rate performance. Such high-quality graphene provides surface area for loading a large amount of electrochemically active material and strong adhesion with the electrode. The synergism of porous structure and conductive current collector enables us to realize high-performance new-generation silicon anodes with a high energy density of 1.8 mAh cm−2. Further, silicon electrodes revealed with excellent current rates up to 5C with a capacity of 0.37 mAh cm−2 for 500 nm planar thickness.

We demonstrate permanent water trapping in reduced graphene oxide after high relative humidity exposure. For this purpose, we grew graphene oxide films via spin-coating on glass substrates followed by thermal reduction. The electrical resistance of the planar device was then measured. We observed that resistance is significantly increased after water vapor exposure and remains stable even after 250 days in ambient conditions. Various techniques were applied to desorb the water and decrease (recover) the material's resistance, but it was achieved only with low temperature thermal annealing (180 °C) under forming gas (H2/N2 mixture). The permanent effect of water absorption was also detected by x-ray photoelectron spectroscopy.

Electroactive polymer actuators such as polypyrrole (PPy) are exciting candidates to drive autonomous devices that require low weight and low power. A simple PPy tri-layer bending type cantilever which operates in the air has been demonstrated previously, but the environmental effect on this actuator is still unknown. The major obstacle in the development of the PPy tri-layer actuator is to create proper packaging that reduces oxidation of the electrolyte and maintains constant displacement. Here, we report the variation in the displacement as well as the charge transfer at the different environmental condition. PPy trilayer actuators were fabricated by depositing polypyrrole on gold-coated porous poly(vinylidene fluoride) (PVDF) using the electro-synthesis method. It has been demonstrated that the charge transfer of tri-layer actuators is more in an inert environment than in open air. In addition, tri-layer actuators show constant deflection and enhancement of life due to the negligible oxidation rate of the electrolyte in an inert environment.

Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. Here, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. We believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.