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The low cost, simplicity, and ease of use of paper microfluidic devices have made them valuable medical diagnostics for applications from pregnancy testing to COVID-19 screening. Meanwhile, the increasing complexity of paper-based microfluidic devices is driving the need to produce new tools and methodologies that enable more robust biological diagnostics and potential therapeutic applications. A new design framework is being used to facilitate both research and fabrication of paper-based microfluidic biological devices to accelerate the investigative process and reduce material utilization and manpower. In this work we present a methodology for this framework to dynamically place and route microfluidic components in a nondiscrete design space where fluid volume usage, surface area utilization, and the timing required to perform specified biological assays are accounted for and optimized while also accelerating the development of potentially lifesaving new devices.

This work reports the fabrication of integrated electrochemical fluidic paper-based analytical devices (ePADs) using a marker pen drawing and screen-printing. Electrodes were deposited on paper using screen-printing with conductive carbon ink. Then, the desired fluidic patterns were formed on the paper substrate by drawing with a commercial hydrophobic marker pen using an inexpensive computer-controlled x-y plotter. The working electrode was characterized by cyclic voltammetry and scanning electron microscopy. The analytical utility of the electrochemical PADs is demonstrated through electrochemical determination of Pb(II) and Cd(II) by anodic stripping voltammetry. For this purpose, the sample was mixed with a buffer solution and a Bi(III) solution, applied to the test zone of the PAD, the metals were preconcentrated as a bismuth alloy on the electrode surface and oxidized by applying an anodic potential scan. The proposed manufacturing approach enables the large-scale fabrication of fit-for-purpose disposable PADs at low cost which can be used for rapid on-site environmental monitoring.

Gas diffusion layer is one of the most important components of fuel cell, which supports the catalytic layer, collects the current and facilitates mass transfer. However, current carbon paper is mainly composed of long carbon fibers (CF), which brings drawbacks including rough surface, poor body homogeneity, excessive thickness, and preparation difficulty, etc. In this research, we invent a combination method to produce a highly flat, highly homogeneous, ultra-thin and high-performance carbon paper for proton exchange membrane fuel cell (PEMFC). The method combines the advantages of two materials, i.e. few-walled carbon nanotube (FWCNT) with high flatness and short CF with high porosity. And the combination method only contains three steps, material dispersion, carbon paper formation and heat treatment. The highest temperature for the heat treatment process is only 350 °C, which is much lower than the traditional 2000 °C. Due to the small size and fine distribution of FWCNT and CF, the new carbon paper exhibits highly flat (

L -dopa is a chiral drug that has been extensively used for the treatment of Parkinson’s disease. The concentration of L -dopa plays a vital role in the treatment, and this work emphasizes on designing a versatile platform for the quantitative and selective detection of L -dopa using reduced graphene quantum dot (rGQD). The platform is efficient in three different sensing methods, viz. fluorescence turn-on, filter paper-based sensing, and electronic measurements. The rGQD undergoes a dramatic fluorescence turn-on in the presence of L -dopa in aqueous media and artificial urine with a detection limit as low as 1.307 µM and 1.217 µM respectively. Experimental evidence revealed that the fluorescence enhancement is attributed to aggregation-induced emission mechanism. The system is also applicable for visual detection of L -dopa using filter paper strips treated with rGQD and develops bright fluorescence under ultra-violet irradiation. Apart from this, electrical sensors for L -dopa were also developed by preparing rGQD treated poly-vinyl alcohol films, and the increase in the current conduction with varying concentrations of L -dopa was observed. The films produce 2.5 order higher current conduction at 300 μM of L -dopa with a detection limit of about 13.136 µM. At the final stage, we have designed flexible electronic devices using these materials that develop 1.3 order higher current for L -dopa. The devices exhibit excellent air stability under varied relative humidity conditions as well as high bending stability for potential practical applications.

In recent era of modern and bendable technology, energy dearth arises as a paramount subject around the globe with a dire demand of flexible and lightweight energy storage devices. This study targets fabrication of reduced graphene oxide (rGO) and utility of abundantly available, cost effective, and environment friendly lignocelluloses (LC) fibers extracted from Carica papaya source, as a binder to bind active material (rGO) as robust and compact paper sheet. Fabricated samples were analyzed by X-ray diffraction for crystallographic analysis, Scanning electron microscopy, Transmission electron microscope for morphology, Fourier transform infrared spectroscopy for structural bonding, and Raman spectroscopy for vibrational modes. Robust and bendable rGO/LC paper electrode was tested for energy storage application by employing in different characterizations, i.e., cyclic voltammetry for capacitive behavior, galvanostatic charge–discharge for symmetric EDLC, and electrochemical impedance spectroscopy for resistive charge kinetics, respectively. rGO/LC composite sheet employed as working electrode in 3-electrode CV measurements and revealed specific capacitance of 591 F/g at a scan rate of 5 mV/s by keeping the undistorted shape of voltammograms at higher scan rates which present it as a suitable candidate for modern flexible and energy storage devices. rGO/LC-based symmetric cell revealed the highest specific capacitance of 228 F/g at applied current density of 0.1 A/g, the energy density of 6.3 Wh/kg, and power density of 129 W/kg, respectively. rGO/LC-based symmetric cell confirmed the cycling stability by revealing capacitance retention of 82% after 200 cycles. It can conclude that biomass-based rGO paper sheet can be a potential candidate as environmentally safe with remarkable electrochemical activity in energy storage applications.

Traction transformers are one of the most important equipment in the traction power supply system. Thermal aging of transformer insulation system determines its reliable life. To achieve an estimation of the insulation life of traction power transformers operated under real load condition, the effects of traction loads on the thermal aging of oil-paper insulation in traction transformers were investigated. First, the design principles for the accelerated thermal aging experiment were studied and proposed by considering magnitude (i.e., load rate) and frequency (i.e. spare time and lasting time) of the traction load. Then, an experimental system was established in the laboratory to conduct extensive accelerated thermal aging experiments, in which the traction loads were mimicked by using positive temperature coefficient (PTC) heating plates and a programmable logic controller (PLC). Finally, the experimental results were analyzed and discussed to reveal the effects of traction load on the thermal aging of oil-paper insulation in traction transformers.

In this study, the easy-to-operate silver mirror reaction (SMR) was used for metallizing chromatography paper. The SMR-metallized paper was characterized by water contact angle measurements, a surface profiler, x-ray photoelectron spectroscopy, UV–Vis spectroscopy, x-ray diffraction, and electrical resistance measurement. The characterization results show that Ag was successfully synthesized on cellulose fibers and was electrically conductive after cyclic bending. Moreover, this SMR-metallized paper was used as electrodes for fabricating a supercapacitor. This SMR-metallized paper could be used for realizing cost-effective flexible electronics applied in on-site biochemical sensing in resource-limited settings.

Made available in DSpace on 2022-04-29T08:36:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Paper electronics has emerged as an ecofriendly, light, low-cost, and recyclable material for the fabrication of flexible and printed transistors. In this study, we present fully printed organic electrochemical transistors using an active layer of PEDOT:PSS, carbon electrodes, cellulose-based electrolyte, and three different papers as substrates: bond, vegetal, and Lumi Silk, relating the electrical properties to the different morphologies of the paper surfaces. Each paper presents different regularity, diffusion capabilities, and roughness, with significant influence on the transistor performance. The more organized and smooth the surface, the better the electrical characteristics, the best of these being the Lumi Silk, with higher I on/I off ratio of 46, on-current of 8.3 10-5 A, V on of 1.3 V, and power gain of 43.5 dB associated with ultra-low hysteresis of 0.1 V, high transconductance of -57.3 μS, and suitablity for flexible electronics and sensors applications. S o Paulo State University - UNESP Faculty of Science and Technology (FCT) Physics Department, SP Universidade NOVA de Lisboa and CEMOP-UNINOVA Faculty of Science and Technology (FCT) CENIMAT/I3N Department of Materials Science S o Paulo State University - UNESP Faculty of Science and Technology (FCT) Physics Department, SP

Along with the unceasing growth of worldwide economic and the associated issues on resources, energy and environment, clean energy generating technologies that are based on recyclable materials, if possible, may become the future trend of development. Here, we report the design of a cheap, lightweight, and recyclable single-electrode triboelectric nanogenerator (TENG) that utilizes waste paper as the triboelectric material. Under the current strategy, we successfully developed green energy machines without vastly increasing the mining of various critical minerals around the world. The as-designed TENG could not only collect and convert mechanical energy into electricity with sound efficiency, but also has the merit for continuous reuse and quick construction. The maximum output power density is as high as 171 mW·m−2 at a resistance of 130 MΩ and could be integrated into a book for monitoring reading actions, thus providing a new approach to the low-cost, green and sustainable self-powered electronic systems.

The photon energy of terahertz waves is of the order of a few milli-electronvolts and is much lower than the thermal energy of ~ 26 meV at room temperature. However, the fast and sensitive detection of terahertz waves is notoriously difficult at ambient conditions. Moreover, the material flexibility is also very important within existing terahertz technologies for development of wearable and portable terahertz devices. We experimentally demonstrate that multiwall carbon nanotube flexible paper (MWCNT-FP) is one of the potential candidates to be used for terahertz detectors at room temperature. For the first time, MWCNT-FP sample is measured over a wide frequency band ranging from 0.02 to 4.5 THz at room temperature as compared to previously reported materials that demonstrate prominent frequency response between 0.2 and 2.5 THz. The MWCNT-FP sample delivered wide band absorption between 0.02 and 4.0 THz. Over the transmission, a high absorption peak is detected at 1.0 THz. The optical density spectrum is observed around 1.25 and 3.37 THz in the low-frequency regime and high-frequency regime, respectively. The present results suggest the potential application of MWCNT-FP as a wearable THz detector.

We present a rotational terahertz imaging system for inline nondestructive testing (NDT) of press sleeves for the paper industry during fabrication. Press sleeves often consist of polyurethane (PU) which is deposited by rotational molding on metal barrels and its outer surface mechanically processed in several milling steps afterwards. Due to a stabilizing polyester fiber mesh inlay, small defects can form on the sleeve’s backside already during the initial molding, however, they cannot be visually inspected until the whole production processes is completed. We have developed a fast-scanning frequenc-modulated continuous wave (FMCW) terahertz imaging system, which can be integrated into the manufacturing process to yield high resolution images of the press sleeves and therefore can help to visualize hidden structural defects at an early stage of fabrication. This can save valuable time and resources during the production process. Our terahertz system can record images at 0.3 and 0.5 THz and we achieve data acquisition rates of at least 20 kHz, exploiting the fast rotational speed of the barrels during production to yield sub-millimeter image resolution. The potential of automated defect recognition by a simple machine learning approach for anomaly detection is also demonstrated and discussed.

The papers in this special issue were submitted to all the conferences organized by IEEE Technology and Engineering Management Society (TEMS) in a given calendar year. In 2017, IEEE TEMS initiated its flagship conference TEMSCON (held in Silicon Valley), which serves as rebranding from its original International Technology Management Conferences (ITMC). Following that, in 2018, two more conferences were initiated globally, one in Asia known as IEEE TEMS International Symposium on Innovation and Entrepreneurship (ISIE), and one in Europe as IEEE TEMS International Conference on Technology and Entrepreneurship (ICTE). For this special issue, we invited authors attending any of the three aforementioned conferences in 2018 to submit full manuscripts for reviews, and the present special issue with eleven papers is the result of a careful selection following our usual rigid double-blinded peer-review process.

Valorisation involves conversion of toxic compounds into value added products. The present study has tried to evaluate the potential of vermicomposting in management of different types of toxic paper mill wastes such as primary waste (VCP) and secondary waste (VCS) using Eisenia fetida for 60 days. The procedure was performed using sundried samples of paper mill wastes, cow dung and straw in different trial sets using different ratios. The study had revealed that the trial sets (VCP1 and VCS1) using ratio of paper mill waste: Cow dung: Straw (5:4:1) were effective in maintaining physiochemical parameters and different population attributes of earthworm. The present study had also demonstrated the enzymatic enrichment of vermicompost in terms of 19 enzymes such as α-Glucosidase, lipase, leucine aminopeptidase etc. in maintenance of C/N ratio of the compost. A significant reduction of heavy metals were noticed in vermicomposting of primary waste (VCP1) as Zn (40%) ​> ​Pb (36%) ​> ​Cr (28%) ​> ​Cu (25%) and secondary waste (VCS1) as Zn (44%) ​> ​Pb (41%) ​> ​Cu (19%) ​> ​Cr (13%). Such reduction of heavy metal was highly correlated with the reduction of C/N ratio of the vermicompost. The process of bioremediation was further manifested through the regular monitoring of bioaccumulation factor (BAF) among earthworm population in vermicomposting of primary waste (VCP1) as Zn (0.40) ​> ​Cu (0.23) ​> ​Cr (0.18) ​> ​Pb (0.11) and secondary waste (VCS1) as Zn (0.47) ​> ​Cu (0.25) ​> ​Cr (0.21) ​> ​Pb (0.14). Therefore, the study concludes that the ratio of paper mill waste, cow dung and straw (5:4:1) can be an efficient formulation in qualitative enrichment of different toxic organic paper mill wastes through vermicomposting.

Flying insect detection, identification, and counting are the key components of agricultural pest management. Insect identification is also one of the most challenging tasks in agricultural image processing. With the aid of machine vision and machine learning, traditional (manual) identification and counting can be automated. To achieve this goal, a particular data acquisition device and an accurate insect recognition algorithm (model) is necessary. In this work, we propose a new embedded system-based insect trap with an OpenMV Cam H7 microcontroller board, which can be used anywhere in the field without any restrictions (AC power supply, WIFI coverage, human interaction, etc.). In addition, we also propose a deep learning-based insect-counting method where we offer solutions for problems such as the “lack of data” and “false insect detection”. By means of the proposed trap and insect-counting method, spraying (pest swarming) could then be accurately scheduled.

This work demonstrates the fabrication of tellurium-nanowires (Te-NWs)/paper based device encapsulated using laser assisted mircopyramid patterned polydimethylsiloxane (PDMS) films. Although there are multiple reports published on 1D Te, most of them are limited to establishing its properties and studying its behavior as a sensor and research on the utilization of Te-NWs for physical sensors remain unexplored. Further, reports on p-type photodetectors also remain scarce. The fabricated Te-NWs/paper with micropyramid structured PDMS films encapsulation was used as a strain sensor, and it exhibited considerable improvement (∼60%) in sensitivity compared to smooth PDMS films. The gauge factor of the developed strain sensor was found to be ∼15.3. In addition, fabricated Te-NWs/paper device with contacts was used as a photodetector and it showed photoresponsivity of ∼22.5 mA W-1and ∼14.5 mA W-1in visible and NIR regions, respectively. Furthermore, the device exhibited long-term mechanical stability under harsh deformations. Fabricated 1D Te-NWs/paper device was utilized as a strain sensor to monitor the angular movements in the human body and successfully monitored various human motions, including wrist bending, finger knuckle, elbow joint, and knee joint. The successful demonstration of Te-NWs based physical sensors and utilization in broadband photodetectors opens avenues of research for tellurium based flexible and wearable devices.

Under the dual pressure of energy consumption and environmental pollution, mankind hopes to develop clean and renewable alternative energy, and the rapid development of fuel cells meets people's demand for energy-efficient power systems. The emergence of portable micro energy systems represented by microfluidic fuel cells, such as paper-based microfluidic fuel cells, has greatly enriched the means of medical detection to better cope with the threat of disease transmission. In this work, the numerical simulation method is innovatively introduced to study the paper-based microfluidic fuel cells. Both transient and steady-state modes are employed to demonstrate the whole operation process of the paper-based microfluidic fuel cell. In addition, the different structural parameters, including electrode spacing, the distance between electrode and inlet, channel thickness, and electrode length, are also investigated their influence mechanisms on cell performance. Results show that the increase of most structural parameters decreases cell output power in different degrees. Even on the premise that increasing channel thickness has a positive impact on the output power, the fuel utilization still shows a downward trend. These conclusions provide theoretical support and reference for future optimization work and accelerate the development of microfluidic fuel cells.

The generated gas bubbles in microfluidic fuel cells (MFCs) cover the active surface area of the electrode and greatly limit the cell performance. In this study, a feasible approach is proposed to effectively accelerate bubbles removal and enhance cell performance by embedding a paper separator in the middle of the microchannel. Visualization of bubble behaviors and the corresponding electrochemical measurements are performed to investigate the effect of bubbles on the cell performance. Periodical process of the bubble growth and removal leads to the fluctuation in the current density of the MFC. The rapid gas removal and the low ohmic resistance are observed after embedding a layer of filter paper in the microchannel, causing improved fuel transfer and smaller ohmic loss. Although the current density fluctuates more frequently, the fluctuation amplitude decreases and the cell performance is enhanced. Compared with the MFC without paper separator, the maximum power density and the limiting current density of the MFC with paper separator is increased by 25.2% and 130%, respectively. Moreover, the cell performance is improved with increasing the flow rate of reactant solution and the peak power density achieves 25.9 mW cm−2 under flow rate of 1500 μL min−1.

I would like to introduce three wonderful papers to all our readers. Q. Xu and Y. Zhao from the Nanjing University of Aeronautics and Astronautics, China; X. Shen and K. Chen from the Nanjing Rongce Testing Technology Ltd, China; and Y. Huang from the University of Liverpool, U. K., authored the first paper "Absorption Cross Section Measurement of a Vehicle in Reverberation Chamber for Quick Estimation of Field Strength". For electromagnetic immunity testing of a vehicle, a reverberation chamber (RC) loaded with the vehicle-under-test has to be calibrated so that the necessary input power to generate the required field strength can be determined. In this paper, the average absorption cross section (ACS) of a vehicle in the frequency range of 80 MHz — 24 GHz is measured so that the required electric field strength in the RC loaded with a car can be estimated before the RC is constructed. Once the typical ACS of a car is known, one only needs to measure the Q factor of an unloaded RC and the Q factor of the RC loaded with a car can be predicted. This is very useful before the RC is constructed, as once the RC is built the unloaded Q factor cannot be increased.

In the present era of the Internet of Things (IoT) and sensor networks, clean and sustainable power sources are in huge demand, and triboelectric nanogenerators (TENGs) are a hot cake in green energy production. Here, we have developed a contact-separation mode TENG using liquid-phase exfoliated 2D-hexagonal boron nitride nanosheets (BNNSs) coated on biaxially-oriented polyethylene terephthalate (BoPET) and paper as counter triboelectric materials, which showed an impressive 70 times higher power output than simple BoPET-paper TENG assembly. Even under a moderate finger tapping force (~3 N), the developed BNNSs/BoPET-paper TENG device could generate an open circuit output voltage of ~200 V and a short circuit current density of ∼0.48 mA/m2. While under load testing, the peak value of electric power density for the BNNSs/BoPET-paper TENG device reached ~0.14 W/m2 at 200 MΩ resistive load. The incorporation of BNNSs has significantly enhanced the electron-accepting capabilities of the BoPET film which is evident from the enhanced dielectric permittivity of the BNNSs/BoPET assembly, and thus resulted in the enhanced electrical output of TENG. Additionally, the fabricated BNNSs-TENG was successfully demonstrated for powering electronic gadgets such as LCD clock, digital thermometer, and LEDs through cyclic finger tapping force.

To assess the aging of oil-paper insulation, an accelerated aging experiment is executed. Raman spectroscopy, a nondestructive detection method with access to component identification and fault diagnosis, is used to analyze the aging of oil-paper insulation. Raman feature of oil-paper insulation aging with a close relationship with the degree of polymerization is obtained based on the concept of quadratic mutual information. By analyzing the relationship between the extracted feature and the degree of polymerization of samples at different aging degrees, the feasibility of reflecting the aging degree of oil-paper insulation is determined. By load analysis, the chemical correlation between the extracted feature and oil-paper insulation aging is clarified. For eight test samples, the prediction error of degree of polymerization based on Raman features is less than 50. These results show that the features extracted in this paper are helpful to realizing the Raman spectrum diagnosis of oil-paper insulation aging.

Over the past few years, researchers have focused on stimulus-responsive soft materials and their applications in the design of soft actuators. The key factor of the soft actuators to achieve various applications is the programmable and controllable shape deformations. Here, a versatile and simple surface patterning method consisted of pencil drawing and pasting polymer films is proposed to design the soft actuators with programmable deformations. Due to the thermal expansion effect and the hygroexpansion effect, the graphite paper/polymer actuator performs a bending motion with a curvature of 1.4 cm−1 under light irradiation and 1.2 cm−1 under high humidity. Owing to the convenience of the patterning method, different patterns on both two surfaces of the paper substrate are designed without effort. Thus, through tuning the grayscale of the graphite on one surface of the paper, three types of T-shaped actuators can be obtained with different deformations under light irradiation. In addition, by pencil drawing or hydrophobically modifying specific patterns on the two surfaces of the paper, three types of strip-shaped actuators are also proposed to demonstrate that different 3D shape deformations can be obtained under different stimuli. Finally, a helix-shaped actuator inspired by the natural plant tendrils is fabricated by the thermal-induced shaping method. The helix-shaped actuator performs twisting/untwisting motion under different stimuli and can be used as a grasping robot. These results demonstrate the diversified programmability of the graphite paper/polymer actuator. Hence, the simple and versatile programming methods of soft actuators have great potential to be used in the field of biomimetic applications, intelligent robotics, and lab-on-paper devices.

The paper-based photodetector has recently captivated a great deal of attention in various opto-electronics applications because of facile, cost effective and green synthesis. Two-dimensional transition metal dichalcogenides materials are promising for photodetection under the broad spectral range. In this work, we have fabricated paper-based device by rubbing the tungsten di-selenide (WSe2) crystals on paper substrate. Low-cost, facile and green synthesis technique was employed to make a high-performance paper-based WSe2photodetector. Paper-based photodetector was fabricated via non-toxic simply rubbing process of WSe2nanosheets on low-cost bio-degradable paper. The photodetector shows good responsivity of 72.5 μA W-1and detectivity at around 2.4 × 107Jones at very low bias (1.0 V) at wavelength of 780 nm, respectively. Due to good photo-absorption strength, photodetector exhibits excellent photo-response over wide wavelength range from visible to near infrared. This device also shows very good flexibility with a stable photo-response. This device shows a general and reliable study for the design of photodetectors that is eco-friendly and cost-effective. Overall studied results of the fabricated device indicate that they have the ability to be used in large-scale preparation of the device.

It is generally accepted that the latest research findings are published as research papers in journals. Social network analysis (SNA) can offer a perspective from which to analyze technological developments. This work analyzes the development of lithium-ion batteries (LIBs) and electrolytes by SNA based on papers from 2011 to 2015. Three types of social networks, country-, institution-, and research paper-based networks were used. Country-based network analysis shows that major ten countries have a close relationship with respect to technology development. Institution-based network analysis revealed that 48 top institutions publish the most prolifically and that a “small-world” effect exists within the network, indicating excellent knowledge transfer among institutions through citations. Several institutions occupy the center position within the network and have a prominent influence in knowledge transfer as judged by centrality analysis. Research paper-based social networks, consisting of high-citation articles, are grouped into six technology clusters, which exhibit a broad range of knowledge transfer processes regardless of the battery and electrolyte types, indicating underlying closely interwoven relationships. The knowledge transfer path can describe the technology evolution in detail. An overview of technological development status can be thus obtained by this proposed three-level analysis method.

The optical model for reflectance lightness of stereo paper product surface is proposed, which could promote color reproduction study of paper model products and improving color reproduction quality. The reflectance lightness was measured using non-contact measurement method with spectroradiometer, CS2000A, that can measure stereo paper product surface lightness and tristimulus. Once inputting the paper product parameters of surface angle and tone, the model will predict the reflectance lightness for stereo paper product surface. After analyzing statistical information of light transmission, paper product surface reflectance lightness can be obtained. The results showed that prediction model is versatile and easy to use, besides the model quite approached to realistic paper product surface. The optical model simulation system could sufficiently accomplish reflectance lightness, which provides a novel way to predict and reproduce printing quality.

Creatinine is a clinically significant analyte used to diagnose kidney condition. However, the literature still lacks in creatinine sensors fulfilling point-of-care testing requirements. In this paper, we have developed colorimetric paper-based creatinine sensors adhering to point-of-care testing principles. The signal readout is accomplished with a smartphone modified with 3D-printed elements and processed with a self-written application compromising computer vision algorithm for automatic detection of the colored zone. Two colorimetric methods – routinely used Jaffe method and an alternative one with 3,5-dinitrobenzoic acid were both tested and compared. Hue channel intensity from HSV color space and green channel from RGB color space was used as the analytical signal in Jaffe and 3,5-dinitrobenzoate method, respectively. For both kinds of sensors the linear range of the response covered the range significant for urinary analysis, with precision, expressed as RSD, below 5%. Limit of quantification for Jaffe method was 1.05 mmol·L−1 whereas it was 0.82 mmol·L−1 for 3,5-dinitrobenzoate method. The utility of the developed sensors to selectively quantify creatinine in undiluted urine was proved using artificial urine samples and the obtained recoveries were in the range from 70 to 129 %.

Mercury (Hg) is a kind of the most common heavy metals with high toxicity in nature, existing in water, soil, and even food. Hence, it is of great importance to develop a simple, effective way to detect Hg2+. Flexible sensing has attracted extensive attention in recent years, which can be flexibly applied in various detection environments. Poly(3,4-ethylenedioxythiophene) (PEDOT) with conjugation structure which can accelerate the transfer of electrons and inhibit the recombination of carriers is favorable to the photoelectrochemical (PEC) process. Here, Br doped PEDOT modified carbon paper with narrower bandgap was firstly fabricated through situ thermal polymerization which exhibited high photocurrent intensity under visible-light irradiation. The success synthesis of PEDOT was confirmed by SEM, XPS, FT-IR and Raman spectrum. Meanwhile, the as-prepared electrode can be mass produced with good reproducibility. Based on excellent performance of as-prepared electrode of Br doped PEDOT/carbon paper, we constructed a PEC sensing platform for Hg2+ detection with the detection limit of 0.3 nM and linear range from 1 nM to 450 nM. In addition, the PEC sensor exhibited speedy response, outstanding stability, excellent selectivity, wide linear range, and was used for determination of Hg2+ in river water samples with recover range of 97.7–104.5 % and RSD of 2.8–4.7 %.

L-tyrosine hydroxylase (TH) is a critical enzyme and involved in the conversion of L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA) in the human body. TH deficiency is a rare autosomal recessive disorder which results in cerebral catecholamine deficiency and causes symptoms of depression, movement disorders, and impaired development. L-DOPA is the common precursor of catecholamine neurotransmitters, therefore how to rapidly and precisely determine the ratio of L-DOPA to L-tyrosine in the bio-matrix is important to the clinical diagnosis of disorder. To response the demand, a low-cost, user-friendly, and on-site detection system is developed herein, which includes a wax-printing paper microfluidics as reaction platform, surface modification with sodium periodate for improving detection performance, an additive manufactured enclosed case for maintaining identical detection environment, and an IOS application (APP) to drive smartphone’s imaging to facilitate high-throughput quantification of multiple biomarkers simultaneously. Multiple experiments were conducted to understand the detection limit, detection range, shelf-life, and specificity of this quantification system even with a complex bio-matrix such as artificial urine or Fetal Bovine Sera (FBS). The experiment results showed that L-DOPA, L-tyrosine, and creatinine can be easily and rapidly quantified with high reliability and repeatability, demonstrating an efficient tool for routine checkup of patients with TH deficiency.

The massless Dirac electron shows a linear energy dispersion in topological insulators (TIs) and these materials posses interesting properties such as high mobility, tuneable density and protection against backscattering over the time reversal symmetry and strong spin-orbit interaction. The flexibility is also an important parameter for development of wearable devices specially THz detector for imaging and quantum devices for optoelectronics applications. In this research work first time Bi2Te3 TIs thin film is fabricated on inhouse develop metallic multi wall carbon nanotubes flexible paper (MWCNT-FP) and characterized by terahertz-time domain spectroscopy acquired at room temperature. This research work delivers exclusive opportunities to explore interesting phenomena in topological surface states and topological phase transition in Bi2Te3 TIs thin film. Here, we measured terahertz absorption, optical density conductance and conductivity. An excellent broad band absorption is observed between 0.02 and 3.0 THz. The real conductance level is scientifically quite linear below 3.0 meV and thereafter certain increase. Similar trend is observed for the study of an imaginary conductance with respect to photon energy. The optical conductivity is observed in the range of 0.02–2.0 THz.

Our community publishes peer-reviewed journal, magazine, and conference papers and articles sharing a commitment to originality and to quality content and writing. These papers vary in their characteristics and style, depending on their objectives and their targeted readership. The IEEE Publication Services and Products Board (PSPB) Operations Manual (OM) also provides guidelines differentiating these paper types. There is confusion sometimes, however, concerning the features of magazine papers in particular. Some authors, especially early-career authors, do not fully appreciate certain differences between magazine papers and their journal, transaction, and letter counterparts. This can create a challenge for magazine editors and may result in delay, or rejection, of papers that could have been accepted if written with a better understanding of what magazines are about. We focus our attention here on this issue as it applies to IEEE Communications Magazine (ComMag) in particular. Our goal is to help our new and/or young authors who want to publish in ComMag to customize their writing to the nature of this magazine and enable them to author papers with higher chances of acceptance.

We are pleased to announce that the June 2022 issue of the IEEE Transactions on Dielectrics and Electrical Insulation (TDEI) will be a special issue on electrets and related phenomena. This issue is open to all authors. Presenters of papers at the IEEE 18th International Symposium on Electrets (ISE18) to be held during September 24–28, 2021 in Shanghai (China) are especially encouraged to submit their work to this special issue. For more information on ISE18 please go to https://ise18.tongji.edu.cn/.

Machine learning methods are being successfully applied in various domains of human activity, including optics. Can they become a universal instrument capable of improving user aspect of photonic devices? Is their application a necessary element of such improvement? Answers to fundamental questions arising from application of machine learning methods in ultrashort-pulsed lasers are discussed. Future prospects and current fundamental limitations of such methods are analysed.

Pulp writing materials made from wood-based origin and incorporating other fibers such as hemp waste, rags, and fishnets has been in existence since 105 CE when Cai Lun, a Chinese political official and inventor in the court of Emperor Hedi of Han, created the machinery and effective process of papermaking in China using the inner bark of the mulberry plant, hemp, rags from used clothing, and used fishnets. The mulberry bark was boiled down to create strands of fibers and macerated with hemp, rags, and fishnets to create the pulp used in processing the paper. Lun was assisted by his apprentice, Zuo Bo, who helped improve the overall process in 150 CE. Lun’s paper products superseded bamboo tablets and cloth made of pure silk as the primary writing material in China at that time [2] . The secret of papermaking was closely held by the Chinese until the sixth century, when the Japanese acquired the knowledge to produce their own paper. Then, by the eighth century, the Arab world began utilizing fine grades of hemp and linen with water to create pulp that they processed into a high grade of paper that was coated with rice starch when dried so it would be more receptive to inks. Unfortunately, the rice starch coating served also as a source of food for insects that destroyed many of the finished goods.

A noise-suppressing low-light image enhancement approach is proposed in this paper based on the extent of exposedness at each image pixel. To this end, a progressive, structure-aware exposedness estimation procedure is presented that quantifies local and global exposedness. These exposedness values are leveraged to produce a locally smooth pixel-level map that signifies the required degrees of enhancement at image pixels. This map is subsequently used in an enhancement function, which satisfies a few important properties, to generate the enhanced image. Before the enhancement, inherent noise in the low-light image is diminished employing a detail-preserving, low gradient magnitude suppression method. Subjective and quantitative analysis of results on a wide variety of natural and synthetically generated low-light images from standard databases using PSNR, iRSE, SSIM, and measures of perceptual quality, natural image statistics and brightness preservation suggests that our approach in general outperforms the state-of-the-art. Ablation studies and further experiments show the importance of a few components of our approach, and that our approach is computationally fast.

Autonomy of systems has been gaining increasing attention from scientists and engineers in various disciplines such as robotics, artificial intelligence, embedded systems, and control. However, there are serious challenges on the way of designing and adopting such systems, which haven’t, in our perspective, received sufficient attention yet. In this position paper, we review some of those challenges and present potential approaches of coping with them. Moreover, we highlight topics that require immediate attention and research efforts of the community. In particular, we propose three approaches: (i) More dependable autonomy using deterministic methods that can provide similar controllability, dependability, and traceability as that of traditional systems. Among such solutions is providing guarantee bands as opposed to guaranteed narrow operation points. (ii) Orthogonal autonomy adds autonomy in the extra-functional plane of the system. (iii) Expressive system design allows autonomous systems to trace and explain their decisions and reactions even though they may be using less deterministic tools.

Nowadays, due to modernization or advancement in the Internet of Things (IoT) especially in the Healthcare area, we want to take care of our elders with some monitoring equipment, and the Internet of Things can play a significant role in it. The motivation of writing this paper is to collect the information of various existing Internet of Things Architecture and Communication Techniques used in Healthcare Monitoring System to observe that how efficiently, different researchers have used it. So we have studied different real-time health monitoring system based on diseases which are common in elderly people like diabetes, blood pressure, heart disease, sleep apnea, and cancer, etc. In this real-time health monitoring system, researchers introduced many new measures, communication techniques like ZigBee, Long-Range Wide Area Network (LoRawan), Radio Frequency Identification (RFID). Apart from this, it was also observed that remote monitoring system in Healthcare is incomplete without data processing and early prediction in such diseases. Though, Machine learning provides efficient techniques to extract knowledge from diagnostic medical datasets collected from the patients. That is why we highlighted the current role of various Machine Learning algorithms like Support Vector Machine, K-Nearest Neighbor, Random Forest, etc., for processing of Healthcare data and also helpful to predict the output more precisely.

Introduction. This paper examines regulations which govern procedures for reporting incidents other than accidents or serious incidents related to unmanned aircraft system (UAS) operations. The regulations are discussed in the context of available data and the paper included an analysis of them from both a European and national perspective. The goal of the paper is to provide a series of recommendations with regard to the procedures for reporting and analyzing UAS incidents in order to improve the safe integration of unmanned and manned aviation. This article also explores the legal consequences that arise from the midair collision between a UAS and a manned aircraft. Material and methods: The method of study comprises a content analysis of existing legislations. The current doctrine was confronted with existing regulations, documents and materials. Results: The results of the study show that there is a practical problem of objectively identifying operators of a UAS as well as in defining what exactly constitutes an “incident”. It can be reasonably concluded that reporting and analyzing UAS-related incidents allows for the assessment and development of strategies for integrating manned and unmanned aviation. It is worth mentioning that drones and UAS technology requires refinement, especially in technological terms. It is reasonable to take action aimed at raising awareness amongst UAS users of the need to report incidents, as well as engaging UAS users in the investigative process which follows such occurrences.

Impedance matching and heat management are important factors influencing performance of THz sources. In this work we analyze thermal and radiative properties of such devices based on mesa structures of a layered high-temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. Two types of devices are considered, containing either a conventional large single crystal, or a whisker. We perform numerical simulations for various geometrical configurations and parameters and make a comparison with experimental data for the two types of devices. It is demonstrated that the structure and the geometry of both the superconductor and the electrodes are playing important roles. In crystal-based devices an overlap between the crystal and the electrode leads to appearance of a large parasitic capacitance, which shunts THz emission and prevents impedance matching with open space. The overlap is avoided in whisker-based devices. Furthermore, the whisker and the electrodes form a turnstile (crossed-dipole) antenna facilitating good impedance matching. This leads to more than an order of magnitude enhancement of the radiation power efficiency in whisker-based, compared to crystal-based devices. These results are in good agreement with presented experimental data., Comment: Presented at the 12 International Conference on Intrinsic Josephson Effect and Horizons of Superconducting Spintronics (22-25 Sept. 2021, Chisinau, Moldova)

Thermal oxidation of carbon electrodes is a common approach to improving flow battery performance. Here, we investigate how thermal pretreatment increases electrode surface area and the effect this...

Tin selenide (SnSe) has thermoelectric (TE) and photovoltaic (PV) applications due to its exceptional advantages, such as the remarkable figure of merit (ZT ≈ 2.6 at 923 K) and excellent optoelectronic properties. In addition, SnSe is nontoxic, inexpensive, and relatively abundant. These aspects make SnSe of great practical importance for the next generation of thermoelectric devices. Here, we report structural, optoelectronic, thermodynamic, and thermoelectric properties of the recently experimentally identified binary phase of tin monoselenide (π-SnSe) by using the density functional theory (DFT). Our DFT calculations reveal that π-SnSe features an optical bandgap of 1.41 eV and has an exceptionally large lattice constant (12.2 Å, P213). We report several thermodynamic, optical, and thermoelectric properties of this π-SnSe phase for the first time. Our finding shows that the π-SnSe alloy is exceptionally promising for the next generation of photovoltaic and thermoelectric devices at room and high temperatures.

The need to intensify the process of extracting sugar substances from sweet sorghum stalks in order to improve the quality and yield of the target product has been substantiated. Existing techniques of sugar substance extraction used in sweet sorghum processing technologies have been analyzed. The application of a combined technique for extracting sugary substances has been proposed implying the production of pressed and diffusion juice. The results of optimizing the press technique of juice extraction from sorghum stalks are given. The equations of material balance of products and sugars have been built, depending on such factors as the degree of pressing, the initial content of solids and sugars in the stalks. A procedure for calculating the yield of pressed juice, cake, and the content of total sugars has been devised, according to which the preliminary pressing of the stalks ensures the extraction of juice in the range of 25‒35%, the yield of the pressed cake is 75‒65% on average, with a sugar content exceeding 60%. It has been experimentally established that the use of the anti-current process of extraction of sugar substances from the pressed cake ensures their complete extraction from raw materials. The rational parameters for this process have been defined. At a temperature of 66–70°C and a duration of 20minutes, it is possible to obtain an extract whose content of solids is 13.0%, total sugars ‒ 11.10%, and whose purity is 85.38%. The research was carried out in order to intensify the extraction of sugar substances from sweet sorghum plant raw materials, to improve the technical level of the extraction process, and implement the devised method under industrial conditions. Further implementation of these results in the food industry could make it possible to establish the production of a wide range of sugar-containing products, both organically and as a natural substitute for sugar in food products.

The high-resolution scanning devices developed in recent decades provide biomedical volume datasets that support the study of molecular structure and drug design. Isosurface analysis is an important tool in these studies, and the key is to construct suitable description vectors to support subsequent tasks, such as classification and retrieval. Traditional methods based on handcrafted features are insufficient for dealing with complex structures, while deep learning-based approaches have high memory and computation costs when dealing directly with volume data. To address these problems, we propose IsoExplorer, an isosurface-driven framework for 3D shape analysis of biomedical volume data. We first extract isosurfaces from volume data and split them into individual 3D shapes according to their connectivity. Then, we utilize octree-based convolution to design a variational autoencoder model that learns the latent representations of the shape. Finally, these latent representations are used for low-dimensional isosurface representation and shape retrieval. We demonstrate the effectiveness and usefulness of IsoExplorer via isosurface similarity analysis, shape retrieval of real-world data, and comparison with existing methods. Graphic abstract