Herein, we demonstrate the fabrication of highly capacitive activated carbon (AC) using a bio-waste Kusha grass (
Desmostachya bipinnata
), by employing a chemical process followed by activation ...through KOH. The as-synthesized few-layered activated carbon has been confirmed through X-ray powder diffraction, transmission electron microscopy, and Raman spectroscopy techniques. The chemical environment of the as-prepared sample has been accessed through FTIR and UV–visible spectroscopy. The surface area and porosity of the as-synthesized material have been accessed through the Brunauer–Emmett–Teller method. All the electrochemical measurements have been performed through cyclic voltammetry and galvanometric charging/discharging (GCD) method, but primarily, we focus on GCD due to the accuracy of the technique. Moreover, the as-synthesized AC material shows a maximum specific capacitance as 218 F g
−1
in the potential window ranging from − 0.35 to + 0.45 V. Also, the AC exhibits an excellent energy density of ~ 19.3 Wh kg
−1
and power density of ~ 277.92 W kg
−1
, respectively, in the same operating potential window. It has also shown very good capacitance retention capability even after 5000th cycles. The fabricated supercapacitor shows a good energy density and power density, respectively, and good retention in capacitance at remarkably higher charging/discharging rates with excellent cycling stability. Henceforth, bio-waste Kusha grass-derived activated carbon (DP-AC) shows good promise and can be applied in supercapacitor applications due to its outstanding electrochemical properties. Herein, we envision that our results illustrate a simple and innovative approach to synthesize a bio-waste Kusha grass-derived activated carbon (DP-AC) as an emerging supercapacitor electrode material and widen its practical application in electrochemical energy storage fields.
Label-free and sensitive detection of PSA (Prostate Specific Antigen) is still a big challenge in the arena of prostate cancer diagnosis in males. We present a comparative study for label-free PSA ...aptasensor and PSA immunosensor for the PSA-specific monoclonal antibody, based on graphene quantum dots-gold nanorods (GQDs-AuNRs) modified screen-printed electrodes. GQDs-AuNRs composite has been synthesized and used as an electro-active material, which shows fast electron transfer and catalytic property. Aptamer or anti-PSA has immobilized onto the surface of modified screen printed electrodes. Three techniques are used simultaneously, viz. cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedence spectroscopy (EIS) to investigate the analytical performance of both PSA aptasensor and PSA immunosensor with its corresponding PSA antigen. Under optimum conditions, both sensors show comparable results with an almost same limit of detection (LOD) of 0.14 ng mL
. The results developed with aptasensor and anti-PSA is also checked through the detection of PSA in real samples with acceptable results. Our study suggests some advantages of aptasensor in terms of better stability, simplicity and cost effectiveness. Further our present work shows enormous potential of our developed sensors for real application using voltammetric and EIS techniques simultaneous to get reliable detection of the disease.
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•A highly efficient Ca doped Eu: Y2O3 (CEY) nanophosphor material has been synthesized through a facile combustion method.•It has been used as a simple and selective turn-off ...fluorescence probe for the quantitative analysis of iron ions (Fe3+).•The proposed probe allows the quantification of iron in the range of 10 µM–90 µM with a limit of detection (LOD) ∼ 63.2 nM under the natural pH range.•The applicability of the sensor as an efficient probe has been investigated with real water samples, iron tablets, and human blood serum (HBS).•Furthermore, it does not require any acidic medium for a level-free, and non-enzymic detection of a real sample with almost not affecting the sample quality and henceforth provides more reliable results.
The present work reports a highly efficient Ca doped Eu: Y2O3 i.e Ca0.05Eu0.01Y1.94O3 (CEY.) nanophosphor material synthesized through a facile combustion method, as a simple and selective turn-off fluorescence probe for the quantitative analysis of iron ions (Fe3+). The proposed sensor allows the quantification of iron in the range of 10 µM–90 µM with a limit of detection (LOD) ∼ 63.2 nM under the natural pH range. Moreover, CEY nanophosphor shows an excellent fluorescence phenomenon with a gradual increase in the Fe3+ ion concentration. It has been observed that the corresponding PL intensity gets completely quenched with 500 µM Fe3+ ion concentration. Furthermore, the applicability of the sensor as an efficient probe has been investigated with real water samples, iron tablets, and human blood serum (HBS). The selectivity of the probe has also been analyzed with various metal ions and biomolecules. Thus, in turn, the as-obtained sensing probe illustrates an excellent accuracy, sensitivity, and selectivity, and offers potential application in clinical diagnosis, biological and real water sample studies, with the detection of Fe3+ ion. Furthermore, it does not require any acidic medium for a level-free, and non-enzymic detection of a real sample with almost not affecting the sample quality and henceforth provides more reliable results.
Abstract
In this study, the effect of irradiation temperature on microstructural evolution of Indian RPV steel is reported. This study, by virtue of helium ion irradiation at 77, 300 and 573 K, could ...bring out the effect of the irradiation induced defects on microstructural and mechanical property changes at different stages of their existence starting from the state of cascade damage till the point of their free migration. Irradiation experiments were performed with varying ion energies to achieve nearly uniform irradiation damage of 0.05, 0.2 and 3 dpa in a ~ 300 nm wide region. Irradiated samples were characterized using GIXRD, PAS, TEM and nanoindentation. Unirradiated samples showed predominant presence of a combination of di- and tri-vacancy type of defects. Most of the dislocations present in unirradiated samples were screw dislocations, while mixed type was noticed upon irradiation irrespective of the irradiation temperature. PAS study showed formation of distinct defect types at different irradiation temperatures. TEM study confirmed formation of dislocation loops and defect clusters on irradiation. Higher irradiation temperatures resulted in the extension of the width of the damage region owing to increased migration of defects.
Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a ...need to increase areal storage densities beyond ~1 Tb/in
. This requires the thickness of carbon overcoats (COCs) to be <2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in
areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media.
To understand the effect of nitrogen doping in hard carbon as anode for sodium ion battery, experimental and theoretical study have been done. To also see the size effect along with nitrogen doping, ...four varieties of carbon spheres are synthesized of two different size ranges viz. micron and nano-sized. Two of these spheres are nitrogen-doped, while the other two are un-doped. Nitrogen doping enhances the electrochemical performance of carbon spheres and increases the active storage sites by enhancing the number of defects and porosity. It further improves electrochemical performance by increasing electrical conductivity and controlling volume expansion. The density functional theory (DFT) study shows significant reduction in expansion associated with sodiation, i.e., from 21.7% to 7.9% because of nitrogen doping. After nitrogen doping, micron and nano-sized carbon spheres show an increase in capacity by 38.6% and 39.5%, respectively. Among these four electrodes, nitrogen-doped nano carbon spheres (NNCS) give the best performance. NNCS shows first reversible capacity of 286 mAh g−1, retains 85% of the capacity till 200 cycles at a current density of 30 mAg−1. This increase in electrical conductivity, defects, porosity, and reduction in volume expansion in nitrogen-doped carbon samples makes them an excellent material for sodium ion batteries.
•Size control and nitrogen doping of hard carbon.•Reduction in volume expansion during sodiation.•Improved electrical conductivity and porosity.•Improved specific capacity, cycle life and rate capability of hard carbon.
Some new kind of azetidinone derivatives of benzotriazole 5a–i synthesized from N-(benzylidene hydrazino)-propyl-benzotriazole 4a–i. The reaction was carried out by both conventional and microwave ...methods. Some azetidinone derivatives of benzotriazole displayed better antitubercular and antimicrobial activity.
We report herein the synthesis and biological activity of a new kind of azetidinone derivatives of benzotriazole. The reaction was carried out by both conventional and microwave methods. The chemical structures of all the synthesized compounds were deduced according to FTIR, 1H NMR, 13C NMR and FAB-mass spectral along with microanalytical data. All the synthesized compounds of series 5a–i were evaluated for their antitubercular activity against Mycobacterium tuberculosis H37RV and antimicrobial activity against some selected microorganism. Unexpectedly, some azetidinone derivatives of benzotriazole displayed better activities.
Chitosan is one of the important natural bio-polymers. Besides its good green value, it is rarely used to protect metals in aggressive media in direct form due to rapid degradation of its molecules ...in acid. Hence, it is necessary to use some means to increase protection efficiency of chitosan. In present work, cobalt and tin sulfide nanoparticles are used to synthesize chitosan-cobalt and chitosan-SnS2 nanocomposites, and used for corrosion protection of mild steel (MS) in 1 M HCl at room temperature. The prepared composites are investigated by UV–visible spectroscopy, FTIR spectroscopy, HRSEM, HRTEM and EDAX techniques, which have shown successful formation of nanocomposites. Corrosion behavior of the composites have been examined by Tafel polarization curves (TPC), single sine electrochemical impedance spectroscopy (SSEIS) and surface analyzing techniques. The results have declared that chitosan-cobalt nanocomposite is more effective in corrosion inhibition of mild steel than chitosan-SnS2 nanocomposite. Alone chitosan provide only 77% inhibition to mild steel, while it increases for chitosan‑cobalt (>95%) and chitosan-SnS2 (>80%) composites. Isotherm study suggests that adsorption of chitosan/composites over MS is main reason of inhibition and can be best defined with Frumkin isotherm. Adsorption of chitosan and chitosan-nanocomposites over MS is also evident by SEM and AFM.
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The efficient (site-specific) management of soil nutrients is possible by understanding the spatial variability in distribution of phyto-available nutrients (here after called available nutrients) ...and identifying the soil management zones (MZs) of agricultural landscapes. There is need for delineating soil MZs of agricultural landscapes of the world for efficient management of soil nutrients in order to obtain sustainability in crop yield. The present study was, therefore, undertaken to understand the spatial distribution pattern of available micronutrients (zinc (Zn), boron (B), iron (Fe), manganese (Mn) and copper (Cu)), available sulphur (S), and soil properties (soil acidity (pH), electrical conductivity (EC) and organic carbon (SOC) content) in soils of intensively cultivated Indo-Gangetic Plain (IGP) of India and to delineate soil MZs for efficient management of soil nutrients. Totally, 55101 soil samples from 0-15 cm depth were obtained from 167 districts of IGP during 2014 to 2017 and were analysed for different soil parameters. Soil pH, EC and SOC content varied from 4.44 to 9.80, 0.02 to 2.13 dS m.sup.-1 and 0.10 to 1.99%, respectively. The concentration of available Zn, B, Fe, Mn, Cu and S varied from 0.01 to 3.27, 0.01 to 3.51, 0.19 to 55.7, 0.05 to 49.0, 0.01 to 5.29 and 1.01 to 108 mg kg.sup.-1, respectively. Geostatistical analysis resulted in varied distribution pattern of studied soil parameters with moderate to strong spatial dependence. The extent (% area) of nutrient deficiencies in IGP followed the order: S > Zn > B > Mn > Cu > Fe. Principal component analysis and fuzzy c-means clustering produced six distinctly different soil MZs of IGP for implementation of zone-specific soil nutrient management strategies for attaining sustainability in crop yield. The developed MZ maps could also be utilized for prioritization and rationalization of nutrients supply in IGP of India.
The emergence of computationally powerful smartphones, relatively affordable high-resolution camera, drones, and robotic sensors have ushered in a new age of advanced sensible monitoring tools. The ...present review article investigates the burgeoning smartphone-based sensing paradigms, including surface plasmon resonance (SPR) biosensors, electrochemical biosensors, colorimetric biosensors, and other innovations for modern healthcare. Despite the significant advancements, there are still scarcity of commercially available smart biosensors and hence need to accelerate the rates of technology transfer, application, and user acceptability. The application/necessity of smartphone-based biosensors for Point of Care (POC) testing, such as prognosis, self-diagnosis, monitoring, and treatment selection, have brought remarkable innovations which eventually eliminate sample transportation, sample processing time, and result in rapid findings. Additionally, it articulates recent advances in various smartphone-based multiplexed bio sensors as affordable and portable sensing platforms for point-of-care devices, together with statistics for point-of-care health monitoring and their prospective commercial viability.
Figure: A graphical representation of present review article. Display omitted
•POC detection programmes are widely utilized throughout the entire world due to their user-friendly characteristics.•Real-time monitoring of health metrics is made possible by smartphones that come with a variety of sensors and apps.•Smartphone-based POC devices have great potential for environmental analysis, food safety analysis, and disease diagnosis.
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