Showing papers by "Vipin Kumar published in 2017"

Highly Transparent, Stretchable, and Self-Healing Ionic-Skin Triboelectric Nanogenerators for Energy Harvesting and Touch Applications.

Abstract: Recently developed triboelectric nanogenerators (TENGs) act as a promising power source for self-powered electronic devices. However, the majority of TENGs are fabricated using metallic electrodes and cannot achieve high stretchability and transparency, simultaneously. Here, slime-based ionic conductors are used as transparent current-collecting layers of TENG, thus significantly enhancing their energy generation, stretchability, transparency, and instilling self-healing characteristics. This is the first demonstration of using an ionic conductor as the current collector in a mechanical energy harvester. The resulting ionic-skin TENG (IS-TENG) has a transparency of 92% transmittance, and its energy-harvesting performance is 12 times higher than that of the silver-based electronic current collectors. In addition, they are capable of enduring a uniaxial strain up to 700%, giving the highest performance compared to all other transparent and stretchable mechanical-energy harvesters. Additionally, this is the first demonstration of an autonomously self-healing TENG that can recover its performance even after 300 times of complete bifurcation. The IS-TENG represents the first prototype of a highly deformable and transparent power source that is able to autonomously self-heal quickly and repeatedly at room temperature, and thus can be used as a power supply for digital watches, touch sensors, artificial intelligence, and biointegrated electronics.

Carbon Coated Bimetallic Sulfide Hollow Nanocubes as Advanced Sodium Ion Battery Anode

Abstract: Sodium ion battery (SIB) as a next-generation battery has been drawing much attention due to the abundance and even distribution of sodium source Metal sulfides with high theoretical capacity and good electrical conductivity are promising anode candidates for SIB, however, the structural collapse caused by severe volume change during the de/sodiation process typically results in a fast capacity decay, limited rate capability, and cycling stability In this work, by careful composition and structure design, polydopamine coated Prussian blue analogs derived carbon coated bimetallic sulfide hollow nanocubes (PBCS) are prepared with distinguished morphology, higher surface area, smaller charge transfer resistance, and higher sodium diffusion coefficient than the uncoated bimetallic sulfides An optimum carbon coated bimetallic sulfide hollow nanocube anode delivers a specific capacity of ≈500 mA h g−1 at 50 mA g−1 with ethylene carbonate/dimethyl carbonate (1:1, vol%) electrolyte in the presence of fluoroethylene carbonate additives A capacity of 1223 mA h g−1 can be realized at 5000 mA g−1, showing good rate performance In addition the carbon coated bimetallic sulfide hollow nanocubes can maintain capacity of 87 mA h g−1 after being cycled at 500 mA g−1 for 150 times, indicating its good cycling stability The structure integrity, high specific capacity, good rate performance, and cycling stability of PBCS render it a promising anode material for advanced SIB

Self-powered pressure sensor for ultra-wide range pressure detection

Abstract: The next generation of sensors should be self-powered, maintenance-free, precise, and have wide-ranging sensing abilities. Despite extensive research and development in the field of pressure sensors, the sensitivity of most pressure sensors declines significantly at higher pressures, such that they are not able to detect a wide range of pressures with a uniformly high sensitivity. In this work, we demonstrate a single-electrode triboelectric pressure sensor, which can detect a wide range of pressures from 0.05 to 600 kPa with a high degree of sensitivity across the entire range by utilizing the synergistic effects of the piezoelectric polarization and triboelectric surface charges of self-polarized polyvinyldifluoride-trifluoroethylene (P(VDF-TrFE)) sponge. Taking into account both this wide pressure range and the sensitivity, this device exhibits the best performance relative to that of previously reported self-powered pressure sensors. This achievement facilitates wide-range pressure detection for a broad spectrum of applications, ranging from simple human touch, sensor networks, smart robotics, and sports applications, thus paving the way forward for the realization of next-generation sensing devices. Moreover, this work addresses the critical issue of saturation pressure in triboelectric nanogenerators and provides insights into the role of the surface charge on a piezoelectric polymer when used in a triboelectric nanogenerator.

Ti-Doped WO3 synthesized by a facile wet bath method for improved electrochromism

Abstract: Electrochromic materials could modulate the optical transmittance reversibly by the application of electric potential and the increase in the surface area for fast ionic diffusion is an efficient way to improve their electrochromism. In this work, WO3 based nanomaterials with a size as small as 5 nm were synthesized via a facile wet bath method that leads to Ti doping of WO3 based on the heterovalency of W(VI) and Ti(IV). Ti doping improved the WO3 electrochromism effectiveness in transmittance contrast and coloration efficiency due to the reduced crystallite size and therefore an increase in the surface area, the Ti doping also enhanced the cycling stability benefiting from the stable Ti–O bonding. However, the coloring/bleaching kinetics were deteriorated due to the reduced proton diffusion coefficient after the Ti ion substitution into the WO3 lattice. A high coloration efficiency of 106.6 cm2 C−1 and a good optical contrast of ∼67.6% can be obtained for the optimized Ti-doped WO3 at a wavelength of 633 nm.

Investigation of Charge Transfer Kinetics at Carbon/Hydroquinone Interfaces for Redox-Active-Electrolyte Supercapacitors

Abstract: The redox-active electrolyte supercapacitor (RAES) is a relatively new type of energy storage device. Simple addition of selected redox species in the electrolyte can greatly enhance the energy density of supercapacitors relative to traditional electric double layer capacitors (EDLCs) owing to redox reactions. Studies on the kinetics at the interface of the electrode and redox mediator are important when developing RAESs. In this work, we employ highly accurate scanning electrochemical microscopy (SECM) to extract the kinetic constants at carbon/hydroquinone interfaces. The charge transfer rate constants are 1.2 × 10-2 and 1.3 × 10-2 cm s-1 for the carbon nanotube/hydroquinone and reduced graphene oxide/hydroquinone interfaces, respectively. These values are higher than those obtained by the conventional cyclic voltammetry method, approximately by an order of magnitude. The evaluation of heterogeneous rate constants with SECM would be the cornerstone for understanding and developing high performance RAESs.

Study on optical investigations and DC conduction mechanism in polycrystalline chalcogenide (Cd, Zn) semiconductor films grown by screen-printing method

Abstract: The use of thin films of polycrystalline chalcogenide semiconductors has attracted much interest in an extensive variety of applications in various electronic, optoelectronic and photovoltaic devices due to their favorable electrical and optical properties. In this paper II–VI compound (cadmium and zinc chalcogenide) binary and ternary semiconductor thick films were deposited on ultraclean glass substrates by screen-printing method followed by sintering process. The polycrystalline nature of these films was confirmed by X-ray diffraction studies. The stoichiometry of the films was confirmed using energy dispersive X-ray analysis. The optical band gap and absorption coefficient of the films were determined by reflectance measurement in wave-length range 350–900 nm using UV/Vis spectrophotometer. The conduction mechanism in these films were studied by measuring the dark DC electrical conductivity in 300–400 K temperature range by using standard two probe method in vacuum. It was observed that conductivity of these films increases with increase in temperature. The linear nature of plot ln σDC against 1000/T for these films indicates that conductivity of films is in close agreement with the Arrhenius relation and conduction in these films is through thermally activated process.

Localized Charge Transfer in Two-Dimensional Molybdenum Trioxide

Abstract: Molybdenum trioxide is an interesting inorganic system in which the empty 4d states have potential to hold extra electrons and therefore can change states from insulating opaque (MoO3) to colored semimetallic (HxMoO3). Here, we characterize the local electrogeneration and charge transfer of the synthetic layered two-dimensional 2D MoO3-II (a polymorph of MoO3 and analogous to α-MoO3) in response to two different redox couples, i.e., [Ru(NH3)6]3+ and [Fe(CN)6]3– by scanning electrochemical microscopy (SECM). We identify the reduction of [Ru(NH3)6]3+ to [Ru(NH3)6]2+ at the microelectrode that leads to the reduction of MoO3-II to conducting blue-colored molybdenum bronze HxMoO3. It is recognized that the dominant conduction of the charges occurred preferentially at the edges active sites of the sheets, as edges of the sheets are found to be more conducting. This yields positive feedback current when approaching the microelectrode toward 2D MoO3-II-coated electrode. In contrast, the [Fe(CN)6]4–, which is redu...

Deposition and characterisation of spray-deposited nanocrystalline Cd1−XZnXS thin films for photovoltaic device applications

Abstract: Nanocrystalline Cd1−XZnXS thin films (X = 0.2, 0.4, 0.6, 0.8) have been grown on glass substrate by spray pyrolysis technique using equimolar concentration aqueous solution of cadmium chloride, zinc acetate and thiourea. Prepared thin films have been characterised by UV–vis spectrophotometer, X-ray diffractometer, SEM/EDAX analysis and two-point probe set-up. The optical band gap of the films has been studied by transmission spectra in wavelength range 325–600 nm. It has been observed that optical band gap increases with increasing zinc concentration. The X-ray diffraction pattern of films indicated that the films are polycrystalline with hexagonal grain structure. The lattice parameters of prepared Cd1−XZnXS films decrease with increase in zinc content. SEM/ EDAX analysis consolidates the formation of ternary compound. The DC electrical conductivity and activation energy of the films has been measured in vacuum by a two-point probe set-up. It has been observed that the electrical conductivity decreases w...

Effect of timing of vermicompost application and different level of NPK on growth, yield attributing characters and yield of rice in rice-wheat cropping system

Abstract: Two field experiments were conducted during 2011-12 and 2012-13 in the Crop Research Centre, of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh taking rice (PB-1) as a test crop. The maximum and significantly higher numbers of tillers per meter row length were recorded in T2 (100% NPK) followed by vermicompost with 75% N, 100% P and K before sowing. Maximum plant height was recorded with the application of 100% NPK. Recommended dose of NPK were significant in case of dry matter yield at maximum tillering and panicle initiation. Maximum grain yield during both the years was recorded with the application of 100% NPK (T2). Grain yield recorded under T2 differ significantly from T1, T9 and T10. Maximum straw yield was recorded in T2 followed by T1, T8, T9 and T10 during. Maximum biological yield found in T3.

Evaluation of Basmati Rice Varieties for Yield Performance and Economics under Farmers Field Situation in Muzaffarnagar District, India

Abstract: In district Muzaffarnagar rice is cultivated on 22302 ha area with average 25.07 qt/ha productivity. The basmati rice is known for its typical fragrance when cooked. They also fetch a premium price in the local and regional market, besides having considerable export potential. The basmati is promising foreign exchange earner (Singh et al., 1997). The fine grain, soft texture and extra elongation with least breadth-wise swelling on cooking endow ‘Basmati’ rice a special place in domestic and international market (Siddiqi, 1990). Basmati rice of Indian subcontinent is high priced in international market for its unique quality.

Management of black scurf disease of potato using chemicals Penflufen and Boric acid

Abstract: Black scurf (Rhizoctonia solani) diseases of potato are becoming prominent in many potatoes growing state resulting in economic losses, since a decade. An experiment was conducted to find out more effective management approaches through chemicals, taking cv. Kufri Bahar with five treatments involving chemicals i. e. Penflufen 240 F S and Boric acid, application before planting. Based on 2 years pooled data revealed that all the treatments were significant over control in terms of yield. Maximum total tuber yield was obtained from treatment T-3(27.69t/h) and minimum (24.03t/h) was in treatment T1(Control). However, minimum percent incidence of disease and disease severity at harvest was observed in treatment T-3(Tuber dip treatment with Penflufen (0.083 %) for 10 min. before planting) followed by treatment T-2 (Tuber dip treatment with Penflufen (0.062 %) for 10 min. before planting)

Distribution of weed flora of wheat under rice-wheat cropping system in Western Plain Zone of U.P

Abstract: The rice-wheat cropping system is the most important agricultural production system in western plain zone of U.P. A survey of weed flora of rice (Oryza sativa L.) and wheat (Triticum astivum L.) crop in rice-wheat cropping system under western plain zone of U.P. was conducted, during Kharif & Rabi season of 2015-16 and 2016-17. Echinochloa crus galli, Echinochloa colona, Asteracantha longifilia and Cyperus difformis were highly associated in rice crop in all the districts. Echinochloa crus galli and Echinochloa colona was most dominant weed in all the districts. The highest R.D. 19.67% was recorded with Echinochloa crus galli followed by other like Cynodon dactylon, Eclipa prostrate and Monochoria vanginalis some other weeds i.e. Cyperus iria were found in Bulandshahr, Meerut and Saharanpur. Chenopdodium album, Saccharum spontanium, Vicia sativa, Anagallis avensis, Fumaria parviflora, Cypresus rotundus, Cynodon dacetylam, Lathyrus aphaca, Carthamus oxycantha, Melilotus alba, Conovolvulus arvensis, Phalaris minor and Avena ludoviciana were found highly associated with wheat crop in all districts. Phalaris minor was the most dominant weed in all district the average the relative density 24.75% followed by other Lathyrus aphaca, Chenopdodium album, Fumaria parviflora some other weed like Saccharum spontanium found in Baghpat, Bulandhsahr, G.B. Nagar and Saharanpur having heavy soil in cultivated and non-cultivated land. Under very severe infestations of weeds, the losses may go up to 25 to 80%

Ab initio and DFT studies on structure, vibrational spectra of 4-tert-butyl-1,3-thiazol-2-amine (BTA)

Abstract: Theoretical studies have been carried out on 4-tert-butyl-1, 3-thiazol-2-amine (BTA) using both the B3LYP/6-311+G and HF/6-311+G methods. The geometrical parameters and vibrational spectra of BTA have been calculated and analyzed. The calculated IR wavenumbers have been compared with the observed FTIR wavenumbers. The complete assignments have been performed based on the potential energy distribution (PED) of the vibrational modes. The wavenumbers obtained from B3LYP method are in good agreement with the observed wavenumbers when compared to HF method. It has been found that there is an excellent correlation with 0.999 regression coefficient between the experiment and calculated vibrations. Thermal properties like rotational constants, zero point vibrational energies and nonlinear optical properties like dipole moment, hyperpolarizabilities, NBO analysis and the effect of temperature on various thermodynamic properties have been calculated and orted.

Determination of selection criteria with correlation and path coefficient analysis in chickpea (Cicer Arietinum L.) Breeding

Abstract: The experiment was conducted at College Farm, N. M. College of Agriculture, Navsari Agricultural University, Navsari, Gujarat, to estimate the selection criteria following correlation and path coefficient analysis in 50 genotypes of chickpea (Cicer arietinum L.). seed yield per plant was manifested positive and significant correlation with primary branches per plant, secondary branches per plant, plant height, number of pods per plant, number of seeds per pod, harvest index and 100 seed weight, indicated that these attributes were mainly influencing the seed yield in chickpea. The path analysis revealed that harvest index, secondary branches per plant, plant height, protein content, 100 seed weight and days to maturity affecting directly the seed yield per plant. Therefore, emphasis should be given to the development of chickpea lines with more number of primary and secondary branches per plant, more number of seed per pod, boldness and on high harvest index to improve seed yield per plant. Path analysis showed relatively high values of residual effect (0.721) indicating that there are other traits not recorded in the research, which may significantly be involved.

Nutrient content, uptake and quality of pearl millet influenced by phosphorus and zinc fertilization (Pennisetum galaucum L.) under rainfed condition

Abstract: A field experiment was carried out at the Agricultural Farm of Rajiv Gandhi South Campus, Banaras Hindu University, Barkachha, Mirzapur to study the effect of phosphorus and zinc application on nutrient content, uptake and quality of pearl millet. On the basis of experimental data significant improvements were recorded in nutrient (N, P K and Zn ) content, uptake and quality of pearl millet. Nutrient N, P and K content in grain and straw significantly increased from 1.56 to 2.02, 0.773 to 1.320, 1.10 to 1.97 % and 1.11 to 1.41, 0.23 to 0.50 and 0.68 to 1.20 %, respectively. The lowest N, P and K content in grain and straw was recorded in control. The maximum N, P and K content in grain (2.02, 1.320 and 1.97 %) and straw (1.11, 0.23 and 0.68 %) was recorded with application of 30 kg P ha-1 + 20 kg Zn ha-1. The similarly results were found in uptake of N, P and K by grain and straw in pearl millet. Zn content in grain and straw ranged between 23.43 to 52.32 and 24.88 to 58.46 ppm and the lowest value (23.43 and 24.88 ppm) was recorded in control. The highest Zn content in grain and straw was recorded in the treatment 10 kg P ha-1 + 30 kg Zn ha-1. Zn uptake in grain and straw varied between 374.92 to 937.90 and 810.86 to 2109.86 g ha-1, respectively. The maximum uptake of Zn in grain and straw was recorded in 10 kg P ha-1 + 30 kg Zn ha-1, which was increased by 60 and 62 % over control. The combined effect of phosphorus x zinc were found significant for N & K content and uptake by grain and straw and protein content in grain.

Management of black scurf disease of potato in Rajasthan

Abstract: Black scurf (Rhizoctonia solani) diseases of potato are becoming prominent in many potatoes growing state resulting in economic losses, since a decade. An experiment was conducted to find out more effective management approache through chemicals, taking cv. Kufri Bahar with five treatments involving chemicals i. e. Pencycuron (Moncern) and Boric acid, application before storage alone. Minimum disease incidence (17.25) and tuber yield (26.11 t/ha) was noticed in Tuber spray treatment with Pencycuron 22.9% (Moncern) @ 0.50 before planting alone followed by Tuber dip treatment with 3% boric acid or 10 min. before planting. These treatments can provide an effective management of potato tuber diseases

Direct and residual effect of Zinc and FYM on quality and uptake of N, P, and K in pearl millet-wheat cropping system

Abstract: Different doses of Zinc (kg/hectare) and FYM (ton/hectare) were applied in pearl millet-wheat sequence to assess the uptake of Nitrogen, Phosphorus and Potassium in two consecutive years. The maximum values of nitrogen content in pearl millet grain and stover was recorded at 7.5 kg Zn + 5 t FYM/ha treatment in both crop seasons. The maximum values of N content in wheat grain and straw were recorded under 5 t FYM/ha + 10 kg Zn/ha treatment in both crop seasons. Application of 5t FYM/ha increased the P content in grain and stover over control in both the years. The phosphorus content in crop was further improved with combined application of FYM and zinc. The maximum values of P content in pearl millet grain and stover were recorded under 5 t FYM/ha + 5 kg Zn/ha whereas in case of wheat it was at 5 t FYM/ha + 7.5 kg Zn/ha. in both crop seasons. The various levels of zinc in combination with 5 t FYM/ha resulted in significantly higher uptake of K in the crop in both crop seasons over zinc alone. The highest uptake of K (15.5 kg/ha in grain and 189*.7 kg/ha in stover) was recorded under 5 t FYM/ha + 7.5 kg Zn/ha treatment in pearl millet. The effect of this combination was found to be statistically at par with 5 t FYM/ha+ 5 kg Zn/ha treatment. In case of wheat the uptake of Potassium almost similar pattern was observed at 5 kg Zn + 5 t FYM/ha and 7.5 kg Zn + 5 t FYM/ha doses. The direct applications of Zn along with FYM and its residual amount improved the yields of pearl millet and wheat as well as uptake of Nitrogen, Phosphors and Potassium in both crops.