Swift heavy ion irradiation effect on Cu-doped CdS nanocrystals embedded in PMMA

Semiconductor nanocrystals (NCs) have received much interest for their optical and electronic properties. When these NCs dispersed in polymer matrix, brightness of the light emission is enhanced due to their quantum dot size. The CdCuS NCs have been synthesized by chemical route method and then dispersed in PMMA matrix. These nanocomposite polymer films were irradiated by swift heavy ion (SHI) (100 MeV, Si⁺⁷ ions beam) at different fluences of 1 × 10¹⁰ and 1 × 10¹² ions/cm² and then compared their structural and optical properties by XRD, atomic force microscopy, photoluminescence, and UV-Vis spectroscopy before and after irradiation. The XRD spectra showed a broad hump around 2θ ≈ 11·83° due to amorphous PMMA and other peaks corresponding to hexagonal structure of CdS nanocrystals in PMMA matrix. The photoluminescence spectra shows a broad peak at 530 nm corresponding to green emission due to Cu impurities in CdS. The UV-Vis measurement showed red shift in optical absorption and bandgap changed from 4·38–3·60 eV as the irradiation fluency increased with respect to pristine CdCuS nanocomposite polymer film.     

Accumulation of chromium and zinc from aqueous solutions using water hyacinth (Eichhornia crassipes)

Under present investigation Eichhornia crassipes (water hyacinth) has been tested for removal of two important heavy metals chromium (Cr) and zinc (Zn) from metal solution. This species was grown at four concentrations of Cr and Zn, i.e. 1.0, 5.0, 10.0 and 20.0 mg l(-1) in single metal solution. This plant has performed extremely well in removing the Cr and Zn from their solution and was capable of removing up to 95% of zinc and 84% of chromium during 11 days incubation period. Removal of Cr at lower concentrations (1.0 and 5.0 mg l(-1)) was found harmless, without any symptom of toxicity but at 10.0 and 20.0 mg l(-1), plants have shown some morphological symptoms of toxicity. On the other hand E. crassipes removed Zn safely at all the four concentrations, i.e. 1.0, 5.0, 10.0 and 20.0 mg l(-1). In this case morphological symptoms of toxicity were not evident in the test plant. Biochemical parameters viz. protein, sugar and chlorophyll in experimental plants have shown a decreasing trend due to accumulation of Zn and Cr. Overall this methodology is safe for the removal of Zn and Cr and can be utilized at large scale after few further investigation.     

Investigations on the photocatalytic activity of sol–gel derived plain and Fe/Nb-doped titania coatings on glass substrates

Plain and doped (Fe³⁺ and Nb⁵⁺) titania coatings were deposited by dip coating on soda lime glass substrates using titania sol synthesized by sol–gel route in combination with commercial nanoparticle dispersions. The dopant concentrations were fixed at 0.07 wt% and the coatings heat treated at 400 °C were characterized with respect to their thickness, phase composition, hydrophilicity/hydrophobicity and microstructure. Photocatalytic activity testing was carried out on the coatings by following up the degradation of methylene blue dye for up to 4 h at 1 h time intervals after exposure to sunlight. The effect of a trivalent and pentavalent doping of Ti⁴⁺ sites on photocatalytic activity of TiO₂ was investigated.     

Distribution, enrichment and principal component analysis for possible sources of naturally occurring and anthropogenic radionuclides in the agricultural soil of Punjab state, India

Enrichment factor (EF) of elements including geo-accumulation indices for soil quality and principal component analysis (PCA) were used to identify the contributions of the origin of sources in the studied area. Results of (40)K, (137)Cs, (238)U and (232)Th including their decay series isotopes in the agricultural soil of Mansa and Bathinda districts in the state of Punjab were presented and discussed. The measured mean radioactivity concentrations for (238)U, (232)Th and (40)K in the agricultural soil of the studied area differed from nationwide average crustal abundances by 51, 17 and 43 %, respectively. The sequence of the EFs of radionuclides in soil from the greatest to the least was found to be (238)U > (40)K > (226)Ra > (137)Cs > (232)Th > (228)Ra. Even though the enrichment of naturally occurring radionuclides was found to be higher, they remained to be in I(geo) class of '0', indicating that the soil is uncontaminated with respect to these radionuclides. Among non-metals, N showed the highest EF and belonged to I(geo) class of '2', indicating that soil is moderately contaminated due to intrusion of fertiliser. The resulting data set of elemental contents in soil was also interpreted by PCA, which facilitates identification of the different groups of correlated elements. The levels of the (40)K, (238)U and (232)Th radionuclides showed a significant positive correlation with each other, suggesting a similar origin of their geochemical sources and identical behaviour during transport in the soil system.     

Blue shift in optical band gap of sol–gel derived Sn1−xZnxO2 polycrystalline thin films

Undoped and Zn doped SnO₂ thin films are deposited by sol–gel spin coating on glass substrate. XRD spectra with prominent peaks along (110) and (101) planes shows the polycrystalline nature of thin films. The particle size lies between 9.30 and 42.09 nm as estimated by Debye–Scherer method. SEM micrographs of the films contain pebble like structures spread throughout whose diameter decreases with increase in dopant concentration. Surface topology of the films is studied by atomic force microscopy. Transmission spectra show that all the films are highly transparent in the visible and IR spectral region (80–90 %) and a sharp absorption occurs near 300 nm. Approximately a change of 4 % is observed in the optical band gap by Zn doping. The optical band gap is tunable between 3.55 and 3.68 eV for 0 ≤ x ≤ 0.15 in nanocrystalline Sn_1?xZn_xO₂. Broad UV emission at 395 nm is observed in photoluminescence spectra of the films along with a blue emission. Emission intensity decreases as amount of Zn incorporated into SnO₂ increases.     

Biological Data Analysis Program (BDAP): a multitasking biological sequence analysis program

Neural Computing and Applications - Exploration of mysterious facts from the sequences and structures of biomolecules of an organism is the essential requirement for understanding their molecular...     

Correction to: Year based EM-index: a new approach to evaluate the scientific impact of scholars

Scientometrics - In the original publication, Acknowledgements was published with incomplete information. The complete Acknowledgements is given in the correction.     

Year based EM-index: a new approach to evaluate the scientific impact of scholars

Scientometrics - In the research community, generally the assessment of scholarly impact of an individual is based on citation counts of publications. Instead of this a different approach, year...     

Effectiveness evaluation of passive resistive element placement on a fault ride‐through enhancement in a DFIG‐based wind energy conversion system

Over the last few decades, doubly fed induction generators (DFIG) have become one of the most successful and preferred types of wind energy generators (WEG). The DFIG has the advantages of a wide range of speed operations, a high efficiency, and partial rated converters. However, direct coupling of the stator with the grid makes the system more prone to grid disturbances. The consequences of grid disturbances, such as a rotor overcurrent, stator overcurrent, electromagnetic torque oscillations, and direct current (DC) link overvoltage, are the predominant considerations that affect the rotor circuit, stator circuit, mechanical components, and DC‐link capacitor of the DFIG, respectively. These uncertainties affect the operation of the generator and may lead to the generator to be shutdown. In this paper, a novel position for the placement of a passive resistive element (PRE) is illustrated. This position of the PRE placement is compared with all other possible locations for the PRE. The different locations for PRE placement are the stator side, rotor side, across the DC‐link capacitor, and between the rotor side converter (RSC) and grid side converter (GSC). This paper aims to determine a cost‐effective solution among all possible locations of the PRE placement. The novel position of the PRE, ie, between the RSC and GSC, is the best position among the other possible locations of the PRE, when the performance, cost, and loss are taken into consideration. The effectiveness of the PRE is further compared with the resistive‐type superconducting fault current limiter (R‐SFCL). The PRE performs better and has a lower cost than the R‐SFCL.     

Recent advancements in lateral flow immunoassays: A journey for toxin detection in food

Biotechnology embraces various physical and chemical phenomena toward advancement of health diagnostics. Toward such advancement, detection of toxins plays an important role. Toxins produce severe health impacts on consumption with high mortality associated in acute cases. The most prominent route of infection and intoxication is through food matrices. Therefore, rapid detection of toxins at low concentrations is the need of modern diagnostics. Lateral flow immunoassays are one of the emergent and popularly used rapid detection technology developed for detecting various kinds of analytes. This review thus focuses on recent advancements in lateral flow immunoassays for detecting different toxins in agricultural food. Appropriate emphasis was given on how the labels, recognition elements, or detection strategy has laid an impact on improvement in immunochromatographic assays for toxins. The paper also discusses the gradual change in sensitivities and specificities of assays in accordance with the method of food processing used. The review concludes with the major challenges faced by this technology and provides an outlook and insight of ideas to improve it in the future.