Carrier transport and photoconductivity properties of BN50/NiO50 nanocomposite films.

BN50/NiO50 and Au-loaded BN50/NiO50 nanocomposite films were separately fabricated on the glass substrates for carrier transport and photoconductivity properties. X-ray diffraction pattern of the films show the hexagonal structure of BN and presence of defect states by Nelson Riley factor analysis. Morphological images show spherical shaped particles with highly porous structure. The incorporation of NiO may hindered growth of BN layers and resulted in spherical particles. Temperature-dependent conductivity describes semiconductor transport behaviour for deposited nanocomposite films. Thermal activation conduction with low activation energy (∼0.308 eV) may be responsible for the resulting conductivity. Further, the light intensity dependent photoelectrical properties of BN50/NiO50 and Au-loaded BN50/NiO50 nanocomposites have been explored. The effect of Au nanoparticles loading on enhanced photo-conductivities (∼22% increase) than bare nanocomposite film has been elaborated by proposed mechanism. This study provided the insightful information for carrier transport and photoconductivity of BN-based nanocomposites.

Enhanced Oxidation Resistance of Ultrafine-Grain Microstructure AlCoCrFeNi High Entropy Alloy.

This work investigates the effect of ultrafine-grain microstructure on the oxidation behavior of AlCoCrFeNi high entropy alloy (HEA). The ultrafine-grain microstructure is obtained using stationary friction processing performed at two different rotational speeds, 400 and 1800 rpm, for 5 min duration. Processed samples demonstrate high depth of refinement (DOR) and ultrafine grain size (0.43-1 µm) at high rotational speeds along with significant phase transformations from BCC/B2 to FCC microstructure. Further, surface free energy of the ultrafine-grain microstructure is enhanced up to 35%. Oxidation kinetics of the ultrafine-grained sample is decelerated up to 12-48% in a temperature range of 850-1050 °C for a duration of 100 h. Chromia and alumina were the predominant oxides formed in almost all the samples oxidized at elevated temperature. In addition, spinel Co(Cr,Fe)2O4/Fe(Co,Cr)2O4 formation is also detected in the unprocessed oxidized samples. Processed samples rich in grain boundaries (GBs) promote internal oxidation to form Al-rich inner oxides. The enhanced oxidation resistance of the processed samples is attributed to the microstructural refinement and homogenization resulting in the formation of protective chromia followed by Al-rich inner oxides.

An investigation on dissimilarity of mass flow rate and N on exergo-enviro-economic parameters for solar still of single slope type integrated with N similar PVT flat plate collectors having series connection.

This paper investigates analytically the effect of dissimilarity of mass flow rate [Formula: see text] and number of collectors (N) on exergo-enviro-economic parameters for solar still of single slope type integrated with N similar photovoltaic thermal flat plate collectors having series connection (NPVTFPC-SS) keeping water depth as 0.14 m. All four kinds of weather conditions for New Delhi have been taken for the computation of different parameters. All relevant equations obtained using energy balance equations for all components of the system have been fed to a computer code inscribed in MATLAB-2015a for computing different parameters. The computation of different relevant parameters has been performed for various values of [Formula: see text] and N while keeping water depth as constant to know the effect of variation of [Formula: see text] and N on exergo-enviro-economic parameters for NPVTFPC-SS. It has been concluded that the value of carbon credit earned, enviroeconomic and exegoeconomic parameters, and productivity diminishes with the enhancement in [Formula: see text] at given N. The optimum value of N for given value of [Formula: see text] has been found to be 10 from exergoeconomic parameter viewpoint and 6 from productivity viewpoint.

Review on performance assessment of solar stills using computational fluid dynamics (CFD).

Environmental pollution and water resource management are some of the biggest challenges for the twenty-first century. The utilization of solar energy for water purification through solar stills is an environmental friendly and sustainable approach. Computational fluid dynamics (CFD) is a valuable and cost-effective tool for the simulation of fluid and thermal phenomena in solar stills as well as for their optimization for maximum productivity. The objective of the current study is to present a comprehensive review of the significance of the CFD tool in analysis, performance estimation, and design improvements of solar still. Various studies in this direction are classified according to the comprehensiveness of the modeling approach employed. The approaches are classified into three categories. The assumptions and governing equations for various approaches are presented. It is highlighted that the relatively simpler CFD modeling of only the humid air zone in the solar still, which relies on the availability of experimental data, the modeling approach has now evolved to an advanced level and can give predictive estimates by using only the ambient atmospheric conditions and solar irradiation as input. Various studies are also classified based on configurations, computational domain, and operational and geometrical parametric range. The key results from various CFD studies are summarized.

Structural, diffuse reflectance and luminescence study of t-Mg2B2O5 nanostructures.

We report here the structural, reflectance, photoluminescence and thermoluminescence study of t-Mg2B2O5 nanostructures synthesized using optimized combustion method relatively at much lower temperature. The rietveld refinement of X-ray diffraction data confirms single-phase triclinic crystal structure of Mg2B2O5 nanoparticles. The direct band gap determined using diffuse reflectance spectra (DRS) was 5.23 eV, which is contrary to earlier reports quoting Mg2B2O5 as indirect band gap material. To elucidate the nature of band gap in Mg2B2O5, we performed first principle calculations based on full potential linearized augmented plane-wave (FPLAPW) method, predicting the direct band gap of 5.10 eV in t-Mg2B2O5 which is in good agreement with our experimental results. The t-Mg2B2O5 nanoparticles were found to exhibit yellow-reddish photoluminescence peaking at 588 nm, attributed to various defects states. The combustion synthesized Mg2B2O5 nanocrystals exhibited ultraviolet (254 nm) responsive thermoluminescence (TL). TL glow curve of Mg2B2O5 comprises of one dominant peak around 417-428 K and less intense shoulder around 573-589 K which arouse possibility of various trapping sites or defects present in the sample. The TL analysis using general order Kitti's equations was performed to estimate the activation energies of trapping states. Owing to already well-known mechanical and thermal properties, the direct wide band gap nature and UV responsive thermoluminescence of combustion synthesized t-Mg2B2O5 nanostructures can pave way for its use in luminescence-based applications and UV dosimetry. As an additional application of Mg2B2O5, anti-biofilms activity of Mg2B2O5 nanoparticles using pseudomonas aeruginosa bacterial cells was also performed which revealed 91 ± 2.7% inhibition of biofilms formed by P. aeruginosa, respectively, at 100 µg/ml after 24 h of treatment.

Genome-Wide Transcriptional Profiling to Elucidate Key Candidates Involved in Bud Burst and Rattling Growth in a Subtropical Bamboo (Dendrocalamus hamiltonii).

Bamboo, one of the fastest growing plants, can be a promising model system to understand growth. The study provides an insight into the complex interplay between environmental signaling and cellular machineries governing initiation and persistence of growth in a subtropical bamboo (Dendrocalamus hamiltonii). Phenological and spatio-temporal transcriptome analysis of rhizome and shoot during the major vegetative developmental transitions of D. hamiltonii was performed to dissect factors governing growth. Our work signifies the role of environmental cues, predominantly rainfall, decreasing day length, and high humidity for activating dormant bud to produce new shoot, possibly through complex molecular interactions among phosphatidylinositol, calcium signaling pathways, phytohormones, circadian rhythm, and humidity responses. We found the coordinated regulation of auxin, cytokinin, brassinosteroid signaling and cell cycle modulators; facilitating cell proliferation, cell expansion, and cell wall biogenesis supporting persistent growth of emerging shoot. Putative master regulators among these candidates were identified using predetermined Arabidopsis thaliana protein-protein interaction network. We got clues that the growth signaling begins far back in rhizome even before it emerges out as new shoot. Putative growth candidates identified in our study can serve in devising strategies to engineer bamboos and timber trees with enhanced growth and biomass potentials.

Next Generation Sequencing Technologies: The Doorway to the Unexplored Genomics of Non-Model Plants.

Non-model plants i.e., the species which have one or all of the characters such as long life cycle, difficulty to grow in the laboratory or poor fecundity, have been schemed out of sequencing projects earlier, due to high running cost of Sanger sequencing. Consequently, the information about their genomics and key biological processes are inadequate. However, the advent of fast and cost effective next generation sequencing (NGS) platforms in the recent past has enabled the unearthing of certain characteristic gene structures unique to these species. It has also aided in gaining insight about mechanisms underlying processes of gene expression and secondary metabolism as well as facilitated development of genomic resources for diversity characterization, evolutionary analysis and marker assisted breeding even without prior availability of genomic sequence information. In this review we explore how different Next Gen Sequencing platforms, as well as recent advances in NGS based high throughput genotyping technologies are rewarding efforts on de-novo whole genome/transcriptome sequencing, development of genome wide sequence based markers resources for improvement of non-model crops that are less costly than phenotyping.

Amplified fragment length polymorphism of clinical and environmental Vibrio cholerae from a freshwater environment in a cholera-endemic area, India.

BACKGROUND: The region around Chandigarh in India has witnessed a resurgence of cholera. However, isolation of V. cholerae O1 from the environment is infrequent. Therefore, to study whether environmental nonO1-nonO139 isolates, which are native to the aquatic ecosystem, act as precursors for pathogenic O1 strains, their virulence potential and evolutionary relatedness was checked. METHODS: V. cholerae was isolated from clinical cases of cholera and from water and plankton samples collected from freshwater bodies and cholera-affected areas. PCR analysis for the ctxA, ctxB, tcpA, toxT and toxR genes and AFLP with six primer combinations was performed on 52 isolates (13 clinical, 34 environmental and 5 reference strains). RESULTS: All clinical and 3 environmental isolates belonged to serogroup O1 and remaining 31 environmental V. cholerae were nonO1-nonO139. Serogroup O1 isolates were ctxA, tcpA (ElTor), ctxB (Classical), toxR and toxT positive. NonO1-nonO139 isolates possessed toxR, but lacked ctxA and ctxB; only one isolate was positive for toxT and tcpA. Using AFLP, 2.08% of the V. cholerae genome was interrogated. Dendrogram analysis showed one large heterogeneous clade (n = 41), with two compact and distinct subclades (1a and 1b), and six small mono-phyletic groups. Although V. cholerae O1 isolates formed a distinct compact subclade, they were not clonal. A clinical O1 strain clustered with the nonO1-nonO139 isolates; one strain exhibited 70% similarity to the Classical control strain, and all O1 strains possessed an ElTor variant-specific fragment identified with primer ECMT. Few nonO1-nonO139 isolates from widely separated geographical locations intermingled together. Three environmental O1 isolates exhibited similar profiles to clinical O1 isolates. CONCLUSION: In a unique study from freshwater environs of a cholera-endemic area in India over a narrow time frame, environmental V. cholerae population was found to be highly heterogeneous, diverse and devoid of major virulence genes. O1 and nonO1-nonO139 isolates showed distinct lineages. Clinical isolates were not clonal but were closely related, indicating accumulation of genetic differences over a short time span. Though, environment plays an important role in the spread of cholera, the possibility of an origin of pathogenic O1 strains from environmental nonO1-nonO139 strains seems to be remote in our region.