222 research outputs found
Re-awakening of GRS 1716–249 after 23 yr, observed by Swift/XRT and NuSTAR
In this work, we present a spectral and temporal analysis of Swift/XRT and NuSTAR observations of GRS 1716–249 during its recent 2016–2017 outburst. This low-mass X-ray binary underwent an extraordinary outburst after a long quiescence of 23 yr, since its last major outburst in 1993. The source was observed over two different epochs during 2017 April 7 and 10. The best-fitting joint spectral fitting in the energy range 0.5–79.0 keV indicates that the spectrum is best described by relatively cold, weak disc blackbody emission, dominant thermal Comptonization emission, and a relativistically broadened fluorescent iron K α emission line. We observed a clear indication of a Compton hump around 30 keV. We also detected an excess feature of 1.3 keV. Assuming a lamp-post geometry of the corona, we constrained the inner disc radius for both observations to 11.92^(+8.62)_(−11.92) R_(ISCO) (i.e. an upper limit) and 10.39^(+9.51)_(−3.02) R_(ISCO)(where R_(ISCO) ≡ radius of the innermost stable circular orbit) for the first epoch (E1) and second epoch (E2), respectively. A significant (5σ) type C quasi-periodic oscillation (QPO) at 1.20 ± 0.04 Hz is detected for the first time for GRS 1716–249, which drifts to 1.55 ± 0.04 Hz (6σ) at the end of the second observation. The derived spectral and temporal properties show a positive correlation between the QPO frequency and the photon index
Achievability of Municipal Solid Waste Compost for Tea Cultivation with Special Reference to Cadmium
Not AvailableMunicipal solid waste compost (MSWC) is quite often used for soil amendment in agricultural crops and yet little is known about its effect on tea (Camellia sinensis L.) cultivation. This study investigates the effect of MSWC application on cadmium (Cd) concentrations in soil, tea plants, and infusions. Different doses of MSWC are added to soil with two Tocklai vegetative (TV) tea clones (TV1 and TV23) for 2 years in pot experiments. Several fractions of Cd in amended soils, biomass yield, and Cd content in different parts of tea plants and in tea infusions are measured. Several indexes related to risk assessment are also calculated. The geo‐accumulation index values of Cd in soil amended with MSWC ranges from −1.74 to 3.12, indicating class 0 (practically uncontaminated) to class 4 (heavily contaminated) contamination level. Average daily intakes (ADI) of Cd through tea infusion produced from tea plant amended with MSWC are 8.9 × 10−6 and 9.2 × 10−6 mg kg−1 per body weight and day for men and women, respectively. These values are much lower than those given in the Joint FAO/WHO Provisional Tolerable Monthly Intake Guideline for Cd. The non‐carcinogenic risk values (also called hazard quotient) for Cd, estimated from the ADI values, are found to be 1.78 × 10−2 and 1.94 × 10−2 mg kg−1 per day for men and women, respectively, suggesting no health hazard. The results suggested the possibility of management of MSW through composting and the feasibility of compost application for tea cultivation.Not Availabl
Vanadium Dioxide Cathodes for High-Rate Photo-Rechargeable Zinc-Ion Batteries
Photovoltaics are an important source of renewable energy, but due the intermittent nature of insolation, solar cells usually need to be connected to rechargeable batteries, electrochemical capacitors or other energy storage devices, which adds to the complexity and cost of these systems. In this work, we report a cathode design for photo-rechargeable zinc-ion batteries (photo-ZIBs) that is inherently capable of harvesting sunlight to recharge without the need for external solar cells. The proposed photocathodes comprising a composite of vanadium dioxide nanorods and reduced graphene oxide, are engineered to provide the necessary charge separation and storage for photocharging under illumination. The photo-ZIBs achieve gravimetric capacities of ~ 282 mAh g-1 in the dark and ~ 315 mAh g-1 under illumination, at 200 mA g-1, demonstrating the use of light not only to charge the deceives, but additionally to enhance their capacity. The photo-ZIBs also demonstrate enhanced high-rate capabilities under illumination, as well as a capacity retention of ∼ 90% over 1000 cycles. The proposed photo-ZIBs demonstrate a promising new technology for addressing energy poverty, due to their high performance and inherent cost-efficiency and safety.Newton International Fellowship-Royal Society (UK) grant NIF∖R1∖181656
ERC Consolidator grant MIGHTY - 866005
EPSRC Graphene CDT EP/L016087/
Microwave-promoted one-pot synthesis of 4H-thiopyrans from a,b-unsaturated ketones via a three-component reaction
—An efficient one-pot synthesis of substituted 4H-thiopyrans has been accomplished from a three-component reaction of
a,b-unsaturated ketones, Lawesson’s reagent and alkynes under microwave irradiation
Determinants of impact : towards a better understanding of encounters with the arts
The article argues that current methods for assessing the impact of the arts are largely based on a fragmented and incomplete understanding of the cognitive, psychological and socio-cultural dynamics that govern the aesthetic experience. It postulates that a better grasp of the interaction between the individual and the work of art is the necessary foundation for a genuine understanding of how the arts can affect people. Through a critique of philosophical and empirical attempts to capture the main features of the aesthetic encounter, the article draws attention to the gaps in our current understanding of the responses to art. It proposes a classification and exploration of the factors—social, cultural and psychological—that contribute to shaping the aesthetic experience, thus determining the possibility of impact. The ‘determinants of impact’ identified are distinguished into three groups: those that are inherent to the individual who interacts with the artwork; those that are inherent to the artwork; and ‘environmental factors’, which are extrinsic to both the individual and the artwork. The article concludes that any meaningful attempt to assess the impact of the arts would need to take these ‘determinants of impact’ into account, in order to capture the multidimensional and subjective nature of the aesthetic experience
Phosphate solubilizers enhance NPK fertilizer use efficiency in rice and legume cultivation
It has been reported that phosphate solubilizing bacteria (PSB) are the most promising bacteria among the plant growth promoting rhizobacteria (PGPR); which may be used as biofertilizers for plant growth and nutrient use efficiency. Moreover, these soil micro-organisms play a significant role in regulating the dynamics of organic matter decomposition and the availability of plant nutrients such as nitrogen (N), phosphorus (P), potassium (K) and other nutrients. Through this study, the management of nutrient use efficiency by the application of PSB was targeted in order to make the applied nutrients more available to the plants in the rice (Oryza sativa) and yardlong bean (Vigna unguiculata) cultivation. Results have shown that the treatments with PSB alone or in the form of consortia of compatible strains with or without the external application of chemical NPK gave more germination index (G. I.) from 2.5 to 5 in rice and 2.7 to 4.8 in bean seeds. They also showed a higher growth in both shoot and root length and a higher biomass as compared to the control. This gives us an idea about the potentiality of these PSB strains and their application in rice and yardlong bean cultivation to get a better harvest index. Their use will also possibly reduce the nutrient runoff or leaching and increase in the use efficiency of the applied fertilizers. Thus, we can conclude that the NPK uptake and management can be improved by the use of PSB in rice and yardlong bean cultivation, and their application may be much more beneficial in the agricultural field
Photo-Response of Functionalized Self-Assembled Graphene Oxide on Zinc Oxide Heterostructure to UV Illumination
- …