In the present study, sensitivity of Indian Summer Monsoon (ISM) to the cumulus convection scheme (CCS) is assessed using Regional Climate Model (RegCM4.4.5). Seasonal scale ...(May–June–July–August–September) simulation of the model forced with European Centre for Medium Range Weather Forecasts reanalysis data (ERA interim) is carried out for the consecutive three monsoon years 2007, 2008 and 2009. Four major CCS (MIT, Grell, Tiedtke and Kain–Fritsch) are employed. Model simulated results are validated with various observed and reanalysis datasets. In addition, the model results are also compared with that of its earlier version (RegCM4.1). Detailed analysis reveals that the model’s ability to delineate large scale ISM features such as Heat Low, Tibetan high, Somali Jet, Tropical Easterly Jet (TEJ), Sub-tropical Westerly Jet (STWJ) are fairly well using multiple CCS options. Fairly, better model performance is identified while Grell over ocean and MIT over land (GO_ML) is used. This scheme exhibits relatively lower warm (cold) bias over entire northwest and partially central India (peninsular and other parts of India). Both lower and upper level circulation pattern including TEJ and STWJ are better simulated by GO_ML scheme. Simulated distribution of precipitation is also more realistic and closed to TRMM data using that scheme. Further comparison of results from two model versions indicates that the simulation with recent version (4.4) is more realistic than that with the earlier version (RegCM4.1). The study concludes that RegCM4.4 with GO_ML would be the optimal combination when overall performance of the model is taken into consideration.
A comparative analysis of the trigate fin-shaped field-effect transistor (FinFET) and quantum FinFET (QFinFET) is carried out by using density gradient quantization models in the Synopsys ...three-dimensional (3-D) technology computer-aided design (TCAD) platform. The gate dielectric stack comprising 0.5 nm SiO
2
(
k
= 3.9) and 2 nm HfO
2
(
k
= 22) contributes to an effective oxide thickness of 0.86 nm and is kept constant throughout the study. The results demonstrate that the QFinFET can overcome the limitations of current FinFET devices when scaling down to the atomic level. An analytical model including quantum-mechanical effects for evaluation of the drain current of the FinFET is established and validated using the TCAD software. The degradation in the drive current with downscaling of the fin thickness for the trigate FinFET and the increase in the drive current for the QFinFET are presented. The results are improved by taking into account different channel lengths and body thicknesses to estimate the drain current–gate voltage and gate capacitance–gate voltage characteristics for both the trigate FinFET and QFinFET. The drain-induced barrier lowering and subthreshold swing are also analyzed for the trigate FinFET and QFinFET at different technology nodes, revealing excellent characteristics. It is clearly established that the QFinFET can overcome the limitations faced by current FinFET devices when scaling the silicon down to the atomic level and may represent the next generation of FinFET devices.
The catalytic aquathermolysis becomes an important area for investigation to solve some of the problems during exploration of heavy crude oil. It has been reported in 1982 by Hyne et al. that metals ...can accelerate the aquathermolysis and thereafter the uses of several catalysts on this reaction have been studied. It is believed that superheated water passes heat to the hydrocarbon, and some asphaltene molecules are broken down by thermal heat to small molecules. Hence the viscosity as well as flow properties of heavy oil are improved. Moreover, the added heat provides driving force or pressure so that the viscous oils can flow easily and increases the oil production. When the catalyst is present on this reaction system, the viscosity is reduced very deeply. In general the catalysts employed for aquathermolysis are mineral, water-soluble, oil soluble, and dispersed catalyst. The viscosity reduction with these catalysts is in the order of mineral < water-soluble catalyst < oil-soluble catalyst < dispersed catalyst. It has also been found that during aquathermolysis, the saturates and aromatics increase while the amount of asphaltene and resin decreases. The use of different hydrogen donors on aquathermolysis also improves the quality of the heavy crude oil. The most commonly used hydrogen donor is tetralin. Moreover, when tetralin is used with a catalyst, the viscosity is also reduced more effectively. The use of catalysts in the real oil field indicates that the catalysts can substantially reduce viscosity and hence the catalytic aquathermolysis process can be used successfully for exploration of heavy crude oils. However, the oil soluble and dispersed catalysts are slightly more active than the water-soluble catalyst. The cost of the former two types of catalysts may be higher than the preparation cost of simple water-soluble catalysts. Therefore, more research is needed so that the catalysts can be used for this process more economically. Another problem is the efficiency of these catalysts in the oil field. The activity of the catalysts depends on the homogeneity of the temperature in the oil floor. When the superheated water is injected into the oil reservoir, the oil surface temperature is high. However, temperature is gradually lower on the depth of the oil floor, and hence the catalyst loses its activity. So, further investigation is also necessary to address this aspect.
The role of Dicer's helicase domain is enigmatic, but in vivo it is required for processing certain endogenous siRNA, but not miRNA. By using Caenorhabditis elegans extracts or purified Drosophila ...Dicer-2 we compared activities of wild-type enzymes and those containing mutations in the helicase domain. We found the helicase domain was essential for cleaving dsRNA with blunt or 5′-overhanging termini, but not those with 3′ overhangs, as found on miRNA precursors. Further, blunt termini, but not 3′ overhangs, led to increased siRNAs from internal regions of dsRNA; this activity required ATP and a functional helicase domain. Our data suggest that blunt or 5′-overhanging termini engage Dicer's helicase domain to facilitate accumulation of siRNAs from internal regions of a dsRNA, an activity suited for processing long siRNA precursors of low abundance, but not necessary for the single cleavage required for miRNA processing.
► Dicer's helicase domain is required for recognition of certain dsRNA termini ► Certain termini increase accumulation of siRNAs from internal regions of dsRNA ► The helicase domain has a similar role in C. elegans and D. melanogaster Dicer
Photon-mediated coupling between distant matter qubits may enable secure communication over long distances, the implementation of distributed quantum computing schemes, and the exploration of new ...regimes of many-body quantum dynamics. Solid-state quantum emitters coupled to nanophotonic devices represent a promising approach towards these goals, as they combine strong light-matter interaction and high photon collection efficiencies. However, nanostructured environments introduce mismatch and diffusion in optical transition frequencies of emitters, making reliable photon-mediated entanglement generation infeasible. Here we address this long-standing challenge by employing silicon-vacancy color centers embedded in electromechanically deflectable nanophotonic waveguides. This electromechanical strain control enables control and stabilization of optical resonance between two silicon-vacancy centers on the hour timescale. Using this platform, we observe the signature of an entangled, superradiant state arising from quantum interference between two spatially separated emitters in a waveguide. This demonstration and the developed platform constitute a crucial step towards a scalable quantum network with solid-state quantum emitters.
The consumption of cement in India and other emerging economies is expected to increase because of the continuing push towards development of housing and infrastructure. The increasing production of ...cement and utilization of concrete are bound to have a major impact on sustainability. The present work proposes a framework for sustainability assessment, in terms of the CO
2
emissions and energy demand, that can be adopted in cases where suitable databases are not readily available. Case studies for cement manufacture have been considered in South India, with different system boundaries such as ground-to-gate, gate-to-gate and CSI. The assessment made using data from the plant and other sources highlights the benefits of using supplementary cementitious materials (SCMs) in terms of reducing the impact of cement and concrete. More importantly, limestone calcined clay cement shows considerable promise in terms of reduction in CO
2
emissions and energy demand in both cement and concrete, with more improvement in higher grade concrete.
In this study, AA7075 matrix hybrid composite containing graphite and SiC particles was fabricated by powder metallurgy techniques. The effect of microwave sintering on the microstructure and ...mechanical properties of AA7075 + 8%graphite+2%SiC hybrid composite was investigated using SEM integrated with EDS, XRD, tensile-compression, hardness, and porosity tests. The results showed that microwave sintered composite mechanical properties were enhanced compared with conventionally sintered composite. Precise microstructure with no agglomerations and clean interfaces without any secondary phases were observed through SEM-EDS and XRD analysis for microwave sintered composite. Along with enhanced mechanical properties, a strain to fracture value of 7.98% was observed in microwave sintered composite. It was, thus, concluded that microwave sintering is preferable to conventional sintering to fabricate hybrid composites with enhanced performances.
Graphical abstract
► Alumina and alumina-titania supported CoMo catalysts show high and stable HDM and HDS activities. ► Though the initial activity of an acidic catalyst is high but the catalyst is deactivated ...rapidly. ► The nature of coke deposit of acidic and non acidic supported catalysts is slightly different. ► Coke is responsible for deactivation of alumina catalyst while coke and metals cause deactivation of mixed-oxide catalysts.
Four different CoMo catalysts supported by alumina, alumina–titania, alumina–silica and carbon were used to study the early stage of deactivation. Hydrodemetallization (HDM) and hydrodesulfurization (HDS) activities of these catalysts have been tested in high pressure, high temperature micro-plant by using heavy crude oil as feed. Thiophene activity of the spent catalysts was compared with the fresh and regenerated catalysts. The results show that the alumina and alumina–titania supported CoMo catalysts exhibit high and stable performance for both HDM and HDS activities. Though the initial activities of alumina–silica supported CoMo catalyst are high, the activities decrease rapidly with time-on-stream. Having higher acidic sites may cause this rapid deactivation. Thermogravimetric analysis results also support that the nature of deposited carbon on this catalyst is different from the coke deposited on the other three catalysts. SEM-EDX results show that vanadium sulfides are more preferably deposited at the outer surface of carbon catalyst. Thiophene HDS activity of fresh, spent and regenerated results suggest that the deactivation of alumina catalyst is cause of coke deposition whereas both metal sulfides and coke depositions are responsible for CoMo/Al2O3–TiO2 and CoMo/Al2O3–SiO2 catalysts deactivation, particularly at the early stage of hydroprocessing of the heavy oil.
Semilattice of topological groups Maity, S. K.; Paul, Monika
Communications in algebra,
20/9/2/, Letnik:
49, Številka:
9
Journal Article
Recenzirano
In this article, we establish necessary and sufficient condition on a topological Clifford semigroup to be a semilattice of topological groups. As a consequence, we show that a topological Clifford ...semigroup
satisfies the property that for each
and every
there exists an element
such that
if and only if it is a strong semilattice of topological groups if and only if it is a semilattice of topological groups. We prove that some topological properties like
regularity and completely regularity are equivalent in a semilattice of topological groups. We also prove that the quotient space of a semilattice of topological groups by a full normal Clifford subsemigroup is again a semilattice of topological groups. Finally, we establish that if
is a family of semilattices of topological groups and N
i
is a full normal Clifford subsemigroup of S
i
for all
then
is topologically isomorphic to
First of all, we indicate a severe error in the analysis of the main results of both Chakraborty
Ukr. Math. J.
,
72
, No. 11, 1794–1806 (2021) and Chakraborty–Chakraborty
Ukr. Math. J.
,
72
, No. ...7, 1164–1174 (2020) to show that both these papers cease to be true. Further, pertinent to the results of these two papers, we consider the unique range set of a meromorphic function over a non-Archimedean field with the smallest possible weights 0 and 1 under the aegis of its most general form to improve the existing result.
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