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AbstractNanocomposites, produced through mechanical blending, serve to enhance thermal performance of heat exchangers, solar collectors, and photovoltaic-thermal systems. This work employs an experimental methodology to assess the thermal charging (TC) and thermal discharging (TDC) of a composite generated by mixing graphene oxide (GO) and paraffin wax. TC and TDC of the GO-reinforced paraffin wax-based phase change material (PCM) have been examined across different flow rates (0.375, 0.75, and 1.5 L/min) and concentrations of GO (ranging from 0.25 to 1.00 vol%). The results exhibit a direct correlation between TC, TDC and efficiency, and reaction parameters (flow rate and volume concentration of GO). The experimental and predicted values of TCs, TDCs, and efficiencies fell ±15% (for TC and TDC), and ±9% for thermal efficiency, demonstrating a satisfactory level of agreement. This holds a practical application and valuable predictive tool for estimating TC, TDC, and thermal efficiency on known flow rates and concentrations of GO in wax-based PCMs. [ABSTRACT FROM AUTHOR]

AbstractThis paper aims to introduce the concept of nilpotency and capability in multiplicative Lie algebras. Also, we see the existence of covers of a multiplicative Lie algebra and thoroughly examine their relationships with capable and perfect multiplicative Lie algebras. [ABSTRACT FROM AUTHOR]

Retracted publications are the scholarly articles that have been withdrawn from publication by authors or journals due to errors, misconduct, or ethical concerns. The present study aims to identify and analyse retracted papers by Indian authors. The data was extracted from the Scopus and also checked from the Retraction Watch database along with the journal's website. The extracted data was analysed using MS Excel, Jamovi, and SPSS-21. The study examined the year-wise retraction rate, reasons for retraction, authorship patterns, time lag for retraction, and impact on citations after retraction. The results showed that while the number of retracted publications per year increased over time, the rate of retraction per 10K publications remained constant. Duplicate publication and plagiarism were the most common reasons for retraction. Approximately one-third of the publications were retracted within six months, and the retraction time decreased over the years, especially in open-access journals. The average number of citations per paper per year before and after retraction were nearly similar. This study could assist librarians and researchers in understanding retractions, avoiding their use, and being cautious when referencing them. [ABSTRACT FROM AUTHOR]

Tioconazole (TCZ), an antifungal medication of the imidazole class has been investigated by experimental FT-IR, FT-Raman, UV–vis and NMR spectroscopy. The optimized molecular geometry and vibrational wave numbers were calculated by DFT/B3LYP/6–311++G(d, p). The detailed vibrational assignments were made by Potential Energy Distribution. The electrophilic and nucleophilic reactive sites were studied using MEP surface. The NBO analysis has been done to describe various hyper-conjugative interactions responsible for the stabilization of the molecule. The 1H NMR chemical shifts were calculated by GIAO method and these matched well with the experimental results, indicating the accuracy of calculation method. TD-DFT calculations have been performed to determine several electronic properties like excitation energies, oscillator strengths, wavelengths and HOMO-LUMO energies. The lipophilicity and aqueous solubility of the compound have been predicted by ALOGPS method. The log P value for TCZ approaches that this compound is less recommended for oral administration. Docking studies have been made to predict the binding orientation, affinity and antifungal activity of the compound. [ABSTRACT FROM AUTHOR]

Saltpans in South India experience intense sunlight and ultraviolet radiation (UV). Therefore, it was hypothesized that halophilic bacteria living there could tolerate UV radiation. To test this, sediment and water samples from the Marakkanam Saltpan were collected and exposed to an artificial UV-B lamp. After irradiation, an aliquot of the sample was spread on nutrient agar (prepared in sterilized source water), and two bacterial strains were obtained, named SBO and SBY. Based on 16S rRNA gene phylogeny, these strains were identified as Bacillus sp. and Pontibacillus salipaludis, respectively. Another aliquot of the UV-B-exposed sample was inoculated into the nutrient broth (in sterilized source water), and incubated for a week in the dark. Later, it was subjected to Illumina MiSeq-based sequencing for the V3-V4 region (16S rRNA gene). Results revealed the presence of 13 bacterial phyla. However, the phylum Bacillota (48.59%) and Pseudomonadota (27.36%) accounted for more than 75% of the diversity. Pontibacillus was the most abundant genus, accounting for 44% of total bacterial diversity. The whole genome of P. salipaludis was sequenced on Illumina HiSeqX to decipher possible genes and pathways involved in UV-B tolerance. The genome size was estimated to be 4.05 MB, with a mean G + C content of 40.82%. RASTtk-based genome annotation revealed 4217 coding sequences and 78 RNAs. Related to the UV-B tolerance, sixteen genes involved in carotenoid and prodigiosin biosynthetic pathways were found. antiSMASH showed the presence of terpene-type carotenoids. More than sixty genes involved in various DNA repair pathways were found. [ABSTRACT FROM AUTHOR]

This article presents a study on Electromagnetic radiation (EMR) energy harvesting characteristics of lead zirconate titanate (PZT) of soft grade (SP 5 A) samples under drop weight impact load. In the present study, four samples having different diameter to thickness (d/t) ratio were used. A possible EMR energy harvesting mechanism from these samples under impact loading has been discussed. It is found that the EMR parameters viz. EMR voltage, generated EMR energy, and so on, depend on the dimension of the sample and applied mechanical energy. The sample having highest t/d2 (0.069) produces maximum EMR voltage, that is, 2.31 V. Also for the same sample, EMR parameters increase with the increase in applied mechanical energy. Also an increasing pattern of EMR energy was observed with the increase in the capacitance value of the capacitor. The results obtained suggest the possibility of using PZT as a better option for energy harvesting, sensing, and structural health monitoring applications. Also the results suggest EMR technique as an alternative option for harnessing energy from piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Predatory publishing is the unethical and dishonest behavior of publishers who take advantage of researchers by charging them too much money and not providing good editing and peer-review services. Scholars, publishers and policymakers are seeking solutions to combat predatory publishing, which has become a major academic problem. This research paper provides a bibliometric analysis of the citation patterns and trends in the predatory publishing literature. The study analyzed the 100 top-cited papers on predatory publishing and provided insight into the types of documents, journals, authors, and countries that contributed to this field. The average citation per paper in the top 100 selected publications was 53.67. Open-access publications received a significantly higher average citation per paper than subscription-based papers. "Article" was the major type of document published, followed by "Notes," "Reviews" and "Editorials." Nature and Learned Publishing were the journals that contained the highest number of top-cited articles. J. Beall and D. Moher authored the highest number of papers, while A. Grudniewicz had the highest average citation per paper. USA and Canada were the top countries in these top-cited publications. This study will be beneficial to the all the stakeholders who may be interested in this area of research. [ABSTRACT FROM AUTHOR]

Abstract This article’s primary focus is on analyzing the impact of heat generation/absorption and nonlinear thermal radiation on the mixed convective flow of hybrid nanomaterials around a rotating sphere. Due to many applications which could be encountered in spin-stabilized missiles, cooling of spinning machinery segments, medication transfer, electrolysis management, and many other industrial applications research into convective flow across a rotating sphere is progressively increasing. A combination of copper and aluminum oxide was added to the base fluid (Al2O3 − Cu/H2O) to improve its thermal conductivity. The current investigation additionally considers nanoparticles of varying shapes. Using a computational technique known as the Keller-Box method, we find a numerical solution to the fluid flow of hybrid nanofluid problem. The study uses graphical representations and in-depth explanations to show how different flow parameters affect temperature and velocity profiles. Additionally, numerical outcomes for the skin friction coefficient and Nusselt number for various parameters are shown in tabular form. Rotational speed of sphere rises because tangential velocity at the boundary of the sphere increases under the influence of rotational parameter and acceleration factor. The ratio of fluid to surface temperatures (temperature ratio) rises, results in acceleration of the heat transfer rate from the hybrid nanofluid to the boundary of the rotating sphere. The findings have a wide range of enticing applications and can be useful in designing and optimizing heat transfer systems involving nanofluid. [ABSTRACT FROM AUTHOR]

In the present study, Porcine 60K SNP genotype data from 69 Landlly pigs were used to explore Copy Number Variations (CNVs) across the autosomes. A total of 386 CNVs were identified using Hidden Markov Model (HMM) in PennCNV software, which were subsequently aggregated to 115 CNV regions (CNVRs). Among the total detected CNVRs, 58 gain, 49 were loss type while remaining 8 events were both gain and loss types. Identified CNVRs covered 12.5 Mb (0.55%) of Sus scrofa reference 11.1 genome. Comparison of our results with previous investigations on pigs revealed that approximately 75% CNVRs were novel, which may be due to differences in genetic background, environment and implementation of artificial selection in Landlly pigs. Functional annotation and pathway analysis showed the significant enrichment of 267 well-annotated Sus scrofa genes in CNVRs. These genes were involved in different biological functions like sensory perception, meat quality traits, back fat thickness and immunity. Additionally, KIT and FUT1 were two major genes detected on CNVR in our population. This investigation provided a comprehensive overview of CNV distribution in the Indian porcine genome for the first time, which may be useful for further investigating the association of important quantitative traits in Landlly pigs. 115 CNVRs were identified in 69 Landlly pig population. Approximately 75% detected CNVRs were novel for Landlly population. Significant enrichment of 267 well-annotated Sus scrofa genes observed in these CNVRs. These genes were involved in different biological functions like sensory perception, meat quality traits, back fat thickness and immunity. Comprehensive CNV map in the Indian porcine genome developed for the first time. [ABSTRACT FROM AUTHOR]

Using the latest National Sample Survey (NSS) education round data, we examine the patterns and determinants of demand and cost of private coaching in higher education in India. Two-step Heckman selection equation results find that students with better household resources (rich and educated) are more likely to take private coaching and tend to spend more on it. Results show that not only pro-male gender discrimination is in existence; there is also caste inequality in the demand and cost of private coaching, with a higher marginal effect among poor households. The study establishes that the market of shadow education, which by its very nature, is highly selective and delivers the service largely to the students of socially and economically well-off families. This article provides a rationale to consider the dynamics of inequalities in access to private coaching while devising educational policies, for making higher education egalitarian. [ABSTRACT FROM AUTHOR]

In the current communication, we assessed the current spread and invasion pattern of a new invasive alien plant Wigandia urens along National Highway 58 in the Indian state of Uttarakhand. The population status of this species was assessed using systematic vegetation sampling. Ecological niche modelling was performed using maxent to predict the future spread. The study revealed that W.urens is rapidly invading along the road on rocky eroded slopes. The actual distribution of this species is 30 km. Spatial analysis revealed that a 202 km2 area along river valleys is vulnerable in the near future. It is submitted that the low-lying areas along river catchments between 300 and 1000 m elevations might be the potential niche. Therefore, mechanical removal by uprooting the whole plant at regular intervals and monitoring of invaded sites would be the practical solution. [ABSTRACT FROM AUTHOR]

The recent COVID-19 pandemic brought the physical and virtual worlds closer and expedited the adoption of online shopping. In the context of pre- and post-COVID-19 scenarios, this paper establishes the relationship between the growth in online shopping, the shift in in-store grocery and non-grocery shopping trips, and the reciprocity among variables. A random sample of 1646 household responses from Nagpur city was used to develop multiple regression models to explore the interrelationship of these activities and their impact on conventional shopping and travel demand. Model results show the complex interplay between socio-demographic and shopping behaviour variables. The findings suggest incorporating the interplay impacts into travel demand forecasting models. It also highlights the possible effects on urban land use and transport planning. Finally, the study suggests integrating urban land use and transport planning at the activity level for a comprehensive approach. [ABSTRACT FROM AUTHOR]

Abstract The high viscosity of Indian heavy crude oils makes their pipeline transportation highly complicated and challenging. A huge pressure drop is observed while transporting heavy crude through pipelines. The present article addresses this complication by preparing a surfactant stabilized heavy crude oil-in-water (O/W) emulsion of a flowable viscosity to ease flow through pipelines. Different O/W emulsion samples were prepared with varying concentrations of a novel anionic surfactant, linear alkylbenzene sulfonic acid (LABSA), to achieve an optimized formulation based on rheological and stability studies. The article also discusses the effect of varying surfactant concentrations on interfacial tension, droplet size and distribution, and zeta potential of the developed emulsions. The optimized emulsion, having 60 vol% oil and 2 wt% surfactant, was further considered to simulate and analyze the flow characteristics (static pressure and velocity profiles) across the horizontal pipelines of three different inner diameters (0.1, 0.05, and 0.025 m) under three different inlet flow velocities (0.1, 0.05, and 0.001 m/s), using a computational fluid dynamics (CFD) approach. A remarkable decrease in the viscosity of heavy crude was noted after emulsification. Subsequently, the pressure drop across the pipeline was reduced significantly by order of three for the flow of O/W emulsion when compared to that of the heavy crude oil through a pipe diameter of 0.1 m at an inlet velocity of 0.1 m/s. The static pressure drop across the pipeline decreased with the increase in the pipe diameter; in contrast, it increased with the increase in the inlet velocity. [ABSTRACT FROM AUTHOR]

The cover gas space is an inert isolation layer provided for sodium systems in sodium-cooled fast reactors. During normal reactor operation, sodium aerosols are generated continuously in the cover gas space. Understanding the complex dynamics of the evolution and transport of the aerosol is essential from the perspective of the reactor operation. Such assessments provide vital insights into deposition patterns of aerosols to the components mounted on the roof slab. In the present manuscript, the evolution and transport of aerosol in the cover gas space as well as in roof-slab annular gaps are studied in detail with the help of computational fluid dynamics tool. The present model is validated against the experimental data from the literature. There is good agreement between temperature variation, aerosol number and mass concentration across the cover gas height. Post validation, the study of thermal and aerosol transport in the full-scale reactor cover gas for a medium-sized reference reactor is carried out. It is observed that aerosol sizes greater than ∼31 μm are mostly concentrated near either the sodium pool surface, component wall or near the vessel boundary. It is found that the average mass concentration in the cover gas space is uniform (∼ 29 g/m3). However, the annular regions are found to have a non-uniform distribution of aerosols with heavier particles confined to the lower annular regions in wavy like patterns having the same Count Mean Diameter (CMD) as in the bulk cover gas space. The CMD in the top annular regions is ∼ 2 μm. Copyright © 2023 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

This work presents the impact generated energy harvesting characteristics of cement/lead zirconate titanate (Pb(Zr0.52Ti0.48)O3; PZT) composites. A soft grade PZT (SP 5 A) with ∼1 µm sized particles in an unpoled state was utilised to prepare cement/PZT composites. The experiments were performed on 28 days' water cured unpoled samples. The total cumulative volume and average pore radius are observed to decrease with PZT concentration in the composite. The values of piezoelectric coefficient and capacitance were, respectively, found to increase by 300 and 275% for cement/PZT composites consisting of 40% PZT compared to that of 5% added PZT. The impact generated voltage and energy increases significantly with increasing PZT-content. The voltage generation from cement/PZT could be because of the oscillations of dipoles and the mobility of ions in the pores of the hydrated cement. The results obtained foreshadow the prospect of utilising cement/PZT composites for energy harvesting from civil structures, structural health monitoring, and as sensors. [ABSTRACT FROM AUTHOR]

The tremendous applications of unmanned aerial vehicles (UAVs), such as inspection in complex environments, search, and rescue missions, have established this area of research. The domain of UAVs autonomous navigation and landing has received considerable amount of interest of robotics researchers in the past decades. Nevertheless, the limited capability of UAVs for autonomous landing severely hampers the use of aerial vehicles specially in GPS-denied areas. Fortunately, with the rapid development of computer vision, vision-based techniques have become an important and cheap tool to be used in UAVs for moving target detection and landing. In this paper, four major vision-based techniques namely PID controller, fuzzy logic, sliding mode control and model predictive control have been investigated and their landing performance is compared to each other. These landing techniques are implemented on a quadcopter for the purpose of ground moving target detection and then landing on it. The Raspberry Pi board with two Pi cameras for 3D scene construction and depth estimation along with ultrasonic sensor have been used in the quadcopter. A wheeled mobile robot with landing platform is taken as the target. The landing performance of different techniques has been observed and compared in terms of landing displacement error, time taken and the distance travelled to finish the operation in an open and obstacle-free environment. The simulation results are further verified by the hardware experiments. [ABSTRACT FROM AUTHOR]

A dual-band 2 × 1 multiple-input-multiple-output (MIMO) antenna based on substrate integrated waveguide (SIW) cavity for both satellite (in K-band) and 5 G applications is proposed. Initially, the SIW cavity consisting of metallic vias on all four sides is implemented. For MIMO configuration, this cavity is divided into two smaller SIW cavities using a row of metallic vias and excited using the coaxial feed. By etching an asymmetric cross-slot (AXS) with tuned dimensions on top of the SIW cavity, a dualsense of circular polarisation (CP) in both frequency bands is obtained. The fabricated prototype of the proposed SIW antenna shows impedance bandwidth (IBW) of 15.36% (22.60–26.36 GHz; BandI) and 4.64% (29.04–30.42 GHz; BandII). The completely overlapping axial-ratio bandwidth (ARBW) with IBW of 15.16% (22.62–26.33 GHz) and 3.10% (29.20–30.12 GHz) with a peak gain of 12.47 and 7.71 dBi is obtained in BandI and Band II, respectively. The proposed antenna shows front-to-back ratio (FBR) of more than 20 dB in both resonating frequency bands. The measured results of the proposed MIMO antenna agree well with the simulation. [ABSTRACT FROM AUTHOR]

In this article, we study the numerical properties of the recently developed local (element-domain) harmonic basis function enriched finite element (FE) for wave propagation problems. The study includes the effect of the enrichment harmonics on the conditioning of system matrices and how the diagonal scaling mass lumping technique influences the possible illconditioning and the solution accuracy. Subsequently, a wave packet enriched thermoelectromechanical FE formulation is presented for axisymmetric and planar wave propagation problems in piezoelastic media. The conventional Lagrange interpolations for the displacement, temperature, and electric potential fields are enriched with the element-domain sinusoidal functions which satisfy the partition of unity condition. The extended Hamilton's principle and constitutive relations of the Lord-Shulman and Green-Lindsay generalized piezothermoelasticity are employed to derive the coupled system of equations of motion which is solved using Newmark-b direct time integration scheme. The performance of the proposed elements is assessed and wave characteristics are studied for the problems of thermoelastic shock waves in an elastic annular disk and thermoelectric shock waves in a piezoelectric hollow cylinder. The element shows significant improvement in the computational efficiency and accuracy over the conventional FE for these problems involving sharp discontinuities in the fields at the wavefronts. [ABSTRACT FROM AUTHOR]

The present study describes the isolation and structural elucidation of bioactive natural products from the hydro ethanol extract of Dilenia indica L. barks (DIHEEB) and their inhibitory activity against α-amylase and α-glucosidase enzymes. Some natural products including n-nonyl oleate (1), stigmasterol (2), β-sitotenone (3), betulin (4), and betulinic acid (5) were isolated from the DIHEEB extract. These natural products were characterized through IR, NMR, and mass spectroscopy. Among all these compounds, 4 and 5 have shown significant activity to inhibit α-glucosidase and α-amylase, which proves their anti-diabetic effect. The α-amylase and α-glucosidase inhibitory activity of 4 (α-amylase: IC50 68.79±1.6 μg/ml; α-glucosidase: IC50 69.19±1.8 μg/ml;) are very much comparable with known anti-diabetic drug acarbose (IC50 64.70±1.6 μg/ml). But compound 5 also shows a comparable extent of activity against α-amylase and α-glucosidase and it is also well established in the literature. Molecular docking and other in-silico properties were studied to elucidate the interactions and conformations of the isolated molecules with the target protein enzyme. With minimal conformational energy, 4 and 5 bind to the α-amylase (PDB ID: 4GQR) and α-glucosidase (PDB ID: 3A4A) enzymes, as proved by their respective docking score (-8.2 and -9.4 kcal/mol) and having different types of binding interactions. Also, the pharmacokinetics (PK), drug-likeness scores (DLS), and well permeability properties were studied along with no violation of Lipinski's rule. Both in vitro and in silico results suggest that D. indica could be a potential source of anti-diabetic formulations. [ABSTRACT FROM AUTHOR]

North-Eastern India is blessed with a vast diversity of rice genotypes with varying yielding abilities. However, the predominant strong soil acidity induced nutrient stresses from the toxicity of aluminum (Al3+) ions often causes sub-optimal rice productivity. The lack of suitable nutrient media for the screening of aluminum (Al) toxicity tolerance of rice genotypes is one of the limiting factors in Al tolerant varieties' development. Modified Magnavaca's solution has been the most recommended nutrient solution for this purpose where ammonium nitrate is the primary nitrogen source. However, strict regulations related to the handling and storage of ammonium nitrate in India limit the preparation of Modified Magnavaca's solution for laboratory use. Here, a modified ammonium nitrate-free formulation based upon the Magnavaca's solution has been proposed. The modified formulation was found to have 160.9 µM of active Al3+ concentration when 550 µM of aluminum chloride hexahydrate (AlCl3.6H2O) was added at pH 4.1 to the solution. Through a plant growth screening experiment using ten diverse rice genotypes a significant difference in the response of various genotypes to differential Al toxicity levels on root growth performance indicators was observed. Based on the response, we could able to categorize the genotypes into tolerant and sensitive in relative terms. Thus, the present experiment provided an important nutrient formulation suitable for screening rice genotypes under Al toxicity conditions. Moreover, the selected tolerant and sensitive genotypes can further pave the way for studying the molecular mechanism of Al toxicity response in rice and their use in the breeding program. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to enrich the theoretical system of the linear canonical Fourier transform (LCFT) by introducing the canonical potential J m , A and corresponding L p -Sobolev space. Moreover, the Schwartz-type space S A is introduced. Further, pseudo-differential operator (PDO) is defined and obtained its another integral representation. The L p -boundedness result for the pseudo-differential operator associated with the LCFT is discussed. Some applications of Sobolev-type spaces H A m , p and H A m , p are given. [ABSTRACT FROM AUTHOR]

Abstract Leaf chlorophyll is vital for plants because it helps them get energy through the process of photosynthesis. The present review thus examines various leaf chlorophyll content estimation techniques in laboratories and outdoor field conditions. The review consists of two sections: (1) destructive and (2) nondestructive methods for chlorophyll estimation. Through this review, we could find that Arnon’s spectrophotometry method is the most popular and simplest method for the estimation of leaf chlorophyll under laboratory conditions. While android-based applications and portable equipment for the quantification of chlorophyll content are useful for onsite utilities. The algorithm used in these applications and equipment is trained for specific plants rather than being generalized across all plants. In the case of hyperspectral remote sensing, more than 42 hyperspectral indices were observed for chlorophyll estimations, and among these red-edge-based indices were found to be more appropriate. This review recommends that hyperspectral indices such as the three-band hyperspectral vegetation index, Chlgreen, Triangular Greenness Index, Wavelength Difference Index, and Normalized Difference Chlorophyll are generic and can be used for chlorophyll estimations of various plants. It was also observed that Artificial Intelligence (AI) and Machine Learning (ML)-based algorithms such as Random Forest, Support Vector Machine, and Artificial Neural Network regressions are the most suited and widely applied algorithms for chlorophyll estimation using the above hyperspectral data. It was also concluded that comparative studies are required in order to understand the advantages and disadvantages of reflectance-based vegetation indices and chlorophyll fluorescence imaging methods for chlorophyll estimations to comprehend their efficiency. [ABSTRACT FROM AUTHOR]

A single-phase two-stage AC/DC/AC converter topology is investigated in this paper, which involves multi-winding transformer-fed multi-cell AC/DC and cascaded H-bridge multi-level (CHBMLI) DC/AC converter stages. Both the converter stages utilize current control using the fixed and uniform switching methods, which simultaneously achieve the regulation of the DC link voltages of all the cells. The proposed control loop for the AC/DC converter stage uses a single-voltage sensor to control the DC link voltages of all the cells using self-voltage regulating property of the multi-winding transformer. This single-control loop uses the feedback of the instantaneous AC current at the primary of the transformer and any one of the DC link voltage to achieve the input AC current control and multiple DC link voltage control. The fixed frequency ramp comparison current control in AC/DC stage of the converter provides a uniform switching cycle among all the units. A phase-shifted multi-carrier PWM (PS-MCPWM)-based fixed frequency current control of the DC/AC converter comprising CHBMLI provides equal loading across all DC links of the AC/DC converter. The results are verified through PSCAD simulations and experimental results are obtained through the LabVIEW FPGA controller implemented for two-cell, five-level converter topology. [ABSTRACT FROM AUTHOR]

Barium Titanate (BaTiO3) nanoparticles were mixed with a stock paste containing an acrylate-based binder to prepare pigment paste. The formulated paste was applied to the cotton fabric by utilizing screen printing followed by drying and curing. The coated fabric was characterized for surface and elemental composition and uniform deposition of BaTiO3 nanoparticles was observed with minimal agglomeration. The resultant fabric showed an effective bacterial reduction greater than 99% against Escherichia coli and Staphylococcus aureus, and after 15 laundering cycles, the modified fabric showed a bacterial reduction of over 98%. The loaded fabric is capable of blocking harmful ultraviolet (UV) radiations. The modification of the cotton surface did not significantly change its intrinsic properties like water vapor permeability, air permeability, fabric stiffness, and other mechanical properties. The developed product has considerable possibilities and provides a good substitute for antibiotic materials for use in medical products and everyday apparel. [ABSTRACT FROM AUTHOR]

The present study highlights the long-term variations in temperature and precipitation using time series datasets of CRU and ERA5-Land across the Himalayan region. The Mann-Kendall and Sen’s slope-based trend analysis exhibited an apparent warming trend in the region, with higher increase in Tmin (1.5°C) and comparatively lower increase in Tmax (0.8°C) during 1901–2018. The joint CCl/WCRP/JCOMM based 19 extreme indices elucidated an increasing frequency of warm days (16%) in Central Himalayan urban agglomerations (HUAs) with a declining number of cold days (-6%) and cold nights (-4%) during 2000–2019. The moderate decline in the wet days (8%) and consecutive wet days (-5 days/20 years) observed in all HUAs compared to an increasing frequency of the consecutive dry days (3 days/20 years). Study reported higher warming in Kathmandu UA, while increased precipitation in Srinagar UA, and contributes to framing climate change adaptation and mitigation strategies in the mountainous system. [ABSTRACT FROM AUTHOR]

This study evaluated the COVID-19 risk considering positive cases (as a hazard) and the demographic structure (as a socio-economic vulnerability) at districts scale across India using fuzzy analytical hierarchical process and geospatial modelling. Despite the fact that the high and very high COVID-19 hazard was observed in a limited area (14.2%, 233 districts), the proportion of high to very high COVID-19 risk was evident in larger regions (42.5%, 575 districts). A moderate to very high socio-economic vulnerability was recorded in major parts of the country (60.0%, 557 districts), while the districts with megacities had been severely affected due to the more complex urban and social systems. The study highlights the zones under high COVID-19 hazard and its possible linkages with vulnerability and risk at district scales in India that may effectively support emergency preparedness and response mechanisms during the different waves of the pandemic. [ABSTRACT FROM AUTHOR]

In search of selective carbonic anhydrase (CA) IX inhibitors endowed with apoptotic inducing properties, we designed and synthesised two subsets of 4- and 3-(5-aryl-(4-phenylsulphonyl)-1H-1,2,3-triazol-1-yl)benzene-sulphonamides. All compounds were assayed for human carbonic anhydrase (hCA) isoforms I, II, IV, and IX inhibition. Isoforms hCA I and hCA IV were weakly inhibited by most of the synthesised compounds. Many four-substituted benzenesulphonamides displayed low nanomolar inhibition against isoform hCA II, unlike the three-substituted analogues. All target compounds exhibited good inhibition profile with KI values ranging from 16.4 to 66.0 nM against tumour-associated isoform hCA IX. Some selective and potent inhibitors of hCA IX were assayed for in vitro apoptotic induction in goat testicular cells. Compounds 10d and 10h showed interesting apoptotic induction potential. The present study may provide insights into a strategy for the design of novel anticancer agents based on hCA inhibitors endowed with apoptotic interference. [ABSTRACT FROM AUTHOR]

In this article, we investigated the effects of different functional groups in graphene on the mechanical performance of epoxy nanocomposites fabricated using the in-situ polymerization method. This study considered pristine graphene and three different varieties of functionalized graphene (–NH2, –COOH, and –OH) with varying weight percent (i.e., 0.25, 0.5, and 1.0 wt%). The functional groups grafted of graphene have been confirmed through Fourier transforms infrared (FTIR) spectra. Microstructural features and fracture surfaces were also examined by field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy. In comparison to pure epoxy, –OH functionalized graphene/epoxy nanocomposites showed a maximum improvement of 37.24% in tensile strength and 38.05% in flexural strength. The improved mechanical properties of epoxy nanocomposites were attributed to homogeneous dispersion, graphene bridging, and better interfacial contact between epoxy and graphene. The effect of pristine and functionalized graphene on the mechanical properties of epoxy nanocomposites was studied. Nanocomposites were fabricated for three different wt% (0.25, 0.5, and 1.0) of graphene nanofillers. Field emission scanning electron microscopy (FE-SEM) with EDX was used to examine the microstructural features of fractured surfaces. Graphene enhanced the mechanical properties of epoxy nanocomposites. [ABSTRACT FROM AUTHOR]

The study aimed to determine the above-ground biomass (AGB) of tropical deciduous forests in Central India using field-based techniques and spaceborne quad-pol ALOS PALSAR-2 L-band and dual-pol Sentinel 1A C-band synthetic aperture radar (SAR). Field sampling based on 73 forested grids exhibited a diverse forest composition in the Satpura Tiger Reserve (STR) with a total of 54 tree species of which 31.48% species were IUCN Red-Listed. The forests were highly diverse (H′=3.22) with a low concentration of dominance (CD = 0.06) and a quite high species evenness (E = 0.81). The sensitivity and correlation between field-based AGB and SAR backscatter in STR were highest in cross-polarization due to its higher sensitivity to the vegetation structure in both L- and C-band SAR, where L-VH based AGB estimates were found more accurate (RMSE:5.17%). The study provided vital information for setting up strategies for biodiversity conservation, enhancing forest productivity, and restoring wildlife habitats. [ABSTRACT FROM AUTHOR]

A few decades ago, hydroelectric projects were considered a clean source of energy. The present study aims to assess the biomass and soil carbon (C) stock in the hydroelectric catchment in India and further, its implications to mitigate GHG emissions. The estimation depicts the low 'C' stock in the reservoir's catchment in comparison to reservoirs located globally in the same eco-region which will ultimately result in lower GHG emission in the future. Moreover, estimated total carbon density of the forest species was found as 54.92 ± 18.07 MgC.ha−1 while mean SOC was 79.64 ± 19.32 MgC.ha−1. The average total 'C' stock of Tehri hydroelectric reservoir's catchment was estimated as 134.56 MgC.ha−1. Moreover, ratios (total flooded carbon/installed capacity) comprised between 4 and304 kgC/W from the other reservoirs reported globally. These ratios are higher than the Tehri reservoir (0.28 kgC/W) as flooded area of Tehri reservoir during impoundment was 52 km2. Thus, Tehri reservoir was found to emit less GHG in time to come. The present study helps the hydropower industries, policymakers, and environmentalists in designing the catchment area treatment plan to minimize the negative impact of GHG on climate change. [ABSTRACT FROM AUTHOR]

One pot multi-component strategy has been developed for the synthesis of a small library of nineteen 4-aryl-1,4-dihydro-oxochromeno[3,2-b]oxoindeno[6,5-e]pyridine by the condensation of 4-aminocoumarin, aromatic aldehyde and indane-1,3-dione in acetic acid:ethylene glycol (5:1) in good yields along with the formation of di-(4-aminocoumarin-3-yl)arylmethane as by product in three cases. The use of microwave irradiation for the condensation of 4-aminocoumarin, aromatic aldehyde and indane-1,3-dione in acetic acid and ethylene glycol at 200 W and at 120 °C led to the selective formation of 4-aryl-1,4-dihydro-oxochromeno[3,2-b]oxoindeno[6,5-e] pyridine in excellent yields. Interestingly, the side product di-(4-aminocoumarin-3-yl)arylmethane could be converted exclusively to 4-(4'-nitrophenyl)-1,4-dihydro-di(oxochromeno[3,2-b:5,6-e])pyridine on microwave irradiation under identical condition. [ABSTRACT FROM AUTHOR]

The present article is focused to improve the thermal performance of solar air heater using Liquid crystal thermography (LCT) approach, an improved type solar air heater comprises of winglet type rib roughened surface. In the present case, an experimental analysis and its effects on heat transfer and collector efficiency are examined using non-dimensional roughness parameters taken as relative roughness pitch (P/e) ranges between 5–12, attack angle (α) values of 30 degree-75 degree and relative roughness width (W/w) ranges between 3–7.These experimental results when compared with the smooth channel was improved by 17 % to 46 % under the given conditions. [ABSTRACT FROM AUTHOR]

Most frequently, the South and Central Asia region witnesses small to moderate magnitude earthquakes. In the past, this situation has resulted in massive property damage and losses apart from unaccounted operational dysfunction and human injuries and losses. There is a dire need to understand the underlying factors for these losses and prepare for the continuity of facility operations with loss reduction. To understand these requirements, Aga Khan Development Network (AKDN) carried out a Disaster Risk Management Initiative programme (now part of Aga Khan Agency for Habitat) across South and Central Asia between 2011 and 2016. One of the key outcomes of the initiative was to develop a non-structural hazard mitigation methodology, which should facilitate the assessment of all AKDN facilities for their safety and continuity of operations. The present manuscript intends to discuss the systematic approach in conducting Rapid Visual Screening Surveys following the AKDN methodology to generate a priority list of structures considered for mitigation planning. In doing so, the manuscript puts focus on the detailed non-structural vulnerability assessment, which results in incremental non-structural hazard mitigation including housekeeping, bracing and anchoring Mechanical, Electrical and Plumbing (MEP) and Fixtures, Furniture and Equipment (FFEs), as well as architectural retrofitting. Various challenges are encountered during the mitigation plan implementation. So far, the developed methodology is tested on more than 5,500 individual structures. The criteria for effective mitigation implementation include safety, aesthetics, time, economy, and functionality. Another dimension of this manuscript is to discuss about implementation monitoring and how it has reduced the risk. [ABSTRACT FROM AUTHOR]

An enriched finite element formulation based on generalized piezothermoelasticity is presented for accurate solution of thermoelectromechanical shock wave propagation problems in piezoelectric continua. The conventional Lagrangian interpolations are enriched with sinusoidal wave packets in the element domain. The coupled multifield finite element equations, derived using the extended Hamilton's principle, are solved using direct time integration. The results show that the sharp jumps occurring at the wavefronts in the distributions of field variables are predicted accurately by the proposed finite element with a static uniform mesh, overcoming the problem of large spurious undulations in conventional finite element solutions at these wavefronts. [ABSTRACT FROM AUTHOR]

A numerical study is conducted to investigate the effects of thermal radiation on flame spread phenomenon close to limiting oxygen conditions in a low convective spacecraft environment. To understand the role of radiative heat loss from the flame, a set of simulations is performed where gas radiation is completely suppressed. The results show that radiation exerts a dual influence on flame spread rate depending on oxygen concentration. If there is more radiative heat loss from the flame, the limiting oxygen concentration increases, and the size of the flamelet decreases. It was observed that in the absence of gas radiation, oscillating near-limit flamelets stabilise and merge into a single flame. Further, the effects of surface radiation were studied by varying emissivity of the solid fuel and it was noted that a more emissive fuel is more susceptible to the formation of flamelets. [ABSTRACT FROM AUTHOR]

The present study was framed with the aim to develop a simple, efficient, and robust reverse-phase HPLC method for the quantification of plumbagin utilizing an analytical quality-by-design (AQbD) approach. HPLC was performed in Waters made high-performance liquid chromatography equipped with Waters 2996 photodiode array detector (detection at 254 nm), and reversed-phase Waters inertsil C18 column. The AQbD approach helps in finding the most suitable critical analytical attributes (CAAs) as well as high-risk critical method parameters (CMPs). Using the Box-Behnken Design experiment, the selected CMPs were optimized for the higher recovery of plumbagin. Further, the developed method was validated following International Conference on Harmonization (ICH) Q2 (R1) guidelines. The low divergence in intra- and inter-day experiments, and low LOD (2.4 µg/mL) and LOQ (7.2 µg/mL) values justify the high precision and sensitivity of the developed method. The developed method was further tested for the quantification of plumbagin from the two different plant source collected from two different climatic conditions. Results show that the maximum plumbagin content was found in P. indica roots. In conclusion, the AQbD approach could be used in other plant systems for the optimization of different variables to obtain a higher amount of targeted plant metabolite. [ABSTRACT FROM AUTHOR]

The Fast Fourier Transform (FFT) is one of the most important algorithm used in digital signal processing (DSP) and digital communication applications to compute fast operations. FFT and IFFT is widely used in modulation and demodulation schemes such as Orthogonal Frequency Division Multiplexing (OFDM), TV broadcasting (DVD), Digital radio broadcasting (DVB) etc. The different FFT processor architectures are used for several applications. The Xilinx ISE tool has FFT Core, which can be directly used for several applications. FFT support four types of architectures: Radix-2 lite burst I/O, Radix-2 burst I/O, Radix-4 burst I/O and Pipelined I/O. The research article focuses on the hardware chip performance analysis of the variable length FFT processor architectures on Field Programmable Gate Array (FPGA) platform using VHDL programming in which FFT length varies from 8 point to 65,536 point. The input data stream is considered of 8-bit, 16-bit and 32-bit. The estimated hardware chip performance parameters are DSP Slices and block RAM. The timing parameter are transform cycles and frequency. It is estimated that radix-2 lite burst I/O performs better in terms of hardware resource utilisation on FPGA and pipelined hardware architecture performs better in terms of transform cycles in comparison to other FFT architectures. The decoded 1024-point FFT signal is observed in Xilinx ISE software integrated Chipscope Pro-Analyzer. The analysis predicts about the best-suited FFT hardware architecture when the designer is going to design the hardware chip on FPGA platform for several applications. [ABSTRACT FROM AUTHOR]

Coal is one of the most crucial natural resources used for steel and energy production. To improve its utilization properties, the run-of-mine coal is processed to remove undesirable impurities such as mineral matter and sulfur. The fine coal is usually processed by flotation, and the efficiency is highly dependent on the particle size, maceral composition, and the rank. The effect of particle size and reagent dosages are usually the most commonly studied parameters for flotation, whereas optimization through the study of the response of the petrographic components and the rank based on the vitrinites' reflectance of coal particles (V-types) are rarely investigated. This paper studied the floatability of coal particles in terms of their physical and compositional attributes including particle size, petrographic composition, and rank (V-types) from coal blends representing different feeds to the plant. The results showed that the higher content of inertinite macerals and a high quantity of ultra-fines contributed to a poor floatability for the studied coals. On the other hand, the coal sample containing vitrinite particles from a higher rank exhibited a much better flotation response, despite the presence of significant amounts of ultra-fine. [ABSTRACT FROM AUTHOR]

A highly efficient fluorination reaction of 4,6-disubstituted aminopyrimidines using N-Fluorobenzenesulfonimide (NFSI) has been developed, presumably proceeding via C–H bond activation. Cadmium acetate was employed as the salts, and various fluorinated 4,6-disubstituted aminopyrimidines have been generated in good to excellent yields. This chemistry endows an economical method of valuable fluorinated 4,6-disubstituted aminopyrimidines through a direct C–F bond formation. [ABSTRACT FROM AUTHOR]

In the nuclear reprocessing plant, after the dissolution of spent fuel, high-speed tubular bowl sedimentation centrifuge is being used to remove the solid particles from the solvent. The performance of the system and extent of clarification of the solvent is ascertained in the chemical laboratory by drawing the sample. A noninvasive methodology, the laser obscuration, is studied for its adaptability as an online measurement tool for determination of clarification status. This would help to manipulate the operation of the centrifuge to achieve desired separation efficiency with minimum time and without interruption. In this context, the performance evaluation of a uniquely designed high-speed tubular centrifuge for reprocessing of fast reactor fuel has been carried out by using laser obscuration method. The light scattering technique has been widely used for the determination of concentration of clarification liquid. In addition, the size distribution is also ascertained in our study, which is useful to determine the grade efficiency of centrifuge system. Two different particulate liquid suspensions namely ferric oxide (Fe2O3) and zirconium molybdate suspended in de-ionized water are used. The tubular bowl centrifuge is tested at the high-speed rotation of the inner bowl (14000–20000 rpm), various throughput of clarifier liquid (30–470 lph) and in half-loaded bowl condition. The laser obscuration method is found to be useful for ascertaining the performance of the centrifuge system and it is recommended as an online tool for monitoring and maintaining separation efficiency by adjusting rotational speed, throughput and to monitor the bowl-loading condition. [ABSTRACT FROM AUTHOR]

(100 − x)PVDF–(x) PZT (PVDF: Polyvinylidene Difluoride and PZT: Lead Zirconate Titanate) composite was prepared in 0–3 connectivity by the solvent casting methods. The piezoelectric co-efficient is found to be increased with the increase in PZT concentration in the PVDF matrix. It is due to the increase of β phase of PVDF as well as lattice strain in PZT. The incorporation of PZT ceramics in the PVDF matrix causes an increase in storage loss modulus of the sample. The tanδ decreases due to incorporation of PZT ceramics in the PVDF matrix. The piezoelectric and mechanical properties are found to be increased in the PVDF-PZT composite compare to that of PVDF. [ABSTRACT FROM AUTHOR]

Background: Studies have suggested promising evidence that glial fibrillary acidic protein (GFAP) could be used as a blood biomarker to distinguish between ischaemic stroke (IS) and intracerebral haemorrhage (ICH) in acute stage. Objective: To determine the available evidence for GFAP as a blood biomarker for differentiating ICH from IS and stroke mimics using a meta-analysis approach. Methods: Search terms were used for literature search: ("STROKE" [Mesh] OR "BIOMARKER" [Title/Abstract] OR "GFAP" [Title/Abstract])] OR "SPECIFICITY" OR "SENSTIVITY" at various search engines like PubMed, Google scholar, Trip database, clinicaltrial.gov for articles from 1990 to April 2019 using filter 'human subjects'. Data were analysed using software STATA version 13. Results: A pooled analysis including 12 studies suggested that GFAP if used as a biomarker to differentiate between different types of strokes (ICH from IS and mimics) had a sensitivity of 78% (95% CI: 67–86%) and a specificity of 95% (95% CI: 88–98%). Positive likelihood ratio (LR) was 14.4 and negative LR was 0.23. SROC with prediction and confidence contours suggests promising area under the curve 0.93, 95% CI ranges from 0.90 to 0.95. Diagnostic odds ratio with 95% CI was observed 63 (31–125). Conclusion: Our meta-analysis suggests that GFAP has a promising diagnostic accuracy for the differentiation of ICH from IS and mimics. Further, phase II and phase III diagnostic test studies are required to validate the findings before using GFAP as a blood based biomarker for clinical use. Trial Registration: This study was registered in OSF registries 10.17605/OSF.IO/B9JP4 [ABSTRACT FROM AUTHOR]

Simulation of molecular dynamics (MD) allows mimicking the systematic variation of mechanical properties beyond the capacity of experimental methods. In this review, the status of the molecular modelling, simulation and mechanical and thermal characterisation of graphene and the properties of bulk nanocomposites using MD are extensively examined. The molecular models of graphene (pristine and functionalised), and the most common epoxy matrix with preeminent MD energy minimisation tools are thoroughly examined. The presence of MD's simulation setup and the computational procedure for different styles of mixing the polymer matrix with graphene as nanofiller are exhaustively reviewed. In particular, in the analysis of several papers on graphene and their composites, it has been noticed that mechanical, thermal and interfacial properties are ubiquitous to most of the engineering applications. In this review, advances in the molecular modelling and simulation of graphene and their composites has been discussed in detail keeping graphene structures, aspect ratio, weight fraction and density effect as major factors. Finally, the research gaps and future scope are discussed, which indeed helps the researchers in scaling up their researches in graphene and their composites, which may further lead to their experimental findings. [ABSTRACT FROM AUTHOR]

Coal dewatering of fine coal is one of the major challenges faced by the coal preparation plants. The plant studied in this research is currently producing a fine coal product with 28% moisture and is required to reduce it to below 17% before this fine stream is blended with rest of the clean coal streams. A lot of dewatering aids such as surfactants, flocculants, and superabsorbent polymers are available on the market to enhance the dewatering process. The research was designed to use various dewatering aids to reduce the moisture content of this fine product without decreasing the production rate. Several commercially available chemical reagents were used to enhance the dewatering of this coal product. These reagents were selected in such a way that they could be grouped into different categories depending on their action. The results showed that the surface tension reducing reagents (STR) have a higher capability of moisture reduction than the coal hydrophobicity modifying (CHM) reagents and commonly used in filtration flocculants. Super absorbing polymers used in the dewatering of fine coal were shown to outperform all the other reagents and seem to be suited for this plant dewatering scenario. A cost-benefit analysis is required to make necessary plant modifications if they are to be used there, however, this was not in the scope of this project. [ABSTRACT FROM AUTHOR]

Fast depleting fossil fuel and its associated negative impacts on environment and climate change raising concern over clean fuel and sustainability. Thus, in line scientific community are thinking to have alternative fuels like hydrogen, natural gas, syngas, and biofuels. Furthermore, hydrogen gas is superior among alternative fuels due to its renewable nature, zero emissions, and generate large content of energy during combustion. Researcher cites on various biological methods like bio photolysis of water, dark fermentation, photo-fermentation, and microbial electrolysis cell. However, biohydrogen production from wastewater as substrate is becoming popular due to less energy intensive and sustainable way to fulfil the future energy demands. With rapid increase in industrialization and urbanization will further increase wastewater generation globally. Hence, wastewaters could have huge potential for the green hydrogen production which ultimately provides clean energy, and the low-cost wastewater treatment. Literature reveals that wastewater from various industries like citric acid, cheese whey, paper mill, rice mill, beverage, cassava starch processing, palm oil, starch processing, pharmaceutical, food processing, distillery, and sugar industry have been utilized for biohydrogen production. Hence, the present review is focused on various wastewaters based green hydrogen production which have overall positive impacts on social, economic, and environment for the future generation. [ABSTRACT FROM AUTHOR]

Nanosized titania has promising application in the field of photocatalysis, optical coating and solar cell. Metal alkoxides based sol-gel methodology is one of the established & extensively used route for the preparation of nano-titania. In present work, nanosized titania have been prepared through sol-gel transformation of synthesised and chemically modified metal complex using titanium(IV) isopropoxide (TTIP). Modifications of metal alkoxides with chelating ligands result in the controlled condensation of TTIP. Metal complexes of TTIP were chemically modified by various schiffs bases. Phase of nano-sized titania was confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. Shape, size and surface morphology were examined using scanning electron microscopy and high-resolution transmission electron micsroscopy. Elemental composition was investigated by energy disperse X-ray analysis. The absorption spectra and thus optical band gap were determined using Ultraviolet and visible spectroscopy. [ABSTRACT FROM AUTHOR]

Electromagnetic responses of cement-PZT composites under impact loading have been presented in this work. The values of density, dielectric constant and EMR voltage increase while that of porosity and loss tangent decrease with increase in PZT content. Filler (PZT) concentration dependent dielectric constant as well as loss tangent data shows exponential variation. The emitted EMR voltage as well as average EMR energy release rate for 21 cm height of impact increase from 1.03 V to 2.24 V and 0.10092 V2-sec/sec to 0.4635 V2-sec/sec respectively with the increasing PZT content (5% to 40%). The EMR responses of the composites were also found to be proportional to the height of impact in all the composites tested, indicating that the measurement of EMR responses from the cement based composites may be useful for deformation monitoring. [ABSTRACT FROM AUTHOR]

A unified enriched finite element (FE) formulation for two generalized thermoelsaticity theories is developed for the transient thermal shock problems in one and two dimensional domains. Both the displacement and temperature field interpolations are enriched with harmonic functions defined in the local element coordinates. The coupled field finite element equations are derived using the generalized Hamilton’s principle and solved directly in time domain using the standard Newmark-β time integration technique as opposed to the transform techniques usually adopted for thermal shock problems. The method is assessed in comparison with the Laplace transform based analytical solutions and FE solutions with dynamic meshing available in the literature. It is shown that the present solution with a static uniform mesh captures the sharp discontinuities in the temperature and displacement fields and the wave properties of heat conduction very accurately, practically eliminating the severe drawbacks of the conventional FE solutions such as the spurious undulations and flattening out, while maintaining better computational efficiency. [ABSTRACT FROM AUTHOR]

The novel unsymmetrical 3,5-dialkoxycarbonyl-2,6-dimethyl-4-(7′,8′-dimethoxycoumarin-4′-yl)-1,4-dihydropyridines and 5-acetyl-3-alkoxycarbonyl-2,6-dimethyl-4-(7′,8′-dimethoxycoumarin-4′-yl)-1,4-dihydropyridines (coumarinyl-1,4-dihydropyridines) have been synthesized by Knoevenagel condensation of 4-formyl-7,8-dimethoxycoumarin with alkyl acetoacetates in the presence of AlCl3 followed by cyclization of the resulted Knoevenagel product with other alkyl acetoacetate or acetyl acetone and ammonium acetate. The structure of the intermediate Knoevenagel product and the cyclized unsymmetrical coumarinyl-1,4-dihydropyridines has been established on the basis of their spectral data analysis and single-crystal X-ray diffraction analysis. The observed conformation of the coumarinyl-1,4-dihydropyridines holds the key to promising calcium antagonistic activity of the synthesized coumarinyl-1,4-dihydropyridines. [ABSTRACT FROM AUTHOR]

Sulfated zirconia is a very strong solid acid catalyst which can be utilized for various reactions. The present study focuses on synthesis of zirconia-based catalyst with high acidity and high surface area, particularly for isomerization reaction. Sulfated zirconia has been obtained by sulfation of zirconia prepared by hydrothermal route. The catalyst was developed by impregnating tungstophosphoric acid on sulfated zirconia by wet incipient method. The catalyst was characterized through Brunauer–Emmett–Teller (BET) surface area, temperature-programmed desorption of ammonia, temperature program reduction of hydrogen, Fourier transmission infrared spectroscopy, and thermogravimetric analysis. The results revealed that the catalyst is crystalline in nature with surface area 190–225 m2 g−1 and acidity 0.135–0.558 mmol g−1. Twenty-five percent conversion was obtained (as confirmed by gas chromatography) at 225°C using n-hexane as model hydrocarbon in fixed-bed microreactor. [ABSTRACT FROM AUTHOR]