In this study, a normal form based excitation controller for oscillatory dynamics in power systems is investigated. Afterwards, instead of using a conventional linear control technique for the ...secondary controller, a novel non-linear objective for the rotor mode is considered to emulate ideal power system stabiliser (PSS) characteristics. With the aid of eigenvalue analysis, it is shown that the proposed method exhibit ideal PSS characteristics. Moreover, it is demonstrated the proposed technique is robust when compared with the conventional controllers. Time-domain simulation is performed on the third-, fourth-, and sixth-order model (i.e. IEEE model 1.0, 1.1, and 2.2) of the synchronous machines. Simulation results are shown on a single machine infinite bus power system model.
Magnetic acid activated carbons (MAAC) were prepared from the shells of Sterculia villosa Roxb by activating the biomass and magnetizing it using the co-precipitation technique. Characterization of ...MAAC prior and post adsorption was performed using various microscopic and spectroscopic analytical techniques, and they verified the formation of magnetic aggregates over porous activated carbon surface. Vibrating Sample Magnetometer (VSM) analysis confirmed the superparamagnetic behaviour of the adsorbent with saturation magnetization (Ms) value of 18.2 emu/g, causing an easy and rapid recovery from the adsorption setup in the presence of an external magnetic field. Langmuir isotherm and pseudo-second-order kinetic model best fit the experimental data with theoretical Langmuir maximum adsorption capacity as 81.97 mg/g and verifying chemisorption type of adsorption process, respectively. Thermodynamic analysis verified the interaction among adsorbate and adsorbent as endothermic, spontaneous, and thermodynamically favourable. Co-existing metal cations showed a significant reduction in ciprofloxacin removal efficiency; co-existing anions, though, showed a negligible influence on the adsorption efficiency of MAAC. Recyclability studies verified that the adsorption efficiency fell from 98% in the first cycle to 43% in the fifth cycle. The Ms value fell to 7.6 emu/g (after five adsorption cycles), affecting the adsorbent's recovery. The Phyto-toxicological assessment was performed to evaluate the environmental risk to human and aquatic life using Vigna mungo seeds. MAAC proved to be an effective and magnetically separable adsorbent for removing antibiotics.
•Magnetic acid-activated carbons (MAAC) synthesize with the co-precipitation technique.•Vibrating Sample Magnetometer analysis confirmed the magnetic properties of MAAC.•The magnetic property of MAAC maintains after five repetitive adsorption/desorption cycles.•Spent MAAC was effectively separated from the reaction mixture using a magnet.•Langmuir isotherm and pseudo-second-order kinetic model best fit with maximum adsorption capacity, 81.97 mg/g.
The role of transition metal derived cocatalyst to improve the hydrogen evolution activity of graphitic carbon nitride has been discussed.
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•Improving photocatalytic hydrogen evolution ...of graphitic carbon nitride by cocatalysts loading.•Exploring transition metal derived cocatalysts for improved charge separation and transport.•The potential use of transition metal derived cocatalyst to replace noble metal Pt.•Modulating structural features of cocatalyst for improved hydrogen evolution.•Realizing the mechanism of charge separation, transfer and recombination.
The photocatalytic production of H2 using sunlight is considered a sustainable solution to fulfill the global energy demand and reduce the emission of greenhouse gases generated from the burning of fossil fuels. H2 has the highest energy density (120–140 MJ kg−1) and produces only water as a combustion product when it reacts with O2. Therefore, it is regarded as one of the best possible contenders to meet the future energy demand. In this respect, developing efficient semiconductor-based photocatalysts is crucial to make the photocatalytic H2 evolution commercially viable. Although a series of metal-based semiconductors have been explored for the photocatalytic H2 evolution, photo-corrosion of these materials makes them impractical for long-term application. In contrast, utilization of the metal-free polymeric graphitic carbon nitride (g-CN) was beneficial to attain excellent photocatalytic activity and long term-stability (even for months). However, the poor electronic conductivity of g-CN results in charge recombination and poor charge transport to make the overall photocatalytic process inefficient. Nevertheless, effective utilization of cocatalyst like Pt can significantly improve the charge separation and transport. The high cost and scarcity of Pt lead to finding out transition metal-based cocatalysts, and the challenge is to reach an excellent photocatalytic activity and stability with transition metal-based cocatalysts when combined with g-CN. Hence, a tremendous effort has been provided to integrate transition metal-based cocatalysts with g-CN to achieve excellent photocatalytic activity, high quantum efficiency (QE), and long-term stability. Although non-noble metal-based cocatalysts attain major attention for the photocatalytic H2 evolution with g-CN, its role in improving the charge separation, recombination, and hence the H+ reduction activity was never reviewed. This review focuses on designing transition metal-based cocatalysts and their application with g-CN to improve the H2 evolution activity by enhancing the charge separation, transport, and minimizing the recombination of charge carriers. The basic principles of the cocatalyst design, their combination with g-CN, and the mechanism of electron-hole separation, charge transport, and recombination have been described. Besides, the challenges in this field have been addressed with a possible solution. Overall, this review deals with the fundamentals of photocatalytic hydrogen evolution with g-CN, recent progress in this field, and efficient utilization of the transition metal-based cocatalysts to boost photocatalytic activity.
In the present work, biocompatible materials such as niobium (Nb), zinc (Zn) and calcium (Ca) have been blended with magnesium (Mg) to develop a novel biomaterial (BM) with improved mechanical and ...corrosion resistant properties. Powder metallurgy (PM) technique was used to fabricate Mg based BM. The powder of all aforementioned materials were mixed homogenously in specific quantities to create a uniform composite component. In order to analyse the influence of process parameters on the mechanical properties of the fabricated part, experiments were performed considering central composite design (CCD). The effect of powder metallurgical parameters namely percentage Nb, compaction pressure, heating rate, sintering temperature and soaking time on the ultimate compressive strength (UCS) and sintered density was studied in the present study. It was found that the UCS and sintered density increased with increase in compaction pressure, heating rate and sintering temperature. The results also revealed that the increase in soaking time and percentage Nb, increased sintered density and UCS to a certain limit. Subsequent increase in these two parameters, sintered density and UCS decreased. Scanning electron microscopy (SEM) images of the fabricated samples showed reduction in porosity with the increase in heating rate. Moreover, X-ray diffraction (XRD) results revealed that no other phase or impurities were found during sintering of Mg based BMs. The optimum process parameters were obtained to develop Mg based BM for maximum UCS and sintered density. Furthermore, the Mg based BM samples fabricated at optimum process parameters were used for corrosion testing in simulated body fluid (SBF) solution at a temperature of 37±0.5°C. The Mg based BM yielded improved mechanical properties with reduced corrosion rates as compared to pure Mg.
In recent years, changing lifestyles and food consumption patterns have driven demands for high-quality, ready-to-eat food products that are fresh, clean, minimally processed, and have extended shelf ...lives. This demand sparked research into the creation of novel tools and ingredients for modern packaging systems. The use of phenolic-compound-based active-packaging and edible films/coatings with antimicrobial and antioxidant activities is an innovative approach that has gained widespread attention worldwide. As phenolic compounds are natural bioactive molecules that are present in a wide range of foods, such as fruits, vegetables, herbs, oils, spices, tea, chocolate, and wine, as well as agricultural waste and industrial byproducts, their utilization in the development of packaging materials can lead to improvements in the oxidative status and antimicrobial properties of food products. This paper reviews recent trends in the use of phenolic compounds as potential ingredients in food packaging, particularly for the development of phenolic compounds-based active packaging and edible films. Moreover, the applications and modes-of-action of phenolic compounds as well as their advantages, limitations, and challenges are discussed to highlight their novelty and efficacy in enhancing the quality and shelf life of food products.
Endophytic actinomycetes have shown unique plant growth promoting as well as antagonistic activity against fungal phytopathogens. In the present study forty-two endophytic actinomycetes recovered ...from medicinal plants were evaluated for their antagonistic potential and plant growth-promoting abilities. Twenty-two isolates which showed the inhibitory activity against at least one pathogen were subsequently tested for their plant-growth promoting activities and were compared genotypically using DNA based fingerprinting, including enterobacterial repetitive intergenic consensus (ERIC) and BOX repetitive elements. Genetic relatedness based on both ERIC and BOX-PCR generates specific patterns corresponding to particular genotypes. Exponentially grown antagonistic isolates were used to evaluate phosphate solubilization, siderophores, HCN, ammonia, chitinase, indole-3-acetic acid production, as well as antifungal activities. Out of 22 isolates, the amount of indole-3-acetic acid (IAA) ranging between 10-32 μg/ml was produced by 20 isolates and all isolates were positive for ammonia production ranging between 5.2 to 54 mg/ml. Among 22 isolates tested, the amount of hydroxamate-type siderophores were produced by 16 isolates ranging between 5.2 to 36.4 μg/ml, while catechols-type siderophores produced by 5 isolates ranging from 3.2 to 5.4 μg/ml. Fourteen isolates showed the solubilisation of inorganic phosphorous ranging from 3.2 to 32.6 mg/100ml. Chitinase and HCN production was shown by 19 and 15 different isolates, respectively. In addition, genes of indole acetic acid (iaaM) and chitinase (chiC) were successively amplified from 20 and 19 isolates respectively. The two potential strains Streptomyces sp. (BPSAC34) and Leifsonia xyli (BPSAC24) were tested in vivo and improved a range of growth parameters in chilli (Capsicum annuum L.) under greenhouse conditions. This study is the first published report that actinomycetes can be isolated as endophytes from within these plants and were shown to have antagonistic and plant growth promoting abilities. These results clearly suggest the possibility of using endophytic actinomycetes as bioinoculant for plant growth promotion, nutrient mobilization or as biocontrol agent against fungal phytopathogens for sustainable agriculture.
Endophytic actinobacteria play an important role in growth promotion and development of host plant by producing enormous quantities of novel bioactive natural products. In the present investigation, ...169 endophytic actinobacteria were isolated from endospheric tissues of Rhynchotoechum ellipticum. Based on their antimicrobial potential, 81 strains were identified by 16rRNA gene analysis, which were taxonomically grouped into 15 genera. All identified strains were screened for their plant growth promoting attributes and, for the presence of modular polyketide synthases (PKSI, PKSII and nonribosomal peptide synthetase (NRPS) gene clusters to correlate the biosynthetic genes with their functional properties. Expression studies and antioxidant potential for four representative strains were evaluated using qRT-PCR and DPPH assay respectively. Additionally, six antibiotics (erythromycin, ketoconazole, fluconazole, chloramphenicol, rifampicin and miconazole) and nine phenolic compounds (catechin, kaempferol, chebulagic acid, chlorogenic acid, Asiatic acid, ferulic acid, arjunic acid, gallic acid and boswellic acid) were detected and quantified using UHPLC-QqQ
-MS/MS. Furthermore, three strains (BPSAC77, 121 and 101) showed the presence of the anticancerous compound paclitaxel which was reported for the first time from endophytic actinobacteria. This study provides a holistic picture, that endophytic actinobacteria are rich bacterial resource for bioactive natural products, which has a great prospective in agriculture and pharmaceutical industries.
Herein, we reported the electromagnetic interference performance of NiFe2O4/rGO nanocomposite. In this study NiFe2O4 nanoparticles was synthesized by co-precipitation route and the magnetic ...nanoparticles were incorporated on reduced graphene oxide (rGO) using a solvothermal method. The detailed properties of synthesized materials were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), tunneling electron microscopy (TEM), Raman spectroscopy, vibrating sample magnetometer (VSM) system, and vector network analyzer (VNA). The electromagnetic interference (EMI) shielding property of composite materials was investigated in the 8.2–12.4 GHz (X-band) frequency region. The results depicted the significant dielectric and magnetic loss in the nanocomposite as compared to rGO. Consequently, composite has improved impedance matching characteristics, which required for high electromagnetic wave absorption. Moreover, the study showed that shielding effectiveness further improves with increasing nanoparticles concentration in nanocomposite, which is due to increased interconnected network between NiFe2O4 and rGO. Furthermore, total shielding effectiveness (SET) of (35/65) NiFe2O4/rGO nanocomposite of thickness 2 mm is 38.2 dB at 10.8 GHz, which is higher than the accompanying investigated sample. It could be inferred that the redeeming properties of high dielectric and magnetic loss, enhanced absorption and multiple reflections of (35/65) NiFe2O4/rGO nanocomposite resulted in high shielding effectiveness. Therefore, this result mean that NiFe2O4/rGO nanocomposite is a promising shielding material for application in microwave absorption appliances.
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