DIRECT TORQUE CONTROL FOR DOUBLY FED INDUCTION MACHINE-BASED WIND TURBINES UNDER VOLTAGES DIPS AND WITHOUT CROWBAR PROTECTION

This letter proposes a rotor flux amplitude reference generation strategy for doubly fed induction machine based wind turbines. It is specially designed to address perturbations, such as voltage dips, keeping controlled the torque of the wind turbine, and considerably reducing the stator and rotor over currents during faults. In addition, a direct torque control strategy that provides fast dynamic response accompanies the overall control of the wind turbine. Despite the fact that the proposed control does not totally eliminate the necessity of the typical crowbar protection for this kind of turbines, it eliminates the activation of this protection during low voltage dip

Contrasting seed biology of two ornamental palms: Pygmy Date Palm (Phoenix roebelenii O’Brien) and Fishtail Palm (Caryota urens L.) and implications for their long-term conservation

477-484The Arecaceae family includes palm trees of economic importance both as a source of agricultural produce and as ornamental components in landscaping projects. Pygmy date palm (Phoenix roebelenii) and solitary fishtail palm (Caryota urens) are well known landscaping plants today. Both species have their origin in Southeast Asia and, especially C. urens is widespread in peninsular India and Sri Lanka. They are multipurpose species with a variety of applications and thus very heavily utilized. Knowledge of palm seed storage biology will improve their conservation prospects. In present studies, fresh seed moisture content in P. roebelenii was recorded to be 30% with germinability of 98%. After desiccation to 8% moisture germinability was reduced to 90% and the seeds survived cryo-exposure. Fresh seeds of C. urens, with initial moisture content of 34% and 95% germinability could be desiccated to lowest level of only 29% moisture content, with complete loss of germinability. Fresh as well as desiccated seeds of this species did not survive cryo-exposure. While the seeds of C. urens stored at room temperature lost their germinability by 110 days, seeds of P. roebelenii could germinate even after 9 months of storage. P. roebelenii is proven to exhibit orthodox seed storage behaviour while C. urens is found to exhibit recalcitrant seed storage behaviour. Long-term ex situ cryo-conservation in the form of seed gene banks would be suitable for seed propagated orthodox palm species and a few germplasm centres may be established for recalcitrant Indian palms in suitable bio-geographic regions as a complimentary ex situ conservation

Microstructure and mechanical properties of electron beam welded dissimilar steel to Fe-Al alloy joints

Electron beam welding (EBW) technique was used to perform dissimilar joining of plain carbon steel to Fe-7%Al alloy under three different weld conditions such as with beam oscillation, without beam oscillation and at higher welding speed. The effect of weld parameters on the microstructure and mechanical properties of dissimilar joints was studied using optical microscopy, SEM, EBSD, hardness, tensile and erichsen cup tests. Microstructure results show that the application of beam oscillation resulted in uniform and homogeneous microstructure compared to without beam oscillations and higher welding speed. Further, it was observed that weld microstructure changes from equiaxed to columnar grains depending on the weld speed. High weld speed results in columnar grain structure in the weld joint. Erichsen cup test results show that the application of beam oscillation results in excellent formability as compared to high weld speed. Tensile test results show no significant difference in strength properties in all three weld conditions, but the ductility was found to be highest for joints obtained with the application of weld beam oscillation as compared to without beam oscillation and high weld speed. This study shows that the application of beam oscillations plays an important role in improving the weld quality and performance of EBW dissimilar steel to Fe-Al joints

Framework Guidlines and Governance for Designing Local Adaptation Plan of Action to Mainstream Climate Smart Villages in India

Based on the extensive review of existing frameworks and practices on climate change adaptation and authors experiences in Indian context, this study presented BRIFFS (bottom-up, responsive, inclusive, flexible, forward-looking, and sustainable) as the major guidelines for developing LAPA. This study presented the major steps of LAPA with clear actions, activities and also tools that can be used in each step. The nine steps of LAPA are as follows: 1) Communicating climate change risks and adaptation measures at local level, 2) Assessment of climate risks and vulnerabilities and scoping of adaptation actions, 3) Prioritisation of adaptation options, 4) Formulation of LAPA, 5) LAPA integration in planning process, 6) Institutional arrangement to implement LAPA, 7) Implementation of LAPA, 8) Progress assessment of LAPA, and 9) Feedback and revision of LAPA

Antimicrobial activity of leaf extracts of Indian medicinal plants against clinical and phytopathogenic bacteria

The ethnobotanical efficacy of Indian medicinal plants; Achyranthes aspera, Artemisia parviflora, Azadirachta indica, Calotropis gigantean, Lawsonia inermis, Mimosa pudica, Ixora coccinea, Parthenium hysterophorus and Chromolaena odorata were examined using agar disc diffusion method against clinical bacteria (Escherichia coli and Staphylococcus aureus) and phytopathogenic bacteria (Xanthomonas vesicatoria and Ralstonia solanacearum). Leaves were extracted using different solvents such as methanol, ethanol, ethyl acetate and chloroform. Among treatments, maximum in vitro inhibition was scored in methanol extracts of C. odorata which offered inhibition zone of 10, 9, 12 and 12 mm against E. coli, S. aureus, X. vesicatoria and R. solanaccearum, respectively, followed by chloroform extract of the same plant leaf with inhibition zone of 8, 4, 4 and 4 mm, respectively. A significant inhibition of E. coli was found in aqueous and in all tested solvent extracts of A. indica. In case of S. aureus, maximum inhibition of 8 mm was obtained in aqueous extracts of A. indica and 6 mm from methanol extract of L. inermis. The minimum inhibitory concentration (MIC) value for the clinicalbacteria ranged between 0.35 to 4.0 mg/ml and 0.25 to 4.0 mg/ml for phytopathogenic bacteria when tested with all four solvents extracts of C. odorata. Whereas, extracts of A. aspera, A. parviflora, C. gigantean, L. inermis, M. pudica and I. coccinea were found to be ineffective or showed poor inhibition on tested human and phytopathogenic bacteria

High performance non-doped green organic light emitting diode via delayed fluorescence

P. G. thanks the Science & Engineering Research Board (SERB), India, for the Start-up Research Grant (SRG) (Grant No: SRG/2020/000161). E.Z-C. thanks the Engineering and Physical Sciences Research Council (EPSRC) EP/P010482/1 for support. P. R. thanks the Indian Institute of Science (IISc) for generous financial support and the Science & Engineering Research Board (SERB), India, for the SERB-Power Grant (SPG) (Grant No: SPG/2020/000107). B.S. thank IISc for the C. V. Raman Fellowship under the Institute of Eminence (IoE).Non-doped, delayed fluorescence organic light-emitting diodes (OLEDs) provide a route to high performance devices and simplified device fabrication. Here, two ambipolar anthracene derivatives containing a hole-transporting di-p-tolylamine and a carbazole and an electron-transporting phosphine oxide moiety are rationally designed and synthesized. The thermal and optoelectronic properties were investigated and the neat films of these compounds show high photoluminescence quantum yields of 84–87%. Non-doped OLEDs with these luminogens exhibit green emission at ∼545 nm and an EQEmax of over 7.2% due to the delayed fluorescence resulting from triplet–triplet annihilation (TTA). The devices show a high luminance of over 104 400 cd m−2. Power efficiency and current efficiency maxima are up to 23.0 lm W−1 and 28.3 cd A−1, respectively. Moreover, the devices show very low efficiency roll-off and retain 90% of the maximum efficiency even at 20 000 cd m−2. When combined with a thermally activated delayed fluorescent (TADF) assistant dopant, the green-emitting OLEDs show a high EQEmax of 17.8%.PostprintPeer reviewe

Quality-of-service-centric design and analysis of unmanned aerial vehicles

Recent years have witnessed rapid development and great indignation burgeoning in the unmanned aerial vehicles (UAV) field. This growth of UAV-related research contributes to several challenges, including inter-communication from vehicle to vehicle, transportation coverage, network information gathering, network interworking effectiveness, etc. Due to ease of usage, UAVs have found novel applications in various areas such as agriculture, defence, security, medicine, and observation for traffic-monitoring applications. This paper presents an innovative drone system by designing and developing a blended-wing-body (BWB)-based configuration for next-generation drone use cases. The proposed method has several benefits, including a very low interference drag, evenly distributed load inside the body, and less radar signature compared to the state-of-the-art configurations. During the entire procedure, a standard design approach was followed to optimise the BWB framework for next-generation use cases by considering the typically associated parameters such as vertical take-off and landing and drag and stability of the BWB. Extensive simulation experiments were performed to carry out a performance analysis of the proposed model in a software-based environment. To further confirm that the model design of the BWB-UAV is fit to execute the targeted missions, the real-time working environments were tested through advanced numerical simulation and focused on avoiding cost and unwanted wastages. To enhance the trustworthiness of this said computational fluid dynamics (CFD) analysis, grid convergence test-based validation was also conducted. Two different grid convergence tests were conducted on the induced velocity of the Version I UAV and equivalent stress of the Version II UAV. Finite element analysis-based computations were involved in estimating structural outcomes. Finally, the mesh quality was obtained as 0.984 out of 1. The proposed model is very cost-effective for performing a different kind of manoeuvring activities with the help of its unique design at reasonable mobility speed and hence can be modelled for high-speed-based complex next-generation use cases

Ocular injuries in survivors of improvised explosive devices (IED) in commuter trains

<p>Abstract</p> <p>Background</p> <p>Ocular injuries are common in survivors of terror incidents that involve the use of explosive materials. These explosives are commonly of a High Explosive type (HE) and may be fashioned into improvised explosive devices (IED) that incorporate additional materials to maximise trauma and injuries. Serial IED explosions have occurred in commuter trains in several cities including London and Madrid but data on ocular injuries is limited. We report the ocular injuries of the survivors of a series of IED explosions in crowded commuter trains.</p> <p>Methods</p> <p>28 patients (56 eyes, 28 male, ages ranging from 22 to 52 years (mean 35.27 years) were screened in the triage area or the Intensive Care Unit (ICU). Testing included bedside visual acuity testing, torchlight examination of the anterior segment and dilated (or if necessary, undilated) fundus examination. Selected patients underwent B-scan examination, magnetic resonance imaging of the brain, orbits and the optic nerves or visual evoked potential assessment. The injuries, investigations and procedures were entered into the patient's case sheet as well as into a standardised format suggested by the Indian eye injury registry (IER).</p> <p>Results</p> <p>16 of 28 patients (57.1%) had ocular injuries whereas 12 (42.8%) were found to be normal. Injuries were seen unilaterally in 10 patients and bilaterally in six yielding a total of 22 injured eyes. The common injuries were periorbital haemorrhages (09 eyes, 40%); first or second degree burns to the upper or lower lids (seen in 07 eyes, 31.8 %) and corneal injuries (seen in 08 eyes, 36.3%). Open globe injuries were seen in two eyes of two patients (09%). One patient (4.5%) had a traumatic optic neuropathy.</p> <p>Conclusion</p> <p>Ophthalmologists and traumatologists should be aware of these patterns of ocular injuries. Protocols need to include the screening of large numbers of patients in a short time, diagnostic tests (B scan, visual evoked potential (VEP) etc) and early surgery preferably at the initial triage itself as most of the serious injuries in our studies had been missed or not treated at an initial assessment.</p

Potential of optimized NOvA for large theta(13) & combined performance with a LArTPC & T2K

NOvA experiment has reoptimized its event selection criteria in light of the recently measured moderately large value of theta(13). We study the improvement in the sensitivity to the neutrino mass hierarchy and to leptonic CP violation due to these new features. For favourable values of deltacp, NOvA sensitivity to mass hierarchy and leptonic CP violation is increased by 20%. Addition of 5 years of neutrino data from T2K to NOvA more than doubles the range of deltacp for which the leptonic CP violation can be discovered, compared to stand alone NOvA. But for unfavourable values of deltacp, the combination of NOvA and T2K are not enough to provide even a 90% C.L. hint of hierarchy discovery. Therefore, we further explore the improvement in the hierarchy and CP violation sensitivities due to the addition of a 10 kt liquid argon detector placed close to NOvA site. The capabilities of such a detector are equivalent to those of NOvA in all respects. We find that combined data from 10 kt liquid argon detector (3 years of nu + 3 years of nubar run), NOvA (6 years of nu + 6 years of nubar run) and T2K (5 years of nu run) can give a close to 2 sigma hint of hierarchy discovery for all values of deltacp. With this combined data, we can achieve CP violation discovery at 95% C.L. for roughly 60% values of deltacp.Comment: 22 pages, 24 pdf figures, 5 tables. In the appendix, new results are presented with conservative choices of central values of oscillation parameters. New references are added. Accepted in JHE

A Wideband Multi Segment Dielectric Resonator Antenna

The present work deals with the design of a wideband multi segment dielectric resonator antenna (DRA) that can be used for various applications.The proposed antenna resonates at a tri-band frequencies of 8.48GHz, 16.8GHz and 23.95GHz giving an impedence bandwidth of 62.99%.The tri-band DRA is excited by a coaxial-cable-feed