Experimental evaluation of matrix converter for wind energy conversion system under various abnormal conditions

This paper presents the experimental evaluation of reversed indirect matrix converter (MC) interfaced wind energy conversion system (WECS), where space vector pulse width modulation together with adaptive fuzzy logic control is effectively used to enhance the performance of system under various abnormal conditions like abrupt change in wind speed, disconnection from grid, misfire in the converter, sudden out of one phase, change in load etc. The proposed adaptive control system is realized using dSPACE DS1104 board. Selective experimental results are presented using a laboratory 1.2 kW prototype of WECS to demonstrate the resulting improvements of the developed system under abnormal conditions.http://www.ijrer.org/ijrer/index.php/ijreram201

Embracing drones and the Internet of drones systems in manufacturing – An exploration of obstacles

The manufacturing sector attributes the growing prominence of Drones and the Internet of Drones (IoD) systems to their multifaceted utility in delivery, process monitoring, infrastructure inspection, inventory management, predictive maintenance, and safety inspections. Despite their potential benefits, adopting these technologies faces significant obstacles that need systematic identification and resolution. The current literature inadequately addresses the barriers impeding the adoption of Drones and IoD systems in manufacturing, indicating a research gap. This study bridges this gap by providing comprehensive insights and facilitating the organisational transition towards embracing Drone and IoD technologies. This research identifies 20 critical barriers to deploying Drones and IoD in manufacturing. These barriers are validated through a global quantitative survey of 120 Drone experts and analysed via Exploratory Factor Analysis (EFA). EFA categorises these challenges into six distinct dimensions. Utilising the Analytical Hierarchy Process (AHP), these dimensions and individual barriers are ranked, incorporating feedback from five Drone specialists. The study highlights ‘Safety and Human Resource Barriers’ and ‘Payload Capacity and Battery Barriers’ as the most predominant obstacles. Key concerns include limited battery life, explosion risks, and potential damage to assets and individuals. This research significantly advances the existing literature by presenting a practical methodology for categorising and prioritising Drone and IoD adoption barriers. Employing EFA and AHP offers a globally relevant framework for stakeholders to strategically address these challenges, advancing the integration of drones and IoD systems in the manufacturing domain

Influence of a classical homogeneous gravitational field on dissipative dynamics of the Jaynes-Cummings model with phase damping

In this paper, we study the dissipative dynamics of the Jaynes-Cummings model with phase damping in the presence of a classical homogeneous gravitational field. The model consists of a moving two-level atom simultaneously exposed to the gravitational field and a single-mode traveling radiation field in the presence of the phase damping. We present a quantum treatment of the internal and external dynamics of the atom based on an alternative su(2) dynamical algebraic structure. By making use of the super-operator technique, we obtain the solution of the master equation for the density operator of the quantum system, under the Markovian approximation. Assuming that initially the radiation field is prepared in a Glauber coherent state and the two-level atom is in the excited state, we investigate the influence of gravity on the temporal evolution of collapses and revivals of the atomic population inversion, atomic dipole squeezing, atomic momentum diffusion, photon counting statistics and quadrature squeezing of the radiation field in the presence of phase damping.Comment: 25 pages, 15 figure

Leveraging antibacterial efficacy of silver loaded chitosan nanoparticles on layer-by-layer self-assembled coated cotton fabric

The present study relates to forma self-assembled coating on cotton fabric using layer-by-layer (L-B-L) technique to impart antimicrobial property. Poly(styrenesulfonate) (PSS) and synthesised silver loaded chitosan (CS-Ag) nanoparticles were used as anionic and cationic agents, respectively, for the L-B-L electrostatic assembly of polyelectrolytes. The alternate L B-L deposition of PSS and CS-Ag nanoparticles on fabric was done up to 15 bi-layers, which was confirmed by measuring the change in depth of colour of fabric after each single layer deposition. Scanning electron micrographs showed the successful deposition of CS-Ag nanoparticles as the topmost surface layer of coated fabric, which was further reaffirmed by X ray photoelectron spectroscopy analysis. Results of both qualitative and quantitative analysis showed enhancement in the antibacterial activity of fabric coated L-B-L with CS-Ag nanoparticles (using minimal loading of silver) with respect to that of fabric coated L-B-L with chitosan (CS) nanoparticles. This was further substantiated by sustained release of Ag+ from fabric coated L-B-L with CS-Ag nanoparticles, as observed by atomic absorption spectroscopy. Besides, no adverse effect on the physical and mechanical properties of the fabric, such as air-permeability, tensile strength and bending (flexural) rigidity, was observed after L-B-L coating of nanoparticles

Effects of short-term exposure to naturally occurring thymol concentrations on transmission of a bumble bee parasite

Background: Plants produce antimicrobial phytochemicals that can reduce growth and infectivity of parasites in animals. Pollinator parasites are transmitted between hosts that forage on shared flowers. Floral transmission directly exposes parasites to phytochemicals on floral surfaces and in nectar, both at flowers and, post-ingestion, in the crop. This exposure could directly affect parasite transmission to new hosts. Approach: We combined nectar chemical analyses with field and cell culture experiments to test effects of the floral phytochemical thymol on transmission potential of the trypanosomatid gut parasite Crithidia in Bombus impatiens. First, we measured thymol concentrations in Thymus vulgaris nectar. Second, we tested how addition of thymol to floral nectaries affected parasite transmission to foraging bees. Third, we used cell cultures to determine direct, dose-dependent effects of short term thymol exposure on subsequent in vitro parasite growth. Results: We found 26.1 ppm thymol in Thymus vulgaris nectar, 5-fold higher than previously documented in this species. However, addition of thymol to flowers of parasite-inoculated inflorescences of four plant species did not affect acquisition of Crithidia infection during a foraging bout. Cell culture experiments showed that thymol concentrations needed to reduce subsequent Crithidia growth by 50% (120 ppm) were 4.6-fold higher than the highest detected nectar concentration. Conclusions: Although thymol exposure can influence Crithidia viability, Crithidia are robust to the duration and magnitude of exposure encountered during floral foraging under natural conditions. Our experiments suggest that any effects of thymol alone on Crithidia-host infection dynamics probably reflect indirect, possibly host-mediated, effects of chronic thymol ingestion

Evaluation of global composite collection reveals agronomically superior germplasm accessions for chickpea improvement

The rich genetic diversity existing within exotic, indigenous, and diverse germplasm lays the foundation for the continuous improvement of crop cultivars. The composite collection has been suggested as a gateway to identifying superior germplasm for use in crop improvement programs. Here, a chickpea global composite collection was evaluated at five locations in India over two years for five agronomic traits to identify agronomically superior accessions. The desi, kabuli, and intermediate types of chickpea accessions differed significantly for plant height (PLHT) and 100-seed weight (100 SW). In contrast, the intermediate type differed substantially from kabuli for days to maturity (DM). Several highly significant trait correlations were detected across different locations. The most stable and promising accessions from each of the five locations were prioritised based on their superior performance over the best-performing check cultivar. Accordingly, the selected germplasm accessions of desi type showed up to 176% higher seed yield (SY), 29% lower flowering time, 21% fewer maturity days, 64% increase in PLHT, and 183% larger seeds than the check cultivar JG11 or Annigeri. The prioritised kabuli accessions displayed up to 270% more yield, 13% less flowering time, 8% fewer maturity days, 111% increase in PLHT, and 41% larger seeds over the check cultivar KAK2. While the intermediate type accessions had up to 169% better yield, 1% early flowering, 3% early maturity, 54% taller plants, and 25% bigger seeds over the check cultivar JG 11 or KAK2. These accessions can be utilised in chickpea improvement programs to develop high-yielding, early flowering, short duration, taller, and large-seeded varieties with a broad genetic base

A Conformally Invariant Holographic Two-Point Function on the Berger Sphere

We apply our previous work on Green's functions for the four-dimensional quaternionic Taub-NUT manifold to obtain a scalar two-point function on the homogeneously squashed three-sphere (otherwise known as the Berger sphere), which lies at its conformal infinity. Using basic notions from conformal geometry and the theory of boundary value problems, in particular the Dirichlet-to-Robin operator, we establish that our two-point correlation function is conformally invariant and corresponds to a boundary operator of conformal dimension one. It is plausible that the methods we use could have more general applications in an AdS/CFT context.Comment: 1+49 pages, no figures. v2: Several typos correcte

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02