Induction Factor Research Articles

An Induction Curve Model for Prediction of Power Output of Wind Turbines in Complex Conditions

Power generation from wind farms is traditionally modeled using power curves. These models are used for assessment of wind resources or for forecasting energy production from existing wind farms. However, prediction of power using power curves is not accurate since power curves are based on ideal uniform inflow wind, which do not apply to wind turbines installed in complex and heterogeneous terrains and in wind farms. Therefore, there is a need for new models that account for the effect of non-ideal operating conditions. In this work, we propose a model for effective axial induction factor of wind turbines that can be used for power prediction. The proposed model is tested and compared to traditional power curve for a 2.5 MW horizontal axis wind turbine. Data from supervisory control and data acquisition (SCADA) system along with wind speed measurements from a nacelle-mounted sonic anemometer and turbulence measurements from a nearby meteorological tower are used in the models. The results for a period of four months showed an improvement of 51% in power prediction accuracy, compared to the standard power curve.

Development and assessment of a blade element momentum theory model for high solidity vertical axis tidal turbines

Tidal energy is an attractive renewable resource given its predictability. The production of reliable, efficient and cost-effective tidal energy turbines requires the development of computer models for assessment and design optimisation of turbine performance. Blade element momentum theory (BEMT) models are attractive to turbine designers as they have a very low computational cost compared to CFD models. In this paper, we develop a BEMT model for high solidity and highly loaded vertical axis tidal turbine rotors which traditional BEMT models are incapable of modelling. The double multiple stream-tube model employs a graphical approach for determination of axial induction factors rather than the iterative approach used in traditional BEMT models. Corrective methods to account for dynamic stall, flow expansion, and finite aspect ratios are also implemented in the model. Model performance is assessed against experimentally measured power performance data of both low and high solidity rotors. The model reproduced peak efficiency values to within 2.5% for a low solidity wind turbine, 8% for a high solidity wind turbine and to within 10% for a high solidity tidal turbine in confined flow.

A Comprehensive Transcriptome-Wide Identification and Screening of WRKY Gene Family Engaged in Abiotic Stress in Glycyrrhiza glabra

The study reports 147 full-length WRKY genes based on the transcriptome analysis of Glycyrrhiza genus (G. glabra and G. uralensis). Additional motifs in G. glabra included DivIVA (GgWRKY20) and SerS Superfamily (GgWRKY21) at the C-terminal, and Coat family motifs (GgWRKY55) at the N-terminal of the proteins, while Exo70 exo cyst complex subunit of 338 amino acid (GuWRKY9) was present at the N-terminal of G. uralensis only. Plant Zn cluster super-family domain (17 WRKYs) and bZIP domain (2 WRKYs) were common between the two species. Based on the number of WRKY domains, sequence alignment and phylogenesis, the study identified GuWRKY27 comprising of 3 WRKY domains in G. uralensis and a new subgroup-IIf (10 members), having novel zinc finger pattern (C-X4-C-X22-HXH) in G. glabra. Multiple WRKY binding domains (1–11) were identified in the promoter regions of the GgWRKY genes indicating strong interacting network between the WRKY proteins. Tissue-specific expression of 25 GgWRKYs, under normal and treated conditions, revealed 11 of the 18 induction factor triggered response corroborating to response observed in AtWRKYs. The study identified auxin-responsive GgWRKY 55 & GgWRKY38; GA3 responsive GgWRKYs15&59 in roots and GgWRKYs8, 20, 38, 57 &58 in the shoots of the treated plant. GgWRKYs induced under various stresses included GgWRKY33 (cold), GgWRKY4 (senescence), GgWRKYs2, 28 & 33 (salinity) and GgWRKY40 (wounding). Overall, 23 GgWRKYs responded to abiotic stress, and 17 WRKYs were induced by hormonal signals. Of them 13 WRKYs responded to both suggesting inter-connection between hormone signalling and stress response. The present study will help in understanding the transcriptional reprogramming, protein-protein interaction and cross-regulation during stress and other physiological processes in the plant.

Design and Optimization of Wind Turbine with Axial Induction Factor and Tip Loss Corrections

The aerodynamic modeling of an HAWT (horizontal axis wind turbine) is an essential step in the design of this machine. Generally, the Blade Element Momentum theory (BEM) theory is used. It consists of combining Momentum theory and Blade Element Momentum theory, which makes it possible to solve the equations of aerodynamic forces by an iterative method. This method does not lead to a concordance with the experience. Several studies have tried to introduce corrections to improve the model. The purpose of this study is the design of wind turbine blade by taking into account the corrections of the axial and tangential induction factors. To that end, an iterative method based on Blade Element Momentum theory (BEM) is used and simulations are conducted for NACA airfoil with 5-digit. The study examined blade constructed with only one profile, and blade constructed with two different profiles. Their aerodynamic forces were compared and were shown to increase with the use of the blade built with two different profiles ( NACA63421+NACA63215).

AntagomiR-199a Enhances the Liver Protective Effect of Hypoxia-Preconditioned BM-MSCs in a Rat Model of Reduced-Size Liver Transplantation.

Reduced-size liver transplantation (LT) was invented to overcome the shortage of donor livers; however, it has proven to be more susceptible to ischemia-reperfusion injury. Bone marrow-derived mesenchymal stem cell infusion has been shown to be protective following LT. Optimization of MSC infusion has been performed, among which hypoxia preconditioning and miRNA modulation have shown promise. MiR-199a inhibition was reported to induce angioneogenesis; however, whether mir-199a inhibition enhances the protective effect of Bone marrow-derived mesenchymal stem cells in LT remains unknown. In this study, we combined antagomiR-199a with hypoxia-preconditioned MSC (H-MSC) infusion to discuss their effect and mechanism in a rat model of reduced-size LT. A reduced-size LT model was constructed and H-MSCs were intraportally injected during operation. AgomiR-199a and antagomir-199a were injected through the caudal vein once a day after LT. The level of apoptosis and proinflammatory cytokines were measured. An anti-vascular endothelial growth factor (VEGF) antibody was injected to further explore the underlying mechanism. AntagomiR-199a plus H-MSC not only significantly decreased ALT and AST 72 h after LT but also ameliorated the level of apoptosis and inhibited inflammatory reactions. On the contrary, agomir-199a reduced the protective effect of the H-MSC infusion. In terms of mechanism, the liver protective effect of miR-199a inhibition was abolished by treatment with a VEGF-neutralizing antibody. AntagomiR-199a enhanced the protective effect of H-MSCs infusion via activation of the hypoxia induction factor 1α/VEGF axis.

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The ducted tidal turbine models have been developed to utilize convertion of the kinetic energy on ocean currents. The research on refining the turbine characteristics has been carried out by modifying the turbine’s shape and size. The study of the duct diameter ratio effect on the energy characteristics of the turbine was done in this work. This study was conducted by modifying the duct diameter ratio ( ) with the constant inlet diameter D 0 and outlet D 2 . The flow conditions are analyzed for five cases of turbines with different shapes and diameters to determine the optimum conditions. The optimum value of the diameter ratio could be obtained at the maximum value of power coefficient C P . Flow velocity in the ducted turbine was measured at three turbine sections, namely; the inlet section, the impeller housing section, and the outlet section. The measurement of flow in turbines was carried out at the free stream velocity U 0 = 1,5 m/s. The power coefficient C P and thrust coefficient C T were calculated based on flow velocity data on the turbine cVennell sections for each case. The power coefficient C P reaches the maximum value (Betz limit) at the resistance coefficient K = 2 and the value of axial induction factor a = 0,37. These values were founded at diameter ratio d=0,66. The value of thrust coefficient C T reaches the maximum value at K = 3,9, a = 0,53 and . The optimum value of the diameter ratio was founded at d=0,69.

Implementation of the BEM skewed-wake model within the multibody aero-elastic solver Cp-Lambda

To account for the problem of an azimuthally constant induction in the BEM method, which influences on incorrectly predicted aerodynamic loads in the yawed flow, a skewed-wake model implementation to the BEM method has been performed. The numerical aerodynamic loads have been compared with the wind tunnel data of the NREL Phase VI and against another numerical campaign. At first, the model predictions have been validated against experimental data performed with aligned flow conditions, showing a reasonable match. Successively, the model predictions are validated against experimental results obtained with the wind turbine yawed. Results show, a possible better prediction of loads at yawed flow with Skewed-Wake correction, however the method does not overall correlate better, compared to the BEM method with implemented local variability of the induction factor.

A qualitative study on perceptions of doping induction factors among elite athletes

A qualitative study on perceptions of doping induction factors among elite athletes

Investigation of pneumococcal virulence factors in the infection process

This review summarizes current knowledge regarding the pathological mechanism of Streptococcus pneumoniae, a major cause of pneumonia, sepsis, and meningitis, with focus on our previously presented studies.To identify pneumococcal adhesins or invasins on cell surfaces, we investigated several proteins with an LPXTG anchoring motif and identified one showing interaction with human fibronectin, which was designated PfbA. Next, the mechanism of pneumococcal evasion form host immunity system in blood was examined and pneumococcal α-Enolase was found to function as a neutrophil extracellular trap induction factor. Although S. pneumoniae organisms are partially killed by iron ion-induced free radicals, they have an ability to invade red blood cells and then evade antibiotics, neutrophil phagocytosis, and H2O2 killing. In addition, our findings have indicated that zinc metalloprotease ZmpC suppresses pneumococcal virulence by inhibiting bacterial invasion of the central nervous system. Since evolutionarily conserved virulence factors are potential candidate therapeutic targets, we performed molecular evolutionary analyses, which revealed that cbpJ had the highest rate of codons under negative selection to total number of codons among genes encoding choline-binding proteins. Our experimental analysis results indicated that CbpJ functions as a virulence factor in pneumococcal pneumonia by contributing to evasion of neutrophil killing.Use of a molecular biological approach based on bacterial genome sequences, clinical disease states, and molecular evolutionary analysis is an effective strategy for revealing virulence factors and important therapeutic targets.

Chondrogenic activity of two herbal products; pomegranate fruit extract and avocado/soybean unsaponifiable.

Background and purpose:Articular cartilage defects aren’t repaired by itself. Numerous studies have been conducted in the area of cartilage tissue engineering and some of them considered herbal products. An attempt was made in this study to compare the effects of pomegranate fruit extract (PFE), avocado/soybean unsaponifiable (ASU), and their equal proportional mixture on the chondrogenesis of human adipose-derived stem cells (hADSCs).Experimental approach:PFE was prepared through the percolation method. ASU powder was dissolved in ethanol at 10 μg/mL concentration and was sterilized. The hADSCs first were isolated, expanded in monolayer culture and identified, and next seeded on fibrin scaffolds. The hADSCs/fibrin scaffolds were divided into 4 groups of control, ASU, PFE, and PFE+ ASU and subjected to in vitro induction for 2 weeks. The control group received chondrogenic medium, other groups received chondrogenic medium plus ASU, PFE, or PFE + ASU, respectively. The MTT assay was performed for cell viability evaluation, real-time polymerase chain reaction for expression of cartilage genes, and the toluidine blue, safranin-O, and immunohistochemistry for staining of the constructs.Findings / Results:Cell viability, cartilage genes expression, matrix staining density, and collagen II protein levels in PFE samples were significantly higher than those of the other groups (P < 0.05). Histological assessments revealed more chondrogenic centers (P < 0.05) in the PFE group compared to the other groups.Conclusion and implications:In this study, it was revealed that PFE can be considered as an induction factor for future chondrogenic studies.

Induction, detection, formation, and resuscitation of viable but non-culturable state microorganisms.

The viable but nonculturable (VBNC) state has been recognized as a strategy for bacteria to cope with stressful environments; in this state, bacteria fail to grow on routine culture medium but are actually alive and can resuscitate into a culturable state under favorable conditions. The VBNC state may pose a great threat to food safety and public health. To date, more than 100 VBNC microorganism species have been proven to exist in fields of food safety, environmental application, and agricultural diseases. Most harsh conditions can induce these microorganisms into the VBNC state, including food processing and preservation methods, adverse environmental conditions, and plant-disease controlling means. The characteristics of VBNC state cells differ from those of normally growing cells and dead cells, based on which of the various detection methods are developed, and they are of great significance for potential risk assessment. To provide molecular level insights into this state, many studies on induction and resuscitation mechanisms have emerged over the past three decades, including research on omics, specific genes, or proteins involved in VBNC state formation and the roles of promoters in resuscitation from the VBNC state. In this review, microorganism species, induction and resuscitation factors, detection methods, and formation and resuscitation mechanisms of the VBNC state are comprehensively and systematically summarized.

A double-multiple streamtube model for vertical axis wind turbines of arbitrary rotor loading

Abstract. We introduce an improved formulation of the double-multiple streamtube (DMST) model for the prediction of the flow quantities of vertical axis wind turbines (VAWT). The improvement of the new formulation lies in that it renders the DMST valid for any induction factor, i.e., for any combination of rotor solidity and tip speed ratio. This is done by replacing the Rankine–Froude momentum theory of the DMST, which is invalid for moderate and high induction factors, with a new momentum theory recently proposed, which provides sensible results for any induction factor. The predictions of the two DMST formulations are compared with VAWT power measurements obtained at Princeton's High Reynolds number Test Facility, over a range of tip speed ratios, rotor solidities, and Reynolds numbers, including those experienced by full-scale turbines. The results show that the new DMST formulation demonstrates a better overall performance, compared to the conventional one, when the rotor loading is moderate or high.

Evaluating the cytocompatibility and differentiation of bone progenitors on electrospun zein scaffolds.

Bone fractures often result in complications that require surgical intervention to promote fracture healing. Tissue engineering seeks to alleviate the need for autologous bone grafting by utilizing scaffolds that can promote bone fracture healing. Plant-derived materials are desirable biomaterials because of their biodegradability, availability, and low immunogenicity. Among various plant-derived proteins, zein, which is a corn protein, has shown promise for bone repair. However, when processed, zein is often blended with synthetic materials to improve mechanical properties and overall hydrolytic stability. In this study, pure zein was electrospun to create fibrous scaffolds and cross-linked with trimethylolpropane triglycidyl ether to improve hydrolytic stability. Scaffolds were characterized and evaluated in vitro for promoting the osteogenic differentiation of MC3T3-E1 cells, which are bone progenitor cells. Cross-linked zein scaffolds retained their uniform fiber morphologies after hydration. MC3T3-E1 cells grew and differentiated on the zein scaffolds even in the absence of induction factors, as demonstrated by increased alkaline phosphatase activity, mineralization, and early upregulation of Runx2 gene expression, a transcription factor associated with osteoblast differentiation. These studies demonstrate that stable, zein fibrous scaffolds could have potential for use in bone repair applications.

Development of an interface to introduce stationary LES data to the URANS solver THETA for HAWT performance prediction

AbstractThe impact of different sheared velocity profiles on the performance prediction of a horizontal axis wind turbine in the atmospheric boundary layer is investigated. Firstly, the wall roughness in the analytical logarithmic description of the atmospheric boundary layer is varied to obtain different velocity profiles. Subsequently, it is proposed to replace the analytical logarithmic description of the atmospheric boundary layer by the time‐averaged velocity data of a precursor large eddy simulation (LES) and to reconstruct the turbulence of the velocity fluctuations. The LES data are introduced as inflow condition through a LES‐RANS interface in a one‐way coupling approach. Three different methods to reconstruct URANS turbulence values out of the velocity fluctuations are investigated. It is shown that the reconstruction method has an impact on the development of the velocity profile, turbulent kinetic energy, and the turbulent dissipation during the transport through the URANS domain. The different inflow data, which the horizontal axis wind turbine experiences, are responsible for changes in the overall rotor thrust (up to 2.7%) and rotor torque (up to 2.4%). Conversely, the induction factors and effective angles of attack hardly change and can well be compared with a blade element momentum method. Finally, the results of both approaches to prescribe the atmospheric boundary layer are compared. The thrust and power coefficients, and wake recovery are close to each other. Simulations are carried out on an industrial 900 kW wind turbine with the incompressible URANS solver THETA.

System-level design studies for large rotors

Abstract. We examine the effect of rotor design choices on the power capture and structural loading of each major wind turbine component. A harmonic model for structural loading is derived from simulations using the National Renewable Energy Laboratory (NREL) aeroelastic code FAST to reduce computational expense while evaluating design trade-offs for rotors with radii greater than 100 m. Design studies are performed, which focus on blade aerodynamic and structural parameters as well as different hub configurations and nacelle placements atop the tower. The effects of tower design and closed-loop control are also analyzed. Design loads are calculated according to the IEC design standards and used to create a mapping from the harmonic model of the loads and quantify the uncertainty of the transformation. Our design studies highlight both industry trends and innovative designs: we progress from a conventional, upwind, three-bladed rotor to a rotor with longer, more slender blades that is downwind and two-bladed. For a 13 MW design, we show that increasing the blade length by 25 m, while decreasing the induction factor of the rotor, increases annual energy capture by 11 % while constraining peak blade loads. A downwind, two-bladed rotor design is analyzed, with a focus on its ability to reduce peak blade loads by 10 % per 5∘ of cone angle and also reduce total blade mass. However, when compared to conventional, three-bladed, upwind designs, the peak main-bearing load of the upscaled, downwind, two-bladed rotor is increased by 280 %. Optimized teeter configurations and individual pitch control can reduce non-rotating damage equivalent loads by 45 % and 22 %, respectively, compared with fixed-hub designs.

Ecotoxicity, genotoxicity, and oxidative potential tests of atmospheric PM10 particles

The aim of the present work was to investigate the likely toxicological impact of atmospheric PM10 particles by comparing different effect-based methodologies, namely the Vibrio fischeri bioluminescence inhibition bioassay to evaluate ecotoxicity, the SOS Chromotest assay to estimate genotoxicity, and the Dithiothreitol (DTT) and Ascorbic Acid (AA) acellular assays to assess oxidative potential. The chemical composition was characterized for about 30 species, to assess the potential health impact of specific chemical components. Atmospheric particles were collected from spring to summer at a coastal site of the Central Mediterranean, away from large sources of local pollution. The Toxicity Unit (TU) index, used to assess the ecotoxicity, showed that 33% of the samples were toxic. The Induction Factor (IF), generally used to assess particle's genotoxicity, varied from 0.3 to 1.5 that represents the threshold value for genotoxicity. The oxidative potential (OP) determined by the DTT and AA assay varied within the 4.9–34.5 and 4.8–140.6 nmol min−1 range, respectively. DTT-OP and TU values were significantly correlated with OC, EC, and nss-K+, likely because the DTT and Vibrio fischeri responses were mainly associated with species from combustion sources. The IF factor was significantly correlated with some metals (Al, Ba, La, P, Sr, and Ti) likely from traffic sources and did not show any significant correlation with TU and OP values. Overall, paper's results proved the episodic occurrence of ecotoxicity and genotoxicity levels in PM10 particles sampled directly from their natural environment and away from strong pollution sources, highlighting the role mainly of carbonaceous compounds and heavy metals. The impact of spurious correlations between DTT- and AA-OPV and chemical species concentration has also been addressed.

Influence of interaction between the diffuser and rotor on energy harvesting performance of a micro-diffuser-augmented hydrokinetic turbine

A way to quantified diffuser-rotor interaction is presented for a micro-diffuser-augmented hydrokinetic turbine (MDAHT) base on the actuator disc theory (Jamieson, 2011). The large eddy simulation/Reynolds-averaged Navier–Stokes model (DES) for computational fluid dynamics were employed to simulate for bare turbine, bare diffuser and diffuser-augmented turbine, respectively. The axial induction factor of bare diffuser was obtained via the average speed of the turbine center plane, and that of both bare turbine and diffuser-augmented turbine were obtained based on the computational CP and CT. The result shows that the interaction between the diffuser and rotor are corresponding to equivalent axial induction factor ai and ai + ad, which is tightly relative to diffuser shape parameters and the operational parameters. Bigger angle of attack and camber of diffusers contributes to higher positive ai and higher negative ai + ad, and more energy harvesting performance on MDAHT is acquired. Besides, angle of attack and camber of diffuser also affected the variation of the CP and CT curve. The maximum TSR point was shifted to higher TSR position with the increase of angle of attack and camber of diffuser, and the angle of attack has a larger influence on the energy harvesting performance for MDAHT comparing with the camber of diffuser. Moreover, the influences of the tip clearances and diffuser contraction ratios on energy harvesting performance versus TSRs were also investigated.

Noninvasive monitoring of bone regeneration using NaYF4: Yb3+, Er3+ upconversion hollow microtubes supporting PLGA-PEG-PLGA hydrogel

In this work, a novel injectable luminescent hydrogel composite composed of poly(l-lactide-co-glycolide)-poly(ethylene glycol)-poly(l-lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymer and NaYF4: Yb3+, Er3+ hollow microtubes was successfully prepared for noninvasive monitoring of bone regeneration. The incorporation of NaYF4: Yb3+, Er3+ hollow microtubes into the matrix of PLGA-PEG-PLGA resulted in the hydrogel with much rougher surface, enhanced mechanical strength, and bright upconversion luminescence. The in vitro experiments showed that the composite hydrogel possessed ideal sustained drug release property for protein drugs. Besides, it also exhibited good cellular compatibility and cell adhesion property for bone marrow mesenchymal stem cells. After loading of recombinant human bone morphogenetic protein 2 (osteogenic induction factor), the composite hydrogel was definitively implanted into the tibial defect of rats to evaluate the bone regeneration. The degradation of the composite hydrogel scaffolds and the bone defect repairing in vivo was noninvasive monitored by real-time upconversion luminescent imaging and X-ray computed tomography. The results showed that the composite hydrogel scaffold was completely degraded after 4 weeks. Moreover, a successful tibial defect repairing was realized after 6 weeks of bone regeneration. The hematoxylin-eosin staining experiments showed that the implantation and degradation of the composite hydrogel have no significant damages to the organs of heart, liver, spleen, lung and kidney during the therapeutic process, indicating its good biological safety. Our strategy provides a safety way for the noninvasive monitoring of bone regeneration, which is believed to have great potential clinical uses.

Engineering Wake Induction Model For Axisymmetric Multi-Kite Systems

Multi-kite airborne wind energy systems (MAWES) fly two or more kites in a high-altitude orbit that allows a main tether to unroll a generator. An engineering wake induction model could simplify the (axisymmetric) aerodynamics of such an unsteady actuator-annulus with variable thrust-coefficient, flight-radius, and downwind-direction apparent velocity, in comparison to high-fidelity wake models. To the authors’ knowledge, existing engineering models do not predict the influence of variable flight radius. The goal of this paper is to synthesize a MAWES engineering model, a closed-form function approximating the axial induction factor ã, specifically at the kite mid-span, using linearized wake parameters, as available from a dynamics solver. A vortex tube model is used to construct a plausible approximation of the induction, which is then heavily simplified for computation tractability while retaining important flow physics.

Effects of Notch signal on the expressions of HIF-α and autophagy- related genes Beclin1, LC3I, LC3II in oxygen-glucose deprivation induced myocardial cell injury

To investigate the effects of Notch signal on hypoxic induction factor (HIF-1α) and autophagy-associated genes Beclin1, LC3I, LC3II in oxygen-glucose deprivation (OGD) induced myocardial cell injury. The OGD model was established using hypoxic culture box and hypoglycemic DMEM medium. The cells were divided into normal control group, OGD group, OGD + NC siRNA group, OGD + Notch1 siRNA group and OGD + HIF-1α siRNA group. Western blot was used to detect the interference effects of HIF-1α siRNA and Notch1 siRNA. The effects of Notch1 siRNA and HIF-1α siRNA on the activity of myocardial cells in OGD model were detected by the CCK-8 assay. The effects of Notch1 siRNA and HIF-1α siRNA on autophage-associated genes Beclin1, LC3I and LC3II expression were detected by Western blot. The results of Western blot showed that HIF-1α siRNA could effectively knock down the expression of HIF-1α in myocardial cells in OGD model, and Notch1 siRNA could effectively knock down the expression of Notch1 and HIF-1α in myocardial cells in OGD model. The result of CCK-8 assay showed that Notch1 siRNA and HIF-1α siRNA reduced the activity of myocardial cells in OGD model, and there was no statistical difference between the two groups. Western blot results showed that Notch1 siRNA and HIF-1α siRNA could reduce the expressions of the autophagy-associated genes Beclin1, LC3I and LC3II, and reduce the ratio of LC3II to LC3I at mRNA level. Notch1 plays a role in myocardial protection by regulating the expression of HIF-1α to regulate the autophagy in OGD model cells.