Non-Gaussian Wind Pressure Characteristics of HAWT Tower System with and Without Rotor

Generally, the Gaussian assumption has been considered in analyzing the data pertaining to the wind effects on the structures or bluff bodies due to the abundance of the statistical information. In this study, Horizontal Axis Wind Turbine (HAWT) tower system with dimension of 1:330 scale is studied in order to understand their peak pressure behavior for wind resistant design. Generally, tower systems are constructed of various geometrical structures such as lattice towers, tubular steel towers, concrete towers, but in this present study tubular cylindrical tower is only considered. Simultaneous pressure measurements on the surface of the tower were performed in the low-speed boundary layer wind tunnel with test section dimension of 18 m × 2.5 m × 2.15 m having Reynolds number ranging from 102 to 104. The peak pressures acting on the tower systems are calculated for a number of ten-minute samples on various locations of the wind turbine. Peak value calculations based on Gaussian and Non – Gaussian processes are discussed mathematically and applied to the data collected from the wind tunnel tests. A mathematical model of Davenport and Kareem – Zhou is used in calculating the peak factor for Gaussian and non – Gaussian processes, respectively. The results indicate that higher moments dominate as most of the distribution is skewed and with kurtosis value. Henceforth, a study on extreme value analysis is deemed necessary in designing wind resistant structures or bluff bodies. Considering Gaussian nature alone may under-represent the peak value of the HAWT tower

Consistency of the kernel density estimator - a survey

Various consistency proofs for the kernel density estimator have been developed over the last few decades. Important milestones are the pointwise consistency and almost sure uniform convergence with a fixed bandwidth on the one hand and the rate of convergence with a fixed or even a variable bandwidth on the other hand. While considering global properties of the empirical distribution functions is sufficient for strong consistency, proofs of exact convergence rates use deeper information about the underlying empirical processes. A unifying character, however, is that earlier and more recent proofs use bounds on the probability that a sum of random variables deviates from its mean

EFFECT OF PITCH ANGLE ON BLADE -TOWER INTERFERENCE ON HAWT

ABSTRACT In the wind turbine, the distribution of wind is altered by the presence of the tower. For upwind rotors, the flow of wind in front of the tower is redirected thereby reduces the torque at each blade. The performance of the wind turbine is affected by such influence of interference. Hence, it is important to understand the flow interference between blade and tower. In this research, the wind turbine blade with various pitch angles has been studied both computationally and experimentally. The result shows that the influence of interference leads to negative pressure region on the tower where the blade interference occurs. Hence this leads a slowdown of rotor locally for every 120 degree, this in turn affect the power performance and decrease the structural stability

Real-world experience of intravenous ferric derisomaltose evaluated through safety and efficacy reporting in the UK

Ferric derisomaltose (FDI; Monofer) is used in clinical practice to treat iron deficiency, but the safety and efficacy of FDI has not been robustly evaluated in a large real-world study. This retrospective, multicentre, audit-based, observational study provides pragmatic information about safety and clinical responses with FDI across therapy areas and patient populations, helping to facilitate treatment decisions. Participating sites provided data from the medical records of adults who had received ≥ 1 FDI infusion. The primary outcome was the incidence of adverse reactions within 24 hours of the FDI infusion. Secondary outcomes included the change from baseline in haemoglobin and ferritin up to 12 months post infusion. In total, 19 sites provided data for a total of 7354 FDI-treated patients; 64.3% of patients were female, and 42.2% were aged ≥ 70 years. Surgery was the main hospital specialty (34.5%). The incidence of any recorded adverse reactions, hypersensitivity reactions, and anaphylaxis were 1.7%, 0.4%, and < 0.1%, respectively, regardless of baseline anaemia status. Statistically significant increases in haemoglobin and ferritin were observed between baseline and Month 4 following FDI treatment (p < 0.0001). Improvements in haemoglobin were more pronounced for hospital specialties where operative blood loss is expected (surgery/obstetrics) compared with those where blood loss is not expected. This study provides real-world clinical evidence for the low risk of adverse reactions with FDI across diverse patient populations, providing reassurance that intravenous iron is not associated with serious toxicity. These findings may inform changes in intravenous iron delivery to provide effective therapy to more patients in need.This article is freely available online. Click on the 'Additional Link' above to access the full-text via the publisher's site.Published version, accepted version, submitted versio

Aerodynamic Characteristics of Shark Scale-Based Vortex Generators upon Symmetrical Airfoil

A series of wind tunnel tests were carried out to determine the effect of shark scale-based vortex generators (SSVG) on a NACA 0015 symmetrical airfoil’s aerodynamic characteristics. Three different sets of SSVG with varying geometrical parameters, such as chord length, amplitude, and wavelength, were designed and fabricated using 3D printing. The SSVG models were blended to the baseline NACA 0015 symmetrical airfoil. The wind tunnel experiments were performed over the test airfoil mounted with different sets of SSVG at various angles of attack, ranging from 0° to 24° in increments of 3°, and operating in the range of Re = 2 × 105. The results revealed that the SSVG blended test airfoil reduced the drag and increased the maximum coefficient of lift (CLmax), thereby enhancing the overall aerodynamic performance. The SSVG offered noteworthy aerodynamic benefits by effectively altering the flow and causing significant spanwise variation in the flow properties. Additionally, attempts were made to identify the optimum chordwise location to blend the SSVG for effective use

Morpho-syntactic concept and contribution of Tholkaappiyar : a view from a different prism

The concept of morpho-syntax is defined as ‘the study of grammatical affixes or linguistic units that have both morphological and syntactic properties’. The author of Tholkaappiyam, the earliest written Tamil grammar of 300 B.C., explains this concept exhaustively in different chapters. This notion of modern Linguistics is to be added as one of the levels of language for research and teaching grammar as well. A per the author of the grammar, tense is a morpho-semantic feature, which is added to finite verbs. Tense marker attributes to the meaning of the sentence and not to the sentence structure. That was his concept and contribution to the field of Linguistics. Features like, metonymy, ambiguity, gerund formation, etc., in the grammar, support the concept proposed. Selected verses from Tholkaappiyam have been quoted for the sustenance of his view. Additionally, this article brings in another very important concept of ‘mid-fix’, which is a new contribution to the field

Integrity and regeneration of mechanotransduction machinery regulate aminoglycoside entry and sensory cell death

Sound perception requires functional hair cell mechanotransduction (MET) machinery, including the MET channels and tip-link proteins. Prior work showed that uptake of ototoxic aminoglycosides (AG) into hair cells requires functional MET channels. In this study, we examined whether tip-link proteins, including Cadherin 23 (Cdh23), regulate AG entry into hair cells. Using time-lapse microscopy on cochlear explants, we found rapid uptake of gentamicin-conjugated Texas Red (GTTR) into hair cells from three-day-old Cdh23(+/+) and Cdh23(v2J/+) mice, but failed to detect GTTR uptake in Cdh23(v2J/v2J) hair cells. Pre-treatment of wildtype cochleae with the calcium chelator 1,2-bis(o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA) to disrupt tip-links also effectively reduced GTTR uptake into hair cells. Both Cdh23(v2J/v2J) and BAPTA-treated hair cells were protected from degeneration caused by gentamicin. Six hours after BAPTA treatment, GTTR uptake remained reduced in comparison to controls; by 24 hours, drug uptake was comparable between untreated and BAPTA-treated hair cells, which again became susceptible to cell death induced by gentamicin. Together, these results provide genetic and pharmacologic evidence that tip-links are required for AG uptake and toxicity in hair cells. Because tip-links can spontaneously regenerate, their temporary breakage offers a limited time window when hair cells are protected from AG toxicity