Effect of wingtip morphing on the roll mode of a flexible aircraft

It is well known that increasing wing span leads to improved aerodynamic performances. To comply with airport infrastructure limits, ground folding wingtips are implemented as a solution for wing span extension. To further justify the mechanism's weight penalty the concept of in- ight folding is investigated here. A time domain aeroservoelastic simulation framework is used to asses its impact on lateral ight dynamics. An established system identi cation method, was used to derive key lateral aerodynamic derivatives and investigate the aircraft's roll handling qualities. A range of wingtip de ections and various ight conditions were used to generate a su ciently large database of coe cients to assess the e ect of wingtip morphing as a function of airframe exibility and ight conditions. Results show that overall, small changes in lateral aerodynamic derivatives are introduced with wingtip morphing. Di erent trends in aerodynamic derivatives were identi ed as a function of ight condition and wingtip de ection, leading to the derivation of prediction models to replace the aerodynamic derivatives database

Method to assess lateral handling qualities of aircraft with wingtip morphing

The impact of in- ight folding wingtip on roll characteristics of aircraft has been studied in the past. In this study, a handling qualities assessment carried out to de-risk further development of such a device. A specialised ight simulation campaign is prepared to evaluate the roll dynamics in di erent morphing con gurations. Various manoeuvres, including the O set Landing Manoeuvre and herein presented Slalom and Alignment Tracking task are used. Cooper Harper Rating scales and ight data analysis are used to collect pilot opinion and validate pilot-in-the-loop simulation results. This example is used to demonstrate the use of the slalom and Alignment Tracking manoeuvre for lateral dynamic assessment

Flexible high aspect ratio wing: Low cost experimental model and computational framework

Aircraft concepts of tomorrow, such as high aspect ratio wing aircraft, are far more integrated between technical disciplines and thus require multidisciplinary design approaches. Design tools able to predict associated dynamics need to be developed if such wing concepts are to be matured for use on future transport aircraft. The Cranfield University Beam Reduction and Dynamic Scaling ( BeaRDS) Programme provides a framework that scales a conceptual full size aircraft to a cantilevered wing model of wind tunnel dimensions, such that there is similitude between the static and dynamic behaviour of the model and the full size aircraft. This process of aeroelastically scaled testing combines the technical disciplines of aerodynamics, flight mechanics and structural dynamics, to provide a means by which future concept aircraft can be de-risked and explored . Data acquisition from wind tunnel testing can then be used to validate fluid-structure interaction frameworks that model the aeroelastic effect on the flight dynamics of the aircraft. This paper provides an overview of the BeaRDS methodology, and focuses on the Phase I of the programme, being the development of a reduced Cranfield A-13 aircraft cantilevered wing, to mitigate risk associated with the manufacturing and instrumentation app roach. It is shown that a low cost acquisition system of commercial Inertial Measurement Units (IMUs) can measure the response of the wing within the desired frequency range. Issues associated with the Phase I testing are discussed, and methods are proposed for the Phase II programme that allow these problems to be resolved for a larger scale flexible wing with active control surfaces

Effect of grafting time on graft success of walnut (Juglans regia) in zero energy polyhouses

This study was carried out during three successive seasons (2009, 2010 and 2011) on walnut (Juglans regia L.) seedlings. Grafting was done by wedge methods on nine dates (5 January, 15 January, 25 January, 5 February, 15 February, 25 February, 5 March, 15 March and 25 March). The pooled data showed that, highest success percentage of grafting was obtained on 25 January and lowest was recorded on 25 March. The maximum number of shoots/scion and leaves/scion was observed on 25 January. The highest value for scion diameter (0.94cm) was found on seedlings grafted on 25 January while as lowest scion diameter of 0.45cm from grafts, grafted on 25 March. The highest proportion of salable plants was observed on 15 January and lowest proportion was found on 25 March. Our results also suggest that January grafting produces better bud-take, number of leaves and scion growth as compared with February and March grafting. Therefore, the best time for grafting is January under polyhouse conditions

Circadian Consequence of Socio-Sexual Interactions in Fruit Flies Drosophila melanogaster

In fruit flies Drosophila melanogaster, courtship is an elaborate ritual comprising chasing, dancing and singing by males to lure females for mating. Courtship interactions peak in the night and heterosexual couples display enhanced nighttime activity. What we do not know is if such socio-sexual interactions (SSI) leave long-lasting after-effects on circadian clock(s). Here we report the results of our study aimed at examining the after-effects of SSI (as a result of co-habitation of males and females in groups) between males and females on their circadian locomotor activity rhythm. Males undergo reduction in the evening activity peak and lengthening of circadian period, while females show a decrease in overall activity. Such after-effects, at least in males, require functional circadian clocks during SSI as loss-of-function clock mutants and wild type flies interacting under continuous light (LL), do not display them. Interestingly, males with electrically silenced Pigment Dispersing Factor (PDF)-positive ventral lateral (LNv) clock neurons continue to show SSI mediated reduction in evening activity peak, suggesting that the LNv clock neurons are dispensable for SSI mediated after-effects on locomotor activity rhythm. Such after-effects in females may not be clock-dependent because clock manipulated females with prior exposure to males show decrease in overall activity, more or less similar to rhythmic wild type females. The expression of SSI mediated after-effects requires a functional olfactory system in males because males with compromised olfactory ability do not display them. These results suggest that SSI causes male-specific, long-lasting changes in the circadian clocks of Drosophila, which requires the presence of functional clocks and intact olfactory ability in males

The Molecular Clockwork of the Fire Ant Solenopsis invicta

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication

Cerebral embolization associated with parenchymal seeding of the left atrial myxoma : Potential role of interleukin-6 and matrix metalloproteinases

Systemic embolization has been reported in up to 40% of patients with left atrial myxoma, half of them with cerebral involvement. However, development of intracerebral embolization associated with parenchymal seeding of the myxoma emboli is an extremely rare complication, with only 36 histologically diagnosed cases reported in the published literature. We describe a 69-year-old woman who arrived at the emergency service with hemiparesis associated with drug-resistant epilepsy and a medical history of resection of a left atrial myxoma 10 months previously. Cranial computed tomography revealed multiple large lesions of heterogeneous density and cystic components in the occipital lobes and posterior fossa parenchyma. Histopathological analyses after stereotactic biopsy of the occipital lesion revealed infiltrative myxoma cells with benign histological findings and uniform expression of calretinin similar to that of the primary cardiac myxoma. Additional immunohistochemical studies confirmed brain parenchymal seeding of the myxoma cells with strong expression of interleukin-6 (IL-6) and focal expression of matrix metalloproteinases-2 (MMP-2). Here, we discuss the clinicopathological features of intracerebral embolization of left atrial myxomas associated with progressive parenchymal seeding of the tumor emboli and the potential pathogenic role of IL-6 and MMPs.Peer reviewe

Structure and mechanism of human DNA polymerase η

The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase eta (Pol eta), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol eta at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol eta acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol eta orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol eta missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol eta in replicating through D loop and DNA fragile sites