Assessment of a Bio-inspired Artificial Wing for Micro Aerial Vehicle Based on Structural Bio-mimetics

This paper presents the structural design assessment of a bio-inspired artificial wing for flapping wing micro air vehicle based on pigeon bird. Bio-inspired ornithopters are unable to implement themselves in surveillance environment due to lack of basic bio-mimetics during conceptual and design phase. The idea of this research is to bridge this gap through assessment of structural parameters including weight, moment of inertia and feather placement leading to development of an artificial wing using actual feathers of pigeon bird and glass fiber-epoxy composite. The camber and wing structure is assessed through the fabrication of mold which is further utilized to define the shape of artificial wing. Future work includes the performance assessment of the developed wing for lift and thrust generation in an actual prototype of flapping type micro air vehicle

Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN): an international, randomised, double-blind, placebo-controlled trial

Background Post-partum haemorrhage is the leading cause of maternal death worldwide. Early administration of tranexamic acid reduces deaths due to bleeding in trauma patients. We aimed to assess the effects of early administration of tranexamic acid on death, hysterectomy, and other relevant outcomes in women with post-partum haemorrhage. Methods In this randomised, double-blind, placebo-controlled trial, we recruited women aged 16 years and older with a clinical diagnosis of post-partum haemorrhage after a vaginal birth or caesarean section from 193 hospitals in 21 countries. We randomly assigned women to receive either 1 g intravenous tranexamic acid or matching placebo in addition to usual care. If bleeding continued after 30 min, or stopped and restarted within 24 h of the first dose, a second dose of 1 g of tranexamic acid or placebo could be given. Patients were assigned by selection of a numbered treatment pack from a box containing eight numbered packs that were identical apart from the pack number. Participants, care givers, and those assessing outcomes were masked to allocation. We originally planned to enrol 15 000 women with a composite primary endpoint of death from all-causes or hysterectomy within 42 days of giving birth. However, during the trial it became apparent that the decision to conduct a hysterectomy was often made at the same time as randomisation. Although tranexamic acid could influence the risk of death in these cases, it could not affect the risk of hysterectomy. We therefore increased the sample size from 15 000 to 20 000 women in order to estimate the effect of tranexamic acid on the risk of death from post-partum haemorrhage. All analyses were done on an intention-to-treat basis. This trial is registered with ISRCTN76912190 (Dec 8, 2008); ClinicalTrials.gov, number NCT00872469; and PACTR201007000192283. Findings Between March, 2010, and April, 2016, 20 060 women were enrolled and randomly assigned to receive tranexamic acid (n=10 051) or placebo (n=10 009), of whom 10 036 and 9985, respectively, were included in the analysis. Death due to bleeding was significantly reduced in women given tranexamic acid (155 [1·5%] of 10 036 patients vs 191 [1·9%] of 9985 in the placebo group, risk ratio [RR] 0·81, 95% CI 0·65–1·00; p=0·045), especially in women given treatment within 3 h of giving birth (89 [1·2%] in the tranexamic acid group vs 127 [1·7%] in the placebo group, RR 0·69, 95% CI 0·52–0·91; p=0·008). All other causes of death did not differ significantly by group. Hysterectomy was not reduced with tranexamic acid (358 [3·6%] patients in the tranexamic acid group vs 351 [3·5%] in the placebo group, RR 1·02, 95% CI 0·88–1·07; p=0·84). The composite primary endpoint of death from all causes or hysterectomy was not reduced with tranexamic acid (534 [5·3%] deaths or hysterectomies in the tranexamic acid group vs 546 [5·5%] in the placebo group, RR 0·97, 95% CI 0·87-1·09; p=0·65). Adverse events (including thromboembolic events) did not differ significantly in the tranexamic acid versus placebo group. Interpretation Tranexamic acid reduces death due to bleeding in women with post-partum haemorrhage with no adverse effects. When used as a treatment for postpartum haemorrhage, tranexamic acid should be given as soon as possible after bleeding onset. Funding London School of Hygiene & Tropical Medicine, Pfizer, UK Department of Health, Wellcome Trust, and Bill & Melinda Gates Foundation

Structural Design Analysis of a 500 kW Wind Turbine

This report presents briefly the structural design analysis of a 500kW two-bladed downwind type wind turbine indigenous developed under NMITLI program. The major components developed were rotor blades, teetered hub, rotor shaft, platform and yaw system whereas gear box and alternator were procured. Several configurations were initially explored for each subsystem and finally the suitable one for a prototype was fabricated. The wind turbine developed composed of minimum elementary systems required for prototype testing. The design has been rationalized/ simplified for single set/piece fabrication. The aerodynamic design of the blade was carried out in a separate exercise and the aerodynamic loads obtained were used for this structural analysis. Further, a special purpose code, “BLADED’ was used to generate aerodynamic loads for some cases. The critical loads in all phases of wind turbine existence were identified and used in the design. The blade apart from generating power is the source from where all the dynamic loads originates. The blade shell was made out of glass-epoxy laminates. The load carrying spar integrated with the shell of the blade composed of more UD layers. Foam sandwich construction was employed in non-critical area. The blade was attached to the hub flange with use of T-Bolts embedded into the root. Preload was introduced into the T-Bolt to improve it’s the fatigue life. Shaft and teeter pin were made out of forged EN24 steel whereas hub, platform and yaw system were fabricated out of plates by welding. Thus, the design exercise was focused for the prototype wind turbine development

Technology Driven Programme for the Development for the Development of a Fixed wing micro Air Vehicle at NALDRIVEN

At NAL, we are developing Black Kite - a 300mm span fixed wing autonomous Micro Air Vehicle (MAV) with an endurance of 30 minutes. The first version of this indigenous MAV has been successfully flight-tested in two modes: radio-controlled, and recently, semi-autonomous. The autopilot system used in Black Kite has been developed indigenously and is state-of-the-art. During the development of such an autonomous vehicle, we accommodated for the rapidly improving technology and constantly updated our design to account for this. Especially, the disciplines of material and structural technology, navigation and control using miniature autopilot grew leaps and bounds during the design process time period. Interestingly, some of the technologies became obsolete during this time, and corrective action became necessary. Although the latest trend in technologies enabled improved engineering, the scientific input for the development remained well defined and mostly unaltered. The goal of this paper is to explain the impact of emerging technologies on the development of our modern MAV, Black Kite , at NA

Advanced Research Areas for the Development of Autonomous Micro Air vehicles : An overview

For the past one decade great impetus is given to the development of Micro Air Vehicles (MAV). It is an autonomous flying vehicle capable of carrying a payload. The maximum linear dimension of this machine is 150 to 300mm and its weight can vary from 100 to 300 grams. The flight speed is around 10m/s and it operates at Reynolds number in the range of 5x104 to 2x105. MAV flies in the low Re regime and hence there is a marked deterioration of Lift at most operating conditions. This calls for the use of some lift enhancing techniques. Another important criteria is the control aspect of this type tiny vehicles. All these demands can be met only by choosing an appropriate structure/power plant. Flight testing and fabrication of these machines also pose many difficulties and it is tough challenge to design and fly a MAV in the autonomous mode . MAVs can carry various special sensors as payload to support such civil and military missions as traffic monitoring, weather observation, anti terrorists operations and enemy surveillance

Design of a High Altitude Fixed Wing Mini UAV – Aerodynamic Challenges

This paper attempts to bring out the challenges associated with the design of a high altitude mini UAV especially from the aerodynamics perspective. The mini UAV under consideration is a 2 kg class conventional, high wing and T-Tail configuration. A comparative study of various high lift airfoils has been done to illustrate that the selection of a suitable airfoil for high altitude applications is indeed an important part of the design activity and it shows that the wing loading of a UAV designed for high altitudes does not depend on the changes in air density alone. The chosen high lift low Reynolds number airfoil is found to have a minor effect on the aerodynamic parameters (Cl and Cd) with changes in Reynolds number. This paper also addresses the performance variation due to operation at off design condition such as at sea level

The Effect of Introducing Redundancy in a Probabilistic Forwarding Protocol

This paper is concerned with the problem of broadcasting information from a source node to every node in an ad-hoc network. Flooding, as a broadcast mechanism, involves each node forwarding any packet it receives to all its neighbours. This results in excessive transmissions and thus a high energy expenditure overall. Probabilistic forwarding or gossiping involves each node forwarding a received packet to all its neighbours only with a certain probability p. In this paper, we study the effect of introducing redundancy, in the form of coded packets, into a probabilistic forwarding protocol. Specifically, we assume that the source node has k data packets to broadcast, which are encoded into n >= k coded packets, such that any k of these coded packets are sufficient to recover the original k data packets. Our interest is in determining the minimum forwarding probability p for a ``successful broadcast'', which we take to be the event that the expected fraction of network nodes that receive at least k of the n coded packets is close to 1. We examine, via simulations and analysis of a number of different network topologies (e.g., trees, grids, random geometric graphs), how this minimum forwarding probability, and correspondingly, the expected total number of packet transmissions varies with the amount of redundancy added. Our simulation results indicate that over network topologies that are highly connected, the introduction of redundancy into the probabilistic forwarding protocol is useful, as it can significantly reduce the expected total number of transmissions needed for a successful broadcast. On the other hand, for trees, our analysis shows that the expected total number of transmissions needed increases with redundancy

A study on short term treatment response of connective tissue disease related interstitial lung disease

Background: Interstitial lung disease is a major cause of morbidity and mortality in patients suffering from connective tissue diseases. Early detection and prompt recognition of symptoms with appropriate treatment is necessary for effective control of the disease and for better prognosis and long-term survival. Aim: To study the short-term treatment response of patients with connective tissue disease-related interstitial lung disease. Objectives: The purpose of this study was to evaluate the treatment response of connective tissue disease-related interstitial lung disease patients treated with intravenous pulses of cyclophosphamide (CYP) based on improvements in lung function: forced vital capacity (FVC)% predicted, forced expiratory volume in the first second (FEV1)% predicted, dyspnea Borg scale and 6-minute walk test. To determine the factors affecting the treatment outcomes like age, sex, duration of the connective tissue disease, type of connective tissue disease, HRCT type, and presence of PAH. Methods: A cohort study was conducted in the Department of General Medicine, Rheumatology, and Pulmonology at the Amala Institute of Medical Sciences, Thrissur, and Kerala from November 2015 to June 2017 that evaluated 74 patients having connective tissue disease-related ILD. A detailed history and a thorough clinical examination were done.&nbsp