Optimal design of an aeroelastic wing structure with seamless control surfaces

This article presents an investigation into the concept and optimal design of a lightweight seamless aeroelastic wing (SAW) structure for small air vehicles. Attention has been first focused on the design of a hingeless flexible trailing edge (TE) control surface. Two innovative design features have been created in the SAW TE section: an open sliding TE and a curved beam and disc actuation mechanism. This type of actuated TE section allows for the SAW having a camber change in a desirable shape and minimum control power demand. This design concept has been simulated numerically and demonstrated by a test model. For a small air vehicle of large sweep back wing, it is noted that significant structural weight saving can be achieved. However, further weight saving is mainly restricted by the aeroelastic stability and minimum number of carbon/epoxy plies in a symmetric layup rather than the structural strength. Therefore, subsequent effort was made to optimize the primary wing box structure. The results show that an initial structural weight can be reduced significantly under the strength criterion. The resulting reduction of the wing box stiffness and aeroelastic stability and control effectiveness can be improved by applying the aeroelastic tailoring. Because of the large swept angle and resulting lightweight and highly flexible SAW, geometrical non-linearity and large bending-torsion aeroelastic coupling have been considered in the analysis

Optimal Packetization Interval for VoIP Applications Over IEEE 802.16 Networks

An analysis of the impact of the packetization interval for constant bit rate traffic has been done in the context of IEEE 802.16 MAC layer. Bandwidth used for overheads which include lower layer headers as well as retransmissions at the MAC layer are considered. An optimal packetization interval selection method for delay sensitive applications such as VoIP is proposed. Enhancements to the Unsolicited Grant Service retransmission strategy are proposed to further improve delay and minimize packet loss while making efficient use of the limited bandwidth resource

Availability legibility and adequacy of diagnosis as entered in bed head ticket in a base hospital Sri Lanka: a descriptive cross-sectional study

Introduction: Hospital information storage is done through an internationally accepted coding system. It is very important to have an accurate diagnosis for proper coding. Ministry of Health has issued a circular (No-01-05/99) for the documentation of Bed Head Ticket (BHT) including writing the correct diagnosis.  Objective: To assess the availability, legibility, and adequacy of diagnosis as entered in the BHTs of selected wards in a base hospital in Sri Lanka. Methods: Descriptive cross-sectional study was conducted to assess availability, legibility, and adequacy of diagnosis as entered in 384 BHTs of selected wards in a Base Hospital in Sri Lanka. A data Extraction sheet (DES) was used as a study instrument.  Results: Out of 384 BHTs diagnosis were not available in 12 (3.13%) BHTs and diagnosis were illegible in 36(6.99%) BHTs. In 244(67.59%) BHTs diagnosis were written as abbreviations. Only in136(37.46%) BHTs, diagnosis were written in block capital letters. Conclusion and recommendation: Documentation diagnosis in the BHTs is not according to the standards. Therefore, medical administrators, policymakers, and clinicians should take urgent actions to improve documentation diagnosis in BHTs

Dietary Composition and Foraging Habitat Selection of the Indian Pangolin (Manis crassicaudata) in a Tropical Lowland Forest-Associated Landscape in Southwest, of Sri Lanka

Indian pangolins (Manis crassicaudata) is a nocturnal elusive mammal species with a wide distribution in the South Asian region. The species has become threatened all over its range countries due to hunting, poaching, trafficking and habitat destruction. Many of the captive breeding and rescue attempts has been unsuccessful due to the lack of scientific knowledge on the dietary ecology of the species. Hence, this study investigated the dietary spectrumand foraging habitat selection of the Indian pangolin in a tropical lowland forest-associated landscapes of Southwest Sri Lanka. We studied fived different types of foraging habitats of Indian pangolin i.e. forested habitat, rubber plantations, cinnamon cultivations, oil palm plantations, and tea-dominated home gardens.The foraging intensity were assessed using the signs of foraging activities ad faecal samples of pangolins gathered in five 10×10 m plots along ten transect in each habitat. Faecal samples were further subjected to microscopic analysis in the laboratory. Study results identified forested habitats as the most preferred foraging grounds of Indian pangolins followed by the rubber plantations, cinnamon, oil palm and tea dominated home gardens. The termites from the termitariaon ground and the termite infested logs are identified as most frequently foraged food item in the studied habitats. Laboratory analysis of faecal matter further revealed that the undigested matter (by weight) predominantly constituted of grit (53.3%), animal matter (37%) and plant matter (9.7%). The digestibility of termites appears to be high compared to ants and other insects. Higher abundance of the heads, mouthparts, abdomens, and legs of ants compared to those appendages of termites in the analysed faecal samples suggest a higher digestibility of above mentioned body parts of termites than the ants. The wings of the termites also found in greater abundance in the analysed faecal samples. Termites belong to the genus Odontotermes and the ant species belong to the genera Oecophylla, Anoplolepis, Camponotus and Monomorium were identified as the main prey species of the Indian pangolin in the studied habitats. The findings of the study also suggest that human modified agricultural lands adjoining forest are important as feeding grounds of Indian pangolins, and worth considering in long-term conservation planning of the species. Keywords: Indian pangolin, Dietary spectrum, Foraging habitat, Faecal analysi

Theory of transient spectroscopy of multiple quantum well structures

A theory of the transient spectroscopy of quantum well (QW) structures under a large applied bias is presented. An analytical model of the initial part of the transient current is proposed. The time constant of the transient current depends not only on the emission rate from the QWs, as is usually assumed, but also on the subsequent carrier transport across QWs. Numerical simulation was used to confirm the validity of the proposed model, and to study the transient current on a larger time scale. It is shown that the transient current is influenced by the nonuniform distribution of the electric field and related effects, which results in a step-like behavior of the current. A procedure of extraction of the QW emission time from the transient spectroscopy experiments is suggested.Comment: 5 pages, 4 figures, to be published in J. Appl. Phy

Tapered whisker reservoir computing for real-time terrain identification-based navigation

This paper proposes a new method for real-time terrain recognition-based navigation for mobile robots. Mobile robots performing tasks in unstructured environments need to adapt their trajectories in real-time to achieve safe and efficient navigation in complex terrains. However, current methods largely depend on visual and IMU (inertial measurement units) that demand high computational resources for real-time applications. In this paper, a real-time terrain identification-based navigation method is proposed using an on-board tapered whisker-based reservoir computing system. The nonlinear dynamic response of the tapered whisker was investigated in various analytical and Finite Element Analysis frameworks to demonstrate its reservoir computing capabilities. Numerical simulations and experiments were cross-checked with each other to verify that whisker sensors can separate different frequency signals directly in the time domain and demonstrate the computational superiority of the proposed system, and that different whisker axis locations and motion velocities provide variable dynamical response information. Terrain surface-following experiments demonstrated that our system could accurately identify changes in the terrain in real-time and adjust its trajectory to stay on specific terrain

Markov and Neural Network Models for Prediction of Structural Deterioration of Stormwater Pipe Assets

Storm-water pipe networks in Australia are designed to convey water from rainfall and surface runoff. They do not transport sewerage. Their structural deterioration is progressive with aging and will eventually cause pipe collapse with consequences of service interruption. Predicting structural condition of pipes provides vital information for asset management to prevent unexpected failures and to extend service life. This study focused on predicting the structural condition of storm-water pipes with two objectives. The first objective is the prediction of structural condition changes of the whole network of storm-water pipes by a Markov model at different times during their service life. This information can be used for planning annual budget and estimating the useful life of pipe assets. The second objective is the prediction of structural condition of any particular pipe by a neural network model. This knowledge is valuable in identifying pipes that are in poor condition for repair actions. A case study with closed circuit television inspection snapshot data was used to demonstrate the applicability of these two models

Comparison of T2-weighted Magnetic Resonance Imaging findings with histological findings in degenerated lumbar discs in patients with lumbar disc herniation

Diagnosis of disc degeneration and herniation largely depends on Magnetic Resonance Imaging (MRI) and X-rays which fails to detect early disc degeneration. This study was conducted to compare the degenerative changes seen in histological assessment with T2-weighted MRI findings. The study recruited 104 patients with lumbar disc herniation undergoing lumbar discectomy. Excised lumbar disc fragments were taken for histology and T2-weighted MRI was conducted prior to the surgery. Excised disc fragments were subjected to routine histology procedure and van Gieson stain for collagen was performed on each specimen.  Disc degeneration was assessed by histological parameters and T2-weighted MRI findings. The majority of subjects (94.2%) showed degenerative changes of the excised portion of the lumbar discs in histological assessment of the disc. However, T2-weighted MRI findings of degenerative changes of the discs were comparatively less (35.6%). According to the histological assessment, higher percentage (61.5 %) of discs were moderately degenerated while 7.7 % had severely degenerated discs. All patients who were confirmed for disc degeneration with T2-weighted MRI (n=37) had confirmed degenerative changes in the histological assessment as well. Histological degenerative alterations were observed in the majority of patients when compared to detectable degenerative changes in T2-weighted MRI suggesting the importance of histological assessment of degeneration in the excised intervertebral disc fragments. As early degenerative changes are not detected by the standard T2weighted MRI technique, if neglected, can progress to severe stages resulting in more discomfort and pain to the patients. KEYWORDS:    Disc degeneration, Histology, Magnetic Resonance Imaging &nbsp