296 research outputs found

    Road traffic accidents in Libya: An undeclared War

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    To The Editor: In his outstanding article regarding Road Traffic Accidents (RTAs) in Libya [1], Dr Abdulmajid Ali has raised awareness and started a debate about this extremely important issue. Before responding to some points in Dr Ali’s article, I would like to tell a real story of a tragic accident that happened last week, which highlights several issues related to RTAs in Libya. A 55 year old driver left after Fajr prayer to the vegetable market to buy a few things for his daughter’s wedding lunch. While trying to avoid a big pothole in the middle of the road, he was hit by a truck without headlights coming from the opposite direction. The truck driver continued driving as if nothing had happened. None of the road users cared to help the victim but he was able to contact his son by mobile phone to come and help him out of the wreckage. His son took him to the main Trauma Hospital in Tripoli. The patient had no external injuries. He was admitted for observation only. A few hours later the patient died as a result of major internal haemorrhage. Further information revealed that the truck driver had no driving licence and the truck was not road worthy.This story is not unique However, it highlights the complex and intermingled issues that need to be addressed to have any real impact on this disastrous problem in Libya. The specific points I would like to add to Dr Ali’s article are:There is no doubt that RTAs are a major killer in Libya especially in the young age group. The annual reporting of road causalities is considered to be the yard stick to measure the effectiveness of any national traffic policy,; in the UK for example the target is to reduce fatalities from RTAs by 50% by 2010 [2]. It is a disgrace not to have accurate official statistics published at least annually of fatalities, injuries, disabilities and the economic consequences of this undeclared war in Libya. There is evidence to support that there could be a positive impact when national health challenges are tackled systematically [3-5]. It is perplexing not to have a Libyan National Traffic Policy to deal with this very serious issue comprehensively.The majority of serious accidents in Libya occur on motorways. Internationally, motorways are organised in such a way that traffic can only leave or join the motorway through specified junctions. In contrast, in Libyan motorways, other vehicles can join the motorway unpredictably at any point, left or right and sometimes from above or below! Personally I think that the lack of a Highway Code or its implementation is a major contributing cause for serious RTAs.The Libyan Traffic Police Force needs a shakeup to root out the few corrupt officers who brought what used to be a highly regarded force into disrepute because of their indiscipline. The force needs support, respect and incentives, one of which is to link their pay rise to the national reduction of RTAs.To be slightly provocative, I would like to call for a public inquiry into the issue of RTAs in Libya. This is a very robust way to learn lessons and implement corrective changes (please see www.hse.gov.uk Railway Public inquiries). Dr Ali touched on the importance of ATLS. As we can learn from the above story the issue is not as simple as we think. I will not scratch the issue of the role of Blood transfusion Service in this situation. Suffice it to say this is a colossal national challenge and deserves equal resources.I would like to express my disagreement with Dr Ali’s suggestion to exert our pressure on the Libyan Ministry of Health. I do not believe that we have any power to exert over the politicians

    Stochastic trajectory generation using particle swarm optimization for quadrotor unmanned aerial vehicles (UAVs)

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    The aim of this paper is to provide a realistic stochastic trajectory generation method for unmanned aerial vehicles that offers a tool for the emulation of trajectories in typical flight scenarios. Three scenarios are defined in this paper. The trajectories for these scenarios are implemented with quintic B-splines that grant smoothness in the second-order derivatives of Euler angles and accelerations. In order to tune the parameters of the quintic B-spline in the search space, a multi-objective optimization method called particle swarm optimization (PSO) is used. The proposed technique satisfies the constraints imposed by the configuration of the unmanned aerial vehicle (UAV). Further particular constraints can be introduced such as: obstacle avoidance, speed limitation, and actuator torque limitations due to the practical feasibility of the trajectories. Finally, the standard rapidly-exploring random tree (RRT*) algorithm, the standard (A*) algorithm and the genetic algorithm (GA) are simulated to make a comparison with the proposed algorithm in terms of execution time and effectiveness in finding the minimum length trajectory

    Seasonal change of thyroid histomorphological structure and hormone production in yellowfin seabream (Acanthopagrus latus) in the Persian Gulf

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    Seasonal changes of the thyroid gland structure and hormones secretion was examined in yellowfin seabream (Acanthopagrus latus) in the northwest of Persian Gulf (Musa creek). Thyroid gland composed of follicles scattered around the ventral aorta, near the gills. Follicular cells varied according to secretion of the gland during warm and cold seasons. Thyroid hormones (Triidothyronine [T3] and Thyroxine [T4]) were detected in the fish serum in levels ranged from 4.09-1.30 ng/mL for T3 and from 1.10-0.21 ng/mL for (T4) in the warm and cold seasons, respectively. The results showed that the height of thyroid epithelium and plasma concentration of thyroid hormones (thyroid activity) in A. latus increased significantly during spring and summer. The peak of these factors occurred in midsummer (August). Then, the thyroid activity decreased significantly during autumn and early winter from October to December according to decrease of temperature. T3 and T4 increased significantly from January to April

    Identification of new pillared-layered carbon nitride materials at high pressure

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    The compression of the layered carbon nitride C6N9H3·HCl was studied experimentally and with density functional theory (DFT) methods. This material has a polytriazine imide structure with Cl(-) ions contained within C12N12 voids in the layers. The data indicate the onset of layer buckling accompanied by movement of the Cl(-) ions out of the planes beginning above 10-20 GPa followed by an abrupt change in the diffraction pattern and c axis spacing associated with formation of a new interlayer bonded phase. The transition pressure is calculated to be 47 GPa for the ideal structures. The new material has mixed sp(2)-sp(3) hybridization among the C and N atoms and it provides the first example of a pillared-layered carbon nitride material that combines the functional properties of the graphitic-like form with improved mechanical strength. Similar behavior is predicted to occur for Cl-free structures at lower pressures

    Carbon fibers modified with polypyrrole for headspace solid phase microextraction of trace amounts of 2-pentyl furan from breath samples

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    This study introduces micrometric carbon strands as a suitable fiber for headspace solid phase microextraction. Compared to previous supports, carbon fibers have mechanical flexibility, wide thermal expansion, and a large surface area, which is an important factor in headspace solid phase microextraction. The electrophoretic technique was applied to modify the surface of stainless steel and carbon fibers with polypyrrole. Modified carbon fibers were used for extraction of 2-pentylfuran (2-PF) as a model analyte from patients� breath and coffee samples. 2-PF belongs to the furan family, which was suggested as a biomarker for Aspergillus fumigatus and was classified as a possible carcinogen. 2-PF can be found in many heat-processed foods and drinks. The separation and detection of the analyte was performed by gas chromatography coupled to mass spectrometry. The effective factors in the extraction performance of the analyte by carbon fiber supports were investigated and optimized. Under optimized extraction conditions (temperature, 20 °C; time, 15 min; desorption temperature, 200 °C; desorption time, 2 min; salt concentration, 10 w/v; and stirring rate, 700 rpm), the limit of detection was calculated as 0.05 ng mL�1, whereas repeatability and fiber-to-fiber reproducibility (RSD ) was found to be in the range of 3.2�4.1. The experimental results showed that the proposed fiber had greater extraction performance for 2-pentylfuran. © 201

    Utilization of waste as a constituent ingredient for enhancing thermal performance of bricks – a review paper

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    In view of the environmental regulations, practitioners have been inclined to use bricks with higher insulation capability, however with minimal attention to sustainable material composition, let alone waste material. From a research perspective, in the wake of the growing concerns for the environment, the use of waste material to develop bricks which can exhibit suitable characteristics attributed to the material composition has been on the rise. However, the extant literature on utilization of waste materials for brick mix design has neglected to provide detailed literature review on the influence of waste materials on the thermal performance of bricks. Methods: This paper provides detailed review of research conducted on thermal properties of bricks produced from various types of waste. Influence of the method of manufacturing and type of waste on thermal performance of bricks is discussed. A sustainability selection criteria format is provided to assist optimal decision making in considering alternative sustainable waste material. Findings: A sustainability selection criteria format is provided to assist optimal decision making in considering alternative sustainable waste material. Applications: The outcome of this paper can serve as a common reference for practitioners and researchers attempting to seek out solutions for further improving overall quality of thermally insulated waste-incorporated bricks, paving the way for more focused research on waste utilization in the development of more sustainable wall material based on the current brick production process

    Carbon nitride frameworks and dense crystalline polymorphs

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    We used ab initio random structure searching (AIRSS) to investigate polymorphism in C3N4 carbon nitride as a function of pressure. Our calculations reveal new framework structures, including a particularly stable chiral polymorph of space group P43212 containing mixed sp2 and sp3 bonding, that we have produced experimentally and recovered to ambient conditions. As pressure is increased a sequence of structures with fully sp3-bonded C atoms and three-fold-coordinated N atoms is predicted, culminating in a dense Pnma phase above 250 GPa. Beyond 650 GPa we find that C3N4 becomes unstable to decomposition into diamond and pyrite-structured CN2
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