Recruitment of postlarval penaeid prawns in the Vellar estuary, South India

Abstract only.The northern bank of Vellar estuary (Parangipettai, India) is ideal for postlarval penaeid prawn recruitment. The annual recruitment, distribution and the substratum preference of postlarval immigrants at three different stations in the estuary were studied in detail. Among the postlarvae of Penaeus, P. (Fenneropenaeus) indicus was dominant followed by P. (Penaeus) monodon, P. (P.) semisulcatus, P. (F.) merguiensis and P. (Melicertus) latisulcatus. In Metapenaeus, postlarvae of M. monoceros were abundant followed by M. dobsoni, M. affinis, M. bre-vicornis and M. lysianassa. Two peaks were observed in the postlarval penaeid prawn population. In P (F.) indicus and P. (P.) monodon, the primary peak occurred from January to April and the secondary peak from July to September. In M. monoceros and M. dobsoni, the primary peak was from March to May and the secondary peak from August to September. The postlarvae of P. (F.) indicus, P. (P.) monodon, M. monoceros and M. dobsoni were available throughout the year while the others were seasonal. The distribution of postlarvae in the estuary is related to the type of substratum, salinity and temperature. The postlarval population declined during the northeast monsoon (November-December) and in peak summer (May-June). Their abundance decreased in the lower salinity areas of the upper reaches of the estuary

Blast mines: physics, injury mechanisms and vehicle protection.

Since World War II, more vehicles have been lost to land mines than all other threats combined. Anti-vehicular (AV) mines are capable of disabling a heavy vehicle, or completely destroying a lighter vehicle. The most common form of AV mine is the blast mine, which uses a large amount of explosive to directly damage the target. In a conventional military setting, landmines are used as a defensive force-multiplier and to restrict the movements of the opposing force. They are relatively cheap to purchase and easy to acquire, hence landmines are also potent weapons in the insurgents armamentarium. The stand-offnature of its design has allowed insurgents to cause significant injuries to security forces in current conflicts with little personal risk. As a result, AV mines and improvised explosive devices (IEDs) have become the most common cause of death and injury to Coalition and local security forces operating in Iraq and Afghanistan. Detonation of an AV mine causes an explosive, exothermic reaction which results in the formation of a shockwave followed by a rapid expansion of gases. The shockwave is mainly reflected by the soillair interface and fractures the soil cap overthe mine. The detonation products then vent through the voids in the soil, resulting in a hollow inverse cone which consists of the detonation gases surrounded by the soil ejecta. It is the combination of the detonation products and soil ejecta that interact with the target vehicle and cause injury to the vehicle occupants. A number of different strategies are required to mitigate the blast effects of an explosion. Primary blast effects can be reduced by increasing the standoff distance between the seat of the explosion and the crew compartment. Enhancement of armour on the base of the vehicle, as well as improvements in personal protection can prevent penetration of fragments. Mitigating tertiary effects can be achieved by altering the vehicle geometry and structure, increasing vehicle mass, as well as developing new strategies to reduce the transfer of the impulse through the vehicle to the occupants. Protection from thermal injury can be provided by incorporating fire resistant materials into the vehicle and in personal clothing. The challenge for the vehicle designer is the incorporation of these protective measures within an operationally effective platform.Published versio

Superficial venous patterns of the cubital fossa among volunteers from Hospital Kuala Lumpur

Introduction Cubital fossa is a space in anterior to the elbow which contains important vessels and nerves in the arm. Superficial veins of cubital fossa are commonly used for blood sampling, transfusions and for intravenous injections often under conditions of emergency. These veins are useful in arteriovenous fistula creation for hemodialysis. Besides that, they are used for creation of forearm flaps in plastic surgery. The arrangement of the superficial veins in the cubital fossa however is subjected to considerable variation. Different patterns of superficial cubital veins and their percentages of occurrence have been reported in various races. This prospective study among Malaysians from three races (Malays, Chinese and Indians) was planned since the superficial veins in the cubital fossa are important clinically and their arrangements are subject to racial variation. Objectives The aim of the study is to observe and describe the distribution of anatomical variations of the superficial veins of the cubital fossa among Malay, Chinese and Indian volunteers from Hospital Kuala Lumpur. Methodology and Study Design The study is designed as a descriptive cross-sectional survey involving a simple examination of the superficial veins of cubital fossa among volunteers from Hospital Kuala Lumpur. My sample is composed of three hundred volunteers from three major ethnicities Malays, Chinese and Indians aged from eighteen and above. I, myself performed the duplex ultrasound assessment with the guidance from my supervisors in the vascular unit HKL. The patterns of the veins were drawn onto a survey form. Results Based on my analysis, the commonest type of anastomosis seen was type 1 in both genders with female having 33.3% and male having 34.0% on the right cubital fossa and 32.0% in female and 34.0% in male on the left cubital fossa. Type 1 was the commonest among Malays and Indians. It was 40.0% and 37.0% of right and left cubital fossa in Malays. Indians meanwhile had 36.0% and 41.0% on the right and left cubital fossa. While in Chinese type 3 of anastomosis observed the most. It was 38.0% and 40.0% on right and left cubital fossa. The mixed type combination on both right and left cubital fossa was the highest prevalence in all 3 major ethnicities. There was no significant difference between gender and patterns but there was a significant difference in between ethnicities and patterns of cubital fossa. Conclusion Superficial veins of cubital fossa have their clinical importance. The understanding of patterns in genders, ethnicities and combination patterns of both cubital fossas will assist in clinical procedures. Duplex ultrasound has provided a great understanding of the anatomy of superficial veins of cubital fossa

The Spraying Technology on Iraqi Agricultural Researches

Many of the Iraqi agricultural researches are used spraying technique to add chemical products including pesticides and growth regulators. Various studies were performed to study the effect of these substances at different concentrations to improve plant production. In order to adopt specific criteria of spraying researches and to replicate them easily, it is a necessary to mention all information related to the spraying processes and regulations for improving sprayer’s performance by increasing the amount of pesticide deposited on the target. The current study aims to survey Iraqi researches in details and analyse them randomly. Also, to highlight on the importance of information applied in spraying techniques and its relationship with improving of agricultural production. The survey showed most of these researches does not mention sufficiently the basic information, especially in the spraying or calibrating processes. These processes are important to ensure the best distribution of spraying in the field depending on type of sprayer, nozzle type, and operating pressure. Also, some of these researches do not show the application rate of pesticide and the factors affected on it, which may lead to imbalance in homogenization of the pesticide distribution. This study recommended using a power sprayer to avoid the misapplication in droplets distribution in comparison with pack back sprayers, which have a complication in the operating pressure and nozzle height regulation. Another recommendation was a necessity to select the perfect nozzle type that agrees with the global publications

4-dimensional trajectory generation algorithms for RPAS mission management systems

This paper presents the algorithms enabling real-time 4-Dimensional Flight Trajectory (4DT) functionalities in Next Generation Mission Management Systems (NG-MMS), which are the core element of future Remotely Piloted Aircraft Systems (RPAS) avionics. In particular, the algorithms are employed for multi-objective optimisation of 4DT intents in various operational scenarios spanning from online strategic to tactical and emergency tasks. The adopted formulation of the multi-objective 4DT optimisation problem includes a number of environmental objectives and operational constraints. In particular, this paper describes the algorithm for planning of 4DT based on a multi-objective optimisation approach and the generalised expression of the cost function adopted for penalties associated with specific airspace volumes, accounting for weather, condensation trails and noise models

Cooperative and non-cooperative sense-and-avoid in the CNS+A context: a unified methodology

A unified approach to cooperative and noncooperative Sense-and-Avoid (SAA) is presented that addresses the technical and regulatory challenges of Unmanned Aircraft Systems (UAS) integration into nonsegregated airspace. In this paper, state-of-the-art sensor/system technologies for cooperative and noncooperative SAA are reviewed and a reference system architecture is presented. Automated selection of sensors/systems including passive and active Forward Looking Sensors (FLS), Traffic Collision Avoidance System (TCAS) and Automatic Dependent Surveillance - Broadcast (ADS-B) system is performed based on Boolean Decision Logics (BDL) to support trusted autonomous operations during all flight phases. The BDL adoption allows for a dynamic reconfiguration of the SAA architecture, based on the current error estimates of navigation and tracking sensors/systems. The significance of this approach is discussed in the Communication, Navigation and Surveillance/Air Traffic Management and Avionics (CNS+A) context, with a focus on avionics and ATM certification requirements. Additionally, the mathematical models employed in the SAA Unified Method (SUM) to compute the overall uncertainty volume in the airspace surrounding an intruder/obstacle are described. In the presented methodology, navigation and tracking errors affecting the host UAS platform and intruder sensor measurements are translated to unified range and bearing uncertainty descriptors. Simulation case studies are presented to evaluate the performance of the unified approach on a representative UAS host platform and a number of intruder platforms. The results confirm the validity of the proposed unified methodology providing a pathway for certification of SAA systems that typically employ a suite of non-cooperative sensors and/or cooperative systems

A laser obstacle warning and avoidance system for unmanned aircraft sense-and-avoid

This paper presents an overview of the research activities performed to develop a new scaled variant of the Laser Obstacle Avoidance and Monitoring (LOAM) system for small-to-medium size Unmanned Aircraft (UA) platforms. This LOAM variant (LOAM+) is proposed as one of the non-cooperative sensors employed in the UA Sense-and-Avoid (SAA) system. After a brief description of the LOAM system architecture, the mathematical models developed for obstacle avoidance and calculation of alternative flight path are presented. Additionally, a new formulation is adopted for defining the uncertainty volumes associated with the detected obstacles. Simulation case studies are carried out to evaluate the performances of the avoidance trajectory generation and optimisation algorithms, which demonstrate the ability of LOAM+ to effectively detect and avoid fixed low-level obstacles in the intended path

Bistatic LIDAR system for the characterisation of aviation-related pollutant column densities

In this paper we investigate an innovative application of Light Detection and Ranging (LIDAR) technology for aviation-related pollutant measurements. The proposed measurement technique is conceived for the high-resolution characterisation in space and time domains of aviation-related pollutant gases. The system performs Integral Path Differential Absorption (IPDA) measurement in a bistatic LIDAR measurement setup. The airborne component consists of a tuneable Near Infrared (NIR) laser emitter installed on an Unmanned Aircraft (UA) and the ground sub-system is composed by a target reference surface (calibrated for reflectance) and a differential transmittance measuring device based on a NIR Camera calibrated for radiance. The specific system implementation for Carbon Dioxide (CO2) measurement is discussed. A preliminary assessment of the error figures associated with the proposed system layout is performed

Multi-objective optimisation of aircraft flight trajectories in the ATM and avionics context

The continuous increase of air transport demand worldwide and the push for a more economically viable and environmentally sustainable aviation are driving significant evolutions of aircraft, airspace and airport systems design and operations. Although extensive research has been performed on the optimisation of aircraft trajectories and very efficient algorithms were widely adopted for the optimisation of vertical flight profiles, it is only in the last few years that higher levels of automation were proposed for integrated flight planning and re-routing functionalities of innovative Communication Navigation and Surveillance/Air Traffic Management (CNS/ATM) and Avionics (CNS+A) systems. In this context, the implementation of additional environmental targets and of multiple operational constraints introduces the need to efficiently deal with multiple objectives as part of the trajectory optimisation algorithm. This article provides a comprehensive review of Multi-Objective Trajectory Optimisation (MOTO) techniques for transport aircraft flight operations, with a special focus on the recent advances introduced in the CNS+A research context. In the first section, a brief introduction is given, together with an overview of the main international research initiatives where this topic has been studied, and the problem statement is provided. The second section introduces the mathematical formulation and the third section reviews the numerical solution techniques, including discretisation and optimisation methods for the specific problem formulated. The fourth section summarises the strategies to articulate the preferences and to select optimal trajectories when multiple conflicting objectives are introduced. The fifth section introduces a number of models defining the optimality criteria and constraints typically adopted in MOTO studies, including fuel consumption, air pollutant and noise emissions, operational costs, condensation trails, airspace and airport operations