EVALUATION OF NUTRIENT SOLUTIONS PRODUCED FROM AQUEOUS EXTRACTS AND DECOMPOSITION PRODUCTS OF ORGANIC WASTE MATERIALS ON THE PLANT GROWTH PERFORMANCE IN HYDROPONICS

Hydroponic plant production involves the cultivation of plants in absence of soil. In this system, the supply of the plant root with water and nutritional elements occurs via a nutrient solution made of inorganic salts. Hydroponic plant cultivation often achieves higher yields, water use efficiencies and quality of crops compared with soil production. In addition, it renders the farming system independent from soil properties. However, the currently available systems rely on the steady input of non-renewable inorganic salts. Unlike soil-based systems, hydroponics, so far, do not offer feasible opportunities for recycling nutritional elements from within crop residues or organic waste materials. The main aim of this thesis was thus to elucidate the potential of producing nutrient solutions suitable for hydroponic plant cultivation from locally produced vegetable crop residues, commercial compost, and biosolids. In a first experiment, the release of soluble nutritional elements from the organic test materials was investigated over time and for different substrate/water ratios. Dried and ground organic substrate samples were placed into nylon mesh bags and allowed to extract and mineralize in aerated water for up to 23 days. The release of nutritional elements was monitored at intervals of three days and revealed that the highest amounts of soluble nutrients were present in the extraction solution between 3 and 6 days after the set-up of the trial. The use of one L of water for the extraction of six g of dry organic substrate resulted in the highest nutrient release. In a second experiment, the ability of two different nutrient solutions produced from organic waste materials to support the growth and element uptake of corn and cucumber seedlings was investigated. Either dry and ground biosolids or cucumber crop residues were extracted and mineralized for five days in aerated water before the extraction solution was used as a growth medium for hydroponic plant seedlings. A control treatment was supplied with a standard nutrient solution prepared from mineral fertilizer salts. The results revealed that all tested solutions well supported the growth of the seedlings. The solution prepared from biosolids was superior to the one deriving from cucumber leaves. Cucumber plants growing on the biosolid solution grew even better than those on the standard mineral nutrient solution. Corn plants performed best on the standard nutrient solution and the least on the one prepared from cucumber leaves. The results of this study suggest that recycling nutritional elements from organic waste materials into vii hydroponic plant production systems is well possible, using a relatively simple and cheap extraction procedure that could easily be upscaled. Biosolids might be particularly suitable in this respect, and hydroponic plant production might be a feasible way of valorizing this material, which is currently largely dumped into landfills

Optimum design of composite prestressed concrete girder railway bridges

This paper deals with the formulation of design optimisation of pretsressed concrete bridges. The bridge is of a slab-on-girder type, hence modeled as an equivalent orthotropic plate. The whole bridge system is considered as a simply supported right angle plate. Following linear elastic behaviour, the governing fourth order differential equation of the plate for patch load is solved in order to find out load distribution on the girders forming the bridge as well as the deflections and internal forces at critical sections of the whole bridge. The optimisation problem is formulated for various cross sectional geometries including rectangular, symmetrical I, unsymmetrical I, box, T and inverted T sections. The design variables are the main cross sectional dimensions, prestressing force and tendon eccentricity. The objective function comprises the cost of concrete material, formwork and prestressing steel tendons. The constraint functions are set to satisfy design requirements as per British Standards for bridges (BS 5400). Nonlinear optimisation method based on sequential unconstrained minimisation technique (SUMT) is employed to achieve optimum bridge configuration for specific design parameters of span length, concrete compressive strength and railway loading patterns. A purpose built computer program is set up to carry out the solution of the design optimisation problem efficiently in terms of time and effort. A typical example of unsymmetrical I-section having a small bottom flange as compared to the top flange width with composite deck effect is presented. The results show that the total cost increases as the span increases due to the increase of the initial prestressing force. Furthermore, the total cost decreases as the concrete compressive strength increases in spite of the increasing of the prestressing force. This is due to decrease of the overall depth, top and bottom flange widths, hence leading to a smaller girder size. Such finding will encourage engineers to adopt high strength concrete for bridges as it will help reducing not only the initial cost but also the life cycle cost of the bridge over its entire life

The effectiveness of using variable speed limit on the performance of an interrupted flow

The urban traffic congestion is getting worse with ever increasing urban population and vehicle ownership. The long queues at intersections and blockage of traffic on urban arterial roads become routine during the peak hours. Interrupted traffic flow through signalised intersections and arterial roads have badly been affected by these occurrences. Thus this paper examines the possibility of employing variable speed limit (VSL) for upstream traffic during the peak period to improve the traffic performance through signalised intersections as well as in urban arterials. The micro simulation software VISSIM was used to examine a hypothetical road network under VSL application. An expected traffic flow near capacity condition was simulated several times to see the effectiveness. Results show that for a reasonable period of time, the VSL application to the upstream traffic improve the traffic performance at immediate downstream intersections in terms of vehicle delay (16%), average queue length (18%) and average number of stops per vehicles (16%), while intersections located far from the VSL application has no or little effect. Similarly, the arterial performances have also been improved for a short period of time on the immediate downstream link in terms of density (13%), space mean speed (10%) and traffic flow (2%), the effective is negligible on the links located far. In addition a slight improvement was noticed to the total journey time on the immediate lin

Immunity-Based Framework for Autonomous Flight in GPS-Challenged Environment

In this research, the artificial immune system (AIS) paradigm is used for the development of a conceptual framework for autonomous flight when vehicle position and velocity are not available from direct sources such as the global navigation satellite systems or external landmarks and systems. The AIS is expected to provide corrections of velocity and position estimations that are only based on the outputs of onboard inertial measurement units (IMU). The AIS comprises sets of artificial memory cells that simulate the function of memory T- and B-cells in the biological immune system of vertebrates. The innate immune system uses information about invading antigens and needed antibodies. This information is encoded and sorted by T- and B-cells. The immune system has an adaptive component that can accelerate and intensify the immune response upon subsequent infection with the same antigen. The artificial memory cells attempt to mimic these characteristics for estimation error compensation and are constructed under normal conditions when all sensor systems function accurately, including those providing vehicle position and velocity information. The artificial memory cells consist of two main components: a collection of instantaneous measurements of relevant vehicle features representing the antigen and a set of instantaneous estimation errors or correction features, representing the antibodies. The antigen characterizes the dynamics of the system and is assumed to be correlated with the required corrections of position and velocity estimation or antibodies. When the navigation source is unavailable, the currently measured vehicle features from the onboard sensors are matched against the AIS antigens and the corresponding corrections are extracted and used to adjust the position and velocity estimation algorithm and provide the corrected estimation as actual measurement feedback to the vehicle’s control system. The proposed framework is implemented and tested through simulation in two versions: with corrections applied to the output or the input of the estimation scheme. For both approaches, the vehicle feature or antigen sets include increments of body axes components of acceleration and angular rate. The correction feature or antibody sets include vehicle position and velocity and vehicle acceleration adjustments, respectively. The impact on the performance of the proposed methodology produced by essential elements such as path generation method, matching algorithm, feature set, and the IMU grade was investigated. The findings demonstrated that in all cases, the proposed methodology could significantly reduce the accumulation of dead reckoning errors and can become a viable solution in situations where direct accurate measurements and other sources of information are not available. The functionality of the proposed methodology and its promising outcomes were successfully illustrated using the West Virginia University unmanned aerial system simulation environment

The Obligations of the Commercial Mandate towards the Mandate between the General Rules and Requirements of Commercial Dealing

The commercial mandate is one of the most widespread commercial contracts, that is why most legislations had to regulate it with special rules, making it a well noted commercial contract. Nevertheless the Iraqi legislature had a special method as he considered the commercial mandate as a business, but he did not assign it to certain provisions, which means that it will be subject to the provisions of the general rules. The commercial life has its characteristics and the commercial mandate has its own characteristics. What suits civil dealing does not necessarily suit the business. Accordingly, the unification of the provisions of civil and commercial mandates necessitates careful consideration, especially when it comes to the obligations of the commercial mandate. This raises the question whether it is possible for the general rules to meet the requirements of business. This research is an attempt to analyze the method of the Iraqi legislature in light of the reality of the Commercial businesses and parallel to the Emirate and Egyptian legislations in order to answer the question posed by the reality

Analysis and Comparison of Clothoid and Dubins Algorithms for UAV Trajectory Generation

The differences between two types of pose-based UAV path generation methods clothoid and Dubins are analyzed in this thesis. The Dubins path is a combination of circular arcs and straight line segments; therefore its curvature will exhibit sudden jumps between constant values. The resulting path will have a minimum length if turns are performed at the minimum possible turn radius. The clothoid path consists of a similar combination of arcs and segments but the difference is that the clothoid arcs have a linearly variable curvature and are generated based on Fresnel integrals. Geometrically, the generation of the clothoid arc starts with a large curvature that decreases to zero. The clothoid path results are longer than the Dubins path between the same two poses and for the same minimum turn radius. These two algorithms are the focus of this research because of their geometrical simplicity, flexibility, and low computational requirements.;The comparison between clothoid and Dubins algorithms relies on extensive simulation results collected using an ad-hoc developed automated data acquisition tool within the WVU UAV simulation environment. The model of a small jet engine UAV has been used for this purpose. The experimental design considers several primary factors, such as different trajectory tracking control laws, normal and abnormal flight conditions, relative configuration of poses, and wind and turbulence. A total of five different controllers have been considered, three conventional with fixed parameters and two adaptive. The abnormal flight conditions include locked or damaged actuators (stabilator, aileron, or rudder) and sensor bias affecting roll, pitch, or yaw rate gyros that are used in the feedback control loop. The relative configuration of consecutive poses is considered in terms of heading (required turn angle) and relative location of start and end points (position quadrant). Wind and turbulence effects were analyzed for different wind speed and direction and several levels of turbulence severity. The evaluation and comparison of the two path generation algorithms are performed based on generated and actual path length and tracking performance assessed in terms of tracking errors and control activity.;Although continuous position and velocity are ensured, the Dubins path yields discontinuous changes in path curvature and hence in commanded lateral accelerations at the transition points between the circular arcs and straight segments. The simulation results show that this generally leads to increased trajectory tracking errors, longer actual paths, and more intense control surface activity. The gradual (linear) change in clothoid curvature yields a continuous change in commanded lateral accelerations with general positive effects on the overall UAV performance based on the metrics considered. The simulation results show general similar trends for all factors considered. As a result, it may be concluded that, due to the continuous change in commanded lateral acceleration, the clothoid path generation algorithm provides overall better performance than the Dubins algorithm, at both normal and abnormal flight conditions, if the UAV mission involves significant maneuvers requiring intense lateral acceleration commands

A PARTIAL REPLICATION LOAD BALANCING TECHNIQUE FOR DISTRIBUTED DATA AS A SERVICE ON THE CLOUD

Data as a service (DaaS) is an important model on the Cloud, as DaaS provides clients with different types of large files and data sets in fields like finance, science, health, geography, astronomy, and many others. This includes all types of files with varying sizes from a few kilobytes to hundreds of terabytes. DaaS can be implemented and provided using multiple data centers located at different locations and usually connected via the Internet. When data is provided using multiple data centers it is referred to as distributed DaaS. DaaS providers must ensure that their services are fast, reliable, and efficient. However, ensuring these requirements needs to be done while considering the cost associated and will be carried by the DaaS provider and most likely by the users as well. One traditional approach to support a large number of clients is to replicate the services on different servers. However, this requires full replication of all stored data sets, which requires a huge amount of storage. The huge storage consumption will result in increased costs. Therefore, the aim of this research is to provide a fast, efficient distributed DaaS for the clients, while reducing the storage consumption on the Cloud servers used by the DaaS providers. The method I utilize in this research for fast distributed DaaS is the collaborative dual-direction download of a file or dataset partitions from multiple servers to the client, which will enhance the speed of the download process significantly. Moreover, I partially replicate the file partitions among Cloud servers using the previous download experiences I obtain for each partition. As a result, I generate partial sections of the data sets that will collectively be smaller than the total size needed if full replicas are stored on each server. My method is self-managed; and operates only when more storage is needed. I evaluated my approach against other existing approaches and demonstrated that it provides an important enhancement to current approaches in both download performance and storage consumption. I also developed and analyzed the mathematical model supporting my approach and validated its accuracy