Position estimation performance evaluation of a linear lateration algorithm with an SNR-based reference station selection technique

The position estimation accuracy of the multilateration system lateration algorithm depends on several factors such as the number of stations deployed, time difference of arrival (TDOA) estimation technique and the choice of reference station. In this paper, a technique to select the suitable reference station for the lateration algorithm based on received signal-to-noise (SNR) at each of the deployed stations is presented. The position estimation performance analysis of the lateration algorithm with the reference selection technique is carried out and improvement in the position estimation accuracy is determined by comparing it with the convention approach of using fixed reference station. Monte Carlo simulation results when compared with the conventional approach based on a square station configuration showed a reduction in the position estimation error of about 20%.Keywords: reference selection, lateration algorithm, signal-to-noise-ratio, position estimatio

Mechanical and dynamic mechanical characterization of groundnut shell powder filled recycled high density polyethylene composites

Groundnut shell powder (GSP) reinforced recycled high density polyethylene composites were developed via melt mixing and compression moulding techniques. GSP was alkaline treated to increase its compatibility with the polymer matrix. The developed composites were subjected to mechanical properties test and thermal characterization using 242E dynamic mechanical analyzer. Results obtained indicated an enhancement in mechanical properties of the recycled high density polyethylene composites compared to the unreinforced (control sample). Similarly, dynamic mechanical properties results showed that the storage modulus of all the composites increase with increase in weight percentage of GSP incorporated. The energy dissipation in form of heat (loss modulus) and damping peaks (Tan ∂) values were found to be reduced with the incorporation of alkaline treated GSP which implies an improvement in thermal stability and load bearing capacity of the composites

Effect of groundnut shell powder on the viscoelastic properties of recycled high density polyethylene composites

In the quest to clean up the environment and produce economically viable materials from plastic wastes and readily available natural fibres, groundnut shell powder reinforced recycled high density polyethylene composite was prepared via two roll melt mixing and compression moulding technique. The dynamic mechanical properties of the composites such as storage modulus (E'), loss modulus (E''), and damping parameter (Tan ∂) were investigated using 242E dynamic mechanical analyzer in a temperature range from 30oC 100oC at a frequency of 1 Hz. It was found that the storage modulus of all the composites decrease with increase in temperature with composite containing 25%wt fibre having maximum E' value of 1158.47MPa compared to 1033.58MPa of the unreinforced recycled high density polyethylene. These results indicated that the thermal stability and load bearing capacity of the recycled high density polyethylene have been improved with the incorporation of groundnut shell powder. Scanning Electron micrographs showed better interfacial adhesion between treated groundnut shell powder in the polymer matrix; this explained the observed improvement in the viscoelastic properties of the composites.Keywords: Mechanical Properties, Groundnut Shell Powder, Recycled polyethylene, Viscolastic, Composites

Multiangulation position estimation performance analysis using a Bartlett’s Beamforming Method

In this work, a complete multiangulation system was developed and its performance in term of position estimation (PE) was determined. The developed system uses Bartlett’s beam forming method to estimate AOA of the signal impinging on the 16-element sensor array in a uniform linear array (ULA) geometry at each ground receiving station (GRS). The AOA measurements are then used as input to a linear angulation algorithm for PE. The PE accuracy of the developed system was determined using Monte Carlo simulation and compared with the directional rotating antenna multiangulation system using a square GRS configuration. Simulation results shows that the developed multiangulation PE error is 50% lower than that of the directional rotating antenna system. Furthermore, the PE error of the developed system is higher for emitting sources within the system coverage with position bearings within 610 to 1200 and 2400 to 3000 than other emitting source locations.Keywords: multiangulation system, position estimation, beam forming, Monte Carlo Simulation, position bearin

Effect of benzoyl chloride treatment on the mechanical and viscoelastic properties of plantain peel powder - reinforced polyethylene composites

Mechanical and dynamic mechanical analysis of plantain peel powder (PPP) reinforced polyethylene composites has been investigated. The PPP was treated with benzoyl chloride to reduce potential surface hindrances and bring about adhesion. The percentage fibre loading was varied from 0-25 % (0, 5, 10, 15, 20 and 25) respectively. Ultimate tensile strength, elastic modulus and hardness test data showed an improvement in mechanical properties of the treated fibre composites. Water absorption results indicated that benzoyl chloride treated PPP-recycled polyethylene composites have lower rate of water absorption than the untreated samples. Dynamic mechanical properties results showed that the storage modulus (E') of all the composites increase with increase in fibre loading and decrease with increase in temperature; composite containing 25 % (A25) PPP having the maximum E' value of 678 MPa compared to 576 MPa of the control sample. The results indicated that incorporation of plantain peel powder actually improved the thermal stability and the load bearing capacity of the recycled polyethylene composites.Keywords: Dynamic mechanical analysis, plantain peel powder, polyethylene composites, recycled low density polyethylen

Time of arrival 3-D position estimation using minimum ADS-B receiver configuration

The location from which a signal is transmitted can be estimated using the time it takes to be detected at a receiver. The difference between transmission time and the detection time is known as time of arrival (TOA). In this work, an algorithm for 3-dimensional (3-D) position estimation (PE) of an emitter using the minimum receiving stations configuration was developed. The TOA measurements estimated from three automatic surveillance dependent broadcast (ADS-B) receivers are used to evaluate the performance of the PE algorithm. The result shows that the triangular ADS-B receiver configuration is capable of 3-D PE for emitter locations within 190 km coverage radius and that the altitude estimation error is 2 km higher than the horizontal coordinate estimation error. Within the 3-D PE coverage of the ADS-B receiver, the maximum horizontal and altitude error expected are 0.12 km and 2.2 km respectively.Keywords: TOA, ADS-B, position estimation, minimum configuration, surveillanc

Urban malaria may be spreading via the wind: here’s why that’s important

No Abstrac

Evaluation of anticonvulsant activities of ethanol leaf extract of Hymenocardia acida Tul (euphorbiaceae) in mice and chicks

No AbstractKeywords: Hymenocardia acida, MEST, PTZ, 4-AP, Strychnin

Mechanical, Spectroscopic and Micro-structural Characterization of Banana Particulate Reinforced PVC Composite as Piping Material

A banana particulate reinforced polyvinyl chloride (PVC) composite was developed with considerabley low cost materials having an overall light-weight and good mechanical properties for potential application as piping material. The specimen composite material was produced with the banana (stem) particulate as reinforcement using compression molding. Results showed that density and elastic Modulus of the composite decreases and increases respectively with increasing weight fraction of the particulate reinforcement. The tensile strength increased to a maximum of 42 MPa and then decreased steadily. The composition with optimum mechanical property (42 MPa) was determined at 8, 62 and 30 % formulation of banana stem particulates (reinforcement), PVC (matrix) and Kankara clay (filler) respectively with corresponding percentage water absorption of 0.79 %, Young’s Modulus of 1.3 GPa, flexural strength of 92 MPa and density of 1.24 g/cm3. Fourier Transform Infrared (FTIR) analysis of the constituents showed identical bands within the range 4000–1000 cm-1 with renown research work. Scanning Electron Microscopy (SEM) result showed fairly uniform distribution of constituents’ phases. X-Ray Fluorescence (XRF) confirms the X-ray diffraction (XRD) result of the presence of minerals of kaolinite, quartz, rutile and illite in the kaolin clay. Comparison with conventional piping materials showed the composite offered a price savings per meter length of 84 % and 25 % when compared with carbon steel and PVC material