Gaussian beam divergence using paraxial approximation

Gaussian beam intensity follows a normal distribution curve in free space. As it propagates, the divergence and the width increase with distance. Using paraxial approximation, the effect of the distance on the intensity, width, radius of curvature and divergence was investigated. Matlab software was used for characteristics parameters calculation. The divergence angle range (26.67o≤ θ ≤35.85o) was obtained at a distance between 3mm and 4mm, and compared with the divergence angle range (43o≤ θ ≤53o) obtained experimentally for the distance between 3mm and 4.5mm. The result obtained in this work indicates smaller angles of divergence that can produce a better beam quality and intensity. Finally, this will serve as a great importance for application such as pointing, free space optical communication etc.Keyword: Gaussian beam, Paraxial approximation, Beam divergence, Normal distribution curve

Robust, Resilient and Reliable Architecture for V2X Communication

The new developments in mobile edge computing (MEC) and vehicle-to-everything (V2X) communications has positioned 5G and beyond in a strong position to answer the market need towards future emerging intelligent transportation systems and smart city applications. The major attractive features of V2X communication is the inherent ability to adapt to any type of network, device, or data, and to ensure robustness, resilience and reliability of the network, which is challenging to realize. In this work, we propose to drive these further these features by proposing a novel robust, resilient and reliable architecture for V2X communication based on harnessing MEC and blockchain technology. A three stage computing service is proposed. Firstly, a hierarchcial computing architecture is deployed spanning over the vehicular network that constitutes cloud computing (CC), edge computing (EC), fog computing (FC) nodes. The resources and data bases can migrate from the high capacity cloud services (furthest away from the individual node of the network) to the edge (medium) and low level fog node, according to computing service requirements. Secondly, the resource allocation filters the data according to its significance, and rank the nodes according to their usability, and selects the network technology according to their physical channel characteristics. Thirdly, we propose a blockchain-based transaction service that ensures reliability. We discussed two use cases for experimental analysis, plug- in electric vehicles in smart grid scenarios, and massive IoT data services for autonomous cars. The results show that car connectivity prediction is accurate 98% of the times, where 92% more data blocks are added using micro-blockchain solution compared to the public blockchain, where it is able to reduce the time to sign and compute the proof-of-work (PoW), and deliver a low-overhead Proof-of-Stake (PoS) consensus mechanism. This approach can be considered a strong candidate architecture for future V2X, and with more general application for everything- to-everything (X2X) communications

Propiedades químicas del suelo y producción de maíz tras la aplicación de enmiendas orgánicas e inorgánicas a un suelo ácido en el suroeste de Nigeria

A factorial experiment with a randomised complete block design (three replicates) was performed to determine the effects of poultry manure (PM), lime (L) and NPK 15-15-15 fertilizer on soil chemical properties, and to determine the effects of their combinations on soil productivity and maize yield. The factors were PM (0, 5 and 10 Mg/ha), L as CaCO3 (0 and 250 kg/ha) and NPK 15-15-15 (0 and 100 kg/ha). The soil had a loamy sand texture. The application of L and PM increased the surface soil pH in a similar fashion. In both years of the experiment, the effective cation exchange capacity (ECEC) of the soil after the combined application of 10 Mg/ha PM, L and NPK was significantly higher than after the individual application of L or NPK or their combination (5.75-7.65 cmol/kg compared to 3.36-4.57 cmol/kg). The application of 10 Mg/ha PM with L and/or NPK reduced the possibility of Mn toxicity, with soil levels ranging from 108 to 136 mg/kg. The combined use of the three amendments gave the highest leaf nutrient concentrations. The highest maize grain yield (4.62 Mg/ha) was obtained with L + 10 Mg/ha PM; with no amendment the grain yield was 1.9 Mg/ha. The application of PM enhanced the effects of L and NPK in improving soil productivity. However, separate applications of 5 and 10 Mg ha-1 PM similarly affected soil productivity; the sandy nature of the soil at depths of 0-20 cm seems to have prevented differences between the two rates from becoming manifested.Para determinar los efectos del abono de residuos de aves (PM), de cal (L) y de fertilizante NPK 15-15-15 sobre las propiedades químicas del suelo, y determinar los efectos de sus combinaciones sobre la productividad del suelo y producción del maíz, se llevó a cabo un experimento factorial con un diseño en bloques al azar (tres réplicas). Los factores fueron PM (0, 5 y 10 Mg/ha), L como CaCO3 (0 y 250 kg/ha) y NPK 15-15-15 (0 y 100 kg/ha). El suelo tenía una textura franco arenosa. La aplicación de L y PM aumentó el pH de la superficie del suelo de forma parecida. En los dos años del experimento, la capacidad de cambio de cationes efectiva (ECEC) del suelo tras la aplicación combinada de 10 Mg/ha PM, L y NPK fue significativamente superior que la de la aplicación individual de L ó NPK o una combinación de ambos (5,75-7,65 cmol/kg vs. 3,36-4,57 cmol/kg). La aplicación de 10 Mg/ha PM con L y/o NPK redujo la posibilidad de toxicidad con Mn, con niveles de suelo de 108-136 mg/kg. El uso combinado de las tres enmiendas produjo las concentraciones de nutrientes en hoja más altas. La producción de grano más alta en maíz (4,62 Mg/ha) se obtuvo con L + 10 Mg/ha PM; sin enmiendas se obtuvo 1,9 Mg/ha. La aplicación de PM aumentó los efectos de L y NPK en la mejora de la productividad del suelo. Sin embargo, aplicaciones separadas de 5 y 10 Mg/ha de PM afectaron de forma similar a la productividad del suelo; la naturaleza arenosa del suelo a profundidades de 0-20 cm parece disminuir las diferencias entre las dos dosis

Simulation of the effect of bit assignment to multi-hypothesis pictures per group for motion compensated video compression (MCVC)

This paper describes the Lagrange based formulation of bit-assignment for multi-hypothesis frames over number of pictures in a group for motion compensated video compression. Theoretical insight on bit assignment is accomplished by applying Lagrange multiplier and its cost function for a real-time computational analysis. Video signals are compressed at optimal bit allocation for qualitative reconstruction at the decoder (receiver) depending upon the number of hypothesis used in coding the signal. This has made multi-hypothesis motion compensation (MHMC) a great process in the prediction of the actual signal through the combination of more than one motion compensated prediction (MCP). Optimal Bits were allocated to multi-hypothesis frames using MATLAB to optimize the number of hypothesis frames per group of pictures (GOP) decoded for an improved signal compression. Simulation results show that an optimal bit assignment of the range 0.089 bpp to 0.159 bpp was realized with eight numbers of hypotheses frames per (GOP). This implies that varying number of hypotheses actualizes optimal bit assignment for motion compensation. This shows a qualitative signal compression performance analysis for high technology motion pictures in communication services and storage processes. It also addresses a better prediction due to greater time correlation between hypotheses and helps in the improvement of coding and reconstruction quality of video signals.Key words: Bit-rate, frame, Group of Pictures (GOP), Motion Compensation,multi-hypothesis, Video Compression

Soil chemical properties and maize yield after application of organic and inorganic amendments to an acidic soil southwestern Nigeria

A factorial experiment with a randomised complete block design (three replicates) was performed to determine the effects of poultry manure (PM), lime (L) and NPK 15-15-15 fertilizer on soil chemical properties, and to determine the effects of their combinations on soil productivity and maize yield. The factors were PM (0, 5 and 10 Mg ha-1), L as CaCO3 (0 and 250 kg ha-1) and NPK 15-15-15 (0 and 100 kg ha-1). The soil had a loamy sand texture. The application of L and PM increased the surface soil pH in a similar fashion. In both years of the experiment, the effective cation exchange capacity (ECEC) of the soil after the combined application of 10 Mg ha-1 PM, L and NPK was significantly higher than after the individual application of L or NPK or their combination (5.75-7.65 cmol kg-1 compared to 3.36-4.57 cmol kg-1). The application of 10 Mg ha-1 PM with L and/or NPK reduced the possibility of Mn toxicity, with soil levels ranging from 108 to 136 mg kg-1. The combined use of the three amendments gave the highest leaf nutrient concentrations. The highest maize grain yield (4.62 Mg ha-1) was obtained with L + 10 Mg ha-1 PM; with no amendment the grain yield was 1.9 Mg ha-1. The application of PM enhanced the effects of L and NPK in improving soil productivity. However, separate applications of 5 and 10 Mg ha-1 PM similarly affected soil productivity; the sandy nature of the soil at depths of 0-20 cm seems to have prevented differences between the two rates from becoming manifested.Para determinar los efectos del abono de residuos de aves (PM), de cal (L) y de fertilizante NPK 15-15-15 sobre las propiedades químicas del suelo, y determinar los efectos de sus combinaciones sobre la productividad del suelo y producción del maíz, se llevó a cabo un experimento factorial con un diseño en bloques al azar (tres réplicas). Los factores fueron PM (0, 5 y 10 Mg ha-1), L como CaCO3 (0 y 250 kg ha-1) y NPK 15-15-15 (0 y 100 kg ha-1). El suelo tenía una textura franco arenosa. La aplicación de L y PM aumentó el pH de la superficie del suelo de forma parecida. En los dos años del experimento, la capacidad de cambio de cationes efectiva (ECEC) del suelo tras la aplicación combinada de 10 Mg ha-1 PM, L y NPK fue significativamente superior que la de la aplicación individual de L ó NPK o una combinación de ambos (5,75-7,65 cmol kg-1 vs. 3,36-4,57 cmol kg-1). La aplicación de 10 Mg ha-1 PM con L y/o NPK redujo la posibilidad de toxicidad con Mn, con niveles de suelo de 108-136 mg kg-1. El uso combinado de las tres enmiendas produjo las concentraciones de nutrientes en hoja más altas. La producción de grano más alta en maíz (4,62 Mg ha-1) se obtuvo con L + 10 Mg ha-1 PM; sin enmiendas se obtuvo 1,9 Mg ha-1. La aplicación de PM aumentó los efectos de L y NPK en la mejora de la productividad del suelo. Sin embargo, aplicaciones separadas de 5 y 10 Mg ha-1 de PM afectaron de forma similar a la productividad del suelo; la naturaleza arenosa del suelo a profundidades de 0-20 cm parece disminuir las diferencias entre las dos dosis

Farmer preferences and market vaues of cattle breeds of west and central Africa

World agriculture is based on a small number of animal species and a decreasing number of breeds within each species. Several breeds of West African shorthorn cattle (Bos taurus brachyceros) are now at high risk of extinction due to interbreeding. The West African shorthorn breeds are particularly important resources because of their superior abilities to resist diseases, particularly trypanosomosis, and be productive under high humidity, heat stress, water restriction and with poor quality feed. A study was undertaken in the derived savanna area of southwest Nigeria to determine the prospects for conservation through use and possible improvement of the Muturu, a West African shorthorn breed known to be in decline throughout southern Nigeria. An analysis of farmers' breeding practices and breed preferences confirmed a strong trend away from Muturu and identified the traits farmers find least desirable about the Muturu relative to other breeds. An analysis of cattle market prices found small, but significant, price differences by breed. The best hopes for increased utilization likely in other areas of West Africa, such as southeast Nigeria, where the Muturu is better suited to the farming systems and there is a large market for this breed

Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

Application of stable isotopes in soil studies has improved quantitative evaluation of evaporation and other hydrological processes in soil. This study was carried out to determine the effect of tillage on evaporative loss of water from the soil. Zero tillage and conventional tillage were compared. Suction tubes were installed for soil water collection at the depths 0.15, 0.50, and 1.0 m by pumping soil water with a peristaltic pump. Soil water evaporation was estimated using stable isotopes of water. The mean isotopic composition of the soil water at 0.15 m soil depth were -1.15 parts per thousand (delta O-18) and -0.75 parts per thousand (delta D) and were highly enriched compared with the isotopic compositions of the site precipitation. Soil water stable isotopes (delta O-18 and delta D) were more enriched near the surface under zero tillage while they were less negative down the profile under zero tillage. This suggests an occurrence of more evaporation and infiltration under conventional then zero tillage, respectively, because evaporative fractionation contributes to escape of lighter isotopes from liquid into the vapour phase leading to enrichment in heavy isotopes in the liquid phase. The annual evaporation estimated using the vapour diffusion equation ranges from 46-70 and 54-84 mm year(-1) under zero and conventional tillage, respectively, indicating more evaporation under conventional tillage compared with zero tillage. Therefore, to reduce soil water loss, adoption of conservation tillage practices such as zero tillage is encouraged