Abstract: Rainfed agriculture is central to food security and livelihoods in Sudan, particularly in the semi-humid zones like Blue Nile region where rainfall patterns dictate crop success. This study analyzes growing season characteristics under five rainfall probability levels (20%,40%,50%,60%, and 80%） using 51 years (1971–2021） of rainfall and evapotranspiration data. Monthly rainy days were categorized by intensity, and seasonal rainfall amounts were analyzed across probabilistic classifications. Results indicate that the wet season （20% probability） receives the highest rainfall and growing season duration （154 days）, while the dry season （80%） is limited to 111 days. Rainfall distributions follow a bimodal pattern with predominance of low-intensity events and limited moderate rainfall. Pre-season and post-season rainfall showed significant implications for field accessibility, crop quality, and harvest efficiency. The study highlights the need for early preparation, improved crop varieties, and conservation agriculture techniques to mitigate climate risks and optimize productivity in the face of increasing variability.
Abstract: Amount of rainfall and period between rainfall events play a fundamental role in watering rainfed crops, hence improving productivity. Rainfed agriculture in Blue Nile region is one of the important areas in the Sudan. This study was conducted to evaluate the adequacy of seasonal rainfall compared to crop water requirements (ETc) for major rainfed crops grown in the Blue Nile region under five climatic conditions: wet, semi-wet, normal, semi-dry, and dry seasons. Daily climate data were obtained from Sudan Metrological Authority (SMA) records during the period from 1971 to 2021. Start, end and length of the growing season were determined for the five season types. Rainwater before, during and after the growing season were calculated. Seven summer crops were studied namely; sorghum, millet, sesame, sunflower, groundnuts, soya bean and cotton. Crops life cycle, length of growth stages and crop coefficients were used to calculate ETc. The results indicated that while early-season rainfall often meets crop demands, mid and late-season deficits are common, particularly in semi-dry and dry seasons. Though total rainfall was adequate, its uneven distribution underscores the necessity for using suitable crop management and soil moisture conservation practices. The study concluded that all studied crops are viable under current rainfall regimes in Blue Nile region, however, suitable crop management and soil moisture conservation practices has to be considered during mid and late season.
This work is an investigation into the effectiveness of controlled switching techniques in reducing switching over voltages on EHV transmission lines. The case study is the Sudanese 500 kV transmission line connecting generation at Merawi to the load centre at Khartoum (Sudan). The method used is modeling and simulation the line using MATLAB/SIMULINK. The results show that the phase-controlled switching technique is far superior to the Pre-insertion Resistor (PIR) method. It is also found that switching over-voltages are very much reduced when Metal-Oxide Surge Arresters (MOSA) are installed at the line ends and also when the transmission line is compensated.
An expression is developed to estimate the normalized polarizability of a dusty medium by taking into account the geometry factor of dust particles, the dust dielectric constant, and the probability of dust particles' axial ratios. This normalized polarizability reflects the overall impact of factors affecting the dusty medium's dielectric constant. The study assumes that the dust particles are ellipsoidal in shape with specific dimensions suggested by previous researchers. Elliptical integrals are used to determine the geometry factor of the dusty medium based on the distribution of axial ratios of the ellipsoidal dust particles. The Maxwell-Granett mixture model is utilized to determine the dusty medium's dielectric constant. Understanding the dielectric constant and particle geometry factor is crucial for effectively utilizing this model. The relationships between the geometry factors on the different semi-axis of the ellipsoidal dust particles are examined, and their respective domains are identified, along with an empirical relation connecting them. Numerical values are provided for the normalized polarizability at various frequencies within different frequency bands.
Internet of Underwater Things (IoUT) is one of the technologies that building smart cities , but it must overcome several challenges including environmental concerns ,connectivity barriers and system architecture complexities.This paper presents a performance analysis of Multi-Hop Internet of Underwater of Things Networks.we examine and assess the performance of multi hop IoUT networks in term of several key metrics ,including throughput, network efficiency, packet loss rate, and signal-to-noise ratio (SNR).The analysis provides valuable insight on the performance of multi hop IoUT networks, highlighting their performance and limitations.Keywords IoUT,Multi-Hop networks,underwater communication
