Applied Science Private University

About: Applied Science Private University is a education organization based out in Amman, Jordan. It is known for research contribution in the topics: Population & Catalysis. The organization has 4124 authors who have published 5299 publications receiving 116167 citations.

Modelling climate change impacts on maize yields under low nitrogen input conditions in sub-Saharan Africa.

Abstract: Smallholder farmers in sub‐Saharan Africa (SSA) currently grow rainfed maize with limited inputs including fertilizer Climate change may exacerbate current production constraints Crop models can help quantify the potential impact of climate change on maize yields, but a comprehensive multimodel assessment of simulation accuracy and uncertainty in these low‐input systems is currently lacking We evaluated the impact of varying [CO2], temperature and rainfall conditions on maize yield, for different nitrogen (N) inputs (0, 80, 160 kg N/ha) for five environments in SSA, including cool subhumid Ethiopia, cool semi‐arid Rwanda, hot subhumid Ghana and hot semi‐arid Mali and Benin using an ensemble of 25 maize models Models were calibrated with measured grain yield, plant biomass, plant N, leaf area index, harvest index and in‐season soil water content from 2‐year experiments in each country to assess their ability to simulate observed yield Simulated responses to climate change factors were explored and compared between models Calibrated models reproduced measured grain yield variations well with average relative root mean square error of 26%, although uncertainty in model prediction was substantial (CV = 28%) Model ensembles gave greater accuracy than any model taken at random Nitrogen fertilization controlled the response to variations in [CO2], temperature and rainfall Without N fertilizer input, maize (a) benefited less from an increase in atmospheric [CO2]; (b) was less affected by higher temperature or decreasing rainfall; and (c) was more affected by increased rainfall because N leaching was more critical The model intercomparison revealed that simulation of daily soil N supply and N leaching plays a crucial role in simulating climate change impacts for low‐input systems Climate change and N input interactions have strong implications for the design of robust adaptation approaches across SSA, because the impact of climate change in low input systems will be modified if farmers intensify maize production with balanced nutrient management

Fuzzy sets analysis for leak detection in infrastructure systems: a proposed methodology

Abstract: This paper aims to propose a methodology for detecting problems in environmental and infrastructure systems using a fuzzy set technique. The proposed methodology was applied to a case study in water distribution systems for validation. Relative weights for three scenarios of leak detection were used, i.e. leakage, possible leakage, and no leakage. The study reveals that the major factors that affect leakage are: pipe age, pipe material, operational aspects, and demand patterns.

A Survey on MAC Protocol Approaches for Underwater Wireless Sensor Networks

Abstract: Since communications in the Underwater Wireless Sensor Networks (UWSNs) have limited resources and capabilities, designing an efficient and reliable Media Access Control (MAC) protocol for UWSNs faces many challenges. UWSNs have limited bandwidth, power, memory, long propagation delay, high Bit Error Rate (BER), and unreliable communication. Current MAC protocols that have been designed for Terrestrial Wireless Sensor Networks (TWSNs) are not suitable for UWSNs. While the software-based mechanisms promise many benefits to TWSN, few proposal designs introduced MAC protocols based on software-based mechanisms for UWSNs. The software-based approach is a flexible one that helps to change system parameters of all layers with no need for additional hardware. In this article, we focus on presenting a survey of the state of the art of the recent development of MAC protocols for UWSNs from recent literature followed by a discussion of the characteristics and limitations of each MAC protocol. This article also evaluates the channel transmission and compares the performance of four different MAC protocol approaches to identify the most suitable one for the underwater oil/gas pipelines application in terms of end-to-end delay, energy consumption, Packet Delivery Ratio (PDR), the total number of collisions, and throughput using different network loads.