Research Article
A Conceptual Model-based Design Approach for the Development of a New Hydraulic System Architecture for the UAV Class of Aircraft Application
Issue:
Volume 10, Issue 1, March 2025
Pages:
1-16
Received:
18 February 2025
Accepted:
28 February 2025
Published:
21 March 2025
Abstract: Advancements in aerospace system design are essential for improving efficiency, reducing weight, minimizing failures, and enhancing reliability while maintaining cost-effectiveness. This study presents a novel hydraulic system architecture for UAV-class aircraft, derived from conventional aircraft hydraulic designs. A conceptual modeling approach was employed to develop the system schematic, which was analyzed using LMS Amesim software to assess its performance under various conditions. The proposed system integrates a variable delivery piston hydraulic pump, an emergency accumulator, a bootstrap reservoir, and various hydraulic control valves. The design ensures optimal functionality while incorporating redundancy through an emergency landing gear extension mechanism. Hydraulic actuators control landing gear operations, with solenoid-operated selector valves regulating fluid flow based on operational needs. A shuttle valve allows automatic switching between the main hydraulic system and the emergency accumulator during system failures, ensuring reliability. LMS Amesim simulations validated key performance aspects, including pump pressure stabilization, accumulator charging behavior, landing gear actuation, and shuttle valve functionality. Results indicated stable pump operation at 206 bar, with emergency accumulator charging reaching 200 bar. The undercarriage system demonstrated smooth extension and retraction, with jack piston pressure transitions from 30 to 209 bar. The shuttle valve effectively switched between main and emergency hydraulic sources, enhancing system redundancy. Future improvements will focus on optimizing pump surge behavior, refining accumulator charging characteristics, integrating braking applications, and expanding hydraulic functionalities such as flap circuits. These enhancements will improve system robustness, efficiency, and fail-safe operation. This study demonstrates that conceptual modeling, combined with LMS Amesim simulations, is an effective approach for developing reliable hydraulic architectures for UAV-class aircraft, providing a strong foundation for future aerospace hydraulic advancements.
Abstract: Advancements in aerospace system design are essential for improving efficiency, reducing weight, minimizing failures, and enhancing reliability while maintaining cost-effectiveness. This study presents a novel hydraulic system architecture for UAV-class aircraft, derived from conventional aircraft hydraulic designs. A conceptual modeling approach w...
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Review Article
Lime Micro Dosing: A New Liming Strategy for Small Holder Farmers to Increase Crop Production and Productivity in Acid Soil Prone Areas of Ethiopia
Bikila Takala*
Issue:
Volume 10, Issue 1, March 2025
Pages:
17-23
Received:
14 January 2025
Accepted:
18 March 2025
Published:
31 March 2025
Abstract: Soil acidity has become a major constraint that threatens sustainable agricultural production in highlands of Ethiopia. Liming has been used as a soil amendments, to ameliorate the acidity problem, albeit it was challenging to apply recommended amount at once for small holder farmers due to inadequate availability, high cost, and poor infrastructure for lime transportation to the required agricultural land area. Hence, to address the problems, a new liming strategy and a precision technique referred to as microdosing, which involves application of small, affordable quantities of lime on an acid soil was evaluated across acid soil prone areas of Ethiopia. The objective of this paper was to summarize and document major research achievements recorded so far on different crops responses to lime micro dosing in acid soil prone areas of Ethiopia. Lime microdosing was evaluated at four lime application rates, including 6.25%, 12.5%, 25% and 33.3% of the recommended lime rate based on exchangeable acidity, which was compared to the traditional lime broadcasting strategy using 100% recommended lime rate in different regions of acid soil prone areas of Ethiopia. Averaged across all of the study, lime microdosing with 25% and 33.3% of recommended lime rate resulted in high yield for major crops (wheat, maize, barley, sorghum, fababean and soybean) in study area which was similar to that of the traditional lime broadcast techniques with a 100% recommended lime rate. Hence, the combined results of the study confirmed a promising positive influence of micro-dosing lime in ameliorating soil acidity and enhancing crop yield which could be suggested as a feasible new liming strategy for smallholder farmers seeking cost-effective and sustainable approaches to elevate agricultural productivity on acid soils. Therefore, micro-dose application of 25% recommended lime based on exchangeable acidity at planting time is the most economically affordable for smallholder farmers to improve soil acidity and increase crop production on acid soils of Ethiopia.
Abstract: Soil acidity has become a major constraint that threatens sustainable agricultural production in highlands of Ethiopia. Liming has been used as a soil amendments, to ameliorate the acidity problem, albeit it was challenging to apply recommended amount at once for small holder farmers due to inadequate availability, high cost, and poor infrastructur...
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