Soil moisture is a vital factor affecting the hydrological cycle and the evolution of soil and geomorphology, determining the formation and development of the vegetation ecosystem. The previous studies mainly focused on the effects of different land use patterns and vegetation types on soil hydrological changes worldwide. However, the spatial heterogeneity and driving factors of soil gravimetric water content in alpine regions are seldom studied. On the basis of soil sample collection, combined with geostatistical analysis and the geographical detector method, this study examines the spatial heterogeneity and driving factors of soil gravimetric water content in the typical alpine valley desert of the Qinghai–Tibet Plateau. Results show that the average value of soil gravimetric water content at different depths ranges from 3.68% to 7.84%. The optimal theoretical models of soil gravimetric water content in 0–50 cm layers of the dune are different. The nugget coefficient shows that the soil gravimetric water content in the dune has a strong spatial correlation at different depths, and the range of the optimal theoretical model of semi-variance function is 31.23–63.38 m, which is much larger than the 15 m spacing used for sampling. The ranking of the influence of each evaluation factor on the alpine dune is elevation > slope > location > vegetation > aspect. The interaction detection of factors indicates that an interaction exists among evaluation factors, and no factors are independent of one another. In each soil layer of 0–50 cm, the interaction among evaluation factors has a two-factor enhancement and a nonlinear enhancement effect on soil gravimetric water content. This study contributes to the understanding of spatial heterogeneity and driving factors of soil moisture in alpine deserts, and guidance of artificial vegetation restoration and soil structure analysis of different desert types in alpine cold desert regions.

The northwest arid region (NAR) of China, located in a cold region, has been experiencing extreme weather and runoff events for years. Summer (from June to August) is the main season for forming runoff in this region. Summer runoff is contributed by glacial runoff in addition to precipitation in glacierized basins. The upper basins of Hei River, Shule River, Kaidu River, and Manas River with different glacier coverage and available daily average discharge data were selected in this study. Two runoff indices—maximum discharge difference (MDD) and accumulated direct discharge (ADD)—were defined and calculated for each runoff event in the time series of daily average discharge during 1961–2007. To provide scientific knowledge for managing water resources and preventing disasters, the relationships between summer runoff indices and their associated precipitation and temperature variables were obtained by linear regression analysis. Results suggest that the regulation of glacier on runoff is more significant with the increase of glacier coverage.

Moving towards more electric aircraft, a hybrid configuration of actuators gives us an opportunity to introduce electro-hydrostatic actuators in the primary flight control system. Hybrid configuration gives birth to force fighting problems that must be addressed. Force fighting will occur when both actuators are actively controlled. This paper presents different strategies for position synchronization of hybrid configuration involve HA and EHA in active/active mode. First a model is made and its accuracy is checked in mat lab\Simulink. Then four position synchronization strategies have been presented. The first one uses a PID controller to balance position loop dynamics. Second strategy uses self-tuning Fuzzy PI controller to control position loop dynamics and PID controller to improve load rejection performance. The third and fourth uses PID for position loop dynamics and Pre-compensators to equalize force dynamics. It has found that every strategy is better, according to its own desired application. Every strategy has its own advantage and disadvantage. However the PID controller strategy is better with respect to property of Segregation and HA Pre-compensator strategy is better with respect to reduction in force fighting. Self-tuning fuzzy PI controller strategy and EHA compensator strategy are better with respect to efficiency (making EHA faster improves efficiency of the system) of the system.

In order to improve the performance of multi-stage cylinder to achieve rapid and steady extension, a novel throttling-inside-piston multi-stage hydraulic cylinder is proposed without changing physical size and piston working strokes of the traditional sequential multi-stage hydraulic cylinder. Based on internal structure optimal design and basic size parameter calculation, the mathematical model of the proposed throttling-inside-piston multi-stage hydraulic cylinder is studied using multi-rigid-body and impact-recovery dynamic theory. Then, the diameters of the orifices within the pistons are optimized using constraint optimization technique. Comparative simulation results show that the new type of throttling-inside-piston multi-stage hydraulic cylinder can significantly enhance the rapidity and steadiness for the erecting system.

This paper focuses on a robust control method applied to an electro-Hydraulic Load Simulator (HLS) acting on a special aerodynamic load. Owing to the high-speed on-off valve, some pneumatic aircraft actuators have inherent high-frequency motion disturbance that reduces the dynamic tracking performance. Through combining velocity synchronising decoupling compensation and equivalent disturbance observers, this paper presents a Dynamic Robust Compensation (DRC) to achieve high precision load simulation. The experiments indicate that the velocity synchronising decoupling is used to restrain strong disturbance, whereas the robust compensator is adopted to reduce the remaining extraneous torque from motion flutter efficiently further.