Investigating the Effect of Different Roughness on Velocity Pattern at a Reach of Shatt-Al-Arab

Shatt al-Arab River is the only international navigational river in Iraq, extending from the city of Qurna to its mouth in the Arabian Gulf at the city of Al-Fao within the governorate of Basrah for a length of approximately 204 km. Its width ranges from 400 m to 2000 m and its depth ranges from 8 m to 20 m. Since many years Shatt al-Arab River suffer from scouring at the right side (Iraqi side), that is led to displace the borders between Iraq and Iran (Al- Thalweg Line) towards Iraqi territory and thus led to loss of Iraqi land to Iran. Reducing flow velocity along the Iraqi side can led to reducing or preventing erosion in the right bank. Increasing the riverbed roughness will reduce the velocity of flow and then reducing the erosion. This principle was adopted in this study. In this research, a reach of Shatt Al-Arab with a length of 2.5 km located at 34 km northern Fao city was selected to represent the study area. A small area at the upstream of the reach mentioned earlier (700 m length) was selected and called strip in order to change the bed roughness for three different heights. This scenario was simulated with full scale (prototype scale) to investigate the effect of increasing the bed roughness on the velocity pattern at river cross sections and along the reach. The simulation done by using 3D numerical modeling CFD solver (ANSYS fluent 19). For each allocated area, as increasing the roughness height (ks), the longitudinal velocity (v) decreased at the right side by about 10% to 70% and increased by about 5% to 260% at left side along the river reach.

Smart Spray Analytical System for Orchard Sprayer Calibration: A-Proof-of-Concept and Preliminary Results

Efficient chemical spray applications are vital to reduce off-target drift, economic losses to tree fruit growers, and negative environmental impacts. It is thus important to adequately calibrate and adjust orchard sprayers for intended applications. This technical note describes the design, prototyping, and field evaluation of a sensor-based smart spray analytical system (SSAS). The SSAS is equipped with units for spray capturing and volumetric quantification, air-assist velocity measurement, system actuation and control, and data acquisition and wireless transmission. The spray liquid and air-assist velocity quantification units are assembled on a custom-made mobile frame for vertical stop-and-go movement to provide measurements at eight distinct sampling heights above ground level. The data acquisition and transmission units autonomously log the data on-board and transmit wirelessly to a receiving computer with time and height stamps for real-time graphical visualization. All these autonomous processes are guided by a custom programmable single-board computer. The SSAS was preliminarily evaluated for spray liquid and air-assist velocity pattern assessment of an air-assisted orchard sprayer in four sets of spray trials. An average spray liquid recovery of 14.03% and pertinent coefficient of variation (CV) of 10.73% were observed. An average CV of 11.93% was observed in the air-assist velocity patterns. Overall, the SSAS provided measurements within acceptable ranges of variation. This system can thus minimize the experimental errors, time, and efforts involved in conventional assessments of sprayer attributes, thereby providing a reliable solution for orchard sprayer calibration and adjustment. Keywords: Air-assist velocity pattern, Airblast sprayer calibration, Data storage and transmission, Graphical visualization, Smart spray analytical system, Spray liquid pattern.

Analysis of Velocity Pattern of a Power-Assisted Mobile Robot

This paper aims to analyze the velocity pattern of a power-assisted mobile robot when the operator performs operation without any discomfort. Power-assist systems for mobile robots such as wheelchairs and conveyance carriers are extremely effective in alleviating the physical burden on operators when they carry heavy objects. Although the velocity control based power-assist system has an advantage that it can be easily realized, the problem lies in that the system becomes unstable when the operator has high stiffness. Variable impedance control based on impedance estimation of the operator is effective at solving this problem. To realize operator impedance estimation, it is necessary to know the intended robot’s motion of a person. In this study, as a preliminary step to estimate the operator’s impedance, the velocity pattern when the operator performs natural operation of the robot through the power-assist system is analyzed. The results confirm that the natural velocity pattern can be approximated by a velocity pattern connecting two minimum jerk trajectories.