In this study the Entrance Surface Dose (ESD) received by pediatrics patients undergoing chest, abdomen and skull X-ray examinations was estimated. The study was conducted in two hospitals in Najaf city where three radiographic systems were considered. The study participants were classified into four age groups 0-1 , 1-5 , 5-10 and 10-15 years. Calculations were performed using exposure factors, kVp, mAs and focal-skin distance, together with patient data age. The ESD was calculated for the involved patients who underwent an Antero-posterior (AP) chest, abdomen and skull X-ray examination. The resulted data were analyzed and compared with international dose references. For all studied radiographic examinations and all X-ray machines, the ESD increases with age. The lowest recorded radiation dose was from hospital 1 machine 2. In this facility ESD ranged from 19.93 µGy to 67.66 µGy for chest X-ray, from 39.03 µGy to 82.63 µGy for abdomen (AP), and from 35.47 µGy to 94.27 µGy for skull (AP). In contrast the highest dose levels are recorded from hospital 2 machine 1; the minimum ESD for chest X-ray is 247.51 µGy and the maximum is 2393.12 µGy; for abdomen X-ray the lowest ESD is 269.05 µGy and the highest value is 5106.15 µGy; and for skull X-ray minimum values is 430.96 µGy and the maximum value is 3072.77 µGy. In conclusion, for the considered pediatrics examinations, most of ESD values are within the international acceptable level and some are higher >100% .
Bipedal robotic mechanisms are unstable due to the unilateral contact passive joint between the sole and the ground. Hierarchical control layers are crucial for creating walking patterns, stabilizing locomotion, and ensuring correct angular trajectories for bipedal joints due to the system’s various degrees of freedom. This work provides a hierarchical control scheme for a bipedal robot that focuses on balance (stabilization) and low-level tracking control while considering flexible joints. The stabilization control method uses the Newton–Euler formulation to establish a mathematical relationship between the zero-moment point (ZMP) and the center of mass (COM), resulting in highly nonlinear and coupled dynamic equations. Adaptiv
... Show MoreAl-Naymi, N.A.Sh., H.A.S. AL-Nuaimi and M.R. Nashaat. 2022. Toxicity Stress of the Durah Power Plant Ash and its Effect on the Alga Chlorococcum humicola (Naeg) Rabenhorst 1868. Arab Journal of Plant Protection, 40(2): 188-192. https://doi.org/10.22268/AJPP-040.2.188192 This study illustrates the acute toxic effect of ash released from Durah power plant (DPP) on the biology of the phytoplankton species Chlorococcum humicola in Iraq. The results showed that the median lethal concentration for killing 50% of the Alga population (LC50) was 0.15 and 0.13 ppt (parts per thousand) for 24 and 48 hours exposure to crude ash concentrations, respectively. In contrast, no LC50 value was recorded for 72 and 96 hrs after exposure. The reduction
... Show MoreKarst aquifers in semi-arid regions are vital yet exceptionally vulnerable lifelines. This study investigates how tectonic, geomorphological, and climatic factors control the dynamics of karst springs in the El Menzel Causse (Middle Atlas, Morocco). Using an integrated approach that combines field investigations, remote sensing, and quantitative hydro-climatic analysis, we identify the mechanisms driving the system’s severe decline. Results indicated that the structural architecture of the major fault systems in the North Middle Atlas Fault (NMAF) and the Median Middle Atlas Fault (MMAF), governs the spatial distribution of more than 50 springs, which occur preferentially within highly permeable fault damage zones. However, the aquifer is
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