A compact microstrip six-port reflectometer (SPR) with extended bandwidth is proposed in this paper. The design is based on using 16-dB multi-section coupled line directional couplers and a multi-section 3-dB Wilkinson power divider operating from 1 to 6 GHz. The proposed SPR employs only two calibration standards: a matched load and an open load. As compared to other dielectric substrates, fabricating the proposed SPR involves using a low-cost (FR4) substrate. A novel algorithm is also proposed to estimate the complex reflection coefficient over the frequency ranges at which the standard performance of the circuit components is not fully satisfied. The new algorithm is based on the circles’ intersection points, which have been derived from basic SPR equations, to estimate the complex reflection coefficient. To validate the SPR performance, a multiband microstrip patch antenna has been measured and the resulted reflection coefficient is compared with those obtained using a vector network analyzer (VNA). Results show that the proposed SPR provides a good estimation of the complex reflection coefficient within the frequency range of 1 GHz to 8 GHz. Owing to its compact size and ease of fabrication, the proposed reflectometer is suitable for various microwave broadband applications.
In this paper, the general framework for calculating the stability of equilibria, Hopf bifurcation of a delayed prey-predator system with an SI type of disease in the prey population, is investigated. The impact of the incubation period delay on disease transmission utilizing a nonlinear incidence rate was taken into account. For the purpose of explaining the predation process, a modified Holling type II functional response was used. First, the existence, uniform boundedness, and positivity of the solutions of the considered model system, along with the behavior of equilibria and the existence of Hopf bifurcation, are studied. The critical values of the delay parameter for which stability switches and the nature of the Hopf bifurcat
... Show MoreThe grasping stability of robotic manipulators is crucial to enable autonomous manipulation in an environment where robots are facing obstacles in their route, where abrupt changes in the robot’s speed are induced. These speed variations will produce forces affecting the robotic manipulator, hence its grasping stability. In this research, the grasping stability of a robotic manipulator that functions according to a frictional self-locking mechanism is investigated statically and dynamically. Both theoretical and experimental results showed that the grasped object size, weight, and its orientation inside the gripper have a great effect on grasping stability. Both the theoretical and experimental results indicated that the grasping object p
... Show MoreSerum levels of iron,copper,ceruloplasmin and transferrine were estimated in three groups of patients with ?- thalassemia: 24 patients have splenectomy thalassemia major, 29 patients have non splenectomy thalassemia major and 19 patients have thalassemia intermedia , data were compared to normal and pathological controls (anemia and minor). There were significant increase in trace element levels in all studied groups of pateints as compared to normal and pathological controls. Also there were a significant increase in ceruloplasmin levels,While the result revealed that there were a significant decrease in transferrine levels in all groups of patients studied as compared to normal and pathological controls. The result also indicate that the
... Show MoreAbstract A descriptive (retrospective) (a case-control) study was carried out at Al-Karama Teaching Hospital, Baghdad Teaching Hospital and Surgical Specialties Hospital, and Gastro-Intestinal Tract and Liver (GIT) Hospital for the period of December 1st, 2001 To March 15th 2002. To identify aspects of life-style that may contribute to the occurrence of peptic ulcer (P.U)as risk factors. And to find out the relationship between the demographic characteristic of the group. Non-probability (Purposive) sample of (100) cases who were admitted to the endoscopy department who were later on diagnosed as having
We present the notion of bipolar fuzzy k-ideals with thresholds (
Leigh's syndrome, or sub acute necrotizing encephalomyelopathy, is a rare inherited neurometabolic disease of infancy and early childhood with variable course and prognosis. Rarely, it occurs in juveniles and adults. The diagnosis is difficult and still remains to challenge the clinicians on the basis of history; hence the role of imaging is very essential. It is the neuroimaging, chiefly the Magnetic Resonance Imaging showing characteristic symmetrical necrotic lesions in the basal ganglia and/or brain stem that leads to the diagnosis. Late-onset varieties are rare and only few cases were reported all over the world. Here, I report a case of late onset (juvenile) Leigh syndrome presenting with an acute polyneuropathy. Neuroimaging confi
... Show MoreThe study investigated the behaviour of asphalt concrete mixes for aggregate gradations, according to the Iraqi specification using the Bailey method designed by an Excel spreadsheet. In mixing aggregates with varying gradations (coarse and fine aggregate), The Bailey method is a systematic methodology that offers aggregate interlocking as the backbone of the framework and a controlled gradation to complete the blends. Six types of gradation are used according to the bailey method considered in this study. Two-course prepared Asphalt Concrete Wearing and Asphalt Concrete binder, the Nominal Maximum Aggregate Sizes (NMAS) of the mixtures are 19 and 12.5 mm, respectively. The total number of specimens was 240 for both layers (15 samp
... Show MoreThe optimization of artificial gas lift techniques plays a crucial role in the advancement of oil field development. This study focuses on investigating the impact of gas lift design and optimization on production outcomes within the Mishrif formation of the Halfaya oil field. A comprehensive production network nodal analysis model was formulated using a PIPESIM Optimizer-based Genetic Algorithm and meticulously calibrated utilizing field-collected data from a network comprising seven wells. This well group encompasses three directional wells currently employing gas lift and four naturally producing vertical wells. To augment productivity and optimize network performance, a novel gas lift design strategy was proposed. The optimization of
... Show MoreThe Marshlands cover an area of about 24% of the land area of Iraq, which gives it special importance to the country with its resources, resources and human capabilities, and because the conditions of this region are different from other areas environmentally and living necessitates subject to certain design principles achieve sustainable environmental integration to maintain them from For future generations, the idea of research is crystallized by the interest of environmental organizations and urban designers in planning and establishing special laws to exploit the region environmentally, economically and tourism, especially after the current focus of the country's economic revival. T tourism and begin the development
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