This paper investigate a sensorless speed control of a separately excited dc motor fed from a buck type dc-dc converter. The control system is designed in digital technique by using a two dimension look-up table. The performance of the drive system was evaluated by digital simulation using Simulink toolbox of Matlab.
In this research the effect of grain size and effect of La2O3 doping on densification rate for the initial and intermediate stages of sintering were studied .The experimental results for α – cristobilite powder are modeled using ( L2-Regression ) technique in studying the effect of grain size and La2O3 doping using three particles size (6.12, 8.92, 13.6 ) µm, with undoped initial powder and with La2O3 doping . The mathematical simulation showes that the densification rates increase as the initial particles sizes decrease and vice versa. This shows that the densification depends directly on the initial compact density which reflects the contacts area between the particles . How
... Show MoreIn this paper, we established a mathematical model of an SI1I2R epidemic disease with saturated incidence and general recovery functions of the first disease I1. Considering the basic reproduction number, we obtained conditions for both disease-free and co-existing cases. The equilibrium points local stability is verified by using the Routh-Hurwitz criterion, while for the global stability, we used a suitable Lyapunov function to analyze the endemic spread of the positive equilibrium point. Moreover, we carried out the local bifurcation around both equilibrium points (disease-free and co-existing), where we obtained that the disease-free equilibrium point undergoes a transcritical bifurcation. We conduct numerical simulations that suppo
... Show MoreThe results of theoretical and experimental investigations carried out to study the effect of load and relative sliding speed on the abrasive wear behavior in drilling bit teeth surfaces of an insert tungsten carbide bit have been presented. Experimentally, an apparatus for abrasive wear tests conducted on the modified ASTM-G65 was modified and fabricated to facilitate loading and measurement of wear rate for the sand/ steel wheel abrasion test, which involves two cases of contact; first is at dry sand and second is under wet condition. These tests have been carried under varied operating parameters of normal load and sliding speed. A theoretical model based upon the Archard equation has been developed for predicting wear simulation by u
... Show MoreThe Iranian people from the people who entered Islam in the early Islamic conquest, and they are like the rest of the Islamic peoples harbor love and respect for the Ahl al-Bayt (as) and Imams (peace be upon them), was reflected in the historical and Adbyatem prose and poetic writings
Approximately 15% of all couples all over the world suffer from difficulty conceiving their first child. The word "infertility" is used to describe this problem.
When a couple had regular, unprotected sexual intercourse for a year or longer, it indicates that they have been unsuccessful in their efforts to conceive.
The current investigation aims to find out if there is a relationship between PROTAMIN-1(PRM-1) and INTERLEUKINE-12 (IL-12) gene expressions and their effect on the development of infertility. The current investigation comprised 100 teratozoospermia patients and 100 healthy fertile controls who had their semen examined. Samples were given by Al-Nahrain University's Biotech
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