A theoretical study to design a conformal microstrip antennas was introduced in this work. Conformal microstrip antennas define antennas which can be conformed to a certain shape or to any curved surface. It is used in high-speed trains, aircraft, defense and navigation systems, landing gear and various communications systems, as well as in body wearable. Conformal antennas have some advantages such as a wider-angle coverage compared to flat antennas and low radar cross-sectional (RCS) and they are suitable for using in Radome. The main disadvantage of these antennas is the narrow bandwidth. The FDTD method is extremely useful in simulating complicated structures because it allows for direct integration of Maxwell's equations depending on time. The 1x2 cylindrical circular microstrip antennas array is designed and simulated vertically via Finite Difference Time Domain (FDTD) method where can directive antenna be achieved through antennas array design. Mutual coupling between the antennas in the array and the different separation between them were studied. The circular patch is excited by a probe feed method for several reasons including providing less spurious radiation from the probe current, in addition to the simplicity in theoretical engineering installation and practical manufacturing. It is well known that the values of the coupling are decreased as the distance separation increased. Cylindrical circular microstrip antenna with resonant frequency operating is 3.5GHz for mode, several parameters like return loss, band width, and input impedance are calculated. Also, for isolated coupling, mutual coupling coefficients, directivity gain, for different separations between the centers of the two adjacent circular patches in terms the wave length operating are calculated. Moreover, the electromagnetic band gap EBG structure is used for reducing the mutual coupling created by the surface waves in order to enhance the antenna's performance in an array has become smaller than before. The proposed EBG is a three triangular-shape equal sides metallic structure, utilizing the inter-element spacing in an array. The less value of for the spacing between the two centers of patches is . BW percentage increased to 34.3% and the directivity is enhanced also. Additionally, simulations were done using MATLAB 2017b.
The behavior corrosion inhibition of aluminum alloy (Al6061) in acidic (0.1 M HCl) and saline (3.5% NaCl) solutions was investigated in the absence and the presence of expired diclofenac sodium drug (DSD) as a corrosion inhibitor. The influence of temperature and was studied using electrochemical techniques. In addition, scanning electron microscopy (SEM) was used to study the surface morphology. The results showed that DSD acted as a powerful inhibitor in acidic solutions, while a moderate influence was observed with saline one. Maximum inhibition efficiency was 99.99 and 83.32% in acidic and saline solutions at 150 ppm of DSD, respectively. Corrosion current density that obtained using electrochemical technique was increased with temperat
... Show MoreABSTRACT Background: Viral hepatitis places a heavy burden on the health care. Large number of patient with bleeding disorders has chronic hepatitis C infection, while few are chronic carriers of hepatitis B virus. Aims of study: evaluate the prevalence of HBV, HCV infection among patient with Von Willebrand disease and to find factors that associated with the chance of getting the infection.
The main target of this paper is to determine the optimum time for preventive maintenance on machines. Tow methods has been implemented estimating the optimum time duration for preventive maintenance . the first techniques use scheduling depending on data concerning the machine maintenance cost and halted cost from the production reach to the optimum time for maintenance which reflect the minimum cost. Where as the second techniques depends on reability function to estimate the optimum duration time which reflect the minimum cost. The tow techniques above by which we count on in fixing the preventive maintenance both give same result . we also prove that the scheduling method best than the reability function .
تهدف هذه الدراسة إلى محاولة التعرف على اثر كل من عرض النقود وسعر الصرف على معدل التضخم في الاقتصاد الليبي خلال الفترة 1990-2008. ولتحقيق ذلك فقد تم اختيار الرقم القياسي لأسعار المستهلك ليمثل معدل التضخم، وعرض النقود بالمفهوم الواسع ممثلا لعرض النقود، وسعر صرف الدينار الليبي مقابل الدولار الأمريكي ممثلا لسعر الصرف وقد أخضعت المتغيرات لاختبار السكون والذي تشير نتائجه إلى أن التضخم وعرض النقود وسعر الصرف
... Show MoreThe research explores the shapes preferred by children and the extent to which it can be utilized on the experimental kindergarten at the Woman’s School of Education. To achieve the goal, the researcher has displayed pictures that have been chosen from within the research boundaries which represent four categories: Geometrical shapes which included (squares, rectangles, triangles, and circles), agricultural shapes which included (apples, oranges, bananas, and grapes), motion pictures shapes (cartoon characters) which included (Jerry the mouse, Twitty the bird, Bugs Bunny the rabbit, and Winnie the pooh), and animal shapes which included (dogs, fishes, frogs, and horses) to the sample children of (60) child (boys and girls) that
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تتميز هذه الورقة بتناولها موضوعاً يخشى الكثيرون الخوض فيه للملابسات الدائرة حوله، وهو اصحاب المصالح كموضوع مهم في الفكر الستراتيجي. فخاضت في مفاهيمه العامة وتصنيفاته ومنظوراته، ووجدت في مفهومه بأنهم اولئك الذين يمكن تمثيلهم بالمجاميع او الوحدات المستقلة التي ترتبط بمنظمة الاعمال عبر شبكة علاقات مؤثرة مختلفة الابعاد والاتجاهات، واذا ما حدث أي خلل في توازن هذه العلاقات، قد ت
... Show MoreThis study aims to find out the impact of activities office provided to kindergarten children in the development of creativity in linguistic performance goal of capabilities (fluency, flexibility and originality) through the application of the test configuration Algheih Children Riyadh, which consists of (70) Single to measure the skills of language arts four a listening and speaking and a willingness to read and prepare for writing, was applied (30) Single of language arts, listening and speaking in this research, and was the correlation coefficient for the hearing (0.78) and for speaking was (0.61) has been extracted stability of the scale using the equation Alvakronbach the value of (0.73).
The proper
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