The problem of the high peak to average ratio (PAPR) in OFDM signals is investigated with a brief presentation of the various methods used to reduce the PAPR with special attention to the clipping method. An alternative approach of clipping is presented, where the clipping is performed right after the IFFT stage unlike the conventional clipping that is performed in the power amplifier stage, which causes undesirable out of signal band spectral growth. In the proposed method, there is clipping of samples not clipping of wave, therefore, the spectral distortion is avoided. Coding is required to correct the errors introduced by the clipping and the overall system is tested for two types of modulations, the QPSK as a constant amplitude modulation and 16QAM as a varying amplitude modulation.
Rutba area is located in Al-Anbar Governorate - West of Iraq. Hydrogeological investigation calculation of Mulussa aquifer between Rutba and Dhabaa is carried out. The groundwater moves in directions of (NE, E and SE) influenced by depletion process in the amount of hydraulic gradient ranged between (0.0000416 - 0.008036). The groundwater flux (V) and groundwater pore velocity (U) are reached (0.00451) m/day and (25.02) m/day, respectively. Mulussa aquifer is carbonate beds, where represents confined aquifer conditions. The values of transmissivity, permeability and storage coefficient are ranged between (0.507 – 250) m2/day, (0.00547 - 3.05) m/day and (9.65 x 10-5 - 2.64 x 10-4
... Show MoreThe present work involved two steps: the first step include Mannich reaction was carried out on 2- mercaptobenzimidazole using formaldehyde and different secondary amine or amide to gives the compounds(2-16). The secnd step include preparation of (Ethylbenzimidazoly-2-mercaptoacetate)(17) from the reaction of 2- mercaptobenzimidazole with ethylchloroacetate than prepared hydrazide derivative[18]from reaction of compound(17) with hydrazinehydrate. Followed Preparation of shiff bases(19-24) and there reaction with mercaptoacetic acid to give a new compounds containing thiazolidinderivetives(25-30).Structure confirmation of all prepared compound were proved using FTIR and element analysis (C.H.N.S) and mesurmentedmelting poi
... Show MoreBackground: Seasonal variation and gender preponderance have not been adequately studied in Guillain-Barre syndrome (GBS).
Objective: This study aims to evaluate the seasonal variation and sex preponderance in children with Guillian Barré Syndrome.
Patients and methods: A cross sectional study was carried out by reviewing wards’ registry of all cases with Guillian Barré Syndrome admitted to Children Welfare Teaching Hospital during a 10-year period (1999 - 2008). Age, sex, seasonal distribution, residence and outcome were analysed.
Results: Guillian Barré Syndrome was diagnosed in 217 (126 boys, 91 girls) patients and the annual hospital rate of admission was 22.9 /100000 children. There was increase annual incidence from 1
Oscillation criteria are obtained for all solutions of the first-order linear delay differential equations with positive and negative coefficients where we established some sufficient conditions so that every solution of (1.1) oscillate. This paper generalized the results in [11]. Some examples are considered to illustrate our main results.
In this research some new nucleoside analogues were synthesized. Starting from α-D- glucose which was protected to glucose penta acetat α-D- glucose pyronside (1). Which was converted to active form 1-bromo protected sugar (2) as a sugar moiety. The base moiety 2-substituted imidazoline (3,4) was prepared from condensation of ethylene diamine with two kind of aromatic aldehydes, which were subjected to amino alkylation via Mannich reaction forming new nucleaobase derivatives (5-10). Condensation of nucleobase with bromo sugar through nucleophilic substitution of anomeric carbon with nitrogen forming new protected nucleoside analogues (11-16). De blocking of these nucleoside analogues with sodium methoxide in methanol afforded our targe
... Show MoreWhen the depth of stressed soil is rather small, Plate Load Test (PLT) becomes the most efficient test to estimate the soil properties for design purposes. Among these properties, modulus of subgrade reaction is the most important one that usually employed in roads and concrete pavement design. Two methods are available to perform PLT: static and dynamic methods. Static PLT is usually adopted due to its simplicity and time saving to be performs in comparison with cyclic (dynamic) method. The two methods are described in ASTM standard.
In this paper the effect of the test method used in PLT in estimation of some mechanical soil properties was distinguished via a series of both test methods applied in a same site. The comparison of
... Show MoreBackground: Body image is one of the most important psychological factors that affects adolescents’ personality and behavior. Body image can be defined as the person’s perceptions, thoughts, and feelings about his or her body.
Objectives: to identify the prevalence of body image concerns among secondary school students and its relation to different factors.
Subjects and methods: A cross-sectional study conducted in which 796 secondary school students participated and body shape concerns was investigated using the body shape questionnaire (BSQ-34).
Results: The prevalence of moderate/marked concern was (21.6%). Moderate/ marked body shape concern was significantly associated
... Show MoreEriobotrya japonica Lindl., named as loquat, is a subtropical fruit tree of the family Rosaceae which is well known medical plant originated in Japan and China. Loquat portions, like leaves, peels and fruits have been shown to possess various health usefulnesses. In Chinese classical medicine, it is vastly utilized in many illnesses, like gastroenteric disorders, diabetes mellitus, pulmonary inflammatory diseases and chronic bronchitis. Loquat plant contain many active constituents, such as flavonoids, carotenoids, vitamins, polyphenolic compounds, other that have many biological effects like anti-tumor, anti-diabetic, anti-inflammatory, anti-mutagenic, antioxidant, antiviral, antitussive, hepatoprotective and hypoli
... Show MoreThere is no doubt that optical fiber technology is one of the most important stages of the communications revolution at all and it is of utmost importance in our daily life. In this work, five fibers with core radii 2.5, 4.5 and 6.5–8.5 μm were designed. The properties of all guided modes have been calculated at a wavelength of 1550 nm by using RP Fiber Calculator. A single-mode fiber is obtained when the core radius approaches the wavelength. As the core radius is increased, the fiber becomes a multimode. The percentage power in the core increases with increasing core radius. The modes profiles were illustrated and compared with the modern references.
The aim of the research was to prepare the fields and items for safe environment scale form professional basketball players and coaches’ point of view. The researchers used the descriptive method on professional athletes of players and coaches from (11) clubs; for the pilot study (21) athletes were selected and for the building sample (103) athletes, and standardization sample (101) athletes from the participants in the Iraqi league (2018-2019). The scale of the safe environment was concluded with (6) fields and (52) items. The researchers came up with the safe environment scale from the point of view of professional basketball players and coaches. Finally the researchers recommended paying attention to providing safe environment for athl
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