لعبة كرة السلة واحدة من الألعاب الجماعية التي تتميز بقوة وسرعة الأداء في المباريات، وهذا لم يأتي مصادفة وإنما جاء نتيجة لتطور العملية التدريبية من جانب ومن جانب آخر امتلاك اللاعبين لقدرات بدنية لها فاعليتها من الأداء ومنها القوة المميزة بالسرعة، إما أهمية البحث فتكمن في السعي إلى تطوير هذه القدرة ومعرفة تأثيرها في الأداء المهاري لتكون عوناً للمدربين في العملية التدريبية. أما مشكلة البحث فيمكن أن توضع في تساؤل هو هل يتم استخدام تمرينات نوعية متنوعة لتطوير القوة المميزة بالسرعة على وفق العتبة اللاهوائية في الأعداد الخاص لمعرفة تأثيرها في تطوير الأداء المهاري. يهدف البحث إلى إعداد تمرينات على وفق العتبة اللاهوائية لتطوير القوة المميزة بالسرعة، ومن ثم معرفة تأثيرها في تطوير الأداء المهاري الدفاعي ( حركة اللاعب المدافع، والسحب الدفاعي). أما فرض البحث فيشير إلى أنّ هناك فروقاً ذات دلالة إحصائية بين الاختبارات القبلية والبعدية في متغيرات البحث. أجري البحث على لاعبي الشباب لنادي الأعظمية الرياضي بعدد (12) لاعب وبنسبة (16.66%)، إذ تم إجراء الاختبارات التالية (القوة المميزة بالسرعة للذراعين والرجلين، حركة اللاعب المدافع، السحب الدفاعي) وأستمر البحث للفترة من (24/8/2013 ولغاية 26/10/2013)، فضلاً عن الوسائل الإحصائية المناسبة. استنتج الباحثون إن التمرينات المستخدمة في البحث على وفق العتبة اللاهوائية أدت إلى تطوير القوة المميزة بالسرعة للذراعين والرجلين ومن ثم أحدثت تطوراً في متغيرات البحث المهارية. يوصي الباحثون بضرورة استخدام التمرينات البدنية اللاهوائية في التدريب كونها فعّالة في تطوير القوة المميزة بالسرعة والتي بدورها لها تأثيرها في تطوير مهارتي (حركة اللاعب المدافع، والسحب الدفاعي)، وذلك من خلال تخصيص الوقت الكافي لها في الوحدات التدريبية.
The influence of sensing element length of no-core fiber strain sensor has been studied and experimentally demonstrated, four different lengths of 125 μm diameter no-core fiber is fused between two standard single-mode fibers and bi-directionally strained, the highest obtained sensitivity was around 16.37 pm με -1 which was exhibited in the shortest no-core fiber segment, to the best of our knowledge this is the first study of the influence of no-core fiber strain sensors length on sensor sensitivity. The proposed sensor can be used in many opto-mechanical applications such as, structural health monitoring, aerospace vehicles and airplane components monitoring.
Random laser gain media is synthesized with different types of dye at the same concentration (1×10-3 M) as an active material and silicon dioxide NPs (silica SiO2) as scatter centers through the Sol-Gel technique. The prepared samples are tested with UV–Vis spectroscopy, Fluorescence Spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive X-ray Diffraction (EDX). The end result demonstrates that doped dyes with silica nanoparticles at a concentration of 0.0016 mol/ml have lower absorbance and higher fluorescence spectra than pure dyes. FESEM scans revealed that the morphology of nanocrystalline silica is clusters of nano-sized spherical particles in the range (25-67) nm. It is con
... Show MoreNanoparticles of copper sulfide have been prepared by simple reaction between using copper nitrate with different concentrations ratio 0.1, 0.3, and 0.5 mM, thiourea by a simple chemical route. The prepared Nano powders have been deposited onto glass substrates by casting method at 60°C. The structure of the product Nano- films has been studied by x-ray diffraction, where the patterns showed that all the samples have a hexagonal structure of covellite copper sulfide with the average crystalline sizes 14.07- 16.51 nm. The morphology has been examined by atomic force microscopy, and field emission scan electron microscopy. The AFM images showed particles with almost spherical and rod shapes with average diameter sizes of 49.11- 90.64 nm.
... Show MoreThe research aims to study the effect of adding (Li2O) to an alkaline glaze containing (K2O, Na2O). Although all the alkaline oxides have common properties, each oxide has something that distinguishes it. The molecular weight of (Li2O) is two times less than that of (Na2O) and three times that of (K2O). Therefore, it is added in small proportions. In addition, it is a very strong flux, so it is not used alone, but rather replaces a part of other alkaline oxides. It was added to an alkali glass that matured at a temperature of 980CO in proportions (2.0,1.4,1.2,0.8,0.4%) instead of (Na2O), using lithium carbonate (Li2CO3) as an oxide source. The glazes mixtures were applied to a white pottery body, and the samples were fired and cooled acc
... Show MoreHeavy metal ion removal from industrial wastewater treatment systems is still difficult because it contains organic contaminants. In this study, functional composite hydrogels with photo Fenton reaction activity were used to decompose organic contaminants. Fe3O4 Nanoparticle, chitosan (CS), and other materials make up the hydrogel. There are different factors that affected Photo-Fenton activity including (pH, H2O2 conc., temp., and exposure period). Atomic force microscopy was used to examine the morphology of the composite and its average diameter (AFM). After 60 minutes of exposure to UV radiation, CS/ Fe3O4 hydrogel composite had degraded methylene blue (M.B.)
... Show MoreA solar updraft tower power plant (solar tower) is a solar thermal power plant that utilizes a combination of solar
air collector and central updraft tube to generate an induced convective flow which drives pressure staged turbines to generate electricity.
This paper presents practical results of a prototype of a solar chimney with thermal mass, where the glass surface is replaced by transparence plastic cover. The study focused on chimney's basements kind effect on collected air temperatures. Three basements were used: concrete, black concrete and black pebbles basements. The study was conducted in Baghdad from August to November 2009.
The results show that the best chimney efficiency attaine
... Show MoreMany studies dealt with the consequences of SARS CoV-2 (which cause COVID-19 infection) on the nervous system especially sensory nerves where the virus causes loss of taste and smell as it’s known, and may affect auditory nerves and be the expected cause of some hearing problems. A case-control analytic study was performed on a connivance sample of society of university students from a medical faculty. Each participant filled out a questionnaire contains demographic data and general, auditory and respiratory health condition, in addition to vaccination status. In the other side, the audio- examinations were performed on the study sample including Pure Tone Audiometry (PTA) and tympanometry. Two statistical methods; chi-square and t
... Show MoreThe Isolated Combustion and Diluted Expansion (ICADE) internal combustion engine cycle combines the advantages of constant volume combustion of the Otto cycle with the high compression ratio of the Diesel cycle. This work studies the effect of isolated air mass (charge stratification) on the efficiency of the cycle; the analysis shows that the decrease of isolated air mass will increase the efficiency of the cycle and the large dilution air mass will quench all NOx forming reactions and reduce unburned hydrocarbons. Furthermore, the effect of Fuel / Air ratio on the efficiency shows that the increase of Fuel / Air ratio will increase efficiency of the cycle.
The fluctuations in oil prices in world markets affect the general budget and the trade balance of the rent countries, because oil is a strategic commodity affected by economic and political factors. The fluctuations in oil prices affect the public budgets of the rent countries through the public revenue side of oil revenues. On the other hand, these fluctuations affect the balance of trade through the volume of oil exports, which lead to imbalance of trade surplus or deficit . &nbs
... Show MoreIn this paper, magnesium oxide nanoparticles (MgO NPS) have been prepared and characterized and its concentration effect has been studied on polymers surface (MgO NPS). The results showed that the degradation of poly methyl methacrylate increased when using such metal oxide. The results also showed that the metal oxide increased the degradation of poly methyl methacrylate. X-ray diffraction, scanning electron microscopy, atomic force microscopy were used to study the morphological characteristics and size of nano MgO particles analysis. Films were prepared by mixing the different masses of MgO NPS (0.025, 0.05, 0.1, 0.2 and 0.4) % with a polymer solution ratio (W/V) 7 %. Photo-
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