Evaluation Study of Free Spanning Subjected to Hydrodynamic Loads

 تحدث ظاهرة الفضاء المعلق الغير مسنود بصورة عامة عند مد خطوط الأنابيب على ارض متموجة التي تحدث نتيجة لعوامل التعرية للتربة المحيطة بالأنبوب المكشوف الغير مدفون. لذلك من الضروري دراسة حركة المائع حول خط الانبوب المتولدة وحساب مقدار الهطول والاجهادات المتولدة لهكذا نوع من خطوط الأنابيب الغائصة تحت الماء. في هذا البحث تم تسليط الجهد لتخمين وتحري الاجهادات خلال جزء الأنبوب المعلق الغير مستند على تربة قاع البحر ودراسة تأثير خصائص هذه التربة عند نقاط الاستناد على سلوك خطوط الأنابيب. تم عمل نموذج لفضاء الأنبوب المعلق باستخدام برنامج (ANSYS) الذي يعتمد على نظرية العناصر المحددة وكذلك تم إدخال تأثير حركة الموجة والتيار لغرض وصف البيئة المحيطة بالأنبوب بدقة اكبر. بينت النتائج المستحصلة من الدراسة ان شدة الاجهادات تتزايد كلما اقتربنا إلى مركز الفضاء الحر.Suspended spans generally occur in subsea pipelines as a result of the irregularity of seabed. Additionally the suspended spans mostly result from the scouring phenomena around the installed non-buried pipeline. So as to discuss the hydrodynamic surrounding the pipeline and determining the significant deflections and associated stresses of the subsea pipeline in unsupported part, therefore, it’s very necessary to study the hydrodynamic surrounding the pipeline in detail. A two main aims have been done in this study, first assess the stresses at free span section and the second one was the effect of soil characteristics in contact area between pipeline and the seabed soil. A combined model of stresses/lateral displacement has been made. An ANSIS model has been built on the offshore pipelines as a consequence of the combined hydrodynamic loads such as wave/current effects. The calculations have been computed by using the finite element method for the free span to describe the surrounding environment in more accuracy. The pipeline stresses intensity increases with closing to free span center. This is attributed to the fact that UY and UZ have more maximum values at these region

The Use of Code Switching: A Case of Iraqi Students in University of Karabuk

Code switching (CS) is considered as a widespread multifunctional phenomenon in bilinguals’ speech both formally and informally. CS is common among Arabic speakers because they usually use it when switching from English to Arabic in their utterances. Iraqi students are enlisted within this rule because they usually use English-Arabic CS. The current study aims at exploring the types of code-switching used in students’ daily life conversations in University of Karabuk and in dormitory setting and the reasons for using this code switching. These conversations are recorded and transcribed into written texts. Then, they are analysed by using Appel and Muysken’s (2005) classification of code-switching. Basing on the data input, the findings showed that the intra-sentential type is the most frequent type used in these conversations. Also, the findings showed that the reasons for code-switching were primarily either to convey a message or to express gratitude. These results were congruent with Poplack’s (1980) hypothesis. The study contributes noticeably to the knowledge body of literature as highlighting the use of code switching in the Turkish city of Karabuk

Influence of La3+ on structural, magnetic, dielectric, electrical and modulus spectroscopic characteristics of single phase CoFe2−xLaxO4 nanoparticles

In this work, we have studied the influence of La3+ substitution on structural, magnetic, dielectric, electrical and modulus spectroscopic characteristics of cobalt ferrite nanoparticles synthesized by starch-assisted sol–gel combustion method. The powder X-ray diffraction analysis confirms the formation of single-phase CoFe2−xLaxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) spinel ferrite nanoparticles. Raman spectroscopy study also reveals the formation of single phase spinel ferrite crystal structure. The morphological feature of synthesized ferrite nanoparticle was observed by scanning electron microscopy that demonstrate formation of spherical nanoparticles with grain size 10–50 nm. The presence of constituent’s, i.e., Co, Fe and La were authenticated by energy dispersive X-ray analysis. The magnetic parameters are measured by employing vibrating sample magnetometer. The saturation magnetization decreases with La3+ substitution, whereas coercivity shows anomalous behaviour. Cation redistribution in spinel ferrite nanoparticles are confirmed by X-ray photoelectron spectroscopy. The variation of dielectric constant (ϵ′, ϵʺ), loss tangent (tanδ), ac conductivity (σ), electric modulus (M′, Mʺ) and impedance (Z′, Zʺ) as a function of La3+ ion concentration and frequency has been investigated. The dielectric constant and ac conductivity increases with increase of La3+ substitution, whereas dielectric loss tangent exhibits anomalous behaviour. The modulus spectra reveal two semicircles associated with grain and grain boundary effects. The cole–cole plots in modulus formalism show that the electrical characteristics contribute from both the grains and grain boundaries. Modulus spectra suggest that the distribution of relaxation times and conduction mechanism are influenced by La3+ ion substitution in cobalt ferrite nanoparticles. © 2017, Springer Science+Business Media New York.Ministry of Education, Youth and Sports of the Czech Republic-Program NPU I [LO1504