Study of the Microstructure of the Gas Turbine Internal Blade

High Pressure Turbine (HPT) first stage blade is the most important rotational components of aero-engine. It operatesat high temperature and under conditions of extreme environmental attack such as oxidation and corrosion, isespecially subjected to degradation by oxidation, corrosion and wear. Due to the elevated temperature been introduced on the turbine blades, they faced several failure such as thermal stress failure and creep. This failure is very common and always occurred on this life limiting component of gas turbine. Further study on the microstructure behavior with respect to the temperature along the blade is carried out to predict the cycle life of the blade. The objective of this project is basically to study on the microstructure of Nickel based Superalloy characterization. The study is mainly focusing on the evaluation of the morphology changeof the γ′particles, carbide precipitation and characterization of particle type and size.Then, a complete procedure and testing related with the study of gas turbine blades were performed using relevant equipment and tools.The procedure involves preparing metallographic sample, chemical analysis and analyzing the microstructure under FESEM and EDS. Though, the main objective of this project is to create a complete profile of microstructure along the turbine blade. This profile is believed to be very useful in the industry to predict the cycle life of turbine blade. Thorough analysis been done,the microstructure undergoes transformations which likely degrade the mechanical properties of the alloy, including γ’ coarsening, increased carbide precipitation in grain boundaries, andincreasinggrain size with respect to temperature. From the analysis, we can predict the temperature profile alongside the blade, which is increase from lower part to upper part. Therefore, the operating temperature of gas turbine need to be maintain so that the microstructure of blade is not affected and as well reduce the lifespan of turbine blade

SELECTION OF NEW PROMISING SEEDLESS MANDARINS TRIPLOID HYBRIDS FROM CROSSES BETWEEN MONOEMBRYONIC DIPLOID FEMALE AND DIPLOID MALE PARENTS

Morocco is one of the major exporters of small citrus fruits, such as mandarin and Clementine. Seedlessness is a major criterion for this horticultural group. The present study focused on the selection of the best triploid mandarin hybrids (2n=3x=27) characterized by seedless fruits. A series of crosses between ‘Sidi Aissa’ clementine (female parent) and seven mandarin varieties (‘Lee’, ‘Wilking’, ‘Osceola’, ‘Carvalhal’, ‘Satsuma Frost’, ‘Satsuma Owari’ and ‘Chienka’) was performed by the National Institute for Agricultural Research. Forty triploid mandarins were obtained and planted since 2002 in an experimental field at El Menzeh. Varietal evaluation was focusing on fruit quality traits during seven years. Statistical analyzes showed that there is a significant difference for all studied characters and between hybrids. The number of seeds per fruit is the main criterion which differentiates between triploids mandarin’s hybrids and their diploid parent “clementine Sidi Aissa”. The best hybrids selected were: HT11, HT13, HT27, HT43, HT44, and HT49. The best crosses are C1 (‘Sidi Aissa’ × ‘Wilking’) andC2 (‘Sidi Aissa’ בOsceola’). These promising triploid hybrids of mandarin have been multiplied on several rootstock trials and are in the process of quantitative evaluation and multi-site testing

Depth of cure of resin composites: effect of incremental layering versus bulk placement and effect of curing light type

Background: The introduction of resin composite was a revolution in dentistry and it has shown a high level of success as a direct restorative material. Appropriate techniques and light curing units are essential for optimal clinical outcomes. Objective: To assess depth of cure of two bulk-fill composites and one nanofill resin composite, when photopolymerized with two different curing light units (CLU), placed with an incremental layering versus bulk-fill technique. Material and methods: Two Bulk-fill resin composites (Surefil SDR® Flow and Tetric EvoCeram®) and a conventional nanofill (FiltekTM Supreme Ultra) were used to prepare 90 cylindrical specimens. Specimens (n=5/group) were made using two placement techniques (incremental and bulk-fill). Each specimen was polymerized using one of two LCUs (Valo® LED [standard power or extra- power mode] and OptiLux 501® QTH), with irradiation times set according to the manufacturer recommendations. Vickers microhardness was evaluated starting from the top to the bottom surface of each specimen. Ten measurements were made sequentially (0.4 mm intervals). A three-way ANOVA and Tukey’s post hoc test was used (significance of 0.05) to analyze the DOC data. Results: All resin composite groups cured with LED CLU (extra-power for 3 sec) and placed using a bulk-fill technique showed significant differences (p\u3c0.05) in hardness ratio (DOC analysis). Conclusions: An incremental insertion technique showed a significantly higher DOC for all composite resin groups when compared to bulk insertion. Therefore, it is not recommended to use a bulk-fill technique with conventional composite. Delivering high irradiance(3200 mW/cm2) and exposure time (3 sec) for LED CLU did not exceed the threshold value for bottom to top hardness ratio of 80% at 4 mm as claimed for Bulk-fill composites when using a bulk-fill insertion technique. Tetric EvoCeram Bulk Fill achieved a 3.2-mm DOC when LED CLU standard power was used for 10 seconds using a bulk-fill insertion technique. The best results were achieved with combinations of incremental insertion and use of a QTH curing light with extended curing time (40 sec)

PENGARUH STRATEGI PEMBELAJARAN SODAS (SITUATION, OPTION, DISADVANTAGES, ADVANTAGES, SOLUTION) TERHADAP KEMAMPUAN PENGAMBILAN KEPUTUSAN SISWA SMA MENGENAI KESEHATAN REPRODUKSI

Penelitian ini dilatarbelakangi pentingnya kemampuan pengambilan keputusan sebagai bagian dari keterampilan tingkat tinggi yang perlu dikuasai oleh siswa. Selain itu perlunya siswa mempelajari kesehatan reproduksi yang diterapkan dalam kurikulum sekolah dikarenakan tingginya penderita penyakit reproduksi di kalangan siswa. Tujuan penelitian ini untuk menganalisis strategi pembelajaran SODAS terhadap pengambilan keputusan siswa SMA mengenai kesehatan reproduksi. Metode yang digunakan dalam penelitian ini adalah pre-experiment yang melibatkan 27 siswa kelas XI SMA Pasundan 2 Bandung dengan desain penelitian yang digunakan adalah one group pretest posttest design. Data diambil sebelum dan setelah pembelajaran SODAS terkait kesehatan reproduksi untuk melatih siswa membuat keputusan. Data penelitian dikumpulkan dengan menggunakan soal uraian tes pengambilan keputusan sebanyak 12 soal uraian dan angket penerapan strategi pembelajaran SODAS sebagai data penunjang. Pada temuan penelitian ini terdapat Sig. 2-tailed sebesar 0,00 lebih kecil dari α=0,05 menunjukkan terdapat perberbedaan yang signifikan antara nilai pre-test dan post-test kemampuan pengambilan keputusan siswa. Hasil penelitian menunjukkan terdapat peningkatan kemampuan pengambilan keputusan siswa dengan strategi pembelajaran SODAS didapat dari nilai N-Gain sebesar 0,50 dikategorikan sedang. Pada kemampuan pengambilan keputusan siswa sebelum pembelajaran menunjukkan nilai rata-rata sebesar 55,63 (kategori cukup). Sedangkan setelah pembelajaran nilai rata-rata kemampuan pengambilan keputusan siswa sebesar 77,79 (kategori baik). Adapun indikator kemampuan pengambilan keputusan dengan nilai tertinggi adalah mengidentifikasi masalah sebesar 88,89 (kategori sangat baik), sedangkan indikator dengan nilai terendah adalah mengevaluasi keputusan sebesar 63,49 (kategori baik). Oleh karena itu, disimpulkan penerapan strategi pembelajaran SODAS dapat memfasilitasi dalam meningkatkan kemampuan pengambilan keputusan siswa.----------This research is motivated by the importance of decision-making abilities as part of the high-level skills that students need to master. Besides the need for students to learn reproductive health that is applied in the school curriculum due to the high number of reproductive diseases among students. The purpose of this study was to analyze SODAS learning strategies for high school students' decision making regarding reproductive health. The method used in this study was a pre-experiment involving 27 students of class XI Pasundan 2 Bandung High School with the research design used was one group pretest posttest design. Data is taken before and after SODAS learning related to reproductive health to training students to make decisions. The research data were collected using 12 test questions in the decision-making test description and questionnaire application of the SODAS learning strategy as supporting data. In the findings of this study, there is Sig. 2-tailed by 0.00 smaller than α = 0.05 indicates that there is a significant difference between the pre-test and post-test scores of students' decision-making abilities. The results showed there was an increase in students' decision-making abilities with the SODAS learning strategy obtained from the N-Gain value of 0.50 categorized as moderate. On the ability of students' decision making before learning shows an average value of 55.63 (enough categories). Whereas after learning the average value of students' decision-making abilities is 77.79 (good category). The indicator of decision making ability with the highest value is to identify the problem of 88.89 (very good category), while the indicator with the lowest value is to evaluate the decision of 63.49 (good category). Therefore, it was concluded that the application of the SODAS learning strategy could facilitate the improvement of students' decision making abilities

Activity Hour in Saudi Education; Emphasizing a Culture of Dialogue and Conversation

This paper focuses on the benefits of applying dialogue in the classroom. Research shows that dialogue can be a way of learning and generating knowledge. Monologic dialogue is defined as the transmission of knowledge where teachers have predetermined the outcome and control the learning process by preparing material and facilitating the dialogue session( ). The goal in the future is to reach the level of open dialogue that is called dialogic dialogue where teachers and students learn together and the end knowledge is not predetermined by teachers( ). Research also shows how teaching dialogue helps students to have an open mind toward diverse perspectives, listen, and learn to respectfully disagree( ). By allowing students to dialogue about different subjects, learners develop a deeper understanding of social issues and become better citizens, which builds their character( ). This paper emphasizes the role of teachers in building a strong relationship with their students to enable their successful classroom engagement, which allows the learning experience to occur. Research findings suggest that there is a positive correlation between student-teacher relationships and students’ participation in school (Laet et al., 2016). To achieve the goals of the dialogue, teachers have to plan the discussion well and scaffold instruction to support learning( ). In this paper, the Developing Students Dialogue Skills (DSDS) program is developed to be applied in Saudi high schools. The program is proposed for students as a three-week training program that will take place during the Activity Hour time. After evaluating the effectiveness of the program, a proposal to expand the program will be developed and submitted to the Department of Education for approval. Three-day teacher training programs are suggested as the next step to expand the application of the DSDS program to all district high schools

Survivorship Pensions in the Middle East and North Africa Region : Current Situation, Costs and Options for Reforms.

The purpose of the survivor's pension is to create rights for young and old age dependants. In the case of developed countries, the system deals essentially with the spouse survival. In the case of MENA countries, the survivor’s pensions scheme provides a wider perspective of coverage and is extended to protect children, brothers, sisters, dependant parents and grand-parents according to specific criteria. Two objectives of survivor's pensions can be distinguished. On the one hand, the survivor's pensions aim at providing a minimum of resources when the widow(er) could not acquire any other sources of income. In this case, the widow survivor's pension is provided to the most modest households in order to help them from plunging in extreme poverty. This context prevails widely in MENA countries, where poverty is high and the level of dependancy is also prominent. On the other hand, a second perspective considers the survivor's pensions as a pension right to the widow (er) with the aim of maintaining her/his former standard of living. Developed countries are particularly concerned by this environment. This paper propose an analysis of the impact of pension reforms, particurlarly, of the survirvorship pensions reforms on the individual situations of retirees. The analysis focuses on Moroccan pension system and will consider a representative sample of members of the main schemes in Morocco.Survivorship Pensions; Reforms; MENA countries; Morocco;

Numerical Analysis of Least-Squares Group Finite Element Method for Coupled Burgers' Problem

في هذا البحث ،  قُدمت طريقة المربعات الصغرى للعناصر المحددة المجمعة  لحل مسألة برغرز الثنائية  ذات البعدين.  أستُخدمت صيغة التقطيع الكلي لطريقة المربعات الصغرى للعناصر المحددة المجمعة بتطبيق طريقة اويلر الخلفية لمتغير الزمن ,  التقسيم بمتغير الفضاء طُبق  كعناصرتربيعية  رباعية الزوايا ذات تسع عقد لكل عنصر. تم إثبات الاستمرارية والإهليلجية وشرط الاستقرار وتقدير الخطأ لطريقة المربعات الصغرى للعناصر المحددة المجمعة  ، حيث بينت النتائج  النظرية ان تقدير الخطأ لهذه الطريقة هو ο(h^r) .  تم مقارنة النتائج العددية مع الحل الدقيق والأبحاث الأخرى المتاحة عندما تكون الحالة التي يسيطر عليها الحمل الحراري لتوضيح كفاءة الطريقة المقترحة  حيث تم حلها من خلال التنفيذ في برنامج   ماتلاب 2018.In this paper, a least squares group finite element method for solving coupled Burgers' problem in   2-D is presented. A fully discrete formulation of least squares finite element method is analyzed, the backward-Euler scheme for the time variable is considered, the discretization with respect to space variable is applied as biquadratic quadrangular elements with nine nodes for each element. The continuity, ellipticity, stability condition and error estimate of least squares group finite element method are proved.  The theoretical results  show that the error estimate of this method is . The numerical results are compared with the exact solution and other available literature when the convection-dominated case to illustrate the efficiency of the proposed method that are solved through implementation in MATLAB R2018a