Thracian Hera

DergiPark: 326510trakyasobedThe Goddess Hera was protector of women in the old Greek religion. In this study, used by the old Greek, Latin and the modern sources, and the some votive reliefs found in Thracian, especially in Bulgaria, dated 3 rd century BC, we aim to you give some knowledge about the symbols of Thracian Hera and later, because of her relation with the God Saturnus, we give some information about her agricultural features in this region, that were refered little in old Greek mithologiaBu çalışmada, Eski Yunanca, Latince ve modern yazılı kaynaklardan yararlanarak, arkeolojik çalışmalar sonucu Trakya bölgesinde (özellikle Bulgaristan tarafında) bulunan ve M.Ö. III. yüzyıla tarihlendirilen bazı kabartmalardan yola çıkarak, Eski Yunan dininde kadınların koruyucusu olan tanrıça Hera’nın taşıdığı simgeler ve buna bağlı olarak Trakya Herası’nın, tanrı Saturnus’la olan bağı nedeniyle Yunan mitolojisinde az işlenen, bir özelliği olan tarımla ilgili yanı üzerinde durulmaktadı

Modelling Of Post-Injection Strategies Of Ethanol And Experimental Analysis Of The Use Of Ethanol In The Form Of Dual Fuel And Emulsion In Diesel Engine

In this research, as the first stage, the effects of the ethanol on engine performance and emissions under the fumigation and emulsion method were experimentally investigated under part load and various engine speed conditions. Diesel-ethanol blend containing 5% ethanol by volume was used as the mixture fuel. In the fumigation method, ethanol was used at the same rate and 99.9% purity as the emulsion method. As the second stage, the effects of ethanol post injection on engine performance and pollutant emissions were investigated in the experimental engine modeled in AVL Boost simulation program and compared with the experimental results. Simulation post injection tests were performed separately after the main injection at 3° CA (P1) and 7° CA (P2). In the experimental studies, NOx emission decreased with the emulsion method (E5) at low and high engine speeds. In post injection strategies, NOx emission in general increased due to improved combustion and increased in-cylinder temperature with P1 (first post injection) and P2 (second post injection) strategies. Soot emission decreased significantly with E5. This improvement in soot emissions was approximately 87% in post injection strategies. © 2021 Society of Thermal Engineers of Serbia Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This is an open access article distributed under the CC BY-NC-ND 4.0 terms and condition

Yer radar yöntemi ile Kuzey anadolu fayının Balıkesir yöresinden geçen kesiminin belirlenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Ülkemiz birçok jeolojik ve tektonik yapının bulunduğu bir coğrafyadadır. Depremler hayatımızın gerçekleri arasındadır. Yaşadığımız alanların emniyetini sağlayabilmek için öncelikle yeraltının iyi bir şekilde bilinmesi gerekmektedir. Bu bağlamda yeraltını en doğru bir şekilde görüntüleyecek sistemler ve buna bağlı yapılacak yorumlar büyük önem kazanmaktadır. Konuyla ilgili birçok yöntem olup, yer radarı yöntemi; son yıllarda elektronik ve bilgisayar teknolojilerinde olan gelişmelere bağlı olarak birçok sahada kullanılan yöntemlerden biri olmuştur.Bilindiği üzere Balıkesir yöresi Türkiye aktif tektonizmasında birçok sistemin bir arada çalıştığı bir bölgedir. Ege horst graben yapısının etkisi ve Kuzey Anadolu Fay Zonunun bir kısmının da bu bölgeden geçmesi bölgenin tektonik aktivite yönünden zengin olmasına sebep olmaktadır.Çalışmada yer radarı yöntemi kullanılarak ana fayı kesen kılcal fay yapılarından bir bölümü kesilmiş ve fay yapılarının belirlenmesi amaçlanmıştır. Yer radarı kayıtlarında yapılan düzenlemeler ve veri işlemlerle kayıtlar okunur hale getirilmiş bulunan faylar arazide gözlenmiş faylarla karşılaştırılmıştır.Turkey is on a geography that has many geological and tectonic structures. Earthquakes are among the realities of our lives. To ensure the safety of our living space, first you need to know underground well. In this context, the most accurate way of displaying the underground systems and their interpretations are gaining importance.There are many methods for displaying the underground systems and in association with the developments of the electric and computer technologies in recent years, the GPR method has become a method to be used in many areas.As known, Balikesir district, north western Turkey, is a region of active tectonics with many tectonic system in work. Affectof the Graben-Horst structure of the Aegean region and crossing of the part of the North Anatolian Fault within the region have caused high tectonic activity.In the study the small faults that transcutting the main fault are displayed and interpreted for mapping their structural properties through utilizing GPR method. The initial data has been arranged and processed before the analysis in order to make them readable and interpretable. Finally, the interpreted faults are compared to the observed faults

The Dardanos in the Old Greek and Roman Epos

DergiPark: 326408trakyasobedThis study aims at introducing the Dardanos basis by the Greek-Roman epos and the mythology. The name of Dardanelia, old name of Çanakkale in Turkey, has originated from the name of Dardanos who was the founder ancestry of Troia too. In this way, the importance given to the knowledge can be seen better what kind of social and spiritual values were appeared in the date of establishment of a city, especially of family tree, in the old age, by means of the poetic memories who were as historians’ duty at these times, the writing was not invented.. The reasons that direct us to this subject are those; one is that we don’t have any collected study about the family tree of Dardanos and Troia in Turkish. The other is that epos and the mythology are not only merely invented stories, but it is also necessary to consider the some of them as impressions passing from generation to generation that was experienced in the past. If these mythologies were fictitious, we didn’t have any basis on the art, traditions, religion and especially on the ancestry. In this view, Dardanos is good example for the old times.Bu çalışma, Yunan-Roma destan geleneğine, ayrıca söylencelere dayalı olarak, Çanakkale ilimizin eski adı olan Dardania isminin kaynaklandığı ve Troia’nın kurucu atası olan Dardanos’la ilgili bilgileri içermektedir. Böylece, eskiçağda, yazının olmadığı dönemlerde adeta birer tarihçi görevini gören ozanların sorumluluğu, onların belleği sayesinde, soyağacına verilen önem, ayrıca Dardanos’un kentin kuruluş tarihinde taşıdığı manevi değer ve bunun mitoslarla zenginleştirilmesi daha iyi görülecektir. Bizi bu konuya yönelten nedenlerden biri, Dardanos ve Troia’nın soy bilgisiyle ilgili derleyici bir çalışmanın elimizde olmaması; bir diğeri ise destan ve “söylencelerin” sadece “uydurulmuş hikâyeler” değil, bazılarının, dini, kültürel ve gelenekler üzerine kuşaktan kuşağa aktarılan, yazısız zamana da ait önemli olayların izleri olduğunun anlaşılmasıdır. Eğer bu mitoslar uydurma olsaydı, gelişen zaman içinde sanat, hatta gelenek ve önemlisi din ve “ata” anlayışımız da temelsiz kalırdı. Bu açıdan da Dardanos, eskiçağ için iyi bir örneği oluşturmaktadır

Experimental analysis of the global energy balance in a DI diesel engine

The increasingly stringent internal combustion engines (ICE) emissions regulations, has led to the extended use of after-treatment systems, giving progressively more importance to the engine efficiency optimization. In this context, the experimental methodologies to perform and analyse the energy balance show as a key issue to evaluate the potential of different engine strategies aimed at the consumption optimization and the improvement paths identification. This works deals with the complete description of an experimental energy balance tool, including the comprehensive description of the specific designed experimental installation used to the determination of each energy term involved in the energy balance. After the tool description, a study of the energy balance in the engine map of a DI Diesel engine was carried out, with the objective of determining the engine speed and load influence on each energy term. A subsequent parametric study varying the coolant temperature, the intake air temperature and the start of the injection (SOI) and their influence in the engine efficiency has been performed. The results shows that the variation of the coolant temperature has an almost negligible effect in terms of efficiency whilst cooling the air yields in an improvement about 1% and advancing the SOI about 1.5%.The support of the Spanish Ministry of Economy and Competitiveness (TRA2013-41348-R) is greatly acknowledged.Payri González, F.; Olmeda González, PC.; Martín Díaz, J.; Carreño, R. (2015). Experimental analysis of the global energy balance in a DI diesel engine. Applied Thermal Engineering. 89:545-557. https://doi.org/10.1016/j.applthermaleng.2015.06.005S5455578

An adapted heat transfer model for engines with tumble motion

In the last years, a growing interest about increasing the engine efficiency has led to the development of new engine technologies. The accurate determination of the heat transfer across the combustion chamber walls is highly relevant to perform a valid thermal balance while evaluating the potential of new engine concepts. Several works dealing with heat transfer correlations that consider the swirl motion are found in the literature; however, there is a lack of works dealing with heat transfer correlations which take into account the effect of the tumble movement. In this work, a new heat transfer model accounting for the tumble motion is presented. A two stroke HSDI Diesel engine with high tumble and no swirl is used to perform the theoretical study, the model development and its final calibration. Initially, a theoretical analysis of the gas movement phenomena is carried out based on CFD results and then, a model is developed and calibrated based on a skip-fire testing technique. Finally, a sensitivity study focused on evaluating the model robustness is performed. The results confirm an average RMSE reduction of 70% with respect to the Woschni model, being this consistent improvement qualitatively evidenced in the instantaneous heat transfer evolutionThe support of the Spanish Ministry of Economy and Competitiveness (TRA2013-41348-R) is greatly acknowledged.Olmeda González, PC.; Martín Díaz, J.; Novella Rosa, R.; Carreño, R. (2015). An adapted heat transfer model for engines with tumble motion. Applied Energy. 158:190-202. https://doi.org/10.1016/j.apenergy.2015.08.051S19020215

Empirical analysis of the relationship between economic growth and tax revenues in OECD countries

Vergi gelirleri devletin en temel finansman kaynaklarından birini oluşturmaktadır. Bundan dolayı vergilerin, ekonominin temel makroekonomik göstergeleri üzerinde önemli etkileri vardır. Ancak vergilerin bu gösterge- ler üzerinde olumlu etkilerinin yanında olumsuz etkileri de bulunabilmektedir. Bu çalışmada, 1990-2014 döne- minde OECD ülkelerinde ekonomik büyüme ile toplam vergiler, dolaylı vergiler ve dolaysız vergiler arasın- daki ilişki panel FMOLS yöntemi ve Dumitrescu-Hurlin (2012) nedensellik testi kullanılarak analiz edilmiştir. Araştırma sonucunda ekonomik büyüme ile vergiler arasında nedensellik ilişkisi bulunmuştur. Panel FMOLS test sonuçlarında ise, ekonomik büyüme ile dolaylı vergiler arasında pozitif, toplam vergiler ile dolaysız vergi- ler arasında ise negatif bir ilişki olduğu sonucuna ulaşılmıştır. Panel genelinde uzun dönemde dolaylı vergiler- deki artış, ekonomik büyümeyi pozitif, toplam vergiler ile dolaysız vergilerdeki artış ise ekonomik büyümeyi negatif bir şekilde etkilemektedir.Tax revenuesare one of the most basic financial resources of the government. For this reason,taxes have impor- tant impacts on basic macroeconomic indicators. But, taxes may have both positive effects as well as negative effects on this basic macroeconomic indicators. In this study, it was analyzied relationship between economic growth, total revenues, indirect taxes anddirect taxes in OECD countries for 1990-2014periodbyusing Panel FMOLS test and Dumitrescu-Hurlin (2012) panel Granger causality test.According to the research results, there is causal relationship between taxes and economic growth. Panel FMOLS test results Show that there is positive relationship between economic grow than dindirect taxes, there is negative relationship between total revenues and direct taxes.According to the panel general empricial findings of study, thein crease in indirect taxes have a positive effect on economic growth, thein crease in total revenues and direct taxes have a negative effect on economic growth

The impact of teaching algebra through mathematical modeling on 6-grade students' academic success and how they correlate mathematics with daily life

Bu araştırmada, matematiksel modelleme ile cebir öğretiminin 6. sınıf öğrencilerinin akademik başarılarına ve matematiği günlük yaşamla ilişkilendirmelerine etkisini incelemek amaçlanmıştır. Araştırmada hem nicel hem de nitel araştırma yöntemleri kullanılmıştır. Araştırmada, ön-test son-test kontrol grubu içeren yarı deneysel desen kullanılmıştır. Çalışmanın örneklemini Rize ili Kalkandere ilçesindeki Atatürk İlköğretim Okulu'nda 2011-2012 öğretim yılında 6. sınıfta öğrenim gören 65 öğrenci oluşturmuştur. Deney grubunda 33, kontrol grubunda ise 32 öğrenci yer almıştır. Dersler üç hafta boyunca deney grupları ile modelleme etkinlikleri ile yürütülürken, kontrol gruplarında ise müfredatın ön gördüğü etkinlikler kullanılmıştır. Araştırmanın verileri Cebir Başarı Testi, Matematik ve Günlük Yaşam Testi, modelleme etkinlikleri ile elde edilen işlem ve rapor kağıtları ve mülakatlarla toplanmıştır. Elde edilen nicel veriler, SPSS programı kullanılarak değerlendirilmiştir. Nicel verilerin analizinde t testleri kullanılmış, nitel veriler betimsel olarak analiz edilmiştir. Araştırma sonucunda elde edilen bulgularda, deney grubundaki öğrencilerin cebir konusundaki akademik başarılarının ve matematiği günlük yaşamla ilişkilendirme düzeylerinin anlamlı olarak daha yüksek olduğu ortaya çıkmıştır. Öğrencilerin modelleme etkinliklerinin uygulanışı sürecinde model oluşturmada zorluklar yaşadıkları tespit edilmiştir. Ancak, aynı konuya yönelik modelleme etkinlikleri uygulandıkça yaşanılan zorlukların azaldığı görülmüştür. Yapılan mülakatlarda ise öğrencilerin matematiksel modelleme etkinlikleri ile işlenen derslere yönelik duygu ve düşüncelerinin son derece olumlu olduğu belirlenmiştir. Ayrıca etkinlikler süresince matematik dersinde başarı düzeyi düşük öğrencilerin de modelleme sürecine etkin bir şekilde katıldıkları gözlemlenmiştir. Modelleme etkinliklerinin kullanıldığı öğretimde öğrenciler, matematik ve günlük yaşam arasındaki ilişkiyi daha iyi fark ettiklerini belirtmişlerdir. Anahtar Kelimeler: Matematiksel Modelleme, Modelleme Etkinlikleri, Cebir ve Öğretimi, Matematik ve Günlük Yaşam İlişkisi. In this study, it is aimed to analyze the impact of teaching algebra through mathematical modeling on 6-grade students' academic success and how they correlate mathematics with daily life. Both qualitative and quantitative research methods were used in this study. Furthermore, semi-experimental research design including pre-test and post-test control groups were also used in the study. Sample group of the study consists of 65 6-grade students studying at Atatürk Primary School, in Kalkandere, Rize in 2011-2012 academic year. Whereas 33 students involve in experimental group, the other 32 students take part in control group. While lessons of experimental group were held through modelling activities, the activities proposed by the curriculum were applied in the lessons of control group during 3 weeks. Findings of the research were collected through Algebra Success Test, Mathematics and Life Test, paper of operation and rapport obtained through modelling activities and interviews. Quantitative data were analyzed through SPSS. While t-test was used in the analysis of quantitative data, qualitative data were descriptively analyzed. In the results of the study, it has been revealed that academic success of the students in experimental group in algebra and their level of correlating mathematics with daily life were significantly high. It has been also confirmed that students had trouble in the process of practicing modelling activities. However, it has been seen that the more modelling activities regarding the same topic were practiced, the less trouble they had. On the other hand, in the interviews conducted, it has been indicated that students have highly positive feelings and views on the lessons held through mathematical modelling activities. In addition, it has been also observed during activities that the students whose success levels in mathematics are quite low also actively involved in the process of modelling. The students have stated that they have better noticed the relationship between mathematics and everyday life in teaching through modelling activities. Keywords: Mathematical modelling, Modeling Activities, Algebra and its teaching, Mathematics and its relationship with daily life

Analysis Of Impact Of Rivers To The Shoreline In The Vicinity Of Sea-river Function By Amathematical Modelling

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1995Thesis (Ph.D.) -- İstanbul Technical University, Institute of Science and Technology, 1995Akarsuların taşıdığı katı maddelerin iri olanları, akarsuyun denize döküldüğü nehir ağzında çökelir. Daha ince olanları dalgaların etkisi ile kıyı boyunca hareket ederken, bir kısmı ise kıyıya dik hareket eder. Akarsulardan gelen bu katı maddelerin uzun vadede kıyılarda bazı değişikliklere sebep olduğu bilinmektedir. Ayrıca bu katı madde hareketleri mevcut deniz yapılarına da oyulma veya yığılmalar dolayısı ile önemli etkilerde bulunur. Bu çalışmada, denize dökülen akarsuların taşıdığı katı maddelerin kıyı çizgisine ve deniz yapılarına etkileri matematik bir modelle incelenecektir. Akarsuyun getirdiği katı madde enkesitte uniform kabul edilerek kıyı boyu katı madde süreklilik denklemine, sabit birim genişlikten geçen katı madde miktarı olan (q) ilave edilmiştir. Bu durumda katı madde süreklilik denklemindeki türevler yerine ileriye doğru sonlu farkları yazılmış, kıyı boyu katı madde debisini tahmin eden bir formül yardımıyla, başlangıç ve sınır şartlan belli olan bir kıyı şeridi için çözüme gidilmiştir. Akarsuyun genişliği 50 m, 100 m ve 125 m alınarak 1000 metrelik bir kıyı şeridinde meydana gelen değişiklikler incelenmiştir. Bu incelemede akarsuyun konumu sabit alınmıyarak, hesap sınırının başında, ortasında ve sonunda olmak kaydıyla yeri değiştirilmiş ve taşıdığı katı madde debisi q=1.10"3 m3/sn/m, q=1.10-4 m3/sn/m, q=1.10-5 m3/sn/m ile q=1.10-6 m3/sn/m şeklinde değiştirilerek akarsuyun kıyıdaki yeri ve debisinin etkisi açısından bir genelleme yapılmaya çalışılmıştır. Mendirek gibi bir deniz yapısının sağından soluna doğru veya solundan sağma doğru bir katı madde geçişi söz konusu değildir. Aynı zamanda kıyı yapısından belli bir mesafe sonra kıyının yapıdan etkilenmediği ve doğal durumunu koruduğu görülür. Bu incelemede mendireğin hemen bitişiği hesap sınırının başlangıcı olarak kabul edilmiş ve başlangıç sınır şartı olarak bu noktada katı madde debisi sıfir alınmıştır. Mendirekten 1000 m ötede kıyının yapıdan etkilenmediği göz önüne alınarak, bu noktadaki katı madde miktarı bir önceki noktaya eşit alınmak suretiyle hesaplar yapılmıştır. Mendireğin hemen yam başında, mendirek yüksekliği rüzgarın esişini engellediği için bu kısımda ölü bir nokta meydana gelmektedir. Dolayısıyla akarsuyun mendireğin hemen yam başmda denize dökülmesi halinde, akarsu tarafindan taşman katı madde kıyı boyunca kısmen taşınmaktadır. Ancak akarsuyun döküldüğü yer, mendirekten uzaklaştıkça mendireğin kıyıya etkisi azalmakta dolayısıyla akarsuyun taşıdığı katı madde kıyı boyunca daha çok taşınmaktadır. Ayrıca çalışmada elde edilen sonuçlar tablo ve grafikler halinde değerlendirilmiştir. Beach is defined as the coast contained choeisionless materials such as sand and gravel. Along some beaches man-made structures such as harbors, seawalls, breakwaters and shore-connected breakwaters are constructed. The beach itself is constantly in motion and slowly changing its configuration. On a natural beach, the longshore sand transport is usually in equilibrium. If, however, the longshore sand transport is interrupted by a coastal structure, sand will deposit on the updrift side of the structure and erosion will occur on the downdrift side. Coastal sediment transport is either perpendicular to the shoreline (onshore-offshore transport) or parallel to it (longshore transport). Onshore- offshore sediment movements produce short-term variations on the beach profiles, while alongshore movements produce long-term variations. Nearshore currents are the main causes for the movement of sediment. Currents are generated by waves, winds, tides and river outflows. The most important current that cause the movement of sand is the one that flows alongshore in the surf zone which is created by waves breaking at an angle to the shore. On some coasts, alongshore currents annually transport thousands of cubic meters of sand, eroding one beach and building another. Alongshore sediment transport is usually sand moved in the beaches under action of waves and currents. The rate Q that is moved parallel to the shoreline, is the longshore transport rate. There are two possible directions of motion. One of them is from right to left and another of them is from left to right. So sediment transport from right to left is indicated by subscript (It), the other motion is indicated by subscript (it). Gross longshore transport rate (Q ) is the sum of parallel sediment transport on the shoreline in a given time period. Similarly, net longshore transport rate (Qn) is difference between Qrt and Q^. These transport rates may be expressed as follows. Qg = Qrt + Qit Qn = Qrt-Qlt The purpose of this study is to analyse relationship between shoreline, longshore sediment transport and effect of a river. It can be divided into six main parts. The brief summary of these parts have been given as follows. In Chapter II, the types of most important models were analysed. And the model of CERC (Coastal Engineering Resource Center) was used in this xin study. As such as, the longshore transport rate (Q) is usually calculated from the CERC formula. It has been given below. Q = K'(H2.Cg)b.Sin2obs !C * (if \6{ys-\)a\r) Where, K : Non dimensions empirical coefficient (of order 0.4) H : Significant wave height Cg : Wave group velocity ot- : Angle of breaking waves to the shoreline y : Ratio of sand density to water density a : Ratio of volume of solids to total volume r : Conversion factor from root mean Square (RMS) to significant wave height, if necessary (equals, 1.416 ) The subscript (b) indicates quantities at wave breaking. The group velocity at breaking is calculated from; Where, V r ) g : Acceleration of gravity Y : Ratio of wave height to water depth at breaking, approximately equal to 0.78 The a. is the angle of the breaking waves to the shoreline. It is equal to the difference between the angle the breaking waves makes with the x-axis and the angle the shoreline makes with the x-axis; abs = ab'a Where, ov : Angle of breaking waves to x-axis \âcj This condition shows as follows, XIV Direction of Significant v Wavers. NS ^bs^s^oreline Figure 1. x - y Axis and the Condition of Shoreline In Chapter HI, Continuity, momentum equations and equations of wave were described. The conservation of the mass of sand is described by the continuity equation. ât D âc In which. y : Shoreline position t : Time Q : Volume rate of longshore sediment transport x : Distance alongshore D : Vertical distance between the top of the bank and the lowest line where material is moved Effect of a river on shoreline is shown below by the continuity equation ây 1 âO - + - = q a D âc * q : Sediment quantity per unit width of river Also some important equations for sinusoidal wave are snown below -a.C.Cosh[k{y+d)} In fact this equation is velocity potential. In which; Where; XV <|) : Velocity potential a : Amplitude of wave C : Celerity of wave or the phase velocity k : The number of wave d : Water depth y : The distance of y-axis a : Circular frequency Also Bernoulli's equation for unsteady flow, expressing the conservation of energy, can be written as; *¥ U2+V2 p at 2 p where; P : Pressure p : Density of the fluid g : Acceleration due to gravity U : Horizontal velocity of a particle V : Vertical velocity of a particle Wave celerity can be written by equation of velocity potential, ms { l ) In Chapter IV, Equations, which were used of in this study, were explained by use of the explicit scheme of finite differences. In a standard explicit scheme, the continuity equation with effect of river is discretized as For an explicit scheme, there is a stringent limitation on the size of the largest possible time step, other variables being held constant. For small breaking wave angles, in the present case this condition is where, ** = 2K'.At(H2.Cg)b D.{Axf XVI Rg was called, as the stability parameter by Kraus and Harikai. This equation is an adequate indicator of stability in most applications, since breaking wave angles are usually small (Hanson and Kraus, 1986). Present equation is solved by initial and boundary conditions. According to the rule for diffusion equations, we need a boundary condition at each boundary on both sides of the reach. There are few possibilities. One of them is sediment transport which is zero or constant at a construction such as a breakwater and shore-connected breakwater. So we can write as Another boundary condition is far away from a construction. It means that x-»oo. So we can write as aQ or dy_ ds. - Const. X=±00 = Const. X=±00 The shoreline evolution can be calculated with continuity equation and CERC formula. This study was continued with Chapter V which contains applications and evaluation. A mathematical model was setup for the problem and a computer program written in FORTRAN 77 to solve the model was used. The results found in this study were presented in diagrams and in tables. Some assumptions were made been make in this research. These are; 1) The width of river were taken as 50 m, 100 m and 125 m. Also the position of river was at the beginning, middle and end of system. 2) Sediment material of river was selected as 1.10, 1.10, 1.10 and 1.10 outflow per unit width (m3/sn/m). 3) Changes of shoreline were analysed after 1, 3 and 6 years in the mathematical model. 4) The flow chart of computer program is given in Chapter V. The names of parameters and variables are; the angle (theta); denoted as Z, and the empirical coefficient K; denoted as Kl in the computer program. Also the grid XVII spacing is DX (in meters) and the time step is DT (in hours), the wave period is denoted by T (seconds), NTIMES specifies the number of time steps and IT1 and IT2 denote time steps, DENOM is value of physical quantities in the denominator of the CERC's equation, evaluated for quartz sand. 5) It has been assumed that waves coming from NNW, N and NE winds transport sediment material along the shoreline. 6) Strip, 1000 m, was taken into the consideration for computational boundary on the shore and discretized 40 elements. 7) CERC formula was employed for the sediment material computation. The results of the experiments and mathematical model have been summarised in Chapter VI. Finally, the results of the computations were compared with laboratory experiments and natural conditions. 450m Figure 2. Changes in Shoreline at Laboratory -Model (NE, H=2.8 m, 1=6 sec, after 2 hours) A pool having length of 32 m, width of 19.1 m and height of 0.7 m was constructed in the Hydraulics Laboratory of İTÜ. The model of Efirli-Ordu Harbor was built by using of scale of 1/150 in the pool. In this model, XVIII polstryrene, which is equivalent to sand dimension, was used as the sediment material. Changes in the model occurred for two hours are shown in Figure 2 for the wave height of 2.8 m and the wave period of 6 sec and the results observed is presented in Figure 3. Figure 3. Changes in Shoreline According to the Natural Condition The main results of this research can be summarised as follows: 1) Because the sediment transported by the river is relatively less, the main cause of deposition on the shoreline is waves travelling in direction of NE 2) Since sediment transport does not exist across the groin, initial boundary at this point will be taken a zero. So, an eroding process will take place just after groin. 3) Because of height of groin NNW and N winds can not cause any changes on the surface of sea at the just after the eastern side of groin, this region is called as dead zone. Hence sediment transport does not exist in this zone. 4) As moving away from groin, the effect of groin decreases along the shoreline as shown in Figure 4. It will be observed that if amount of deposition is 100 % at the beginning of boundary, 37.5 % at the middle of computation boundary and 33 % at the end of computation boundary. 5) New position can be occurred by changing of the boundary conditions. Hence these conditions can be taken account into future studies.DoktoraPh.D

Experimental analysis of the performance coefficients of the butterfly valves

ÖZETKELEBEK VANALARDA PERFORMANS KATSAYILARININ DENEYSEL OLARAK İNCELENMESİBu çalışmada, DN65 ve DN80 öçlülerindeki iki farklı vana, standart test metodu ANSI/ISA-75.02-1996’ya uygun olarak test edilmiştir. Bu test farklı akış hızlarında (2, 3 and 4 m/s) ve farklı açıklık açılarında (disk açılarında) (0, 10, 20, 30 and 40°) gerçekleştirilmiştir. 0° açıklık açısı tam açık vana konumu olarak kabul edilmiştir. Farklı açıklık açılarına tekabül eden akış alan yüzdeleri hesaplanmış, farklı akış hızlarında ve farklı vana açıklıklarındaki basınç kayıpları kaydedilmiştir.Deneysel veriler kullanılarak K ve Cv değerleri hesaplanmış ve K ve Cv değerlerini akış alan yüzdelerine bağlı fonksiyon şeklinde veren korelasyonlar geliştirilmiştir. Ölçüm belirsizliklerinin, performans katsayıları üzerindeki etkisini göstermek için belirsizlik analizi yapılmıştır. Sunulan korelasyonlar, iki farklı kelebek vananın performans katsayılarının belirlenmesinde etkin bir yöntem sağlar. Kayıp katsayısı, akışkanın, vanaya giriş hızından bağımsızdır. Fakat düşük akış alan yüzdelerinde vana çapına bağlıdır. Buna rağmen , or , şeklinde sunulan korelasyonlar, %65’ den daha büyük akış alan yüzdelerinde, iki farklı vana çapı için kullanılabilir. Debi katsayısı akışkan giriş hızından bağımsızdır fakat vana çapına bağımlıdır. DN65 ve DN80 ölçüsündeki vanalar için sunulan korelasyonlar; ve , akış alan yüzdeleri cinsinden debi katsayılarını verir. K ve Cv için verilen bu korelasyonlar, pratik kullanımlar için kabullenilir. Kelebek vana üreticileri ve tasarımcıları, farklı vana açıklık değerlerine göre, K ve Cv ‘ yi kolayca bulabilirler.Anahtar kelimeler: Kelebek vana, Kayıp katsayısı, Debi katsayısı, Belirsizlik analiziABSTRACTEXPERIMENTAL ANALYSIS OF THE PERFORMANCE COEFFICIENTS OF THE BUTTERFLY VALVES In the present work, two different butterfly valves, DN65 and DN80, were tested according to standard testing method ANSI/ISA-75.02-1996. The tests were performed at different flow rates such as 2, 3 and 4 m/s and at different valve opening angles such as 0, 10, 20, 30 and 40°. The opening angle 0° was considered as the fully open valve. The flow area percentages, , were calculated for different valve openings as 100, 82.64, 65.80, 50 and 35.72% and pressure drops, ΔP, were recorded for different valve openings at different velocities.Using the experimental data the loss and flow coefficients, K and Cv, were calculated and correlations were developed to give K and Cv as a function of the flow area percentage, . Uncertainty analysis was performed to show the effect of the measurement uncertainties on the performance coefficients. The proposed correlations provide an effective way to determine the performance coefficients of two different sizes of butterfly valves. The loss coefficient is independent of the inlet velocity but it is dependent of the valve size at the lower flow area percentage. However, when flow area percentage is more than 65% the proposed correlations, or , can be used for two valve sizes. Flow coefficient is independent of the inlet velocity but it is dependent on the valve size. The proposed correlations giving the flow coefficients as functions of the flow area percentage are and for DN80 and DN65 valves, respectively. Correlations for K and Cv which are given are appropriate for practical use. Manufacturer or designer of butterfly valves can find easily the corresponding K and Cv values for different valve opening. Keywords: Butterfly valve, Loss coefficient, Flow coefficient, Uncertainty analysis