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The adverse prejuduce against land readjustment method
Get PDFÜlkemizdeki imar planı uygulama yöntemleri içerisinde, arazi ve arsa düzenleme yöntemi uzun geçmişe sahip olmakla birlikte, kentsel alanlarda bir imar planı uygulama yöntemi olarak yoğun bir biçimde kullanılmadığı ve bu yönteme karşı önyargı bulunduğu bilinmektedir. Bu makalede, ülkemizde kentsel alanlarda imar planı uygulamalarında taşınmaz sahiplerinin arazi ve arsa düzenlemesi yöntemine karşı olumsuz önyargısı olup olmadığının saptanması ve eğer olumsuz önyargı varsa, bu yargının nedenlerinin ortaya konulması amaçlanmıştır. Ayrıca arazi ve arsa düzenlemesine karşı olumsuz önyargı olup olmaması ile imar planı uygulama yöntem tercihleri arasında ilişki belirlenmeye çalışılmıştır.In the implementation methods of the local physical plans in Turkey, although the land readjustment has a long past in Turkey, it is known that this method is not used in urban areas intensively and there is the adverse prejudice of landowners against to the land readjustment method. This paper aims to determine whether there is a adverse of landowners prejudice against to the land readjustment method or not and, if it exists, to determine the reasons of this. Additon to this, in the paper it is examined whether there is a relationship between the adverse prejudice and the method preferences. This study required a large-scale emperical analysis that attempted to assess the national position across the country. This study took the form of a questionnaire survey of municipalities selected through a stratified random sampling in Turkey. The final sample includes the responses from 468 municipalities. To reach the aims of this paper, descriptive statistics, cross- tabulation and chi- square test of indepence are used. In the result of the study, it is seen that municipalities tend to implementation of the local physical plans 15. and 16. titles method more than land readjustment methods. In the method preferences of municipalities the adverse prejudice of landowners against to the land readjustment is effective
Total quality management in construction industry and implementations in Turkey
Get PDFBu çalışmada, inşaat sektöründe kalite kavramı ve ürüne yönelik özellikler tanımlanmış, toplam kalite yönetiminin uygulanması, kurum kültürü kavramı, uygulamada karşılaşılan güçlükler ve elde edilen sonuçlar anlatılmıştır. Türkiye’de inşaat sektöründe toplam kalite yönetimi uygulamalarını değerlendirmek amacı ile yapılan alan çalışması kapsamında elde edilen bulgular incelenerek değerlendirmeler yapılmış, inşaat sektöründe toplam kalite yönetimi uygulamalarının başarılı olmasında ana faktör olarak belirtilen kültürel değişimin sağlanıp kurum kültürünün oluşturulması için önerilen araştırma modeli ve araştırma kapsamında ileri sürülen diğer varsayımlar sınanmıştır. Yapılan alan çalışması kapsamında inşaat sektöründe toplam kalite yönetimi uygulamalarının çoğunun başarısız olduğu gözlenmiştir.In this study, the concept of quality in construction industry and the features of product are identified.The implementation of total quality management in construction industry, the concept of corporate culture, the problems with implementing and the benefits of total quality management are explained. A research was made about the implementation of total quality management in construction industry. The objective of the research is to obtain data about implementations and analyse the research model advised in order to establish to corporate culture and the other hypothesis in research. Corporate culture has been identified as the primary factor that affects whether or not total quality management implementation efforts was successful. As a conclusion, it is observed that there is lack of top management commitment, leadership, understanding of necessity of culturel change to establish corporate culture, acceptance of internal customer concept, common education, motivation, coordination, team work, partnering, and participation of employees, sub-contractors and suppliers to quality. Therefore most of the implementations of total quality management in construction industry is unsuccessful. Total quality management values will only be established if managers are able to understand and accept total quality management?s concepts and values, identify the desired culture and manage the organisation in a manner consistent with these values. The success of quality depends on the genuine commitment to quality of every member of the organization
Tasarımda ilk kavramlar üzerine bütünsel bir model
Get PDFThis conceptual project presents a whole systemic tri-polar pattern as a ground for understanding and explaining design, creation and artifice. The basic emphasize is on the idea of disclosure of something hidden in lived experience. Be it a designer, a scientist, an artist or just an ordinary user, this model aims to understand and explain how does a human being as a meaningful, unique and complex character with his/her significant consciousness, disclose, objectify, systematize and communicate artifice and knowledge into the tangible and material world. Before all his duties, titles, appointments and roles that are socially constructed and run as designer, architect, engineer, lawyer, soldier, mother, father, manufacturer, doctor or user, here human being is firstly signified by the concept "whole". With all his/her physiological and psychological existence, human being is gathered in a whole of life that is described as continuous, uninterrupted and consequently unexplainable; it denotes a wholeness that cannot be influenced, penetrated or manipulated, that is already operating on its own, that cannot be expressed in language and cannot be known formally. Then, in order to understand and explain, he/she is intentionally distanced away from him/herself and broken down into pieces to reach to the initial pattern of network that defines an organization, a system and an operation. The whole will suddenly be opened part way and be reduced into language; the aim is to reach to the first contradictory meanings that make the whole understandable and knowable, and also to disclose the first dynamic model that animates those meanings. Unavoidably the methodological ground that this project will stand on belongs to philosophy, particularly on traditions of phenomenology and alethic hermeneutics. Unlike objective hermeneutics, for which there is a sharp dividing line between a studying subject and studied object, in "alethic hermeneutics", the polarity between subject and object is dissolved in the radical light of a more original unity with its focus on truth as an act of disclosure. Alethic hermeneutics dissolves the polarity between subject and object into a more primordial, original situation of understanding, characterized instead by a "disclosive structure"; the basic idea concerns the revelation of something hidden, rather than the correspondence between subjective thinking and objective reality. Consequently, the concept of whole in this paper as the primordial disclosive structure signifies two things at the same time: "the human being" showing the essential quality of being subjective and "the universe" showing the essential quality of being objective. How can something concealed in holistic aesthetic experience be expressed as a system in formal language as a question, asks for the search of first self-evident concepts that are initial clusters of meaning and are essentially irreducible to each other. In fact, in the beginning these clusters of meaning are deeply intertwined and sparse; showing a highly dynamic flux and affording no possibility for comprehension. Then, when an ultimate call for knowledge and linguistic explanation arrives, they become denser, thicker, cooler, they gain stability and disclose the three basic concepts that are presented as the poles of the first whole systemic triangle; 1. "world", signifying the material, the tangible, the bodily and the objective, 2. "doing", signifying the progressive, the linguistic, the social and the projective, and 3. "consciousness" signifying the immaterial, the intangible, the meaningful and the subjective. This triangle is whole systemic that its poles represent the steady states of these concepts stabilizing the system it denotes, while the tree sides facing the poles represent the dynamic states of these concepts making the system unstable. Finally in this project, when the arrived explanation returns to understanding, the basic triangle is re-heated, re-activated and encouraged to expand on a productive fractal pattern disclosing its outer layers. Despite the fact that it is originated in the basic Euclidean triangle, this layered structure promises countless possibilities of connections between the spatial poles and the temporal sides and affords highly complex formations. The nature of this network pattern is presented as a model of the hardware of the whole and as the necessary infrastructure enabling the disclosure of lived experience and tacit knowledge through artifacts and formal and systemic knowledge. Keywords: Design theory, philosophy of design, holistic systems, whole.Bu çalışma “tasarım” kavramıyla dile getirilen insan özelliğinin anlaşılmasını ve açıklanmasını amaçlar. Uyguladığı tümdengelimci bütünsel yöntem onu tasarım özelliğinin açığa çıktığı nokta olarak insan üzerine bir çalışmaya da dönüştürür. Toplumsal olarak kurulmuş görevleri ve rolleri bir yana, insana öncelikle “bütün” kavramıyla işaret edilmektedir. İnsan tüm fiziksel ve psikolojik varlığıyla kesintisiz ve sürekli, dolayısıyla da açıklanamaz olarak işaret edilen bir yaşam bütünlüğünde toplanmakta, daha sonra da anlama ve açıklama yolunda aralanıp dağıtılarak ondaki organizasyonu, işleyişi ve sistemi işaret eden ilk kavramsal örgüye ve ağ desenine ulaşılmaya çalışılmaktadır. Böyle bir üst kuram denemesinin dayanacağı yöntemsel düzlem kaçınılmaz olarak felsefeye, özellikle fenomenolojiye aittir. Bütün kavramı ayrıca, tasarımcının tasarım sürecinde, tasarım araştırmacısının da araştırma sürecinde yapıp ederken yöneldiği, karşı karşıya kaldığı, konu edindiği, iletişime girdiği ve orada yerleşerek işleyişine katıldığı esas ve zorunlu varlığı anlatmak için kullanılmaktadır. Böylece bu çalışma, insanın gerçek dünya yaşamındaki güncel çelişki ve sorunlara da atıfla, ele aldığı konuyla ilgili kuramsal temelleri ele alışta, anlamada, değerlendirmede ve düşüncede bir yenilenmeyi amaçlamaktadır. Metnin ilerleyen bölümlerinde, dile gelmeyen ve biçimsel olarak bilinemeyen yaşam bütünlüğü bir anda dile indirgenecek ve onu bilinebilir ve anlaşılabilir kılan ilk kavramlara ve bu kavramlara hayat veren ilk devingen modele ulaşılmaya çalışılacaktır. Sonuç bölümünde, esas özelliklerinden biri tasarlamak olan bu bütün için birbirleriyle kurulan ve birbirlerine göre korunmuş durumları ve devinimleri olan ilk üç kavram ve bunları açığa çıkaran, üretken ağ deseni önerilecektir. Anahtar Kelimeler: Tasarım kuramı, tasarım felsefesi, bütünsel sistemler, bütün
Development of office rent prediction model for Istanbul
Get PDFIn the last quarter of previous century, economic, social and technological development caused a change in employment structure and an increase in the share of service sector. Demand for modern office space was driven by faster growth in finance, insurance, real estate (FIRE) sub-sectors. Existing office inventory could not meet modern space requirement, hence new metropolitan areas has started to develop. Office demand has an important role in metropolitan urban development and emergence of new subcentres. Therefore, office rent prediction is a crucial issue in decision - making of new office investments and planning strategies. Office rent prediction models have been the major concern of academic research since 1980s. Hedonic office rent prediction models which are the most common method based on multiple regression are well established in the literature. A wide range of variables, categorised as econometric, architectural, spatial and tenure rights, are used in these models for various cities. It is difficult to incorporate large number of variables into a simple mathematical model. As a result, the need has arisen to reduce or group the excessive number of variables to achieve simplier mathematical expressions with greater explanatory power. In the light of previous studies, some difficulties can arise in gathering data and applying the hedonic theory. The major difficulty lies within the hedonic regression models is the multicollinearity problem that may exist between a large number of independent variables. The common solution is exclusion of some variables depending on significance level or using "stepwise" or "backward" procedure in regression models. Another problem with development of rent prediction model is selection of dependent variable. In the literature, asking rent is preferred in some models while contract rent or effective rent are used in others, as the dependent variable. It is reported that the use of contract or effective rent instead of asking rent, can provide more accurate predictions. However, it is difficult to obtain sufficient contract data from real estate firms, due to confidentiality and competition. The aim of this study is to examine the problem with construction of an office rent prediction model and development of a viable prediction model for Istanbul. For this purpose, a proposed regression model is constructed with using asking rent, gross and net contract rents, as dependent variable for 1996 - 2006 period. First, full model is developed with thirty-four variables, then a reduced model is constructed by eliminating some variables using "backward" procedure in standard regression model. Finally, the performances of prediction models are compared according to R-squared and t-statistics. In addition, Akaike Information Criteria and Schwarz Bayesian Criteria are also employed to test the accuracy of proposed models. Based on the findings of most accurate model, the significant variables are defined for Istanbul office market. The similarities and differences from literature findings are discussed. The results confirmed that use of contract rents instead of asking rents can provide robust predictions with higher explanatory power. Besides, the reduce models offer better solution for multicollinearity problem. Building and locational variables are found the most significant office rent determinants for Istanbul metropolitan areas. The findings point out importance of accessibility and locational prestige in site selection for new office investments. Especially, distance from the CBD and important transportation nodes (Bosphorus Bridge, highway connection) have an important role to explain in rental change, in line with global literature. Results reveal that secondary centres gain importance. This strengthens the assertion that the tendency for office investment in Istanbul is away from the traditional centre (CBD) and closer to secondary centres. However, rental values are still higher in the CBD. For further studies, it is aimed to increase number of data to obtain more accurate prediction model for Istanbul. It is expected that office rent prediction models will be helpful to determine new office areas. Keywords: Istanbul, office market, rent prediction model, hedonic regression, multicollinearity.Geçen yüzyılın sonlarında meydana gelen ekonomik, sosyal ve teknolojik gelişmeler işgücünün sektörel yapısının değişmesine ve hizmetler sektörünün payının artmasına neden olmuş ve modern ofis alanlarına olan talebi de arttırmıştır. Metropoliten kentlerin büyümesi ve yeni alt merkezlerin oluşmasında ofis alanı talebi önemli rol oynamaktadır. Bu nedenle, ofis kira değerlerinin tahmini gayrimenkul yatırımları ve planlama stratejilerinin belirlenmesi açısından büyük önem taşımaktadır. Literatürde çoklu regresyon tabanlı hedonik kira tahmin modeli sıklıkla kullanılmaktadır. Ancak hedonik teorinin uygulanmasında ve veri temini konusunda bazı güçlüklerle karşılaşılmaktadır. Özellikle çok sayıdaki bağımsız değişken arasında ortaya çıkan çoklu bağlantı (multicollinearity) sorunu değişken eleme teknikleri ile ya da önem derecelerine göre bazı değişkenlerin modelde ihmal edilmesi ile çözülmeye çalışılmaktadır. Bu çalışmada İstanbul için bir ofis kira değeri tahmin modeli geliştirilmesi amaçlanmıştır. 1996 – 2006 yılları arasındaki ofis kira değerleri ve kira değerini etkilediği iddia edilen 34 farklı değişken kullanılarak İstanbul metropoliten alanında seçilen dört ana ofis bölgesi için bir kira tahmin modeli geliştirilmiştir. Standart regresyon modeli içinde varolan değişken eleme yöntemi (backward) ile değişken sayısı azaltılarak indirgenmiş bir model oluşturulmuştur. Ayrıca elde edilen tahmin modellerinin performansı açıklayıcılık güçleri, t-istatistiklerine göre karşılaştırılmış, Akaike Bilgi Kriteri ve Schwarz Bayes Kriteri kullanılarak önerilen modellerin doğruluğu test edilmiştir. Böylece elde edilen en sağlıklı modelin sonuçlarına göre, özellikle merkeze olan mesafe, önemli ulaşım noktalarına (Boğaz Köprüsü, otoyol bağlantısı) erişim ve konum prestiji İstanbul metropoliten alanı ofis kiralarındaki değişimi açıklamada en önemli değişkenler olmaktadır. Anahtar Kelimeler: İstanbul, ofis pazarı, kira tahmin modeli, hedonik regresyon, çoklu bağlantı
Depremlerin oluş nedenlerine ilişkin Bizans teorileri
Get PDFThis study attempts to analyze the Byzantine attitudes towards earthquakes which the city of Constantinople and its surrounding areas confronted throughout the existence of the Byzantine Empire, between the fourth and the fifteenth centuries, in the light of the accounts of the Byzantine chroniclers and the historians. The way in which our sources discuss and document the earthquakes provides the reader with a prism through which he or she can gain a perspective on the Byzantine worldview. For example, what do they think cause earthquakes? It will be seen and discussed in detail that, during the existence of the empire, to explain the cause(s) of the earthquakes, the Byzantines not only refer to the Bible, but also to the scientific explanation of Aristotle, and the popular beliefs. However ,in general the Byzantines regarded sins above all as responsible for the occurrence of the earthquakes, and there has not been a substantial change in their mentality for the causes of the earthquakes throughout the existence of the Empire. To support the idea that earthquakes were a divine punishment visited upon the Byzantines, the Church tried hard to show that God brought earthquakes to punish people because of their many sins. After the occurrence of an earthquake people turned to prayer and propitiation together and they believed that by confessing their sins they could stop the earthquakes. Keywords: Earthquake, the city of Constantinople, Byzantine Empire.Bu çalışmada Bizans İmparatorluğu’nun başkenti Konstantinopolis şehri ve etrafındaki yerleşim birimlerinde imparatorluğun varoluş süresi boyunca, dördüncü ve onbeşinci yüzyıllar arasında, meydana gelen depremler tarihsel veriler ışığında değerlendirilerek Bizanslıların depremleri nasıl algıladığı konusu üzerinde durulmaktadır. Modern araştırmacıların ilgi alanına pek girmeyen bu konunun ele alınmasıyla, Bizanslılar arasında depremlerin oluş nedenleriyle ilgili olarak ortaya atılan bilimsel, dini ve popüler görüşler yardımıyla Bizans zihniyeti hakkında somut bir bilgiye ulaşılmaya çalışılmıştır. Fakat çalışmamız boyunca görülecektir ki, bütün bu bilimsel, dini ve popüler görüşlerin üzerinde, Bizanslılar genel olarak depremlerin Tanrı’ya karşı işledikleri günahlardan dolayı meydana geldiğini düşünmekteydiler. Anahtar kelimeler: Deprem, Konstantinopolis şehri, Bizans İmparatorluğu
An analytical valuation technique applied to industrial companies in Istanbul Stock Exchange
Get PDFBu çalışmanın amacı kantitatif değerleme tekniğini (KDT) kullanarak bir şirketin teorik değerini hesaplamaktır. Elde edilen sonuç gerçek piyasa fiyatı ile karşılaştırılıp şirketin hissesinin primli mi, iskontolu mu yoksa değerinde mi işlem gördüğü belirlenir. Analiz ortamı olarak kullanılan tablolama programının girdilerini kesitsel veriler (1995-2001 yılları arası mali tablolar) ve zaman serileri (düzeltilmiş hisse senedi fiyatları) oluşturmaktadır. Gerçek piyasa değerleri olarak ise İstanbul Menkul Kıymetler Borsası’nda oluşan fiyatlarlar alınmaktadır. Sonuçta piyasa fiyatlarının gerçeği yansıttığı düşünülürse KDT, bu değerleri %36’ya yakın bir doğrulukla tahmin edebilmektedir. Diğer yandan piyasa fiyatlarının gerçek firma değerlerini temsil etmediği düşünülürse, KDT’nin yatırım tavsiyelerini kullanarak hazırlanan portföyler, piyasa endeksinin oldukça üzerinde getiri sağlamaktadırlar. Anahtar Kelimeler: Kantitatif Değerleme Tekniği (KDT), proforma mali tablolar, temel nakit akımları.The aim of this paper is to construct the theoretical value of a company using the quantitative valuation technique (QVT). The results are then compared to the actual market prices in order to determine whether each company's stock is trading at a premium, at a discount or at par. The analysis tool is a spreadsheet application fed by cross-sectional data (financial statements covering 1995-2001 period) as well as by time-series data (the adjusted stock prices). Real life comparisons are made vis-à-vis the prices established in the Istanbul Stock Exchange. At the end, if market prices are considered as correct, QVT can estimate them with approximately 36% accuracy. If market prices are considered to be misrepresenting the true company values, on the other hand, the portfolios constructed via QVT's investment recommendations considerably outperform the major market index. The main aim of this research is construct the theoretical structure of the quantitative valuation technique (QVT) and realized its practical application according to the help of Microsoft Excel. At the end of this analyze, the outcome of the method of the quantitative valuation technique (QVT) is compared to real life market to get the performance of the QVT. The industrial companies are being selected from the index of the Istanbul Stock Exchange100 for comparision. Keywords: Quantitative Valuation Technique (QVT), proforma financial statements, fundamental cash flows
Türk müziğinin popülerleşme sürecinde film müzikleri ve Sadettin Kaynak
Get PDFBoth musical and social identities of Sadettin Kaynak had direct projections on the course of popularization, and this has been the main reason to affiliate this process of popularization with him. Kaynak, during the last quarter of the Ottoman Empire and the first quarter of the Republic of Turkey, was one of the most important composers of Turkish music. He was prominent during the transformation from traditional to popular style, with his music education, music knowledge, his taste of music which are apparent in his performances and compositions. His use of maqams and usuls, the freedom he brought to melodic structure, form, lyrics and rhythmic structure, his employment of folk music material in his melodic structure, his notion of instruments competing with the vocal element (aranağme-arasaz), his new form called “fantasy” and his style of performance were also significant and they reflect how Turkish music changed and how it was popularized. Sadettin Kaynak gave concerts in his tuxedo in many European cities including Paris and Berlin. He was a soloist and gazelhan as well as a reputable composer and a performer who tried to maintain a vivid contact with the social structure of the era throughout his artistic life. He said: “I want to make music for the taste of the public and I want to popularize my music whenever possible”, and the media of the time, that is the record industry, radio, cinema and music halls, gave him the chance to realize his intention. Apart from his identity as a musician, he was also a religious official and a hafiz who studied religion in the Faculty of Theology. He served as the imam of Sultan Selim and Sultanahmet Mosques with his robe and turban on and sang ezan on religious records produced by the Columbia Company. With respect to his origins, Sadettin Kaynak, a religious official and imam, was of great importance and meaning as a composer of Turkish music with his music he started to compose in the cultural environment of Turkey in the first quarter of the 20th century with this identity. Sadettin Kaynak, considering the socio-economic and political conditions of his time, who had been a great intellectual and artist of the Republic, achieved something very difficult, with these two contradictory identities indeed supporting each other. He became famous and popular especially for his film scores, which he began in the 1930s. After the prohibition of singing songs from Arabian movies of Egyptian origin in Arabic, Kaynak became a composer of new songs composed according to the subject matter of Arabic songs or “adapted” songs which were made by writing Turkish lyrics to the original ones. Out of his 669 compositions, Kaynak composed 218 pieces for 14 Turkish films and another 47 pieces for Egyptian films. These pieces were performed by the most famous and popular artists of the period not only for the films but also for the records. Moreover, these works of Kaynak were performed in the popular nightlife clubs of the period, “gazinos”. Consequently, by means of all these factors, Kaynak had an important role in the popularization of Turkish music. The object of this thesis is to show Sadettin Kaynak’s personal, social and musical identities and also, the process of change that Turkish music experienced, in parallel to his life between the years 1895-1961, from not only a musical perspective but also by considering economic, political and ideological occurrences in the society. In this study, we will explain how music was popularized and was used to spread western culture, its values and modernization to layers of society within the modernization project after the Republic of Turkey was founded. Sadettin Kaynak will be analyzed with his different identities and particularly, popularization of Turkish music will be analyzed with his identity as a composer of film scores by inductive and deductive reasoning, that is from the period to Kaynak and from Kaynak to the period. In order to realize this study, three methods were employed: Analysis of audio- visual sources as well as the literature review, scanning of period newspapers and magazines between 1929 and 1961 and music analysis. These methods were applied within “industry of culture” and “culture of masses” notions and theoretical approaches about criticism of culture.Sadettin Kaynak, Türk müziğinin en sancılı dönemi Osmanlı’nın son ve Cumhuriyetin ilk çeyreğinde müzik eğitimi, icrası ve bestelerindeki müzik anlayışı, gerek melodik yapıya ve forma, gerekse söz yapısına ve ritmik yapıya getirdiği serbestlik, melodik yapıda halk müziğinden faydalanması, söz unsuru ile yarışan bir saz anlayışı, “fantezi” adlı yeni formu ile geleneğin popüler tarza dönüşmesinde Türk müziğinin en önemli bestekarlarındandır. O’nun film müziği besteciliği bu dönüşümü sağlayan en büyük etkenlerdendir. Cumhuriyet politikaları doğrultusunda geleneksel müziği unutturmak amaçlı başlatılan yasaklama süreci, halkın radyolarda Arap müziği yayınlarını aramaya başlamasına, ardından II. Dünya Savaşı ile kapanan Avrupa pazarlarının yerini Mısır filmlerinin almasına sebep olmuştur. 1938’de filmlerin şarkılarının Arapça söylenmesi yasaklanınca; şarkılar konularına göre yazılan yeni şarkılarla ya da üzerlerine Türkçe sözler yazılarak seslendirilmeye başlanmıştır. Böylelikle “Adaptasyon” adı verilen şarkı türü ortaya çıkmıştır. Bu anlayışın en önemli ismi de Sadettin Kaynak olmuştur. Kaynak, tespit edilen 669 eserinin 218 tanesini, 61 film için bestelemiştir. Bu besteler dönemin ses sanatçıları tarafından plaklara da okunmuş, eğlence mekanları icralarının da vazgeçilmezi olmuştur. Tüm bu unsurlar Türk müziğinin halka ulaşıp popülerleşmesini sağlamıştır. Bu çalışmanın amacı, gerek tümdengelim yöntemiyle yaşadığı dönemin genel özelliklerinden Sadettin Kaynak’a, gerekse tümevarım yöntemiyle Sadettin Kaynak’ın sosyal, müzikal kimliklerinden yaşanılan döneme ulaşılarak, O’nun film müziği besteciliği paralelinde Türk müziğinin popülerleşmesini incelemektir. Tarihsel araştırma, gazete / süreli yayın taraması ve müzikal analiz yöntemlerinin kullanıldığı çalışmada bu yöntemler popüler kültür / kitle kültürü teorileri bağlamında değerlendirilmiştir. Anahtar Kelimeler: Türk müziği, Sadettin Kaynak, film müziği, popülerleşme
Ligand effects in metal catalyzed reactions
Get PDFMetal katalizli reaksiyonlarda, özellikle geçiş metali, bileşiği veya organometalik bileşiği katalizör olarak kullanılır. Metal katalizinde ligand, katalizör yapısında veya reaksiyon ortamında katılır. Ligand kullanılarak, reaksiyonun hızı, verimi ve kimyasal seçiciliği kontrol edilebildiği gibi, asimetrik ligand kullanılarak stereoseçicilik de sağlanabilir. Metal katalizli reaksiyonlarda ligandla hızlandırılmış kataliz, lâboratuvarda ve endüstride çok önemlidir; fakat ligandla yavaşlatılmış kataliz konusunda çok az araştırma yapılmıştır.Alkenlerin osmiyum katalizli dihidroksillenmesi, ter-amin ligandlar kullanılarak ligandla hızlandırılmış veya yavaşlatılmış olarak yürütülebilir. Grignard ve organolityum reaktiflerinin bakır katalizli reaksiyonlarında reaksiyonun verimi ve kimyasal seçiciliği, ligandlı Cu(I) bileşikleri ile kontrol edilebilir. Anahtar Kelimeler: Dihidroksilleme, eşleşme, kataliz, ligand, metal katalizi.For metal catalyzed reactions, generally a transition metal, a transition metal compound or an organometallic complex is used as a catalyst. A ligand can act either as complexed to the metallic catalyst or as one of the reactants. A ligand has four different modes of operation: (i) to accelerate or decelerate the catalysis, (ii) to control the product yield, (ii) to control chemoselectivity, and (iii) to provide stereocontrol in the case of chiral ligands. The use of ligand accelerated catalysis has become increasingly important for asymmetric synthesis both in laboratory and industrial scale; however, ligand decelerated catalysis has not been investigated in detail. In osmium catalyzed dihydroxylation of alkenes in the presence of nitrogen donor ligands, ligand accelerated or decelerated catalysis can take place as a result of some combination of substrate alkene and ligand. Cu(I) catalyzed C-C and C-heteroatom coupling reactions of Grignard reagents and organolithiums have revealed that reaction yield and chemoselectivity can be controlled by ligand complexed Cu(I) catalysts and one shoud not use automatically CuI, the popular catalyst for coupling, but rather examine several Cu(I) compounds and their complexes to find the optimal one. A research on "ligand controlled catalysis" is offered for optimization of all reaction parameters, i.e. rate, yield, chemo- and stereocontrol in metal and ligand catalyzed reactions. Keywords: Dihydroxylation, coupling, catalysis, ligand, metal catalysis
Prediction of the parameters used for scaling of periodic components of monthly flows
Get PDFBölgesel modeller, ölçeklendirme parametreleriyle boyutsuzlaştırılan gözlem dizilerinin analizine dayanmaktadır. Bölgesel modellerden yapılan noktasal kestirimlerin etkinliği büyük ölçüde, ölçeklendirme parametrelerinin etkin şekilde kestirilmesine bağlıdır. Ortalama ve standart sapma gibi bazı ölçeklendirme parametrelerinin fizyografik ve iklimsel faktörlere bağlı olarak kestirimi için literatürde çeşitli ampirik ve istatistiksel öneriler mevcuttur. Ayrıca asimetrik dağılıma sahip hidrolojik değişkenlerin ölçeklendirme parametreleri arasında çoğu zaman güçlü istatistiksel ilişkiler bulunmaktadır. Bu çalışmada, Ceyhan ve Seyhan havzaları örneğinde aylık akışların periyodik bileşenlerinin bölgesel analizinde gereksinim duyulan ölçeklendirme parametrelerinin, doğrudan havza alanına ve kendisi de bir ölçeklendirme parametresi olan genel ortalama akışa bağlı olarak kestirilmesi konusu incelenmiştir. Söz konusu değişkenler arasındaki doğrusal ve üstel ilişkiler, klasik, ağırlıklı, doğrusal ve doğrusal olmayan en küçük kareler teknikleriyle araştırılmıştır. Araştırma sonucunda, aylık akışların modellenmesinde gerek duyulan ölçeklendirme parametrelerinin % 80'ler civarında bir determinasyon katsayısıyla havza alanlarına bağlı olarak, % 95'in üzerinde bir determinasyon katsayısıyla da genel ortalama akışa bağlı olarak kestirilebileceği sonucuna varılmıştır. Ölçeklendirme parametrelerinin kestirimi için regresyon katsayıları doğrusal olmayan klasik veya ağırlıklı en küçük kareler yöntemleriyle hesaplanan üstel modellerin daha elverişli olduğu saptanmıştır. Anahtar Kelimeler: Bölgesel model, ölçeklendirme, regresyon analizi. Monthly river flows are traditionally considered as a stochastic time series composed of periodic components in the mean and standard deviation, and stochastic components with a constant or periodic serial dependent structure. In the modeling of monthly river flows, the second order stationary stochastic components can be derived by removing either the observed values of the periodic parameters or their fitted functions (Fourier transformed forms) with an appropriate number of significant harmonics. The first approach is often so-called the non-functional (or nonparametric) approach while the second one the functional (or parametric) approach, in the hydrology literature. The functional approach is a parsimonious one since it necessitates fewer numbers of parameters to describe the periodicities in the basic parameters of the hydrologic time series. Despite the fact that periodic parameters have great importance in the simulation and synthetic data generation studies at the places where streamflow measurements are inadequate for the time series modeling, no attempt on the regionalization of the periodic parameters of the hydrologic time series has been meet in the literature. Very recently, Özçelik (2007) has proposed some regionalization approaches based on the standardized periodic parameters and on the standardized harmonic functions. He has used clustering techniques to identify homogeneous subregion. Almost all regional models especially the regional models of the periodic parameters rely on the observations un-dimensioned by the scaling parameters. Therefore, estimation of the scaling parameters has a critical importance for the point estimations of regional models. There are several proposals based on the basin physiographic, morphologic and climatologic properties to estimate the scaling parameters, besides the indirect estimation of the scaling parameters via some general statistics such as the overall mean, general standard deviation, which can be more easily and accurately defined by some empirical-statistical techniques. To get basin physiographic and climatologic properties requires a time and labor consuming process. However, for most cases, it is possible to get the drainage area of the required flow section. On the other hand, it is known that there are strong dependencies among the parameters of asymmetrically distributed processes. Therefore, the scaling parameters can be estimated reasonably by using the overall mean - which is also a scaling parameter-and the drainage areas of the flow sections. The study presented herein is a summary of the regional regressions of the various scaling parameters on the drainage area, which is a dominating physiographic factor among the others, and on the overall mean. Applications on the monthly data recorded at 30 streamgaging stations in the Seyhan and Ceyhan river basins of Turkey have revealed that of the drainage area based models; the linear models are not satisfactory especially for basins with small area; the nonlinear models are not reliable for the basins with large area, though the ones set by the linear least square technique (using log-transformation) are well fit to observed values of scaling parameters for the basins with small area. Contrary, for the overall mean based models, almost all linear and nonlinear models set by the linear and nonlinear least square techniques produce reasonable results. However, the weighted least square estimations have improved the effects of sampling errors on the model reliabilities. The scaling parameters can be estimated from the power type regressions of the scaling parameters on the drainage area with a coefficient of determination around R2 = 0.80, while from the power type regressions of the scale parameters on the overall mean with R2 = 0.95. Accordingly, it is concluded that using the general means reliably estimated by short-term records or records of surrounding stations, the scaling parameters can be easily and accurately estimated for practical applications. The regression models set by the method of nonlinear least squares can be preferred to the others in estimation of the scaling parameters. Finally, the point estimates of regional models can be realized conveniently by using the estimated scaling parameters for the required flow sections. Keywords: Regional model, scaling, regression analysis.
Zamana bağlı boru akışındaki ısı geçişinin sayısal olarak incelenmesi
Get PDFUnsteady turbulent flows and the heat transfer which occur in pipe flows take place in a broad range of engineering devices. Investigation of such phenomena and understanding the underlying mechanisms would be very beneficial for the design of such practical devices, i.g. preswirl systems in gas turbine cooling and inlet manifolds in automotive engines. Analyzing the fluid flow problems by numerical simulations has gained such maturity within the last decade that they are utilized as an important design and analysis tool in a wide and ever increasing range of applications. Likewise, convective heat transfer is also analyzed using computational methods. Therefore, validation of numerical methods is a crucial matter for the modeling of such phenomena accurately. Validation of computational procedures has been carried out by some authors, but they were rather interested in solving steady-state problems. Therefore, there is a lack of validation studies of numerical predictions for unsteady convective heat transfer problems. This is the scope of the present investigation. In this study, unsteady turbulent pipe flow which includes convective heat transfer has been investigated computationally. The numerical predictions have been validated by considering the recent experiments of Barker and Williams. This numerical study has been carried out using the general purpose code Fluent as basis, which utilizes finite volume method to discretize the governing equations, and a pressure correction formulation to handle the pressure-velocity coupling. Ensemble averaged continuity, Navier-Strokes, and energy transport equations have been solved for the incompressible, unsteady, 2D, axisymmetrical, turbulent pipe flow. Various two-equation turbulence models have been tested and examined in different computations in order to validate the models, since they are often used in industrial applications. Those are, namely, the standard k- , RNG k- , and Realizable k- turbulence models. A one-equation model has also been used in steady-state analysis, for comparison. As the modeling of near wall region is very important and have influence on convective heat transfer, different models have been employed. Those are, namely, some formulations including the standard or non-equilibrium wall-functions, and two-layer-zonal methods. Although the two-layer methods which resolve the near wall region with fine cells can principally produce better predictions the wall functions approach has been mainly used in this investigation because the two-layer methods demand high computational costs, and their use is still restricted to practical applications. For steady-state analysis, the predictions have been validated by empirical correlations. The predictions agree quite well with the empirical values where no substantial differences were observed in performance of two-equation models considered. On the other hand, the two-layer methods did not offer a significant advantage over wall-function approach. The transient analysis has been carried out with step-like, pulse-like and sinusoidal perturbations of the flow rate at different Reynolds numbers, by mainly using, the standard k- turbulence model with the standard wall-functions. The computational results have been compared with the experiments. It has been observed that in step-like changes the amount of wall heat flux could be predicted well, but the time delay of the heat flux response to the change of flow rate could not be predicted. In pulse-like changes the peak values and the variation of the wall heat flux with respect to time could be predicted well, especially at higher Reynolds numbers. However, the time delay of wall heat flux response to the change of flow rate has been fairly under-predicted. In sinusoidal perturbations, ensemble averaged measurements of wall heat flux could be predicted reasonably well. However, the deviation between the peak values of the computed wall heat flux and the measurements became greater with increasing relative amplitude of the flow rates. Computations could not predict sufficiently the form of the measured ensemble averaged heat flux curve with respect to time, which deviate from the sinusoidal shape, especially at highest relative amplitude of the flow rate. This might be due to low Reynolds number effects around temporally minimum flow rates during oscillations. It has been shown that the mean computed wall heat flux was not influenced by sinusoidal perturbations, and this finding was also in agreement with the experiments very well. Two-layer-zonal methods did not improve the observed time delay between the wall heat flux and the centerline velocity for the considered cases. Keywords: CFD, turbulence models, heat transfer, pipe flow. Bu çalışmada, türbülanslı boru akışındaki taşınım yolu ile gerçekleşen ısı geçişi zamana bağlı sayısal olarak çeşitli yöntemlerin kullanımı ile modellenip, incelenmiştir. Bu maksatla, muhtelif türbülans modelleri ile cidar yakını modellemesi yaklaşımları denenerek, bu modellerin performansı etüd edilmiştir. Çalışmaya ilk olarak daimi akış koşulu altındaki analizler ile başlanmıştır. Daimi hal için, literatürde yer alan ampirik ifadelerden türetilen Nusselt sayıları hesaplamalardan elde edilen Nusselt sayıları ile karşılaştırılarak, hesap değerleri doğrulanmaya çalışılmıştır. Buna göre, denenen muhtelif iki denklemli türbülans modellerinin birbirlerine çok benzer neticeler ürettikleri, dolayısıyla bu modellerin daimi hal analizlerindeki performansları arasında önemli farkların bulunmadığı gözlemlenmiştir. Zamana bağlı hal analizlerinde ise, daha çok, iki denklemli türbülans modellerinin cidar fonksiyonlarıyla birlikte kullanımına odaklanılmıştır. Bunun yanı sıra, cidar fonksiyonlarının kullanılmadığı iki tabaka bölgeli model de bazı haller için kullanılarak elde edilen çözümlerin iyileştirilebilme olasılıkları incelenmiştir. Basamak şeklinde, darbe şeklinde ve sinüzoidal şekilde akış debisinin değiştiği muhtelif zamana bağlı akışlarda çeşitli sayıda Reynolds sayıları ele alınmıştır. Yürütülen hesaplamalardan elde edilen sonuçlar deneyler ile kıyaslanarak sunulmuş, ve elde edilen hesap neticelerinin ölçüm değerlerini öngörebilme kabiliyeti sorgulanmıştır. Burada, hız ve ısı akısı gibi parametrelerin zamana bağlı değişimlerinin hem nitelik hem de nicelik olarak, özellikle yüksek Reynolds sayılarında, makul bir biçimde öngörülebildikleri tespit edilmiştir. Ancak diğer taraftan, cidardaki ısı akısı cevabındaki gecikme gibi bazı hususların hesaplamalar tarafından yeterince yakalanamadığı da gözlemlenmiştir. Anahtar Kelimeler: Sayısal akışkanlar dinamiği, türbülans modelleri, ısı geçişi, boru akışı. 
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