237 research outputs found

    Water Exchange through Canal İstanbul and Bosphorus Strait

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    The Turkish Straits System (TSS) regulates the transports of water, material and energy between the Black Sea and the Mediterranean Sea. Amidst existing environmental threats to the region surrounding İstanbul, the environmental footprint of the proposed Canal İstanbul project needs to be evaluated through methods of natural science. We take the elementary step to answer the particular problem of coupled strait dynamics by adding the Canal to an existing hydrodynamic model and estimate changes in their common response. Compared to the virtually unmodified exchange flow in the Bosphorus, the flow in the Canal has a weak lower layer current component, contrasted with intense currents at the exit controls at its junction with the Marmara Sea. The net flux through this simplest hypothetical TSS configuration is considerably increased for a given sea level difference across the system. The modified regime is expected to have climatological consequences

    Türkçede Eşgönderge Örüntüsü

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    Bu yazıda Türkçe'nin tümce yapısı yönetim ve bağlama kuramı çerçevesinde incelenecek ve belirtilen eşgönderge örüntüsünün Türkçe'nin içinde olan yapısal bir kısıtlamadan kaynaklandığı gösterilmeğe çalışılacaktır

    Yönetim ve Bağlama Kuramı Sözlüğü

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    Yönetim ve Bağlama Kuramı Sözlüğ

    Türkçede Ortaç Yapısı

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    Bu çalışma Türkçe'deki ortaç yapısını Yönetim ve Bağlama kuramı çerçevesinde incelemeği amaçlamaktadır. Yönetim ve Bağlama kuramı dillerdeki yapısal özellikleri bir dizi evrensel ulam ve ilkeler ile açıklayan, dillerde görülen bu özelliklere betimlemeli bir yaklaşımdan öte açıklayıcı bir yöntemle yaklaşmağı yeğleyen bir dilbilim kuramıdır. Bu kuram çerçevesinde, diller arasında gözlemlenen ayrımlar yalnızca yüzeysel yapıda görülen bir dizi parametrik ayrımlara indirgenmekte, bu parametrelerin niteliğini ve boyutlarını belirleyen ulam, ilke ve yankuramlan tüm insan dillerinin özelliklerini belirleyen evrensel dilbilgisinin birer parçası olarak algılanmaktadır

    Numerical Simulation of incompressible laminar flow over three dimensional rectangular cavity

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    Bu çalışmada basit bir geometriye sahip olmasına rağmen oldukça karmaşık bir akım yapısı sergileyen ve gerek askeri gerekse de endüstriyel pekçok uygulamada sıkça karşılaşılan iki veya üç boyutlu kaviteler üzerindeki zamana bağlı, sıkıştırılamaz akış sayısal olarak incelenmiştir. Bu çalışmanın ana amacı, düşük Reynolds sayılarındaki kavite akışı hakkındaki bilgileri ilerletmek ve 3 boyutlu kavite akışı ile 2 boyutlu (2B) veya 3 boyutlu (3B) kavite üzerindeki akımın 3 boyutluluk etkilerini incelemektir. Sayısal çalışmada, Navier-Stokes denklemleri, zamana bağlı, 3B’lu, sıkıştırılamaz bir akış için Fluent ticari yazılımıyla sonlu hacimler yöntemi kullanılarak çözülmüştür ve türbülans modellemesi için de Large Eddy Simülasyonu (LES) yaklaşımı kullanılmıştır. Çalışmada uzunluğunun derinliğine oranı (L/h) 4 olan ve uzunluğunun genişliğine oranı (L/w) 0.8 olan dikdörtgensel bir kavite ele alınmıştır. Yaklaşmakta olan akımın tipi laminer olarak seçilmiştir. Kavite derinliği ve serbest akış hızına göre hesaplanan Reynolds sayısı 4000’dir. LES kullanılarak yapılan sayısal çalışmanın doğruluğu, 2 farklı Re sayısı için (4000 ve 13000) için Özsoy ve diğerleri (2005)’nin yapmış olduğu deneysel çalışma kullanılarak sağlanmıştır. Doğrulama yapıldıktan sonra 2B’lu bir kavite üzerindeki akımın 3B’lu yapısı ile, 3B’lu bir kavite üzerindeki akış yapısı sırasıyla incelenmiştir. Hem 2B’lu hem de 3B’lu kavite akışının içerdikleri akım ayrılması, kayma tabakası, vorteks üretimi, vorteks yayınma mekanizması ve vorteks-duvar etkileşimleri nedeniyle oldukça karmaşık bir yapıya sahip oldukları gözlemlenmiştir. 2B’lu ve 3B’lu çözümlerin kavite orta düzleminde yapılan karşılaştırmaları ortalama akış büyüklükleri cinsinden benzer sonuçlar verse de türbülanslı büyüklükler açısından farklılıklar içerdiği ve özellikle duvara yakın bölgelerde duvar etkisi nedeniyle oldukça farklı bir akış yapısı sergiledikleri gözlemlenmiştir. Anahtar Kelimeler: Kavite akışı, LES, Vorteks, Laminer akım.There are many engineering structures which require some form of cavities on their surfaces in order to perform the task they are designed for.  However, these cavities can also be a source of various problems if structures with cavities are subjected to flow conditions. It is well known that the flow over a cavity is a complex phenomenon due to there usually being strong pressure, velocity and sometimes density fluctuations. These in turn can lead to increased drag forces, excessive noise and vibrations problems in structures. It is therefore essential to understand the cavity-flow physics and to be able to model, analyze and predict the outcome of such flows with acceptable accuracy if the adverse effects are to be controlled and minimized. Although many studies have been conducted about the cavity flows most of them have mainly focused on supersonic and compressible flows because of their relevance to aeronautical applications. However, much less attention has been given to very low Mach number cavity flows that are encountered in various grounds, industrial and environmental applications so far. There have been some studies dealing with incompressible cavity flow, but these were mainly focused on flow inside or around two-dimensional cavities and there have been very few investigations on flow inside a three-dimensional cavity. Therefore, there is a real need for better understanding of the three-dimensional effects in cavity flows at very low Reynolds numbers. The main purpose of this work is to study the three-dimensional effects on the characteristics of the cavity flow at very low Mach numbers and to improve the understanding of this type of flow. Therefore this study presents a numerical study into the problem of incompressible laminar flow passing a two and three-dimensional rectangular cavity with a view to understanding the complex nature of the flow and the three-dimensional structure of the cavity. The study is based on the solution of the unsteady, three-dimensional, incompressible Navier-Stokes equations by using finite volume method and Large Eddy Simulation approach. A cavity with length to depth ratio of 4 under an incoming laminar boundary layer is investigated for Re is equal to 4000 (based on cavity depth and free stream velocity). To validate the used computational procedure and simulations, the study of Özsoy et al. (2005) on two dimensional cavities under laminar incoming flow with L/h ratio of 4 is used.  After this validation step, three-dimensional flow features of incompressible cavity flows with an incoming laminar boundary layer is investigated. The influence of the recirculating flow inside the cavity on the separated shear layer, the nature of the interactions between the large-scale eddies and the trailing edge corner and the dynamic behavior of the vortex structures occurring in a cavity are studied. The results obtained from computations show that the flow field inside the cavity has a three dimensional structure, even in two-dimensional cavity geometries including vortex shedding mechanism, stretching, wall vortex interaction like clipping or partially escape and so on. Time-averaged parameters in 3D analyses of 3D cavity reveal that the characteristics of the flow change significantly due to the side wall effects.  As expected the wall effects are stronger at locations closer to the wall.   Another important result from 3D analyses is that if the instantaneous flow field is considered, flow structures are quite different at different stations and highly time dependent. . When 3D flow characteristics are compared to those of 2D it is found that the mean flow features are almost the same for 3D and 2D only at the middle of the cavity. However, this is not the case when the results are compared outside this plane.  The 2D and 3D results are significantly different at planes away from the symmetry plane. Although the mean flow quantities are about the same for 2D and 3D in the middle plane, turbulence behavior is quite different. It is believed that the validated computational procedure presented in this study for the analyses of flow over cavities can be used to determine the forces acting to the structures due cavities and this information can also be used for design purposes.  Also, the validated computational procedure in this work can help future researchers to perform similar analyses for various kinds of cavities with high level of confidence and to optimize the geometry of the cavities for minimum drag, noise and vibration. Keywords: Cavity flow, vortex, LES, laminar flow.

    Properties of Command Constructions in TİD

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    This paper focuses on the properties of command constructions in Turkish Sign Language (TİD). The nature and function of manual signs and nonmanual markers in command constructions in TİD are investigated to determine their prosodic, morphological, morphophonological, and syntactic properties. We show that TİD does not utilize any of the properties reported in the literature as an obligatory marker of commands in some spoken and sign languages. The only salient marker of commands we have identified is a nonmanual marker: (forward/sideward) head tilt

    Turkish-German heritage speakers’ predictive use of case: webcam-based vs. in-lab eye-tracking

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    Recently, Özge et al. have argued that Turkish and German monolingual 4-year- old children can interpret case-marking predictively disregarding word order. Heritage speakers (HSs) acquire a heritage language at home and a majority societal language which usually becomes dominant after school enrollment. Our study directly compares two elicitation modes: in-lab and (remote) webcam- based eye-tracking data collection. We test the extent to which in-lab eects can be replicated in webcam-based eye-tracking using the exact same design. Previous research indicates that Turkish HSs vary more in the comprehension and production of case-marking compared to monolinguals. Data from 49 participants–22 Turkishmonolinguals and 27 HSs–were analyzed using a binomial generalized linear mixed-eects regression model. In the Accusative condition, participants looked for the suitable Agent before it is appeared in speech. In the Nominative condition, participants looked for the suitable Patient before it is appeared in speech. HSs were able to usemorphosyntactic cues on NP1 to predict the thematic role of NP2. This study supports views in which core grammatical features of languages, such as case, remain robust in HSs, in line with the Interface Hypothesis. We were able to replicate the eect of the predictive use of case in monolinguals using webcam-based eye-tracking, but the replication with heritage speakers was not successful due to variability in data collection contexts. A by- participant analysis of the results revealed individual variation in that there were some speakers who do not use case-marking predictively in the same way asmost monolinguals and most HSs do. These findings suggest that the predictive use of case in heritage speakers is influenced by dierent factors, whichmay dier across individuals and aect their language abilities. We argue that HSs should be placed on a native-speaker continuum to explain variability in language outcomes

    The biological activities and phytochemical content of Ferulago humulis Boiss.

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    Ferulago humulis Boiss. is an endemic species growing in Turkey. The aim of the study was to compare in vitro antioxidant and antimicrobial activities of the aerial parts (HFH) and rhizomes (RFH) of F. humulis. According to the results of antimicrobial and antioxidant activities of the extracts obtained from different parts of the plant, their phytochemical contents were evaluated. Petroleum ether (HFH-PE; RFH-PE), dichloromethane (HFH-DM; RFH-DM) and methanol (HFH-ME; RFH-ME) extracts from aerial parts (HFH) and rhizomes (RFH) of F. humulis were obtained for antimicrobial activity and examined by the agar hole diffusion and microdilution methods. Chromatographic and spectroscopic (1H NMR, LS-MS and UV) techniques were used for the isolation of coumarin compounds from petroleum ether (RFH-PE) and dichloromethane (RFH-DM) extracts. Furthermore, antioxidant activity were assayed by the 4 different methods in methanol extracts (HFH-ME; RFH-ME). HFH-PE (MIC=6.25 mg/mL), RFH-PE (MIC=12.5 mg/mL) and RFH-DM (MIC=11 mg/mL) extracts against Staphylococcus aureus, and RFH-PE (MIC= 3.125 mg/mL), HFH-PE (MIC=6.25 mg/mL) extracts showed antimicrobial activity against S. epidermidis. HFH-PE (MIC=1.56 mg/mL), RFH-PE (MIC= 6.25 mg/mL) extracts exhibited antifungal activity against Candida tropicalis. From the rhizomes of F. humulis isoimperatorin, bergapten, oxypeucedanin, marmesin senecioate and oxypeucedanin hydrate known as furanocoumarins derivatives were isolated

    The biological activities and phytochemical content of Ferulago humulis Boiss.

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    728-735Ferulago humulis Boiss. is an endemic species growing in Turkey. The aim of the study was to compare in vitro antioxidant and antimicrobial activities of the aerial parts (HFH) and rhizomes (RFH) of F. humulis. According to the results of antimicrobial and antioxidant activities of the extracts obtained from different parts of the plant, their phytochemical contents were evaluated. Petroleum ether (HFH-PE; RFH-PE), dichloromethane (HFH-DM; RFH-DM) and methanol (HFH-ME; RFH-ME) extracts from aerial parts (HFH) and rhizomes (RFH) of F. humulis were obtained for antimicrobial activity and examined by the agar hole diffusion and microdilution methods. Chromatographic and spectroscopic (1H NMR, LS-MS and UV) techniques were used for the isolation of coumarin compounds from petroleum ether (RFH-PE) and dichloromethane (RFH-DM) extracts. Furthermore, antioxidant activity were assayed by the 4 different methods in methanol extracts (HFH-ME; RFH-ME). HFH-PE (MIC=6.25 mg/mL), RFH-PE (MIC=12.5 mg/mL) and RFH-DM (MIC=11 mg/mL) extracts against Staphylococcus aureus, and RFH-PE (MIC= 3.125 mg/mL), HFH-PE (MIC=6.25 mg/mL) extracts showed antimicrobial activity against S. epidermidis. HFH-PE (MIC=1.56 mg/mL), RFH-PE (MIC= 6.25 mg/mL) extracts exhibited antifungal activity against Candida tropicalis. From the rhizomes of F. humulis isoimperatorin, bergapten, oxypeucedanin, marmesin senecioate and oxypeucedanin hydrate known as furanocoumarins derivatives were isolated
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