Design, synthesis and characterization of bioinspired nanomaterials for engineering and biomedicine

Ankara : The Materials Science and Nanotechnology Program and the Graduate School of Engineering and Science of Bilkent University, 2014.Thesis (Ph. D.) -- Bilkent University, 2014.Includes bibliographical references leaves 227-247.Nature is an inspirational school for materials scientists. Natural selection process puts a massive pressure on biological organisms giving rise to effective strategies for fabricating materials, which generally outperform their man-made counterparts. Mimicking physical and chemical features of biological materials can greatly aid in overcoming existing design constraints of engineering and medicine. In this dissertation, a reductionist, bottom-up approach is demonstrated to recapitulate biological functionalities in fully-synthetic hybrid constructs. For material design, the potential of short, rationally-designed peptides for programmed organization into nanostructured materials is explored. The resulting nano-ordered materials exhibit multifunctional and adaptive properties, which can be tailored by the information within monomeric peptide sequences as well as the emerging properties upon their self-assembly. In light of these, design, synthesis and characterization of the prototypes of nanostructured functional materials are described in the context of regenerative medicine and biomineralization.Ceylan, HakanPh.D

Investigating the Extractive Summarization of Literary Novels

Abstract Due to the vast amount of information we are faced with, summarization has become a critical necessity of everyday human life. Given that a large fraction of the electronic documents available online and elsewhere consist of short texts such as Web pages, news articles, scientific reports, and others, the focus of natural language processing techniques to date has been on the automation of methods targeting short documents. We are witnessing however a change: an increasingly larger number of books become available in electronic format. This means that the need for language processing techniques able to handle very large documents such as books is becoming increasingly important. This thesis addresses the problem of summarization of novels, which are long and complex literary narratives. While there is a significant body of research that has been carried out on the task of automatic text summarization, most of this work has been concerned with the summarization of short documents, with a particular focus on news stories. However, novels are different in both length and genre, and consequently different summarization techniques are required. This thesis attempts to close this gap by analyzing a new domain for summarization, and by building unsupervised and supervised systems that effectively take into account the properties of long documents, and outperform the traditional extractive summarization systems typically addressing news genre

Estimation of Compressive Strength of Waste Andesite Powder-Added Concrete Using an Artifical Neural Network

In this study, the effects of using andesite powder wastes-produced from natural stone factories as mineral additives in concrete manufacturing-on the compressive strength of concrete were modeled using an Artificial Neural Network (ANN). To achieve this, cement mixtures were produced by using waste andesite powder (WAP) mixture at ratios of 0% (control), 10%, 15% and 20%. The effects of curing time were investigated by preparing specimens at 28 and 90 days. The training set was formed by using cement and the specified WAP mixtures and curing time parameters. It was observed that the results obtained from the training ANNs were consistent with the experimental data

Bütünleşik tedarik zinciri çizelgeleme modelleri: Bir literatür taraması

Research on integration of supply chain and scheduling is relatively recent, and number of studies on this topic is increasing. This study provides a comprehensive literature survey about Integrated Supply Chain Scheduling (ISCS) models to help identify deficiencies in this area. For this purpose, it is thought that this study will contribute in terms of guiding researchers working in this field. In this study, existing literature on ISCS problems are reviewed and summarized by introducing the new classification scheme. The studies were categorized by considering the features such as the number of customers (single or multiple), product lifespan (limited or unlimited), order sizes (equal or general), vehicle characteristics (limited/sufficient and homogeneous/heterogeneous), machine configurations and number of objective function (single or multi objective). In addition, properties of mathematical models applied for problems and solution approaches are also discussed.Bütünleşik Tedarik Zinciri Çizelgeleme (BTZÇ) üzerine yapılan araştırmalar nispeten yenidir ve bu konu üzerine yapılan çalışma sayısı artmaktadır. Bu çalışma, bu alandaki eksiklikleri tespit etmeye yardımcı olmak için BTZÇ modelleri hakkında kapsamlı bir literatür araştırması sunmaktadır. Bu amaçla, bu çalışmanın bu alanda çalışan araştırmacılara rehberlik etmesi açısından katkı sağlayacağı düşünülmektedir. Bu çalışmada, BTZÇ problemleri üzerine mevcut literatür gözden geçirilmiş ve yeni sınıflandırma şeması tanıtılarak çalışmalar özetlenmiştir. Çalışmalar; tek veya çoklu müşteri sayısı, sipariş büyüklüğü tipi (eşit veya genel), ürün ömrü (sınırlı veya sınırsız), araç karakteristikleri (sınırlı/yeterli ve homojen/heterojen), makine konfigürasyonları ve amaç fonksiyonu sayısı (tek veya çok amaçlı) gibi özellikler dikkate alınarak kategorize edildi. Ayrıca problemler için uygulanan matematiksel modellerin özellikleri ve çözüm yaklaşımları da tartışılmıştır

Three-factor asset pricing model and portfolio holdings of foreign investors: evidence from an emerging market – Borsa Istanbul

This article contributes to the asset pricing literature by offering an alternative missing factor: the excess holdings of foreign investors. To incorporate this factor, we mimic the portfolio of foreign investors in Borsa Istanbul (BIST) with respect to portfolio preferences (foreign ownership) using the Fama and French’s three-factor model. Our findings suggest that market factor, size, and book-to-market (B/M) variables are still statistically significant and Jensen’s alpha is still not significant, and we obtain a statistically significant negative relationship between the excess return of foreign investors’ ownership and the return variation of a given portfolio

The comparison of using andesite waste powder and fly ash in concrete

Türkiye’de andezit taşı inşaat mühendisliği ve mimari uygulamalarda yaygın olarak kullanılmaktadır. Andezit taşının madencilik yöntemleriyle üretimi, kesilmesi ve cilalanması büyük miktarda atık oluşumuna neden olmaktadır. Bunların bir kısmı ocak ve fabrikadan çıkan iri parçalı atıklardır. Bir kısmı ise fabrikada kesim sırasında çıkan toz atıklardır. Bu atıklar değerlendirilmeden atılmaktadır. Andezit temel bileşen olarak SiO2 içerir, bu yüzden andezit tozları puzolanik özellik gösterir ve betonda mineral katkı olarak kullanılabilir. Bu çalışmada andezit atık tozlarının betonda mineral katkı olarak kullanılması, F sınıfı uçucu küller ile karşılaştırılmıştır. Mineral katkıların farklı yer değiştirme seviyelerindeki durumunu belirlemek için, farklı çimento dozajlarında beton örnekleri hazırlanarak 28 ve 90 günde beton basınç dayanımları test edilmiştir. C40/50 dayanım sınıfı için, 28 ve 90 günlük kür yaşlarında atık andezit tozlarının en uygun yer değiştirme oranı %10 olarak belirlenmiştir. Çalışmadan elde edilen bulgulara göre atık andezit tozlarının uçucu küller gibi betonda mineral katkı olarak kullanılabileceğini göstermektedir. Mineral katkı olarak en ideal yer değiştirme oranlarında andezit kullanımı durumunda, C40/50 betonunda yaklaşık 20 kg, C55/67 betonunda 46 kg, C70/85 betonunda 52 kg çimento tasarrufu sağlanabilir.Andesite stone is widely used in civil engineering and architectural applications in Turkey. The production, cutting and polishing of the andesite stone by mining methods causes a large amount of waste. Some of them are big particular waste that is taken off pit and factories. And the others are powder waste derived during cutting in factories. These are wasted and not reclaimed. Andesite contains SiO2 as the main component. Therefore, andesite may have pozzolanicity and thus may be used as mineral additive in concrete. In this study the usage of andesite waste powder as mineral additive in concrete is compared with F type fly ashes. In order to estimate the status of mineral additives in various replacement levels; the 28 and 90 days compressive strengths of concrete specimens were tested by preparing concrete specimens in different cement dosages. For C40/50 strength class, the optimum replacement rate of andesite waste powder was determined as 10% at curing ages of 28 and 90 days. The results of this study show that andesite waste powder can be used as mineral additive in concrete such as fly ash. The usage of andesite waste powder as a mineral additive at the optimal replacement ratios can achieve savings of, 20 kg cement for C40/50, 46 kg of cement for C55/67, and 52 kg of cement for C70/85

PHOTOGRAMMETRIC APPROACH IN DETERMINING BEAM-COLUMN CONNECTION DEFORMATIONS

In accordance with the advances in technology, displacement calculation techniquesare ever developing. Photogrammetry has become preferable in some newdisciplines with the advances in the image processing methods. In this study, theauthors have used two different measurement techniques to determine the angles ofrotation in beam-column connections that are subjected to reversible cyclic loading.The first of these is the method that is widely used, the conventional method instructural mechanics experiments, where Linear Variable Differential Transformers(LVDTs) are utilized; and the second is the photogrammetric measurementtechnique. The rotation angles were determined using these techniques in a total often steel beam-column connection experiments. After discussing the test proceduresof the aforementioned methods, the results were presented. It was observed that therotation angles measured by each method were very close to each other. It wasconcluded that the photogrammetric measurement technique could be used as analternative to conventional methods, where electronic LVDTs are used

Explorations in Automatic Book Summarization

This paper discusses explorations in automatic book summarization

The Decomposition of Human-Written Book Summaries

In this paper, the authors evaluate the extent to which human-written book summaries can be obtained through cut-and-paste operations from the original book. The authors analyze the effect of the parameters involved in the decomposition algorithm, and highlight the distinctions in coverage obtained for different summary types

Şırnak kömür madeni atık şeyl yığınlarının statik analizleri

Şırnak kömür madeni atık şeyl yığınları şehrin daha düzlük yerleşme alanının içersinde kalmaktadır. Çevreye uygun olarak atık seyl yığınlarının tasarımı ve reklamasyonu gerekmektedir. Bu nedenle şu andaki yığınların jeoteknik özellikleri, statik nitelikleri bu çalışmada ele alınmaktadır. Katı atık düzenli depolama sahalarının deprem, sel veya diğer statik ve dinamik tehlikelere göre kararlılık analizi işletmede gerekmektedir. Bu nedenle Şırnak ilinin civarındaki kömür maden atık yığınlarının çevreye duyarlı olarak değerlendirilmesi gerekir. Yığınların neden olabileceği potansiyel ve aktif heyelan sahaları incelenmiş, GEO 5 programı ile jeoteknik açıdan irdelemesi ve duraylılık analizleri yapılmıştır. S1, S2, S3 ve S4 no’lu yamaçların 1/1000 ölçekli topoğrafik haritaları arazi çalışmalarıyla hazırlanmış ve yığının yapısal kesitleri çıkarılmıştır. Yığından alınan zemin örnekleri üzerinde yapılan laboratuar deneyleri ile yamaç molozunun fiziksel ve mekanik özellikleri; Efektif içsel sürtünme açısı (φ′°) 17°-22.5°, Efektif kohezyonu (c′) 0,5-1,8 kg/cm2, maksimum kuru birim hacim ağırlık 1.87-2.05 g/cm3 , doygun birim hacim ağırlık 1.97-2.24 g/cm3, Tane birim hacim ağırlığı (γs) 2.47-2.60 g/cm3, Permeabilite katsayısı 4x10-4- 5.5x10-4cm/s, olarak belirlenmiş ve ayrıca tane dağılım testleri yapılmıştır. Yamaçların hazırlanan kesitlerinde, GEO 5 programında olası deneme kayma yüzeyleri irdelenmiştir. Yığın malzemenin belirlenen jeoteknik özellikleri de kullanılarak GEO5 programı ile Fellenius, Spencer, Bishop, Janbu ve Hoek-Bray yöntemleri aracılığı ile güvenlik katsayıları belirlenmiş ve hesaplanan değerlere göre S3 ve S4 no’lu yamaçların duraylı oldukları S1 ve S2 no’lu yamacların ise duraysız durumda olduğu tespit edilmiştir.Earth movements in the highly populated urban residential areas, can lead to high loss of life and greatly damage to buildings and other property forms at an important geological risk. For this reason, active and passive landslide areas should be identified, required measures to be taken of these areas must be determined by performing geotechnical investigations and stability analyses. Also landslide in making decisions on land development fields, especially in high-risk areas should not be allowed in urban construction. For this reason, the various districts of the province of Sirnak, active and potential landslide areas, mining and geotechnical stability analyses were conducted. The drilling and laboratory geotechnical engineering properties of materials are determined by experiments. S1, S2, S3 and S4 hillsides to develop landslide slopes 1/1000 scale topographic maps and geological field studies prepared by processing units on the map the geological cross-sections were prepared. By laboratory experiments carried out on soil samples taken from fields of physical and mechanical properties of slope dump; effective angle of internal friction (φ '°) 17° -22.5°, effective cohesion (c') 0,5-1,8 kg/cm2 , the maximum dry unit weight 1.87 -2.05 g/cm3, the saturated unit weight 1.87-2.24 g/cm3 dry unit weight, unit weight (γs) 2.47-2.60 g / cm3 , permeability coefficient of 1x10-4- 6.5x10-4cm / s. The particle distribution were determined. Geological sections were prepared, according to slopes, the geotechnical properties of the material is evaluated by the trial slip surfaces using the Fellenius, Bishop, and Hoek-Bray methods, Janbu method. The safety factors were determined and calculated according to the values the S1, S2 slopes were unstable hillsides and for S3and S4 slopes the conditions were found to show stable close