617 research outputs found
Effects of Mold Cavity Geometry on Flow Rate and Mechanical Properties in Al-Si-Mg Alloy
No full textIn this study, the effects of the oxide films formed by using different mold cavity geometries on the mechanical properties of the parts were investigated. The casting process was carried out using the same runner system with different mold geometries. The effect of liquid metal flow rate on bifilm formation and the mechanical properties of the cast material were examined. Eventually, oxide bifilms formed in the mold cavity when the flow rate is low (caused by folding). These oxide bifilms negatively affect the mechanical properties as much as the oxide bifilms formed in the runner system. When real-time liquid metal flow rates are examined in different casting cavities, flow irregularities such as turbulence, folding, and splashing were developed differently in the flow rate of the liquid metal. It was determined that the stability in the flow rate of the liquid metal directly affects the mechanical strength
FIGURE 2 a, f in A new hybrid of Origanum (Lamiaceae) from the Aegean Island of Karpathos (Dodecanese, Greece): Origanum × karpathicum
No full textFIGURE 2 a, f- Origanum onites, b-d, g- O. × karpathicum, e, h-O. vetteriPublished as part of Cattaneo, Cristina, Dimarchou, Theocharoula, Özcan, Taner & Dirmenci, Tuncay, 2022, A new hybrid of Origanum (Lamiaceae) from the Aegean Island of Karpathos (Dodecanese, Greece): Origanum × karpathicum, pp. 43-56 in Phytotaxa 560 (1) on page 46, DOI: 10.11646/phytotaxa.560.1.3, http://zenodo.org/record/703119
Welfare and research and development incentive effects of uniform and differential pricing schemes
No full textThis paper is about the application of optimization methods to the analysis of three pricing schemes adopted by one manufacturer in a two-country model of production and trade. The analysis focuses on pricing schemes—one uniform pricing scheme, and two differential pricing schemes—for which there is no competition coming from the so-called parallel trade. This term denotes the practice of buying a patented product like a medicine in one market at one price, then re-selling it in a second so-called gray market at a higher price, on a parallel distribution chain where it competes with the official distribution chain. The adoption of pricing schemes under which parallel trade does not arise can prevent the occurrence of its well-documented negative effects. In the work, a comparison of the optimal solutions to the optimization problems modeling the three pricing schemes is performed. More specifically, conditions are found under which the two differential pricing schemes are more desirable from several points of view (e.g., incentive for the manufacturer to do Research and Development, product accessibility, global welfare) than the uniform pricing scheme. In particular, we prove that, compared to the uniform pricing scheme, the two differential pricing schemes increase the incentive for the manufacturer to invest in Research and Development. We also prove that they serve both countries under a larger range of values for the relative market size, making the product more accessible to consumers in the lower price country. Moreover, we provide a sufficient condition under which price discrimination is more efficient from a global welfare perspective than uniform pricing. The analysis applies in particular to the case of the European Single Market for medicines. Compared to other studies, our work takes into account also the possible presence in all the optimization problems of a positive constant marginal cost of production, showing that it can have non-negligible effects on the results of the analysis. As an important contribution, indeed, our analysis clarifies the conditions—which have been overlooked in the literature about the mechanisms adopted to prevent parallel trade occurrence—that allow/do not allow one to neglect the presence of this factor. Such conditions are related, e.g., to the comparison between the positive constant marginal cost of production, the parallel trade cost per-unit, and the maximal price that can be effectively charged to the consumers in the lower price country.Publisher versio
Two-dimensional natural convection in a porous triangular enclosure with a square body
No full textA two-dimensional numerical solution for steady-state buoyancy induced convection in a right-triangular enclosure with a square body is obtained using finite difference technique. The solid body is located far from the origin with the distance of 0.3 in both directions. It is considered that the temperature of the bottom wall of triangular enclosure is higher than that of inclined wall while the vertical wall is insulated. To obtain the effects of the presence of a square body on heat transfer and fluid flow inside the enclosure, four different temperature boundary conditions were applied for the body as heated, cooled, neutral and adiabatic at different Ra numbers. It is observed that fluid flow and temperature fields strongly depend on thermal boundary conditions of the body. © 2006 Elsevier Ltd. All rights reserved
Practical least privilege for cross-origin interactions on mobile operating systems
No full textMobile operating systems (i.e., mobile platforms) favor flexibility and re-usability as design principles and provide mobile applications with channels for establishing cross-origin interactions in an effort to realize these principles. Under this cross-origin scheme, applications accomplish tasks collaboratively with other principals, such as the web, other applications, and system components, by relying on them for certain functionality and data, considerably saving platform resources as well as the programming efforts of application developers. While clearly helping to provide a captivating mobile experience, this rich set of interactions within mobile platforms unfortunately also create significant attack vectors and pose notable security risks that need to be carefully taken into account to ensure the security of the platform.
In this thesis, we focus on the security of cross-origin interaction channels on mobile operating systems. We choose Android as a use case due to its popularity and open source and show that cross-origin interactions constitute a significant impediment to establishing least privilege on Android. More specifically, we show that there are severe issues in the security mechanisms that are put in place by Android or even a lack of adequate mechanisms to protect these interactions, which enable adversaries to stealthily obtain sensitive user data, high-risk platform resources, and application functionalities. We demonstrate the severity of these vulnerabilities by our measurement studies and showcases of exploits on popular real-world applications with millions of downloads on Google Play and show that a majority of Android users are rendered vulnerable due to these critical issues. As a remedy, we propose practical designs that strive to make Android more robust and secure by addressing the problems with cross-origin channels in a systematic, effective, and efficient manner.
In particular, we show that mobile applications that utilize embedded web browsers are under the risk of inadvertently exposing critical resources to untrusted web domains and we propose a systematic and practical access control mechanism to address this issue. Additionally, we disclose serious vulnerabilities in Android's permission framework that put inter-process communication and platform resources at severe risk and we redesign Android permissions to systematically resolve the issues. Finally, we present new attacks on Android's runtime permissions which proves that this new permission model cannot satisfy its key security guarantees due to design issues and vulnerabilities, jeopardizing the security of platform resources. We discuss the current approach taken by Android to mitigate these issues and demonstrate how this mechanism, although seemingly an ideal solution, is still intrinsically broken due to the existing vulnerabilities that we discovered.
All in all, this thesis aims to identify issues that threaten least privilege on mobile platforms and strives to provide practical mitigation solutions to resolve such issues. Our work has influenced the design and implementation of some of the critical security mechanisms in Android and has consequently led to changes in the official Android releases by Google. Even though we used Android as a use case here, the issues we disclosed in this thesis can also be encountered on other mobile platforms that utilize cross-origin interactions and our methodologies and designs go beyond Android to the design of mobile operating systems more generally.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-08-01The student, Guliz Tuncay, accepted the attached license on 2019-07-10 at 14:16.The student, Guliz Tuncay, submitted this Dissertation for approval on 2019-07-10 at 14:33.This Dissertation was approved for publication on 2019-07-10 at 16:04.DSpace SAF Submission Ingestion Package generated from Vireo submission #14248 on 2019-11-26 at 14:03:41Made available in DSpace on 2019-11-26T20:59:44Z (GMT). No. of bitstreams: 5
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FIGURE 1. A in Three new records for the flora of Turkey: Campanula lyrata subsp. icarica (Campanulaceae), Erysimum aureum (Brassicaceae) and Stachys benthamiana (Lamiaceae)
No full textFIGURE 1. A: Distribution map of Campanula lyrata subsp. icarica (red stars), Erysimum aureum (yellow squares) and Stachys benthamiana (bluish circle) in Turkey; B–I: images from the new Turkish populations: B, C, D—C. lyrata subsp. icarica; E, F, G—E. aureum; H, I—S. benthamiana.Published as part of Özdöl, Tuğkan, Güner, Özal, Sefali, Abdurrahman, Akçiçek, Ekrem, Dirmenci, Tuncay & Yildirim, Hasan, 2022, Three new records for the flora of Turkey: Campanula lyrata subsp. icarica (Campanulaceae), Erysimum aureum (Brassicaceae) and Stachys benthamiana (Lamiaceae), pp. 147-150 in Phytotaxa 531 (2) on page 148, DOI: 10.11646/phytotaxa.531.2.8, http://zenodo.org/record/586935
Synthesis, Crystal Structure and Spectroscopic Studies of 2-{(E)-[2-Hydroxyphenyl)imino]methyl} Phenol Schiff Base Molecule
No full textWOS: 000268300800012A new Schiff-base complex 2-{(E)-[2-hydroxyphenyl)imino]methyl}phenol has been synthesized and characterized by elemental analyses, UV-VIS and IR spectroscopy and single crystal X-ray determination. The structure comprises two independent and similar molecules. The two independent molecules in the asymmetric unit are hydrogen bonded and have different conformations. In each molecule, C13H11NO2, adopt an E configuration about the azomethine C-N double bond. The complex crystallized in the triclinic space group P-1. Two benzene rings and azomethine group are practically coplanar, as a result of intramolecular hydrogen bonds involving the hydroxy O atom and azomethine N atom. Also hydroxy group of the molecule is the presence intermolecular O-H center dot center dot center dot O hydrogen bonds with the hydroxy group of the other molecule.University Research Fund [F. 279]The authors thank to acknowledge the Faculty of Arts and Sciences, Ondokuz Mayis University, Turkey, for use of the Stoe IPDS-2 diffractometer purchased under grant F. 279 of the University Research Fund
Fatigue Crack Growth Under Variable Amplitude Loading Through XFEM
No full textAbstractPredicting fatigue crack growth (FCG) rate and path under variable amplitude loading (VAL) is a crucial issue in damage tolerant design commonly used in aerospace industry. The aim of the current study is to predict FCG life under VAL through Extended Finite Element Method (XFEM) and to explicitly illustrate both FCG life and crack propagation. For this purpose an algorithm is developed and integrated in ABAQUS software to analyze 3D crack propagation under VAL using Modified Generalized Willen-borg (MGW) retardation model. The results are compared with NASGRO crack propagation software and experimental FCG test data on 7075-T6 aluminum alloy under various over load (OL) and over load-under load (OL-UL) conditions which exhibit a good agreement
TGFBI Geninde Genom Düzenleme Tekniği ile Oluşturulan Varyasyonların Zebra Balığı Korneasındaki Fenotipik Etkilerinin İncelenmesi
No full textYAYLACIOĞLU TUNCAY F. Evaluation of Phenotypic Effects of Genome Editing-mediated TGFBI Variation on Zebrafish Cornea. Hacettepe University, Graduate School of Health Sciences, Medical Biology PhD Thesis, Ankara, 2019. TGFBI-related corneal dystrophies are hereditary disorders characterized by accumulation of the abnormal protein product of TGFBI gene in the hyaline or amyloid form due to missense mutations of this gene. This gene exists in the zebrafish genome without duplication and its protein product has 65% homology to its human ortholoque. Protein product of tgfbi (TGFBIp) was shown in the cornea of zebrafish. Mutations of this gene that effect the arginine residue on the 124th position of TGFBIp were reported as one of the hot spots for this group of corneal dystrophies. This argininine residue was also conserved in zebrafish. According to these data; in this study we aimed to make an in frame change in the region that codes the 124th amino acid residue of tgfbi in the zebrafish genome by using TALEN or CRISPR/Cas9. Finally, we achieved indel variation at the target sequence that resulted in p. Ser115_Arg117delinsLeu (c. 347_353delinsT) by nonhomology mediated repair. This variation could mimic the disease process in the zebrafish cornea. The 3 months old zebrafish eyes were examined histopathologically under the light microscope but no amiloid or hyaline deposits could be detected with hematoxylen-eosin, masson-trichrome and congo red staining. Thus, this study is the first in literature that succeeded to make an in frame variation effecting the hot spot arginine residue in tgfbi protein and further studies could detect phenotypical changes in older zebrafish that could mimic the TGFBI-related corneal dystrophies and help to reveal the disease pathogenesis.YAYLACIOĞLU TUNCAY F. TGFBI Geninde Genom Düzenleme Tekniği ile Oluşturulan Varyasyonların Zebra Balığı Korneasındaki Fenotipik Etkilerinin İncelenmesi. Hacettepe Üniversitesi, Sağlık Bilimleri Enstitüsü, Tıbbi Biyoloji Doktora Tezi, Ankara, 2019. TGFBI-ilişkili kornea distrofileri, bu gende meydana gelen yanlış anlamlı mutasyonlar sonucu oluşan protein ürününün amiloid ya da hiyalin yapıda korneada birikmesiyle ortaya çıkan kalıtsal bir hastalık grubudur. TGFBI geni zebra balığında tek kopya olarak bulunmakta olup protein dizisi insandaki ortoloğu ile %65 homolojiye sahiptir. Bu genin protein ürünü (TGFBIp) zebra balığı korneasında gösterilmiştir. TGFBI’da 124. amino asit olan arjinini kodlayan kodon bu hastalık grubunda en sık bildirilen mutasyon bölgelerinden biridir. 124. arjinin amino asidi zebra balığında da korunmuştur. Bu verilerden yola çıkarak tez kapsamında zebra balığında tgfbi’de hedefteki arjinin rezidüsünü kodlayan bölgede TALEN ya da CRISPR/Cas9 genom düzenleme araçlarını kullanarak in frame değişiklik yapmayı amaçladık. Tgfbi’de hedef bölgedeki değişiklik homolog olmayan uç birleştirme tamir mekanizması ile oluşturulmuş olup hedef arjinin amino asidini ortadan kaldıracak şekilde p. Ser115_Arg117delinsLeu (c. 347_353delinsT) varyasyonu elde edilmiştir. Bu varyasyon hastalığı zebra balığında taklit etme potansiyeline sahiptir. Varyasyonu heterozigot olarak taşıyan 3 aylık zebra balıklarının gözlerinde ışık mikroskobu ile yapılan histolojik incelemelerde hematoksilen eosin, masson trikrom ve kongo kırmızısı ile boyamada hiyalin veya amiloid birikim saptanmamıştır. Bu tez çalışması, tgfbi geninde kornea distrofilerine neden olan 124. arjinin amino asidini zebra balığı genomunda ortadan kaldırarak in frame indel oluşturan ilk çalışmadır. Bu varyasyonu taşıyan zebra balıklarının daha ileri yaşlarda incelenmesi sonucu fenotipik değişiklikler tespit edilerek TGFBI-ilişkili kornea distrofilerinin modellenmesi ve hastalığın patogenezinin ortaya konulması mümkün olabilecektir
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