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An Innovative Showcase of Similarity Methods for Accelerated Turbine Design Processes and Cost-Effective Solutions
No full textThis study aims to design a containerized Francis-type turbine for installation on drinking water pipelines equipped with pressure-reducing equipment, enabling energy recovery from untapped hydraulic resources. The turbine, designed to operate unmanned and housed within a container, represents an innovative approach to harnessing residual energy in drinking water pipelines. The research methodology leverages similarity laws derived from a previously developed high-efficiency turbine facility as a foundation for the preliminary design. This approach diverges from conventional turbine design methods, offering significant time and cost efficiencies. It should be noted that similarity laws were used only for the preliminary dimensioning of the scale turbine. Following this initial design, design optimizations were carried out based on CFD, focusing on components such as the runner, to enhance performance and achieve the required power output without cavitation at the specified flow rate and head. The results demonstrate that the application of similarity laws expedites the design process while maintaining high efficiency, effectively addressing the unique constraints of the operational environment. Additionally, the study provides a comprehensive analysis of the advantages and limitations of employing similarity in turbine design. In conclusion, this research not only exemplifies a novel turbine design methodology that ensures operational similarity but also serves as a practical guide for reducing costs and design timelines in small hydropower applications.This now clearly states that similarity was used for the preliminary dimensioning, followed by optimization based on CFD.THE CFD studies within the scope of this research were conducted using the infrastructure of the TOBB ETU Hydropower Turbine Design and Test Center.Trkiye Bilimsel ve Teknolojik Arascedil;timath;rma Kurumu; TOBB ETU Hydropower Turbine Design and Test Cente
Electroweak, QCD and Flavour Physics Studies With ATLAS Data From Run 2 of the LHC
No full textRedlinger, George/0000-0002-6437-9991; Meloni, Federico/0000-0001-7075-2214; Beau, Tristan/0000-0002-2022-2140; Butterworth, Jonathan/0000-0002-5905-5394; Kowalewski, Robert/0000-0002-7314-0990; Carmignani, Joseph (Joe)/0000-0002-1705-1061; Bouhova-Thacker, Evelina/0000-0002-5103-1558; Azuelos, Georges/0000-0003-4241-022X; Cheong, Sanha/0000-0002-2797-6383; Mckee, Shawn/0000-0002-4551-4502; Mcpherson, Robert/0000-0001-9211-7019; Nikolopoulos, Konstantinos/0000-0002-3048-489X; Kirk, Julie/0000-0001-8096-7577; Jia, Jiangyong/0000-0002-5725-3397; De La Torre Perez, Hector/0000-0002-4516-5269; Morii, Masahiro/0000-0001-9324-057X; Kretzschmar, Jan/0000-0002-8515-1355; Schultz-Coulon, Hans-Christian/0000-0002-0860-7240; Pettee, Mariel/0000-0001-9208-3218; Fox, Harald/0000-0003-3089-6090; Schmitt, Stefan/0000-0001-8387-1853; Smirnova, Oxana/0000-0003-2517-531X; Vincter, Manuella/0000-0002-5338-8972; Bella, Gideon/0000-0002-4009-0990; Terzo, Stefano/0000-0003-3388-3906; Tishelman-Charny, Abraham/0000-0002-7332-5098; Islam, Wasikul/0000-0002-5624-5934; Winter, Benedict Tobias/0000-0001-9606-7688; Keeler, Richard/0000-0002-0510-4189; Lloyd, Stephen/0000-0002-5073-2264; Stark, Giordon/0000-0001-6616-3433; Grinstein, Sebastian/0000-0002-6460-8694; Konstantinidis, Nikolaos/0000-0002-4140-6360;A summary of precision measurements sensitive to electroweak, QCD and quark-flavour effects performed by the ATLAS Collaboration at the Large Hadron Collider is reported. The measurements are predominantly performed on proton-proton (pp) collision data recorded at a centre-of-mass energy of 13 TeV taken from 2015 to 2018, with an integrated luminosity of up to 140 fb(-1), with some results based on pp and Pb+Pb data recorded at lower nucleon centre-of-mass energies. The results cover a wide range of topics, from strong production of particles at low energies and the spectroscopy of hadrons to perturbative QCD with hadronic jets and electroweak and strong production of single and multiple vector bosons. They provide precise measurements of fundamental constants and stringent tests of the Standard Model with unprecedented precision and in energy ranges never explored before. They are also used to explore the proton structure and to perform model-independent searches for new physics. (c) 2024 CERN for the benefit of the ATLAS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).CERN; NDGF (Denmark, Norway, Sweden); KIT/GridKA (Germany); INFN-CNAF (Italy); NL-T1 (Netherlands), PIC (Spain); BNL (USA) [370]; ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW; FWF, Austria; ANAS; CNPq; FAPESP, Brazil; NSERC; CFI, Canada; NSFC, China; MEYS CR, Czech Republic; DNRF; DNSRC, Denmark; IN2P3-CNRS; CEA-DRF/IRFU, France; BMBF; MPG, Germany; RGC and Hong Kong SAR, China; ISF; Benoziyo Center, Israel; INFN, Italy; MEXT; JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MNiSW, Poland; FCT, Portugal; MNE/IFA, Romania; MESTD, Serbia; MSSR, Slovakia; SRC; Wallenberg Foundation, Sweden; SNSF and Cantons of Bern and Geneva, Switzerland; NSTC, Taipei; STFC/UKRI, United Kingdom; DOE; NSF, United States of America; BCKDF; CANARIE; CRC; DRAC, Canada [PRIMUS 21/SCI/017]; FORTE, Czech Republic; ERC; ERDF; Marie Sklodowska-Curie Actions, European Union; Investissements d'Avenir Labex, Investissements d'Avenir Idex; ANR, France; DFG; AvH Foundation, Germany - EU-ESF; Greek NSRF, Greece; BSF-NSF; NCN; La Caixa Banking Foundation; CERCA Programme Generalitat de Catalunya; PROMETEO [CIDEGENT/2019/023, CIDEGENT/2019/027]; Generalitat Valenciana, Spain; Goran Gustafssons Stiftelse, Sweden; Royal Society [NIF-R1-231091]; Leverhulme Trust, United Kingdom; CERN: European Organization for Nuclear Research (CERN PJAS); Chile: Agencia Nacional de Investigacion y Desarrollo (FONDECYT) [1190886]; FONDECYT [1230987]; China: Chinese Ministry of Science and Technology [MOST-2023YFA1605700, MOST-2023YFA1609300]; National Natural Science Foundation of China [NSFC - 12175119, NSFC 12275265, NSFC-12075060]; Czech Republic: Czech Science Foundation; Ministry of Education Youth and Sports [FORTE CZ.02.01.01/00/22_008/0004632]; PRIMUS Research Programme [PRIMUS/21/SCI/017]; EU [ERC -101002463]; European Union: European Research Council [ERC -948254, ERC 101089007, MUCCA -CHIST-ERA-19-XAI-00]; European Union [FAIR-NextGenerationEU PE00000013]; France: Agence Nationale de la Recherche [ANR-20-CE31-0013, ANR-21-CE31-0013, ANR-21-CE31-0022, ANR-22-EDIR-0002]; Investissements d'Avenir Labex; Germany: Baden-Wurttemberg Stiftung; Deutsche Forschungsgemeinschaft [DFG - 469666862]; Ministero dell'Universita e della Ricerca [20223N7F8K -PNRR M4.C2.1.1]; Japan Society for the Promotion of Science (JSPS KAKENHI) [JP21H05085, JP22H01227, JP22H04944, RCN-314472, 9722]; Polish National Agency for Academic Exchange [PPN/PPO/2020/1/00002/U/00001]; Polish National Science Centre (NCN) [2021/42/E/ST2/00350]; NCN OPUS [UMO-2020/37/B/ST2/01043, UMO-2021/40/C/ST2/00187, UMO-2022/47/O/ST2/00148, UMO-2023/49/B/ST2/04085]; Slovenian Research Agency [J1-3010]; Generalitat Valenciana; FEDER [IDIFEDER/2018/048]; Ministry of Science and Innovation [NextGenEU PCI2022-135018-2]; MICIN FEDER [PID2021-125273NB, RYC2019-028510-I, RYC2020-030254-I, RYC2021-031273-I, RYC2022-038164-I]; Carl Trygger Foundation; Swedish Research Council (Swedish Research Council) [2023-04654, VR 2018-00482, VR 2022-03845, VR 2022-04683, VR 202303403, 2021-03651]; Knut and Alice Wallenberg Foundation [KAW 2018.0157, KAW 2018.0458, KAW 2019.0447, SNSF - PCEFP2_194658]; United Kingdom: Leverhulme Trust (Leverhulme Trust) [RPG-2020-004]; United States of America [ECA DE-AC02-76SF00515]; Neubauer Family FoundationWe thank CERN for the very successful operation of the LHC and its injectors, as well as the support staff at CERN and at our institutions worldwide without whom ATLAS could not be operated efficiently. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF/SFU (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), RAL (UK) and BNL (USA), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in Ref. [370]. We gratefully acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; Minciencias, Colombia; MEYS CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MNiSW, Poland; FCT, Portugal; MNE/IFA, Romania; MESTD, Serbia; MSSR, Slovakia; ARIS and MVZI, Slovenia; DSI/NRF, South Africa; MICIU/AEI, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; NSTC, Taipei; TENMAK, Turkiye; STFC/UKRI, United Kingdom; DOE and NSF, United States of America. Individual groups and members have received support from BCKDF, CANARIE, CRC and DRAC, Canada; PRIMUS 21/SCI/017, CERN-CZ and FORTE, Czech Republic; COST, ERC, ERDF, Horizon 2020, ICSC-NextGenerationEU and Marie Sklodowska-Curie Actions, European Union; Investissements d'Avenir Labex, Investissements d'Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and MINERVA, Israel; Norwegian Financial Mechanism 2014-2021, Norway; NCN and NAWA, Poland; La Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Goran Gustafssons Stiftelse, Sweden; The Royal Society and Leverhulme Trust, United Kingdom. In addition, individual members wish to acknowledge support from CERN: European Organization for Nuclear Research (CERN PJAS); Chile: Agencia Nacional de Investigacion y Desarrollo (FONDECYT 1190886, FONDECYT 1210400, FONDECYT 1230812, FONDECYT 1230987); grant sponsor China: Chinese Ministry of Science and Technology (MOST-2023YFA1605700, MOST-2023YFA1609300), National Natural Science Foundation of China (NSFC - 12175119, NSFC 12275265, NSFC-12075060); Czech Republic: Czech Science Foundation (GACR -24-11373S), Ministry of Education Youth and Sports (FORTE CZ.02.01.01/00/22_008/0004632), PRIMUS Research Programme (PRIMUS/21/SCI/017); EU: H2020 European Research Council (ERC -101002463); European Union: European Research Council (ERC -948254, ERC 101089007), Horizon 2020 Framework Programme (MUCCA -CHIST-ERA-19-XAI-00), European Union, Future Artificial Intelligence Research (FAIR-NextGenerationEU PE00000013), Italian Center for High Performance Computing, Big Data and Quantum Computing (ICSC, NextGenerationEU); France: Agence Nationale de la Recherche (ANR-20-CE31-0013, ANR-21-CE31-0013, ANR-21-CE31-0022, ANR-22-EDIR-0002), Investissements d'Avenir Labex (ANR-11-LABX-0012); Germany: Baden-Wurttemberg Stiftung (BW Stiftung-Postdoc Eliteprogramme), Deutsche Forschungsgemeinschaft (DFG - 469666862, DFG - CR 312/52); Italy: Istituto Nazionale di Fisica Nucleare (ICSC, NextGenerationEU), Ministero dell'Universita e della Ricerca (PRIN - 20223N7F8K -PNRR M4.C2.1.1); Japan: Japan Society for the Promotion of Science (JSPS KAKENHI JP21H05085, JSPS KAKENHI JP22H01227, JSPS KAKENHI JP22H04944, JSPS KAKENHI JP22KK0227); Netherlands: Netherlands Organisation for Scientific Research (NWO Veni 2020 - VI.Veni.202.179); Norway: Research Council of Norway (RCN-314472); Poland: Ministry of Science and Higher Education (IDUB AGH, POB8, D4 no 9722), Polish National Agency for Academic Exchange (PPN/PPO/2020/1/00002/U/00001), Polish National Science Centre (NCN 2021/42/E/ST2/00350, NCN OPUS nr2022/47/B/ST2/03059, NCN UMO-2019/34/E/ST2/00393, NCN ; H2020 MSCA 945339, UMO-2020/37/B/ST2/01043, UMO-2021/40/C/ST2/00187, UMO-2022/47/O/ST2/00148, UMO-2023/49/B/ST2/04085); Slovenia: Slovenian Research Agency (ARIS grant J1-3010); Spain: Generalitat Valenciana (Artemisa, FEDER, IDIFEDER/2018/048), Ministry of Science and Innovation (MCIN ; NextGenEU PCI2022-135018-2, MICIN ; FEDER PID2021-125273NB, RYC2019-028510-I, RYC2020-030254-I, RYC2021-031273-I, RYC2022-038164-I), PROMETEO and GenT Programmes Generalitat Valenciana (CIDEGENT/2019/023, CIDEGENT/2019/027); Sweden: Carl Trygger Foundation (Carl Trygger Foundation CTS 22:2312), Swedish Research Council (Swedish Research Council 2023-04654, VR 2018-00482, VR 2022-03845, VR 2022-04683, VR 202303403, VR grant 2021-03651), Knut and Alice Wallenberg Foundation (KAW 2018.0157, KAW 2018.0458, KAW 2019.0447, KAW 2022.0358); Switzerland: Swiss National Science Foundation (SNSF - PCEFP2_194658); United Kingdom: Leverhulme Trust (Leverhulme Trust RPG-2020-004), Royal Society (NIF-R1-231091); United States of America: U.S. Department of Energy (ECA DE-AC02-76SF00515), Neubauer Family Foundation
Enhancing Efficiency of an Old Hydropower Plant Turbine Through a Mutual Runner Design and Component Optimization
No full textThis paper presents a systematic approach to the rehabilitation process of Sarıyar HEPP, a hydroelectric power plant that has been operational for more than 50 years. Units 1 and 2 (U1-U2) were originally designed with a head of 93 m and a turbine power of 48.5 MW, while Units 3 and 4 (U3-U4) were designed with a lower head of 76.5 m but the same turbine power of 48.5 MW. A methodology combining reverse engineering and CFD analysis is developed to identify and evaluate the critical parameters that have an impact on the existing turbine performance. A hybrid design is proposed to replace the existing two different types of turbines, which reduces manufacturing costs and design time. The performance of the new hybrid design is evaluated in detail with CFD analysis. For both existing and hybrid design, steady and unsteady analyses are performed. For all of the situations hill charts are obtained and the comparison of the old and new hybrid design is discussed in detail. The results show that the new design has improved the efficiency of the turbine and the power plant, resulting in a 14.2% efficiency increase in U1-U2 and a 21% system efficiency improvement in U3-U4. This study provides a guide to designers and practitioners for the rehabilitation of hydroelectric power plants. © IMechE 2025.TOBB University of Economics and Technology Hydro Energy Research Center; ETU Hydro Laboratory; Turkish Ministry of Development; Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTA
Clu Polymorphisms and Plasma Clusterin Levels in Patients With Multiple Sclerosis: Association With Disability Scores, Progression Rate and Fingolimod Therapy
No full textObjectives: Multiple sclerosis (MS) is a chronic, demyelinating disorder of the central nervous system that is widely accepted to result from a complex interplay of genetic and environmental factors. The involvement of clusterin in neurodegenerative and autoimmune diseases has been highlighted, but its role in MS remains unclear. This study aimed to investigate the association of four single nucleotide polymorphisms (SNPs) in the clusterin gene (CLU) with MS susceptibility. Methods: The study group consisted of 310 patients with RRMS (pwRRMS) and 310 controls. 25 treatment-na ; iuml;ve pwRRMS, 25 pwRRMS on fingolimod treatment and 25 controls composed a subgroup for further analysis. The genotypes of 4 CLU SNPs were determined using either restriction endonuclease digestion following PCR (rs11136000 ; rs3087554) or the real-time PCR method using TaqMan genotyping assays (rs2279590 ; rs1532278). Plasma clusterin concentration was determined by ELISA in the subgroup (n = 75). Results: Our results revealed that CLU rs3087554 C allele (p = .008) and TC + CC genotype were significantly associated with RRMS (p = .002). Furthermore, haplotype analysis has also shown that T-C-T-T haplotype was associated with RRMS (p .001). Moreover, plasma clusterin concentrations were significantly higher in pwRRMS on fingolimod therapy compared to treatment-na ; iuml;ve pwRRMS and the control group. In addition, plasma clusterin concentration was increased in patients with rs11136000 ; rs1532278 CC genotypes in the subgroup. Discussion: These findings suggest that CLU SNPs and plasma clusterin concentrations could serve as significant biomarkers at different stages of MS
Sağlık Ekonomisi Üzerine Makaleler
No full textThis thesis consists of three empirical chapters investigating the impact of education policies, stressful life events (SLEs), and pronatalist rhetoric on individuals' health behaviors and fertility preferences. The chapters rely on three distinct data sources: the Turkish Health Survey (THS), the German TwinLife, and the Turkish Demographic and Health Surveys (TDHS). Employing a range of empirical strategies, including fuzzy regression discontinuity design (RDD), conditional (fixed-effects) logistic regression, and Difference-in-Differences (DiD), the thesis provides novel evidence in research areas that have not been previously addressed in the literature. The first chapter investigates the causal impact of Türkiye's 2012 compulsory schooling reform, which extended mandatory education from 8 to 12 years, on smoking behavior. Using nationally representative data from the THS for 2019 and 2022, the chapter exploits the exogenous variation in educational attainment induced by the reform and employs a fuzzy RDD. The second chapter explores the association between SLEs and risky health behaviors, including smoking, excessive alcohol consumption, and drug use, using a twin-based research design. Although some studies emphasize the role of genetic and familial factors in shaping such behaviors, many cross-sectional approaches fail to control for these unobserved confounders. This chapter addresses this limitation by using data from the German TwinLife, which includes monozygotic and dizygotic same-sex twin pairs. The third chapter investigates the causal effect of the Prime Minister's pronatalist rhetoric on fertility preferences in Türkiye. Using data from the TDHS of 2008 and 2013, and cohort-based variation in exposure to the rhetoric as an identification strategy, the chapter employs a DiD approach.Bu tez, eğitim politikalarının, stresli yaşam olaylarının ve doğum yanlısı söylemlerin bireylerin sağlık davranışları ve doğurganlık tercihleri üzerindeki etkisini inceleyen üç ampirik bölümden oluşmaktadır. Bölümler, Türkiye Sağlık Araştırması (TSA), German Twin Family Panel (TwinLife) ve Türkiye Nüfus ve Sağlık Araştırmaları (TNSA) olmak üzere üç farklı veri setine dayanmaktadır. Bulanık regresyon süreksizlik tasarımı, koşullu sabit etkiler lojistik regresyon modeli ve Farkların Farkı gibi çeşitli ekonometrik yöntemlerin kullanıldığı tez, literatürde daha önce ele alınmamış alanlara özgün katkılar sunmaktadır. Birinci bölüm, Türkiye'de zorunlu eğitimin süresini 8 yıldan 12 yıla çıkaran 2012 eğitim reformunun sigara kullanımı üzerindeki nedensel etkisini incelemektedir. 2019 ve 2022 yıllarına ait TSA verileri kullanılarak, reformdan kaynaklanan eğitim süresi farklılıkları incelenmiş ve bulanık regresyon süreksizlik yöntemi uygulanmıştır. İkinci bölüm, stresli yaşam olayları ile sigara kullanımı, aşırı alkol tüketimi ve uyuşturucu madde kullanımı gibi riskli sağlık davranışları arasındaki ilişkiyi, ikiz temelli bir tasarım kullanarak incelemektedir. Bu bölüm, aynı cinsiyetteki tek ve çift yumurta ikizlerini içeren Alman TwinLife verisini kullanarak kesitsel yaklaşıma dayalı çalışmaların göz ardı ettiği gözlemlenemeyen genetik ve ailesel faktörleri dikkate almaktadır. Üçüncü bölüm, dönemin başbakanının doğum yanlısı söyleminin Türkiye'deki doğurganlık tercihleri üzerindeki nedensel etkisini incelemektedir. Çalışmada, 2008 ve 2013 yıllarına ait TNSA verileri kullanılarak; söyleme maruz kalma düzeyinde, doğum yılına bağlı farklılıklar dikkate alınarak Farkların Farkı yöntemi uygulanmaktadır
Polythiophene Block Copolymer-Perylene Diimide-Based Electron Donor-Acceptor Double-Cable Polymer and Its Potential as an All-Organic Photocatalyst for Artificial Photosynthesis of H2O2
No full textEnhancing the light energy harvesting and conversion capabilities of all-organic photoactive materials is of significant scientific interest. Herein, we report the synthesis of a photoactive double-cable polymer (DCP) consisting of a polythiophene (PTh) block copolymer electron donor (D) conjugated to a perylene diimide (PDI) electron acceptor (A). GRIM polymerization and postsynthetic modifications are employed to synthesize the block copolymer [P3HT-b-poly(3-HT-co-PTh/PDI)] consisting of a poly-3-hexylthiophene (P3HT) block and a block comprising of randomly distributed repeat units bearing hexyl and PDI groups. Besides H-1 NMR, ATR-FTIR, UV/visible, and fluorescence spectroscopic characterizations, AFM and XRD analyses are performed to reveal self-assembly and crystallinity behaviors. Compared to P3HT, PDI, and their physical hybrid (P3HT-PDI-PH), the P3HT-b-poly(3-HT-co-PTh/PDI) shows superior D-A electronic communication, higher (photo)electrochemical current, faster electrochemical kinetics, and lower charge transfer resistance. The photocatalytic performance of all photocatalysts in the artificial photosynthesis of H2O2 is demonstrated over 10 photocatalytic cycles. Comparing the results from the highest H2O2 producing cycles, the photocatalytic performance of P3HT-b-poly(3HT-co-Th/PDI) is similar to 2.1, similar to 3.2, and similar to 1.9 times superior compared to that of P3HT, PDI, and P3HT-PDI-PH, respectively. In summary, this work contributes to the development of organic semiconducting polymer-based photoactive materials for application in light energy harvesting and conversion technologies.Lahore University of Management Sciences [20-15989]; Higher Education Commission (HEC) of Pakistan; Faculty Initiative Fund (FIF); LUMS [RGY0074/2016]; HFSP [20-1740/RD/10/3368, 1799/RD/10-5302, 5922, TDF-033]; HEC for NRPUThis work was financially supported by the Higher Education Commission (HEC) of Pakistan (NRPU Project No.20-15989) and the Faculty Initiative Fund (FIF), LUMS. B.Y. acknowledges support from HFSP (RGY0074/2016), HEC for NRPU (Project Nos. 20-1740/R;D/10/3368, 20-1799/R;D/10-5302, and 5922), and TDF-033 grants, and LUMS for start-up fund. Support from Prof. Raja Shahid (GCU) for the steady-state fluorescence spectroscopy is highly appreciated
Çok Modlu Veri ile Hisse Senedi Fiyati Tahmini
No full textIsik UniversityIn today's financial markets, the influence of dynamic factors is becoming increasingly evident, and markets are affected by real-time data from various sources. In this study, a multimodal machine learning approach is adopted by integrating traditional technical analysis metrics, tweets, and news articles with historical price data. Market sentiment and investor psychology are measured through sentiment analysis of textual data using both the FinBERT and ChatGPT-4o models, and the obtained outputs are combined with financial metrics to construct an LSTM-based stock price prediction model. To enhance the model's stability, LSTM models derived from different training sessions are merged using an ensemble learning method, and the two approaches are compared. The results demonstrate that the ensemble model outperforms the standard LSTM model, and integrating financial indicators with tweet and news data, as opposed to relying solely on price data, leads to increased overall profit. © 2025 Elsevier B.V., All rights reserved
Uluslararası Hukukta Rusya-Ukrayna Sorunu ve Rusya'ya Uygulanan Yaptırımlar
No full textThis thesis will analyze Russia's actions in Ukraine and evaluate to what extent the coercive measures under international law are efficient, proportionate, specific and lawful based on the sanctions imposed against Russia. In the first chapter, the recent historical process of Russia-Ukraine relations will be summarized to understand the root causes of the ongoing crisis. Subsequently, the compliance with international law of the unilateral declarations of independence in eastern Ukraine and Russia's recognition and annexation of Crimea, the Donetsk People's Republic and the Luhansk People's Republic, which declared their independence, will be examined. In the second chapter, the 'Special Military Operation' launched by Russia on February 24, 2022, will be analyzed within the scope of the prohibition of use of force; in this context, the sanctions taken against Russia by international organizations and states will be elaborated. The ultimate objective is to identify the deficiencies in the enforcement of international law and responsibility of states through sanctions taken against Russia.Bu tezde, Rusya'nın Ukrayna'daki fiilleri incelenerek, Rusya'ya uygulanan yaptırımlar temelinde, uluslararası hukuktaki zorlayıcı önlemlerin ne derecede etkili, ölçülü, belirli ve hukuka uygun olduğu tartışılacaktır. Birinci bölümde, RusyaUkrayna ilişkilerinin yakın tarihsel süreci, halihazırda devam eden krizin temel nedenlerine hâkim olmak amacıyla, ana hatlarıyla ele alınacaktır. Devamında, Ukrayna'nın doğusundaki tek taraflı bağımsızlık ilanları ile Rusya'nın, bağımsızlığını ilan eden Kırım, Donetsk Halk Cumhuriyeti ve Luhansk Halk Cumhuriyeti'ni tanıması ve ilhak etmesinin uluslararası hukuka uygunluğu incelenecektir. İkinci bölümde, Rusya'nın Ukrayna'ya karşı 24 Şubat 2022'de başlattığı 'Özel Askerî Harekât', uluslararası hukuktaki kuvvet kullanma yasağı bakımından değerlendirilerek; bu kapsamda, uluslararası örgütler ve devletler tarafından Rusya'ya uygulanan yaptırımlar incelenecektir. Rusya'ya uygulanan yaptırımlar üzerinden devletlerin uluslararası sorumluluğunun işletilmesindeki eksikliklerinin tespit edilmesi amaçlanmaktadır
Eklemeli İmalat ile Üretilen Kafes Yapılı Bir Uydu Panelinin Isıl İletkenliğinin Vakum Ortamında İncelenmesi
No full textSon yıllarda eklemeli imalat (Eİ) teknolojisi, uzay endüstrisinde yapısal alt sistemlerin tasarımında giderek daha fazla tercih edilmeye başlanmıştır. Geleneksel üretim yöntemleri, özellikle bal peteği yapılı sandviç panellerin üretimindeki yüksek işçilik maliyetleri, karmaşık kalite kontrol süreçleri ve hassas tolerans gereksinimleri gibi çeşitli zorluklar barındırmaktadır. Bu sınırlamaları aşmak amacıyla kullanılan Eİ, malzemeleri ardışık katmanlar halinde birleştirerek karmaşık geometrilere sahip hafif ve yüksek mukavemetli yapılar üretilmesine olanak tanımaktadır. Uzay yapısallarında Eİ'nin sağladığı tasarım esnekliği sayesinde, optimize edilmiş kafes yapılar geliştirilmekte ve bu sayede hem mekanik dayanım hem de ısıl performans açısından önemli iyileştirmeler sağlanmaktadır. Literatürde, Eİ ile üretilen ısı eşanjörleri, soğutucu yapılar ve ısı boruları gibi ısıl kontrol bileşenlerinin başarılı uygulamaları mevcuttur. Bu durum, Eİ'nin uzay sektöründe giderek yaygınlaşmasını desteklemekte ve uydu yapısal alt sistemlerinde önemli bir yenilik olarak değerlendirilmesini sağlamaktadır. Bu tez çalışması, uydu yapısal alt sisteminde kullanılmak üzere tasarlanan kafes yapılı sandviç panellerin ısıl iletkenliklerini analitik, sayısal ve deneysel yöntemlerle incelemeyi amaçlamaktadır. Çalışmada, farklı çubuk çaplarına sahip kafes yapılı panellerin ısıl iletkenlik performansları değerlendirilmiştir. Literatür taramasıyla, kafes yapılar için gerçekleştirilen çalışmalar incelenerek elde edilen bulgular doğrultusunda analitik, sayısal ve deneysel yöntemler kullanılarak analizler gerçekleştirilmiştir. Analitik ve sayısal yöntemlerden elde edilen sonuçlar karşılaştırıldığında, çubuk çapına göre %0,8 ile %6,3 arasında değişen farklılıklar gözlemlenmiştir. Bu farklılıklar, literatürde kabul edilen hata payları içinde kalmaktadır. Ayrıca, analizler kafes yapının çubuk çapı ile ısıl iletkenlik arasında doğru orantılı bir ilişki olduğunu ortaya koymuştur. Panel tasarımlarından en küçük çubuk çapına sahip olan panel bir metal Eİ yöntemi olan Seçici Lazer Ergitme (SLE) yöntemiyle üretilmiştir. Bu panel, uydu yapısal alt sisteminde kullanılmak üzere tasarlandığı için, uzay ortamını simüle etmek amacıyla vakum ortamında ısıl testlere tabi tutulmuştur. Deneysel sonuçlar, analitikhesaplamalardan maksimum %9'luk bir sapma göstermiştir. Bu sapma, test ortamındaki belirsizlikler ve üretim sürecindeki geometrik farklılıklar gibi etmenlerden kaynaklanmış olabileceği değerlendirilmiştir. Ayrıca, deneyde gözlemlenen panelin ısıl iletim davranışının bilgisayar ortamında simüle edilmesi amacıyla, deney düzeneğinin sonlu elemanlar modeli oluşturulmuştur. Bu model için gerçekleştirilen sayısal analizler sonucunda elde edilen sıcaklıklar ile deneysel ölçümler arasındaki farklar ± 1,5°C'lik ölçüm hassasiyeti içinde kalmıştır.In recent years, additive manufacturing (AM) technology has widely been preferred in the design of structural subsystems within the space industry. Traditional manufacturing methods present various challenges, particularly in the production of honeycomb sandwich panels, including high labor costs, complex quality control processes, and stringent tolerance requirements. To overcome these limitations, AM enables the fabrication of lightweight and high-strength structures with complex geometries by sequentially joining material layer by layer. The design flexibility offered by AM in space structures facilitates the development of optimized lattice structures, leading to significant improvements in both mechanical strength and thermal performance. The literature includes successful applications of AM-fabricated thermal control components, such as heat exchangers, heat sinks, and heat pipes. This trend supports the increasing adoption of AM in the space sector and highlights its potential as a significant innovation in satellite structural subsystems. This thesis aims to investigate the thermal conductivity of lattice-core sandwich panels designed for satellite structural subsystem through analytical, numerical, and experimental methods. In this study, the thermal conductivity performance of lattice-core sandwichpanels with different strut diameters has been evaluated. A literature review was conducted, and based on the findings from studies on lattice structures, analyses were carried out using analytical, numerical, and experimental approaches. When comparing the results obtained from the analytical and numerical methods, differences ranging from 0.8% to 6.3% were observed as a function of the strut diameter. These differences stay within the error margins typically accepted in the literature. Additionally, the analyses revealed a directly proportional relationship between the strut diameter of the lattice structure and its thermal conductivity. Due to the high production and testing costs, only one of the designed panels was produced using the Selective Laser Melting (SLM), one of the metal AM technologies. Since this panel was designed for satellite structural subsystem, it was tested in a vacuum environment to simulate the space conditions. Experimental results showed a maximum difference of 9% from theoretical calculations. This difference is believed to be due to factors such as uncertainties in the test environment and geometric variations during the manufacturing process. Furthermore, to simulate the thermal behavior of the panel observed in the experiment, a finite element model of the experimental setup was created. The numerical analysis performed on this model resulted in temperature differences between the numerical predictions and experimental measurements, which generally stayed within a thermal uncertainty margin of ±1.5 °C
Türkiye'de Asgari Ücret ve İstihdam Teşviklerinin Firmaların İstihdam, Yatırım ve İhracat Kararlarına Etkisi
No full textBu tez, hem düzenleyici hem de teşvik temelli ücret politikalarının, gelişmekte olan bir ekonomi bağlamında firma davranışı ve işgücü piyasası sonuçlarını nasıl şekillendirdiğini incelemektedir. Türkiye'ye ait kapsamlı idari mikro verilerden ve yarı-deneysel politika değişimlerinden faydalanarak, asgari ücret artışlarının ve istihdam teşviklerinin firma düzeyinde istihdam, sermaye birikimi, işgücü bileşimi ve ihracat davranışı üzerindeki etkileri araştırılmaktadır. İlk çalışmada, 2016 yılında gerçekleşen asgari ücret artışı yığılma ('bunching') tahmin yöntemi kullanılarak analiz edilmiştir. Bulgular, istihdam üzerindeki etkinin özellikle asgari ücrete yakın dilimlerde yoğunlaştığını; bu etkinin en çok kayıtlı çalışanlar, düşük vasıflı bireyler ve gençler üzerinde olumsuz olduğunu göstermektedir. Bu sonuçlar, yasal ücret tabanlarının etkisini değerlendirirken, ücret dağılımındaki heterojenliğin önemine işaret etmektedir. İkinci çalışmada, 2016 yılında yürürlüğe giren ve daha önce bu kapsama dahil olmayan mikro ölçekli firmalara işveren taraflı sosyal güvenlik primlerinde 6 puanlık bir indirim sunan teşvik uygulaması ele alınmaktadır. Bölgesel uygunluk farklarını kullanan bir farkların farkı yaklaşımıyla yapılan analiz, mikro firmaların anlamlı düzeyde istihdam artışıyla yanıt verdiğini, küçük ölçekli firmaların ise maddi duran varlık şeklindeki sermaye yatırımlarını ve sermaye–emek oranlarını artırdığını ortaya koymaktadır. Bununla birlikte, politika işgücü niteliğinde bir artışa yol açmamış, bu da yapısal dönüşüm sağlama açısından teşvik sınırlı etkisini gözler önüne sermiştir. Üçüncü çalışmada aynı teşvik uygulamasının ihracat davranışı üzerindeki etkisi incelenmektedir. Yapılan analiz, politikanın yoğun marjda—özellikle mikro firmalar için—ihracat performansını belirgin şekilde artırdığını göstermektedir. Buna karşın, politika yaygın marj üzerinde anlamlı bir etki yaratmamış; yani ihracat yapmayan firmaların uluslararası pazarlara girmesini teşvik etmemiştir. Genel olarak tez, ücret politikalarının finansal kısıt altındaki firmalarda istihdamı ve yatırımı etkili biçimde teşvik edebileceğini, ancak yapısal dönüşüm ve ihracat artışı gibi uzun vadeli hedefler için tamamlayıcı müdahaleler olmadan bu etkilerin sınırlı kalabileceğini ortaya koymaktadır.This thesis investigates how wage policies—both regulatory and incentive-based—shape firm behavior and labor market outcomes in a developing economy context. Using rich administrative microdata from Turkey and leveraging quasi-experimental variation, the study explores the effects of minimum wage hikes and employment subsidies on firm-level employment, capital accumulation, workforce composition, and export behavior. The first chapter analyzes the 2016 minimum wage hike using a bunching estimation framework. The results show that the employment effects are concentrated near the wage threshold, with negative impacts particularly evident among formal, low-skilled, and young workers. These findings underscore the importance of heterogeneity in the wage distribution when evaluating the impact of statutory wage floors. The second chapter explores the impact of a 2016 subsidy reform that extended a 6-percentage-point reduction in employer-side social security contributions to previously ineligible micro firms. Exploiting regional eligibility variation in a difference-in-differences design, the study finds that micro firms responded with significant employment gains, while small firms increased capital investment and capital–labor intensity in the form of tangible assets. However, the policy had no measurable effect on skill upgrading, highlighting its limits in fostering structural labor market transformation. The third chapter evaluates whether the same wage subsidy influenced export behavior. The analysis reveals that the policy significantly improved export performance along the intensive margin, particularly for micro firms. In contrast, the policy had no significant impact on the extensive margin, suggesting it did not induce non-exporting firms to enter foreign markets. Overall, the thesis shows that wage policies can effectively stimulate employment and investment in financially constrained firms, but their impact on structural upgrading and export expansion remains limited without complementary interventions. These findings inform labor market policy design in middle-income economies where informality, inequality, and productivity differentials continue to pose major challenges