154 research outputs found
Torque-Controlled Adaptive Speed Control on a CNC Marble Saw Machine
No full textAlthough CNC marble saw machines can automatically cut marble slabs to desired dimensions, saw speed and feed rate are selected by operator according to stone parameters, features of the saw, and its immersion depth. If the feed rate is selected lower than the optimal value, there will be time-loss and capacity deficiencies or if it is selected faster, cutting quality will decrease, spindle motor will draw more current, and saw blade will corrode faster. While cutting especially thick materials, saw may be stacked in the stone, cutting quality may be impaired, saw blade may be abraded earlier, precision quality may go down because of increase in measurement errors, and machine may be damaged with the increase in vibrations when improper feed rates are selected. Because of nonhomogeneity of the slabs and deterioration of the saw blade, operator cannot determine a persistent feed rate. This study is targeted to find saw speeds according to saw diameter and optimum feed rate by means of limiting vibrations and current drawn from saw motor and torque accordingly in order to increase working performance of CNC marble saw machines. Thanks to adaptive adjustment of feed rate, one can save on material as well as time, labour, and cost by making use of optimum energy
Prediction of Position and Course of a Vessel Using Artificial Neural Networks by Utilizing GPS/Radar Data
No full textMachine selection for inventory tracking with a continuous intuitionistic fuzzy approach
No full textToday, businesses are adopting digital transformation strategies to make their production processes more agile, efficient, and sustainable. At the same time, lean manufacturing principles aim to create value by reducing waste in production processes. In this context, it is important that the machine to be selected for inventory tracking can meet both the technological features suitable for digital transformation goals and the operational efficiency criteria required by lean manufacturing. In this study, multi-criteria decision-making methods were used to select the most suitable machine for inventory tracking based on digital transformation and lean manufacturing perspectives. This study applies a framework that integrates the Continuous Intuitionistic Fuzzy Analytic Hierarchy Process (CINFU AHP) and the Continuous Intuitionistic Fuzzy Combinative Distance-Based Assessment (CINFU CODAS) methods to select the most suitable machine for inventory tracking. The framework contributes to lean manufacturing by providing actionable insights and robust sensitivity analyses, ensuring decision-making reliability under fluctuating conditions. The CINFU AHP method determines the relative importance of each criterion by incorporating expert opinions. Six criteria, Speed (C1), Setup Time (C2), Ease to Operate and Move (C3), Ability to Handle Multiple Operations (C4), Maintenance and Energy Cost (C5), and Lifetime (C6), were considered in the study. The most important criteria were C1 and C4, with scores of 0.25 and 0.23, respectively. Following the criteria weighting, the CINFU CODAS method ranks the alternative machines based on their performance across the weighted criteria. Four alternative machines (High-Speed Automated Scanner (A1), Multi-Functional Robotic Arm (A2), Mobile Inventory Tracker (A3), and Cost-Efficient Fixed Inventory Counter (A4)) are evaluated based on the criteria selected. The results indicate that Alternative A1 ranked first because of its superior speed and operational efficiency, while Alternative A3 ranked last due to its high initial cost despite being cost-effective. Finally, a sensitivity analysis further examines the impact of varying criteria weights on the alternative rankings. Quantitative findings demonstrate how the applied CINFU AHP&CODAS methodology influenced the rankings of alternatives and their sensitivity to criteria weights. The results revealed that C1 and C4 were the most essential criteria, and Machine A2 outperformed others under varying weights. Sensitivity results indicate that the changes in criterion weights may affect the alternative ranking
Risk Analysis of Five-Axis CNC Water Jet Machining Using Fuzzy Risk Priority Numbers
No full textThe reliability and safety of five-axis CNC abrasive water jet machining are critical for many industries. This study employs Failure Mode and Effects Analysis (FMEA) to identify and mitigate potential failures in this machining system. Traditional FMEA, which relies on crisp numerical values, often struggles with handling uncertainty in risk assessment. To address this limitation, this paper introduces an Interval-Valued Spherical Fuzzy FMEA (IVSF-FMEA) approach, which enhances risk evaluation by incorporating membership, non-membership, and hesitancy degrees. The IVSF-FMEA method leverages the inherent rotational symmetry of interval-valued spherical fuzzy sets and the permutation symmetry among severity, occurrence, and detectability criteria, resulting in a transformation-invariant and unbiased risk assessment framework. Applying IVSF-FMEA to seven periodic failure (PF) modes in five-axis CNC water jet machining achieves a more precise prioritization of risks, leading to improved decision-making and resource allocation. The findings highlight improper fixturing of the workpiece (PF6) as the most critical failure mode, with the highest RPN value of −0.54, followed by mechanical vibrations (PF2) and tool wear and breakage (PF1). This indicates that ensuring proper fixturing stability is essential for maintaining machining accuracy and preventing defects. Comparative analysis with traditional FMEA demonstrates the superiority of the proposed fuzzy-based approach in handling subjective assessments and reducing ambiguity. The findings highlight improper fixturing, mechanical vibrations, and tool wear as the most critical failure modes, necessitating targeted risk mitigation strategies. This research contributes to advancing risk assessment methodologies in complex manufacturing environments
LaFontaine Seçme Masallar [Cover: LaFontaine'den Massallar]
No full textAbout this Turkish book I will not be able to write much. Its dust jacket cover features a composite picture of animals involved in La Fontaine's fables. Inside, there is a life of La Fontaine, followed by fables without illustration on 7-124. At the end, before advertisements for the publisher's series of thirty classics and of one hundred fairytale books, there is an alphabetical index. My purchase of this book from Ugur has led us to several transactions, as he keeps finding me more Turkish fable books.This is a hardbound book (hard cover)This book has a dust jacket (book cover)Language note: TurkishOriginal language: freErenler Matbaas
Learning Hierarchical Task Networks from Traces and Semantically Annotated Tasks
No full textiii iv Acknowledgements I wish to thank the following persons, without whom this work would not have been possible: • My wife Rachel, who lovingly and expertly brandished carrots and sticks to ensure progress over the last year. • My parents Jeffrey and Cynthia who supported me through both my childhood and eleven years of post-secondary education. • My advisor, Héctor Muñoz-Avila, who has been a source of funding, knowl-edge, inspiration, and friendship for the past five years. • My frequent co-author Ugur Kuter, whose ideas strongly influenced Chapters 4 and 5 in particular. • My other committee members, Brian Davison, Jeff Heflin, and Henry Baird, each of whom have been available and helpful throughout my time at Lehigh
A Comparison of the Inhibitory Effects of Anti-Cancer Drugs on Thioredoxin Reductase and Glutathione S-Transferase in Rat Liver
No full textWOS: 000458732100013PubMed: 30198440Background: While Thioredoxin Reductase (TrxR) plays an important role in regulation of the intracellular redox balance and various signalling pathways, Glutathione S-Transferase (GSTs) enzymes belong to the detoxification family that catalyse the conjugation of glutathione with various endogenous and xenobiotic electrophiles. Since TrxR and GSTs are overexpressed in many cancer cells, they have been identified as potential targets to develop chemotherapeutic strategies. Method: The mitochondrial TrxR (TrxR2) enzyme and the cytosolic CYST enzyme was purified from rat liver via affinity chromatography. After the purification, the in vitro inhibition effects of some anticancer drugs (cisplatin, calcium folinate, carboplatin, epirubicin hydrochloride, doxorubicin hydrochloride, paclitaxel, etoposide, fluorouracil, and methotrexate) were investigated on both enzymes. Since only methotrexate inhibits both enzymes among all the anticancer drugs, a molecular docking study was performed to determine the binding site and the binding affinity of methotrexate to the enzymes. Results: Firstly, TrxR2 and GST were found to have a specific activity of 0.436, 1765 EU/mg proteins with a yield of 39.20%, 31.28% and 207.6, 3516.6 of purification fold, respectively. While TrxR2 was strongly inhibited by all of the anticancer drugs, GST was not inhibited by any of the anticancer drugs except methotrexate. Conclusion: Both enzymes were inhibited by only methotrexate in rat liver, and methotrexate was well placed in the active sites of both proteins. Therefore, it may be argued that methotrexate may be a more effective anticancer drug than all other drugs used in this study against the multi drug resistance that will occur during chemotherapy.Ataturk University Scientific Research Projects Coordination Commission (ATAUNIBAP)Ataturk University [PRJ2015/97, PRJ2015/357]This work was financially supported by Ataturk University Scientific Research Projects Coordination Commission (ATAUNIBAP) with project number PRJ2015/97 and PRJ2015/357. The author(s) have no potential conflict of interest with respect to the research, authorship, and/or publication of this article. Conceived and designed the experiments: Harun Budak (group leader) and Ilknur Ozgencli. Performed the experiments: Harun Budak, Ilknur Ozgencli, Deryanur Kilic, Ugur Guller, Mehmet Ciftci, and Omer I. Kufrevioglu. Analysed the data: Harun Budak, Ilknur Ozgencli, Deryanur Kilic, and Ugur Guller. Contributed reagents/materials/analysis tools: Harun Budak. Wrote the paper: Harun Budak, Ilknur Ozgencli, Deryanur Kilic, and Ugur Guller. All authors read and approved the final manuscript
The Question of the Transfer of Evliya Celebi's Seyahatnarne (Book of Travels.) to the Topkapi Palace Library
No full textAlthough so many important studies have been carried out about the Seyahatname (Book of Travels) of Evliya Celebi until now, they haven't been benefited from Turkish archives during these studies sufficiently. Correspondingly, it is clear that lots of problems can not be clarified without using these sources. In this study, on the basis of estates, new findings have been established about how and when author's edition of Seyahatname passed to Topkapi Palace Library. Besides with the help of these estates it has been revealed that Morali Besir Aga who was one of the chief harem eunuchs possessed the author's edition and they were transported to the Palace by confiscatio
Molecular contamination phenomena in EUVL and mitigation methods with hydrogen
No full textIn accordance with Gordon Moore’s law, the number of transistors that can be placed on an integrated chip of a certain size is increasing exponentially. This can only be realized with an increase in the spatial resolution of the lithography systems, allowing smaller feature sizes to be printed. Today, Extreme ultraviolet lithography (EUVL), employing a wavelength of 13.5 nm, is the prospective method that fits in this evolution. To focus the generated EUV light, specifically tailored Mo/Si multilayer mirrors are employed, which must keep their reflectivity for 30,000 hours of operation. Therefore contamination on the mirror surfaces (e.g., oxidation, carbon contamination, metal contamination) needs to be prevented. To this end, a thin capping layer (e.g., Ru, Rh, TiO2, ZrO2) can be applied on top of the mirror surfaces. Nevertheless even capped mirrors are prone to contamination upon prolonged use in EUVL. With all the active contamination mechanisms evident in the EUV chamber, the development of effective mitigation methods is required. In this study, the contamination phenomena on the EUVL mirrors and some prospective mitigation methods were studied. It was observed that an oxide film, growing on top of a Ru capped surface, can be removed effectively by exposing it to atomic or molecular hydrogen. It was found that the atomic hydrogen cleaning process proceeded more efficiently, compared with the molecular hydrogen cleaning process. Another type of contamination was observed to arise from metal hydride generation and decomposition phenomena in EUVL. Dedicated pair of quartz crystal microbalances were used to determine the kinetics of generation and decomposition of Sn hydrides. It was shown that atomic hydrogen species are prone to form volatile metal hydrides from Sn deposits, which can subsequently decompose on vital optical surfaces. Nevertheless, capping layers made of a stable metal oxide display significant resistance to this metallic contamination compared to metallic capping layers. To determine quantitatively the flux of atomic hydrogen incident on the exposed surfaces, a highly accurate and sensitive sensor was developed.Materials Science and EngineeringMechanical, Maritime and Materials Engineerin
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