WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394

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  • Article
    Dayım: Bir İnsanoğlunun Portresi
    (TURKISH LIBRARIANS ASSOC, YENISEHIR, NECATIBEY CAD, ELGIN SOK, PO BOX 175, ANKARA, 06440, TURKEY, 2019) Donmez, Rasim Ozgur
    This is a memoir written by his nephew about our colleague Ali Can, who passed away in last July.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 10
    The Size and Concentration Effects of Al2O3 Nanoparticles on PSF Membranes With Enhanced Structural Stability and Filtration Performance
    (Desalination Publ, 2017-07) Saki, Seda; Uzal, Nigmet; Ates, Nuray
    Nanocomposite membranes have attracted attention for their high permeability, rejection efficiency, and thermal and mechanical stability. In this study, novel flat-sheet polysulfone nanocomposite membranes were prepared by a phase inversion method with polyethylenimine and Al2O3 nanoparticles to increase the flux and hydrophilicity. Al2O3 nanoparticles were added to the membrane matrix to enhance the permeability, selectivity, and mechanical resistance. Two different sizes of Al2O3 nanoparticles (20 and 80 nm) were used with different weight percentages of 0.2, 1, and 5 wt%. The effects of the size and concentration of the nanoparticles on the structural properties and filtration performance of the membranes were investigated. Scanning electron microscopy, Fourier transform infrared spectroscopy, porosity, water contact angle, thermogravimetric analysis, viscosity, and tensile strength measurements were used to characterize the prepared membranes. The membrane performance was evaluated with water flux and bovine serum albumin rejection tests. According to the results, the membrane containing 15 wt% polysulfone, 1 wt% polyethylenimine, and 5 wt% 20 nm Al2O3 showed the highest pure water flux, porosity, viscosity, and morphological stability. This membrane may have potential uses in water treatment applications.
  • Article
    Citation - WoS: 4
    Strategic Sustainable Site Management in Higher Education Institutions
    (deomed Publ, Istanbul, 2016-12-01) Ayten, Asim Mustafa
    In retrospect, the role of scientific progress is of the utmost importance in the development and the current status of the universitites whose history is as old as the city life. The main determinants of the emergence of Enlightenment period have been the Reformation and the Renaissance movements in Europe. Thus, thoughts and ideas based on the mind instead of dogmas have made progress under the guidance of positivism and the city life has been indirectly affected from this development. The industrial revolution caused remodeling and changes in urban and spatial structure. Although educated and skilled labor force was not requested by the industry initially, that kind of force gained importance over time and the collaboration between industry and universities became inevitable. Until the years of 1940, Von Humboldt system, prevailing in Germany, changed and US system has become effective since 1945. During the years of 1960, universities became technology-based organizations and the institutions where scientific researches were conducted instead of the ones where only educational activities were carried out. Particularly, new settlements based on technology development regions attracted the attention. Within the order created by this relationship, different kinds of universities, research centers and spatial constructions were emerged either inside or outside the cities. In parallel with the growth of the cities, university buildings moved to the campuses outside the cities in accordance with the changing needs and new applications were made inside the cities and over the vast areas with different spatial typologies. In our study, campus site managements were examined in terms of environmental factors, logistics, traffic management, transportation and other criteria (population size, field size, space per person and etc.), sampled with a survey carried out on 22 universities and made an evaluation based on the responses taken by 17 universities. This study has shown that our universities have not got a large part of the criteria required to become a 3rd generation university. So as to compete with the other universities in the World, an approach with corresponding social, economic, and spatial dimensions which leaves an impression on the city, region, country and the whole World should be put into practice in the field of higher education.
  • Article
    Social Constructivism and Its Contributions to Explain the European Integration
    (Ankara Univ European Union Research Centre, 2015) Buyuktanir, Derya
    Social constructivist approach attained an important place within international relations discipline after 1980's. Constructivism focuses on social ontological elements such as inter-subjective meaning, norms, rules, institutions, discourse and communicative action. By this way it prevents these constructivist qualifications to be degraded to epistemological matter and also constitutes a starting point for the researches carried out on the European integration. Because, analyzing interaction between the subjects and social impacts shall assist to find the answers of the questions how and why European integration came to the current situation, to a great extent. Explaining this process within the scope of social constructivist approach rather than the integration theory shall provide to take many issues into consideration without getting far from the rational point of view.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Simultaneous Low Noise Radio Frequency Tone and Narrow Linewidth Optical Comb Generation From a Regeneratively Mode-Locked Laser
    (SPIE - Society of Photo-Optical Instrumentation Engineers, 2014-10-29) Ozdur, Ibrahim; Ozharar, Sarper; Delfyett, Peter J.
    A regeneratively mode-locked laser with simultaneous low noise radio frequency (RF) tone and optical comb generation is presented. The laser does not need any external RF signal and emits a pulse train at similar to 10 GHz repetition rate with a 1.5-ps optical pulse width after compression. The generated RF tone has a signal-to-noise ratio of 121 dB/Hz and an RF fluctuation of 10(-9) over 0.1 s. The optical frequency comb spacing is also at similar to 10 GHz and the optical comb tooth has a linewidth of <1 kHz. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
  • Article
    Citation - WoS: 7
    Citation - Scopus: 9
    Robust Tracking Controller for SEPIC Drivers
    (Inst Engineering Technology-IET, 2016-11) Ablay, G.
    The non-minimum phase, non-linear nature of the SEPIC (single-ended primary inductor converter) makes it very difficult to get robust operating conditions under load variations. Sliding-mode control method is utilised to design a robust controller for tracking control of SEPIC converters for various applications. The implementation of the method is illustrated with the use pulse-width modulation comparators in the control loop to preclude the risk of modulator saturation and to ease the operations. The performance of the SEPIC converter is investigated through numerical simulation and analogue electronics implementation to show the validity, robustness and feasibility of the proposed controller.
  • Article
    Rings With Variations of Flat Covers
    (Honam Mathematical Soc, 2019) Demirci, Yilmaz Mehmet; Turkmen, Ergul
    We introduce flat e-covers of modules and define e-perfect rings as a generalization of perfect rings. We prove that a ring is right perfect if and only if it is semilocal and right e-perfect which generalizes a result due to N. Ding and J. Chen. Moreover, in the light of the fact that a ring R is right perfect if and only if flat covers of any R-module are projective covers, we study on the rings over which flat covers of modules are (generalized) locally projective covers, and obtain some characterizations of (semi) perfect, A-perfect and B-perfect rings.
  • Article
    Citation - WoS: 34
    Citation - Scopus: 41
    Revisiting the Relationship Between Natural Gas Consumption and Economic Growth in Turkey
    (Taylor & Francis inc, 2015-01-12) Dogan, E.
    The objective of this study is to re-analyze the relationship between natural gas consumption (NGC) and economic growth (GR) for Turkey in a multivariate framework by including capital and labor as additional variables because several papers suggest that a bivariate model can suffer from omitted-variables bias. As compared to the findings of Isik (2010), who previously investigated the short-and long-run relationships between GR and NGC using a bivariate model, we find that the magnitude of the coefficient estimate of NGC become substantially smaller in the long-run and the sign of short-run estimate of NGC shift to negative after accounting for capital and labor as well. In addition to that covered by Isik (2010), we investigate the direction of causality between GR and NGC using the vector error correction model Granger causality approach, and reveal the evidence of feedback hypothesis for Turkey.
  • Article
    Citation - WoS: 4
    Relationship Between Neutrophil Gelatinase-Associated Lipocalin and Mortality in Acute Kidney Injury
    (Galenos Yayincilik, 2018-12-03) Kayaalti, Selda; Kayaalti, Omer; Aksebzeci, Bekir Hakan
    Objective: Almost half of intensive care patients are affected by acute kidney injury (AKI). The purpose of this study is to determine parameters that can be used for predicting of early (within 28 days) and late (within 90 days) mortality in patients who are followed-up with AKI in intensive care units. Materials and Methods: In this study, a dataset that contains 50 patients with AKI in intensive care units was used. This dataset contains blood urea nitrogen, creatinine, plasma and urinary neutrophil gelatinase-associated hpocalin (NGAL), lactate dehydrogenase, alkaline phosphatase and gammaglutamyl transpeptidase values of patients who were admitted to intensive care for various reasons and who developed AKI on the days 1, 3 and 7. In addition to these values, laboratory results such as serum electrolytes on day 1, blood gas; vital signs such as mean arterial pressure, central venous pressure; and demographic data were also recorded. Data mining techniques were applied to determine correlation between all of these data and mortality. Results: The threshold level of urinary NGAL on day 7 was determined to be 69 ng/mL, and strong correlation was found between this threshold level and early mortality. Similarly, the threshold level of plasma NGAL on day 7 was determined to be 150 ng/mL, and this was highly correlated with early mortality. Besides, strong correlation was also found between the difference in the urinary NGAL levels on day 1 and 7, and early mortality. Conclusion: In this study, plasma and urinary NGAL levels were found to be closely related to early mortality in patients who were followed-up with AKI in intensive care units. On the other hand, any parameter associated with late mortality was not found.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 4
    Rec. 2100 Color Gamut Revelation Using Spectrally Ultranarrow Emitters
    (SPIE - Society of Photo-Optical Instrumentation Engineers, 2017-11-22) Genc, Sinan; Uguz, Mustafa; Yilmaz, Osman; Mutlugun, Evren
    We theoretically simulate the performance of ultranarrow emitters for the first time to achieve record high coverage for the International Telecommunication Union Radiocommunication Sector BT. 2100 (Rec. 2100) and National Television System Committee (NTSC) color gamut. Our results, employing more than 130-m parameter sets, include the investigation into peak emission wavelength and full width at half maximum (FWHM) values for three primaries that show ultranarrow emitters, i.e., nanoplatelets are potentially promising materials to fully cover the Rec. 2100 color gamut. Using ultranarrow emitters having FWHM as low as 6 nm can provide the ability to attain 99.7% coverage area of the Rec. 2100 color gamut as well as increasing the NTSC triangle to 133.7% with full coverage. The parameter set that provides possibility to fully reach Rec. 2100 also has been shown to match with D65 white light by making use of the correct combination of those three primaries. Furthermore, we investigate the effect of the fourth color component on the CIE 1931 color space without sacrificing the achieved coverage percentages. The investigation into the fourth color component, cyan, is shown for the first time to enhance the Rec. 2100 gamut area to 127.7% with 99.9% coverage. The fourth color component also provides an NTSC coverage ratio of 171.5%. The investigation into the potential of emitters with ultranarrow emission bandwidth holds great promise for future display applications. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)