Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 10Citation - Scopus: 10Influence of Calcium Acetate Concentration in Electrolyte on Tribocorrosion Behaviour of Mao Treated Titanium(MDPI Multidisciplinary Digital Publishing Institute, 2021) Sousa, Luis; Mendes, Ana Rita; Pinto, Ana Maria Pires; Toptan, Fatih; Alves, Alexandra CruzTi-based materials are widely used for dental and orthopaedic implant applications due to their adequate mechanical properties, corrosion behaviour and biocompatibility. However, these materials are biologically inert and display poor wear resistance. In one of the most studied processes that aims to overcome these drawbacks, Ti surfaces are often covered by anodic oxide films with the incorporation of bioactive agents such as Ca and P. Although there are several works on the tribocorrosion behaviour of MAO-treated Ti surfaces, the influence of electrolyte composition on the corrosion kinetics under sliding is yet to be fully understood. In the present work, anodic oxide films were produced on cp-Ti surfaces with different calcium acetate concentrations in the electrolyte. Tribocorrosion behaviour was investigated by reciprocating sliding tests performed in 8 g/L NaCl solution at body temperature, under potentiostatic conditions. The results showed that higher concentrations of calcium acetate had a detrimental effect on tribocorrosion kinetics, however, they resulted in less mechanical damage due to alterations in the topography and structure of the MAO layer.Article Citation - WoS: 17Citation - Scopus: 17Developing Wound Dressings Using 2-Deoxy To Induce Angiogenesis as a Backdoor Route for Stimulating the Production of Vascular Endothelial Growth Factor(MDPI Multidisciplinary Digital Publishing Institute, 2021) Dikici, Serkan; Yar, Muhammad; Bullock, Anthony J.; Shepherd, Joanna; Roman, Sabiniano; MacNeil, Sheila2-deoxy-D-Ribose (2dDR) was first identified in 1930 in the structure of DNA and discovered as a degradation product of it later when the enzyme thymidine phosphorylase breaks down thymidine into thymine. In 2017, our research group explored the development of wound dressings based on the delivery of this sugar to induce angiogenesis in chronic wounds. In this review, we will survey the small volume of conflicting literature on this and related sugars, some of which are reported to be anti-angiogenic. We review the evidence of 2dDR having the ability to stimulate a range of pro-angiogenic activities in vitro and in a chick pro-angiogenic bioassay and to stimulate new blood vessel formation and wound healing in normal and diabetic rat models. The biological actions of 2dDR were found to be 80 to 100% as effective as VEGF in addition to upregulating the production of VEGF. We then demonstrated the uptake and delivery of the sugar from a range of experimental and commercial dressings. In conclusion, its pro-angiogenic properties combined with its improved stability on storage compared to VEGF, its low cost, and ease of incorporation into a range of established wound dressings make 2dDR an attractive alternative to VEGF for wound dressing development.Article Comparison of Length Scale Parameterization Methodologies(MDPI Multidisciplinary Digital Publishing Institute, 2020) Tuna, Faruk; Bingöl, FerhatAtmospheric stability has been studied for decades. There are several methodologies that evolved over the years. In this study, a special experimental meteorological mast that has been erected to a complex site has been used to calculate dimensionless Obukhov length (zeta), dimensionless momentum (phi m), and heat coefficients (phi h). The results are compared with the ones from average value approaches: Richardson number, flux-profile (F-P) relations, and wind shear exponent methods. The results show that the estimated zeta values, using the bulk Richardson number, get along well with the reference zeta within the neutral and stable regimes. F-P relations and wind shear exponent methods result in the best agreement for stable and neutral regimes. Nevertheless, average oriented methods are not reliable for the other regimes.Article Citation - WoS: 18Citation - Scopus: 23On the Effect of Modified Carbohydrates on the Size and Shape of Gold and Silver Nanostructures(MDPI Multidisciplinary Digital Publishing Institute, 2020) Yazgan, İdris; Gümüş, Abdurrahman; Gökkuş, Kutalmış; Demir, Mehmet Ali; Evecen, Senanur; Sönmez, Hamide Ayçin; Toprak, Muhammet S.Gold (Au) and silver (Ag) nanostructures have widespread utilization from biomedicine to materials science. Therefore, their synthesis with control of their morphology and surface chemistry have been among the hot topics over the last decades. Here, we introduce a new approach relying on sugar derivatives that work as reducing, stabilizing, and capping agents in the synthesis of Au and Ag nanostructures. These sugar derivatives are utilized alone and as mixture, resulting in spherical, spheroid, trigonal, polygonic, and star-like morphologies. The synthesis approach was further tested in the presence of acetate and dimethylamine as size- and shape-directing agents. With the use of transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) absorption spectroscopy techniques, the particle size, shape, assembly, aggregation, and film formation characteristics were evaluated. NPs' attributes were shown to be tunable by manipulating the sugar ligand selection and sugar ligand/metal-ion ratio. For instance, with an imine side group and changing the sugar moiety from cellobiose to lactose, the morphology of the Ag nanoparticles (NPs) transformed from well dispersed cubic to rough and aggregated. The introduction of acetate and dimethylamine further extended the growth pattern and morphological properties of these NPs. As examples, L5 AS, G5AS, and S5AS ligands formed spherical or sheet-like structures when used alone, which upon the use of these additives transformed into larger multicore and rough NPs, revealing their significant effect on the NP morphology. Selected samples were tested for their stability against protein corona formation and ionic strength, where a high chemical stability and resistance to protein coating were observed. The findings show a promising, benign approach for the synthesis of shape- and size-directed Au and Ag nanostructures, along with a selection of the chemistry of carbohydrate-derivatives that can open new windows for their applications.Article Citation - WoS: 30Citation - Scopus: 44A Review on Computational Modeling Tools for Mof-Based Mixed Matrix Membranes(MDPI Multidisciplinary Digital Publishing Institute, 2019) Keskin, Seda; Alsoy Altınkaya, SacideComputational modeling of membrane materials is a rapidly growing field to investigate the properties of membrane materials beyond the limits of experimental techniques and to complement the experimental membrane studies by providing insights at the atomic-level. In this study, we first reviewed the fundamental approaches employed to describe the gas permeability/selectivity trade-off of polymer membranes and then addressed the great promise of mixed matrix membranes (MMMs) to overcome this trade-off. We then reviewed the current approaches for predicting the gas permeation through MMMs and specifically focused on MMMs composed of metal organic frameworks (MOFs). Computational tools such as atomically-detailed molecular simulations that can predict the gas separation performances of MOF-based MMMs prior to experimental investigation have been reviewed and the new computational methods that can provide information about the compatibility between the MOF and the polymer of the MMM have been discussed. We finally addressed the opportunities and challenges of using computational studies to analyze the barriers that must be overcome to advance the application of MOF-based membranes.Article Citation - WoS: 19Citation - Scopus: 27Reactive Power Capability Model of Wind Power Plant Using Aggregated Wind Power Collection System(MDPI Multidisciplinary Digital Publishing Institute, 2019) Sarkar, Moumita; Altın, Müfit; Sorensen, Poul E.; Hansen, Anca D.This article presents the development of a reactive power capability model for a wind power plant (WPP) based on an aggregated wind power collection system. The voltage and active power dependent reactive power capability are thus calculated by using aggregated WPP collection system parameters and considering losses in the WPP collection system. The strength of this proposed reactive power capability model is that it not only requires less parameters and substantially less computational time compared to typical detailed models of WPPs, but it also provides an accurate estimation of the available reactive power. The proposed model is based on a set of analytical equations which represent converter voltage and current limitations. Aggregated impedance and susceptance of the WPP collection system are also included in the analytical equations, thereby incorporating losses in the collection system in the WPP reactive power capability calculation. The proposed WPP reactive power capability model is compared to available methodologies from literature and for different WPP topologies, namely, Horns Rev 2 WPP and Burbo Bank WPP. Performance of the proposed model is assessed and discussed by means of simulations of various case studies demonstrating that the error between the calculated reactive power using the proposed model and the detailed model is below 4% as compared to an 11% error in the available method from literature. The efficacy of the proposed method is further exemplified through an application of the proposed method in power system integration studies. The article provides new insights and better understanding of the WPPs' limits to deliver reactive power support that can be used for power system stability assessment, particularly long-term voltage stability.Article Citation - WoS: 5Citation - Scopus: 7Inertia Dependent Droop Based Frequency Containment Process(MDPI Multidisciplinary Digital Publishing Institute, 2019) Das, Kaushik; Altın, Müfit; Hansen, Anca D.; Sorensen, Poul E.Presently, there is a large need for a better understanding and extensive quantification of grid stability for different grid conditions and controller settings. This article therefore proposes and develops a novel mathematical model to study and perform sensitivity studies for the capabilities of different technologies to provide Frequency Containment Process (FCP) in different grid conditions. A detailed mathematical analytical approach for designing inertia-dependent droop-based FCP is developed and presented in this article. Impacts of different droop settings for generation technologies operating with different inertia of power system can be analyzed through this mathematical approach resulting in proper design of droop settings. In contrast to the simulation-based model, the proposed novel mathematical model allows mathematical quantification of frequency characteristics such as nadir, settling time, ROCOF, time to reach the nadir with respect to controller parameters such as gain, droop, or system parameters such as inertia, volume, of imbalance. Comparative studies between cases of frequency containment reserves (FCR) provision from conventional generators and wind turbines (WTs) are performed. Observations from these simulations are analyzed and explained with the help of an analytical approach which provides the feasible range of droop settings for different values of system inertia. The proposed mathematical approach is validated on simulated Continental Europe (CE) network. The results show that the proposed methodology can be used to design the droop for different technology providing FCP in a power system operating within a certain range of inertia.Article The Sustainability of an Urban Ritual in the Collective Memory: Bergama Kermesi(MDPI Multidisciplinary Digital Publishing Institute, 2019) İnceköse, ÜlküBergama Festival, locally known as Bergama Kermesi, is an annual festival which dates back to 22 May 1937 in the city. It came into existence as a result of Ataturk's intention to introduce this, an extraordinary town with its historical and cultural properties, and promote it internationally. The Festival is an important element in the collective memory of the city. Initially, it was a civic event, a device in the formation process of the Turkish Republic. However, now, it is a civil event for national and international representatives, and a festival that allows locals and guests from different social, economic, and cultural backgrounds to mix freely and equally for a certain period. In the course of the Festival, the public buildings and the open spaces of the town become places of activity and entertainment. Parks, stadiums, the town square, and streets function as spaces for a variety of activities. Looking back at its 81-year history, one can notice some important changes in the Festival's cultural and social practices, from an earlier state-dominated character into the current more publicly oriented one. This article studies the change of Bergama Festival as an invented tradition' into an element of the collective memory in town from the perspective of different public affairs that it introduces. In this regard, the article will also show how an urban ritual can maintain its sustainability by keeping itself fresh in the social life.Article Citation - WoS: 64Citation - Scopus: 109Irrigation of World Agricultural Lands: Evolution Through the Millennia(MDPI Multidisciplinary Digital Publishing Institute, 2020) Angelakis, Andreas N.; Zaccaria, Daniele; Krasilnikoff, Jens; Salgot, Miquel; Bazza, Mohamed; Roccaro, Paolo; Fereres, Elias; Baba, AlperMany agricultural production areas worldwide are characterized by high variability of water supply conditions, or simply lack of water, creating a dependence on irrigation since Neolithic times. The aim of this paper is to provide an overview of the evolution of irrigation of agricultural lands worldwide, based on bibliographical research focusing on ancient water management techniques and ingenious irrigation practices and their associated land management practices. In ancient Egypt, regular flooding by the Nile River meant that early agriculture probably consisted of planting seeds in soils that had been recently covered and fertilized with floodwater and silt deposits. On the other hand, in arid and semi-arid regions farmers made use of perennial springs and seasonal runoff under circumstances altogether different from the river civilizations of Mesopotamia, Egypt, India, and early dynasties in China. We review irrigation practices in all major irrigation regions through the centuries. Emphasis is given to the Bronze Age civilizations (Minoans, Egyptians, and Indus valley), pre-Columbian, civilizations from the historic times (e.g., Chinese, Hellenic, and Roman), late-Columbians (e.g., Aztecs and Incas) and Byzantines, as well as to Ottomans and Arabs. The implications and impacts of irrigation techniques on modern management of water resources, as well as on irrigated agriculture, are also considered and discussed. Finally, some current major agricultural water management challenges are outlined, concluding that ancient practices could be adapted to cope with present challenges in irrigated agriculture for increasing productivity and sustainability. © 2020 by the authors.Article Citation - WoS: 2Citation - Scopus: 3Can Tube Tunnel Crossings Relieve Urban Congestion Problems? Izmir Tube Tunnel Project Proposal Under Scrutiny(MDPI Multidisciplinary Digital Publishing Institute, 2019) Duvarcı, Yavuz; Yiğitcanlar, TanBuilding underwater tube tunnel crossings to ease the urban congestion problems has become a popular approach for many cities across the globe. London, New York, Istanbul, Hamburg, Sydney and Brisbane are among these cities. However, the effectiveness and externalities of these expensive mega urban infrastructures have also been questioned widely among urban, transport and environmental planning scholars. Given the international popularity of the topic, this study places a new tube tunnel crossings project from Izmir, Turkey under the microscope. In this heuristic simulation study, policy-on scenarios were tested to determine possible impacts of the underwater tube tunnel-crossing project. The traffic impacts are discussed using simulations assigning the initial origin-destination data. The results of the study revealed that, given the two locations, outer and inner locations over the dagger-shape bay, the capacity increments on the bridge links and the links around the periphery highway did not bring any effective solutions beyond some minor improvements. The findings disclosed that the ineffectiveness of the tube tunnel crossing might be due to the excessive congestion happening all over the downtown area, which clogs the passageways to the bridge. The paper highlights the limitations of the tube tunnel-crossing project, emphasises the need for comprehensive investigations before committing to the project and advocates the emphasis to be actually given for sustainable mobility.