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Öğe Graphene for zirconia and titanium composites in dental implants: Significance and predictions(Springer Science and Business Media B.V., 2022) Özcan, Mutlu; Volpato, Claudia Angela Maziero; Hian, Lucas; Karahan, Billur Deniz; Cesar, Paulo FranciscoPurpose of Review: Graphene is introduced in dentistry as a material to be used in the fabrication or coating of dental implants due to its biocompatibility, ability to physically interact with biomolecules and very high surface area. This review highlights the current knowledge on the general properties of graphene, potential benefits especially when used in zirconia-based implants, as composite materials and coatings. Recent Findings: The literature reviewed showed a growing body of evidence supporting the use of graphene-based material, associated with titanium or zirconia as a coating or composite material that helps in cell viability, differentiation and proliferation, improving the bioactivity, osseointegration, physical, chemical and mechanical properties particularly zirconia. Graphene-based materials present great potential for biomedical applications especially when used in the form of nanostructured biological coatings that can be obtained through reproducible and economical processes. Summary: The use of graphene as a composite implant material or coating may have great potential for osseointegration and bone regeneration, providing that, features including hydrophilicity, protein adsorption capacity, oxygen content and effect of external parameters such as temperature, pH and ionic strength need further elucidations before they can be implemented as a coating or composite material for dental implants.Öğe Preface(Springer Science and Business Media Deutschland GmbH, 2022) Şen, Zekai; Erden, Caner; Öztemel, Ercan[Abstract Not Available]Öğe Discussion “A probability distribution for hydrological drought duration”(Elsevier B.V., 2021) Şen, ZekaiSong et al. (2021) deals with drought duration probabilistic modeling treatment based on Bernoulli-independent and lag-one Mar-kov process modeling procedures. However, calculations are based on percentages, not probabilities, and therefore the formulations are not hydrologically valid as drought length probabilities. The authors used the enumeration method for percentage calculations, not probability principles. Drought calculation has been established in the literature by scientific studies of different researchers based on probability principles (Feller, 1966; Yevjevich, 1963; S ?en, 1976, 1978, 1980). The presenta-tion by Song et al (2021) is not based on probabilistic principles such as mutually exclusive and independence principles for Bernoulli events. In order to distinguish the difference of the probability and percentage concepts, it is worth paying attention to the following points.Öğe Reservoirs for water supply under climate change impact-A review(Springer, 2021) Şen, ZekaiArid region water reservoirs have different characteristics and solutions from humid regions with the most water shortage in the world socio-economically. This paper outlines possible implementation methodologies, procedures and guidance for water storage in natural and artificial reservoirs for better operation and management rules taking into account the impacts of climate change. The literature is full of methodological applications regarding the impact of climate change on the hydro-meteorological records, but the same is not available in reservoirs (surface and underground), which is the scope of this paper. In addition, reservoir structures offer the necessary mitigation and adaptation activities against the effects of climate change to design, construct, maintain, operate or increase their existing capacity. To increase groundwater reservoir capacity in local aquifers, precipitation, associated flooding and flash flooding should be diverted to artificial groundwater recharges through precipitation and surface runoff harvesting activities. Definitions of fully or partially penetrating underground dams are also explained. The real groundwater feeding application is offered from the Kingdom of Saudi Arabia as arid region representative. Finally, a series of recommendations are presented for the future design and management of reservoirs.Öğe Trend analyses methodologies in hydro-meteorological records(Springer International Publishing AG, 2020) Almazroui, Mansour; Şen, ZekaiIn recent years, global warming and climate change impacts on hydro-meteorological variables and water resources triggered extensive focus on trend analyses. Especially, in historical records and climate change model scenario projections, trend feature searches help for better predictions prior to mitigation and adaptation activities. Each trend identification technique has a set of restrictive assumptions and limitations, but they are not cared for by many researchers. The major problem with trend research is that the researchers do not care for the basic assumptions of any methodology but use ready software to solve their problems. Among these assumptions, the most significant ones are the normal (Gaussian) probability distribution function (PDF) and serially independent structure of a given time series. It is the main objective of this review paper to present each trend identification methodology including classical ones with the new alternatives so that any researcher in need of trend analysis can have concise and clear interpretations for the choice of the most convenient trend method. In general, parametric, non-parametric, classical and innovative trend methods are explained comparatively including the linear regression, Mann-Kendall (MK) trend test with Sen slope estimation, Spearman's rho, innovative trend analysis (ITA), partial trend analysis (PTA) and crossing trend analysis (CTA). Pros and cons are given for each methodology. In addition, for improvement of serial independence requirement of the classical trend analyses, methods are introduced briefly by pre- and over-whitening processes. Finally, a set of recommendations is suggested for future research possibilities.Öğe Up-to-date statistical essentials in climate change and hydrology: A review(Inderscience Publishers Ltd, 2020) Şen, ZekaiIn climatology and hydrology probabilistic, statistical and stochastic analyses are frequently used tools for the identification of changes and variability within uncertainty domain. There are different statistical-based methodologies for climate change and hydrology data modelling, future simulation and projection studies. Although integro-differential conservation equations provide the dynamic basis, but due to uncertainty ingredients probabilistic and especially statistical calculation principles are panaceas for better solutions. In the literature, there are many articles, where the proper usages of the statistical methodologies are rather weak, incomplete or even to a certain extent not acceptable. The main reason might be in many cases use of ready software without knowing the rational, logical and practical background principles of the statistical methodologies with their validity of restrictive assumptions. There are numerous statistical methods with their special pros and cons. This review paper covers the main applications of statistical methods in climate change and hydrology studies.Öğe Water structures and climate change impact: A review(Springer, 2020) Şen, ZekaiClimate change impact started to play significant role since the last three decades almost in every aspects of life especially on meteorological and climatological events and their impacts on water resources, which are managed by engineering structures. Its effects on hydro-meteorological data are assessed by means of available methodologies, but the climate change impact of engineering water structures (dams, culverts, channels, wells, highways and their side drainages, levees, etc.) are not treated equally. This paper provides the review of the necessary adaptation, combat and mitigation activities against the climate change for protection, construction or augmentation of the engineering water structures design capacity. Additionally, land use practices and geomorphological changes also trigger the climate changes on the engineering water structures. The main aim of this paper is to present the impact of such changes on the engineering water structure capacity, operation and maintenance.Öğe Discussion of "Critical Values for Sen's trend analysis" by Richard H. McCuen(American Society of Civil Engineers (ASCE), 2020) Şişman, Eyüp; Güçlü, Yavuz Selim; Dabanlı, İsmailIt is well appreciated that the author of the original paper tried toavoid the qualitative subjectivity and proposed a quantitative approach for trend identification in a given hydrometeorology timeseries. He considered that there are not quantitative publicationson S¸ en’s innovative trend analysis (ITA) in the literature, whichis not correct, because there are a few papers published on the quantitative ITA trend estimation methodology.Öğe Innovative methodologies in renewable energy: A review(Wiley, 2019) Şen, ZekaiThis paper is concerned with innovative approaches to renewable energy sources computation methodologies, which provide more refined results than the classical alternatives. Such refinements provide additional improvements especially for replacement of fossil energy usages that emit greenhouse gas (GHG) into the atmosphere leading to climate change impact. Current knowledge gap among each renewable energy source calculation is rather missing fundamentals of plausible, rational, and logical explanations for the interpretation of results. In the literature, there are rather complicated and mechanically applicable methodologies, which require input and output measurement data match with missing physical explanations. The view taken in this review paper is to concentrate on quite plausible, logical, rational, and effectively applicable innovative energy calculation methodologies with simplistic fundamentals. For this purpose, a set of renewable energy methodological approaches is revisited with their innovative structures concerning solar, wind, hydro, current, and geothermal energy resources. With the increase in the renewable energy utilizations to combat the undesirable impacts of global warming and climate change, there is a need for better models that will include physical environmental conditions and data properties in the probabilistic, statistical, stochastic, logical, and rational senses leading to refined and more reliable estimations with application examples in the text. Finally, new research directions are also recommended for more refined innovative energy system calculations.Öğe Discussion on "Modeling karst spring hydrograph recession based on head drop at sinkholes" by Guangquan, Li, Nico Goldscheider, Malcom S. Field(Elsevier Science Bv, 2018) Şen, ZekaiGroundwater movement model development in karstic aquifers is very difficult due to the complexity of the solution cavities. The authors (Li et al., 2016) have proposed a square law model for expressing the discharge ratio in terms of hydraulic head ratio, with an exponent equal to 0.5. They have also provided the mathematical derivation in detail with application. It is noticed that the methodology can be expanded towards a better and refined solutions by consideration of the following explanations.
