TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7149

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Now showing 1 - 10 of 147
  • Article
    Experimental Investigation of Refractive Index Measurement of Common Solvents and Aqueous Solutions in the Infrared Wavelengths
    (2018) Yüksel, K.; İde, C
    We proposed and experimentally demonstrated a fast and simple technique to measure refractive index of liquids. A commercial Optical Time-Domain Reflectometer (OTDR) was implemented for interrogating sensor tips from a remote location. The system uses Fresnel reflected light from standard single mode fiber tips as sensing points without requiring any chemical coating, delicate fiber components, and/or sophisticated architecture at the sensor head. We reported new measurements of refractive indices of common solvents and solutions at both 1550 nm and 1625 nm. The precision of the proposed measurement system was found to be in the order of 10-4. The experimental results have been validated by the way of theoretical calculations.
  • Article
    Bir Kinestetik Haptik Cihazın Dinamik Analizi
    (2018) Ceccarellı, Marco; Maaroof, Omar W.; Dede, Mehmet İsmet Can
    Bu makalede R-CUBE mekanizması ve seri küresel bilek mekanizmasını temel alan bir hibrit-yapılı kinestetik haptik cihaz üzerinde durulmuştur. Cihaz noktasal teması kullanıcıya hissettirmesi için tasarlanmıştır. Dolayısı ile, sadece üç-boyutlu kuvvetler kullanıcıya R-CUBE mekanizması üzerinden iletilmiştir. Bu makale, mekanizmanın kabiliyetinin daha iyi anlaşılması ve ilerideki çalışmalarda haptik denetleyicisinde kullanılması için, RCUBE mekanizmasının yarı-statik kuvvet analizini, yerçekimi etkisi telafisi hesaplarını ve dinamik analizini sunmaktadır. Çıkarılan dinamik denklemler kullanılarak haptik uygulama senaryolarında gerekli eyleyici torkları incelenmiştir.
  • Article
    Pomza ve Nsdd-pomza ile Sabit Yataklı Kolon Reaktörde Metilen Mavisi Giderimi: Deneysel ve Modelleme Çalışması
    (2019) Balcı, Esin; Ökten, Hatice Eser; Genişoğlu, Mesut; Recepoğlu, Yaşar Kemal; Gören, Ayşegül Yağmur
    Nano sıfır değerlikli demir (nSDD) yüksek renk konsantrasyonlarına sahip tekstil atıksularının arıtımında ekonomik ve çevre dostu bir adsorban olarak ortaya çıkmaktadır. Ancak nSDD partikülleri sulu çözeltilerde elektrostatik etkileşimler sebebiyle kolayca topaklaşmakta ve bu da arıtma veriminin düşmesine neden olmaktadır. Dolayısıyla düşük maliyetli, doğal poröz yapıda ve ortalama 2m2/gr spesifik yüzey alanına sahip pomza, nSDD topaklaşmasını önleyici bir malzeme olarak kullanılabilir. Bu çalışmada sadece pomza ve pomzanSDD (ağırlıkça 9:1) karışımının kullanıldığı kolon reaktörde 25, 50, 75 ve 100 mg/L metilen mavisi konsantrasyonları için arıtma verimleri incelenmiştir. Pomzanın ve pomza-nSDD karışımının 100 mg/L metilen mavisi deneyindeki toplam kapasiteleri sırasıyla 2,8 ve 4,2 mg/g-adsorban olarak bulunmuştur. Özellikle düşük konsantrasyonlarda, pomza-nSDD karışımının arıtma performansını önemli ölçüde arttırdığı görülmüştür. Thomas modeli deneysel verilere uygulanmış ve modelin öngörü gücünün düşük konsantrasyonda yüksekken, yüksek konsantrasyonlarda ortalama olduğu kanısına varılmıştır.
  • Research Project
    Nanolifli yapıda, sinir büyüme faktörü yüklü mikro küreleri içeren jalatin bazlı doku iskelelerinin hazırlanması ve karakterizasyonu
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2014) Altınkaya, Sacide; Erdal, Esra; Büyüköz, Melda
    In living organisms most of the tissues have the capability of regeneration; on the other hand, this situation is different in mammalian adult neural cells since they loose their ability of proliferation. Compared to peripheral nervous system, central nervous system has restricted regeneration capability which results in trauma, stroke and neuropathology etc. The first studies for the regeneration of nervous system concentrated on the use of autographs, tissue transplanted from one part of the body to another in the same individual, but it has limitations including short-age. Another type of investigation was allograft, which is transplantation of cells isolated from cadavers to the patient, but this approach is also not suitable because of host immune rejection. A new hope to cure neurodegenerative diseases appeared with biomaterials and tissue engineering studies. In this study, it is aimed to develop a novel, nanofibrous scaffolds with the capability of controlled releasing neural growth factor loaded in microspheres. Nanofibrous and oriented scaffolds were prepared from gelatin by a combination of thermally induced phase separation (TIPS), porogen-leaching and molding techniques while alginate microspheres were produced in oil in water emulsion through cross linking of alginate with calcium ions. The bioactivity of the growth factor released from microspheres was determined using PC12 cell line, derived from rat adrenal medulla and differentiate when treated with nerve growth factor. The scaffolds including connected pores with a high porosity, nanofibrous structure which mimic the extracellular matrix and properties similar to natural brain tissure were produced. Compared to solid walled scaffolds, nanofibrous scaffolds allow attachment of cells without any change in their morphologies. Model protein Į-chemotripsin and bovin serum albumin used for protecting the activity of nerve growth factor were loaded in alginate microspheres with an encapsulation efficiency of 100 %. It was found that NGF loaded into microspheres can maintain its activity and it can even differentiate PC-12 cells in a shorter time compared to NGF directly added into cell culture medium.
  • Article
    Identification of Staphylococcus Aureus Cheese Isolates With Respect To Virulence Properties, Genetic Relatedness and Antibiotic Resistance Profiles
    (Özkan Özden, 2019) Kadiroğlu, Pınar; Korel, Figen; Ceylan, Çağatay
    The problems on identification of Staphylococcus aureus isolates from cheese samples wereinvestigated by phenotypic and genotypic tests in this study. Among 207 Staphylococcus spp.isolated from 31 cheese samples, 23 isolates that were Gram positive, catalase and slide coagulasepositive, with 1 isolate that was latex agglutination test negative showed different phenotypicproperties. Polymerase chain reaction (PCR) and quantitative PCR (qPCR) analyses showed thatDNase test and target genes (nuc, coa) regarded as gold standard regions for S. aureus were notfound to be unique for identification of S. aureus. The toxin genes (SEA-SEE) were not detected byPCR. Antibiotic resistance profiles of S. aureus isolates demonstrated that two isolates were resistantto penicillin G. This study showed that the unique phenotypic and genotypic test was not adequatefor identification of S. aureus isolates. There was no correlation between the presence of the nucgene and toxin genes. The presence of nuc gene which was used for detection of S. aureus was alsofound to be present in other Staphylococcus isolates. As a conclusion, the results revealed thatbiochemical tests could lead to false positive results for identification of S. aureus. The presence ofnuc gene is not correlated with the presence of toxin genes.
  • Article
    A Re-Design Project: Correction of an Outdoor Fitness Equipment’s Design According To Its Users’s Anthropometric and Biomechanical Data
    (2018) Kaya, Nazife Aslı; Erkarslan, Önder
    The aim of this study is to determine the anthropometric measurements of the users of outdoor fitness equipment and to re-design of an in-use outdoor fitness equipment according to these measurements. A total of 100 (50 male and 50 female) outdoor fitness equipment users, living in Eskisehir, Turkey, voluntarily participated in the study. Their ages ranged from 18 to 79 years and the mean of their ages were 31,2 (SD: 1,15277). The following human body dimensions were measured: stature, shoulder height, side-arm reach, fist (knuckle) height, forearm length, upper arm length, shoulder-fingertip length, knee height, malleolus height and hand length. The anthropometric measures of the adults and the outdoor fitness equipment’ dimensions were compared in order to identify any incompatibility between them. The data indicated a mismatch between the adults’ bodily dimensions and the outdoor fitness equipment available to them. Later on, in use fitness equipment’s motion output compared with biomechanical limits. Also, a mismatch was found between the motion output and biomechanical limits which might cause injuries. As these mismatches endanger public health, an outdoor fitness equipment, FE02 Stepper was re-designed according to its users’ anthropometric data and biomechanical limits as an example. 
  • Article
    Single Layer Res2h2: Stability, Raman Activity and Electronic Properties
    (Eskişehir Teknik Üniversitesi, 2018) Ünsal, Elif; Şahin, Hasan
    In this study, the structural, vibrational and electronic properties of the hydrogenated single layer of ReS2 are investigated byperforming the first principle calculations based on density functional theory. We found that the characteristic properties ofthe monolayer ReS2 can be manipulated upon the hydrogen functionalization. As the monolayer ReS2, the ReS2H2 hasdistorted 1T phase; however, the bonding in Re slab significantly varies with the hydrogenation. Our results demonstrate thatthe full-surface hydrogenation leads to an expansion in lattice and the Re4 tetramer-chains in the monolayer ReS2 areseparated into two dimers in the hydrogenated monolayer. It is calculated that the dynamically stable monolayer of ReS2H2has 26 Raman-active vibrational modes. Constant volume specific heat calculations are also performed and the resultsindicate that at high temperature, the monolayer ReS2 approaches to limit of 3R before the monolayer ReS2H2. By performingthe electronic band structure calculations, it is shown that when the ReS2 surface is fully hydrogenated, there occurs a directto indirect band gap transition and the semiconducting hydrogen-induced monolayer has a band gap of 0.74 eV.
  • Article
    The Ordering of Smokers’ Toothpaste Choice Criteria With Fuzzy Model
    (Atatürk Üniversitesi, 2019) Tarım, Ergün Alperay; Kuruoğlu Kandemir, Emel; Mevsim, Vildan
    Aim: There are some measures that smokers can cease or prevent damage caused by smoking. They may also choose some product features that may be more helpful to them like toothpaste selection etc. The preferences of smokers vary because of the variety of toothpaste in the market and a high number of products. The aim of this study is to determine the importance of toothpaste selection criteria in order to determine the decision and toothpaste selection. Material and method: Fuzzy DEMATEL model is used effectively in decision making problems. This model, which can rank the decision criteria in order of importance even for a single individual, is a more effective and important model in ordering the decision criteria of a large number of individuals. In this study, fuzzy DEMATEL model was used to determine the importance of toothpaste selection criteria. In this study, 7 toothpaste selection criteria were determined by data obtained by taking user and expert opinions. After the determination of criteria, the information form was applied to the model to show the criterion importance preferences of smokers. Results: According to the preferences of smokers, the selection criteria of toothpaste were placed in the order with the fuzzy DEMATEL model. The most important criteria is toothpaste package appearance, while the least of the 7 criteria is determined as the criteria that Sensation of Person. Conclusion: As a result, the toothpaste properties that the smokers would prefer, ie the toothpaste selection criteria are listed in importance. In other words, it is given the ranking of preference criteria for smokers when choosing toothpaste.
  • Article
    Sales History-Based Demand Prediction Using Generalized Linear Models
    (Süleyman Demirel Üniversitesi, 2019) Özenboy, Başar; Tekir, Selma
    It’s vital for commercial enterprises to accurately predict demand by utilizing the existing sales data. Such predictive analytics is a crucial part of their decision support systems to increase the profitability of the company.In predictive data analytics, the branch of regression modeling is used to predict a numerical response variable like sale amount. In this category, linear models are simple and easy to interpret yet they permit generalization to very powerful and flexible families of models which are called Generalized linear models (GLM). The generalization potential over simple linear regression can be explained twofold: First, GLM relax the assumption of normally distributed error terms. Moreover, the relationship of the set of predictor variables and the response variable could be represented by a set of link functions rather than the sole choice of the identity function. This work models the sales amount prediction problem through the use of GLM. Unique company sales data are explored and the response variable, sale amount is fitted to the Gamma distribution. Then, inverse link function, which is the canonical one in the case of gamma-distributed response variable is used. The experimental results are compared with the other regression models and the classification algorithms. The model selection is performed via the use of MSE and AIC metrics respectively. The results show that GLM is better than the linear regression. As for the classification algorithms, Random Forest and GLM are the top performers. Moreover, categorization on the predictor variables improves model fitting results significantly.
  • Article
    Effect of Substrate Concentration and Scale Up on the Polygalacturonase Production
    (Gıda Teknolojisi Derneği, 2019) Göğüş, Nihan; Tarı, Canan
    Pectinases have been used for many industrial applications since long time ago. The largest industrial application of these enzymes is in fruit juice and wine production for the extraction, filtration and clarification and for the maceration of fruits and vegetables. They work by enzymatic breaking down of the cell wall.In this study it was aimed to use the previously optimized shake flask media formulation in batch mode 1 L scale serial bioreactor system and 5 L scale in order to investigate the effects of substrate concentration and scale on PG activity and biomass production. In conclusion it was observed that average PG activity (101.29 U/ml) obtained in 5L scale bioreactor experiments was higher than the maximum PG activity (88.55 U/ml) at 40 g/L orange peel (OP) concentration obtained in the 1 L scale substrate concentration experiment. Furthermore,PG activity increased with an increase in substrate concentration except for 60 g/L orange peel concentration.