Ahievran University

Kırşehir, Turkey

Ahievran University

Kırşehir, Turkey
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Togay A.,Gazi University | Anil O.,Gazi University | Karagoz Isleyen U.,Kastamonu University | Ediz I.,Gazi University | Durucan C.,Ahievran University
Proceedings of the Institution of Civil Engineers: Structures and Buildings | Year: 2017

The static responses of timber-framed shear walls with and without openings of variable dimensions and locations were numerically investigated using the finite-element (FE) method. The lateral load resistance capacities and general load-displacement behaviours of the timber-framed shear walls were investigated. In the FE study, the frame elements were modelled as beams, plates were modelled as shells and nails were modelled as spring elements. The plastic behaviour of the materials was modelled using experimental stress-strain relationships of the materials. For timber frames and oriented strand board (OSB) panels, uniaxial stress-strain curves were experimentally obtained under tensile and compressive loading. From the experimental materials models it was found that spruce exhibited non-linear behaviour under both tensile and compressive stress. In contrast, the OSB sheathing layer used in the analyses exhibited non-linear behaviour under compressive stress and linear behaviour under tensile stress. The numerical results were verified using experimental load-deflection relationships obtained from a previous study. Good agreement was found between the analytical and experimental results. To further examine the applicability of the experimentally verified numerical model, four different timber-framed shear walls were simulated with FE models. © 2017, Thomas Telford Services Ltd. All rights reserved.

Muradoglu F.,Yuzuncu Yil University | Gundogdu M.,Yuzuncu Yil University | Yilmaz H.,Ahievran University
Italian Journal of Food Science | Year: 2011

In this study, we measured the concentrations of organic acids, phenolic compounds, sugars and vitamin C as well as the total antioxidant capacities of pomegranate genotype cultivars grown in the Siirt province of Turkey. Our analysis of organic acids found citric acid concentrations between 0.66-2.75 g/L and malic acid concentrations between 0.61-3.88 g/L. Our analysis of phenolic compounds found catechin concentrations between 0.88-2.96 g/L and chlorogenic acid concentrations between 0.04-0.43 g/L. Further analyses revealed fructose concentrations between 4.76-11.74 g/100 g and glucose concentrations between 2.98-8.43 g/100 g. In addition, the concentrations of vitamin C and the total antioxidant capacities contents ranged between 11.40-45.07 mg/L and 4.56-16.64 mmol/L, respectively.

Gundogdu M.,Yuzuncu Yidotlessl University | Muradoglu F.,Yuzuncu Yidotlessl University | Sensoy R.I.G.,The Ministry of Agriculture and Rural Affairs | Yilmaz H.,Ahievran University
Scientia Horticulturae | Year: 2011

This study was carried out to determine the organic acid content, phenolic compound content, sugar content, vitamin C (ascorbic acid) content and total antioxidant capacity of white mulberry (Morus alba L.), black mulberry (Morus nigra L.) and red mulberry (Morus rubra L.) fruits grown in Van province of Turkey. It was determined that the chief organic acid in these mulberry species was malic acid ranging from 1.32 to 4.47g 100g-1fw, followed by citric acid ranging from 0.39 to 1.08g 100g-1fw. Looking at the contents of phenolic compound, chlorogenic acid and rutin had come to the fore ranging from 0.12 to 3.11mgg-1fw and from 0.85 to 1.42mgg-1fw, respectively. Fruit glucose contents of the studied species were higher than their fructose contents, varying between 6.07 and 7.75g 100g-1fw. Total antioxidant capacity and vitamin C contents of the mulberry species ranged from 4.49 to 13.99μmol TEg-1fw and from 11.30 to 24.42mg 100g-1fw, respectively. © 2011 Elsevier B.V.

Koc A.,Balikesir University | Koc A.,Dumlupinar University | Koc A.,Erciyes University | Koc A.,Ahievran University | And 32 more authors.
International Urology and Nephrology | Year: 2015

Purpose: Varenicline is a new most effective drug for smoking cessation. Its effect on kidney functions remains unclear. This study purposed to investigate whether varenicline causes nephrotoxicity in rats. Methods: Fifteen rats were randomly assigned to three groups: control, 0.0125 mg kg−1 varenicline and 0.025 mg kg−1 varenicline (single dose for 3 days, i.p.). Before and after experimental period, serum neutrophil gelatinase-associated lipocalin, creatinine and urea levels were measured. Total oxidant and antioxidant status were measured in kidney homogenates. Histological examination was performed in kidney. Results: The nephrotoxic effects of varenicline were detected by histopathological and biochemical examinations in the varenicline treatment groups. No change was observed in the control group. Conclusions: These findings firstly indicate that a 3-day varenicline treatment causes nephrotoxic effects in rats. © 2015, Springer Science+Business Media Dordrecht.

Kosemen A.,Kocaeli University | Kosemen A.,Mus Alparslan University | Alpaslan Kosemen Z.,Kocaeli University | Alpaslan Kosemen Z.,TUBITAK - Marmara Research Center | And 8 more authors.
Solar Energy | Year: 2016

Inverted P3HT:PCBM based organic solar cells were fabricated by using Fe2+ doped TiO2 films as electron selective layer. Pure and Fe2+ doped TiO2 films were prepared by sol-gel method and the optical as well as the structural properties of the thin films were characterized by UV-Vis spectrophotometer and SEM. The concentration of Fe2+ was varied as 0.5%, 1%, 2% and 3% (w/w) in TiO2 layer and the influence of Fe2+ doping on the solar cell parameters were systemically investigated. Photocurrent density of the solar cells as increased from 8.75 to 13.8 mA/cm2, whereas the solar cell efficiency changed from 1.7% to 2.79% by using Fe2+ doped TiO2 electron selective layer. It was experimentally found and demonstrated that charge injection and selection in the TiO2 interlayer was improved by doping of Fe2+ atoms in the TiO2. © 2016.

Aydin O.,Middle East Technical University | Aydin O.,AhiEvran University | Korkusuz F.,Hacettepe University | Korkusuz P.,Hacettepe University | And 4 more authors.
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2015

Osteoarthritis (OA) is a degenerative joint disease, which has no complete treatment with medication yet. Intraarticular hyaluronan (HA) injection can decrease pain and modify the natural course of OA. This study was designed to provide long term delivery of an MMP (matrix-metalloproteinase) inhibitor agent-doxycycline, together with matrix regenerative agent-chondroitin sulfate for treating OA which progress with matrix degenerations. Doxycycline (D) and doxycycline-chondroitin sulfate (D-CS) loaded poly-ε-caprolactone (PCL) microspheres (MS) were prepared as intraarticular delivery systems. Bio-effectiveness of developed microspheres was first evaluated with three-dimensional in vitro model of OA where both MS showed significant reduction in MMP-13 levels compared to untreated OA-chondrocytes at 15 and 24 days. Significant decrease was observed in GAG release into the media for both D MS and D-CS MS treated groups at 15 and 24 days. Second, the microspheres were injected to rabbit knee in hyaluronan (HA) to evaluate the effectiveness of the treatment. Radiographic scores of D MS and D-CS MS groups improved after 8 weeks when compared to OA group. Mankin-Pitzker histological scores similarly showed improvement with D MS and D-CSMS groups when compared to OA group. Ex vivo hardness tests of cartilages demonstrated superior hardness values with both doses of D-CSMS compared to OA group. D MS showed promising improvement of OA in histology results. Although, both MS groups had similar effects on cells in the in vitro model, D-CSMS had a positive contribution on all in vivo treatment outcomes and showed potential as a new strategy for treatment when applied to OA knee joints. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1238-1248, 2015. © 2014 Wiley Periodicals, Inc.

Kilic S.,AhiEvran University | Ozturk F.,The Petroleum Institute | Sigirtmac T.,The Coskunoz Metal Form | Tekin G.,The Coskunoz Metal Form
Journal of Iron and Steel Research International | Year: 2015

The effects of pre-strain and baking temperature on bake hardening behaviour of TWIP900CR steel were investigated. The results reveal that the bake hardening process contributes to an increase in yield strength up to 65 MPa at the baking temperature of 200 °C. The difference in yield strength between baking temperatures of 170 and 200 °C is almost insignificant. It is clearly observed that baking at a high temperature does not result in a significant increase in yield strength. For a reasonable bake hardening, a good combination of pre-strain and baking temperature is necessary. Besides, the toughness of the material is found to decrease with increasing pre-strain. © 2015 Central Iron and Steel Research Institute.

Gundogdu M.,Yuzuncu Yil University | Yilmaz H.,Ahievran University
Scientia Horticulturae | Year: 2012

In this study, organic acid and phenolic compound contents and antioxidant capacities of some standard Turkish pomegranates and formerly selected 5 promising local pomegranate genotypes in Pervari region of Siirt Province (Gündoĝdu, 2006) were determined. With respect to antioxidant capacities, the highest value (14.67mmolTEL-1) was determined in Silifke aşisi pomegranate fruits among all examined cultivars and genotypes. Considering the organic acid contents of pomegranate juices, citric acid was identified to be the predominant organic acid and the highest value (2.1823gL-1) was identified in 56PER19 genotype. No acetic acid content was identified in the examined cultivars and genotypes. In terms of phenolic compound contents, the highest value of gallic acid (6.361gL-1) was identified in çevlik pomegranate cultivar. The findings of study indicated that pomegranate cultivars and genotypes have important phytonutrients. Rather than the content of energy; the rich content of minerals, vitamins, organic acids and phenolic compounds make pomegranate an important source material for fruit processing industry. © 2012 Elsevier B.V.

Ozen G.,Ahievran University | Akbulut M.,Selcuk University | Artik N.,Ankara University
Journal of Food Process Engineering | Year: 2011

In this research, traditional Turkish delight (lokum) was colored with black carrot juice concentrate, and the variations in anthocyanin content, during storage at different temperatures (12, 20 and 30C) for 5-month periods, were observed by spectrophotometer and high-performance liquid chromatography. Analysis of kinetic data suggested a first-order reaction for the degradation of black carrot anthocyanins in Turkish delight. Degradation rates of anthocyanins of black carrot increased with increasing temperature. It was determined that the degradation rate of black carrot anthocyanins during the storage period at 12C increased faster than that of the other temperatures (20 and 30C). The k values for 12, 20 and 30C were found to be 6.91 × 10 -3, 4.21 × 10 -3and 9.21 × 10 -3/day, respectively. Effects of pH on the thermal stability of black carrot anthocyanins were also determined. Results showed that the stability of anthocyanins decreased as the pH value increased. Increase in pH values correlated well with the decrease in anthocyanin content of the samples during storage. In all of the samples, redness (a*) decreased during the storage at all temperatures; however, lightness (L*) increased. PRACTICAL APPLICATIONS Most of commercial anthocyanins used as a colorant in foods are obtained from fruits or vegetables such as: red grape, elderberry, blackcurrant, blackberry, raspberry, black chokeberry, red cabbage, black carrot, purple corn, red radish and purple sweet potato. Turkish delight (lokum), one of the most popular traditional food products in Turkey, is a famous Turkish desert known all over the world. Lokum is produced by using sugar, water, starch, citric acid, aromatic compounds, dried fruits and natural colorant. The color of foods, which is one of the initial properties noticed in foods, is one of the most important quality parameters affecting consumers. Because of consumer anxiety over the safety of synthetic food colorants, the demand for natural food colorants has increased. Particularly, there is an increasing request for natural red food colorants as alternatives to the most commonly used synthetic red colorant. Therefore, the availability and the suitability of black carrot juice concentrate as a natural colorant instead of synthetic colorants which are considered to have some negative properties for human health was investigated by this work. © 2009 Wiley Periodicals, Inc.

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