Sule I.,Bartin University
Sensors and Actuators, A: Physical | Year: 2011
In this study, the defects observed on the Chenille yarn, (a member of the class of fancy yarns), have been converted into digital signals through an experimental system composed of an optoelectronic sensor. The effect of the production properties of the yarn (material, yarn count, pile density) and the wavelength of the light transmitter (LED) on the signal-to-noise ratio (SNR) of the sensor signal have been investigated. The parameters affecting the amplitude of the noise signal and the amplitude of the defect signal have been identified using the Fresnel formulae and the formulae established in geometrical optics. Mathematical formulae presenting the dependence of the amplitude of the sensor signal on the radiant intensity emerging from the transmitter in the experimental setup (IF), the geometrical parameters of the measurement system (distance between the yarn and the light transmitter, the numerical aperture of the slot) and the production parameters for the yarn (pile yarn diameter, core yarn diameter, pile density, defect length) have been obtained. The transmission indexes for wool, polyester, viscose and acrylic Chenille yarn of the same yarn count (3 Nm) and for 4.2 Nm acrylic and 5.5 Nm polyester Chenille yarn have been determined experimentally for the peak wavelengths of 467 nm, 489 nm, 520 nm, 590 nm, 640 nm and 850 nm in the light transmitter of the optoelectronic measurement device. The dominant parameter in the determination of the SNR value of the sensor system has been concluded to be the pile density of the yarn. When yarn of the same material with increasing yarn counts via decreasing pile densities (3-4.2 Nm acrylic and 3-5.5 Nm polyester) is used, the SNR values decrease with increasing the amplitude of the transmittance voltage. SNR is determined by the optical characteristics of the yarn when they are of the same yarn count, twist level and pile density. In this study, the SNR values of the acrylic yarns have been determined to be lower than those of the polyester and viscose yarns of the same pile density and the same yarn count due to their higher transmittance properties. It has been obtained that the changes observed in the transmittance characteristics in response to varying wavelengths of the transmitter become more important in the identification of shorter length defects with high SNR. © 2011 Elsevier B.V. All rights reserved.
Bolat I.,Bartin University
European Journal of Forest Research | Year: 2014
Reducing the canopy cover (e.g., forest thinning) is one of the most commonly employed forest silvicultural treatments. Trees are partially removed from a forest in order to manage tree competition, thus favoring the remaining and often the most valuable trees. The properties of the soil are affected by forest thinning as a result of changes in key microclimatic conditions, microbial communities and biomass, root density, nutrient budgets and organic matter turnover. The aim of this study was to determine the soil microbial biomass C, N and respiration (basal respiration) in a black pine (Pinus nigra Arn. subsp. pallasiana) forest in the Mudurnu district of Bolu Province (Western Black Sea Region, Turkey). Whereas forest thinning was found to cause increases in the soil temperature, microbial biomass C and N and organic C, it was found to decrease the soil moisture, basal respiration and metabolic quotient (qCO2). As expected, soil organic C exhibited a strong impact on soil microbial biomass C, N and basal respiration. It was concluded that the influence of forest thinning on the microbial biomass and soil respiration was the combined result of changing microclimatic conditions and soil properties, such as forest litter, soil temperature, soil moisture, soil pH and soil organic matter. © 2013 Springer-Verlag Berlin Heidelberg.
Aksakal O.,Atatürk University |
Ucun H.,Bartin University
Journal of Hazardous Materials | Year: 2010
This study investigated the biosorption of Reactive Red 195 (RR 195), an azo dye, from aqueous solution by using cone biomass of Pinus sylvestris Linneo. To this end, pH, initial dye concentration, biomass dosage and contact time were studied in a batch biosorption system. Maximum pH for efficient RR 195 biosorption was found to be 1.0 and the initial RR 195 concentration increased with decreasing percentage removal. Biosorption capacity increased from 6.69mg/g at 20°C to 7.38mg/g at 50°C for 200mg/L dye concentration. Kinetics of the interactions was tested by pseudo-first-order and pseudo-second-order kinetics, the Elovich equation and intraparticle diffusion mechanism. Pseudo-second-order kinetic model provided a better correlation for the experimental data studied in comparison to the pseudo-first-order kinetic model and intraparticle diffusion mechanism. Moreover, the Elovich equation also showed a good fit to the experimental data. Freundlich and Langmuir adsorption isotherms were used for the mathematical description of the biosorption equilibrium data. The activation energy of biosorption (Ea) was found to be 8.904kJ/mol by using the Arrhenius equation. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the study also evaluated the thermodynamic constants of biosorption (ΔGo, ΔHo and ΔS). The results indicate that cone biomass can be used as an effective and low-cost biosorbent to remove reactive dyes from aqueous solution. © 2010 Elsevier B.V.
Caliskan H.,Bartin University
Materials and Design | Year: 2013
Mechanical and tribological properties of hard coatings can be enhanced using boron as alloying element. Therefore, multicomponent nanostructured boron based hard coatings are deposited on cutting tools by different methods at different parameters. Different mechanical and tribological properties are obtained after deposition, and it is a difficult task to select the best coating material. In this paper, therefore, a systematic evaluation model was proposed to tackle the difficulty of the material selection with specific properties among a set of available alternatives. The alternatives consist of multicomponent nanostructured TiBN, TiCrBN, TiSiBN and TiAlSiBN coatings deposited by magnetron sputtering and ion implantation assisted magnetron sputtering at different parameters. The alternative coating materials were ranked by using three multi-criteria decision-making (MCDM) methods, i.e. EXPROM2 (preference ranking organization method for enrichment evaluation), TOPSIS (technique for order performance by similarity to ideal solution) and VIKOR (VIšekriterijumsko KOmpromisno Rangiranje), in order to determine the best coating material for cutting tools. Hardness (H), Young's modulus (E), elastic recovery, friction coefficient, critical load, H/E and H3/E2 ratios were considered as material selection criteria. In order to determine the importance weights of the evaluation criteria, a compromised weighting method, which composes of the analytic hierarchy process and Entropy methods, were used. The ranking results showed that TiBN and TiSiBN coatings deposited at given parameters are the best coatings for cutting tools. © 2013 Elsevier Ltd.
Pekgozlu I.,Bartin University
Journal of Luminescence | Year: 2013
Pure and Pb2+ doped LiSr4(BO3)3 materials were prepared by a solution combustion synthesis method. The phase analysis of all synthesized materials were determined using the powder XRD. The synthesized materials were investigated using spectrofluorometer at room temperature. The excitation and emission bands of LiSr4(BO 3)3: Pb2+ were observed at 284 and 328 nm, respectively. The dependence of the emission intensity on the Pb2+ concentration for the LiSr4(BO3)3 were studied in detail. It was observed that the concentration quenching of Pb2+ in LiSr4(BO3)3 is 0.005 mol. The Stokes shifts of LiSr4(BO3)3: Pb2+ phosphor was calculated to be 4723 cm-1. © 2013 Elsevier B.V.
Pekgozlu I.,Bartin University
Journal of Luminescence | Year: 2013
M2Mg(BO3)2:Sm3+ (M:Sr and Ba) phosphors were synthesized by a solution combustion synthesis method followed by heating of the precursor combustion ash at 900 °C in air. The synthesized materials were characterized by using the powder XRD. The emission and excitation spectra of these materials were measured at room temperature with a spectrofluorometer. Both Sr2Mg(BO3)2:Sm 3+ and Ba2Mg(BO3)2:Sm3+ phosphors emit a strong in orange-red region. It was observed that the optimum concentration of Sm3+ in Sr2Mg(BO3)2 and Ba2Mg(BO3)2 are 0.01 and 0.04 mol, respectively. Finally, the relation between the photoluminescence properties of Sm3+ and host compositions was discussed in detail. © 2012 Elsevier B.V. All rights reserved.
Gencel O.,Bartin University
Fire and Materials | Year: 2012
Aggregates typically constitute 70 to 80 wt% of concrete, and therefore their type, size, and structure play an essential role in modifying the properties of concrete. When concrete is used for shielding nuclear applications, temperature is also a key factor. This study investigates the effects of elevated temperatures (25 °C, 200 °C, 400 °C, 600 °C, and 800 °C), heating durations (1, 2, and 3 h), and cooling regimes (air, and water cooling) on mechanical properties of concrete containing different proportions of hematite. A sample of plain concrete was produced for comparison purposes by using river sand, crushed sand, and crushed aggregates. Replacement ratios of 15%, 30%, 45%, and 60% were used for hematite aggregates. The cement content and water-cement ratio were 450 kg/m 3 and 0.38, respectively. Slump values of fresh concretes as well as unit weight, compressive strength, flexural strength, splitting tensile strength, and elasticity modulus values of hardened concrete were determined. The addition of hematite into concrete seems to improve its mechanical properties, and hematite concretes have better thermal stability at elevated temperatures than plain concrete does. Copyright © 2011 John Wiley & Sons, Ltd.
Caliskan H.,Bartin University
Measurement: Journal of the International Measurement Confederation | Year: 2014
Micro-abrasion wear test is a widely used method in measurement of abrasive wear resistance of thin hard coatings. During the test, selection of test parameters has great importance in determination of the wear behavior of the material under investigation correctly. Therefore, in this study, the effect of test parameters on the micro-abrasion behavior of CrN coating was investigated by the fixed-ball micro-scale abrasion test and modeled by response surface methodology. The coating was deposited on AISI D2 cold work tool steel using industrial cathodic arc evaporation system. The wear tests have been performed using SiC abrasive slurry. Analysis of worn craters was conducted by scanning electron microscope (SEM). It was found that the models obtained from ANOVA tables for wear volume and wear rate of CrN coating are significant and have high correlation coefficients. The rotation speed has higher influence on the wear volume of CrN coating, whereas the normal load has higher influence on the wear rate. The higher normal load increases the wear volume and decreases the wear rate. The effect of rotation speed changes according to the value of applied speed. Grooves take place by two-body abrasion in all of the craters obtained at different rotation speed and normal load values. Depth of parallel grooves in CrN coating and AISI D2 substrate decreases with the normal load and with the rotation speed. © 2014 Elsevier Ltd. All rights reserved.
Polat K.,Bartin University
Journal of Medical Systems | Year: 2012
In this paper, attribute weighting method based on the cluster centers with aim of increasing the discrimination between classes has been proposed and applied to nonlinear separable datasets including two medical datasets (mammographic mass dataset and bupa liver disorders dataset) and 2-D spiral dataset. The goals of this method are to gather the data points near to cluster center all together to transform from nonlinear separable datasets to linear separable dataset. As clustering algorithm, k-means clustering, fuzzy c-means clustering, and subtractive clustering have been used. The proposed attribute weighting methods are k-means clustering based attribute weighting (KMCBAW), fuzzy c-means clustering based attribute weighting (FCMCBAW), and subtractive clustering based attribute weighting (SCBAW) and used prior to classifier algorithms including C4.5 decision tree and adaptive neuro-fuzzy inference system (ANFIS). To evaluate the proposed method, the recall, precision value, true negative rate (TNR), G-mean1, G-mean2, f-measure, and classification accuracy have been used. The results have shown that the best attribute weighting method was the subtractive clustering based attribute weighting with respect to classification performance in the classification of three used datasets. © 2011 Springer Science+Business Media, LLC.
Kucuk Y.,Bartin University
Tribology Transactions | Year: 2012
In this study, the abrasiveness property of blast furnace slags emerging as a waste material in the production of crude iron was investigated. The abrasive slurry wear (ASW) method was used for experiments. For abrasiveness tests, oxides (Al2O3, Al2O3-13% TiO2, Al2O3-40%TiO2, Cr2O3), including ceramics, which were coated on the AISI 1040 medium carbon steel surface via the plasma spray-coating method, were used. The aim of this experimental investigation was to determine the effects of the same parameters, such as abrasive particle size, mud concentration, rotational speed, and sliding distance, on abrasiveness. The effects of the investigated parameters on abrasiveness are given in order of the most affected to the leastas rotational speed, coating materials, abrasive particle size, and sliding effects, respectively. Abrasion resistance was increased as a result of an increase in the hardness of coating for abraded material. According to sample scanning electron microscopy (SEM) micrographs, plastic deformation and microcrack abrasion mechanisms were determined. It was determined that blast furnace slag has a characteristic that causes abrasion on ceramics coatings. In addition, it was observed that blast furnace slag has quite a high abrasion effect on substrates. The best wear resistance was observed in the coating of Cr2O3 and other magnitudes of wear resistance from high to low for coatings were determined as Al2O3, Al2O3-13% TiO2, and Al2O3-40%TiO2, respectively. Copyright © Society of Tribologists and Lubrication Engineers.