Authors:İrfan Kaya Abstract: The objectiveof the present study is to characterize the mechanical behavior of laminatedmetal composites (LMCs) that consist of commercially pure titanium and 1100aluminum layers which were ultrasonically consolidated. Ultrasonic consolidation is a low temperatureprocess used to fabricate layered solid metal structures. Tensile tests ofTi-Al laminated composites (in 3, 5, and 7 bilayer configurations) wereperformed at four various temperatures (25 ºC, 100 ºC, 200 ºC, and 300 ºC)using strain rate of 0.017 /s. The effect of temperature, sonotrode travel direction,and number of layers on the material behavior were discussed on the basis ofuniaxial tensile test results. The ultimate tensile strength and yield strengthis found to decrease with increasing temperature. In general, high strainvalues were obtained in Y samples compared to X samples. The maximum strainvalue was 0.42 at 300 °C temperature in the 5 bilayer Y sample. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Nuray Güy Abstract: NiFe2O4magnetic nanoparticles were solvothermally prepared. NiFe2O4magnetic nanoparticles were functionalized with gallic acid and then papainimmobilized on NiFe2O4 functionalized with gallic acid. The obtained samples werecharacterized and the activities of free and immobilized papain were studied.Immobilized papain showed higher and more effective activity than free papain. Thisimmobilized papain retained about 75.5% of its initial activity after 8 weeksof storage at 4 °C in sodium phosphate buffer (0.1 M, pH 6.5), while the freetrypsin protected 30.5% of its initial activity during the same condition.Furthermore, the immobilized papain protected approximately 51% of its initialactivity following the times of ten sequential reuse. Finally, the microwaveassisted digestion of bovine serum albumin was carried out for 15 s withmatrix-assisted laser desorption/ionization mass spectrometry by using free andimmobilized papain. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Ersin Önem; Ali Yorgancıoğlu, Onur Yılmaz Abstract: Valoneaextract is a natural tannage widely applied in leather industry which isproduced via conventional hot water extraction method. On the otherhand moreenvironmental friendly methods have started to be used in extraction technologyrecently. Present paper reports on the effect of different extraction methodson the properties of valonea extracts. For this purpose, conventional solventextraction (CSE) (methanol/water mixture), supercritical CO2 (scCO2)extraction and pressurized fluid extraction (PFE) (water/CO2 binarysystem) techniques have been employed on valonea and the obtained extracts havebeen characterized. Molecular weight of the tannins was determined by gelpermeation chromatography (GPC), particle size was examined by MalvernZetasizer instrument, chemical structure by Fourier Transform InfraredSpectroscopy (FTIR). Tannin content was also examined and the results were comparedwith commercial valonea extract (CVT). The results showed that especiallyparticle size of the tannins was affected by the applied extraction method andthe smallest particle size was obtained by PFE method as 505.3 nm compared tocommercial tannin as 983.0 nm of average particle size. PFE method was alsoprovided more uniform extract according to the polydispersity index values. GPCand FTIR analyses showed slightly differences on the characteristics of tannins. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Zeliha Demirel; Esra Imamoglu, İrem Deniz, Meltem Conk Dalay Abstract: The preservation of microalgaein a stable state is a fundamental requirement in pharmaceutical, agricultural,environmental sciences and different industries. Cryopreservation is widelystabilized for achieving long-term storage and has been applied to anincreasingly diverse range of microalgae and cell cultures. The continuous storageof actively growing microalgae strains by routine serial subculture isrelatively time-consuming and this technique has possible contamination risks.In this study, the optimization of cryopreservation process was carried out fortwo different Chlorella strainsusing response surface methodology (RSM) with three factors (cryoprotectantconcentration, incubation time and cryopreservation time) including 19 runs. Theoptimal cell viability of C. zofingiensiswas found at the dimethyl sulfoxide (DMSO) concentration of 12.89% at the incubationtime of 8.14 min and with the cryopreservation time of 93.45 day, while C.saccharophila was found at theDMSO concentration of 12.86 % at the incubation time of 7.99 min and atcryopreservation time of 95.17 day. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Osman Günaydın; Abdurrahman Özbeyaz, Mehmet Söylemez Abstract: Some challenging studies are experimentally appliedfor characterizing parameters in Proctor compaction tests. Compression of afill is mechanically done in Compaction process. Compaction is a physicalprocess which gets the soil into a dense state. Improving the shear strengthand decreasing the compressibility and permeability of the soil can be donewith this physical process. Support Vector Machine (SVM) is a popular methoddue to its performance today. This method is commonly employed in theregression analysis as well as being used in the classification process. Inthis study, SVM was employed to predict of compaction parameters (maximum dryunit weight and optimum moisture content) without making any experiments in a soillaboratory. In the study, more than a hundred compaction data collected fromthe small dams in central Anatolia region was employed. In the study, R errorsare satisfied (0.92 and 0.89) for SVM models. Consequently, the proposedregression analysis with SVM is useful for model design of the projects in wherethere are limitations as financial and temporal. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Tanju Kahraman Abstract: Inthis work, we examine null quaternionic rectifying curves and null quaternionicsimilar curves in Minkowski space E1^3. Also, we defined null quaternionic (1,3)-Bertrand partnercurves in E1^4. Thus, we have characterizations between curvatures of thesecurves in Minkowski spaces. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Mehmet Akkaş; Serkan Islak, Cihan Özorak Abstract: Cu-xTiC (x=0, 1, 5, 10 and 15wt.%) composites were prepared by hot pressing (HP) technique. Themicrostructure, corrosion and wear features of Cu matrix composites (CMCs) wereinvestigated. The wear surfaces and microstructure of the CMCs were analyzedusing SEM-EDS. Phases of samples were identified by means of XRD. Hardnessmeasurements of the composites were made using a microhardness device. Hardnesstests showed that the hardness tends to increase with increasing TiC amount. Wearproperties of the CMCs were determined using ball-on-disc method. Significantdecreases in wear rates were observed in composites reinforced with TiC. The corrosionproperties of the composites were characterized by potentiostatic polarizationtest. Corrosion results showed that the corrosion resistance of the compositesdecreased with the increase of TiC content in Cu. Among the composites, Cu-1% TiC has the bestcorrosion resistance. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Serhan Eker Abstract: In this paper, SeibergWittenlike equations without selfduality are defined on dimensional manifolds. Then, nontrivial and flat solutions are given to them on . Finally, on realdimensional Kähler manifolds a global solution to these equation isobtained for a given negative and constant scalar curvature. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Zülküf Demir Abstract: Drilling is a widely used production method, having a broad range of applicationstaking part in machining operations. The length of the cutting edge of thedrill causes variations in cutting speed, resulting in undesired outputs. Inorder to decrease this adverse impact in drilling, selecting higher pointangles is an obligation, associated with three different kinds of feed ratesand spindle speeds. The aim of this study is to investigate the effect of feedrate, spindle speed, and point angle on the fluctuation size in thrust forcebesides the effect of the fluctuation size in thrust force on the surfaceroughness, tool wear and chip morphology. In conclusion, while higher pointangles provided optimum outputs such as lower fluctuation size in thrust force,less tool wear, better surface quality and continuous chip form, the effect offeed rate and spindle speed on these outputs varied depending on each other.With the stability in fluctuation size in thrust force, less tool wear tookplace, and better surface quality and continuous chip form were achieved. However,due to the effect of vibrations, higher fluctuation size in thrust force causedundesired outputs, such as poor surface quality, more tool wear, removal chipin short and brittle form during the drilling operations. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Müjde Durukan Gültepe; Zekai Tek Abstract: Inthis study, we investigate nematic-isotropic phase transitions in liquidcrystals using fractionally generalized form of the Maier-Saupe Theory (MST).MST is one of the mean-field theories commonly used in the nematic liquidcrystals which proved to be extremely useful in explaining nematic-isotropicphase transitions. Fractionally obtained results compared with those of theexperimental data for p-azoxyanisole (PAA) in the literature. In this context,the dependence of fourth rank order parameters on second rank order parametersis handled by being a measure of fractality of space. It is observed that thevariation of second-rank and fourth rank order parameters versus temperatureare in accordance with some values of fractal dimensions. As a result, we canconclude that there is a close relationship between temperature and fractional derivativeorder parameters. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Betül Akın; Burcu Çetin, Nüket Akanıl Bingöl Abstract: The aim of this experiment is to develop a protocol to establish the in vitro propagation potential of Lythrum salicaria L (purple loosestrife).Seeds of L. salicaria were germinatedand grown in Murashige Skoog (MS) medium for 30 days. At the end of 30 days, shoot tips of L. salicaria were cultured on MS medium supplemented with differentcombinations and concentrations of 6-benzylaminopurine (BAP; 1, 2 and 3 mg/L) and1-naphthaleneacetic acid (NAA; 0, 0.1 and 0.5 mg/L). Regenerated shoots were transferredto MS supplemented with varying concentrations of different auxins: NAA (0.5and 1 mg/L) and indole-3-butyric acid (IBA; 0.5 and 1.0 mg/L) for rooting. Amongthe cytokinins investigated, BAP indicated the best response to initiate shootelongation and multiple shoot formation alone. The highest number of shoot perexplant (37±3.38) was obtained in MS medium with 1 mg/L BAP. Although, thehighest shoot length (3.1 cm ± 0.48) was found on medium with 1 mg/L BAP+0.5 mg/LNAA, there were no statistically differences among all types of medium.Percentage of rooting, shoot length and root length were altered significantlywith different concentrations of NAA and IBA. Thus, shoot length (9.5 cm±0.46),root length (4.1 cm±0.13) and the percentage of rooting (100%) increasedsignificantly with a concentration of 1 mg/L NAA. It was concluded that MS medium with 1 mg/LNAA has been superior for root development compared to other hormoneconcentrations. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Merve Akçay; Mehmet Atak Abstract: Energy is an increasing need arising from the existence of mankind.Electricity is one of the most important secondary energy sources. Obtaining ofelectricity from fossil sources leads to negative consequences such as climatechange and environmental pollution. In addition, fossil resources are not endless. For this reason, theimportance of renewable energy sources that are sustainable and not harmful tothe environment such as fossil fuels is increases for electricity generation.In this study, electricity generation with solar power is considered. There are somefactors to achieve efficiency in the projects of obtaining electric energy withsolar energy. One of the most important of these factors is to choose the rightplace. There are multiple criteria that affect the correct location selection. Multiplecriteria decision making methods are suitable for site selection studies wherethere are many criteria. In this study, Konya, Karaman, Burdur, Antalya,Mersin, Van which are fortunate cities in Turkey in terms of sunbathing areselected as alternatives. A hybrid AHP and TOPSIS method is used to select thebest alternative according to the sub-criteria determined under the economic,technical, social and geographical main criteria. Criterion weights are foundby the AHP method and alternatives are ranked with the TOPSIS method. Theresult of the study is thatMersin is the best alternative for solar power plant and Mersin is followed byKaraman, Burdur, Konya, Van and Antalya respectively. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Dilek Ünal; İnci Tüney Kızılkaya Abstract: In this study the protection ability of polyamines onPhotosystem II (PSII), the proline content of the cells and necrosis formationinduced by Ultraviolet-A irradiation were studied. Although 24 h Ultraviolet-Aexposure decreased the photosynthetic quantum yield (Fv/Fm) ratio in Physcia semipinnata (J. F. Gmel.) Moberg,thalli that treated with 1 mM polyamine, especially spermidine and spermine,were slightly influenced by the UV-A exposure. It was also found that spd andspm treated samples had lower proline content than putrescine (put)-treated samples.Moreover, It was found that the samples that were treated with spd and spm hadlower percentage of DNA damage than put-treated samples and non-treated groups.In this study, Ultraviolet-A induced DNA damage detected by acridineorange/ethidium bromide staining assay. The DNA damage in thalli of P. semipinnatawas detected in situ in phycobiont layer after 24 h of Ultraviolet-A exposure,in contrast, polyamine-treated samples had a lower rate of necrotic cells. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:İrfan Uçkan Abstract: This work has processed, analyzed and regulated thedata comprising surface temperature, sunshine duration and global solarradiation for the period of 1993 to 2007 in Van (38.28oN, 43.20oE). Hourly, monthly and annual variations ofsolar radiation are calculated. Furthermore, the annual variations of sunshineduration, surface temperature and clearness index are also analyzed. Annualaverage maximum global solar radiation was seen in 2000 with 19.68 MJ/m2day andthe trend of yearly series of global solar radiation increases from 1993 to2007. The highest hourly and monthly values are 3260 kJ/m2h and 28.72 MJ/m2day,respectively. Besides, daily monthly and annual of clearness index, hourlyfrequency distribution and sunshine duration are discussed and the solarradiation and the annual clearness index are correlated. Consequently, the Vanregion has a high solar energy potential and a high frequency of cleardaylight. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Bülent Ergönül; Fatih Kalyoncu, Ilgaz Akata Abstract: In this study, it was aimed to determine themicrobiological attributes of 8 wild edible mushrooms (Agrocybe cylindracea, Amanita cecilae, Boletus reticulatus, Coprinus comatus,Cantharellus cibarius, Lactarius deliciosus, Suillus collinitus and Tricholoma myomyces) collected fromdifferent parts of Anatolia, Turkey. In order to determine the microbiologicaland hygienic situation, E.coliO157:H7, Listeria monocytogenes, yeastand molds, total mesophilic aerobic bacteria count, total coliforms, lacticacid bacteria, Salmonella spp., Staphylococcus aureus and Clostridium botulinum were investigatedfor mushroom species. According to obtained data, microbiological and hygieniccharacteristics of wild edible mushrooms are acceptable. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Bükem Bilen; Nural Pastaci Ozsobaci, Fatma Ates Alkan, Mehmet Burcin Unku Abstract: The aim of our study is toevaluate the capability of acoustic microscopy with a high frequency transducerfor visualization of cells. Human kidney embryonic (HEK293) cells were observedby scanning acoustic microscope (SAM). HEK293 cells cultured on cover glasseswere kept in cell culture plates. A transducer with 320 MHz center frequencyand a spot size of 4.0 µm was incorporated into SAM. Two-dimensional acousticimages were obtained successfully to identify the morphology and the acousticproperties of HEK293 cells and the acoustic impedance of HEK293 cells wasmeasured as 1.65 ±0.02 MRayl. The same cells on cover glasses were observed also with invertedmicroscope. The results in this study indicate that scanning acousticmicroscopy can be used for the determination of elastic properties of cells,therefore for cellular mapping and molecular imaging, since it can create verysharp images of HEK293 cells with a high frequency transducer. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Savaş Selahattin Ateş; Haşim Kafalı, Hasan Lik Abstract: Aircraft maintenancetechnician is a profession that needs to be licensed according to internationalaviation organizations. Aircraft Maintenance Training standards are awardedaccording to the standards set by EASA Part 66/ 147 as determined by the EuropeanAviation Agency (EASA). It has been published in SHY66/ 147 by the DirectorateGeneral of Civil Aviation (DGCA) in Turkey, which contains documents similar toEASA. Aircraft Maintenance Technician examinations (SHY66 Module Exams) can becarried out by SHY147 Basic Training Institutions which is authorized by theDGCA. DGCA has granted Anadolu University as the authority to make exams inTurkey. The study was carried out in order to determine the exam systemperceptions of candidates who entered the SHY66 Module Examinations, whichprovides Air Vehicle Maintenance Training in Turkey. In the first part of thestudy, with international and national standards for aircraft techniciantraining was provided with literature. In the second part, survey dimensionsdeveloped to measure the test system perception are explained. In the thirdpart, the questionnaire designed to determine the perceptions of the candidatesof the aircraft maintenance technicians who entered SHY66 Module Examinationwas analyzed. The survey was completed by 506 technician candidates. With theresults of the analysis, suggestions have been made to develop examinations forSHY66 Module Examinations. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Özlem Şahin; Çerkez Ağayeva Abstract: In this study, the static(based on Base of Aircraft Data) and the dynamic aircraft fuel consumptionmodels are constructed for the descent phase. Therefore, two flighttrajectories, from Istanbul to Frankfurt (LTBA- EDDF) and from Los Angeles toNew York (KLAX-KJFK), are chosen in order to analyze the appropriaterelationships between the different parameters such as altitude, speed andtime. A medium range aircraft is taken into consideration while developinglinear and quadratic models. For LTBA- EDDF, fuel consumption as 200 kg, 193,89kg and 193,58 kg are found for BADA, linear and quadratic models, respectively.It corresponds to about a 3 % difference from BADA. Furthermore, for KLAX-KJFK,approximately a 5% difference is obtained. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Alper Kürşat Uysal Abstract: This study analyses the effectiveness of six textfeature selection methods for automatic classification of drug reviews writtenin English using two different widely-known classifiers namely Support VectorMachines (SVM) and naïve Bayes (NB). In the study, a recently published publicdataset namely Druglib including drug reviews in English was utilized in theexperiments. For evaluation, Micro-F1 and Macro-F1 success measures were used.Also, 3-fold cross-validation is preferred to perform a fair evaluation. The featureselection methods used in the study are Distinguishing Feature Selector (DFS), InformationGain (IG), chi-square (CHI2), Discriminative Features Selection (DFSS), ImprovedComprehensive Measurement Feature Selection (ICMFS), and Relative DiscriminationCriterion (RDC). However, experiments were performed using two settings inwhich stemming was applied and not applied. Experiments indicated that ICMFSfeature selection method is generally superior to the other feature selectionmethods according to the overall highest Micro-F1 and Macro-F1 scores achievedon drug reviews. While the highest Micro-F1 score was achieved with thecombination of NB classifier and ICMFS feature selection method, the highestMacro-F1 score was achieved with the combination of NB classifier and DFSSfeature selection method. The highest Micro-F1 and Macro-F1 scores were achievedfor the cases that stemming algorithm was not applied. PubDate: Mon, 31 Dec 2018 00:00:00 +030
Authors:Candan akca Akca; Ayşegül Ekmekçi Körlü, Mustafa Ateş Abstract: Natural zeolites are one of the most examined natural minerals. By meansof new studies conducted on zeolites, new areas of usage are being discoveredday by day. It is possible to produce modified zeolites that having manyvariable functions by using the ion exchange capability of zeolite. In thisstudy 100% cotton fabrics was used in the trials. The natural zeolite, used inthe trials, was provided from Enli Madencilik A.Ş. and originated from theManisa-Gördes region. The manufacturing of Zn-Zeolite was performed. And thenthe Zn-Zeolite were applied to cotton fabrics. The characteristics of thecotton fabrics treated with zinc-loaded antibacterial zeolite are analyzed inthis article. PubDate: Mon, 31 Dec 2018 00:00:00 +030
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