Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(67)
- Merdan, Mehmet(59)
- Duran, Celal(49)
- Ozdes, Duygu(46)
- Kaygusuz, Abdullah(45)
- Demir, Selim(37)
- Turan, Ibrahim(37)
- Karsli, Orhan(36)
- Öztürk, Serkan(35)
- Dokuz, Abdurrahman(34)
- Araz, Onur(32)
- Kandemir, Raif(31)
- Kulakaç, Nurşen(29)
- Sipahi, Ferkan(29)
- Arslan, Mehmet(27)
- Baltaci, Cemalettin(27)
- Baltacı, Cemalettin(27)
- Kurt, Kemal(27)
- Topal, Fevzi(27)
- Gücer, Mehmet Ali(25)
- Peker, Iskender(25)
- Aydin, Faruk(24)
- Bayrakdaroglu, Serdar(24)
- Maden, Nafiz(24)
- Ozturk, Samet(24)
- Vural, Alaaddin(24)
- Yolcu, Halil(24)
- Yücel, Cem(24)
- Aliyazicioglu, Yuksel(23)
- Kankal, Murat(23)
- Reis, Hatice Catal(23)
- Ürkek, Bayram(23)
- Günen, Mehmet Akif(22)
- Kurnaz, Muammer(22)
- Topal, Meryem(22)
- Karimullah, Suud Sarim(21)
- Uysal, Ibrahim(21)
- Ashyralyyev, Charyyar(20)
- Aydin, Aydanur(20)
- Bayraktar, Alemdar(20)
Yayınlar
- DüzeltmeYalnız künye2017Scopus SJRQ1Retraction notice to “Regional sustainable water and energy development projects: A case of Southeastern Anatolia Project (GAP) in Turkey” [Renew Sustain Energy Rev 16/2 (2011) 1146–1156](S136403211100551X)(10.1016/j.rser.2011.11.015)
Akpinar, A.; Kaygusuz, K.
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The authors have plagiarized part of a paper that had already appeared in Renewable Energy, Volume 39 (2012), Pages 17–23, DOI: 10.1016/j.renene.2011.08.006. Although the authors were contacted for a reaction, we were unsuccessful in obtaining a response. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.
- MakaleAçık Erişim2017Scopus SJRQ3Morus rubra extract induces G1 cell cycle arrest and apoptosis in human lung and prostate cancer cells
Turan, Ibrahim; Demir, Selim; Kilinc, Kagan; Aliyazicioglu, Yuksel; Alver, Ahmet; Misir, Sema; Yaman, Serap Ozer; Akbulut, Kubra; Mentese, Ahmet; Deger, Orhan
Objective: Cancer is one of the most deadly types of disease and evasion from apoptosis and unstoppable cell proliferation are accepted as its distinctive features. Many studies have evaluated the cytotoxic effect of different Morus species but, there is no study about cytotoxic effect of Morus rubra. In this study we aimed to evaluate phenolic composition, antioxidant properties and cytotoxic effect of acidified dimethyl sulfoxide extract of M. rubra (AMRE). Method: Antioxidant properties, phenolic composition and cytotoxic effect of AMRE were determined using spectrophotometric methods, HPLC, and MTT assay, respectively. Then, mechanisms of cytotoxic effect of AMRE on human prostate (PC-3) and lung (A549) cancer cells were examined in regard to cell cycle, apoptosis and mitochondrial membrane potential using flow cytometric methods. Results: Total phenolic content and reducing power values were 11.9 mg gallic acid equivalents and 42.9 mg trolox equivalents per g sample, respectively. Ascorbic and gallic acid were detected in AMRE as major antioxidant compounds. We determined that AMRE increased cell cycle arrest at G1 phase and exhibited apoptotic features via decreasing mitochondrial membrane potential in both prostate and lung cancer cells. Conclusion: These findings demonstrate that M. rubra extract can affect the behavior of human prostate and lung cancer cells in vitro conditions, and this effect now needs to be investigated in vivo.
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İncele - MakaleAçık Erişim2017Scopus SJRQ3Cytotoxic effect of Laurocerasus officinalis extract on human cancer cell lines; [Laurocerasus officinalis ekstraktının İnsan kanser hücre serileri üzerindeki sitotoksik etkisi]
Demİr, Selim; Turan, İbrahim; Demİr, Feyza; Ayazoğlu Demİr, Elif; Alıyazicioğlu, Yuksel
Laurocerasus officinalis Roem. (Prunus laurocerasus L.), also locally known as “karayemis or taflan”, is a popular black summer fruit belonging to the genus Prunus and the family Rosaceae. L. officinalis exhibits numerous biological activities, such as anti-inflammatory, antinociceptive, antioxidant, neuroprotective, and antidiabetic effects. The aim of this study was to determine the total phenolic content and cytotoxic effect of dimethyl sulfoxide extract of L. officinalis (DEL). The total phenolic content and cytotoxic effect of DEL were investigated using the Folin-Ciocalteu method and thiazolyl blue tetrazolium bromide (MTT) assay, respectively. Total phenolic content value was 33.7±0.13 mg gallic acid equivalent per g sample. DEL exhibited selective cytotoxic effects against four human cancer (lung, colon, liver, and cervix) cell lines. The most selective cytotoxic effect of the extract was observed in colon cancer cells (IC50=265.2±8.1 μg/mL) compared to normal fibroblast cells. These data demonstrate that L. officinalis extract exhibits selective cytotoxicity towards some cancer cells. Further studies are now needed to clarify the molecules involved and their mechanisms.
AtıfScopus17WoS21OpenAlex34TR Dizin14
İncele - MakaleAçık Erişim2017Scopus SJRQ3Effect of the Simultaneous Variation in Blade Root Chord Length and Blade Taper on Helicopter Flight Control Effort
Oktay, Tugrul; Sal, Firat
In this study, the effect of simultaneous variation in blade root chord length and blade taper on the control effort of helicopter flight control system (i.e., FCS) of a helicopter is investigated. Therefore, helicopter models (i.e., complex, control-oriented, and physics-based models) including the main physics and essential dynamics are used. The effect of simultaneous variation in the blade root chord length and blade taper (i.e., in both chordwise and lengthwise directions dependently) on the control effort of an FCS of a helicopter and also on the closed-loop responses is studied. Comparisons in terms of the control effort and peak values with and without variations in the blade root chord and blade taper changes are carried out. For helicopter FCS variance-constrained controllers, specific output variance-constrained controllers are beneficial.
AtıfScopus13WoS11OpenAlex16İncele - MakaleAçık Erişim2017Scopus SJRQ3Diversity and ecology of benthic diatoms in karagöl lake in karagöl-Sahara national park (Şavşat, Artvin, Turkey)
Akar, Bülent; Şahin, Bülent
The main goal of this study is to determine the composition, diversity and ecology of benthic diatoms in Karagöl Lake in Karagöl-Sahara National Park. Monthly sampling (from sediments, stones and aquatic plants in littoral zone of the lake) taken in three consecutive years revealed 57 diatom taxa with Gomphonema and Pinnularia being the most abundant species while other genera are represented with three or fewer species. Lindavia ocellata was the most dominant taxon in the samplings examined throughout the whole study. The values of diversity and evenness indices are high during the spring and early summer. Based on cluster analysis for monthly samples of epipelic diatom, there are two different groups at the lowest similarity level. The associations between August 2010 and September 2010 months are the most significant with 86.02%. The organism number of epipelic diatoms showed positive correlation (P<0.01) with dissolved oxygen, while negative correlation (P<0.05) with temperature. Detailed floristic and ecological examination of the benthic diatom communities has not been carried out before this study in this lake. Therefore, this study is the first to our knowledge towards revealing aquatic benthic diatom biodiversity of Karagöl-Sahara National Park and provides basis for future investigations.
AtıfScopus7WoS9OpenAlex4İncele - MakaleYalnız künye2017Scopus SJRQ2Morus Rubra Extract Induces Cell Cycle Arrest and Apoptosis in Human Colon Cancer Cells Through Endoplasmic Reticulum Stress and Telomerase
Demir, Selim; Turan, Ibrahim; Aliyazicioglu, Yuksel; Kilinc, Kagan; Yaman, Serap Ozer; Ayazoglu Demir, Elif; Arslan, Ayse; Mentese, Ahmet; Deger, Orhan
Many studies have reported cytotoxic effects of different Morus species, but there have been only limited studies on the cytotoxic effect of Morus rubra. The aims of this study were to evaluate the cytotoxic effect of dimethyl sulfoxide extract of M. rubra and to investigate, for the first time, its probable cytotoxic activity in human colon cancer (WiDr) cells, together with the mechanism involved. The cytotoxic activity of extract was determined using MTT assay. The mechanism involved in the cytotoxic effect of extract was then evaluated in terms of apoptosis, and the cell cycle using flow cytometry, mitochondrial membrane potential (MMP) was investigated using the fluorometric method, and expression levels of telomerase and C/EBP homologous protein (CHOP) were investigated using reverse-transcription PCR (RT-PCR). M. rubra extract exhibited moderate selective cytotoxicity on colon cancer cells compared with fibroblast cells. Extract induced cell cycle arrest at the G1 phase and apoptosis via reduced MMP in WiDr cells. Additionally, M. rubra extract significantly repressed telomerase and induced CHOP expressions in WiDr cells. Our results demonstrate that targeting telomerase and endoplasmic reticulum stress represents a promising strategy in colon cancer therapy, and M. rubra may have considerable potential for development as a novel natural product-based anticancer agent.
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İncele - MakaleYalnız künye2017Scopus SJRQ2Stability Estimates for Solution of Neumann-Type Overdetermined Elliptic Problem
Ashyralyyev, Charyyar
This paper addresses estimation of the solution of inverse problem for the elliptic type equation with second kind boundary conditions and Neumann-type overdetermination at the interior point. We prove various estimates for the solution of this identification problem. Then, the first order accuracy stable difference scheme is studied. The stability, almost coercive stability, and coercive stability inequalities for its solution are obtained. The theoretical results can be applied to investigate identification problems for multidimensional elliptic equation with different kind of boundary conditions.
AtıfScopus28WoS18OpenAlex26İncele - MakaleYalnız künye2017Scopus SJRQ2Characterization of Grape Molasses/Sesame Paste/Honey Blends: Multiple Response Optimization of Some Physicochemical, Bioactive, Viscoelastic and Sensory Properties
Karaman, Safa; Yilmaz, Mustafa Tahsin; Ozturk, Gokturk; Yuksel, Ferhat; Toker, Ömer Said; Dogan, Mahmut
In this study, blends of grape molasses, sesame paste and honey were prepared at different ratios according to the mixture design and some physicochemical, rheological, bioactive and sensory properties of final blends were studied to create the optimum formulation for the final product. The results showed that the mixture components had significant change on the studied parameters (P < 0.05). Sugar composition of samples changed significantly by the addition of grape molasses and honey which resulted an increase in fructose and glucose. Grape molasses increase in the blend provided a significant increment in total phenolic content and antiradical activity. The blends had viscoelastic character and the mixtures containing higher honey showed more viscous behavior. The highest complex viscosity values were recorded for the blends of sesame paste and honey. Regression models having quite high determination of coefficients (R2 > 0.71) were constructed for the studied parameters. Multiple response optimization results showed that the most preferred blend should contain 34.66% of grape molasses, 34.11% of sesame paste and 31.23% of honey. Practical Applications: Grape molasses, honey and sesame paste are commonly consumed food products which are rich in energy and many functional components. The people generally consume them in their daily diets especially in their breakfasts. To combine their functionality and sensory properties, an optimization procedure was applied and the mostly desired blend was determined. Blending affected the rheological, textural and bioactive properties of the sample significantly. The results of the study are very important for food industry.
AtıfScopus16WoS15OpenAlex15İncele - MakaleYalnız künye2017Scopus SJRQ2Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels
Yenilmez, A.; Karakan, M.; Çelik, I.
Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens’ structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.
AtıfScopus9WoS5OpenAlex10İncele - MakaleYalnız künye2017Scopus SJRQ2Evaluation of potentially toxic element contents and Pb isotopic compositions in Ankara Stream sediments within an urban catchment in central Turkey
Eker, Çiğdem Saydam; Sipahi, Ferkan; Özkan, Özay; Gümüş, Mustafa Kemal
This study aimed to interpret the spatial distribution, enrichment factor (EF), and geo-accumulation of potentially toxic elements in the bed sediments (ASBS) and Pleistocene-aged overbank sediments (ASOS) of the Ankara Stream in Turkey. The potential toxic pollution of the investigated potentially toxic elements was defined by evaluating the EF, geo-accumulation index (Igeo), and Pb anthropogenic contribution. The distributions of As, Ni, and Co in the analyzed sediments were uniform in the ASBS and ASOS along the length of the stream. The EF and Igeo values indicated that ASBS and ASOS were significantly polluted by As and Ni and moderately polluted by Co, Zn, and Cu. ASBS was locally strongly polluted by Pb and Cd. Pb anthropogenic contribution was estimated at an average of > 100% in the ASBS and ASOS. The potentially toxic element levels and distribution patterns revealed that industrial activities, gasoline combustion, vehicular emission, phosphate fertilizers and natural sources were probable causes of metal pollution in Ankara Stream sediments. These potentially toxic elements were transported by atmospheric conditions and stream water. The potentially toxic elements in Ankara Stream increased with each passing day and were important in evaluating the potential toxicity risks to living organisms. Thus, suitable measures should be taken to ensure appropriate treatment of wastewater before toxic residues are disposed into the nearby stream. Chimney filter, treatment plants, and appropriate technology should be used in the organized industrial zone to prevent atmospheric pollution.
AtıfScopus12WoS10OpenAlex12İncele - MakaleYalnız künye2017Scopus SJRQ2Isolation and Characterization of Thermophilic Bacteria from Geothermal Areas in Turkey and Preliminary Research on Biotechnologically Important Enzyme Production
Baltaci, Mustafa Ozkan; Genc, Berna; Arslan, Sumeyya; Adiguzel, Gulsah; Adiguzel, Ahmet
In this study, the isolation, identification and characterization of the thermophilic bacteria from different hot springs in Turkey were carried out by conventional (morphological, physiological and biochemical tests) and molecular methods (fatty acid methyl esters, GTG5-PCR and 16S rRNA sequencing). These thermophilic bacteria were then tested for their capability to produce enzymes such as lipase, protease, amylase and cellulase. O20 strain is a novel species according to identification studies. All of its isolates were capable of producing industrially valuable enzymes based on screening. In fact, most of them could produce at least two of these enzymes.
AtıfScopus64WoS46OpenAlex71İncele - MakaleAçık Erişim2017Scopus SJRQ3Influence of Duplex Treatment on Structural and Tribological Properties of Commercially Pure Titanium
Çelik, Ilhan
Titanium and its alloys are widely used in many fields, including aerospace and the chemical and biomedical industries. This is due to their mechanical properties, excellent corrosion resistance, and biocompatibility although they do have poor wear resistance. In this study, a duplex layer was successfully formed on the commercially pure titanium surface by duplex treatments (plasma nitriding and physical vapor deposition (PVD)). In the initial treatment, plasma nitriding was performed on the pure titanium samples and in the second treatment, the nitrided samples were coated with CrN by PVD. The friction and wear properties of the duplex-treated samples were investigated for tribological applications. Surface morphology and microstructure of the duplex-treated samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the tribological properties were investigated using pin-on-disc tribometer. A compound layer composed of ϵ-Ti2N and δ-TiN phases and a diffusion layer formed under the compound layer were obtained on the surface of pure titanium after the nitriding treatments. CrN coated on the nitrided surface provided an increase in the surface hardness and in the wear resistance.
AtıfScopus4WoS4İncele - MakaleYalnız künye2017Scopus SJRQ4Molecular docking analysis and determination of minimum inhibition concentration of VIM-38/R228S
Duzgun, Azer Ozad; Saral, Aysegul
Objective: The aim of this study was to determine the effects of residues at 228th positions of VIM-38 on minimum inhibition concentration (MIC) and molecular docking analysis. Materials and methods: blaVIM-38 gene was cloned into expression vector pET100/D-TOPO. Then pET100/D-TOPO-VIM-38 was used to generate the R228S mutation by site-directed mutagenesis. The mutant was transformed into E. coli Dh5α. Changes in the activity of mutation R228S was determined by E-test. Molecular docking analysis of the binding affinity of meropenem and imipenem with VIM-38 and VIM-38 R228S was performed using AutoDock Vina_1_1_2. Results: According to E-test results, pET100/D-TOPO-VIM-38 and pET100/D-TOPO-VIM-38/ R228S have same MIC value for amoxicillin, ticarcillin/clavulanic acid, ampicillin and ticarcillin. It was determined decrease in pET100/D-TOPO-VIM-38/ R228S of MIC for aztreonam, amikacin and cefixine. There are 3-fold deference in MIC between pET100/D-TOPO-VIM-38 and pET100/D-TOPO-VIM-38/ R228S for cefoxitin. pET100/D-TOPO-VIM-38 has 0.5 µg/ml and pET100/D-TOPO-VIM-38/ R228S has 0.125 µg/m for imipenem, we observed 4-fold deference. Also, there is about 170-fold deference between pET100/D-TOPO-VIM-38 (16 µg/ml) and pET100/D-TOPO-VIM-38/ R228S (0.094 µg/ml) for meropenem. VIM-38 and VIM-38 R228S have very close to the negative low free energies of binding of the meropenem and imipenem. Conclusion: These results showed that substitution (R228S) slightly have effect on enzyme activity.
- MakaleAçık Erişim2017Scopus SJRQ1Analysis of transcriptional profiles of Saccharomyces cerevisiae exposed to bisphenol A
Bereketoglu, Ceyhun; Arga, Kazim Yalcin; Eraslan, Serpil; Mertoglu, Bulent
Bisphenol A (BPA), an endocrine disrupting chemical, is used as a monomer in the production of epoxy resins and polycarbonates, and as a plasticizer in polyvinyl chloride. As such, it is produced in large quantities worldwide and continuously leaches into the environment. To capture the genome reprogramming in eukaryotic cells under BPA exposure, here, we used Saccharomyces cerevisiae as model organism and analyzed the genome-wide transcriptional profiles of S. cerevisiae BY4742 in response to BPA, focusing on two exposure scenarios: (1) exposure to a low inhibition concentration (50 mg/L; resulting in <10 % inhibition in cell number) and (2) a high inhibition concentration (300 mg/L; resulting in >70 % inhibition in cell number). Based on the transcriptional profiling analyses, 81 genes were repressed and 104 genes were induced in response to 50 mg/L BPA. Meanwhile, 378 genes were downregulated and 606 genes were significantly upregulated upon exposure to 300 mg/L BPA. While similar processes were affected by exposure to distinct BPA concentrations, including mitochondrial processes, nucleobase-containing small molecule metabolic processes, transcription from the RNA polymerase II promoter, and mitosis and associated processes, the number and magnitude of differentially expressed genes differ between low and high inhibition concentration treatments. For example, exposure to 300 mg/L BPA resulted in severe changes in the expression levels of several genes involved in oxidative phosphorylation, the tricarboxylic acid cycle, ribosomal activity, replication, and chemical responses. Conversely, only slight changes were observed in the expression of genes involved in these processes in cells exposed to 50 mg/L BPA. These results demonstrate that yeast cells respond to BPA in a concentration-dependent manner at the transcriptional level via different genes and provide insight into the molecular mechanisms underlying the modes of action of BPA.
AtıfScopus20WoS18OpenAlex21İncele - MakaleAçık Erişim2017Scopus SJRQ1Rice bran improve probiotic viability in yoghurt and provide added antioxidative benefits
Demirci, Talha; Aktaş, Kübra; Sözeri, Didem; Öztürk, Hale İnci; Akın, Nihat
Experimental yoghurts were made with 13% reconstituted skim milk supplemented with 1, 2, 3% rice bran (RB) and inoculated with probiotic culture of Lactobacillus casei 431. The products were stored at 4 °C for 3 weeks. During this period, the viability of the probiotic L. casei 431 strain and yoghurt starter cultures were evaluated. In addition to this, some physicochemical, antioxidative and sensory properties of yoghurts were also determined. L. casei 431 remained above the 8 log CFU/g throughout the storage period in yoghurts fortified with 2% and 3% RB. Addition of rice bran decreased the syneresis and viscosity values whereas it increased scavenging activities of DPPH radical. However, yoghurts with RB had less sensory scores compared to plain yoghurt.
AtıfScopus115WoS91İncele - MakaleYalnız künye2017Scopus SJRQ2The effect of TiO2 coating on biological NiTi alloys after micro-arc oxidation treatment for corrosion resistance
Sukuroglu, Ebru Emine; Sukuroglu, Suleyman; Akar, Kubra; Totik, Yasar; Efeoglu, Ihsan; Arslan, Ersin
NiTi alloys exhibit good properties, such as shape memory behavior, high corrosion resistant, having the closest elasticity modulus of a human bone and superior biocompatibility properties. However, the surface problems that arise during the use of this alloy limit the usage in the industry and health sector. In recent years, micro-arc oxidation method is used to improve the surface properties and increase the usage of these alloys. In this study, the TiO2 coatings were deposited on the NiTi substrates. The surface topography, morphology, crystallographic structure, and thickness of the coatings were determined using scanning electron microscopy and X-ray diffraction. The corrosion properties were investigated using potentiostat test unit in two different media such as NaCl solution and simulated body fluid. The results show that the coated samples have higher corrosion resistance than uncoated samples in the two different media.
AtıfScopus10WoS11OpenAlex11İncele - MakaleAçık Erişim2017Scopus SJRQ2Sexual health literacy as a predictor of reproductive health and family planning attitudes among university students: a cross-sectional study
Karaahmet, Aysu Yıldız; Bilgiç, Fatma Şule; Karakaş, Sevda
Introduction: This study was conducted to investigate the relationship between sexual health literacy (SHL) and reproductive health and family planning (RHFP) attitudes among university students and to identify the sociodemographic and informational predictors influencing these variables. Methods: A descriptive, cross-sectional design was employed with a sample of 867 university students aged 18-35 in Türkiye between May and September 2024. Data were collected using a Sociodemographic Questionnaire, the Sexual Health Literacy Scale (SHLS), and the Reproductive Health and Family Planning Attitude Scale (RHFPAS). Data analysis included Pearson correlation and multiple linear regression models to determine predictors and relationships. Results: The findings revealed a strong positive correlation between SHL and RHFP attitudes (r = 0.880, P < .05). Multiple linear regression analysis showed that total SHLS scores and students’ conceptual definitions of sexual health were significant predictors of RHFP attitudes. In particular, the knowledge and attitude subscales of the SHLS were identified as key determinants. Furthermore, residence type, sexual activity status, and information sources were found to significantly influence both SHL levels and RHFP attitudes. Discussion: SHL is a critical determinant in shaping the RHFP attitudes of young adults. Higher literacy levels directly correlate with more positive attitudes toward reproductive health services, suggesting that targeted educational interventions are necessary to improve health outcomes in this population.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2017Scopus SJRQ1Environmental impact of Gümüşhane City, Turkey, waste area in terms of heavy metal pollution
Vural, Alaaddin; Gundogdu, Ali; Akpinar, Ibrahim; Baltaci, Cemalettin
The aim of this study is to investigate the occurrence of a heavy metal contamination in a solid waste site of Gümüşhane City, Turkey, to examine the dimensions of the risk of contamination, and to present suggestions for possible solutions. For this purpose, heavy metal contents of soil and leachate samples taken from a Gümüşhane waste site were determined by a new method, microwave plasma-atomic emission spectrometry (MP-AES). When the obtained results are compared with background and control values, it can be seen that the region carries contamination risks, especially in terms of heavy metals such as Zn, Cd, Pb, Cu, Ni, and Co. To examine the environmental effects of the landfill area in more detail, geodeposition index (Igeo), enrichment factor (EF), contamination index (PI), and combined contamination index (IPI) parameters are used. In addition, the samples taken from an area supposed to be free of pollution risk were also analyzed as control samples, and the obtained data were statistically compared with the results of the waste area. It is determined that the results of landfill waste site are dissimilar to those of comparison samples in terms of investigated metals, and that they contained higher values in general.
AtıfScopus19WoS16OpenAlex21İncele - MakaleAçık Erişim2017Scopus SJRQ2Bounds for the radii of univalence of some special functions
Aktaş, Ibrahim; Baricz, Árpád; Yaǧmur, Nihat
Tight lower and upper bounds for the radii of univalence (and starlikeness) of some normalized Bessel, Struve and Lommel functions of the first kind are obtained via Euler-Rayleigh inequalities. It is shown also that the radius of univalence of the Struve functions is greater than the corresponding radius of univalence of Bessel functions. Moreover, by using the idea of Kreyszig and Todd, and Wilf it is proved that the radii of univalence of some normalized Struve and Lommel functions are exactly the radii of starlikeness of the same functions, and they are actually solutions of some functional equations. The Laguerre-Pólya class of entire functions plays an important role in our study.
AtıfScopus35WoS34OpenAlex22İncele - MakaleYalnız künye2017Scopus SJRQ2Series tuned mass dampers in train-induced vibration control of railway bridges
Kahya, Volkan; Araz, Onur
This paper presents the series multiple tuned mass dampers (STMDs) to suppress the resonant vibrations of railway bridges under the passage of high-speed trains (HSTs). A STMD device consisting of two spring-mass-damper units connected each other in series is installed on the bridge. In solution, bridge is modeled as a simply-supported Euler-Bernoulli beam with constant cross-section, and vehicle is simulated as a series of moving forces with constant speed. By the assumed mode method, the governing equations of motion of the beam-TMD device coupled system traversed by a moving train are obtained. The optimum values for the parameters of the STMD device are obtained for the criterion based on the minimization of the maximum dynamic displacement of the beam at its midspan. Single TMD and multiple TMDs in parallel are also considered for demonstration of the STMD device's performance. The results show that STMDs are effective in bridge vibration suppression and robust to parameters' change in the main system and the absorber itself.
AtıfScopus27WoS24İncele