Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Alatas, M.(3)
- Batan, N.(3)
- Erata, H.(3)
- Ezer, T.(3)
- Akpinar, Salih(2)
- Aponte Rojas, A. M.(2)
- Atwood, J. J.(2)
- Bednarek-Ochyra, H.(2)
- Bulut, Volkan Numan(2)
- Cano, M. J.(2)
- Duran, Celal(2)
- Ellis, L. T.(2)
- Erzberger, P.(2)
- Espinoza-Prieto, B.(2)
- Goffinet, B.(2)
- Graulich, A.(2)
- Kucera, J.(2)
- Kuzmina, E. Yu.(2)
- Manju, C. N.(2)
- Mir-Rosselló, P. M.(2)
- Sabovljevic, M. S.(2)
- Saribiyik, O.Y.(2)
- Schaefer-Verwimp, A.(2)
- Serin, S.(2)
- Shakira, C.(2)
- Singh, D.(2)
- Sirka, P.(2)
- Soylak, Mustafa(2)
- Suárez, G. M.(2)
- Sérgio, C.(2)
- Tubanova, D. Ya.(2)
- Abdirasulov, F.(1)
- Afonina, O. M.(1)
- Aguirre, J.(1)
- Akbuga, Kursat(1)
- Akdogan, Murat(1)
- Aker, Mert(1)
- Akpinar, S.(1)
- Alba, W. R. Alvaro(1)
- Algül, Engin(1)
Yayınlar
- MakaleYalnız künye2026An assessment of multi-hazard events in post-earthquake temporary shelters: the case of the February 6, 2023 earthquakes in Türkiye
Deniz Ozturk, Yasemin; Peker, Iskender
The 6 February 2023 earthquakes caused catastrophic losses across 11 provinces of T & uuml;rkiye. To meet urgent shelter needs, extensive tent and container settlements were rapidly established; over time, however, these sites proved highly vulnerable to multi-hazard events. This study investigates the spatial and temporal distribution and impacts of fires, floods, and storms on temporary shelters over a two-year period following the earthquakes. In total, 306 events were identified across eight provinces - 155 fires, 147 floods, and 4 storms - damaging 5,075 containers and 420 tents, and causing 16 deaths and 67 injuries. Seasonal factors played a critical role of these hazards. As the earthquakes occurred during winter, the region's cold, rainy conditions led to frequent flooding and numerous heating-related tent fires, particularly in winter and early spring. March recorded the highest number of events due to intense rainfall, storms, and elevated heating demand. Vulnerable groups - including children, workers, and refugees - were disproportionately affected, with children accounting for six fire-related fatalities. Overall, the results highlight the seasonal nature of multi-hazard events in temporary shelter areas and emphasise the need for climate-sensitive planning, hazard mitigation measures, and improved safety standards in post-disaster temporary settlements.
- MakaleYalnız künye2026Selective extraction of rare earth elements from end-of-life NdFeB magnets via low-temperature NH4Cl-based chlorination roasting and water leaching
Kumas, Cavit; Prasetia, Hendra; Sumardi, Slamet; Astuti, Widi; Mufakhir, Fika Rofiek; Daulay, Amru; Wicaksono, Mahruri Arif
Neodymium-iron-boron (NdFeB) magnets are critical components in the transition to a low-carbon energy economy due to their superior magnetic properties. They have significantly higher rare earth element (REE) content (25-35%) compared to natural resources (0.15-2%), making end-of-life NdFeB magnets a valuable secondary REE source. In this study, the selective recovery of REEs from end-of-life NdFeB magnets was investigated using water leaching following chlorination roasting with NH4Cl. A series of experiments was conducted to evaluate the effect of NH4Cl on the NdFeB magnet ratio, roasting temperatures, and roasting duration. Under optimal conditions (300 degrees C, 3 h, NH4Cl at twice the stoichiometric requirement), the roasted products were subjected to water leaching (500 rpm, 90 degrees C, liquid - solid ratio of 20 mL/g, 1 h). resulting in over 95% REE dissolution. Rare earth oxalates were precipitated from the pregnant leach solution with 90% efficiency using 1.5 times the stoichiometric requirement of oxalic acid. Subsequent calcination at 850 degrees C for 2 h yielded rare earth oxides with 99.8% REE purity. Moreover, the dissolution of iron was effectively suppressed through a simple two-stage Fe(OH)3 precipitation step, providing a more economical and selective recovery route. Les aimants de n & eacute;odyme-fer-bore (NdFeB) sont des composants critiques de la transition vers une & eacute;conomie & eacute;nerg & eacute;tique & agrave; faible carbone gr & acirc;ce & agrave; leurs propri & eacute;t & eacute;s magn & eacute;tiques sup & eacute;rieures. Ils ont une teneur en & eacute;l & eacute;ments de terres rares (ETR) sup & eacute;rieures (25-35%) aux ressources naturelles (0.15-2%), ce qui rend les aimants de NdFeB en fin de vie une source secondaire pr & eacute;cieuse d'ETR. Dans cette & eacute;tude, on a examin & eacute; la r & eacute;cup & eacute;ration s & eacute;lective des ETR des aimants de NdFeB en fin de vie par lixiviation aqueuse apr & egrave;s grillage chlorurant avec du NH4Cl. On a effectu & eacute; une s & eacute;rie d'exp & eacute;riences pour & eacute;valuer l'effet du rapport NH4Cl/aimant de NdFeB, des temp & eacute;ratures et de la dur & eacute;e de grillage. Dans des conditions optimales (300 degrees C, 3 h et une concentration de NH4Cl deux fois sup & eacute;rieure & agrave; la st oe chiom & eacute;trie requise), on a soumis les produits grill & eacute;s & agrave; une lixiviation aqueuse (500 tr/min, 90 degrees C, rapport liquide/solide de 20 mL/g, 1 h) conduisant & agrave; une dissolution de plus de 95% des ETR. On a pr & eacute;cipit & eacute; les oxalates de terres rares & agrave; partir de la solution de lixiviation enrichie avec une efficacit & eacute; de 90% en utilisant 1.5 fois la quantit & eacute; st oe chiom & eacute;trique requise d'acide oxalique. Une calcination ult & eacute;rieure & agrave; 850 degrees C pendant 2 h a produit des oxydes de terres rares d'une puret & eacute; de 99.8%. De plus, la dissolution du fer & eacute;tait efficacement supprim & eacute;e par une simple & eacute;tape de pr & eacute;cipitation de Fe(OH)3 en deux phases, offrant une voie de r & eacute;cup & eacute;ration plus & eacute;conomique et plus s & eacute;lective.
- MakaleYalnız künye2026An integrated process for rare earth elements recovery and silica production from Turkish bauxite-related ores
Uysal, Turan; Erüst, Ceren; Erdemoglu, Murat; Sis, Hikmet
The evaluation of bauxite-associated shales as a secondary source of rare earth elements (REEs) is strategically important for securing a sustainable supply of critical raw materials used in advanced technologies. In this study, shale ore associated with bauxite, unsuitable for aluminium production due to its high silica content, was investigated as a potential resource for valuable REEs. The effect of thermal activation on REE recovery was examined, and the potential use of the leach residue as a silica source was assessed. Based on acid leaching results, the optimum calcination temperature was identified as 700 degrees C. Under these conditions, high REE recoveries were achieved: 92.9% La, 89.9% Ce, 89.0% Pr, 88.7% Nd, and 73.0% Sm. After leaching, the residue was enriched in alumina and silica. To improve silica purity and recover remaining REEs and Al, a second-stage leaching process was applied. This resulted in a byproduct containing 55% SiO2 with a specific surface area of 48 m2 g-1, indicating its potential as a silica source. The results demonstrate that bauxite-associated shale can be sustainably valorised through intensive milling, calcination, and acid leaching, enabling efficient REE recovery and the production of a silica-rich byproduct. L'& eacute;valuation de schistes associ & eacute;s & agrave; la bauxite comme source secondaire d'& eacute;l & eacute;ments de terres rares (ETR) est strat & eacute;giquement importante pour garantir un approvisionnement durable en mati & egrave;res premi & egrave;res critiques utilis & eacute;es dans les technologies avanc & eacute;es. Dans cette & eacute;tude, on a examin & eacute; le minerai de schiste associ & eacute; & agrave; la bauxite, inappropri & eacute; & agrave; la production d'aluminium en raison de sa teneur & eacute;lev & eacute;e en silice, comme ressource potentielle d'ETR pr & eacute;cieux. On a examin & eacute; l'influence de l'activation thermique sur la r & eacute;cup & eacute;ration des ETR et l'on a & eacute;valu & eacute; l'utilisation potentielle du r & eacute;sidu de lixiviation comme source de silice. D'apr & egrave;s les r & eacute;sultats de la lixiviation acide, on a identifi & eacute; la temp & eacute;rature optimale de calcination & agrave; 700 degrees C. Dans ces conditions, on a obtenu des r & eacute;cup & eacute;rations d'ETR & eacute;lev & eacute;es: 92.9% de La, 89.9% de Ce, 89.0% de Pr, 88.7% de Nd et 73.0% de Sm. Apr & egrave;s la lixiviation, le r & eacute;sidu & eacute;tait enrichi en alumine et en silice. Afin d'am & eacute;liorer la puret & eacute; de la silice et de r & eacute;cup & eacute;rer les ETR et l'Al restants, on a appliqu & eacute; une deuxi & egrave;me & eacute;tape de lixiviation. Cela a engendr & eacute; un sous-produit contenant 55% de SiO2 et pr & eacute;sentant une surface sp & eacute;cifique de 48 m2/g, indiquant son potentiel en tant que source de silice. Les r & eacute;sultats d & eacute;montrent que le schiste associ & eacute; & agrave; la bauxite peut & ecirc;tre valoris & eacute; de mani & egrave;re durable par broyage intensif, calcination et lixiviation acide, permettant une r & eacute;cup & eacute;ration efficace des ETR et la production d'un sous-produit riche en silice.
- MakaleYalnız künye2026New national and regional bryophyte records, 86
Wilbraham, J.; Abdirasulov, F.; Aguirre, J.; Alatas, M.; Alba, W. R. Alvaro; Ergenekon, Z. Aslan; Raj, K. Aswathy; Ayhan, E.; Batan, N.; Bednarek-Ochyra, H.
- MakaleYalnız künye2025Pan-immune-inflammation value predicts sustained ventricular arrhythmias in NSTEMI: a novel inflammatory risk marker
Sahin, Yusuf Bozkurt; Tanik, Veysel Ozan; Koçu, Gokturk Kaan; Özkan, Mehmet Taha; Akdogan, Murat; Seçkin, Ozden; Tunca, Cagatay; Sezgin, Ali; Akbuga, Kursat; Özlek, Bulent
BackgroundSystemic inflammation contributes to arrhythmogenesis in acute coronary syndromes, but its role in NSTEMI-related ventricular arrhythmias remains poorly defined. The pan-immune-inflammation value (PIV) is a novel composite biomarker reflecting immune and thrombotic activity derived from routine blood counts. This study aimed to assess the association between PIV and the risk of sustained VT/VF in NSTEMI.MethodsIn this retrospective cohort study, 1,788 NSTEMI patients who underwent percutaneous coronary intervention were analyzed. The primary endpoint was the occurrence of sustained VT or VF during hospitalization. PIV was calculated as (neutrophil x platelet x monocyte)/lymphocyte. Logistic regression, ROC analysis, Kaplan - Meier curves, reclassification indices (NRI, IDI), and restricted cubic spline modeling were used.ResultsVT/VF occurred in 34 patients (1.9%). Those with VT/VF had significantly higher PIV values (median 1132 vs. 329, p < 0.001). In multivariable analysis, PIV remained an independent predictor (OR: 1.356 per 1000 unit increase; 95% CI: 1.028-1.787; p = 0.031). The risk of VT/VF rose progressively across PIV quartiles (Q4 vs. Q1 OR: 4.0, p for trend < 0.001). Adding PIV to conventional predictors improved risk classification (NRI: +0.089; IDI: 0.007). Kaplan - Meier analysis showed significantly reduced arrhythmia-free survival in high-PIV tertiles (log-rank p < 0.001), and cubic spline modeling revealed a non-linear association with increased arrhythmic risk at higher PIV levels.ConclusionsElevated PIV is independently associated with malignant ventricular arrhythmias in NSTEMI. As an accessible biomarker, PIV may aid early arrhythmic risk stratification and guide clinical surveillance strategies.
- MakaleYalnız künye2024New national and regional bryophyte records, 79
Ellis, L. T.; Alatas, M.; Ali, Sk. N.; Alvarez, D. J.; Aponte Rojas, A. M.; Atwood, J. J.; Batan, N.; Bednarek-Ochyra, H.; Cano, M. J.; Cimerman, Z. L.
- MakaleAçık Erişim2024New national and regional bryophyte records, 76
Ellis, L. T.; Afonina, O. M.; Alatas, M.; Alia, H. B. M.; Alvarez, J.; Aponte Rojas, A. M.; Atwood, J. J.; Bacilliere, G.; Batan, N.; Biberdzic, V.
- MakaleYalnız künye2023Predicting hospitalization by TAPSE/SPAP and the role of spironolactone in asymptomatic heart failure patients
Aydinyilmaz, Faruk; Guliyev, Ilkin; Özbeyaz, Nail B.; Algül, Engin; Aker, Mert; Sahan, Haluk F.; Erzurum, Muhammed; Felekoglu, Mehmet A.; Kalkan, Kamuran
Aim: To appraise the prediction of tricuspid annular plane systolic excursion (TAPSE)/systolic pulmonary artery pressure (SPAP) with regard to hospitalization and the effect of spironolactone use. Materials & methods: A total of 245 patients were evaluated for the study. Patients were followed for 1 year and cardiovascular outcomes were determined. Results: It was determined that TAPSE/SPAP was an independent predictor of hospitalization. A 0.1-mmHg decrease in TAPSE/SPAP was associated with a 9% increase in relative risk. No event was observed above the 0.47 level. Negative correlation with TAPSE (uncoupling) began in the spironolactone group when SPAP was >= 43 and in nonusers when SPAP was 38 (Pearson's correlation coefficient: -,731 vs -,383; p < 0.001 vs p = 0.037). Conclusion: TAPSE/SPAP measurement may be useful in predicting 1-year hospitalization in asymptomatic heart failure patients. This ratio was also found to be higher in patients who used spironolactone.
- MakaleYalnız künye2021Investigation of fly ash added light concretes with respect to gamma radiation transmission properties of 133Ba and 137Cs
Külekçi, Gokhan
With the help of the developing concrete technology, light concrete and fly ash may be used in several concrete-related fields. To provide protection from radiation, which is one of the current problems of the world, several researchers have used fly ash, but very few researchers have worked on light concrete. To be protected from the effects of radiation, researchers have examined gamma radiation absorption properties by using heavy concrete and heavy aggregates. In this study, by using Class C fly ash at the doses of 30-50-100% instead of cement, three different light concretes were prepared. Density and compressive strength experiments were conducted on the composite blocks prepared with dimensions of 50*50*50 mm, and linear absorption coefficients (cm(-1)), mass attenuation coefficients (MAC) and Tenth value layer (TVL) radiation interaction parameters were measured. Radiation interaction parameters were obtained using an HP Ge gamma detector. For radiation measurements, four different photon energies as 583 keV (Ba-133), 609 keV (Ba-133), 661 keV (Cs-137) and 911 keV (Ba-133) were used. As a result of the analyses, it was determined that compressive strength decreased as the fly ash content increased, the lowest compressive strength values were obtained in the samples containing 100% fly ash among the prepared composites, and density increased as the fly ash content decreased. It was observed that, in the prepared composites, as the energy levels increased, the linear absorption coefficients also increased, and the samples containing 30% fly ash provided the best TVL value on the energy level of 911 keV. With this study, it was revealed that fly ashes that are used in many fields could be used as a radiation shield. Additionally, with this study, due to not using heavy aggregates and due to the production of light concrete in the production of radiation shields, the cost of shield production will significantly decrease.
- MakaleYalnız künye2021Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study
Aydin, Bahir; Ozgur, Armagan; Ozdemir, Huseyin Baran; Inan, Mehmet Arda; Atalay, Hatice Tuba; Bayrakceken, Kemal; Ozmen, Mehmet Cuneyt; Ucgul, Ahmet Yucel; Gocun, Pinar Uyar
Purpose To evaluate the potential toxicity of operation microscopes with halogen and light emitting diode (LED) light source on the rabbit eyes. Materials and methods Thirty-two eyes of 16 male New Zealand pigmented rabbits were involved in the study. The rabbits were divided into two groups according to the type of light source applied. Only one eye of each rabbit was exposed to illumination light, unexposed fellow eyes served as the control group. Experimental groups included group 1 exposed to halogen light for 2 h and evaluated 1 day and 1 week after the illumination, group 2 exposed to LED light for two hours and evaluated 1 day and 1 week after the illumination. On the first and seventh days after exposing the light, we evaluated the rabbit corneas using in vivo confocal microscopy (IVCM). At the end of the seventh day, the Hematoxylin-eosin staining and TUNEL staining were performed to investigate the presence of apoptosis in the retina and retina pigment epithelium. Results Early IVCM findings revealed corneal epithelial cell ovalization and indistinct intercellular borders in the halogen light group. We also observed more increase in the keratocyte density index (23.7% vs 14.1%, p = 0.001, respectively) and the Bowman reflectivity index (12.4% vs 4.1%, p = 0.001, respectively) at first day of the light exposure in halogen light group compared to LED light group. However, late IVCM indicated that these findings disappeared one week later. No apoptosis was observed in the corneal and retinal layers in early and late examination groups. Conclusion The present experimental study demonstrated that both halogen and LED lights, which were commonly used for microscopic eye surgery, had no sustained adverse effect on the cornea and retina of the rabbits; however, halogen light had a temporary adverse effect on corneal epithelium and stroma, which resolved within 1 week.
- MakaleAçık Erişim2016Acetylcholinesterase and carbonic anhydrase isoenzymes I and II inhibition profiles of taxifolin
Gocer, Hulya; Topal, Fevzi; Topal, Meryem; Küçük, Murat; Teke, Dilek; Gülçin, Ilhami; Alwasel, Saleh H.; Supuran, Claudiu T.
Taxifolin, also known as dihydroquercetin, is a flavonoid commonly found in plants. Carbonic anhydrase (CA, EC 4.2.1.1) plays an important role in many critical physiological events including carbon dioxide (CO2)/bicarbonate (HCO3-) respiration and pH regulation. There are 16 known CA isoforms in humans, of which human hCA isoenzymes I and II (hCA I and II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of taxifolin against the slow cytosolic isoenzyme hCA I, and the ubiquitous and dominant rapid cytosolic isoenzyme hCA II were studied. Taxifolin, as a naturally bioactive flavonoid, has a K-i of 29.2nM against hCA I, and 24.2nM against hCA II. For acetylcholinesterase enzyme (AChE) inhibition, K-i parameter of taxifolin was determined to be 16.7nM. These results clearly show that taxifolin inhibited both CA isoenzymes and AChE at the nM levels.
- MakaleYalnız künye2013Separation and pre-concentration of palladium(II) from environmental and industrial samples by formation of a derivative of 1,2,4-triazole complex on Amberlite XAD-2010 resin
Serencam, Huseyin; Bulut, Volkan Numan; Tufekci, Mehmet; Gundogdu, Ali; Duran, Celal; Hamza, Sibel; Soylak, Mustafa
A simple separation/pre-concentration method was developed for extraction of Pd(II) in various environmental samples, based on its adsorption of 4-phenyl-5-{[(4-phenyl-5-pyridin-4-yl-4H-1,2,4-triazole-3-yl)thio]methyl}-4H-1,2,4-triazole-3-thyol (PPTTMET) complex on Amberlite XAD-2010 resin in a mini column. The ligand has high affinity for Pd(II) among many other metals that are taken into consideration. The flame atomic absorption spectrometry is employed to determine the concentration of Pd(II). The optimum working conditions which were determined are as follows: 0.05 mol L-1 HNO3 as working medium, 1.0 mol L-1 HCI in acetone as elution solvent, 0.75 mg of PPTTMET amount and 750 mL of sample volume. The system was independent from the flow rates between 3.1 and 23.1 mL min-1. The Pd(II) adsorption capacity of Amberlite XAD-2010 resin was found to be 12.8 mg g-1 and the enrichment factor was calculated as 375. The method was successfully applied for the determination of Pd(II) in motorway dust samples, anodic sludge, gold ore, industrial electronic waste materials and various water samples.
- MakaleYalnız künye2013Effects of different curvature patches on the strength of double-strap adhesive joints
Akpinar, Salih
In general, the damage in adhesively bonded joints initiates from and propagates through the ends of the overlap area due to high stress concentration in that area. The reduction of these stress concentrations results in an increase in the strength of the joints. For this reason, the rounding of the overlap region before bonding and then applying compression during the bonding process will exert compressive residual stresses on the adhesive layer in the overlap end regions. It is known that the residual stresses formed in this process increase the failure strength of the joint and hence delay the initiation of the damage. In this study, the effects of overlap length (L = 50,75, and 100 mm), patch thickness (h = 1.6, 3.2, and 5 mm) and patch materials (AA2024 aluminum alloy, AISI 304 steel, AISI 1040 steel) on bond strength were experimentally investigated for adhesively bonded double-strap joint (DSJ) and curvature double-strap joint (CDSJ) subjected totensile loading. The experimental study showed that the overlap length, patch thickness and patch materials have considerable influence on the failure strength and displacement capacity of the joints.
- MakaleYalnız künye2013Increasing single-lap joint strength by adherend curvature-induced residual stresses
Temiz, Ş.; Akpinar, S.; Aydin, M.D.; Sancaktar, E.
Single-lap joint (SLJ) geometry is the most widely used type of adhesive joint geometry. In this joint, peel stresses occur at the overlap ends due to load eccentricity and the presence of shear-free adhesive termination surfaces. These peel stresses, along with the transverse tensile stresses which occur along the overlap longitudinal axes, and adhesive shear stresses, ultimately cause joint failure. Obviously, reductions in these stresses should result in higher joint strength and increased load capacity. To this end, we exploited elastic spring-back capability of (steel) metal adherends by initially forming curved segments of varying arc lengths and radii at overlap ends. These adherends with curved-end sections were then bonded in single-lap configuration, simply by applying sufficient bonding pressure to elastically flatten the curved segments to result in typically flat overlap sections subsequent to adhesive cure and the removal of bonding pressure. Since the elastic adherend overlap ends tend to revert back to their initial curved form, they exert compressive residual stresses on the adhesive layer in the overlap end regions. We determined that the compressive residual stresses induced in this fashion considerably increased the load capacity of SLJs subjected to tension.
- MakaleYalnız künye2013Cadmium and nickel determinations in some food and water samples by the combination of carrier element-free coprecipitation and flame atomic absorption spectrometry
Bahadir, Zekeriyya; Ozdes, Duygu; Bulut, Volkan Numan; Duran, Celal; Elvan, Hamide; Bektas, Hakan; Soylak, Mustafa
A procedure for separation and enrichment of Cd(II) and Ni(II) ions based upon carrier element-free coprecipitation by using an organic coprecipitant, 2-{4-[2-(1H-Indol-3-yl)ethyl]-3-(4-methylbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}-N-(3-fluoro-phenylmethyliden) acetohydrazide, prior to their flame atomic absorption spectrometric detections has been developed. The effects of varied experimental conditions on the performance of the developed method such as pH, sample volume, amount of coprecipitating agent, etc. were evaluated in detail on the recovery of analyte ions, and the influences of some anions and cations were investigated. The limits of detection for Cd(II) and Ni(II) ions based on three times the standard deviation of the blanks (N: 10) were obtained as 0.70 g L-1 and 1.21 g L-1, respectively. The accuracy of the method was tested by analyzing a certified reference material and by spike tests. The method was applied to determine the levels of cadmium and nickel in stream and sea water, rice, red lentil, and wheat samples.
- MakaleYalnız künye2012Effect of protrusion at the ends of bondline in single lap joints under tension and bending
Akpinar, Salih; Temiz, Semsettin; Aydin, Murat Demir; Özel, Adnan
In this work, elasto-plastic stress analysis of single lap joints with and without protrusion in adhesive bondline subjected to tension and bending was carried out using 2D non-linear finite element analysis and confirmed experimentally. AA 2024-T3 aluminum adherends were bonded with SBT 9244 film adhesive. The protrusion was obtained by extending the adhesive film by 2 mm from the overlap length at both overlap ends. Three different adherend thicknesses and overlap lengths for each loading and bondline type were used. The joints with and without protrusion, for comparison, were loaded with the same load for each adherend thickness and overlap length. Finally, it was observed that the protrusion reduces the strength in the joint under tension, while the protrusion increases the strength in the joint under bending.
- MakaleYalnız künye2012Monte Carlo modelling of human body for dose conversion coefficients of 137Cs in soil of the Eastern Black Sea region of Turkey
Çelik, Necati
Absorbed dose conversion coefficients for a human body standing on the soil surface were calculated for 137Cs in the soil of Eastern Black Sea region of Turkey using the Monte Carlo simulation method. The results were given in nGy h -1 per Bq cm -2 as a function of depth. Simple numerical integration of this function multiplied with the known specific activity as a function of depth gives the absorbed dose conversion coefficients for any distribution of 137Cs in soil. Gaussian distribution of 137Cs in the soil was considered for calculations.
- MakaleYalnız künye2012Aflatoxin levels in raw and processed hazelnuts in Turkey
Baltaci, C.; Ilyasoǧlu, H.; Cavrar, S.
Aflatoxin levels in hazelnut samples obtained from exporter companies were monitored over a 3-year period. A total of 3188 samples of raw and processed hazelnuts were analysed using an HPLC method. The total aflatoxin content of the contaminated samples was in the range of 0.02-78.98 μg kg-1 for hazelnut kernels, 0.07-43.59 μg kg-1 for roasted hazelnut kernels, 0.02-39.17 μg kg-1 for roasted sliced hazelnut kernels, and 0.02-11.20 μg kg-1 for hazelnut purees, respectively, showing that the variations of aflatoxin contamination were very high. The results of aflatoxin analysis revealed that the aflatoxin contamination in the hazelnut samples was at a tolerable level. A total of 3147 samples were contaminated with aflatoxins, although below the legal limits. However, the aflatoxin contents of 41 samples exceeded the legal limits. Therefore, aflatoxin contents of hazelnuts should be monitored regularly to minimise the risk of aflatoxin hazard, and pre- and post-harvest strategies should be developed to prevent aflatoxin formation.
- MakaleYalnız künye2011Vibration-based operational modal analysis of the mikron historic arch bridge after restoration
Altunişika, Ahmet Can; Bayraktar, Alemdar; Sevima, Bariş; Birincia, Fatma
This research presents finite element modelling, vibration-based operational modal analysis, and finite element model updating of a restored historic arch bridge. Mikron historic bridge, constructed on Fi{dotless}rti{dotless}na River in Rize, Turkey, is the subject of this case study. The General Directorate for Highways of Turkey repaired the bridge's main structural elements, arches, sidewalls, and filler material in 1998. To construct a 3D finite element model of the bridge, ANSYS finite element software estimated the analytical dynamic characteristics. Induced ambient vibrations such as human walking and wind excited the model bridge to allow measurement of the bridge's responses. Enhanced frequency domain decomposition in frequency domain and stochastic subspace identification in time domain methodologies extracted experimental dynamic characteristics. A comparison of the analytical and experimental results showed significant agreement between mode shapes, but some differences in natural frequencies appeared. Consequently, updating the finite element model of the bridge by changing boundary conditions minimised the differences between analytical and experimental natural frequencies. After the finite element model updating process, the differences between natural frequencies declined from 7% to 2%.
- MakaleAçık Erişim2011Mild conditions for oxidation/epoxidation of styrene
Kazanci, A.; Saribiyik, O.Y.; Serin, S.
In this study, in order to obtain novel support materials for immobilization of transition metals, polymeric Schiff bases were synthesized using a poly-condensation reaction between ortho(o-)phthalaldehyde tere(t-)phthalaldehyde, oxaldehyde and diamines like, e.g., ethylene-p- phenylene- and o-phenylenediamine. Additionally, catalytic activity of polymeric Schiff base metal on oxidation/epoxidation of styrene complexes were investigated. The products have been characterized on the basis of analytical and spectral method, Fourier transform infrared spectroscopy, 1H- and 13C-nuclear magnetic resonance, gel-permeation chromatography, elemental analysis, thermogravimetric analysis, atomic adsorbtion spectrometry, gas chromatography and gas chromatography mass spectrometry.