Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Araz, Onur(15)
- Ozturk, Samet(14)
- Ozyurt, E.(9)
- Turk, Veysel(9)
- Reis, Hatice Catal(7)
- Beder, Murat(6)
- Erdogdu, Ferruh(6)
- Peker, Iskender(6)
- Erol, Ismail(5)
- Kaygusuz, Abdullah(5)
- Ozturk, Kasif Furkan(5)
- Wang, Y.C.(5)
- Akpinar, Adem(4)
- Akçay, Serhatcan Berk(4)
- Coskun, Eda(4)
- Kankal, Murat(4)
- Kaya, Selim(4)
- Liu, Shuxiang(4)
- Ozden, Talat(4)
- Seferoğlu, Mehmet Tevfik(4)
- Varol, Temel(4)
- Öztürk, Serkan(4)
- Akinoglu, Bulent G.(3)
- Alemdag, Selcuk(3)
- Arslan, Mehmet(3)
- Cakir, Tufan(3)
- Gurocak, Zulfu(3)
- Gücer, Mehmet Ali(3)
- Günen, Mehmet Akif(3)
- Kaya, Ali(3)
- Mert, Behic(3)
- Mızrak, Sefa(3)
- Saydam Eker, Çiğdem(3)
- Tasci, Caner(3)
- Çelik, Necati(3)
- Ünlü, Ramazan(3)
- Şan, Murat(3)
- Akpinar, A.(2)
- Akpinar, Merve(2)
- Aksa, Hüseyin Can(2)
Yayınlar
- MakaleYalnız künye2017Stereo-based palmprint recognition in various 3D postures
Bingöl, Özkan; Ekinci, Murat
In order to increase performance in palmprint recognition systems, various devices are normally used to restrict the movement of the hand. These can cause problems, especially for those users with physical disabilities. They also cause significant hygiene problems in multi-user systems. Recently, studies on palmprint recognition systems have progressed towards the development of unconstrained, contactless and unrestricted background techniques. The most common problem encountered in these studies is the alignment arising from the free movement of the hand. Despite 3D hand-acquisition devices which offer extra recognition features to overcome this problem, the applicability of these devices is low because of their increased cost. In this study, a stereo camera was proposed. Although due to matching problems, it is difficult to achieve precise, distinct feature extraction in the unrestricted 3D environment used for palmprint recognition, the orientation of the hand in 3D space can be determined by obtaining depth information. In this study, the depth information was extracted by using the binocular stereo approach. First, the orientation of the hand was estimated by fitting a surface model associated with the eigenvectors of the depth information. Pose correction was then accomplished by establishing a relationship between the orientation and the images. The pose correction greatly relieved the perspective distortion that usually occurs within the various poses of the hands. Next, the region of interest was determined by performing segmentation on the corrected images using the Active Appearance Model (AAM). The palmprint features were then extracted via Gabor-based Kernel Fisher Discriminant Analysis. In order to demonstrate the performance of the proposed approach, a new dataset was compiled from stereo images within various scenarios collected from 138 different individuals. As a result of these experimental studies, the EER values, especially on the images captured from different hand orientations in 3D, were reduced from around 14–0.75%. With the help of this suggested approach, the palmprint recognition system was transformed into a more portable form by removing the closed-box mechanisms and equipment restricting movement of the hand. This system can automatically perform pose estimation, hand segmentation and recognition processes without any special intervention.
- MakaleAçık Erişim2017ZnO and ZnO1−x based thin film memristors: The effects of oxygen deficiency and thickness in resistive switching behavior
Gul, Fatih; Efeoglu, Hasan
In this study, direct-current reactive sputtered ZnO and ZnO1−x based thin film (30 nm and 300 nm in thickness) memristor devices were produced and the effects of oxygen vacancies and thickness on the memristive characteristics were investigated. The oxygen deficiency of the ZnO1−x structure was confirmed by SIMS analyses. The memristive characteristics of both the ZnO and ZnO1−x devices were determined by time dependent current–voltage (I-V-t) measurements. The distinctive pinched hysteresis I-V loops of memristors were observed in all the fabricated devices. The typical homogeneous interface and filamentary types of memristive behaviors were compared. In addition, conduction mechanisms, on/off ratios and the compliance current were analyzed. The 30 nm ZnO based devices with native oxygen vacancies showed the best on/off ratio. All of the devices exhibited dominant Schottky emissions and weaker Poole-Frenkel conduction mechanisms. Results suggested that the oxygen deficiency was responsible for the Schottky emission mechanism. Moreover, the compliance currents of the devices were related to the decreasing power consumption as the oxygen vacancies increased.
- MakaleYalnız künye2017An injectable alginate-based hydrogel for microfluidic applications
Akay, Seref; Heils, Rene; Trieu, Hoc Khiem; Smirnova, Irina; Yesil-Celiktas, Ozlem
The objective of this study was to develop an injectable alginate based formulation for immobilizing enzymes into microfluidic systems. The gelation was induced upon lowering the pH by addition of D-glucono-δ-lactone (GDL) and release of Ca+ ions from solid CaCO3. The effects of GDL concentration on enzymatic activity and gelation time were investigated. The results indicated that increasing the GDL concentration increased both surface area and enzymatic activity. Also, chitosan was added to the formulation at different ratios to enhance the stability of enzyme during immobilization. For microfluidic application, 100 μl spiral coil single channel microchip was fabricated and alginate GDL mixture containing β-glucosidase was injected to the microchannel prior to gelation. Enzymatic conversion was performed by pumping substrate (pNPG) through the microchannel. The results indicated that the entire substrate was converted continuously during 24 h without any leakage or deactivation of immobilized enzyme.
- MakaleAçık Erişim2017Reaction of 9-oxabicyclo[4.2.1]non-7-ene-1-ol with tetrazine: An unusually facile intramolecular rearrangement
Kaya, Afşin A.; Salamci, Emine; Menzek, Abdullah; Erdem, Safiye S.; Şahin, Ertan; Ecer, Kadriye
Reaction of (1S*,7R*)-9-oxabicyclo[4.2.1]non-7-en-1-ol (5) with dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate (6) produced (2R*,4R*)-dimethyl 4-(7-oxooxepan-2-yl)-1,4-dihydropyridazine-3,6-dicarboxylate (11) in a one-pot reaction involving cycloaddition at ambient conditions. The structure of the rearrangement product 11 was determined by X-ray crystallographic analysis. Its formation was discussed based on experimental studies and density functional theory calculations. The driving force of this unusually facile reaction was the stability of the caprolactone product 11 and the extremely exorgenic loss of N2. Structural factors facilitating this rearrangement were also explored employing PCM//M06-2X/6-31G(d, p) calculations.
- BildiriAçık Erişim2016A Study on the Performance of GPR for Detection of Different Types of Buried Objects
Toksoz, Derya; Yilmaz, Isik; Seren, Aysel; Mataraci, Isil; Salame, C.; Aillerie, M.; Papageorgas, P.
The objective of this research is to evaluate the applicability of Ground Penetrating Radar (GPR) method to detect burried objects in the shallow depths using 250 MHz and 800 MHz center frequency antennas. For this purpose, different objects were burried in several places of a certain test site. GPR data were collected along six paralel profiles using 250 MHz and 800 MHz antennas which are compatible with RAMAC CU II system. The reflections profile data were processed using the computer program ReflexW. After the processing of data, the reflected /scattered reflections on the processed radargrams were examined and the radargrams were interpreted to determine the depths and positions of the objects from the surface. Also, the data obtained from 250 and 800 MHz antennas were compared and the differences between them in terms of resolution were discussed.
- MakaleYalnız künye2016Determination of the effect of lead mine waste aggregate on some concrete properties and radiation shielding
Çullu, Mustafa; Ertaş, Haydar
The aim of this study is to determine the radiation absorption capacity of concretes produced from lead mine waste which cannot be processed economically as the lead content is low in the mines they are extracted. Lead mine waste (tallow) were exchanged at ratios of 25%, 50% and 75% respectively with barite and limestone aggregates and samples were prepared at C16, C25 and C35 classes. The compressive strength and the unit weight of the prepared samples were determined. The linear absorption coefficients of prepared concrete samples at 662 keV of energy were determined. In addition the relationship between the radiation absorption capacity and the compressive strength–unit weight was investigated. The experiments demonstrated that best absorption was in concrete samples with 100% barite content (100B). On the other hand in the concrete samples prepared from the mixture of limestone and lead mine waste aggregates, it was observed that radiation absorption capacity decreased due to decreasing amount of barite. In concrete samples prepared from the mixture of lead mine waste and limestone aggregates, it was observed that radiation absorption capacity increased due to increasing amount of mine waste aggregates in the concrete. As a result it was observed that lead mine waste aggregates do not absorb as much radiation as barite aggregates depending on the ratio increase of lead mine waste in the aggregate added to the concrete mixture. However the absorbed radiation amount was observed to be higher compared to limestone aggregates.
- MakaleYalnız künye2016Constraints of C-O-S isotope compositions and the origin of the Ünlüpinar volcanic-hosted epithermal Pb-Zn±Au deposit, Gümüşhane, NE Turkey
Akaryali, Enver; Akbulut, Kübra
The Eastern Pontide Orogenic Belt (EPOB) constitutes one of the best examples of the metallogenic provinces in on the Alpine-Himalayan belt. This study focuses on the genesis of the Ünlüpinar Pb-Zn. ±. Au deposit in the southern part of the Eastern Pontide Orogenic Belt. The main lithological units in the study area are the Early Carboniferous Kurtoğlu Metamorphic Complex the Late Carboniferous Köse Granitoid and the Early-Middle Jurassic Şenköy Formation. The studied deposit is hosted by the Şenköy Formation, which consists predominantly of basaltic-andesitic rocks and associated pyroclastic rocks that are calc-alkaline in composition. Silicic, sulfidic, argillic, chloritic, hematitic, carbonate and limonite are the most obvious alteration types observed in the deposit site. Ore microscopy studies exhibit that the mineral paragenesis in deposits includes pyrite, chalcopyrite, sphalerite, galena, gold, quartz and calcite. Electron microprobe analyses conducted on sphalerite indicate that the Zn/Cd ratio varies between 84 and 204, and these ratios point at a hydrothermal deposit related to granitic magmas. Fluid inclusion studies in calcite and quartz show that the homogenization temperature of the studied deposit ranges between 90-160. °C and 120-330. °C respectively. The values of sulfur isotope analysis of pyrite, sphalerite and galena minerals vary between 1.6‰ and 5.7‰, and the results of oxygen and carbon isotope analysis range between 8.4‰ and 18‰ and -5‰ and -3.6‰, respectively. The average formation temperature of the ore was calculated as 264. °C with a sulfur isotope geothermometer. All of the data indicate that the Ünlüpinar deposit is an epithermal vein-type mineralization that was formed depending on the granitic magmatism.
- MakaleYalnız künye2016Structure and surface properties of Al2O3–TiO2 ceramic coated AZ31 magnesium alloy
Çelik, İlhan
Magnesium and its alloys are the engineering materials which have the potential ability to be able to used widely particularly in the automotive, aerospace and in the biomedical sectors, especially thanks to their features such as lightness, specific strength that they have and biocompatibility. However, due to their poor wear resistance and corrosion resistance, the areas of usage are being restricted. This situation prevents Mg alloys to be used without any surface protection despite their good mechanical properties such as high strength/weight ratio. In this study, plasma spraying method is used to improve the poor corrosion resistance of AZ31 Mg alloy. Al2O3–13 wt% TiO2 (AT13) and Al2O3–40 wt% TiO2 (AT40) composite ceramic coatings were coated successfully on the surfaces of AZ31 Mg samples. The wear properties of the AT13 and AT40 coated samples were investigated for tribological applications. Surface morphology and microstructure of the duplex treated samples were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microhardness value of the uncoated AZ31 Mg alloy is 40±3 HV0.1, while the microhardness values of the AT40 and AT13 coatings are enhanced to 800±39 HV0.1 and 1500±35 HV0.1, respectively.
- MakaleYayıncıda açık erişim2016Effects of non-uniform temperature distribution on critical member temperature of steel tubular truss
Ozyurt, E.; Wang, Y.C.
This paper examines the effects of thermal restraint, caused by non-uniform temperature distribution in different members, on the failure temperatures of critical members of steel tubular trusses. Non-uniform temperature distribution develops in trusses exposed to localised fire attack. The truss member nearest to the fire source experiences the highest temperature, with reduced temperatures in the nearby members. The number of the nearby truss members being heated and their temperatures will affect the failure temperature of the critical truss member which has the highest temperature. The aim of this paper is to develop a simplified method to account for the effects of different numbers of members being simultaneously heated to different temperatures on the development of compression force and failure temperature of the critical member. Finite Element (FE) simulations were carried out for Circular Hollow Section (CHS) trusses using the commercial Finite Element software ABAQUS v6.10-1 which has previously been validated by the authors. The simulation trusses were subjected to constant mechanical loads and then increasing temperatures until failure. The elevated temperature stress-strain curves were based on EN-1993-1-2 [1]. Initial geometrical imperfections were included, based on the lowest buckling mode from eigenvalue analysis.The numerical study examined the effects of truss type, critical member slenderness, applied load ratio and axial restraint stiffness ratio on the failure temperatures of the critical truss members. The numerical simulation results were used to check the accuracy of a proposed simplified calculation method, combining linear elastic static truss analysis at ambient temperature and analytical equations to calculated the failure temperatures of thermally restrained truss members based on the regression equations of Wang et al. [2]. The calculation method was shown to be sufficiently accurate for fire resistant design purpose.
- MakaleYalnız künye2016Effect of seasonal changes on the combustion characteristics of impregnated cedar (Cedrus libani A. Rich.) wood
Fidan, M. Said; Yaşar, Ş. Şadiye; Yaşar, Mehmet; Atar, Musa; Alkan, Elif
Wood is an irreplaceable material used as decorative and structural element both indoors and outdoors. When used as a structural material, wood has several superior characteristics in comparison to other structural constituents, although it is adversely affected by fires as well as biotic pests and abiotic effects. In this study, cedar (Cedrus libani A. Rich.) wood samples were impregnated using either Tanalith-E or Wolmanit-CB as detailed in ASTM-D 1413-76 and surface-treated using water-based or synthetic varnish. The impregnated and varnished samples were left outdoors with the aim of investigating the effect of seasonal changes. The samples were later subjected to combustion analysis as detailed in the combustion test standard ASTM-E 160-50. The results of the study indicated that the weight loss was lower during winter (87.82%), for samples that were impregnated using Wolmanit-CB (88.90%) and those that were treated with synthetic varnish (88.45%). On the other hand the O2 and CO2 contents were determined to be the highest in fall during combustion without flame (18.16% and 17.96%, respectively); the CO content was the highest during combustion without flame for the winter samples (28,907 ppm) and the NO content was the highest during combustion without flame for the spring samples (76.15 ppm). In conclusion, the winter samples that were impregnated using Wolmanit-CB and treated with synthetic varnish were determined to be safer to employ in areas with high fire risk.
- MakaleAçık Erişim2015Waste generation and utilisation in micro-sized furniture-manufacturing enterprises in Turkey
Top, Y.
The number of small-scale businesses within most national economies is generally high, especially in developing countries. Often these businesses have a weak economic status and limited environmental awareness. The type and amount of waste produced, and the recycling methods adopted by these businesses during their operation can have negative effects on the environment. This study investigated the types of waste generated and the recycling methods adopted in micro-sized enterprises engaged in the manufacture of furniture. An assessment was also made of whether the characteristics of the enterprise had any effect on the waste recycling methods that were practised. A survey was conducted of 31 enterprises in the furniture industry in Gumushane province, Turkey, which is considered a developing economy. Surveys were undertaken via face-to-face interviews. It was found that medium-density fibreboard (MDF), and to a lesser extent, chipboard, were used in the manufacture of furniture, and two major types of waste in the form of fine dust and small fragments of board are generated during the cutting of these boards. Of the resulting composite board waste, 96.9% was used for heating homes and workplaces, where it was burnt under conditions of incomplete combustion. Enterprises were found to have adopted other methods to utilise their wastes in addition to using them as fuel. Such enterprises include those operating from a basement or first floor of a building in the cities, those continuing production throughout the year, those in need for capital and those enterprises not operating a dust-collection system.
- MakaleYalnız künye2015Accident analysis with the random parameters negative binomial panel count data model
Coruh, Emine; Bilgic, Abdulbaki; Tortum, Ahmet
We analyzed factors affecting the frequency of accident counts in 81 cities over a three-year period (2008-2010) with monthly data using random-parameters negative binomial panel count data models. Among models considered, the random parameters model with the correlated coefficients outperformed the other models and was found to fit the data best with almost a perfect prediction of the conditional mean level. Most of variables used to control for the variation in the frequency of accident counts play crucial role with higher significance levels. Also, marginal effects and elasticity estimates were derived to get more insight into the effects of percent and unit changes in the dependent variable in response to changes in the exogenous variables.
- MakaleYalnız künye2015Building-up a code for the purpose of TRUE coincidence summing correction in gamma-ray spectrometry with EGS4
Celik, Necati; Altin, Duygu; Cevik, Ugur
In the presented study, a code was created for the purpose of true coincidence summing (TCS) correction factors for 134Cs. The created code was implemented in EGS4 Monte Carlo simulation package. TCS factors were determined for nine different energies for different detector-source geometries. The calculated results were successfully validated by an empirical method using a point 134Cs radioactive source and a p-type HPGe detector having 55% relative efficiency. Although the code created gives TCS factors only for 134Cs, the technique presented can be used to obtain the factors for any radionuclide used in gamma-ray spectrometry.
- MakaleYalnız künye2015CFRP composite retrofitting effect on the dynamic characteristics of arch dams
Altunişik, Ahmet Can; Günaydin, Murat; Sevim, Bariş; Bayraktar, Alemdar; Adanur, Süleyman
The purpose of this study is to investigate the effect of retrofitting dynamic characteristics of a damaged laboratory arch dam model, subsequently repaired with high-strength structural mortar and strengthened with composite carbon fiber reinforced polymer. This study constructed in laboratory conditions is a prototype arch dam-reservoir-foundation model. Five test cases of ambient vibration on the arch dam model illustrate the changes in dynamic characteristics: natural frequency, mode shape, and damping ratio, before and after retrofitting. The ambient vibration tests collected data from the dam body during vibrations by natural excitations which provided small impacts and response signals from sensitivity accelerometers placed at crest points. Enhanced Frequency Domain Decomposition Method in the frequency domain extracts the experimental dynamic characteristics. At the end of the study, experimentally identified dynamic characteristics obtained from all test cases have been compared with each other. Apparently, after the retrofitting, the natural frequencies of the dam body increased considerably, demonstrating that the retrofitting, including repairing and strengthening is very effective on the flashback of initial dynamic characteristics.
- MakaleYalnız künye2015Probiotic butter: Stability, free fatty acid composition and some quality parameters during refrigerated storage
Erkaya, Tuba; Ürkek, Bayram; Doğru, Ünsal; Çetin, Bülent; Şengül, Mustafa
This study was carried out to determine whether butter can be a carrier for probiotics by observing the survivability of selected probiotic strains during cold storage. The effects of using probiotic adjunct cultures (Lactobacillus acidophilus ATCC 4356 and Bifidobacterium bifidum ATCC 29521) in butter on microbiological counts, sensory characteristics, chemical characteristics and free fatty acid (FFA) composition during storage for 60 days were investigated. The butter samples produced with B. bifidum ATCC 29521 maintained the probiotic characteristics, in that the level of viable cells of the probiotic was >106 cfu g-1 until 30 days of storage. The highest scores in sensory assessment were obtained on the first day of storage. FFAs, including C2:0, C6:0, C14:0 and C18:1, were affected significantly by storage period and by the adjunct cultures, however conjugated linoleic acid and C18:2 were not affected by storage period and the use of probiotic adjunct culture.
- MakaleYalnız künye2015Determination of the population structure of common bean (Phaseolus vulgaris L.) accessions using lipoxygenase and resistance gene analog markers
Nemli, Seda; Kutlu, Burcu; Tanyolac, Bahattin
The common bean (Phaseolus vulgaris L.) is an important food legume throughout the world. Because of the conservation across different plant species, it is possible to evaluate the degree of genetic diversity in the common bean using gene-based marker techniques. The lipoxygenase (LOX) and resistance gene analog (RGA) genes play an important role in the response to biotic and abiotic stresses. Eighty-six common bean accessions were genotyped using gene-based LOX and RGA markers. The total number of polymorphic bands ranged from 193 for LOX to 17 for RGA markers. We detected considerable diversity with a mean of 8.7 alleles per primer for the LOX analysis. For the RGA markers, the number of alleles per polymorphic locus varied from 1 to 4 with an average allele number of 2.8. The genetic similarity between the accessions based on the LOX and RGA markers ranged from 0.12 to 0.55. Using STRUCTURE, 3 groups were revealed among the accessions. The results of this study should provide valuable information for future studies on the genetic diversity of common bean accessions and for association mapping studies examining the relationships between the genotypic and phenotypic traits related to the stress response.
- MakaleAçık Erişim2015A comparison of support systems obtained from the RMR89 and RMR14 by numerical analyses: Macka Tunnel project, NE Turkey
Kanik, Mustafa; Gurocak, Zulfu; Alemdag, Selcuk
The aim of this study is to highlight the importance of the numerical approach in realistic support design for tunneling. The Macka Tunnel, which is planned to be constructed between the Trabzon-Gumushane highways, located in the Northeastern Turkey, was selected for a field study. The lithology of the study area consists of Late Cretaceous-aged sedimentary rocks, known as the Catak and Esiroglu formations, and the Late Cretaceous-aged Kackar Rhyodacite. In order to determine the geotechnical properties of rock masses and intact rocks, field and laboratory studies were carried out.The rock masses were classified in terms of the Rock Mass Rating (RMR) using the versions of RMR89 and RMR14 and then the preliminary support systems for the tunnel were determined, accordingly. The support systems obtained from the RMR versions were analyzed using the finite element method (FEM). The maximum total displacement and the maximum thickness of plastic zone occurred around the Macka Tunnel after installation the support systems suggested by the RMR89 and RMR14 versions were compared to determine which the RMR version suggests more realistic support system. The results showed that the support systems obtained from the RMR14 version suggests more realistic support element for fair rock masses and great horizontal stress values.
- MakaleAçık Erişim2015Utilization of the limit equilibrium and finite element methods for the stability analysis of the slope debris: An example of the Kalebasi District (NE Turkey)
Alemdag, Selcuk; Kaya, Ayberk; Karadag, Mustafa; Gurocak, Zulfu; Bulut, Fikri
The stability of the slope debris in residential area of the Kalebasi District (Ozkurtun-Gumushane) was investigated using the Limit Equilibrium (LE) and Finite Element Shear-Strength Reduction (FE-SSR) methods. Along the survey lines, four trial pits were dug and fourteen boreholes having a total length of 345m were drilled. Also, seismic refraction studies were conducted along the five lines. According to the field studies, thickness of the slope debris covering the 98ha of the study area varies between 1 and 36m. To determine the physical and shear strength properties of the slope debris, undisturbed samples were taken from the trial pits. As a result of the laboratory tests, soil categories of the debris were found to be as Clayey Sand (SC), Silty Sand (SM) and Low Plasticity Clay (CL). The deformation-controlled shear box tests were carried out to determine the shear strength parameters of the slope debris. According to these tests it was found that the peak cohesion and peak friction angle varies between 2.63-16.35kN/m2 and 20-27°, respectively. Stability analyses were performed using the obtained data from field and laboratory investigations in the Slide v5.0 and Phase2 v6.0 software programs and results were compared. In LE stability analyses, the factor of safety (FOS) of survey lines were found to be as 1.44, 1.80, 1.96, and 1.72; however for the FE-SSR method they were determined as 1.39, 1.72, 1.59, and 1.58, respectively.
- MakaleAçık Erişim2015N-Acylsulfonamides strongly inhibit human carbonic anhydrase isoenzymes i and II
Yildirim, Alper; Atmaca, Ufuk; Keskin, Ali; Topal, Meryem; Çelik, Murat; Gülçin, Ilhami; Supuran, Claudiu T.
Sulfonamides represent a significant class of biologically active compounds that inhibit carbonic anhydrase (CA, EC.: 4.2.1.1) isoenzymes involved in different pathological and physiological events. Sulfonamide CA inhibitors are used therapeutically as diuretic, antiglaucoma, antiobesity and anticancer agents. A series of new sulfonamides were synthesized using imides and tosyl chloride as starting materials. These N-acylsulfonamides efficiently inhibited the cytosolic human carbonic anhydrase isoenzymes I, and II (hCA I, and II), with nanomolar range inhibition constants ranging between 36.4 ± 6.0-254.6 ± 18.0 and 58.3 ± 0.6-273.3 ± 2.5 nM, respectively.
- MakaleYalnız künye2015Utilization of granulated marble wastes and waste bricks as mineral admixture in cemented paste backfill of sulphide-rich tailings
Ercikdi, Bayram; Külekci, Gökhan; Yilmaz, Tekin
This study presents the utilisation of granulated marble wastes (MW) as an additive (10-30 wt%) and waste bricks (WB) as replacement and additive (15-45 wt%) to ordinary Portland cement (OPC) for cemented paste backfill (CPB) of sulphide tailings. OPC was used as binder at 7 wt% dosage. Pozzolanic activity tests showed that the fineness of the WB samples, not the chemical composition, is the major factor affecting their pozzolanic activity. Although they do not exhibit any pozzolanic activity, the use of MW samples as an additive to OPC improves acid buffering capacity of CPB samples and enhances their short and long-term mechanical performance. The UCSs of CPB samples increased with increasing additive rates and decreased with increasing replacement ratios. All CPB samples produced the desired strength and durability when MW and WB were used as an additive to OPC. However, a binder dosage of >7 wt% was required to produce the desired 28-day strength of ≥0.7 MPa when the OPC was replaced by 15-45 wt% WB samples. The durability (i.e. no loss of strength) of CPB samples is closely inter-related with the calcination temperatures and glass phase content of WB.