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    Application of Response Surface Methodology and Central Composite Inscribed Design for Modeling and Optimization of Marble Surface Quality
    (Hindawi Ltd, 2016) Cira, Sumeyra Cevheroglu; Dag, Ahmet; Karakus, Askeri
    Factors affecting the final surface quality of polished marble are not yet fully understood. Clarifying these factors for optimization of multivariate polishing process by trial and error method is difficult, time-consuming, and costly task. In this study, the empirical practices were carried out using an experimental design, specifically, a central composite inscribed (CCI) design. The factors considered in CCI design were belt speed, rotational speed, and pressure of the polishing head, and the responses were surface glossiness and roughness. Mathematical models describing responses were produced using experimental datasets, and analysis of variance (ANOVA) was used to assess the fit of the models generated with the experimental data. For process optimization, desirability function analysis (DFA) was used. This study has shown that the CCI could efficiently be applied for the modelling of polishing machine for surface quality of marble strips. Better surface quality generally resulted from lower belt speeds, which increased contact time between the abrasives and strips. Optimized surface quality for marble specimen was established.
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    Determination of basic physical and mechanical properties of basaltic rocks from P-wave velocity
    (Taylor & Francis Ltd, 2013) Karakus, Askeri; Akatay, Mahmut
    Physical and mechanical properties of basaltic rocks used as main building material in historical buildings in Diyarbakir show great diversity depending on the place of origin. Especially, earthquake studies as well as restoration jobs and civil engineers and architects who work on building dynamics need to know basic material properties of basaltic rocks that are the main building material. In this study, the basalt samples obtained from 18 different locations of the Diyarbakir area were tested in order to estimate the main material properties of basalts used in historical buildings without collecting samples from them. Subsequently, statistical relationships between the nondestructive P-wave velocity and other properties of basalts were investigated. Consequently, highly correlated models (R-2=0.717-0.890) were obtained between P-wave velocity and density, porosity, uniaxial compressive strength, Brazilian tensile strength, modulus of elasticity and Poisson's ratio.
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    Effect of basic pumice on morphologic properties of interfacial transition zone in load-bearing lightweight/semi-lightweight concretes
    (Elsevier Sci Ltd, 2011) Ayhan, Mustafa; Gonul, Hatice; Gonul, Ismail Aga; Karakus, Askeri
    The objective of this research is to determine the effect of basic pumice on morphologic properties of interfacial transition zone in load-bearing lightweight/semi-lightweight concretes. In this respect, it has been researched how the chemical and physical structure and the volumetric ratio of basic pumice affected the following three morphologic properties of interfacial transition zone: compactness, width and physical adherence. In accordance with the stated purpose, 15 concrete serials with various properties were produced using basic pumice as aggregate and 670 images were taken from the samples collected from these serials via scanning electron microscope (SEM). Semi-analytical detections were performed based on non-generalizing numeric data obtained in conclusion of the determination of grain limits in these images and comments on visual analysis. In accordance with these detections, it has been concluded that the basic pumice has a high level of potential to contribute to the morphologic properties of interfacial transition zone. (C) 2010 Elsevier Ltd. All rights reserved.
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    Evaluation of the nasal mucociliary transport rate by rhinoscintigraphy in marble workshop workers
    (Sage Publications Inc, 2011) Dostbil, Zeki; Polat, Cahit; Karakus, Askeri; Bakir, Salih; Yuce, Salim
    Marble workers are occupationally exposed to intense environmental marble dust in their workplace. We aimed to investigate the effect of occupational marble dust exposure on nasal mucociliary transport rate (NMTR). Seventeen marble workers and 18 healthy controls were studied. In all subjects, NMTRs were measured by Tc-99m-MAA rhinoscintigraphy. NMTRs of workers and control groups were compared by statistically. Mean NMTR was found as 9 +/- 1.8 mm/min in marble workers whereas mean NMTR of healthy controls was 9.6 +/- 2.2 mm/min. There was no statistically significant difference between NMTRs of workers and control groups (p > 0.05). This study has shown that occupationally exposured marble dusts may not cause functional impairment on NMTR in marble workshop workers.
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    Investigating on possible use of Diyarbakir basalt waste in Stone Mastic Asphalt
    (Elsevier Sci Ltd, 2011) Karakus, Askeri
    Stone Mastic Asphalt (SMA) improved for road construction which has been utilized in Europe and America for 40 years is a rather new process in Turkey. SMA basically consists of 93-94% aggregate and mineral fillers, 6-7% bitumen and additives. Road and construction industry consume stone in large amounts. Stone used are obtained from nearby quarries and carried to the location where they are to be used, destroying the nature and causing large costs. The constantly increasing demand on quarries harms the general structure of the earth thus causing the emergence of large scale environmental problems. The use of basalt waste from stone processing plants as aggregates and mineral filler in SMA might help to meet this increasing demand thus solving environmental problems. In this study, primarily some important material properties of fine and coarse basalt waste, taken from basalt processing plants in Diyarbakir, such as sieve analysis, chemical analysis, specific gravity, water absorption, Los Angeles abrasion loss value, soundness of aggregate by Na2SO4, flakiness index and stripping strength were determined. Then by using this waste material, a SMA was designed according to Turkish Highway Technical Specifications. Marshall stability and flow tests have been carried out on designed SMA specimens. Test results indicate that properties of the basalt waste and the SMA produced were within the specified limits and that these waste materials can be used as aggregates and mineral filler in SMA. (C) 2011 Elsevier Ltd. All rights reserved.
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    Investigation of a methane flare during the excavation of the Silvan irrigation tunnel, Turkey
    (Springer Heidelberg, 2019) Ayhan, Mustafa; Aydin, Deniz; Imamoglu, M. Sefik; Cogalan, Mustafa; Karakus, Askeri
    Mechanized methods are being increasingly used in tunnel excavations to such an extent that to ensure safe construction and the economic viability of projects the need for design-stage geotechnical studies has considerably increased. However, unexpected problems, such as gas inflow, can be experienced during excavation when the geological conditions are insufficiently investigated. In fact, even if construction is taking place in a known oil-natural gas basin or coal-bearing strata, the possibility of methane flare/explosion events can be minimized if a suitable excavation method and equipment are used. However, little published literature is available on this topic, resulting in the potential problem of encounters with sources of methane during construction that have not been considered in the planning of the tunneling operations. We have studied a methane (natural gas) flare incident that occurred in 2015 during the excavation by full-face hard rock tunnel boring machine of the Silvan irrigation tunnel, south-eastern Turkey. During the planning and pre-construction stages no consideration was given to the fact that the tunnel passes through a natural gas basin and, consequently, the selection of excavation method and machine equipment was made without taking into account the high possibility of natural gas being present. During excavation a significant methane gas flare occurred, resulting in 13 workers being injured and abandonment of the project. Subsequent investigations revealed that the proposed route of the tunnel passed through a natural gas basin and that Turkish Petroleum Corporation (TPAO) had carried out natural gas exploration in the area. Here we provide details on the geological background and the flare incident itself and come to the conclusion that the pre-construction ground investigations for this project were grossly inadequate. We also suggest that in order to facilitate economical and safe tunnel construction, consideration should always be given to the possible presence of methane and other gases at the ground investigation stages of tunneling projects and that all previous geological and technical studies related to the study area should be taken into consideration during the pre-construction stage.
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    Investigation of the Effects of Marble Material Properties on the Surface Quality
    (Hindawi Ltd, 2018) Cira, Sumeyra Cevheroglu; Dag, Ahmet; Karakus, Askeri
    This is study aims to investigate the effects of material properties of marble on surface roughness and glossiness. For this purpose, four types of limestones were investigated. Physicomechanical properties of samples were determined through laboratory measurements. Mineralogical and petrographical characterizations were made using thin-section analysis. X-ray fluorescence (XRF) semiquantitative method was used for chemical analysis. Six different grinding-polishing tests for each marble unit were done under fixed operational conditions using the same abrasive series. Relationship between the material properties and the surface quality was investigated. Although the polishing-grinding tests were conducted under the same operational conditions, different levels of roughness and glossiness were observed on different samples. Data obtained from the study proved that the main cause of this difference is textural and chemical composition variations of the marble specimen. Moreover, statistical evaluations showed that porosity, uniaxial compressive strength, and indirect tensile strength have strong effects on the surface roughness and glossiness of the marble specimen. The presence of an inverse relationship between the glossiness and roughness levels was determined as the result of this study as well.