Yazar "Careddu, Nicola" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • [ X ]
    Öğe
    An Investigation of Colour Properties of Orosei Limestones (Italy) by Using Computer Program
    (Trans Tech Publications Ltd, 2013) Akkoyun, Ozgur; Careddu, Nicola; Marras, Graziella
    In this study, a new computer program developed to determine the colour properties of natural stone products is introduced. The program can scan any digitalised picture of natural stone products and produce several statistical results such as mean, variance, minimum and maximum colour values, skewness and kurtosis values of the colour histogram, energy, contrast, entropy and homogeneity values of the data which may be used to classify the typology and/or quality of natural stone products. As a case study, Orosei limestones (Sardegna, Italy) were used. There are several typologies of Orosei limestones such as Nuvolato (Cloudy), Venato chiaro (Light Veined), Venato medio (Medium Veined), Venato scuro (Dark Veined), Perlato chiaro (Light Pearled), Perlato medio (Medium Pearled) and Perlato scuro (Dark Pearled). The remarkable results produced by the program are presented.
  • Küçük Resim
    Öğe
    An investigation on the efficiency of water-jet technology for graffiti cleaning
    (Elsevier Masson SAS, 2016) Careddu, Nicola; Akkoyun, Özgür
    The scope of this study is to investigate the possible usage of water-jet technology for graffiti cleaning and to find out the best operational conditions of water-jet machine as cleaner. For this goal, Carrara marble was selected as a test stone. Three samples were prepared and 12 different areas were determined on them. Then, different operational conditions of water-jet were applied into these twelve pre-painted marble surfaces. These different operational conditions involve different travel speed, water pressure or inter-distance between passes of the machine to figure out the best combination. After that, image analysis methods were used in order to evaluate the conditions and find out the best one. In addition, roughness features of the marble samples were measured, because water-jet application can cause excavation, which may affect on the stone surface. Finally, it is concluded that water-jet machine can be used for graffiti cleaning with specific operational conditions, which are selected by using both image analysis and roughness test results. As a conclusion, it can be said that if the stone is painted heavily, then travel speed of the machine must be reduced. Oppositely, if the stone is slightly painted, the best solution is to increase both the inter-distance between passes and the travel speed of the jet. Economic considerations of water-jet application are also carried out.
  • Küçük Resim
    Öğe
    Mine simulation for educational purposes: A case study
    (Wiley, 2015) Akkoyun, Özgür; Careddu, Nicola; 0000-0001-9103-8300; 0000-0001-8852-8827
    This paper presents a new simulation-based computer program that provides an interactive and visual environment for teaching and learning of mining engineering related subjects. An actual open pit magnesite mine was selected and whole simulation data were obtained from this mine in order to create a simulation application. The program represents this open pit mine in detail using more than hundred variables, 14 windows, and several modules. It is believed that, with its all components, this educational tool can be used for several mining-related subjects such as drilling and blasting, excavation and haulage, size reduction and magnetic separation at universities to provide fundamental information to the students and anyone dealing with mining engineering related subjects. It may also be used for mining related departments such as geology and geophysics for giving brief information about mining. (c) 2014 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:286-293, 2015; View this article online at ; DOI
  • [ X ]
    Öğe
    Technical-economic assessment of stone slabs surface finishing using water jet technology
    (Springer London Ltd, 2014) Careddu, Nicola; Akkoyun, Ozgur; Medda, Pierpaolo; Tilocca, Caterina
    This paper examines, from an economic standpoint, some of the surface finishing results achieved for stone slabs using high pressure water jets. The results of both the management accounting method and a technical and economic cost analysis method are here applied. The latter method is specifically aimed at verifying and fine-tuning the management analysis model based on the technical coefficient matrix. The second method proposed allows one to examine each process in detail and easily determine technical-economic models for planning, processing and management. The type of production cost analysis proposed here is original, rigorous and precise. The fact that it captures all the most significant technical aspects of the process and clarifies their economic implications makes it far more preferable to the traditional final accounts analyses. Moreover, this technical and economic cost analysis method allows one to accurately calculate the unit cost of each product.