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A New Concept On Sampling Systems By Air Cannon ApplicationYunel, Ufuk 01 January 2004 (has links) (PDF)
The most important criterion in industrial production processes is to control the required product quality and comply with the standards pre-described for the application during any stage of the process. This control begins from the entry of raw material to the plant and continues with pre-determined points.
Mainly two different types of inspection and analyses are used to examine the material quality and content. These are physical and chemical analysis.In most of the production plants above mentioned analyses are made in related laboratories of the plant. Therefore, it is necessary to have & / #65533 / sample& / #65533 / to be analyzed.
This & / #65533 / sample& / #65533 / should have a real & / #65533 / representative& / #65533 / property, which must carry all of the physical and chemical characteristics of the material at the point where this & / #65533 / sample& / #65533 / is taken.The present methods and systems used to take samples from any required point have some disadvantages and present some problems especially for not being & / #65533 / representative& / #65533 / . These problems are discussed in detail within this thesis study and aimed to reach a new concept and system with:
- Low cost of investment
- Low cost of operation
- Less requirement of maintenance and calibration
- The achievement of & / #65533 / correct& / #65533 / and & / #65533 / representative& / #65533 / sample
As a result of the theoretical studies together with practical application works and experiments, a new concept in sampling, namely & / #65533 / Sampling System with Air Cannons& / #65533 / was introduced. The new system of sampling was tested to give better performance and practical use.
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Modeling A Modern Marble Processing Plant By Using Petri NetKeser, Ozge 01 December 2003 (has links) (PDF)
ABSTRACT
MODELING A MODERN MARBLE PROCESSING PLANT BY USING
PETRI NET
Keser, Ö / zge
M. Sc., Department of Mining Engineering
Supervisor: Prof Dr. NeS&rsquo / e Ç / elebi
Co-Supervisor: Prof Dr. Tevfik Gü / yagü / ler
December 2003, 110 pages
All developing countries need sufficient raw material resources to develop
and to guarantee their future. Considering Turkish natural resources,
marble has a great importance because of its demand on the market,
reserve amount and quality. However, some effort is required to improve
the existing marble production and processing efficiency.
Petri nets (PNs) are the information models that control the flow for
concurrent and synchronous systems. In this regard, PN application can
be useful. However, its application is limited to the complex systems and
no application of PN is available in mining sector.
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In this sense, this study aims to examine the applicability of PN to mining.
This study examines the production system in order to optimize the
process in case of two different types of marble product orders. Three
case studies are applied to examine benefits and difficulties in
implementation of PN to a marble processing plant. The study shows that
PN can successfully be used as a tool for the optimization of total
production time, simulation and modeling of the system. It provides to see
the sequence of the processes, their time, remaining time of each
transition and optimum total production times. The difficulties of PN
implementation are found out as the determination of each path in the
reachability graph, matrix representation with large quantity of place, etc.
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Effect Of Discontinuity Roughness And Anisotropy On Shear StrengthDenli, Alper Kaan 01 June 2004 (has links) (PDF)
Discontinuity surfaces generally consist of undulations termed as roughness. It is well known that surface roughness plays an important role on the shear strength and shear behavior of discontinuities. However, the effect of roughness will not be the same when the direction of shearing changes. This effect causes variation of shear strength with shearing direction or in other words anisotropy on shear strength.
In this thesis, an experimental study was performed to investigate the effect of roughness and anisotropy on shear strength. For this purpose, joint samples were prepared using a model material and direct shear tests were conducted at different normal stress levels and shearing directions.
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Comparative Study On Ground Vibrations Prediction By Statistical And Neural Networks Approaches At Tuncbilek Coal Mine, Panel ByhAkeil, Salah 01 June 2004 (has links) (PDF)
In this thesis, ground vibrations induced by bench blasting from the Tunç / bilek Coal Mine, Panel BYH, were measured to find out the site-specific attenuation and to assess the structural damage risk. A statistical approach is applied to the collected data, and from the data analysis an attenuation relationship is established to be used in predicting the peak particle velocity as well as to calculate the maximum allowable charge per delay. The values of frequencies are also analyzed to investigate the damage potential to the structures of Tunç / bilek Township. A new approach to predict the peak particle velocity is also proposed in this research study. A neural network technique from the branch of the artificial intelligence is put forward as an alternative approach to the statistical technique.
Findings of this study indicate, according to USBM (1980) criteria, that there is no damage risk to the structures in Tunç / bilek Township induced by bench blasting performed at Tunç / bilek coal mine, Panel BYH. Therefore, it is concluded that the damage claims put forward by the inhabitants of Tunç / bilek township had no scientific bases. It is also concluded that the empirical statistical technique is not the only acceptable approach that can be taken into account in predicting the peak particle velocity. An alternative and interesting neural network approach can also give a satisfactory accuracy in predicting peak particle velocity when compared to a set of additional recorded data of PPV.
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Electric Potential Response Of The Quartz Bearing Rocks Under Uniaxial LoadingInal, Sinan Hikmet 01 October 2004 (has links) (PDF)
The electric potential changes under uniaxial loading in some minerals and
rocks have long been recognized. To daylight the electrical response of
some minerals and rocks against applied stress, both theoretical studies
and laboratory experiments are conducted. Some theories are also
proposed by different researchers, in order to explain the electric potential
variations. However, the mechanisms leading to electrical potential
generation have not been fully explained yet.
In the explanation of electric potential changes observed in rocks, type of
the observed rock and the rock forming minerals in the rock fabric play an
important role. One theory is based on the fundamentals of piezoelectricity
only. However the relation between the stress state and the electric
generation is not fully understood. This thesis aims to make a further
contribution to the studies on understanding the electric potential change in
rocks, containing quartz, which is a common piezoelectric mineral, under
uniaxial loading conditions.
Three types of rocks, namely quartz-sandstone, granite and granodiorite,
are tested, and the stress and electric potential (EP) variations are recorded
during the uniaxial loading experiments in a continuous manner. The
experiments are conducted at three different loading rates, in order to
investigate the effect of loading rate on the electrification mechanism. Also
step loading experiments are conducted.
Results indicated that, application of uniaxial stress creates a clear change
in the EP responses of three quartz bearing rock types. The possible
relationships between the EP generation and the level of applied stress are
investigated based on the initial and final potential values (EPinitial, EPfinal),
the potential just before the time of failure (EPUCS), the spike-like potential
jump at the time of failure (& / #8710 / V), which are derived from the recorded data of
the experiments.
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Heat Treatment Of Iron Ore Agglomerates With Microwave EnergyCirpar, Cigdem 01 February 2005 (has links) (PDF)
Pelletizing is a size enlargement technique employed to process fine-grained
iron-bearing concentrates and powder ores. Mechanical strength of fired pellets
is important for handling. When the pellets undergo metallurgical processing,
their mechanical strength is a measure of their resistance to degradation by
breakage due to impacts and abrasion to which they are exposed in the upper
part of the blast furnace.
In this study, heat treatment of iron ore agglomerates with microwave energy is
investigated. First drying and then heat hardening tests were performed. Two
main properties of pellets were taken into consideration: percent moisture and
magnetite content for the dried pellets and compressive strength and also
magnetite content for the fired pellets. The tests were conducted with different
particle sized pellets, in different durations. In order to increase the oxidation
rate in heat hardening tests, Na2O2 is also added in different percentages.
The results of the study showed that, magnetite pellets can indeed be dried and
heated with microwave energy. However, the attained compressive strength and
v
the oxidation of the fired pellets were not sufficient as compared to pellets
produced by conventional heating
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Removal Of Heavy Metals In Waste Water By Using Coal Fly AshTuzcu, Emrah Tugcan 01 July 2005 (has links) (PDF)
In this research, it is aimed to remove toxic heavy metals in waste water with the help of fly ash from Ç / ayirhan thermal power plant. The chemical and physical properties (size distribution, specific surface area, porosity, chemical composition, etc.) of fly ash were determined. The experiments were carried out in synthetic waste water containing lead, zinc and copper metals at different concentrations with the addition of fly ash. The effects of metal concentration, agitation time, particle size, ash amount, and pH in the metal removal were examined. With the addition of even very small amount of fly ash, heavy metal removal from waste water was attained at up to 99%. Fly ash particle size has no significant effect on removal of heavy metal ions from solutions. Higher solution pH and longer treatment time were resulted better metal removal. The results also indicated that the main mechanism for metal removal was precipitation due to alkaline characteristics of fly ash and more than 90 % of metals in solutions were removed by precipitation. The pH ranges for maximum metal precipitation were 10-11, 8-10, and 10-11 for copper, zinc, and lead respectively. Very small percentages of adsorbed metal was released during the desorption test.
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Utilization Of Industrial Wastes Of Turkey As Abrasive In Surface Preparation TechnologiesAtaman, Nihat 01 December 2005 (has links) (PDF)
Surface preparation is the key factor in determining the success of a protective coating system and its ultimate objective is to create proper adhesion of a coating over an underlying substrate.
Abrasive blast cleaning involves mechanical cleaning by the continuous impact of abrasive particles at high velocities on to the substrate in a jet stream of compressed air. Industries that use abrasive blasting include the shipbuilding industry, automotive industry, and other industries that involve surface preparation and painting.
Materials from different origins can be used as a blasting media including coal slag, smelter slag, mineral abrasives, metallic abrasives, and synthetic abrasives.
Purpose of this thesis is to investigate the usability of industrial wastes (coal slag, smelter slags, etc.) of Turkey as abrasives in surface preparation technologies.
Four different slag samples of three sources, namely coal furnace slag sample from Ç / ayirhan thermal power plant, ferrochrome slag sample from Eti Krom A.S., granulated blast furnace and converter slag sample from Eregli Iron and Steel Works were studied within the scope of this thesis work. The samples were prepared by crushing and screening. The chemical composition and physical characteristics of the samples were determined. All the samples were tested in industrial scale.
Test results showed that the converter slag meet all the specifications for abrasives and it can be used in blast cleaning operations. However, coal furnace slag, granulated blast furnace slag and ferrochrome slag are not suitable to be used as abrasive in surface preparation technologies.
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Development Of An Elasto-plastic Analytical Model For Design Of Grouted Rock Bolts In Tunnels With Particular Reference To Poor Rock MassesRangsaz Osgoui, Reza 01 January 2007 (has links) (PDF)
The analysis presented in this thesis provides a methodology for grouted bolts design, based on empirical and analytical methods. Hence, the main objectives of this thesis are to offer practical means for better characterisation of poor to very poor rock masses, to better predict support pressure, and to develop an elasto-plastic analytical model for design of grouted bolts in tunnels excavated in such rock masses.
To improve the applicability of the GSI (Geological Strength Index) in poor to very poor rock masses, using Broken Domain Structure (BSTR), Structure Rating (SR), and Intact Core Recovery (ICR), some modifications have been offered, resulting in the Modified-GSI. Applying rock-load height concept and Modified-GSI, an approach to estimate support pressure has been developed. The main advantage of this approach is its applicability in squeezing ground and anisotropic stress conditions. Numerical modelling was carried out in order to adjust the proposed support pressure equation.
Considering convergence reduction approach, an elasto-plastic model based on the latest version of Hoek- Brown failure criterion has been developed for a more effective and practical grouted bolt design. The link between empirical approach and elasto-plastic solution makes it possible to reach more realistic and appropriate bolting pattern design. In this way, the need for the redesign procedure in the convergence reduction approach is eliminated. The results of the proposed elastic-plastic solution have been compared with a numerical model using FLAC2D, and a reasonable agreement was observed. The practical application of the developed methodology is depicted by an analysis of a case study in Turkey.
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Modification Of Magnetic Properties Of Siderite By Thermal TreatmentAlkac, Dilek 01 September 2007 (has links) (PDF)
Obtaining high magnetic susceptibility phases from Hekimhan& / #8211 / Deveci siderite orevia preliminary thermal treatment has been the basic target of the thesis study.Thermal decomposition characteristics of samples, determined bythermogravimetric analysis (TGA), differential thermal analysis (DTA), and
differential scanning calorimetry (DSC), were referenced in advancement of thestudy. Heat treatment experiments, particularly roasting, were carried out byconventional heating and microwave heating. Results showed that roasting of
Hekimhan& / #8211 / Deveci siderite samples could not be achieved by microwave energywhilst conventional heating experiments recorded success. Subsequentlow& / #8211 / intensity magnetic separation of roasted samples gave recovery above 90%,
where low& / #8211 / intensity magnetic separation of run& / #8211 / of& / #8211 / mine sample had failed.
Formation of high magnetic susceptibility phases was verified by magneticsusceptibility balance and x& / #8211 / ray diffraction analysis (XRD), on roasted samples.
Statistical modeling was applied to determine the optimum conditions of roastingin conventional heating system / based on heating temperature, time of heating, particle size as factors.It was concluded that roasting at T= 560 º / C, for t= 45 minutes was adequate toobtain desired results. Particle size was noted to be not much effective on the
process as other factors at the studied size range.
Kinetics (E, n) and reaction mechanism for the thermal decomposition in conventional heating system were evaluated with different solid& / #8211 / state reaction models by interpretation of the model graphs.Three& / #8211 / dimensional diffusion reaction models reported to characterize the thermal decomposition well, with values of activation energy (E), E= 85.53 kJ/mol
(Jander) / E= 85.49 kJ/mol, (Ginstling& / #8211 / Brounshtein).
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