The texture evolution in pipeline steel is studied as a function of the thermo-mechanical processing parameters –rolling tem- perature and cooling rate after the finish rolling stage carried out with equal rolling reduction per pass.. The austenite recrystallization and grain growth during thermo-mechanical control processing (TMCP) of a pipeline steel grade are described and analysed in terms of precipi- tation state progress. Two stage controlled rolling (roughing and finishing) was carried out on a laboratory rolling mill for a set of complet- ed and interrupted schedules. Subsequent to rolling, two different cooling routes were used water quenching and accelerated water cooling (ACC) together with coiling simulation. From the combination of transmission electron microscopy (TEM) observations, detailed texture analysis and inductively coupled plasma-mass spectroscopy (ICPMS) precipitates quantification, consistent correlations between precipita- tion state and microstructure at every stage of TMCP can be recognized. The formation of specific transformation textures was explained via appropriate texture models that describe both formation of transformation and recrystallization textures in the austenite.
Machines. Technologies. Materials.
Vol. 10 (2016), Issue 5
Table of Contents
In the paper the electrodischarge and electrochemical dressing method of super hard grinding wheels using segmental tool electrode and low concentration of electrolytes has been presented. Also the investigation stand for dressing has been depicted. The experimental results concerned forming of cutting surface of grinding wheels (CSGW) in two different processes: electrodischarge profiling and electrochemical dressing. The obtained results confirmed usefulness of both of these processes in forming macro- and microgeometry of CSGW, reduction of geometrical deviations and form dressing of super hard grinding wheels with metal bond. Potential application of electrochemical and electrodischarge methods using diluted solutions of electrolytes for dressing of grinding wheels has been presented. The hybrid system of electrodischarge and electrochemical grinding wheels dressing has been proposed.
NICKEL FERRITE-ACTIVATED CARBON MATERIALS – PREPARATION AND PHOTOCATALYTIC EFFICIENCY FOR CLEANING OF MALACHITE GREEN AND REACTIVE BLACK 5 DYES UNDER UV-ILLUMINATIONpg(s) 10-13
Nickel ferrites having different stoichiometry supported on activated carbon (Ni0.25Fe2.75O4-AC, Ni0.5Fe2.5O4-AC, NiFe2O4-AC) were prepared by co-precipitation using nitrate precursors and activated carbon from peach stones and calcination procedure in nitrogen atmosphere. The physicochemical properties of these materials were studied by powder X-ray diffraction analysis (PXRD) and Mössbauer spectroscopy. The presence of spinel ferrite and additional hematite phases was established by PXRD. The photocatalytic properties of the so synthesized nickel ferrite-AC materials were tested and compared in oxidative degradation of Malachite Green (MG) and Reactive Black 5 (RB5) dyes under UV-light irradiation. The photocatalytic tests show that investigated samples lead to much higher degree of degradation of MG (86%-92%) compared with that of RB5 (17%-35%) due to their structure. The results proved that nickel ferrite-AC materials are more efficient photocatalysts for removal of MG as model contaminant from aqueous solution under UV light than RB5.
This paper presents performances of two different types of PV cells under various temperature clime of Stip, R. Macedonia.
Stip with geographical position 41 .742N, 22.1 94E has 2260 sun hours yearly with average temperature 25 °C during spring.
The types of cells examined in this study are: crystalline silicone (c-Si) and polycrystalline silicon (p-Si). The calculations are made for various operating conditions and a comparation of I-V and P-V characteristics are represented here. Also, the efficiency and fill factor for photovoltaic (PV) cells is calculated based on simulation results.
MHD THREE DIMENSIONAL STAGNATION-POINT FLOW OF A NEWTONIAN FLUID TOWARDS A UNIFORMLY HEATED AND MOVING PERMEABLE VERTICAL PLATEpg(s) 17-20
We investigate the three dimensional stagnation-point flow of an electrically conducting incompressible viscous fluid towards a moving vertical permeable plate in the presence of a transverse uniform magnetic field. The partial differential equations governing flow and heat transfer are reduced to a set of nonlinear ordinary differential equations by using the appropriate transformations. The MATLAB routine BVP4c is successfully applied to solve these nonlinear ordinary differential equations. The results are compared with those known from the literature and an excellent agreement is found. The effects of the suction/injection parameter on the velocity components, wall shear stress, temperature and heat transfer are discussed through the graphs and tables.
THE SOLUTION OF THE SYNTHESIS PROBLEM OF PARTIAL MOTION CONTROL OF A RIGID BODY IN AN INCOMPRESSIBLE VISCOUS FLUIDpg(s) 21-22
The report presents an analytical and numerical analysis of mathematical model of the control synthesis of a solid body moving in an incompressible viscous fluid. It is assumed that the body does not have its own propulsion system, but is equipped with controlled rudders – wings of finite span. It pops up under the influence of the buoyancy force and wings lift. The basic mathematical model was presented by the authors at XII MTM Congress held in September 2015.
High-frequency electric resistance welding is one of the most common process for production of longitudinal seam welded carbon steel pipes suitable for line pipe, casing and tubing. In this pipe production process, the hot rolled strip goes into the forming mill where it is gradually cold formed into a tubular shape in several stages of forming rolls and its edges are continuously joined by a combination of localized electrical resistance heating and forge pressure. High frequency electric resistance welding generally involves high temperature, forge pressure and subsequent cooling, and as the result of this thermal cycle occurs significant microstructural changes. These microstructural changes provides a wealth of information on weld seam quality and edge preparation of hot rolled strips.
In this paper, microstructural changes in the forge weld area during high frequency electric resistance welding (HFERW) of longitudinal seam welded pipes Ø114.3×5.21mm were investigated.
In this paper is studied a vibratory conveyor that is placed on an elastic base. Using the closed contours method it was determined the system that needs to be solved to obtain graphical representation for the generalized coordinates determining the position of the mechanical system elements. The shaking conveyor represents the chase hanged or supported to the fixed section. The chase commits oscillating motions hereupon the cargo which is in the chase, migrates concerning to the chase. The nature of the flow and its parameters are determined by the nature of the oscillating committed by the chase. Justifying the dynamic parameters of the shaking conveyor and a study of the stress-strain state. Installation causes fluctuations fixed tray. Uniformly distributed load on the tray acts in each element of the mechanism. On the basis of the program APM structure 3D investigated the stress-strain state and determined movement of each link mechanism with results and calculations.
The aim of this study was to determine some of the physical and mechanical properties of Turkish hazelnut (CoryluscolurnaL.) wood.Hazelnut is an endemic species in Turkey and the trees used for the study were taken from the Pınarbaşı District of KastamonuProvince. As a resultof experiments carried out to evaluate the physical properties, it was found that the values of dry and air dry density were 0.636 gr/cm3 and 0.672 gr/cm3 , radial, tangential and longitudinal swelling values were 4.60%, 7.48% and 0.41%, radial, tangential and longitudinal shrinkage values were 5.11%, 8.49% and 0.59%, respectively. According to the related standards, the mechanical properties ofbending strength (98.5 N/mm2), modulus of elasticity in bending (8273.4 N/mm2), compressive strength parallel to the grain (50.09 N/mm2 ), dynamic bending strength (impact strength)(0.71 kN/cm), tensile strength perpendicular to the grain (5.09 N/mm2 ), and hardness values of cross, radial and transverse sections (72.55 N/mm2 , 47.32 N/mm2 , 46.13 N/mm2, respectively) were also determined.
MECHANICAL PROPERTIES OF WOOD POLYPROPYLENE COMPOSITES PRODUCED BY USING RESIN IMPREGNATED PAPER WASTEpg(s) 38-40
In this study, it was evaluated some mechanical properties of polypropylene composites reinforced with resin impregnated paper waste (MIPW) obtained from the particleboard and fiberboard factories. To meet this objective, resin impregnated paper waste and pine wood flour were compounded with polypropylene with coupling agent (MAPP) in a twin screw co-rotating extruder and then was manufactured by injection molding process. Injection molded composites were prepared from the wood flour, MIPW powder and polypropylene with maleic anhydride-grafted polypropylene (MAPP) at 10, 20, 30, 40, and 50 wt% contents of the MIPW powder. The tensile and flexural properties of wood polypropylene composites filled with resin impregnated paper waste were decreased. But still, the test results showed that the MIPW can be efficiently used as reinforcing filler for polypropylene composite due to satisfactory mechanical properties of the composites.
This paper presents an access to modeling riveted and welded truss-joints on carrying structure with spatial lattice girder design. The paper illustrates the real model (geometric model) of the most loaded truss-joint on specific carrying structure with its overall complexity. It also illustrates the mathematical model (FE model) of the truss-joint in two designs introducing simplicity, in order to analyze the truss-joint by using a computer and an appropriate software package. FE models (the finite element models) keep up all the characteristics of the geometrical model of the truss-joint, ushering in suitable methodology for this purpose. The need for modeling truss- joints imposes itself as a prior step to further local analysis of stress-deformed conditions of the joint-steel plate under the influence of outside loads. The parallel modeling of the same truss-joint in two constructive designs enables further comparative analysis of stress-deformed shape under same loads and summarize more appropriate constructive design of the truss-joint and emphasizes the need for its optimization.
Test rigs for model hydraulic turbines are used to perform various standardized tests on model turbines by simulating characteristics of the running water, at which the actual turbine will work. Test cell is a frame structure that is placed between the high head and the low head reservoirs of a test rig. It accommodates a generator-bearing assembly and the model turbines to be tested. Since model turbines are custom made systems, the frame structure is required to be designed according to the highest possible loading condition, within the capacity of the test rig, to ensure structural integrity while also considering the ease of assembly. A custom hydrostatic bearing for generator is required to support the potentially harmful axial and radial forces, and bending moments produced by the turbine. In this study, design of a test cell for a hydraulic model turbine test rig is presented.
PRODUCTION OF LAYERED MDF PANEL HAVING FINE FIBERS IN FACE LAYERS AND COARSE FIBERS IN CORE LAYER FOR FURNITURE INDUSTRYpg(s) 46-47
MDF (Medium Density Fiberboard) which is one of the wood-based panels used for industrial applications such as furniture, building materials, and laminate flooring the conventional MDF panels are produced using single layer in the mat forming machine. In this study, it is aimed to produce layered MDF panel for the furniture industry. The surface layers of the MDF consist of fine while the core layers consist of coarse fibers. The MDF panels having different face and core layer ratios could be produced using different defibrator disc gap, which results in different fiber sizes. In the production of layered MDF production, the MDF companies should change their mat forming system, which look like the mat forming of three layers particleboard. The MDF companies having the layered mat forming machine can also use the conventional production which is one layer mat forming production in the MDF. The advantages of three layer MDF are as follows; (1) The amounts of wood and adhesive can be decreased by using the cores fibers used in the core layer of the MDF, (2) The fiber production capacity of the defibrator can be increased using cores fibers, which positively affect the energy saving in the defibrator, (3) The splitting caused by side screw withdrawal resistance can be prevented using core layer consist of coarse fibers.
Inline pipe Francis turbine design is proposed. Spiral case is not used in inline pipe Francis turbines and the flow can enter the stay vanes directly. The flow rate can be distributed uniformly around stay vanes. Another advantage of the new design is that the static pressure drop of the flow is less than that of conventional Francis turbines, which minimize the losses. Working range of the turbine is increased in the new design, as well.
This paper presents an approach for software development that generates control programs in the field of reconfigurable manufacturing systems. The proposed approach proposes the use of developed domain ontologies merged in a meta ontology which is based on the standard for integrated production systems and management IEC / ISO 62264. The article addresses the main graphic elements of the software that are being developed as well the principle of generating control programs.
This paper presents the developed domain ontology of the equipment in manufacturing systems in order to be used in the field of reconfigurable manufacturing systems (RMS). The ontology meets the requirements of the meta-class "Equipment", which is part of the developed meta ontology based on the standard for integrated systems for the production and management IEC / ISO 62264. The article explains various properties and class restrictions of the developed ontology. Web Ontology Language (OWL 2) and Protégé 4.3 as an editor and knowledge acquisition tool are used. Special attention is given to the use of ontology reasoning to infer additional information from the facts stated explicitly in ontology – an important feature, used to perform classification, sorting and assembly operations and consistency checking.
Electron beam melting and refining (EBMR) is one of the modern and widely used technologies which is employed industrially for melting and metal purification. Experimental investigations, computational modeling and optimization approaches are indispensable tools in the study of this ecological technology, for the development and optimization of effective technological schemes and their application to different materials as well as for reducing the price of the pure metals produced. On the basis of experimental and theoretical studies performed, data and results of practical importance for various applications of EBMR are obtained and summarized (for Cu, Ta, Hf, Ti, Au, etc.). The obtained results allow us to formulate requirements on the process parameters and are important and useful in view of studying, controlling and optimizing the quality and purity of the new materials obtained by recycling of metal scrap by EBM.