Machines. Technologies. Materials.
Vol. 8 (2014), Issue 12

Table of Contents

  • SURFACE MORPHOLOGY OF PURE TITANIUM AFTER ANODIZATION

    pg(s) 3-7

    Present paper deals with the investigation of the surface morphology of pure titanium after anodization. Round samples of CP Ti were anodized at different voltages (16V, 20V, 25V, 30V and 40V) in an electrolyte containing 0.5 wt.% HF. The process duration varied from 30min to 7 hours. The samples’ surface was observed and EDX analysis was made by SEM. Surface morphology of CP Ti after anodization is defined by the surface roughness before anodization, electrolyte type and process parameters – voltage and duration. It was established that the surface of pure titanium after 3h-7h anodization at all voltages characterizes with large number of craters increasing the surface micro-roughness. At short-term processes only pores with about 2µm diameter were observed. Depending on the regimes used different oxide nanostructures were observed. After short-term anodization in lower voltages the titanium surface was covered with nanodots, nanorods and nanoflakes. Increasing the voltage up to 25 V led to originating of nano-tubular structure in some areas and sponge-like nano-structure at 30 V and 40 V. Increasing the process duration caused increase of the proportion of nanotubes and sponge- like structure to that of nanorods.

  • USER EVALUATIONS: APPLYING A COST-BENEFIT APPROACH TO HUMAN COMPUTER INTERACTIONS

    pg(s) 8-11

    This study suggests a framework that analyzes individual preferences towards interactive systems by modeling users’ evaluations of the cognitive costs and the benefits of using the systems. A graphical cost-benefit approach, which was originally applied in the area of system analysis and design to help decision-makers select computer systems for organizations, is applied in the area of human-computer interactions (HCI) to predict users’ preferences of alternative application designs. We tie the HCI design methodology of personas to the cost-benefit model. Currently, we mainly propose the applicability of the original model into the field of HCI, and suggest a series of studies that will show that a user’s preference can be predicted using the model. Initial results from a study on a backpack purchasing website already supports the relevance of the original model in HCI and indeed encourages further research to examine the model’s applicability.

  • PRODUCTION OF ALUMINA NANOPARTICLES (AL2O3) USING PULSED LASER ABLATION TECHNIQUE IN ETHANOL SOLUTION

    pg(s) 12-15

    Pulsed Laser Ablation in Liquid (PLAL) has become an increasingly important technique for metals production and metal oxides nanoparticles (NPs). This technique has its many advantages compared with other conventional techniques (physical and chemical). This work was devoted for production of alumina (Al2O3) nanoparticles via PLAL technique from a solid alumina target immersed in ethanol at different values of laser fluences in order to study the effect of laser fluences on the optical properties and structure of Al2O3 nanoparticles. The controllability of particle size and size distribution is shown in this paper to be dependent upon laser fluences and it proved that the ablation at lower fluence led to the creation of smaller nanoparticles, smaller aggregates of nanoparticles, and a lower concentration of nanoparticles in contrast an increase of fluence leads to the formation of larger nanoparticles and most of these NPs were aggregated. The produces NPs were characterized by mean of many tests such as UV-visible (UV-Vis.), Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM).

  • COMPARISON BETWEEN PROJECT MANAGEMENT AND SOFTWARE PROJECT MANAGEMENT

    pg(s) 16-19

    Software project management encompasses the knowledge, techniques and tools necessary to manage the development of software products. Software project management remains different from project management in other more established fields for a number of reasons. Software is “brain product” only, unconstrained by the laws of physics or by the limits of manufacturing processes. In the report discusses topics that managers need to create a plan for software development using effective estimation of size and to execute the plan with attention to productivity and quality.
    In the report they have understand the concept of project management, software project management

  • THERMOMECHANICAL STRENGTHENING AND STABILITY OF AUSTENITIC Cr18Ni10N STEEL

    pg(s) 20-22

    The hardening and austenite stability as a result of nitrogen alloying steel type of Cr18Ni10 in the temperature range, which is usual for the application of such steels as corrosion-resistant structural heat-resistant and/or cryogenic ones was studied. It is shown that the nitrogen alloying is perspective for strengthening and increasing of stability of austenitic stainless steels. Additional strengthening due to the preliminary cold or warm deformation hardening increases a tendency to the martensite formation under load, which limits the operating temperature of these steels. High-strength non-magnetic nitrogen-alloyed steels on the base of Cr18Ni10 steels containing up to 0.22 % of nitrogen are suitable for cryogenic application of non-deformed articles only. Otherwise, a strain-induced martensite will always form in them at temperatures below -70 °С. High strength, ductility and toughness of these steels can be achieved simultaneously only as a result of the TRIP-effect or fine-grained structure formation.

  • IN-SITU STRESS-STRAIN TESTING OF STEELS IN CO2-CONTAINING SALINE SOLUTIONS

    pg(s) 23-25

    In CCS environment (carbon capture and storage) pipes and in geothermal power plants the materials used in pumps are loaded cyclically and exposed constantly to the highly corrosive hot thermal water. The lifetime reduction of AISI630 (X5CrNiCuNb16-4, 1.4542) is demonstrated in in-situ-laboratory experiments (T=60 °C, geothermal brine: Stuttgart Aquifer flow rate: 9 l/h, CO2). S-N plots, micrographic-, phase-, fractographic- and surface analysis were applied to obtain sustainable information on the corrosion fatigue behavior.

  • ROBUST BI-CRITERIA APPROACH TO OPTIMIZE THE COMPOSITION AND PROPERTIES OF TITANIUM ALLOY

    pg(s) 26-30

    The numerical experiment has proved the ability to improve the quality of titanium alloys. Mathematical models suitable for forecasting and optimization have been derived. The approach of Taguchi applied has lead to a desired result, to separate variables Xi for the examined parameters that do not influence significantly on the final result. With this limit, the numerical optimization for maximum search has been conducted with each chemical composition. That allows improving it.

  • ANALYSIS OF THE APPROACHES FOR IMPROVEMENT OF THE ENERGY EFFICIENCY OF ELECTRIC RESISTANCE FURNACES

    pg(s) 31-34

    Chamber electric resistance furnaces (CRF), used for performing of various heating processes, are powerful consumers of electric power. During their operation, different deviations from the original construction may appear and defects, such as: defects in the insulation and the gaskets, deformations of the body, and others. They result in increased thermal flow, running from the chamber to the ambience, increased thermal losses and, as a whole, increased electric power losses. This problem is of special concern in view of current energy efficiency criteria and its solution is sought in the following directions: analysis of the energy efficiency of the furnaces at the stage of their design; analysis of the reconstruction and repair works due to worn-out equipment, consisting in replacement of thermal insulation in order to decrease the losses.

  • CREATING AND RESEARCHING SUSTAINABLE DESIGN OF CORRUGATED CARDBOARD FURNITURE WITH ADVANCED TECHNOLOGICAL MEANS

    pg(s) 35-36

    Furniture made of corrugated cardboard is environmentally friendly, cheap and allow a construction of complex geometry in design and ergonomics of wide application. They may have functional value, art direction, etc. The application of advanced technological means which support the design process of furniture made of cardboard allows optimization of the complete process of creating a sustainable design.

  • NUMERICAL SIMULATION AND EXPERIMENTAL INVESTIGATION OF EQUAL-CHANNEL ANGULAR PRESSING OF POROUS POWDER BILLETS

    pg(s) 37-40

    The theoretical and experimental study of stress-strain state and density distribution into the billet at equal-channel angular pressing has been conducted. It has shown clearly that deformation zone takes a substantial volume with dramatic non-uniformity of stress- strain state after the first pass of equal-channel angular pressing at the backpressure of 90 MPa. The presence of turbulence zone that ensures structure fragmentation of material has established by microhardness indentation. A possibility of production of high-density billets after the second pass at the backpressure of 150 MPa with high mechanical properties and more uniform stress-strain state, free of loosening and cracks has presented.

  • PULSED DISCHARGE TECHNOLOGIES OF PROCESSING AND OBTAINMENT OF NEW MATERIALS (Review)

    pg(s) 41-44

    Review of pulses discharge technologies (PDT), in which pulses electric discharge in liquid is utilized, is given. PDT of processing and obtainment of new materials allows to impact both changes of geometrical size and the structure of objects in order to give it certain mechanical and physical properties. They are used in oil production, instrumentation, mechanical engineering, metallurgy, chemical industry, mining complex, and other.

  • THE ROLE OF SEVERE PLASTIC DEFORMATION IN THE FORMATION OF HIGH ELECTRICAL PROPERTIES OF ALUMINUM ALLOY

    pg(s) 45-47

    At present time there is considerable interest in extending the application area of low-alloy and rather inexpensive heat- hardenable aluminum Al-Mg-Si alloys in the automotive industry, aviation, construction and electrical engineering. In this regard, the topical problem is to enhance strength and electrical conductivity of such materials, which would subsequently reduce the weight of products made of structural and electrical Al-Mg-Si materials. Severe plastic deformation is one of the promising methods of obtaining a significant increase in properties. In this paper a new SPD method is investigated – Multi-ECAP-Conform, characterized by the fact that per one processing cycle the accumulation of true strain is provided up to е>2.5. In order to study the stress-strain state effect on the mechanical properties of the aluminum Al-Mg-Si alloy, mathematical and physical modeling with the modern software Deform-3D were applied, as long as the well-established techniques of assessment of materials mechanical characteristics after plastic processing. The obtained results demonstrate the adequacy of using mathematical and physical modeling to estimate the stress- strain state by Multi-ECAP-Conform.

  • DISSIMILAR WELDING AUSTENITIC STAINLESS STEEL S316 WITH FERRITIC STRUCTURAL STEEL GRADE 300NZS

    pg(s) 48-51

    In this research work, procedure for certification process of dissimilar welding between austenitic stainless steel S316 with structural steel grade 300NZS according EN 15614 standard was explained. Shielded metal arc welding process (SMAW) was used. Welding was performed in PA position with EIS 309 Mo electrode. Qualification test has to confirm that the preliminary welding procedure fulfil quality requirement, and welded joint will satisfy the exploitation conditions. The following investigations were conducted to welded test plate; Visual testing (VT) has to show existence of surface defects in the welded joints. Next step was radiographic testing (RT) in order to check eventually appearing of volumetric defects inside the weld. Finally the plate was cut for mechanical testing. All conducted tests fulfilled requirements except one probe of bend test. Because of that qualification procedure was not successful, and it was completely repeated after two weeks. The repeated welding procedure specification (WPS) was qualified.

  • COMBINED APPROACH FOR MODELING OF MANUFACTURING EXECUTION SYSTEMS

    pg(s) 52-55

    For successful and efficient development of unified modeling framework and software process model (SPM) for MES a new approach is needed. In this paper a modeling framework and SPM that integrates UML profile for system engineering SysML, ANSI/ISA-S95 standard and MES-ML modeling language for MES modeling and specification is presented. The proposed approach is illustrated with a real industrial Pick and Place Unit. Finally some conclusions are made.