Showing papers in "Journal of achievements in materials and manufacturing engineering in 2010"

Quality Improvement Methodologies - PDCA Cycle, RADAR Matrix, DMAIC and DFSS

Abstract: Purpose: of this paper is to introduce the reader to the characteristics of PDCA tool and Six Sigma (DMAIC, DFSS) techniques and EFQM Excellence Model (RADAR matrix), which are possible to use for the continuous quality improvement of products, processes and services in organizations. Design/methodology/approach: We compared the main characteristics of the presented methodologies aiming to show the main prerequisites, differences, strengths and limits in their application. Findings: Depending on the purpose every organization will have to find a proper way and a combination of methodologies in its implementation process. The PDCA cycle is a well known fundamental concept of continuous-improvement processes, RADAR matrix provides a structured approach assessing the organizational performance, DMAIC is a systematic, and fact based approach providing framework of results-oriented project management, DFSS is a systematic approach to new products or processes design focusing on prevent activities. Research limitations/implications: This paper provides general information and observations on four presented methodologies. Further research could be done towards more detailed study of characteristics and positive effects of these methodologies. Practical implications: The paper presents condensed presentation of main characteristics, strengths and limitations of presented methodologies. Our findings could be used as solid information for management decisions about the introduction of various quality programmes. Originality/value: We compared four methodologies and showed their main characteristics and differences. We showed that some methodologies are more simple and therefore easily to understand and introduce (e.g. PDCA cycle). On the contrary Six Sigma and EFQM Excellence model are more complex and demanding methodologies and therefore need more time and resources for their proper implementation.

A review on an employee empowerment in TQM practice

Abstract: Purpose: This paper discusses the issues of employee’s empowerment, their training needs, suggestions and other issues related to it. Total quality management (TQM) is a management technique adopted by the most manufacturing organizations. TQM in general is viewed as organization set up which will help to manufacture products at lowest cost by the following various management techniques through continuous improvement. Employee empowerment is providing decision making powers to a team or an individual. Design/methodology/approach: Employee empowerment is providing decision making powers for a team or individual. Findings: Employee empowerment is good for an organization and employee is empowered to make specific decision for the interest of the organization. Empowerment helps to play a wider role in an organization as a process owner. Research limitations/implications: This is a conceptual study, and hence, there is no hypothesis tested as an empirical study. It does provide a good foundation for future research. Originality/value: The paper is a conceptual design and more elaborative requirements can be done. This is an input to create awareness among the organizations.

Development of a new aluminium matrix composite reinforced with iron oxide (Fe3O4)

Abstract: Purpose: of this paper is to develop new aluminium matrix (intermetallic) composites reinforced with iron oxide (Fe3O4) that will be used in aeronautical engineering or in electronic industry. Different parameters such as sintering time and temperature, reinforcement, compact pressure were evaluated. The final purpose of this project is going on to improve conductivity and magnetic permeability of this new composite. Design/methodology/approach: In this paper, a new alternative materials “aluminium–iron oxide (Fe3O4, naturally as the mineral magnetite) powder composite” has been developed by using a microwave (in the laboratory scale) sintering programme with various aspect ratios, that iron oxide (Fe3O4) particle sizes and aluminium powders together were prepared. This paper contains partially preliminary results of our going-on research project. Findings: Green density increased regularly depending on the compact pressure and percentage of the iron oxide (Fe3O4). Micro and macro porosity was not found due to very clean microwave sintering. Density after microwave sintering was higher than that of traditional sintering in an electrical oven. Research limitations/implications: This project is going on and magnetic permeability and conductivity of this composite will be improved. Practical implications: This composite is new and clean and thanks to the new microwave sintering basically will be used in aeronautical engineering. Microwave heating results in lower energy costs and decreased processing times for many industrial processes. Originality/value: Originality of this paper is to use a new reinforcement in the aluminium matrix composite; Fe3O4-iron oxide. A new method - microwave sintering- has been carried out on this composite.

Prevention methods against hydrogen degradation of steel

Abstract: Purpose: of this paper is presentation of mechanisms and forms of hydrogen degradation in steel along with pointing out methods for hydrogen degradation prevention. Design/methodology/approach: Hydrogen degradation of steel is a form of environmentally assisted failure which is caused by the action of hydrogen often in combination with residual or applied stress resulting in reduction of plasticity, load bearing capacity of a component, and cracking. Findings: The sources of hydrogen in steel were presented. Forms of hydrogen presence in metals, mechanisms of hydrogen degradation, and types of hydrogen induced damage were discussed in details. Five specific types of hydrogen induced damage to metals and alloys could be distinguished: hydrogen embrittlement, hydrogen-induced blistering, cracking from precipitation of internal hydrogen, hydrogen attack, cracking from hydride formation. Practical implications: Methods for hydrogen degradation prevention include: selection of suitable material, modifying environment to reduce hydrogen charging, and use of surface coatings and effective inhibitors. Originality/value: Originality the paper outlines the problem of hydrogen degradation of steel and other alloys, delivering knowledge to undertake preventive or remedial actions in order to avoid hydrogen induced degradation.

A study on the CO2 laser welding characteristics of high strength steel up to 1500 MPa for automotive application

Abstract: Purpose: This paper presents the mechanical and metallurgical characteristics of laser weldments for automotive steels with high strength ranging from 370 MPa to 1500 MPa. Design/methodology/approach: Butt joint welding was conducted on high strength steel sheets by using a CO2 laser with 6 kW output power. For sound welds with full penetration, the proper welding conditions were chosen and the cross-sectional bead shape, tensile strength, hardness profile and micro-structure were evaluated for each case. Findings: Laser welding is known to be a low heat input process because of its high heat density and welding speed. But for laser welding of ultra high strength steel with strength over 780 MPa, micro-structural softening was observed in the HAZ (heat affected zone), resulting from dissolved martensite. Practical implications: The tensile strength reduction in laser welding of ultra high strength steed should be considered in the design of car body structures. The HAZ softening that occurs in butt joint welding can reduce the tensile shear strength for overlap joint welds, which are predominantly mostly used in the BIW (body-inwhite) structure. Originality/value: This paper quantitatively demonstrates the occurrence of HAZ softening and a tensile strength reduction in laser welding of automotive steel with 780 MPa strength and more.

Polymer composites filled with powders as polymer graded materials

Abstract: Purpose: The goal of this paper is to present general overview of research results on Polymeric Gradient Materials (PGMs) performed in Division of Metallic and Polymeric Materials Processing of Silesian University of Technology. Achievements in research on production technologies, compositions and properties are presented. Design/methodology/approach: Two basic technologies that were used for preparing polymeric gradient composites filled with powders are presented (centrifugal and gravity casting). Composites based on epoxy resin and filled with iron, ferrite, graphite, coal powders are characterized. Among other, the following properties were tested: surface resistivity, coefficient of friction, magnetic induction, filler particles distribution in polymeric matrix and others. Findings: Casting methods presented in this article can successfully be used to produce polymer composites characterized by gradual distribution of powder content and by this way by gradual distribution of properties. Results show that it is possible not only to achieve but also in some extend to control gradient of filler concentration. Especially in centrifugal casting is possible to influence gradient of filler concentration and in this way gradient of many properties. Research limitations/implications: The main problem in presented researches was to introduce higher quantities of filler. The side effect of high filler content was high viscosity. Filler particles were added to the epoxy matrix in range from 3vol.% to 50vol.% depending on filler properties, method of casting etc. Practical implications: Elaborated PGMs may be applied in many fields such as medicine, electronics, mining industry, machine building industry and many others. Originality/value: New type of polymeric gradient composites were achieved using centrifugal and gravity casting technique. Influence of casting parameters, concentration and type of filler on composites properties was researched.

Synthesis and characterization of carbon nanotubes decorated with platinum nanoparticles

Abstract: Purpose: In presented work results of synthesis of carbon nanotubes decorated with platinum nanoparticles by organic colloidal process as an example of direct formation of nanoparticles onto CNTs are reported. Design/methodology/approach: CNT were grown by chemical vapour deposition (CVD) by the catalytic decomposition of CO. To improve metal deposition onto CNTs the purification procedure with a mixture of concentrated HNO3–H2SO4 and H2O2 reduction reagent was applied. CNT–nanocrystal composite was fabricated by direct deposition of nanoparticles onto the surface of CNTs. Chemical composition and crystallographic structure of the obtained Pt/CNT composites were confirmed by energy dispersive X-ray spectroscopy (EDS) and by X-ray diffraction (XRD) measurements, while transmission (TEM) and scanning electron microscopy (SEM) were used for characterization of the morphology of composite as well as the distribution of nanocrystals on the CNTs surfaces. Findings: High efficiency of proposed method was confirmed as well as possibility of the coating of Pt nanoparticles onto CNTs, without aggregation of these particles. Research limitations/implications: Many others noble metals such as palladium, platinum, gold and iridium can be used for deposition on the CNTs using described procedure. Originality/value: Obtained material can be employed in constructing various electrochemical sensors. As a result of increasing of the surface area of Pt caused by the reduction of the size of used particles, fabricated sensor may be characterized by higher sensitivity.

Creep age forming: a short review of fundaments and applications

Abstract: Purpose: The aim is to review creep age forming theoretical fundaments as well as some of our experimental results. Design/methodology/approach: The approach consists of a brief review from basic theoretical concepts of creep and ageing processesincluding a description of anumeric closed form technique to predicting springback in creep age forming. Finally, a work flow to develop a creep age forming process and its respective experimental implementationare shown. Findings: The analytical model and workflow enabled an excellent result of springback predicted value (less than 1%). Research limitations/implications: The experiments only tested simple parts. An improved model is necessary for more complex parts. Practical implications: This work permits to study the creep age forming viability of a given process planning. Originality/value: This review summarizes the main concepts of the creep age forming process and illustrates them by the application of an analytic and numerical modelling performed as a didactic experiment.

Influence of cold rolling on the corrosion resistance of austenitic steel

Abstract: Purpose: The paper analyzes the effects of plastic deformation in cold working process on the corrosion resistance, micro-hardness and mechanical properties of austenitic stainless steel X5CrNi18-10. Design/methodology/approach: Corrosion resistance of X5CrNi18-10 steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 87 days. The evaluation of the corrosion behaviour of investigated steel in the potentiodynamic method was realized by registering of anodic polarization curves. The VoltaLab® PGP 201 system for electrochemical tests was applied. The tests were carried out at room temperature in electrolyte simulating artificial sea water (3.5% NaCl). Registering of anodic polarization curves was conducted at the potential rate equal to 1 mV/s. As the reference electrode the saturated calomel electrode (SCE) was applied, the auxiliary electrode was platinum electrode. Mechanical properties were evaluated on the basis of the static tensile and Vickers micro-hardness test. The observations of the surface morphology after corrosive tests were carried out using Scanning Electron Microscope SUPRATM25. Findings: According to the results of potentiodynamic analyses it was found that plastic deformation in a cold working of austenitic steel grade X5CrNi18-10 affected to lower its corrosion resistance in 3.5% NaCl solution, what has an essential meaning in industrial applications of this group of materials. Research limitations/implications: The microscope observations of the surface samples subjected to corrosion resistance test in 3.5% NaCl solution permitted to evaluate types and the rate of corrosion damages. Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of a special group of steels. Originality/value: The corrosion behaviour in chloride solution of a Cr-Ni austenitic stainless steel was

Methodology of high-speed steels design using the artificial intelligence tools

Abstract: Purpose: The main goal of the research carried out was developing the design methodology for the new highspeed steels with the required properties, including hardness and fracture toughness, as the main properties guaranteeing the high durability and quality of tools made from them. It was decided that hardness and fracture toughness KIc are the criteria used during the high-speed steels design. Design/methodology/approach: In case of hardness, the statistical and neural network models were developed making computation possible of the high-speed steel hardness based solely on the steel chemical composition and its heat treatment parameters, i.e., austenitizing- and tempering temperatures. In this case results of own work on the effect of alloy elements on the secondary hardness effect were used, as well as data contained in catalogues and pertinent standards regarding the high-speed steels. In the second case - high-speed steels fracture toughness, the neural network model was developed, making it possible to compute the KIc factor based on the steel chemical composition and its heat treatment parameters. The developed material models were used for designing the chemical compositions if the new high-speed steel, demonstrating the desired properties, i.e., hardness and fracture toughness. Methodology was developed to this end, employing the evolutionary algorithms, multicriteria optimisation of the high-speed steels chemical composition. Findings: Results of the research carried out confirmed the assumption that using the data from catalogues and from standards is possible, which - would supplement the set of data indispensable to develop the assumed model - improving in this way its adequacy and versatility. Practical implications: Solutions presented in the work, based on using the adequate material models may feature an interesting alternative in designing of the new materials with the required properties. The practical aspect has to be noted, resulting form the developed models, which may successfully replace the above mentioned technological investigations, consisting in one time selection of the chemical composition and heat treatment parameters and experimental verification of the newly developed materials to check of its properties meet the requirements. Originality/value: The presented approach to new materials design, being the new materials design philosophy, assumes the maximum possible limitation of carrying out the indispensable experiments, to take advantage of the existing experimental knowledge resources in the form of databases and most effective computer science tools, including neural networks and evolutionary algorithms. It should be indicated that the materials science knowledge, pertaining oftentimes to the multi-aspect classic problems and described, or - rather - saved in the existing, broadly speaking, databases, features the invaluable source of information which may be used for discovery of the unknown so far relationships describing the material structure - properties relations.

Microstructure and properties of laser surface alloyed PM austenitic stainless steel

Abstract: Purpose: The purpose of this paper is to analyse the effect of laser surface alloying with chromium on the microstructural changes and properties of vacuum sintered austenitic stainless steel type AISI 316L (EN 1.4404). Design/methodology/approach: Surface modification of AISI 316L sintered austenitic stainless steel was carried out by laser surface alloying with chromium powder using high power diode laser (HPDL). The influence of laser alloying conditions, both laser beam power (between 0.7 and 2.0 kW) and powder feed rate (1.0-4.5 g/min) at constant scanning rate of 0.5m/min on the width of alloyed surface layer, penetration depth, microstructure evaluated by LOM, SEM x-ray analysis, surface roughness and microhardness were presented. Findings: The microstructures of Cr laser alloyed surface consist of different zones, starting from the superficial zone rich in alloying powder particles embedded in the surface; these particles protrude from the surface and thus considerably increase the surface roughness. Next is alloyed zone enriched in alloying element where ferrite and austenite coexists. The following transient zone is located between properly alloyed material and the base metal and can be considered as a very narrow HAZ zone. The optimal microstructure homogeneity of Cr alloyed austenitic stainless steel was obtained for powder feed rate of 2.0 and 4.5 g/min and laser beam power of 1.4 kW and 2 kW. Practical implications: Laser surface alloying can be an efficient method of surface layer modification of sintered stainless steel and by this way the surface chromium enrichment can produce microstructural changes affecting mechanical properties. Originality/value: Application of high power diode laser can guarantee uniform heating of treated surface, thus

Postural analysis in HMI design: an extension of OCRA standard to evaluate discomfort level

Abstract: Purpose: The aim of this work consists in developing a design methodology for preventive ergonomics and comfort analyses of Human-Machine-Interface (HMI). Design/methodology/approach: Our method is based on the simulation of the main posture that a digital human model (a manikin representing, for example, a car’s driver) takes while using a machine (in this work, driving a car), in order to judge human safety and comfort during interaction with dashboard, instruments’ panel, levers and other commands. The ergonomic analyses are made using an appropriately modified OCRA (Occupational Repetitive Actions Index) protocol, in order to evaluate different involvement degrees of upper limb segments in comfort action range. Findings: The three-F principle -Human fit, form and function- is becoming the most addressed guideline for improvement and appeal-increasing of product in the current demanding global marketplace. Our work uses modern technologies and new design methods, developed by our research team, and allows to manage and optimize Human Machine Interface under “comfort” point of view.

Ageing process influence on mechanical properties of polyamide - glass composites applied in dentistry

Abstract: Purpose: The application of polymeric materials for medical purposes is growing very fast. Polymers have found applications in such diverse biomedical fields as tissue engineering, implantation of medical devices and artificial organs, prostheses, ophthalmology, dentistry, bone repair and many other medical fields. The requirements for materials used in the construction of removable dentures are becoming more and more demanding. The introduction of improved flexible materials has been a considerable advance. The aim of this work was to determine how the properties of thermoplastic materials change over time in terms of weight changes and artificial saliva sorption. Purpose of this paper was to evaluate the influence of the ageing process on mechanical properties of polyamide - glass composites applied in dentistry. Design/methodology/approach: Polyamide samples about the diversified content of the glass fibre were produced with method of the injection moulding. Denotation of the absorbency of artificial saliva was performed on standardized samples according to the norm. Samples were dried up to fixed mass, and then they were soaked in artificial saliva. Two temperatures of examination were applied 23°C and 30°C.

Springback prediction in V-die bending: modelling and experimentation

Abstract: Purpose: A theoretical model is developed for the air-bending process and V-die bending experiments are conducted. Based on comparisons between springback ratios predicted using the developed theoretical air bending model and the V-die bending experiments, a semi-empirical formula for predicting springback ratio in V-die bending process is suggested. The validity of this formula is verified using finite element simulations as well as comparisons with the results of two other independent sets of experiments. Design/methodology/approach: A theoretical model for air bending is developed and compared with published models. Experimental work on V-die bending is conducted. The experimental results are used in a correlation analysis to develop a mathematical expression for predicting springback ratio of V-die bending as a correction of the spring back ratio of air bending. These results are verified by comparisons with finite element simulations as well as with other independent sets of experiments.

The influence of the environment on the degradation of polylactides and their composites

Abstract: Purpose: The aim of this paper was to determine the influence of environment on degradation process of polylactide-based materials assigned for the implementation in medical implants and short-life products. The hydrolytic degradation, the biodegradation and the degradation under in vivo conditions were determined for the polylactide (PLA), the lactide and glycolide copolymer (PGLA) and the composites modified by hydroxyapatite particles, carbon fibres and natural fibres (hemp, jute). Design/methodology/approach: The degradation was analyzed on the basis of the changes occurring in the environment (such as those in pH fluids), the changes of the mass and resistance of the examined materials, as well as the structural infrared analyses. Findings: It was stated that the degradation time depends on the type of the environment with which the material is in contact. In the water environment, the degradation is faster than in the presence of a compost, and in the Ringer fluid, its speed is higher than in the artificial serum SBF. The in vitro observations focus mainly on the chemical interaction between the examined materials and the artificial environment. The degradation speed is dependent, among others, on the viscosity of the applied fluids and thus, their ability of penetration in the polymer’s structure and on the interfacial boundaries. In a living organism, the fundamental role is played by such processes as the protein adsorption, the cellular and tissue reactions, the body fluid flows and the charge exchanges, and thus, the degradation process is significantly faster than that under in vitro conditions. Practical implications: Result of this study can be used to elaborate the manufacturing method of implants with controlled resorption time and degradable short life time products like packages. Originality/value: In this paper effect of hydrolytic degradation, biodegradation and in vivo degradation on polymers’ and composites’ behaviour was shown. Result of this study can be used to prognosis of durability of degradable materials.

The idea of material science virtual laboratory

Abstract: Purpose: This article was written to describe the Material Science Virtual Laboratory. Presented laboratory is an open scientific, investigative, simulating and didactic medium helpful in the realisation of the scientific and didactic tasks in the field of material Science. This laboratory is implemented in the Institute of Engineering Materials and Biomaterials of Silesian University of Technology in Gliwice, Poland. Design/methodology/approach: The laboratory is an aggregate of testers and training simulators, placed in the virtual reality and created in various languages and the programming techniques, which represents the properties, functionality and manual principles of real equipment installed and accessible in the real laboratories of scientific universities. Findings: Application of the equipment, that is practically imperishable, cheap in exploitation and easy in the use encourages students and scientific workers to independent audits and experiments in situations, where the possibilities of their execution in the real investigative laboratory will be limited because of the high material costs, difficult access to real equipment or the possible risk of his damage. Practical implications: The use possibilities of the virtual laboratory are practically unrestricted; it can be a base for any studies, course or training programme. Originality/value: The project of the virtual laboratory corresponds with the global tendency for expand the investigative and academic centres about the possibilities of training and experiments performance with use of the virtual reality. This enriches investigation and education programmes of the new abilities reserved so far exclusively for effecting only on real equipment

Investigation of the screen printed contacts of silicon solar cells using Transmission Line Model

Abstract: Purpose: The aim of the paper is to analyze how to improve the quality of the screen printed contacts of silicon solar cells. This means forming front side grid in order to decrease contact resistance. Design/methodology/approach: The topography of screen printed contacts were investigated using ZEISS SUPRA 25 scanning electron microscope (SEM) with an energy dispersive X-ray (EDS) spectrometer for microchemical analysis. Front collection grid was created using two types of Ag pastes.The Transmission Line Model (TLM) patterns were fabricated by screen printing method on p – type Czochralski silicon Cz-Si wafer with n+ emitter without texture and with a titanium oxide (TiOx) layer as an antireflection coating (ARC). Electrical properties of contacts were investigated using TLM. Findings: This work presents a conventional analysis of a screen printing process for contact formation in the crystalline silicon solar cells. The seed layer was created using silver pasts by the screen printed metallization. These contact structures were investigated using SEM to gain a better understanding of the obtained electrical parameters. Research limitations/implications: The contact resistance of the screen-printed metallization depends not only on the kind of applied paste and firing conditions, but is also strongly influenced by the surface morphology of the silicon substrate. Practical implications: Contact formation is an important production step to be optimized in the development of high efficiency solar cells. Originality/value: The effect of co-firing different pasts (especially a past, which was prepared using silver nano-powder) on electrical properties of silicon wafers.

Effect of deep cryogenic treatment on substructure of HS6-5-2 high speed steel

Abstract: Purpose: The purpose of this study was using of transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) in order to reveal the changes in substructure of speed steel made with deep cryogenic treatment (DCT), in comparison with substructure formed by conventional heat treatment for secondary hardness. Design/methodology/approach: The HS6-5-2 high speed steel was heat treated in a conventional mode for secondary hardness or was processed in a mode with use of DCT, with and without next tempering. Transmission electron microscopy and scanning electron microscopy observations were carried out. Studies of thermal stability in range of temperatures from -196 °C to 400 °C were performed using differential scanning calorimetry (DSC). Findings: Observations made with aid of SEM-TEM microscope revealed the presence of high density of globular clusters situated at dislocations, and precipitations of the fine carbide plates, located in twinned crystals of martensite. Thermal analysis (DSC) showed an occurrence of higher exothermic effects in specimens treated with use of DCT, than in specimens heat treated conventionally. In steel samples after quenching and DCT the additional exothermic effect was observed. Electron diffraction in TEM studies of these specimens allowed to observe reflections of which indexing exhibited that the precipitated carbide phase has crystallographic structure of B1 type. Research limitations/implications: Extremely high dispersion of carbide phases and a high state of stress that accompanies the stage of precipitation, make difficult the identification of the lattice structure of precipitations, its crystallographic relationships and the degree of coherence with the matrix. Identification of the type of carbides (ε, η, B1, and others) and their coherence with matrix become time-consuming. This important issue requires detailed studies using high-resolution microscopes. Conditions of the early stage of the precipitation process affect the stability of induced strengthening and service-life of tools. Practical implications: Research of HS6-5-2 high speed steel allowed concluding that DCT, besides refinement of martensite grain size, causes an increase of quantity of sites for nucleation of clusters, in which during tempering the B1 carbides are formed. These fine, coherent with matrix and stable carbides are found to be responsible for enhancement of toughness and wear resistance of HSS tools. Originality/value: The issue of DCT is a niche topic in Poland, there are no detailed studies on the changes taking place during this process.

Compositional, physical and chemical modification of polylactide

Abstract: Purpose: The purpose of this article was to review some of the modification methods applied to improve mechanical, barrier and/or surface properties of polylactide (PLA). Design/methodology/approach: The presented modification methods were classified into three groups due to the dominant role of compositional, physical or chemical factor effecting the most PLA properties. Findings: It was found that incorporation of small amounts of montmorillonite up to 5% leads to formation of a nanocomposite with enhanced tensile strength and improved barrier properties. Corona treatment of pure PLA and PLA contained MMT nanofiller causes a significant decrease in the water contact angle and does not essentially affect the diiodomethane contact angle. This treatment leads to an increase in surface free energy that is much more significant for pure PLA than for PLA containing MMT nanofiller. It was also found that with increasing number up to 1000 of laser pulses of energies 5 mJ/cm 2 an increase in surface free energy was observed, while the next laser pulses caused decrease of this energy. The determination and comparison of the influence of 3 wt.% of trimethylopropane trimethacylate (TMPTA) and 3 wt.% of trially isocyanurate (TAIC) crosslinking agents on the thermomechanical properties of electron beam irradiated PLA was reported.

FEM application for modelling of PVD coatings properties

Abstract: Purpose: The general topic of this paper is problem of determining the internal stresses of composite tool materials with the use of finite element method (FEM). The chemical composition of the investigated materials’ core is corresponding to the M2 high-speed steel and was reinforced with the WC and TiC type hard carbide phases with the growing portions of these phases in the outward direction from the core to the surface. Such composed material was sintered, heat treated and deposited appropriately with (Ti,Al)N or Ti(C,N) coatings. Design/methodology/approach: Modelling of stresses was performed with the help of finite element method in ANSYS environment, and the experimental values of stresses were determined basing on the X-ray diffraction patterns. The computer simulation results were compared with the experimental results. Findings: Computer aided numerical analysis gives the possibility to select the optimal parameters for coatings covering in PVD process determining the stresses in coatings, employing the finite element method using the ANSYS software. Research limitations/implications: It was confirmed that using of finite element method in stresses modelling occurring in advanced composite materials can be a way for reducing the investigation costs. In order to reach this purpose, it was used in the paper a simplified model of composite materials with division on zones with established physical and mechanical properties. Results reached in this way are satisfying and in slight degree differ from results reached by experimental method. Originality/value: Nowadays the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality.

The microstructure and mechanical properties of the alloy CuZn30 after recrystallizion annealing

Abstract: Purpose: The aim of the investigations is to determine the influence of the recrystallization temperature on the microstructure and mechanical properties of the brass CuZn30 subjected to cold deformation in the process of rolling at various degrees of strain. Design/methodology/approach: The brass CuZn30 was recrystallization annealed within the temperature range of 300-650°C after cold rolling with the strain of 15.8-70.2%. The tensile test was carried out by the use of universal testing machine. Metallographic observations were performed on an optical microscope and fractographic tests on a scanning electron microscope. The hardness was also measured. Findings: The analysis of the results of investigations concerning the mechanical properties permitted to determine the effect of the temperature of recrystallization annealing on the strength and plastic properties of the investigated brass, subjected to cold deformation with a varying strain in the course of rolling. The character of fracture after decohesion in the tension test was determined basing on fractographic investigations.

Anaerobic digestion of maize hybrids for methane production

Abstract: Purpose: This research project was aimed at optimising anaerobic digestion of maize and find out which maturity class of corn and which hybrid of a particular maturity class produces the highest rate of biogas and biomethane. Also the chemical composition of gases was studied. Design/methodology/approach: Biogas and biomethane production and composition in mesophilic (35 degrees C) conditions were measured and compared. The corn hybrids of FAO 300 - FAO 600 maturity class were tested. Experiments took place in the lab, for 35 days within four series of experiments with four repetitions according to the method DIN 38 414. Findings: Results show that the highest maturity classes of corn (FAO 500) increases the amount of biogas and biomethane. The greatest gain of biogas, biomethane according to maturity class is found with hybrids of FAO 400 and FAO 500 maturity class. Among the corn hybrids of maturity class FAO 300 - FAO 400, the hybrid PR38F70 gives the greatest production of biogas and biomethane. Among the hybrids of maturity class FAO 400 - FAO 500, the greatest amount of biogas and biomethane was produced by the hybrid PIXXIA (FAO 420). Among the hybrids of maturity class FAO 500 - FAO 600 the hybrid CODISTAR (FAO 500) the highest production of biomethane. Production of biomethane, which has the main role in the production of biogas varied with corn hybrids from 50-60 % of the whole amount of produced gas. Research limitations/implications: Economic efficiency of anaerobic digestion depends on the optimum methane production and optimum anaerobic digestion process. Practical implications: The results reached serve to plan the electricity production in the biogas production plant and to achieve the highest biomethane yield per hectare of maize hybrid. Originality/value: Late ripening varieties (FAO ca. 600) make better use of their potential to produce

Experimental and numerical investigation of expandable tubular structural integrity for well applications

Abstract: Purpose: The ever-increasing energy demand has forced researchers to search for new and cheaper solutions for oil and gas production. The recent development of solid expandable tubulars (SETs) has resulted in design of slim oil and gas wells. The large plastic deformation experienced by the tubular under down-hole environment may result in premature and unexpected failures. The objective of this research is to investigate the structural integrity of SET for well applications to avoid such failures. Design/methodology/approach: In order to achieve the objectives, simulation work was carried out using finite element method and experimental tests were conducted on full size tubular for validation of numerical results. Findings: The required drawing force for expansion under different expansion ratios, surplus deformation, variations in tubular thickness and length were estimated numerically and experimentally. The differences in values using two approaches vary from 5% to 12%. Tubular wall thickness decreases as the mandrel angle, expansion ratio, and friction coefficient increase. Research limitations/implications: The issue of maximum expansion a tubular can be subjected to needs to be further investigated. Furthermore, the pre and post-expansion material properties need immediate attention of researchers to fulfil the dream of low-cost expandable solution. Practical implications: In recent years, solid expandable tubular technology has already made significant inroads in replacing conventional telescopic oil wells. It allows design and realization of slim wells, accessing difficult and ultra-deep reservoirs, well remediation, zonal isolation, drilling of directional and horizontal wells, etc. Originality/value: SET is an emerging technology for oil and gas industry. The current findings are very valuable for researchers and well engineers to design slim wells and enhance the productivity of older wells.

Diamonds in meteorites - Raman mapping and cathodoluminescence studies

Abstract: Purpose: The aim of this paper is to show abundance of diamonds existing in the Universe and diamonds diversity among the diversity of other extraterrestrial carbon phases. The main subject of research shown here are example meteorites consisting diamonds: ureilites DaG 868 and Dho 3013. Results are compared with previous investigations. Diamonds exist in many different meteorites, interplanetary dust particles (IDPs) and in comets dust. Origin of different diamonds is still debated among the scientists, two main possibilities are taken into consideration CVD process or shock metamorphism. Understanding laboratory techniques of manufacturing diamond helps in understanding the processes taking place in the Space. From the other side, the new findings and discoveries give the new insight to material science and laboratory techniques. Design/methodology/approach: The samples were examined with different methods, the most investigations presented here are Raman Mapping and Cathodoluminescence (CL). Findings: Diamonds have been found in different samples with different shock stages. It means that not all diamonds in urelites could have shock origin. Diamonds from examined samples show high diversity, they exist in different sizes, from nanodiamonds to micrometer sizes diamonds and in different polytypes. Shifts of Raman diamond peaks indicates this. Research limitations/implications: Results show the possibilities of creating the new diamond-based materials similar to those found in meteorites. Diamond polytypes are not well characterized yet and could give some surprises for materials science. For future research it would be interesting to apply more methods such as X-ray diffraction or HRTEM. Originality/value: SEM+BSE+EDS+CL results and Raman imaging results of DaG 868 and Dho 1303 ureilites are shown for the first time.

The methodological fundaments of development state analysis of surface engineering technologies

Abstract: Purpose: The goal of this paper is to present the authority methodological fundaments of development state analysis of surface engineering technologies against a background of macroand microenvironment. That analysis is carried out as a part of the project entitled “The foresight of surface properties formation leading technologies of engineering materials and biomaterials”. The research project called FORSURF is co-founded by European Regional Development Fund. Design/methodology/approach: The foresight is the whole activity focused on choosing the best future vision and showing ways of that vision realisation using the right methods. However, the approach called technology foresight is the process concentrating scientists, engineers, industrialists, Government officials and others in order to identify areas of strategic research and the leading technologies, which in long term will contribute to the greatest economic and social benefits and sustain industrial competitiveness. The considered FORSURF project belongs to the set of technology foresights. Findings: The set of the crucial technologies in each considered research scope is an expected result of the carried out development state analysis of surface engineering technology against a background of macroand microenvironment. There are fourteen research scopes in the FORSURF project. Research limitations/implications: The results of the development state analysis of surface engineering technologies are the basis conditioning subject matter of the first research iteration of Delphi method carried out within the framework of the FORSURF project. The main research implication of the whole FORSURF project is an identification of strategic research directions crucial in the next 20 years in the field of surface engineering. Practical implications: The practical implication of the definition of the methodological fundaments of development state analysis of surface engineering technology is to show the way of the crucial technologies selection. The consequence of that is a creation of the basic conditioning subject matter of the first research iteration of Delphi method. Originality/value: That paper is the publication concerning the authority methodological fundaments of development state analysis of surface engineering technology against a background of macroand microenvironment within the framework of the FORSURF project. Particularly, the way of the selection of crucial technologies being the basis conditioning a subject matter of the first research iteration of Delphi method is presented.