In situ characterization of the sintering process is a difficult task, in particular for systems without pronounced dimensional changes. Dilatometry is not too helpful in those cases, and therefore other properties have to be recorded. In the present study, sintering of ferrous powder compacts was studied in situ by measuring the thermal diffusivity a using a laser flash apparatus. This property is a measure to characterise the heat flow through a material; it depends on the contact area between the particles and thus reveals their change during sintering. It is shown that the change of a during sintering of ferrous compacts is much less pronounced than in the case of cemented carbides which is not surprising when regarding the widely differing porosity changes. The results are however in good agreement with expectations when considering some experimental limitations. The trend for the thermal conductivity λ. which can be calculated from a, the specific heat and the density, is in good agreement with that found for the electrical conductivity, both properties being linked through Wiedemann-Franz’ law.
Traditionally, powder metallurgy has been based on two major industrial sectors – ferrous precision parts and hardmetals. Both of them relied heavily on the automotive industry, with focus on internal combustion engines. Today, there is an increasing trend towards alternative drivetrain systems, and powder metallurgy faces the challenge to find new applications to replace those lost with the decrease of classical internal combustion drives. In this presentation it is shown that the main strength of powder metallurgy lies in its enormous flexibility regarding materials, geometries, processing and properties. This enables PM to adapt itself to changing requirements in a changing industrial environment. Examples given are PM parts in alternative drivetrain systems, new alloying concepts and processing routes offering distinct advantages. With hardmetals, innovative microstructures as well as sophisticated coatings offer increased lifetime, applications ranging from metalworking to rockdrilling and concrete cutting. A particularly wide area is found in functional materials which range from components for high power switches to such for fuel cells. Soft and hard magnets are accessible by PM with particularly good properties, PM having in part exclusivity in that respect, such as for NdFeB superhard magnets as well as soft magnetic composites (SMCs). Metal injection moulding (MIM) is gaining further ground, e.g. in the medical area which is a fast-growing field, due to demographic effects. Finally, most additive manufacturing techniques are powder based, and here, the knowledge in powder handling and processing available in the PM community is essential for obtaining stable processes and reliable products. Conclusively it can be stated that PM is on the way to fully exploit its potential far beyond its traditional areas of applications.
Analysis and simulation of the Strapdown Inertial Navigation System (SINS) error genesis revealed that the East Feedback Contour has the greatest influence on the development of an error in this model, and angular velocity sensor Δω𝒚 is the critical element. In order to prevent the development of an error, structural correction in the East Feedback Contour, and elements that are more critical, namely in angular velocity measurement sensors is the best option.
Adam Torok, Tadej Derenda, Marina Zanne and Mate Zoldy
In this article automatization of road transport is investigated. In the first chapter relevant international trends were identified. In this paper the research hypothesis is that in the case of automatized road vehicles there is a significant likelihood of endangering human life. Secondly, the history of road safety is shortly described, especially focusing on vehicle design and sweep of system’s theory. In the third chapter evolution of drivers’ assistance systems were elaborated, emphasizing especially autonomous vehicles. Finally, in conclusion the authors warn that new technological solutions could pose new threats.
Behaviour-Based Safety (BBS) is a popular approach to enhancing occupational safety, with many researchers reporting successes of implementing BBS programs. There are, however, studies that see this approach as illusory, bringing more harm than good. The first goal of this article is to present an overview of literature providing both evidence and elaboration of implementing BBS programs, highlighting both positive and negative views of the approach. The second goal is to discuss the perception of the method, based on a literature review and authors’ own research.
The paper concentrate on the problems of customers satisfaction from services in incubator centres in USA and Poland. The aim of the paper is to analyse the level of satisfaction of Business Incubation Centre on the example of two incubator centres one from USA (Hazelton CAN-Be in Pennsylvania and second in Gliwice Poland). The analysis was conducted in pre-incubation and incubation stage. The analysis was conducted on example of survey analysis in both incubator centres. On the base of achieved results we assessed the priority of customers in each incubator centre.
The article presents the importance of economic and social responsibility of the brewing industry, pointing to the aspect of synergy related to the brewing industry in the processes of economic development (creation of many jobs in the agricultural sector, retail trade and gastronomy), stimulating specific areas of local and regional development. The principles of organization and supervision of food quality and safety in beer brewing as well as the importance of implementing management systems in the activity of brewing industry companies were presented.
Today, with the spread of autonomous functions in vehicles, the role accountability for causing accidents is emphasized. Self-guided functions work in certain traffic situations, but accidents happen, and, therefore, the following article presents an analysis of the issue. Its purpose is to show that vehicles with self-drive functionality do not provide the driver's level of safety that vehicle manufacturers suggest. In this article, four recent events and an analysis whether these accidents could have been avoided a human driver or how they could have happened with appropriate self-drive function. In each of the investigated cases, vehicles equipped with self-drive function are involved. Based on the evaluation and assessment of accidents, conclusions are drawn whether current self-propelled vehicles provide the safety level that drivers and society expect from these vehicles. The reconstruction of the accident process is illustrated with the help of a vehicle simulation program, with the resultant parameters being given a special emphasis, in particular to the avoidance of the accident.
The design of experiment (DoE) is a methodology originated from early 1920s when Fisher’s papers created the analysis of variance and first known experimental designs: latin squares. It is focused on a construction of empirical models based on measurements obtained from specifically structured and driven experiments. Its development resulted in the constitution of four distinctive branches recognized by the industry: factorials (full or fractional), Taguchi’s robust design, Shainin’s Red-X®and a response surface methodology (RSM). On one hand, the well-known success stories of this methodology implementations promise great benefits, while on other hand, the mathematical complexity of mathematical and statistical assumptions very often lead to improper use and wrong inferences. The possible solution to avoid such mistakes is the expert system supporting the design of experiments and subsequently the analysis of obtained data. The authors propose the outline of such system and provides the general analysis of the ontology and related inference rules.
Since G.E.P. Box introduced central composite designs in early fifties of 20th century, the classic design of experiments (DoE) utilizes response surface models (RSM), however usually limited to the simple form of low-degree polynomials. In the case of small size datasets, the conformity with the normal distribution has very weak reliability and it leads to very uncertain assessment of a parameter statistical significance. The bootstrap approach appears to be better solution than - theoretically proved but only asymptotically equal - t distribution based evaluation. The authors presents the comparison of the RSM model evaluated by a classic method and bootstrap approach.