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Open access

Matija Zorc, Aleš Nagode, Milan Bizjak and Borut Zorc

Abstract

In production it is necessary to achieve conditions that lead to the minimum decarburization of a steel product’s surfaces. In this study, the hypo-eutectoid carbon steel C45 was annealed in air in the temperature range T a = 600–1100 °C. The annealing times were between t a = ½ h and t a = 2 h. Different decarburizations occurred in different microstructures: ferrite–pearlite (T a = 600°C and 700 °C, T a < AC1, no visible decarburization); ferrite–austenite (T a = 760 °C, AC1 < Ta < AC3, visible decarburization); austenite at the beginning, ferrite–austenite after the incubation period (Ta = 850 °C, AC3 < T a < 912 °C, visible decarburization); and austenite (T a = 950 °C and 1100 °C, T a > 912 °C, visible decarburization and overheating of steel). The edges were more prone to decarburization and to overheating. Stress relieving, normalizing and annealing before quenching of the steel C45 can be carried out in air.

Open access

Tuuli Kurki, Kristiina Brunila and Elina Lahelma

Abstract

The focus of this paper is to examine how immigrants become constituted as ideal care workers in educational settings. By analysing the everyday practices in two educational contexts in the Helsinki metropolitan area, Finland, the authors explore how these practices that are influenced by the national and transnational immigration and integration policy, regardless of their well-meant actions, can gender and racialise students with immigrant status.

Open access

M. Davarpanah, G. Somodi, L. Kovács and B. Vásárhelyi

Abstract

Understanding the quality of intact rock is one of the most important parts of any engineering projects in the field of rock mechanics. The expression of correlations between the engineering properties of intact rock has always been the scope of experimental research, driven by the need to depict the actual behaviour of rock and to calculate most accurately the design parameters. To determine the behaviour of intact rock, the value of important mechanical parameters such as Young’s modulus (E), Poisson’s ratio (ν) and the strength of rock (σcd) was calculated. Recently, for modelling the behaviour of intact rock, the crack initiation stress (σci) is another important parameter, together with the strain (σ). The ratio of Young’s modulus and the strength of rock is the modulus ratio (M R), which can be used for calculations. These parameters are extensively used in rock engineering when the deformation of different structural elements of underground storage, caverns, tunnels or mining opening must be computed. The objective of this paper is to investigate the relationship between these parameters for Hungarian granitic rock samples. To achieve this goal, the modulus ratio (M R = Ec) of 50 granitic rocks collected from Bátaapáti radioactive waste repository was examined. Fifty high-precision uniaxial compressive tests were conducted on strong (σc >100 MPa) rock samples, exhibiting the wide range of elastic modulus (E = 57.425–88.937 GPa), uniaxial compressive strength (σc = 133.34–213.04 MPa) and Poisson’s ratio (ν = 0.18–0.32). The observed value (M R = 326–597) and mean value of M R = 439.4 are compared with the results of similar previous researches. Moreover, the statistical analysis for all studied rocks was performed and the relationshipbetween M R and other mechanical parameters such as maximum axial strain (εa,max)for studied rocks was discussed.

Open access

Elżbieta D. Ryńska and Maria L. Lewicka

Abstract

Sustainable development has now become an element that is deeply integrated in contemporary architectonic design and urban planning. With the development of a modern designer’s workshop, resilience, passive, ecological, plus energy or nZEB buildings and various smart city issues have to be included in line with more conventional analyses prepared during the design processes. Currently, we also face the emerging theme of the circular economy. This has a great impact, not just on the introduction of circular loops into the flow of building materials, but also on the design approach and management choices. Historic heritage buildings forming part of the building stock must be considered within this new theme. Most existing research deals either with new or modernised buildings, or with the re-use flows of various materials, actually often coming from historic buildings which have passed beyond the limits of repair. This paper shows a different approach to historic buildings where a design was prepared focusing on best choice cases and included a chain of several intertwining approaches, presented against the background of a Polish case study in Warsaw. The aim of this work is to propose a design management procedure to be used when dealing with historic buildings. It follows both the path of a circular economy and of heritage values, emphasising the need to maintain as much of the existing fabric as possible. This analysis is also based on various issues of site research and is followed by historic building case analysis.

Open access

Anna Mastalerz

Abstract

This paper deals with the transformations of (post)industrial towns in Poland, which took place during the transition from a centralised communist economy to liberal capitalism. As a consequence, a number of areas became redundant. These malfunctioning spaces represent serious spatial, social and economic problems. The complex multifaceted nature of towns means, however, that there were no simple solutions leading to immediate improvements. Investments focused on particular, isolated areas appeared to be far from sufficient interventions. Therefore, comprehensive programmes aimed at holistic urban regeneration are more common nowadays. Since local community wellbeing is one of the key factors in these renewal schemes, social participation is a crucial part of the process. This allows residents to have an influence on the regeneration of their town, which (if well carried out) is expected to improve space, economy and quality of life. The above-mentioned issues will be analysed on the basis of a case study of Pabianice, a post-industrial town in the province of Lodz. The aim of this study is to examine the social participation initiatives implemented during the preparation of the Regeneration Programme for Pabianice – to classify them and to compare them with models regarding the level of social involvement and power in the urban regeneration process described in the paper.

Open access

Joanna Wessely-Szponder, Tomasz Szponder, Ryszard Bobowiec and Joanna Michalska

Abstract

Introduction :Antimicrobial peptides (AMP) are a large group of innate immune effectors, which apart from antimicrobial activity show immunomodulative properties. Platelet-rich plasma (PRP) is a source of autologous growth factors and is used for stimulation of bone and soft tissue healing. The purpose of this study was to assess the influence of PRP and AMP extract on ovine monocyte-derived macrophage cultures

Material and Methods: The study was conducted on ovine macrophages (Mfs) previously stimulated with LPS or dexamethasone and then with preparations of PRP or AMP. Following activation of the Mfs their morphological and functional features were assessed.

Results: The study revealed pro-inflammatory influence of both examined preparations on Mfs cultures on the basis of morphology, ROS generation and arginase activity. Both preparations enhanced the pro-inflammatory response of cultured Mfs.

Conclusion: This activity may intensify the antimicrobial action of Mfs, however, in cases of excessive and prolonged inflammation the use of these preparations should be limited.

Open access

Krzysztof Kowal, Brygida Ślaska, Adam Bownik, Beata Horecka, Jan Gawor, Anna Śmiech and Angelika Tkaczyk

Abstract

The aim of the study was to find associations between the process of neoplastic transformation and mtDNA mutations/polymorphisms, i.e. factors with potential prognostic significance, and to determine their impact on the biochemical properties, as well as structural, and functional properties of proteins. Blood and neoplastic tissue samples were collected from a 9-year-old Labrador dog with a diagnosed malignant mammary tumour. Next-generation genome sequencing (NGS) of the entire mitochondrial genome was performed using Illumina technology, and bioinformatics analyses were carried out. This is the first report demonstrating the application of NGS in the analysis of the canine mtDNA genome in neoplastic disease. The proposed strategy is innovative and promising. For the first time in the literature, the sequence of 29 genes was analysed to determine their association with the prevalence of tumour. In total, 32 polymorphic loci and 15 mutations were identified. For the first time, as many as 26 polymorphisms and all the mutations have been described to be associated with the neoplastic process in dogs. Most polymorphisms/mutations were found in the D-loop (31% of the polymorphisms and 93% of the mutations) and the COX1 gene sequence (16% of the polymorphisms). Blood or cancer heteroplasmy was noted in 93% of the mutations. Four of the 18 polymorphisms detected in the protein-coding genes were non-synonymous polymorphisms that have not been described in the literature so far (m.T7593C in COX2, m.G8807A in COX3, m.A9911G in ND4L, and m.T13299A in ND5) but resulted in changes in amino acids in proteins. These mutations and polymorphisms can affect mitochondrial functions and may be a result of cell adaptation to the changes in the environment occurring during carcinogenesis. The replacement of “wild type” mtDNA by a mutated molecule may be an important phenomenon accompanying carcinogenesis.

Open access

Liang Jiao, Shengjie Wang, Yuan Jiang and Xuerui Liu

Abstract

In this paper, a fragile ecological area in the Western Tianshan National Nature Reserve of China was selected as the research region, and Picea schrenkiana, which is sensitive to climate change, was selected as the research object. The mean minimum temperature in the growing season of the previous year (May to September) was the main limiting factor for tree radial growth based on an analysis of the relationship between chronological series and climatic factors during 1959–2012 (r = –0.792, p < 0.05). Moreover, the relationship was stable, which showed that tree rings can be used as alternative materials for climate reconstruction. Therefore, the mean minimum temperature of the previous year in 1680–2012 was reconstructed, and the explained variance of the reconstruction equation was 62.7% (R2adj = 62.0%, F = 85.8). The 31 dramatically altered years were found via characteristic year analyses, and extreme changes occurred most often under relatively warm conditions. The mean minimum temperature in the reconstruction shows a clear warming trend by the 11-year moving average of the reconstructive series since the 1950s (the temperature increase: 0.341°C/decade). The driving factors of the mean minimum temperature were influenced mainly by the interaction of solar activity and large-scale atmospheric–oceanic variability, especially the westerly circulations.

Open access

Alaa H. J. Al-Rkaby

Abstract

Waste material such as used tires is increasing every year, which poses environmental problems. However, such material has been used in several geotechnical applications as alternative lightweight backfill in highway embankments and/or behind retaining walls, providing environmental, economic and technical benefits. These applications require knowledge of engineering properties of soil-tire rubber mixtures. The present study aims to show the possibility of tire rubber usage in sand by evaluating the shear strength and deformability of sand mixed with granulated rubber, in weight percentages between 0 and 50%. The tire rubber content was found to influence the stress-strain and deformation behavior of the mixtures. The shear strength of sand mixed with 10% or 20% tire rubber was higher than that measured for sand only. However, the trend for TRC = 30–50% was different. Samples with a rubber content of 30-50% exhibited a rapid decrease in the stress ratio compared with that of sand. The major principal strain at maximum stress ratio was found to increase with increasing tire rubber content. However, it was observed that the lateral strains (minor and intermediate principal strains) of samples reduced significantly with the addition of tire rubber to the sand.

Open access

Fateh Madani and Belkacem Kebli

Abstract

The present article examines the problem related to the axisymmetric torsion of an elastic layer by a circular rigid disc at the symmetry plane. The layer is sandwiched between two similar elastic half-spaces with two penny-shaped cracks symmetrically located at the interfaces between the two bonded dissimilar media. The mixed boundary-value problem is transformed, by means of the Hankel integral transformation, to dual integral equations, that are reduced, to a Fredholm integral equation of the second kind. The numerical methods are used to convert the resulting system to a system of infinite algebraic equations. Some physical quantities such as the stress intensity factor and the moment are calculated and presented numerically according to some relevant parameters. The numerical results show that the discontinuities around the crack and the inclusion cause a large increase in the stresses that decay with distance from the disc-loaded. Furthermore, the dependence of the stress intensity factor on the disc size, the distance between the crack and the disc, and the shear parameter is also observerd.