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Number of results: 1520
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Abstract

The paper presents the results of the experimental tests of Mg/Al bimetallic bars rolling process in classic and multi-radial modified round-oval-round passes. The bimetallic bar consist of magnesium core, grade AZ31 and aluminium outer layer, grade 1050A. The stocks were round bars with diameter 22.5 mm with an aluminium layer share of 28%. As a result of rolling in four passes, bars of a diameter of about 17 mm were obtained. A bimetallic feedstock was manufactured using an explosive welding method. The use of the designed arrangement of multi-radial modified stretching passes resulted in obtaining Mg/Al bimetallic bars with an uniform distribution of the cladding layer over the bar perimeter and high quality of shear strength between individual layers compared to Mg/Al bars obtained in the classic passes.
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Abstract

Higher active power of a submerged arc furnace is commonly believed to increase its capacity in the process of ferrosilicon smelting. This is a true statement but only to a limited extent. For a given electrode diameter d, there is a certain limit value of the submerged arc furnace active power. When this value is exceeded, the furnace capacity in the process of ferrosilicon smelting does not increase but the energy loss is higher and the technical and economic indicators become worse. Maximum output regarding the reaction zone volumes is one of parameters that characterize similarities of furnaces with various geometrical parameters. It is proportional to d3 and does not depend on the furnace size. The results of statistical analysis of the ferrosilicon smelting process in the 20 MVA furnace have been presented. In addition to basic electrical parameters, such as active power and electrical load of the electrodes, factors contributing to higher resistance of the furnace bath and resulting lower reactive power Px demonstrate the most significant effect on the electrothermal process of ferrosilicon smelting. These parameters reflect metallurgical conditions of ferrosilicon smelting, such as the reducer fraction, position of the electrodes and temperature conditions of the reaction zones.
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Abstract

The effect of CaSiAl modification (43-49% Ca, 43-48% Si, 2% Al) on the non-metallic inclusions and mechanical properties of cast lowcarbon steel is discussed. Tests were carried out on the cast steel with 0.2% C and micro-additives of V and Nb, used mainly for heavy steel castings (e.g. slag ladles). The modifier in an amount of 1.5 and 3 kg / Mg was introduced to the liquid steel before tapping the metal into a ladle. Test ingots of Y type and a weight of 10 kg were cast and then subjected to a normalizing heat treatment. Using light microscopy and scanning electron microscopy, qualitative and quantitative evaluation of the non-metallic inclusions present in as-cast samples was carried out. Additionally, tests of mechanical strength and impact strength were performed on cast steel with and without the different content of modifier. It was found that increasing the modifier addition affected impact strength but had no significant effect on tensile strength and yield strength. The material with high impact strength had the smallest area fraction of non-metallic inclusions in the microstructure (0.20%). The introduction of modifiers changed the morphology of non-metallic inclusions from dendritic to regular and nodular shapes.
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Abstract

Due to the wide range of various sheet metal grades and the need to verify the material properties, there are numerous methods to determine the material formability. One of them, that allows quick determination of sheet metal formability, is the Erichsen cupping test described in the ISO 20482: 2003 standard. In the presented work, the results of formability assessment for DC04 deep drawing sheet metal were obtained by means of the traditionally carried out Erichsen cupping test and compared with the results obtained by using two advanced methods based on vision analysis. Application of these methods allows extending the traditional scope of analysis during Erichsen cupping test by determination of the necking and strain localization before fracture. The proposed methods were compared in order to dedicate appropriate solution for the industrial application and laboratory tests respectively, where the simplicity and reliability are the mean aspects need to be considered when applied to the Erichsen cupping test.
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Abstract

The levitation melting has a potentially wide range of applications, especially in the processing of reactive metals whose contact with the crucible material causes their contamination and damage to the crucible itself. Despite its advantages, levitation melting, already proposed in the 1920s, has not yet found significant use in industrial conditions. This is due to the nature of the electromagnetic field used in previously developed devices. The disappearance of this field in the system axis causes overcoming, in the case of larger charges, surface tension forces and metal leakage from the device. The article contains a comparative analysis of a conventional solution and a newly developed levitation melting device, whose completely different design eliminates the previous weight limit of the charge.
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Abstract

The effect of plastic deformation process on the dissolution rate of biocompatible Mg alloys was investigated. Two biocompatible MgLi1Ca0,2Zn1 and MgLi1Ca1Zn1 alloys were selected for the study. The alloys were deformed on a 100T press at a temperature of 350°C by conventional extrusion and by the equal channel angular extrusion process (ECAE). The grain size analysis showed a high degree of the grain refinement from approximately 110 mm in the initial state to 2.8 mm after the 3rd pass of the ECAE process. Compared to as-cast state, the degree of strengthening has increased after plastic forming. The results of biodegradation tests have shown a significant increase in corrosion rate after both conventional extrusion and ECAE, although after subsequent ECAE passes, this rate was observed to slightly decrease in the MgLi1Ca1Zn1 alloy. Based on the results of macro- and microstructure examinations, the corrosion progress in samples after the extrusion process was described.
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Abstract

Nanostructured thermoelectric materials receiving great attention for its high thermoelectric performance. In this research, nanostructured n-type Bi2Te2.7Se0.3 alloys have prepared using high energy ball milling and followed by spark plasma sintering. Also, we have varied ball milling time to investigate milling time parameter on the thermoelectric properties of n-type Bi2Te2.7Se0.3 powder. The powders were discrete at 10 min milling and later particles tend to agglomerate at higher milling time due to cold welding. The bulk fracture surface display multi-scale grains where small grains intersperse in between large grains. The maximum Seebeck coefficient value was obtained at 20-min milling time due to their lower carrier density. The κ values were decreased with increasing milling time due to the decreasing trend observed in their κL values. The highest ZT of 0.7 at 350 K was observed for 30-min milling time which was ascribed to its lower thermal conductivity. The Vickers hardness values also greatly improved due to their fine microstructure.
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Abstract

In the work results of research on electrodischarge machining (EDM) of titanium alloy Ti10V2Fe3Al with (α + β) structure were presented. Preliminary heat treatment of samples allows to obtain different morphology and volume fraction of the α phase. The main goal of research was to assessment of the material microstructure impact on EDM technological factors (ie. material removal rate, tool wear) and morphology of technological surface layer. Electrodischarge machining is alternative and increasingly used method of titanium alloys machining. Research allowed to indicate the possibilities and limitations of use EDM in this area. It is especially important in the aspect of parts produced for aircraft industry and related requirements for the technological surface layer quality.
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Abstract

In the paper the results of experimental research of the process of flow forming of cylindrical drawpieces were presented. The drawpieces were made of the 3.1 mm thick AMS 5596 sheet by drawing process. Tests were performed on two-roller metal spinning machine of a vertical axis Leifeld SFC 800 V500. The main purpose of this research was to determine the relationship between relative thickness reduction and the mechanical properties of tested material. Knowledge of these dependencies is especially useful in designing machines’ components manufactured by flow forming, in the selection of parameters of realization of this technological process as well. Mechanical properties were determined on the basis of uniaxial tensile of the micro samples obtained from the drawpieces: (I) after cold flow forming, (II) after cold flow forming and in-process heat treatment. Obtained results were shown graphically in the diagrams and their analysis was carried out. In addition, the microstructure of the sheet material tested after drawing and flow forming is presented.
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Abstract

In the paper an analysis of the influence of two parameters on the die wear, i.e. the shape of the die and the backpull with the specified force values has been presented. The conical and curve-profile tools have been selected to determine an influence of the die geometry on its wear, and the backpull force has been tested with the use of conical dies. The research was conducted for the drawing of copper wire by sintered carbide die with a mesh diameter of 3 mm. A fixed draw value of 30% relative gap loss was assumed. The axisymmetric numerical model of the drawing process was built and modeled in the MARC/Mentat commercial program for nonlinear and contact issues. As a result of the tests, wear of the dies according to their shape was determined. In addition, for the conical die the drawing force and the force of the metal pressure on the die using different values of the force of the contraction were calculated, as well as wear of the conical die according to the value of the applied backpull force. It has been shown that in the case of the arc die, the distribution of pressure and stress is more uniform over the entire length of the contact zone compared to the conical die. The highest stress gradients occurred in the area of the transition of the crushing part into the drawing part of the die, which caused that the use of the conical die in this area was more than twice as large as the arc die. In addition, on the example of a conical die, it was shown to what extent the depth of its wear decreases with an increase of the test pull force in the range (0-400) of Newtons.
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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics. Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points. Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.
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Abstract

Ectopic pregnancy constitutes 2% of all pregnancies. In the last decades, due to the rising amount of caesarean sections, new localization of ectopic pregnancy has been observed — caesarean scar pregnancy (CSP). Cesarean scar pregnancy is an iatrogenic disease and a life-threatening condition which frequency will systematically rise. Because of possible serious complications, CSP should be swift ly diagnosed and treated. Th e purpose of this retrospective study was to demonstrate diff erent methods of CSP treatment performed between 2015–2018 in the Clinic of Endocrinological Gynaecology and Gynaecology Jagiellonian University Medical College in Cracow. Th e clinical characteristics, diagnosis, various methods of treatment and clinical outcomes were analysed. Defi nitive algorithm of CSP treatment is still not established. Pharmacological and operative methods are approved while expectant observation is considered unsafe due to possible risk of complications for the patient, including death.
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Abstract

After moving to Italy in 1856, Teofil Lenartowicz, inspired by the great Italian art and supported by the best Florentine artists of the time Giovanni Dupré and Enrico Pazzi, began studying sculpture. Lenartowicz’s sculptures were always connected with literature: his work shows howone influenced the other. It is no accident that his style as a sculptor has been called ‘poetic’ by the critics. The Polish immigrant was fascinated by the Italian Renaissance, and especially by the art of Lorenzo Ghiberti. At the same time, he never forgot about Polish folklore, which played a significant role in his artistic vision. One of the most impressive examples of this intersection of influences is the bas-relief The Holy Workers, complemented by a poem bearing the same name.
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Abstract

This article is an attempt to identify the main themes in the literary work of Zygmunt Haupt, a Polish writer, journalist and painter, who emigrated to the United States in the aftermath of World War II. His writings show a keen awareness of the issue of absence/presence and the related problems of memory traits, identity and literary representation. Drawing on the psychoanalytical criticism of Jacques Lacan and Julia Kristeva and the philosophy of Jacques Derrida, this reading of Haupt’s fi ction, especially his short stories (whose collected edition was published in 2007 under the title The Basque Devil), is a critical reassessment of his work. As a storyteller he excels in the depiction of scenes of terror, desire and the uncanny. The article argues Haupt’s work represents not only a remarkable literary achievement but also offers an interesting study case for critics whose approach is founded on literary theory, psychoanalysis and anthropology.
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Abstract

This article focuses on paralogical figures (amphibology, equivocation, hypallage and syllepsis) in the poems of Jan Zych. Paralogicisms are phrases in which the combination of logical and syntactical form produces an irresolvable semantic conundrum. The article is divided into three parts, each dealing with one aspect of Zych’s handling of the opposition of distance and proximity: air metaphors expressive of the channel of poetic speech; communication by post (letters); and images of the labyrinth. The paralogical figures are discussed in terms of their function as textual building-blocks, a mark of the author’s subjectivity, and an invitation for performative reading. In this way, Zych’s poems, in particular Labirynty (The Labyrinths) are reconstituted as literary performances, analogous to the labyrinthine prose of J. L. Borges and Octavio Paz.
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Abstract

This article, focused principally on the exploration of contingency, the body and disgust in Michał Witkowski’s novel Margot, is also a polemic and a vindication of the book against the barrage of criticism it received from its reviewers. Most of them decided that Margot was a novel about nothing, a haphazard mix of sundry discourses devoid of any linear structure. In fact, several critics blamed the author of giving away both the narrative structure and the plot to capricious contingency. The article takes a fi rm stance against such charges and argues that contingency does not need to be seen as a fault at all. It lies at the heart of the novel and determines the actions of characters, but it plays as important a role in people’s lives outside fi ction. Analysing the ups and down of the main characters (Margot and Wadek Mandarynka), the article explains the function of emotions, the body, the characters’ language and their ideas of sacrum in the legitimization of contingency. A special role in this mechanism is played by disgust. Reactions of disgust are always contingent, or, as Julia Kristeva puts it the abject has the power to terrorize the subject to such extent that he can do nothing but to succumb to contingency. In working out the idea of the contingency of selfhood, the article also draws on Richard Rorty’s approach, and in particular his concept of ironism. The latter is used to classify the main character of Witkowski’s book as a consummate ironist, i.e. a person who tests different languages in which the world can be described in order to pursue his carnal desires. Finally, the article argues that in his novel Witkowski not only brings to light the fortuitous character of the postmodern identity but also creates a heterogeneous language to express it.
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Abstract

This article deals with the rise in the Polish literature of 1970s of a new type of biographical novel, associated with the fi rst post-war generation of writers like Bohdan Zadura, Julian Kornhauser, Adam Zagajewski, Henryk Lothamer, Stanisław Piskor and Donat Kirsch. Their work is subsumed here under the label ‘new fi ction’ primarily because of its literary context, i.e. the late-modern fears and uncertainties culminating in the assumption that literature reached the state of exhaustion. The article argues that the ‘new fi ction’ acquired its distinctive character from a preoccupation with the biographical narrative and a sense of generational identity. The writers who defi ned themselves in these generational terms saw their prospect of following their aspirations and building up authentic lives weighed down by the constricting realities, and, as the article claims, resigned themselves – at best not entirely – to this sad conclusion.
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Abstract

This study is a research reconnaissance into the visual imagery in the poetry of Jan Kochanowski, Poland’s most talented poet before the Romantic Age. Although he was familiar with the technique of ekphrasis and took an interest in emblems, he seems to have been rather sparing in making use of visual potential of the poetic word. However, he does rely on the sense of sight in his epistemological refl ection concerning the problem of knowing God, aesthetics (the experience of beauty) and ethics (the visible order of the world as a guide to proper conduct). The eye also plays a major role in his descriptions of the human psychology, especially love. The sight has a special function in his Treny (Laments), a cycle of elegies written after the death of his baby daughter Urszula in 1579. While addressing the fundamental questions of life and death, Kochanowski draws on visual and aural imagery to convey the devastating pain felt by the father after the death of his beloved child and to question his earlier confi dence in man’s sovereign mind.
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Abstract

This article examines Henryk Sienkiewicz’s proto-racist distinction between the gentry and the commoners in his novel With Fire and Sword (1883–1884). This division, which is believed to be part of the divine world order, credits the commoners with an inferior humanity. It is founded on a set of essentialist beliefs – that social class is inherited, that ‘noble blood’ confers superiority, and that physiognomy bespeaks high birth (you can tell a noblemen or noblewoman by their physical appearance). As the article claims, Sienkiewicz allows no room for a voice questioning those beliefs, let alone exposing their class-bound arbitrariness.
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Abstract

This article examines two collections of manuscripts (previously unanalyzed) with poems which make up Leopold Staff’s debut volume The Dreams of Power. The poet offered them as a gift to Maryla Wolska who deposited them in the Michał Pawlikowski Archives at Medyka. With access to the fi rst, nearly complete, collection we can get an insight into the process of selecting poems for the version that was to go to print (1899–1901). As most of the poems are dated, we are able to establish their sequence and reconstruct the changing concept of their selection. Of special value are twelve poems which had been dropped in the process, and for most part remained unpublished. Each of them is presented briefl y in the article. Apart from making this discovery, the article demonstrates that Leopold Staff’s debut volume as we know it had an earlier version with a set of poems, different from the one that was earmarked for publication under that title.
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