bluuebunny/crossref_metadata_2025 huggingface dataset:
Caffeine supplementation improves countermovement jump in youth soccer players: a pilot study
Authors: Hernández-Camacho Juan Diego , Vázquez-Carrión Javier , Fuentes-Lorca Elena , Moya-Amaya Heliodoro
Published: July 2017

Introduction: The objective of this study was to analyze the effect of caffeine ingestion in soccer performance, particularly in the countermovement jump test (CMJ).Material and methods: A total of 17 players from a U-19 amateur Spanish team participated in this pilot study. A double-blind placebo-controlled randomized experimental design was used in 2 different sessions (1.5 hour per session) separated by 1 week. CMJ was collected at the beginning and at the end of sessions; Rating of Perceived Exertion (RPE) was recorded. Players ingested caffeine or placebo at the beginning of session (minute 0 of session), providing a total of 4 mg of caffeine or a placebo per kg of body mass. Side effects from caffeine and placebo ingestions were analyzed. The effect sizes (ES) were calculated using values for Cohen’s and Quantitative differences were assessed qualitatively (QA).Results: The jump height with caffeine supplementation at the beginning of training was 37.03 (±3.87) cm and at the end was 39.35 (±4.05) cm, obtaining significant improvements (p<0.05; ES: 0.56; QA: 99/1/0). Significant differences on CMJ at the end of the training session between caffeine and placebo groups were observed (39.35 [±4.05] cm vs. 36.85 [±3.15] cm; p<0.05; ES: 0.65; QA: 0/1/99). Significant differences on RPE between groups were observed. A non-significant tendency to suffer more side effects with caffeine ingestion was obtained.Conclusions: This study shows how the ingestion of 4 mg of caffeine per kg of body mass could be an ergogenic aid to improve soccer performance. However, further studies with bigger soccer players sample would be necessary to refute the present results.
Obstacles and difficulties implementing the lean philosophy in Brazilian enterprises
Authors: Pereira Caroline Morito , Anholon Rosley , Batocchio Antonio
Published: July 2017

The success of Lean Manufacturing does not come down only to its application tools; it is an accomplishment of the entire leadership and workers dedicated to putting the system’s essence into practice, along with its underlying values and philosophy. In this context, the main purpose of this study is to present an analytical research in terms of the obstacles and difficulties faced by Brazilian companies to implement the Lean Manufacturing. Through a literature review of the annals of ENEGEP (the Brazilian Production Engineering Conference), this research concluded that the main obstacles and difficulties of such implementation fall under seven lines: 1) difficulties using the tool; 2) operational resistance; 3) cultural differences; 4) slow response to market; 5) lack of top/senior management involvement; 6) lack of middle management support, 7) lack of resources to invest. This article stands as a useful source for further studies about the Lean Manufacturing system.
Worker-Recovered Companies in Brazil: self-management process assessment by applying multi-criteria decision support tools
Authors: Araujo Fernanda Santos , Oliveira Vicente Nepomuceno , Alvarez Denise , Costa Helder
Published: July 2017

Company recovery is a practice developed by workers who, in the imminence of becoming unemployed, negotiate or fight for access to the means of production of bankrupting companies, and start to manage them collectively, guided by the principles of self-management.  Nevertheless, how to assess self-management in worker-recovered companies (WRCs)? The criteria selected by a bibliographic review on the concept of self-management were used in dealing with the data collected by the Brazilian WRCs national mapping. A multi-criteria decision support tool was used to build a model for analyzing and classifying the companies in three categories related to their form of management. The multi-criteria approach allowed to create an assessment of self-management practices in the WRCs studied.
Descriptive and comparative study of the purchasing activity: a case study in a food company
Authors: Endo Letícia Miyuki Aida , Cerqueira Murillo Costa , Nery da Silva Gabriel , Sena Nery Laiane Aparecida Soares , Kawamoto Júnior Luiz Teruo
Published: July 2017

In a scenario of economic and political instability, many companies have being affected by a sense of uncertainty, both small and large companies. In this context, Logistics seeks, among other things, to reduce costs, improve processes and align the supply chain with company strategies. The purchasing sector is increasingly seen as a strategic agent in organizations, not only contributing to cost reduction, but also gaining in terms of productivity, economy and quality. This study aims to analyze and describe the purchasing procedures of a small food company located in the State of São Paulo, and compare it with the literature to see whether there is a matching or a gap between them. The procedure adopted by the study is the case study, based on three pillars: interviews, non-participant observations and documental analysis. The results showed that the company adopts many procedures described in the literature in its purchasing activities, and, with that, it has been performing strategically the purchasing activity and keeping itself competitive within the market; as well as currently there is not a gap between literature and practice.
A State of art on economic production quantity models
Authors: Borade Atul B. , Ardak Pankaj S.
Published: July 2017

Economic ordering quantity is a commonly accepted inventory management model. Its variant economic production quantity (EPQ) model is also a widely researched inventory model. The number of researchers had developed the EPQ model by considering different parameters, such as shortage, backorder, setup cost, deterioration, constant or linear or power form of the demand, rework, scrap, inspection, machine breakdown, etc. The objective of this paper is to review the literature, identify the gap in literature, develop and expand the knowledge base regarding EPQ models. This state of art paper would act as a guideline for researchers. The wide spectrum of the subject provides interesting future research problems.
Distance learning for training business game tutors
Authors: Marinho Mariana de Toledo , Rodrigues José de Souza , Zambon Kátia Livia
Published: July 2017

This work is the result of research that proposes the incorporation of Distance Learning into a Business Game as a strategy to enhance tutor training, considering entrepreneurship difficulties faced by public school teachers. Part of the problem could be attributed to subject type, because, in general, it is not common to find entrepreneurship on school curricula. The Distance Learning (DL) activities were developed using the Moodle platform and were structured by topic to increase educational flexibility and achieve a better balance between individual reflection and online discussion. It was developed in four steps: course content development; course evaluation by computer technicians; course restructuring based on course evaluation by computer technicians; and course evaluation by teachers from the public school system. A preliminary test was performed with informatics technicians to technically evaluate the learning environment. Based on this, the course was restructured, applying corrections and adjustments in order to improve environment usability. After corrections, a final test was conducted with public school system teachers to analyze user perception, which gave a positive result. Virtual learning environment evaluation is complex and multidisciplinary, requiring the technical knowledge of internet programming and a conceptual knowledge of education, especially in the field of learning. When the evaluation done by teachers was examined it was found that deficiencies pointed out by computer technicians had been resolved, giving a positive rating. This current research concludes that DL can improve the use of games, because it is possible to structure content related to the learning gaps of specific groups of students. In this respect, the use of games results can guide the development of content.
Improving operational measures in a financial institute call center: a case study
Authors: Cohen Yuval , Rozenes Shai
Published: July 2017

This article presents a case study that shows the impact of a proposed method of performance measures in a call center service system in one of the largest financial institutions in Israel. It proposes a policy for load-reduction in the peak hours coupled with an improvement in the automated routing of customers’ calls. The case study shows the system's current state, and offers improvements to shorten the overall service time while increasing utilization of service personnel in order to decrease the abandon rate (AR) and increase service quality. The article starts by introducing the financial institute and its telephone service structure, the unique characteristic of the current service system, the different types of customers and their characteristics, the utilization of the system and emphasizes the phone call duration and AR. In addition, the article shows a simulation of the current state with an analysis of current service. It compares the current system with an alternative service system that aims at improving the main performance measures including average wait time (AWT), service personel utilization time, and customer abandon rate. The proposed system includes additional "back office" with a callback system to reduce churn rate, and improved the IVR routing. The proposed service system was simulated and all the service measurement was tested statistically. The results indicated a significant improvement in terms of service measurements between the current and the proposed system. Operators’ utilization increased, while abandoning rate decreased significantly.
Development of a scenario prospecting model with the use of multicriteria decision aiding: Importance of environmental variables
Authors: Moraes Vieira José Artur , Simões Gomes Carlos Francisco , Engel Braga Igor
Published: July 2017

The significance of using resources optimally comes from its increasingly present scarcity, whether they are related to the environment, term, financial resources, and political or legal difficulties. This study proposes the use of prospective scenarios, considering multiple and uncertain alternatives. It can be an essential tool for the strategic planning process of organizations. The motivation of the subject studied is the possibility to contribute to the expansion of the corporate strategic planning vision and towards social welfare, related to the commitment of companies to society, since it proposes a model for prospecting scenarios supported by multicriteria decision aiding (MDA) approach, necessarily considering variables related to Corporate Social Responsibility and its nuances. As a result, it is expected to fill the identified gap, which places prospecting scenarios as an empirical tool that deals only with economics and a single future possibility. For further research the application of the model in an actual case is suggested, still raising important questions such as: is there a real contribution with the application of prospective scenarios? Is this tool applicable to any type of company? Who are the stakeholders and how do you measure the effectiveness of this tool?
Příroda nás živí, země nás nese
Authors: Olšovský Jiří
Published: July 2017

We need a truly new vision, and a deeper philosophical reflection. A completely new genuine reconciliation of the human community to finally find the authentic alliance of man with nature. Humans have been separated from nature, and it is time to return, or the hidden power of nature will destroy us. What could save us is the essential gratitude for being itself, in practice manifested as a care for oneself and an environment, the Earth, and all the elements that carry the world. Our (anthropocentric) attitudes towards the world and nature will change - to find true alliances with non-human beings, unity with cosmos. Thus, a new reflection is needed that will liberate from the insatiable desires and the profligate profitable behaviour. The truth of the world, the truth of being will be revealed to us if we do not surrender to various speculative speculations and malicious constructions of today.
Hawthorne’s Rome – A city of evil, political and religious corruption and violence
Authors: Rabinovich Irina
Published: July 2017

Hawthorne’s Rome is the home of dark and evil catacombs. It is a city haunted by evil spirits from the past that actively shape the romance’s plot. Rome’s dark gardens, endless staircases, hidden corners and vast catacombs, as well as the malodorous Jewish ghetto, affect Donatello’s and Miriam’s judgment, almost forcing them to get rid of the Model, Miriam’s persecutor. Hawthorne’s narrator’s shockingly violent, harsh and seemingly anti-Semitic description of the ghetto in Rome is just one among many similarly ruthless, and at times offensive, accounts of the city wherein Hawthorne situates his last completed romance, The Marble Faun. Hawthorne’s two-year stay in Rome in 1858-59 sets the scene for his conception of The Marble Faun. In addition to providing Hawthorne with the extensive contact with art and artists that undoubtedly affected the choice of his protagonists (Kenyon, a sculptor; Hilda and Miriam, painters), Italy exposed Hawthorne to Jewish traditions and history, as well as to the life of Jews in the Roman ghetto. Most probably it also aroused his interest in some of the political affairs in which Italian Jews were involved in the 1840s and 50s. This historical background, especially the well-publicized abduction and conversion of a Jewish child, Edgardo Mortara, in 1858 provides important political and cultural background for Hawthorne’s portrayal of Miriam in The Marble Faun.
Aesthetic distance as a form of liminality in selected short stories of American literature
Authors: Čechová Natália
Published: July 2017

Aesthetic distance is a phenomenon that has attracted a considerable amount of attention, especially since the first works of postmodernism came to light. Aesthetic distance is based on creating such works which - using certain artistic tools and techniques - break the illusion and thus inhibit readers from immersing themselves in the literary world portrayed in the work they read. As a result, aesthetic distance creates a liminal space, or an invisible but consciously perceivable border between reality, i.e. the world we live in and fiction, i.e. the world we want to relocate to and enjoy during the reading process. The paper is based on an article by Bjorn Thomassen, in which he presents several types of liminality and states that the typology is not final. My aim is to prove that liminality can occur in literature as well, particularly in works built on aesthetic distance. In this matter, I focus on the reception theory of Wolfgang Iser, who studies literary texts from three perspectives: the text, the reader and the communication between the two. The theory is applied to selected short stories of American literature, which contain illusion-breaking features and thus may be viewed as liminal spaces.
The use of X-ray computed microtomography for graptolite detection in rock based on core internal structure visualization
Authors: Kaczmarek Łukasz , Kozłowska Anna , Maksimczuk Michał , Wejrzanowski Tomasz
Published: July 2017

This paper presents for the first time X-ray computed microtomography (μCT) analysis as a technique for Silurian graptolite detection in rocks. The samples come from the Jantar Bituminous Claystones Member of the Opalino core, Baltic Basin, northern Poland. Images were obtained with spatial resolution of 25 μm, which enabled the authors to create a 3-D visualization and to calculate the ratio of fissure and graptolite volume to the total sample volume. A set of μCT slices was used to create a 3-D reconstruction of graptolite geometry. These μCT slices were processed to obtain a clearly visible image and the volume ratio. A copper X-ray source filter was used during exposure to reduce radiograph artifacts. Visualization of graptolite tubaria (rhabdosomes) enabled Demirastrites simulans to be identified. Numerical models of graptolites reveal promising applications for paleontological research and thus for the recognition and characterization of reservoir rocks.
Limpet-shaped gastropods of the genus Diodora (Vetigastropoda: Fissurellidae) from the Middle Miocene of Western Ukraine
Authors: Dell’Angelo Bruno , Sosso Maurizio , Anistratenko Olga , Anistratenko Vitaliy
Published: July 2017

The genus Diodora Gray, 1821 is widely represented in the Middle Miocene of the Central Paratethys with specimens usually attributed to D. graeca (Linnaeus, 1758) or D. italica (Defrance, 1820), well-known recent species of the Atlantic / Mediterranean Basin. In samples from the Upper Badenian of Western Ukraine we found two clusters of Diodora specimens, showing a similarity with these species, but a review of shell diagnostic characters using a statistical approach has revealed their clear conchological separateness. The first species from Varovtsi and Horodok is attributed herein to D. nodosa (Eichwald, 1830), whereas the second species from Maksymivka is described as a new species, D. stalennuyi sp. nov. We consider that these molluscs inhabited the Polish-Ukrainian marginal part of the Late Badenian Basin. Detailed descriptions of the protoconch and teleoconch morphology of the taxa involved, including SEM images, are presented.
Early Bashkirian Rugosa (Anthozoa) from the Donets Basin (Ukraine). Part 5. The Family Bothrophyllidae Fomichev, 1953
Authors: Fedorowski Jerzy
Published: July 2017

Four genera (one new, one questionable), seven named species (five new) and five taxa left in open nomenclature are described from uppermost Serpukhovian (Limestone D53) to middle Bashkirian (Limestone G11) strata. A new genus: Nina and the new species: Bothrophyllum kalmyussi, B. gorbachevensis, Nina donetsiana, N. dibimitaria and N. magna are introduced. The genus Cystilophophyllum Fomichev, 1953 is redefined and transferred to the Family Bothrophyllidae. Three general topics discussed in the Considerations are: 1. The taxonomic value of the microstructure of the septa and the necessity for a distinction between that character and diagenetic alterations; 2. Depositional conditions, under which the rugose coral skeletons were deposited; 3. The similarity of skeletal constructions vs. relationships in some taxa of the Subfamily Dibunophyllinae Wang, 1950 and the Family Bothrophyllidae Fomichev, 1953. The lack of final conclusions in the matter of the relationships is due to the incompleteness and restricted number of specimens studied herein and the incomplete investigations of a great majority of the earlier described bothrophyllid taxa.
The Effect of the Use of Technological Lubricants Based on Vegetable Oils on the Process of Titanium Sheet Metal Forming
Authors: Więckowski W. , Dyja K.
Published: July 2017

The paper evaluates the drawability of titanium sheet metal Grade 2, with the focus on friction conditions that are present in the sheet metal forming process. The study aims to present the results of the examinations of the friction coefficient during a strip drawing test. The focus of the experiment was on lubricants based on vegetable oils i.e. rapeseed oil, sunflower oil and olive oil. Boric acid was used to improve the lubricating properties of vegetable oils. The results of numerical simulations of the process of forming a cover with stiffening components made of grade 2 titanium sheet metal was also presented. The numerical simulation was carried out using the FEM method with PAMStamp 2G software. The effect of conditions of friction between the sheet metal and tool parts and pressure force of the blank holder on the forming process were investigated. Numerical calculations were performed with consideration for the phenomenon of material strain hardening and anisotropy of plastic properties of the sheet metal formed. The analysis of the deformations and reduction in wall thickness of the drawn parts can be used for determination of the effect of changes in selected parameters on the process of drawn part forming. The quality of drawn parts was assessed based on the shape inaccuracy determined during simulation of forming. The inaccuracy depended on the conditions of the process and strength properties of the titanium sheet metal.
Diode Laser Surface Alloying of Armor Steel with Tungsten Carbide
Authors: Janicki D. , Górka J. , Kwaśny W. , Gołombek K. , Kondracki M. , Żuk M.
Published: July 2017

Metal matrix composite (MMC) surface layers reinforced by WC were fabricated on armor steel ARMOX 500T plates via a laser surface alloying process. The microstructure of the layers was assessed by scanning electron microscopy and X-ray diffraction.

The surface layers having the WC fraction up to 71 vol% and an average hardness of 1300 HV were produced. The thickness of these layers was up to 650 μm. The addition of a titanium powder in the molten pool increased the wettability of WC particles by the liquid metal in the molten pool increasing the WC fraction. Additionally, the presence of titanium resulted in the precipitation of the (Ti,W)C phase, which significantly reduced the fraction of W-rich complex carbides and improved a structural integrity of the layers.
Microstructural and Mechanical Study of Inconel 625 – Tungsten Carbide Composite Coatings Obtained by Powder Laser Cladding
Authors: Huebner J. , Rutkowski P. , Kata D. , Kusiński J.
Published: July 2017

This study focuses on the investigation of fine (~0.54 μm) tungsten carbide particles effect on structural and mechanical properties of laser cladded Inconel 625-WC composite. Three powder mixtures with different Inconel 625 – WC weight ratio (10, 20 and 30 weight % of WC) were prepared. Coatings were made using following process parameters: laser beam diameter ø ≈ 500 μm, powder feeder rotation speed – 7 m/min, scanning velocity – 10 m/min, laser power – 220 W changed to 320 W, distance between tracks – 1 mm changed to 0.8 mm. Microstructure and hardness were investigated. Coatings produced by laser cladding were crack and pore free, chemically and structurally homogenous. High cooling rate during cladding process resulted in fine microstructure of material. Hardness improved with addition of WC from 396.3 ±10.5 HV for pure Inconel 625, to 469.9 ±24.9 HV for 30 weight % of WC. Tungsten carbide dissolved in Inconel 625 which allowed formation of intergranular eutectic that contains TCP phases.
Estimation of the Effect of Production Parameters on Mechanical Properties of Sintered Steels using ANOVA
Authors: Sułowski M. , Jordan A. , Czarski A. , Matusiewicz P.
Published: July 2017

The object of the study was to assess the influence of selected production parameters of sintered Fe-Mn-Cr-Mo-C steels i.e. chemical composition, sintering temperature, sintering atmosphere and heat treatment on the following mechanical properties: impact toughness, hardness of the surface, tensile strength, bend strength after static tensile tests.

In the investigations, the general linear model (GLM) of the multivariate analysis of variance ANOVA was used. All assumptions of ANOVA, i.e. randomization of the experiment, the normality of the residuals, equality of variance at different levels have been fulfilled and verified. The predictive strength of the constructed models expressed by the adjusted determination coefficient (R2adj) is at medium or large level – R2adj is in the range from 41.46% to 76.97%. This work is focused mainly on the ANOVA methodology. A wide physical interpretation of the results will be possible after the optimization of the ANOVA models used.
Metallographic Study of the Casting Made from CMSX-6 SC Nickel-Based Superalloy
Authors: Szczotok A.
Published: July 2017

Microstructural characterization is an important tool to optimize the properties of engineering materials. Quantitative metallography is a common technique, which provides three-dimensional estimations of phases and structure elements from two-dimensional images. Metallography has been described as both a science and an art [1].

Superalloys are high-performance alloys which exhibits excellent mechanical strength and creep resistance at high temperatures, good surface stability, and corrosion and oxidation resistance. Temperature and corrosion resistant materials such as nickel-based superalloys are prepared mostly with standard metallographic techniques. However, the results can be significantly improved by using finely graded CMP (chemical mechanical polish) polishing solutions on a high napped polishing pad.

Sample preparation requires a certain degree of skills and experience, due to the high chemical resistance of most superalloys. Some chemical solutions are able to dissolve theγmatrix and recover theγ'residue, and some others solutions can be used to obtain a contrary effect – dissolve theγ'phase precipitates and recover theγmatrix residue. The aim of the presented research is to describe qualitatively and quantitatively the as-cast microstructure of CMSX-6 SC superalloy. The author’s attention has been concentrated on theγ'phase precipitates morphology. The results of using optical and scanning electron microscopy (SEM) are presented.
The Impact of the Thickness of the Ceramic Shell Mould on the (γ + γ′) Eutectic in the IN713C Superalloy Airfoil Blade Casting
Authors: Szczotok A. , Nawrocki J. , Pietraszek J.
Published: July 2017

In the study the wall thickness of ceramic shell mould influence on (γ+γ′) eutectic in the IN713C nickel-based superalloy airfoil blade casting was described.

Two castings formed as a blade from two wax pattern assemblies were analysed. In the experiment in one pattern the thick ceramic layer was obtained on pressure side and in another one on suction side of the airfoil blade. The microstructure of the cross-sections of the castings were observed on polished and etched metallographic specimens. The microstructure and phases chemical compositions of specimens was analyzed by using the scanning electron microscope Hitachi S-4200 equipped with EDS. It was established, that wall thickness of ceramic shell mould affect size, shape and volume fraction of (γ+γ′) eutectic islands in airfoil blade made from IN713C superalloy.

The analysis was provided in accordance to the typical statistical methodology [1].
The Application of Acoustic Emission and Artificial Neural Networks in an Analysis of Kinetics in the Phase Transformation of Tool Steel During Austempering
Authors: Łazarska M. , Woźniak T.Z. , Ranachowski Z. , Ranachowski P. , Trafarski A.
Published: July 2017

During the course of the study it involved tool steel C105U was used. The steel was austempered at temperatures of 130°C, 160°C and 180°C respectively. Methods of acoustic emission (AE) were used to investigate the resulting effects associated with transformations and a large number of AE events were registered. Neural networks were applied to analyse these phenomena. In the tested signal, three groups of events were identified of: high, medium and low energy. The average spectral characteristics enabled the power of the signal spectrum to be determined. After completing the process, the results were compiled in the form of diagrams of the relationship of the AE incidence frequency as a function of time. Based on the results, it was found that in the austempering of tool steel, in the first stage of transformation midrib morphology is formed. Midrib is a twinned thin plate martensite. In the 2nd stage of transformation, the intensity of the generation of medium energy events indicates the occurrence of bainite initialised by martensite. The obtained graphic of AE characteristics of tool steel austempering allow conclusions to be drawn about the kinetics and the mechanism of this transformation.
The Effects of Finish Rolling Temperature and Niobium Microalloying on the Microstructure and Properties of a Direct Quenched High-Strength Steel
Authors: Kaijalainen A. , Vähäkuopus N. , Somani M. , Mehtonen S. , Porter D. , Kömi J.
Published: July 2017

This paper comprehends the effects of finish rolling temperature (FRT) and Nb-microalloying on the microstructural evolution and resultant properties of a low carbon direct quenched steel in the yield strength category of ≥900 MPa. Results indicate that a decrease in FRT close to Ar3temperature significantly influenced the microstructure following phase transformation, especially at the subsurface (~50-400 μm) of the rolled strip. On decreasing the FRT, the subsurface microstructure revealed a fine mixture of ferrite and bainite obviously as a result of strain-induced transformation, whereas the structure at the centreline remained essentially martensitic. Further, Nb-microalloying promoted the formation of ferrite and bainite even at higher FRTs, thus influencing the mechanical properties. The microstructures of the hot-rolled strips were further corroborated with the aid of CCT diagrams.
Microstructural and Mechanical Characterization of Electron Beam Welded Joints of High Strength S960QL and Weldox 1300 Steel Grades
Authors: Błacha S. , Węglowski M.S. , Dymek S. , Kopyściański M.
Published: July 2017

The paper shows the results of metallographic examination and mechanical properties of electron beam welded joints of quenched and tempered S960QL and Weldox 1300 steel grades. The aim of this study was to examine the feasibility of producing good quality electron beam welded joints without filler material.

Metallographic examination revealed that the concentrated electron beam significantly affects the changes of microstructure in the weld and the adjacent heat affected zone (HAZ) in both steel grades. The microstructure of the welded joints is not homogeneous. The four zones, depending on the distance from the weld face, can be distinguished. Basically, the microstructure of the weld consists of a mixture of martensite and bainite. However, the microstructure of HAZ depends on the distance from the fusion line. It is composed of martensite near the fusion line and a mixture of bainite and ferrite in the vicinity of the base material.

Significant differences in mechanical properties of the welded joints were observed. For a butt welded joint of the S960QL steel grade the strength is at the level of the strength of the base material (Rm = 1074 MPa). During the bending test the required angle of 180° was achieved. The impact strength at −40°C was 71,7 J/cm2. In the case of the Weldox 1300 steel grade butt welded joints exhibit high mechanical properties (Rm = 1470 MPa), however, the plastic properties are on the lower level than for the base material.
Fabrication and Crystal Structure of Sol-Gel Deposited BST Thin Films with Compositional Gradient
Authors: Czekaj D. , Lisińska-czekaj A. , Plewa J.
Published: July 2017

In the present research technology of compositionally graded barium strontium titanate Ba1-xSrxTiO3thin films deposited on stainless steel substrates by sol-gel spin coating followed with thermal annealing atT= 650°C is reported. Results of thermal behavior of the sol-gel derived powders with compositions used for fabrication of graded structure (i.e. with Sr mole fractionx= 0.5, 0.4 and 0.3) are described. X-ray diffraction studies of the phase composition and crystal structure of such complex thin film configuration are given. It was found that gel powders exhibited a large total weight loss of about Δm≈ 44-47%. Three stages of weight loss took place at temperature ranges: belowT≈ 300°C, at ΔT≈ 300-500°C and betweenT= 600°C andT= 800°C. Phase analysis has shown that the dominating phase is Ba0.67Sr0.33TiO3compound while the second phase is Ba0.7Sr0.3TiO3or Ba0.5Sr0.5TiO3for “up-graded” and “down-graded” structure, respectively.
Study of Composite Insulator Sheds Subjected to Wheel Test
Authors: Mackiewicz M. , Mikulski J.L. , Wańkowicz J. , Kucharski S. , Ranachowski P. , Ranachowski Z.
Published: July 2017

The paper presents investigation of the properties of the surface and the material stiffness – flexibility of series of samples taken from the sheds of the composite insulators. The insulators were previously subjected to wheel test. The wheel test and 1000 h salt fog test are regarded as alternative examination of the material resistance to the effects of electrical surface discharges. There were investigated two series of the samples of the composite insulators sheds. Examined specimens, made of HTV silicone rubber, were taken from the sheds of medium-voltage composite insulators of two different manufacturers. Insulators of both types passed the 1000 h salt fog test without reservation. Meanwhile, the wheel test can provide a basis for better distinguishing between physical properties of the tested materials. In the case of the insulators of one of the manufacturers the wheel test result was negative. Cross puncture effect of the sheds took place in several places. In addition, sheds were covered with dark coating of varying thicknesses. The results of the study indicated a significantly stronger influence of electrical and temperature factors on the sheds under investigations during the wheel test than in the case of the 1000 h salt fog test. It can be stated that these tests cannot be considered as alternative and it seems that wheel test enables better distinguishing between properties of the materials.
Microstructure and Soft Magnetic Properties of Fe-Zr-(Pt)-Nb-Cu-B Amorphous Alloys
Authors: Gondro J. , Błoch K. , Nabiałek M. , Walters S.
Published: July 2017

This paper presents the results of investigations into the microstructure and magnetic properties of Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8and Fe81Pt5Zr7Nb1Cu1B5alloys. The alloys were investigated in their as-quenched state, in the form of thin ribbons with approximate dimensions as follows: width 3 mm and thickness 20 μm.

The investigations were performed utilizing Mössbauer spectrometry and X-ray diffractometry. Also, an evaluation of the low-field magnetic susceptibility and measurements of the magnetization versus temperature and magnetizing field were performed.
Thermal Stability of AA1050 Aluminum Alloy after Equal Channel Angular Pressing
Authors: Koprowski P. , Bogucki R. , Bieda M. , Kawałko J. , Sztwiertnia K.
Published: July 2017

The annealing behavior of AA1050 aluminum alloy deformed by equal-channel angular pressing (ECAP) was studied experimentally. The material was subjected to extrusion through die with channels intersecting at an 90° angle. Samples were pressed for up to 8 passes using route BC, then cut into slices and subsequently annealed for 1 hour at temperatures from 100°C to 350°C. Hardness measurements were performed on each slice. Microstructure of material was analyzed in the longitudinal section by means of Electron Backscatter Diffraction system in a scanning electron microscope (EBSD/SEM). From the obtained sets of Kikuchi diffraction patterns orientation maps and Image Quality maps were determined. Grain size, disorientation distributions and crystallographic texture were also estimated. ECAP caused significant improvement of hardness, with stabilization after 4 passes. Refinement of microstructure was obtained with the increasing amount of passes. Material properties were stable during annealing at temperatures lower than 150°C. Annealing at higher temperatures caused a decrease in hardness corresponding to an increase of the grain size.
TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method
Authors: Rozmus-Górnikowska M. , Blicharski M.
Published: July 2017

The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT) method. Investigations were primarily carried out through transmission electron microscopy (TEM) on thin foils prepared by FIB (Focus Ion Beam).

The chemical analysis demonstrated that the amount of certain elements (Fe, Ni, Cr, Mo, Nb) in the transition zone between the base material and the weld overlay changes quickly, from the composition of the steel to the composition of the composite zone. STEM and TEM investigations revealed that two areas are clearly visible in the transition zone. In the narrow band close to the fusion boundary where plates are clearly visible and theMstemperature is higher than room temperature, electron diffraction analyses show reflections of martensite and austenite. Moreover, the crystallographic relations between martensite and austenite can be described by the Kurdjumov-Sachs (K-S) relationship$\{ 110\} _{\alpha '} ||\{ 111\} _\gamma < 1\bar 11 > _{\alpha '} || < 1\bar 10 > _\gamma $). The microstructure of the part of the transition zone with anMstemperature lower than room temperature as well as that of the composite zone is austenite. The investigations proved that the width of the martensitic area can be significantly limited by using the CMT technique for weld overlaying.
Investigation of the Ultrafine-Grained Structure Formation under Different Strain Rates
Authors: Kováčová A. , Kvačkaj T. , Bidulský R. , Bidulská J. , Kočiško R. , Dutkiewicz J. , Lityńska-Dobrzyńska L.
Published: July 2017

The present paper deals with a study on formation of specific substructural features in OFHC copper processed by equal-channel angular pressing (ECAP) considering different strain rate conditions. Since two mechanical tensile testing equipments were being used, strain rate response could be studied in a wide range (both in static and dynamic regimes). Moreover, the copper before tensile testing was subjected to drawing and ECAP, separately, which allows to study the influence of both structural and substructural features (CG vs. UFG structure). Considering the static regime, it was found that UFG materials have advanced properties, showing higher strength and ductility in comparison to their CG counterparts. However, this is valid only to the critical value of the strain rate. In the dynamic regime, mathematical linearized results imply that ultimate tensile strength in samples processed by ECAP increases twice every 10 s−1rising, however, they lost approximately the same plastic properties than samples after drawing. Differences in the progress of mechanical properties are related to specific structural and substructural features evolved in the material during ECAP processing. Above mentioned features were studied in detail by methods of transmission and scanning electron microscopy (TEM, SEM).
Investigations of Temperatures of Phase Transformations of Low-Alloyed Reinforcing Steel within the Heat Treatment Temperature Range
Authors: Kargul T.
Published: July 2017

The paper presents the results of DSC analysis of steel B500SP produced in the process of continuous casting, which is intended for the production reinforcement rods with high ductility. Studies were carried out in the temperature range below 1000°C in a protective atmosphere of helium during samples heating program. The main objective of the study was to determine the temperature range of austenite structure formation during heating. As a result of performed experiments:Ac1s,Ac1f– temperatures of the beginning and finish of the eutectoid transformation,Ac2– Curie temperature of the ferrite magnetic transformation and the temperature Ac3of transformation of proeutectoid ferrite into austenite were elaborated. Experimental determination of phase transformations temperatures of steel B500SP has great importance for production technology of reinforcement rods, because good mechanical properties of rods are formed by the special thermal treatment in Tempcore process.
Influence of Cooling Conditions on a Slab’s Chill Zone Formation During Continuous Casting of Steel
Authors: Drożdż P.
Published: July 2017

The cooling conditions of a slab during continuous casting of steel have an impact on the crystalline structure formation. Numerical methods allow real processes to be modelled. Professional computer programs are available on the market, so the results of their simulations allow us to understand the processes that occur during the casting and solidification of the slab. The study attempts to evaluate the impact of the intensity of the secondary cooling on the chilled zone size. The calculations show the differences in the structure of a slab cast with various speeds while maintaining industrial cooling parameters during operation of a continuous casting machine.
Calorimetric Measurements of Ga-Li System by Direct Reaction Method
Authors: Dębski A.
Published: July 2017

The direct reaction calorimetric method was used for the determination of the formation enthalpy of alloys which concentrations correspond to the: Ga7Li2, Ga9Li5, GaLi, Ga4Li5, Ga2Li3, and GaLi2intermetallic phases. The obtained experimental values of the formation enthalpy were: −18.1 ±0.8 kJ/mol at., −26.5 ±0.3 kJ/mol at., −34.7 ±0.3 kJ/mol at., −33.5 ±0.5 kJ/mol at., −32.8 ±0.3 kJ/mol at. and −24.6 ±1.4 kJ/mol at., respectively. After the calorimetric measurements, all the samples were checked by way of X-ray diffraction investigations to confirm the structure of the measured alloys. All the measured values of the formation enthalpy of the Ga-Li alloys were compared with literature data and the data calculated with use of the Miedema model.
Effect of Ga2O3 Nanoparticles Dispersion on Microstructure and Thermoelectric Properties of p-Type BiSbTe Based Alloys
Authors: Kim E.-B. , Koo J.-M. , Hong S.-J.
Published: July 2017

In this study, p-type Bi0.5Sb1.5Te3based nanocomposites with addition of different weight percentages of Ga2O3nanoparticles are fabricated by mechanical milling and spark plasma sintering. The fracture surfaces of all Bi0.5Sb1.5Te3nanocomposites exhibited similar grain distribution on the entire fracture surface. The Vickers hardness is improved for the Bi0.5Sb1.5Te3nanocomposites with 6 wt% added Ga2O3due to exhibiting fine microstructure, and dispersion strengthening mechanism. The Seebeck coefficient of Bi0.5Sb1.5Te3nanocomposites are significantly improved owing to the decrease in carrier concentration. The electrical conductivity is decreased rapidly upon the addition of Ga2O3nanoparticle due to increasing carrier scattering at newly formed interfaces. The peak power factor of 3.24 W/mK2is achieved for the base Bi0.5Sb1.5Te3sintered bulk. The Bi0.5Sb1.5Te3nanocomposites show low power factor than base sample due to low electrical conductivity.
Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method
Authors: Dharmaiah Peyala , Lee C.H. , Madavali B. , Hong Soon-Jik
Published: July 2017

In the present work, we have prepared Bi2Te3nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.
Increasing the Surface Hardness of Cast Iron by Electrodeposition of Borides in Molten Salts
Authors: Al-Azzawi A.H. , Sytchev J. , Baumli P.
Published: July 2017

In this paper the electrodeposition of boron on the surface of cast iron as a coating is applied to increase the hardness and protect the substrate against abrasive wear. The boron containing coating was synthesized by electrodeposition process from a NaCl-KCl (1:1 mol)-10 w%NaF-10w% KBF4molten salt. The effect of electrolysis parameters (temperature and time) on the hardness is presented; the current density varied in the range −37 – −4.5 mA/cm2, allowing perfect coverage of and respect for dimensions. The electrochemical process was carried out at different temperatures (750°C-900°C) and for different periods of time (5-10 hours). Depending on the current density and duration of electrolysis, the deposits consist of FeB or Fe2B. Microhardness measurements across the boride layer indicated very high hardness values (between 1600 and 2100 HV0.05). The structure of the boride layer is linked to its boron content and thermal history: as-deposited coatings present very small grain sizes and can be considered as nearly amorphous.
Enhancement of Life Time of the Dimensionally Stable Anode for Copper Electroplating Applications
Authors: Son Seong Ho , Park Sung Cheol , Lee Man Seung
Published: July 2017

In order to enhance the long-term stability of DSA for copper electroplating process, in the present study, noble metal oxides with excellent electrochemical properties was used and optimum condition was determined the ratio of noble metal oxides, surface pre-treatment of titanium substrate and heat treatment. The effect of the surface pretreatment of titanium substrate and ratio of noble metal oxides were estimated by accelerated test at the highly current density conditions. The lifetime of DSA increase six-fold higher as the oxide thickness of Ta 7 : Ir 3 composition ratio. Under the optimal condition, surface pretreatment led to dramatic increase in the lifetime of DSA.
Crystallization behavior of Zr62Al8Ni13Cu17 Metallic Glass
Authors: Jo Mi Sun , Lee Jin Kyu
Published: July 2017

The crystallization behavior has been studied in Zr62Al8Ni13Cu17metallic glass alloy. The Zr62Al8Ni13Cu17metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson-Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.
Whisker-Like Formations in Sn-3.0Ag-Pb Alloys
Authors: Koncz-Horváth D. , Gergely G. , Gácsi Z.
Published: July 2017

In this study, different types of whisker-like formations of Sn-3.0Ag based alloy were presented. In the experimental process the amount of Pb element was changed between 1000 and 2000 ppm, and the furnace atmosphere and cooling rate were also modified. The novelty of this work was that whisker-like formations in macro scale size were experienced after an exothermic reaction. The whiskers of larger sizes than general provided opportunities to investigate the microstructure and the concentration nearby the whiskers. In addition, the whisker-like formations from Sn-Ag based bulk material did not only consist of pure tin but tin and silver phases. The whisker-like growth appeared in several forms including hillock, spire and nodule shaped formations in accordance with parameters. It was observed that the compound phases were clustered in many cases mainly at hillocks.