bluuebunny/crossref_metadata_2025 huggingface dataset:
The diagnostic performance of radiographic criteria to detect aseptic acetabular component loosening after revision total hip arthroplasty
Authors: Abrahams J. M. , Kim Y. S. , Callary S. A. , De Ieso C. , Costi K. , Howie D. W. , Solomon L. B.
Published: April 2017

Aims

This study aimed to determine the diagnostic performance of radiographic criteria to detect aseptic acetabular loosening after revision total hip arthroplasty (THA). Secondary aims were to determine the predictive values of different thresholds of migration and to determine the predictive values of radiolucency criteria.

Patients and Methods

Acetabular component migration to re-revision was measured retrospectively using Ein-Bild-Rontgen-Analyse (EBRA-Cup) and manual measurements (Sutherland method) in two groups: Group A, 52 components (48 patients) found not loose at re-revision and Group B, 42 components (36 patients) found loose at re-revision between 1980 and 2015. The presence and extent of radiolucent lines was also assessed.

Results

Using EBRA, both proximal translation and sagittal rotation were excellent diagnostic tests for detecting aseptic loosening. The area under the receiver operating characteristic (ROC) curves was 0.94 and 0.93, respectively. The thresholds of 2.5 mm proximal translation or 2° sagittal rotation (EBRA) in combination with radiolucency criteria had a sensitivity of 93% and specificity of 88% to detect aseptic loosening. The sensitivity, specificity, positive predictive value and negative predictive value (NPV) of radiolucency criteria were 41%, 100%, 100% and 68% respectively. Manual measurements of both proximal translation and sagittal rotation were very good diagnostic tests. The area under the ROC curve was 0.86 and 0.92 respectively. However, manual measurements had a decreased specificity compared with EBRA. Radiolucency criteria had a poor sensitivity and NPV of 41% and 68% respectively.

Conclusion

This study shows that EBRA and manual migration measurements can be used as accurate diagnostic tools to detect aseptic loosening of cementless acetabular components used at revision THA. Radiolucency criteria should not be used in isolation to exclude loosening of cementless acetabular components used at revision THA given their poor sensitivity and NPV. Cite this article: Bone Joint J 2017;99-B:458–64.
Epidermal growth factor receptor mutations should be considered as a prognostic factor for survival of patients with pathological fractures or painful bone metastases from non-small cell lung cancer
Authors: Willeumier J. J. , van der Hoeven N. M. A. , Bollen L. , Willems L. N. A. , Fiocco M. , van der Linden Y. M. , Dijkstra P. D. S.
Published: April 2017

Aims

This study aims to assess first, whether mutations in the epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma (kRAS) genes are associated with overall survival (OS) in patients who present with symptomatic bone metastases from non-small cell lung cancer (NSCLC) and secondly, whether mutation status should be incorporated into prognostic models that are used when deciding on the appropriate palliative treatment for symptomatic bone metastases.

Patients and Methods

We studied 139 patients with NSCLC treated between 2007 and 2014 for symptomatic bone metastases and whose mutation status was known. The association between mutation status and overall survival was analysed and the results applied to a recently published prognostic model to determine whether including the mutation status would improve its discriminatory power.

Results

The median OS was 3.9 months (95% confidence interval (CI) 2.1 to 5.7). Patients with EGFR (15%) or kRAS mutations (34%) had a median OS of 17.3 months (95% CI 12.7 to 22.0) and 1.8 months (95% CI 1.0 to 2.7), respectively. Compared with EGFR-positive patients, EGFR-negative patients had a 2.5 times higher risk of death (95% CI 1.5 to 4.2). Incorporating EGFR mutation status in the prognostic model improved its discriminatory power.

Conclusion

Survival prediction models for patients with symptomatic bone metastases are used to determine the most appropriate (surgical) treatment for painful or fractured lesions. This study shows that NSCLC should not be regarded as a single entity in such models. Cite this article: Bone Joint J 2017;99-B:516–21.
Slipped capital femoral epiphysis management and the arthroscope
Authors: Accadbled F. , May O. , Thévenin-Lemoine C. , de Gauzy J. Sales
Published: April 2017

Background

In situ pinning of slipped capital femoral epiphysis (SCFE) results in various degrees of deformity of the femoral head-neck junction. Repetitive trauma from cam-type femoroacetabular impingement (FAI) can lead to labral tears and injury to the articular cartilage causing loss of function. Arthroscopic osteoplasty is an alternative to open procedure and to Southwick/Imhäuser-type osteotomies in symptomatic selected cases.

Surgical technique

The amount of bone to be resected has to be carefully planned pre-operatively. Only gentle traction is applied on a well-padded perineal support. A spherical burr is used to gradually resect the prominence. Intra-operative fluoroscopy is very useful when checking adequate reshaping of the head-neck junction is obtained.

Results

Arthroscopy often reveals acetabular cartilage lesions, labrum hyperhemia and fraying which rarely require repair. Arthroscopic osteoplasty provides satisfactory pain relief and, to a lesser extent, restores hip internal rotation.

Conclusion

Arthroscopic osteoplasty is more technically and time-demanding in post SCFE than idiopathic FAI. It requires strong arthroscopic skills and experience in hip arthroscopy. It stands as a reasonable alternative to open procedure or flexion osteotomies in symptomatic FAI post mild to moderate SCFE. It provides pain relief and to a lesser extent restores internal rotation of the hip.
User-Centered Design Practices in Digital Humanities – Experiences from DARIAH and CENDARI
Authors: Thoden Klaus , Stiller Juliane , Bulatovic Natasa , Meiners Hanna-Lena , Boukhelifa Nadia
Published: April 2017

User experience and usability (UX) form a key part of research and best practice for product and software development. In this paper, the topic is addressed from the perspective of the Digital Humanities (DH) and approaches undertaken in two DH infrastructure projects, DARIAH and CENDARI are presented. Both projects addressed aspects of UX, focusing on the usage of a single software tool, as well as on an integrated research workflow using several tools and devices. The article lists the main factors, gleaned from research undertaken in the projects, that influence usability practices in the DH, and provides possible recommendations on how to approach them.
Energy Consumption and Process Efficiency as Affected by Extrusion-Cooking Conditions and Recipe Formulation During the Production of Gluten-Free Rice-Legumes Products
Authors: Bouasla Abdallah , Wójtowicz Agnieszka , Juśko Stanisław , Zidoune Mohammed Nasreddine
Published: April 2017

The objective of the study was to determine the effect of extrusioncooking conditions (moisture content and screw speed) and recipe formulation on process efficiency and energy consumption during the extrusion-cooking of gluten-free rice-legumes products, shaped for spaghetti-type pasta. Process efficiency (Q) was determined through measurement of the pasta weight and energy consumption was determined using specific mechanical energy consumption (SME). According to the obtained results, screw speed had a great significant impact on Q and SME values which increased as screw speed increased. Moisture content of raw materials had also a significant effect on Q and SME mainly at low screw speed applied. The process efficiency increased with the increase of raw materials moisture content while reverse observations were noted for the energy consumption. On the contrary, variations of recipe formulations did not affect the measured parameters.
Structure of a Flax Threshing Mass Device
Authors: Kamiński Edmund , Kocuba Victor Iofimovich , Kuboń Maciej , Sharshunov Vjacheslav
Published: April 2017

The object of the research consisted of a roller threshing unit with a profile elastic working surface of a parabolic type and a triangle one with rollers which turn concurrently with various angular speeds. Two rollers with 150 and 300 mm were investigated. The process of seeds separation from the threshing mass took place at its moisture of 10 to 35%. The relation of mixtures in the straw mass in a mass relation was changing within 10 to 35% with the length of stalks from 20 to 400 mm. The amount of the material provided for threshing was varied from 0.27 to 0.52 kg∙s-1∙m-1 and the slot between the rollers from 1.0 to 6.0 mm. The width of the base of notches located on the working surface of drums was within 25 to 150 mm, the height of notches on rollers was within 10 to 60 mm. Kinematic conditions of rollers operation were within 1.0 to 1.5. As a result of the research it was determined that a parabola is the optimal form of the profiled surface of rollers in a cross section. It ensures more effective seeds separation than a triangle configuration of drums. This conclusion is also confirmed by a theoretical discussion and is explained with the fact that the parabolic form of notches has a bigger surface than the triangle one and that they affect more seed-bags which leads to the increase of the seeds separation degree. The laboratory research allowed determination of rational ranges of parameters changes during flax mass threshing.
Empirical Analysis of the Financial Behavior of Investors with Brand Approach (Case Study: Tehran Stock Exchange)
Authors: Asgarnezhad Nouri Bagher , Motamedi Samira , Soltani Milad
Published: April 2017

Behavioral science in the field of finance and investment is among new topics raised in recent years. The relationship between financial sciences and other fields of social sciences such as financial psychology has caused researchers to do many researches regarding the behavior of investors in the financial markets and their reactions to different situations. Based on the theories of financial behavior, shareholders’ decision to buy and sell stocks is under the influence of internal and external psychological factors. Through designing and experimental testing of the model of investors’ financial behavior in the Tehran Stock Exchange with an emphasis on brand, this study was an attempt to investigate the influence of these factors. To this end, financial, psychological and social factors were considered as the most important external factors influencing the behavior of investors and, considering the mediating role of brand awareness, their impact on perceived risk and perceived return as well as investment intention was tested. The research population consisted of all individual investors in the Tehran Stock Exchange. In order to determine the sample size, considering unlimited population, Cochran formula was used and hence the sample size was determined to be 145. For data collection, standard questionnaire was used. Confirmatory factor analysis was used to test the reliability of the questionnaire and the research hypotheses were tested using path analysis. The results showed that psychological factors have a positive impact on perceived risk and returns. Financial factors had a positive impact on perceived risk but no impact on perceived return. The impact of social factors on perceived risk and perceived return was not confirmed. Moreover, the results showed that brand awareness has a moderating role in the relationship between social factors and perceived risk and return. However, its moderating role was not confirmed in the relationship between the psychological and financial factors and perceived risk and return. Perceived risk had a positive effect on attitude toward the brand. However, the impact of perceived return on attitude toward the brand was not significant. Finally, the attitude toward the brand had a positive effect on shareholders’ investment intention.
Entropy Generation on MHD Flow of Powell-Eyring Fluid Between Radially Stretching Rotating Disk with Diffusion-Thermo and Thermo-Diffusion Effects
Authors: Khan Najeeb Alam , Aziz Shahnila , Ullah Saif
Published: April 2017

An investigation is performed for an alyzing the effect of entropy generation on the steady, laminar, axisymmetric flow of an incompressible Powell-Eyring fluid. The flow is considered in the presence of vertically applied magnetic field between radially stretching rotating disks. The Energy and concentration equation is taking into account to investigate the heat dissipation, Soret, Dufour and Joule heating effects. To describe the considered flow non-dimensionalized equations, an exact similarity function is used to reduce a set of the partial differential equation into a system of non-linear coupled ordinary differential equation with the associated boundary conditions. Using homotopy analysis method (HAM), an analytic solution for velocity, temperature and concentration profiles are obtained over the entire range of the imperative parameters. The velocity components, concentration and temperature field are used to determine the entropy generation. Plots illustrate important results on the effect of physical flow parameters. Results obtained by means of HAM are then compared with the results obtained by using optimized homotopy analysis method (OHAM). They are in very good agreement.
Discussion on Flow-Through Phenomena in the Air Gauge Cascade
Authors: Jermak Czesław Janusz
Published: April 2017

In the paper, the flow-through phenomena in the air gauge are under discussion form the thermodynamic and gasodynamic perspective. The main elements of the cascade are considered the inlet nozzle (restriction), measuring chamber and the measuring nozzle with the measuring slot (displacement between the nozzle head and measured surface). The purpose of the analysis was to point out the impact on the metrological characteristics of the air gauge. In particular, attention was paid to the airflow through the measuring slot. Here, the complex phenomena take place, among others the supersonic areas and a “bubble ring,” which cause discontinuity and hysteresis in the static characteristic. On the other hand, the air stream expansion after the restriction (inlet nozzle) is observed in the measuring chamber. The point of the above discussion was to work out some recommendation on the nozzles geometry and the localization of the back-pressure measuring point in the chamber.
Verification of Ram-Press Pipe Bending Process using Elasto-Plastic FEM Model
Authors: Sidun Paweł , Łukaszewicz Andrzej
Published: April 2017

In this paper selected aspects of numerical modelling of bending pipes process are described. Elasto-plastic material model was used in COMSOL FEM environment. The results of numerical analyses of two kinds of steel were presented. The correctness of the proposed model was verified based on comparison shapes of deformed pipe profile obtained at the ending step of bending both from numerical simulations and experiment.
Tribological Properties and Microstructure of the Metal-Polymer Composite thin Layer Deposited on a Copper Plate by Electrocontact Sintering
Authors: Kovtun V. , Pasovets V. , Pieczonka T.
Published: April 2017

The properties of the electrocontact sintered metal-polymer composite materials are strongly determined by the heat flow taking place during sintering, which, in turn, is influenced by the amount and initial distribution of the polymer particles in the metal matrix. In case of the metal-polymer powder mixture in the form of a thin layer deposited on the bulk metal substrate, the influence of the latter is also taken into consideration. Thus, the model simulating the heating and sintering of the thin layer made of metal-polymer powder mixture on a metal plate is proposed. Based on mathematical calculations relating to the model describing the thermal state of the system, it is shown how heat flow fields are formed within the layer, depending on the polymer content and its distribution. These theoretical simulations seem to be useful in optimising the production of the antifriction metal-polymer layer on a bulk copper substrate by electrocontact sintering. The results of the tribological experiments and microstructural observations are in a good agreement with the theoretical model.
Theoretical-Experimental Analysis of the Workability of the Ni50Cr45N0.6 alloy
Authors: Łukaszek-Sołek A. , Świątoniowski A. , Celadyn K. , Sińczak J.
Published: April 2017

In this paper, the results of investigations into, and of the analyses of, the hot deformation behaviour of the Ni50Cr45N0.6 alloy were presented. Compression tests were conducted on a Gleeble 3800 thermo-mechanical simulator within the following temperatures range 850-1200°C and within that of the strain rate 1-40 s-1 to the constant true strain of 0.9, for the purpose of fulfilling the objective of obtaining experimental stress date. Those data were taken advantage of for the purpose of calculating the workability parameters, and that means the efficiency of power dissipation η, the flow instability ξ and the strain rate sensitivity m. The processing maps based upon Murty’s criterion were drawn up for the following true strain range: 0.2-0.9, and, subsequently, both processing windows and the flow instability areas were determined. For the alloy being analysed, the most advantageous conditions of metal forming were ascertained within the following range of temperatures: 950-1000°C, and for that of the strain rate amounting to 10-40 s-1, and that because of (occurring at the temperature of 950°C) the peak of the efficiency of power dissipation parameter η, amounting to 22% (in accordance with Murty’s criterion). The flow instability areas identified on the processing maps ought to be avoided in metal forming processes. Experimental rolling tests were also conducted.
Optimisation of Mechanical Properties of 18%Ni350 Grade Maraging Steel Using Novel Heat Treatment
Authors: Marcisz J. , Adamczyk M. , Garbarz B.
Published: April 2017

The paper presents results of examinations of properties and microstructure of maraging steel grade MS350 (18Ni350) produced by a novel heat treatment method called „short-time ageing“. It has been found that maraging steel after application of the short-time ageing achieves unique properties, in particular good combination of strength and impact toughness. After short-time ageing for time of heating up to 600 seconds at temperature of 550°C hardness in the range from 48 to 56 HRC, tensile strength ranging from 2000 to 2250 MPa, yield strength from 1930 to 2170 MPa and total elongation in the range 7-8% as well as notch impact toughness of 20 J/cm2 at temperature minus 40°C were obtained. Results of microstructure examination in transmission electron microscope (TEM) with application of high resolution technique (HRTEM) have shown presence of Ni3Mo nano-precipitates of orthorhombic crystallographic structure. Precipitates were characterized by rod-like shape and were homogenously distributed in martensitic matrix of steel with high density of dislocations. The average size of cross-section of precipitates was ca. 4 nm while length reached several dozen of nm.
FEM Analysis of Loads and Torque in a Skew Rolling Process for Producing Axisymmetric Parts
Authors: Pater Z.
Published: April 2017

Skew rolling is a metal forming technique which can be used for producing stepped axles and shafts. This paper investigates seventeen cases of rolling at varying process parameters by the finite element method. As a result, it is possible to determine the effect of the forming angle α, skew angle Θ, linear velocity of the chuck, v, billet temperature, T, rotational speed of the rolls, n, reduction ratio, δ and friction factor, m, on axial load (acting on the chuck), radial load (acting on the roll in the radial direction) and torque. The results will be used when designing a laboratory stand for skew rolling which will be constructed at the Lublin University of Technology.
Shielding gas effect on the structure of variable polarity GMA weldbrazed joints of galvanised sheets
Authors: Pfeifer T. , Winiowski A. , Pikuła J.
Published: April 2017

The article presents the course and results of tests aimed to determine the effect of shielding gas on the shape of a weldbraze and on the structure of weldbrazed joints made of thin galvanised sheets. Test joints were made using innovative VP GMA weldbrazing utilising variable current and voltage waveforms. The tests involved the use of 3 types of shielding gases and mixtures, i.e. Ar, Ar + 1% O2 and Ar + 18% CO2, and required macro and microscopic metallographic examination of overlay brazes and weldbrazed joints. The tests conducted have revealed that the use of mixtures containing active gases, and CO2 in particular, increases the heat input of a weldbrazing process, improves the wettability of sheets and the geometry of weldbrazes, yet it also favours greater coat damage in the joining area and causes partial melting of workpieces.
Mechanical properties of Ni-Fe-Cu-P-B alloy produced by two component melt spinning (TCMS)
Authors: Wojciechowska M. , Ziewiec K. , Kąc S. , Prusik K.
Published: April 2017

The aim of this work was to investigate the microstructure and mechanical properties of the two-component melt-spun (TCMS) alloy produced from Ni40Fe40B20 and Ni70Cu10P20 melts. The Ni40Fe40B20, Ni70Cu10P20, Ni55Fe20Cu5P10B10 alloys were arc-melted. Then the alloys were melt-spun in the two different ways i.e.: by casting from a single-chamber crucible and from the two-chamber crucible. All of the above mentioned alloys were processed in the first way and the Ni40Fe40B20 and Ni70Cu10P20 were simultaneously cast on the copper roller from the two-chamber crucible. The microstructure of the alloy was studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) and light microscopy. The mechanical properties were investigated using tensile testing and nanoindentation. The two-component melt-spun (TCMS) amorphous Ni55Fe20Cu5P10B10 alloy present hardness, tensile strength and Young modulus on the significantly higher level than for a single phase amorphous Ni55Fe20Cu5P10B10 alloy and slightly below the corresponding values for the Ni40Fe40B20.
Numerical investigation of heat exchange in rotary furnace
Authors: Kolczyk E. , Miczkowski Z. , Czernecki J.
Published: April 2017

Process of heat exchange in a rotary furnace during converter slag reduction was modelled.Temperature distribution in the furnace and temperature of the charge (slag) only were examined. Influence of modification of the process gas supply method by changing the number of nozzles on the course of the reduction process was analyzed. It has been found out that application of a nozzle as a submerged flame burner provides possibilities to reach higher charge temperature. Application of more nozzles in the process of converter slag reduction can increase temperature of reduced slag and provide better uniformity of charge heating.
The Effect of Water Mist Cooling of Casting Die on the Solidification, Microstructure and Properties of AlSi20 Alloy
Authors: Władysiak R. , Kozuń A. , Pacyniak T.
Published: April 2017

Unmodified AlSi20 alloy were casted at the research station, allowing for sequential multipoint cooling using a dedicated computer- controlled program. This method allows for the formation of the microstructure of hypereutectic AlSi20 alloy and also increases hardness. Primary silicon dendrites were found in the microstructure of cooled samples. Based on these dendrites, the formation of primary silicon particles is explained. Cooling of casting die with a water mist stream causes changes in solidification, which leads to expansion of the boundary layer with columnar crystals and shrinkage of the core zone with equiaxed crystals. It also causes more regular hardness distribution around pre-eutectic Si crystals, which can lead to tensile strength and machinability improvement.
Interaction mechanism of non-metallic particles with crystallization front
Authors: Żak P. L. , Kalisz D. , Rączkowski G.
Published: April 2017

The process of steel solidification in the CCS mould is accompanied by a number of phenomena relating to the formation of non-metallic phase, as well as the mechanism of its interaction with the existing precipitations and the advancing crystallization front. In the solidification process the non-metallic inclusions may be absorbed or repelled by the moving front. As a result a specific distribution of non-metallic inclusions is obtained in the solidified ingot, and their distribution is a consequence of these processes. The interaction of a non-metallic inclusion with the solidification front was analyzed for alumina, for different values of the particle radius. The simulation was performed with the use of own computer program. Each time a balance of forces acting on a particle in its specific position was calculated. On this basis the change of position of alumina particle in relation to the front was defined for a specific radius and original location of the particle with respect to the front.
Formation of microstructure and properties of Cu-3Ti alloy in thermal and thermomechanical processes
Authors: Szkliniarz A.
Published: April 2017

This paper presents the possibilities of forming the microstructure as well as mechanical properties and electrical conductivity of Cu-3Ti alloy (wt.%) in thermal and thermomechanical processes that are a combination of homogenising treatment, hot and cold working, solution treatment and ageing. Phase composition of the alloy following various stages of processing it into the specified semi-finished product was being determined too. It was demonstrated that the application of cold plastic deformation between solution treatment and ageing could significantly enhance the effect of hardening of the Cu-3Ti alloy without deteriorating its electrical conductivity. It was found that for the investigated alloy the selection of appropriate conditions for homogenising treatment, hot and cold deformation as well as solution treatment and ageing enables to obtain the properties comparable to those of beryllium bronzes.
Kinetics of pearlite spheroidization
Authors: Matusiewicz P. , Augustyn-Nadzieja J. , Czarski A. , Skowronek T.
Published: April 2017

The pearlite spheroidization in Fe-0.76%C high purity steel was investigated. The samples of a coarse pearlite microstructure were isothermal annealed at 700, 680, 660, 640 and 620°C for various times, up to 800 hours. For quantitative description of the spheroidization process stereological parameter, SV (ferrite/cementite interface surface density) was used. The activation energy 104.8±11.4 kJ/mol was found for the spheroidization process. This value shows good agreement with the activation energy for iron and carbon diffusion along a ferrite/cementite interface, so the coupled interface diffusion is the rule-controlling process.
The fixed-effects analysis of the relation between SDAS and carbides for the airfoil blade traces
Authors: Pietraszek J. , Szczotok A. , Radek N.
Published: April 2017

The primary objective was to test a usefulness of the specific fixed-effect model for the analysis of quantitative relationships gathered from the image analysis of the material microstructures. The dataset was obtained from the investigation of turbine blades made from superalloy IN713C. The analysis based on the general linear model resulted in informative plots revealing mutual relationships between secondary dendrite arm spacing and the mean plane section area of carbides in the material. Directions for further research also were obtained.
Evaluation of Carbides in Turbine Blade Made of IN713C Superalloy After Hot Isostatic Pressing
Authors: Kościelniak B. , Roskosz S. , Cwajna J.
Published: April 2017

The IN713C is nickel-based superalloy, used to produce low pressure turbine blades in a process of investment casting. However, porosity which is formed during the casting, decreases mechanical properties of IN713C. Therefore, to eliminate porosity, a process of hot isostatic pressing was applied. Nonetheless, HIP also least to some changes in the microstructure of tested material. The main aim of this paper is to characterize the morphology of carbides before and after hot isostatic pressing. Microstructural characterization was carried out with the use of a scanning electron microscope equipped with an energy dispersive X-ray spectrometer and an electron backscatter diffraction detector. The size and shape of carbides were evaluated by quantitative metallography methods methods. The results show that the amount, size and heterogeneity of arrangement of the carbides increased after application of HIP treatment.
Forecasting the distribution of precipitate diameters in the presence of changes in the structure of the material
Authors: Zieliński A. , Miczka M. , Golański G.
Published: April 2017

The results of investigations on the microstructure of T23 and T24 low-alloy steels as well as P91 and P92 high-chromium steels in the as-received condition and after 70.000 h annealing at 550-650°C are presented. The quantitative analysis of the existing precipitates was performed for representative images of microstructure. The statistical analysis of collected data allowed the parameters of a selected theoretical statistical distribution to be estimated. A forecast of average precipitate diameter and standard deviation of such a distribution for the time of 100,000 hours at 550 and 600°C for T23 and T24 steels and at 600 and 650°C for P91 and P92 steels was calculated. The obtained results of investigations have made it possible to compare changes in the microstructure of various steel grades due to long-term impact of elevated temperature. They have also confirmed the possibility of using, in evaluating the degradation degree of materials in use, the forecasting methods that derive from mathematical statistics, in particular the theory of stochastic processes and forecast by analogy methods. The presented approach allows the development of a forecast of precipitate diameter probability density under the microstructure instability conditions for selected steel grades. The assessment of material condition that takes into consideration, but is not limited to, the precipitate diameter measurement is useful as an assessment component in estimating the time of safe service of power unit elements working under creep conditions.
Copper droplets agglomeration/coagulation in the conditions similar to industrial ones
Authors: Wołczyński W. , Sypien A. , Tarasek A. , Bydałek A. W.
Published: April 2017

The studied copper droplets suspension in the liquid slag came from the direct-to-blister technology developed in the KGHM - Polska Miedź S.A. plants. A treatment by the stimulators and reagents was performed in the conditions delivered / ensured by the BOLMET S.A., Wiechlice. These conditions were similar to those usually applied to the industrial process. Particularly, this treatment was similar, to some extent, to that known for the electric arc-furnace technology employed in the Smelter and Refinery Plant, Głogów. An effectiveness of the newly developed and patented complex chemical/reagent for the copper removal from slag was tested during the treatment. The effect of the liquid slag stirring on the copper droplets self-cleaning was also analysed. The performed test confirmed the effectiveness of the studied complex reagent in agglomeration, coagulation and sedimentation of the copper droplets.
Determination of pearlite morphology in high-carbon hot rolled steel
Authors: Szala J. , Kuc D.
Published: April 2017

The article presents the results of tests of influence of the thermo-mechanical treatment parameters on the mechanical properties and microstructure of steel C70D for wire rod. The methodology of quantitative description of pearlite morphology in steels with the use of the method on which a new computer program “PILS” - Pearlite Inter-Lamellar Spacing is based was presented. In order to verify the method, some quantitative tests of microstructure in samples after physical simulation of heat-plastic treatment were conducted on a deformation dilatometer device with diverse cooling rate for steel C70D. The process of rolling was conducted in simulation in continuous finishing train arrangement. Elaborated program and conducted tests will be used during preparations of modified technologies of wire rod rolling to prepare products made of steel, the microstructure of which is characterised with smaller interlamellar spacing.
Induction hardening of tool steel for heavily loaded aircraft engine components
Authors: Rokicki P.
Published: April 2017

Induction hardening is an innovative process allowing modification of the materials surface with more effective, cheaper and more reproducible way to compare with conventional hardening methods used in the aerospace industry. Unfortunately, high requirements and strict regulation concerning this branch of the industry force deep research allowing to obtain results that would be used for numerical modelling of the process. Only by this way one is able to start the industrial application of the process. The main scope of presented paper are results concerning investigation of microstructure evolution of tool steel after single-frequency induction hardening process. The specimens that aim in representing final industrial products (as heavily loaded gears), were heat- -treated with induction method and subjected to metallographic preparation, after which complex microstructure investigation was performed. The results obtained within the research will be a basis for numerical modelling of the process of induction hardening with potential to be introduced for the aviation industrial components.
Welding thermal cycle-triggered precipitation processes in steel S700MC subjected to the thermo-mechanical control processing
Authors: Górka J.
Published: April 2017

This study presents tests concerned with welding thermal process-induced precipitation processes taking place in 10 mm thick steel S700MC subjected to the Thermo-Mechanical Control Process (TMCP) with accelerated cooling. The thermomechanical processing of steel S700MC leads to its refinement, structural defects and solutioning with hardening constituents. Tests of thin foils performed using a transmission electron microscope revealed that the hardening of steel S700MC was primarily caused by dispersive (Ti,Nb)(C,N) precipitates (being between several and less than twenty nanometers in size). In arc welding, depending on a welding method and linear energy, an increase in the base material in the weld is accompanied by the increased concentration of hardening microagents in the weld. The longer the time when the base material remains in the liquid state, the greater the amount of microagents dissolved in the matrix. During cooling, such microagents can precipitate again or remain in the solution. An increase in welding linear energy is accompanied by an increase in the content of hardening phases dissolved in the matrix and, during cooling, by their another uncontrolled precipitation in the form of numerous fine-dispersive (Ti,Nb)(C,N) precipitates of several nm in size, leading to a dislocation density increase triggered by type 2 internal stresses.
The influence of manual metal arc multiple repair welding of long operated waterwall on the structure and hardness of the heat affected zone of welded joints
Authors: Pikuła J. , Łomozik M. , Pfeifer T.
Published: April 2017

Welded installations failures of power plants, which are often result from a high degree of wear, requires suitable repairs. In the case of cracks formed in the weld bead of waterwall, weld bead is removed and new welded joint is prepared. However, it is associated with consecutive thermal cycles, which affect properties of heat affected zone of welded joint. This study presents the influence of multiple manual metal arc welding associated with repair activities of long operated waterwall of boiler steel on properties of repair welded joints. The work contains the results of macro and microscopic metallographic examination as well as the results of hardness measurements.
Development of hot tearing evaluation method for Al-based alloys
Authors: Brůna M.
Published: April 2017

This paper focuses on developing an advanced test method and its use to study hot tearing defects in aluminium alloy castings. The paper consists of two parts. The first part introduces the reader to hot tearing in general, and provides theoretical analysis of the hot tearing phenomenon. The second part describes a newly developed method for assessing hot tearing susceptibility, and also gives the results on hot tearing for various aluminium alloys. During the test, the effect of alloy chemical composition on hot tearing susceptibility was analyzed. Three different Al-based alloys with varying Si, Cu and Ti contents were examined. Conclusions deal with the effect of individual elements on hot tearing susceptibility, and confirm that the main objective was achieved and the proposed method proves to be repeatable and reliable.
Influence of the reclamation method of spent moulding sands on the possibility of creating favourable conditions for gases flow in a mould
Authors: Łucarz M. , Drożyński D.
Published: April 2017

The results of investigations concerning the influence of the applied sand matrix (fresh sand, reclaim) on the properties of moulding sands used for production of large dimensional castings (ingot moulds, ladles), are presented in the hereby paper. The performed investigations were aimed at determining the influence of various reclamation methods of spent moulding sands on the quality of the obtained reclaimed material. Moulding sands were prepared on the fresh quartz matrix as well as on sand matrices obtained after various reclamation methods. The selected moulding sand parameters were tested (strength, permeability, grindability, ignition losses, pH reactions). It can be stated, on the basis of the performed investigations, that the kind of the applied moulding sand matrix is of an essential meaning from the point of view of creating conditions minimising formation of large amounts of gases and their directional migration in a casting mould.
Solid-liquid interface morphology of white carbide eutectic during directional solidification
Authors: Trepczyńska-Łent M.
Published: April 2017

In this paper the analysis of solid-liquid interface morphology in white carbide eutectic was made. In a vacuum Bridgman-type furnace, under an argon atmosphere, directionally solidified sample of Fe - C alloy was produced. The pulling rate was v = 125 μm/s (450 mm/h) and constant temperature gradient G = 33.5 K/mm. The microstructure of the sample was frozen. The microstructure of the sample was examined on the longitudinal section using an light microscope and scanning electron microscope.
Effect of parameters of high-pressure die casting on occurrence of casting nonconformities in sleeves of silumin alloy EN AB 47100
Authors: Pałyga Ł. , Stachowicz M. , Granat K.
Published: April 2017

The paper presents a research on the effect of extreme - for the technology of the considered silumin EN AB 47100 - parameters of high-pressure die casting on occurrence of casting nonconformities. Considered was influence of the way of assembling the mould cooled-down to 140-160°C, non-standard for the selected casting, and pouring temperature in the range of 705 to 720°C (higher than the recommended) of non-refined alloy. The castings were prepared with use of a high-pressure casting machine made by Kirov with mould closing force of 2500 kN. Occurrence of nonconformities was evaluated on properly prepared specimens taken from the castings manufactured with various parameters of the injection piston and various multiplication pressures. The results were subjected to quantitative and qualitative analyses of casting nonconformities and distribution of major alloying elements. It was found that proper selection of working parameters of the casting machine, in spite of disadvantageous pouring conditions, makes it possible to reduce occurrence of some casting defects, like shrinkage cavities and porosity, to improve tightness of castings even when the alloy refining process is omitted.
Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods
Authors: Stachowicz M. , Granat K. , Pałyga Ł.
Published: April 2017

The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.
Shaping optimal zinc coating on the surface of high-quality ductile iron casting. Part I – Moulding technologies vs. zinc coating
Authors: Szczęsny A. , Kopyciński D. , Guzik E.
Published: April 2017

Studies have demonstrated that in the process of hot dip galvanizing the decisive influence on the mechanism of zinc coating formation and properties has the quality of the mechanically untreated (raw) surface layer of the galvanized product. The terms “casting surface layer” denote various parameters of the microstructure, including the type of metal matrix, the number of grains and the size of graphite nodules, possible presence of hard spots (the precipitates of eutectic cementite) and parameters of the surface condition. The completed research has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing.
Optimization of a thin-walled element geometry using a system integrating neural networks and finite element method
Authors: Golewski P. , Gajewski J. , Sadowski T.
Published: April 2017

Artificial neural networks [ANNs] are an effective method for predicting and classifying variables. This article presents the application of an integrated system based on artificial neural networks and calculations by the finite element method [FEM] for the optimization of geometry of a thin-walled element of an air structure. To ensure optimal structure, the structure’s geometry was modified by creating side holes and ribs, also with holes. The main criterion of optimization was to reduce the structure’s weight at the lowest possible deformation of the tested object. The numerical tests concerned a fragment of an elevator used in the “Bryza” aircraft. The tests were conducted for networks with radial basis functions [RBF] and multilayer perceptrons [MLP]. The calculations described in the paper are an attempt at testing the FEM - ANN system with respect to design optimization.
Selection of basic position in Refill Friction Stir Spot Welding of 2024-T3 and D16UTW aluminum alloy sheets
Authors: Lacki P. , Derlatka A. , Gałaczyński T.
Published: April 2017

One of the important parameters of Refill Friction Stir Spot Welding is the so-called basic position of the tool. This is the arrangement of the pin and sleeve which occurs when the tool is plunged into the material. The basic positions can be divided into two categories. In the first category, the sleeve and the pin are above the sheet surface or below sheet surface and in the second category the pin is retracted within the sleeve or protrudes from it.

The aim of the work was to test four settings of the basic position, and then determine the best setting of the basic position, without changing the other welding parameters. Joints made of an aluminum alloy 2024-T3 sheet having a thickness of 1.0 mm and an aluminum alloy D16UTW sheet having a thickness of 0.6 mm were analysed. The best setting of the basic position was determined based on assessment of the force carried in shear test, macrostructure and weld face of the joints.
On certain differential sandwich theorems involving a generalized Sǎlǎgean operator and Ruscheweyh operator
Authors: Loriana Andrei
Published: April 2017

In the present paper we introduce sufficient conditions for subordination and superordination involving the operator

DR
λ

m
,
n

$DR_\lambda ^{m,n} $

and also we obtain sandwich-type results.
Generalized almost paracontact structures
Authors: Blaga Adara M. , Ida Cristian
Published: April 2017

The notion of generalized almost paracontact structure on the generalized tangent bundle TM ⊕ T* M is introduced and its properties are investigated. The case when the manifold M carries an almost paracontact metric structure is also discussed. Conditions for its transformed under a β- or a B-field transformation to be also a generalized almost paracontact structure are given. Finally, the normality of a generalized almost paracontact structure is defined and a characterization of a normal generalized almost paracontact structure induced by an almost paracontact one is given.
Two-channel sampling in wavelet subspaces
Authors: Kim J.M. , Kwon K.H.
Published: April 2017

We develop two-channel sampling theory in the wavelet subspace V
1 from the multi resolution analysis {Vj
}
j

∈𝕫. Extending earlier results by G. G. Walter [11], W. Chen and S. Itoh [2] and Y. M. Hong et al [5] on the sampling theory in the wavelet or shift invariant spaces, we find a necessary and sufficient condition for two-channel sampling expansion formula to hold in V
1.
Effect of the initial stress and rotation on free vibrations in transversely isotropic human long dry bone
Authors: Mahmoud S. R. , Marin M. , Al-Basyouni K.S.
Published: April 2017

The object of the present paper is to study the influence of the initial stress and rotation on wave propagation of harmonic waves in a human long dry bone as transversely isotropic material, subject to the boundary conditions that the outer and inner surfaces are traction free. The equations of elastodynamic are solved in terms of displacements. The natural frequency of the plane vibrations in the case of harmonic vibrations has been obtained. The frequencies and the phase velocity are calculated numerically, the effects of the initial stress and rotation are discussed. Comparisons are made with the result in the absence of rotation and initial stress.
On neighborhoods of functions associated with conic domains
Authors: Yağmur Nihat
Published: April 2017

Let k − ST [A, B], k ≥ 0, −1 ≤ B < A ≤ 1 be the class of normalized analytic functions defined in the open unit disk satisfying

ℜ

(

(
B
−
1
)

z

f
′

(
z
)

f
(
z
)

−
(
A
−
1
)

(
B
+
1
)

z

f
′

(
z
)

f
(
z
)

−
(
A
+
1
)

)

>
k

|

(
B
−
1
)

z

f
′

(
z
)

f
(
z
)

−
(
A
−
1
)

(
B
+
1
)

z

f
′

(
z
)

f
(
z
)

−
(
A
+
1
)

−
1

|

.

$$\Re \left( {{{(B - 1){{zf'(z)} \over {f(z)}} - (A - 1)} \over {(B + 1){{zf'(z)} \over {f(z)}} - (A + 1)}}} \right) > k\left| {{{(B - 1){{zf'(z)} \over {f(z)}} - (A - 1)} \over {(B + 1){{zf'(z)} \over {f(z)}} - (A + 1)}} - 1} \right|.$$

and let k − UCV [A, B], k ≥ 0, −1 ≤ B < A ≤ 1 be the corresponding class satisfying

ℜ

(

(
B
−
1
)

(

z

f
′

(
z
)

)

′

f
′

(
z
)

−
(
A
−
1
)

(
B
+
1
)

(

z

f
′

(
z
)

)

′

f
′

(
z
)

−
(
A
+
1
)

)

>
k

|

(
B
−
1
)

(

z

f
′

(
z
)

)

′

f
′

(
z
)

−
(
A
−
1
)

(
B
+
1
)

(

z

f
′

(
z
)

)

′

f
′

(
z
)

−
(
A
+
1
)

−
1

|

.

$$\Re \left( {{{(B - 1){{\left( {zf'(z)} \right)^{\prime } } \over {f'(z)}} - (A - 1)} \over {(B + 1){{\left( {zf'(z)} \right)^{\prime } } \over {f'(z)}} - (A + 1)}}} \right) > k\left| {{{(B - 1){{\left( {zf'(z)} \right)^{\prime } } \over {f'(z)}} - (A - 1)} \over {(B + 1){{\left( {zf'(z)} \right)^{\prime } } \over {f'(z)}} - (A + 1)}} - 1} \right|.$$

For an appropriate δ > 0, the δ neighborhood of a function f ∈ k − UCV [A, B] is shown to consist of functions in the class k − ST [A, B].