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Abstract

The objective of the paper is to evaluate the implications of trade liberalization under the Transatlantic Trade and Investment Partnership (TTIP) for the Polish economy. We analyze the level of tariffs and non-tariff protection in the US and in the EU and identify products particularly “sensitive” from the point of view of TTIP liberalization. With the help of a partial equilibrium model, we simulate the trade implications of the TTIP for Poland’s trade with the US at the detailed product level. We analyze trade creation and diversion effects of tariff elimination and partial removal of non-tariff barriers. We found that the TTIP can increase Poland’s trade with the US by around 45 percent with a limited impact on its trade with the European Union (EU) members. Subsequent general equilibrium simulations show that trade diversion effects of the TTIP are substantial, while the welfare benefits of the agreement are limited.
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Authors and Affiliations

Jan Hagemejer
1 2
ORCID: ORCID
Jan Jakub Michałek
1
ORCID: ORCID
Karolina Pawlak
3
ORCID: ORCID

  1. University of Warsaw, Poland
  2. CASE Center for Economic and Social Research, Warsaw, Poland
  3. Poznan University of Life Sciences, Poland
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Abstract

In this paper, we propose a robust estimation of the conditional variance of the GARCH(1,1) model with respect to the non-negativity constraint against parameter sign. Conditions of second order stationary as well as the existence of moments are given for the new relaxed GARCH(1,1) model whose conditional variance is estimated deriving firstly the unconstrained estimation of the conditional variance from the GARCH(1,1) state space model, then, the robustification is implemented by the Kalman filter outcomes via density function truncation method. The GARCH(1,1) parameters are subsequently estimated by the quasi-maximum likelihood, using the simultaneous perturbation stochastic approximation, based, first, on the Gaussian distribution and, second, on the Student-t distribution. The proposed approach seems to be efficient in improving the accuracy of the quasi-maximum likelihood estimation of GARCH model parameters, in particular, with a prior boundedness information on volatility.
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Authors and Affiliations

Abdeljalil Settar
1
ORCID: ORCID
Nadia Idrissi Fatmi
1
ORCID: ORCID
Mohammed Badaoui
1 2
ORCID: ORCID

  1. LIPIM, École Nationale des Sciences Appliquées (ENSA), Khouribga, Morocco
  2. LaMSD, École Supérieure de Technologie (EST), Oujda, Morocco
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Abstract

The educational expansion in many advanced economies in the past few decades has triggered a debate on overeducation. The aim of the study is to provide an empirical evaluation of the wage effects of overeducation in different occupational groups. We also analyse whether these effects differ between genders. In order to achieve this, we use individual data from the Structure of Wages and Salaries by Occupations database of firms with 10 or more employees in Poland. We use data from the 2006-2014 waves of the survey. We calculate the impact of overeducation on wages using a Mincer-type wage regression model. We show that on average workers are rewarded for being overeducated, but the size of wage effects of overeducation differs among particular occupational groups. We show also that the choice of the method of measurement of overeducation affects the results.
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Authors and Affiliations

Paulina Broniatowska
1
ORCID: ORCID

  1. University of Warsaw
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Abstract

There are reasons researchers may be interested in accounting for spatial heterogeneity of preferences, including avoiding model misspecification and the resulting bias, and deriving spatial maps of willingness-to-pay (WTP), which are relevant for policy-making and environmental management. We employ a Monte Carlo simulation of three econometric approaches to account for spatial preference heterogeneity in discrete choice models. The first is based on the analysis of individual-specific estimates of the mixed logit model. The second extends this model to explicitly account for spatial autocorrelation of random parameters, instead of simply conditioning individual-specific estimates on population-level distributions and individuals’ choices. The third is the geographically weighted multinomial logit model, which incorporates spatial dimensions using geographical weights to estimate location-specific choice models. We analyze the performance of these methods in recovering population-, region- and individual-level preference parameter estimates and implied WTP in the case of spatial preference heterogeneity. We find that, although ignoring spatial preference heterogeneity did not significantly bias population-level results of the simple mixed logit model, neither individual-specific estimates nor the geographically weighted multinomial logit model was able to reliably recover the true region- and individual-specific parameters. We show that the spatial mixed logit proposed in this study is promising and outline possibilities for future development.
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[23] McFadden D., (1974), Conditional Logit Analysis of Qualititative Choice Behaviour, [in]: Frontiers in Econometrics, [ed.:] Zarembka P., Academic Press, New York, NY, 105–142.
[24] Smith T. E., LeSage J. P., (2004), A bayesian probit model with spatial dependencies, Spatial and Spatiotemporal Econometrics 18(18), 127–160.
[25] Train K., Sonnier G., (2005), Mixed Logit with Bounded Distributions of Correlated Partworths, [in:] Applications of Simulation Methods in Environmental and Resource Economics, [eds.:] Scarpa R., Alberini A., Springer Netherlands, 117–134.
[26] Train K. E., (2009), Discrete Choice Methods with Simulation, 2 Ed., Cambridge University Press, New York.
[27] Yao R. T., Scarpa R., Turner J. A., Barnard T. D., Rose J. M., Palma J. H. N., Harrison D. R., (2014), Valuing biodiversity enhancement in New Zealand’s planted forests: Socioeconomic and spatial determinants of willingness-to-pay, Ecological Economics 98(0), 90–101.


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Authors and Affiliations

Wiktor Budziński
1
ORCID: ORCID
Mikołaj Czajkowski
1
ORCID: ORCID

  1. University of Warsaw
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Abstract

The olive psyllid Euphyllura straminea Loginova (Hemiptera: Aphalaridae) is one of the most important pests of olive trees in Iran. To determine this pest’s economic injury level (EIL) and to evaluate the relationship between density of nymphs (DON) and yield loss, different densities of olive psyllid nymphs were maintained on olive trees by different insecticide concentrations. Counting nymphs on olive terminal shoots was done to determine nymph abundance at the end of nymphal stage. Different densities of olive psyllid nymphs resulted in significantly different yield losses of olive trees. Regression analysis was used to determine the relationship between nymph density and yield loss. Considering pest management costs, the market value of olive, and insecticide efficiency, economic injury levels were evaluated from 4.08 to 7.14 nymphal days. The olive psyllid EIL values could be used to plan a pest control program in Zanjan and Guilan provinces.
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Authors and Affiliations

Aref Marouf
1
Mohammadreza Abbasi Mojdehi
2
Shamsollah Najafi
1

  1. Plant Protection Department, Agricultural and Natural Resources Research Center of Zanjan Province (AREEO), Iran
  2. Plant Protection Department, Agricultural and Natural Resources Research Center of Guilan Province, Rasht, Iran
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Abstract

The high sensitivity of beans to herbicides is one of the limiting factors regarding the management of dicot weeds in bean crops. Protoporphyrinogen oxidase (PPO) inhibition is an important mechanism of action that has unregistered molecules with potential use in bean crops. The objectives of this study were to investigate the tolerance of Brazilian bean cultivars to distinct PPO inhibitors and to determine the existence of cross-tolerance in cultivars to the different PPO inhibitor chemical groups. In the first and second experiments, the BRSMG Talismã, Jalo Precoce, BRS Esplendor, and IPR 81 cultivars were subjected to saflufenacil doses pre- (0, 9.6, 14.1, 20.5, 30.0, and 43.8 g a.i. ‧ ha–1) and post-emergence (0, 0.7, 1.0, 1.5, 2.1, and 3.1 g a.i. ‧ ha–1). In the third experiment, the tolerance of 28 bean genotypes to saflufenacil (20.5 g a.i. ‧ ha–1) in pre-emergence was determined. In the fourth, fifth, sixth and seventh experiments, we investigated the cross-tolerance of bean to the fomesafen, flumioxazin, sulfentrazone, and saflufenacil herbicides, respectively. Even very low saflufenacil doses in post-emergence caused plants of all cultivars to die rapidly; therefore, the tolerance was much lower at this application time than in pre-emergence. There was high tolerance variability to saflufenacil among the 28 cultivars. The bean tolerance to fomesafen, flumioxazin, sulfentrazone, and saflufenacil applied pre-emergence depended on the cultivar and dose. Fomesafen was highlighted owing to its higher selectivity in relation to the different cultivars. No cross-tolerance pattern to the PPO inhibitor chemical groups applied in pre-emergence was observed among the evaluated bean cultivars. The results of this study could be of significance to farmers and technical assistance personnel, as well as for future research on cultivar breeding and the elucidation of biochemical and genetic mechanisms involved in herbicide tolerance.
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Authors and Affiliations

Antonio Pedro Brusamarello
1
Michelangelo Muzell Trezzi
1
Fortunato de Bortoli Pagnoncelli Júnior
1
Paulo Henrique de Oliveira
1
Taciane Finatto
1
Marcos Vinícius Jaeger Barancelli
1
Bruno Alcides Hammes Schmalz
1
Patrícia Bortolanza Pereira
1

  1. Department of Agronomy, Federal Technological University of Paraná (UTFPR), Brazil
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Abstract

Extremely dense fog event was studied on the 3rd December 2001, which occurred in the city of Apatity, the Kola Peninsula, northwestern Russia. Fog had low visibility (30–50 m) and lasted 17 h. Variations of atmospheric pressure and electric field before and during the fog event were measured. Multiple Taper Method (MTM) of spectral analysis has revealed pulsations of the atmospheric electric field in the frequency band of 0.007–0.05 Hz with a power-law turbulence spectrum. MTM and wavelet decomposition analysis results indicate the appearance of two types of atmospheric pressure oscillations under the fog conditions: low-frequency variations with periods of internal gravity waves and a substantial increase in pulsation intensity (more than an order of magnitude) in the high frequency (0.03–0.35 Hz) range. These results may help to improve the understanding of the microphysics of fog formation, development, and dissipation. High-frequency pulsations generation of atmospheric pressure under the fog conditions is also of interest because their period is close to the range of infrasonic oscillations, which can have negative consequences for human health.
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Authors and Affiliations

Oleg I. Shumilov
1
Elena A. Kasatkina
1
Dmitry V. Makarov
1
Marek Krapiec
2

  1. Institute of North Industrial Ecology Problems, Kola Science Centre RAS, Fersman 14a, Apatity, Russia
  2. University of Science and Technology (AGH), Mickiewicza 30, 30-059 Krakow, Poland
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Abstract

The presented article concerns the issue of supporting the ADI cast iron product manufacturing process and presents an IT system dedicated mainly to designers and technologists. Designers can be supported at the stage of selecting types of materials and technologies (including ADI cast iron) to produce products with required properties. Technologists can obtain support in determining the parameters (temperature and chemical) of the ADI cast iron manufacturing process in order to obtain products with specific properties. The system also contains an information resources (standards, documentation, examples) concerning ADI cast iron and products made of it. Examples of use by individual system users are presented as a case study.
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Authors and Affiliations

A. Opaliński
1
ORCID: ORCID
D. Wilk-Kołodziejczyk
1 2
ORCID: ORCID

  1. AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Krakow, Poland
  2. Łukasiewicz Research Network – Krakow Institute of Technology, 73 Zakopiańska Str., 30-418 Kraków, Poland
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Abstract

The aim of this work was to characterize the changes in microstructure and chemical composition of the austenitic overlays on a pressure vessel steel that occur in the vicinity of the interface between the overlay and the base material. The investigations were carried out on a 16Mo3 boiler pipes weld overlaid by 309 and 310 steels. The microstructural examinations were performed on longitudinal cross-sectioned samples. The qualitative and quantitative chemical composition analyses on metallographic samples were determined on Scanning Electron Microscopy (SEM) by means of Energy Dispersive Spectrometry (EDS). The article analyzes the influence of the solidification sequence in both types of steel on final microstructure.
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Authors and Affiliations

M. Rozmus-Górnikowska
1
S. Dymek
1
M. Blicharski
1
Ł. Cieniek
1
J. Kusiński
1

  1. AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, al. A. Mickiewicza 30, 30-059 Krakow, Poland
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Abstract

Heat consumption and steel loss for scale determine the costs of a heating process. The heating rate influences both. This paper evaluates the heating rate of a long charge made of three various materials, depending on the changes of the furnace atmosphere on the rotary furnace circumference. Numerical computing was performed based on a formulated heat transfer model in the rotary furnace chamber, while considering the growth of the scale layer. One heating curve was selected, which has allowed the heating time to be reduced by 36% while limiting the scale loss by 40%. It was also shown that the thermal stresses and strains should not lead to fractures of the charge heated.
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Authors and Affiliations

B. Hadała
1
ORCID: ORCID
M. Rywotycki
1
ORCID: ORCID
Z. Malinowski
1
ORCID: ORCID
Sz. Kajpust
2
S. Misiowiec
2

  1. AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Krakow, Poland
  2. Zarmen FPA Sp. z o.o., 39 Filarskiego Str., 47-330, Zdzieszowice, Poland
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Abstract

In this paper one presents the new concept of a rocker-bogie suspension where the suspension members can change their length. As a result of this action the frame with suspension is able to adjust to the specific environmental conditions. The main problem with the designed suspension system is a fact that with an extension of the suspension members their slenderness increases as well as final displacements. The solution of this problem is not so simple because the construction must meet the specific requirements due to participation of the mobile platform in different competitions. In the presented results of numerical simulations one shows an influence of the different materials on stress and displacements magnitudes of suspension members when the mobile platform hits an obstacle. This situation allows one to test different engineering solutions in the worst case scenario when suspension elements may be damaged. Finally the optimum design is presented.
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Authors and Affiliations

K. Sokół
1
ORCID: ORCID
M. Pierzgalski
1
ORCID: ORCID

  1. Czestochowa University of Technology , Department of Mechanics and Machine Design Foundations , 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland
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Abstract

This work concerns the study of the coatings for the ultrasound frequency range as a quasi one-dimensional phononic crystal structure protecting a sea object against high resolution active sonar in the frequency range most commonly found for this type of equipment. The topology of the examined structure was optimized to obtain a band gap in the 2.2-2.3 MHz frequency band. For this purpose, a genetic algorithm was used, which allows for optimal distribution of individual elements of the ultrasound multilayer composite. By optimal distribution is meant to achieve a structure that will allow minimal reflectance in a given frequency range without height reflectance peaks with a small half width. Analysis of the wave propagation was made using the Transfer Matrix Method (TMM). As part of the research, 15 and 20-layer structures with reflectance at the level of 0.23% and 0.18%, respectively, were obtained. Increasing the number of layers in the analyzed structures resulted in finding such a distribution in which a narrow band of low reflectance was obtained, such distributions could also be used as bandpass filters. The use of a genetic algorithm for designing allows to obtain modern coatings, the characteristics of which result from the structure.
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Authors and Affiliations

S. Garus
1
ORCID: ORCID
W. Sochacki
1
ORCID: ORCID
J. Garus
1
ORCID: ORCID
A.V. Sandu
2
ORCID: ORCID

  1. Czestochowa University of Technology, Department of Mechanics and Fundamentals of Machinery Design, Faculty of Mechanical Engineering and Computer Science, 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland
  2. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Blv d. D. Mangeron 71, 700050 lasi, Romania
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Abstract

The article presents the results of model research concerning the change of technology of argon blowing into liquid steel at the ladle furnace, using the dual plug system. The results of numerical simulations were verified with experimental data carried out on the water model device. The verified model was used to perform numerical simulations to predict the impact of using a new gas injection technology – with different flow rates – on the time to achieve the assumed degree of metal chemical homogenization after alloy addition. Simulation results show that argon blowing metal bath in dual plug mode can effectively reduce mixing time compared to conventional technology with the same gas flow rates. Generally, the use of the dual plug system is beneficial for reducing the bath mixing time, however, the assumed optimal proportion of gas blown through individual plug should be followed. Finally, numerical predictions were used to perform experimental melt under industrial conditions. Industrial verification has clearly confirmed the validity of numerical modeling and showed that also in industrial conditions, a shorter time of chemical homogenization was obtained for the dual plug system.
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Authors and Affiliations

M. Warzecha
1
A. Hutny
1
P. Warzecha
1
Z. Kutyła
2
T. Merder
3

  1. Czestochowa University of Technology, Faculty of Production Engineering and Materials Technology, 19 Armii Krajowej Av., 42-200 Czestochowa, Poland
  2. CMC Poland Sp. z o.o., 82 Piłsudskiego Str., 42-400 Zawiercie, Poland
  3. Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, 8 Krasinskiego Str., 40-019 Katowice, Poland
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Abstract

The paper presents the results of tests on dynamic stability of Bernoulli-Euler beam with damages. Damages (cracks) were modeled using three rotational springs. An analysis of the influence of crack depth and their position relative to the beam ends on dynamic stability of the beam was carried out. The problem of dynamic stability was solved by applying the mode summation method. Applying an orthogonal condition of eigenfunctions, the dynamic of the system was described with the use of the Mathieu equation. The obtained equation allowed the dynamic stability of the tested system to be analyzed. Stable and unstable solutions were analyzed using the Strutt card.
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Authors and Affiliations

W. Sochacki
1
ORCID: ORCID
S. Garus
1
ORCID: ORCID
J. Garus
1
ORCID: ORCID

  1. Czestochowa University of Technology, Department of Mechanics and Fundamentals of Machinery Design, Faculty of Mechanical Engineering and Computer Science, 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland
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Abstract

The article has been devoted to issues connected with socket fusion welding, which is next to welding one of the methods of thermoplastic polymers joining. In this paper, the research was presented, which the aim was analysis of quality of joints obtained as a result of resistance welding of polypropylene pipes with diameter ø20 in the temperature range of 200÷230°C. To that end a Testo thermal imaging camera was used, flexural strength of the combined components was tested as well as the received weld was observed under a stereoscopic microscope. Conducted studies showed that the best results of joint are obtained during welding at 220°C and 230°C, while lower temperatures did not fully perform their function during the process of joining the pipe elements.
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Authors and Affiliations

A. Kalwik
1
ORCID: ORCID
K. Mordal
1
ORCID: ORCID
J. Redutko
1
ORCID: ORCID

  1. Czestochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation,21 Armii Krajowej Av., 42-201 Czestochowa, Poland
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Abstract

The subject of the study was to determine the impact of changes in mechanical properties of high-tin bronzes on the basic components of the sound of a bell. Change in the tin concentration in the range of about 7.5 to 20 parts wt. in a casting alloy significantly affects the mechanical properties of the alloy such as Young’s modulus or hardness. The free vibrations of bells were obtained with the help of the finite element method. In the numerical analyses the mechanical properties of standard alloys were adopted. The obtained natural frequencies of the bell made of a bronze with different tin concentration in copper were compared with the acoustic properties of a real bell casted on the basis of the same ribs. A significant effect of the increase in the alloying share of tin on the obtained results was stated. In addition, the acoustic analysis of aluminum bronze C95500 have been performed. Based on the obtained results, authors stated that this material can replace the commonly used high tin bronze C91300 for the unit production of bells.
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Authors and Affiliations

D. Cekus
1
ORCID: ORCID
M. Nadolski
2
ORCID: ORCID

  1. Czestochowa University of Technology, Department of Mechanics and Machine Design Fundamentals, 73 Dąbrowskiego S tr., 42-201 Czestochowa, Poland
  2. Czestochowa University of Technology, Faculty of Production Engineering and Materials Technology, 19 Armii Krajowej Av., 42-200 Czestochowa, Poland
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Abstract

The article has been devoted to issues connected with the alloplasty and hip joint endoprostheses, that elements are being developed, which is supported by strength, tribological tests on used biomaterials, incl. polyethylene or computer modelling based on e.g. finite element method (FEM). In this paper, the results of research on the impact of the material articulations of the system head – acetabular and friction conditions on strength parameters of polyethylene components in the hip joint endoprosthesis. Numerical analysis of this friction node was carried out, using the ADINA System computer program and the simulations were performed at various friction conditions for metal/ polyethylene and ceramic/ polyethylene articulations with various UHMWPE modifications. The simulations results have shown the influence of tested material associations and friction conditions on parameters related to the strength of polyethylene cups, i.e. their displacements, stresses and deformations.
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Authors and Affiliations

K. Mordal
1
ORCID: ORCID
A. Szarek
1
ORCID: ORCID

  1. Czestochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation,21 Armii Krajowej Av., 42-201 Czestochowa, Poland
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Abstract

In this investigation, Copper Matrix Surface Composites (CMSCs) were reinforced with various ceramic particles like Aluminum Nitrate (AlN), Titanium diboride (TiB2), and Rice Husk Ash (RHA) are used to increase the metallurgical and mechanical properties by Friction Stir Processing (FSP). The Design of the Experiment (DOE) Taguchi L9 orthogonal array method was used. The process parameters considered were groove width and various types of reinforcement particles. The fabrication of CMSCs was achieved by using optimized process parameters, such as the tool transverse speed of 40 mm/min, rotational tool speed of 1000 rpm, and an axial load of 10 kN with one pass. The influence of FSP process parameters on CMSCs in the stir zone is observed through Optical Microscope (OM), Field Emission Scanning Electron Microscope (FESEM), and Transmission Electron Microscope (TEM). Mechanical properties such as microhardness and wear rate are studied and compared. It reveals that good interfacial bonding was produced between ceramic particles in CMSCs. TiB2 reinforced with copper matrix surface composites enhance microhardness and had a lesser wear rate.
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Authors and Affiliations

S. Saravanakumar
1
ORCID: ORCID
S. Gopalakrishnan
2
ORCID: ORCID
K. Kalaiselvan
3
ORCID: ORCID

  1. Department of Mechanical Engineering, M. Kumarasamy College of Engineering, Karur, Tamilnadu, India
  2. Department of Mechanical Engineering, KS Rangasamy College of Technology, Tiruchengode, Tamilnadu, India
  3. Department of Mechanical Engineering, Dr. NGP Institute of Technology, Coimbatore, Tamilnadu, India
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Abstract

Growing awareness for occupational safety in the welding environment needs a sustainable welding system. Welding gases releases toxic tiny particles and gases that inflict severe health consequences in the weld zone are unsolicited. Some of the other main adverse effects are lung disease, hemoptysis, pulmonary inflammation, pneumoconiosis, etc. GMAW procedure has been used for welding 316L stainless steel plates of 3 mm, 5 mm, and 6 mm. Various current configurations with gas flow rate of 5 LPM, 10 LPM and 15 LPM were also used to achieve optimum butt joint performance and to reduce the production rate of fume contributing to cost-effectiveness. In this research a cost-effective fume extraction hood was fabricated for measuring Emission factor produced during welding. Various shielding gas compositions including Pure Argon, Pure CO2, 92% Ar+8% CO2 and 88% Ar+12% CO2 were used to determine the best operating parameters in the GMAW method. To satisfy the latest Permissible Exposure Limit (PEL) legislation, optimum technical parameters for efficient welding were acknowledged with the lowest emission factor. A maximum reduction of Emission factor can be achieved by using Pure Argon. The inclusion of CO2 as a shielding gas mixture gives higher emission factor when compared to Pure Argon. Very low emission factor were witnessed in this research when compared to previous investigations. Lower emission factor of 2941.17 mg /kg of electrode, 4411.76 mg/kg of electrode and 7352.94 mg/kg of electrode were obtained for pure argon as shielding gas with 150 A welding current.
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Authors and Affiliations

K.V. Satheesh Kumar
1
ORCID: ORCID
P. Selvakumar
2
ORCID: ORCID
K.R. Uvanshankar
1
ORCID: ORCID
S. Thirunavukarasu
1
ORCID: ORCID
V. Vijay Anand
1
ORCID: ORCID
D. Vishal
1
ORCID: ORCID

  1. Department of Mechanical Engineering, Kongu Engineering College, Erode- 638060, Tamilnadu, India
  2. Department of Chemistry, Vivekanandha College of Arts & Sciences for Women, Tiruchengode- 637205, Tamilnadu, India
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Abstract

This paper deals with the subject of high temperature analysis of refining slags originating from a ladle from an actual/industrial secondary refining process. The objective of the conducted research was to learn about the rheological behaviour of the complex industrial slag systems analysed in conditions of variable rheological parameters and temperature, also analyses with a high-temperature microscope. The analysed system seems to be a Newtonian body (with viscosity between 0.1 and 0.8 Pa·s, depend on temperature value, and chemical composition).
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Authors and Affiliations

M. Ślęzak
1
ORCID: ORCID
M. Karbowniczek
1
ORCID: ORCID
P. Migas
1
ORCID: ORCID
W. Ślęzak
1
ORCID: ORCID

  1. AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland
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Abstract

The present research employs the statistical tool of Response surface methodology (RSM) to evaluate the machining characteristics of carbon nanotubes (CNTs) coated high-speed steel (HSS) tools. The methodology used for depositing carbon nanotubes was Plasma-Enhanced Chemical Vapor Deposition (PECVD). Cutting speed, thickness of cut, and feed rate were chosen as machining factors, and cutting forces, cutting tooltip temperature, tool wear, and surface roughness were included as machining responses. Three-level of cutting conditions were followed. The face-centered, Central Composite Design (CCD) was followed to conduct twenty number of experiments. The speed of cutting and rate of feed have been identified as the most influential variables over the responses considered, followed by the thickness of cut. The model reveals the optimized level of cutting parameters to achieve the required objectives. The confirmation experiments were also carried out to validate the acceptable degree of variations between the experimental results and the predicted one.
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Authors and Affiliations

Chandru Manivannan
1
ORCID: ORCID
Selladurai Velappan
2
ORCID: ORCID
Venkatesh Chenrayan
3
ORCID: ORCID

  1. Dhirajlal Gandhi College of Technology, Salem – 636309, Tamilnadu, India
  2. Coimbatore Institute of Technology, Coimbatore – 641014, Tamilnadu, India
  3. Adama Science and Technology University, Adama, Ethiopia
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Abstract

TiAl based intermetallics are widely used for structural applications in aviation, chemical engineering, automotive and sports equipment. In this study, the electrical resistance sintering (ERS) technology used in the production of gamma-TiAl intermetallics is based on the principle of applying pressure simultaneously with a high-density electric current. The purpose of this study was to investigate the cyclic oxidation resistance of Ti-44Al-3Mo and Ti-44Al-3Nb alloys (at.%) and the applicability of artificial neural network (ANN) modeling for the forecast of the oxidation behavior of these alloys. In order to obtain this aim, the alloys sintered by ERS were oxidized at 900°C for 360 h and then the oxidation behaviors of them are evaluated by plotting a graph between weight change as a function of time. The data collected after the oxidation experiments were used to construct the prediction models. The modelling results show that a good agreement between experimental results and prediction results was found. The oxidized alloys were characterized using XRD and SEM-EDS. The XRD patterns revealed the oxidation products are composed of TiO2 and Al2O3 oxides. SEM-EDS analysis indicated that the oxide scales of alloys are made up of a multilayered structure.
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Authors and Affiliations

Y. Garip
1
ORCID: ORCID
Z. Garip
2
ORCID: ORCID
O. Ozdemir
1
ORCID: ORCID

  1. Sakarya Applied Science University, Technology Faculty , Department of Metallurgy and Materials Engineering, Esentepe Campus, 54187, Sakarya -Turkey
  2. Sakarya Applied Science University, Technology Faculty, Department of Computer Engineering, Esentepe Campus, 54187, Sakarya -Turkey
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Abstract

Thermal spraying methods are commonly used to regenerate damaged surface or change materials surface properties. One of the newest methods is cold spraying, where coating is deposited of material in the solid state. Therefore shape and size of the powder particles are very important parameters. The article presents the influence of copper powder morphology on mechanical properties of the coatings (adhesion, hardness, Young’s modulus) deposited with the Low Pressure Cold Spraying method on the AA1350 aluminium alloy substrate. The coatings were deposited using two commercially available copper powders with spherical and dendritic morphology and granulation of –40+10 µm. The bond strength of coatings was determined with the pull off method, the hardness with the Vickers method at load of 2.94 N, while the Young’s modulus through measurement of nanoindentation. Microstructure of the coatings was analysed using the light and scanning electron microscopy (SEM). Shape of the powder influences mechanical properties of the coating significantly. The coatings deposited with dendritic powder had low mechanical properties, hardness of the 81 HV0.3 order and adhesion of about 4 MPa. However changing powder morphology to spherical increased hardness of the coating to 180 HV0.3 and adhesion to 38.5 MPa.
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Authors and Affiliations

D. Grygier
1
ORCID: ORCID
M. Rutkowska-Gorczyca
1
ORCID: ORCID
M.G. Winnicki
2
ORCID: ORCID
T. Wojdat
2
ORCID: ORCID

  1. Wroclaw University of Science and Technology, Faculty of Mechanical Engineering, Department of Vehicle Engineering, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
  2. Wroclaw University of Science and Technology, Faculty of Mechanical Engineering, Department of Metal Forming, Welding and Metrology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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Abstract

The analysis of the development of the microstructure of deep drawn automotive B pillar, as well as the analysis of deformation based on numerical simulation and experiment, was performed. The microstructure of steel sheet as well as Al-Si coating after various stages of B pillar production was investigated. It was found that the obtained microstructure of the B pillar was significantly different from that described in many studies as a proper one. The microstructure of the investigated material consisted of martensite, bainite, and a small amount of ferrite. Al-Si coating, despite its morphological changes, remained on the surface of B pillar and, in spite of this, did not fully eliminate oxidation and decarburization of B pillar material. The analysis of the state of strain allowed to evaluate the deformation safety of the process, as well as to verify the simulation results through measurements of sheet thickness variations.
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Authors and Affiliations

M. Paćko
1
ORCID: ORCID
J. Krawczyk
1
ORCID: ORCID
T. Śleboda
1
ORCID: ORCID
T. Frocisz
1
ORCID: ORCID
Maciej Rumiński
ORCID: ORCID
O. Lypchanskyi
1
T. Tokarski
1
ORCID: ORCID
P. Piasecki
2

  1. AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland
  2. Kirchhoff Automotive, Mielec, Poland

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