bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of salinity on coupled nitrification and aerobic denitrification in an estuarine system
Authors: Yang Mengfan , Xue Dongmei , Meng Fanqiao , Wang Zhong-Liang
Published: June 2015

Salinity has significant effects on nitrification and denitrification processes, particularly in estuarine systems. A dissolved oxygen-enriched river and its estuary in northern China were selected to investigate the impact of salinity gradients (0.6, 4, 7.6, 11.4 and 14.7‰) obtained from the mixing of river samples and estuarine samples with different proportions on coupled nitrification and aerobic denitrification via incubation experiments (35 and 10 °C). Results indicated that: (a) nitrification and coupled nitrification-aerobic denitrification occurred for all treatments, which resulted in NO3− being either accumulated or removed at the end of the incubation; (b) a suitable range of salinity is 4.0–11.4‰ for nitrification and 4.0–7.6‰ for coupled nitrification-aerobic denitrification; and (c) the relatively higher temperature (35 °C) can effectively stimulate N transformation processes compared to the lower temperature (10 °C) in the incubation experiment.
Generational Differences in Work Values in China
Authors: Chen Jian , Lian Rong
Published: June 2015

We examined the generational differences in Chinese employees' work values using the Chinese Work Values Scale with 1,015 Chinese employees across three generations (i.e., Cultural Revolution generation, n = 148; Transitional generation, n = 355; Millennial generation,
n = 512). We found that, even with gender, education, and position taken into account, the Millennial generation placed more importance on intrinsic and extrinsic rewards than did the Transitional generation or the Cultural Revolution generation, and that the Cultural Revolution generation
placed more importance on altruism than did the younger generations. Results also showed that generation exerted more influence on work values than did age. This implies that, taking these results into account, current human resource management practices in organizations and institutions in
China should be adjusted accordingly.
Benefits of Distraction
Authors: Von Gehlen Johannes , Sachse Pierre
Published: June 2015

A considerable amount of research has been carried out with the aim of understanding the relationship between arousal and performance, but so far this topic has rarely been examined in the context of personality. In this study, we used a 2-group design (N = 76) to investigate
the effects of arousal, induced by cognitive activation, on introverts and extroverts in the context of follow-up tasks. Arousal was induced by an irrelevant auditory stimulus that implemented a high cognitive load while participants were attempting to remember the content of the text of an
article. Extroverts showed a greater improvement in performance than did introverts in a consecutive task, a d2-Test of Attention, leading to the conclusion that extroverts benefit more from cognitive activation through external stimuli than do introverts. Theoretical implications are discussed
in the framework of the Yerkes–Dodson law.
Does thrombolytic therapy harm or help in ST elevation myocardial infarction (STEMI) caused by the spontaneous coronary dissection?
Authors: Jovic Zoran , Obradovic Slobodan , Djenic Nemanja , Mladenovic Zorica , Djuric Predrag , Spasic Marijan , Tavciovski Dragan
Published: June 2015

Introduction. Spontaneous coronary artery dissection (SCAD) is a very rare
disease with poor prognosis. It mainly affects young women free of risk
factors for coronary artery disease (CAD) and women during the peripartum
period. The prognosis for myocardial infarction caused by SCAD is poor,
management is often difficult and guidelines still missing. Case report. We
presented a woman with acute myocardial infarction of anterior wall of the
left ventricle, caused by spontaneous dissection of medial segment of the
left anterior descending coronary artery. We treated the patient with
thrombolytic therapy and performed coronary angiography after that. Finally
we decided to do nothing more. Two years later we performed coronary
angiography again and founded the coronary artery normal. We also analyzed
19 cases publiched from 1996 to 2012 when coronary artery dissection had
been treated with thrombolytic agent. Analysis revealed only one case of 19,
with complication after treating SCAD with thrombolysis. Conclusion.
Sometimes, regarding myocardial infarction in young women with no risk
factors for CAD, especially in young women in peripartum, we should think
about SCAD. The presented case, like eight others, demonstrates that good
clinical outcomes can be achieved with thrombolysis. In spite of all this,
we still need more data to verify that thrombolysis does not have to harm
the therapy for SCAD. For the time being thrombolytic therapy could be an
option.
Transcatheter closure of atrial septal defect in a patient with Noonan syndrome after corrective surgery
Authors: Mangovski Ljupco , Farkic Mihajlo , Jovovic Ljiljana
Published: June 2015

Introduction. Transcatheter atrial septal defect (ASD) closure is considered
to be a gold standard for patients with the suitable anatomy as compared to
cardiac surgery. Reocurrence of ASD after surgical closure is a very rare
late complication which can be successfully managed with transcatheter
procedure. Case report. We reported a female patient with Noonan syndrome who
presented with hemodinamically significant ASD 37 years after the corrective
cardiac surgery. Due to numerous comorbidities which included severe
kyphoscoliosis, pectus excavatum and multiple surgeries we decided to perform
transcatheter closure of ASD. The procedure itself was very challenging due
to the patient?s short stature and heart?s orientation in the chest, but was
performed successfully. The subsequent follow-up was uneventful and the
patient reported improvement in the symptoms. Conclusion. Transcatheter
closure of ASD in a patient with Noonan syndrome with the history of
surgically corrected ASD can be performed successfully, despite challenging
chest anatomy.
Joining of multiple sheets in a butt-joint configuration using single pass laser welding with multiple spots
Authors: Hansen K. S. , Olsen F. O. , Kristiansen M. , Madsen O.
Published: June 2015

The introduction of high-power single mode fiber lasers has given deeper and narrower welds than previously seen using lasers. In some cases, the weld becomes too narrow and must be expanded to fit the geometrical shape of a given welding task. Instead of using only one beam, it was suggested to split the beam into multiple spots placed in a prespecified pattern. In this way, the dimensions of the weld pool could be controlled. In this work, the spots are placed on a row perpendicular to the welding direction. This provided the ability to control the final weld face by controlling the width and depth of penetration independent of each other with minimum heat input. An examination was conducted on how the weld cross section is influenced by spot distance, number of spots, power, and focus. It is shown that a weld seam can be widened in steps by using multiple spots, and the depth can be controlled independently from the width by adjusting the laser power. It is possible to produce a rectangular like cross section of the weld by choosing correct design parameters. For a pattern with multiple spots on a row, equal depth of penetration in the weld bead is reached if the edge spots have 5%–10% more power than the center spots. Basic rules for design of spot patterns are given for a configuration with a single mode laser and spot diameter of Ø85 μm. The ability to bridge gaps is increased in multispot welding compared to multiple single passes. The technique shows promising results in welding parts which resembles the conditions of a real production regarding robustness and tolerances.
Adsorption and corrosion inhibition behavior of stainless steel 316 by aliphatic amine compounds in acidic solution
Authors: Goudarzi N. , Peikari M. , Zahiri M. Reza , Mousavi H. Reza
Published: June 2015

Gravimetric and electrochemical measurements were performed to investigate the effectiveness of an aliphatic amine compound with trade name of Armohib 28. It was found that the percentage inhibition efficiency increased with the increase of the compound concentration. Polarization curves indicate that the inhibitor under investigation acts as cathodic type which retards the rate of corrosion reactions by adsorbing on to the steel surface according to Langmuir adsorption isotherm. The activation energy and thermodynamic parameters were calculated and analyzed. The data obtained from electrochemical impedance spectroscopy (EIS) were analyzed to model the corrosion inhibition process through equivalent circuit.
Cermet ESD coatings modified by laser treatment
Authors: Radek N. , Konstanty N.
Published: June 2015

The main objective of the present work was to determine the influence of laser treatment on microstructure, microhardness, roughness, bonding strength, corrosion resistance and tribological properties of wear resistant coatings produced on C45 carbon steel by the electro-spark deposition (ESD) process. Consumable WC-Co-Al2O3 electrodes were prepared by the powder metallurgy route and transferred to the substrate surface using the EIL-8A apparatus. The cermet layers were subsequently melted by means of the BLS 720 Nd:YAG laser. The coating characterisation studies showed marked improvements in the bonding between the steel substrate and the cermet coating, and in corrosion resistance at the expense of higher surface roughness and minor drop in the Vickers microhardness.
Control over the steel welding structure parameters by micro-jet cooling
Authors: Wegrzyn T. , Piwnik J. , Wieszała R. , Hadrys D.
Published: June 2015

The paper presents the characteristics of innovative technology of micro-jet cooling in MIG welding (according to PN-EN ISO 4063:2009). Presented results received at different jet hole geometry and various coolant pressure. This technology allows get, with appropriately selected parameters of cooling increased ferrite AF content in weld metal, up to 14% for standard MIG technology. This structure proves toughness, especially at temperature -40°C.
Influence of number of ECAP passes on microstructure and mechanical properties of AZ31 magnesium alloy
Authors: Bryła K. , Dutkiewicz J. , Litynska-Dobrzynska L. , Rokhlin L.L. , Kurtyka P.
Published: June 2015

The aim of this work was to investigate the influence of the number of equal channel angular pressing (ECAP) passes on the microstructure and mechanical properties of AZ31 magnesium alloy. The microstructure after two and four passes of ECAP at 423 and 523 K was investigated by means of optical and transmission electron microscopy. The mechanical properties were carried out using Vickers microhardness measurements and compression test. The grain refinement in AZ31 alloy was obtained using ECAP routes down to 1,5 μm at 423 K. Processes of dynamic recrystallization during ECAP were observed. It was found that a gradual decrease of grain size occurs with the increasing of number of ECAP passes. The grain refinement increases mechanical properties at ambient temperature, such as Vickers microhardness and compression strength proportionally to d-0.5.
Analysis of forging process of the NiCrN superalloy for motor boat driving shaft
Authors: Swiatoniowski A. , Sinczak J. , Łukaszek-Sołek A. , Schmidt J.
Published: June 2015

Superalloys containing nickel and chromium display high deformation resistance and low plasticity during high-rate plastic forming processes, thus limiting the potentials to improve their mechanical parameters. At the aim to overcome this problem an NiCrN superalloy has been found. In this paper the analysis of forging of this NiCrN superalloy has been presented. Mathematical FEM model of the process are verified by experimental tests run on a double-acting power hammer. Tests reveal, that plastic working of the NiCrN alloy combined with thermal treatment improves its strength by nearly 25%, at the same time its plastic deformability remains the same. Research work has revealed very high resistance to corrosion of the alloy when subjected to stress and marine environment.
Fuzzy reasoning system design and assessment of load-bearing endoprostheses and their fabrication processes
Authors: Sobieszczyk S.
Published: June 2015

Five attempts of an application of a fuzzy reasoning approach to problems encountered in biomechanics and engineering of biomaterials are presented. They include: (A) assessment of maximum contact stress acting on endoprosthesis, (B) design of sintering plan to obtain a porous/scaffold implant, (C) design of oxidation plan to obtain nanotubular oxide structure on the Ti alloy, (D) and (E) design of deposition of hydroxyapatite coating on the Ti alloy. The fuzzy reasoning system is shown to well predict: the maximum contact stress estimation on acetabular surface of the load-bearing hip joint endoprosthesis for chosen and given Wiberg’s angle values and patient’s body weight; the optimal geometry of scaffold’s architecture; the geometry of TiO2 nanotubular layer on titanium surface and directions of the adjustment of fabrication conditions; the ratio of Ca/P and the coating crystallinity; effects of control factors (sintering temperature and content of ZnO) on mechanical properties of BHA-ZnO composite. A small deviation of the predicted values from those obtained in the course of experiments can be decreased by improvement of the proposed fuzzy model i.e. adjusting fuzzy membership functions of input and output variables.
Activity of zinc in the liquid Bi-In-Sn-Zn alloys determined by knudsen method
Authors: Zajaczkowski A. , Gasior W. , Onderka B.
Published: June 2015

The Knudsen effusion method was used for measurements of mass loss rate of liquid Bi-In-Sn-Zn alloys, in the temperature range from 572 to 768 K. The studies were carried out for the alloys with the ratio of Bi:In:Sn equal 2:6:2, 2:2:6 and 8:1:1. The obtained results were used for the calculation of zinc vapour pressure over liquid Bi-In-Sn-Zn alloys and next the activity of zinc in the Bi-In-Sn-Zn liquid phase. It was found that for the investigated alloys the activity of zinc shows the considerable positive deviation from the Raoult’s law.
Microstructure and mechanical properties of fine-grained iron processed by hydroextrusion
Authors: Romelczyk B. , Kulczyk M. , Pakieła Z.
Published: June 2015

The aim of this study was to characterize the microstructure and properties of fine-grained iron. The samples were prepared by sintering at 1000°C ±5°C for 30 minutes, followed by Severe Plastic Deformation via Hydrostatic Extrusion (HE). After the sintering the rod samples were capsulated to prevent damage during extrusion. HE has been applied as a final consolidation process of iron powders. The HE process was carried out on two extrusion passes. The rods of 8 mm in diameter were obtained as a final product after hydroextrusion. The total cumulative strain was 2.3. Materials in three states were investigated: sintered, sintered and deformed by one hydrostatic extrusion pass, and two hydrostatic extrusion passes. The results were compared with the results obtained for coarse-grained Armco iron. The measurements showed that the grain size was reduced from 3.5 μm after sintering to 180±81 nm after the 2nd extrusion pass. The tensile strength and microhardeness increased with cumulative strain of the material. The impact test carried out at -196°C showed transformation of the fracture mechanism from cleavage for coarse-grained structure to ductile for extruded material.

W pracy scharakteryzowano mikrostrukture i mechaniczne własciwosci ultradrobnoziarnistego spieku zelaza. Próbki przygotowano w dwóch etapach - wypraski spieczono w temperaturze 1000°C ±5°C w czasie 30 minut, a nastepnie spieki odkształcono metoda wyciskania hydrostatycznego [HE]. W celu unikniecia pekania spieków proces wyciskania przeprowadzono na próbkach uprzednio zakapsułkowanych. Proces HE przebiegał w dwóch etapach a skumulowane odkształcenie wyniosło 2.3. srednica koncowego produktu wyniosła 8 mm.

W pracy przedstawiono wyniki badan zarówno spieku, jak i materiału po poszczególnych wyciskaniach hydrostatycznych. Wyniki badan ujawniły redukcje rozmiaru ziaren zelaza z 3.5 μm po spiekaniu do 180 nm po drugim wyciskaniu HE. Zarówno wytrzymałosc ja i mikrotwardosc wzrosły ze stopniem skumulowanego odkształcenia próbek.

Wyniki badan udarnosciowych porównano z wynikami otrzymanymi dla gruboziarnistego zelaza Armco. Badania udarnosci metoda Charpiego przeprowadzono na próbkach uprzednio chłodzonych w ciekłym azocie. Obserwacje mikroskopowe przełomów próbek po udarnosci wykazały zmiane charakteru pekania zelaza z łupliwego dla materiału gruboziarnistego na ciagliwy dla materiału ultradrobnoziarnistego.
Experimental Tests for Cross Wedge Rolling of Forgings Made from Non-Ferrous Metal Alloys / Próby Doświadczalne Walcowania Poprzeczno-Klinowego Odkuwek Ze Stopów Metali Nieżelaznych
Authors: Pater Z. , Tomczak J.
Published: June 2015

Reported in this paper are the experimental test results for hot cross wedge rolling of elementary shaft forgings made from light metal alloys which are widely used in aviation industry, such as aluminum alloys 6101A and 2618A, titanium alloy Ti6Al4V as well as magnesium alloys AZ31 (Mg 3Al-1Zn-Mn), AZ61 (Mg 6Al-1Zn-Mn) and Mg4AlZnMn. The research works were conducted by means of a flat-wedge rolling mill LUW-2, with typical wedge tools used. The experiment tests involved the analysis of force parameters, geometrical parameters, and process stability. The conducted experimental tests prove the feasibility of forming axially symmetric parts made from light metal alloys in CWR (cross wedge rolling) processes. Limitations upon the application of CWR technologies to forming such alloys are also described.
Impact of Mould Powder on Slab Lubrication / Wpływ Zasypki Krystalizatorowej Na Smarowanie Płaskiego Wlewka Ciągłego
Authors: Kania H. , Nowacki K.
Published: June 2015

The paper presents results of industrial experiments with application of mould powders characterized with similar chemical composition, with different density and form: pulverized, granulated and formed. Impact of mould powder form on intensity of lubrication and its consumption is defined on the basis of the results of industrial tests of continuous casting of low carbon steel, 1030×220 mm format.
Analysis of the Impact of Surface Layer Parameters on Wear Intensity of Friction Pairs / Analiza Wpływu Parametrów Warstwy Wierzchniej Na Intensywność Zużycia Par Ciernych
Authors: Burdzik R. , Folęga P. , Łazarz B. , Stanik Z. , Warczek J.
Published: June 2015

The study discussed in the paper consisted in testing the impact of surface layer parameters on wear intensity of friction pair components. The study was conducted having taken additional operational factors into consideration, namely the friction conditions (presence of lubricant) and the value of loads affecting the contact zone of the samples being tested. The study constituted laboratory tests of wear and were conducted by means of a T-01M type laboratory test stand used to experimentally analyse frictional cooperation of various materials used in structural components of motor vehicles. The friction pairs examined were previously operating in a pin-on-disk system under various conditions. The materials of the friction pairs tested at the stand were subjected to heat treatment and chemical processing in order to attain specific parameters of their surface layers. The studies conducted enabled determination of the abrasive wear values for the material samples tested having entailed the surface layer parameters and the factors related to operation of actual structural components used in automotive engineering. An additional advantage of the studies conducted was the possibility to establish actual coefficients of friction occurring in specific friction pairs. Establishing the actual values of friction coefficients for the materials of friction pairs under specific conditions and having taken the impact of the surface layer parameters into consideration enabled identification of the reasons for excessive surface wear. Hence a reference can be made between the stationary tests undertaken and actual components cooperating with one another in kinematic pairs of machines. The utilitarian premise resulting from the studies conducted is the necessity of paying particular attention to surface layer parameters while designing friction pairs for machines.
Investigations of α + β → β Phase Transformation in Monotonically Heated Ti6Al7Nb Alloy / Badania Przemiany Fazowej α + β → β W Stopie Ti6Al7Nb Przy Nagrzewaniu Ciągłym
Authors: Dąbrowski R.
Published: June 2015

This paper presents an evaluation of critical temperatures of α + β → β phase transformation in an Ti6Al7Nb alloy occurring during heating performed by dilatometric and metallographic methods. Also, changes in the alloy microstructure during cooling down from the two-phase (α + β) and single phase (β) ranges have been analysed. In the microstructure of the alloy quenched from temperature above 1010°C (one-phase range) in water, the very fine, needle-like precipitates (presumably α’) were observed as well as abnormal grain growth of the primary β phase. The obtained results may serve for the interpretation of phase transformation occurring in the Ti6Al7Nb alloy during tempering. In future, the kinetics of the phase transformation during tempering will be investigated by original CHT (Continuous-Heating-Transformation) charts, which are commonly applied for iron-base alloys.
Atmosphere Effect on Sintering Behaviour of Astaloy CrM and Astaloy CrL Höganäs Powders with Manganese and Carbon Additions / Wpływ Atmosfery Na Spiekalność Komercyjnych Proszków Höganäs Astaloy CrM I Astaloy CrL Z Dodatkami Manganu I Węgla
Authors: Pieczonka T. , Sułowski M. , Ciaś A.
Published: June 2015

Dilatometric data for Astaloy CrM (3% Cr-0.5% Mo) and Astaloy CrL (1.5% Cr-0.2% Mo) powders with additions of 0.3% carbon and 3.0% manganese during sintering cycles up to 1120 and 1250°C in different atmospheres are reported. For comparison, also Astaloy CrM and Astaloy CrL powders were investigated. Starting with green densities of approx. 6.8 g/cm3, the final density of sintered compacts was influenced mainly by the sintering temperature, while the results showed the only minor effect of the sintering atmosphere on the final dimensional changes. However, the sintering atmosphere influences the sintering behaviour, microstructure and the final chemical composition of sintered compacts. In sintered and in the dilatometer cooled Mn-Cr-Mo-C steels predominantly bainitic structures were obtained.
XAFS in the Tracking of Reactions in Aqueous Solution: a Case of Redox Reaction Between [AuCl4]– Complex Ions and Ethanol / Metoda XAFS W Badaniach Reakcji Zachodzących W Roztworach Wodnych: Przykład Reakcji Redoks Pomiędzy Jonami Kompleksowymi [AuCl4]- I Alkoholem Etylowym
Authors: Pacławski K. , SIKORA M.
Published: June 2015

In this work the potential application of synchrotron radiation in the studies of reaction kinetics in aqueous phase were presented. After short introduction describing principles of technique and potential application of XAFS for the structural studies of reacting species, the experimental results of kinetic measurements of reaction between gold(III) chloride complex ions and ethanol were presented. Analyzing the changes of absorption intensity in the XANES spectra registered at Au-L3 edge during the reaction, the change of the valence state of Au central atom (form 3+to 0) of reacting complex ion was determined. Moreover, empirical XANES data gave the chance to register the kinetic curve and to determine the rate constant of the studied reaction. It was found that reaction is relatively slow (second-order rate constant k = 3.66 · 10-5 M-1s) and lead to the gold metallic phase formation in the system. Applying the continuous-flow method, within the first 600 ms of reaction the changes in XANES spectra were registered. From the obtained results, supported with numerical calculations, two intermediate forms of adducts appearing prior the electron transfer were suggested. It was concluded that when the classic methods, e.g. UV-Vis spectrophotometry, cannot be applied to studies of kinetics of reactions in aqueous solution, the XAFS technique can be a valuable and substitutive (or supplementary) tool for such measurements.
Deformation of Ferrite-Austenite Banded Structure in Cold-Rolled Duplex Steel / Odkształcenie Pasmowej Struktury Ferrytu I Austenitu W Walcowanej Na Zimno Stali Duplex
Authors: Ryś J. , Zielińska-Lipiec A.
Published: June 2015

Duplex type ferritic-austenitic stainless steels develop a specific two-phase banded structure upon thermo-mechanical pre-treatment and subsequent cold-rolling. The band-like morphology of ferrite and austenite imposes different conditions on plastic deformation of both constituent phases in comparison to one-phase ferritic and austenitic steels.

In the present research the ingot of a model ferritic-austenitic steel of duplex type, produced by laboratory melt, was subjected to preliminary thermo-mechanical treatment including forging and solution annealing. Afterwards cold-rolling was conducted over a wide deformation range. The investigations comprised examination of ferrite and austenite microstructures by means of optical and transmission electron microscopy and texture measurements after selected rolling reductions.

The presented results indicate that deformation mechanisms operating within the bands of both constituent phases are essentially the same as compared to one-phase steels, however their appearance and contribution are changed upon deformation of two-phase banded structure. Different deformation behavior within ferrite-austenite bands in duplex steels, visible especially at higher strains, considerably affects microstructure evolution and in consequence texture formation in both phases.
Microstructure and Phase Transformations Near the Bonding Zone of Al/Cu Clad Manufactured by Explosive Welding / Zmiany Mikrostrukturalne I Fazowe W Pobliżu Strefy Połączenia Układu Warstwowego Al/Cu Wytworzonego Technologią Zgrzewania Wybuchowego
Authors: Paul H. , Lityńska-Dobrzyńska L. , Miszczyk M. , Prażmowski M.
Published: June 2015

The structure near the interface of bimetallic strips strongly influences their properties. In this work, the interfacial layers of explosively welded aluminium and copper plates were investigated by means of a scanning electron microscope (SEM), equipped with a high resolution system for local orientation measurements (SEMFEG/EBSD), and a transmission electron microscope (TEM), equipped with energy dispersive spectrometry (EDX) for the analysis of chemical composition changes.

The SEMFEG/EBSD-based local orientation measurements in the areas close to the interface, in both sheets, revealed fine-grained layers characterized by the clearly marked tendency of the copper-type rolling texture formation. The texture was described by an increased density of the orientations near the {112}<111>, {123}<634>and {110}<112>positions. The internal microstructure of the intermetallic inclusion is mostly composed of dendrites. The electron diffractions and the TEM/EDX chemical composition measurements in the intermetallic inclusions revealed only crystalline phases, both equilibrium and ’metastable’. Additionally, no significant regularity in the phase distribution with respect to the parent sheets was observed.
Numerical Simulation of the Molten Steel Flow in the Tundish of CSC Machine / Symulacja Numeryczna Przepływu Ciekłej Stali W Kadzi Pośredniej Urządzenia COS
Authors: Sowa L. , Bokota A.
Published: June 2015

The mathematical and numerical simulation model of the liquid steel flow in a tundish is presented in this paper. The problem was treated as a complex one. The velocity fields are obtained by solving the momentum equations and the continuity equation, whereas the thermal fields are calculated by solving the conduction equation with the convection term. One takes into consideration in the mathematical model the changes of thermophysical parameters depending on the temperature. The problem was solved by the finite element method. The one-strand slab tundish is used to casting slabs. The internal work space of the tundish was modified by flow control devices. The first device was a striker pad situated in the pouring tundish zone. The second device was a baffle with three holes. The main purpose of using these was to put barriers in the steel flow path as well as give directional metal flow upwards which facilitated inclusion floatation. The visualization of interaction of flow control devices on hydrodynamic conditions was received from numerical simulations. As a result of the computations carried out, the liquid steel flow and steel temperature fields were obtained. The influences of the tundish modifications on the velocity fields in liquid phase of the steel were estimated, because these have essential an influence on high-quality of a continuous steel cast slab.
Modeling of Thermomechanical Phenomena of Welding Process of Steel Pipe / Modelowanie Zjawisk Termomechanicznych Procesu Spawania Rury Stalowej
Authors: Kulawik A.
Published: June 2015

In this paper an analysis of phenomena of laser welding of steel thin-walled element is presented. Coupled mathematical and numerical models of thermal phenomena, mechanical and phase transitions in solid and liquid state are proposed. To the modeling of phase transformation in the solid state the macroscopic model based on the analysis of the CTP diagrams are used. In the simulation of thermal phenomena the solution of heat transport equations with melting and solidification model is applied. Mechanical phenomena using the stress model for a elastic-plastic range and the isotropic strengthening of material are simulated. In order to solve analyzed problem the software using the finite element method (3D problem)has been developed. The influence of the individual elements of the model on the stress field and the plastic deformation field of welded steel element is determined. A comparative analysis of the results of numerical calculations for the case: the dependence of material properties on the temperature, the inclusion of phase transformation in the solid state, the dependence of the yield strength on the phase composition of the material are made.
Microstructure and Plasticity of Hot Deformed 5083 Aluminum Alloy Produced by Rapid Solidification and Hot Extrusion / Badania Mikrostruktury I Plastyczności Odkształcanego Na Gorąco Szybko-Krystalizowanego I Wyciskanego Stopu Aluminium 5083
Authors: Tokarski T. , Wzorek Ł. , Dybiec H.
Published: June 2015

The objective of the present study is to analyze the mechanical properties and thermal stability for rapidly solidified and extruded 5083 aluminum alloy (RS). Compression tests were performed in order to estimate flow stress and strain rate sensitivity relation for 5083 alloy in the temperature range of 20°C to 450°C. For the comparison purposes, conventionally cast and extruded industrial material (IM) was studied as well. Deformation tests performed at room temperature conditions show that rapidly solidified material exhibits about 40% higher yield stress (YS=320 MPa) than conventionally cast material (YS=180 MPa), while the deformation at 450°C results in significant decrease of flow stress parameters for RS material (YS=20 MPa) in comparison to IM material (YS=40 MPa). Strain rate sensitivity parameter determined for high temperature conditions indicates superplasticity behavior of RS material. Structural observations show that under conditions of high-temperature deformation there are no operating recrystallization mechanisms. In general, grain size below 1µm and size of reinforcing phases below 50 nm is preserved within the used deformation temperature range.
Training Effect on Speech Rhythm of Nepalese Non-Native Speakers of English
Authors: Aryal Ananda
Published: June 2015

This project aimed to ascertain the effect of training on speech rhythm of Nepalese non-native speakers of English. Six Nepalese and one native speaker of English participated in this research. A six-week training program was administrated and pre- and post-training guided speech samples were acoustically analysed. Acoustic measurement of the pre- and post-training speech samples showed that training played an important role in improving the rhythm of Nepalese non-native speakers of English. DOI: http://dx.doi.org/10.3126/nelta.v19i1-2.12077 Journal of NELTA, Vol 19 No. 1-2, December 2014: 17-31
Using Non-native English Films to Promote Multiculturalism in ELT Classroom
Authors: Idris Nazua
Published: June 2015

This paper aims to present how the incorporation of non-native English films can enhance the multicultural awareness among the English language learners. As the non-native English films expose the students to linguistic and cultural diversity, they can be used as effective tools in designing materials for ELT classroom. To demonstrate how teachers can incorporate these films in their classroom, the paper discusses various approaches to design materials for language classroom, and contains three sample lesson plans for intermediate, upper-intermediate and advanced level students. The lesson plans exploit a number of non-native English films to generate a discussion of different cultures along with teaching English language. Finally, the paper ends with some suggestions for the teachers. DOI: http://dx.doi.org/10.3126/nelta.v19i1-2.12081 Journal of NELTA, Vol 19 No. 1-2, December 2014: 65-76
Classroom Implementation Practices of the Secondary Level English Curriculum: A Case of Nepal
Authors: Karki Manita
Published: June 2015

Curriculum is a whole educational programme to fulfil the objectives of national educational system that provides the fundamental frame for the teachers to teach in schools. The school level English language curriculum in Nepal aims at developing a comprehensive communicative competence in learners. This paper attempts to explore the extent to which English language teachers teaching at secondary level in Nepal understand the English curriculum and implement it in their classroom teaching. The paper is based on my graduate research project at Kathmandu University which involved eight English-language teachers from the Kathmandu valley for interview and observation to collect required information. The paper accomplishes the thesis that EFL teachers make sense of knowledge of curriculum at theoretical level; however it has not been utilized, as it should be, in their classroom practices. DOI: http://dx.doi.org/10.3126/nelta.v19i1-2.12083 Journal of NELTA, Vol 19 No. 1-2, December 2014: 88-98
Examining the Discourse of Perfume Advertisements: An Analysis of the Verbal and the Visual
Authors: Lunyal Vandana
Published: June 2015

In the world that promotes consumerism, companies are in a competition to produce a variety of commodities and to convert people into consumers of their products whether they need them or not. The abundance of consumer products is promoted through advertisements. These advertisements persuade the common people to become consumers for which they use a variety of strategies, the most common being the use of problem-solution format in language and an effective use of the verbal and the non-verbal. This paper focuses on investigating the verbal and the non-verbal aspects of the text to examine how ideological constructs function in the discourse of advertisingthrough the use of hegemony. A perfume advertisement has been selected for a detailed analysis of the verbal and the visual elements to illustrate how advertisers commonly attempt to transmit some underlying, yet unasserted, meanings to unsuspecting readers who may understand the intentions of the advertisers i.e. to promote consumption but may not understand that the aim is achieved by generally promoting cultural stereotypes which work towards the disadvantage of one social group vis-à-vis the other especially the one that the advertisement is addressed to. The tool for the analysis of the advertisement is Fairclough’s model of critical discourse analysis (CDA) that uses the analysis of the verbal and the visual to reveal ideological underpinnings. CDA also has pedagogical implications for instance the language used for describing products, if analysed critically by language learners, helps them to unfold the hidden meanings as is illustrated through the analysis. DOI: http://dx.doi.org/10.3126/nelta.v19i1-2.12085 Journal of NELTA, Vol 19 No. 1-2, December 2014: 117-131
Teachers’ Attitudes towards Critical Pedagogy and its Practice in ELT Classrooms
Authors: Paudel Jagqadish
Published: June 2015

Critical Pedagogy (CP), a mode of pedagogy, aims to empower learners and provide justice by offering preferential options and deconstructing authoritative and logo centric tendency in education. The current study, by using a mixed methodological design (qualitative and quantitative), illustrates a group of Nepali English language teachers’ attitudes regarding CP in ELT, focusing on how they employ CP in their classrooms. For this research, a sample of 10 teachers was purposively selected from Baitadi and Dadeldhura districts. Five teachers’ classes were observed. Analyzing the data collected through a survey questionnaire, it was found that all the teachers are in favour of CP in most cases in ELT. Even if all the teachers were notionally appeared in favor of practicing CP in most of the aspects that were asked to them, quite contrary to it, observation results of the teachers’ classes revealed that they did not, in any real sense, embrace CP in their teaching practice. Hence, this study invoked the ELT teachers to embrace CP practically in the classrooms. DOI: http://dx.doi.org/10.3126/nelta.v19i1-2.12086 Journal of NELTA, Vol 19 No. 1-2, December 2014: 132-146
The Use of English Prepositions: An Empirical Study
Authors: Saravanan J
Published: June 2015

This study examined the writing skill of the students at the undergraduate level, with a special focus on the use of prepositions of place, time and direction in English. The subjects of the study comprised of 100 randomly selected students of English literature from two Arts and Science colleges located in Coimbatore city. The data elicitation instrument was a guided cloze test in which the subjects were asked to fill the gaps using appropriate prepositions of place, time and direction. To analyze the collected data, socio-linguistic and descriptive methods were used. The results indicated that the students found more difficulties in the use of prepositions of place and direction than the prepositions of time because of their mother tongue interference. The findings imply that teachers should pay more attention while teaching the prepositions of place, time and direction and provide sufficient explanations about them to the students in the classroom. DOI: http://dx.doi.org/10.3126/nelta.v19i1-2.12089 Journal of NELTA, Vol 19 No. 1-2, December 2014: 158-168
Effects of a Sprinkler on Evacuation Dynamics in Fire
Authors: Yamamoto Kazuhiro , Takeuchi Yuki , Nishiki Shinnosuke
Published: June 2015

A fire in an enclosed space, such as a room in a building, is generally called a compartment fire. To prevent the compartment fire, a sprinkler for first-aid fire-fighting is installed in rooms. However, it is difficult to determine the degree to which smoke generation and the fire spreading will be inhibited when sprinklers are on. In particular, demonstrating evacuation behavior assuming an actual fire is impossible. In this study, we evaluated an effectiveness of the sprinkler by numerical simulations. To consider evacuation dynamics, a real-coded cellular automata (RCA) was used, where we can freely set the direction and velocity of an evacuee based on a floor field model. To consider the situation in the room fire, we used a simulator called Fire Dynamics Simulator (FDS). Two cases with and without the sprinkler were compared to see the validity of the sprinkler on evacuation dynamics. The effect of smoke and the expansion of the fire-spreading region were discussed. Results show that, since the fire-spreading region disappears when the sprinkler is actuated, the evacuation time decreases. Even though the sprinkler is actuated, the smoke generated at the beginning of a fire diffuses inside the whole room. However, the duration of evacuees being overwhelmed by smoke is less, because the amount of smoke generated by the pyrolysis reaction is much decreased.
A Robust Bayesian Approach to an Optimal Replacement Policy for Gas Pipelines
Authors: Arias-Nicolás José , Martín Jacinto , Ruggeri Fabrizio , Suárez-Llorens Alfonso
Published: June 2015

In the paper, we address Bayesian sensitivity issues when integrating experts’ judgments with available historical data in a case study about strategies for the preventive maintenance of low-pressure cast iron pipelines in an urban gas distribution network. We are interested in replacement priorities, as determined by the failure rates of pipelines deployed under different conditions. We relax the assumptions, made in previous papers, about the prior distributions on the failure rates and study changes in replacement priorities under different choices of generalized moment-constrained classes of priors. We focus on the set of non-dominated actions, and among them, we propose the least sensitive action as the optimal choice to rank different classes of pipelines, providing a sound approach to the sensitivity problem. Moreover, we are also interested in determining which classes have a failure rate exceeding a given acceptable value, considered as the threshold determining no need for replacement. Graphical tools are introduced to help decisionmakers to determine if pipelines are to be replaced and the corresponding priorities.
Sustainability Assessment of a Self-Consumption Wood-Energy Chain on Small Scale for Heat Generation in Central Italy
Authors: Verani Stefano , Sperandio Giulio , Picchio Rodolfo , Marchi Enrico , Costa Corrado
Published: June 2015

The sustainability of a small-scale self-consumption wood-energy chain for heat generation in central Italy was analyzed from a technical, economic and energetic point of view. A micro-chain was developed within the CRA-ING farm at Monterotondo (Rome, Italy): The purpose of this system was to produce biomass for supplying a heating plant within the CRA-ING property as a substitute for diesel fuel. A poplar short rotation coppice, established with clones AF2, AF6 and Monviso, fed the micro-chain. The rotation was biennial. The average plantation production (Mgd.m.·ha−1·year−1) was 10.2, with a maximum of 13.53 for the twin-rows AF2 and a minimum of 8.00 for the single-row Monviso. The economic assessment was based on the Net Present Value (NPV) method and the equivalent annuity cost, and found an average saving of 15.60 €·GJ−1 of heat generated by the wood chips heating system in comparison with the diesel heating system over a 10 year lifetime of the thermal power plant. The energy assessment of the poplar plantation, carried out using the Gross Energy Requirements method, reported an energy output/input ratio of 12.3. The energy output/input ratio of the whole micro-chain was 4.5.
Should Law Keep Pace with Society? Relative Update Rates Determine the Co-Evolution of Institutional Punishment and Citizen Contributions to Public Goods
Authors: Roithmayr Daria , Isakov Alexander , Rand David
Published: June 2015

Until recently, theorists considering the evolution of human cooperation have paid little attention to institutional punishment, a defining feature of large-scale human societies. Compared to individually-administered punishment, institutional punishment offers a unique potential advantage: the ability to control how quickly legal rules of punishment evolve relative to social behavior that legal punishment regulates. However, at what rate should legal rules evolve relative to society to maximize compliance? We investigate this question by modeling the co-evolution of law and cooperation in a public goods game with centralized punishment. We vary the rate at which States update their legal punishment strategy relative to Citizens’ updating of their contribution strategy and observe the effect on Citizen cooperation. We find that when States have unlimited resources, slower State updating lead to more Citizen cooperation: by updating more slowly, States force Citizens to adapt to the legal punishment rules. When States depend on Citizens to finance their punishment activities, however, we find evidence of a ‘Goldilocks’ effect: optimal compliance is achieved when legal rules evolve at a critical evolutionary rate that is slow enough to force citizens to adapt, but fast enough to enable states to quickly respond to outbreaks of citizen lawlessness.
Urotensin II Protects Cardiomyocytes from Apoptosis Induced by Oxidative Stress through the CSE/H2S Pathway
Authors: Gong Hui , Chen Zhidan , Zhang Xiaoyi , Li Yang , Zhang Jie , Chen Ying , Ding Yingjiong , Zhang Guoping , Yang Chunjie , Zhu Yichun , Zou Yunzeng
Published: June 2015

Plasma urotensin II (UII) has been observed to be raised in patients with acute myocardial infarction; suggesting a possible cardiac protective role for this peptide. However, the molecular mechanism is unclear. Here, we treated cultured cardiomyocytes with H2O2 to induce oxidative stress; observed the effect of UII on H2O2-induced apoptosis and explored potential mechanisms. UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H2O2; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H2O2. SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects. Further analysis revealed that UII increased the production of hydrogen sulfide (H2S) and the level of cystathionine-γ-lyase (CSE) by activating the ERK signaling in H2O2-treated-cardiomyocytes. Si-CSE or ERK inhibitor not only greatly inhibited the increase in CSE level or the phosphorylation of ERK induced by UII but also reversed anti-apoptosis of UII in H2O2-treated-cadiomyocytes. In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H2S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress. These results suggest that increased plasma UII level may protect cardiomyocytes at the early-phase of acute myocardial infarction in patients.
Genotype by Environment Interaction for Growth in Atlantic Cod (Gadus morhua L.) in Four Farms of Norway
Authors: Bangera Rama , Drangsholt Tale , Nielsen Hanne , Sae-Lim Panya , Ødegård Jørgen , Puvanendran Velmurugu , Hansen Øyvind , Mortensen Atle
Published: June 2015

We studied genotype by environment interaction (G × E) for body weight (BW) of Atlantic cod (Gadus morhua L.) from the National cod breeding program in Norway. Records of 13,811 fish in a nucleus farm (NUC) and two test farms (PENorth, PESouth) in year-class (YC) 2007, and for 9149 fish in NUC and one test farm in YC 2010 were available. Heterogeneity of variances and heritabilities ( ) were estimated using a univariate animal model with environmental effects common to full-sibs (full-model). Genetic correlations ( ) between farms were estimated using a multivariate full-model and a reduced-model (without ) for each YC. Heterogeneity of was observed in both YC 2007 (0.10 to 0.16) and YC 2010 (0.08 to 0.26). The estimates of between NUC and test farms were relatively high for both models (0.81 ± 0.19 to 0.96 ± 0.17) and (0.81 ± 0.08 to 0.86 ± 0.04), suggesting low re-ranking of genotypes. Strong re-ranking of genotypes between PESouth and PENorth may be less important because most cod producers are situated close to the breeding nucleus. In conclusion, G × E between NUC and test farms were low and at present there is no need for separate breeding programs for BW in cod.