bluuebunny/crossref_metadata_2025_split huggingface dataset:
Welding of Prosthetic Alloys
Authors: Wojciechowska M. , Wołowiec E. , Klimek L. 
Published: April 2015

Abstract
This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was assessed compared to the solid metal. The experiments have shown that the metal elements used to make dentures, joined by the technique which employs a laser beam, have better strength properties than those achieved with a gas burner.
Comparison of Properties of Polymer Composite Materials Reinforced with Carbon Nanotubes
Authors: Zygoń P. , Gwoździk M. , Peszke J. , Nitkiewicz Z. 
Published: April 2015

Abstract
Carbon nanotubes because of their high mechanical, optical or electrical properties, have found use as semiconducting materials constituting the reinforcing phase in composite materials. The paper presents the results of the studies on the mechanical properties of polymer composites reinforced with carbon nanotubes (CNT). Three-point bending tests were carried out on the composites. The density of each obtained composite was determined as well as the surface roughness and the resistivity at room temperature.
Moreover the surface studies on an atomic forces microscope (AFM) and X-ray studies (phase composition analysis, crystallite sizes determination) were carried out on such composites. Measurements of the surface topography using the Tapping Mode method were performed, acquiring the data on the height and on the phase imaging. The change of intensity, of crystallite size and of half-value width of main reflections originating from carbon for composites have been determined using the X-ray analysis.
Carbon nanotubes constituting the reinforcement for a polymer composite improve the mechanical properties and con-ductivity of the composite.
The Use of Barium and Calcium Alloys in the Ladle Furnace Treatment of Selected Grades of Continuously Cast Steels
Authors: Derda W. , Lawenda P. , Pardela P. 
Published: April 2015

AbstractThe subject of the paper are the results of laboratory and industrial investigations into the use of Si - Ca - Ba alloys for modifying non-metallic inclusions. Based on laboratory tests, the morphology and chemical composition of non-metallic inclusions in carbon steel were examined before and after refining with the use of the above-mentioned alloy as a refining addition. In particular tests, variable additions of the alloy were used at a constant refining time and temperature.Comparison of the process of casting of a sequence of seven heats of the same steel grade using the stopper system in the tundish was made under industrial conditions. In these heats, additions of Si - Ca (three heats) and Si - Ca - Ba (four heats) were introduced as a non-metallic inclusion modifier in the form of core wires during the process in the ladle furnace. For the investigated heats, the contents of total oxygen and calcium were assayed in the finished steel. A significant effect of the simultaneous addition of barium and calcium on steel castability, and thus on the process of continuous casting of the investigated heats, was found.
Corrosion Resistance of High-Alloyed White Cast Iron
Authors: Kawalec M. , Krawiec H. 
Published: April 2015

Abstract
The paper presents the results of corrosion resistance tests carried out on high-alloyed white cast iron. Tests were performed in 0.1 M NaCl by the technique of linear voltammetry. The test material was collected from six high-vanadium cast iron melts with a variable content of carbon and vanadium, and thus with different microstructure. Studies have confirmed that the type of crystallised microstructure has a very important effect on the alloy corrosion resistance. The highest corrosion resistance showed the alloy with a ferritic matrix containing the spheroidal precipitates of vanadium carbide VC, while the lowest had the eutectic alloy with a pearlitic matrix.
Structure Analysis and Properties of Unleaded Brasses
Authors: Rzadkosz S. , Kozana J. , Garbacz-Klempka A. , Piękoś M. 
Published: April 2015

Abstract
The analysis of brasses regarding their microstructure, mechanical properties and ecological characteristics has been presented. The influence of characteristic alloying elements contained in the brasses and the possibilities of replacing them with other elements have been assessed. The paper contains the results of studies on the influence of chosen additional elements shaping the structure and properties of unleaded alloys based on Cu-Zn system as the matrix. The research aimed at determining the mechanism and the intensity of influence of such additives as tellurium and bismuth. The microstructures were investigated with the help of light microscopy and scanning electron microscopy with X-ray microanalysis (SEM-EDS) for determining significant changes of the properties.
Amorphous Dielectric Thin Films with Extremely Low Mechanical Loss
Authors: Liu X. , Queen D.R. , Metcalf T.H. , Karel J.E. , Hellman F. 
Published: April 2015

Abstract
The ubiquitous low-energy excitations are one of the universal phenomena of amorphous solids. These excitations dominate the acoustic, dielectric, and thermal properties of structurally disordered solids. One exception has been a type of hydrogenated amorphous silicon (a-Si:H) with 1 at.% H. Using low temperature elastic and thermal measurements of electron-beam evap-orated amorphous silicon (a-Si), we show that TLS can be eliminated in this system as the films become denser and more structurally ordered under certain deposition conditions. Our results demonstrate that TLS are not intrinsic to the glassy state but instead reside in low density regions of the amorphous network. This work obviates the role hydrogen was previously thought to play in removing TLS in a-Si:H and favors an ideal four-fold covalently bonded amorphous structure as the cause for the disappearance of TLS. Our result supports the notion that a-Si can be made a “perfect glass” with “crystal-like” properties, thus offering an encouraging opportunity to use it as a simple crystal dielectric alternative in applications, such as in modern quantum devices where TLS are the source of dissipation, decoherence and 1/f noise.
Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension
Authors: Granata M. , Balzarini L. , Degallaix J. , Dolique V. , Flaminio R. , Forest D. , Hofman D. , Michel C. , Pedurand R. , Pinard L. , Sassolas B. , Straniero N. , Teillon J. , Cagnoli G. 
Published: April 2015

Abstract
In order to study the internal friction of thin films a nodal suspension system called GeNS (Gentle Nodal Suspension) has been developed. The key features of this system are: i) the possibility to use substrates easily available like silicon wafers; ii) extremely low excess losses coming from the suspension system which allows to measure Q factors in excess of 2×108 on 3” diameter wafers; iii) reproducibility of measurements within few percent on mechanical losses and 0.01% on resonant frequencies; iv) absence of clamping; v) the capability to operate at cryogenic temperatures. Measurements at cryogenic temperatures on SiO2 and at room temperature only on Ta2O5 films deposited on silicon are presented.
Separate Kinetics of the Polar and Antiferrodistortive Order Parameters in the Antiferroelectric Transition of PbZr1-xTixO3 and the Influence of Defects
Authors: Cordero F. , Craciun F. , Trequattrini F. , Galassi C. 
Published: April 2015

Abstract
The transition from the rhombohedral-ferroelectric to the lower temperature orthorhombic-antiferroelectric phase in Zr-rich PZT involves two order parameters (OPs): 1) the polar OP for the displacements of the cations with respect to the O octahedra; 2) an antiferrodistortive OP responsible for tilting of the octahedra. It is shown that at Ti compositions near the morphotropic boundary with the FE phase (0.046 ≤ x ≤ 0.054), the two OPs may be almost independent of each other at cooling rates of 0.5 K/min or faster, depending on the sample history. This fact gives rise to a great variety of shapes of the curves of the elastic compliance s(T), but all of them can be fitted very well as superpositions of variously broadened steps for each of the modes involved in the transitions, including the tilt transition occurring in the untransformed FE fraction. The evolution of the s(T) curves includes enhancements up to a factor of four during aging for weeks in the region of the AFE/FE coexistence. Restiffening and reduction of the thermal hysteresis of the AFE/FE transition are recovered by heating up to 800-900 K. It is proposed that ageing is due to the clustering of relatively mobile defects, most likely O vacancies, at the domain walls in the coexisting AFE/FE phases. Such defect structures are probably at the origin of intense thermally activated relaxation processes observed above TC in the dielectric and anelastic spectra, and can be annealed out above 800 K, allowing the AFE transition to recover a fast kinetics.
Estimation of the Level of Residual Stress in Wires with a Magnetic Method
Authors: Suliga M. , Borowik L. , Chwastek K. 
Published: April 2015

AbstractResidual stress present in wires after drawing process affects their magnetic properties. The paper presents a concept to estimate the level of residual stress on the basis of measurements of hysteresis loops. In order to describe the effect qualitatively the Jiles-Atherton-Sablik description is adapted. On the basis of variations in hysteresis loop shapes the average values of residual stress in wires for different single draft values are determined. It was found that the estimated average values by magnetic stresses are comparable with the results of numerical modeling and experimental studies.
Numerical Analysis of the Skew Rolling Process for Rail Axles
Authors: Pater Z. , Tomczak J. , Bulzak T. 
Published: April 2015

Abstract
The paper describes a new method for producing stepped rail axles. The method is based on the skew rolling process. With this method, the product is formed by three tapered rolls located every 120° on the perimeter of the billet. Positioned askew to the centerline of the billet, the rolls rotate in the same direction and with the same velocity. At the same time, they get closer together or go apart depending on the desired cross sectional reduction of an axle step. In addition, the workpiece is shifted lengthwise relative to the rolls by the translational motion of the workpiece-holding chuck. In order to verify the designed method for producing rail axles, a series of numerical simulations were performed using the Simufact. Forming v.12 simulation software. The numerical modeling enabled the determination of maps of the effective strain and temperature in the finished product as well as variations in the loads and torques during rolling. The numerical results unambiguously confirm that the skew rolling method can be applied to form parts of considerable dimensions (the modeled axles had a length of 2146 mm and their maximum diameter was 202 mm).
Theoretical and Experimental Research on Forge Rolling Process of Preforms From Magnesium Alloy AZ31
Authors: Bulzak T. , Tomczak J. , Pater Z. 
Published: April 2015

Abstract
This paper presents results of theoretical and experimental research works on the rolling process of a lever preform from magnesium alloy AZ31. The forge rolling process of the preform was realized in the system oval-circle. The paper focuses mainly on kinematics of material flow and proper filling of rolling impressions. Research aiming at determining possibilities of faults presence in the form of cracks, overlapping and improper filling of the impressions were also conducted. During experimental research it was noticed that material cracking took place at the moment of material clamping by rolls. Moreover, it was stated that this cracking may be the result of large shearing stresses action, appearing at the moment of material clamping by rolls. Shearing stresses values were determined on the basis of numerical calculations. Next, tools were modified in order to lower tangential stresses at the moment of material clamping by rolls. The further experimental research with modified tools confirmed the rightness of the assumptions. On the basis of conducted works on the forge rolling process of magnesium alloy AZ31, it was stated that when material is clamped by tools tangential stresses intensification should not take place.
Thermal Stability of Nanocrystalline Structure In X37CrMoV5-l Steel
Authors: Skołek E. , Marciniak S. , Świątnicki W.A. 
Published: April 2015

AbstractThe aim of the study was to investigate the thermal stability of the nanostructure produced in X37CrMoV5-1 tool steel by austempering heat treatment consisted of austenitization and isothermal quenching at the range of the bainitic transformation. The nanostructure was composed of bainitic ferrite plates of nanometric thickness separated by thin layers of retained austenite. It was revealed, that the annealing at the temperature higher than temperature of austempering led to formation of cementite precipitations. At the initial stage of annealing cementite precipitations occurred in the interfaces between ferritic bainite and austenite. With increasing temperature of annealing, the volume fraction and size of cementite precipitations also increased. Simultaneously fine spherical Fe7C3carbides appeared. At the highest annealing temperature the large, spherical Fe7C3carbides as well as cementite precipitates inside the ferrite grains were observed. Moreover the volume fraction of bainitic ferrite and of freshly formed martensite increased in steel as a result of retained austenite transformation during cooling down to room temperature.
Corrosion Resistance of Co-Cr-Mo Alloy Used in Dentistry
Authors: Łukaszczyk A. , Augustyn-PieniąŻek J. 
Published: April 2015

Abstract
The presented paper studies the effect of the casting technology on the corrosion resistance of Co-Cr-Mo alloy. The investigations were conducted on a commercial alloy with the brand name ARGELOY N.P SPECIAL (Co-Cr-Mo) produced by Argen as well as the same alloy melted and cast by the lost wax casting method performed by a dental technician. The corrosion behavior of the dental alloys in an artificial saliva was studied with the use of the following electrochemical techniques: open circuit potential and voltammetry. After the electrochemical tests, studies of the surface of the examined alloys were performed by means of a scanning electron microscope with an X-ray microanalyzer. The results of the electrochemical studies show that the dependence of the corrosion resistance on the microstructure associated with the recasting process is marginal. The results of the electrochemical studies of the considered alloy clearly point to their good corrosion resistance in the discussed environment.
Multiple solutions for a class of oscillatory discrete problems
Authors: Mălin Maria 
Published: April 2015

AbstractIn this paper, we study a discrete nonlinear boundary value problem that involves a nonlinear term oscillating at infinity and a power-type nonlinearity up. By using variational methods, we establish the existence of a sequence of non-negative weak solutions that converges to +∞ if 0 < p ≤ 1. In the superlinear case, we establish a sufficient condition for the existence of at least n solutions.
Challenges in Design and Automation of Autonomous Waterborne Vehicles
Authors: Ritz Sebastian , Thiede Carl , Boeck Florin , Golz Matthias , Holbach Gerd 
Published: April 2015

Abstract
Autonomous waterborne vehicles are complex technical systems, which operate in a harsh environment. This article sensitizes to the
special challenges and requirements and gives an approach for further considerations. Additionally, some automation components,
especially developed for this kind of application and first practical experiences are presented.
Heterogeneous Effects of Informational Nudges on Pro-social Behavior
Authors: Bao Jiayi , Ho Benjamin 
Published: April 2015

Abstract
Numerous experimental studies of informational nudges both in the lab and the field have demonstrated not just that informational nudges are effective policy tools for influencing behavior, but also that nudges have heterogeneous impacts that differ depending on the characteristics of the person involved and the situation. We adapt Andreoni’s theory of warm-glow impure altruism to account for how altruism motives respond differently depending on the disposition of the person and the situation. The model explains both positive spillovers (moral cleansing) and negative spillovers (moral licensing) for behavioral interventions, showing that targeting of informational campaigns depends on the complementarity between people’s traits and the intervention’s content. More importantly, the design of economic incentives (like Pigouvian taxes) to shift economic behavior should depend on both the distribution of social preferences in the population and the use of behavioral interventions.
The Transmission of Education across Generations: Evidence from Australia
Authors: Ranasinghe Rasika 
Published: April 2015

Abstract
This study analyzes changes in the transmission of education across generations in Australia for the birth cohorts 1942 through 1991 using a range of measures: the estimated effect of parental education on that of the child, schooling correlations between parents and children and a series of mobility indices. Our results suggest that while the overall level of education and intergenerational education mobility has increased over time, there are considerable regional and gender differences. Daughters’ education attainment is still relatively highly correlated with their parents compared to sons and the extent of absolute upward mobility was modest while immobility and downward mobility have remained relatively steady during the last five decades. During this period, relative education opportunities have increased over time at lower education levels, while the trend has been comparatively stable at higher levels.
Micellar Liquid Chromatography from Green Analysis Perspective
Authors: El-Shaheny Rania N. , El-Maghrabey Mahmoud H. , Belal Fathalla F. 
Published: April 2015

Abstract
Micellar liquid chromatography (MLC) is a simple well-established branch of high-performance liquid chromatography. The applications of MLC for the determination of numerous compounds in pharmaceutical formulations, biological samples, food, and environmental samples have been growing very rapidly. MLC technique has several advantages over other techniques, such as simultaneous separation of charged and uncharged solutes, rapid gradient capability, direct on-column injection of physiological fluids, unique separation selectivity, high reproducibility, robustness, enhanced luminescence detection, low cost, and safety. This review is devoted to the evaluation of the agreement of MLC with the principles of green chemistry which recently represents a universal trend. Also, it provides an overview on the basics of MLC, in addition to a survey of MLC methods published in the past five years for the assay of various compounds in different matrices.
Hybrid Particle Swarm Optimization and Ant Colony Optimization Technique for the Optimal Design of Shell and Tube Heat Exchangers
Authors: Lahiri Sandip K. , Khalfe Nadeem Muhammed 
Published: April 2015

Abstract
Owing to the wide utilization of shell and tube heat exchangers (STHEs) in industrial processes, their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which gradually change the design and geometric parameters until satisfying a given heat duty and set of geometric and operational constraints. Although well proven, this kind of approach is time-consuming and may not lead to cost-effective design. The present study explores the use of non-traditional optimization technique called hybrid particle swarm optimization (PSO) and ant colony optimization (ACO), for design optimization of STHEs from economic point of view. The PSO applies for global optimization and ant colony approach is employed to update positions of particles to attain rapidly the feasible solution space. ACO works as a local search, wherein ants apply pheromone-guided mechanism to update the positions found by the particles in the earlier stage. The optimization procedure involves the selection of the major geometric parameters such as tube diameters, tube length, baffle spacing, number of tube passes, tube layout, type of head, baffle cut, etc. and minimization of total annual cost is considered as design target. The methodology takes into account the geometric and operational constraints typically recommended by design codes. Three different case studies are presented to demonstrate the effectiveness and accuracy of proposed algorithm. The examples analyzed show that the hybrid PSO and ACO algorithm provides a valuable tool for optimal design of heat exchanger. The hybrid PSO and ACO approach is able to reduce the total cost of heat exchanger as compare to cost obtained by previously reported genetic algorithm (GA) approach. The result comparisons with particle swarm optimizer and other optimization algorithms (GA) demonstrate the effectiveness of the presented method.
Lp{L_{p}}-representations of discrete quantum groups
Authors: Brannan Michael , Ruan Zhong-Jin 
Published: April 2015

Abstract
Given a locally compact quantum group

𝔾

{\mathbb{G}}

, we define and study representations and

C
∗

{\mathrm{C}^{\ast}}

-completions of the convolution algebra

L
1

⁢

(
𝔾
)

{L_{1}(\mathbb{G})}

associated with various linear subspaces of the multiplier algebra

C
b

⁢

(
𝔾
)

{C_{b}(\mathbb{G})}

. For discrete quantum groups

𝔾

{\mathbb{G}}

, we investigate the left regular representation, amenability and the Haagerup property in this framework. When

𝔾

{\mathbb{G}}

is unimodular and discrete, we study in detail the

C
∗

{\mathrm{C}^{\ast}}

-completions of

L
1

⁢

(
𝔾
)

{L_{1}(\mathbb{G})}

associated with the non-commutative

L
p

{L_{p}}

-spaces

L
p

⁢

(
𝔾
)

{L_{p}(\mathbb{G})}

. As an application of this theory, we characterize (for each

p
∈

[
1
,
∞
)

{p\in[1,\infty)}

) the positive definite functions on unimodular orthogonal and unitary free quantum groups

𝔾

{\mathbb{G}}

that extend to states on the

L
p

{L_{p}}

-

C
∗

{\mathrm{C}^{\ast}}

-algebra of

𝔾

{\mathbb{G}}

. Using this result, we construct uncountably many new examples of exotic quantum group norms for compact quantum groups.
Twisted cubics on cubic fourfolds
Authors: Lehn Christian , Lehn Manfred , Sorger Christoph , van Straten Duco 
Published: April 2015

Abstract
We construct a new twenty-dimensional family of projective
eight-dimensional irreducible holomorphic symplectic manifolds: the
compactified moduli space

M
3

⁢

(
Y
)

M_{3}(Y)

of twisted cubics on a smooth cubic fourfold
Y that does not contain a plane is shown to be smooth and to admit a
contraction

M
3

⁢

(
Y
)

→

Z
⁢

(
Y
)

M_{3}(Y)\to Z(Y)

to a projective eight-dimensional symplectic
manifold

Z
⁢

(
Y
)

Z(Y)

. The construction is based on results on linear determinantal
representations of singular cubic surfaces.