bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulated Body Fluid Sorption and Solubility of Silica Reinforced Dental Resin Composites
Authors: Alsharif Saad Omar , Hazizan Md Akil , El-Aziz Nasser Abbas Abd , Ahmad Zainal Arifin
Published: September 2013

The aim of this study is to investigate the effect of filler loading on the sorption and solubility of Simulated Body Fluid (SBF) of self-prepared micro dental resin composites. The prepared resin composite was based on silica (SiO2) particles and bisphenol-a-glycidyl methacrylate (Bis-GMA) as a base monomer and triethylene glycol dimethacrylate (TEGDMA) as a co-monomer. The filler was mixed with monomers, in proportions of 40, 50 and 60 wt.%. A resin matrix containing 0 wt.% filler was used as the control composition to evaluate the effect of filler loading on the sorption and solubility of SBF. The experimental methods were based on the procedure mentioned in the ISO 4049 (2009) standard for dentistry-Polymer-based restorative Materials. The sorption and solubility of resin matrix/SiO2 composite decreased gradually as the filler loading increased. The increase of filler loading showed significant differences in the sorption and solubility as tested by ANOVA (P = 0.000).
Identification of Limiting Friction Coefficient towards Improved Hip Prostheses
Authors: Hafis Mohd Bin Sulaiman , Farahana R.N. , Ridzuan Mohd Jamir Mohd , Siti Mahani S.
Published: September 2013

Wear generated by the presence of friction on hip joint contact surfaces can cause debris, which may lead to loosening and failure of the hip prostheses. The objective of this study is to examine the limiting friction coefficient of the hip joint using Finite Element (FE) method. The hip joint model was developed to represent the contact surfaces between femoral head and inner socket, and the contact surfaces between inner socket and acetabular cup. The measured angle from 0° to 15° was applied to the inner socket for normal walking condition. The maximum contact pressure on the acetabular cup surface was found at the position angle of 10°. Therefore, further examination was carried out and the results showed that the highest friction coefficient of 0.4 was determined.
Ceramic Foam Filters in Runner System Design for Castings
Authors: Hsu Fu Yuan , Li Cheng Lung , Campbell John
Published: September 2013

In the design of runner systems, ceramic foam filters are used for reducing the velocity of liquid metal in order to avoid so called bifilm defect resulting from a high gating velocity (over its critical gating velocity) in aluminum gravity casting. In this study, two types of runner systems incorporated with the ceramic foam filters were designed. In order to observe the flow phenomena in these two runner systems with and without the filters, a water analogy experiment in a transparent plastic mold was utilized. Furthermore, in order to understand the effect of the filters used in these systems, an aluminum sand casting experiment was conducted. The quality of the cast metal in the outlet area of the filter for these systems was investigated. The defect content of this casting sample was measured by the re-melt reduced pressure test (re-melt RPT) and followed by measuring its bulk density. An optimized runner system with the filter was suggested in this study.

Keywords: ceramic foam filter, runner system design, gravity casting, critical gating velocity, bifilm defect.
Spray-Formed 50Si-50Al Alloy Deformed in the Semi-Solid State
Authors: Hsu Hong Chih , Tsao Chi Y.A.
Published: September 2013

50Si-50Al alloys were synthesized by the Spray Forming process, and were further deformed in the semi-solid state. The spray-formed microstructure consists of small equiaxed primary Si in 3-5 μm scale. For semi-solid deformation at 650°C at solid fraction (fs) of 0.4, the stress increases initially to reach the peak stress, then decreases to a plateau level, followed by last stage of stress climbing, and the effects of the deformation speeds on the stress level are significant, but not large. For deformation at 750°Cat fs of 0.31, the stress increases initially, then increases at a slower rate, followed by last stage of fast climbing, and the lower the deformation speed is, the higher the deformation stress. The average deformation stress needed at 650 °C was much higher that that needed at 750 °C. The deformation was inhomogeneous at 650°C to become pieces of connected semi-solid clusters, while the deformation was much more homogeneous at 750°C.
Design on Dynamic Performance of Highway Bridges to Moving Vehicular Loads
Authors: Gao Qing Fei , Wang Zong Lin , Guo Bin Qiang , Bu Hao Ran , Xiong Wei
Published: September 2013

Based on the survey of existing highway bridges, there are a large number of flaws induced by moving vehicles. The most important cause of this phenomenon is the lack of design codes on dynamic performance of highway bridges to moving vehicular loads. The existing theory of vehicle-bridge interaction is reviewed. Then the home-code program VBCVA combined with finite element program ANSYS is introduced to analyze the problem of vehicle-bridge interaction. Also, the existing design indexes of dynamic performance are discussed, such as dynamic impact factor, deflection limit, and acceleration. On the basis of above theory and program, the framework of design on dynamic performance of highway bridges to moving vehicular loads is proposed.
Reliability Prediction of Bridges Based on Monitored Data and Bayesian Dynamic Models
Authors: Fan Xue Ping , Lu Da Gang
Published: September 2013

Bridges are subjected to time-dependent loading and strength degradation processes. The main purposes of the designers and the owners are to keep these processes under control, to real-timely know and predict the structural time-variant reliability indices through health monitoring for bridge structures. The sensors of monitoring systems used in structural engineering provide data used for reliability prediction. But how to make use of monitored data to predict and make assessment of the time-variant reliability indices of bridges has become the bottleneck in the field of structural health monitoring (SHM). Bayesian dynamic models can combine the structural monitoring information with the structural reliability, and also can consider the uncertainty of the mass monitoring information. Therefore, in this paper firstly the bayesian dynamic model is built based on the monitoring information; secondly the monitoring mechanism of the monitoring information is given based on the built bayesian dynamic model; thirdly structural reliability indices are predicted based on the monitoring information and the built bayesian dynamic models; finally an actual example is provided to illustrate the feasibility and application of the built bayesian dynamic models in this paper.
Fabrication and Microstructure of HA Containing Composite Coating on AZ91 Biomedical Magnesium by Plasma Electrolytic Oxidation
Authors: Wang Miao , Wang Yun Long
Published: September 2013

Composite coating containing HA was fabricated on AZ91 biomedical magnesium alloy by plasma electrolytic oxidation in aluminate electrolyte with HA power in electrolyte. The microstructure of the coating including phase composition and surface morphology was investigated. The results showed that the coating consisted of MgO and MgAl2O4and some HA. The whole coating surface was covered by many micro-pores but the surface are relatively uniform. The diameters of most pores were below 5um, and a few pores were bigger than 10 um.
Synthesis of 5-Cyano-3-(4-Chlorobutanoyl) Indole in 1-Buty-3-Methylimidazolium Chloroaluminate
Authors: Jiang Yun Xia , Zuo Hu Jin , Shen Yong Jia , Yi Feng Ping
Published: September 2013

The Friedel-Crafts acylation reaction between 5-cyanoindole and 4-chlorobutyryl chloride was conducted in ionic liquid 1-buty-3-methylimidazolium chloroaluminate ([bmiCl/AlCl3), the major product was 5-cyano-3-(4-chlorobuty) indole. The structure of the product was characterized by Mass and1H NMR spectra. When the molar ratio of AlCl3to [bmiCl in [bmiCl/AlCl3is at 1:1 or less, no 5-cyano-3-(4-chlorobuty) indole could be obtained. The suitable molar ratios of AlCl3to [bmiCl in [bmiCl/AlCl3were from 2:1 to 3:1, the yields of the major product were from 68% to 70%, respectively. When the molar ratio of [bmiCl/AlCl3to 5-cyanoindole was less than 2:1, the acylation reaction was difficult to carry out, because 5-cyanoindole would be not totally dissolve in [bmiCl/AlCl3under the situation.
Study on Hydraulicity and Alkali Activation of Ferroalloy Slag
Authors: Du Bao Li , Fu Xing Hua , Tao Wen Hong , Jin Xin
Published: September 2013

The paper studied that the activity, hydraulicity and Alkali Activation of ferroalloy slag compared to granulated ground blast furnace slag, and a further discussion was carried on ferroalloy slag used as addition of cement. The result shows that the activity index meet national standard and has a well Hydraulicity. Moreover,Ca(OH)2 has a great activition to ferroalloy slag.
The Experimental Study on Consolidation of Acrylic Non-Aqueous Dispersion for Wet-Area Earthen Ruins in Southwest China
Authors: Wu Yi
Published: September 2013

It is a worldwide difficulty to preserve earth monument in wet area. To solve this problem, professor Zhou Shuanglin, an expert of earth monument preserving with College of Archaeology and Museum, Peking University, developed a consolidation agent named acrylic non-aqueous dispersion. But the study on this consolidation agent is still in its initial stage at present for most of its experimental researches are limited to northwest china and no research reports aimed at wet area in southwest China were found so far. To check out the efficiency of this consolidation agent in wet area, southwest China, a consolidating experiment was conducted by applying this consolidation agent to soil samples from kiln Qionglai earthen monuments located in outskirt of Chengdu city, the capital of Sichuan province. In this experiment, the changes of weight, permeating speed and short-term water resistance of specimens after consolidating were investigated and compared with those for northwest area. The study shows that acrylic non-aqueous dispersion consolidation agent developed by professor Zhou Shuanglin is also effective to a certain degree for the earth monument in wet area, southwest China.
The Research and Development of High Strength Spring Steel with Long Service Life
Authors: Xiao Bo , Lei Yu Cheng , Wu Xiao Dong
Published: September 2013

The research centers on the production process of high tensile 60Si2CrVNb spring steel for long service life with reference to the production conditions. Key points of the research lies in: long fatigue life and control techniques of non-metallic inclusions in melting process. Hot treatment process of spring steel also involves with the research, aiming to increase the strength of material by fining grain size by Nb element. The results confirms to the size of non-metallic inclusions can be controlled below 10μm with adoption of technologies of LF slag control and barium microalloy treatment in steelmaking process. The tensile strength can be over 2.0GPa and the elongation can reach up to 10% in the event that the quenching temperature is900°C and the tempering temperature is 410°C resulting obvious increase of strength and plasticity of spring steel.
Nanocrystalline Microstructure in AZ91 Magnesium Alloy Prepared with Cryogenic Treatment
Authors: Li Gui Rong , Wang Hong Ming , Cai Yun , Zhao Yu Tao , Wang Jun Jie , Gu Kai Xuan , Zhang Hong
Published: September 2013

In order to make clear about the effect of cryogenic temperature on the microstructure evolution of alloy, the as-cast AZ91 magnesium alloy was subjected to the cryogenic treatment after solution treatment (415°C,5h) and aging treatment (190°C, 16h) with the protection of graphite power. Transmission Electron Microscope was utilized to characterize the microstructure of as-treated sample. The results show that a high volume fraction of nanocrystalline can be found in the treated alloys with the average sizes are about 55nm. The phenomenon highlights the importance of cryogenic temperature in forming nanostructures. During the continuous contraction of alloy the micro dynamic plastic deformation induces the generation, movement and accumulation of high-density dislocations that give rise to the formation of nanocrystalline during recovery and recrystallization.
Dislocation Character and Evolution Mechanism of Particles Reinforced Aluminum Matrix Composites Impacted by Pulsed Electromagnetic Field
Authors: Yuan Xue Ting , Li Guirong , Wang Hong Ming , Cai Yun , Zhao Yu Tao , Zhang Xun Yin
Published: September 2013

Under the condition of different magnetic induced intensity as1.5T, 2.0T and2.5T, AlTiZr particles reinforced 7055 aluminum matrix composites were subject to the magnetic impact processing. The structural evolution was observed by transmission electron microscope. The result shows that, magnetic impact processing can induce dislocation with different morphologies and increase the dislocation density. The enhancement of dislocation density and elastic interaction between them can cause the resistance of dislocation movement and improve the strength of material. The magnetic pressure may exceed the yield strength of special orientation crystal. The increased temperature induced by heat effect will lower the yield point further. It is useful to dislocation nucleation and movement.
Effect of Impulse Voltage on Microstructure and Corrosion Resistance of Microarc Oxidation Coatings on AZ80 Magnesium Alloy
Authors: Ma Jie , Yang Yuan Sheng , Wang Xiu Chun , Zhang Jing , Liu Shuo , Yi Xi Bin
Published: September 2013

Microarc oxidation coating and microarc oxidation-fluorocarbon coating were prepared on the surface of AZ80 magnesium alloy profiles. The phase structure, surface morphology and corrosion resistance of the coatings were investigated using SEM, XRD, copper sulfate spot test and polarization curve test. The main phase compositions of the microarc oxidation coatings were MgO, Mg2SiO4, MgSiO3, MgF2 and MgAl2O4. With increasing pulse voltage, the oxidation coating became thicker and the microstructure of the coating surface became compact; therefore the coating corrosion resistance was improved. The oxidation coating with pulse voltage of microarc oxidation controlled between 300-438V obtained the best corrosion resistance. The corrosion current density of magnesium alloy reduced 1-3 orders of magnitude after microarc oxidation treatment with increasing pulse voltage, and the corrosion resistance of microarc oxidation-fluorocarbon coating is desirable.
Discussion on Applicability of the Technology of Using Light to Trap in the Field of Pests and Diseases Control in Tea Plantation of China
Authors: Liu Yan , Liu Chang , Zhang Jing Chao , Zhao Shu Ying
Published: September 2013

The quality and safety of agricultural products is a concern for the entire world. The main focus is pesticide residues, which is especially typical in process of tea production. The technology of Using Light to Trap is the best way to solve the problem, because it is to induce and kill pests with physical means of light, electricity, color and etc. Over the past decade, pilot demonstration and applications of insecticidal lamps applied in tea plantation have been conducted in more than a dozen provinces all over China, which achieved remarkable results. This article aims to conduct the work of conclusion and analysis on the basis of test results from fields over the years and the work of comprehensive analysis and accession with the consideration of current development status of the technology of Using Light to Trap, and thus provides scientific basis for ecological control of pests and diseases in tea plantation, reduction on volume of chemical pesticides, decrease of pesticide residues in tea, maintenance of ecological balance and protection for agricultural ecological environment.
Effect of Si3N4 on Properties of Aluminum Borate Whisker/Aluminum Phosphates Ceramic
Authors: Hu Zhen Shi , Geng Hao Ran , Hou Xian Qin , Leng Jin Feng
Published: September 2013

Aluminum Borate Whisker/Aluminum Phosphates composites (ABW/AP) added Si3N4were prepared with pressure sintering technique. The influence of Si3N4on the mechanical properties and dielectric properties were investigated. After sintered at 1050°C for 1h, the results showed that the flexural strength of the composites with 5wt% Si3N4addition reach 167.29MPa,the dielectric constant (ε) and loss tangent (tanδ) of the composites are 2.99 and 0.0089 at 10GHz. The testing results was discussed.
Linear and Non-Linear Optical Phenomena of Glasses (Photonics-Photo Chromic-Electro and Magneto Optics): A Review
Authors: El Sayed Said Yousef
Published: September 2013

The linear and non-linear properties of material have gained in both scientific interest and technological importance. Over the last few years, there has been much interest in developing materials with large nonlinearities in order to exploit their potential for use in ultrafast nonlinear optical devices. The different factors that play a role for controlling the refractive indices such as density, molar refraction, photon energy, coordination number, electronic polarizability, field strength of cations, bridging and nonbridging oxygen, and optical basicity are discussed in accordance with the obtained linear refractive index data. The nonlinear phenomena which include intensity dependent on refractive index, excitation energy, dispersion energy, optical energy, metallization criterion, second and third harmonic generations have been discussed. Finally, the optical application, viz. photonics, electro-optics, photo chromic and magneto-optics of the material have been studied.Keywords:Glass; linear; nonlinear indices; optical application
Guided Bone Regeneration Using Glass-Reinforced Hydroxyapatite and Collagen Membrane in the Treatment of Peri-Implantitis
Authors: Pavan Kumar G. , Naga Sowmya B. , Sooraj Hussain Nandyala , Lopes M.A. , Santos José Domingos
Published: September 2013

Implant therapy has provided the clinician a wide variety of treatment options with respect to the replacement of missing natural teeth. With more number of dentists practicing implant dentistry, one is likely to be presented with peri-implantitis and implant related failures in day to day practice. Peri-impant mucositis can be reversed by elimination of the biofilm but peri-implantitis which results in bone loss and subsequent exfoliation of the implant if left unattended have to be treated using a regenerative approach in addition to conventional non surgical therapy. The present case demonstrates the guided bone regeneration procedure using a glass-reinforced HA and collagen membrane in the treatment of an intrabony defect around the implant. Nine months post operative radiograph revealed complete resolution of the defect. This novel composite alloplast shows promise in treating such lesions.Keywords: Peri-implantitis, Guided bone regeneration, Alloplast, Dental implant, Bone graft, Collagen membrane, Implant decontamination.
Determination of Emissivity Characteristics for Controlled Cooling of Nickel-Alloy Forgings
Authors: Skubisz Piotr , Micek Piotr
Published: September 2013

The paper presents the methodology and the results of determination of emissivity coefficient for nickel alloy Inconel 718 in the temperature range predicted for thermomechanical processing of these alloys and its application for correction of temperature during cooling and modeling. The idea presented in the paper is an iterative use of automatic system of temperature measurement and control, facilitated with thermocouples and pyrometer gauge to provide temperature dependent characteristics of the alloy.
In addition to estimation of temperature dependence of the emissivity coefficient, the results of cooling tests for simple and complex geometry of nickel alloy forgings are contained, obtained with modeling based on assumption of the determined characteristics. To verify obtained characteristic, they were used in modeling of cooling and compared to those obtained in measurements based on assumption of constant value of emissivity coefficient. Measurement errors obtained were used to indicate show the significance of application of functional dependence in comparison with constant value, as well as, magnitude of error made during temperature measurement or modeling, when neglecting the temperature dependence.
Interval Type-2 Fuzzy Logic Control of DM Series Shape Memory Actuator
Authors: Dominik Ireneusz
Published: September 2013

In the article implementation of type-2 fuzzy controller in a microprocessor Arduino is described. The interval type-2 fuzzy sets were used to shorten the cycle time of the algorithm. The type-2 fuzzy logic controller was tested experimentally by controlling position of the shape memory alloy actuator DM series produced by Miga Motor company, the worldwide leader in the field of shape memory alloys applications. The actuator despite small size distinguishes itself by its strength. The obtained results confirmed that type-2 fuzzy controller performed efficiently with difficult to control nonlinear plant. The implemented algorithm can handle uncertainties without increasing drastically the computational complexity. To reduce the response time of the control system an additional accelerating pulse was added to the algorithm.
Shape Prediction of Non-Ferrous Pipe Elements Processed by Electro-Dynamic Forming
Authors: Kot Andrzej
Published: September 2013

The article presents analytical and calculation process of shape prediction of pipe elements formed by electrodynamic forming. In the first part of the work formulation of physical phenomena arising during this method of metal forming is presented. Next, basing at developed mathematical model, with use of numerical methods prediction of the final shape of the semi-finished product during free forming was performed. Results of this stage of tests were compared with results of measurements made during experimental test.
The Analysis of the Different Frequencies Sound Waves Effect on the EEG Signal
Authors: Nawrocka Agata , Holewa Karolina
Published: September 2013

The aim of the experiment was to study the brain's response to the sound stimuli at a specific frequency. The relation between the specific sounds and the changes in the electrical activity of the brain, caused by it, may be helpful to develop the treatment methods of the various disorders of the brain, using the sounds. The aim of the experiment described in the article is to determine the changes in the signal spectrum during the sounds performance with different parameters and to relate it to the basic rhythms, occurring in the EEG signal.
Development of Research Methods for the Assessment of the Technical Condition of Ropes
Authors: Olszyna Grzegorz , Sioma Andrzej , Tytko Andrzej
Published: September 2013

Ropes, including steel wire ropes, are the essential component of the kinematic chains in many passenger and cargo transport systems. Their condition also determines the level of operational safety of those devices. The article is devoted to discussion of methods of assessing the condition of steel wire ropes. The paper discusses magnetic and visual methods. Both methods are used obligatorily to assess ropes employed in rope transport systems. The most significant advantages of the magnetic method and the capabilities of modern methods of analysis of signals obtained from such studies are described. An important part of this article is showing how to determine the geometrical parameters of ropes during a routine evaluation of the degree of wear. The second part of the article presents new methods of determining and recording the geometrical parameters of ropes based on vision systems. The original method of determination of those parameters described herein is complementary to the currently used methods of assessment of the wear of both steel wire ropes and the increasingly more common synthetic fibre ropes. The method is based on the analysis of vision signals. Images of rope surface are created using 3D technology. The article presents some results of research based on which it is possible to identify the geometric dimensions of ropes as well as defects on the surface of those ropes. Such identification is possible on a digital image of a projection of rope surface.
Wave Packet as a Model of Localised Disturbances Propagating along the Cables
Authors: Snamina Jacek
Published: September 2013

In the paper localised disturbances propagating along the cables are modelled by wave packets. The motion of the cable was described in relation to its equilibrium state. The linear equations were used. Typically disturbances associated with sudden gust of wind are modelled by kinematic generator exciting oscillations in the specified frequency range, concentrated around the central frequency. The packet of binormal waves and coupled packets of normal and tangent waves were considered. The description of the evolution of the wave packets during their motion was presented analytically and numerically in the form of plots.
HIV and Tuberculosis co-infection impacts T-cell activation markers but not the numbers subset of regulatory T-cells in HIV-1 infected patients
Authors: Mbow Moustapha , Santos Ndèye S.S. , Camara Makhtar , Ba Awa , Niang Aliou , Daneau Géraldine , Wade Djibril , Diallo Abdou A. , Toupane Maxim , Diakhaté Maïmouna , Lèye Nafissatou , Diaw Papa A. , Mboup Souleymane , Kestens Luc , Dieye Tandakha N.
Published: September 2013

Background: Tuberculosis (TB) has been shown to accelerate the clinical course of HIV infection, but the mechanisms by which this occurs are not well understood. Regulatory T-cells (Tregs)are known to dampen hyperactivation of the immune cells, but it remains unclear whether hyperactivation of T-cells in HIV infection is associated with a decrease of Tregs and what the effect Mycobacterium tuberculosis (MTB) co-infection has on T-cell activation and Tregs.Objectives: In this study, we aim to evaluate whether active TB is associated with the increased expression of T-cell activation markers and reduced number of Treg cells in HIV-1-infected patients.Methods: This study was conducted on 69 subjects consisting of 20 HIV-infected patients,20 HIV and MTB co-infected patients, 19 MTB-infected patients and 10 uninfected control subjects negative for both MTB and HIV. The frequencies of T-cell activation markers (CD38 and HLA-DR) and Treg cells (CD4+CD25+CD127-) were measured by flow cytometry.Results: Significantly higher expression of CD38 and HLA-DR on CD4+ and CD8+ T-cells was found in MTB and HIV co-infected patients compared with HIV-infected patients. However,no significant difference in the percentage of Treg cells was reported between HIV patients with TB and those without. The study also showed a negative correlation between regulatoryT-cells frequency and CD4+ T-cell counts.Conclusion: These results suggest that TB enhances the expression of peripheral T-cell activation markers during HIV infection, whilst having no impact on the percentages of Tregcells.
Towards Transversality of Singular Varieties: Splayed Divisors
Authors: Faber Eleonore
Published: September 2013

We study a natural generalization of transversally intersecting smooth hypersurfaces in a complex manifold: hypersurfaces whose components intersect in a transversal way but may be themselves singular. Such hypersurfaces will be called
splayed
divisors. A splayed divisor is characterized by a property of its Jacobian ideal. This yields an effective test for splayedness. Two further characterizations of a splayed divisor are shown, one reflecting the geometry of the intersection of its components, the other one using K. Saito's logarithmic derivations. As an application we prove that a union of smooth hypersurfaces has normal crossings if and only if it is a free divisor and has a radical Jacobian ideal Further it is shown that the Hilbert–Samuel polynomials of splayed divisors have the natural additivity property.
The Spherical Growth Series for Pure Artin Groups of Dihedral Type
Authors: Fujii Michihiko
Published: September 2013

We consider the kernel of the natural projection from the Artin group of dihedral type

I_2(k)

to the corresponding Coxeter group, which we call the pure Artin group of dihedral type. We present a rational function expression for the spherical growth series of the pure Artin group of dihedral type with respect to a natural generating set.
On special quadratic birational transformations whose base locus has dimension at most three
Authors: Staglianò Giovanni
Published: September 2013

We study birational transformations

\varphi:\mathbb P^n\dashrightarrow\overline{\varphi(\mathbb P^n)}\subseteq\mathbb P^N

defined by linear systems of quadrics whose base locus is smooth and irreducible of dimension

\leq3

and whose image

\overline{\varphi(\mathbb P^n)}

is sufficiently regular.
A note on KAM theory for quasi-linear and fully nonlinear forced KdV
Authors: Baldi Pietro , Berti Massimiliano , Montalto Riccardo
Published: September 2013

We present the recent results in [3] concerning quasi-periodic solutions for quasilinear and fully nonlinear forced perturbations of KdV equations. For Hamiltonian or reversible nonlinearities the solutions are linearly stable. The proofs are based on a combination of di¤erent ideas and techniques: (i) a Nash-Moser iterative scheme in Sobolev scales. (ii) A regularization procedure, which conjugates the linearized operator to a differential operator with constant coeffcients plus a bounded remainder. These transformations are obtained by changes of variables induced by diffeomorphisms of the torus and pseudo-differential operators. (iii) A reducibility KAM scheme, which completes the reduction to constant coefficients of the linearized operator, providing a sharp asymptotic expansion of the perturbed eigenvalues.
A Quaternionic Beltrami-Type Equation and the Existence of Local Homeomorphic Solutions
Authors: Cerejeiras Paula , Gürlebeck Klaus , Kähler Uwe , Malonek H.
Published: September 2013

The paper deals with a quaternionic Beltrami-type equation, which is a very natural generalization of the complex Beltrami equation to higher dimensions. Special attention is paid to the systematic use of the embedding of the set of quaternions

\mathbb H into \mathbb C^2

and the corresponding application of matrix singular integral operators. The proof of the existence of local homeomorphic solutions is based on a necessary and sufficient criterion, which relates the Jacobian determinant of a mapping from

\mathbb R^4

into

\mathbb R^4

to the quaternionic derivative of a monogenic function.
A Sequence of Integro-Differential Equations Approximating a Viscous Porous Medium Equation
Authors: Oelschläger Karl
Published: September 2013

We consider a sequence of particular integro-differential equations, whose solutions

\rho_N

converge as

N \rightarrow \infty

to the solution

\rho

of a viscous porous medium equation. First, it is demonstrated that under suitable regularity conditions the functions

\rho_N

are smooth uniformly in

N \in \mathbb N

. Furthermore, an asymptotic expansion for

\rho_N

as

N \rightarrow \infty

is provided, which precisely describes the convergence to

\rho

. The results of this paper are needed in particular for the numerical simulation of a viscous porous medium equation by a particle method.
Boundary Integral Operators for Plate Bending in Domains with Corners
Authors: Schmidt Gunther
Published: September 2013

The paper studies boundary integral operators of the bi-Laplacian on piecewise smooth curves with corners and describes their mapping properties in the trace spaces of variational solutions of the biharmonic equation. We formulate a direct integral equation method for solving interior and exterior mixed boundary value problems on non-smooth plane domains, analyze the solvability of the corresponding systems of integral equations and prove their strong ellipticity.
The Existence of Non-Trivial Bounded Functionals Implies the Hahn-Banach Extension Theorem
Authors: Luxemburg W.A.J. , Väth Martin
Published: September 2013

We show that it is impossible to prove the existence of a linear (bounded or unbounded) functional on any

L_\infty/C_0

without an uncountable form of the axiom of choice. Moreover, we show that if on each Banach space there exists at least one non-trivial bounded linear functional, then the Hahn-Banach extension theorem must hold. We also discuss relations of non-measurable sets and the Hahn-Banach extension theorem.
Characterization of the Maximal Ideal of Operators Associated to the Tensor Norm Defined by an Orlicz Function
Authors: Loaiza G. , López Molina J. A. , Rivera M. J.
Published: September 2013

Given an Orlicz function

H

satisfying the

\Delta_2

property at zero, one can use the Orlicz sequence space

\mathcal l_H

to define a tensor norm

g^c_H

and the minimal (

H^c

-nuclear) and maximal (

H^c

-integral) operator ideals associated to

g^c_H

in the sense of Defant and Floret. The aim of this paper is to characterize

H^c

-integral operators by a factorization theorem.
Unbounded $C$*-Seminorms and *-Representations of Partial *-Algebras
Authors: Bagarello Fabio , Inoue A. , Trapani Camillo
Published: September 2013

The main purpose of this paper is to construct *-representations from unbounded

C

*-seminorms on partial *-algebras and to investigate their *-representations.
Partial Regularity of Weak Solutions to Nonlinear Elliptic Systems Satisfying a Dini Condition
Authors: Wolf Jörg
Published: September 2013

This paper is concerned with systems of nonlinear partial differential equations

–D_{\alpha}a^{\alpha}_i (x, u, \nabla u) = b_i (x, u, \nabla u) (i = 1,..., N)

where the coefficients

a^{\alpha}_i

are assumed to satisfy the condition

a^{\alpha}_i (x, u, \xi) – a^{\alpha}_i (y, v, \xi) ≤ \omega |x–y| + |u–v| (1+|\xi|)

for all

{x, u}, {y, v} \in \Omega \times \mathbb R^N

and all

\xi \in \mathbb R^{nN}

, and where

\int^1_0 \frac {\omega (t)}{t} dt < + \infty

while the functions

\frac {\partial a_i^{\alpha}}{\partial \xi ^j_{\beta}}

satisfy the standard boundedness and ellipticity conditions and the function

\xi \mapsto b_i (x, u, \xi)

may have quadratic growth. With these assumptions we prove partial Hölder continuity of bounded weak solutions

u

to the above system provided the usual smallness condition on

\|u \|_{L^\infty ({\Omega})}

is fulfilled.
Nonlinear Diffusion Equations on Bounded Fractal Domains
Authors: Hu Jiaxin
Published: September 2013

We investigate nonlinear diffusion equations

\frac {\partial u}{\partial t} = \Delta ¢u +f(u)

with initial data and zero boundary conditions on bounded fractal domains. We show that these equations possess global solutions for suitable

f

and small initial data by employing the iteration scheme and the maximum principle that we establish on the bounded fractals under consideration. The Sobolev-type inequality is the starting point of this work, which holds true on a large class of bounded fractal domains and gives rise to an eigenfunction expansion of the heat kernel.
Hyperbolic Limit of Parabolic Semilinear Heat Equations with Fading Memory
Authors: Pata V.
Published: September 2013

This paper is devoted to the comparison of two models describing heat conduction with memory, arising in the frameworks of Coleman-Gurtin and Gurtin-Pipkin. In particular, the second model entails an equation of hyperbolic type, where the dissipation is carried out by the memory term solely, and can be viewed as the limit of the first model as the coefficient

\omega

of the laplacian of the temperature tends to zero. Results concerning the asymptotic behavior, with emphasis on the existence of a uniform attractor, are provided, uniformly in

\omega

. The attractor of the hyperbolic model is shown to be upper semicontinuous with respect to the family of attractors of the parabolic models, as

\omega

tends to zero.
On $S$-Homogenization of an Optimal Control Problem with Control and State Constraints
Authors: Kogut Peter I. , Leugering Günter
Published: September 2013

We study the limiting behavior of an optimal control problem for a linear elliptic equation subject to control and state constraints. Each constituent of the mathematical description of such an optimal control problem may depend on a small parameter

\epsilon

. We study the limit of this problem when

\epsilon \rightarrow 0

in the framework of variational

S

-convergence which generalizes the concept of

\Gamma

-convergence. We also introduce the notion of

G*

-convergence generalizing the concept of

G

-convergence to operators with constraints. We show convergence of the sequence of optimal control problems and identify its limit. We then apply the theory to an elliptic problem on a perforated domain.
An Interpolation Problem for Hilbert-Schmidt Operator-Valued Stationary Processes
Authors: Klotz L.
Published: September 2013

The paper contains a solution of the following interpolation problem for Hilbert-Schmidt operator-valued stationary processes on the real line: Assume that the values of the process on the integers are known. Determine the best linear approximation of an unknown value on the basis of the known values and compute the approximation error. Our results generalize previous results of Yaglom and Salehi for univariate and

q

-variate processes, respectively.
On Fourier Transforms of Wavelet Packets
Authors: Ahmad K. , Debnath L. , Kumar R.
Published: September 2013

This paper deals with the Fourier transform

\hat{\omega}_n

of wavelet packets

\omega_n \in L^2 (\mathbb R)

relative to the scaling function

\varphi = \omega_0

. Included there are proofs of the following statements:(i)

\hat{\omega}_n (0)

) = 0 for all

n \in \mathbb N

.(ii)

\hat{\omega}_n (4nk\pi) = 0

for all

k \in \mathbb Z, n = 2j

for some

j \in \mathbb N_0

, provided

|\hat{\varphi}|, |m_0|

are continuous.(iii)

|\hat{\omega}_n (\xi)|^2 = \sum^{2^r–1}_{s=0} |\hat{\omega}_{2^r n+s} (2^r \xi)|^2

for

r 2\in \mathbb N

.(iv)

\sum^\infty_{j=1} \sum^{2^r–1}_{s=0} \sum_{k \in \mathbb Z} |\hat{\omega}_n (2^{j+r} (\xi + 2k\pi))|^2 = 1

for a.a.

\xi \in \mathbb R

where

r = 1, 2,...,j

.Moreover, several theorems including a result on quadrature mirror filter are proved by using the Fourier transform of wavelet packets.
Semilinear Hyperbolic Systems with Singular Non-Local Boundary Conditions: Reflection of Singularities and Delta Waves
Authors: Kmit Irina , Hörmann Günther
Published: September 2013

In this paper we study initial-boundary value problems for first-order semilinear hyperbolic systems where the boundary conditions are non-local. We focus on situations involving strong singularities, of the Dirac delta type, in the initial data as well as in the boundary conditions. In such cases we prove an existence and uniqueness result in an algebra of generalized functions. Furthermore, we investigate the existence and structure of delta waves, i.e., distributional limits of solutions to the regularized systems. Due to the additional singularities in the boundary data the search for delta waves requires a delicate splitting of the solution into a linearly evolving singular part and a regular part satisfying a nonlinear equation. A new feature in the splitting procedure used here, compared to delta waves in pure initial value problems, is the dependence of the singular part also on part of the regular part due to singularities enetering from the boundary. Finally, we include simple examples where the existence of delta waves breaks down.
On the Cauchy Problem for a Degenerate Parabolic Equation
Authors: Winkler Michael
Published: September 2013

Existence and uniqueness of global positive solutions to the degenerate parabolic problem

u_t = f(u)\Delta u \ \ \mathrm {in} \ \ \mathbb R^n \times (0, \infty)

u|_{t=0} = u–0

with

f \in C^0 ((0, \infty)) \cap C^1 ((0, \infty))

satisfying

f(0) = 0

and

f(s) > 0

for

s > 0

are investigated. It is proved that, without any further conditions on

f

, decay of

u_0

in space implies uniform zero convergence of

u(t)

as

t \rightarrow \infty

. Furthermore, for a certain class of functions

f

explicit decay rates are established.
Quadratic Forms and Nonlinear Non-Resonant Singular Second Order Boundary Value Problems of Limit Circle Type
Authors: Agarwal R.P. , O'Regan Donal , Lakshmikantham V.
Published: September 2013

New existence results are presented for non-resonant second order singular boundary value problems

\frac {1}{p(t)}(p(t)y'(t))' + \tau (t)y(t) = \lambda f(t,y(t)) \ \ \mathrm {a.e. on \ \ [0,1]}

\mathrm {lim}_{t\to 0^+} p(t)y'(t) = y (1) = 0

where one of the endpoints is regular and the other may be singular or of limit circle type.
The Upper and Lower Functions Method for Second Order Systems
Authors: Lepin A. Ja. , Sadyrbaev Felix Zh.
Published: September 2013

Two-point boundary value problems for

m

-dimensional second order systems are considered. The method of upper and lower functions is applied to problems of the Dirichlet type and problems with nonlinear boundary conditions. The conditions on upper and lower functions are substantially relaxed comparing with the classical

C^2

-class and properties of them are studied for systems with monotone in

x

right sides. Consequences for even order differential equations with mixed monotonicities are given.
Crack Detection in Plane Semilinear Elasticity
Authors: Trong Dang Duc
Published: September 2013

Let ­

\Omega

be a two-dimensional semilinear elastic body limited by a known outer boundary

\Gamma

represented by a Jordan curve and an unknown inner boundary

\gamma

represented by a finite disjoint union of piecewise

C^1

Jordan curves. Plane stress is considered. We assume that the Lamé coefficient depends on the spacial variables

x, y

and the displacements

u, v

. Our main result asserts that

\gamma

is uniquely determined by the displacements and stresses prescribed on an open portion

\Gamma_0

of

\Gamma

.
Linear Combinations of Frames and Frame Packets
Authors: Christensen Ole
Published: September 2013

We find coefficients

c_{mn} (m, n \in \mathbb Z)

such that for an arbitrary frame

\lbrace f_n \rbrace_{n \in \mathbb Z}

the set of vectors

\lbrace \phi_m \rbrace_{m \in \mathbb Z} = \lbrace \sum _{n \in \mathbb Z} c_{mn}f_n \rbrace_{m \in \mathbb Z}

will again be a frame. Appropriate coefficients can always be chosen as function values

c_{mn} = g(\frac {n}{\beta} – m\alpha)

), where

g

belongs to a broad class of functions generating a Gabor frame

\lbrace E_{\beta m} T_{\alpha n}g \rbrace_{m, n \in \mathbb Z}

for

L^2(\mathbb R)

. We also prove a version of the splitting trick, which allows to construct a large family of frames based on a single (wavelet or Gabor) frame.
Automatic Control of the Temperature in Phase Change Problems with Memory
Authors: Gatti S.
Published: September 2013

We study a parabolic two-phase system with memory occupying a bounded and smooth domain. The heat exchange at part of the boundary is controlled by a thermostat. Assuming on the phase variable either a relaxation dynamics or a Stefan condition, we prove existence and uniqueness results for feedback control problems corresponding to two different types of thermostat: the relay switch and the Preisach operator. These results are strictly related to the continuous dependence of the solution on the boundary datum, which is investigated in advance.
Hausdorff Convergence and Asymptotic Estimates of the Spectrum of a Perturbed Operator
Authors: Mel'nyk T.A.
Published: September 2013

A family of self-adjoint compact operators

A_{\epsilon} (\epsilon > 0)

acting in Hilbert spaces

\mathcal H_{\epsilon}

is considered. The asymptotic behaviour as

\epsilon \to 0

of eigenvalues and eigenvectors of the operators

A_{\epsilon}

is studied; the limiting operator

A_0 : \mathcal H_0 \mapsto \mathcal H_0

is non-compact. Asymptotic estimates of the differences between eigenvalues of

A_{\epsilon}

and points of the spectrum

\sigma (A_0)

(both of the discrete spectrum and the essential one) are obtained. Asymptotic estimates for eigenvectors of

A_{\epsilon}

are also proved.
A Priori Gradient Bounds and Local $C^{1, \alpha}$-Estimates for (Double) Obstacle Problems under Non-Standard Growth Conditions
Authors: Bildhauer M. , Fuchs Martin , Mingione Giuseppe
Published: September 2013

We prove local gradient bounds and interior Hölder estimates for the first derivatives of functions

u \in W^1_{1, loc} (\Omega)

which locally minimize the variational integral

I(u) = \int _{\Omega} f (\nabla u) dx

subject to the side condition

\psi _1 ≤ u ≤ \psi_2

. We establish these results for various classes of integrands

f

with non-standard growth. For example, in the case of smooth

f

the

(s, \mu, q)

-condition is sufficient. A second class consists of all convex functions

f

with

(p, q)

-growth.
$L_1$-Norms of Exponential Sums and the Corresponding Additive Problem
Authors: Garaev M.Z. , Kueh Ka-Lam
Published: September 2013

In this note, a new estimate of

L_1

-norm of certain exponential sum is obtained. At the same time, we establish a sharp lower bound for the cardinality of corresponding sumsets. In some cases this lower bound gives the true order of the cardinality.
Iteration Procedures of Shuttle Iteration Type in Continuous Non-Monotone Problems
Authors: Rachinskii D.
Published: September 2013

We suggest and study iteration procedures converging from below and above to robust stable solutions and to robust stable continuous branches of solutions for quasilinear boundary-value problems with continuous non-monotone non-linearities. The iterations are constructed by modifications of the shuttle iteration method, which is used in problems with monotone operators leaving invariant a cone interval.
Existence of Non-Oscillatory Solutions of Second-Order Neutral Delay Difference Equations
Authors: Zhou Yong , Huang Y. Q.
Published: September 2013

In this paper, we consider the second-order neutral delay difference equation with positive and negative coefficients

\Delta r_n \Delta (x_n + cx_{n–k}) + p_{n+1}x_{n+1–m} -q_{n+1}x_{n+1-l}= 0

where

c \in \mathbb R

,

k ≥ 1

and

m, l ≥ 0

are integers,

\lbrace r_n\rbrace^\infty _{n=n_0}, \lbrace p_n\rbrace ^\infty _{n=n_0}

and

\lbrace q_n \rbrace ^\infty _{n=n_0}

are sequences of non-negative real numbers. We obtain global results (with respect to

c

) which are some sufficient conditions for the existences of non-oscillatory solutions.
Tensor Algebras and Displacement Structure I. The Schur Algorithm
Authors: Constantinescu Tiberiu , Johnson J. L.
Published: September 2013

In this paper we explore the connection between tensor algebras and displacement structure. Thus, we describe a scattering experiment in this framework, we obtain a realization of the elements of the tensor algebra as transfer maps of a certain class of non-stationary linear systems, and we describe a Schur type algortihm for the Schur elements of the tensor algebra.
Quaternionic Reformulation of Maxwell Equations for Inhomogeneous Media and New Solutions
Authors: Kravchenko Vladislav V.
Published: September 2013

We propose a simple quaternionic reformulation of Maxwell equations for inhomogeneous media and use it in order to obtain new solutions in a static case.
$L_q-L_r$-Estimates for Non-Stationary Stokes Equations in an Aperture Domain
Authors: Abels Helmut
Published: September 2013

This article deals with asymptotic estimates of strong solutions of Stokes equations in aperture domains. An aperture domain is a domain, which outside a bounded set is identical to two half spaces separated by a wall and connected inside the bounded set by one or more holes in the wall. It is known that the corresponding Stokes operator generates a bounded analytic semigroup in the closed subspace

J_q(\Omega)

of divergence free vector fields of

L_q(\Omega)^n

. We deal with

L_q-L_r

-estimates for the semigroup, which are known for

\mathbb R^n

, the half space and exterior domains.