bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Small Carbon Nanoparticles in a Microwave Plasma Flow Reactor
Authors: Gurentsov Evgeny , Priemchenko Konstantin , Grimm Helge , Orthner Hans , Wiggers Hartmut , Borchers Christine , Jander Helga , Eremin Alexander , Schulz Christof
Published: March 2013

Unusually small carbon nanoparticles were synthesized in a microwave plasma flow-reactor by pyrolysis of 0.3–1.2% CH4, C2H4, and C2H2 with 0.3–3.6% addition of molecular hydrogen in argon. Final particle sizes were analyzed by in-line particle-mass spectrometry (PMS) and by transmission electron microscopy (TEM). TEM measurements of primary particle sizes were found to be in a good agreement with PMS data. The carbon particles formed in the plasma generated by a 2.45 GHz magnetron with an applied power of 180 W and a total pressure of 13 mbar have diameters of 4–6 nm. The type of hydrocarbon precursor and 0.3–3.6% of hydrogen addition did not noticeably influence the final particle sizes. The formation of such small particles is attributed to the low pressure and the comparably low operation power. This method of small carbon nanoparticles synthesis could be useful for the production of carbon black material, where large surface area is important.
Effect of Temperature on the Supramolecular Behavior of Antidepressant Drug Amitriptyline Hydrochloride in the Presence of Nonionic Surfactants (Tweens and Brijs) as Pharmaceutical Excipients
Authors: Yaseen Zahid , Aslam Jeenat , Dar Aijaz Ahmad , ud - Din Kabir -
Published: March 2013

The aggregational and adsorption behavior of an important antidepressant amphiphilic drug amitriptyline hydrochloride have been studied in the presence of nonionic surfactants at different temperatures by tensiometry. By using regular solution theory and other thermodynamic models, different physicochemical properties such as critical micellar concentration, micellar composition, interfacial adsorption, energetic parameters (free energy, enthalpy, entropy) of micellization are evaluated. The data clearly depict that there is strong interaction between the amitriptyline hydrochloride and nonionic surfactants. Steric factor appears to play an important role during interaction when surfactant molecular structure varies in size of the head group and chain length of the hydrophobic part. The temperature has been observed to be vital in controlling the dehydration and thermal solubility which, in turn, makes environment conducive for aggregational behavior of the drug-surfactant mixtures in aqueous solution.
Persuasive Ethopoeia in Dionysius's Lysias
Authors: Bruss Kristine S.
Published: March 2013

Dionysius of Halicarnassus's account of ethopoeia at Lysias 8 is often cited as evidence of Lysias mastery of character portrayal, but the passage itself has received little in-depth analysis. As a consequence, Dionysius's meaning has at times been misinterpreted, and some of his insights on characterization have been neglected. When the account is examined closely, three unique points of emphasis emerge which, taken together, constitute a particular type of characterization: persuasive, as opposed to propriety-oriented, ethopoeia. Making this distinction promotes conceptual clarity with regard to ethopoeia while calling attention to Dionysius's insights on the role of style and composition in the creation of persuasive ethos.
Atrial fibrillation and physical activity
Authors: Apor Péter
Published: March 2013

Atrial fibrillation is the most frequent arrhythmia. Its „lone” form (when underlying pathology is not discovered) can be detected in a few percent of endurance sports participants, and in growing occurrence among the veterans, probably on the basis of some cardiac or other irregularities. Enhanced vagal tone and sudden sympathetic impulse, repetitive oxidative stress, inflammatory processes, enlarged atria, electric instabilization can explain the higher occurrence. Treatment of atrial fibrillation enables the affected persons to participate in regular medium-intensity exercise, 3–5 hours a week, which offers a protective role against cardiovascular, metabolic and mental illnesses. Orv. Hetil., 2013, 154, 503–509.
Thin Film Calorimetry - Device Development and Application to Lithium Ion Battery Materials
Authors: Wulfmeier Hendrik , Albrecht Daniel , Ivanov Svetlozar , Fischer Julian , Grieseler Rolf , Schaaf Peter , Ulrich Sven , Bund Andreas , Fritze Holger
Published: March 2013

The work takes advantage of a newly developed measurement system which enables to investigate the thermodynamic properties of thin films including battery layer sequences. This technique, Thin-Film Calorimetry (TFC), is based on the detection of resonance frequency shifts of bulk acoustic wave resonators. Thin films with a thickness of several micrometers of the material of interest are deposited on the resonators. By measuring the temperature dependent shift of the resonance frequency, the device is working as a precise temperature sensor. The production or consumption of latent heat by the active layer(s) results in temperature fluctuations with respect to the furnace where the sensor is placed. Those information enable to extract the temperature and time dependence of phase transformations as well as the associated enthalpies. To cover a temperature range from -20 to 900 °C high-temperature stable piezoelectric resonators made of langasite crystals (La3Ga5SiO14) are applied.

Initially, metallic layers of tin and aluminum are used to test and verify this approach. The temperatures and enthalpies of solid-liquid as well as of solid-solid phase transformation are observed in the correct manner. Further, the thermodynamic data of the battery materials Li(Ni0.8Co0.15Al0.05)O2-δ (NCA) and LiMn2O4-δ (LMO) obtained by TFC are determined and discussed. Both cathode materials are amorphous after deposition and show crystallization during heating at 460 °C (NCA) and 600 °C (LMO). The associated enthalpies are 5.3 kJ/mol (55 J/g) and 17.3 kJ/mol (96 J/g), respectively.
Electrochemical properties of all-solid-state lithium secondary batteries using Li-argyrodite Li6PS5Cl as solid electrolyte
Authors: Boulineau Sylvain , Tarascon Jean-Marie , Seznec Vincent , Viallet Virginie
Published: March 2013

Highly ion-conductive Li6PS5Cl Li-argyrodites were prepared through a high energy ball milling. Electrical and electrochemical properties were investigated. Ball-milled compounds exhibit a high conductivity of 1.33×10−4S/cm with an activation energy of 0.3-0.4 eV and an electrochemical stability up to 7V vs. lithium. These results are obtained after only 10 hours of milling and with no additional heat treatment.

To validate the use of the Li6PS5Cl-based solid electrolyte, all-solid-state batteries using LiCoO2and Li4Ti5O12as active material have been realized. The optimization of the electrode composition led to a maximum of 46 and 27 mAh per gram of composite for LiCoO2and Li4Ti5O12-based half-cells respectively. The assembled all-solid-state LiCoO2/ Li6PS5Cl / Li4Ti5O12battery presents a sustainable reversible capacity of 27 mAh per gram of active material and a coulomb efficiency close to 99%.
Qualidade de vida dos indivíduos expostos ao césio-137, em Goiânia, Goiás, Brasil
Authors: Fuini Silvana Cruz , Souto Rafael , Amaral Geraldo Francisco do , Amaral Rita Goreti
Published: March 2013

Estudo observacional transversal realizado em Goiânia, Goiás, Brasil, em uma amostra de 56% de 111 pessoas, objetivando avaliar a qualidade de vida dos indivíduos expostos ao césio-137 e sua associação com fatores sociodemográficos. Utilizou-se o WHOQOL-BREF e o Sistema de Monitoramento dos Radioacidentados. Os participantes foram divididos segundo critérios internacionais em: Grupo I - radiodermites e/ou dosimetria citogenética acima de 20 rads (n = 33); e Grupo II - dosimetria citogenética ≤ 20 rads (n = 29), totalizando 62 sujeitos. Dentre os domínios do WHOQOL-BREF, o meio ambiente apresentou a média de escores mais alta (59,88; DP = 20,39) e o psicológico a média mais baixa (53,02; DP = 17,98). As associações entre os domínios físico, psicológico e relações sociais foram significativas para a variável idade. Não houve diferença entre grupos. A associação entre os fatores sociodemográficos e qualidade de vida não foi significativa. Os radioacidentados sofrem considerável impacto na qualidade de vida, com persistência de problemas psicossociais, especialmente para aqueles com mais de 41 anos.
Validade dimensional do instrumento de qualidade de vida WHOQOL-BREF aplicado a trabalhadores de saúde
Authors: Castro Marcelle Maria Lobo Dinis , Hökerberg Yara Hahr Marques , Passos Sonia Regina Lambert
Published: March 2013

O objetivo foi reavaliar a estrutura dimensional da versão brasileira do WHOQOL-BREF, consistência interna e validade fatorial convergente e discriminante. Estudo seccional em 386 trabalhadores de saúde. A análise fatorial confirmatória testou a estrutura do WHOQOL-BREF (24 e 26 itens) e a sugerida pela análise fatorial exploratória. Consistência interna foi aferida via confiabilidade composta; validade convergente e discriminante, pela variância média extraída e correlação entre fatores. O modelo de melhor ajuste foi o sugerido pela análise fatorial exploratória (26 itens) com seis fatores: quatro propostos teoricamente (geral, psicológico, relações sociais e meio ambiente) e dois pela subdivisão do domínio físico. Os itens "energia" e "segurança" (respectivamente, do físico e meio ambiente) foram remanejados para o psicológico. A confiabilidade composta foi boa (> 0,70), à exceção do fator geral. Validade convergente e discriminante foram adequadas para relações sociais e físico 2. Persistem controvérsias sobre a dimensionalidade do WHOQOL-BREF, particularmente sobre o domínio físico.
Rede FIBRA-RJ: fragilidade e risco de hospitalização em idosos da cidade do Rio de Janeiro, Brasil
Authors: Perez Mariangela , Lourenço Roberto Alves
Published: March 2013

O objetivo do estudo foi determinar o perfil de risco e fatores associados à fragilidade em idosos da comunidade. A população-fonte constituiu-se de indivíduos com 65 anos ou mais, residentes nos bairros da zona norte da cidade do Rio de Janeiro, Brasil, e clientes de uma operadora de saúde. O estudo foi transversal, na linha de base de uma coorte, com amostra estratificada por sexo e idade, composta por 764 indivíduos. Para a estratificação de risco, utilizou-se o instrumento de rastreio probabilidade de internações repetidas (PIR). A análise de regressão logística foi realizada para estudar a associação entre a PIR e um conjunto de variáveis sociodemográficas, de estado de saúde, funcionais e cognitivas, após a análise bivariada. Encontraram-se 6,7% de idosos com alto risco de internação. Associaram-se ao risco de internação câncer, quedas, doença pulmonar obstrutiva crônica e medicamentos usados, bem como as seguintes condições: receber visita de profissional da saúde, ter estado acamado no domicílio, morar só e praticar as atividades de vida diária. O instrumento parece ser útil na estratificação de risco dos idosos.
Factors associated with alcohol intake and alcohol abuse among women in Belo Horizonte, Minas Gerais State, Brazil
Authors: Machado Ísis Eloah , Lana Francisco Carlos Félix , Felisbino-Mendes Mariana Santos , Malta Deborah Carvalho
Published: March 2013

The main objective of this cross-sectional study was to analyze factors associated with alcohol consumption among adult women living in Belo Horizonte, Minas Gerais State, Brazil, in 2011. Data for Belo Horizonte were obtained from the VIGITEL system (Telephone-Based Surveillance of Risk and Protective Factors for Chronic Diseases). Alcohol use was defined as self-reported intake of at least one dose in the previous 30 days; alcohol abuse was defined as four or more doses on at least one occasion during the same period. Polytomous logistic regression was used to evaluate factors associated with alcohol use and abuse. Alcohol use was more prevalent among women 25 to 34 years of age. Alcohol abuse was associated with age, schooling, health status, and smoking. The results suggest the need for policies to prevent alcohol abuse among women, especially targeting those who are younger, single, smokers, and with more education.
Estudo da mortalidade dos médicos no Estado de São Paulo, Brasil, no período 2000-2009
Authors: Sanchez Zila M. , Alves Hamer N. Palhares , Nogueira-Martins Luiz Antônio , Prado Mariangela C. Oliveira
Published: March 2013

O presente estudo apresenta a distribuição das causas de morte de médicos do Estado de São Paulo, Brasil, cujos óbitos ocorreram entre os anos de 2000 e 2009. Utilizou-se o banco de dados do Sistema de Informações sobre Mortalidade, do Ministério da Saúde, limitando-se às declarações de óbito cujo campo de ocupação estava preenchido como "médico". As causas básicas de morte foram classificadas de acordo com os capítulos da CID-10. O estudo revela que doenças do aparelho circulatório foram a principal causa de morte entre os médicos na última década, seguidas das neoplasias e doenças do aparelho respiratório. As causas externas constituíram as principais causas de morte abaixo de 40 anos. Câncer da mama foi responsável pela maior parte dos óbitos por neoplasias entre mulheres, enquanto entre os homens a neoplasia de pulmão ocupou a primeira posição. Sugere-se a necessidade de se estimular hábitos adequados de saúde e prevenção de doenças entre os médicos, buscando informar e sensibilizar este grupo de profissionais.
A suitable methodology for assessing impacts of successive rainfalls infiltration on road slope stability
Authors: Rameau Hugues Georges , Prepetit Claude , Verbrugge Jean-Claude
Published: March 2013

Water precipitation in road slopes, pavements, and shoulders may cause disturbances such as erosion, increase of the water table level, decrease of the carriageway bearing capacity, and so on. Roads are normally equiped with drainage systems that are sized and implemented in accordance with the rules of art. These equipments are used for the collection and quick evacuation of water precipitation estimated on the basis of the return period that is taken into account. Despite that, rainwater can still infiltrate unprotected cut or fill slopes, and pavements for repeated and intense rainfalls, which may cause a raise in pore-water pressure and a decrease of the factor of safety of road slopes. Using laboratory rainfall simulation techniques, infiltration measurements were made on intact samples to determine with respect to soil properties, how cumulative rainfalls cause decrease in apparent cohesion and lead to slope failure. This paper focuses on describing the relationship between the rainfall characteristics, the changes in soil water profile, and the changes in apparent cohesion for sandy clay samples collected on the national road RN3 located in Haiti. For a set of consecutive rainfall events at around an interval of 24 hours, the results prove that when wetting front depth approaches 2 meters or more, the risk of landslide is proportionally high in a soil with apparent cohesion (Ca) initially high and an effective cohesion (c′) relatively low.
Seismic anisotropy beneath the northeastern Caribbean: implications for the subducting North American lithosphere
Authors: Meighan Hallie E. , Pulliam Jay
Published: March 2013

Active plate boundaries in the Caribbean form a complex tectonic environment that includes transform and subduction zones. The Caribbean-North American plate boundary is one such active margin, where subduction transitions from arc- to oblique-type off the northeast coast of Puerto Rico. Understanding mantle flow in this region will not only help determine the nature of tectonic activity and mantle dynamics that control these margins, but will also aid our understanding of the fate of subducting lithosphere.

The existence of tears, windows, and gaps in subducting slabs has been proposed at various locations around the world but few have been confirmed. Since mantle flow and crustal deformation are believed to produce seismic anisotropy in the asthenosphere and lithosphere, searching for changes in, for example, SKS splitting parameters can help identify locations at which subducting slabs have been disrupted.

Several lines of evidence support the notion of a slab tear within the subducting North American plate at this transition zone, including the counter-clockwise rotation of the Puerto Rico microplate over the past ~10 Ma, clusters of small seismic events, and trench collapse initiating ~3.3 m.y. Here we present results from a detailed investigation of seismic anisotropy from 28 stations across six networks in the Northeast Caribbean that support the hypothesis of a significant slab gap in the vicinity of the U.S. and British Virgin islands.

A regional synthesis of our results reveals fast shear wave polarizations that are generally oriented parallel to the plate boundary with intermediate to high SH-SV delay times. For example, polarization directions are oriented roughly NE-SW along the bulk of the Lesser Antilles, E-W along the Puerto Rico trench and the northern Lesser Antilles, and NW-SE beneath Hispaniola. Beneath the U.S. and British Virgin Islands, however, the fast polarization direction differs markedly from the regional pattern, becoming almost perpendicular to the plate boundary. Stations on Anegada, British Virgin islands and St. Croix, U.S. Virgin islands show a fast polarization direction that is oriented nearly NNE-SSW and smaller delay times than surrounding stations. These results suggest that mantle flow is redirected NE-SW at this location through a gap in the subducted lithosphere of the North American plate.
Manipulation of atom-to-molecule conversion in a magnetic lattice
Authors: Hui Ning-Ju , Lu Li-Hua , Fu Li-Bin , Li You-Quan
Published: March 2013

Atom-to-molecule conversion by the technique of optical Feshbach resonance in a magnetic lattice is studied in the mean-field approximation. For the case of a shallow lattice, we give the dependence of the atomto-molecule conversion efficiency on tunnelling strength and atomic interaction by taking a double-well as an example. We find that one can obtain a high atom-to-molecule conversion by tuning the tunnelling and interaction strengths of the system. For the case of a deep lattice, we show that the existence of the lattice can improve the atom-to-molecule conversion for certain initial states.
Analysis of two colliding fractionally damped spherical shells in modelling blunt human head impacts
Authors: Rossikhin Yury , Shitikova Marina
Published: March 2013

The collision of two elastic or viscoelastic spherical shells is investigated as a model for the dynamic response of a human head impacted by another head or by some spherical object. Determination of the impact force that is actually being transmitted to bone will require the model for the shock interaction of the impactor and human head. This model is indended to be used in simulating crash scenarios in frontal impacts, and provide an effective tool to estimate the severity of effect on the human head and to estimate brain injury risks. The model developed here suggests that after the moment of impact quasi-longitudinal and quasi-transverse shock waves are generated, which then propagate along the spherical shells. The solution behind the wave fronts is constructed with the help of the theory of discontinuities. It is assumed that the viscoelastic features of the shells are exhibited only in the contact domain, while the remaining parts retain their elastic properties. In this case, the contact spot is assumed to be a plane disk with constant radius, and the viscoelastic features of the shells are described by the fractional derivative standard linear solid model. In the case under consideration, the governing differential equations are solved analytically by the Laplace transform technique. It is shown that the fractional parameter of the fractional derivative model plays very important role, since its variation allows one to take into account the age-related changes in the mechanical properties of bone.
Acting in the New World: Studio and Location Realism in Survivors
Authors: Hewett Richard
Published: March 2013

While the development of British television drama has been well charted, comparatively little work has been conducted with regard to the medium's impact on acting style. This article is intended to address that lack, evolving a framework of ‘studio realism’ and ‘location realism’ to examine how changes in production can affect acting in television drama, using the BBC series Survivors (1975–7) as a case study. Originally produced along the traditional Corporation lines of filmed location work followed by rehearsal at the purpose-built Acton rooms (typically two weeks for a 50-minute episode of drama) and two days of studio recording at Television Centre, after its initial seven episodes the programme switched to an all-location model using Outside Broadcast video cameras. Instead of preparing in a separate space, the cast adopted an on-location rehearse/record process, a template that has endured, with certain modifications, to the present day. By employing a combination of original cast interviews and textual analysis, I examine what effects this altered mode of production had on acting, as pre-planned, ‘in continuity’, multi-camera studio work – itself a remnant of the live process imported from the stage in the 1930s – began to give way to the out-of-sequence, single-camera model – in which performances are evolved almost entirely on site – which predominates today. In this way the conditions and effects of studio and location realism are exemplified and investigated in an attempt to make an opening contribution to the hitherto largely neglected field of acting for television drama.
Selective surface modification of lithographic silicon oxide nanostructures by organofunctional silanes
Authors: Baumgärtel Thomas , von Borczyskowski Christian , Graaf Harald
Published: March 2013

This study investigates the controlled chemical functionalization of silicon oxide nanostructures prepared by AFM-anodization lithography of alkyl-terminated silicon. Different conditions for the growth of covalently bound mono-, multi- or submonolayers of distinctively functional silane molecules on nanostructures have been identified by AFM-height investigations. Routes for the preparation of methyl- or amino-terminated structures or silicon surfaces are presented and discussed. The formation of silane monolayers on nanoscopic silicon oxide nanostructures was found to be much more sensitive towards ambient humidity than, e.g., the silanization of larger OH-terminated silica surfaces. Amino-functionalized nanostructures have been successfully modified by the covalent binding of functional fluorescein dye molecules. Upon excitation, the dye-functionalized structures show only weak fluorescence, which may be an indication of a relatively low surface coverage of the dye molecules on length scale that is not accessible by standard AFM measurements.
Modeling of Titanium Oxide Layer Growth Produced by Fiber Laser Beam
Authors: Hamadi Farida , Amara El Hachemi , Bennaceur-Doumaz Djamila , Boutaka R. , Kellou H. , Bourai Kamel , Noukaz A. , Beggar R.
Published: March 2013

In this paper, we study the oxidation process during the heating of a titanium metallic surface by a Nd-YAG fiber pulsed laser beam under air environment. For this, we adopted an approach that considers a three-dimensional heat diffusion model coupled with an oxidation parabolic law (oxidation kinetics). The heat diffusion equation solved numerically, gives the temperature field. The oxide film growth is simulated by implementing a dynamic mesh technique. We developed computational procedures UDFs (User Defined Function) running interactively with the Fluent fluid dynamics software [ that implements the finite volume method. These UDFs are developed to insert the oxidation law, the temperature field, the specific boundary conditions and the mesh deformation into the calculation.
Sensitivity of Models Applied in Selected Simulation Systems with Respect to Database Quality for Resolving of Casting Problems
Authors: Ignaszak Zenon , Popielarski Paweł , Hajkowski Jakub
Published: March 2013

This paper highlights permanent development of process virtualization in the mechanical engineering industry, especially in the area of foundry. Virtualization is increasingly developed on the stage of product design and materials technologies optimization. Simultaneously, increasing expectations of design and process engineers regarding the practical effectiveness of applied simulation systems is observed. To enhance the knowledge in the scope of modelling and simulation in the foundry processes, one should be acquainted with the hard modelling based on physical-mathematical formula and also the soft modelling, burdened with simplifications resulting from both knowledge level on description of particular phenomena and level of theirs complexity. The trends observed in modelling of foundry processes and expectations of users compared with creators upgraded propositions new, additional modules based mostly on poorly tested theory are discussed. In such cases, each new module should be tested on sensitivity of additional parameters, which appear in these new modules. If needed and possible, these tests ought to be related to validation of the whole complex model containing such new modules. The purpose is to obtain simulation tools allowing the most possible realistic prognosis of the casting structure, including indication, with the highest possible probability, places in the casting that are endangered with the possibility of a gas and shrinkage porosity formation. These problems with elements of model validation are presented in the paper.
Ranque-Hilsch Vortex Tube Potential for Water Desalination
Authors: Stanescu George
Published: March 2013

Virtually any process using high-temperature or high-pressure gas may be a resource for energy recovery. There are many industrial processes resulting in wasted pressurized gases where by using a Ranque-Hilsch Vortex Tube it might be possible to recover some of the wasted pressure energy. Although the magnitudes of the wasted pressure are low in various industrial processes, when the mass flow rates are significant it would be possible to recover large amounts of thermal energy to produce drinking water. This study presents a physical configuration for a Ranque-Hilsch Vortex Tube equipment to produce drinking water and investigate its potential for recovering the wasted pressure energy for seawater desalination. Numerical results show a potential for producing drinking water of 0.005 0.012 kg drinking water/ kg compressed gas when the waste pressures are of order of magnitude 300 700 kPa. Larger potentials are determined when the Ranque-Hilsch Vortex Tube recuperates wasted pressure energy from methane.
Phonon Thermal Conductivity of F.C.C. Cu by Molecular Dynamics Simulation
Authors: Momenzadeh Leila , Evteev Alexander V. , Levchenko Elena V. , Belova Irina V. , Murch Graeme E. , Sohn Yong Ho
Published: March 2013

Phonon dynamics and phonon thermal conductivity of f.c.c. Cu are investigated in detail in the temperature range 200 1300 K within the framework of equilibrium molecular dynamics simulations making use of the Green-Kubo formalism and one of the most reliable embedded-atom method potentials. It is found that the temporal decay of the heat current autocorrelation function of the f.c.c. Cu model at low and intermediate temperatures demonstrates a more complex behaviour than the two-stage decay observed previously for the f.c.c. Ar model. After the first stage of decay, it demonstrates a peak in the temperature range 200 800 K. The intensity of the peak decreases as the temperature increases. At 900 K, it transforms to a shoulder which diminishes almost entirely at 1200 K. It is suggested that the peak may be activated by the influence of the Cauchy pressure in f.c.c. Cu on the phonon dynamics. A decomposition model of the heat current autocorrelation function of a monatomic f.c.c. lattice is introduced. This model can capture all contributions to the function discussed in the literature. It is found that the temperature dependence of the phonon thermal conductivity of the f.c.c. Cu model is in good agreement with previous calculations on the f.c.c. Ar model which follows an exponent close to-1.4, i.e. varies more rapidly than the T-1 law predicted by the theory. The calculated phonon thermal conductivity of the f.c.c. Cu is found to be about one order of magnitude higher than the f.c.c. Ar. This is explained by the inclusion of the electronic contribution to the bulk lattice properties during the fitting of the embedded-atom method potential functions to the experimental orab initiodata. It is demonstrated that the electronic contribution to the total thermal conductivity of f.c.c. Cu dominates over the whole studied temperature range. Nevertheless, the phonon contribution increases as the temperature decreases. The contribution can be estimated to be about 0.5 % at 1300 K and about 5 % at 200 K.
Error Estimates for the Finite Difference Solution of the Heat Conduction Equation: Consideration of Boundary Conditions and Heat Sources
Authors: Davoudi Mohammad Mahdi , Öchsner Andreas
Published: March 2013

This contribution investigates the numerical solution of the steady-state heat conduction equation. The finite difference method is applied to simple formulations of heat sources where still analytical solutions can be derived. Thus, the results of the numerical approach can be related to the exact solutions and conclusions on the accuracy obtained. In addition, the numerical implementation of different forms of boundary conditions, i.e. temperature and flux condition, is compared to the exact solution. It is found that the numerical implementation of coordinate dependent sources gives the exact result while temperature dependent sources are only approximately represented. Furthermore, the implementation of the mentioned boundary conditions gives the same results as the analytical reference solution.
Poisson, Helmholtz and Convection 2D Unsteady Equations by Finite Difference Method of O(Δx6)
Authors: Romão E.C. , de Campos M.D. , Mendes de Moura L.F.
Published: March 2013

This paper presents the numerical solution of transient two-dimensional convection-diffusion-reactions using the Sixth-Order Finite Difference Method. Considering the extension of the Taylor series, the first and second order derivatives from this physical problem are discretized with O(Δx6) accuracy. Using the L and L2 norm, the numerical solution is compared with some examples that have an analytical solution.
Estimation of External Forces in the Rotating System with an Active Magnetic Suspension
Authors: Gizelska Małgorzata , Kozanecka Dorota , Kozanecki Zbigniew , Łagodziński Jakub
Published: March 2013

A method for estimating external forces acting on a rotating machine system with an additional active magnetic support is described. The verification of the method was carried out on the test stand. The force exerted with an impedance hammer and the effect of its action was compared to the estimated results of the magnetic reaction forces determined with the module of the diagnostic software. Obtained results of the investigations have confirmed the usefulness of the proposed method, which leads to finding the right diagnostic balance between the symptom and the cause and securing a rotating system from damage.
Calibration of Cameras and Fringe Pattern Projectors in the Vision System for Positioning of Workpieces on the CNC Machines
Authors: Domek Stefan , Dworak Paweł , Grudziński Marek , Okarma Krzysztof
Published: March 2013

Application of machine vision in automation, robotics and mechatronic systems is one of the most rapidly developing areas of industrial and applied computer science. The vision system presented in the paper can be used for automatic positioning of the workpieces on the numerically controlled machines. The idea of the system is based on the 3D scanning using the fringe patterns approach [ but its accuracy strongly depends on the lighting conditions and the proper calibration of the whole vision system. The most crucial elements for the calibration are both cameras and structural light projectors, as well as the overall geometrical configuration (external parameters in the common coordinate system) and the compensation of the brightness nonlinearities introduced by the structural light sources. In the paper some methods used for the calibration of the experimental system and obtained results are presented.
Low Power, Low Chip Area, Digital Distance Calculation Circuit for Self-Organizing Neural Networks Realized in the CMOS Technology
Authors: Długosz Rafał , Kolasa Marta , Talaśka Tomasz , Pauk Jolanta , Wojtyna Ryszard , Szulc Michał , Gugała Karol , Farine Pierre André
Published: March 2013

This paper presents a new distance calculation circuit (DCC) that in artificial neural networks is used to calculate distances between vectors of signals. The proposed circuit is a digital, fully parallel and asynchronous solution. The complexity of the circuit strongly depends on the type of the distance measure. Considering two popular measures i.e. the Euclidean (L2) and the Manhattan (L1) one, it is shown that in the L2 case the number of transistors is even ten times larger than in the L1 case. Investigations carried out on the system level show that the L1 measure is a good estimate of the L2 one. For the L1 measure, for an example case of 4 inputs, for 10 bits of resolution of the signals, the number of transistors is equal to c. 2500. As transistors of minimum sizes can be used, the chip area of a single DCC, if realized in the CMOS 180 nm technology, is less than 0.015 mm2.
Visualization of the Workpieces on the CNC Machines Using the Virtual Camera Based on the Sub-Pixel IBR Method
Authors: Grudziński Marek , Okarma Krzysztof , Pajor Mirosław , Tecław Mateusz
Published: March 2013

One of the results of the dynamic progress in the field of industrial and applied computer science and mechatronics is the growing interest in usage of the machine vision algorithms and systems. One of such areas of applications is the positioning of the workpieces on the CNC machines based on the image analysis, allowing also the visualization of the workpiece observed from an arbitrary viewpoint located between two or more cameras. Such virtual camera can be effectively implemented using Image Based Rendering technology [ but one of its limitations is the necessity of using the depth maps, which have to be acquired for each reference image. It can be done using the additional fringe patterns projector, similarly as in typical 3D scanning systems or using some other approaches e.g. stereovision. Nevertheless, the quality of images obtained using the typical IBR method is limited by the missing pixels (holes), which should be filled using splatting algorithm, which typically cause the noticeable blurring of obtained image. The solution proposed and discussed in this paper is based on the sub-pixel IBR method with additional filtering and interpolation of the points acquired from the reference cameras allowing increasing the quality of the final images obtained as the visualization of the positioned workpieces.
An Investigation of the Automatic Relative Gravimeters
Authors: Parseliunas Eimuntas , Petroškevičius Petras , Obuchovski Romuald , Birvydiene Rosita
Published: March 2013

The laboratory and field investigations of the several automatic gravimeters Scintrex CG_5 with a quartz elastic system used for the determining of gravity acceleration were performed. Research on characteristics of four gravimeters includes a five-year period. The data consists of gravimetric observations at a laboratory, on the gravimetric testline and at the points of the Lithuanian gravimetric network. The evaluation of the phenomena of the spring systems of the gravimeters was made. The stress on the estimation of the zero drift at a laboratory and field investigations was done. It was detected that zero drift does not exceed 500 μGal per day with a diapason of 200 μGal. The zero drifts per hour do not exceed 25 μGal, mostly they are under 10 μGal. According to the annual calibration results the character of the changes of the linear scale coefficients of the gravimeters were analysed too. The calibration base of 270 km length in Lithuania where the difference of the gravity acceleration of the end points is 201 mGal was used for investigations. The research showed that the biggest deviation from the unit of the linear scale coefficients does not exceed 0.013. It was noted, that the values of the linear scale coefficients of the gravimeters have a tendency to decrease. Also was noted, that the values of the linear scale coefficients have a tendency to decrease in the period between field works, and to increase - in the field works period. So the calibration of the gravimeters should be carried out before and after the field works. Based on measurements carried out during development of the Lithuanian gravimetric network, which consists of 686 gravimetric points, accuracy of gravity acceleration increments was assessed. The comparison of the observations results against the results, obtained by the LaCoste and Romberg gravimeters with metal elastic system, is presented too. The total number of common points is 51. It was stated, that the differences of the gravity accelerations measured by the different types of gravimeters at gravimetric points do not differ more than 10 μGal, therefore maximum difference of 25 μGal was received. The standard deviations of the gravity accelerations of the gravimetric points do not exceed 7 μGal. Such results show the good performance of the SCINTREX CG_5 gravimeters.
Fundamental Laws of Rolling-Element Bearing Mechanics and Diagnostic Methods FAM-C and FDM-A
Authors: Gębura Andrzej , Tokarski Tomasz
Published: March 2013

Rolling-element bearings have been used in the engineering practice since the very beginning of the XIX century. The scientific literature on the subject is therefore rich. As rotational speeds of bearing shafts were getting higher, new problems appeared. Quite a new challenge to be faced were turbine engines with very high rotational speeds that considerably augmented both the scope of problems and the demand for fast and reliable diagnostic methods. The FDM-A diagnostic method (FM frequency modulation, D direct current, C - the level of the methods advancement) has been based on measurements of frequency modulation of the component of pulsation whereas the FAM-C method (FM frequency modulation, C alternating current, C - the level of the methods advancement, i.e. applications in the form of an automatic tester are in use) has been based on measurements of the alternating-current frequency. Both the methods have been developed at ITWL (Air Force Institute of Technology), Warsaw, Poland. Accuracy of these methods essentially results from the natural synchronization of the sampling signal with the angular velocity of kinematic links under examination. The methods enable abrasive wear of a given subassembly to be determined and localised in the course of the power plants regular operation. Possible is determination of numerous parameters of the bearings themselves, the bearing nodes, and the rotating (compressor-turbine) assembly, just to mention the degree of the rolling friction for any of the bearings, the smoothness of motion of the bearing cage, sizes of radial clearances, the level of abrasive wear of contact surfaces of both the bearing cage and the rolling element. A diagnostic unit is fitted to any item, e.g. an electrical joint, supplied with DC or AC voltage. What has been presented in the paper is findings from the performance testing of the aircraft turbine engine: the role of the generator observer has been played by a DC generator and a three-phase tachogenerator.
Detection of Cesium from Pollucite Using Laser-Induced Breakdown Spectroscopy
Authors: Ikezawa Satoshi , Wakamatsu Muneaki , Ueda Toshitsugu
Published: March 2013

The purpose of this research is to detect the atomic spectrum of cesium using laser-induced breakdown spectroscopy (LIBS). In this study, pollucite ((Cs,Na)(AlSi2)O6.nH2O) was used as a test sample for the LIBS measurement. LIBS is a useful tool for the determination of the elemental composition of various materials and it does not require any preprocessing step. The Nd:YAG laser was operated at 1064 nm to generate a 50-mJ Q-switched pulse with a width of 8 ns (full width at half maximum, FWHM). The breakdown emissions were dispersed by a grating with a groove density of 1200 lines/mm and the resulting electrical signal was recorded using a streak camera. The plasma intensity was optimized with respect to the background. Spectral measurements were carried out after an appropriate delay time to allow for the decay of the continuum radiation. In the experiments, 100 laser shots were used to record data for each spectrum in ambient air. The results of the experiments showed that the atomic signals corresponding to pollucite were obtained easily by LIBS measurements. Thus, spectrum peaks due to cesium, sodium, aluminum, and silicon are observed. In particular, the characteristics of the cesium spectrum play an important role in establishing the LIBS system for environmental monitoring, which may be used to detect radioactive elements emitted from nuclear plants.
Determination of the Shot Energy Characteristics of the Pneumatic Gun by Means of High Speed Imaging Method
Authors: Jóźwik Wojciech , Zbrowski Andrzej
Published: March 2013

The article presents the method for the determination of energy characteristics of the pneumatic cannon by means of high speed imaging. The gun tested is a device enabling bird collision endurance tests to be conducted for the structural element of aircrafts. In the tested 250 [m system, the projectiles were thrown in the plastic sabot damaged in the muzzle of the gun. The tests were conducted in the speed ranging between 100 300 m/s for 0.9 and 3.6 [k projectiles. The objective of the tests was to determine the characteristics of the projectile outlet velocity in the feed pressure function. The measurement stand was equipped with the Phantom V310 high speed camera The speed measurement was conducted with the use of the digital image analysis in which commercial TEMA Motion software was used. Results were corrected so that the parallax error could be eliminated. Because of the cylindrical shape of the projectile, the parallax error for the front at the back of the projectile varied, which required two correction coefficients to be applied. The speed was calculated by the averaging of the results for the front and the back of the projectile. For the recordings, in which the remaining of the sabot prevented the accurate arrangement of measurement points, a simplified speed measurement method was used. Measurement uncertainty sources are also described (shift of the projectile at the time of the exposure, measurement point positioning error). The influence of the parallax error on the measurement result and the cannon energy characteristics obtained are presented. The obtained characteristics enable proper selection of feed pressure allowing for the procurement of the outlet velocity suitable for the tests conducted.
Effect of Cross Section Size on Ductility and Fragmentation of Copper Ring at High Strain Rate Loading Conditions
Authors: Janiszewski Jacek
Published: March 2013

In the present work, different copper ring samples geometries with a small aspect ratio of 0.5 or 1 were subjected to an experimental study under electromagnetic expanding ring test conditions. The experimental multiple ring tests were performed under similar loading conditions, that is, the applied maximum expansion velocities covered a range from 128 to 147 m/s (7.4 103s-1) for all ring samples geometries, with the exception of rings with a cross section of 1 mm x 0.5 mm. For these rings, the averaged maximum expansion velocity was higher and equal to 195 m/s (1.2 104s-1). The results of experimental investigations revealed a minor influence of the applied cross section sizes on ductility of copper rings, whereas its fragmentation seems to be dependent on a ring cross section area.
Experimental Shear Stress Analysis of the Thin Walled Aluminum Hollow Shaft under Torsion
Authors: Gürbüz Riza , Donertas Mehmet Ali , Yavuz Mehtap
Published: March 2013

In this experimental study, maximum torsion shear stresses occurring on the hallow aluminum shaft under various small torsion loads were measured with strain gauge, data acquisition cards and computer. Special software was developed to measure maximum strain and stress on the thin aluminum hollow shaft. Stress values occurring on the aluminum hallow shaft under various small loads were measured with strain gauge and those strain values were transmitted to computer directly with data acquisition cards. Using the strain, the load and other constant values of the material (Torsion stress, outside and inside diameters of shaft, length of shaft, shear stress modulus, applied torque loads, twist angle of shaft etc) the stress values occurring on the hallow shaft are calculated by computer program and the stress-strain graph is drawn on the computer screen automatically [Refer to table1 Fig. 2,3,4 ,5 and . In this experimental study, the theoretical knowledge given in the books and experiment results obtained under laboratory conditions were compared with each other. The obtained results were almost same. Similar experimental application could be used for real applications in car industry and mobile machines [.
Laboratory Station for Research on Angular Translocation in Human Lower Limbs
Authors: Ostaszewski Michał , Siemieniako Franciszek
Published: March 2013

In the article a construction of a laboratory station for determination of angles in three kinematic pairs of human lower limbs exoskeleton is described. The constructed exoskeleton is supposed to support human lower limbs only on plane vertical to ground. In article the results of measurement of movement parameters of walking human lower limbs obtained using the measuring station. Measurement of angular displacement on the station is realized using six angular displacement absolute transducers. The station is also one of the components contained in lower limb exoskeleton being constructed. The measuring construction will be used to identify actuating systems during exoskeleton construction phase.
Mechatronic Elements for Measuring Systems
Authors: Giniotis Vytautas , Rybokas Mindaugas , Dmitrijev Gintaras , Sabaitis Deividas , Šiaudinytė Lauryna , Janulevičius Justinas
Published: March 2013

This presentation deals with a new application of mechatronic means for angle measuring system; it can be applied in precision instrumentation and measurement equipment. Precise angle measuring is based on usage of angle measurement standards such as polygons, precision indexing tables and circular scales. Ring lasers and precision rotary encoders can also be used for this purpose as well as test benches created for angle calibration. Many angular and linear measurement transducers or encoders are used in industry and machine engineering for the position and displacement measurement. The accuracy of angular position fixed by means of these devices reach approximately 0.3" 0.1" (arc second). Control of their accuracy parameters is complicated task consisting from some high requirements needed for rotation, positioning, signal processing, object adjustment and data processing.