bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing Properties and Performance of Cellulose Acetate/Polyethylene Glycol (CA/PEG) Membrane with the addition of Titanium Dioxide (TiO2) by Using Surface Coating Method
Authors: Nurkhamidah Siti , Rahmawati Yeni , Gunardi Ignatius , Alifiyanti Pitsyah , Dimas Priambodo Krisna , Luthfi Zaim Ryanda , Eka Muqni Wahyuni
Published: March 2018

In this study, cellulose acetate/polyethylene glycol (CA/PEG) membrane with composition 80/20 was prepared by phase inversion method. Titanium dioxide with different number has been added by using surface coating. Hydrophilicity, morphology, flux permeate and salt rejection of membranes has been studied. The hydrophilicity is determined by Fourier-Transformed Infra-Red (FTIR) spectra and contact angle analysis. Surface and fractured morphology are identified by using Scanning Electron Microscopy (SEM). The experiment results show that hydrophilicity of CA/PEG membrane increases with the addition and the increasing of TiO2 contents. However, with further increasing of TiO2, hydrophilicity of CPT membrane decreases. The optimum membrane is CA/PEG/TiO2 80/20/1,25 g/L solvent (CPT 3) with flux permeate of 111,82 L.m-2h-1 and salt rejection of 48,30%.
Design of pallet, frame and chain of soldering station conveyor
Authors: Blatnická Mária , Sága Milan , Blatnický Miroslav
Published: March 2018

The paper deals with constructional procedure and design of the soldering station for compressor outlet piping. The design of the mechanism is based on the need to create a device that will be able to move the pallet with the compressor between individual operational positions of the entire conveyor line.
A computer simulation of solidification taking into account the movement of the liquid phase
Authors: Dyja Robert , Gawrońska Elżbieta , Grosser Andrzej
Published: March 2018

In the paper, we present the results of solidification simulation taking into account the movement of the liquid phase. The results are obtained from an author software which is implemented on the base of a stabilized finite elements method (Petrov-Galerkin formulation). Using that formulation the Navier-Stokes equation is solved together with the convection term (Boussinesq approximation). The Finite Element Method (FEM) formulation is responsible for solidification, approximating the solution of the heat conduction equation (with the internal heat source term responsible for the heat released during the phase transition). The movement of the liquid phase in a solidifying cast that is caused by convection can significantly affect the process of heat transfer from the casting to the mold, which in turn has an influence on the temperature distribution in the cast and may cause a change in the location of the defects. The presented results allow to assess under what conditions the effect of convection on the solidification process is significant.
The role of inflow boundary layer thickness for numerical modelling of flow around bluff bodies of built-up areas
Authors: Gnatowska Renata
Published: March 2018

The paper presents the numerical results obtained with the use of the ANSYS FLUENT commercial code for analysing the flow structure around a two rectangles in line surface-mounted bluff bodies immersed in a boundary layer. The simulation of a configuration with a flow around objects has been done using both the steady and unsteady approaches. Effects of the inflow boundary layer thickness on the flow field, wall-shear stress and the grid resolution accuracy in predicting periodic vortex shedding from two tandem arrangement bodies are examined. It has been observed that the periodic vortex shedding is considerably reduced with an increase in the δ/H parameter.
Experimental and computational comparative study of the specimens loaded by bending and torsion
Authors: Jakubovičová Lenka , Vaško Milan , Sága Milan , Kopas Peter
Published: March 2018

The article presents the theoretical and computational analysis of the fatigue tested specimens loaded by bending and torsion. The testing device allows loading by constant turn of the clamping parts. The stress and strain magnitude in test depends on the material characteristics and shape of the specimen. The calculations are realized by finite element method (FEM). The obtained results are verified with the experimental measurement applying the optical system ARAMIS.
Numerical modelling of caustics of solid state disk lasers
Authors: Kubiak Marcin
Published: March 2018

This paper concerns mathematical modelling of caustics of solid state laser YAG type with the disk active medium. The heat source model is developed on the basis of interpolation algorithms using geostatistical kriging method. The real laser beam power distribution and caustics are taken into account in the model. Measurements of laser beam power distribution and diameter of the laser beam spot for different focusing are performed using UFF100 analyzer. Yb:YAG laser emitted by Trumpf laser head D70 is used in the experiment. Presented results include the comparison of experimentally determined laser power intensity distribution and caustic with results obtained by developed interpolation model.
The use of CAD applications in the design of shredders for polymers
Authors: Macko Marek , Tyszczuk Krzysztof , Śmigielski Grzegorz , Flizikowski Józef , Mroziński Adam
Published: March 2018

Computer-aided design is now the primary design tool, providing opportunities for improving project quality, allowing for in-depth analysis of the specific features of the solution. In the methodology, computer simulation applications were used. Computer simulation aims to reconstruct the course of the studied process from its mathematical model using a computer and to examine the influence of the environment (input signals) and the internal properties of the object (process parameters) on the characteristics of the object. In designing the shredder, in addition to the selection of structural features, it is also possible to perform strength and kinematic simulations, resulting in a higher quality of the target solution. The results of the simulation work presented in the paper indicate a wide range of possible applications - also in the field of food engineering and processing of polymers - eg shredder mechanisms. Particular attention has been paid to the reduction of energy consumed by the deformation of samples, eg by pre-compaction of sample before introduction to the working area of the shredder. It has been estimated that the gap between the rotating discs should be minimized. Establishing design guidelines has resulted in a number of concept designs.
Transformation of heat into mechanical energy by means of rotating systems
Authors: Mešina Marian
Published: March 2018

All heat engines need two different temperatures for their work, T1<T2. The efficiency is limited by the Carnot formula from above. This article presents a new conception for heat engines. Unlike conventional heat engines, the working medium has an additional degree of freedom, the rotation around a given axis. The heat introduced and removed can not only lead to a change in the parameters of temperature, pressure, and volume, which are considered in conventional thermodynamics, but also to a change in the state of rotation. The rotational speed must also be taken into account in all phases of the cycle for all efficiency calculations. In many cases, this leads to a surprisingly different result from the results of conventional thermodynamics, that the efficiency of the cycle can exceed the Carnot limit. The efficiency values depend not only on temperatures and rotational speeds, but also on the material data. The proposed new type of heat engine makes it possible to better utilise very small temperature differences and under certain conditions, in combination with an ideal heat pump, to extract ambient heat and convert it into mechanical energy. The calculated results were presented for simple geometry and can easily be verified experimentally. In combination with an ideal heat pump, the proposed heat engine facilitates the surroundings to withdraw heat and convert it into mechanical work.
Simulation of solidification during crystallization under pressure
Authors: Pastirčák Richard , Brůna Marek , Bolibruchová Dana
Published: March 2018

The paper deals with squeeze casting technology. The influence of process parameters variation (casting temperature, mold temperature, pressure) will be observed. The experimentally obtained boundary conditions (heat flow, HTC) will be verified using the ProCast simulation software. Shape influence on the mold filling process and the temperature field under pressure will be evaluated. To evaluate the mechanical properties, a tensile test was performed. Three identical samples were cast for each parameters change. From these samples the average values of the mechanical properties were measured and calculated. The thickness of the flat test samples was 3.15, 4, 5, 6.3, 8 mm with a sample width of 10 mm. For gravity cast of the casting, the mechanical properties of the thinner parts were higher. At the pressure influenced castings, the mechanical properties were higher in the thicker parts of the casting.
The effect of the gantry crane beam cross section on the level of generated stresses
Authors: Sowa Leszek , Skrzypczak Tomasz , Kwiatoń Paweł
Published: March 2018

The gantry cranes are currently one of the most popular devices to transporting loads. They can be used in many industries. This study focuses on the numerical analysis of only the portable gantry crane. The mathematical and numerical model of mechanical phenomena in the gantry crane beam was presented in this paper. This problem was solved by using of the Finite Element Method (FEM). The analysis was made to the cross-section of gantry crane beam which was the I-beam or box beam. The numerical simulations are limited to numerical analysis of strength of the gantry crane beam which was loaded by the motion of the load force along its length. As a result of the calculations, the stresses and displacements of the structure of gantry crane were obtained. The influence of beam shape change and changing the loading force position on generate the equivalent stress in the crane beam was evaluated. The research performed, which allows the estimated of the stress state, pointing out the critical areas and values, were made in order to increase the strength of the structure of the gantry crane.
Analysis of transverse vibration and stability issues of discrete-continuous elastic systems with nonlinearly variable parameters
Authors: Jaroszewicz Jerzy , Dragun Łukasz
Published: March 2018

The work is devoted to methods of analysis of vibrations and stability of discrete-continuous, multi-parameter models of beams, shafts, rotors, vanes, converting to homogeneous and one-dimensional. The properties of Cauchy's influence function and the characteristic series method were used to solve the boundary problem. It has been shown that the methods are an effective tool for solving boundary problems described by ordinary fourth-and second-order differential equations with variable parameters. Particular attention should be paid to the solution of the border problem of two-parameter elastic systems with variable distribution of parameters. Universal beam-specific equations with typical support conditions including vertical support, which do not depend on beam shape and axial load type, are recorded. The shape and type of load are considered in the form of an impact function that corresponds to any change in cross-section of the support and continuous axial load, so that the functions describing the stiffness, the mass and the continuous load are complete. As a result of the solution of the boundary vibration problem of freely bent support and any change in its cross-section, loaded with any longitudinal load, arranged on the resilient substrate, strict relations between the own frequency parameters and the load parameters were derived. Using the methods, simple calculations were made, easy to use in engineering practice and conditions of use were given. Experimental studies have confirmed the high accuracy of theoretical calculations using the proposed methods and formulas.
The assessment of the integration methods for the rail vehicle ride dynamics solution
Authors: Lack Tomáš , Gerlici Juraj
Published: March 2018

The article is devoted to the analysis of the dynamic characteristics of the mechanical system composed of rigid bodies mutually connected with flexible bindings that represent springs and dampers. The analysed system represents the rail vehicle, which is distinguished by the contact link between the wheel and rail, or wheelsets and the track. Currently, analyses of similar type are carried out basically by using commercially distributed software packages, where you enter inputs (which the input forms allow) and the user may achieve results respecting the handling procedures. In accordance with the different approaches to solutions of partial solutions of the issue, the results of the simulations can differ. In the article the theoretical analysis is conducted the parameters of calculation are set out and the results are compared with the results obtained from the calculation by SIMPACK.
Y25 freight car bogie models properties analysis by means of computer simulations
Authors: Lack Tomáš , Gerlici Juraj
Published: March 2018

The article deals with the results of the simulation analysis of a railway wagon bogie model. We analysed four freight wagon bogie variants for its dynamics properties research. The bogie models correspond in general to the Y25 bogie concept. The models were created in SIMPACK software enhanced by the RAIL module. From the research results depicted in the graphs we found out, that the newly designed bogie variant gives the best results when compared to the other analysed versions. The newly designed model consists of a standard Y25 bogie frame with two Lenoire friction dampers. This bogie is equipped with longitudinal linkages on both sides. These linkages are completed with a radial torsion binding, torsion rod, between side bogie parts. The contact of railway wheels and rails generates active forces affecting the surface contact, affecting the size of the normal and tangential stress, wear surfaces of the wheel/rail, or directly the size of the derailment.
Probability analysis of dynamical effects of axial piston hydraulic motor
Authors: Sapietova Alzbeta , Dekys Vladimír , Sapieta Milan , Sulka Peter , Gajdos Lukas , Rojek Izabela
Published: March 2018

The paper presents an analysis of impact force on stopper screw in axial piston hydraulic motor. The solution contains probabilistic description of input variables. If the output parameters of probabilistic solution are compared with arbitrary values and values acquired by analytical solution, the probability of proper operation of the device can be evaluated.
Analysis and synthesis parameters influencing to the effects of impact
Authors: Šulka Peter , Sapietová Alžbeta , Dekýš Vladimír , Sapieta Milan
Published: March 2018

In the solutions will be presented to the interaction of two bodies loaded with impact effects in the environment of software MSC. ADAMS. By performing a sensitivity analysis of the parameters influencing to the effects of impact and function parameters of impact will be obtained parameters for optimum setting MSC.ADAMS for acquirement feedback, as the most identical with reality.
Influence of geometrical parameters of convergent sleeve on the value of limit stress
Authors: Górecki Jan , Malujda Ireneusz , Talaśka Krzysztof , Wilczyński Dominik , Wojtkowiak Dominik
Published: March 2018

This paper presents the results of research on improving the effectiveness of the agglomeration process. Improving effectiveness was obtained as a result of the application of the convergent sleeve. The sleeve is mounted before the multi-holes die in the dry ice agglomeration machine. The empirical part of the paper presents the results of research on which FEM model was based. The numerical part of research presents the FEM model of the agglomeration process. The FEM model with a known uncertainty level was used to determine the influence of geometrical parameters of the sleeve on the limit value of the agglomeration forces. The model will be one of the starting points for the design and construction of the machine for the compaction and granulation of dry ice.
Influence of microscopic casting defects on fatigue endurance of ductile cast iron
Authors: Nový František , Kopas Peter , Bokůvka Otakar , Jambor Michal , Trško Libor
Published: March 2018

In this work, there are published results about fatigue endurance of ductile cast iron obtained at high-frequency sinusoidal cyclic push-pull loading in the ultra-high cycle fatigue region. The main attention was focused on the fatigue lifetime data scatter caused by the influence of microscopic casting defects (microshrinkages, microbubbles, microcracks, non-metallic inclusions and local clusters of big graphitic nodules).
Numerical modelling of sandwich panels with a non-continuous soft core
Authors: Pozorska Jolanta
Published: March 2018

The paper presents the problem of static analysis of sandwich structures with a non-continuous soft core. In the numerical 3D FE models, the core is divided into separated parts. The contact between these parts has the form of unilateral constraints. The model also allows for local debonding of the facing and local imperfections of sandwich panel geometry. Particular attention is paid to the problem of local instability of the facing that is compressed during bending. The phenomenon of progressive damage and the influence of non-continuity of the core on the structural behavior of the sandwich panel is also discussed.
Modification of alternative additives and their effect on the rubber properties
Authors: Ondrušová Darina , Božeková Slavomíra , Buňová Lenka , Pajtášová Mariana , Labaj Ivan , Dubec Andrej , Vršková Juliána
Published: March 2018

The present paper deals with a targeted modification of two kinds of alternative additives - waste from glass production and natural mineral filler and explores their effect on the properties of polymeric materials. In the function of first alternative filler was used sludge from weighing the ingredients of glass batch in the glass production. The second used was natural aluminosilicate material based on zeolite (clinoptilolite). These alternative fillers have been modified in order to increase its efficiency, using the silanes: 3-aminopropyl-triethoxysilane, bis(triethoxysilyl)propyl-tetrasulfide and 3-(triethoxysilyl)propyl-methacrylate. In the case of alternative filler based on zeolite the influence of silanization conditions on the filler efficiency have been also studied. Prepared modified fillers were mixed into rubber compounds as partial replacement of commonly used filler – carbon black. The influence of prepared fillers on rheology and curing characteristics of rubber compounds and also on physical and mechanical properties of vulcanizates has been studied. Obtained results of measured characteristics of polymeric systems containing prepared alternative fillers were compared with the results obtained in the case of reference rubber compound with a commertially used filler – carbon black.
Structural changes of selected materials for glass industry after thermal loading
Authors: Pešlová Františka , Janeková Mariana , Krum Stanislav
Published: March 2018

The presented paper is focused on study and investigation of structural changes in relation to the selected materials which are exposed to the thermal loading. The given work is connected with closer investigation of such material as Dominial ZF 2 which is commonly used for production of steel moulds and components in the glass industry. Moreover, the given work is also devoted to the investigation of materials which are commercially called Toolox 33 and Toolox 44 because these materials were proposed by firm to be used as substitutive materials of Dominial ZF 2. Both of the mentioned and investigated materials have not been used in glass industry yet. Experimental procedures were proposed on the basis of the fact that the investigated materials are exposed to thermal as well as mechanical loading and they are in direct interaction with hot molten glass. After simulated thermal loading, the investigated materials were exposed to the static tensile test and by this way, it was possible to obtain samples with fracture surfaces and these fracture surfaces were evaluated in terms of characteristic features relating to rupture. On the basis of the obtained results and knowledge from experimental procedures, Toolox 33 and Toolox 44 are not recommended to be used for production of steel moulds and components for glass products.
Comment le nucléaire
peut-il accompagner
la réinvention engagée
dans la société civile ?
Authors: Le Ngoc Boris
Published: March 2018

Quelle place pour l’énergie nucléaire dans le monde
de demain ? Pour répondre à cette vaste question,
la Société française d’énergie nucléaire, en collaboration
avec la direction des études d’EDF, a travaillé pendant
plusieurs mois avec le cabinet de prospective Sociovision,
expert dans la compréhension et l’anticipation
des changements de la société. Nous vous livrons ici
les éléments de cette étude qui aura permis de comprendre
quelles sont les attentes sociétales des Français et aura
permis d’imaginer ce que pouvait être le rôle de l’énergie
nucléaire dans la transformation engagée dans la société.
Scénario pour demain…
Si Google s’en mêlait…
Authors: Ladet Michel
Published: March 2018

Dans ce scénario, la mutation technologique des sociétés
modernes s’accélère, poussée par la transformation
numérique et par une nouvelle vague de mondialisation
où les géants d’Internet prennent l’initiative dans l’énergie,
avec un optimisme technologique et un désir de croissance
qui marginalise les discours de restrictions du 100 %
renouvelables. Ce contexte, orienté bas carbone, serait
très favorable à un renouveau du nucléaire, mais avec une
filière, un mode de financement, et un esprit de coopération
internationale totalement réinventés. Le scénario esquissé ici
s’appuie sur l’évolution des aspirations des populations dans
le monde, mesurée par l’International Observer de Sociovision,
sur la communication des grands acteurs du numérique
relative à l’énergie, sur le phénomène des start-up du nucléaire
aux États-Unis ainsi que sur les projets Chinois récents.
Tensions et tiraillements :
les Français face au nucléaire
Authors: Witkowski Didier
Published: March 2018

Le nucléaire est un défi permanent pour les études
d’opinion. Comme pour tous les sujets qui sont à la fois
complexes et éloignés des préoccupations quotidiennes,
les réponses aux enquêtes varient considérablement
selon les formulations choisies et l’ordre des questions.
Cette fragilité est maximale lorsqu’on demande aux
interviewés d’exprimer une opinion de principe, de type
référendaire, « pour » ou « contre », qui est évidemment
très tentante pour produire un résultat médiatiquement
avantageux mais qui, en réalité, place une bonne partie
de l’échantillon interrogé dans une situation de malaise.
Dès lors, comment évaluer la position des Français à l'égard
du nucléaire ? Et, au-delà de la méthodologie, quels sont
les critères qui déterminent le soutien et/ou la désaffection
à telle ou telle énergie ? Décryptage.
ABC analysis of the customers using axiomatic design and incomplete rough set
Authors: Gholami Atena , Sheikh Reza , Mizani Neda , Sana Shib Sankar
Published: March 2018

Customer’s recognition, classification, and selecting the target market are the most important success factors of a marketing system. ABC classification of the customers based on axiomatic design exposes the behavior of the customer in a logical way in each class. Quite often, missing data is a common occurrence and can have a significant effect on the decision- making problems. In this context, this proposed article determines the customer’s behavioral rule by incomplete rough set theory. Based on the proposed axiomatic design, the managers of a firm can map the rules on designed structures. This study demonstrates to identify the customers, determine their characteristics, and facilitate the development of a marketing strategy.
Stoffwechselkrankheit Gicht
Authors: Reuss-Borst Monika , Tausche Anne-Kathrin
Published: March 2018

Die Gicht ist die häufigste entzündliche Gelenkerkrankung. Ihr liegt mit der Hyperurikämie als Ursache eine metabolische Störung zugrunde. Abgelagerte Harnsäurekristalle führen zu den typischen anfallsartigen Gelenkentzündungen. In den letzten Jahrzehnten ist die Gichtinzidenz zusammen mit anderen metabolischen Erkrankungen zunehmend. Der Rheumatologe ist besonders gefragt, wenn sich die Gicht klinisch nicht typisch manifestiert (oligo- und polyartikulär), also andere Differenzialdiagnosen infrage kommen, wenn bereits Komplikationen aufgetreten sind (fortgeschrittene Arthropathie, tophöse Gicht, zunehmende Nierenfunktionseinschränkung) oder wenn sich die Therapie aufgrund von Komorbiditäten schwierig gestaltet. Im Allgemeinen ist die Diagnostik der Gicht für den erfahrenen Rheumatologen keine Herausforderung, zumal er über Tools wie die Gelenksonografie und Gelenkpunktion mit mikroskopischer Beurteilung von Synovialflüssigkeit verfügt. Auch erscheint die Behandlung der Gicht als „treat-to-target“-Konzept in Analogie zu anderen entzündlich-rheumatischen Erkrankungen und aufgrund effektiver therapeutischer Optionen vergleichsweise übersichtlich. Immer wieder kommt jedoch die Frage nach eventuell modifizierbaren Faktoren bei der Entstehung der Hyperurikämie und Gicht auf. Die vorliegende Arbeit richtet den Fokus auf die Beeinflussung der zugrundeliegenden metabolischen Ursachen unter Berücksichtigung aktueller wissenschaftlicher Erkenntnisse. Ziel ist es, den Fokus von der rein symptomatischen Therapie der Entzündung im Gichtanfall hin auf die kausale Beeinflussung der metabolischen Harnsäure-Homöostase zu richten. Dazu gehört neben diätetischen Maßnahmen auch die Modifikation von Harnsäure-erhöhenden Faktoren wie Komedikationen.
Senologische Befunde bei CT-Untersuchungen des Thorax: eine retrospektive Auswertung
Authors: Krug Kathrin , Houbois Christian , Grinstein Olga , Borggrefe Jan , Puesken Michael , Hanstein Bettina , Malter Wolfram , Maintz David , Hellmich Martin
Published: March 2018

Ziel Die Rate inzidenteller Mammakarzinomen bei CT-Untersuchungen wird basierend auf Auswertungen der Befundberichte mit ≤ 2 % beziffert. Wegen der ansteigenden Frequenz von CT-Untersuchungen und der hohen Prävalenz von Mammakarzinomen sollten Häufigkeit und Art senologisch falsch negativer CT-Befunde auf der Basis retrospektiver Bildauswertungen überprüft werden.

Material und Methoden Alle erstmalig im Jahre 2012 durchgeführten KM-gestützten CT-Untersuchungen des Thorax bei volljährigen Patientinnen wurden retrospektiv eingeschlossen. Ein Radiologe wertete alle Bilddokumentationen nach BI-RADS hinsichtlich senologischer Herdbefunde aus. Alle BI-RADS ≥ 3 Einstufungen wurden von einem 2. Auswerter überprüft und bei divergierender Einschätzung im Konsens besprochen. Basierend auf allen klinischen, radiologischen und pathologischen Angaben wurden Referenzdiagnosen erarbeitet. Die senologischen Informationen der Befundberichte wurden retrospektiv nach BI-RADS klassifiziert und mit den retrospektiven Konsensauswertungen und den Referenzdiagnosen abgeglichen.

Ergebnisse Das Spektrum der Indikationen umfasste Staging und Verlaufskontrollen von soliden Organtumoren/Lymphomen (N  =  701, 59,9 %) sowie vaskuläre (190, 16,2 %), entzündliche (48, 4,1 %) und pneumologische (22, 1,9 %) Fragestellungen. BI-RADS 1/2 Befunde lagen bei 92,5 % und BI-RADS 6 Befunde bei 1,7 % der 1170 Untersuchungen vor. Bei 68 Untersuchungen (5,8 %) wurden retrospektiv BI-RADS 3 – 5 Befunde beschrieben, die in 57 Fällen als benigne (46; 3,9 %) oder maligne (11; 0,9 %) einzustufen waren. 13 BI-RADS 4/5 Einstufungen (1,1 %) der Konsensauswertungen waren falsch positiv. Die beiden gesicherten falsch negativen CT-Befunde (0,2 %) waren therapeutisch und prognostisch nicht relevant.

Schlussfolgerung Bei der kurativen Diagnostik überwiegend nicht senologischer Fragestellungen betrug die relative Häufigkeit von BI-RADS 3 – 5 Befunden 5,8 %. Die Raten gesicherter falsch positiver retrospektiver BI-RADS 4/5-Befunde (1,1 %) und falsch negativer CT-Befundberichte (0,2 %) weichen naturgemäß von Werten aus einem senologischen Screening ab. Aussagen zur Prävalenz des okkulten Mammakarzinoms sind aufgrund des selektierten Kollektivs, der teils unvollständigen Parenchymerfassung und des retrospektiven Ansatzes nur mit Einschränkungen möglich.
Brustkrebs und Alkohol
Authors: Kerschbaum Eva
Published: March 2018

Der Zusammenhang zwischen Alkohol und Brustkrebs steht im Fokus der Wissenschaft, da der genaue Mechanismus, über den Alkohol eine Brustkrebserkrankung fördern kann, noch nicht geklärt ist. Fachgesellschaften wie die IARC (International Agency for Research on Cancer) sehen Alkohol als gesicherten Risikofaktor für Brustkrebs. Die akzeptable Alkoholmenge liegt laut D-A-CH-Referenzwerten bei nur 10 g/Tag für gesunde Frauen und 20 g/Tag (ca. 0,5 l Bier oder 0,25 l Wein oder Sekt) für gesunde Männer. Da Alkohol in vielen Kulturen verwurzelt ist und hierzulande viele junge Frauen teilweise große Mengen Alkohol konsumieren, ergibt sich daraus ein besorgniserregendes Gesundheitsproblem. Diesem kann durch einen gesunden Lebensstil mit ausgewogener Ernährung, ausreichend Bewegung, der Vermeidung von Übergewicht und einem eingeschränkten Konsum von Alkohol begegnet und ein Großteil der Krankheitsfälle verhindert werden.
Nonlinear multiphysics and multiscale modeling of dynamic ferromagnetic–thermal problems
Authors: Yan Su , Kotulski Joseph D. , Jin Jian-Ming
Published: March 2018

A coupled ferromagnetic–thermal solver is developed for the multiphysics and multiscale modeling and simulation of nonlinear magnetic materials in the time domain. By adopting a temperature-dependent dynamic hysteresis model, the power loss is characterized and calculated from the solution of Maxwell's equations, which serves as the heat source for the thermal problem. By solving the thermal problem, the temperature change is obtained, and its effect on the magnetic material property can be quantified, which is then coupled back to Maxwell's equations. Due to different temporal characteristics of the electromagnetic fields and the thermal response, the resulting coupled ferromagnetic–thermal system has two significantly different time scales. Such a temporal multiscale issue is addressed with a proposed multiscale time integration method to account for the multiscale coupling between the two physics. With the proposed multiphysics and multiscale modeling method, both the electromagnetic fields and the thermal responses can be captured accurately in a dynamic operation.
Defects controlling electrical and optical properties of electrodeposited Bi doped Cu2O
Authors: Brandt Iuri S. , Tumelero Milton A. , Martins Cesar A. , Plá Cid Cristiani C. , Faccio Ricardo , Pasa André A.
Published: March 2018

Doping leading to low electrical resistivity in electrodeposited thin films of Cu2O is a straightforward requirement for the construction of efficient electronic and energy devices. Here, Bi (7 at. %) doped Cu2O layers were deposited electrochemically onto Si(100) single-crystal substrates from aqueous solutions containing bismuth nitrate and cupric sulfate. X-ray photoelectron spectroscopy shows that Bi ions in a Cu2O lattice have an oxidation valence of 3+ and glancing angle X-ray diffraction measurements indicated no presence of secondary phases. The reduction in the electrical resistivity from undoped to Bi-doped Cu2O is of 4 and 2 orders of magnitude for electrical measurements at 230 and 300 K, respectively. From variations in the lattice parameter and the refractive index, the electrical resistivity decrease is addressed to an increase in the density of Cu vacancies. Density functional theory (DFT) calculations supported the experimental findings. The DFT results showed that in a 6% Bi doped Cu2O cell, the formation of Cu vacancies is more favorable than in an undoped Cu2O one. Moreover, from DFT data was observed that there is an increase (decrease) of the Cu2O band gap (activation energy) for 6% Bi doping, which is consistent with the experimental results.
Complexation reactions in pyridine and 2,6-dimethylpyridine-water system: The quantum-chemical description and the path to liquid phase separation
Authors: Chernia Zelig , Tsori Yoav
Published: March 2018

Phase separation in substituted pyridines in water is usually described as an interplay between temperature-driven breakage of hydrogen bonds and the associating interaction of the van der Waals force. In previous quantum-chemical studies, the strength of hydrogen bonding between one water and one pyridine molecules (the 1:1 complex) was assigned a pivotal role. It was accepted that the disassembly of the 1:1 complex at a critical temperature leads to phase separation and formation of the miscibility gap. Yet, for over two decades, notable empirical data and theoretical arguments were presented against that view, thus revealing the need in a revised quantum-mechanical description. In the present study, pyridine-water and 2,6-dimethylpyridine-water systems at different complexation stages are calculated using high level Kohn-Sham theory. The hydrophobic-hydrophilic properties are accounted for by the polarizable continuum solvation model. Inclusion of solvation in free energy of formation calculations reveals that 1:1 complexes are abundant in the organically rich solvents but higher level oligomers (i.e., 2:1 dimers with two pyridines and one water molecule) are the only feasible stable products in the more polar media. At the critical temperature, the dissolution of the external hydrogen bonds between the 2:1 dimer and the surrounding water molecules induces the demixing process. The 1:1 complex acts as a precursor in the formation of the dimers but is not directly involved in the demixing mechanism. The existence of the miscibility gap in one pyridine-water system and the lack of it in another is explained by the ability of the former to maintain stable dimerization. Free energy of formation of several reaction paths producing the 2:1 dimers is calculated and critically analyzed.
Determining the phonon energy of highly oriented pyrolytic graphite by scanning tunneling microscope light emission spectroscopy
Authors: Uehara Yoichi , Michimata Junichi , Watanabe Shota , Katano Satoshi , Inaoka Takeshi
Published: March 2018

We have investigated the scanning tunneling microscope (STM) light emission spectra of isolated single Ag nanoparticles lying on highly oriented pyrolytic graphite (HOPG). The STM light emission spectra exhibited two types of spectral structures (step-like and periodic). Comparisons of the observed structures and theoretical predictions indicate that the phonon energy of the ZO mode of HOPG [M. Mohr et al., Phys. Rev. B 76, 035439 (2007)] can be determined from the energy difference between the cutoff of STM light emission and the step in the former structure, and from the period of the latter structure. Since the role of the Ag nanoparticles does not depend on the substrate materials, this method will enable the phonon energies of various materials to be measured by STM light emission spectroscopy. The spatial resolution is comparable to the lateral size of the individual Ag nanoparticles (that is, a few nm).
Implicit ligand theory for relative binding free energies
Authors: Nguyen Trung Hai , Minh David D. L.
Published: March 2018

Implicit ligand theory enables noncovalent binding free energies to be calculated based on an exponential average of the binding potential of mean force (BPMF)—the binding free energy between a flexible ligand and rigid receptor—over a precomputed ensemble of receptor configurations. In the original formalism, receptor configurations were drawn from or reweighted to the apo ensemble. Here we show that BPMFs averaged over a holo ensemble yield binding free energies relative to the reference ligand that specifies the ensemble. When using receptor snapshots from an alchemical simulation with a single ligand, the new statistical estimator outperforms the original.
Quantifying spot size reduction of a 1.8 kA electron beam for flash radiography
Authors: Burris-Mog T. J. , Moir D. C.
Published: March 2018

The spot size of Axis-I at the Dual Axis Radiographic Hydrodynamic Test facility was reduced by 15.5% by including a small diameter drift tube that acts to aperture the outer diameter of the electron beam. Comparing the measured values to both analytic calculations and results from a particle-in-cell model shows that one-third to one-half of the spot size reduction is due to a drop in beam emittance. We infer that one-half to two-thirds of the spot-size reduction is due to a reduction in beam-target interactions. Sources of emittance growth and the scaling of the final focal spot size with emittance and solenoid aberrations are also presented.
Estimating single molecule conductance from spontaneous evolution of a molecular contact
Authors: Gil M. , Malinowski T. , Iazykov M. , Klein H. R.
Published: March 2018

We present an original method to estimate the conductivity of a single molecule anchored to nanometric-sized metallic electrodes, using a Mechanically Controlled Break Junction operated at room temperature in the liquid. We record the conductance through the metal/molecules/metal nanocontact while keeping the metallic electrodes at a fixed distance. Taking advantage of thermal diffusion and electromigration, we let the contact naturally explore the more stable configurations around a chosen conductance value. The conductance of a single molecule is estimated from a statistical analysis of raw conductance and conductance standard deviation data for molecular contacts containing up to 14 molecules. The single molecule conductance values are interpreted as time-averaged conductance of an ensemble of conformers at thermal equilibrium.
AC and DC electrical behavior of MWCNT/epoxy nanocomposite near percolation threshold: Equivalent circuits and percolation limits
Authors: Alizadeh Sahraei Abolfazl , Ayati Moosa , Baniassadi Majid , Rodrigue Denis , Baghani Mostafa , Abdi Yaser
Published: March 2018

This study attempts to comprehensively investigate the effects of multi-walled carbon nanotubes (MWCNTs) on the AC and DC electrical conductivity of epoxy nanocomposites. The samples (0.2, 0.3, and 0.5 wt. % MWCNT) were produced using a combination of ultrason and shear mixing methods. DC measurements were performed by continuous measurement of the current-voltage response and the results were analyzed via a numerical percolation approach, while for the AC behavior, the frequency response was studied by analyzing phase difference and impedance in the 10 Hz to 0.2 MHz frequency range. The results showed that the dielectric parameters, including relative permittivity, impedance phase, and magnitude, present completely different behaviors for the frequency range and MWCNT weight fractions studied. To better understand the nanocomposites electrical behavior, equivalent electric circuits were also built for both DC and AC modes. The DC equivalent networks were developed based on the current-voltage curves, while the AC equivalent circuits were proposed by using an optimization problem according to the impedance magnitude and phase at different frequencies. The obtained equivalent electrical circuits were found to be highly useful tools to understand the physical mechanisms involved in MWCNT filled polymer nanocomposites.
Thermally and optically tunable lasing properties from dye-doped holographic polymer dispersed liquid crystal in capillaries
Authors: Chen Maozhou , Dai Haitao , Wang Dongshuo , Yang Yue , Luo Dan , Zhang Xiaodong , Liu Changlong
Published: March 2018

In this paper, we investigated tunable lasing properties from the dye-doped holographic polymer dispersed liquid crystal (HPDLC) gratings in capillaries with thermal and optical manners. The thermally tunable range of the lasing from the dye-doped HPDLC reached 8.60 nm with the temperature ranging from 23 °C to 50 °C. The optically tunable laser emission was achieved by doping azo-dye in HPDLC. The transition of azo-dye from trans- to cis-state could induce the reorientation of LC molecules after UV light irradiation, which resulted in the variation of refractive index contrast of LC-rich/polymer-rich layer in HPDLC. Experimentally, the emission wavelength of lasing showed a blueshift (about 2 nm) coupled with decreasing output intensities. The tunable laser based on HPDLC may enable more applications in laser displays, optical communication, biosensors, etc.
Onset of fast “ideal” tearing in thin current sheets: Dependence on the equilibrium current profile
Authors: Pucci F. , Velli M. , Tenerani A. , Del Sarto D.
Published: March 2018

In this paper, we study the scaling relations for the triggering of the fast, or “ideal,” tearing instability starting from equilibrium configurations relevant to astrophysical as well as laboratory plasmas that differ from the simple Harris current sheet configuration. We present the linear tearing instability analysis for equilibrium magnetic fields which (a) go to zero at the boundary of the domain and (b) contain a double current sheet system (the latter previously studied as a Cartesian proxy for the m = 1 kink mode in cylindrical plasmas). More generally, we discuss the critical aspect ratio scalings at which the growth rates become independent of the Lundquist number S, in terms of the dependence of the Δ′ parameter on the wavenumber k of unstable modes. The scaling Δ′(k) with k at small k is found to categorize different equilibria broadly: the critical aspect ratios may be even smaller than L/a ∼ Sα with α = 1/3 originally found for the Harris current sheet, but there exists a general lower bound α ≥ 1/4.
The boundary degeneracy of a nonlinear equation related to electrorheological fluid
Authors: Si Xin , Zhan Huashui , Yuan Hongjun
Published: March 2018

The well-posedness of the solutions to the general electrorheological fluid equation is studied when the diffusion coefficient is degenerate on the boundary. It is shown that the solutions of the equation may be controlled by the initial value completely, and the usual Dirichlet boundary condition may be superfluous.
Effect of precipitates on properties of cold-rolled Al–Mg–Si–Sc–Zr alloy with higher temperature aging
Authors: Li Ming , Li Heng , Zhang Zhen , Shi Wenchao , Liu Jiaqin , Hu Yue , Wu Yucheng
Published: March 2018

The aging hardening behaviours of the cold-rolled Al–Mg–Si–Sc–Zr alloy were investigated. The microstructure, hardness and electrical conductivity (EC) of the Al–Mg–Si–Sc–Zr alloy were measured. The relationship between the microstructure and the properties of the Al–Mg–Si–Sc–Zr alloy with cold-rolling and aging processes was studied. The result shows that the addition of Sc and Zr elements significantly refines the grains of the Al–Mg–Si alloy during casting. The cold rolling promotes the Al–Sc(Zr) precipitation. The precipitate strengthening increases with increasing roll reduction. The EC of the cold rolling + aging Al–Mg–Si–Sc–Zr alloy increases with increasing rolling reductions. The combination effects of the precipitation hardening and DRX softening during the aging process lead to the similar peak hardness values of around 70 HV of the rolled Al–Mg–Si–Sc–Zr alloy with the different reductions.
Seeing double: design and enactments of a lesson on perspective‐taking
Authors: Ott Mary , MacAlpine Kelly-Ann , Hibbert Kathryn
Published: March 2018

This narrative inquiry of a lesson intended to develop perspective‐taking links our understanding of teachers as curriculum makers with a sociomaterial attunement to the ways that materials, forms, and time are also actors in producing curriculum. We offer a close reading of three classroom enactments of the same lesson and discuss ways that these instances of curriculum‐making expanded or diminished opportunities for elementary pupils to communicate shifts in perspective through personal narrative writing. We find temporal, spatial, and material resources, including schedules, technologies, and forms of assessment, to play key roles in shaping relations in curriculum making.
Transmission of integrin β7 transmembrane domain topology enables gut lymphoid tissue development
Authors: Sun Hao , Lagarrigue Frederic , Gingras Alexandre R. , Fan Zhichao , Ley Klaus , Ginsberg Mark H.
Published: March 2018

Integrin activation regulates adhesion, extracellular matrix assembly, and cell migration, thereby playing an indispensable role in development and in many pathological processes. A proline mutation in the central integrin β3 transmembrane domain (TMD) creates a flexible kink that uncouples the topology of the inner half of the TMD from the outer half. In this study, using leukocyte integrin α4β7, which enables development of gut-associated lymphoid tissue (GALT), we examined the biological effect of such a proline mutation and report that it impairs agonist-induced talin-mediated activation of integrin α4β7, thereby inhibiting rolling lymphocyte arrest, a key step in transmigration. Furthermore, the α4β7(L721P) mutation blocks lymphocyte homing to and development of the GALT. These studies show that impairing the ability of an integrin β TMD to transmit talin-induced TMD topology inhibits agonist-induced physiological integrin activation and biological function in development.
Walking Aid Use in Canada: Prevalence and Demographic Characteristics Among Community-Dwelling Users
Authors: Charette Caroline , Best Krista L , Smith Emma M , Miller William C , Routhier François
Published: March 2018

Background

Mobility limitations represent the third most prevalent cause of disability, affecting more than 1.9 million community-dwelling Canadians. Walking aids are often prescribed to reduce the impacts of mobility impairments. There are limited data on walking aids since 2004.

Objective

The objectives of this study were to investigate the prevalence of walking aid use in Canada and to explore demographic characteristics among users of walking aids.

Design

The design used was a secondary analysis of a cross-sectional national survey.

Methods

Data were obtained from the 2012 Canadian Survey on Disability from community-dwelling individuals who were 15 years old or older, had a self-identified activity limitation, and indicated that they used at least 1 walking aid (cane/walking stick/crutches or walker). Prevalence estimates were calculated as weighted frequencies. Analytic variables included walking aid type, sex, age, province/territory of residence, and main cause of activity limitation.

Results

Approximately 1,125,000 community-dwelling individuals who were 15 years old or older used walking aids, representing 4.1% of the Canadian population. Of these individuals, 962,290 used canes/walking sticks/crutches, and 465,340 used a walker. Users of walking aids were predominantly female, with a mean age of 68 years.

Limitations

Self-reported results reflect only the perceptions of individuals living in Canadian communities. Analyses excluded individuals in residential or long-term care settings and individuals living on First Nations reserves.

Conclusions

Since 2004, there has been a 2% increase in the prevalence of walking aid use by the Canadian population, which is likely related to the aging of the population. The high prevalence of walking aid use highlights the need for better use of existing resources to ensure that individuals are receiving the correct devices. Results of this study suggest a need to evaluate the impact of device use to better understand how resources should be allocated for prescription and maintenance of walking aids and training of users.