bluuebunny/crossref_metadata_2025 huggingface dataset:
The Residual Thickness Calculation of Fan Blades Based on the Resistance Network Mathematic Model
Authors: Chen Dian Bin , Ma Jun Ying , Wang Xi Liang , Han Dong Fei , Li Hong Wei
Published: November 2018

According to the situation of the core parts fan blades are susceptible to sand dust particles, and high speed collision can generate wear corrosion, the current field change before and after, the corrosion is the main cause of pitting corrosion precision error. Through the FSM method analysis of the monitoring area, the residual thickness of pitting corrosion was calculated by the mathematical model of resistor network. The finite element analysis and experimental results are consistent.
Atomic Force Microscopy Measurements of the Area Function of a Sphero-Conical Tip
Authors: Charvátová Campbell Anna , Šlesinger Radek , Klapetek Petr , Buršíková Vilma
Published: November 2018

With the improvement of depth-sensing instruments nanoindentation has become a standard tool for the study and design of thin film systems, nanocomposites and other nanostructured materials and devices. Mechanical properties, such as elastic modulus and hardness can be measured at scales in the depth range of tens of nanometers. The correct determination of the mechanical properties depends on the proper evaluation of the real contact area. While two standard methods are commonly used, indentations on a reference sample and measurement by atomic force microscopy (AFM), there are many caveats and the issue remains tricky, especially for large depths. In this contribution we present an example where the standard calibration of the tip area function via a reference sample cannot be used for the desired tip and the AFM method must be used instead.
Oxide Ceramic Nano/Microfibers Prepared by Needle-Less Electrospinning - Materials for Fiber Reinforced Composites
Authors: Shepa Ivan , Mudra Erika , Vojtko Marek , Podobova Maria , Dusza Jan
Published: November 2018

Nano/microfibers are already widely used as the reinforcements in various types of advanced composites for reducing weight, improving specific properties like hardness, fracture toughness and other mechanical ones. This contribution describes the preparation of the titanium dioxide nano/microfibers by needle-less electrospinning, along with a detailed characterization of the obtained polycrystalline ceramics. For spinning solutions preparation the polyvinylpyrrolidone (PVP), titanium isopropoxide (TTIP), ethanol and acetic acid were used. Influence of the ceramic precursor concentration in the spinning solution showed that decreasing the concentration of TTIP from 30 to 10 wt.% has no effect on the precursor polymer fibers shape. However, it causes deviation from the fibers oval shape (in the cross-section) up to the formation of solid ribbons or even multilayered porous ribbons. Heat treatment temperature defined the phase composition of the obtained oxide ceramics – stabile polycrystalline rutile fibers were obtained at 600 °C.
Comparison Study of Internal Stress Measured by Diffraction Mapping and Calculation Using FEM
Authors: Gamcová Jana , Milkovič Ondrej , Németh Dušan , Mohanty Gaurav , Michalik Štefan , Wehrs Juri , Bednarčík Jozef , Krywka Christina , Breguet Jean-Marc , Michler Johann , Sovák Pavol , Franz Hermann
Published: November 2018

The measuring of internal stress has not only a great scientific aspect, but is particularly important for nondestructive description of component or products in industry. It is expected that exceeding of local mechanical limits in the material can have catastrophic consequences. In this paper is mapped the deformation field of amorphous material under the nanoindenter tip using diffraction in Debye-Scherrer geometry. Using the FEM analysis, it was modeled the deformation field in such material. There is a great match in between measured and calculated data. The result is pointing out on large limits of internal stresses measuring by conventional standard methods.
Mechanical Properties of HVOF Sprayed CrC-NiCr Coating Exposed to Hot Corrosion Environment
Authors: Schubert Jan , Česánek Zdeněk , Bláhová Olga
Published: November 2018

Current development in power generation industry leads to search of new technologies and ways how to protect surface against aggressive corrosion environment. Suitable method leading to enhancement of surface properties is application of protective coatings on surface. This approach allows to use components composed from less quality materials. The current development in steam turbines leads to increasing operating temperatures for the purpose to enhance performance. This process results in elevation of operating temperature reaching the potential limits of commonly used materials. One of the key areas of protection in such environment is protection against hot temperature corrosion. Possible solution can be found in application of coatings based on alloys and cermets prepared by HVOF (High Velocity Oxygen Fuel) technology. This paper examines local mechanical and microstructural properties of Cr3C2-25%NiCr coating after exposition to extremely severe hot corrosion environment. Furthermore, the nanoindentation measurements of this coating were performed before and after the corrosion test. The test environment composition was based on mixture of salts 59% Na2SO4 with 34.5% KCl and 6.5% NaCl. Test temperature was 525°C and 575°C. Duration of the exposition to hot corrosion environment was 168 hours in autoclave. The results confirmed that the coating matrix is deteriorated during the exposition to such aggressive environment. The deterioration is localized at surface of coating and is characterized by creation of oxide layer which decreases the speed further speed of matrix dissolution and stabilizes the coating.
Microstructure and Micromechanical Properties of Mg Microtubes Prepared by Laser Dieless Drawing
Authors: Jäger Aleš , Tesař Karel , Němeček Jiří , Milenin Andrij , Němeček Jiří
Published: November 2018

The paper presents microscale experimental investigation performed on microtubes that were prepared with a novel laser dieless drawing (LDD) technique from difficult-to-work AZ31 magnesium alloy (nominally 3wt.%Al-1wt.%Zn-0.3wt.%Mn-Mg balanced). A microstructure analysis was performed via various microscopic techniques. Mechanical response of individual grains with various orientations was tested using instrumental nanoindentation and the results were compared with the microstructure. Distributions of elastic modulus, hardness and visco-elastic properties were analyzed. In addition, microtubes were also characterized in terms of their surface roughness and morphology based on different modes of surface treatment. The grain size is practically not changed when LDD is applied after extrusion showing low thermal and straining effect of the process. Local mapping of mechanical properties does not show weak spots and imply feasibility of the novel production technology.
Fracture Properties of Cement Studied by Nanoindentation and FIB
Authors: Němeček Jiří , Němeček Jiří , Maňák Jan
Published: November 2018

The paper shows results of microscale experimental tests performed on cement paste specimens fabricated by focused ion beam milling. The specimens are prepared in the form of cantilever beams and loaded in bending by nanoindenter. The dimensions of specimens are in the order of a few micrometers which corresponds to the single phase size. Intact and notched specimens with a stress concentrator are tested. Tensile strength and fracture energy are derived for the hydration product by analyzing the nanoindentation data and with the aid of analytical and numerical modeling. Although small number of tests is performed good correlation of the results is reached with respect to the available literature and molecular dynamic simulations.
Indentation Measurement of CuZnAl Dual Phase Shape Memory Alloy
Authors: Vojtko Marek , Balko Ján , Fides Martin , Vojtkova Liudmila
Published: November 2018

The aim of this work is indentation study of local mechanical properties of Cu-22Zn-4.6Al alloy, which has significant shape memory effect after quenching from dual α + β phase region. The study was carried out on the samples with thermoelastic and non-thermoelastic martensite in the structure, which were obtained by quenching from various temperatures. A different behavior concerning mechanical properties measurements of α phase and β phase transformed to martensite after quenching from various temperatures was found out. It was observed almost no change of mechanical properties of α phase, whereas indentation hardness HIT and indentation modulus EIT raised with increasing quenching temperature. Also some serious differences were observed at indentation test of thermoelastic and non-thermoelastic martensite.
Effect of Pyrolysis Temperature on the Mechanical Response in Partially Pyrolysed Polysiloxanes
Authors: Halasová Martina , Černý Martin , Strachota Adam , Chlup Zdeněk
Published: November 2018

The pyrolysis process of polysiloxane resin conducted in the temperature range 400 – 700 °C results in hybrid materials owning some polymeric (thermosetting) behaviour. A certain level of elastic recovery and/or viscoelastic flow showed at various steps of pyrolytic transformation was monitored using the instrumented Vickers hardness method. Determined indentation force-indentation depth curves reflect the mechanical response and the level of the transformation; however, the relaxation behaviour is not covered by this method fully. An extensive indentation relaxation was revealed in the material partially pyrolysed at 400 °C, about 16 % and 8 % when the HV 0.1 and the HV 0.2 loading were applied, respectively. Materials pyrolysed from 500 to 650 °C which exhibited the indentation relaxation below 1 % and the mostly elastic response on the loading were observed. Above the pyrolysis temperature of 600 °C a rapid onset of mechanical properties, namely indentation elastic modulus and hardness, was observed. The short-term indentation relaxation was evaluated via the indentation force relaxation method in the regime of constant indentation depth obtained at the moment of reaching an initial force of 0.981 N or 1.962 N. The obtained indentation force relaxation curves were analysed on the basis of a logarithmic function. The significant effect of the pyrolysis temperature as well as the influence of loaded volume was described.
Study of Alumina and Alumina-Silicon Carbide Layered Composite Sintered by SPS
Authors: Drdlík Daniel , Mařák Vojtěch , Roleček Jakub , Drdlíková Katarína , Kratochvíl Jiří , Salamon David
Published: November 2018

A laminate composed from alumina and mixture of alumina and 5 vol.% of SiC as well as standards with composition of each layer were prepared using a slip-casting method for green body preparation with following spark plasma sintering. The laminate had a sharp interface between layers and no delamination was observed. Prepared materials were characterized in terms of their microstructure, hardness and fractographic analysis. Because of supposed ballistic potential all prepared ceramics were also subjected to depth of penetration testing.
Numerical Stress Analysis of the Biaxial Tension-Compression Wedge-Splitting Test in Vicinity of the Crack Tip
Authors: Seitl Stanislav , Miarka Petr , Merta Ildikó , Keršner Zbyněk
Published: November 2018

Wedge-splitting test is widely used fracture mechanical test for its stability in measurement during the testing and many papers were published. However, the biaxial wedge-splitting test is relatively a new method and the numerical stress analysis of such test is necessary. Especially the investigation of the stress fields in the vicinity of the crack tip. In this contribution, influence of various biaxial stress level is discussed on values of first and second terms of William’s expansion.
Microstructure and Local Mechanical Properties of Skutterudites with Addition of Metallic Borides
Authors: Buršík Jiří , Buršíková Vilma , Rogl Gerda , Rogl Peter
Published: November 2018

Skutterudites are an important class of thermoelectric p- and n-type materials and they have already achieved fair efficiencies for the conversion of heat to electricity. Nevertheless researchers try to further enhance the figure of merit, ZT, by various ways. In this work we study microstructure and mechanical properties of two thermoelectric materials: an industrial n-type (Mm,Sm)yCo4Sb12 skutterudite and an industrial p-type DDyFe3CoSb12 skutterudite, both mixed with 1 wt.% of Ta0.8Zr0.2B. Thin lamellae were prepared from the compacted materials using a focused ion beam. Analytical transmission electron microscopy was used on lamellae to study details of microstructure. A fine dispersion of precipitates was found both at nanograin boundaries and in their interiors. Quasistatic and dynamic nanoindentation tests were carried out on planar polished sections in the range of applied loads from 0.01 to 10 mN. The results were complemented with quantitative modulus mapping of local mechanical properties with 10-nm resolution.
Detailed Approach to Planning Transfers from One Production Facility to Another
Authors: Aleksandrov Vadim , Kadyrov Marsel , Ponomarev Andrey , Drugov Denis , Bulgakova Irina
Published: November 2018

The modern state of the raw material base of the “Kogalymneftegaz” TMC is characterized by deterioration in the structure and quality of the field reservoirs at the latter development stage. The depletion of the main developed oil formations has long exceeded 60%. Despite the high depletion rate, the complete coverage of all recoverable resources by flooding has not been achieved. The differences in zone and area irregularities of the production facilities and the imperfection of the existing development systems at the present stage lead to the formation of non-drainable resources. In order to involve them into production in formations, various types of interventions are carried out in order to improve the existing development systems. The research objective is to develop a detailed approach to planning a transfer of wells which have completed their purpose from one development facility to another. Using a detailed geological and routine analysis of results of carrying out various interventions on the formation, an active application of the most effective of these has been proposed.
Oil and Gas Reef Facies Reservoir 3D Geological Modeling
Authors: Aleksandrov Vadim , Kadyrov Marsel , Ufelman Zinaida , Golozubenko Vadim , Kopyrin Vladimir
Published: November 2018

The paper presents a technique of three-dimensional geological modeling of one of the most complex formations, reef deposits. The research objective is an investigation of how the reef structure genesis influences the three-dimensional geological grid of reef mass. Using the paleogeographic and paleofacies methods of investigation, the conceptual and three-dimensional geological models of a natural reservoir have been constructed.
Genetic Zoning of the YUV1 Productive Horizon Deposits within the Tagrinsko-Yarainersky Bar
Authors: Aleksandrov Vadim , Kadyrov Marsel , Ponomarev Andrey , Galinskij Kirill , Aleksandrov Sergey
Published: November 2018

The developed litho-sedimentological model of deposits of the YUV1productive horizon makes it possible to choose the most effective technique for supplementary exploration of a natural reservoir and improve the quality of geological justification for its subsequent development. The research objective is to carry out paleogeographic and paleostructural reconstructions, to identify facies complexes in the Upper Jurassic productive deposits, and to identify zones for the development of improved reservoir units. With the help of paleogeographic and facies methods, the geological regularities of the development of the territory encompassing the Tagrinsko-Yarainersky Bar in the Late Callovian-Oxfordian Stage were studied.
Refinement of the Geologic Structure of the Ozernoye Field for Improving the Development Efficiency
Authors: Aleksandrov Vadim , Kadyrov Marsel , Ponomarev Andrey , Drugov Denis , Zavatskij Mikhail
Published: November 2018

The Ozernoye field is a unique geological object. The primary geological and geophysical materials obtained during its inspection allow coming close to developing universal methods for carbon-containing field logging, which can be extended to other geological objects. The research objective is to forecast the development of reservoir units in undeveloped parts, determine the expected parameters of their class, the maximum total net reservoirs and the number of sandy formations, carry out their indexation and detailed paleogeographic reconstructions of the inspected area. Using the paleogeographic methods, retrospective reconstructions of sedimentation accumulations were performed. The facies analysis of sediments made it possible to elucidate the reservoir unit genesis.
Application of Lithofacies Modeling for Evaluating the Effectiveness of Enhanced Oil Recovery in the Fainsk Oil Field
Authors: Aleksandrov Vadim , Kadyrov Marsel , Ponomarev Andrey , Drugov Denis , Veduta Olga
Published: November 2018

A lithofacies model of the Fainsk oil field YUS11 formation was built. The results of interventions for oil production stimulation and enhanced oil recovery depending on the section penetrated by wells were considered. Criteria for selection of various types of interventions in particular geophysical conditions were given, and recommendations on the selection of technologies for bottomhole zone processing (BZP) and enhanced oil recovery (EOR) were made. The research objective is to evaluate the effectiveness of interventions in terms of enhanced oil recovery, adapted to the specific features of the field geologic structure aspects. Through the use of sedimentary deposits facies analysis method, a lithofacies model of the Fainsk oil field YUS11 formation was constructed. The application of field-geologic analysis gave an option to evaluate the technological effectiveness of interventions for oil production stimulation and enhanced oil recovery depending on the reservoir units genesis penetrated by wells.
Analysis of the Geological Structure of the Sredne-Ugutskoye Oil Field with Regard to an Increase in the Efficiency of its Development
Authors: Aleksandrov Vadim , Kadyrov Marsel , Ponomarev Andrey , Drugov Denis , Bulgakova Irina
Published: November 2018

The productive formations YUS11 and YUS12 are characterized by a strong lithologic and facies instability. The article shows the results of the analysis of the geological and technical interventions efficiency carried out on these sediments and defines their genetic dependence on the specific features of geological structure. The research objective is to analyze the geological structure of productive deposits, identify facies complexes and assess the effectiveness of geological and technical interventions. With the help of geological-field analysis, a quantitative evaluation of the technological effect obtained during the hydraulic fracturing of well formations, the repair and insulation works and a whole range of measures on intensification of inflow was carried out.
Magnetocaloric Effect of Ni44Co6Mn40CuxSn10-x Quinary Alloy Comes from the Martensitic Transformation
Authors: Guo Zhen Gang , Qiu Hong Mei
Published: November 2018

The structure, martensitic transition and magnetic properties of Ni44Co6Mn40CuxSn10-x quinary alloy are investigated systematically. The substitution of Cu for Sn is found to reduce the symmetry of crystal structure, showing an evolution from cubic to tetragonal phase at room temperature. Two magnetic transitions were observed in the alloys, martensitic transition and Curie transition. The critical temperatures of martensitic transformation are found to increase nearly linearly with increasing valence electron concentration caused by Cu substitution for Sn, while Curie temperature of the austenitic phase decreases with the increasing Cu content in the alloys. The Ni44Co6Mn40CuxSn10-x alloys have a large magnetic entropy change across the martensitic transition, reaching 26.8 Jkg-1K-1 under a field change of 3T, because of the strong coupling between structure and magnetism, which shows a great applicable prosperity in magnetic refrigeration technology.
V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate
Authors: Wang Huan You , Tan Qiao Lai , Jin Gui
Published: November 2018

InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.
The Unique Property in Magnetic Noise of Spin Modulated Atomic Magnetometer
Authors: Wang Xiao Fei , Li Ji Min
Published: November 2018

This paper presents a spin modulated atomic magnetometer, different from other kinds of atomic magnetometers, the conversion coefficient between the polarization signal and the magnetic field to be measured is independent of the transverse relaxation time, which means that the higher sensitivity can be achieved when polarization is kept constant. For better understanding, the magnetic noise of spin modulated magnetometer is demonstrated and compared to SERF magnetometer. The magnetic noise measurement experiment is designed, the experimental results are consistent with the theoretical prediction. This paper validate the unique property of spin modulated magnetometer and this property will play an important role in guiding the optimization of future experiments.
Features of Regularities of Ni3Al Intermetallic Compound High-Temperature Synthesis in a Powder Mixture (3Ni + Al) under Pressure
Authors: Akimov K.O. , Boyangin E.N. , Ovcharenko Vladimir E.
Published: November 2018

The results of investigation of the time and power parameters influence of high-temperature synthesis under pressure on the grain structure formation and strength properties of the Ni3Al intermetallic compound are presented and discussed. Dependences of the grain size in the intermetallic compound synthesized under pressure and its strength properties on the value of the preload on the initial powder mixture (3Ni + Al) and on the delay time of pressure application to the thermoreacting system were determined from the time of initiation of intermetallic compound formation volumetric exothermic reaction.
Speckle Pattern of the Surface Layer of Titanium Alloy GRADE 2 and Steel 3723HR Samples under Deformation
Authors: Ustinov A.M. , Klimenov Vacily A. , Klopotov A.A. , Abzaev Yu.A. , Ovcharenko Vladimir E.
Published: November 2018

The deformation behavior during tension of titanium GRADE 2 and steel 3723HR samples is investigated. The distribution of localized plasticity foci in the near-surface layers of samples of two materials is studied. A correlation between the stages on deformation curves and evolution patterns of spatial localized plasticity foci on titanium alloy GRADE 2 and steel 3723HR is established. It is established that a different type of deformation diagrams σ=f (ε)) during tension of metallic materials is manifested in the different distribution character of deformation fields at different stages of the deformation curve.
Metal Control of Operated and Damaged Situated Parts and Welded Wire Connections
Authors: Ababkov Nikolai V. , Smirnov Alexander N. , Pimonov Maksim V. , Levashova Elena E.
Published: November 2018

Investigation of the metal of exploited and damaged bends of water and steam-removing pipes by the spectral-acoustic control method and by the method of electron microscopy was carried out in the work. A sample without damages, a specimen with a corrosion-fatigue crack and a sample with a technological sunset type defect were investigated. Graphic dependencies of acoustic characteristics on the time of operating time are constructed. The values of the acoustic characteristics corresponding to the defective state for the metal of the bends of the water and steam-removing pipes have been established.
New Developments to Reduce Arc Blow during SMAW of Pipelines
Authors: Baklanov Sergey V. , Gordynets Anton S. , Kiselev A.S. , Slobodyan Mikhail S.
Published: November 2018

In some cases, magnetic blow does not allow using direct current for shielded metal arc welding. This is especially true for repair work on pipelines after magnetic flaw detection. Alternating current is useful to control magnetic arc blow during welding. The most promising results give technologies using alternating current with a rectangular waveform. However, the advantages of this method have not been used until now. The main goal of this study is to determine the influence of the parameters of the arc on its stability and the metal transfer mode during shielded metal arc welding under perturbing action of the magnetic field. The proposed methodology of experimental research allowed identifying the cause of arc extinction using direct current electrode positive. This is due to displacement of molten droplets of metal by the magnetic field from of the uneven melted electrode coating and its subsequent separation. This problem was solved using alternating current with the square waveform pulse mode at a frequency of 500 Hz. The amplitude-time parameters of the current pulses provide stabilization of the arc and volume of the molten electrode metal.
Long-Term Outcomes of a Simulation-Based Remediation for Residents and Faculty With Unprofessional Behavior
Authors: Guerrasio Jeannette , Aagaard Eva M.
Published: November 2018

Background

There are few studies describing remediation for unprofessional behavior in residents and faculty and none that assess the long-term impact of remediation.

Objective

We implemented a simulation-based personalized remediation program for unprofessional behavior in residents and faculty and collected assessments from participants and referring supervisors.

Methods

Residents and faculty were referred for unprofessional behaviors, including aggressive, condescending, and argumentative communication styles as well as an inability to read social cues. We had standardized patients recreate the scenarios that triggered the unprofessional behavior. After each scenario, participants reviewed a videotape of their performance, participated in guided self-reflection and feedback, and then iteratively practiced skills. In 2017, about 2 to 4 years after the intervention, we conducted structured phenomenological qualitative interviews until thematic saturation was reached. Transcripts were analyzed inductively for themes by 2 reviewers (J.G. and research assistant).

Results

Requests for interviews were sent to 16 residents, 8 faculty members, and 24 supervisors, including program directors. Nine remediation participants (38%) and 19 referring supervisors (79%) were interviewed. Sixteen supervisors reported no recurrence of unprofessional behavior in participants 2 to 4 years after the intervention, and participants identified behavioral strategies to reduce unprofessional behavior. Participants and respective supervisors reported similar themes of behavior changes that resulted in improved professional interaction with others.

Conclusions

A simulation-based personalized remediation program for unprofessional behavior, where faculty and residents practice behaviors with guided feedback, can lead to sustained positive behavior change in participants.
A new manual wheelchair propulsion system with self-locking capability on ramps
Authors: Jiménez Gaspar Rodríguez , Salgado David Rodríguez , Alonso Francisco Javier , del Castillo José María
Published: November 2018

Abstract. A wheelchair user faces many difficulties in their
everyday attempts to use ramps, especially those of some length. The present
work describes the design and build of a propulsion system for manual
wheelchairs for use in ascending or descending long ramps. The design is
characterized by a self-locking mechanism that activates automatically to
brake the chair when the user stops pushing. The system consists of a
planetary transmission with a self-locking capacity coupled to a push rim
with which the user moves the system. Different transmission ratios are
proposed, adapted to the slope and to the user's physical capacity (measured
as the power the user can apply over ample time periods). The design is
shown to be viable in terms of resistance, and approximate dimensions are
established for the height and width of the propulsion system. Also, a
prototype was built in order to test the self-locking system on ramps.
The effect of workplace relocation on individuals’ activity travel behavior
Authors: Sprumont Francois , Viti Francesco
Published: November 2018

On working days, homes and workplaces can be seen as anchor locations at the heart of daily mobility patterns, as well as being central to an employee’s activity pattern. In this study, we investigate how workplace relocation affects the entire daily activity-travel chain. While past research has shown that workplace decentralization is often associated with higher car use for the commuting trip, little is known about the effect on the whole activity travel pattern. Two waves of a two-week travel diary were completed by 43 employees of the University of Luxembourg: one before and one after the relocation of their office. Using descriptive statistics as well as standard deviational ellipses (SDE) theory combined with the results of a clustering analysis showed that workers’ activity spaces (represented by the standard deviational ellipses) were significantly modified due to the relocation of a single anchor activity location, i.e., their workplace.
The mystery of the digital natives' existence: Questioning the validity of the Prenskian metaphor
Authors: Sorrentino Pasqualina
Published: November 2018

Net Generation (Tapscott, 2009, 1998; Oblinger and Oblinger, 2005), Generation Y (Zhao and Liu, 2008; Halse and Mallinson, 2009), Millennials (Howe and Strauss, 2000), Homo Zappiens (Veen, 2003) and i-Generation (Rosen, 2010). The labels used to describe the generation of young people and their relation with technology are numerous. Over the past few years, one of the notions, which might have had more echoes among parents, teachers, and policy-makers is those of “digital natives” introduced in 2001 by Mark Prensky. The metaphor has had enduring influence on how the educational system perceives students and technology. Most scholars do not like it, for various reasons. Among other problems, the term implies that technological abilities are innate rather than taught and learned. The aim of this contribution is not to join the existing debate about the existence of digital native but to examine if there is any empirical evidence to support the use of that metaphor in the first place, questioning its usefulness to depict particular generations of young people.
Decreasing materiality from print to screen reading
Authors: Schilhab Theresa , Balling Gitte , Kuzmičová Anežka
Published: November 2018

The shift from print to screen has bodily effects on how we read. We distinguish two dimensions of embodied reading: the spatio-temporal and the imaginary. The former relates to what the body does during the act of reading and the latter relates to the role of the body in the imagined scenarios we create from what we read. At the level of neurons, these two dimensions are related to how we make sense of the world. From this perspective, we explain how the bodily activity of reading changes from print to screen. Our focus is on the decreased material anchoring of memories.
Children learning to read in a digital world
Authors: Barzillai Mirit , Thomson Jenny M.
Published: November 2018

Children’s earliest experiences of written language increasingly involve digital text — on phones, tablets and computers. This shift has triggered worry about the potential harm to children’s ability to read in a deep, focused manner on the one hand, and optimism for the potential of technology to support reading among different groups on the other.In this article, we explore research evidence concerning the impact of digital text on children’s developing literacy skills. Our review advocates the need for a more nuanced understanding regarding the challenges and potential of digital environments and highlights the uniqueness of each child’s digital reading experience.
Reading in the era of digitisation: An introduction to the special issue
Authors: Kovač Miha , Van der Weel Adriaan
Published: November 2018

Digital technologies offer tremendous opportunities with respect to information access, storage and transmission, and digital reading environments offer ways to present information that are difficult or impossible to attain in text on paper. This is significantly changing the ways we read. Digital materials can be adapted to each individual’s skill level, enabling flexible learning processes to accommodate the particular needs and developments of each reader. At the same time, empirical research indicates that the affordances of screens may also foster less advantageous reading developments, habits and mind sets.This warrants balancing the discourse on possibilities and advantages of digital technologies. To this purpose ‘Evolution of Reading in the Age of Digitisation’ (E-READ) — a research initiative funded by COST (European Cooperation in Science & Technology) as Action IS1404 — has brought together almost 200 scholars and scientists of reading, publishing, and literacy from across Europe. Starting from the assumption that the introduction of digital technologies for reading are not neutral regarding cognition and comprehension, the members of the network joined in an effort to research how readers, and particularly children and young adults, comprehend or remember written text when using print versus digital materials.The articles in this special issue have been written by members of the EW-READ network to discuss indepth way a number of findings, hypotheses and recommendations that came out of their research about print versus screen reading.
Reddit as a new platform for public relations: Organizations' use of dialogic principles and their publics' responses in the subreddit IAmA
Authors: Le Phuong Hoan , Mao Yuping
Published: November 2018

Applying Kent and Taylor’s (2002) dialogic communication framework, this study aims to explore in what ways organizations implement dialogic principles in the subreddit IAmA, a specific section of Reddit. This study also focuses on the less-researched publics’ side of computer-mediated PR. Twenty-three threads were purposively selected within the year-long timeframe of 1 February 2014 until 1 February 2015, including 40,903 comments of which 1,482 are responses from organizations. A qualitative content analysis was applied. The findings suggest that there is room for improvement in organizations’ use of dialogic principles and highlight the complexity of audience responses. While each dialogic principle can be argued to theoretically have a positive effect on these responses, audiences on Reddit especially hold transparency, open communication, and honesty in high regard and expect organizations’ threads to have extrinsic and/or intrinsic value for the publics besides having value for the organization in marketing and PR context.
Eating (alone) with Facebook: Digital natives' transition to college
Authors: Park Giyoung
Published: November 2018

This study explores how communication patterns in social settings are related to one’s transition to a new environment, and what and how contextual variables are associated with these patterns. An exploratory, qualitative phase included interviews, focus groups, and anonymous confession posts on Facebook, followed by three quantitative online surveys using college freshman students during their initial semester. Dormitory dining halls were among primary social settings on campus; yet, freshman students did not want to eat dinner alone there. Dinner location was not correlated with sense of belonging; however, underrepresented minority (URM) who had dinner in dormitory dining halls reported lower sense of belonging. URM solo-diners more likely used screens. Solitary URM diners who used a screen in the dining hall reported lower sense of belonging early in the initial semester. Text messaging in the dining halls was associated with greater sense of belonging. Furthermore, greater sense of belonging was related to better mental health. URMs’ greater sense of belonging in the initial semester could predict greater academic achievement over the next few semesters.
How social media supports hashtag activism through multivocality: A case study of #ILookLikeanEngineer
Authors: Malik Aqdas , Johri Aditya , Handa Rajat , Karbasian Habib , Purohit Hemant
Published: November 2018

Although research on different hashtag activism campaigns abounds, no study has looked at how different affordances of social media support a single campaign. We use data from a hashtag activism campaign, #ILookLikeAnEngineer, launched to showcase diversity within engineering workforce, to examine how different elements of a campaign blend together. We specifically identify three distinct but interconnected ways in which social media supports activism: 1) modality — it allows users to participate through text, photos, and links; 2) messaging — it allows users to post and support multiple though related topics; and 3) actors — it provides a voice to different participants (individuals/organizations, men/women). Our analysis supports the idea that multivocality — the core idea that people leverage multiple ways of participating — is the key to campaign success. Our analysis of 19,492 original tweets and 89,650 retweets shows that multivocality allowed the campaign to receive support not just from individuals but from large corporations, media, and NGOs, who were able to share their perspective using their preferred modality giving rise to a new form of digital polyphonic narrative that supports their agenda.
Negotiating digital spaces in everyday life: A case study of Indian women and their digital use
Authors: Paul Anindita , Thompson Kim M.
Published: November 2018

New developments in digital technology and better and affordable access allow women unprecedented access to information and communication networks — if they are able to use digital technologies to access networks and digital information. This study presents a case study of motivations of women to use information and communication technologies (ICT) in a ubiquitous information environment. This study follows an interpretive paradigm to explore an understanding of culture and gender in a middle-class Indian context. Women in this report varied in terms of heavy/light and mandatory/voluntary use. We discuss the implications of such variations in terms of technology adoption for digital inclusion. Social factors, such as the role of parents and social communities, were found to influence women to develop and maintain interests in ICT that were reflected in their professional and personal lives. Some women were slow to adapt to ICT use as they tended to adhere to normative expectations which hindered ICT use. Women tend to have greater ICT use if it is for fulfilling familial roles and for communication.
Condição nutricional e sugestão de padrão alimentar para Chelonoidis sp
Authors: De Castro Isabella Rigo Werneck , Pinke Testa Carolyne Assis Eigenheer , Silva Diogo Cristo Silva e , Dos Santos Gisele Junqueira , Hippólito Alícia Giolo , Melchert Alessandra
Published: November 2018

Objetivou-se com esse trabalho realizar a avaliação nutricional e a sugestão de um padrão alimentar para o gênero Chelonoidis sp., usando dados biométricos como o peso, o escore de condição corporal e o comprimento e a largura do casco e do plastrão. Foram utilizados 52 híbridos, de jabuti-piranga (Chelonoidis carbonaria) e jabuti-tinga (Chelnoidis denticulata), com 27 indivíduos do sexo masculino e os outros 25 do feminino. A dieta fornecida foi uma combinação de fontes de proteína, leguminosas, verduras e frutas disponíveis no local para observação do consumo e comportamento alimentar individual. Com base nisso, eles foram classificados de acordo com o aspecto casco, preferência alimentar e escore de condição corporal, o que refletiu no efeito de dominância e frequência alimentar por meio da observação dos jabutis em 12 momentos. Para a análise estatística dos dados foram utilizados os procedimentos de análise de variância (ANOVA) one way e posteriormente aplicado o teste de Tukey, sendo considerado o nível de significância quando P<0,05. A frequência de alimentação dos animais foi determinada como um padrão para distinguir animais obesos de desnutridos.
Sucedâneo de fase inicial e crescimento para Tamanduá-bandeira (Myrmecophaga tridactyla)
Authors: Ribeiro Karen Ramos , Braz Jordana Gomide , Vieira Ananda Santos , Santos Ana Paula Rosa , Bianchini Mateus Assis , Morgado Thais Oliveira
Published: November 2018

Os tamanduás bandeira (Myrmecophaga tridactyla) são animais com ampla distribuição no território brasileiro. Com a redução de seu habitat natural pela expansão humana, esses animais se tornaram vítimas de grande número de acidentes em estradas e zonas urbanas, transformando a entrega de filhotes órfãos uma ocorrência comum no Hospital Veterinário da UFMT. Este trabalho tem por finalidade apresentar os resultados obtidos quanto ao manejo de tais filhotes, cujas mães vieram a óbito devido a causas externas. A alimentação artificial foi desenvolvida com ingredientes especiais, pensando em atender necessidades nutricionais nas duas etapas preliminares da vida a partir de duas dietas. A primeira a base de leite de cabra em pó integral, sucedâneo comercial para felinos domésticos, ovo cozido sem casca e fibra comercial em pó. E a segunda composta por leite zero lactose, sucedâneo comercial para desmame de felinos domésticos, ovo cozido sem casca e frutas. Apresentando resultados promissores quanto ao desenvolvimento ponderal dos filhotes.
Consumo voluntário e ingestão de nutrientes em Agapornis sp alimentados com ração comercial e sementes
Authors: Oliveira Julia Caroline , Fernandes Barbara , Moreno Tatiane , Rocha Chayane
Published: November 2018

Os psitacídeos em vida livre têm disponível grande variedade de alimentos na natureza, as suas escolhas alimentares baseiam-se na sabedoria nutricional obtida por meio de experiências ao passar das gerações, os tornando seletivos com sua alimentação, porém a alimentação de vida livre raramente é reproduzida em cativeiro. O objetivo deste trabalho foi analisar a ingestão voluntária e estimar a ingestão de nutrientes de dietas contendo ração e/ou sementes para Agapornis sp. Para tanto, 21 aves foram distribuídas em delineamento inteiramente casualizado em três tratamentos com sete repetições cada. Os tratamentos consistiram em: T1- ração extrusada (RE) + sementes de girassol (G), alpiste (A) e painço (P); T2- RE + A +P; T3- RE. O estudo teve duração de onze dias, sendo quatro de adaptação e sete de coleta de dados. Diariamente, foi disponibilizado para as aves 25% do peso corporal de cada item alimentar e, quantificado as sobras do comedouro e desperdício de alimentos. Para estimar a ingestão de nutrientes foram determinados em laboratório os teores matéria seca, de proteína bruta, extrato etéreo, cálcio e fósforo. Os dados de ingestão voluntária e ingestão de nutrientes foram submetidos à ANOVA e suas médias comparadas pelo Teste de Tukey (5%). Verificou-se que as aves que receberam todos os itens alimentares (T1) ingeriram maior quantidade total de MS (p<0,001) em relação ao T3. A ingestão de PB e EE foram maiores no T1 quando comparado aos T2 e T3. O consumo mínimo recomendado de Ca foi suprido somente nas aves que receberam apenas ração (T3) e diferiu dos T1 e T2. A ingestão de energia nas aves do T1 foi superior (p<0,0001) em relação ao T2 e T3. Conclui-se que as aves preferiram a ingestão de sementes em relação a ração e tal comportamento refletiu na maior ingestão de matéria seca e, a exigência mínima de cálcio só foi suprida para as aves que tiveram acesso exclusivo a ração
AVALIAÇÃO REPRODUTIVA DE PERIQUITOS AUSTRALIANOS PADRÃO INGLÊS (Melopsittacus undulatus) EM CATIVEIRO COM O USO DE MANEJO NUTRICIONAL
Authors: Couto Erica Pereira , Peixoto Junior Kleber Da Cunha
Published: November 2018

As necessidades nutricionais variam conforme a fase da vida, sendo que na fase reprodutiva se faz necessário o aumento da proteína bruta na dieta. Desta forma, o objetivo deste trabalho foi avaliar o efeito da suplementação com proteína na forma de albumina ou na forma de aminoácidos sobre a reprodução dos periquitos australianos padrão inglês (Melopsittacus undulatus). Para isto foram utilizados 21 gaiolas contendo um casal cada divididos em 3 grupos, sendo o Grupo 1 suplementado na água diariamente com produto comercial a base de aminoácidos (Aminosol®), o Grupo 2 o controle e o Grupo 3 o que recebeu acréscimo de albumina na forma de clara de ovo em pó misturado à farinhada obtendo-se um produto com 40,78% de proteína bruta (PB). Os dados foram submetidos à análise de variância (PROC GLM) (SAS Institute Inc., 2001) onde se verificou o efeito dos tratamentos sobre o total de ovos, total de ovos fertilizados e total de ovos não fertilizados, em seguida, utilizado o teste de comparação de médias ajustadas LSMEANS. Foi adotado o nível de significância de 5% para todas as análises realizadas. A quantidade total de ovos (p = 0,0829), ovos fertilizados (p = 0,2132) e ovos não fertilizados (p = 0,1443), não diferiram entre os tratamentos. Assim, concluiu-se que nas condições de criação avaliada, a suplementação de periquitos australianos padrão inglês com aminoácidos na água ou albumina na farinhada não altera a eficiência reprodutiva dos animais.
Consumo voluntário e ingestão de nutrientes em Forpus coelestis (tuim) alimentados com ração comercial e sementes.
Authors: Machado Rodrigo Girata , Fernandes Barbara , Oliveira Julia , Moreno Tatiane , Da Rocha Chayane
Published: November 2018

Avaliou-se consumo voluntário e estimou-se ingestão de nutrientes por Forpus coelestis frente à oferta de diferentes alimentos. Foram distribuídas 21 aves em três tratamentos e sete repetições, T1: Ração extrusada (RE), girassol (G), alpiste (A) e painço (P); T2: RE+A+P; T3: RE. Para cada alimento foram determinados teor de matéria seca (MS), proteína bruta (PB), extrato etéreo (EE), matéria mineral (MM), cálcio (Ca), fósforo (P) e energia bruta (EB). Foi estimada a ingestão total (IT) MS, nutrientes (g/dia) e EB (kcal/dia/kg). Não foi verificada diferença (p>0,05) para ITMS entre T1, T2 e T3 (4,180; 3,670 e 3,750g MS/ave/dia, respectivamente). Houve diferença para ITPB (p=0,015) e ITEB (p<0,0001) onde T1 apresentou maior ITPB (0,64g PB/MS/dia) e ITEB (25,18kcal/kg/dia) comparado a T2 e T3 (047; 0,50g PB/MS/dia e 15,58; 16,47kcal/kg/dia). A ITEE diferiu entre os tratamentos (p<0,0001) onde T1>T3>T2 (0,87; 0,39; 0,11g EE/MS/dia). Para ITCa e ITP houve diferença significativa entre os tratamentos (p<0,0001) sendo T3 (0,037g Ca/MS/dia)>T1 e T2 (0,007; 0,008g Ca/MS/dia) e T2 (0,100g P/MS/dia)>T1 e T3 (0,018 e 0,017g P/MS/dia). Entre T1 o alimento mais ingerido foi G>A>P>RE (p<0,0001: 2,40; 1,14; 0,58 e 0,06 g/ave/dia). Já entre T2 foi A>P>RE (2,23; 1,06; 0,38 g/ave/dia). A presença de alimento palatável fez com que o principal limitador de ingestão fosse o enchimento do trato digestório, demonstrando que, possivelmente, essas aves sejam incapazes de balancear sua dieta.