bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neural responses to various rewards and feedback in the brains of adolescent Internet addicts detected by functional magnetic resonance imaging
Authors: Kim Ji‐Eun , Son Jung‐Woo , Choi Won‐Hee , Kim Yeoung‐Rang , Oh Jong‐Hyun , Lee Seungbok , Kim Jang‐Kyu 
Published: February 2014

AimThis study aimed to examine differences in brain activation for various types of reward and feedback in adolescent Internet addicts (AIA) and normal adolescents (NA) using functional magnetic resonance imaging (fMRI).MethodsAIA (n = 15) and NA (n = 15) underwent fMRI while performing easy tasks for which performance feedback (PF), social reward (SR) (such as compliments), or monetary reward (MR) was given. Using the no reward (NR) condition, three types of contrasts (PF–NR, SR–NR, and MR–NR) were analyzed.ResultsIn NA, we observed activation in the reward‐related subcortical system, self‐related brain region, and other brain areas for the three contrasts, but these brain areas showed almost no activation in AIA. Instead, AIA showed significant activation in the dorsolateral prefrontal cortex for the PF–NR contrast and the negative correlation was found between the level of activation in the left superior temporal gyrus (BA 22) and the duration of Internet game use per day in AIA.ConclusionThese findings suggest that AIA show reduced levels of self‐related brain activation and decreased reward sensitivity irrespective of the type of reward and feedback. AIA may be only sensitive to error monitoring regardless of positive feelings, such as sense of satisfaction or achievement.
Internal and external regulation of plant organ stoichiometry
Authors: Minden V. , Kleyer M. 
Published: February 2014

AbstractInternal differences between plant organs are caused by the functional differentiation of plant tissue, whereas external supply rates of elements constrain nutrient uptake. Previous studies have concentrated on foliar or whole‐plant stoichiometric response to the environment, whereas investigation of organ‐specific comparisons is still pending. We explore C:N:P ratios of stems, leaves, diaspores and belowground organs in marsh plants, and evaluate the influence of environmental constraints using standardised major axis regression (SMA). For a pooled dataset, SMA resulted in distinct patterns of isometric and anisometric slopes between plant organs. Bivariate line‐fitting for a split dataset of four ecological groups revealed that species of the frequently inundated marsh had higher N:C ratios than those of the infrequently inundated marsh. The influence of nutrient availability was detectable in decreased P:C and increased N:P ratios in P‐poor sites. Across ecological groups, leaves and diaspores showed higher elemental homeostasis than stems and belowground organs. Any change in N:C ratios of belowground organs and diaspores in response to the environment was accompanied by an even stronger internal change in stem N:C ratios, indicating a pivotal role of stems of herbaceous plants in ecosystem processes. We found distinct patterns of C:N:P ratios in plant organs related to their internal function and external environmental constraints. Leaves and diaspores showed a higher degree of homeostasis than stems and belowground organs. We detected a clear external signal in element:element ratios of plant organs, with low soil P translating into lower tissue P:C ratio and stronger N retention in leaves as a response to salt stress.
Dialysis Dosing for Chronic Hemodialysis: Beyond Kt/V
Authors: Daugirdas John T. 
Published: February 2014

AbstractCurrent views regarding hemodialysis adequacy reach beyond indices of small solute removal such as Kt/V. Nevertheless, new Kt/V‐based constructs such as the standard Kt/V, which adjusts not only for dialysis frequency, but which also represents removal of sequestered solutes rather than easily removed urea, continue to be useful. The scaling of dialysis dose to measures of size other than body water results in higher recommended doses of dialysis for children, small patients, and women, compared with the current body water‐based scaling approach. Aside from small solute removal, increasing weekly time on dialysis results in slower removal of fluid with better tolerance and with increased removal of phosphorus, although both salt and water and phosphorus control often respond to efforts to reduce intake. The intermediate term benefits of removing larger middle molecules such as beta‐2‐microglobulin appear to be modest, and the benefits of removal of protein‐bound uremic toxins remain to be proved in controlled trials.
Square Heating Applied to Shearography and Active Infrared Thermography Measurements Coupling: From Feasibility Test in Laboratory to Numerical Study of Pultruded CFRP Plates Glued on Concrete Specimen
Authors: Théroux L.‐D. , Dumoulin J. , Maladague X. 
Published: February 2014

ABSTRACTThis paper investigates thermography and shearography couplings, using feasibility trials and numerical simulations, for non‐destructive control evaluations of bonding of carbon fiber‐reinforced polymer plates glued over concrete structures. Those are well‐known methods in non‐destructive testing (NDT) applied to civil engineering, but in this context, they are seen as paired because they use the same excitation source: square‐pulsed optical heating. Furthermore, because both methods are based on different properties, the detection of defects is optimised regardless of its nature or type. The combination of the methods allows the measurement of a thermal as well as a thermomechanical response from the structure at the same time. A quick review of those methods and their respective advantage and inconvenient is mentioned. An in‐depth study of the interpretation of the thermal and mechanical responses is carried out in relation to the thermal excitation. Then, the thought process behind the conception of the finite element model and its limitation is discussed. The experimental setup, used for feasibility testing, is described as well as a thorough analysis of the experimental and simulated results. Finally, the pairing of both methods is discussed regarding the evaluation of the bond quality, as well as the similitude of the sample and its numerical model.
Rice germline‐specific Argonaute MEL1 protein binds to phasiRNAs generated from more than 700 lincRNAs
Authors: Komiya Reina , Ohyanagi Hajime , Niihama Mitsuru , Watanabe Toshiaki , Nakano Mutsuko , Kurata Nori , Nonomura Ken‐Ichi 
Published: February 2014

SummarySmall RNAs that interact with Argonaute (AGO) proteins play central roles in RNA‐mediated silencing. MEIOSIS ARRESTED AT LEPTOTENE1 (MEL1), a rice AGO, has specific functions in the development of pre‐meiotic germ cells and the progression of meiosis. Here, we show that MEL1, which is located mostly in the cytoplasm of germ cells, associates preferentially with 21‐nucleotide phased small interfering RNAs (phasiRNAs) that bear a 5′‐terminal cytosine. Most phasiRNAs are derived from 1171 intergenic clusters distributed on all rice chromosomes. From these clusters, over 700 large intergenic, non‐coding RNAs (lincRNAs) that contain the consensus sequence complementary to miR2118 are transcribed specifically in inflorescences, and cleaved within the miR2118 site. Cleaved lincRNAs are processed via DICER‐LIKE4 (DCL4) protein, resulting in production of phasiRNAs. This study provides the evidence that the miR2118‐dependent and the DCL4‐dependent pathways are both required for biogenesis of 21‐nt phasiRNAs associated with germline‐specific MEL1 AGO in rice, and over 700 lincRNAs are key factors for induction of this biogenesis during reproductive‐specific stages.
Artificial Cochlear Hair Cells Using Active Piezoelectric Materials
Authors: Joyce Bryan S. , Tarazaga Pablo A. 
Published: February 2014

The inner hair cells (IHC’s) and outer hair cells (OHC’s) in the cochlea are vital components in the process of hearing. The IHC’s are responsible for converting sound-induced vibration into electrical signals. The OHC’s produce forces that amplify these vibrations and therefore enhance the electrical signals produced by the IHC’s. The resulting “cochlear amplifier” produces a nonlinear amplification which gives the ear its ability to detect sound pressure levels ranging from 20 μPa to 20 Pa (0 to 120 dB).
This paper presents the modeling and testing of an artificial hair cell (AHC) piezoelectric sensor inspired by the hair cells found in the mammalian ear. The sensor is a bimorph cantilever beam consisting of a sensing piezoceramic element and an actuating piezoceramic element bonded to a brass substrate. The sensing element is used to detect the mechanical motion of the beam. Output feedback control can be used to send a voltage signal to the actuating element and alter the frequency response of the beam. A control law, which modifies the linear damping term of the first mode and introduces cubic damping, is used to create a closed-loop system perched at a Hopf bifurcation. The result is a system that produces a nonlinear amplification of the beam’s mechanical response in a manner which mimics the nonlinear behavior of the mammalian cochlea. This active sensor is studied under base acceleration and the initial test results are compared to a finite element model. Simulations of the closed-loop system are examined for the system with a single mode and for the system with multiple modes.
Phased Array Beamsteering in Composite Laminates for Guided Wave Structural Health Monitoring
Authors: Osterc Peter , Kim Daewon , Yoo Byungseok 
Published: February 2014

In this study, a guided wave phased array beamsteering approach is applied to composite laminates. Current beamsteering algorithms derived for isotropic materials assume omnidirectional wave propagation. Due to inherent anisotropy in composites, guided wave propagation varies with direction and wavefronts no longer have perfect circular shapes.
By examining slowness, velocity and wave curves for a given composite laminate, the wavefront from a single source can be described as a function of the angle of propagation and distance from origin. Using this approach, a generic delay and sum beamforming algorithm for composite laminates is developed for any desired wave mode.
It is shown that anisotropic wave mode regions can be effectively used for beamsteering in certain directions with a linear array and performance similar or even better than isotropic case. However, the useful range of angles with a 1d linear array for anisotropic wave modes is quite small and other directions exhibit undesired grating lobes and large sidelobes.
A Memory Variable Approach to Modeling the Magneto-Mechanical Behavior of Magnetic Shape Memory Alloys
Authors: LaMaster Doug , Feigenbaum Heidi , Nelson Isaac , Ciocanel Constantin 
Published: February 2014

Magnetic shape memory alloys (MSMAs) have attracted interest because of their considerable recoverable strain (up to 10%) and fast response time (1 kilohertz or higher). MSMAs are comprised of martensitic variants that have tetragonal unit cells and a magnetization vector that is innately aligned with the short side of the unit cell. These variants rotate either to align the magnetization vector with an applied magnetic field or to align the short side of the unit cell with an applied compressive stress. This reorientation leads to a mechanical strain and an overall change in the material’s magnetization, allowing MSMAs to be used as actuators, sensors, and power harvesters.
This paper builds upon the work of Kiefer and Lagoudas [4,5] as well as improvements proposed by LaMaster et al. [1] to present a thermodynamic based model to predict the response of an MSMA to axial mechanical loading and transverse magnetic loading. This work is unique, however, in its use of a memory variable, which references the last stable configuration. This is similar to the approach used by Saint-Sulpice [2] in modeling SMA wires. The resulting model has zero driving force for reorientation of variants at the beginning of any load and again when the load is removed. Thus the model predicts what is seen physically, that the material is stable when no magneto-mechanical load is present. Furthermore, this model is more physical and less empirical than others in the literature, having only 2 material parameters associated with the stress-strain or stress-field response. In addition, this model includes evolution rules for the magnetic domain volume fractions and the angle of rotation of the magnetization vectors based on thermodynamic requirements.
The resulting model is calibrated and predictions are compared with both the more established Keifer and Lagoudas model as well as experimental data. Results show decent correlation with experiments. The model can be further improved by calibrating the demagnetization factor to experimentally measured changes in magnetic field.
Towards Frequency-Independent Vibration-Based Energy Harvesting Using Frequency Up-Conversion and Power Analysis
Authors: Patel Ambrish P. , Wickenheiser Adam M. 
Published: February 2014

Traditionally, vibration-based energy harvesters have been designed for specific base excitation frequencies by matching their natural frequencies. However, harvesting energy from common human motions is challenging because the low frequencies involved are incompatible with small, light-weight transducers, which have much higher natural frequencies. By using the frequency up-conversion method, a vibration-based, nonlinear, magnetically excited energy harvester exhibits efficient, broadband, frequency-independent performance.
A complete model is provided for an energy harvester utilizing the frequency up-conversion method that defines the relationship between the enclosure excitation, the base excitation and the stationary magnets, where the base of the beam is mounted elastically inside an enclosure. The average power output of a vibration-based energy harvester with frequency up-conversion is analyzed using artificial and naturally occurring base excitations such as sinusoidal and walking motions, respectively. Simulations are provided to demonstrate the broadband capabilities of vibration-based energy harvesters with frequency up-conversion, especially for driving frequencies lower than the fundamental frequency, where significant increase in power output are observed when utilizing frequency up-conversion. In addition, the advantages and limitations of approximating a range of natural base excitations with a set of orthogonal basis functions are explored, which provides motivation for Wavelets Analysis. Finally, a procedure is proposed to determine the maximum expected power output.
Modeling and Control of Lozenge-Shaped Dielectric Elastomer Generators
Authors: Moretti Giacomo , Fontana Marco , Vertechy Rocco 
Published: February 2014

Dielectric Elastomers (DEs) are a very promising technology for the development of energy harvesting devices based on the variable-capacitance electrostatic generator principle. As compared to other technologies, DE Generators (DEGs) are solid-state energy conversion systems which potentially feature: 1) large energy densities, 2) good energy conversion efficiency that is rather independent of cycle frequency, 3) easiness of manufacturing and assembling, 4) high shock resistance, 5) silent operation, 6) low cost. Envisioned applications for DEGs are in devices that convert ocean wave energy into usable electricity.
This paper introduces the Lozenge-Shaped DEG (LS-DEG) that is a specific type of planar DE transducer with one degree of freedom. A LS-DEG consists of a planar DE membrane that is connected along its perimeter to the links of a parallelogram four-bar mechanism. As the mechanism is put into reciprocal motion, the DE membrane varies its capacitance that is then employed as a charge pump to convert external mechanical work into usable electricity.
Specifically, this paper describes the functioning principle of LS-DEGs, and provides a comparison between different hyper-elastic models that can be used to predict the energy harvesting performances of realistic prototypes. Case studies are presented which address the constrained optimization of LS-DEGs subjected to failure criteria and practical design constraints.
An Origami-Inspired Self-Deployable Array
Authors: Zirbel Shannon A. , Wilson Mary E. , Magleby Spencer P. , Howell Larry L. 
Published: February 2014

The objective of this paper is to show the development of a compact, self-deploying array based on the tapered map fold. The tapered map fold was modified by applying an elastic membrane to one side of the array and adequately spacing the panels adjacent to valley folds. Through this approach, the array can be folded into a fully dense volume when stowed. The panels are dimensioned to account for the panel thickness when folded, which otherwise would prevent the model from reaching a fully dense form.
The folding motion is achieved by creating a rigid-foldable model of the origami-inspired crease pattern. The paper discusses a variety of approaches for creating rigid origami from the map fold, including pleat hinges and spacer panels. The tapered map fold is rigid-foldable through the incorporation of tapered spacer panels. By choosing appropriate values for the angles and tapered spacer panel dimensions, the tapered map fold is fully dense when stowed. The tapered spacer panels also enable the model to have a single degree of freedom of actuation. Stored strain energy in the elastic membrane enables self-actuation of the model. Applying a membrane also simplifies fabrication of the array.
Potential applications for the array include a collapsible solar array, or other military or backpacking applications.
Shrouding the First Blade of High Temperature Turbines
Authors: Mamaev B. I. , Petukhovsky M. M. , Pozdnyakov A. V. 
Published: February 2014

Blade shrouding gives an opportunity to increase the HPT (high pressure turbine) first stage efficiency by 2–3 %. However, if high gas temperature and high circumferential velocity are at the stage, shrouding can be problematic due to load increasing at blade/disk attachment and high temperature of the shroud itself.
To make blade/disk attachment more reliable the shroud axial width has to be decreased by increasing a relative pitch of airfoil cascades t (t = t / b, where t – pitch, b – chord) at the blade tip span. According to experience for a flow with β1 = 50 – 85°, M2 = 0.8 – 1, and Re = (0.8 – 1)•106 high efficient cascades with t = 0.93 – 1.05 can be designed. Application of such a profiling for GTE (gas turbine engine) turbine is demonstrated here. In the turbine meridian flow path the blade was drastically tapered to the tip (tip width was 53 % of the mean width and 46 % of the hub width).
To lighten the blade a partial shrouding can be also applied. Model turbine tests showed that local cuts at the front shroud area and the aft shroud area at the airfoil pressure side influenced the efficiency weakly.
Required shroud temperature is provided with a cooling. The aircraft turbine with a governed cooling system and a radial clearance control is an example here.
In this case the shroud had 3 labyrinth ribs. The shrouding decreased radial clearance by 0.8 mm at main design modes that increased efficiency by ∼ 1.5 %.
To cool down the shroud the air downstream the compressor was fed into the cavity behind the front labyrinth rib. At maximal mode with full cooling the relative coolant mass flow (to the compressor mass flow) was mc = 1.3 % and gas leakages through the labyrinth were 0.2 %. It gave acceptable mixed temperature of 530°C in the cavity over the shroud. At cruise high altitude mode and a lower gas temperature and partial cooling with mc = 0.4 % and gas leakages of 0.1 % the mixed temperature also did not exceed 530°C over the shroud.
The assessment with taking into account changes of the clearance, the coolant mass flow, and gas leakages showed that the shrouding provided the engine economy improvement by 0.7 – 0.9 % for both modes.
For GTPU (gas turbine power unit) the first blade shrouding can be more complicated. However, even the slight turbine efficiency increase provides considerable profits due to GTPU huge power output and long term running.
So, when GTE and GTPU designing starts, it is reasonable to consider the turbine first blade shrouding. Here the integral evaluation criterion, which includes the assessment of a possible income from the unit full life cycle running, has to be applied.
Turbine Split Rings Thermal Design Using Conjugate Numerical Simulation
Authors: Tikhonov Aleksei S. , Shvyrev Andrey A. , Samokhvalov Nikolay Yu. 
Published: February 2014

One of the key factors ensuring gas turbine engines (GTE) competitiveness is improvement of life, reliability and fuel efficiency. However fuel efficiency improvement and the required increase of turbine inlet gas temperature (T*g) can result in gas turbine engine life reduction because of hot path components structural properties deterioration.
Considering circumferential nonuniformity, local gas temperature T*g can reach 2500 K. Under these conditions the largest attention at designing is paid to reliable cooling of turbine vanes and blades. At present in design practice and scientific publications comparatively little attention is paid to detailed study of turbine split rings thermal condition. At the same time the experience of modern GTE operation shows high possibility of defects occurrence in turbine 1st stage split ring.
This work objective is to perform conjugate numerical simulation (gas dynamics + heat transfer) of thermal condition for the turbine 1st stage split ring in a modern GTE.
This research main task is to determine the split ring thermal condition by defining the conjugate gas dynamics and heat transfer result in ANSYS CFX 13.0 package. The research subject is the turbine 1st stage split ring. The split ring was simulated together with the cavity of cooling air supply from vanes through the case. Besides turbine 1st stage vanes and blades have been simulated. Patterns of total temperature (T*Max = 2000 °C) and pressure and turbulence level at vanes inlet (19.2 %) have been defined based on results of calculating the 1st stage vanes together with the combustor.
The obtained results of numerical simulation are well coherent with various experimental studies (measurements of static pressure and temperature in supply cavity, metallography).
Based on the obtained performance of the split ring cooling system and its thermal condition, the split ring design has been considerably modified (one supply cavity has been split into separate cavities, the number and arrangement of perforation holes have been changed etc.). All these made it possible to reduce considerably (by 40…50 °C) the split ring temperature comparing with the initial design.
The design practice has been added with the methods which make it possible to define thermal condition of GTE turbine components by conjugating gas dynamics and heat transfer problems and this fact will allow to improve the designing level substantially and to consider the influence of different factors on aerodynamics and thermal state of turbine components in an integrated programming and computing suite.