Connecting the dots: Understanding the interrelated impacts of type,quality and children's awareness of design features and the mathematics content learning goals in digital math games and related learning outcomes

This study focused on an examination of how type, quality and children's awareness of design features in digital math games, along with an awareness of the mathematics goals of the game, were related to learning outcomes. We conducted a parallel conversion mixed methods study with 45 students in Grades 3 and 4 (ages 9–10). Students participated in clinical interviews using three digital math games. The results suggest a moderated mediation relationship in which the quality of the design features moderated the mediating impact of children's awareness of the game's design features, specifically when the child was aware of the mathematics content learning goal (MCLG) of the game. These findings show how important it is that design features are of high quality in a digital math game, and how this is intertwined with children's awareness of the features and the MCLG. When these variables intertwined in just the right way, the interactions between the children and the digital math game afforded mathematical learning growth.     

Removal of Cd(II), Hg(II), and Pb(II) ions from aqueous solution using p(HEMA/chitosan) membranes

An interpenetration network (IPN) was synthesized from 2‐hydroxyethyl methacrylate (HEMA) and chitosan, p(HEMA/chitosan) via UV‐initiated photo‐polymerization. The selectivity to different heavy metal ions viz Cd(II), Pb(II), and Hg(II) to the IPN membrane has been investigated from aqueous solution using bare pHEMA membrane as a control system. Removal efficiency of metal ions from aqueous solution using the IPN membranes increased with increasing chitosan content and initial metal ions concentrations, and the equilibrium time was reached within 60 min. Adsorption of all the tested heavy metal ions on the IPN membranes was found to be pH dependent and maximum adsorption was obtained at pH 5.0. The maximum adsorption capacities of the IPN membrane for Cd(II), Pb(II), and Hg(II) were 0.063, 0.179, and 0.197 mmol/g membrane, respectively. The adsorption of the Cd(II), Hg(II), and Pb(II) metal ions on the bare pHEMA membrane was not significant. When the heavy metal ions were in competition, the amounts of adsorbed metal ions were found to be 0.035 mmol/g for Cd(II), 0.074 mmol/g for Hg(II), and 0.153 mmol/g for Pb(II), the IPN membrane is significantly selective for Pb(II) ions. The stability constants of IPN membrane–metal ions complexes were calculated by the method of Ruzic. The results obtained from the kinetics and isotherm studies showed that the experimental data for the removal of heavy metal ions were well described with the second‐order kinetic equations and the Langmuir isotherm model. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Survey of multipath routing protocols for mobile ad hoc networks

This survey investigates multipath routing protocols for mobile ad hoc networks (MANETs). The main objectives of multipath routing protocols are to provide reliable communication and to ensure load balancing as well as to improve quality of service (QoS) of MANETs. These multipath protocols are broadly classified into five categories based on their major goals. The goals are to improve delay, provide reliability, reduce overhead, maximize network life and support hybrid routing. Multipath routing protocols address issues such as multiple paths discovery and maintaining these paths. Issues, objectives, performances, advantages and disadvantages of these protocols are investigated and summarized. A checklist is provided as a guideline so that a network designer can choose an appropriate multipath routing protocol to meet the network's application objectives.     

Reducing Dimensionality of Multi-regime Data for Failure Prognostics

Journal of Failure Analysis and Prevention - Over the last decade, the prognostics and health management literature has introduced many conceptual frameworks for remaining useful life predictions....     

Survey on communication architectures for wind energy integration with the smart grid

Communication systems are needed to integrate generated power from wind farms with the electrical grid. This paper provides a comprehensive review of available communication technologies, protocols and objectives related to wind energy and electrical grid integration. This paper summarizes the communication system solutions for wind generation. A major obstacle is an absence of unified communication architectures and standards.     

Evaluation of pre-treatment processes for HRS (hot rolled steel) in powder coating

Hot rolled steel (HRS) is used extensively in the automotive, agricultural and appliance industries. The corrosive response of HRS was investigated after it had been exposed to various surface treatments, prior to powder coating. The behaviour of three conversion coatings: zinc phosphate (ZnP), iron phosphate (FeP) and zirconium (Zr)-based nano-scaled, on HRS was studied. HRS is naturally covered with iron oxide scale and this was removed from the surface by mechanical and chemical processes, prior to the application of surface treatment and organic coatings. The following tests on differently treated panels were conducted to evaluate corrosion performance: adhesion tests such as, crosshatch, pull-off, and conical bending, SEM, XPS, salt spray and electro-chemical impedance studies were also performed. Good correlations were recorded showing that zinc phosphate conversion coating gave the best performance, and zirconium-based nano-structured conversion coating, was superior to that of iron phosphate conversion coatings on HRS.     

Effects of crushed clay brick aggregate on mortar durability

This paper reports an experimental study that aimed to investigate the effects of recycled clay brick, used as a part of fine aggregate, on mortar durability. The brick, in crushed form, was from a local brick manufacturer that salvages its off-standard products. It was used to replace 10% and 20% (by weight) of the river sand in mortar. Effects of the brick replacement on the mortar flow, compressive strength, shrinkage, freeze–thaw resistance, and alkali–silica reaction potential were investigated. The results showed that as the brick replacement level increased, the mortar flowability reduced. The 10% and 20% brick replacements had no negative effect on the mortar compressive strength and very limited effect on the mortar shrinkage. The freeze–thaw resistance of the mortar was improved by the brick replacement. However, the use of crushed brick as aggregate appeared not to reduce potential alkali–silica reaction. The microscopy study revealed the alkali–silica reaction product and associated cracking in the mortar. Additional study indicated that the brick aggregate used in the study had pessimum proportion, 30%, for the alkali–silica reaction expansion.     

Analytische Behandlung einer Kondensatoranordnung mit dielektrischen Platten

Übersicht Entwickelt wird ein analytisches Verfahren für die Bestimmung des Feldes dielektrischer Platten, die zwischen die leitenden Beläge eines Kondensators eingebracht werden. Da Gebiete verschiedener Dielektrizitätskonstanten zu einem Bereich zusammengefaßt werden, weisen die Eigenfunktionen nicht stetige Ableitungen auf und erfordern somit eine durch die Verschiedenheit der Dielektrizitätskonstanten gewichtete Norm. Die Erfüllung der Randbedingungen führt auf ein Gleichungssystem für die Konstanten der orthogonalen Feldkomponenten, deren Beitrag zur Energie in einfacher Weise durch das Produkt der genannten Konstanten mit den Störfunktionen des Gleichungssystems gegeben ist. Analytische Beziehungen für die Kraftwirkung werden ebenfalls angegeben und ausgewertet, wobei die durch die Randwirkungen hervorgerufene Kraftkomponente berechnet wird.

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Analytical treatment of a capacitor configuration with dielectric plates

Contents The field in the presence of dielectric plates placed between the conducting plates of a capacitor is determined using an analytical procedure. As regions of different dielectrical properties are combined to form a domain, the eigenfunctions have discontinuous differentials and require norms weighted with the different dielectric constants. The boundary conditions lead to a system of linear equations for the constants of the orthogonal field components, the contribution of which to the energy is found in a simple manner by forming products of the constants mentioned above with the load functions of the system under consideration. Analytic expressions for the forces are also given and evaluated where the components of the force due to the fringing effect are calculated.

     

Transienter Skineffekt in Kernen mit abschnittsweise verschiedenen Werkstoffeigenschaften

Übersicht Ein zylindrischer ober ebener Kern, der aus Materialien abschnittsweise verschiedener Permeabilität und Leitfähigkeit besteht, ist mit einer solenoidalen Wicklung umgeben, die von einem zeitlich beliebigen Strom durchflossen wird. Nach Erfüllung der Randbedingungen durch spezielle Orthogonalentwicklungen werden allgemeine Beziehungen für die Wirbelströme aufgestellt, die in den Kernteilen verschiedener Materialkonstanten induziert werden. Das gestellte Problem wird in allgemeiner Form für eine beliebige Unterteilung des Kerns gelöst und für den stationären Fall mit bekannten konventionellen Mitteln nachgeprüft. Für eine Drei- und Zwei-Medien-Anordnung werden detaillierte Beziehungen angegeben. In einem Beispiel wird der Gesamtstrom berechnet, der nach erfolgtem Einschaltvorgang in dem inneren Teil einer symmetrischen Drei-Medien-Anordnung induziert wird. Die Ergebnisse werden bei der zerstörungsfreien Materialprüfung angewandt.

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Transient skineffect in laminated cores with sectional different material properties

Contents A cylindrical or plane core consisting of regions with different conductivity and permeability is excited by a solenoidal current of arbitrary time dependence. Satisfying the boundary conditions by means of special orthogonal expansions, general formulae are set up for the eddy currents induced in the various different parts of the core. The problem mentioned above is solved in general manner for an arbitrary number of different sections and checked by known steady state solutions. Detail formulae are given for the three- and two-material systems. As a sample, the current being induced after a circuit closing operation in the inner part of a symmetrical three-core system is calculated. The results are useful to the methods of non-destructive testing of materials.

     

Phenolic composition,enzyme inhibitory,and antioxidant activity of <Emphasis Type="Italic">Bituminaria bituminosa</Emphasis>

This study aimed to evaluate the in vitro antioxidant and enzyme inhibitory activities of ethyl acetate, methanol, and water extracts of Bituminaria bituminosa. In phosphomolybdenum assay, the methanol extract showed the highest activity (166.78 μmol TEs/g dry plant). The water extract exhibited the highest scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH^?) and 2,2-azino-bis (3-ethylbenzothiazloine-6-sulphonic acid) (ABTS^?+). In addition, it exhibited the highest activity in cupric ion reducing (CUPRAC) and ferric reducing antioxidant power (FRAP) assays (41.26 and 46.82 μmol TEs/g dry plant). The extracts did not show cholinesterase and tyrosinase inhibitory activity. However, α-glucosidase inhibition assay resulted in the superiority of water extract (1233.86 μmol ACEs/g dry plant). In the case of α-amylase inhibitory assay, the ethyl acetate extract showed the highest activity (53.65 μmol ACEs/g dry plant). The water extract exhibited the highest phenolic content (31.70 μmol GAEs/g dry plant). In contrast, the methanol extract was found rich in flavonoid compounds (5.29 μmol REs/g dry plant). The water extract contained considerable amounts of rosmarinic acid, luteolin, quercetin, and rutin. Therefore, it can be used as a source of new and alternative antioxidant and enzyme inhibitory agents.