The role of multiple representations in the understanding of ideal gas problems

2011 ◽  
Vol 12 (3) ◽  
pp. 283-293 ◽  
Author(s):  
Seán P. Madden ◽  
Loretta L. Jones ◽  
Jrène Rahm
Keyword(s):  
Multiple Representations ◽  
Ideal Gas

scholarly journals Induction of Changes in Internal Gas Pressure of Bulky Plant Organs by Temperature Gradients

1990 ◽  
Vol 115 (2) ◽  
pp. 308-312 ◽  
Author(s):  
Kenneth A. Corey ◽  
Zhi-Yi Tan
Keyword(s):  
Bath Temperature ◽  
Ideal Gas ◽  
Gas Pressure ◽  
Temperature Gradients ◽  
Maximum Pressure ◽  
Plant Organs ◽  
Ideal Gas Law ◽  
Increasing Temperature ◽  
Pressure Changes

Water manometers were connected to fruits of tomato (Lycopersicon esculentum Mill.) and pepper (Capsicum annuum L.), and then fruits were submerged in water baths providing initial temperature gradients between fruit and water of 0 to 19C. Apple (Malus domestics Borkh.) fruits, carrot (Daucus carota L.) roots, witloof chicory (Cichorium intybus L.) roots, rhubarb Rheum rhabarbarum L.) petioles, and pokeweed (Phytolacca americana L.) stems were subjected to water bath temperature gradients of 5C. Internal partial vacuums developed in all organs within minutes of imposing the gradients. The maximum partial vacuums in tomato and pepper fruits increased with increasing temperature gradients. Uptake of water accompanied changes in internal pressure reaching maxima of 17% (w/w) and 2% (w/w) of pepper and tomato fruits, respectively, after 22 hours. Maximum pressure changes achieved in bulky organs deviated from those predicted by the ideal gas law, possibly due to concomitant changes in gas pressure upon replacement of intercellular spaces with water and dissolution of CO2. Partial vacuums also developed in pepper fruits, rhubarb petioles, and pokeweed stems following exposure to air 15C cooler than initial organ temperatures. Results point to the role of temperature gradients in the transport of liquids and gases in plant organs.

The CHREST Architecture for a Functioning Mind

2011 ◽  
pp. 204-224 ◽  
Author(s):  
Fernand Gobet ◽  
Peter C.R. Logan
Keyword(s):  
Theory Of Mind ◽  
Empirical Data ◽  
Multiple Representations ◽  
Learning Cycle ◽  
Full Theory ◽  
Cognitive Limitations ◽  
Self Organisation ◽  
Main Components ◽  
Shed Light

This chapter provides an introduction to the CHREST architecture of cognition and shows how this architecture can help develop a full theory of mind. After describing the main components and mechanisms of the architecture, we discuss several domains where it has already been successfully applied, such as in the psychology of expert behaviour, the acquisition of language by children, and the learning of multiple representations in physics. We highlight the characteristics of CHREST that enable it to account for empirical data, including self-organisation, an emphasis on cognitive limitations, the presence of a perception-learning cycle, and the use of naturalistic data as input for learning. We argue that some of these characteristics can help shed light on the hard questions facing theorists developing a full theory of mind, such as intuition, the acquisition and use of concepts, the link between cognition and emotions, and the role of embodiment.

Supercooling in hypersonic nitrogen wind tunnels

1994 ◽  
Vol 269 ◽  
pp. 283-299 ◽  
Author(s):  
Wayland C. Griffith ◽  
William J. Yanta ◽  
William C. Ragsdale
Keyword(s):  
Vibrational Energy ◽  
Ideal Gas ◽  
Wind Tunnels ◽  
Pure Nitrogen ◽  
Real Gas ◽  
Absolute Limit ◽  
Real Gas Effects ◽  
Supercooled Region ◽  
The Ideal

Recent experimental observation of supercooling in large hypersonic wind tunnels using pure nitrogen identified a broad range of non-equilibrium metastable vapour states of the flow in the test cell. To investigate this phenomenon a number of real-gas effects are analysed and compared with predictions made using the ideal-gas equation of state and equilibrium thermodynamics. The observed limit on the extent of supercooling is found to be at 60% of the temperature difference from the sublimation line to Gibbs’ absolute limit on phase stability. The mass fraction then condensing is calculated to be 12–14%. Included in the study are virial effects, quantization of rotational and vibrational energy, and the possible role of vibrational relaxation and freezing in supercooling. Results suggest that use of the supercooled region to enlarge the Mach–Reynolds number test envelope may be practical. Data from model tests in supercooled flows support this possibility.

scholarly journals Quantum quench dynamics of the attractive one-dimensional Bose gas via the coordinate Bethe ansatz

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Jan Zill ◽  
Tod Wright ◽  
Karen Kheruntsyan ◽  
Thomas Gasenzer ◽  
Matthew Davis
Keyword(s):  
Bethe Ansatz ◽  
Correlation Functions ◽  
Bound States ◽  
Delta Function ◽  
Ideal Gas ◽  
Relaxation Dynamics ◽  
Temperature Correlation ◽  
One Dimensional ◽  
Quench Dynamics

We use the coordinate Bethe ansatz to study the Lieb–Liniger model of a one-dimensional gas of bosons on a finite-sized ring interacting via an attractive delta-function potential. We calculate zero-temperature correlation functions for seven particles in the vicinity of the crossover to a localized solitonic state and study the dynamics of a system of four particles quenched to attractive interactions from the ideal-gas ground state. We determine the time evolution of correlation functions, as well as their temporal averages, and discuss the role of bound states in shaping the postquench correlations and relaxation dynamics.

scholarly journals Meaning Making with Multiple Representations: a Case Study of a Preservice Teacher Creating a Digital Explanation

2022 ◽  
Author(s):  
Wendy Nielsen ◽  
Annette Turney ◽  
Helen Georgiou ◽  
Pauline Jones
Keyword(s):  
Preservice Teachers ◽  
Meaning Making ◽  
Multiple Representations ◽  
Construction Process ◽  
Video Capture ◽  
Assessment Task ◽  
Multimodal Analysis ◽  
Insight Into

AbstractThe construction of dynamic multimedia products requires the selection and integration of a range of semiotic resources. As an assessment task for preservice teachers, this construction process is complex but has significant potential for learning. To investigate how weaving together multiple representations in such tasks enables learners to develop conceptual understanding, the paper presents an indicative case study of a 2nd-year preservice primary (K-6) teacher who created a digital explanation on the topic of ‘transparency’ for stage 3 children (ages 11–12). We focus on data gathered during the 3-h construction process including artefacts such as images, online searches, websites accessed and paper records used for planning; the digital explanation as product; audio and video capture of the construction process and pre- and post-construction interviews. Using multimodal analysis, we examine these data to understand how meanings are negotiated as the maker moves iteratively among multiple representations and through semiotic choices within these representations to explain the science concept. The analyses illustrate the complexity of the construction process while providing insight into the creator’s decision-making and to her developing semiotic and conceptual understandings. These findings allow us to build on the concept of cumulative semiotic progression (Hoban & Nielsen, Research in Science Education, 35, 1101-1119, 2013) by explicating the role of iterative reasoning in the production of pedagogic multimedia.

scholarly journals The Master Key to the Problem of Reversible Chemical Hydrogen Storage is 12 kJ (mol H2)-1

2021 ◽  
Author(s):  
Roland Hermann Pawelke
Keyword(s):  
Hydrogen Storage ◽  
Storage Capacity ◽  
Ideal Gas ◽  
Equilibrium Thermodynamics ◽  
Ideal Gas Law ◽  
Chemical Hydrogen Storage ◽  
Co Doped ◽  
Normative Role ◽  
The Ideal

<p>This article shows up the intrinsic thermodynamic boundaries to reversible mass transfer on basis of the ideal gas law and classic equilibrium thermodynamics in relation to chemical hydrogen storage. In the event, a global picture of reversible chemical hydrogen storage is unveiled, including an explanation of partial reversibility. The findings of this work help to clarify problems of metal hydride chemistry which otherwise are difficult if not impossible to solve in convergent manner, e.g. why the substitution of 4 mol % Na by K in Ti-doped NaAlH<sub>4</sub> raises the reversible storage capacity by 42 % or the way the dopants take effect in (Rb/K)-co-doped Mg(NH<sub>2</sub>)<sub>2</sub>/2LiH. This work's result is of a wider significance since based on two cornerstones of physical chemistry and particularly for the normative role of hydrogen electrodes to electrochemistry.</p>

The linear mixture formula in non-equilibrium chemical kinetics

1977 ◽  
Vol 55 (5) ◽  
pp. 802-811 ◽  
Author(s):  
Robert K. Boyd
Keyword(s):  
Chemical Kinetics ◽  
Ideal Gas ◽  
Eigenvalue Approximation ◽  
Mixture Formula ◽  
Collision Partner ◽  
Recombination Reactions ◽  
Kinetics Of ◽  
Equilibrium Chemical ◽  
Non Equilibrium

The recent extensions of the 'eigenvalue approximation' of non-equilibrium kinetics proposed by Bartis and Widom to explain in a direct qualitative sense some general features of phenomenological chemical kinetics in ideal gas systems, have been used to investigate the problem of the 'linear mixture formula' applied to non-equilibrium kinetics of reactions proceeding in mixtures. For isomerization reactions in mixtures dilute in reactant, the model of Bartis and Widom, without further embellishment, has been shown to justify such an equation. Extrapolation of this result to account for recent empirical successes of a linear mixture formula in dissociation–recombination reactions of diatomic molecules X2 is not straightforward; the physical implications of the mathematical approximations employed are examined, and the non-linear recombination term is accounted for in the present purely qualitative context by an appropriate linearization. However, the appreciable contributions from X2–X2 collisions, under the conditions of the experiments cited, introduce inescapable non-linearities if vibration–vibration exchange, for example, is important. Problems associated with the role of the free atom X as a collision partner seem likely to be less important.

scholarly journals The Straightforward Route Towards the Theoretical Specific Free Enthalpy of Electrochemical Reactions

2021 ◽  
Author(s):  
Roland Hermann Pawelke
Keyword(s):  
Ideal Gas ◽  
Electrochemical Reactions ◽  
Free Enthalpy ◽  
Hydrogen Electrode ◽  
Battery Cell ◽  
Faraday’S Law ◽  
Ideal Gas Law ◽  
Sodium Sulfur

<p></p>This paper outlines a simple yet precise method for identifying the theoretical specific free enthalpy of electrochemical reactions on basis of the ideal gas law, equilibrium thermodynamics and Faraday's law, exploiting the normative role of the standard hydrogen electrode in electrochemistry. The result of this approach are discussed in relation to four battery cell reaction examples: LiCoO<sub>2</sub>/C<sub>6</sub>, LiFePO<sub>4</sub>/C<sub>6</sub>, sodium-sulfur (NAS) and NaCl–Ni (ZEBRA). The agreement between calculated and practical values is near-excellent for even stoichiometries which bespeaks the virtually ideal nature of reversible reactions and the quality of the practical optimization efforts alike. These findings highlight the principal nature of intrinsic thermodynamic limitation to equilibrium mass transfer and its key role towards understanding reversible chemical energy storage in a global sense.<br><p></p>

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