scholarly journals Best in 5 Minutes: Improving Students' Conceptual Understanding of Arch Construction and Behavior Using Physical Models of Masonry Arches in a Classroom Exercise

2020 ◽  
Author(s):  
Rachel Sangree ◽  
Benjamin Schafer
Keyword(s):  
Conceptual Understanding ◽  
Physical Models ◽  
Masonry Arches ◽  
Classroom Exercise ◽  
And Behavior ◽  
Arch Construction

scholarly journals Calibration of FARSITE fire area simulator in Iranian northern forests

2014 ◽  
Vol 2 (9) ◽  
pp. 6201-6240 ◽  
Author(s):  
R. Jahdi ◽  
M. Salis ◽  
A. A. Darvishsefat ◽  
F. J. Alcasena Urdiroz ◽  
V. Etemad ◽  
...  
Keyword(s):  
Vegetation Type ◽  
Fire Spread ◽  
Physical Models ◽  
Northern Iran ◽  
Burned Areas ◽  
Risk Monitoring ◽  
Spread Model ◽  
Fuel Models ◽  
And Behavior ◽  
In Fire

Abstract. Wildfire simulators based on empirical or physical models need to be locally calibrated and validated when used under conditions that differ from those where the simulators were originally developed. This study aims to calibrate FARSITE fire spread model considering a set of recent wildfires occurred in Northern Iran forests. Site specific fuel models in the study areas were selected by sampling the main natural vegetation type complexes and assigning standard fuel models. Overall, simulated fires presented reliable outputs that accurately replicated the observed fire perimeters and behavior. Standard fuel models of Scott and Burgan (2005) afforded better accuracy in the simulated fire perimeters than the standard fuel models of Anderson (1982). The best match between observed and modeled burned areas was observed on herbaceous type fuel models. Fire modeling showed a high potential for estimating spatial variability in fire spread and behavior in the study areas. This work represents a first step in the application of fire spread modeling on Northern Iran for wildfire risk monitoring and management.

Kinematic Stability of Masonry Arches

2010 ◽  
Vol 133-134 ◽  
pp. 429-434 ◽  
Author(s):  
Pierre Smars
Keyword(s):  
Limit Analysis ◽  
High Speed ◽  
Factor Of Safety ◽  
Probabilistic Approach ◽  
Physical Models ◽  
Geometrical Factor ◽  
Load Factor ◽  
Masonry Arches ◽  
Deformation Limit ◽  
Vertical Displacements

To quantify the safety of masonry arches and vaults using limit-analysis, various types of safety factors have been devised. The most well-known were introduced by Heyman: a “static factor of safety” (or load factor) assessing how vulnerable the structure is to increases in the living loads and a “geometrical factor of safety” assessing how critical the thickness of the structure is for its stability. In non seismic areas, one of the main risks of total or partial collapse of arches and vaults is excessive displacement of the supports (following walls or soil deformation). Limit analysis technique can be used to analyse this risk, quantifying movements permitted before collapse and evolution of the thrust on the supports. This analysis can be combined with pathological investigations and displacement monitoring to study the evolution of the risk and define a “kinematic factor of safety”. A software program was developed (a) to compute domains of stability for particular mechanisms of deformation, (b) to study possibility of transitions between mechanisms during deformation and (c) to interactively study the influence of movements of the supports on thrust and stability. Scaled physical models are used to validate the limit analysis approach, using an experimental rig where horizontal and vertical displacements are controlled by computer. A high-speed camera is used to study transition between mechanisms. Finally it is referred to techniques integrating this kinematic approach into a more general probabilistic approach, taking into account various uncertainties in the structure (shape, thickness, loads, movements).

scholarly journals Influence of the Cavitation Model on the Simulation of Cloud Cavitation on 2D Foil Section

2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
S. Frikha ◽  
O. Coutier-Delgosha ◽  
J. A. Astolfi
Keyword(s):  
Void Fraction ◽  
Analytical Study ◽  
Physical Models ◽  
Model Parameters ◽  
Source Terms ◽  
Cavitating Flows ◽  
Cavitation Model ◽  
Cloud Cavitation ◽  
Flow Configurations ◽  
And Behavior

For numerical simulations of cavitating flows, many physical models are currently used. One approach is the void fraction transport equation-based model including source terms for vaporization and condensation processes. Various source terms have been proposed by different researchers. However, they have been tested only in different flow configurations, which make direct comparisons between the results difficult. A comparative study, based on the expression of the source terms as a function of the pressure, is presented in the present paper. This analytical approach demonstrates a large resemblance between the models, and it also clarifies the influence of the model parameters on the vaporization and condensation terms and, therefore, on the cavity shape and behavior. Some of the models were also tested using a 2D CFD code in configurations of cavitation on two-dimensional foil sections. Void fraction distributions and frequency of the cavity oscillations were compared to existing experimental measurements. These numerical results confirm the analytical study.

scholarly journals The instructional situations in which mathematics teachers provide substantive feedback

2021 ◽  
Author(s):  
Roar B. Stovner ◽  
Kirsti Klette ◽  
Guri A. Nortvedt
Keyword(s):  
Conceptual Understanding ◽  
Mathematics Teachers ◽  
Mathematical Practices ◽  
Effective Feedback ◽  
Observation Instrument ◽  
Quality Feedback ◽  
Instructional Situation ◽  
Teachers And Students ◽  
And Behavior ◽  
Instructional Situations

AbstractFeedback provided by mathematics teachers usually addresses procedural skills and, to a much lesser extent, other competencies such as conceptual understanding or engagement in mathematical practices. As most previous literature has studied feedback provided on homework or video prompts, how teachers provide such feedback in the classroom is poorly understood. Here, sixteen lessons taught by five teachers were purposefully sampled from a larger video study (172 lessons) as lessons with high-quality feedback according to a standardized observation instrument. The analysis focused on the instructional situations in which teachers provided feedback. When teachers provided procedural feedback, the situations were orderly and effective. Feedback on conceptual understanding and mathematical practices was provided in situations when students were especially challenged, and entailed a series of complex decisions, thereby placing demands on the teachers to manage both the students’ understanding and behavior. We argue that researchers should focus on how teachers and students negotiate the instructional situation to allow for feedback on conceptual understanding or mathematical practices.

scholarly journals Calibration of FARSITE simulator in northern Iranian forests

2015 ◽  
Vol 15 (3) ◽  
pp. 443-459 ◽  
Author(s):  
R. Jahdi ◽  
M. Salis ◽  
A. A. Darvishsefat ◽  
M. A. Mostafavi ◽  
F. Alcasena ◽  
...  
Keyword(s):  
Vegetation Type ◽  
Fire Spread ◽  
Physical Models ◽  
Northern Iran ◽  
Burned Areas ◽  
Risk Monitoring ◽  
Spread Model ◽  
Fuel Models ◽  
And Behavior ◽  
In Fire

Abstract. Wildfire simulators based on empirical or physical models need to be locally calibrated and validated when used under conditions that differ from those where the simulators were originally developed. This study aims to calibrate the FARSITE fire spread model considering a set of recent wildfires that occurred in northern Iranian forests. Site-specific fuel models in the study areas were selected by sampling the main natural vegetation type complexes and assigning standard fuel models. Overall, simulated fires presented reliable outputs that accurately replicated the observed fire perimeters and behavior. Standard fuel models of Scott and Burgan (2005) afforded better accuracy in the simulated fire perimeters than the standard fuel models of Anderson (1982). The best match between observed and modeled burned areas was observed on herbaceous fuel models. Fire modeling showed a high potential for estimating spatial variability in fire spread and behavior in the study areas. This work represents a first step in the application of fire spread modeling in northern Iran for wildfire risk monitoring and management.

How Homo economicus lost her mind and how we can revive her

2018 ◽  
Vol 41 ◽  
Author(s):  
Peter DeScioli
Keyword(s):  
Economic Thought ◽  
History Of Economic Thought ◽  
Homo Economicus ◽  
Economic Theories ◽  
Target Article ◽  
History Of ◽  
The Mind ◽  
And Behavior

AbstractThe target article by Boyer & Petersen (B&P) contributes a vital message: that people have folk economic theories that shape their thoughts and behavior in the marketplace. This message is all the more important because, in the history of economic thought, Homo economicus was increasingly stripped of mental capacities. Intuitive theories can help restore the mind of Homo economicus.

The parent-offspring microbiome and neurobehavioral development

2019 ◽  
Vol 42 ◽  
Author(s):  
Jeffrey R. Alberts ◽  
Christopher Harshaw ◽  
Gregory E. Demas ◽  
Cara L. Wellman ◽  
Ardythe L. Morrow
Keyword(s):  
Mammalian Species ◽  
Social Emotional ◽  
Behavioral Measures ◽  
Neurobehavioral Development ◽  
Emotional Function ◽  
Neurobehavioral Outcomes ◽  
Methodological Approaches ◽  
And Behavior

Abstract We identify the significance and typical requirements of developmental analyses of the microbiome-gut-brain (MGB) in parents, offspring, and parent-offspring relations, which have particular importance for neurobehavioral outcomes in mammalian species, including humans. We call for a focus on behavioral measures of social-emotional function. Methodological approaches to interpreting relations between the microbiota and behavior are discussed.

Recent Radiative and Collisional Atomic Data of Astrophysical Interest

1988 ◽  
Vol 102 ◽  
pp. 129-132
Author(s):  
K.L. Baluja ◽  
K. Butler ◽  
J. Le Bourlot ◽  
C.J. Zeippen
Keyword(s):  
Mass Production ◽  
Bound States ◽  
Physical Models ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Atomic Data ◽  
Isoelectronic Sequence ◽  
Astrophysical Interest ◽  
Radiative Transitions ◽  
Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

TEM evaluation of graded SixGe1-x heterolayers

1991 ◽  
Vol 49 ◽  
pp. 894-895
Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gas Flow ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Dark Field ◽  
Bipolar Transistors ◽  
Structural Quality ◽  
Weak Beam ◽  
Transmission Electron ◽  
And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

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