Search results for " laboratory experiment"
showing 10 items of 10 documents
Experimental observations of upstream overdeepening
2005
The issue of morphodynamic influence in meandering streams is investigated through a series of laboratory experiments on curved and straight flumes. Both qualitative and quantitative observations confirm the suitability of the recent theoretical developments (Zolezzi & Seminara 2001) that indicate the occurrence of two distinct regimes of morphodynamic influence, depending on the value of the width ratio of the channel β. The threshold value βR separating the upstream from the downstream influence regimes coincides with the resonant value discovered by Blondeaux & Seminara (1985). Indeed it is observed that upstream influence may occur only in relatively wide channels, while narrower stream…
The Consistency of Fairness Rules: An Experimental Study
2010
In the last two decades, experimental papers on distributive justice have abounded. Two main results have been replicated. Firstly, there is a multiplicity of fairness rules. Secondly, fairness decisions differ depending on the context. This paper studies individual consistency in the use of fairness rules, as well as the structural factors that lead people to be inconsistent. We use a within-subject design, which allows us to compare individual behavior when the context changes. In line with the literature, we find a multiplicity of fairness rules. However, when we control for consistency, the set of fairness rules is considerably smaller. Only selfishness and strict egalitarianism seem to…
Temptation and commitment in the laboratory
2010
Temptation and self-control in intertemporal choice environments are receiving increasing attention in the theoretical economics literature. Nevertheless, there remains a scarcity of empirical evidence from controlled environments informing behavior under repeated temptations. This is unfortunate in light of the fact that in many natural environments, the same temptation must be repeatedly resisted. This paper fills that gap by reporting data from a novel laboratory study of economic decisions under repeat temptations. Subjects are repeatedly offered an option with instantaneous benefit that also entails a substantial reduction to overall earnings. We show that this option is "tempting" in …
An Inquiry Based Approach to the study of energy exchange by thermal radiation
2012
A teaching-learning sequence regarding the investigation of energy exchange by thermal radiation, conduction and convection is under development within the context of “Establish”, a FP7 European Project aimed at promoting and developing Inquiry Based Science Education in European Secondary Schools. Here we present some relevant laboratory activities of this inquiry-oriented teaching/learning sequence for secondary school level students (or even first-level university ones), aimed at investigating the physics of energy transmission by thermal radiation. In traditional laboratory work, the focus of students activities is mostly dedicated on verifying information previously transferred by the …
Turbulence structure and coherent motion in a straight laboratory flume
2012
An inquiry-based approach to Maxwell distribution: a case study with engineering students
2013
The concept of distribution is a fundamental component of statistical thinking. This paper describes a teaching approach for it that uses a specific activity related to the field of statistical mechanics. The concept of the velocity distribution of a particle system is dealt with using an inquiry-based approach involving an experimental examination of Maxwell’s distribution. Some outcomes of a teaching experiment held at the Faculty of Engineering of the University of Palermo, Italy are described.
Measurement of the Convective Heat-Transfer Coefficient
2014
We propose an experiment for investigating how objects cool down toward the thermal equilibrium with its surrounding through convection. We describe the time dependence of the temperature difference of the cooling object and the environment with an exponential decay function. By measuring the thermal constant tau, we determine the convective heat-transfer coefficient, which is a characteristic constant of the convection system.
Flow characteristics of a channelized debris-flow and implications in numerical modelling: a study case
2012
As it is known, debris flows are characterized by extreme propagation rapidity and by the ability to move high quantity of fluid mass. Furthermore, debris flows are fluid enough to travel long distances and, thus, to cause damage in vast areas, even far from the trigger ones. Debris-flow runout estimations are important for the delineation of potentially hazardous areas. Especially in recent years, several researches have been conducted in order to define predicitive models. But, existing runout estimation methods need input parameters that can be difficult to estimate. Recent advances in theory and in experimental research have allowed the assessment of the physics of the debris flows. On …
Transcriptional Rewiring, Adaptation, and the Role of Gene Duplication in the Metabolism of Ethanol of Saccharomyces cerevisiae
2020
Ethanol is the main by-product of yeast sugar fermentation that affects microbial growth parameters, being considered a dual molecule, a nutrient and a stressor. Previous works demonstrated that the budding yeast arose after an ancient hybridization process resulted in a tier of duplicated genes within its genome, many of them with implications in this ethanol “produce-accumulate-consume” strategy. The evolutionary link between ethanol production, consumption, and tolerance versus ploidy and stability of the hybrids is an ongoing debatable issue. The implication of ancestral duplicates in this metabolic rewiring, and how these duplicates differ transcriptionally, remains unsolved. Here, we …