The Ethics of Eating Meat

I explore the ethical issues involved in eating meat

Electrical Energy Storage Using Fuel Cell Technology

The goal of this project was to design three different energy storage systems utilizing reversible solid oxide fuel cells. Two of the systems use gaseous feed stocks and require storage for the gas produced by electrolysis. In the third design, molten antimony oxide is reduced to pure antimony during electrolysis rather than storing the energy in a gas. The three systems discussed in this report use electric power during off-peak demand hours to electrolyze a chemical feedstock. The resulting products are then stored for use during peak demand time in fuel cell operation. The systems were designed to store 1 MW of electrical power over a 12 hour period of off-peak demand and release power during a 12 hour period of peak demand. In the two gaseous systems, the fuel cell is made of an yttria-stabilized-zirconia (YSZ) electrolyte with porous nickel at the anode and YSZ-LaMnO3 composite at the cathode. In the electrolysis of steam to form hydrogen, the hydrogen is stored in pressurized vessels at 100 psi. During fuel cell mode, the hydrogen gas is oxidized in the fuel cell to form water, which is again stored for use in electrolysis the following day. The operating temperature for both electrolysis and fuel cell operation is 1472°F. The overall efficiency for the hydrogen system is 52.4%, with the main losses occurring as heat supplied to the electrolyzer. The second design electrolyzes a mixture of steam to hydrogen and carbon dioxide to carbon monoxide at 1292°F and 147 psia. The resulting syngas is fed through a methanation reactor to produce a methane rich stream. The overall efficiency of the methane-based system is 55.7%, with the main losses coming from compression and heating for electrolysis mode. The molten antimony fuel cell uses an equimolar mixture of antimony and antimony trioxide as the feedstock for electrolysis. The electric current in the electrolyzer reduces the antimony trioxide to form a stream of pure molten antimony. Both the electrolyzer and fuel cell operate isothermally at 1292°F and 14.7 psia. The overall efficiency for the antimony design is 53.7%, with the main losses coming from heat supplied to the electrolyzer. For profitability analysis, off peak electricity was priced at $0.06/kWh and peak power was priced at$0.20/kWh. Under these optimistic assumptions, the return on investment (ROI) for the hydrogen design was calculated to be -26.1%. For the methane system, the ROI was calculated to be -19.2%. For the antimony case, the ROI was found to be -34.2%. These designs serve as a framework for future work with electrical energy storage. However, we believe that with improvements in system efficiency and reductions in the initial capital investment, future reversible fuel cell systems will be profitable and competitive with other forms of electrical energy storage

The Importance of Discovery in Children's Causal Learning from Interventions

Four-year-olds were more accurate at learning causal structures from their own actions when they were allowed to act first and then observe an experimenter act, as opposed to observing first and then acting on the environment. Children who discovered the causal efficacy of events (as opposed to confirming the efficacy of events that they observed another discover) were also more accurate than children who only observed the experimenter act on the environment; accuracy in the confirmation and observation conditions was at similar levels. These data suggest that while children learn from acting on the environment, not all self-generated action produces equivalent causal learning

Constructing Science

An examination of children's causal reasoning capacities and how those capacities serve as the foundation of their scientific thinking. Young children have remarkable capacities for causal reasoning, which are part of the foundation of their scientific thinking abilities. In Constructing Science, Deena Weisberg and David Sobel trace the ways that young children's sophisticated causal reasoning abilities combine with other cognitive, metacognitive, and social factors to develop into a more mature set of scientific thinking abilities. Conceptualizing scientific thinking as the suite of skills that allows people to generate hypotheses, solve problems, and explain aspects of the world, Weisberg and Sobel argue that understanding how this capacity develops can offer insights into how we can become a more scientifically literate society. Investigating the development of causal reasoning and how it sets the stage for scientific thinking in the elementary school years and beyond, Weisberg and Sobel outline a framework for understanding how children represent and learn causal knowledge and identify key variables that differ between causal reasoning and scientific thinking. They present empirical studies suggesting ways to bridge the gap between causal reasoning and scientific thinking, focusing on two factors: contextualization and metacognitive thinking abilities. Finally, they examine children's explicit understanding of such concepts as science, learning, play, and teaching

Developmental Trajectories in Diagnostic Reasoning: Understanding Data Are Confounded Develops Independently of Choosing Informative Interventions to Resolve Confounded Data

Two facets of diagnostic reasoning related to scientific thinking are recognizing the difference between confounded and unconfounded evidence and selecting appropriate interventions that could provide learners the evidence necessary to make an appropriate causal conclusion (i.e., the control-of-variables strategy). The present study investigates both these abilities in 3- to 6-year-old children (N = 57). We found both competence and developmental progress in the capacity to recognize that evidence is confounded. Similarly, children performed above chance in some tasks testing for the selection of a controlled test of a hypothesis. However, these capacities were unrelated, suggesting that preschoolers' nascent understanding of the control-of-variables strategy may not be driven by a metacognitive understanding that confounded evidence does not support a unique causal conclusion, and requires further investigation