Advances in Repurposing and Recycling of Post-Vehicle-Application Lithium-Ion Batteries

Increased electrification of vehicles has increased the use of lithium-ion batteries for energy storage, and raised the issue of what to do with post-vehicle-application batteries. Three possibilities have been identified: 1) remanufacturing for intended reuse in vehicles; 2) repurposing for non-vehicle, stationary storage applications; and 3) recycling, extracting the precious metals, chemicals and other byproducts. Advances in repurposing and recycling are presented, along with a mathematical model that forecasts the manufacturing capacity needed for remanufacturing, repurposing, and recycling. Results obtained by simulating the model show that up to a 25% reduction in the need for new batteries can be achieved through remanufacturing, that the sum of repurposing and remanufacturing capacity is approximately constant across various scenarios encouraging the sharing of resources, and that the need for recycling capacity will be significant by 2030. A repurposing demonstration shows the use of post-vehicle-application batteries to support a semi-portable recycling platform. Energy is collected from solar panels, and dispensed to electrical devices as required. Recycling may be complicated: lithium-ion batteries produced by different manufacturers contain different active materials, particularly for the cathodes. In all cases, however, the collecting foils used in the anodes are copper, and in the cathodes are aluminum. A common recycling process using relatively low acid concentrations, low temperatures, and short time periods was developed and demonstrated

Using Technology to Develop Preservice Teachers\u27 Reflective Thinking

Developing high-level reflection skills proves troublesome for some preservice teachers. To examine the potential of an online environment for increasing productive reflection, students in three sequential undergraduate education classes responded to regular online prompts. We coded student comments for productive and unproductive reflection, knowledge integration, and analysis of the four aspects of teaching (learners and learning, subject matter knowledge, assessment and instruction ) as described by Davis, Bain, & Harrington (2001). We adapted a scoring approach recommended by Davis & Linn, (2000); Davis (2003) to analyze what aspects of teaching preservice teachers included, emphasized, and integrated when they reflected on their own beliefs about teaching. Discussion examines the utility of online environments for producing productive preservice teacher reflection

The Effects of Urbanization on the Water Balance of the Fishtrap Creek Basin, Northwest Washington and South Central British Columbia

The Fishtrap Creek basin is located in northwest Washington State and south central British Columbia. Land use in the basin is predominantly agricultural. Moderate urbanization in the past thirty-five years has increased impervious surface area in the basin from 1.8 to 8.0 percent. Monthly water balances were derived in order to quantify the effect of changing land use on the discharge of Fishtrap Creek. Stream discharges calculated from these water balances, constructed for 1952 through 1953 and 1987 through 1988, compare well with measured monthly and annual stream discharges. The favorable comparison indicates that the water- balance variables are in general reliable. However, in months following long periods of dry weather, calculated discharge was much higher than measured discharge. The discrepancy is probably because the standard water balance method does not account for water stored in the vadose zone below the rooting depth of the vegetation or the time lag required for the water to infiltrate through this zone and into the groundwater reservoir. To interpret the results of changing land use on the discharge of Fishtrap Creek, a hypothetical water balance was calculated incorporating the climatic data for 1952 through 1953 and the land use as of 1988. In effect, climate was held constant while land use changed with time. The hypothetical water balance predicted that, as a result of changing land use, a 7.8 percent increase in annual stream discharge would have occurred if the 1952 through 1953 climate had occurred again in 1987 through 1988. Of this 7.8 percent increase, 2.7 percent is due to increased overland flow and 5.1 percent to increased groundwater discharge. The predictions based on the hypothetical water balance are supported by comparison of actual storm events. For comparable storms, stream discharge was higher in the 1987 - 1988 period than in 1952 - 1953

Open-Source Flight Computer Platform for CubeSats

BeaverCube is a 3U CubeSat in development by the Space Systems Development capstone class and STARLab at MIT. The satellite will serve as a testing platform for an electrospray thruster developed by AccionSystems and host a payload with a mvBlueFox visual imaging camera and two FLIR Boson infrared cameras. The BeaverCube Flight Computer (BFC) is designed to serve as the power and data interface for the entire CubeSat bus, and incorporates a Raspberry Pi compute module as the central processor. Key design objectives for the BFC include a novel fault detection, isolation and response (FDIR) system to improve CubeSat reliability, the capability to interface with devices and power on the bus through standardized connectors, and a high data rate imaging payload. The outcome of this design is a flight computer able to recover autonomously (without ground intervention) from software faults or non-destructive hardware failures within 90 seconds. Two onboard computers and four data storage cards provide mission continuity if a destructive event occurs. The BFC supports several common data protocols including USB 2.0 for rapid payload data transfer, which allows the BFC to be readily integrated into many CubeSat systems. The BFC open-source repository will be made public following testing on the first revision prototype so this board design is available for future CubeSat missions

Stepwise Model Fitting and Statistical Inference: Turning Noise into Signal Pollution

Statistical inference based on stepwise model selection is applied regularly in ecological, evolutionary, and behavioral research. In addition to fundamental shortcomings with regard to finding the “best” model, stepwise procedures are known to suffer from a multiple‐testing problem, yet the method is still widely used. As an illustration of this problem, we present results of a simulation study of artificial data sets of uncorrelated variables, with two to 10 predictor variables and one dependent variable. We then compared results from stepwise regression with a regression model in which all predictor variables were entered simultaneously. These analyses clearly demonstrate that significance tests based on stepwise procedures lead to greatly inflated Type I error rates (i.e., the probability of erroneously rejecting a true null hypothesis). By using a simple simulation design, our study amplifies previous warnings about using stepwise procedures, and we follow others in recommending that biologists refrain from applying these methods.Anthropolog

Phylogenetic Targeting of Research Effort in Evolutionary Biology

Many questions in comparative biology require that new data be collected, either to build a comparative database for the first time or to augment existing data. Given resource limitations in collecting data, the question arises as to which species should be studied to increase the size of comparative data sets. By taking hypotheses, existing data relevant to the hypotheses, and a phylogeny, we show that a method of “phylogenetic targeting” can systematically guide data collection while taking into account potentially confounding variables and competing hypotheses. Phylogenetic targeting selects potential candidates for future data collection, using a flexible scoring system based on differences in pairwise comparisons. We used simulations to assess the performance of phylogenetic targeting, as compared with the less systematic approach of randomly selecting species (as might occur when data have been collected without regard to phylogeny and variation in the traits of interest). The simulations revealed that phylogenetic targeting increased the statistical power to detect correlations and that power increased with the number of species in the tree, even when the number of species studied was held constant. We also developed a Web‐based computer program called PhyloTargeting to implement the approach (http://phylotargeting.fas.harvard.edu).Human Evolutionary Biolog

Predation and the Phasing of Sleep: An Evolutionary Individual-based Model

All mammals thus far studied sleep, yet important questions remain concerning the ecological factors that influence sleep patterns. Here, we developed an evolutionary individual-based model to investigate the effect of predation pressure on prey sleep. We investigated three ecological conditions, including one that assumed a dynamic interaction between predator and prey behaviour. In condition 1, we found that monophasic predators (i.e. with one sleep bout per 24 h) select for monophasic prey that sleep perfectly out of phase with predators. In condition 2, predators were monophasic but the safety of prey varied as a function of their activity (sleeping versus awake). In this condition, the prey adjusted their sleeping behaviour to lower the risk of predation. Finally, in condition 3, we modelled a more dynamic interaction between predator and prey, with predator activity dependent on prey activity in the previous hour. In this scenario, the prey adjusted their behaviour relative to one another, resulting in either greater or lesser synchrony in prey as a function of predator searching behaviour. Collectively, our model demonstrates that predator behaviour can have a strong influence on prey sleep patterns, including whether prey are monophasic or polyphasic (i.e. with many sleep bouts per 24 h). The model further suggests that the timing of sleep relative to predator behaviour may depend strongly on how other potential prey partition the activity period.Human Evolutionary Biolog

Rapid Evolution of Social Learning

Culture is widely thought to be beneficial when social learning is less costly than individual learning and thus may explain the enormous ecological success of humans. Rogers (1988. Does biology constrain culture. Am. Anthropol. 90: 819–831) contradicted this common view by showing that the evolution of social learning does not necessarily increase the net benefits of learned behaviours in a variable environment. Using simulation experiments, we re-analysed extensions of Rogers' model after relaxing the assumption that genetic evolution is much slower than cultural evolution. Our results show that this assumption is crucial for Rogers' finding. For many parameter settings, genetic and cultural evolution occur on the same time scale, and feedback effects between genetic and cultural dynamics increase the net benefits. Thus, by avoiding the costs of individual learning, social learning can increase ecological success. Furthermore, we found that rapid evolution can limit the evolution of complex social learning strategies, which have been proposed to be widespread in animals.Human Evolutionary Biolog

Investigating the Impact of Observation Errors on the Statistical Performance of Network-based Diffusion Analysis

Experiments in captivity have provided evidence for social learning, but it remains challenging to demon- strate social learning in the wild. Recently, we developed network-based diffusion analysis (NBDA; 2009) as a new approach to inferring social learning from observational data. NBDA fits alternative models of asocial and social learning to the diffusion of a behavior through time, where the potential for social learning is related to a social network. Here, we investigate the performance of NBDA in relation to variation in group size, network heterogeneity, observer sampling errors, and duration of trait diffusion. We find that observation errors, when severe enough, can lead to increased Type I error rates in detecting social learning. However, elevated Type I error rates can be prevented by coding the observed times of trait acquisition into larger time units. Collectively, our results provide further guidance to applying NBDA and demonstrate that the method is more robust to sampling error than initially expected. Supplemental materials for this article may be downloaded from http:// lb.psychonomic-journals.org/content/supplemental.Human Evolutionary Biolog