A Paradigmatic Review of Integral Ecology

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Call for Papers

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What Works? Implementing Section 503. Survey Text and Flow

This survey was fielded to representatives of organizations that are federal contractors. Desired respondents were specifically human resources, compliance, or legal professionals who know about their organization\u27s efforts to implement the recent regulations for Section 503 of the Rehabilitation Act. The survey asked respondents to anonymously provide information about organizational characteristics, affirmative action goals related to disability, use of the Voluntary Self ID form to collect disability status information, and internal practices and procedures their organization had found helpful or challenging

Guest Artist Recitals

A faculty and guest artist recital performed at the UNT College of Music Recital Hall

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

International audienceSolid block polymer electrolytes are promising candidates for the development of high energy density rechargeable lithium metal based batteries. All solid-state batteries comprising lithium metal negative electrode and lithium iron phosphate (LiFePO4) composite positive electrode were assembled. A polystyrene-b-poly(ethylene oxide) (SEO) copolymer doped with a lithium salt was used as the electrolyte. After cycling the batteries, the reason for capacity fade and failure was determined by imaging the batteries using synchrotron hard X-ray microtomography. These experiments revealed partial delamination of the lithium foil and the block copolymer electrolyte layer. The void volume between the foil and electrolyte layer obtained after 40 to 90 cycles is comparable to volume change in the battery during one cycle. A simple model to account for the effect of delamination on current density in the battery is presented. Capacity fade and battery failures observed in our experiments are consistent with this model. No evidence of lithium dendrite formation was found. In contrast, cycled lithium-lithium symmetric cells with the same polymer electrolyte at the same current density failed due to dendrite formation. No evidence of delamination was found in these cells

Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes.

Failure caused by dendrite growth in high-energy-density, rechargeable batteries with lithium metal anodes has prevented their widespread use in applications ranging from consumer electronics to electric vehicles. Efforts to solve the lithium dendrite problem have focused on preventing the growth of protrusions from the anode surface. Synchrotron hard X-ray microtomography experiments on symmetric lithium-polymer-lithium cells cycled at 90 °C show that during the early stage of dendrite development, the bulk of the dendritic structure lies within the electrode, underneath the polymer/electrode interface. Furthermore, we observed crystalline impurities, present in the uncycled lithium anodes, at the base of the subsurface dendritic structures. The portion of the dendrite protruding into the electrolyte increases on cycling until it spans the electrolyte thickness, causing a short circuit. Contrary to conventional wisdom, it seems that preventing dendrite formation in polymer electrolytes depends on inhibiting the formation of subsurface structures in the lithium electrode

What Works? Implementing Section 503. Survey Text and Flow

This survey was fielded to representatives of organizations that are federal contractors. Desired respondents were specifically human resources, compliance, or legal professionals who know about their organization's efforts to implement the recent regulations for Section 503 of the Rehabilitation Act. The survey asked respondents to anonymously provide information about organizational characteristics, affirmative action goals related to disability, use of the Voluntary Self ID form to collect disability status information, and internal practices and procedures their organization had found helpful or challenging.DA_Section503_Survey_Final.pdf: 96 downloads, before Oct. 1, 2020