Blogs

A fateful football injury put Marquese Chriss on path to Warriors

first_imgIt was a fall day in Elk Grove, the suburban town 20 minutes of Sacramento, and Marquese Chriss was going long.The newest Warrior was in eighth grade and playing in a game for the middle school football team. He was a promising tight end. Fast but also long, gangly. Chriss ran a deep route, went up high and sprawled out for the catch but landed awkwardly on his shoulder. The x-ray evidence was not positive: fractured collarbone.Up until that day, all Chriss had wanted to do was play …last_img read more

NMPF supports effort to bring clarity to EPA’s Waters of the U.S. Regulation

first_imgShare Facebook Twitter Google + LinkedIn Pinterest The National Milk Producers Federation (NMPF) told the U.S. Environmental Protection Agency (EPA) that the dairy industry supports a two-step process to roll back the existing Waters of the U.S. (WOTUS) regulation and generate a new policy that provides farmers greater certainty in the future.NMPF has supported efforts by the Trump Administration since January to restart the regulatory process behind the controversial 2015 Waters of the U.S. (WOTUS) rule. NMPF provided comments today to EPA in support of rescinding the 2015 rule so the agency can initiate a new regulatory process defining and regulating groundwater sources. The agency has been soliciting comments on the WOTUS revision process during the past two months.“A fresh start and a more reasonable approach that complies with past Supreme Court rulings will be in the best interests of the environment and dairy farmers,” said Jamie Jonker, NMPF vice president for sustainability and scientific affairs, in comments to EPA.  “We are committed to working with the EPA and the Army Corps of Engineers to find effective ways to protect America’s water supplies.”Rescinding the 2015 policy — which is currently not being enforced because an appeals court suspended it last year, pending the outcome of several lawsuits — is the first step in a two-part process. In the forthcoming second step, EPA will need to propose a new rule that conforms to the various Supreme Court cases impacting definitions for what is considered a water of the U.S.  In NMPF’s letter to EPA, Jonker said that EPA and the Army Corps will need to correct the ambiguity resulting from the 2015 rule’s lack of clarity on key terms and definitions, such as “adjacent,” “floodplain” and “significant nexus.”“The agencies’ new notice-and-comment rulemaking needs to provide dairy farmers with certainty as to what constitutes navigable waters of the United States by clearly complying with the Supreme Court decisions,” NMPF wrote. “We look forward to working with you in the future for the proper clarity that dairy farmers need on WOTUS to continue to meet our shared commitment to clean water,” NMPF wrote.last_img read more

Physicists develop flexible multicell ZnMnO2 battery for printed electronics

first_img(Phys.org) —The market for thin, flexible, printed electronic circuits is potentially huge. Although tremendous advances have been made in printing organic semiconductors like thin-film transistors (TFTs), one of their present limitations is a relatively high operating voltage requirement. 3D printed lithium-ion batteries with acceptable single-cell potentials (~3V) have been previously demonstrated, at least on small scales. The main concerns though, are that even with hermetic packaging, the raw materials for these cells still pose inherent safety and reliability risks. For wearable devices, which are a major application for flexible printed devices, a more versatile technology has been sought. A new study in Applied Physics Letters describes recent experiments with a different battery chemistry—Zn-MnO2. Using special fabrication techniques, a 10-cell series configuration of the battery was able to generate peak voltages of 14 volts, and a capacity of up to 0.8 mA h. © 2013 Phys.org The main incentive to developing printed thin-film batteries is that they would be able to be fabricated on the same production line as the rest of a printed electronic device. Much research has gone into reducing the relatively high potential (10-30V) of solution-phase printed organic TFTs. The fact remains that a lot of the traditional problems of these devices like low mobility, large channel lengths, drain-source shorting, and thick dielectric layers, go away when higher voltages are used. The ability to now make high-potential batteries based on alkaline chemistry, like the Zn-MnO2, removes many of the traditional concerns with lithium batteries.Alkaline batteries are generally less expensive than lithium batteries, and their environmentally friendly raw materials do not need to be hermetically sealed. The cells are printed on commercially available polyvivyl alcohol/cellulose(PAC) membranes. The 100um thick membrane also serves as a separator and a substrate for the Zn and MnO2 electrodes. A hydrophobic fluoropolymer solution (Teflon AF) is printed between the electrodes to reduce electrolyte migration and conduction between neighboring electrodes of different cells. The anode and cathode are printed from solution-based inks composed of conductive additives and binder materials. The cells were connected with a printed silver-based ink.The anode and cathode footprint of the battery, as well as their separation distance, is 1 cm2. The open circuit potential of 14 V is limited mainly by self-discharge of the MnO2 electrode during processing, particularly as a result of the multiple baking steps needed to evaporate solvents. The battery was tested by discharging through a 100 kΩ resistive load. After 7.5 hours, the potential dropped to 10V, which was what was used for the conservatively-set 0.8 mA h capacity.To further characterize their battery, a technique known as electrochemical impedance spectroscopy was used to determine the ohmic resistance (1.20 Ω), and the charge transfer resistance (0.8 Ω). These values are low enough for the individual cells that they do not cause major impedance losses when assembled into a 10-cell device. The researchers also gave the battery a real-word test to demonstrate its performance within an actual printed circuit. They used a ring oscillator circuit made from five simple inverting gates connected head-to-tail. The frequency of an output tap on this circuit depends on supply voltage and delay through the circuit. The ring oscillator test circuit only drew a very low current and the resulting waveform peaked at 13 V on each 10 ms cycle. After 20 minutes of use, no changes in the open circuit potential were detectable, suggesting that simple circuits could be powered for an extended duration. More complex circuits may likely draw much more power than a ring oscillator, but the new Zn-MnO2 battery looks like it will be a good alternative to lithium for many foreseable printed device applications. Journal information: Applied Physics Letters Citation: Physicists develop flexible multicell Zn-MnO2 battery for printed electronics (2013, June 20) retrieved 18 August 2019 from https://phys.org/news/2013-06-physicists-flexible-multicell-zn-mno2-battery.html Explore furthercenter_img Printed Flexible Zn-Mno2 Battery. Credit: A. Gaikwad et. al. Applied Physics Letters Vol 102 Issue 23 More information: A flexible high potential printed battery for powering printed electronics, Appl. Phys. Lett. 102, 233302 (2013); dx.doi.org/10.1063/1.4810974 AbstractMechanically flexible arrays of alkaline electrochemical cells fabricated using stencil printing onto fibrous substrates are shown to provide the necessary performance characteristics for driving ink-jet printed circuits. Due to the dimensions and material set currently required for reliable low-temperature print processing of electronic devices, a battery potential greater than that sourced by single cells is typically needed. The developed battery is a series interconnected array of 10 low resistance Zn-MnO2 alkaline cells, giving an open circuit potential of 14 V. This flexible battery is used to power an ink-jet printed 5-stage complementary ring oscillator based on organic semiconductors. Battery embedded in circuit board demonstrated at Tokyo exhibition This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more