Physical and Mechanical Properties of LoVAR: A New Lightweight Particle-Reinforced Fe-36Ni Alloy

Fe-36Ni is an alloy of choice for low thermal expansion coefficient (CTE) for optical, instrument and electrical applications in particular where dimensional stability is critical. This paper outlines the development of a particle-reinforced Fe-36Ni alloy that offers reduced density and lower CTE compared to the matrix alloy. A summary of processing capability will be given relating the composition and microstructure to mechanical and physical properties

The Biot-Savart operator and electrodynamics on subdomains of the three-sphere

We study steady-state magnetic fields in the geometric setting of positive curvature on subdomains of the three-dimensional sphere. By generalizing the Biot-Savart law to an integral operator BS acting on all vector fields, we show that electrodynamics in such a setting behaves rather similarly to Euclidean electrodynamics. For instance, for current J and magnetic field BS(J), we show that Maxwell's equations naturally hold. In all instances, the formulas we give are geometrically meaningful: they are preserved by orientation-preserving isometries of the three-sphere. This article describes several properties of BS: we show it is self-adjoint, bounded, and extends to a compact operator on a Hilbert space. For vector fields that act like currents, we prove the curl operator is a left inverse to BS; thus the Biot-Savart operator is important in the study of curl eigenvalues, with applications to energy-minimization problems in geometry and physics. We conclude with two examples, which indicate our bounds are typically within an order of magnitude of being sharp.Comment: 24 pages (was 28 pages) Revised to include a new introduction, a detailed example, and results about helicity; other changes for readabilit

Physical and Mechanical Properties of LoVAR: A New Lightweight Particle-Reinforced Fe-36Ni Alloy

Fe-36Ni is an alloy of choice for low thermal expansion coefficient (CTE) for optical, instrument and electrical applications in particular where dimensional stability is critical. This paper outlines the development of a particle-reinforced Fe-36Ni alloy that offers reduced density and lower CTE compared to the matrix alloy. A summary of processing capability will be given relating the composition and microstructure to mechanical and physical properties

Effectiveness of implementing a wake up and breathe program on sedation and delirium in the ICU

OBJECTIVES: Mechanically ventilated critically ill patients receive significant amounts of sedatives and analgesics that increase their risk of developing coma and delirium. We evaluated the impact of a "Wake-up and Breathe Protocol" at our local ICU on sedation and delirium. DESIGN: A pre/post implementation study design. SETTING: A 22-bed mixed surgical and medical ICU. PATIENTS: Seven hundred two consecutive mechanically ventilated ICU patients from June 2010 to January 2013. INTERVENTIONS: Implementation of daily paired spontaneous awakening trials (daily sedation vacation plus spontaneous breathing trials) as a quality improvement project. MEASUREMENTS AND MAIN RESULTS: After implementation of our program, there was an increase in the mean Richmond Agitation Sedation Scale scores on weekdays of 0.88 (p < 0.0001) and an increase in the mean Richmond Agitation Sedation Scale scores on weekends of 1.21 (p < 0.0001). After adjusting for age, race, gender, severity of illness, primary diagnosis, and ICU, the incidence and prevalence of delirium did not change post implementation of the protocol (incidence: 23% pre vs 19.6% post; p = 0.40; prevalence: 66.7% pre vs 55.3% post; p = 0.06). The combined prevalence of delirium/coma decreased from 90.8% pre protocol implementation to 85% postimplementation (odds ratio, 0.505; 95% CI, 0.299-0.853; p = 0.01). CONCLUSIONS: Implementing a "Wake Up and Breathe Program" resulted in reduced sedation among critically ill mechanically ventilated patients but did not change the incidence or prevalence of delirium

The Global Durum Wheat Panel (GDP): An International Platform to Identify and Exchange Beneficial Alleles

Representative, broad and diverse collections are a primary resource to dissect genetic diversity and meet pre-breeding and breeding goals through the identification of beneficial alleles for target traits. From 2,500 tetraploid wheat accessions obtained through an international collaborative effort, a Global Durum wheat Panel (GDP) of 1,011 genotypes was assembled that captured 94-97% of the original diversity. The GDP consists of a wide representation of Triticum turgidum ssp. durum modern germplasm and landraces, along with a selection of emmer and primitive tetraploid wheats to maximize diversity. GDP accessions were genotyped using the wheat iSelect 90K SNP array. Among modern durum accessions, breeding programs from Italy, France and Central Asia provided the highest level of genetic diversity, with only a moderate decrease in genetic diversity observed across nearly 50 years of breeding (1970-2018). Further, the breeding programs from Europe had the largest sets of unique alleles. LD was lower in the landraces (0.4 Mbp) than in modern germplasm (1.8 Mbp) at r 2 = 0.5. ADMIXTURE analysis of modern germplasm defined a minimum of 13 distinct genetic clusters (k), which could be traced to the breeding program of origin. Chromosome regions putatively subjected to strong selection pressure were identified from fixation index (F st ) and diversity reduction index (DRI) metrics in pairwise comparisons among decades of release and breeding programs. Clusters of putative selection sweeps (PSW) were identified as co-localized with major loci controlling phenology (Ppd and Vrn), plant height (Rht) and quality (gliadins and glutenins), underlining the role of the corresponding genes as driving elements in modern breeding. Public seed availability and deep genetic characterization of the GDP make this collection a unique and ideal resource to identify and map useful genetic diversity at loci of interest to any breeding program

Improving delirium care in the intensive care unit: The design of a pragmatic study

<p>Abstract</p> <p>Background</p> <p>Delirium prevalence in the intensive care unit (ICU) is high. Numerous psychotropic agents are used to manage delirium in the ICU with limited data regarding their efficacy or harms.</p> <p>Methods/Design</p> <p>This is a randomized controlled trial of 428 patients aged 18 and older suffering from delirium and admitted to the ICU of Wishard Memorial Hospital in Indianapolis. Subjects assigned to the intervention group will receive a multicomponent pharmacological management protocol for delirium (PMD) and those assigned to the control group will receive no change in their usual ICU care. The primary outcomes of the trial are (1) delirium severity as measured by the Delirium Rating Scale revised-98 (DRS-R-98) and (2) delirium duration as determined by the Confusion Assessment Method for the ICU (CAM-ICU). The PMD protocol targets the three neurotransmitter systems thought to be compromised in delirious patients: dopamine, acetylcholine, and gamma-aminobutyric acid. The PMD protocol will target the reduction of anticholinergic medications and benzodiazepines, and introduce a low-dose of haloperidol at 0.5-1 mg for 7 days. The protocol will be delivered by a combination of computer (artificial intelligence) and pharmacist (human intelligence) decision support system to increase adherence to the PMD protocol.</p> <p>Discussion</p> <p>The proposed study will evaluate the content and the delivery process of a multicomponent pharmacological management program for delirium in the ICU.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00842608">NCT00842608</a></p

Engineering Bipolar Interfaces for Water Electrolysis Using Earth-Abundant Anodes.

Developing efficient and low-cost water electrolyzers for clean hydrogen production to reduce the carbon footprint of traditional hard-to-decarbonize sectors is a grand challenge toward tackling climate change. Bipolar-based water electrolysis combines the benefits of kinetically more favorable half-reactions and relatively inexpensive cell components compared to incumbent technologies, yet it has been shown to have limited performance. Here, we develop and test a bipolar-interface water electrolyzer (BPIWE) by combining an alkaline anode porous transport electrode with an acidic catalyst-coated membrane. The role of TiO2 as a water dissociation (WD) catalyst is investigated at three representative loadings, which indicates the importance of balancing ionic conductivity and WD activity derived from the electric field for optimal TiO2 loading. The optimized BPIWE exhibits negligible performance degradation up to 500 h at 400 mA cm-2 fed with pure water using earth-abundant anode materials. Our experimental findings provide insights into designing bipolar-based electrochemical devices

Design and operating principles for high-performing anion exchange membrane water electrolyzers

Anion-exchange-membrane water electrolyzers (AEMWEs) provide a promising pathway to utilize low-carbon renewable electricity to produce clean hydrogen at high efficiency and purity, while maintaining low system costs compared to incumbent technologies. Though significant progress has been made in developing membranes and catalysts, AEMWEs still require better performance and durability to realize widespread deployment. Here, we overcome these challenges by decoupling anode and cathode polarization behavior via integration of a reference electrode in the membrane-electrode assembly. This measurement identified that the mass-transport losses dominate the cathode overpotential if feeding with electrolytes, while kinetic losses dominate the anode overpotential. These losses are mitigated by varying electrode properties and operating strategies, where a more hydrophobic, optimal loaded cathode, a high porosity anode, and operating with the cathode dry exhibited the best performance. These findings eventually enabled achieving a high-performing and durable complete PGM-free AEMWE operating at 1.5 A cm−2 for over 500 h with negligible degradation, demonstrating significant progress for AEMWEs

Pathways Toward Efficient and Durable Anion Exchange Membrane Water Electrolyzers Enabled By Electro‐Active Porous Transport Layers

Green hydrogen, produced via water electrolysis using renewable electricity, will play a crucial role in decarbonizing industrial and heavy-duty transportation sectors. Anion exchange membrane water electrolyzers (AEMWEs) can overcome many of the performance and cost limitations of incumbent technologies, however, still suffer from durability challenges due to oxidative instability of anion-exchange ionomers. Herein, the use of an electro-active porous transport layer as anode (PTL-electrode) is demonstrated to enable efficient and durable AEMWEs. The stainless-steel PTL-electrodes are shown to have superior performance and durability compared to traditional catalyst layers containing ionomer and nanoparticle catalysts. An AEMWE cell operating at 2&nbsp;A&nbsp;cm−2 for over 600&nbsp;h exhibited a degradation rate of just 5&nbsp;µV&nbsp;h−1. During operation, the surface composition of the stainless steel transforms into a mixture of iron and nickel oxyhydroxides, contributing to enhanced oxygen-evolution reaction activity. The combination of experimental work and modeling elucidates how the bulk structure of the PTL-electrode offers an additional design dimension to further improve electrolyzer performance. Lastly, a surface modification strategy is applied to a PTL-electrode to achieve an even higher performing AEMWE (2.3&nbsp;vs 2.0&nbsp;A&nbsp;cm−2 at 1.8&nbsp;V). Overall, this work lays out pathways toward more efficient, durable, and affordable AEMWEs

Pure-Water-Fed Forward-Bias Bipolar Membrane CO2 Electrolyzer

Coupling renewable electricity to reduce carbon dioxide (CO2) electrochemically into carbon feedstocks offers a promising pathway to produce chemical fuels sustainably. While there has been success in developing materials and theory for CO2 reduction, the widespread deployment of CO2 electrolyzers has been hindered by challenges in the reactor design and operational stability due to CO2 crossover and (bi)carbonate salt precipitation. Herein, we design asymmetrical bipolar membranes assembled into a zero-gap CO2 electrolyzer fed with pure water, solving both challenges. By investigating and optimizing the anion-exchange-layer thickness, cathode differential pressure, and cell temperature, the forward-bias bipolar membrane CO2 electrolyzer achieves a CO faradic efficiency over 80% with a partial current density over 200 mA cm-2 at less than 3.0 V with negligible CO2 crossover. In addition, this electrolyzer achieves 0.61 and 2.1 mV h-1 decay rates at 150 and 300 mA cm-2 for 200 and 100 h, respectively. Postmortem analysis indicates that the deterioration of catalyst/polymer-electrolyte interfaces resulted from catalyst structural change, and ionomer degradation at reductive potential shows the decay mechanism. All these results point to the future research direction and show a promising pathway to deploy CO2 electrolyzers at scale for industrial applications