2014 Fed Challenge Script: Current State of the Economy

Good afternoon everyone and thank you for having us here today. Though the recession began in 2007 and officially ended in 2009, recovery has been painfully slow. GDP growth has been insufficient to close the output gap, there continues to be slack in the labor market and inflation has stabilized below the Federal Reserve percent target. We are not meeting our dual mandate of full employment and stable prices even 6 years after the end of the recession. Despite some signs of strengthening in the economy during the past year, we do not believe that economy is on a self-sustaining path of recovery. Furthermore, the monetary policy actions taken by the Fed thus far to pull us out of the Great Recession have been insufficient. We propose a substantial strengthening of the our forward guidance; specifically, a commitment not to raise the federal funds rate until nominal GDP has returned to a path that we consider consistent with the dual mandate. [excerpt

Particulate and Gas Phase Hydrocarbon Emissions from Partially Premixed Low Temperature Compression Ignition Combustion of Biodiesel.

The research presented in this document examines the results of melding three diesel engine emissions reduction methodologies: partially premixed low temperature combustion (LTC); the use of alternative, biodiesel fuel; and aftertreatment using a diesel oxidation catalyst (DOC). It shows how alternative fuels and novel combustion strategies complement each other on one hand and create new emissions challenges on the other. Partially premixed LTC simultaneously reduces soot and NOX emissions for both biodiesel and petroleum diesel fuels. The use of biodiesel in LTC has added benefits of lowering total hydrocarbon (THC) and CO emissions and reducing soot emissions to near undetectable levels. Light hydrocarbon species like ethylene emitted from biodiesel LTC as a fraction of THC are higher independent of ignition delay indicating that biodiesel burns more completely and results in less unburned hydrocarbon (UHC) emissions than petroleum diesel. However, the generally higher gas-phase UHC emissions from LTC compared to conventional combustion results in excessive particulate matter (PM) for biodiesel due to heterogeneous condensation of methyl esters onto soot particles after dilution with atmospheric air. In the work presented here, this condensation process resulted in over an order of magnitude increase in PM emissions for B100 in a late injection LTC condition (LLTC) compared to petroleum-derived fuels. For an early injection LTC (ELTC) condition, PM emissions were almost 100 times higher than the diesel fuels tested. Low vapor pressure methyl esters making up biodiesel have a near 95% conversion from the gas to the particle phase with an undiluted exhaust UHC concentration of 1000 ppm for a 10:1 dilution ratio and 47°C collection temperature. Although the use of biodiesel in LTC increases PM emissions significantly following dilution of the raw exhaust, the results of this work indicate that 80% of UHC in the exhaust is oxidized by a standard DOC with inlet temperature of 240°C. Unfortunately, the remaining unburned biodiesel left unconverted still significantly contributes to the PM following dilution. Methyl esters were found to be the primary species contributing to the higher total organic fraction (>90%) on the PM for biodiesel compared with diesel LLTC following a DOC.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75997/1/wnorthro_1.pd

Experimental investigation of spark-assisted compression-ignition with ammonia-hydrogen blends

Carbon-free emissions and stable operation of ammonia-fueled internal combustion engines have been demonstrated in recent studies through combustion strategies suited to the fuel’s unique properties. High ignition energy and slow flame speed of ammonia are typically compensated for by hydrogen addition and/or enhanced ignition systems while the high octane rating of ammonia allows high compression ratio. The experimental study in this work investigates the performance of ammonia in spark-assisted compression-ignition (SACI) mode, where the cylinder charge is spark ignited and a subsequent auto-ignition event results in a faster burn and more ideal combustion phasing. The high-compression ratio engine was fueled by 100% anhydrous ammonia or blends with small quantities of hydrogen (2.5% and 5% by volume). Fuels were port-injected for a homogeneous intake charge mixture at stoichiometric equivalence ratio. Two different engine speeds were tested at several intake temperatures and spark timings. All cases showed an inflection point in the apparent heat release rate (AHRR) followed by more rapid rate of heat release, signaling the onset of auto-ignition. Blending hydrogen in the fuel benefited gross indicated mean effective pressure (gIMEP) at maximum brake torque (MBT) timing, but pure ammonia fuel was more stable across a wide range of spark timings and intake temperatures. Burn durations in the present study were similar to those of conventional SI engines fueled by gasoline indicating that the combustion enhancement of SACI compensated for the lower flame speed of ammonia. The control of SI percent, defined as the fraction of heat release before auto-ignition compared to the total heat release, is shown to be strongly related to the sensitivity of auto-ignition timing to spark timing. Unburned ammonia emissions are hypothesized to be primarily driven by unburned gases trapped in the crevices and are mitigated slightly through blending hydrogen in the fuel or by increasing intake temperature. However, the addition of hydrogen and increasing intake temperature led to increased nitric oxide (NO) emissions. Of primary concern because of its potent global warming potential, nitrous oxide (N2O) did not show a clear trend with fuel hydrogen content or intake temperature, but definitively increased for the higher engine speed

Synthesis gas as a fuel for internal combustion engines in transportation

© 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).The adverse environmental impact of fossil fuel combustion in engines has motivated research towards using alternative low-carbon fuels. In recent years, there has been an increased interest in studying the combustion of fuel mixtures consisting mainly of hydrogen and carbon monoxide, referred to as syngas, which can be considered as a promising fuel toward cleaner combustion technologies for power generation. This paper provides an extensive review of syngas production and application in internal combustion (IC) engines as the primary or secondary fuel. First, a brief overview of syngas as a fuel is presented, introducing the various methods for its production, focusing on its historical use and summarizing the merits and drawbacks of using syngas as a fuel. Then its physicochemical properties relevant to IC engines are reviewed, highlighting studies on the fundamental combustion characteristics, such as ignition delay time and laminar and turbulent flame speeds. The main body of the paper is devoted to reviewing the effect of syngas utilization on performance and emissions characteristics of spark ignition (SI), compression ignition (CI), homogeneous charge compression ignition (HCCI), and advanced dual-fuel engines such as reactivity-controlled compression ignition (RCCI) engines. Finally, various on-board fuel reforming techniques for syngas production and use in vehicles are reviewed as a potential route towards further increases in efficiency and decreases in emissions of IC engines. These are then related to the research reported on the behavior of syngas and its blends in IC engines. It was found that the selection of the syngas production method, choice of the base fuel for reforming, its physicochemical properties, combustion strategy, and engine combustion system and operating conditions play critical roles in dictating the potential advantages of syngas use in IC engines. The discussion of the present review paper provides valuable insights for future research on syngas as a possible fuel for IC engines for transport.Peer reviewe

A Survey on Solving and Discovering Differential Equations Using Deep Neural Networks

Ordinary and partial differential equations (DE) are used extensively in scientific and mathematical domains to model physical systems. Current literature has focused primarily on deep neural network (DNN) based methods for solving a specific DE or a family of DEs. Research communities with a history of using DE models may view DNN-based differential equation solvers (DNN-DEs) as a faster and transferable alternative to current numerical methods. However, there is a lack of systematic surveys detailing the use of DNN-DE methods across physical application domains and a generalized taxonomy to guide future research. This paper surveys and classifies previous works and provides an educational tutorial for senior practitioners, professionals, and graduate students in engineering and computer science. First, we propose a taxonomy to navigate domains of DE systems studied under the umbrella of DNN-DE. Second, we examine the theory and performance of the Physics Informed Neural Network (PINN) to demonstrate how the influential DNN-DE architecture mathematically solves a system of equations. Third, to reinforce the key ideas of solving and discovery of DEs using DNN, we provide a tutorial using DeepXDE, a Python package for developing PINNs, to develop DNN-DEs for solving and discovering a classic DE, the linear transport equation.Comment: Under review for ACM Computing Surveys journal. 29 page

Introduction to special issue on Webster

John Webster’s Theater of (Dis)obedience and Damnation: A collection of essays exploring the forms and functions of violence, evil, and social realities in Webster's drama

Can Automated Vehicles "See" in Minnesota? Ambient Particle Effects on LiDAR

(c)1035427This project will use a combination of laboratory experimentation and road demonstrations to better understand the reduction of LiDAR signal and object detection capability under adverse weather conditions found in Minnesota. It will also lead to concepts to improve LiDAR systems to adapt to such conditions through better signal processing image recognition software

The Development of a Standardized Protocol for Quantifying Equestrian Eventing Cross-Country Ground

The ground has long been cited as a key contributing factor for injury risk in the cross-country phase of eventing. The current study aimed to develop a practically useful standardized protocol for measuring eventing cross country ground. Data collection was split into three phases: Phase 1 (Validation), Phase 2 (Expansion of data set), and Phase 3 (Threshold establishment). During Phase 1, data from nine event courses were collected using an Orono Biomechanical Surface Tester (OBST), Vienna Surface Tester (VST), Lang Penetrometer, Going Stick, and moisture meter. Using linear regression, 80% of the variability in cushioning measured with the OBST was predicted from moisture and VST measurements (p < 0.001). In Phase 2, objective data from 81 event courses and subjective assessments from 180 event riders were collected. In Phase 3, k-means cluster analysis was used to classify the courses into ten clusters based on average course measurements of moisture, cushioning, firmness, stiffness, depth, and coefficient of restitution. Based on cluster membership, course average subjective data (16 courses) were compared using a General Linear Model. Significant differences (p < 0.05) in subjective impact firmness (p = 0.038) and subjective cushioning (p = 0.010) were found between clusters. These data and cluster thresholds provide an event course baseline for future comparisons