Site Conversion and Field Performance of an Ultra-Low Emissions Combustion System for the MS7EA Gas Turbine

2008 ◽  
Author(s):  
Jeffrey A. Benoit
Keyword(s):  
United States ◽  
Performance Optimization ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Field Performance ◽  
The United States ◽  
Diffusion Combustion ◽  
Combustion System ◽  
Full Load ◽  
Low Levels

Increasingly restrictive emission regulations for gas turbines are driving key technology decisions across the United States and Europe. For example, in Texas, United States, regulations are forcing permit holders in certain non-attainment areas to ratchet down industrial oxides of nitrogen (NOx) emission levels by over 80% by 2008. Improvements today in the technology of lean pre-mix combustion for gas turbines can result in reduction of NOx and carbon monoxide (CO) emissions to ultra-low levels without using Selective Catalytic Reduction (SCR’s) or Oxidation Catalysts (OCAT’s); and often provides the end user with the most cost effective solution to addressing these requirements. This paper describes the demonstrated current field performance of a dry, lean-premixed combustion system developed for direct replacement in MS7E/EA gas turbines previously configured with either the OEM’s DLN-1 combustion system or converted from a standard diffusion combustion system. The LEC-III® combustion system, developed by Power Systems Mfg. LLC (PSM), owned by Alstom, has proven sub-4ppm NOx and single digit CO emissions levels over the entire premix load operating range with natural gas fuel, from full load down to below 55% of full load conditions in customer machines. A recent conversion effort completed by PSM in 2006 & 2007 now has five gas turbines currently operating at a Texas industrial power producer operating at below 4ppm NOx with the LEC-III system. The conversion scope will also be detailed. Dynamic pressure sensing instrumentation was installed on each combustion chamber to measure and record combustion dynamic oscillations or “noise” to optimize fuel splits within each combustor. Rugged construction and performance optimization enable the dynamics to be maintained within acceptable limits to ensure extended service intervals of over 16,000 equivalent fired hours. Detailed field-installed emissions results are provided for this Frame 7E/EA LEC-III site. Finally an overview of PSM’s Combustion Technology Roadmap (CTR) will be discussed, which leverages their high-pressure, high-airflow test rig to evaluate technology improves with the objective of achieving guaranteed LEC-III combustion system NOx emissions below 3ppm NOx with low levels of CO.

scholarly journals Household COVID-19 risk and in-person schooling

Science ◽  
2021 ◽  
pp. eabh2939
Author(s):  
Justin Lessler ◽  
M. Kate Grabowski ◽  
Kyra H. Grantz ◽  
Elena Badillo-Goicoechea ◽  
C. Jessica E. Metcalf ◽  
...  
Keyword(s):  
United States ◽  
Online Survey ◽  
Positive Association ◽  
The United States ◽  
Mitigation Measures ◽  
Office Work ◽  
School Based ◽  
Increased Risk ◽  
Extra Curricular Activities ◽  
Low Levels

In-person schooling has proved contentious and difficult to study throughout the SARS-CoV-2 pandemic. Data from a massive online survey in the United States indicates an increased risk of COVID-19-related outcomes among respondents living with a child attending school in-person. School-based mitigation measures are associated with significant reductions in risk, particularly daily symptoms screens, teacher masking, and closure of extra-curricular activities. A positive association between in-person schooling and COVID-19 outcomes persists at low levels of mitigation, but when seven or more mitigation measures are reported, a significant relationship is no longer observed. Among teachers, working outside the home was associated with an increase in COVID-19-related outcomes, but this association is similar to other occupations (e.g., healthcare, office work). While in-person schooling is associated with household COVID-19 risk, this risk can likely be controlled with properly implemented school-based mitigation measures.

The United States Congress and Africanist Scholars

1991 ◽  
Vol 19 (2) ◽  
pp. 4-13
Author(s):  
David S. Wiley
Keyword(s):  
United States ◽  
Foreign Policy ◽  
The United States ◽  
African Studies ◽  
United States Congress ◽  
The Poor ◽  
Low Levels ◽  
The U.S

Linking scholars to the Congress is difficult primarily because of the weakness of Congressional interest in Africa, but also due to the low levels of interest among academics in both Congress and its Africa foreign policy and the poor resources of African studies in the U.S. to build a foundation of knowledge useful to the Congress.

The United States Navy “Standard Day” for Marine Gas Turbines

2017 ◽  
Author(s):  
John Hartranft ◽  
Bruce Thompson ◽  
Dan Groghan
Keyword(s):  
United States ◽  
Gas Turbine ◽  
United States Navy ◽  
Gas Turbines ◽  
The United States ◽  
Industrial Applications ◽  
Jet Engines ◽  
Jet Engine ◽  
Advantages And Disadvantages ◽  
Power Capability

Following the successful development of aircraft jet engines during World War II (WWII), the United States Navy began exploring the advantages of gas turbine engines for ship and boat propulsion. Early development soon focused on aircraft derivative (aero derivative) gas turbines for use in the United States Navy (USN) Fleet rather than engines developed specifically for marine and industrial applications due to poor results from a few of the early marine and industrial developments. Some of the new commercial jet engine powered aircraft that had emerged at the time were the Boeing 707 and the Douglas DC-8. It was from these early aircraft engine successes (both commercial and military) that engine cores such as the JT4-FT4 and others became available for USN ship and boat programs. The task of adapting the jet engine to the marine environment turned out to be a substantial task because USN ships were operated in a completely different environment than that of aircraft which caused different forms of turbine corrosion than that seen in aircraft jet engines. Furthermore, shipboard engines were expected to perform tens of thousands of hours before overhaul compared with a few thousand hours mean time between overhaul usually experienced in aircraft applications. To address the concerns of shipboard applications, standards were created for marine gas turbine shipboard qualification and installation. One of those standards was the development of a USN Standard Day for gas turbines. This paper addresses the topic of a Navy Standard Day as it relates to the introduction of marine gas turbines into the United States Navy Fleet and why it differs from other rating approaches. Lastly, this paper will address examples of issues encountered with early requirements and whether current requirements for the Navy Standard Day should be changed. Concerning other rating approaches, the paper will also address the issue of using an International Organization for Standardization, that is, an International Standard Day. It is important to address an ISO STD DAY because many original equipment manufacturers and commercial operators prefer to rate their aero derivative gas turbines based on an ISO STD DAY with no losses. The argument is that the ISO approach fully utilizes the power capability of the engine. This paper will discuss the advantages and disadvantages of the ISO STD DAY approach and how the USN STD DAY approach has benefitted the USN. For the future, with the advance of engine controllers and electronics, utilizing some of the features of an ISO STD DAY approach may be possible while maintaining the advantages of the USN STD DAY.

Identifying Current Driver Rehabilitation Practices for Clients With Physical Impairments

2021 ◽  
Vol 75 (Supplement_2) ◽  
pp. 7512515346p1-7512515346p1
Author(s):  
W. Ben Mortenson ◽  
Brittany Langereis ◽  
Sarah Semeniuk ◽  
Lisa Kristalovich
Keyword(s):  
United States ◽  
Clinical Guidelines ◽  
The United States ◽  
Physical Impairments ◽  
Levels Of Evidence ◽  
Low Levels ◽  
Primary Author

Abstract Date Presented Accepted for AOTA INSPIRE 2021 but unable to be presented due to online event limitations. Currently, there is a lack of clinical guidelines to support clinicians working in driver rehabilitation. This study aimed to identify intervention practices and factors that influence driver rehabilitation recommendations by surveying driver rehabilitation specialists practicing across the United States and Canada. Results revealed both consistencies and inconsistencies in practice, which may be related to jurisdictional differences and relatively low levels of evidence in this area. Primary Author and Speaker: W. Ben Mortenson Contributing Authors: Brittany Langereis, Sarah Semeniuk, and Lisa Kristalovich

Is Social Anxiety Making Us Depressed?: A Social Evolutionary Hypothesis for Why SSRIs Work

2008 ◽  
Vol 10 (1) ◽  
pp. 16-30 ◽  
Author(s):  
Laura K. Kerr
Keyword(s):  
Mental Health ◽  
United States ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Alternative Hypothesis ◽  
The United States ◽  
Global Competition ◽  
Low Levels ◽  
Chemical Imbalance ◽  
Developed Nations ◽  
Developed World

In the developed world, the use of selective serotonin reuptake inhibitors (SSRIs) has skyrocketed since 1988, when Prozac was first released in the United States. Biomedical psychiatry’s explanation for their success is an unsubstantiated hypothesis that claims SSRIs treat a chemical imbalance in people who suffer from low levels of the neurotransmitter serotonin. Using social evolutionary theory, this article provides an alternative hypothesis for why SSRIs work for some people. SSRIs’ success is attributed to their capacity to adapt people to the increased status anxiety occurring in developed nations grappling with the effects of unprecedented global competition. Biomedical psychiatry is depicted as adjusting patients to prevailing social norms rather than contributing to mental health.

FIELD PERFORMANCE OF ASIAN PEAR CULTIVARS IN THE HOT, HUMID SUMMER CONDITIONS OF THE MID-ATLANTIC REGION OF THE UNITED STATES

2015 ◽  
pp. 103-109
Author(s):  
C.S. Walsh ◽  
J.M. Harshman ◽  
A.E. Wallis ◽  
A.B. Williams ◽  
M.J. Newell ◽  
...  
Keyword(s):  
United States ◽  
Field Performance ◽  
The United States ◽  
Atlantic Region ◽  
Asian Pear

scholarly journals Safety and Immunogenicity of a Recombinant Nonglycosylated Erythrocyte Binding Antigen 175 Region II Malaria Vaccine in Healthy Adults Living in an Area Where Malaria Is Not Endemic

2010 ◽  
Vol 17 (10) ◽  
pp. 1552-1559 ◽  
Author(s):  
H. M. El Sahly ◽  
S. M. Patel ◽  
R. L. Atmar ◽  
T. A. Lanford ◽  
T. Dube ◽  
...  
Keyword(s):  
United States ◽  
Malaria Vaccine ◽  
Aluminum Phosphate ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Systemic Reactions ◽  
Erythrocyte Binding ◽  
Low Levels ◽  
Antibody Levels ◽  
Region Ii

ABSTRACT Erythrocyte binding antigen region II (EBA-175) is a conserved antigen of Plasmodium falciparum that is involved in binding of the parasite to the host's erythrocytes. We evaluated the safety and immunogenicity of a recombinant EBA-175 vaccine with aluminum phosphate adjuvant in healthy young adults living in the United States. Eighteen subjects/group received ascending doses (5, 20, 80, or 160 μg) of the vaccine at 0, 1, and 6 months; 8 subjects received placebo. Most of the injection site and systemic reactions were mild to moderate in intensity. After 2 or 3 doses of the vaccine at any concentration, antibody levels measured by enzyme-linked immunosorbent assay were significantly higher than those for the placebo group. Sera from subjects who received 3 doses of the vaccine at any concentration inhibited the growth of erythrocyte-stage P. falciparum at low levels compared to sera from placebo recipients or preimmune sera. In conclusion, the EBA-175 vaccine with adjuvant was safe and immunogenic in malaria-naïve subjects.

scholarly journals CAMPAIGN FINANCE IN COMPARATIVE PERSPECTIVE: A NESTED ANALYSIS APPROACH

2018 ◽  
Vol 2 (2) ◽  
pp. 225-250
Author(s):  
Ranulfo Paranhos ◽  
Dalson Filho ◽  
Enivaldo Rocha ◽  
José Alexandre Júnior
Keyword(s):  
United States ◽  
Campaign Finance ◽  
The United States ◽  
Campaign Contributions ◽  
Comparative Perspective ◽  
Low Levels ◽  
Standardized Measure ◽  
Nested Analysis ◽  
Nested Approach ◽  
Unites States

This paper analyzes campaign finance in a comparative perspective, giving special attention to Brazil and the Unites States. The focus regards the level of regulation on the sources of campaign contributions. Methodologically, the research design adopts a nested approach, combining descriptive and multivariate statistics with deep case studies and documental analysis. Additionally, we replicate data from the Institute for Democracy and Electoral Assistance (IDEA) to estimate a standardized measure of regulation. The results suggest that most countries show low levels of control over the sources of campaign contributions. However, both Brazil and the United States display high levels of regulation on campaign finance, despite their widely different institutional designs. 

scholarly journals Field Performance of Lettuce Grown in Alabama

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 600A-600
Author(s):  
Eric H. Simonne ◽  
Amarat H. Simonne ◽  
Larry W. Wells ◽  
Marvin E. Ruf ◽  
John T. Owen
Keyword(s):  
United States ◽  
Survival Rate ◽  
Drip Irrigation ◽  
Field Performance ◽  
The United States ◽  
Plastic Mulch ◽  
Potential Production ◽  
Postharvest Handling ◽  
Growing Conditions ◽  
Production Problems

While lettuce is one of the most widely consumed vegetables in the United States, production is mainly concentrated in the western states. This research investigated the feasibility of lettuce production in the Southeast (SE), where downy mildew, tip burn, bitterness, bolting, and postharvest handling are potential production problems. Lettuce varieties were evaluated on plastic mulch and drip irrigation under several growing conditions. Cultivar and location significantly (P < 0.01) affected yield and transplant survival rate. Following these tests, 'Salinas 88 Supreme', 'Legacy', 'Bullseye', 'Epic' (crisphead); 'Nancy', 'Nevada', 'Ostinata' (butterhead); 'Parris Islands', 'Augustus' (Romaine); and 'Red Salad Bowl', 'Red Prize', and 'Slobolt' (loose leaf) are considered best-performing lettuce varieties for Alabama. These results, along with bitterness evaluation, support the potential for lettuce production in the SE.

Sign in / Sign up

Export Citation Format

Share Document