Removals for Cause: A 35-Year Assessment of LM2500 Engine Removals by the United States Navy

Author(s):  
Matthew J. Driscoll ◽  
Eric M. McFetridge ◽  
Jeffrey S. Patterson ◽  
Craig A. See

The United States (US) Navy has operated the General Electric LM2500 gas turbine on all its surface combatants for the past 35 years. The LM2500 is utilized as the propulsion engine aboard the US Navy’s newest surface combatants including the FFG 7, CG 47 and DDG 51 Class ships. The US Navy owns and operates 400 LM2500 engines. An on-condition maintenance philosophy is employed whereby engines are run-to-failure rather than removed from service upon achieving some operating milestone. This paper assesses the reasons for the removal of the US Navy’s LM2500s over their entire service life with a focus on how fleet maintenance capabilities have impacted and affected the cause for engine replacements over time.

Author(s):  
John S. Siemietkowski ◽  
Walter S. Williams

The General Electric LM2500 Marine Gas Turbine, currently used by the United States Navy as main propulsion on various classes of ships, lends itself very easily to a procedure known as photoborescopy. Photoborescopy is that process where discrete, color photographs are taken of various internal parts of the engine. Borescoping in itself is not new, but maximizing the borescopes capabilities is a program that the U.S. Navy continuously is developing at the Naval Ship Systems Engineering Station (NAVSSES) in Philadelphia, Pennsylvania. This paper will describe the photoborescopy technique used by NAVSSES and also give and show graphically the Fleet experience with two LM2500’s which had accumulated 10,000 hours of successful at-sea operation. The opinions expressed herein are those of the author and not necessarily of the Department of Defense or the Navy Department.


2018 ◽  
Vol 53 (2) ◽  
pp. 346-370 ◽  
Author(s):  
Andrew Kennedy

The United States has long been a magnet for skilled immigrants, but its openness to these immigrants has varied considerably over time. Focusing on the H-1B visa program, this article explains why the program’s annual cap has risen and fallen from the mid-1990s to the present. Whereas recent studies of skilled immigration policy have focused on struggles between capital and labor, this article contends that US policy also reflects a struggle between capital and citizen groups — one that has changed considerably over the past two decades. The findings challenge recent work on skilled immigration and US immigration policy.


2008 ◽  
Vol 51 (4) ◽  
pp. 1047-1067 ◽  
Author(s):  
R. KIM CRAGIN

ABSTRACTAlthough the broad outlines of al-Qa'ida's story are well known, less attention has been paid to its early development and evolution. How and why did al-Qa'ida leaders latch on to the United States as a primary adversary? What motivated Usama bin Laden to form al-Qa'ida in the first place? Did this motivation change over time? This article utilizes a series of recently discovered al-Qa'ida documents – such as al-Jihad magazine financed by Usama bin Laden during the 1980s, internal memos written in the early 1990s and captured by the US military in Afghanistan, and autobiographical accounts written since 2001 by former Afghan Arab fighters – to deepen our understanding of a clandestine organization that has caused havoc for the past two decades.


2009 ◽  
Vol 1 (1) ◽  
pp. 93-116 ◽  
Author(s):  
Mauricio Tenorio-Trillo

By identifying two general issues in recent history textbook controversies worldwide (oblivion and inclusion), this article examines understandings of the United States in Mexico's history textbooks (especially those of 1992) as a means to test the limits of historical imagining between U. S. and Mexican historiographies. Drawing lessons from recent European and Indian historiographical debates, the article argues that many of the historical clashes between the nationalist historiographies of Mexico and the United States could be taught as series of unsolved enigmas, ironies, and contradictions in the midst of a central enigma: the persistence of two nationalist historiographies incapable of contemplating their common ground. The article maintains that lo mexicano has been a constant part of the past and present of the US, and lo gringo an intrinsic component of Mexico's history. The di erences in their historical tracks have been made into monumental ontological oppositions, which are in fact two tracks—often overlapping—of the same and shared con ictual and complex experience.


2021 ◽  
Author(s):  
Jeffrey S. Patterson ◽  
Kevin Fauvell ◽  
Dennis Russom ◽  
Willie A. Durosseau ◽  
Phyllis Petronello ◽  
...  

Abstract The United States Navy (USN) 501-K Series Radiological Controls (RADCON) Program was launched in late 2011, in response to the extensive damage caused by participation in Operation Tomodachi. The purpose of this operation was to provide humanitarian relief aid to Japan following a 9.0 magnitude earthquake that struck 231 miles northeast of Tokyo, on the afternoon of March 11, 2011. The earthquake caused a tsunami with 30 foot waves that damaged several nuclear reactors in the area. It was the fourth largest earthquake on record (since 1900) and the largest to hit Japan. On March 12, 2011, the United States Government launched Operation Tomodachi. In all, a total of 24,000 troops, 189 aircraft, 24 naval ships, supported this relief effort, at a cost in excess of $90.0 million. The U.S. Navy provided material support, personnel movement, search and rescue missions and damage surveys. During the operation, 11 gas turbine powered U.S. warships operated within the radioactive plume. As a result, numerous gas turbine engines ingested radiological contaminants and needed to be decontaminated, cleaned, repaired and returned to the Fleet. During the past eight years, the USN has been very proactive and vigilant with their RADCON efforts, and as of the end of calendar year 2019, have successfully completed the 501-K Series portion of the RADCON program. This paper will update an earlier ASME paper that was written on this subject (GT2015-42057) and will summarize the U.S. Navy’s 501-K Series RADCON effort. Included in this discussion will be a summary of the background of Operation Tomodachi, including a discussion of the affected hulls and related gas turbine equipment. In addition, a discussion of the radiological contamination caused by the disaster will be covered and the resultant effect to and the response by the Marine Gas Turbine Program. Furthermore, the authors will discuss what the USN did to remediate the RADCON situation, what means were employed to select a vendor and to set up a RADCON cleaning facility in the United States. And finally, the authors will discuss the dispensation of the 501-K Series RADCON assets that were not returned to service, which include the 501-K17 gas turbine engine, as well as the 250-KS4 gas turbine engine starter. The paper will conclude with a discussion of the results and lessons learned of the program and discuss how the USN was able to process all of their 501-K34 RADCON affected gas turbine engines and return them back to the Fleet in a timely manner.


Author(s):  
Matthew Driscoll ◽  
Thomas Habib ◽  
William Arseneau

The United States Navy uses the General Electric LM2500 gas turbine engine for main propulsion on its newest surface combatants including the OLIVER HAZARD PERRY (FFG 7) class frigates, SPRUANCE (DD 963) class destroyers, TICONDEROGA (CG 47) class cruisers, ARLIEGH BURKE (DDG 51) class destroyers and SUPPLY (AOE 6) class oilers. Currently, the Navy operates a fleet of over 400 LM2500 gas turbine engines. This paper discusses the ongoing efforts to characterize the availability of the engines aboard ship and pinpoint systems/components that have significant impact on engine reliability. In addition, the program plan to upgrade the LM2500’s standard configuration to improve reliability is delineated.


Author(s):  
John Hartranft ◽  
Bruce Thompson ◽  
Dan Groghan

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.


Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 659-666 ◽  
Author(s):  
Amanda Saville ◽  
Kim Graham ◽  
Niklaus J. Grünwald ◽  
Kevin Myers ◽  
William E. Fry ◽  
...  

Phytophthora infestans causes potato late blight, an important and costly disease of potato and tomato crops. Seven clonal lineages of P. infestans identified recently in the United States were tested for baseline sensitivity to six oomycete-targeted fungicides. A subset of the dominant lineages (n = 45) collected between 2004 and 2012 was tested in vitro on media amended with a range of concentrations of either azoxystrobin, cyazofamid, cymoxanil, fluopicolide, mandipropamid, or mefenoxam. Dose-response curves and values for the effective concentration at which 50% of growth was suppressed were calculated for each isolate. The US-8 and US-11 clonal lineages were insensitive to mefenoxam while the US-20, US-21, US-22, US-23, and US-24 clonal lineages were sensitive to mefenoxam. Insensitivity to azoxystrobin, cyazofamid, cymoxanil, fluopicolide, or mandipropamid was not detected within any lineage. Thus, current U.S. populations of P. infestans remained sensitive to mefenoxam during the displacement of the US-22 lineage by US-23 over the past 5 years.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Fadar Otite ◽  
Smit Patel ◽  
Richa Sharma ◽  
Pushti Khandwala ◽  
Devashish Desai ◽  
...  

Background: The primary aim of this study is to describe current trends in racial-, age- and sex-specific incidence, clinical characteristics and burden of cerebral venous thrombosis (CVT) in the United States (US). Methods: Validated International Classification of Disease codes were used to identify all adult new cases of CVT (n=5,567) in the State Inpatients Database of New York and Florida (2006-2016) and all cases of CVT in the entire US from the National Inpatient Sample 2005-2016 (weighted n=57,315). Incident CVT counts were combined with annual US Census data to compute age and sex-specific incidence of CVT. Joinpoint regression was used to evaluate trends in incidence over time. Results: From 2005-2016, 0.47%-0.80% of all strokes in the US were CVTs but this proportion increased by 70.4% over time. Of all CVTs over this period, 66.7% were in females but this proportion declined over time (p<0.001). Pregnancy/puerperium (27.4%) and cancer (11.8%) were the most common risk factors in women, while cancer (19.5%) and central nervous trauma (11.3) were the most common in men. Whereas the prevalence of pregnancy/puerperium declined significantly over time in women, that of cancer, inflammatory conditions and trauma increased over time in both sexes. Annual age and sex-standardized incidence of CVT in cases/million population ranged from 13.9-20.2, but incidence varied significantly by sex (women: 20.3-26.9; men 6.8-16.8) and by age/sex (women 18-44yo: 24.0-32.6%; men: 18-44yo: 5.3-12.8). Age and sex-standardized incidence also differed by race (Blacks:18.6-27.2; whites: 14.3-18.5; Asians: 5.1-13.8). On joinpoint regression, incidence increased across 2006-2016 but most of this increase was driven by increase in all age groups of men (combined annualized percentage change (APC) 9.2%, p-value <0.001), women 45-64 yo (APC 7.8%, p-value <0.001) and women ≥65 yo (APC 7.4%, p-value <0.001). Incidence in women 18-44 yo remained unchanged over time . Conclusion: The epidemiological characteristics of CVT patients in the US is changing. Incidence increased significantly over the last decade. Further studies are needed to determine whether this increase represents a true increase from changing risk factors or artefactual increase from improved detection.


Author(s):  
Thomas Steinfatt ◽  
Dana Janbek

This chapter focuses on the use of propaganda during times of war, prejudice, and political unrest. Part one distinguishes between persuasion and one of its forms, propaganda. The meaning-in-use of the term ‘propaganda' is essential to understanding its use over time. Part two presents relevant examples of propaganda from the past several centuries in the United States and Europe. These examples include episodes from World War I and II, among others. Propaganda is not a new tool of persuasion, and learning about its use in the past provides a comparison that helps in understanding its use in the present and future. Part three looks at recent examples of how propaganda occurs in actual use in online terrorist mediums by Al-Qaeda and by the Islamic State in Iraq and Syria (ISIS).


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