Heavy Axle Load Effects on Fatigue Life of Steel Bridges

Author(s):  
John F. Unsworth

Heavy axle railway loads (freight equipment with more than a 100-ton capacity and gross vehicle weights exceeding 263,000 lb) have been introduced extensively on North American Class I freight railroads in the past decade. An overview is presented of the effects of heavy axle loads on the fatigue life of steel bridges in the North American freight railroad infrastructure. Also outlined are life extension and rehabilitation techniques typically used to maintain the safety and reliability of existing steel railway bridges.

2016 ◽  
Vol 31 (3) ◽  
pp. 438-457 ◽  
Author(s):  
Katie Kilroy-Marac

Within the past decade, material disorder—especially that of the domestic variety—has come to stand alternately as evidence, symptom, and potential cause of mental disorder in the North American popular and psychiatric imagination. Sources ranging from the newly defined Hoarding Disorder diagnosis in the DSM-V, to popular media, to agents of the burgeoning clutter-management industry describe disorder in terms of an irrational attachment, closeness, or overidentification with objects. At the same time, these sources imagine order to result from the cool distance and controlled passion a person is able to maintain toward his or her possessions. Drawing on more than twenty interviews and numerous fieldwork encounters with professional organizers (POs) in Toronto between 2014 and 2015, this article describes how POs aim to reorient their clients materially, morally, and affectively to relieve the disorder they report in their lives. Here, I argue, POs emerge as a species of late capitalist healer whose interventions are animated by a paradoxical double movement. For just as POs act to loosen the object attachments and disrupt the “secret sympathy” their clients share with their possessions, they operate within a realm of magical correspondence where matter and mind are imagined to reflect and affect one another, and where bringing order to a client’s possessions means also bringing order to his or her mind.


1995 ◽  
Vol 23 (1) ◽  
pp. 24-26
Author(s):  
William Martin ◽  
Michael West

Our thesis may be simply stated: There is a specter hanging over African studies: the specter of irrelevance both within and outside the academy. Indeed, African studies, as constructed in the North American academy over the past four decades, is dying.


2019 ◽  
Vol 113 ◽  
pp. 131-133
Author(s):  
Kirsten Nakjavani Bookmiller

It is a privilege to be with you today here at ASIL, in my current capacity as a Project Lead with the North American Humanitarian Response Initiative (NAHRI). At the heart of my comments today are essentially two main themes. First, all of our Initiative efforts over the past twenty-four months remain deeply intertwined with the ethic of Sendai and continue to be so. Second, while I hesitate to use the word “law” when I am working within the project—it can make those who are not in law a bit nervous—you will see with regard to NAHRI that the fundamental challenges that we have been attempting to work through are in fact legal challenges, and in the end I believe the solutions are also legally based. It is within this spirit that I will give my presentation.


Author(s):  
Robert R. Richwine ◽  
G. Scott Stallard ◽  
G. Michael Curley

In recent years some power companies have instituted programs aimed at reducing or eliminating their power plants’ unreliability caused by abnormal events that occur infrequently but result in extended unplanned outages when they do occur, i.e. High Impact–Low Probability events (HILPs). HILPs include catastrophic events such as turbine water induction, boiler explosions, generator winding failures, etc. Many of these successful programs have relied on the detailed reliability data contained in the North American Electric Reliability Corporation’s (NERC) Generating Availability Data System (GADS) that contains data collected over the past 25 years from 5000+ generating units in North America. Using this data, these companies have been able to 1) benchmark their fleet’s unreliability due to HILPs against their North American peers, 2) prioritize their peer group’s susceptibility to various HILP modes and 3) use root cause data contained within the NERC-GADS data base to help identify and evaluate ways to proactively prevent, detect and/or mitigate the consequences of HILP events. This paper will describe the methods used in these successful programs in sufficient detail to enable others to adopt the techniques for application at their own generating plants.


1990 ◽  
Vol 59 (4) ◽  
pp. 467-481
Author(s):  
Mark S. Burrows

Few issues have received as much attention and achieved as little consensus among historians of late medieval theology during the past several generations as the debate over the character of “nominalism.” One thrust of the research from this debate has focused on the theological dimensions of this scholastic tradition: building on the work of Erich Hochstetter, Paul Vignaux, and others, Heiko Oberman discussed this development in the North American arena of scholarship by describing theological concerns as “the inner core of nominalism.”1


Author(s):  
Fábio C. Barbosa

Abstract Shortline industry plays a prominent role in the North American Freight Rail System (mainly United States and Canada), providing a customized freight rail service to the shippers, i.e. the first/last mile rail access for those low dense/light demand markets, outside the Class I’s business model (highly loaded corridors), as well as competition enhancers, through the connection of shippers facilities with more than one Class I railroad. The Short Line’s Rail industry role and its inherent freight rail business model have been strengthened in the years that followed the so called Staggers Act (1980), in the U.S., in which freight rail carriers have focused their efforts on the high density rail markets. Meanwhile, the Shortlines, also known as Class II and Class III freight rail companies, have lead the way in the light density branch lines, providing a customized freight rail service to those shippers located outside the boundary limits of the rail trunk corridors. The importance of Shortline for the U.S. freight rail industry is illustrated by the 603 U.S. shortlines currently operating on 76,000 km (47,500 miles), providing service for one in five (20%) cars moving each year, which accounts for 29% of freight rail production in the country. Furthermore, the recent launch of the controversial Class I Precision Schedule Railroading (PSR) concept, and its inherent asset maximization (mainly associated with disruptive service features — essentially lane and yards closures), has strengthened the strategic importance of Shortlines in the U.S. freight rail scenario, which ultimately requires an improved Class I – Shortline relationship, to guarantee/maintain a connection between shippers (farmers, manufacturers and other industries), and the customers market. Brazil, a continental country located in South America, has a sprawled and low density rail network (28,218 km – 17,636.25 mi). Besides sprawled/low density, the Brazilian rail network is not uniformly demanded, with just 40% of the network with used (demanded) capacities higher than 50%, basically associated with iron ore and agricultural commodities transport (which accounts for almost 80% of the country’s whole freight rail production), while almost 60% of the network remain with very light use (available capacity higher than 80%). This picture shows a great opportunity for the introduction of the Shortline Rail Concept in the Brazilian Freight Rail System, focused on smaller rail operators to provide a customized and accessible freight rail service for shippers located in the influence area of the rail network. To reach this target, Brazil has basically two alternative pathways: i) a structural approach, associated with a complete network restructuration (in a similar way the U.S. Class I railroads have marketed unproductive branches to short line operators) and ii) a regulatory approach, in which the current concession format would be maintained, with the imposition of rail stretches production targets to current rail concessionaires (incumbents), which ultimately could be encouraged to set operational partnerships with the so called Independent Rail Operators (IRO), to comply with those production rail targets. This work is supposed to present an overview, in a review format, of the North American Shortline Freight Rail experience, highlighting its operational regime/requirements, the business model, the tax incentives and the Shortline’s role in the class I PSR scenario. This analysis is, then, followed by an assessment of the perspectives and the inherent pathways for a Shortline Freight Rail Model implementation in Brazil.


1999 ◽  
Vol 47 (3) ◽  
pp. 445 ◽  
Author(s):  
Henry Mann ◽  
Vernon W. Proctor ◽  
Alberto S. Taylor

The great bulk of the world’s charophyte literature of the past 100 years or more suffers from several major limitations. Much is entirely descriptive with but few attempts to ascribe any functionality to the features under consideration, or how they adapt such species to their respective ecological niches. Charophyte distributions have been attributed almost entirely to physical parameters with virtually no consideration given to the role of aquatic herbivores or other biotic environmental factors. Furthermore, most workers have focused on relatively restricted areas with little or no reference to others either near or far removed. That there is much to be gained from a wider focus (both spatially and conceptually) that incorporates greater conjecture as well as enhanced collaboration is here suggested. How are the charophyte floras of one region similar to, or different from, those of another, and, of particular significance, ‘Why?’ The authors, being North American, focus on that continent but with the firm conviction that most generalities applicable there hold equally true for other landmasses, and have done so for the previous 10, if not 100, million years. This account focuses first, if somewhat superficially, on 14 widely distinct North American charophyte communities (plus South American Lake Titicaca) and then in greater detail on four of those. Among other issues considered are how species richness relates to latitude; why some geographical entities support more charophyte species than do others; the extent to which charophyte floras reflect the availability of different habitats; the contributions of herbivory to the preceding; the stability of the North American charophyte flora; the ecological considerations most often reflected by charophyte zonation and how–or to what extent–range extensions reflect niche preferences or requirements. While the authors well appreciate just how minimal their efforts may appear a century hence, at least they hope to have placed on the table some considerations with which colleagues from other landmasses may agree, disagree or suggest modifications.


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