Design curves for optimizing stability of herringbone-grooved journal bearings

Curves span wide range of operating conditions, including: lubricant compressibility numbers from 0 to 80, bearing length-to-diameter ratios from 1/4 to 2, and either rotating or stationary grooved members

When the back office moved to the front burner: settlement fails in the treasury market after 9/11

Settlement fails, which occur when securities are not delivered and paid for on the date scheduled by the buyer and seller, can expose market participants to the risk of loss due to counterparty insolvency. This article examines the institutional and economic setting of the fails problem that affected the Treasury market following September 11 and describes how the Federal Reserve and the U.S. Treasury responded. The authors explain that fails rose initially because of the physical destruction of trade records and communication facilities. Fails remained high because a relatively low federal funds rate and investor reluctance to lend securities kept the cost of borrowing securities to avert or remedy a fail comparable to the cost of continuing to fail. The fails problem was ultimately resolved when the Treasury increased the outstanding supply of the on-the-run ten-year note through an unprecedented "snap" reopening. The article also suggests other ways to alleviate chronic fails, such as the introduction of a securities lending facility run by the Treasury and the institution of a penalty fee for fails.Treasury bills ; Government securities ; War - Economic aspects

Optimization of self-acting herringbone-grooved journal bearings for maximum stability

Groove parameters were determined to maximize the stability of herringbone-grooved journal bearings. Parameters optimized were groove depth, width, length, and angle. Optimization was performed by using a small-eccentricity, infinite-groove analysis in conjunction with a previously developed Newton-Raphson procedure for bearings with the smooth member rotating or with the grooved member rotating at low compressibility numbers, and a newly developed vector technique for bearings with the grooved member rotating at high compressibility numbers. The design curves in this report enable one to choose the optimum bearing for a wide range of operating conditions. Compared with bearings optimized to maximize load capacity, bearings optimized for stability allow a thousandfold increase in bearing-supported mass in some cases before onset of instability, and lose no more than 77 percent of their load capacity in any case studied. Stability is much greater when the grooved member rotates

Plant microfossil record of the terminal Cretaceous event in the western United States and Canada

Plant microfossils, principally pollen grains and spores produced by land plants, provide an excellent record of the terminal Cretaceous event in nonmarine environments. The record indicates regional devastation of the latest Cretaceous vegetation with the extinction of many groups, followed by a recolonization of the earliest Tertiary land surface, and development of a permanently changed land flora. The regional variations in depositional environments, plant communities, and paleoclimates provide insight into the nature and effects of the event, which were short-lived but profound. The plant microfossil data support the hypothesis that an abruptly initiated, major ecological crisis occurred at the end of the Cretaceous. Disruption of the Late Cretaceous flora ultimately contributred to the rise of modern vegetation. The plant microfossils together with geochemical and mineralogical data are consistent with an extraterrestrial impact having been the cause of the terminal Cretaceous event

Optimization of self-acting herringbone journal bearing for maximum stability

Groove parameters were determined to maximize the stability of herringbone grooved journal bearings. Parameters optimized were groove depth, width, length, and angle. Optimization was performed using a small eccentricity, infinite groove analysis in conjunction with: (1) a previously developed Newton-Raphson procedure for bearings with the smooth member rotating or with the grooved member rotating at low compressibility numbers, and (2) a newly-developed vector technique for bearings with the grooved member rotating at high compressibility numbers. The design curves enable one to choose the optimum bearing for a wide range of operating conditions. These include: (1) compressibility numbers from 0 (incompressible) to 80, (2) length to diameter ratios from 1/4 to 2, and (3) smooth or grooved member rotating. Compared to bearings optimized to maximize load capacity, bearings optimized for stability: (1) allow a thousandfold increase in bearing-supported mass in some cases before onset of instability (the most dramatic increase are for bearings with small L/D operating at high compressibility numbers), and (2) lose no more than 77-percent of their load capacity in any case studied. Stability is much greater when the grooved member rotates

Repurchase agreements with negative interest rates

Contrary to popular belief, interest rates can drop below zero. From early August to mid-November of 2003, negative rates occurred on certain U.S. Treasury security repurchase agreements. An examination of the market conditions behind this development reveals why market participants are sometimes willing to pay interest on money lent.Repurchase agreements ; Interest rates ; Treasury notes

Explaining settlement fails

The Federal Reserve now makes available current and historical data on trades in U.S. Treasury and other securities that fail to settle as scheduled. An analysis of the data reveals substantial variation in the frequency of fails over the 1990-2004 period. It also suggests that surges in fails sometimes result from operational disruptions, but often reflect market participants' insufficient incentive to avoid failing.Government securities ; Electronic trading of securities

Shallow grooves in journal improve air bearing performance

Bearing designs, which shape the surface to create artificial fluid-film wedges in the absence of any applied radial load, generate radial restoring forces to keep journals from whirling. Helical- or herringbone-grooved journals or rotors show most promise of stable operation, with no sacrifice in load capacity

A Notable Experiment in Religious Education in India

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