Comparison of experimental and predicted performance of 150-millimeter-bore solid and drilled ball bearings to 3 million DN

Seven 150-millimeter-bore ball bearings were run under 8900-newton (2000-lbf) thrust load at speeds from 6670 to 20,000 rpm (1 million to 3 million DN). Four of the bearings had conventional solid balls, and three bearings had drilled (cylindrically hollow) balls with 50-percent mass reduction. The bearings were under-race cooled and slot lubricated with a type 2 ester oil at flow rates from 4.35 x 0.001 to 5.94 x 0.001 cubic meter/min (1.15 to 1.57 gal/min). Friction torque and temperature were measured on all bearings. While there was considerable spread in the temperature data, the drilled ball bearings tended to run slightly cooler than the solid ball bearings at higher speeds. No significant difference in torque was noted, however, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800-newton (4000-lbf) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball, and cracks appeared in other balls as a result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls

Chronic Tetanus in a Horse

On June 12, 1941, I was called to see a horse which the owner thought had tetanus

Comparative Study of Activities Preferred by Elementary Pupils vs. Teacher-Directed Activities

It was the purpose of this study (1) to determine the activities elementary school students prefer to do while they are attending school; (2) to determine the activities that are now being used by teachers; and (3) to compare the activities preferred by students with those used by teachers

Legacy of Lost Opportunity: Designated Entities and the Federal Communications Commission\u27s Broadband PCS Spectrum Auction, A

The Federal Communications Commission\u27s ( FCC ) designated entity policy has challenged the efficiency of the use of auctions to allocate spectrum licenses. As an alternative to comparative hearings and lotteries, auctions provide an effective solution to the costs, administrative burdens, and delays associated with apportioning spectrum. Congress required the FCC to allow firms to participate in the auctions even if they had difficulty in obtaining financing. The FCC gave these firms, known as designated entities, set-asides and other preferences to assist them in the competitive bidding process. In the broadband Personal Communications Services ( PCS ) auctions, however, designated entities frequently were unable to pay for their winning bids. Some of these firms took advantage of programs offered by the FCC to help pay for their licenses, while others surrendered their licenses to the Commission. Several firms also sought protection from the courts, which resulted in litigation costs and delays. Most importantly, some licenses sat dormant while these companies struggled to finance their bids, preventing customers from benefiting from their use. These factors combined to undermine the effectiveness of the auction process. Commissioner Harold Furchtgott-Roth claims the government\u27s designated entity policies doomed these licenses to failure, calling these blocks of licenses set aside for designated entities a legacy of lost opportunity. This article begins by explaining the history of FCC licensing authority in Part I. Next, Part II reviews the FCC\u27s implementation of auction procedures and policies, including those for designated entities. Part III discusses some of the problems encountered by bidders who failed to pay for their winning bids at auctions, most notably NextWave. Part IV examines attempts by the government and industry to resolve the difficulties faced by these bidders. Lastly, Part V analyzes the FCC\u27s ultimate decision to cancel NextWave\u27s licenses and to include them in a reauction

Legacy of Lost Opportunity: Designated Entities and the Federal Communications Commission\u27s Broadband PCS Spectrum Auction, A

The Federal Communications Commission\u27s ( FCC ) designated entity policy has challenged the efficiency of the use of auctions to allocate spectrum licenses. As an alternative to comparative hearings and lotteries, auctions provide an effective solution to the costs, administrative burdens, and delays associated with apportioning spectrum. Congress required the FCC to allow firms to participate in the auctions even if they had difficulty in obtaining financing. The FCC gave these firms, known as designated entities, set-asides and other preferences to assist them in the competitive bidding process. In the broadband Personal Communications Services ( PCS ) auctions, however, designated entities frequently were unable to pay for their winning bids. Some of these firms took advantage of programs offered by the FCC to help pay for their licenses, while others surrendered their licenses to the Commission. Several firms also sought protection from the courts, which resulted in litigation costs and delays. Most importantly, some licenses sat dormant while these companies struggled to finance their bids, preventing customers from benefiting from their use. These factors combined to undermine the effectiveness of the auction process. Commissioner Harold Furchtgott-Roth claims the government\u27s designated entity policies doomed these licenses to failure, calling these blocks of licenses set aside for designated entities a legacy of lost opportunity. This article begins by explaining the history of FCC licensing authority in Part I. Next, Part II reviews the FCC\u27s implementation of auction procedures and policies, including those for designated entities. Part III discusses some of the problems encountered by bidders who failed to pay for their winning bids at auctions, most notably NextWave. Part IV examines attempts by the government and industry to resolve the difficulties faced by these bidders. Lastly, Part V analyzes the FCC\u27s ultimate decision to cancel NextWave\u27s licenses and to include them in a reauction

Legacy of Lost Opportunity: Designated Entities and the Federal Communications Commission\u27s Broadband PCS Spectrum Auction, A

The Federal Communications Commission\u27s ( FCC ) designated entity policy has challenged the efficiency of the use of auctions to allocate spectrum licenses. As an alternative to comparative hearings and lotteries, auctions provide an effective solution to the costs, administrative burdens, and delays associated with apportioning spectrum. Congress required the FCC to allow firms to participate in the auctions even if they had difficulty in obtaining financing. The FCC gave these firms, known as designated entities, set-asides and other preferences to assist them in the competitive bidding process. In the broadband Personal Communications Services ( PCS ) auctions, however, designated entities frequently were unable to pay for their winning bids. Some of these firms took advantage of programs offered by the FCC to help pay for their licenses, while others surrendered their licenses to the Commission. Several firms also sought protection from the courts, which resulted in litigation costs and delays. Most importantly, some licenses sat dormant while these companies struggled to finance their bids, preventing customers from benefiting from their use. These factors combined to undermine the effectiveness of the auction process. Commissioner Harold Furchtgott-Roth claims the government\u27s designated entity policies doomed these licenses to failure, calling these blocks of licenses set aside for designated entities a legacy of lost opportunity. This article begins by explaining the history of FCC licensing authority in Part I. Next, Part II reviews the FCC\u27s implementation of auction procedures and policies, including those for designated entities. Part III discusses some of the problems encountered by bidders who failed to pay for their winning bids at auctions, most notably NextWave. Part IV examines attempts by the government and industry to resolve the difficulties faced by these bidders. Lastly, Part V analyzes the FCC\u27s ultimate decision to cancel NextWave\u27s licenses and to include them in a reauction

COMET: A Recipe for Learning and Using Large Ensembles on Massive Data

COMET is a single-pass MapReduce algorithm for learning on large-scale data. It builds multiple random forest ensembles on distributed blocks of data and merges them into a mega-ensemble. This approach is appropriate when learning from massive-scale data that is too large to fit on a single machine. To get the best accuracy, IVoting should be used instead of bagging to generate the training subset for each decision tree in the random forest. Experiments with two large datasets (5GB and 50GB compressed) show that COMET compares favorably (in both accuracy and training time) to learning on a subsample of data using a serial algorithm. Finally, we propose a new Gaussian approach for lazy ensemble evaluation which dynamically decides how many ensemble members to evaluate per data point; this can reduce evaluation cost by 100X or more