The Civil Aeronautics Board (CAB) was an agency of the federal government of the United States, formed in 1938 and abolished in 1985, that regulated aviation services including scheduled passenger airline service and provided air accident investigation. The agency headquarters were in Washington, D.C.C.
Service failures have occurred in a number of aircraft parts made of quenched and tempered steel heat treated to ultimate tensile strengths of 260,000–280,000 psi. Some of these failures have been attributed to “delayed cracking” as a result of hydrogen embrittlement or to stress-corrosion. Because of the serious nature of the failures and because the mechanism of the fracture initiation is not well understood, unusually complete laboratory investigations have been conducted. Three of these investigations are reviewed to illustrate the methods used in studying failures in aircraft parts. The results of the laboratory studies indicate that unusual care is necessary in the processing and fabrication of ultra-high-strength steel and in the design and maintenance of the structures in which it is used.
Within the methodological process carried out in the reconstruction of traffic accidents, it is necessary to determine the coefficients of deceleration or friction to be used, depending on the case, to objectively establish the traffic speeds of the vehicles involved, taking into account: the type of vehicle, surface and geometry of the roadway and its condition; To this end, researchers in the field have carried out experiments since the 1970s in order to establish these coefficients for various situations. The most commonly used methods take up the statistical analysis of data obtained through measurements made in the field, technological tools such as digital accelerometers or images processed with video cameras. The purpose of this work was to demonstrate that the accuracy of the data obtained from the video images taken by a DJI Mavic Pro Unmanned Aerial Vehicle and processed in Tracker (R) educational software can be compared with the information recorded with a VC4000 digital accelerometer, being The first solution is an option with a rationally lower cost, with a rate of obtaining information that is higher than the second, and with a versatility to execute scenarios that is notoriously superior.
TRADITIONAL ECONOMIC ANALYSIS of the theory of the firm has concentrated on single-product firms. But, in reality, most businesses produce many products, and many regulatory and antitrust issues involve only these enterprises. In recent years, economists and policymakers dealing with antitrust and regulatory issues have increasingly recognized the need for a theory that can be used to evaluate the efficiency of market structures in industries dominated by a few firms operating in a diverse range of markets. For such firms, conventional concepts of structure and performance such as economies of scale, measures of concentration, and barriers to entry do not adequately capture the complexity of market relationships. A few examples illustrate the complexities introduced by the multi-product firm and highlight the need for a theory that can be used to evaluate performance and conduct in its markets. In many trucking and air city-pair markets, the efficient number of carriers appears to be relatively small (perhaps even one). Does this imply, however, that trucking firms and air carriers that compete in a wide range of city-pair markets should be regulated as natural monopolists or that mergers involving overlapping markets should be disallowed? In the petroleum industry, there is a current trend to diversify into other sources of fuel, and in cable TV markets there are numerous attempts to integrate vertically. What should economists look for in evaluating whether these changes in market structure are motivated by efficiency or by anticompetitive behavior? For a dominant firm, such as AT&T, there is a frequent complaint that the incumbent firm is preventing entry by cross-subsidizing one of its products, which faces competition by entrants, at the expense of other of its products. What kinds of regulatory intervention in pricing or in market structure must be considered
