Cement bond log (CBLTM) studies on foam-and synthetic-cemented wells were initiated to determine the feasibility of, as well as to develop technologies for, evaluating these novel cementing services. Early CBL's on these cementing systems showed little effect on the log amplitude curve. Hence, CBL evaluations were difficult to obtain and interpret.A special sonde with a 1.3-ft [O.4-m] transmitter-toreceiver spacing was developed for this study. Sonic signal amplitudes were determined by using cemented shortcasing test sections. Sonic attenuation rates were correlated to compressive strengths for a range of cement densities.Experimental details of the cementing operation and logging studies are discussed. Data relating attenuation rates to compressive strengths and cement densities also are presented. Field results are discussed.
Many studies have been conducted to describe and evaluate the benefits of freeway service patrols, but much less is known about the planning and institutional development of such programs. This case study describes the implementation of Tennessee’s freeway service patrols. In 1998 the Tennessee Department of Transportation (TDOT) began planning for patrols to operate on the highest-volume freeways in the state’s four largest cities—Chattanooga, Knoxville, Memphis, and Nashville. After a staged implementation plan, TDOT has successfully implemented the patrols, known as HELP, in all four cities while also moving forward with related intelligent transportation system and incident management initiatives. Five aspects of program development are described that have been especially important to the success of the program—teamwork, attention to human resource issues, comprehensive training, first-rate vehicles and equipment, and communications.
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The development lifecycle of software for aircraft systems is dominated by safety and cybersecurity considerations. Software development processes and tools are being continually updated to improve and optimize these critical considerations. While the processes and tools have received continuous updates, changes to the programming languages employed for developing safe and secure software for aircraft systems have evolved at a much slower pace. As of 2017, 63% of Department of Defense (DoD) systems were developed with the C/C++ programming languages (Ref. 1). This is representative of the dominant position that software developed with the C/C++ programming language has in existing aircraft avionics and mission systems. The C language has been around since the 1970s and C++ was first introduced in the late 1980s. These languages are very stable and their extensive supporting ecosystems have helped grow and maintain their expansive use in aerospace and many other domains. The longevity of C/C++ has enabled language, usage, process, and tool tailoring so that the software built with C/C++ can be certified for use in both safety-critical and security-critical environments. The C/C++ ecosystems are stable and mature but have properties that make writing software embedded in aircraft avionics very challenging.
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