Evaluation of strength characteristics of recycled asphalt pavement materials

Use of recycled asphalt pavement (RAP) can reduce the cost of pavement materials significantly. In Queensland, the Department of Transport and Main Roads is reluctant to increase RAP usages and has placed stricter limits, allowing a maximum RAP content of only 15% by mass of mix. This is due to the fact that the presence of aged and stiffer binder can increase the resilient modulus of the mixtures and reduce fatigue life if no allowance is made. Researchers' suggest adapting a low grade binder as an option when using higher percentage of RAP. This research was to assess whether using a softer binder could help to improve the fatigue life of high percentile RAP mixtures. The mix design tested was a dense grade 20mm base course. Experiments were carried out to find the mechanical properties of batches comprised of 0, 15% RAP with same binder and 30%, 45% and 60% of RAP with one step lower level binder. During batching all possible efforts were taken to maintain homogeneity between the samples, and effective binder volume was adjusted for air voids before estimating the actual modulus. The results were used to estimate the fatigue life using the Austroads' fatigue model. It was found that mixing higher percentile RAP together with the binder one grade lower than usual can be effective in reducing residual modulus and improving fatigue life of the pavement. However, there is also potential to overcompensate, yielding softer mixes which may be more susceptible to rutting. It was also found that 60% mix could give similar mechanical performance to a conventional mix. In summary, using the softer binder had the greatest impact on blended binder fatigue life so Australian guidelines can be improved to make the most effective use of recycled asphalts where further studies are required

Defining the Proper Scope of Internet Patents: If We Don\u27t Know Where We Want to go, We\u27re Unlikely to get There

Part I of this Article addresses the appropriateness of protecting Internet innovations under the current patent regime. It concludes that the doctrinal, historical and policy arguments require different outcomes regarding computing (patentable subject matter) and competitive arts (at best a difficult fit) innovation. Part II argues that the new electronic economy has given rise to a particular kind of competitive arts market failure (interference with first-to-move lead-time incentives) which must be addressed. It concludes, however, that tinkering with the existing patent or copyright regimes is not only complex, but poses significant risks, and should be avoided. Part III sketches the outlines of a proposed competitive arts regime, combining the qualification features of patent law with the more nuanced approach to rights and remedies of copyright law. Part IV concludes by outlining a number of interim measures necessary to mitigate the effects of protecting the competitive arts under traditional patent law while awaiting the arrival of the new regime

Augmenting CCAM Infrastructure for Creating Smart Roads and Enabling Autonomous Driving

Autonomous vehicles and smart roads are not new concepts and the undergoing development to empower the vehicles for higher levels of automation has achieved initial milestones. However, the transportation industry and relevant research communities still require making considerable efforts to create smart and intelligent roads for autonomous driving. To achieve the results of such efforts, the CCAM infrastructure is a game changer and plays a key role in achieving higher levels of autonomous driving. In this paper, we present a smart infrastructure and autonomous driving capabilities enhanced by CCAM infrastructure. Meaning thereby, we lay down the technical requirements of the CCAM infrastructure: identify the right set of the sensory infrastructure, their interfacing, integration platform, and necessary communication interfaces to be interconnected with upstream and downstream solution components. Then, we parameterize the road and network infrastructures (and automated vehicles) to be advanced and evaluated during the research work, under the very distinct scenarios and conditions. For validation, we demonstrate the machine learning algorithms in mobility applications such as traffic flow and mobile communication demands. Consequently, we train multiple linear regression models and achieve accuracy of over 94% for predicting aforementioned demands on a daily basis. This research therefore equips the readers with relevant technical information required for enhancing CCAM infrastructure. It also encourages and guides the relevant research communities to implement the CCAM infrastructure towards creating smart and intelligent roads for autonomous driving

NASA Tech Briefs, June 1993

Topics include: Imaging Technology: Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

American Society for Engineering Education/NASA Summer Faculty Fellowship Program 1982

A program of summer faculty fellowships for engineering and science educators is described. The program involves participation in cooperative research and study. Results of the program evaluation are summarized. The research fellows indicated satisfaction with the program. Benefits of the program cited include: (1) enhancement of professional abilities; (2) contact with professionals in a chosen area of research; (3) familiarity with research facilities; and (4) development of new research techniques and their adaptation to an academic setting. Abstracts of each of the research projects undertaken are presented

An investigation of transitional management problems for the NSTS

Analysis and recommendations were provided to the National Space Transportation System (NSTS) on managing the transition from a research and development (R/D) structure to an operational structure. Summaries of published literature on the theory and applications of transition, or change management, and the results of interviews with additional industry personnel whose organizations either have gone through or are now going through change are contained. The issues of flight rates and the flight decision are addressed. The use of a computer simulation model to analyze the effect of varying different parameters on the flight rate was also discussed. The issue of NASA's changing demographics was examined and why this may be a cause for concern. The impact of the whole shuttle system structure on the Challenger accident was presented along with the highlights of the Rogers Commission Report. The proposed reorganization of the NSTS management structure is discussed and how this transition from R/D to operations can be performed

‘Rationality’ in Collective Escape Behaviour: Identifying Reference Points of Measurement at Micro and Macro Levels

italic"Background"/jats:italic". Evacuation behaviour of human crowds is often characterised by the notion of ‘irrational behaviour’. While the term has been frequently used in the literature, clear definitions and methods for measuring rationality do not exist."jats:italic" Objective"/jats:italic". Here, we suggest that rationality, in this context, can alternatively and more effectively be formulated as a question of ‘optimal behaviour’. Decision optimality can potentially be measured and quantified. The main challenges, however, include (i) distinctly identifying the level at which we measure optimality, and (ii) identifying proper reference points at each level."jats:italic" Methods"/jats:italic". We differentiate between optimality at the individual (i.e., micro) and the system (i.e., macro/aggregate) levels and illustrate how certain reference points can be established at each level. We suggest that, at the micro level, optimality of individual decisions can be quantified by comparing the outcome of each individual’s decision to those of their ‘nearly equal peers’. At the macro level, optimality can be measured by simulating the system using parametric numerical models and measuring the system performance while altering the behavioural parameters compared to their empirical estimates."jats:italic" Results"/jats:italic". Having applied these methods, we observed that variation in micro level decision optimality rises rapidly as the space becomes more heavily crowded. As crowdedness increases in the environment, the difference between ‘good’ and ‘bad’ decisions becomes more distinct; and suboptimal decisions become more frequent. In other words, optimality at individual level seems to be moderated by the level of crowdedness. At the macro level, numerical simulations showed that, for certain exit attributes (like exit congestion), extreme marginal valuations (or preferences) were optimal, whereas for certain other attributes (like exit visibility), intermediate levels of valuation were closer to the optimal. In most cases, the natural observed (or estimated) tendency of evacuees (at the aggregate level) was not quite at the optimum level, meaning that the system could improve by modifying individuals’ marginal valuations of exit attributes."jats:italic" Applications and Recommendations"/jats:italic". These results highlight the importance of guiding evacuation decisions particularly in heavily crowded spaces. They also theoretically illustrate the potential benefit of influencing/modifying people’s evacuation strategies, so they make decisions that are collectively more efficient. A crucial step to this end, however, is to identify what optimum strategy is and under what circumstances people are likelier to make suboptimal decisions. Document type: Articl

Work Zone Safety Analysis, Investigating Benefits from Accelerated Bridge Construction (ABC) on Roadway Safety

The attributes of work zones have significant impacts on the risk of crash occurrence. Therefore, identifying the factors associated with crash severity and frequency in work zone locations is of important value to roadway safety. In addition, the significant loss of workers’ lives and injuries resulting from work zone crashes indicates the emergent need for a comprehensive and in-depth investigation of work zone crash mechanisms. The cost of work zone crashes is another issue that should be taken into account as work zone crashes impose millions of dollars on society each year. Applying innovative construction methods like Accelerated Bridge Construction (ABC) dramatically decreases on-site construction duration and thus improves roadway safety. This safe and cost-effective procedure for building new bridges or replacing/rehabilitating existing bridges in just a few weeks instead of months or years may prevent crashes and avoid injuries as a result of work zone presence. The application of machine learning techniques in traffic safety studies has seen explosive growth in recent years. Compared to statistical methods, MLs are more accurate prediction models due to their ability to deal with more complex functions. To this end, this study focuses on three major areas: crash severity at construction work zones with worker presence, crash frequency at bridge locations, and assessment of the associated costs to calculate the contribution of safety to the benefit-cost ratio of ABC as compared to conventional methods. Some key findings of this study can be highlighted as in-depth investigation of contributing factors in conjunction with the results from statistical and machine learning models, which can provide a more comprehensive interpretation of crash severity/frequency outcomes. The demonstration of work zone crashes needs to be modeled separately by time of day for severity analysis with a high level of confidence. Investigation of the contributing factors revealed the nonlinear relationship between crash severity/frequency and contributing factors. Finally, the results showed that the safety benefits from a case study in Florida consisted of 43% of the total ABC implementation cost. This indicates that the safety benefits of ABC implementation consist of a considerable portion of its benefit-cost ratio

Law\u27s Signal: A Cueing Theory of Law in Market Transition

Securities markets are commonly assumed to spring forth at the intersection of an adequate supply of, and a healthy demand for, investment capital. In recent years, however, seemingly failed market transitions - the failure of new markets to emerge and of existing markets to evolve - have called this assumption into question. From the developed economies of Germany and Japan to the developing countries of central and eastern Europe, securities markets have exhibited some inability to take root. The failure of U.S. securities markets, and particularly the New York Stock Exchange, to make greater use of computerized trading, communications, and processing technologies, meanwhile, seems to suggest market resistance to technological modernization. In light of this pattern, one must wonder: How are strong markets created and maintained, and what might be law\u27s role in this process?This Article attempts to articulate a model for understanding the needs of efficient market transition and the resulting role of law in that process. Specifically, it suggests a cueing function for law in market transition. Grounded in largely ignored lessons of game theory and microeconomic analysis of so-called network effects, cueing theory identifies the coordination of market participants\u27 expectations as law\u27s central role in market transition. Building on recent legal literature on private regulation, social norms, and the expressive function of law, this theory suggests that in securities market transition - whether it be market creation in central and eastern Europe or market restructuring in the United States - law primarily serves to convene, encourage, inform, and facilitate.A cueing role for law constitutes an important extension of traditional conceptions of what law does, particularly in securities regulation, but in other areas as well. Regulatory cues are neither coercive nor outcome determinative and involve a close intertwining of public and private regulation. The exceptional character of law in this context, and the recent growth in areas where regulatory cues might have fruitful application, may explain why such a role has not previously been analyzed. Yet in securities markets and other industries exhibiting network economies - from electricity transmission and interstate transportation to telecommunications and the Internet - a cueing function for law may be central to efficient transition. It may explain much of why law matters in the modern economy

Automation and robotics for the National Space Program

The emphasis on automation and robotics in the augmentation of the human centered systems as it concerns the space station is discussed. How automation and robotics can amplify the capabilities of humans is detailed. A detailed developmental program for the space station is outlined