A review of household dynamic vehicle ownership models: holdings models versus transactions models

Among disaggregate vehicle ownership models, which model the number and/or type of vehicles owned at the household level, one can distinguish holdings models, which deal with the (optimal) household fleet at a single point in time, and transactions models. The latter type of model explains changes to the household fleet, such as replacement and disposal. The paper describes previous attempts at such dynamic models and sketches how a vehicle transactions model could look (as an example we discuss an application to The Netherlands). This includes discussions of transaction probabilities, two-stage budgeting, introducing vehicle quality in the utility functions, and the envisaged model structure and data it could use.     

Optimized energy management control for the Toyota Hybrid System using dynamic programming on a predicted route with short computation time

Among the general problematic of the HEV power trains, the most critical point is the determination of the power-split ratio between the mechanical and the electrical paths, known as the energy management strategy (EMS). Many EMS are proposed in the literature, and can be grouped in two categories: the local optimization EMS and the global optimization EMS. The local optimization category corresponds to the EMS based on human expertise and the knowledge of the power train components efficiency maps. Thus, the local optimization EMS manages the power train operations by referring to predefined rules. The drawback of such strategies is that it brings an instantaneous fuel consumption optimization, and does not fully optimize the fuel consumption over the whole trip. Therefore, additional fuel savings are still possible. This paper presents an overall optimized predictive EMS for the Toyota Hybrid System (THS-II) power train of the Prius. The proposed EMS is based on Dynamic Programming (DP), where the prior knowledge of the route is required in order to predetermine the power-split ratio and optimize the fuel consumption for the whole predicted route. The DP EMS proposed for the THS-II power train is designed with a very short computation time, intended to be implemented in real-time applications. The potential of this DP-controller in reducing fuel consumption on regulatory cycles are computed and compared to a rule-based controller and to the Prius published fuel consumption results. Finally, the fuel reduction enhancements of the DP-controller are computed for real road tests achieved on a MY06 Prius in Ile-de-France, by comparing to the associated observed consumption measurements.     

Thermodynamic analysis of hydrocarbon refrigerants-based ethylene BOG re-liquefaction system

The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane (R290), butane (R600), isobutane (R600a), and propylene (R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system’s performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600a gives the best performance, followed by (in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.     

Computer modeling and validations of steel gear heat treatment processes using commercial software DANTE

The heat treatment process of a gear made of AISI 9310 carburized steel is modeled using the commercial heat treatment simulation software DANTE. Both carburization and quenching processes affect the residual stress distribution and distortion of heat-treated parts, which are important to service quality and fatigue life. DANTE/VCARB is used to design the boost/diffuse schedule of a vacuum carburization process. Oil quenching is modeled following the vacuum carburization process. Thermal gradient and phase transformation are two main sources of distortion and residual stresses in quenched parts. The relation of the carbon distribution, thermal gradient, and phase transformations during quenching is studied through the gear modeling example. Because of geometry, the residual stress distribution after quenching is non-uniform along the gear surface. In general, the root fillet has higher residual compression than either the root or tooth face locations after traditional oil quenching of carburized gears. The predicted residual stresses from the oil quenching model are imported into a single tooth fatigue bending model. The gear stresses under bending load indicate the possible cracking locations during the bending fatigue test. The importance of heat treatment residual stresses during gear design is pointed out, and it is commonly ignored in the gear design and manufacturing industry.     

Characteristics of VIV in multi-degree-of-freedom tensioned beams using a numerical method

The object of this study is to analyze the characteristics of vortex-induced vibration of a slender marine structure with the numerical method. Applying a dynamic analysis method for a slender marine structure based on the 3D finite difference method, we carried out case studies for a tensioned beam model at a constant flow speed. The hydrodynamic forces, in the direction of inline and cross-flow, created by vortex shedding are simultaneously considered based on Morison equation. The frequency of force in the inline direction corresponding to the unstable zone is evaluated. An eigenvalue analysis for different flow speeds of a tensioned beam considering the effect of the tension increase due to the inline and cross-flow drag forces is performed. We found that a revision of the eigenvalue should be considered if the tension along a riser or beam is significantly affected by an environmental or functional load. From a trajectory on the XY plane it was shown that the riser did not move in an exact 8 shape for all flow conditions due to the phase angle difference between inline and cross-flow displacement. It is believed that the phase angles between inline and cross-flow displacements in high modes are different among the nodes.     

Online public deliberation for a regional transportation improvement decision

This paper investigates the potential for deliberation as a means for public participation in shaping public policy. The paper begins with a summary of deliberative democracy and other concepts that recently have motivated an interest for online deliberation. Next, the paper describes a case study in which 133 public participants deliberated over a regional transportation improvement decision. The deliberation occurred entirely over the internet and lasted for 31 days. The participants wrote hundreds of posts (comments) and made thousands of post-ratings (statements of agreement or disagreement). The posts and three questionnaires are analyzed quantitatively and qualitatively to assess the nature of the deliberation and the participants’ perception of their experience. A negative binomial regression is used to examine which participant characteristics are associated with writing more posts.     

Congestion and emissions mitigation: A comparison of capacity,demand, and vehicle based strategies

Capacity, demand, and vehicle based emissions reduction strategies are compared for several pollutants employing aggregate US congestion and vehicle fleet condition data. We find that congestion mitigation does not inevitably lead to reduced emissions; the net effect of mitigation depends on the balance of induced travel demand and increased vehicle efficiency that in turn depend on the pollutant, congestion level, and fleet composition. In the long run, capacity-based congestion improvements within certain speed intervals can reasonably be expected to increase emissions of CO₂e, CO, and NO_x through increased vehicle travel volume. Better opportunities for emissions reductions exist for HC and PM_2.5 emissions, and on more heavily congested arterials. Advanced-efficiency vehicles with emissions rates that are less sensitive to congestion than conventional vehicles generate less emissions co-benefits from congestion mitigation.     

Fisheries–Marine Protected Area–Tourism Interactions in Moalboal,Cebu, Philippines

The development of Integrated Coastal Management (ICM) in the Philippines has been underway for more than 30 years. As coastal communities continue to face dwindling resources from both the land and sea, marine protected areas (MPAs) have been regularly utilized as a community-based marine conservation tool. Recently, marine tourism has begun to exert influence as a driver utilized by local communities to promote the establishment of MPAs. Revenue generated through user-fee systems has begun to influence and shape broker–local–tourist (BLT) interactions in Moalboal, Cebu, Philippines. In this article, an account of the social dynamics surrounding MPAs is presented, sources of tension are identified, and recommendations proposed.